WHAT IS A VALVE?
Industrial valves or "valves" are equipment used to stop, start and regulate flow in piping systems.
One of the most important features of valves can be opening and closing the flow path (like a switch), increasing and decreasing the flow rate (flow speed regulator), adjusting pressure, adjusting temperature, separating one part of the system from other parts (isolation), protecting the system. In critical situations, he pointed out to turn the direction in one direction and reverse the direction of the flow.
What are the types of VALVE ?
Considering these criteria, the types of wheels are:
Rotary valve:
By turning one turn or 90 degrees with a turn more or less than 90 degrees Types of valves based on function in the system: Isolation valve or isolation valve, control valve or regulating valve, safety valve or safety valve, non return valve Valve with special function
Types of valves based on the type of connections:
threaded valve or screw valve Flanged valve boiled milk a silent lion was born Wafer milk and log milk Classification of valve types based on different criteria such as valve performance inthe system, movement mechanism of the blocking elementActuator energy source connections And the type of blocking element is done.
Types of valves based on the movement mechanism of the flow blocking element:
linear valve:
with the rotary operator
with the axial operator
Types of valves based on the mechanism of the operator:
manual valve
The milk has an automatic milk feeding source
Types of valves based on the type of blocking element: sliding valve
ball valve
plug valve
piston valve
diaphragm valve
butterfly milk
throat milk
Spherical milk
needle valve
Pressure relief valve
The valve is one way
Classification of valve types based on the movement mechanism of the flow blocking element:
Changing the position of the valve actuator manually, with an energy source or automatically, causes the movement of the stem and the blocking element (disc, rod or flexible material). This movement provides the possibility of stopping, starting or adjusting the fluid flow.
According to the way the disc moves, the types of valves can be divided into two general groups: valves with linear motion and valves with rotary motion.
Classification of valve types based on the movement mechanism of the flow blocking element:
Changing the position of the valve actuator manually, with an energy source or automatically, causes the movement of the stem and the blocking element (disc, rod or flexible material).
This movement provides the possibility of stopping, starting or adjusting the fluid flow.
According to the way the disc moves, the types of valves can be divided into two general groups:
valves with linear motion and valves with rotary motion
Diaphragm valve (linear valve with rotary actuator) in open and closed position:
In general, the speed of flow change in linear valves is lower than in rotary valves. However, these lions are more accurate and stable.
The blocking element of these valves, when placed in the open position, is completely removed from the flow path
Types of linear valves w
WHAT IS A VALVE?
Industrial valves or "valves" are equipment used to stop, start and regulate flow in
piping systems.
One of the most important features of valves can be opening and closing the flow
path (like a switch), increasing and decreasing the flow rate (flow speed
regulator), adjusting pressure, adjusting temperature, separating one part of the
system from other parts (isolation), protecting the system. In critical situations, he
pointed out to turn the direction in one direction and reverse the direction of the
flow.
What are the types of VALVE ?
Considering these criteria, the types of wheels are:
Rotary valve:
By turning one turn or 90 degrees with a turn more or less than 90 degrees
Types of valves based on function in the system: Isolation valve or isolation valve, control valve or regulating valve, safety valve or safety valve, non-return valve Valve with special function
Types of valves based on the type of connections:
threaded valve or screw valve Flanged valve boiled milk a silent lion was born Wafer milk and log milk Classification of valve types based on different criteria such as valve performance inthe system, movement mechanism of the blocking elementActuator energy source connections And the type of blocking element is done.
Types of valves based on the movement mechanism of the flow blocking element:
linear valve:
with the rotary operator
with the axial operator
Types of valves based on the mechanism of the operator:
manual valve
The milk has an automatic milk feeding source
Types of valves based on the type of blocking element: sliding valve
ball valve
plug valve
piston valve
diaphragm valve
butterfly milk
throat milk
Spherical milk
needle valve
Pressure relief valve
The valve is one way
Classification of valve types based on the movement mechanism of the flow blocking element:
Changing the position of the valve actuator manually, with an energy source or automatically, causes the movement of the stem and the blocking element (disc, rod or flexible material). This movement provides the possibility of stopping, starting or adjusting the fluid flow.
According to the way the disc moves, the types of valves can be divided into two general groups: valves with linear motion and valves with rotary motion.
Classification of valve types based on the movement mechanism of the flow blocking element:
Changing the position of the valve actuator manually, with an energy source or automatically, causes the movement of the stem and the blocking element (disc, rod or flexible material).
This movement provides the possibility of stopping, starting or adjusting the fluid flow.
According to the way the disc moves, the types of valves can be divided into two general groups:
valves with linear motion and valves with rotary motion
Diaphragm valve (linear valve with rotary actuator) in open and closed position:
In general, the speed of flow change in linear valves is lower than in rotary valves. However, these lions are more accurate and stable.
The blocking element of these valves, when placed in the open position, is completely removed from the flow path
Types of linear valves with rotary actuator:
Linear valves with a rotary actuator usually use the rotation of a fasten stem to move the flow blocking element.
Flakh is one of the common types of operators used in this type of shirah. Types of linear valves with rotary actuators include sliding valves, spherical valves, diaphragm valves, needle valves, and throat valves.
These valves are used in most cases to control the flow.
Types of linear valves with axial actuator:
In linear valves with an axial actuator, the movement of the blocking element is done by pneumatic or electromagnetic force in a specific axis. Coaxial valves, angular valves and solenoid valves are types of linear valves with axial actuators. The speed of the actuator in this type of valve is higher than the valves with rotary actuators.
Valves with axial actuators are only used to stop or start the fluid flow and are not useful in regulating the flow.
The picture below shows how this type of valve works
Angular valve (linear valve with axial actuator) in open and closed position
Types of valve with rotary movement or valve with single movement:
"Rotary Motion Valve" stops, starts or adjusts the fluid flow during the rotary movement of the blocking element.
In this type of valve, a disc is usually used as a blocking element in the direct flow path.
In most cases, the rotation of one quarter or 90 degrees of the actuator puts the disc in the open or closed position.
However, some types of valves change their position with a rotational movement in the range of less or more than 90 degrees. In this type of valve, the actuators can be Used grips or arrows
Butterfly valve (valve with rotating movement) with the arrow actuator in half open position:
The valve is fully closed at 0 degree angle and fully opened at 90 degree angle by turning one quarter. The picture above shows the structure of samples of this type of valve.
The speed of changing the position of the valve with rotary movement is much higher than that of the valve with linear movement.
The most widely used types of rotary valves are ball valves, samouri valves, butterfly valves and one-way valves. In some divisions, rotary valves are placed in two separate groups with 90 degree valves.
For example, propeller shafts are considered of the types of rotary valve and single valve. In this case, valves with a hinged disk (such as a one-way valve) are only included in the group of rotary valves. Classification of valve types based on performance.
What is volo isolation or volo isolation?
Isolation valve or isolation valve is a device used to stop the flow of fluid in place
Certain piping systems are used for maintenance or safety purposes. This type of valve is also used in determining the direction of flow and connecting the output equipment to the piping system. The isolation of a valve indicates its function in the system and does not indicate its structure.
For this reason, many types of valves are included in the isolation valve group. In some cases, these valves are also called "Block Valve" Isolating valve in the way of the water transfer pipe to the sink To better understand the function of the isolation valve, consider the sink in the sanitary facilities of the building.
Normally, the water flow towards the sink faucets is always open. However, if these valves need to be repaired, the open water flow will interfere with the repair process.
For the same reason, an isolation valve (usually a ball type) is installed in the plumbing path under the sink. Closing this valve cuts off the flow of water inside the control valves of the sink and makes it possible to repair or replace them. Industrial piping also has a similar function.
