Serial type pump comprising a heat exchanger

Patent metadata

Field	Value
Publication number	US-9803627-B2
Application number	US-76380610-A
Country	US
Kind code	B2
Filing date	Apr 20, 2010
Priority date	Apr 20, 2009
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A pump unit comprises a primary piston pump, a secondary piston pump, and a flow path adapted for fluidically connecting in series the primary piston pump and the secondary piston pump. The pump unit's duty cycle comprises a delivery-and-fill phase, in which the primary piston pump supplies a flow of liquid to the secondary piston pump, and during the delivery-and-fill phase, the flow of liquid supplied by the primary piston pump is partly used for filling up the secondary piston pump and partly used for maintaining another flow of liquid dispensed across the secondary piston pump. The flow path comprises a heat exchanger, wherein liquid supplied by the primary piston pump passes through the heat exchanger before being supplied to the secondary piston pump. The heat exchanger is adapted for reducing a temperature difference between a temperature of liquid supplied to heat exchanger and a temperature of the secondary piston pump, in that the heat exchanger is kept at a temperature of the secondary piston pump, so that after having passed the heat exchanger, liquid supplied to the secondary piston pump has substantially the same temperature as the secondary piston pump itself.

First claim

The invention claimed is:

1. A pump unit comprising:
a primary piston pump,
a secondary piston pump,
a flow path fluidically connecting in series the primary piston pump and the secondary piston pump, wherein:
the pump unit is configured for executing a duty cycle comprising a delivery-and-fill phase, in which the primary piston pump supplies a flow of liquid to the secondary piston pump, and during the delivery-and-fill phase, the flow of liquid supplied by the primary piston pump is partly used for filling up the secondary piston pump and partly used for maintaining continuous flow of liquid dispensed at an outlet of the secondary piston pump,
the flow path comprises a heat exchanger, wherein liquid supplied by the primary piston pump passes through the heat exchanger before being supplied to the secondary piston pump, and
the heat exchanger is configured for reducing a temperature difference between a temperature of liquid supplied to the heat exchanger and a temperature of the secondary piston pump influenced by flow rates of liquid supplied by the primary piston pump, and enforced by the heat exchanger, during the delivery-and-fill phase, in that the heat exchanger is kept at a temperature of the secondary piston pump, so that after having passed the heat exchanger, liquid supplied to the secondary piston pump during the delivery-and-fill phase has substantially the same temperature as the temperature of the secondary piston pump,
and further comprising one or more of the following:
a thermostatic heating element configured to keep both the heat exchanger and the secondary piston pump at a predefined temperature;
the heat exchanger comprises a heat reservoir and one or more capillaries in thermal contact with the heat reservoir;
a control unit configured to superpose at least one corrective movement to at least one of the primary piston pump and secondary piston pump so as to compensate for volumetric effects that are due to temperature variations of the liquid;
a common heat reservoir thermally coupling the heat exchanger and the secondary piston pump;
the pump unit being configured to execute the duty cycle such that the delivery-and-fill phase extends over less than 10% of the duty cycle; or
the heat exchanger comprising a pattern of heat exchange elements configured to intensify the thermal contact of liquid to the heat exchanger.

2. The pump unit of claim 1 , wherein the heat exchanger is adapted for at least one of:
substantially bringing the liquid supplied by the primary piston pump to a predefined temperature before said liquid is supplied to the secondary piston pump;
substantially bringing the liquid supplied by the primary piston pump to the secondary piston pump's temperature.

3. A liquid separation system for separating compounds of a sample liquid in a mobile phase, the liquid separation system comprising:
a mobile phase drive adapted to drive the mobile phase through the liquid separation system, said mobile phase drive comprising a pump unit according to claim 1 , and a separation unit adapted for separating compounds of the sample liquid in the mobile phase.

4. The liquid separation system of claim 3 , further comprising at least one of:
a sample injector adapted to introduce the sample liquid into the mobile phase;
a detector adapted to detect separated compounds of the sample liquid;
a collection unit adapted to collect separated compounds of the sample liquid;
a data processing unit adapted to process data received from the liquid separation system;
a degassing apparatus for degassing the mobile phase.

5. The pump unit of claim 1 , wherein the heat exchanger is thermally coupled to the secondary piston pump.

6. The pump unit of claim 1 , wherein the heat exchanger is mounted onto the secondary piston pump.

7. The pump unit of claim 1 , wherein the duty cycle comprises an intake phase executed by the primary piston pump, followed by a compression jump executed by the primary piston pump, followed by the delivery-and-fill phase, and wherein the compression jump and the delivery-and-fill phase cause temperature variations in the fluid supplied by the primary piston pump.

8. The pump unit of claim 7 , wherein the duty cycle comprises a dispensing phase executed by the secondary piston pump during the intake phase executed by the primary piston pump, followed by an intake phase executed by the secondary piston pump during the delivery-and-fill phase.

Assignees

• Witt Klaus
• Shoykhet Konstantin
• Herzog Philip
• Agilent Technologies Inc

Inventors

• Witt Klaus
• Shoykhet Konstantin
• Herzog Philip

Classifications

• G01N30/24

  Automatic injection systems · CPC title

• F04B2205/10

  Inlet temperature · CPC title

• F04B2205/112

  between two stages in a multi-stage pump · CPC title

• F04B23/06 Primary

  the pumps being all of reciprocating positive-displacement type · CPC title

• G01N30/30

  of temperature · CPC title