HVAC ventilation pipe valve selection

HVAC pipe valve selection design 1, chilled water unit, cooling water import and export design butterfly valve; 2, before the pump butterfly valve, filter, pump check valve, butterfly valve; Differential bypass valve; 4, set, diverter into, back to the butterfly valve 5, the level of the butterfly valve; 6, air handling unit gate valve, filter, electric two or three-way valve 7, fan coil valve Electric two-way valve) Note: When the butterfly valve is generally used, the handle type butterfly valve (D71X, D41X) is adopted when the diameter is less than 150mm; the worm gear type butterfly valve (D371X, D341X) is adopted when the diameter is larger than 150mm. Valves used in HVAC valves: 1, pressure reducing valves, balancing valves and other must be added bypass valve; 2, fully open and fully closed with the best ball valve, gate valve; 3, HVAC pipe to minimize the use of globe valve; 4, Valve resistance calculation should pay attention; 5, electric valve must be selected. Valve selection principle 1, the need to adjust the flow, water pressure, should adopt the control valve, globe valve; 2, requiring a small flow resistance parts (such as the pump suction pipe), gate valve should be adopted; 3, Small installation space, should adopt the butterfly valve, ball valve; 4, the flow of water to be bidirectional flow of pipe, shall not use the cut-off valve; 5, larger caliber pump, outlet pipe should be multi-purpose valve. Check valve setting requirements: 1, the introduction of the tube; 2, a closed water heater or water equipment inlet pipe; 3, the pump outlet pipe; 4, out of the water pipe with a pipe tank, water tower, high ground pool On the water pipe section. Note: Pipe backflow preventer equipped with pipe sections, no need to install the check valve. Check valve valve type selection: should be based on the check valve mounting site, the valve before the water pressure, closed after the closure of the performance requirements and the closure of the water hammer caused by the size and other factors to determine, should meet the following requirements: 1, the valve before the water Small pressure parts, should use swing check valve, ball check valve and shuttle check valve. 2, after the closure of the strict requirements of tightness of the site, should use a closed spring check valve. 3, requiring the weakening of the water hammer off the site, should choose to quickly close the silencer check valve or damping device with slow closing check valve. 4, check valve valve breaking or valve core, should be able to force itself in the gravity or spring off. The following parts of the water supply pipe should be set exhaust device: 1, intermittent cycle of the water supply network, the end of the pipe network and the highest point should be equipped with automatic exhaust valve. 2, there is a clear ups and downs of the water supply pipe network of air accumulation, has been set in the peak of automatic exhaust valve or manual valve exhaust. 3, pressure water supply device, when using automatic gas pressure tank, the highest point of its distribution network should be set automatically exhaust valve.