What is control valve or control valve?
The control valve, "Control Valve" or "Throttle Valve", is one of the types of valves for adjusting operational parameters in piping systems. This type of valve is used to directly adjust the speed and flow capacity.By controlling these parameters, it is possible to indirectly change dependent parameters such as temperature, pressure and liquid level. It is used in the system.
Control valves are also known as "Regulating Valve" Spherical valve of all kinds of control valves Ball valve, needle valve, butterfly valve, diaphragm valve, ball valve, samouri valve and throat valve are types of valves that can be used as control valves. Among these cases, spherical lions are more popular.
Most of the control panels use automatic actuators to adjust and control the flow.
Some of these have other uses as well.
For example, ball valves are also used as isolation valves.
What is a safety valve?
The safety valve is a protective device used to prevent damage to pressurized equipment and piping systems when the pressure increases too much or when a vacuum is created.When the system pressure exceeds the amount specified in the design documentation (permissible operating pressure) or unwanted vacuum conditions occur in the system, the possibility of damage to equipment or personnel increases.
In this situation, safety valves return the pressure of the system to a safe state at a high speed. There are different criteria for dividing these lions.
For example, safety valves are divided into types of safety valves with low lift (automatic), full lift and full bore (full section) based on the way the disc is moved
What is non-return valve or check valve?
"Check Valve" is one of the types of valves used to prevent return flow in piping systems.
This type of valve is called "Non-Return Valve" or "NRV" for short. " is also known. The pressure caused by the flow of fluid in a specific direction moves the blocking element upwards and opens the path.
Due to the one-sided direction of the opening of the blocking element, the movement of the fluid in the opposite direction causes The path will be closed.
The picture below shows the functioning mechanism of the check valve very well Juices with special performance In some cases, the valves used in the plumbing system are used to perform a function that cannot be performed by the types of valves introduced in the previous sections.
Among the types of valves with special functions, we can mention multi-way valve, floating valve, suction valve, guillotine valve and linear blind valve. We will introduce these items in the next sections.
Division of valve types based on operator Types of valves based on the type of operator and how to use valves with a manual operator, valves Mezhz are divided into energy source and valves with automatic operator:
manual valve: To adjust and change the state of the fluid flow, the valves use a lever, a handle, a gear lever or a chain.Even if connected to the energy source:
These valves analyze the flow state by using electric (motor or solenoid), pneumatic (compressor), hydraulic (pump) and electromechanical (solenoid) energy and change it if needed.
Automatic valve:
These valves do not need manual force or other energy sources to change the flow state. In other words, automatic valves change status according to the system requirements. The pressure relief valve is one of the types of automatic valves Classification of valve types based on connections One of the factors affecting the quality and efficiency of all types of valves is the connections used to install them in the piping system.
There are several ways to connect the valve to the pipe. Most of the valves are installed in the piping network using screw or fast connections, flanges, welding, silent welds, wafers and logs. Each of these connections is suitable for specific loads and operating conditions.
The image below shows some of the connections used for all types of valves Flanged connections in all types of valves Most of the valves are made by flange connections and installed in the piping system.
Installing and opening this type of connection is easier than other types. In order to ensure the proper sealing of the valve, a gasket is placed on the surface of the flange. The solids used in these solutions are metallic, nonmetallic or a combination of the two.
In general, flanged plates are larger than 15 mm and are made of bronze, iron and steel Screw or fasting connections in all types of valves
For the screw connection of all types of valves and piping systems, several threads are created on the end of the valve and pipe.
In this type of connections, sealing seams (on the threads) and gaskets (between the surfaces of the connections) are responsible for preventing fluid leakage. Plates with screw connections are usually used in pipe lines with a diameter of less than 150 mm.
These plates They are mostly made of bronze and in some cases made of iron and steel.Usually from the picture below, it shows a ball valve with a screw end Welded joints in all types of valves
Plates with welded connections are only used for steel pipes with a pipe size of 50 mm and above.
In order to implement welding connections, the end of the valve is machined so that it can be easily inserted into the pipe. After placement, welding is done around the joint.
This method is used for systems with high operating pressure and systems without the need to open the valve
Among the other connections used to install all types of valves in the piping network, the following can be mentioned:
Weld silent connection:
Suitable for low pressure systems Push connection:
Suitable for low pressure systems, copper pipes and steel pipes with a diameter of less than 65 mm.
Wafer connection and log:
Suitable for limited spaces, control valves and butterfly valves
One of the most important criteria for the classification of valve types is the type of disc and its mechanism of operation.
In the next section, we will give a complete introduction of each type of valve based on these criteria.
What is gate valve or sliding valve and how does it work?
Sliding valve, gate valve or "Gate Valve" is the most common type of valve in process factories. This valve, with its linear function, causes fluid to stop or pass through the piping system.
Sliding valves are fully open or fully closed. In other words, these valves are not used in fluid flow control.
The animation below shows how this type of valve works Mechanism of operation of sliding valve
According to the picture above, the gate valve uses a sliding disc (gates) or wedges as a blocking element.
The up and down movement of this disc causes the fluid flow path to open and close.
In order to achieve proper sealing of the flow path, in The entire surface of the disc must be in contact with the seat when the valve is fully closed.
These valves should not be used to control or regulate flow Sliding valve components According to the picture above, the valve gate components are:
Mehreh Falkh Falkh
The stem nut, the yoke nut, the place for lubricating the stem screw
nut
Gland flange
Gland or felt packing, back seat, lid, screws or studs, seals, lids, stoppers, barriers, seats, body, body
Types of sliding valves There are different criteria for dividing the types of sliding valves. These logs are divided into the following types based on the type of gate, cap connection and stem movement mechanism:
Types of sliding valves based on the type of gate or disc Sliding valve with solid conical wedge Sliding valve with flexible wedge Sliding valve with two-piece wedge Types of sliding valves based on body cap connection Screw cap, nail cap, welding cap, pressure cap Types of sliding valves based on the way the stem is moved Rising sliding valve (external stem and screw) non-rising sliding valve Advantages and disadvantages of sliding valve
The most important advantages of sliding boards are:
Providing a very good seal
Very low pressure drop during fluid passage
Can be used in both directions
Suitable for use in high temperature and pressure
Low maintenance requirements
Can be used for different types of fluids such as steam, oil, slurry and fluids with high viscosity
The following are the main limitations of sliding valves:
Inability to use to control fluid flow Low speed of opening and closing the path (although this feature is also considered as an advantage to reduce the possibility of damage to the valve) Making noise and vibration if it is incompletely opened It is difficult to repair the seat because of the limited access to the internal components
What is a ball valve or ball valve and how does it work?
The ball valve or "ball valve" is one of the types of rotary valve that uses a spherical (ball-shaped) barrier to stop or pass fluid in the piping system. Most of the ball boards are of fast action type and operate by turning 90 degrees at the handle. Valves connected to gas pipes inside buildings are usually ball valves. The moving picture below shows the functioning mechanism of these valves very well.
