Positive displacement diaphragm pumps employing displacer valves

• US 4,583,920 A
• Filed: 12/28/1983
• Issued: 04/22/1986
• Est. Priority Date: 12/28/1983
• Status: Expired due to Fees

• Current Assignee: Atochem North America Inc (Arkema)
• Original Assignee: M&T Chemicals Incorporated (Arkema)
• Inventors: Lindner, Georg H.
• Primary Examiner(s): Husar, Cornelius J.
• Assistant Examiner(s): Cuomo, Peter M.
• Application Number:
  US06/566,363
• Time in Patent Office: 846 Days
• Field of Search: 417/244, 417/395, 417/510, 417/497, 417/254, 417/259, 417/264, 417/266, 417/317, 417/479
• US Class Current: 417/266
• CPC Class Codes: F04B 43/0733 with fluid-actuated pump inlet or outlet valves; with two or more pumping chambers in series

Abstract

A positive displacement pump utilizes at least three driven displacer valves and a plurality of driving membranes and at least one pumping membrane to withdraw minute quantities of corrosive fluid from a drum and discharge same from a spray nozzle. The pump is submerged within the fluid to be pumped and is driven by a remotely positioned pneumatic pulse generator comprising pneumatic logic circuitry. The driven displacer valves operate in a particular sequence to draw fluid into the pump body, advance same from pumping chamber to pumping chamber within the pump body, and then discharge same at a constant rate of discrete pulses through an outlet port. The pulse generator and logic circuitry provide the control pulses for operating the displacer valves at the proper times in the operational cycle. The delivery characteristics of the instant pump far exceed the performance capabilities of conventional pumps utilized for similar purposes.

Claims

1. A diaphragm pump for discharging minute quantities of liquid, said pump adapted to be submerged in a receptacle containing the liquid to be discharged, said pump comprising:

(a) a pump body composed of a plurality of segments,

(b) an inlet port defined at the lower end of the body and an outlet port defined thereabove,

(c) at least three spaced pumping chambers defined within said pump body between said inlet and outlet ports and in communication therewith,

(d) conduits interconnecting said pumping chambers in series between said inlet and outlet ports,

(e) at least one pumping diaphragm secured within said body between said segments to seal off one side of each pumping chamber,

(f) at least three driving diaphragms secured with said pump body, each in association with a respective one of said pumping chambers,

(g) at least three pressure chambers defined within said pump body, each in association with a respective one of said pumping chambers,

a pulse generator connected between a supply of pressurized air and said pump body to deliver control pulses of air to said pressure chambers in a particular sequence and for a desired duration of time, and

(i) at least three displacer valves secured to said pumping diaphragm and said driving diaphragms to draw fuid into said pump body through said inlet port, advance the fluid sequentially from pumping chamber to pumping chamber, and then discharge the fluid through said outlet port in discrete pulses, while preventing backflow through said pumping chambers, in response to said control pulses of air.

2. A diaphragm pump as defined in claim 1 wherein each driving diaphragm and said pumping diaphragm define an intermediate chamber therebetween, and means are provided for introducing a reference pressure into each intermediate chamber.

3. A diaphragm pump as defined in claim 1 wherein each displacer valve includes a cap with an aperture at one end and a button of chemically inert material that fits into said aperture.

4. A diaphragm pump as defined in claim 3 wherein the cap of each displacer valve further includes an enlarged annular shoulder, said shoulder guiding the movement of the displacer valve within each pumping chamber.

5. A diaphragm pump as defined in claim 3 wherein each displacer valve includes a spacer with a central bore extending therethrough, said spacer being secured between said driving diaphragm and said pumping diaphragm.

6. A diaphragm pump as defined in claim 1 wherein the pumping chambers are equal in volume.

7. A diaphragm pump as defined in claim 1 wherein there are three pumping diaphragms, each in association with a respective one of said pumping chambers.