ZDT Automatic Recirculation Valve

Introduction to ZDT Automatic Recirculation Valve:

The ZDT automatic recirculation pump protection valve is a pump protection device. It automatically protects the centrifugal pump (especially when transporting hot water media) from potential partial cavitation damage and instability during low-load operation. Once the pump flow is lower than the preset flow, the bypass opens to ensure the minimum required flow for the pump. Even if the main line is completely closed, that is, the main line flow is zero, the minimum flow can still be automatically circulated through the bypass. The pressure is reduced by the integrated multi-stage throttling and pressure reducing valve in the bypass. 

The ZDT automatic recirculation valve has a large-diameter bypass. This valve is used for larger bypass flow rates, with a maximum pressure difference of up to 4 MPa. 

 Working Principle:

Based on the different main flow rates sensed, the main valve flap check cone will automatically move to a certain position. At the same time, the main valve flap drives the bypass valve stem, transmitting the action of the main valve flap to the bypass. By controlling the position of the bypass valve flap, the throttling area of the bypass is changed, thereby controlling the flow of the bypass. When the main valve flap returns to the valve seat and closes, all the flow returns through the bypass. When the main valve flap rises to the top position, the bypass is closed, and all the pump flow flows to the working system.

This valve integrates four functions:

1. Flow sensing: The main valve flap can automatically sense the main flow in the process system, thereby determining the positions of the main valve flap and the bypass valve flap.

2. Recirculation control: The minimum flow required for the normal operation of the pump can be吸入 into the storage device through the bypass， adjusting the pump H-Q characteristics， and achieving recirculation.

3. Multi-stage bypass pressure reduction： The bypass control system can reduce the high-pressure return medium from the pump outlet to a suitable low-pressure for the return to the storage device with low noise and low wear.

4. Check valve： It also has the function of a check valve， preventing liquid from flowing back into the pump body. The ZDT bypass check valve is an optional function. 

●Features:

◇ Simple structure, reliable and stable operation, with only a few moving parts.

◇ Easy to install, can be installed vertically or horizontally at the pressure outlet of the pump.

◇ Large bypass flow rate, up to 60% of the main flow, and the KV value can be adjusted.

◇ The maximum working pressure difference of the bypass is up to 4 MPa (the bypass check valve function can be selected).

◇ Suitable for water, oil, methanol and other liquid media. The working temperature ranges from -196℃ to +300℃.

The ZDT automatic recirculation pump protection valve is a pump protection device. It automatically protects the pump body from potential partial cavitation damage and instability that may occur when the centrifugal pump (especially when conveying hot water media) operates at a low load. Once the pump flow is lower than the preset flow, the bypass opens to ensure the minimum required flow of the pump. Even if the main line is completely closed, that is, the main line flow is zero, the minimum flow can still be automatically circulated through the bypass. The pressure is reduced by the integrated multi-stage throttling and pressure reducing valve in the bypass.

Packing of Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 470 gallon liquid totes Special package is available on request. E FORUs’  is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition