The check valve is only a valve that guides the water flow in one direction and is not an effective device to prevent backflow pollution. This concept is the principle of using a check valve or a pipe backflow preventer. The pipeline backflow preventer has the function of a check valve, but the check valve does not have the function of a pipeline backflow preventer, so after the pipeline backflow preventer is provided, there is no need to set a check valve. China check valve manufacturer shares with you.
Check valves are required in the following cases:
1. Only on the inlet pipe directly connected from the urban water supply pipe.
2. A non-return valve should be installed on the closed water heater or the water inlet pipe of the water equipment. Since the volume of hot water units used in residences is small, the possibility of backflow occurs when there is no hot water circulation. Therefore, there is no hot water unit with a storage volume of no more than 200L in the house. valve.
3. When there is one water inlet and outlet pipe for the water tank and water tower, in order to prevent water from entering the bottom, a check valve should be installed on the pipe section of the water outlet at the bottom. It should be noted that when the check valve enters the water tank (tower), the check valve is in an unstable pressure state due to the effect of the three-way jet, which will cause the flap (core) to vibrate. Therefore, the check valve should be vibration-isolated.
The selection of the check valve type should be determined according to factors such as the installation location of the check valve, the water pressure before the valve, the requirements for the sealing performance after closing, and the size of the water hammer caused when closing, and should meet the following requirements:
1. For parts with small water pressure in front of the valve, swing check, ball and shuttle check valves should be selected;
2. After closing, the parts with tight sealing performance requirements should choose the check valve with closing spring;
3. For parts that require weakening to close the water hammer, a quick-closing muffler check valve or a slow-closing check valve with a damping device should be used;
4. The disc or spool of the check valve should be able to close by itself under the action of gravity or spring force;
5. The minimum pressure of the pipe network or the minimum water level of the water tank should be able to automatically open the check valve.
6. When the water in and out of the water tank and water tower are the same pipeline, it is not suitable to use the swing-type or lifting type with large vibration.
Our company also provides Acid Resistance Dual Plate Check Valve.