The actual operation of the safety valve

A: the safety valve to open the pressure adjustment ① safety valve factory, it should be adjusted one by one to its pressure to the user set the desired value. If the user puts forward the working pressure level of the spring, press the lower limit of the pressure level to adjust the factory normally. ② Before installing the safety valve on the equipment to be protected or before installation, the user must re-adjust the installation site to ensure that the setting value of the safety valve meets the requirements. (3) Within the range of the spring working pressure indicated on the nameplate, the opening pressure can be adjusted by rotating the adjusting screw to change the amount of spring compression. ④ Before rotating the adjusting screw, the inlet pressure of the valve should be reduced to less than 90% of the opening pressure to prevent the valve disc from being rotated when the adjusting screw is rotated, so as to damage the sealing surface. ⑤ In order to ensure that the opening pressure value is accurate, the media conditions, such as the type and temperature of the medium, should be adjusted as close to the actual operating conditions as possible. Changes in the type of media, especially when the media is not the same state of accumulation (for example, from liquid to gas phase), the cracking pressure often varies. Operating temperature increases, the opening pressure is generally reduced. Therefore, when adjusted at room temperature for high temperature, the setting pressure at room temperature should be slightly higher than the required opening pressure. To what extent and the valve structure and material selection are related, should be based on the manufacturer's instructions. ⑥ conventional safety valve for fixed additional back pressure occasions, when the test is adjusted to open pressure (back pressure at this time atmospheric pressure), the setting value should be required to open the pressure value minus the additional back pressure value. Two: relief valve relief pressure and back seat pressure adjustment ① adjust the valve discharge pressure and back seat pressure, the valve must be fully open to the height of the action test, therefore, only in high-capacity test equipment or safety valve installed to be After the protection of equipment on the possible. The adjustment method according to the valve structure is different. ② For the structure with recoil plate and seat adjusting ring, the seat adjusting ring is used for adjustment. Unscrew the adjusting ring fixing screw, extending from the exposed screw hole a thin iron rod and the like tools, you can dial the gear ring on the adjustment ring, the adjustment ring around. When the adjustment ring to the left counterclockwise rotation, its position increased, the discharge pressure and the seat back pressure will be reduced. Conversely, when the adjustment ring is rotated clockwise to the right, its position is lowered and both the discharge pressure and the seatback pressure are increased. Each adjustment, the adjustment: circle rotation range should not be too large (generally rotate the number of teeth can be). After each adjustment, the fixing screw should be screwed up so that the end is located in the groove between two teeth of the adjusting ring, so as to prevent the adjusting ring from rotating without generating radial pressure on the adjusting ring. For safety reasons, the dial should be adjusted before adjusting the pressure relief valve should be appropriate to reduce the pressure (generally should be less than 90% of the opening pressure) to prevent the valve suddenly opened in the adjustment, causing an accident. ③ For the upper and lower adjustment ring (guide sleeve and valve seat each have a regulation ring) structure, the adjustment to be more complex. The seat adjusting ring is used to change the size of the passage between the valve flap and the adjusting ring so as to change the pressure accumulation in the cavity between the valve flap and the adjusting ring when the valve is initially opened. When the valve seat adjusting ring is raised, the degree of pressure build-up increases, so that the phase of valve opening is reduced and the sudden snap-on is reached quickly. Therefore, raising the seat ring can reduce the discharge pressure. It should be noted that the seat ring can not be raised too close to the valve flap too close. In that case, the leakage at the sealing surface may cause the valve to suddenly open prematurely, but because of the medium pressure is not enough to keep the valve in the open position, the valve flap then closed again, so the valve frequency hopping. Seat adjustment: "The ring is mainly used to reduce the valve ratio, open the stage and adjust the discharge pressure, but also have an impact on the seatback pressure. The upper adjusting ring is used to change the angle at which the flowing medium is folded after being reflected on the lower side of the valve flap so as to change the magnitude of the fluid acting force so as to adjust the seat back pressure. When the upper adjusting ring is raised, the turning angle decreases and the fluid force decreases. As a result, the pressure of the seatback increases. Conversely, when lowering the upper adjustment ring, the seatback pressure is reduced. Of course, the upper adjusting ring changes the back seat pressure, but also affects the discharge pressure, that is, raising the upper adjusting ring to increase the discharge pressure and reducing the upper adjusting ring to reduce the discharge pressure, but the impact is not as good as Seat pressure so obvious. Search Keyword: More Valve Technical Articles

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