Selection and location of valves

1、 Valve selection and setting position:

(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, the stop valve should be used. When the pipe diameter is greater than 50mm, gate valve and butterfly valve shall be used

2. When the flow and water pressure need to be adjusted, the regulating valve and stop valve should be used

3. Ram valve should be used for parts with small water resistance (such as on water pump suction pipe)

4. Gate valve and butterfly valve shall be used on the pipe section where the flow needs to flow in two directions, and stop valve shall not be used

5. Butterfly valve and ball valve should be used for the parts with small installation space

6. Stop valve should be used for the pipe section which is often opened and closed

7. Multi function valve should be used on the outlet pipe of water pump with large caliber

(2) Valves shall be provided at the following parts of the water supply pipeline:

1. The water supply pipeline in residential quarters is from the pipe section of municipal water supply pipeline

2. The node of outdoor ring pipe network in residential quarter shall be set according to the requirements of separation. If the annular pipe section is too long, it is advisable to set up sectional valve

3. The starting end of branch pipe or the starting end of the connecting pipe from the main water supply pipe of residential quarters

4. Household pipe, water meter and each branch riser (the bottom of riser and the upper and lower part of vertical annular pipe network riser)

5. The main pipe of ring pipe network and connecting pipe through branch pipe network

6. The starting point of the distribution pipe connected from the indoor water supply pipe to the household, public toilet, etc. shall be set when the distribution point on the distribution branch pipe is more than 3

7. Water outlet pipe of water pump, suction pump of self filling pump

8. Water inlet and outlet pipes and discharge pipes of water tanks

9. Water inlet and make-up pipes for equipment (such as heater, cooling tower, etc.)

10. Distribution pipes for sanitary appliances (such as large, urinals, wash basins, showers, etc.)

11. Some accessories, such as automatic exhaust valve, pressure relief valve, water hammer eliminator, pressure gauge, sprinkler, etc., pressure reducing valve and backflow preventer, etc

12. The lowest part of water supply network should be equipped with water release valve

 

(3) Generally, check valve shall be selected according to the installation position, water pressure in front of valve, sealing performance requirements after closing and water hammer size caused by closing

1. When the water pressure is in front of the valve, swing, ball and shuttle check valves should be selected

2. When the sealing performance after closing is tight, it is advisable to select the check valve with closing spring

3. When it is required to weaken the closing water hammer, it is advisable to select the quick closing silencing check valve or the slow closing check valve with damping device

4. The valve break or valve core of check valve shall be able to close by itself under the action of gravity or spring force

(4) Check valves shall be provided on the following sections of the water supply pipeline:

On the inlet pipe; on the closed water heater or water equipment; on the water pump outlet pipe; on the outlet pipe of the water tank, water tower and highland pool where the water inlet and outlet pipes share one pipe.

Note: the pipe section with pipe backflow preventer does not need to install check valve.

(5) Exhaust devices shall be provided at the following parts of the water supply pipeline:

1. For intermittent water supply network, automatic exhaust valve shall be set at the end and highest point of the pipe network

2. The water supply network has obvious fluctuation and accumulation of air in the pipe section, and automatic exhaust valve or manual valve has been set at the peak point of the section to exhaust

3. When the automatic air pressure water tank is used for air pressure water supply device, the highest point of the water distribution network shall be equipped with automatic exhaust valve


Post time: Mar-24-2021

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