【 Weak current College 】 control valve common troubleshooting methods (1)

First, increase the life of (8)
1) large opening work longer method
Let control valve at the beginning as the maximum opening, as 90%. In this way, erosion, cavitation, broke in the valve head. As the valve damage, traffic increases, the valve and then closes it, undermine this constantly, and gradually turned off, the entire spool fully used until the valve sealing surface damage the roots and cannot be used. At the same time, the big opening work cutting gap, erosion, which is more than a start valve to open degree in middle and small open CV working to improve life on a 1 to 5 times more. Where a chemical plant using this method, the valve service life increased 2 times.
2) decreasing the S increase work open to improving life method
Reduce S, namely the increased system foreign except control valve so that the allocation of losses to reduce pressure on the valve, guarantee the flow through the valve will increase the control valve to open degree, at the same time, pressure reducing valve, the gas corrosion, erosion or weakened. Specific measures are: the valve after set pressure orifice plate cutting consumption; shut down the pipeline series manual valve, to the control valve for a ideal job opening. On the start valve selected big in a small opening work, the use of this method is very simple, easy, and effective.
Reduced diameter increase 3) job opening to improve life method
Through the valve diameter decreases to increase job opening, specific measures are: ① swap with a smaller file size of the valve, such as swap DN25 DN32; ② body does not change, replace the small diameter of the valve seat valve seat. Where a chemical factory overhaul is throttling element dgl0 replaced, life expectancy increased dg8 1 times.
4) transfer failure location improve life method
The destruction of serious place over to a secondary position in order to protect the valve seat sealing surface and cut surface.
5) growth throttle channel improvelife method
Growth throttle channel the simplest is the thickening of the seat, the seat hole growth, forming a longer throttle channel. On the one hand makes the stream closed-throttle back suddenly expanded delay, position, since the transfer of destruction from the role of sealing the surface; on the other hand, also increased the throttle resistance, reducing the degree of pressure recovery, so that the steam Eclipse. There is the seat of the hole designed to sidestep, waves, is in order to increase the resistance, undermine the steam Eclipse. This approach to the introduction of high pressure valve and the old valve be improved when in use, is also very effective.
6) change flow direction prolonging method
Flow direction towards open-open a stream, the primary role of cavitation erosion, in a sealed surface, so that the valve core roots and spool valve seat sealing surface will quickly erode; stream closed-directional flow towards the closed, cavitation erosion role in cutting, the seating surface following, protecting sealing surface and valve core roots and extends the service life. Pretended to flow out of the use of the valve, when the extended life of the more prominent, you can extend the life change flow direction 1 ~ 2 times.
7) use of special materials improve life method
For cavitation (devastation shapes such as honeycomb dot) and scour (streamline small Groove) that can be switched to Eclipse and erosion of special materials for the manufacture of throttling element. This special materials have 6YC-1, A4 steel, Division too, carbide, etc. For corrosion resistance, instead, more corrosion-resistant and have a certain mechanical, physical properties of materials. This material is divided into non-metallic materials (such as rubber and PTFE, ceramic, and so on) and metallic materials (such as monel, Hastelloy, etc.).
8) change valve structure, increasing life expectancy method
To change the valve structure or use a longer servicelife of the valve to achieve the goal of improving life, such as selection of multi-stage type valves, counter-steam Eclipse valve, corrosion resistant valves, etc.