ZDL series automatic recirculation pump protection valve

What is ZDL Series Automatic Recirculation Pump Protective Valve

ZDL series automatic circulation pump protection valve is a pump protection device. It automatically protects the centrifugal pump (especially the hot water medium) from partial cavitation damage and instability that may occur in the pump body during low load operation. Once the pump flow rate falls below the preset rate, the bypass fully opens to ensure the minimum flow required by the pump. Even if the main route is completely closed, that is, the minimum traffic can be automatically cycled through the bypass. The pressure is reduced by an integrated multistage throttle reducing valve in the bypass. The ZDL series has a bypass suitable for moderate differential pressure up to 6MPa, the specific choice is factory determined. The unique L-shaped sidelight eliminates noise generated by high-speed flowing media and prevents cavitation.

What are the features of ZDL Series automatic recirculation pump protective valves?

Porous cage bypass, low noise, suitable for medium and low pressure conditions.

Forged valve body, can choose carbon steel or stainless steel material.

Standard bypass with check function, maximum working pressure difference up to 6MPa.

The main road check structure with Venturi runner ADAPTS to complex working conditions.

Pressure rating PN16-PN100, caliber DN25-DN500.

You can optionally add the manual bypass operation function for use when faults occur.

ZDL series automatic recirculation valve principle

The main disc check cone of the automatic recirculation valve will automatically move to a certain position according to the sensed main flow. At the same time, the main valve disc drives the bypass valve lever, transfers the action of the main valve disc to the bypass, controls the position of the bypass valve disc through the lever, changes the throttling area of the bypass, and thus controls the flow through the bypass. When the main disc returns to the seat closed position, all flow is returned via bypass. When the main disc is raised to the top position, the bypass is completely closed and all pump flow flows to the process system. The valve integrates four functions in one.

Flow sensing: The main disc of the automatic recirculation valve automatically senses the main flow rate in the process system and determines the position of the main disc and bypass disc based on this flow rate.

Recirculation control: The automatic recirculation valve can draw the minimum flow required for normal operation of the pump into the storage device through bypass, adjust the H-Q characteristics of the pump, and achieve recirculation.

Bypass multistage decompression: The bypass control system can reduce the reflux medium from the high pressure at the pump outlet to the low pressure suitable for the reflux storage device with low noise and low wear

Check: The automatic recirculation valve also acts as a check valve to prevent the liquid from flowing back into the pump body. Standard bypass with check function.

Other bypass sizes can be made according to requirements; The maximum bypass flow depends on the maximum Kv value.