Do you know the reason for the failure of the ultra-high pressure valve and the improvement method?

At present, ultra-high pressure technology has been widely used in the fields of superhard material manufacturing, chemical industry, petrochemical industry, processing technology, and geomechanics research. Due to the widespread use of high-pressure technology, the performance of the ultra-high-pressure valve in the ultra-high-pressure system directly affects the reliability, safety, work efficiency and service life of the entire system. Analyzing its failure mode and finding a reasonable solution will help improve the quality and life of the product.

 

 

Structure of ultra-high pressure valve

Ultra-high pressure needle valves generally adopt an angular single-seat structure, which is simple to process, and the valve core is a single-guide structure. The angle-shaped single-seat valve has a simple flow path and low resistance. It is suitable for fluids with high pressure difference, high viscosity, suspended solids and particulate matter. It can avoid coking and blockage, and is also convenient for self-cleaning.

 

The valve core and the valve seat are the two core parts of the ultra-high pressure needle valve for on-off control, forming the dynamic seal pair of the ultra-high pressure needle valve switch. By controlling the contact and separation of the tapered sealing surface between the valve core and the valve seat, the valve channel is closed and opened.

 

 

Common failure modes of ultra-high pressure valves

1. Bending and cracking of the valve core

 The bending deformation of the needle valve core and the fracture of the sealing surface are mainly caused by the coaxiality error or the conical error of the valve core and the valve seat during processing. In addition, because the needle valve switch used is manual, it receives too much force when sealing, and it squeezes against the valve seat to cause chipping.

 

 

2. Wear of sealing surface

The wear of the sealing surface is related to cavitation, erosion and high temperature corrosion. Needle valves usually work under high pressure difference. The flow velocity near the contact ring between the valve core and the valve seat is extremely high, and the vaporization pressure of water is high, so cavitation and flashing are easy to occur in the ultra-high pressure valve. The oxygen content in the water, the shape of the valve core, the valve opening, the outlet back pressure, etc. all have an effect on cavitation.

 

 

Improved method of ultra-high pressure valve

1. Heat treatment and surface hardening treatment

For the materials used in ultra-high pressure valves, heat treatment and surface hardening are usually used to improve their anti-extrusion and erosion resistance properties.

 

2. Vacuum heat treatment

Vacuum heat treatment refers to the heat treatment process in which the workpiece is placed in a vacuum. Vacuum heat treatment does not produce oxidation, decarburization and other corrosion during heating, and has the effect of purifying the surface and degreasing and degreasing. In the vacuum, the hydrogen, nitrogen, and oxygen absorbed by the material during the smelting process can be removed to improve the quality and performance of the material.

 

 

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