When an Integra Bladder Pump is lowered into a well the hydraulic pressure of the water allows formation water to enter the central Teflon chamber (the bladder) through the inlet filter.

When gas or air pressure is applied to the drive line it circulates into the space around the bladder, causing it to collapse, and pushing the water up into the sample line.

Check valves ensure that no water flows back down into the pump or the formation.

When the gas/air pressure is vented (released) more formation water enters the bladder. When the pressure is reapplied, once again the fresh formation water is pushed up towards the surface.

The pressure/vent cycles are repeated, providing a steady flow of water up the sample line, without any stripping of volatile gases from the sample. Turbidity is minimized due to the low flow rate and gentle pumping action.

Thus a high quality VOC groundwater sample is obtained.

When large purge volumes are required, Solinst Integra Bladder Pumps can deliver higher flow rates than the 100 ml/min. recommended for low flow purge and sample methods.

Alternatively a simple conversion kit can be used to quickly turn an Integra Bladder Pump into a Solinst Double Valve Pump (DVP). These pneumatic drive DVPs have higher flow rates than bladder pumps.

Flow rates vary with depth of pump below surface, depth below water level, size of drive and sample tubing, drive and vent cycle times, gas pressure applied, aquifer recharge, and size of pump body.

Flow rates of the Integra Bladder Pump and the DVP compare favourably with published data for similar types and sizes of pumps, under similar conditions, for example:

1.66" x 2' (42 mm x 610 mm) Bladder Pump at 100 psi, with 1/4" OD drive line and 3/8" OD sample line; 50' (15 m) below grade with 25’ (7.5m) below water level gives 1.5 litres/min.