Good quality Stainless Steel Needle Valve - ZDT Model Automatic recirculation control valve – Convista

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ZDT series Automstic recirculation valve is a kind of pump protection device. It automatic protect centrifugal pump when pump body occur cavitation damage or unstable (especially conveying hot water at low load operation). Once pump flow is lower than the preseted flow, bypass can completely open to ensure the minimum required flow pump. Even running fully closed, namely main flow is zero, the minimum flow can also discharge from the bypass.

ZDT series has big bypass, and this valve is suitable for bypass with big flow, maximum pressure differential is 4MPa, specific choice is determined by factory.

Characteristics

• Simple structure, operation reliable and stable, with few movement parts.
• Be easy for installation, can be installed vertically or horizontally on pump outlet.
• Bypass flow is large, maximum flow is 60% of main flow, KV valve can be adjusted.
• Maximum bypass operating pressure differential is 4MPa. Bypass non-return function is optional.
• Applicable medium including: water, oil, methanol and other liquid medium.
• Working temperature: -196℃ to +130℃.

Diameter and pressure range

Valve body type: three-way casting valve

Nominal diameter: NPS1″-16″ (DN25, 32, 40, 50, 65, 80, 100, 200, 250, 300, 350, 400)

Nominal pressure: CL150#-400# (PN16, 25, 40, 64)

End connection type: Flange FF, RF, RTJ, BW, SW, etc.

Working principle

According to the difference of inductive main flow, main valve disc check cone of automatic recirculation valve will automatically move to a certain position. At the same time the main valve disc drive bypass valve stem, transfer the movement of main valve disc to bypass, through control bypass valve disc position, change bypass throttling area, so as to control bypass flow. When main valve disc back into valve seat closed, all flow backflow through bypass. When main valve disc to rise to top position, bypass is fully closed, all the flow of pump flow to process system. This valve set four functions in one body.

• Flow perception: Automatic recircution valve main valve disc can automatically perceive main flow of process system, thereby according to the flow to determine position of main valve disc and bypass disc.
• Recirculation control: Automatic recirculation valve can inhaled pump normal operation required minimum flow into storage device through bypass, so as to adjust pump H-Q charateristics, to realize recycling.
• Check valve: Automatic recirculation valve also has check valve effect, preventing the liquid backflow to pump body. Bypass non-return function is optional.
• Special bypass size can be customized. The max flow rate of bypass is subject to the max Kv value.

Major parts material