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Explain how an LC pump is able to deliver a relatively constant pressure with a piston...

Explain how an LC pump is able to deliver a relatively constant pressure with a piston pump.

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Expert Solution

  • LC pumping systems are needed to deliver specific amounts of mobile phase at a constant flow rate. Constant pressure can be provided by passing the pressurized solvent through a pulse-dampening device. Tubing and connections should be able of withstanding the pressures developed by the pumping system. Many HPLC pumps are having a facility for "bleeding" the system of entrapped air bubbles.

Two types of constant pressure pumps:

1. Reciprocating piston pump 2. Positive displacement pumps

Reciprocating piston pump can maintain the flow for a long time while the Positive displacement pumps have to be refilled after whole syringe volume displaces. For piston pump, the rate is adjusted by controlling the distance piston retracts which limits the amount of liquid pushed out in each stroke it can also be done through cam rotating speed.

Dual piston pumps can be used to more efficiently provide constant pressure as it uses dual headed reciprocating pumps.Both the pumps are driven by a common eccentric cam. This common drive allows one piston to pump while other to refill. Due to the overlap of flow- profiles there is a decrease in the pulsation of the pump.

queen_honey_blossom answered 2 years ago
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