Valves selection
Valves selection
Valves used on water supply pipelines are generally selected according to the following principles:
1.When the pipe diameter is not more than 50mm, a stop valve should be used; when the pipe diameter is more than 50mm, a gate valve or butterfly valve should be used.
2.When the flow and water pressure need to be adjusted, a regulating valve and a globe valve should be used.
3. For parts that require low flow resistance (such as on the suction pipe of a pump), gate valves should be used.
4. Gate valves and butterfly valves should be used on pipe sections where water flow needs to flow in both directions, and stop valves should not be used.
5. Butterfly valves and ball valves should be used in places where the installation space is small.
6. It is advisable to use shut-off valves on pipe sections that are frequently opened and closed.
7, a multi-function valve should be used on the outlet pipe of the pump with a larger diameter.
Valves should be installed at the following locations on the water supply pipeline:
1. The water supply pipeline of the residential quarter is from the introduction pipe section of the municipal water supply pipeline.
2. The nodes of the outdoor loop pipe network of the residential quarter should be set up according to the separation requirements. When the annular pipe section is too long, a segmented valve should be installed.
3. The beginning of the branch pipe connected to the main water supply pipe of the residential area or the beginning of the household pipe.
4. Household pipes, water meters and branch risers (the bottom of the riser, the upper and lower ends of the riser of the vertical ring pipe network)
5. The branch pipes of the ring-shaped pipe network and the connecting pipes through the branched pipe network.
6. The end of the water distribution pipe connecting the indoor water supply pipe to the households, public toilets, etc., and the water distribution point on the water distribution branch pipe is set when there are 3 or more.
7. Outlet pipe of water pump, suction pump of self-filling water pump
8. The inlet and outlet pipes and drain pipes of the water tank
9. The water inlet and make-up pipes of equipment (such as heaters, cooling towers, etc.)
10. Water distribution pipes for sanitary appliances (such as urinals, washbasins, showers, etc.)
11. Some accessories, such as automatic exhaust valve, pressure relief valve, water hammer eliminator, pressure gauge, sprinkler, etc., before and after pressure reducing valve and backflow preventer, etc.
12. A drain valve should be installed at the lowest point of the water supply network.
Check valves should generally be selected according to factors such as their installation location, water pressure before the valve, sealing performance requirements after closing, and the size of the water hammer caused by closing
1. If the water pressure in front of the valve is small, it is advisable to use swing, ball and shuttle check valves
2. When the airtight performance after closing is tight, a check valve with closing spring should be selected
3. When it is required to weaken the shut-off water hammer, a quick-closing muffler check valve or a slow-closing check valve with a damping device should be selected
4. The valve break or spool of the check valve should be able to close automatically under the action of gravity or spring forceCheck valves shall be provided on the following pipe sections of the water supply pipeline:
On the introduction pipe; on the inlet pipe of a closed water heater or water equipment; on the outlet pipe of the water pump; on the outlet pipe section of the water tank, water tower, and highland pool where the inlet and outlet pipes are combined.
Note: The pipe section equipped with the pipe backflow preventer does not need to install a check valve.Exhaust devices should be installed in the following parts of the water supply pipeline:
1. For the water supply pipe network used intermittently, the end and highest point of the pipe network should be equipped with automatic exhaust valves
2. There are obviously undulating pipe sections in the water supply network that accumulate air, and automatic exhaust valves or manual valves have been set up at the peak of this section.
3. Air pressure water supply device. When automatic air-supply air pressure water tank is used, the highest point of the water distribution pipe network should be equipped with an automatic exhaust valve
