Diaphragm pump

• US 6,126,403 A
• Filed: 12/22/1997
• Issued: 10/03/2000
• Est. Priority Date: 09/18/1997
• Status: Expired due to Term

• Current Assignee: Patent Counsel TRW Inc., Yamada TS Company Limited
• Original Assignee: Yamada TS Company Limited
• Inventors: Yamada, Kazumasa
• Primary Examiner(s): Freay, Charles G.
• Assistant Examiner(s): TORRENTE, DAVID JOHN
• Application Number:
  US08/995,830
• Time in Patent Office: 1,016 Days
• Field of Search: 417/46, 417/392, 417/395, 91/274
• US Class Current: 417/46
• CPC Class Codes: F04B 2201/0201 Position of the piston
• CPC Class Codes: F04B 2203/10 of linear elastic fluid motors
• CPC Class Codes: F04B 43/0081 systems, control, safety measures
• CPC Class Codes: F04B 43/0736 with two or more pumping chambers in parallel

Abstract

A diaphragm pump is provided with a diaphragm defining a pump chamber and a drive chamber in the pump housing, a driving fluid is supplied to the drive chamber and a pump fluid is expelled from the pump chamber. The diaphragm pump is provided with pressure control means which, when the pressure in the pump chamber surpasses the pressure in the drive chamber neighboring the pump chamber across the diaphragm, controls the pressure of the driving fluid based upon output signals from pressure sensors in such a manner that the pressure in the fluid chamber will become higher than the pressure in the neighboring drive chamber. This makes it possible to prevent a diaphragm reversal phenomenon, wherein a diaphragm that should expand toward the pump chamber contracts toward the drive chamber instead during reciprocation of the diaphragm.

Claims

1. A diaphragm pump for discharging a pump fluid continuously by a diaphragm defining a pump chamber and a drive chamber, comprising:

pressure control means for controlling pressure of a driving fluid, which is supplied to said drive chamber neighboring said pump chamber via the intermediary of said diaphragm, in such a manner that pressure in said drive chamber becomes higher than pressure in said pump chamber when the pressure in said pump chamber is equal to or greater than the pressure in said drive chamber, whereby reversal of said diaphragm is prevented independently of the pressure in said pump chamber, wherein said pressure control means includes a pressure sensor for sensing the pressure in said pump chamber.

2. A diaphragm pump for discharging a pump fluid continuously by a diaphragm defining a pump chamber and a drive chamber, comprising:

pressure control means for controlling pressure of a driving fluid, which is supplied to said drive chamber neighboring said pump chamber via the intermediary of said diaphragm, in such a manner that pressure in said drive chamber becomes higher than pressure in said pump chamber when the pressure in said pump chamber is equal to or greater than the pressure in said drive chamber, whereby reversal of said diaphragm is prevented independently of the pressure in said pump chamber, wherein said pressure control means includes pressure sensors for sensing the pressure in said drive chamber and the pressure in said pump chamber.

3. A diaphragm pump, which has a pair of diaphragms each of which defines a pump chamber and a drive chamber, for discharging a pump fluid continuously by reciprocation of the pair of diaphragms, comprising:

pressure control means for controlling pressure of a driving fluid, which is supplied to said drive chambers neighboring said pump chambers via the intermediary of the respective diaphragms, in such a manner that pressure in said drive chambers becomes higher than pressure in said pump chambers when the pressure in said pump chambers is equal to or greater than the pressure in said drive chambers, whereby reversal of each diaphragm is prevented, wherein said pressure control means includes pressure sensors for sensing the pressure in respective pump chambers.

4. A diaphragm pump, which has a pair of diaphragms each of which defines a pump chamber and a drive chamber, for discharging a pump fluid continuously by reciprocation of the pair of diaphragms, comprising:

pressure control means for controlling pressure of a driving fluid, which is supplied to said drive chambers neighboring said pump chambers via the intermediary of the respective diaphragms, in such a manner that pressure in said drive chambers becomes higher than pressure in said pump chambers when the pressure in said pump chambers is equal to or greater than the pressure in said drive chambers whereby, reversal of each diaphragm is prevented, wherein said pressure control means includes pressure sensors for sensing the pressure in respective drive chambers and the pressure in each of respective pump chambers.

5. A diaphragm pump including a connecting body having two ends each of which is provided with a diaphragm defining a pump chamber and a drive chamber, and a control circuit for controlling reciprocation timing of said connecting body as well as timing at which supply of a driving fluid to each of said drive chambers is changed over, wherein when said connecting body is driven toward a first side thereof, the driving fluid is supplied to the drive chamber located on the first side of said connecting body, pump fluid is expelled from the pump chamber located on the first side and pump fluid is drawn into the pump chamber located on a second side of said connecting body while driving fluid is discharged from the drive chamber located on the second side, and when said connecting body is driven toward the second side thereof, the driving fluid is supplied to said drive chamber located on the second side of said connecting body, pump fluid is expelled from said pump chamber located on the second side and pump fluid is drawn into said pump chamber located on the first side of said connecting body while driving fluid is discharged from said drive chamber located on the second side, whereby the pump fluid is discharged continuously by reciprocation of said connecting body, the diaphragm pump comprising:

a pressure sensor provided in each pump chamber for sensing pressure of the pump fluid in each pump chamber;

a pressure sensor provided in each drive chamber for sensing pressure of the driving fluid in each drive chamber; and

pressure control means for controlling the pressure of the driving fluid based upon output signals from both of said pressure sensors in such a manner that the pressure of the driving fluid in each drive chamber neighboring each pump chamber becomes higher than the pressure of the pump fluid in the pump chamber when the pressure of the pump fluid in the pump chambers is equal to or greater than the pressure of the driving fluid in the drive chambers neighboring the pump chambers via the intermediary of the respective diaphragms.

6. The diaphragm pump according to claim 5, wherein passageways for supplying the driving fluid are connected to respective ones of said drive chambers and said pressure control means is provided in each passageway at a point along the length thereof.