Reciprocating pump and control using outlet valve position sensors

• US 4,915,591 A
• Filed: 05/09/1988
• Issued: 04/10/1990
• Est. Priority Date: 01/08/1986
• Status: Expired due to Fees

• Current Assignee: Saphirwerk Industrieprodukte AG (AG Ziegelwerke Horw-Gettnau-Muri Holding)
• Original Assignee: Saphirwerk Industrieprodukte AG (AG Ziegelwerke Horw-Gettnau-Muri Holding)
• Inventors: Funke, Herbert
• Primary Examiner(s): Smith, Leonard E.
• Assistant Examiner(s): Scheuermann, D. S.
• Application Number:
  US07/191,687
• Time in Patent Office: 701 Days
• Field of Search: 210/198.2, 417/63, 417/1, 417/18
• US Class Current: 417/18
• CPC Class Codes: F04B 13/00 Pumps specially modified to deliver fixed or variable measured quantities
• CPC Class Codes: F04B 53/007 Cylinder heads
• CPC Class Codes: F04B 53/1002 Ball valves
• CPC Class Codes: F04B 53/108 Valves characterised by the material
• CPC Class Codes: F04B 53/162 Adaptations of cylinders
• CPC Class Codes: F04B 53/166 Cylinder liners
• CPC Class Codes: F05C 2203/08 Ceramics; Oxides
• CPC Class Codes: F05C 2203/0873 Sapphire
• CPC Class Codes: F05C 2225/04 PTFE [PolyTetraFluorEthylene]
• CPC Class Codes: G01F 11/029 provided with electric controlling means G01F11/022 and G01F11/024 take precedence
• CPC Class Codes: G01N 2030/326 pumps
• CPC Class Codes: G01N 2030/328 valves, e.g. check valves of pumps

Abstract

The pump head liner of a small-size precision reciprocating metering pump, which has its application particularly in High Performance Liquid Chromatography (HPLC), is made of transparent material, preferably of synthetic sapphire or monocrystalline zirconium oxide. A pump head casing is designed such that a pump head liner is visually accessible. Cartridge-type check valve units of transparent components are associated with the pump head casing and pump head liner and mounted to be visually accessible. The opening and closing of a ball in a check valve unit can be monitored by an optical sensing system in order to obtain a feed-back signal for governing a control circuitry, having the purpose of compensating the influence of the specific compressibility of the liquid being pumped, upon the pumping efficiency of the displacement system under conditions of high and highest working pressures.

Claims

1. A precision reciprocating metering pump and control therefore comprising, a pump head casing with at least two displacement chambers having inlet and outlet ports, a piston for each displacement chamber, with at least one performing its displacement stroke at any given time whereby a pre-compression stroke is carried out prior to each such displacement stroke in order to compensate for the influence of the specific compressibility of the liquid being pumped on the pumping efficiency of the delivery system, a pair of check valve units associated with the inlet and outlet ports, at least one outlet check valve unit (28) comprising in part components made of transparent material, with a check valve ball (31) however, being colored or opaque, a piston position indicator and a sensor device monitoring the actual onset of the liquid displacement and connected to a piston speed control circuitry, whereby the underlying feed-back principle is characterized by said sensor device (111) monitoring the actual onset of the liquid displacement as triggered by the lifting of a check valve ball (31) from its seat (30) in at least one outlet check valve unit (28), and the sensor device (111) for monitoring the actual onset of liquid delivery, is an optical system, as for example, a light-gate, which is triggered by the lifting of the check valve ball (31) from its seat (30).

2. A precision reciprocating metering pump and control according to claim 1 characterized in that at least the housing of one outlet check valve unit (28) is made of sapphire or monocrystalline zirconium oxide and that the check valve ball (31) is of ruby.

3. A precision reciprocating metering pump and control therefore comprising, a pump head casing with at least two displacement chambers having inlet and outlet ports, a piston for each displacement chamber, with at least one performing its displacement stroke at any given time whereby a pre-compression stroke is carried out prior to each such displacement stroke in order to compensate for the influence of the specific compressibility of the liquid being pumped on the pumping efficiency of the delivery system, a pair of check valve units associated with the inlet and outlet ports, the check valve units having a ball engageable with a seat, a piston position indicator and a sensor device monitoring the actual onset of the liquid displacement and connected to a piston speed control circuitry, whereby the underlying feed-back principle is characterized by said sensor device monitoring the actual onset of the liquid displacement is triggered by the lifting of a check valve ball (31a) from its seat in at least one outlet check valve unit (28), and the check valve ball of at least one outlet check valve unit being made of ferro-magnetic material, preferably of stainless steel, and, the sensor device monitoring the actual onset of the liquid displacement senses magnetically the opening movement of the check valve ball.

4. A precision reciprocating metering pump and control according to claim 3 characterized in that the check valve ball of ferro-magnetic material is coated with a ceramic material, such as for example titanium carbide.