Valve

The valve is a device used to control flow and pressure of fluids. The main tasks of the industrial valves are:
1) Completely disconnect the current
2) Prevent the flow of liquids and gases
3) Adjust the passage of the required amount of liquids and gases
4) Adjust and control the amount and pressure of liquids and gases
5) Control and keep the devices under pressure
And basically, the valves are used in cases where there is a pressure difference between the fluid flow (liquid and gas).
History
The first valve that was invented by humans is what we now know as the (valve) valve. The valve that opened or opened the stream by placing or removing it in the waterway. The gates of today's gates are in fact the same old gutters.
Sex and material
According to the application, the materials used to make the valve are different. In construction, cast iron, bronze, brass, and sometimes stainless steel (SS) valves are used. In industrial works such as power plants, petrochemical plants, refineries, shipbuilding and pharmaceutical / food industries, depending on the fluid passing through the valve or the environment where the valve is located, the body and other components are made of carbon steel, alloy steel, Stainless Steel. The valves are opened or closed by the hand or the actuator.
Important points in the design and construction of valves are:
1. Startup power and special equipment
2. Vibration of the valve
3- Cavitation
4. Effect on the flow
5. The amount of pressure bearing
6. Sealing and consuming materials in the sections
7. Ease of maintenance and maintenance of their installation
8. Pools of tranquility
Different types of valves
1) Manual operated valves manually operated
2) Automatic valves operated by air, fluids and controlled gases
3) Automatic valves that work with power. Electric motor operated valves
The labs that are discussed here are:
1) Needle valves needle valves
2) Sample valves plug or clock valves
3) Globe valves spherical valves
4) Angle valve ANGLE VALVE
5) BALL VALVE
6) Gate valves sliding valves
7) Diaphragm valves diaphragm valves
8) BAKE WATER VALVE BACK WASHER BACK
9) PRESSURE REDUCING VALVE
10) One-way valves non return or check valves
11) butterfly valve valves
12) Safety valves
13) Drain valve
14) CROSS GLOBEVALVE three-way valve
15) ANGLE VALVE ANGLE LINE
16) HOSE VALVE HOSE
17) WATER GAUGE VALVE
18) Special valves SPECIAL PURPOSE VALVES
19) Automatic control valves
20) BALANCING VALVES balancing valves
21) Pressure relief valves PRESSURE RELIEF VALVES
1) Needle valves needle valves
The needle valve, which has the name of the disk and its seat, is a family of spherical valves in terms of its construction and workmanship. With these valves, it is possible to accurately control the flow of fluid, especially in thin, thin pipes. The structure of this valve is such that the flow is directed to a small hole, and after turning 90 °, it is guided to the tip of a cone, and as the flow figure shows, the flow flows through this hole and a needle-shaped piece to the outlet ... this disc The type of valve consists of a thin conical bar that passes through the circular hole and limits the fluid flow. The building of these valves is used more in carburetors. This type of valve is very elegant and almost small in terms of its construction and is used in sensitive and precise operations due to its reliable mechanism. In petroleum or petrochemical laboratories and instruments, it is very much used. The diameter of the needle valves usually does not exceed 2 inches, and the needle needles are used more often in places where the limitation is necessary, and the limitation is the delay time and the gentle pressure change.
2) Sample valves plug or clock valves
These valves are designed for low currents and are made of triple gauge: piston valves of this type. This type of valves consists of a bar in between which is provided for the flow of water and is located between a container that is internally machined and poured. These valves, like the valve, provide very little resistance to water flow. To open and close the samovar valve, it's just enough to handle it as much as 90 degrees ... Usually these valves are used as a dual-mode control (disconnect / unplug) because they are (1) relatively inexpensive, (2) when They remain in the same position; and (3) employees can see the open or closed status clearly. If the orifice surface area is equal to the area of ​​the pipe section, the valve yield as a flow controller will be reduced.