Mechanism of operation of ball valve
Opening and closing large ball valves requires considerable force. In these cases, rotary actuators are used to open and close the valve. Wing and valve components The different parts of a standard ball valve are shown in the figure below Ball valve component The sections indicated in the above image are:
the body
seat
Ball disc
Gasket or sealing washer
Screw or stud
nut
cover / body
Oring
Washer
Seal
Gland (a kind of felt tile used as waterproof insulation) Gland flange handle
screw
stem
Types of ball valves
There are different types of ball valves, they are divided into the following types based on the structure and direction of fluid flow:
Types of ball valves based on structure Sahrahi ball valve, floating ball valve, ball valve with axial installation Types of ball valves based on fluid flow direction Ball valve with top entry (one piece), ball valve with side entry (two pieces), three piece ball valve Advantages and disadvantages of ball valves The benefits of Bal Velo can be mentioned as follows:
Fast operation due to 90 degree rotation (suitable for quick stoppage of operation in case of necessity)
Minimizing leakage Smaller dimensions and lighter weight compared to sliding boards of the same category High flexibility in design and reducing the need for more valves Variety of dimensions and shapes
Safe operation at high operating pressure and temperature (if the quality of construction is high), better control with less force No need for lubrication Some of the limitations of ball valves are:
Lack of proper performance in situations requiring flow regulation
The possibility of accumulation of sediments of slurry fluids in the valve holes and increased wear of the valve.
Limitation of usable operating temperature range What is samouri milk and how does it work?
Samavari valve or "Plug Valve" is one of the types of valve with rotary movement system, it is usually used to control the flow of gas and liquid fluids. The blocking element in this type of valve is in the form of a cone or cylinder with It is the conduit for fluid passage.
The rotation of the cone and the alignment of its conduit along the pipeline route allows the movement of fluid flow in the system. The moving image below shows the structure and operation of one of the common types of check valves
The components of the Velo plug are:
handle (operator)
Grease-proof (fittings or connections used to enter lubricating materials) stem
Gland packing
packing
plug clamp
the body
Blocking element or plug (in closed state)
Duct or plug port (rectangular type)
Lubrication groove
All kinds of Velo Samavari
Samavari valves use cylindrical or conical discs to control fluid flow.
The types of Samari valves based on the structure and specifications of the port are:
Types of Samavari milk based on lubrication system
Samavari faucet with lubrication system Samavari faucet without lubrication system
Types of Samavari valves based on the shape of the disk port Samavari faucet with rectangular port
Samavari faucet with circular port Samavari faucet with rhombus-shaped port Types of Samavari valves based on the number of ports The plug is two ways, the plug is three ways, the plug is four ways Advantages and disadvantages of samovar milk Among the advantages of plug-in, the following can be mentioned:
Simple design with few parts High speed of opening and closing the fluid flow path
The possibility of performing repair and maintenance directly in the system Minimum resistance to current Providing a leak-free path Reducing the number of valves required in the system due to the possibility of designing multiple jets and changing the direction of the fluid flow Some of the limitations of samovar lions are:
The force required to open and close is high, due to high friction, it is not possible to use a manual operator for large valves.
Pressure drop caused by reducing the cross-section of the track High cost compared to ball valves with similar dimensions and class
What is piston valve or piston valve and how does it work?
A piston valve or "piston valve" is one of the types of linear valves used to control fluid flow.
This type is very useful
It is widely used in steam engines.
Piston valves are also used in gas and chemical fluid piping systems. These valves provide the possibility of stopping and starting the fluid flow according to the system condition. The function of the piston valve is similar to the spherical valve. With this difference, in this type, a piston is used instead of a spherical disk
What is a diaphragm valve and how does it work?
Diaphragm valve or "diaphragm valve" is one of the types of valve with linear movement mechanism and it is used to stop, start and regulate fluid flow. In the common type of this valve, it is made of a diaphragm (flexible disk).
The name of the flow blocking element and a raised surface on the bottom of the valve is used as the seat of the disc. Although the diaphragm is used in the piping of sanitary facilities, power plants, petrochemical plants, construction projects, mining projects and pharmaceutical factories. The following animation shows the general mechanism of this type.
It displays the valve Diaphragm valve components According to the picture above, the components of diaphragm valves are:
cap master bolt connecting the stem to the diaphragm In-diaphragm amplifier stem sheath
leg
Compressor
screw hole
The seal between the diaphragm and the body band or saddle (seat)
Fluid passage
Diaphragm movement channel
valve end connections (flange type) Diaphragm valve types
Based on the structure of the seat, diaphragm valves are divided into two main types: saddle or appendage and straight or smooth.
The picture below shows the difference between these two types of diaphragm valves. Straight diaphragm valves are usually used to control or regulate fluid flow.
The saddle type of these boards are a good choice for controlling the flow of abrasive and corrosive fluids
Advantages and disadvantages of diaphragm valve The following are the main advantages of diaphragm panels:
Complete blockage of flow, proper sealing and no leakage Easy maintenance and repair
No interference of repair operations with system performance
The following are some of the main limitations of diaphragm valves:
limited usable operating pressure (pressure around 21 bar) Limitation of usable operating temperature (temperature from -50 to 204 degrees Celsius) Mandatory use of corrosion-resistant body
The possibility of preventing complete drainage of the system (in the saddle type)
What is a butterfly valve and how does it work?
Butterfly valve or "Butterfly Valve" is another type of valve with a 90-degree rotation and control function. The rotational movement of circular or rectangular discs in this type of valve allows stopping, adjusting and starting the flow in systems.
Provides piping.The reason for the rotation of a valve actuator is the speed of flow adjustment using this valve. Butterfly valves are used in systems where there is no need to disconnect and connect the current.
These valves are used to control the flow of various gaseous, liquid and slurry fluids in various industries (even with high operating pressure and temperature)
Function mechanism of butterfly valve:
The actuator of the butterfly valve usually has a rib that connects the blade to the stem. This configuration reduces the required power and reduces the speed of current regulation. During installation, the valve must be in the open position. The closing of the propeller valve during the installation operation results in the seat being in front of the disk and difficult opening of the valve Butterfly valve components
According to the picture above, the main parts of the propeller valve are:
Flakhai actuator
rib cage
leg
the body
Disc
Seat
Types of butterfly valves
The types of butterfly valves based on the general structure and configuration of the stem are: Types of butterfly valves based on the structure Flanged butterfly valve
Wafer butterfly valve, log butterfly valve (around the hole), welded butterfly valve
Types of butterfly valves based on the difference between the disc axis and the stem axis
Butterfly valve without deviation (concentric) Butterfly valve with double deviation Butterfly valve with triple deviation
Advantages and disadvantages of butterfly valve
The following are the main advantages of butterfly valves: Occupying less space and less weight than other valve types
Low operating time
Keep the cost relatively low
Low pressure drop in the valve path
Can be used to pass chemical or corrosive fluids because it is equipped with a non-metallic seat
The following introduces some important limitations of the butterfly valve: Limited control and adjustment due to the low range of operating pressure difference and the opening of 30 to 80 degrees in the disc The possibility of cavitation and flow suffocation due to constant oscillation of the disc Poor sealing
What is a pinch valve and how does it work?
Throat valve or "pinch valve" is one of the types of valve with linear function, which consists of a flexible rubber duct. There is no equipment in the path of flow through the throat valve. However, the movement of two rods in Up and down the path, it provides the possibility to stop or start the flow completely. The pinch valve is a good choice for stopping, regulating and passing fluids with solid particles. For this reason, this valve is often used in the food industry, construction projects and pharmaceutical factories.
Components of throat milk Takes According to the picture above, the components of throat milk are:
Flakhai operator
Stem or axis
Lower disc
Upper disc
Rubber conduit
the body
Types of throat valves
The classification of types of throat valves is done according to different criteria as follows:
Types of throat valves based on body structure
Open throat valve
close throat milk
Types of throat valves based on the implementation mechanism Manual pneumatic hydraulic
Types of throat valves based on the type of sheath (current flow path) Standard two-layer sheath, conical sheath, variable sheath Advantages and disadvantages of throat milk The advantages of Pinch and Veloha are:
Suitable for abrasive and corrosive fluids
Low weight, small size and simple design
Minimal fuss and friction Providing a direct and unobstructed path for fluid flow No pollution Relatively fast mechanism Low construction and maintenance cost due to simple design The need for low maintenance and easy replacement of components The following points introduce the general limitations of throat milk types:
Not suitable for high operating pressure and temperature The possibility of damaging the rubber sheath or changing its shape in the high pressure difference is not suitable for vacuum systems Not suitable for turbulent flows Mechanism of action of ball valve The structure of spherical valves is very similar to the structure of sliding valves. However, due to the better contact angle between the cone or the sphere and the seat, the leakage of the spherical valves is less and their sealing is better. Globes and valves are usually used in systems that require complete sealing. Although this type is suitable for conditions where pressure drop is not an important issue.
