The valve flow characteristics and tightness of the unit's dredging system directly affect the unit's vacuum. The valves of the dredging water system connected to the condenser are all imported from abroad. The leakage level of the valves is generally above five, so as to ensure the tightness of the dredging water system during normal operation. In particular, the small engine exhaust disc valve was selected as Adams's three-compartment disc valve to prevent the small machine from stopping due to lax exhaust and affecting the vacuum. The vacuum pump unit is the main equipment of the vacuum system. When the unit is running, the standby vacuum pump unit is always in the linkage standby state, and the auxiliary equipment cooler is always running. Especially in summer, the temperature of cooling water is high. If the heat transfer effect of the cooler is not good, the vacuum pump output will be reduced, which will affect the operation of the unit. Therefore, chiller cleaning is the main task of routine maintenance of the vacuum pump set. Therefore, the choice of vacuum pump unit cooler cold water valve should be considered in the original design based on a higher level of the valve, while requiring the cooler must have a back flushing sewage system. The performance of the automatic replenishment valve in the replenishing system of the vacuum pump must be reliable. At the same time, the isolation door should be designed to ensure the automatic replenishment valve processing during the operation of the chiller. The main equipment before leaving the factory strictly control the connection between the condenser and the low-pressure cylinder U expansion joint condenser and low-pressure cylinder connection U expansion joint is the weakest part of the vacuum system, it is welded by the =1.5mm stainless steel plate of. Because the stainless steel plate is thinner, the welding process is required to be stricter. Other power plants of the same type have experienced improper welding procedures and installation methods, which caused the shutdown of U-expanded welded joints. During inspection of U-expanding joint welding process and acceptance of hydraulic pressure test, the power plant shall organize the relevant construction personnel to jointly discuss the installation process with the manufacturer to enable the construction unit to master the installation process and precautions so as to ensure the installation quality. The tightness of the low-pressure cylinder block pumping and the combination of the cylinder block low-pressure cylinder is the main component of the unit vacuum system. The tightness of the cylinders directly affects the vacuum of the unit. In particular, the lower part of the low pressure cylinder shaft seal, conventional irrigation test can not be leaked. Because the crews participate in the peak load adjustment operations of different degrees, the cylinders of the low pressure cylinders are often deformed. The most obvious part of the reaction is the joint surface of the low pressure cylinders. Therefore, the company's experienced supervisors and technicians will join the factory representatives to participate in the low-pressure cylinder block pumping test and the tightness inspection of the cylinder joint surface at the Shanghai Steam Turbine Works. It is found that the problem requires the manufacturer to deal with it in time. Digest the problem before the device leaves the factory. It is a long-term problem to solve the vacuum problem of the unit that the rubber ball cleaning system equipment ball cleaning system can be put into operation normally. Because most of the power plants have problems with rubber ball cleaning system design, equipment quality, and installation, the rubber ball cleaning system cannot be put into operation. Our company sent strong professional and technical personnel to Qingdao Power Equipment Factory for acceptance. The main focus is on equipment performance and quality. Because the net is a circulating water system equipment, the circulating water quality is poor and it is easy to foul. If the flexibility of the receiving net is not good, it will affect the switch of the net and cause the electric putter motor to be burned. It is required that the water net shaft packing chamber should be filled with high water-based packing. The tightness of the receiving net is not good, and it directly affects the ball collection rate of the rubber ball cleaning system. It requires that the perimeter of the surrounding belt and the wall of the cylinder fit tightly, and the gap between individual tight edges should not exceed 3 mm; the import end of the net plate should be tightly fitted to each other. The gap is not stricter than 2mm; the perimeter of the ball collection chamber is tightly fitted with the cylinder wall, and the gap is not more than 3mm. The equipment installation stage must control the construction process to conscientiously implement the thermal power construction quality acceptance and assessment standards and the construction and acceptance technical specifications. Steam turbine section 31 Condenser copper pipe installation According to the Technical Supervision Office of Anhui Electric Power Industry Bureau [1999] No. 5 on strengthening the condenser Notices on the supervision and inspection of copper tubes, guidelines for the selection of condenser tubes in thermal power plants, acceptance and evaluation standards for thermal power construction quality, and requirements for construction and acceptance specifications (in view of the steam turbine), 100% eddy current testing for condenser copper tubes , Residual stress (1/1000) ammonia fuming test, process performance flattening and expansion (1/1000) test. Before the installation of the copper coils of the two condensers of our company, 38,848 eddy current inspections were performed, of which 779 were unqualified and replaced. If the condenser copper pipe is blocked due to leakage after installation, the condenser heat exchange area is reduced, and the condensed water quality is also affected. Circulating water system equipment installation Rubber ball rinsing system Because the pipeline diameter is small, there is no design drawing for installation. The construction unit needs to be installed according to the actual situation on site. The system requires short piping, smooth elbows, and tight piping. Pipeline system resistance (including ball room and valve) shall meet the requirements of (A1): p1g(H-2)-5i=2p1A1p1 Rubber ball pipe system water resistance, pa; rubber ball pipe system water density kg /m3;g free fall weight acceleration, m/s2; H plastic ball pump design head, mp2 pitching tube (a piece of rubber ball pipe extending into the condenser water circulating water inlet pipe) is exported to the condenser circulating water inlet Recirculating water pipe system water resistance, pa; p3 condenser design water resistance, pa; p4 condenser water circulating water outlet to the net receiving inlet circulating water pipe system water resistance, pa; p5 collecting net water resistance, pa; rubber ball The flushing system is required to minimize the resistance of the pipe elbow. To solve this problem, our company organizes supervision, supervision, professional staff and construction units to work out the pipe layout so as to ensure that the rubber ball washing system is operating normally. Vacuum system equipment installation unit vacuum tightness, seriously affect the unit's vacuum. The commissioning of the unit after it was put into operation to check the leakage of the vacuum system's upstream water was constrained by many conditions. Such as the turbine cylinder temperature, vacuum system equipment, such as the impact of insulation, leak detection, leak detection and other factors. The best way to ensure the vacuum tightness of the new unit is to check leaks in the system after installing the system. The two units of our company carried out multiple leak check on the water and discovered that many leaks must be processed again after the leaks are processed until there is no leak. When installing, carefully check the metering and measuring points of the vacuum system. In the case of a machine with a high water level leak detection, it was found that a temperature measuring point reserved at the upper part of the lower pressure lower cylinder is not sealed. If it is not discovered in time, the vacuum of the unit will be seriously affected.
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