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How to select a valve with a longer life

Update:12-01-2019
Summary:

The flow-opening type flows toward the opening directio […]

The flow-opening type flows toward the opening direction, and the cavitation and erosion mainly act on the sealing surface, so that the sealing surface of the valve core and the valve seat is quickly damaged; the flow-closing type flows toward the closed direction, cavitation and erosion. After throttling, below the seat sealing surface, the sealing surface and the root of the valve plug are protected, extending life. Therefore, when the valve for the flow-open type is used, when the problem of prolonging the life is more prominent, the life can be extended by one to two times by simply changing the flow direction.

In order to resist cavitation (destruction of shapes such as honeycomb dots) and scouring (streamlined small grooves), special materials resistant to cavitation and erosion can be used to manufacture the throttle. This special material is 6YC-1, A4 steel, stellite, hard alloy and so on. For corrosion resistance, materials that are more resistant to corrosion and have certain mechanical and physical properties can be used. This material is divided into non-metallic materials (such as rubber, PTFE, ceramics, etc.) and metal materials (such as Monel, Hastelloy, etc.).

The purpose of improving the life is to change the valve structure or to select a valve with a longer life, such as a multi-stage valve, an anti-cavitation valve, a corrosion-resistant valve, and the like. The welding slag, rust, slag, etc. in the pipeline are blocked or jammed in the orifice, the guiding part and the balance hole of the lower bonnet, causing strain and scratches on the curved surface of the valve core, the guiding surface, and indentation on the sealing surface. Wait. This often happens in the early stages of the new commissioning system and after the overhaul. This is the most common failure. In this case, it must be unloaded for cleaning, remove the slag, if the sealing surface is damaged, it should be ground; at the same time, the bottom plug is opened to wash off the slag falling into the lower bonnet from the balance hole, and the pipeline Rinse. Before commissioning, let the regulating valve open completely, and the medium will flow into the normal operation after a period of time.

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