Variable Pitch and Hub Helical Inducer

Improves NPSHr performance.

One of the most common application areas for inducers is liquefied natural gas (LNG) in-tank pump applications where net positive suction head (NPSH) determines the non-useable height of the liquid inside a storage tank. Storage tanks cannot be pressurized due to their size and construction, which limits the available suction pressure to the pump.
It is possible to delay cavitation and enhance suction power of a new or existing cryogenic pump via inducer technology where suction pressure is less than ideal. Cryodynamics® variable pitch and hub helical inducers achieve a suction specific speed, ranging from 55,000 to 75,000 US units, while maintaining high flow-out capabilities.

Typical Cryodynamics pump hydraulic components consist of an inducer, an impeller, and a diffuser vane. Each variable pitch and hub inducer is custom designed by considering the impeller eye (inlet) geometry to achieve maximum cavitation performance, and gets a matching impeller to meet the application requirements. A Cryodynamics variable pitch and hub inducer further increases head via a change in blade angle from suction to discharge. With an increase in blade angle at discharge, the inducer produces more head with an increase in absolute velocity. More importantly, with the variation in blade angle from suction to discharge, shockless entry at the design flow can be obtained. A change in hub diameter from suction to discharge allows for more drastic changes in blade angle, and hence higher pressure output.

variable pitch helical inducer diagram

Technical Specifications:

inducer technical specifications (constant pitch vs variable pitch)