The working principle of various valves

Valve structure principle
The sealing performance of the valve refers to the ability of each sealing part of the valve to prevent the leakage of the medium, which is the most important technical performance index of the valve. There are three sealing parts of the valve: the contact between the opening and closing parts and the two sealing surfaces of the valve seat; the cooperation between the packing and the valve stem and the stuffing box; the connection between the valve body and the valve cover. The leakage in the former part is called internal leakage, which is commonly referred to as lax closure, which will affect the ability of the valve to cut off the medium. For shut-off valves, internal leakage is not allowed. The leakage in the latter two places is called external leakage, that is, the medium leaks from the inside of the valve to the outside of the valve. External leakage will cause material loss, pollute the environment, and even cause accidents in severe cases. For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the valve must have reliable sealing performance.

Valve Classification Catalog
1. The opening and closing part of the Brass Ball Valve FNPT is a sphere, which is driven by the valve stem and rotates 90° around the axis of the ball valve to open or close. It can also be used for fluid regulation and control. It is mainly used for cutting, distributing and changing the flow direction of the medium in the pipeline. It has good sealing performance, convenient operation, rapid opening and closing, simple structure, small volume, low resistance, light weight, etc. Features.
2. The opening and closing part of the gate valve is the gate. The movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. It is mainly used to cut off the medium in the pipeline. It can flow in any direction on both sides. It is easy to install, easy to operate, smooth in the channel, small in flow resistance and simple in structure.

3. The opening and closing part of the butterfly valve is a butterfly plate, which is driven by the valve stem and rotates 90° around its own axis in the valve body, so as to achieve the purpose of opening and closing or adjustment. It is mainly used to cut off the medium in the pipeline. It has the characteristics of simple structure, flexible operation, rapid switching, small size, short structure, low resistance and light weight.

4. Globe valve opening and closing parts are plug-shaped valve discs. The sealing surface is flat or conical. The valve disc moves linearly along the center line of the valve seat to achieve opening and closing. The globe valve can only be fully opened and closed. All closed, can not be adjusted and throttled. It is mainly used to cut off the medium in the pipeline. It has the characteristics of simple structure, easy installation, convenient operation, smooth passage, small flow resistance and simple structure.

5. Check valve refers to the valve that automatically opens and closes the valve flap by relying on the flow of the medium itself to prevent the backflow of the medium, also known as check valve, one-way valve, reverse flow valve, and back pressure valve. The check valve is an automatic valve whose main function is to prevent the backflow of the medium, the reverse rotation of the pump and the driving motor, and the discharge of the medium in the container.

6. Control valve, also known as control valve, in the field of industrial automation process control, by accepting the control signal output by the adjustment control unit, with the help of power operation to change the final process parameters such as medium flow, pressure, temperature, liquid level, etc. control element. It is generally composed of actuators and valves, which can be divided into pneumatic control valves, electric control valves, and self-operated control valves.

7. Solenoid Valve is used in combination with electromagnetic coil and straight-through or multi-way valve. It can be divided into two types: normally open and normally closed. It is used to control the switch or switch the flow direction of the medium through AC220V or DC24 power supply, which is the basis for automation of fluid control. The selection of components and solenoid valves should first follow the four principles of safety, reliability, applicability and economy.

8. The opening and closing parts of the safety valve are in a normally closed state under the action of external force. When the pressure of the medium in the equipment or pipeline rises above the specified value, the medium pressure in the pipeline or equipment is prevented by discharging the medium to the outside of the system to prevent the pressure of the medium in the pipeline or equipment from exceeding the specified value. Special valve with specified value. Safety valves belong to the automatic valve category and are mainly used for important protection in boilers, pressure vessels and pipelines.

9. Needle valve is an important part of the instrument measurement pipeline system. It is a valve that can accurately adjust and cut off the fluid. The valve core is a very sharp cone, which is generally used for small flow. High pressure gas or liquid, the structure is similar to the globe valve, and its function is to open or cut off the pipeline passage.

10. Trap Valve (Trap Valve), also known as trap, also known as drain valve, is an energy-saving product that discharges condensed water, air and carbon dioxide gas in the steam system as soon as possible. Choosing a suitable trap can make the steam heating equipment achieve the highest working efficiency. In order to achieve the best effect, it is necessary to have a comprehensive understanding of the working performance and characteristics of various types of traps.

11. The plug valve (Plug Valve) opening and closing part is a plug body. By rotating 90 degrees, the channel port on the valve plug is connected or separated from the channel port on the valve body to realize the opening or closing of a valve. The shape of the valve plug can be cylindrical or conical. In a cylindrical valve plug, the passage is generally rectangular, while in a conical valve plug, the passage is trapezoidal. Suitable for switching off and on medium and for diverting applications.

12. Diaphragm Valve is a globe valve that uses a diaphragm as an opening and closing member to close the flow channel, cut off the fluid, and separate the inner cavity of the valve body from the inner cavity of the valve cover. It is a special form of shut-off valve. Its opening and closing part is a diaphragm made of soft material, which separates the inner cavity of the valve body from the inner cavity of the valve cover and the driving parts. It is now widely used in various fields. Commonly used diaphragm valves include rubber-lined diaphragm valves, fluorine-lined diaphragm valves, unlined diaphragm valves, and plastic diaphragm valves.

13. Discharge Valve is mainly used for bottom discharge, discharge, sampling and no dead zone shut-off operation of reactors, storage tanks and other containers. The bottom flange of the valve is welded to the bottom of the storage tank and other containers, thus eliminating the residual phenomenon of the process medium usually at the outlet of the valve. According to the actual needs of the discharge valve, the discharge structure is designed to work in two ways: lifting and lowering.

