HI-LO hydraulic pump: introducing Vivoil's new product

Introduction

Preannounced for some time now, the HI-LO Pump is the new arrival at Vivoil, enriching its range of hydraulic products.

The HI-LO Pump is useful when an operating cycle is required to run at different speeds, especially when a considerable part of the cycle is carried out with zero or far less than the actual working effort.

Typical applications for this type of pump are: forming machine tools, waste compactors, deep-drawing presses, log splitters, etc.

Like all Vivoil components, the HI-LO Pump is characterized by modularity, with different versions of front connections (shafts and flanges).

Operation

HI-LO stands for HIGH pressure / LOW flow and LOW pressure / HIGH flow.

A HI-LO Pump is essentially a double pump in which the drive pump is the pump providing the high pressure. The final pump provides the low pressure flow (added to the front pump) for fast movements.

The necessary valves have been integrated into the intermediate plate and cover:

• 3-way directional valve with external piloting.
• 2-way directional check valve (guide poppet type).

Below a given pressure (decoupling pressure, set by adjusting the set screw of the valve), the flow rate delivered by the pump is the sum of the flow rates of the front and rear stages.

Above the decoupling pressure, the rear stage is put into recirculation and delivers no flow. Under these conditions, only the front stage operates, whose flow rate is only given by its displacement, being able to reach the maximum pressure required by the application.

The function of the diverter valve is carried out by the directional valve in the pump cover, which automatically switches the flow direction depending on the piloting: when a certain pressure is exceeded, the valve switches and opens the recirculation channel of the pump. The non-return valve closes the connection between the two stages so that only the front stage reaches maximum pressure.

Main features

• 1 Inlet
• 1 Outlet
• 1 Directional spool-type valve
• 1 Directional control 2-way check valve
• 2 Pressure gauge sockets (Mb, Ma)

References

Explore the downloadable HI-LO Pump catalog, which includes all the necessary information about these components: technical data, diagrams, calculation formulas, configuration tables.

For further information or advice on selection, usage, and customization of the HI-LO Pump, feel free to contact us: our Sales and Technical Departments are at your disposal.