User Manual for Air Discharge Check Valve (Pump Protection Valve) H48Y
catalogue
 
Usage and Performance Specifications .2
Working principle .2
Advantages: .3
The lever principle of automatic recycling .4
Design specifications .4
Valve size .5
Component materials .6
Installation: .6
Maintenance, upkeep, and use .6
Usage and Performance Specifications
Pump protection valve (also known as minimum flow valve, automatic control valve, automatic recirculation valve, automatic reflux valve) is used to prevent damage to centrifugal pumps caused by overheating, severe noise, instability, and cavitation when operating below load. As long as the flow rate of the pump is below a certain value, the bypass return port of the valve will automatically open to ensure the minimum flow rate required by the liquid pump.
Working principle
The pump protection valve is connected to the outlet position of the pump and, like a check valve, opens the valve disc by the thrust of the medium. Under the condition of constant pressure in the main channel, the flow rate of the main channel is different, and the opening of the valve disc is different. The main valve disc will be determined at a certain position, and the valve disc of the main circuit will transmit the action of the main valve disc to the bypass through a lever to achieve the automatic switching state of the bypass.

Due to low pipeline pressure, this valve can only be installed vertically and cannot be installed horizontally
Advantage
Pump protection valve (also known as minimum flow valve, automatic control valve, automatic recirculation valve, automatic reflux valve, air discharge check valve) is a valve that integrates multiple functions.
Has the following significant advantages:
1. The automatic recirculation valve is a self operated control valve, and the lever function automatically adjusts the bypass opening according to the flow rate (system flow regulation). It is a completely mechanical structure that relies on flow control valves and does not require additional energy.
2. The bypass flow can be automatically adjusted and controlled, and the overall operation of the valve has high economy.
3. Both the main channel and bypass are equipped with check valves.
4. Three way T-shaped structure, suitable for recirculation pipelines.
5. Bypass does not require continuous flow, reducing energy consumption.
6. Multi functional integration reduces design workload.
7. In terms of early product procurement, installation and debugging, as well as later maintenance, it has significant cost advantages, reducing installation and maintenance costs, and overall costs are lower than traditional control valve systems.
8. Reduce the likelihood of faults occurring, minimize the possibility of high-speed fluid causing faults, and eliminate cavitation issues and electrical wiring costs.
9. Stable operation of the pump can still be ensured under low flow conditions.
10. The protection of the pump only requires one valve and does not require any additional components. As it is not affected by faults, the main channel and bypass become a whole, making it easy to maintain.
The lever principle of automatic recirculation valve
When the main valve disc is opened, the valve disc drives the lever action, and the lever force closes the bypass. When the flow rate of the main pipeline decreases and the main valve disc cannot be opened, the main valve disc will return to the sealing position, causing the main channel to close. The valve disc will once again drive the lever action, opening the bypass and allowing water to flow from the bypass to the water storage tank. Under the pressure of the water storage tank, the water flows to the inlet of the pump for a recirculation action, which protects the pump.
Design Specification
Design and Manufacturing Standards: ASME B16.34 JB/T3595 GB/T12235;
Structural length standard: ASME B16.10 GB/T12221 or according to user requirements.
Flange end standard: ASME B16.5 GB/T9112 JB/T79 GB/T20592 or as provided by the user.
Testing and Inspection Standards: API598 JB/T3595 JB/T9092
Pressure and temperature rating: ASME B16.34 JB/T3595 GB/T12224
6、 Valve size
The following are valve sizes for some pressures and diameters, while other pressure and diameter sizes are designed according to standards or user requirements.

7、 Component Name
Valve body: WCB A105
Internal components: WCB stainless steel
Other forging and casting materials for valve bodies and internal components can be provided according to user needs, and the selection of valve body and internal component materials is determined by the pressure and temperature conditions of use.
Install
The automatic recirculation valve should be installed at the outlet of the pump, preferably near the protected centrifugal pump. The distance between the pump outlet and the valve inlet should not exceed 1.5 meters to prevent low-frequency water hammer caused by liquid pulsation. The flow direction is from bottom to top.
Maintenance, upkeep, and usage precautions
1. Valves should be stored in a dry and ventilated room, and both ends of the valve should be blocked.
2. Valves stored for a long time should be regularly inspected and cleaned of dirt. Special attention should be paid to the cleanliness of the sealing surface to prevent damage.
3. Before installation, carefully check whether the valve markings match the usage requirements.
4. Before installation, the valve cavity and sealing surface should be checked. If there is dirt, it should be wiped clean with a cleaning cloth.
5. Valves should be regularly inspected after use, checking the sealing surface of the main pipeline and the sealing surface of the bypass. If damaged or ineffective, it should be repaired or replaced in a timely manner.