14. The Exhaust Valve is used in the fluid pipeline system as an exhaust function. During the water delivery process, the air is continuously released in the water to form an air bag, which makes it difficult to deliver water. When the gas overflows, the gas will climb up the pipe and finally gather at the highest point of the system. At this time, the exhaust valve starts to work and exhaust through the floating ball lever principle.

15. Breathing Valve is a safe and energy-saving product used to balance the air pressure of the storage tank and reduce the volatilization of the medium. The principle is to use the weight of the positive and negative pressure valve disc to control the positive exhaust pressure and negative suction pressure of the storage tank; The pressure in the tank will not continue to drop or rise, so that the air pressure inside and outside the tank is balanced, which is a safety device to protect the storage tank.

16. Filter Valve is an indispensable device on the conveying medium pipeline. When there are too many impurities in the medium, which will affect the operation of the equipment, the mesh size of the filter screen is selected according to the thickness of the impurities. The net filters out impurities to ensure the normal operation of the rear equipment. When cleaning is required, just take out the detachable filter cartridge and reinsert it after cleaning. Therefore, it is extremely convenient to use and maintain.

17. Flame Arrester is a safety device used to prevent the spread of flames of flammable gases and flammable liquid vapors. Generally installed in the pipeline for transporting flammable gas or on the ventilated tank, the device that prevents the propagation of flame (deflagration or detonation) from passing through is composed of flame arrester core, flame arrester shell and accessories.

18. Angle valve F1960PEX x Compression Straight is widely used in short-time frequent start-up. It has the characteristics of sensitive response and accurate action. When used with solenoid valve, the gas and liquid flow can be accurately controlled by pneumatic control. Accurate temperature control, dripping liquid and other requirements can be achieved. Mainly used in automation industry to control fluid water, oil, air, steam, liquid, gas, etc. The advantages of safe use, maintenance-free and long life.
19. Balance Valve (Balance Valve) There is a large pressure difference or flow difference in each part of the pipeline or container. In order to reduce or balance the difference, a balance valve is installed between the corresponding pipelines or containers to adjust The relative balance of pressure on both sides, or the balance of flow through the method of diversion, is a special function of the valve.

20. The blowdown valve is evolved from the gate. It uses the gear to rotate 90 degrees to drive the valve stem to lift to achieve the purpose of opening and closing. The sewage valve is not only simple in structure and good in sealing performance, but also small in size, light in weight, low in material consumption, small in installation size, especially small in driving torque, easy to operate, and easy to open and close quickly.

21. Sludge Discharge Valve is an angle type globe valve with hydraulic source or pneumatic source as the actuator. It is usually installed in rows on the outer wall of the bottom of the sedimentation tank to remove the sediment and dirt at the bottom of the tank. Equipped with manual square valve or solenoid valve, the mud valve switch can be controlled remotely.

22. Cut-off valve is a kind of actuator in automation system, which is composed of multi-spring pneumatic membrane actuator or floating piston actuator and regulating valve. Receive the signal of the regulating instrument, and control the cut-off, connection or switching of the fluid in the process pipeline. It has the characteristics of simple structure, sensitive response and reliable action.

23. The reducing valve is a valve that reduces the inlet pressure to a certain required outlet pressure through adjustment, and relies on the energy of the medium itself to keep the outlet pressure automatically stable. From the point of view of fluid mechanics, the pressure reducing valve is a throttling element whose local resistance can be changed, that is, by changing the throttling area, the flow rate and the kinetic energy of the fluid are changed, resulting in different pressure losses, so as to achieve the purpose of decompression.

24. Pinch valve, also known as pinch valve, air bag valve, hoop break valve, is composed of upper and lower cast iron, aluminum alloy, stainless steel valve body, rubber tube sleeve, large and small valve stem gate, upper and lower guide posts and other parts. When the handwheel is turned clockwise, the large and small valve stems simultaneously drive the upper and lower stubble plates, compress the sleeve, and close, and vice versa.

25. Plunger Valve (Plunger Valve) Plunger valve is composed of valve body, valve cover, valve stem, plunger, hole frame, sealing ring, hand wheel and other parts. The valve rod drives the plunger to reciprocate up and down in the middle of the hole frame. Movement to complete the opening and closing functions of the valve. The sealing ring adopts a new type of non-toxic sealing material with strong elasticity and high wear resistance, so the sealing is reliable and durable. Thus, the service life of the plunger valve is increased.

26. Bottom Valve consists of valve body, valve disc, piston rod, valve cover, positioning column and other parts. See the figure below for details. Before starting the pump, fill the suction pipe with liquid, so that the pump has enough suction, suck the liquid into the valve, open the piston valve flap, so as to carry out the water supply operation. When the pump is stopped, the valve flap is closed under the action of hydraulic pressure and its own gravity. , while preventing the liquid from returning to the front of the pump.

27. The sight glass is one of the main accessories on the industrial pipeline device. In the pipeline of the petroleum, chemical, pharmaceutical, food and other industrial production equipment, the sight glass can observe the flow and reaction of the liquid, gas, steam and other media in the pipeline at any time. To monitor production and avoid accidents in the production process.

28. Flange is also called flange flange or flange. Flanges are the interconnected parts between shafts and are used for the connection between pipe ends; they are also used for flanges on the inlet and outlet of equipment for the connection between two equipment.

29. The hydraulic control valve is a valve that opens, closes and adjusts the pressure of the pipeline medium as the driving force. It consists of a main valve and attached conduits, needle valves, ball valves and pressure gauges, etc. According to the purpose of use and different functional places, it can be evolved into a remote control float valve, pressure reducing valve, slow closing check valve, flow controller. , pressure relief valve, hydraulic electric control valve, emergency shut-off valve, etc.

Post time: Feb-21-2023