Valve is a device used by Gongliang to control the direction, pressure and flow of fluid in the fluid system. A valve is a device that allows the flow or suspension of the medium (liquid, gas, powder) in the piping and equipment, and can control its flow.
The valve is a control component in the pipeline fluid transportation system, which is used to change the channel section and the flow direction of the medium, and has the functions of diversion, cut-off, saving, check, diversion or overflow pressure relief. Valves for fluid control, from the simplest globe valves to the most complex automatic control systems used in various valves, have a wide variety of varieties and specifications, and the nominal diameter of valves ranges from very small surface valves to industrial pipeline valves with a diameter of up to 10m. The valve can be used to control the flow of various types of fluids such as water, steam, oil, gas, mud, various corrosive media, liquid metal and radioactive fluid, the working pressure of the valve can be from 0.0013MPa to 1000MPa ultra-high pressure, and the working temperature is from -270°C ultra-low temperature to 1430°C high temperature. The control of the valve can adopt a variety of transmission modes, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electrohydraulic, pneumatic, spur gear, bevel gear drive, etc.; Under the effect of pressure, temperature or other forms of sensing signals, it can act according to the predetermined requirements, or simply open or close without relying on the sensing signal, and the valve relies on the drive or active organization to make the opening and closing parts lift, slide, swing or slew movement, so as to change the size of its flow channel area to achieve its control function
By effect and usefulness
(1) Cut-off: such as gate valves, globe valves, plug valves, ball valves, butterfly valves, needle valves, diaphragm valves, etc. The shut-off valve, also known as the closed circuit valve and the globe valve, has the effect of connecting or cutting off the medium in the pipeline.
Check valve, check valve is also known as check valve or check valve, check valve is classified as an active valve, its effect is to avoid the backflow of the medium in the pipeline, avoid the rotation of the pump and the drive motor, and the leakage of the container medium. The foot valve of the suction off of the water pump is also classified as a check valve.
Explosion-proof valves, accident valves, etc., the effect of safety valves is to avoid the medium pressure in the pipeline or equipment from exceeding the specified value, so as to achieve the purpose of safety protection.
Regulating valves, saving valves and pressure reducing valves, the effect of which is to regulate the pressure, flow and other parameters of the medium.
(2) Vacuum: such as vacuum ball valves, vacuum baffle valves, vacuum inflation valves, pneumatic vacuum valves, etc. Its effect is that in the vacuum system, the vacuum system element used to change the direction of the air flow, adjust the air flow rate, cut off or connect the pipeline is called a vacuum valve.
(3) Special uses: such as pigging valves, venting valves, sewage valves, exhaust valves, filters, etc. Exhaust valve is an indispensable auxiliary component in the pipeline system, which is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. It is often installed at the commanding height or elbow to sweep away the remaining gas in the pipeline, improve the power of the pipeline and reduce energy consumption.
By the main parameters
By nominal pressure
(1) Vacuum valve: refers to the valve whose working pressure is lower than the standard atmospheric pressure.
(2) Low pressure valve: refers to the valve with nominal pressure PN ≤1.6Mpa.
(3) Medium pressure valve: refers to the valve with nominal pressure PN of 2.5Mpa, 4.0Mpa and 6.4Mpa.
(4) High pressure valve: refers to the valve with nominal pressure PN of 10.0Mpa - 80.0Mpa.
(5) Ultra-high pressure valve: refers to the valve with nominal pressure PN≥100.0Mpa.
(6) Filter: refers to the nominal pressure PN of 1.0Mpa and 1.6Mpa
By operating temperature
(1) Ultra-low temperature valve: used for the medium working temperature t<-101°C valve.
(2) Normal temperature valve: used for medium working temperature - 29 °C (3) Medium temperature valve: used for medium working temperature 120 °C (4) High temperature valve: used for medium working temperature t>425 °C valve.
|
More on that
|
Pneumatic control valve inspection parts and daily maintenance - Wuzhong instrument
Pneumatic control valve is one of the instruments widely used in petrochemical enterprises. It is of great significance to ensure the normal operation and safe production of the process equipment by operating accurately and normally. Therefore, it is necessary to strengthen the maintenance of pneumatic control valves.
First, the key points to check the location during maintenance
...
|
|
The relationship between the valve diameter and the flow rate of the medium
The flow rate and velocity of the valve mainly depend on the diameter of the valve, and are also related to the resistance of the structure of the valve to the medium, and at the same time have an intrinsic relationship with the pressure, temperature and concentration of the medium of the valve.
Two...
|
|
Wuzhong instrument - what is the anti-loosening effect of spring washers?
In all kinds of mechanical connectors, the anti-loosening of bolts is a very important link. So can the tension spring washer be loosened?
