How to Select Water Supply And Drainage Pipeline Valves

Valve is the control component of fluid transportation system, which has the functions of cut-off, regulation, diversion, prevention of countercurrent, pressure stabilization, shunt or overflow relief. The valves used in fluid control system, from the simplest stop valve to various valves used in extremely complex automatic control system, have many varieties and specifications. But how to select the right valves for water supply and drainage pipeline?

Valves

Selection and Setting Position of Valve

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

  • When the pipe diameter is not more than 50mm, the stop valve should be used. And gate valve and butterfly valve shall be used when the pipe diameter is greater than 50mm;
  • When the flow and water pressure need to be adjusted, the regulating valve and stop valve should be used;
  • If the water resistance is small (such as on the water pump suction pipe), the ram valve should be used;
  • 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;
  • Butterfly valve and ball valve should be used for the parts with small installation space;
  • Stop valve should be used for the pipe section which is often opened and closed;
  • Multi-function valve should be used on the outlet pipe of water pump with large caliber.

2. The following parts of the water supply pipeline shall be provided with valves

  • The water supply pipeline of residential area is from the leading in pipe section of municipal water supply pipeline;
  • The node of outdoor loop pipe network in residential area should be set according to the separation requirements. When the annular pipe section is too long, the sectional valve should be set;
  • The starting end of the branch pipe or the household pipe connected from the main water supply pipe in the residential area;
  • The inlet pipe, water meter and branch risers (the bottom of the riser, the upper and lower ends of the riser of the vertical annular pipe network);
  • The main pipe of the annular pipe network and the connecting pipe through the branch pipe network;
  • When there are three or more water distribution points on the water distribution branch, the starting point of the water distribution pipe from the indoor water supply pipe to the household and public toilet shall be set;
  • The outlet pipe of the water pump and the suction pump of the self filling water pump;
  • The water inlet and outlet pipes and drain pipes of the water tank;
  • Water inlet make-up pipe of equipment (such as heater, cooling tower, etc.);
  • Distribution pipes of sanitary appliances (such as toilet, urinal, washbasin, shower, etc.);
  • Some accessories, such as automatic exhaust valve, pressure relief valve, water hammer eliminator, pressure gauge, sprinkler, pressure reducing valve and backflow preventer, etc;
  • The lowest part of the water supply network should be equipped with a drain valve.

3. Check valve should be selected according to its installation position, water pressure in front of the valve, sealing performance requirements after closing and water hammer caused by closing

  • When the water pressure in front of the valve is small, the swing check valve, ball check valve and shuttle check valve should be selected.
  • When the sealing performance after closing is strict, check valve with closing spring should be selected.
  • When it is required to weaken the shut-off water hammer, the quick closing silencing check valve or the slow closing check valve with damping device should be selected.
  • The valve break or spool of check valve shall be able to close automatically under the action of gravity or spring force.

Check Valve

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

  • On the inlet pipe;
  • On the inlet pipe of closed water heater or water using equipment;
  • Water pump outlet pipe;
  • The inlet and outlet pipes share the same pipe in the water tank, water tower and outlet pipe section of highland pool. Note: it is not necessary to install check valve in the pipe section with pipe backflow preventer.

5.The following parts of the water supply pipeline shall be equipped with exhaust devices:

  • Automatic exhaust valve shall be set at the end and the highest point of intermittent water supply network.
  • For the pipe section with obvious fluctuation and air accumulation in water supply network, automatic exhaust valve or manual exhaust valve has been set at the peak point of the section.
  • For the pneumatic water supply device, when the automatic air supply type pneumatic water tank is adopted, the highest point of the water distribution network shall be equipped with an automatic exhaust valve.

6.According the transmission modes to select values.

Valve control can adopt a variety of transmission modes, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electromagnetic hydraulic, electro-hydraulic, pneumatic, spur gear, bevel gear drive, etc; Under the action of pressure, temperature or other forms of sensing signals, the valve can act according to the predetermined requirements, or simply open or close without depending on the sensing signal. The valve depends on the driving or automatic mechanism to make the lifting, sliding, swinging or rotary movement of the opening and closing parts, so as to change the size of its flow channel area to realize its control function.

Extended reading: The Advantages and Disadvantages of Various Valves

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