Pneumatic skimmer pumps

The bladder pump is similar in concept, with a flexible membrane bladder attached to the air line inside the chamber. A bladder prevents operating air from contacting pumped fluids therefore, when air is released to the atmosphere it does not contain vapors. 

Suspended pneumatic skimmers recover LNAPL where sufficient product is accumulated to allow timed recovery. They are installed as single-pump recovery units and also as an NAPL recovery pump for two-pump recovery units. After the cycle time is adjusted for a semi-steady-state pumping situation, they are easily controlled. 

Raising and lowering the intake to accommodate fluctuating fluid levels or adjusting the time cycle as LNAPL accumulates are the primary adjustments necessary. 

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Fig. 11.5. Diagram illustrating the components of an ESI source. A solution from a pump or the eluent from an HPLC is introduced through a narrow gage needle (approximately 150 pm i.d.). The voltage differential (4-5 kV) between the needle and the counter electrode causes the solution to form a fine spray of small charged droplets. At elevated flow rates (greater than a few pl/min up to 1 ml/min), the formation of droplets is assisted by a high velocity flow of N2 (pneumatically assisted ESI). Once formed, the droplets diminish in size due to evaporative processes and droplet fission resulting from coulombic repulsion (the so-called coulombic explosions ). The preformed ions in the droplets remain after complete evaporation of the solvent or are ejected from the droplet surface (ion evaporation) by the same forces of coulombic repulsion that cause droplet fission. The ions are transformed into the vacuum envelope of the instrument and to the mass analyzer(s) through the heated transfer tube, one or more skimmers and a series of lenses.

For the above estimate, total equipment costs for the SFC system was estimated at 35,540. This included the vertical fin coalescing unit, oleophilic ceramic granules, pumps, a pneumatic control system, and such ancillary equipment as a 2000-gal bulk tank with fittings, a skimmer, necessary switches, valves, piping, and wires (D11018P, p. 28). 

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