3) Globe valves
This valve has a spherical name from its body shape, which is spherical, and its internal structure is such that the fluid changes from the entry point to the valve to its 180 ° exit. The building of the valve and its seat is such that once the flow of their contacts is interrupted. Also, the absence of complete valve spheres does not cause fatigue. Therefore, it can be used to adjust the flow. The fitting of the valve handle's number with the volume of the liquid outlet duct makes it easy to adjust the amount of flow with the hand.
Specifications for spherical valves include:
The fluid flow changes in contrast to the sliding valve.
Changing the direction of the fluid flow creates turbulence.
The turbulence increases the pressure drop.
In the spherical valve, the pressure drop is greater than the drop valve.
In the spherical valve, as soon as the connector is disconnected, the end of the stem and the seat of the fluid are completely flowing
In the spherical valve, the burnout is much less than the sliding valve due to friction.
One of the varieties of spherical tapered spherical tap water is the change in the direction of the fluid less than ordinary spherical valve, and the turbulence of the fluid in an angular spherical valve is less than that of a typical spherical valve. Finally, in the case of spherical valves, this type of valve is designed to control the fluid, and due to a sudden change in the fluid path, opening and closing the valve is done much faster. It should also be noted that the various materials used in their construction are available; and their repairs are less and less convenient than sliding valves, so that repairing them without removing them from the piping route is possible and the valve often comes from nickel or Stainless steel.
4) Angle valve ANGLE VALVE
This type of valve is the same as the spherical valve, with the difference that there is a 90 ° angle between the inlet and the outlet. This type of valve produces less pressure than the spherical valve, and also due to its special shape, the use of plumbing fittings and it also saves the time it takes to install.
5) BALL VALVE
These valves are also called blows. The flow of water in these types of valves passes through the hole of a spherical ball in a perfectly polished spherical position. To open and close these types of valves, just like the samovar valves, it is enough to rotate 90 degrees of its handle. These valves also offer a slight resistance to water flow. These types of valves can be used in hot and cold water pipes as well as low pressure gas piping.
6) Gate valves sliding valves
These valves are used more often in places where they want to completely open or close the flow of fluid. The properties of these valves are the result of low pressure drop across the lids, which is why they are used for long pipes from these valves. When the drawer is directed to the top and is removed from the flow of fluid and thus has no resistance to flow, but if the drawer is directed to its lowest point, then the fluid is due to a change of direction and collision with the drain creates turbulence and a pressure drop. In plumbing, pipes and valves are often joined (by welding or by screw), but in general, the connection of the valve and the tube is done by the flange and the bolts and nuts, and to prevent the leakage between the flange pipe, the sealing valve or gasket is inserted.
Stem building
The rod is a slender bar that is connected to the hand wheel on one side and the gate to the other. The stick attached to the drawer of the valve passes through a stuffing box.
There are two types of gate valve:
1) The first type, known as parallel, is based on the use of a bed of a door located between two parallel chambers. (Upstream and downstream). These Volos also have a sharp edge in their lower parts, which is a sharp edge for cutting and removing solid particles entering the volcano. An important advantage of these types of valves is that these valves can be used for angled valve seats, in addition to being used for asymmetric valve seats.
 2) Other types of gate valves are gate valves with gate shapes. In this type of valves, two diagonal and diagonal valves are used. (In order to be closed in shut-off mode)
As we know, the stem draws the drawer up and down and thus controls the amount of valve opening and closing. Let's not forget that the sliding valve is completely straightforward to move the fluid, and if the valve is completely open, the drain will flow out of the flow path and the drop of the fuser will be minimized, as well as a very low flow of turbulence.
