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How should I choose valves?
The function of the valve and the factors that should be taken into account when selecting
What are the functions of valves and the factors that should be taken into account when selecting them?
The selection of valves is the result of a comprehensive and balanced comparison based on operational and safety and economic rationality. wesdom valves warmly reminds you that the following conditions must be considered before selecting a valve.
(1)Material state a. Material state of gas materials include: relevant physical data, pure gas or mixture, whether there are liquid droplets or solid particles, whether there are easily condensable components. b. Material state of liquid materials include.
(2)Relevant physical data, pure components or mixtures of whether to contain volatile components or dissolved gas (pressure reduction can be precipitated to form a two-phase flow), whether to contain solids in suspension, as well as the liquid viscosity, freezing point or pour point, etc.
(3) other properties, including corrosion, toxicity, solubility of valve construction materials, whether flammable and explosive properties. These properties sometimes not only affect the material, but also cause special requirements on the structure, or the need to improve the pipeline grade.
a. The pump outlet valve should take into account the maximum closing pressure of the pump, etc.
b. When the system regeneration temperature is much higher than the normal temperature and the pressure is reduced, for this type of system, the combined effect of temperature and pressure should be considered.
c. The degree of continuity of operation: i.e. the frequency of opening and closing of the valve, also affects the requirements for the degree of wear resistance. For systems with more frequent switching, consideration should be given to the installation of double valves.
a. The system allows a small pressure drop, or allow the pressure drop is not small but does not require flow adjustment, the valve type should be selected with a small pressure drop, such as gate valves, straight through the ball valve.
b. Need to regulate the flow, then you should choose a better adjustment performance, with a certain pressure drop valve type (pressure drop accounted for the proportion of the entire pipeline pressure drop and the sensitivity of the adjustment).
(3) the environment in which the valve: outdoor in cold areas, especially for chemical materials, the valve body material generally can not use cast iron and should be selected cast steel (or stainless steel).
(1) cut off: almost all the valves have a cut-off function. Used purely for cutting off and do not need to adjust the flow can be used gate valves, ball valves, etc., require rapid cut off, it is more appropriate to plug, ball valves, butterfly valves, etc.. The stop valve can both regulate the flow and can cut off. Butterfly valve can also be suitable for the regulation of large flow.
(2) change the direction of flow: the choice of two-way (channel for L-shaped) or three-way (channel for T-shaped) ball valve or plug, you can quickly change the direction of material flow, and because a valve to play the role of more than two straight through the valve, can simplify the operation, so that the switch is accurate, and can reduce the space occupied.
(3) regulation: stop valve, plunger valve can meet the general flow adjustment, needle valve can be used for micro fine adjustment; in the larger flow range for stable (pressure, flow) regulation, it is appropriate to throttle valve.
(4) Check: check valves can be used to prevent backflow of materials.
(5) different production processes can choose to have additional functions of the valve, such as with a jacket, with a clean mouth and with a bypass valve, there are used to prevent solid particles from settling with the blowing mouth valve.
4,The power to open and close the valve
The vast majority of valves operated in situ with handwheels, for operation with a certain distance, can be used sprockets or extension rods. Some large-diameter valves have been designed with motors in the valve because of the large starting torque.
In the explosion-proof zone to use the corresponding level of explosion-proof motor. Remote control valves take the power type of pneumatic, hydraulic, electric, etc., which electric can be divided into solenoid valve and motor-driven valve. It should be selected according to the need and the energy that can be provided.