The principle of anti-loosening of the tension spring washer
The anti-loosening principle of the tension spring washer is that after flattening the tension spring washer, the tension spring ...
|
|
Product features of eccentric hemispherical valve - Wuzhong instrument
(1) The sealing pair is spherical, disc eccentricity rotation planning
The valve sealing pair is spherical planning, and the sealing effect is good. Together with the disc rotation center is planned to have a bias with the center of the valve seat, so the valve disc and the valve seat form a bias cam wedge sealing effect when closed, the valve ...
|
|
Valve corrosion and how to fix it
1. The corrosion of the valve is usually understood as the damage to the metal material of the valve under the chemical or electrochemical environmental effect. Because the corrosion phenomenon is presented in the spontaneous interaction between the metal and the surrounding environment, therefore, how to isolate the metal from the surrounding environment or more use non-...
|
|
Advantages of pneumatic O-type shut-off ball valve - Wuzhong instrument
It is composed of a pneumatic O-type shut-off ball valve and a pneumatic double-acting actuator. It has the advantages of simple structure, small size, light weight, convenient operation, etc., and can be widely used in automatic conditioning and long-distance control of industrial production processes such as petroleum, chemical industry, hydropower, and textile.
...
|
|
Wuzhong instrument - common industrial pipeline identification specifications and colors
First, the effect of pipeline identification
Why do you need to do pipeline identification?
Intent: To facilitate the identification of substances in industrial pipelines, ensure safe production, and avoid misjudgment in operation and equipment maintenance. Carry out ...
|
|
The difference between pneumatic shut-off valve and pneumatic control valve - Wuzhong instrument
1. Pneumatic valves include conditioning valves and blocking valves, the effect of the two is different, although the flow rate of the conditioning valve can also be adjusted to 0, but the blocking valve is generally used for urgent blocking, and the valve positioner is generally a cylinder valve. The conditioning valve is with a pneumatic membrane and a large disc, in addition to being able to ...
|
|
How to use thermocouples in Wuzhong meters
The correct use of thermocouples can not only accurately obtain the temperature value and ensure that the product is qualified, but also save the data consumption of thermocouples, which can not only save money but also ensure product quality. Incorrect installations, errors such as thermal conductivity and time lag are the first errors in the use of thermocouples.
|
|
Precautions for valve installation - Wuzhong instrument
1. Before the device, check whether the valve has notched parts, whether the type is correct, whether there are debris in the valve body, and whether the muffler is blocked.
2. Close the valve and cylinder.
3. Device the cylinder on the valve, the direction of the equipment is parallel or straightened with the valve body, and check whether the screw holes are aligned.
|
|
Wuzhong instrument pneumatic valve fault location analysis
1. In the case of interlocking action of pneumatic valve equipment, the valve orientation should have the following situations:
The EC air supply is discarded and the valve is in a closed position
FO__ air source is discarded, and the valve is in the opening position
FL-_ The air source is lost, and the valve is in the time position and has been insisting
FL ...
|
|
Pre-assembly requirements for valves
1. According to the processing requirements, some parts need to be polished, and there can be no processing burrs on the appearance;
2. All parts are degreased;
3. After the degreasing is completed, pickling and passivation will be carried out, and the cleaning agent does not contain phosphorus;
4. Rinse with pure water after pickling and passivation.
|
|
Wuzhong instrument valve ten knowledge terms
1) General purpose valve (general purpose valve): a general term for a wide range of valves, also known as ordinary valves. It is not a valve for a specific condition and a specific purpose.
Although there is no clear definition of a universal valve, it mainly refers to a pressure below 2MPa, ...
|
|
Advantages and disadvantages of Wuzhong instrument gate valve
Gate valves have the following advantages:
Low fluid resistance: the medium channel inside the valve body is straight, and the medium does not change its direction of activity when it flows through the gate valve.
The torque required for opening and closing is small;
It can be used on a ring network pipeline where the medium moves in both directions, that is, the flow direction of the medium is not ...
|
|
Wuzhong instrument gate valve movement mode
When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, only rely on the medium pressure to press the sealing surface of the ram to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, it is necessary to rely on external force to forcibly ...
|
|
Valve pressure test method - Wuzhong instrument
The commonly used medium for valve pressure test is water, oil, air, steam, nitrogen, etc., and the pressure test methods of various valves are as follows.
(1) Globe valve and throttle valve The strength test of globe valve and throttle valve, usually the assembled valve is placed in the pressure test frame, the valve disc is turned over, and the medium is injected to...
|
|
Check valve selection points - Wuzhong instrument
Check valve, also known as check valve, check valve, is a valve used to avoid the backflow of medium in the pipeline, belongs to a class of active valves, because the pump in the abort operation, the medium will flow backwards, if there is no device check valve at this moment, the water hammer effect will occur in the process of backflow, the pipeline ...
|
|
The use of butterfly valves - Wuzhong instrument
Selection:
The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. The butterfly valve has a simple structure, small size, light weight, only a few parts, and only needs to rotate 90° to quickly open and close, the operation is simple, and the ...
|
|
Three-phase asynchronous motor to achieve variable speed method
1. Pole change speed regulation
This speed regulation method is to change the number of stator pole pairs of the cage motor to achieve the speed regulation intention by changing the wiring method of the stator winding, and the characteristics are as follows: it has hard mechanical characteristics and good stability; No slip loss, high power; The wiring is simple, the operation is convenient, and the price is ...
|
|
The selection of Wuzhong instrument control valve
In the process control system, the control valve accepts the control signal of the control instrument, directly touches with the fluid, adjusts the flow of the fluid, and controls the flow, pressure, temperature, liquid level and other elements in the system, so it understands the fundamental structure and characteristics of the control valve, and selects it correctly according to the process conditions of the system. ...
|
|
Contact
working hours
