500X Pressure Holding/Release Valve

The 500X Pressure Holding and Relief Valve comprises a main valve, a relief/holding pilot valve needle valve, a ball valve, a micro-filter, and a pressure gauge, forming a hydraulically controlled piping system. The 500X Pressure Holding and Relief Valve operates automatically via hydraulic force, functioning both as a relief valve and a pressure holding valve. When used as a relief valve, it maintains supply line pressure below a preset safety threshold. As a pressure holding valve, it sustains upstream pressure above the set value, preserving supply pressure upstream of the main valve. For sizes DN400 and above, piston-type safety relief valves are recommended.
The 500X Pressure Holding and Relief Valve utilizes self-powered hydraulic control, requiring no additional devices or energy sources. It offers simple maintenance and multi-functional operation.
The 500X Pressure Holding and Relief Valve is widely used in water supply pipeline systems for high-rise buildings, residential are

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500X Pressure Holding/Release Valve Working Principle

1. As a relief valve: When the relief/pressure-holding pilot valve is adjusted to the relief state, water flows through the needle valve, main valve control chamber, ball valve A, relief/pressure-holding pilot valve, and ball valve B toward the outlet, keeping the main valve open. When the inlet pressure exceeds the safety set point of the pressure relief/holding pilot valve, the pressure relief pilot valve automatically opens. Water is partially discharged through ball valve C to relieve pressure in the pipeline. The pressure relief valve automatically closes when pressure returns to the safety set point. When functioning as a pressure relief valve, all ball valves remain normally open.

2. As a pressure-holding valve: When the relief/pressure-holding pilot valve is adjusted to pressure-holding mode, the pilot valve closes whenever the main valve inlet pressure falls below the pilot valve set point. This primarily controls pressure buildup in the main chamber, closing the main valve. Only when the upstream supply pressure exceeds the pilot valve's set pressure will the pressure-holding pilot valve open. Water from the control chamber is then discharged through the ball valve to the outlet, causing the control chamber pressure to drop. The main valve opens to begin water supply, thereby maintaining the upstream pressure. When used as a pressure-holding valve, ball valve C remains closed or is replaced with a plug.