Spherical valve components As we mentioned, the structure of the globe valve is very similar to sliding valves. The following picture shows the different components of this type of valve
The components of spherical valve are:
Mehre Falkh Flakh
leg yoke nut Master Bolt nut Gland flange Gland Insulation
Back seat
Master Bolt
nut
cap
Cap washer
the body
disc nut
Disc
Seat
Types of spherical valves
Spherical valve types are divided based on disc shape, body structure and body cover connections as follows:
Types of spherical valves based on disc Hub disc, needle disc, combined disc Types of spherical milk based on the body Ball valve z shape ball valve Y shape angular ball valve Types of ball valves based on cap connections
Screw cap Stud cap, welding cap, pressure or thermal cap Advantages and disadvantages of spherical milk
Due to the structural similarities of spherical valves and sliding valves, the characteristics of these two are usually compared to each other.
The following are the most important advantages of spherical valves:
Better blocking of the path than sliding doors Suitable for continuous opening and closing without worrying about the wear of the seat and disc. Easy repairs due to the access to the seat and disc from the top of the valve.
High execution speed compared to sliding valves due to the shorter length of the stem round trip ThemainlimitationsofGlob Thepossibilityofusinganautomaticoperator and Veloha are:
High pressure drop due to the existence of many obstacles in the path of fluid flow The possibility of damage to internal components in large and high- pressure lines due to disturbances and multiple impacts
The need for a lot of force to open and close large valves and making noise during use is more expensive than sliding valves.
What is a needle valve and how does it work?
Needle valve or "Needle Valve" is a type of industrial valve that controls, regulates or completely stops the fluid flow by using a needle barrier.
This type of valve is used to continuously regulate the flow in systems with Low flow rates are used. The design of needle valves is similar to the design of ball valves. All manual instrumentation in the piping system is installed with a needle valve.
By controlling the input flow, this valve prevents damage to precision ThecomponentsofNidel instrumentsduetoasuddenincreaseinpressure Velo are:
faucet handle
nut
cap
the body
seat
Handle screw
leg
packing
Oring
Types of needle valves
The types of needle valves are divided into the following according to the type of actuator and the direction of the stem in relation to the fluid flow:
Based on the type of operator
Manual needle valve, electric or pneumatic needle valve Based on the direction of obstruction
Linear needle valve, angular needle valve Advantages and disadvantages of needle valve
The main advantages of Nedel and Loha are:
The possibility of precise fluid control at very low flow intensity Not occupying much space due to small dimensions The possibility of adjusting the flow even at a low fluid flow rate Very high accuracy of flow rate adjustment Simple operation Among the limitations of needle valves, the following can be mentioned:
Pressure loss due to high ability to block fluid flow path Can only be used for lower rates The possibility of damage to the valve seat and needle if there are solid particles in the fluid composition Impossibility of opening or closing the valve immediately (damage to the valve components in case of rapid opening and closing)
What is a relief valve and how does it work?
Pressure Relief Valve" is one of the types of control valves used to drain the " fluid when the pressure increases too much and restore the system pressure to a safe level.
The main goal of using pressure relief valves is to increase the lifespan of equipment by preventing possible damage in critical conditions.
The animation below shows the mechanism of the relief function when excess Thereliefvalvemustbeabletofunctionproperlyand pressureoccurs correctly in all conditions and at every moment of the fluid transfer process in the system.
Therefore, the only source of energy needed to change the state in it is the energy resulting from the passage of the fluid. In other words, this type of actuator works automatically.
Valve relief components
In the picture below, different parts of one of the standard types of pressure relief valves are shown
The components of the pressure relief valve are:
hat Adjustment screw lock nut
The top plate of the spring cap
leg
spring
The lower plate of the spring closed
Split ring
gasket
Guide bush
pin
Ball
Disc
seat
the body
Types of pressure relief valves There are many types of pressure relief valves, the most common of which can be mentioned as follows:
Types of pressure relief equipment based on the closing mechanism Automatic manual Types of pressure relief equipment based on structure Typesofpressurereliefequipment Normal(spring)balancedpilotlantern Pressure relief vacuum breaker relief Pressure based on control parameters Advantages and disadvantages of pressure relief valve and vacuum breaker The most important advantages of the pressure relief valve are:
Can be used in all gas and liquid piping systems Suitable for use in high temperature and pressure Low cost compared to other valve types The limitations of the pressure relief valve include the following:
Negative effect of back pressure on valve performance The possibility of spring corrosion if corrosive fluids pass through the system Not suitable fo high risk systems In balanced discharge valves, the defects related to back pressure and the possibility of spring corrosion have been removed.
However, in these types of boards, there is a possibility of failure due to fatigue in the spring and the need for a separate washing system What is a one-way valve and how does it work?
One-way valves are types of non-return valves and are used to prevent fluid from moving against the specified flow path.
These valves provide the possibility of unobstructed fluid flow and closing the path if the pressure is low.
How to use one-sided boards depends on the mechanism of their types.
In general, one-way valves are a good choice for installation in fluid discharge systems such as pump and compressor paths.
The animation below shows the operation of one type of one-way valve The check components are:
the body
seat
Nut connecting the hinge to the disk, pin connecting the hinge to the washer disk
Disc
Hinge
Hinge connection pin with gasket body
cap
Nut for connecting the cover to the body, master bolt for connecting the cover to the body All kinds of even one-sided
One-sided lions are divided into different groups based on their structure and functioning.
Among the most common types, even on one side, the following :
can be mentioned
Oscillating check valve
One-way valve, hinged from above, angled one-way valve One-way pressure valve
One-way piston valve, one-way ball valve
One-way valve with two-piece disc One-way valve disconnecting advantages and disadvantages of one-way valve
Check valves are used in all cases to prevent fluid flow from returning. Therefore, their main advantage is their use.
Among the side advantages of the one-way valve, the following can be mentioned:
Maintain system pressure
Can be used as a backup system
Can be used in horizontal and vertical directions
The main limitations of one-sided valves are:
Impossibility of use in fluctuating and disturbed systems The possibility of increasing the rate of depreciation due to the sudden closing of the disk Despite the limitations of the check valve, this type of valve is considered the best option to prevent backflow in the piping system. Types of valves with special use In the previous sections, we introduced the most well-known and widely used types of valves used in piping systems. Some types of valves are designed and used for special applications.In this section, we briefly examine the use and structure of some special boards
What is a tubular valve or solenoid valve?
Solenoid valve is a type of control valve with an electromechanical actuator, which is used to block, start, measure, distribute or mix fluid flow.This type of valve has a high operating speed, It has good reliability, long life, compatibility with all kinds of materials, low energy consumption and small dimensions. Solenoid valves are used in fluid flow control of cylinders, hydraulic motors or Large industrial valves are used.
Many mechanized irrigation systems also use these trees. The following picture shows the different components of this type of valve
1) Coil
2) Armature 3) Shaded pole 4) Spring
5) Plunger
6) Seal
7) Body
When the electric current passes through the solenoid valve, a magnetic field is created around the coil. This field causes the plunger to move towards blocking the flow path. In fact, the solenoid valve converts the electrical energy into the mechanical energy needed to control and regulate the flow
What is reducing valve or reducing valve?
