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Valve Terminology

Oct 28, 2016

Following flow media, headstock headstock force and torque, speed, sensitivity and reliability, service life described

Valve is the valve sealing performance of seal's ability to prevent media leaks, it is the most important valve technical performance indicators. Valve seals in three parts: sluice gate and valve seat sealing surface at the contact between the two; packed with the valve stem and the stuffing of the distribution and branch; valve body and valve are covered and the joints. One previous leak called the internal leakage, which is commonly referred to as doesn't stay closed, it will affect the ability of valve truncated media. Cut off valves, leakage is not allowed. Two of the leaks is called leakage, that media leaks from within the valve out of the valve. Leakage would cause material loss, environmental pollution, which can also cause accidents. For inflammable, explosive, toxic or radioactive medium, leakage is not allowed, thus the valves must have a reliable sealing performance.

First, mobile media

Medium flowing through the valve after the pressure losses (both before and after the valve pressure difference), valve of the flow medium have a certain resistance, the media will consume a certain amount of energy to overcome the resistance of the valve. From energy conservation considerations, designing and manufacturing valves, to minimize valve on the flow resistance of the medium.

Second, the headstock headstock force and torque

Headstock headstock force and torque is the valve opening or closing force or torque that must be applied. Close valve Shi, need makes opening and closing pieces and sent seat two sealed surface between formed must of sealed than pressure, while also to overcome valve rod and filler Zhijian, and valve rod and nut of thread Zhijian, and valve rod end Department supports at and the other mill wipe parts of friction, thus must imposed must of close force and close torque, valve in opening and closing process in the, by need of opening and closing force and opening and closing torque is changes of, its maximum value is in close of eventually instantaneous or opened of initially instantaneous. Designing and manufacturing valves should seek to reduce the closing force and closing moments.

Third, the opening and closing speed

Valves for opening and closing speed is completed once opens or closes the time needed to say. Generally no strict requirements of valve opening and closing speed, but some conditions on the opening and closing speed of special requirements, such as prompt to open or close in case of accident, some require slow closed to prevent water hammer and so on, should be taken into account when this valve type is selected.

Four, action sensitivity and reliabi

This parameter is the valve for medium, reaction sensitivity accordingly. Throttle valve, pressure relief valve, control valves used to regulate the media parameters, such as valves and safety valves, steam traps, valves with particular features, its function and reliability sensitivity is a very important technical performance indicators.

Five, the service life

It said the durability of the valve, valve is an important performance indicator, and is of great economic importance. Usually expressed as a number of opening and closing to ensure the sealed request, can also be expressed as a time.