7) Diaphragm valves diaphragm valves
The valve has a curtain or diaphragm of a simple and interesting building. This type of valve consists of three major parts: the body, the diaphragm and the cap net,
The diaphragm is made of reinforced rubber curtains or other elastic material, which moves and moves the elastic luminaire and controls the flow of fluid through a small amount of fluid, thereby controlling the amount of fluid. The diaphragm separates the valve content from its open and close mechanism, so it does not need sealing devices. If the material comes out of the valve, the hole of the curtain is to be replaced, which should be replaced. This type of valve is used to control corrosive substances, such as acids. It should be noted that the use of a diaphragm valve is useless when the temperature is high, as it is melting at a high temperature of the diaphragm. The diaphragm can be made of heat-resistant plastic materials but not economical. These types of valves have good closure properties, so that in a closed state, no flow of fluid passes through it. This type of valve is used in low pressure and low temperatures.
Diaphragm valves are divided into two groups based on body shape:
1) Type with inside body (weir type)
In this type, a bulge in the body is embedded in casting. When the Volvo closes, the aperture sits on this bulge and restricts the flow of flow.
2) Type without a straight-through type
In this type of flashing, the diaphragm becomes one of the shapes. Diaphragm valves can also be used to control the flow. The type (weir with a barrier protrusion in the middle) is an appropriate option for controlling flow, but its disadvantage is the limitation of the fluid passageway. Diaphragm valves can also be used to control small currents when the fluid is corrosive and radioactive. The shelf life of the diaphragm depends on the type of material that passes through the tubing, as well as the temperature, pressure and the frequency of use of the vulva. In some types of elastomeric diaphragms, these diaphragms have excellent resistance at very high temperatures. However, it should be noted that the mechanical properties of elastomeric materials will be lowered at high temperatures and can be lost at high pressures. Most elastomeric materials have the best performance at temperatures below 150 F. Of the other things, the benefits of these volvops are the isolation of different parts of the valve vs. fluid flow. In such a way that the diaphragm itself is able to isolate different parts of the valve even if it passes through the fluid.
Due to these properties, these volatiles will be suitable for corrosive fluids as well as fluids containing suspended solids ... Due to the fact that the cap assembly, even if it is not exposed to contact with the fluid, can be used to make materials cheaper. . Given the advances made in the diaphragm design and its materials, today's new diaphragms are capable of operating with a variety of fluids. 8) BAKE WATER VALVE BACKWASH VALVE This type of valve is used only in the sewage piping, and it works like a one-way valve. In cases where different sewage systems return to the wastewater inlets of the building, these valves will prevent this operation. These types of valves are usually installed in areas such as underground buildings that have a low altitude to the sewage disposal area to prevent sewage returns. 9. Pressure relief valve. PRESSURE REDUCING VALVE. Pressure regulator valve or pressure regulator valve, normally close. The water meter of the buildings is installed after splitting from the city's main water pipe to reduce the pressure and city pressure pressures. This valve can be called an all-in-one device because it has a special construction to carry out changes and reductions of pressure, which does this without energy transfer. These valves have a pressure adjustment knob that adjusts the pressure output pressure. As shown in the figure, a trash can or a filter must be connected to the pressure shaft valve so that the outer material does not damage the internal mechanism of the valve.
10) One-way valves non return or check valves
One-way valves are transmitted to prevent the return of liquid or gas that is sent. The reasons for using them in the industry and household appliances are as follows.
A: In homes: On the water supply, put the water to the side of the building, which in the event of a water jet, the amount of water stored in household appliances and inside pipes is not returned to the main pipe.
B- On the inlet pipe of the water heaters, which should not be left empty due to the cutting of water or the breakage of the pipe inside the building's water stored in the water tank because the furnace may continue to work and cause the heating water to burn.
(C) In the refineries, the unilateral valve is pumped to the outlet pipe, which cannot return after transferring the required amount of oil and closing the pump or shutting down the pumping material. Because of the return, in addition to the waste of energy consumed to send it, it may the receiver side of the material also encounters an immediate shortage. More important, the return pressure of the returning fluid that is reversed from the same path may cause the centrifugal pump to rotate at an increasing speed, and the speed so high that the pump is hotter to fail. And even explode.