The pressure reducing valve or "Reducing Valve" is one of the types of valve with hydraulic actuator and diaphragm disc, which is used to reduce the pressure of the upstream flow and transfer the flow with lower pressure to the downstream. In fact, this type of valve , by removing disturbances and pressure fluctuations in the upstream, it causes continuity and stability of the pressure in the downstream of the system.
The disk reducing valve is usually in the open state. This type of valve is used in air compressors, aerospace equipment, gas cutting and welding, pressure reactors, mining equipment and City water pipes can be used
What is a floater?
The float valve, "Float Valve" or floater, is a type of control and isolation valve with a special operator, which is used to check the amount of fluid and stop the flow.
The most well-known type of float valve is the floater used in water coolers. Of course, floating valves are used in water tanks, refrigeration plants, building sanitary facilities and industrial plumbing systems (among other types of valves).
Despite the variety of industries and places where they can be used, the mechanism of operation of most floaters is similar.
The animation below shows how the floating valve works
What is a fixed cone valve?
Fixed Cone Valve" (Fixed Cone Valve) is one of the types of valve with linear " movement and control function, it is often used as a turbine auxiliary valve, reservoir emptying valve (especially dam reservoirs) or continuous flow control valve.
If the fluid pressure increases, the cone embedded in the center of this valve is guided to the outside.
This mechanism provides the possibility of emptying the fluid from around the cone and adjusting the pressure of the system upstream of the valve
What is multi-way milk?
The multi-way valve or "Multiport Valve" is one of the types of valves with a special use, where the flow blocking element consists of several channels or so-called ports.
Several usage modes are defined on the operator of these valves. Changing the state of the operator and placing it on each state determines the direction of the fluid flow.
In this way, it is possible to enjoy several functions using one valve By placing the operator of this valve on different positions, it is possible Direct the water passing through the piping system towards the filter (purification) or the sewer (empty). Other situations allow the possibility of closing the path, reversing the flow, bypassing the filter path and many other capabilities.
What is a valve manifold?
The manifold valve or "manifold valve" is a tool consisting of several valves, which is used to change or calibrate the pressure transmitter in the piping system (without the need to stop the flow transfer process).
There are three main types of manifold valves. They are divided into one way, three ways and five ways. Opening and closing the path of different valves in these valves allows checking the system performance and calibration of the instruments.
ith rotary actuator:
Linear valves with a rotary actuator usually use the rotation of a fasten stem to move the flow blocking element.
Flakh is one of the common types of operators used in this type of shirah. Types of linear valves with rotary actuators include sliding valves, spherical valves, diaphragm valves, needle valves, and throat valves.
These valves are used in most cases to control the flow.
Types of linear valves with axial actuator:
In linear valves with an axial actuator, the movement of the blocking element is done by pneumatic or electromagnetic force in a specific axis. Coaxial valves, angular valves and solenoid valves are types of linear valves with axial actuators. The speed of the actuator in this type of valve is higher than the valves with rotary actuators.
Valves with axial actuators are only used to stop or start the fluid flow and are not useful in regulating the flow.
The picture below shows how this type of valve works
Angular valve (linear valve with axial actuator) in open and closed position
Types of valve with rotary movement or valve with single movement:
"Rotary Motion Valve" stops, starts or adjusts the fluid flow during the rotary movement of the blocking element.
In this type of valve, a disc is usually used as a blocking element in the direct flow path.
In most cases, the rotation of one quarter or 90 degrees of the actuator puts the disc in the open or closed position.
However, some types of valves change their position with a rotational movement in the range of less or more than 90 degrees. In this type of valve, the actuators can be Used grips or arrows
Butterfly valve (valve with rotating movement) with the arrow actuator in half open position:
The valve is fully closed at 0 degree angle and fully opened at 90 degree angle by turning one quarter. The picture above shows the structure of samples of this type of valve.
The speed of changing the position of the valve with rotary movement is much higher than that of the valve with linear movement.
The most widely used types of rotary valves are ball valves, samouri valves, butterfly valves and one-way valves. In some divisions, rotary valves are placed in two separate groups with 90 degree valves.
For example, propeller shafts are considered of the types of rotary valve and single valve. In this case, valves with a hinged disk (such as a one-way valve) are only included in the group of rotary valves. Classification of valve types based on performance.
What is volo isolation or volo isolation?
Isolation valve or isolation valve is a device used to stop the flow of fluid in place
Certain piping systems are used for maintenance or safety purposes. This type of valve is also used in determining the direction of flow and connecting the output equipment to the piping system. The isolation of a valve indicates its function in the system and does not indicate its structure.
For this reason, many types of valves are included in the isolation valve group. In some cases, these valves are also called "Block Valve" Isolating valve in the way of the water transfer pipe to the sink To better understand the function of the isolation valve, consider the sink in the sanitary facilities of the building.
Normally, the water flow towards the sink faucets is always open. However, if these valves need to be repaired, the open water flow will interfere with the repair process.
For the same reason, an isolation valve (usually a ball type) is installed in the plumbing path under the sink. Closing this valve cuts off the flow of water inside the control valves of the sink and makes it possible to repair or replace them. Industrial piping also has a similar function.
What is control valve or control valve?
The control valve, "Control Valve" or "Throttle Valve", is one of the types of valves for adjusting operational parameters in piping systems. This type of valve is used to directly adjust the speed and flow capacity.By controlling these parameters, it is possible to indirectly change dependent parameters such as temperature, pressure and liquid level. It is used in the system.
Control valves are also known as "Regulating Valve" Spherical valve of all kinds of control valves Ball valve, needle valve, butterfly valve, diaphragm valve, ball valve, samouri valve and throat valve are types of valves that can be used as control valves. Among these cases, spherical lions are more popular.
Most of the control panels use automatic actuators to adjust and control the flow.
Some of these have other uses as well.
For example, ball valves are also used as isolation valves.
What is a safety valve?
The safety valve is a protective device used to prevent damage to pressurized equipment and piping systems when the pressure increases too much or when a vacuum is created.When the system pressure exceeds the amount specified in the design documentation (permissible operating pressure) or unwanted vacuum conditions occur in the system, the possibility of damage to equipment or personnel increases.
In this situation, safety valves return the pressure of the system to a safe state at a high speed. There are different criteria for dividing these lions.
For example, safety valves are divided into types of safety valves with low lift (automatic), full lift and full bore (full section) based on the way the disc is moved
What is non-return valve or check valve?
"Check Valve" is one of the types of valves used to prevent return flow in piping systems.
This type of valve is called "Non-Return Valve" or "NRV" for short. " is also known. The pressure caused by the flow of fluid in a specific direction moves the blocking element upwards and opens the path.
Due to the one-sided direction of the opening of the blocking element, the movement of the fluid in the opposite direction causes The path will be closed.
The picture below shows the functioning mechanism of the check valve very well Juices with special performance In some cases, the valves used in the plumbing system are used to perform a function that cannot be performed by the types of valves introduced in the previous sections.
Among the types of valves with special functions, we can mention multi-way valve, floating valve, suction valve, guillotine valve and linear blind valve. We will introduce these items in the next sections.
Division of valve types based on operator Types of valves based on the type of operator and how to use valves with a manual operator, valves Mezhz are divided into energy source and valves with automatic operator:
manual valve: To adjust and change the state of the fluid flow, the valves use a lever, a handle, a gear lever or a chain.Even if connected to the energy source:
These valves analyze the flow state by using electric (motor or solenoid), pneumatic (compressor), hydraulic (pump) and electromechanical (solenoid) energy and change it if needed.
