Globe ball gate butterfly check valve selection & setting location

May 09, 2020
Industry News

(1) The valves used in the water supply pipeline are generally selected according to the following principles:

1. When the pipe diameter is not more than 50mm, a globe valve should be used. When the pipe diameter is more than 50mm, a gate valve or a butterfly valve is used.
2. When the flow and water pressure need to be adjusted, a regulating valve and or a globe valve should be used.
3. A gate valve should be used in parts that require small flow resistance (such as on the suction pipe of the pump).
4. Gate valves and butterfly valves should be used on the pipe sections where the water flow needs to flow in both directions, and globe valves should not be used.
5. Butterfly valve and ball valve should be used in the small installation space.
6. On the pipeline section that is frequently opened and closed, a globe valve should be used.
7. A multi-function valve should be used on the outlet pipe of a large-diameter pump.

(2)The following parts on the water supply pipeline shall be provided with valves:

1. The water supply pipeline in the residential area should be provided with a valve on the inlet pipe section of the municipal water supply pipeline.
2. Tube joints of outdoor annular pipeline network in the residential area should be equipped with valves according to the separation requirements. When the annular pipe section is too long, it is advisable to install valves in sections.
3. The beginning of the branch pipe or the building unite pipe connected from the water supply pipe in the residential area.
4. Inlet pipe, water meter and branch stand pipes (bottom of stand pipes, upper and lower ends of vertical stand pipes in annular pipeline network.
5. The branch pipe of the annular pipeline network and the connecting pipe through the branch pipeline network.
6. The beginning of the water distribution pipe from the indoor water supply pipe to the residents and public toilets, and the valve should be set when there are 3 or more water distribution points on the water distribution branch.
7. Outlet pipe of water pump, suction pump of self-priming water pump.
8. Inlet and outlet pipes and drain pipes of the water tank.
9. Inlet water supply pipe of equipment (such as heater, cooling tower, etc.).
10. Water distribution pipes for sanitary appliances (such as large and small urinals, washbasins, showers, etc.).
11. Some accessories, such as the front of automatic exhaust valve, pressure relief valve, water hammer eliminator, pressure gauge, sprinkler, etc., the front and rear of pressure relief valve and backflow preventer, etc.
12. The lowest part of the water supply pipeline should be equipped with a drain valve.

(3) A check valve should generally be selected according to factors such as its installation location, the water pressure in front of the valve, the sealing performance requirements after closing, and the size of the water hammer caused during closing.

1. When the water pressure before the valve is small, swing check valve, ball check valve or shuttle check valve should be used.
2. When the sealing performance requirements after closing are strict, it is advisable to choose a check valve with a closing spring.
3. When it is required to weaken and close the water hammer, it is advisable to choose quick-closing muffler check valve or slow-closing check valve with damping device.
4. The valve flap or spool of the check valve should be able to close by itself under the action of gravity or spring force.

(4) Check valves should be installed on the following sections of the water supply pipeline:

On the inlet pipe; on the inlet pipe of the 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 with a pipeline.

Note: It is not necessary to install a check valve for the pipe section equipped with a pipeline backflow preventer.

(5) The following parts of the water supply pipeline shall be provided with exhaust devices:

1. For the water supply pipe network used intermittently, the end and the highest point of the pipe network should be equipped with an automatic exhaust valve.
2. When there is a pipe section with obvious undulation and accumulation of air in the water supply network, an automatic exhaust valve or a manual valve should be set to exhaust at the peak point of the section.
3. As for pressurized-type water supply unit, when using automatic air supplement pressurized water tank, the highest point of its water distribution network should be equipped with an automatic exhaust valve.