First, the multi-function pump control valve Introduction Multi-function pump control valve is a new type of hydraulic control valve, a valve to replace the electric butterfly (gate) valve, check valve and water hammer eliminator three devices. It can automatically open the pump when the slow opening, closing the pump when the closure and slow closure, without any electrical control and other power and manpower, but also without the hydraulic device. The main advantages of the multi-function pump control valve are: (1) no operational control required. When using the pump start and stop the valve before and after the water pressure difference as a control power, with the opening and closing of the pump automatically opens and closes the function. (2) Valve opening and closing movements can effectively prevent accidents caused by water hammer pressure wave. According to field use survey and measured, stop the pump water hammer pressure peak at 1.3 times the working pressure. (3) Without on-site commissioning, a wide range of applicable conditions. (4) basically no maintenance. As a valve to replace the three valves, maintenance and repair workload greatly reduced. (5) resistance loss is small. The use of streamlined, wide body design, resistance loss than the same kind of foreign products to reduce more than 50%, such as DN200 products in the v = 2m / s economic flow conditions, multi-functional pump control valve loss of 0.7m, while foreign similar products 1.5m. Second, the structure and working principle of multi-function pump control valve 1 Structure Multi-function pump control valve structure shown in Figure 1, by the main valve and external accessories. The main valve includes the valve body, the main valve plate, slow closing valve plate, valve stem, seat and diaphragm controller (including valve cover, diaphragm seat, diaphragm, diaphragm pressure plate): external accessories control valve, filter , Emptying valve, micro check valve. One micro-check valve is a special accessory, in its non-return direction with a current limiting hole. See Figure 2 for installation. 2 Working principle Before starting the pump, the valve outlet pressure on the role of the main valve plate, the valve is closed, while the diaphragm controller connected to the pressure on the water chamber, the lower chamber and the valve inlet is connected to the low pressure. Pump starts, the valve inlet pressure gradually increased, while pressure water through the valve inlet side of the connecting tube slowly into the diaphragm controller cavity, the main valve plate to achieve a slow opening, the opening speed can be adjusted by the control valve. When the pump stops and the pressure of the valve is reduced, when close to zero flow, the main valve plate closes rapidly under its own gravity. As the pressure at the inlet of the valve is reduced, the pressure water at the outlet of the valve enters the upper chamber of the diaphragm controller through the connecting pipe, the lower chamber water is pressed back to the inlet of the valve through the connecting pipe at the inlet of the valve, the slowly closing valve plate is slowly closed, Adjust by control valve. The closure of the main valve plate and the slow closure of the slow closing plate complies with the two-phase closing rule, which can effectively eliminate the water hammer. Third, the multi-function pump control valve of several technical issues 1 connecting pipe parts micro-check valve is to ensure that the valve opening time is greater than the motor start-up time, so that light motor start; the same time to avoid the valve opening too fast and Lead to start pumping water hammer. Valve opening time by the control valve according to field conditions pressure settings. The control valve can adjust the water flow speed of the upper and lower chambers of the diaphragm controller so as to adjust the slow closing time; the diaphragm controller can be repaired when closed; and the valve can be manually operated during the normal operation of the water pump to open and close the valve. The filter is to ensure the cleanliness of the water in the upper and lower chambers of the diaphragm controller. As the valve in a process of opening and closing the water is reciprocating access, itself has the role of backwash, it can also be used for poor medium conditions. 2 The elimination of water hammer valve characteristics From the principle of destructive water hammer we can see that there are two main factors to reduce the water hammer boost: (1) just before cutting off the water flow velocity v as small (close to zero) Close the main valve plate; (2) make the valve closing time t is water Hammer phase u = 2L / α (α - pressure wave transmission speed, m / s; L - pipe length, m) 5-10 times The actual water hammer pressure, h, can be limited to a safe range, thereby eliminating damaging water hammer hazards. The opening degree of the main valve plate of the multi-purpose pump control valve is determined by the impact force of the water flow in the pipeline. The main valve plate opening degree is high when the flow rate is high: the valve plate opening degree is small when the flow rate is reduced: when the flow rate approaches zero, Board closed. The whole process is consistent with the elimination of the principle of water hammer close fast, so the elimination of water hammer works well. Multifunctional pump control valve slow closing valve plate closed, the diaphragm must be formed on the lower chamber pressure difference before it can be achieved, that is, the main valve plate is closed, slow closing valve plate can only be closed, it is impossible to produce slow closure and Speed ​​closed synchronization phenomenon. 3 valve resistance characteristics In order to reduce water flow resistance, reducing the design of the main valve plate weight, while using a streamlined spacious body design. The Hunan Hydraulic Machinery Quality Supervision authorized station test, DN200 multi-function pump control valve resistance coefficient of about 3.8, while the same specifications of the pipe swing check valve resistance coefficient of 5.5. 4 diaphragm design diaphragm quality is a direct impact on valve performance and service life of the key components, after a variety of screening, the selection of neoprene as raw material, the middle of the nylon fiber network to strengthen; by Hunan Rubber Quality Supervision authority Station testing, 650,000 fatigue fatigue without rupture, can be used for more than 10 years. 5 Maintenance No other external hydraulic or electric components, the basic maintenance-free, and the use of a wide bonnet, valve components can be removed completely, easy maintenance. IV Conclusion After field use of proof, multi-function pump control valve can effectively eliminate destructive water hammer, water supply system to improve the safety and reliability of significant features, and ease of commissioning and installation, ease of operation and management, less maintenance, in line with The requirements for automation, mechanization and modernization of water supply equipment in the Plan for Technological Progress and Development in the Urban Water Supply Industry in 2000 are new valve products that are upgrading and replacing pumping stations.
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