They work in such a way as to raise the pressure of the valve or valve of the valve and cause liquid or gas to pass, until the pressure below the valve is greater than the pressure on it, the valve remains open and the liquid or gas passage will continue if for any reason Pressure below the valve is less than the pressure on it. The weight of the valves and the pressure of the materials that are going to return will cause the valve to close and prevent the material from returning.
11) butterfly valve valves
One of the simplest valves that is commonly used in oil and petrochemical plants. Their buildings consist of a regular body and a circular plate, which is located in the middle. This page is about 90 degrees around the bars and is connected by lever to the movable valve. This actuator can be manually or by air pressure or electricity.
Small pro control gates make up 4 inches to 24 inches. Their repairs are simple, but they should be regularly flushed. Some of them are specially equipped with a handgun that is attached to the plate rod and its mechanism is located in a gear box. As long as the main actuator, which is air or hydraulic, cannot be restrained by releasing it from the gear with a lever or gateway in any position. The use of valves in units with low pressure during operation is very common because of the minimum pressure drop and industrial designers are, as far as possible, trying to prevent pressure drop in systems because otherwise they are in terms of cost their installation is not cost-effective. The other feature of these valves is to maximize the flow speed of the fluid in the minimum time and movement of the valve, especially for controlling the pressure of the fluid in the pressure vessels or towers, and also these types of valves are used in a large volume of fluid transfer. Due to the light weight and low cost of the price, there is a serious cooperation between the designers of the valves and experts in the field of metallurgy and plastic and rubber industries, which makes the plate of the disc and the seat in a variety of lightweight and elastic. The importance and reputation of the anchor valve are as follows: easy to use, lack of sliding and sliding parts, reduced pressure drop, control ability, cheapness and lightness, the non-combining of the made-up profile with cross-products such as chemical or petrochemical
The use of valves includes:
Thermal Power Station, Hydroelectric Power Station, Oil and Gas Industries, Water and Sewage Plumbing
12) Safety valves
Compressors and boilers, turbines, hollow vessels, and other pressurized installations, which contain gas or liquids, are often subject to a high, but controlled, pressure. Sometimes it's possible that the controller does not perform properly and does not perform its task properly, causing excessive pressure on the machines to rise. This can be damaged, corrupted and result in significant personal and financial losses. In order to prevent such incidents, in addition to controlling devices, another device called a safety valve is installed on pressurized devices; if the pressure is exceeded, the pressure is automatically opened and, by removing some of the contents of the device, pressure it down to the lower limit they bring.
Safety valves are used only for gases, air, steam, etc. (excluding liquid). These valves automatically prevent unplanned pressure increase on pressure vessels and plumbing systems. These valves also have a certificate that must be checked before use. The safety valve automatically prevents the pressure from increasing the pressure of the previously set gas. In other words, if required, the required amount of gas, water vapor or air is drained to allow the pressure of the device to reach the required size. The safety valve should choose to release the container's pressure balance (about 10% more than the pressure that the container should normally hold or at the highest pressure the container can handle). The safety valve is opened and the quantities of liquid or gas removed. He does. The valve level of the safety valve should be equal to or above the level of the valve inlet of the container or reservoir. The safety valves are chosen so that they must be opened not only at a certain pressure, but their capacity must be such that large amounts of liquid or gaseous contents are changed due to heat (evaporation of liquids or expansion of gases).