Automatic valve:
These valves do not need manual force or other energy sources to change the flow state. In other words, automatic valves change status according to the system requirements. The pressure relief valve is one of the types of automatic valves Classification of valve types based on connections One of the factors affecting the quality and efficiency of all types of valves is the connections used to install them in the piping system.
There are several ways to connect the valve to the pipe. Most of the valves are installed in the piping network using screw or fast connections, flanges, welding, silent welds, wafers and logs. Each of these connections is suitable for specific loads and operating conditions.
The image below shows some of the connections used for all types of valves Flanged connections in all types of valves Most of the valves are made by flange connections and installed in the piping system.
Installing and opening this type of connection is easier than other types. In order to ensure the proper sealing of the valve, a gasket is placed on the surface of the flange. The solids used in these solutions are metallic, nonmetallic or a combination of the two.
In general, flanged plates are larger than 15 mm and are made of bronze, iron and steel Screw or fasting connections in all types of valves
For the screw connection of all types of valves and piping systems, several threads are created on the end of the valve and pipe.
In this type of connections, sealing seams (on the threads) and gaskets (between the surfaces of the connections) are responsible for preventing fluid leakage. Plates with screw connections are usually used in pipe lines with a diameter of less than 150 mm.
These plates They are mostly made of bronze and in some cases made of iron and steel.Usually from the picture below, it shows a ball valve with a screw end Welded joints in all types of valves
Plates with welded connections are only used for steel pipes with a pipe size of 50 mm and above.
In order to implement welding connections, the end of the valve is machined so that it can be easily inserted into the pipe. After placement, welding is done around the joint.
This method is used for systems with high operating pressure and systems without the need to open the valve
Among the other connections used to install all types of valves in the piping network, the following can be mentioned:
Weld silent connection:
Suitable for low pressure systems Push connection:
Suitable for low pressure systems, copper pipes and steel pipes with a diameter of less than 65 mm.
Wafer connection and log:
Suitable for limited spaces, control valves and butterfly valves
One of the most important criteria for the classification of valve types is the type of disc and its mechanism of operation.
In the next section, we will give a complete introduction of each type of valve based on these criteria.
What is gate valve or sliding valve and how does it work?
Sliding valve, gate valve or "Gate Valve" is the most common type of valve in process factories. This valve, with its linear function, causes fluid to stop or pass through the piping system.
Sliding valves are fully open or fully closed. In other words, these valves are not used in fluid flow control.
The animation below shows how this type of valve works Mechanism of operation of sliding valve
According to the picture above, the gate valve uses a sliding disc (gates) or wedges as a blocking element.
The up and down movement of this disc causes the fluid flow path to open and close.
In order to achieve proper sealing of the flow path, in The entire surface of the disc must be in contact with the seat when the valve is fully closed.
These valves should not be used to control or regulate flow Sliding valve components According to the picture above, the valve gate components are:
Mehreh Falkh Falkh
The stem nut, the yoke nut, the place for lubricating the stem screw
nut
Gland flange
Gland or felt packing, back seat, lid, screws or studs, seals, lids, stoppers, barriers, seats, body, body
Types of sliding valves There are different criteria for dividing the types of sliding valves. These logs are divided into the following types based on the type of gate, cap connection and stem movement mechanism:
Types of sliding valves based on the type of gate or disc Sliding valve with solid conical wedge Sliding valve with flexible wedge Sliding valve with two-piece wedge Types of sliding valves based on body cap connection Screw cap, nail cap, welding cap, pressure cap Types of sliding valves based on the way the stem is moved Rising sliding valve (external stem and screw) non-rising sliding valve Advantages and disadvantages of sliding valve
The most important advantages of sliding boards are:
Providing a very good seal
Very low pressure drop during fluid passage
Can be used in both directions
Suitable for use in high temperature and pressure
Low maintenance requirements
Can be used for different types of fluids such as steam, oil, slurry and fluids with high viscosity
The following are the main limitations of sliding valves:
Inability to use to control fluid flow Low speed of opening and closing the path (although this feature is also considered as an advantage to reduce the possibility of damage to the valve) Making noise and vibration if it is incompletely opened It is difficult to repair the seat because of the limited access to the internal components
What is a ball valve or ball valve and how does it work?
The ball valve or "ball valve" is one of the types of rotary valve that uses a spherical (ball-shaped) barrier to stop or pass fluid in the piping system. Most of the ball boards are of fast action type and operate by turning 90 degrees at the handle. Valves connected to gas pipes inside buildings are usually ball valves. The moving picture below shows the functioning mechanism of these valves very well.
Mechanism of operation of ball valve
Opening and closing large ball valves requires considerable force. In these cases, rotary actuators are used to open and close the valve. Wing and valve components The different parts of a standard ball valve are shown in the figure below Ball valve component The sections indicated in the above image are:
the body
seat
Ball disc
Gasket or sealing washer
Screw or stud
nut
cover / body
Oring
Washer
Seal
Gland (a kind of felt tile used as waterproof insulation) Gland flange handle
screw
stem
Types of ball valves
There are different types of ball valves, they are divided into the following types based on the structure and direction of fluid flow:
Types of ball valves based on structure Sahrahi ball valve, floating ball valve, ball valve with axial installation Types of ball valves based on fluid flow direction Ball valve with top entry (one piece), ball valve with side entry (two pieces), three piece ball valve Advantages and disadvantages of ball valves The benefits of Bal Velo can be mentioned as follows:
Fast operation due to 90 degree rotation (suitable for quick stoppage of operation in case of necessity)
Minimizing leakage Smaller dimensions and lighter weight compared to sliding boards of the same category High flexibility in design and reducing the need for more valves Variety of dimensions and shapes
Safe operation at high operating pressure and temperature (if the quality of construction is high), better control with less force No need for lubrication Some of the limitations of ball valves are:
Lack of proper performance in situations requiring flow regulation
The possibility of accumulation of sediments of slurry fluids in the valve holes and increased wear of the valve.
Limitation of usable operating temperature range What is samouri milk and how does it work?
Samavari valve or "Plug Valve" is one of the types of valve with rotary movement system, it is usually used to control the flow of gas and liquid fluids. The blocking element in this type of valve is in the form of a cone or cylinder with It is the conduit for fluid passage.
The rotation of the cone and the alignment of its conduit along the pipeline route allows the movement of fluid flow in the system. The moving image below shows the structure and operation of one of the common types of check valves
The components of the Velo plug are:
handle (operator)
Grease-proof (fittings or connections used to enter lubricating materials) stem
Gland packing
packing
plug clamp
the body
Blocking element or plug (in closed state)
Duct or plug port (rectangular type)
Lubrication groove
All kinds of Velo Samavari
Samavari valves use cylindrical or conical discs to control fluid flow.
The types of Samari valves based on the structure and specifications of the port are:
Types of Samavari milk based on lubrication system
Samavari faucet with lubrication system Samavari faucet without lubrication system
Types of Samavari valves based on the shape of the disk port Samavari faucet with rectangular port
Samavari faucet with circular port Samavari faucet with rhombus-shaped port Types of Samavari valves based on the number of ports The plug is two ways, the plug is three ways, the plug is four ways Advantages and disadvantages of samovar milk Among the advantages of plug-in, the following can be mentioned:
Simple design with few parts High speed of opening and closing the fluid flow path
The possibility of performing repair and maintenance directly in the system Minimum resistance to current Providing a leak-free path Reducing the number of valves required in the system due to the possibility of designing multiple jets and changing the direction of the fluid flow Some of the limitations of samovar lions are:
The force required to open and close is high, due to high friction, it is not possible to use a manual operator for large valves.
