A permanent pressure gauge adaptor for use with bladder accumulators offers users a clear indication of gas pre-charge pressure without the need to connect up a supplementary gauge.
Parker Hannifin's Cylinder Division has launched a new permanent pressure gauge adaptor for use with BAE series bladder accumulators. In combination with any one of a number of pressure gauges, it offers users a clear indication of gas pre-charge pressure without the need to connect up a supplementary gauge. Designed specifically for use with bladder accumulators, the GAE Permanent Pressure Gauge Adaptor will see use in a number of industrial applications; Parker is also keen to point out its use in concrete pumping - an unusual, mobile sector application for this technology.

According to Andrew Delaney, from Parker's Cylinder Division: 'This application is a graphic illustration of a bladder accumulator's performance capabilities as well as its tolerance to contamination.

The new adaptor enables optimum system performance to be maintained, while its steel construction offers a long, reliable service life.

With chromated surfaces, corrosion is not an issue.' The relationship between pre-charge pressure and system pressure is critical if hydraulic applications are to maintain optimum efficiency.

Hydro-pneumatic accumulators provide a means of regulating performance by using the differing mechanical properties of liquids and gases.

As gases are compressible while liquids are not, gas compressed by fluid at system pressure enables energy to be stored and released when a predetermined pressure level is met.

This stored energy can be used to supplement pump pressure and allows smaller system components to be used.

Accumulators are also useful as a source of energy in emergencies and for damping pulsating flows due to pump action.

The adaptor simply mounts onto the gas valve of the bladder allowing clear and unhindered access to both the pressure gauge and, space permitting, the gas valve on its side.

When adjustment is required, it can also be used in conjunction with a UCA Charging and Gauging Assembly, which offers the benefit of quick and easy charging and monitoring of pre-charge pressure.

Maximum working pressure for the adaptor is 330 bar and its working temperature range is between -15 and 80degC.

Connection to the bladder/accumulator is via a 7/8 - 14UNF port, the pressure gauge is attached using a G1/2 port and the gas valve port on the side is 1/2 - 20UNF - all common port sizes ensuring maximum compatibility.

Accumulators come in many guises; all performing similar functions.

These include acting as a supplementary source of energy when system pressure falls below pre-charge pressure, damping out any pump oscillations, improving system efficiency, supplementing pump delivery, compensating for thermal stresses in the system and absorbing hydraulic shocks.

They are pre-charged with an inert gas such as nitrogen, which is first compressed through pre-charging and then by the application of system pressure to the hydraulic fluid.

In this compressed state, the nitrogen acts as a gaseous 'spring' storing energy which is released when system pressure falls below the pre-charge level.

Precharge pressures can be set by the manufacturer or by the customer using a charging and gauging kit.

These kits can also be used when the adaptor is in use to perform supplemental checking and adjustment of pre-charge pressure.