Working Principle and Structural Characteristics of Micro-resistance Slow-closing Check Valves
Ordinary
check valves close quickly, which is easy to produce water hammer, causing sudden pressure rise, damaging pipelines and equipment, and causing loud noise. The
micro-resistance slow-closing check valve solves the problem caused by the quick closing of the common check valve. It is used in the direct water supply and drainage system of pumps in industrial and mining enterprises and high-rise buildings, which can reduce the occurrence of water hammer and achieve the effect of safe closing.
Structural characteristics of micro-resistance slow-closing check valve
One valve is installed before and after the valve to facilitate maintenance. A filter is installed in front of the valve to prevent impurities in the pipeline system from entering the
check valve. The
micro-resistance slow-closing check valve shall be installed horizontally. If the valve is installed in the well, a certain maintenance space should be reserved. Automatic exhaust valves shall be installed on pipelines according to relevant specifications to ensure the continuous flow of water column. The valve should not be placed in the environment below 0℃.
Working principle of micro-resistance slow closing check valve
When the water pump starts, the pressure at the inlet end of the valve urges the flap to open quickly against the spring force. At the same time, the medium at the inlet end of the main valve enters the upper chamber of the diaphragm through the needle valve and the
check valve. Adjust the opening of the needle valve, so that the medium entering the upper cavity of the diaphragm acts on the diaphragm pressure plate, and produces a reaction force on the valve disc to ensure that the valve disc is opened slowly. Adjust the opening of the needle valve at the inlet end of the main valve, controlling the opening speed of the valve, and ensure that the opening time of the main valve is longer than the starting time of the pump motor, so as to start the pump under light load and prevent the motor from starting too much current.
When the water pump is turned off, the pressure at the inlet end of the valve suddenly decreases, and the valve flap will suddenly be closed under the action of the pressure at the outlet end, so that the pressure at the outlet end of the valve suddenly rises. At this time, it is easy to produce water hammer phenomenon, causing damage to pipeline and equipment behind the valve, and producing great noise. Since a backflow system is installed at the outlet end of the valve, the medium behind the valve enters the upper chamber of the diaphragm through the ball valve, and the medium cannot enter the inlet end due to the non-return action of the check valve. At the same time, the lower chamber of the diaphragm is also full of medium. Although the pressure of the medium in the upper chamber urges the valve flap to close, the medium in the lower chamber cannot be quickly discharged under the throttling action of the small hole on the diaphragm seat, resulting in a buffering process, which prevents the closing speed of the valve flap, achieves the effect of slow closing and silence, and avoids the water hammer phenomenon. By adjusting the opening degree of the ball valve, the closing speed of the valve flap (that is, the closing time of the valve) can be effectively controlled.
The
micro-resistance slow closing check valve has the technical characteristics of slow opening and slow closing and elimination of water hammer, which realizes the start of pump under light load and prevents the generation of water hammer when the pump is stopped. After starting the pump motor, the valve will automatically open and close according to the operating rules of the pump.