Gas driven pump for the dispensing and filtering of process fluid

• US 6,109,881 A
• Filed: 01/09/1998
• Issued: 08/29/2000
• Est. Priority Date: 01/09/1998
• Status: Expired due to Fees

• Current Assignee: Entegris Incorporated
• Original Assignee: Fastar Ltd.
• Inventors: Gibson, Gregory M., Snodgrass, Ocie T.
• Primary Examiner(s): Thorpe, Timothy S.
• Assistant Examiner(s): TORRENTE, DAVID JOHN
• Application Number:
  US09/005,172
• Time in Patent Office: 963 Days
• Field of Search: 417/384, 417/385, 417/387, 417/118, 417/120, 417/126, 417/137, 417/138, 417/143, 417/144
• US Class Current: 417/53
• CPC Class Codes: F04B 43/0081 systems, control, safety measures
• CPC Class Codes: F04B 43/067 the fluid being actuated directly by a piston

Abstract

A gas driven pump controls the process fluid pressure within a filtering and dispensing system. A pressure controller in the pump controls gas pressure within an enclosed chamber in the pump. The gas chamber is adjacent a floating piston that rests atop a layer of incompressible fluid in a fluid chamber. The incompressible fluid connects to a diaphragm head. As the gas pressure is increased, the floating piston will transmit that pressure through the incompressible fluid that then forces a relative displacement in the process fluid flow. A feedback system used in conjunction with the gas driven pump controls the gas pressure in order to regulate the process fluid flow.

In addition, a positive displacement compensator can be used in conjunction with the gas driven pump in order to further regulate the process flow.

Claims

1. A pump that utilizes gas and liquid mediums in separate chambers for dispensing process fluids comprising:

a housing;

a piston moveable within a portion of the housing to define first and second pump chambers, wherein the first pump chamber is designed to receive a substantially gas medium and the second pump chamber to receive a substantially fluid medium;

a working element within the second pump chamber, wherein when the second chamber is filled with the fluid medium, the fluid medium displaces the working element;

means for selectively varying pressure of the gas medium in the first chamber, wherein when the first chamber is filled with the gas medium, selective variation of the gas medium pressure providing selective displacement of the piston;

a pressure controller for controlling the gas pressure in the first pump chamber;

a position controller which determines the status of the piston and interacts with the pressure controller to control the position of the piston;

a means for gauging the displacement of the piston due to pressure changes in the first pump chamber;

a means for transmitting the displacement data to the position controller; and

a means controlled by the pressure controller for changing the pressure in the first pump chamber.

2. The pump of claim 1, wherein the means for gauging the displacement of the floating pump is a laser.

3. The pump of claim 1 wherein the means for gauging the displacement of the floating pump is a displacement sensor.

4. A method for accurately pumping process fluid, the method comprising the steps of:

disposing a first chamber containing gas and a second chamber containing intermediate fluid within a housing, wherein the gas in said first chamber has a pressure;

disposing a diaphragm in communication with said intermediate fluid within said housing and with said process fluid, wherein said diaphragm is within said second chamber;

disposing a piston in between said first chamber and said second chamber, wherein the piston is movable between said first chamber and said second chamber;

selectively varying the gas pressure in the first chamber, thereby varying the position of the piston, the intermediate fluid, and the diaphragm and enabling accurate pumping of said process fluid;

measuring the gas pressure;

measuring the displacement of the piston;

analyzing the relationship between gas pressure and piston displacement; and

adjusting the gas pressure to move the piston.