Air Driven Liquid Pumps

Air driven liquid pumps operate on the principle of differential working areas. An air piston drives a smaller diameter plunger or piston to provide a pressure ratio.The pressure ratio is the method of determining maximum outlet pressure available. HYDR-STAR model numbers reflect the nominal pressure ratio of the pumps.

HYDR-STAR liquid pumps will cycle automatically when compressed air is first applied to the drive. It will start cycling at its maximum speed thus producing maximum fluid flow. At this stage, the pump is acting as a transfer pump, filling the pressure system with fluid. As resistance increases in the system (creating back pressure to the pump), the pump will decrease its reciprocating action. Back pressure in the system finally balances with the incoming air drive pressure times the ratio. At this point, the pump will stall and maintain pressure without consuming any energy. If there is further demand on the system for flow, the pump will automatically start cycling again.

Air Driven Liquid Pumps

Air Driven Liquid Pumps


»Up to 100,000 psi (7000 bar) capability.
»Infinitely variable cycling speed.
»Stall feature at pre-determined pressure to hold that pressure without consuming power .
»Easily automated, with many modification and control options available.
»Suitable for most liquids and liquefied gases.
»Can be manufactured to meet CE, ATEX and NACE.
»Robust, reliable, compact and easy to maintain proven design.
»Unbalanced cycling spool provides immediate response to pressure changes.
»Also available in standard, Configuration required by customer.
»No need for air-line lubrication, which saves costs and prevents contamination.
»Air Drive line lubrication not required.
»Compatible with all hydraulic fluids, plain water, distilled & deionized water, solvents, mild chemicals and most liquefied aerosol type gases.
»Range of models to provide up to 100,000 psi intermittent output pressure.
»Alternative gases that can drive the pump include nitrogen,vapor from liquefied gas,pipeline natural gas and sour natural gas with proper modifications.
»Hydraulic pressure is held without energy consumption.
»Explosion proof ,requires no electrical power or connections.
»Intrinsically safe.
»Compact, lightweight and weatherproof.
»Easy to adapt automatic controls.
»Contamination tolerant.
»Ideal for stop-start applications under full load.
»Special design can be chosen, this design can replace the high pressure seal without disassembling the pump.

Easy handling

1. Initial operation 
The pump is prepared for operation manually:
»Connect supply lines (compressed air, suction and pressure lines).
»Set air drive pressure.
»Open compressed air supply slowly so that the high-pressure pump starts up .
2. Build up pressure
The pump technology executes all the steps for pressure build-up automatically: 
»Automatic cycling of 4/2-way valve (spoolcycling valve) by means of air pulses from the pilot valve (2/2-way valve)
»Suction of medium.
»Optimum cycling conditions thanks to large cross-sections .
3. Achieve and hold pressure
The pump controls the processes of reaching and holding pressure.
»Pump automatically stops operating when the operating pressure is reached due to equilibrium of forces
»Pressure is held.
»Pressure holding phase with no energy consumption or heat generation .
»Pump restarted automatically if operating pressure drops .


The pump model is selected according to the use requirements. Such as output pressure, output flow, medium and 
temperature, available air or gas drive pressure and flow. This guide will help you to pre-select the pump ideally suited 
for your application. If you have specific questions, Please contact us. We urge you to provide us with details of the 
duties you require from the pump, available air/gas drive pressure, and pressure/flow requirements, and we will 
recommend a model and any corresponding accessories.

The series and its functions

HYDR-STAR pumps offer the right solution for every application. They are suitable for different  or stepped flow rates as well as for different maximum allowable operating pressures.HYDR-STAR  pumps with two or three air drive sections reach the same final pressure as a HYDR-STAR  pump with one air drive section with 1/2 or 1/3 of the air drive. Double-acting pumps increase the pump capacity by around 50% in comparison to single-acting pumps and reduce the pulsation equally. 
The following model variants are available depending on the series:

»Pressure testing
»Jacking and Lifting.
»Valve actuator control
»Hydraulic cylinder actuation
»Roller tensioning
»Precision lubrication and spraying
»Work holding and power clamping
»Liquified gas transfer 
»Machine tools
»Well Control Panel