Pressure drop caused by reducing the cross-section of the track High cost compared to ball valves with similar dimensions and class
What is piston valve or piston valve and how does it work?
A piston valve or "piston valve" is one of the types of linear valves used to control fluid flow.
This type is very useful
It is widely used in steam engines.
Piston valves are also used in gas and chemical fluid piping systems. These valves provide the possibility of stopping and starting the fluid flow according to the system condition. The function of the piston valve is similar to the spherical valve. With this difference, in this type, a piston is used instead of a spherical disk
What is a diaphragm valve and how does it work?
Diaphragm valve or "diaphragm valve" is one of the types of valve with linear movement mechanism and it is used to stop, start and regulate fluid flow. In the common type of this valve, it is made of a diaphragm (flexible disk).
The name of the flow blocking element and a raised surface on the bottom of the valve is used as the seat of the disc. Although the diaphragm is used in the piping of sanitary facilities, power plants, petrochemical plants, construction projects, mining projects and pharmaceutical factories. The following animation shows the general mechanism of this type.
It displays the valve Diaphragm valve components According to the picture above, the components of diaphragm valves are:
cap master bolt connecting the stem to the diaphragm In-diaphragm amplifier stem sheath
leg
Compressor
screw hole
The seal between the diaphragm and the body band or saddle (seat)
Fluid passage
Diaphragm movement channel
valve end connections (flange type) Diaphragm valve types
Based on the structure of the seat, diaphragm valves are divided into two main types: saddle or appendage and straight or smooth.
The picture below shows the difference between these two types of diaphragm valves. Straight diaphragm valves are usually used to control or regulate fluid flow.
The saddle type of these boards are a good choice for controlling the flow of abrasive and corrosive fluids
Advantages and disadvantages of diaphragm valve The following are the main advantages of diaphragm panels:
Complete blockage of flow, proper sealing and no leakage Easy maintenance and repair
No interference of repair operations with system performance
The following are some of the main limitations of diaphragm valves:
limited usable operating pressure (pressure around 21 bar) Limitation of usable operating temperature (temperature from -50 to 204 degrees Celsius) Mandatory use of corrosion-resistant body
The possibility of preventing complete drainage of the system (in the saddle type)
What is a butterfly valve and how does it work?
Butterfly valve or "Butterfly Valve" is another type of valve with a 90-degree rotation and control function. The rotational movement of circular or rectangular discs in this type of valve allows stopping, adjusting and starting the flow in systems.
Provides piping.The reason for the rotation of a valve actuator is the speed of flow adjustment using this valve. Butterfly valves are used in systems where there is no need to disconnect and connect the current.
These valves are used to control the flow of various gaseous, liquid and slurry fluids in various industries (even with high operating pressure and temperature)
Function mechanism of butterfly valve:
The actuator of the butterfly valve usually has a rib that connects the blade to the stem. This configuration reduces the required power and reduces the speed of current regulation. During installation, the valve must be in the open position. The closing of the propeller valve during the installation operation results in the seat being in front of the disk and difficult opening of the valve Butterfly valve components
According to the picture above, the main parts of the propeller valve are:
Flakhai actuator
rib cage
leg
the body
Disc
Seat
Types of butterfly valves
The types of butterfly valves based on the general structure and configuration of the stem are: Types of butterfly valves based on the structure Flanged butterfly valve
Wafer butterfly valve, log butterfly valve (around the hole), welded butterfly valve
Types of butterfly valves based on the difference between the disc axis and the stem axis
Butterfly valve without deviation (concentric) Butterfly valve with double deviation Butterfly valve with triple deviation
Advantages and disadvantages of butterfly valve
The following are the main advantages of butterfly valves: Occupying less space and less weight than other valve types
Low operating time
Keep the cost relatively low
Low pressure drop in the valve path
Can be used to pass chemical or corrosive fluids because it is equipped with a non-metallic seat
The following introduces some important limitations of the butterfly valve: Limited control and adjustment due to the low range of operating pressure difference and the opening of 30 to 80 degrees in the disc The possibility of cavitation and flow suffocation due to constant oscillation of the disc Poor sealing
What is a pinch valve and how does it work?
Throat valve or "pinch valve" is one of the types of valve with linear function, which consists of a flexible rubber duct. There is no equipment in the path of flow through the throat valve. However, the movement of two rods in Up and down the path, it provides the possibility to stop or start the flow completely. The pinch valve is a good choice for stopping, regulating and passing fluids with solid particles. For this reason, this valve is often used in the food industry, construction projects and pharmaceutical factories.
Components of throat milk Takes According to the picture above, the components of throat milk are:
Flakhai operator
Stem or axis
Lower disc
Upper disc
Rubber conduit
the body
Types of throat valves
The classification of types of throat valves is done according to different criteria as follows:
Types of throat valves based on body structure
Open throat valve
close throat milk
Types of throat valves based on the implementation mechanism Manual pneumatic hydraulic
Types of throat valves based on the type of sheath (current flow path) Standard two-layer sheath, conical sheath, variable sheath Advantages and disadvantages of throat milk The advantages of Pinch and Veloha are:
Suitable for abrasive and corrosive fluids
Low weight, small size and simple design
Minimal fuss and friction Providing a direct and unobstructed path for fluid flow No pollution Relatively fast mechanism Low construction and maintenance cost due to simple design The need for low maintenance and easy replacement of components The following points introduce the general limitations of throat milk types:
Not suitable for high operating pressure and temperature The possibility of damaging the rubber sheath or changing its shape in the high pressure difference is not suitable for vacuum systems Not suitable for turbulent flows Mechanism of action of ball valve The structure of spherical valves is very similar to the structure of sliding valves. However, due to the better contact angle between the cone or the sphere and the seat, the leakage of the spherical valves is less and their sealing is better. Globes and valves are usually used in systems that require complete sealing. Although this type is suitable for conditions where pressure drop is not an important issue.
Spherical valve components As we mentioned, the structure of the globe valve is very similar to sliding valves. The following picture shows the different components of this type of valve
The components of spherical valve are:
Mehre Falkh Flakh
leg yoke nut Master Bolt nut Gland flange Gland Insulation
Back seat
Master Bolt
nut
cap
Cap washer
the body
disc nut
Disc
Seat
Types of spherical valves
Spherical valve types are divided based on disc shape, body structure and body cover connections as follows:
Types of spherical valves based on disc Hub disc, needle disc, combined disc Types of spherical milk based on the body Ball valve z shape ball valve Y shape angular ball valve Types of ball valves based on cap connections
Screw cap Stud cap, welding cap, pressure or thermal cap Advantages and disadvantages of spherical milk
Due to the structural similarities of spherical valves and sliding valves, the characteristics of these two are usually compared to each other.
The following are the most important advantages of spherical valves:
Better blocking of the path than sliding doors Suitable for continuous opening and closing without worrying about the wear of the seat and disc. Easy repairs due to the access to the seat and disc from the top of the valve.
High execution speed compared to sliding valves due to the shorter length of the stem round trip ThemainlimitationsofGlob Thepossibilityofusinganautomaticoperator and Veloha are:
High pressure drop due to the existence of many obstacles in the path of fluid flow The possibility of damage to internal components in large and high- pressure lines due to disturbances and multiple impacts
The need for a lot of force to open and close large valves and making noise during use is more expensive than sliding valves.
What is a needle valve and how does it work?
Needle valve or "Needle Valve" is a type of industrial valve that controls, regulates or completely stops the fluid flow by using a needle barrier.
This type of valve is used to continuously regulate the flow in systems with Low flow rates are used. The design of needle valves is similar to the design of ball valves. All manual instrumentation in the piping system is installed with a needle valve.
