Petrochemical industry pump shaft seal is roughly divided into contact seal, non-contact seal two categories. Contact seals include packing seals and mechanical seals; non-contact seals with labyrinth seals, spiral seals and vice impeller seals. 80 ~ 90% of petrochemical industry chemical pump using mechanical seal. The use of mechanical seals is an effective way to solve the problems of running, running, dripping, leaking, improving environmental protection, improving working efficiency and reducing production cost. It is one of the indispensable means to realize industrial modernization. Study drip Guangzhou Haotian Chemical Company ZW600-80-type forced circulation pump, flow 2650m3 / h, pump slurry containing 8% to 10% (wt) or even higher salt crystals, the transfer fluid temperature up to 120 ℃. The shaft seal structure comprises a shaft sleeve, a front machine cover, a seal ring, a pump cover, a back machine cover, a water seal cover and two sets of the two sets installed between them in tandem and independent from each other Mechanical seal, mechanical seal 1 Balanced external static compensation ring machine seal, mechanical seal 2 with double-end fork fork machine seal. Kaiping Guangdong Polyester Enterprise Group slurry pump is Roots pump, slurry medium density l350m3 / kg, the outlet pressure 600kPa, motor speed 1500r / min. The seal of the slurry is in the form of a mechanical seal; the EG is used for flushing, and the seal is sealed with a skeleton oil seal to prevent the flushing fluid from leaking. The improvement measures include: changing the seal position of the O ring at both ends of the push ring and adopting the fluorine rubber O ring; using the PTEF material to make a oil seal similar to the frame oil seal, which is installed between the fixing ring fixing seat and the pump body to prevent the pulp Into the moving material, static ring sealing surface. Japan's Mitsubishi Heavy Industries 93A reactor cooling pump (RCP) shaft seal system includes three seals. The first seal (primary seal) is a film-riding end seal that controls leaks and uses a non-contact controlled leak system to provide less deviation over long periods of operation (about 1 year). The role of the No. 1 seal is to reduce the pressure of the coolant from 15 MPa to 0.3 MPa, including the rotary side seal runner and the stationary side seal ring. Joseph L Foszcz from the United States wrote an overview of shaft seals, claiming that the mechanical seal can handle a wide range of fluids at pressures up to 13.8 MPa, speeds up to 50000 rpm and temperatures from -254 to 649 ° C. Pump applications that do not allow leaks are gaining in popularity. The article gives a typical mechanical seal assembly, including a seal, a seal ring, stationary seal ring, O-ring (2 seal) and so on. Some patent introduction Guangzhou Pump Factory's Chinese utility model patent ZL discloses a combination of sealed leak-free pump includes a rotating spindle, impeller, pump cover, machine cover and other components, the rotating spindle, impeller, pump cover and machine cover Set the parallel set of two sets of mechanical seals, the outer seal is close to the pump cover single-end balanced static compensator (first stage seal), the inner seal is close to the rotating spindle double-sided machine seal The second stage of sealing), the pump installed in the pump by the combination of mechanical seal, the transmission medium and the separation medium separated from the liquid medium to prevent leakage through the rotating shaft to the outer space. U.S. Patent No. 5,501,470, filed by Japan's NIPPON PILLAR PACKING CO., LTD., Discloses a non-contact shaft seal for rotary machines that creates a fluid film seal on the high pressure side of the shaft seal face. A plurality of pressure grooves are arranged in radial or peripheral direction on the rotating sealing surface to generate dynamic pressure in the fluid film. JP 198219297 filed by Mitsubishi Heavy Industries of Japan discloses a shaft seal suitable for a high-pressure rotary machine in which a high-pressure chamber and a low-pressure chamber are hermetically sealed with a plurality of grooves on the rotating ring so as to rotate the fluid along the rotation shaft Peripheral delivery. Japanese Patent JP filed by Japan NIPPON PILLAR PACKING CO LTD discloses that the shaft sealing device is a two-way machine seal for high-pressure equipment. The first machine seal is inserted into the rotary seal ring by the two-stage sealing member so that the second sleeve can move relatively in the axial direction so that the first stationary side retainer can keep the first stationary seal ring inserted in the first sleeve. This structure can reduce the size and weight. Standard conditions The following three standards deserve attention. 1. The American Petroleum Institute Standard API 682 "Pumps-Shaft Sealing System for Centrifugal and Rotary Pumps 3rd Ed. 2004" (ISO 21049: 2004) requires that the shaft seal system be operated continuously for 25000h without replacement; Three seal arrangements are given, Arrangement 3 Each bushing assembly contains 2 seals, using an externally supplied stop-leak fluid and an internal seal should have an internal (reverse) balance feature to withstand without opening Reverse pressure changes. 2, API 614 "Lubrication, Shaft-Sealing, and Contro-Oil System and Auxilaries for Petroleum, Chemical, and Gas Industry Services 4th Ed., 1999" for Oil, Chemical and Natural Gas Industries 3, BS EN ISO 10438: 2003 "Petroleum, petrochemical and natural gas industries-lubrication, shaft-sealing and control-oil systems and auxiliaries" - Petroleum, petrochemical and natural gas industries - Lubrication, shaft sealing and oil control systems and accessories. References: 1, chemical forced circulation pump shaft seal structure transformation - water pump technology .2001 (2) .- 41-43 2, slurry pump shaft seal failure analysis and improvement measures - chemical fiber and textile technology .2004 (4) .- 39-40 3, A guide to shaft seals - Plant Engineering, Mar 2001. Vol.55.Iss.3; p77-85 4. Improved Shaft Seal for 93A Type Reactor Coolant Pump - Mitsubishi Heavy Industries , Lte. Technical Review Vol.42 No.1 (Feb. 2005) 5, Combined Sealed Leakage Pump - X (Application Date: grooved face pattern - US5501470 (filing date) 7. Mechanical seal for shaft seal part for high pressure rotary machine - has rotating ring with number of grooves of to transport fluid to peripheral direction with rotation of rotary shaft - JP8219297 Japanese Open Date) 8, shaft seal device - JP (the date of filing)
