The high-pressure regulating valve maintenance and the entire valve repair projects, occupy a small proportion, but more expensive due to the price of the high-pressure regulating valve, the impression is to reduce the cost of the high-pressure regulating valve, it is meaningful Jiangyin Oulei Si valve repair Factory: pressure regulating valve repair, can indeed significantly reduce the cost of using high-pressure regulating valve, but reduce the failure of the pressure regulating valve, thereby reducing the number of high-pressure regulating valve repair is more important.
How to reduce the pressure regulating valve maintenance times? Jiangyin Oulei Si: mainly high-pressure control valve selection, use environment suitable pressure regulating valve, which can effectively improve the service life of the high-pressure regulating valve. The main problem is the use of high-pressure valve life. The general structure of the valve under the conditions of high pressure differential can only use 1 to 2 months, domestic and foreign manufacturers have made great efforts in order to solve the problem of the high-pressure valve short life, and explore a lot of material and structure , all kinds of products, mainly how-stage high-pressure valve, the labyrinth high pressure valve and single seat sleeve load type high-pressure valves, etc.. For one purpose, by reducing cavitation erosion, the destruction of the the flash physical phenomena valve, high pressure valve to increase service life, then we want to understand the following high-pressure regulating valve life cut short:
Shorten the life of the high-pressure regulating valve asked explanation questions:
Valve short life reasons led to the short life of the high-pressure valve for two main reasons: the cavitation erosion. Flashing, cavitation valve differential pressure (P1-P2) is greater than the largest media saturation pressure difference (△ Pmax), it will produce a flash, which then produce cavitation and valve internal and relative adjacent duct structure damage. Medium velocity through the orifice of the smallest cross-section is the largest. The increase in velocity (or kinetic energy) along with the pressure (or potential) is greatly reduced. When the pressure is lower than the saturated vapor pressure media, the bubbles will be formed in the medium. With the orifice at the pressure decline further, the bubbles will form a large number. There is no essential difference between this stage flashing and cavitation, but the possibility of damage to the structure of the valve, but it is certainly there.
Shorten the life of the high-pressure regulating valve to explain the two:
Flashing of the high-pressure regulating valve erosion: If the media through the orifice, the pressure is still lower than the the media saturation vapor pressure. The bubbles will be retained in the stream after the orifice, which we call the flash. Flashed cause severe erosion damage to the valve spool, which is characterized by scouring the surface of the smooth polished appearance. The most serious erosion damage is generally the highest flow rate the place, usually located in the valve plug and seat contact online or nearby. Especially in the small opening, throttle gap is small, the flow rate is high, erosion damage is the most serious. Therefore, the high-pressure valve should avoid small opening. Even the best valve, if long-term in a small opening, its life will be exponentially decreases. To avoid the small opening, the key calculation, selection, design institutes and users should pay more attention.
Shorten the life of the high-pressure regulating valve to explain the three:
High-pressure regulating valve flash the typical appearance cavitation destruction: On the other hand, If the media pressure in the medium flowing through the orifice restored to more than a media-saturated steam pressure, the bubble will burst or explosion inward, resulting in cavitation. Vapor bubbles burst releasing energy, and generates a noise similar to the gravel flow through the valve. If a solid surface of the bubbles in the proximity within the valve is broken, the energy released will slowly tearing the material, leaving the apertures of the honeycomb. The damaging effects of cavitation may extend to the adjacent downstream pipeline. Obviously, from the pressure recovery coefficient, high recovery valve more prone to cavitation, because the pressure in its orifice more likely to rise above the vapor pressure of saturated medium. The relationship between the the typical shape flashing and cavitation, erosion cavitation damage: small opening, orifice flow faster, less pressure, more medium bubble content, therefore, this time flashing destruction more severe erosion damage is a major contradiction. Large opening, the main contradiction is caused when the system pressure is restored to the saturation pressure above the cavitation damage. Therefore, the user should use the high-pressure differential valve to avoid the small opening, the manufacture of high-pressure valve manufacturers must have good anti-cavitation measures, otherwise, the valve will soon due to the role of cavitation, erosion damage.
Reduce pressure regulating valve repair method: a mature anti-cavitation high pressure valve is now up to the high-pressure valve structure is divided mainly for multi-stage high-pressure valve, the labyrinth high pressure valve and a single seat the sleeve load of high-pressure valve categories . Usage, they have their own advantages, but the multi-level and high-pressure labyrinth complex internal structure, spare parts preparation and replacement more difficult, inconvenient to use. For these situations, Hualin has developed a single-seat the load style fine small high-pressure anti-cavitation valve. The product is simple and spare parts replacement, easy maintenance, and a good solution to the above problem. In 1992, the product obtained national patents (the anti-cavitation high pressure valve orifice + single seat valve + sleeve valve three throttle structure:
● once throttle - to take over the reduced diameter (① Department) is equivalent to the orifice throttling, 10% of the total pressure drop.
● secondary throttle - single-seat throttle (main throttle, ② Department) single seat valve structure, accounting for about 30% of the total pressure drop. This article comes from weaving dreams
● three throttle - sleeve throttle sleeve structure (③ Department), the total pressure drop of 60%.
Pneumatic film anti-steam eclipse high pressure valve orifice + single seat valve + sleeve valve "three throttle structural, pressure drop through the valve into a number of smaller pressure drop to ensure that its section in each of the smaller pressure drop greater than the saturated vapor pressure of the flow at the surface minimum pressure to avoid or mitigate the damaging effects of the flash effect on the valve. The throttling element structure of the sleeve hole injection to replace the conventional guide bushing + seat "approach can eradicate the guide bushing easy loose, hole injection throttle structure can reduce the choke on spool seat unilateral partial destruction of the role of to reduce throttle dumb tone. Because the orifice injection mode withstand valve throttling pressure drop, the majority (about 60%), the destructive effects of cavitation relocated by the valve seat hole, the protection of the sealing surface, to improve the valve life, up to ordinary high The differential valve 2 to 3 times. The correct selection of high quality and appropriate use of the conditions of high pressure regulating valve model, an effective reduction of the high-pressure regulating valve repair.
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