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Electric regulating valve in high demand for industrial automation applications

In high-demand industrial automation applications, electric control valves tend to legislate, thus cutting off the function is to cut off the important use of functional and internal quality indicators. In the field use, the regulator will often appear bad, large leakage cut. In addition to interception, let the pressure difference is too small, and open the top, such as increased leakage, mainly due to structural defects and improper selection of the valve. The following form and function, the truncation selection made a comprehensive introduction.

First, the choice of structural type
Double seal type regulators (such as double seat valves, double sealed sleeve valves, etc.) are a significant adverse leak. But in 1980, this is a popular front sleeve valve, however, many manufacturers sleeve valves up and down, but much work to improve and structure to reduce leakage, making it a very complex structure. So, it brings a lot of shortages, some of the poor reliability, maintenance and spare parts, the judge is not difficult, the effect is not ideal, and so on. In fact, this is a design concept for the wrong body, "heart" such a complex change can also be achieved through external adjustment. Therefore, we should choose a single-stage control seal. Therefore, sealing, reliability issues, repair problems and spare parts and solve problems. At this time, the focus of the conflict to resolve the media imbalance increased, this only deal with strong, bold push the piston dry. Through an external solution, through the complex interior than the obvious increase, easier, it is not so much way than expected. In the nineties, people began to seek more reliable, simple structure, sealed globe valve. At this time, the rotary valve, straight stroke valve (single seat valve, gate valve, sleeve valve) has more advantages, the production of three eccentric butterfly valves and shut-off valves close all functions, hard seal cut off the ball valve.

Second, select the sealing surface
(1) face to face seal:
60 ℃ ordinary piston-type spool, small 60 ℃ sealed bearing cone cone, cone width of 0.5 mm small small, usually often ~ 2 mm, the seal must ensure a good contact with the tube. But in fact, it is affecting the machining error accuracy (if not roundness, concentricity gradient), sealed, and the effect is not ideal. This type of valve leakage rate, usually recorded grinding accuracy of up to 10-6, can achieve a good seal.
(2) sealed ball:
Use a spherical spool to rotate and fix a small conical shape, they cut off, which is sealed between the lines of the secret good effect than face to face. Shenyang company launched ultra-light valve, functional ball seal butterfly valve is the case, the leakage rate of up to 10-6 ~ 10, high-performance three eccentric butterfly valve can be up to 10, zero leakage.

Third, the choice of sealing material
(1) soft seal
In addition to corrosion resistant valves, Li Ning is usually a soft seal spool or non-metallic material (mainly used for polytetrafluoroethylene (PTFE), rubber seal valve form). Soft seal valve sealing effect, but it is best to install in the pipeline, the system cleaning all can leave more or less unclean all kinds (slag, etc., feigangtie, etc.), adjust the flow, easy to soft seal the valve, spool Is cut off and improves the seal leakage and reliability of the poor. Therefore, the choice of soft seal structure must be considered before cleaning and flushing the pipeline.
(2) hard seal
Hard seal welding alloy cutting the best choice. Seal will also consider the service life and reliability, although the factory only 10 ~ index 10, short soft seal zero leakage, but close enough to the requirements of the partition, durable, from an economic point of view, more economical.

Fourth, the seal reliability considerations
(1) soft seal, cut off the effect is good, but no particles of the media, once the leakage is reduced, can be greatly improved.
Therefore, in the conditions agreed to try to use hard seal. Super light valve sealing function of up to 10-seven10, three eccentric butterfly valve can achieve zero leakage.
(2) Seal wear resistance considerations: In addition to the choice of type of hard seal leakage requirements, close to 10 (or institutions) alloy surfacing wear resistance increases, corrosion resistance, anti-scratch ability to seal, improve valve life.

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