These valves are characterized by three types: the lids that are installed on the sources of containers and gas contents devices called safety valve. Bridges that are installed on liquid sources and devices are referred to as relief valves. Insulated gas and liquid sources and devices are called safety relief valve. Truncates are divided into three types: - Laminates with springs: These valves are the best protector for pressure vessels, fitted with a suitable spring on the valve plate. And on top of the seal is the pressure by which the pressure on the tank pressure valve in the level of safety. 2. Valve valves: These valves are valves that restrain the weight of the cylinders on the pressure valve inside the reservoir to an acceptable level of safety. 3. Truncheons with springs and diagrams: for control Materials and fluids are used in containers of these types of valves because they can control the pressure and the level of fluid in a container or reservoir. It should be ensured that the certified capacity of the safe valve is correct to obtain the valve capacity; it is tested with saturated air or steam, or natural gas. 13) Evacuated drain valve that is embedded in steam boilers and at the lowest the part of the boiler is installed and, if necessary, depletes the sediment and the mass and other impurities that are deposited. 14) Three-way valve of the CROSS GLOBE VALVE. The aim of the application of these types of valves is to control the flow temperature of the three-way valve Mixer. This valve always connects two ways. This valve can be installed in a main path and the third side is connected to a branch and can be adjusted to allow the cross-flow of water to branch. The performance of the mixing and splitting triple valves is different. In the three-way mixer valves, the two streams are mixed together and create a common flow. While in the triple divider valves or flow paths, a flow of fluid is divided into two parts to control the temperature. In some workings (egg control of the cooling tower), instead of the mixing valve, use a tap or split valve. 16) HOSE VALVE HOSE VALVE These valves are used to irrigate the garden and green space, 1,4 / 3 and 1 inch 17) WATER GAUGE VALVE This valve is used in glass water vents to cut water and water connection.
18) Special valves SPECIAL PURPOSE VALVES
In some workings, special valves are used, for example, four ways to circulate water in the boiler ring. A type of four-way valve is also used as the valve for converting the status of the cooling system. Using the type of valve in the heat pump systems, the evaporator role is replaced with a condenser. Floating valves are another type of special valve that is used to feed water into a tank with a source or, in specific cases, as a feed valve for the boiler.
19) Automatic control valves
Automatic valves are usually the valves used in conjunction with a controller to control the flow rate. The control valves are divided into the following groups: a. ACTUATOR TYPES type: A signal operator converts the output signal from the controller (egg, an electrical signal or wind) to a linear or rotational motion. Operators have different sizes, types, outputs and controllers. The most commonly used operators for self-operating valves are: SOLENOID, PNEUMATIC, ELECTRICAL, And ELECTRONIC, HYDRAULIC AND THERMOSTATIC MOTORS. Two-way (one and two seating) TWO-WAY SINGLE ANDDOUBLE-SEAT: In automatic valves, two lines of fluid will enter the opening and exit the outlet. Due to the position of the valve stem (STEM) and the disc valve (DISK), full flow or less flow can pass through the valve. Two-way valves can have one or two ducts. In the case of valve seats, a latch and a disk are used to close the valve. Double decker lounges are a special type of two-way valves with two seats and two discs. These valves are used in cases where the amount of drop in pressure during the closure of the valve is too much of the laced dish. C) THREE-WAY VALVES: In MIXING triple valves, two streams are mixed together. Commonly used in HVAC systems, these valves are used to mix water coolers or water heaters. The use of these valves controls the temperature of the air after
 
Water cooled coils. For this purpose, the cooling water is fed to the coil, with the warmer water coming back from the mixing coil. The same can be done for a water heater. D) BUTTERFLY VALVES: In some applications, these valves cannot be used due to the limitation of the size or the size of the mixing and splitting triple valves. In such cases, two valves that are mounted on a three-way and connected by levitation will be used. It should be noted that the flow characteristics of the valves are different from those of the standard valves with disc and seating, so the use of these valves is only possible in those cases where their flow characteristics are responsive.
20) Balancing valves
 BALANCING VALVES
Hand-balancing valves can be ROTARY, RISING, or NON-RISING. Generally, the valves' building has a porch with a stomp that adjusts its position with respect to the compressive forces, thus changing the flow area. With this valve, when the amount of pressure drop is changed, the amount of fluid flow will reach a predetermined value.
21) Pressure relief valves
PRESSURE RELIEF VALVES
Typically, valve terminals and pressure relief valves are used interchangeably. The shape and the work done in both types of valve are the same, limiting the amount of pressure of a liquid, steam or gas by discharging part of that fluid. The valves are usually used for air and steam. The characteristic of these valves is their quick opening and closing. Pressure relief valves are generally used for liquids and are either open or closed at high or low pressure and slowly.