By controlling the input flow, this valve prevents damage to precision ThecomponentsofNidel instrumentsduetoasuddenincreaseinpressure Velo are:
faucet handle
nut
cap
the body
seat
Handle screw
leg
packing
Oring
Types of needle valves
The types of needle valves are divided into the following according to the type of actuator and the direction of the stem in relation to the fluid flow:
Based on the type of operator
Manual needle valve, electric or pneumatic needle valve Based on the direction of obstruction
Linear needle valve, angular needle valve Advantages and disadvantages of needle valve
The main advantages of Nedel and Loha are:
The possibility of precise fluid control at very low flow intensity Not occupying much space due to small dimensions The possibility of adjusting the flow even at a low fluid flow rate Very high accuracy of flow rate adjustment Simple operation Among the limitations of needle valves, the following can be mentioned:
Pressure loss due to high ability to block fluid flow path Can only be used for lower rates The possibility of damage to the valve seat and needle if there are solid particles in the fluid composition Impossibility of opening or closing the valve immediately (damage to the valve components in case of rapid opening and closing)
What is a relief valve and how does it work?
Pressure Relief Valve" is one of the types of control valves used to drain the " fluid when the pressure increases too much and restore the system pressure to a safe level.
The main goal of using pressure relief valves is to increase the lifespan of equipment by preventing possible damage in critical conditions.
The animation below shows the mechanism of the relief function when excess Thereliefvalvemustbeabletofunctionproperlyand pressureoccurs correctly in all conditions and at every moment of the fluid transfer process in the system.
Therefore, the only source of energy needed to change the state in it is the energy resulting from the passage of the fluid. In other words, this type of actuator works automatically.
Valve relief components
In the picture below, different parts of one of the standard types of pressure relief valves are shown
The components of the pressure relief valve are:
hat Adjustment screw lock nut
The top plate of the spring cap
leg
spring
The lower plate of the spring closed
Split ring
gasket
Guide bush
pin
Ball
Disc
seat
the body
Types of pressure relief valves There are many types of pressure relief valves, the most common of which can be mentioned as follows:
Types of pressure relief equipment based on the closing mechanism Automatic manual Types of pressure relief equipment based on structure Typesofpressurereliefequipment Normal(spring)balancedpilotlantern Pressure relief vacuum breaker relief Pressure based on control parameters Advantages and disadvantages of pressure relief valve and vacuum breaker The most important advantages of the pressure relief valve are:
Can be used in all gas and liquid piping systems Suitable for use in high temperature and pressure Low cost compared to other valve types The limitations of the pressure relief valve include the following:
Negative effect of back pressure on valve performance The possibility of spring corrosion if corrosive fluids pass through the system Not suitable fo high risk systems In balanced discharge valves, the defects related to back pressure and the possibility of spring corrosion have been removed.
However, in these types of boards, there is a possibility of failure due to fatigue in the spring and the need for a separate washing system What is a one-way valve and how does it work?
One-way valves are types of non-return valves and are used to prevent fluid from moving against the specified flow path.
These valves provide the possibility of unobstructed fluid flow and closing the path if the pressure is low.
How to use one-sided boards depends on the mechanism of their types.
In general, one-way valves are a good choice for installation in fluid discharge systems such as pump and compressor paths.
The animation below shows the operation of one type of one-way valve The check components are:
the body
seat
Nut connecting the hinge to the disk, pin connecting the hinge to the washer disk
Disc
Hinge
Hinge connection pin with gasket body
cap
Nut for connecting the cover to the body, master bolt for connecting the cover to the body All kinds of even one-sided
One-sided lions are divided into different groups based on their structure and functioning.
Among the most common types, even on one side, the following :
can be mentioned
Oscillating check valve
One-way valve, hinged from above, angled one-way valve One-way pressure valve
One-way piston valve, one-way ball valve
One-way valve with two-piece disc One-way valve disconnecting advantages and disadvantages of one-way valve
Check valves are used in all cases to prevent fluid flow from returning. Therefore, their main advantage is their use.
Among the side advantages of the one-way valve, the following can be mentioned:
Maintain system pressure
Can be used as a backup system
Can be used in horizontal and vertical directions
The main limitations of one-sided valves are:
Impossibility of use in fluctuating and disturbed systems The possibility of increasing the rate of depreciation due to the sudden closing of the disk Despite the limitations of the check valve, this type of valve is considered the best option to prevent backflow in the piping system. Types of valves with special use In the previous sections, we introduced the most well-known and widely used types of valves used in piping systems. Some types of valves are designed and used for special applications.In this section, we briefly examine the use and structure of some special boards
What is a tubular valve or solenoid valve?
Solenoid valve is a type of control valve with an electromechanical actuator, which is used to block, start, measure, distribute or mix fluid flow.This type of valve has a high operating speed, It has good reliability, long life, compatibility with all kinds of materials, low energy consumption and small dimensions. Solenoid valves are used in fluid flow control of cylinders, hydraulic motors or Large industrial valves are used.
Many mechanized irrigation systems also use these trees. The following picture shows the different components of this type of valve
1) Coil
2) Armature 3) Shaded pole 4) Spring
5) Plunger
6) Seal
7) Body
When the electric current passes through the solenoid valve, a magnetic field is created around the coil. This field causes the plunger to move towards blocking the flow path. In fact, the solenoid valve converts the electrical energy into the mechanical energy needed to control and regulate the flow
What is reducing valve or reducing valve?
The pressure reducing valve or "Reducing Valve" is one of the types of valve with hydraulic actuator and diaphragm disc, which is used to reduce the pressure of the upstream flow and transfer the flow with lower pressure to the downstream. In fact, this type of valve , by removing disturbances and pressure fluctuations in the upstream, it causes continuity and stability of the pressure in the downstream of the system.
The disk reducing valve is usually in the open state. This type of valve is used in air compressors, aerospace equipment, gas cutting and welding, pressure reactors, mining equipment and City water pipes can be used
What is a floater?
The float valve, "Float Valve" or floater, is a type of control and isolation valve with a special operator, which is used to check the amount of fluid and stop the flow.
The most well-known type of float valve is the floater used in water coolers. Of course, floating valves are used in water tanks, refrigeration plants, building sanitary facilities and industrial plumbing systems (among other types of valves).
Despite the variety of industries and places where they can be used, the mechanism of operation of most floaters is similar.
The animation below shows how the floating valve works
What is a fixed cone valve?
Fixed Cone Valve" (Fixed Cone Valve) is one of the types of valve with linear " movement and control function, it is often used as a turbine auxiliary valve, reservoir emptying valve (especially dam reservoirs) or continuous flow control valve.
If the fluid pressure increases, the cone embedded in the center of this valve is guided to the outside.
This mechanism provides the possibility of emptying the fluid from around the cone and adjusting the pressure of the system upstream of the valve
What is multi-way milk?
The multi-way valve or "Multiport Valve" is one of the types of valves with a special use, where the flow blocking element consists of several channels or so-called ports.
Several usage modes are defined on the operator of these valves. Changing the state of the operator and placing it on each state determines the direction of the fluid flow.
In this way, it is possible to enjoy several functions using one valve By placing the operator of this valve on different positions, it is possible Direct the water passing through the piping system towards the filter (purification) or the sewer (empty). Other situations allow the possibility of closing the path, reversing the flow, bypassing the filter path and many other capabilities.
What is a valve manifold?
The manifold valve or "manifold valve" is a tool consisting of several valves, which is used to change or calibrate the pressure transmitter in the piping system (without the need to stop the flow transfer process).
There are three main types of manifold valves. They are divided into one way, three ways and five ways. Opening and closing the path of different valves in these valves allows checking the system performance and calibration of the instruments.