Duplex Metering Pump Having a Single Liquid End

Abstract

An improved motor driven duplex metering pump comprising two diaphragms in a single duplex liquid end pump housing assembly. The single duplex liquid end is rigidly attached to a main pump housing at a single mounting position and includes integrated check valves to allow for a single discharge process connection and a single suction process connection. The pump utilizes an improved cam mechanism that creates continuous positive uniform reciprocating motion. That continuous positive uniform reciprocating motion is imparted from its cam mechanism and its follower assembly to drive shafts that are connected to a cross arm and in collectively they impart the same motion to its two diaphragms that reciprocate 180° out of phase from each other. The result is substantially continuous liquid flow rate delivery by the invention.

What is claimed is: 
     
         1 . A liquid end of a duplex pump, the liquid end comprising:
 a body having opposite first and second sides, a first pump cavity formed through said first side, a second pump cavity formed through said second side, a first suction passage formed through said body and in fluidic communication with said first pump cavity, a first discharge passage formed through said body and in fluidic communication with said first pump cavity, a second suction passage formed through said body and in fluidic communication with said second pump cavity, a second discharge passage formed through said body and in fluidic communication with said second pump cavity, a suction port formed through said body and in fluidic communication with said first and second suction passages, and a discharge port formed through said body and in fluidic communication with said first and second discharge passages.   
     
     
         2 . The liquid end of  claim 1 , further comprising:
 a first check valve disposed across said first suction passage;   a second check valve disposed across said first discharge passage;   a third check valve disposed across said second suction passage;   a fourth check valve disposed across said second discharge passage;   wherein said first and second check valves operate cooperatively to alternate a fluid flow in a first direction from said suction port through said first suction passage and a second direction from said suction port through said second suction passage; and   wherein said second and forth check valves operate cooperatively to alternate a fluid flow in a third direction from said first discharge passage through said discharge port and a fourth direction from said second discharge passage through said discharge port.   
     
     
         3 . The liquid end of  claim 2 , wherein each of said first, second, third, and fourth check valves are disposed within said body. 
     
     
         4 . The liquid end of  claim 1 , further comprising:
 a first diaphragm disposed across said first pump cavity;   a first cap attached to said first side and closing said first pump cavity;   a second diaphragm disposed across said second pump cavity; and   a second cap attached to said second side and closing said second pump cavity.   
     
     
         5 . The liquid end of  claim 4 , further comprising:
 first and second connecting shaft passages formed through said body between said first and second sides;   a first connecting shaft disposed within said first connecting shaft passage for reciprocating motion therein;   a second connecting shaft disposed within said second connecting shaft passage for reciprocating motion therein;   a first cross arm attached to and extending between first ends of said first and second connecting shafts;   a second cross arm attached to and extending between second ends of said first and second connecting shafts;   a first diaphragm shaft connected at one end to said first cross arm for conjoined movement therewith and connected at a second end to said first diaphragm; and   a second diaphragm shaft connected at one end to said second cross arm for conjoined movement therewith and connected at a second end to said second diaphragm.   
     
     
         6 . The liquid end of  claim 5 , wherein:
 said first diaphragm shaft extends through said first cap and is fluidically sealed therewith; and   said second diaphragm shaft extends through said second cap and is fluidically sealed therewith.   
     
     
         7 . The liquid end of  claim 1 , further comprising:
 a first check valve disposed across said first suction passage;   a second check valve disposed across said first discharge passage;   a third check valve disposed across said second suction passage;   a fourth check valve disposed across said second discharge passage;   wherein said first and second check valves operate cooperatively to alternate a fluid flow in a first direction from said suction port through said first suction passage and a second direction from said suction port through said second suction passage;   wherein said second and forth check valves operate cooperatively to alternate a fluid flow in a third direction from said first discharge passage through said discharge port and a fourth direction from said second discharge passage through said discharge port;   a first diaphragm disposed across said first pump cavity;   a first cap attached to said first side and closing said first pump cavity;   a second diaphragm disposed across said second pump cavity;   a second cap attached to said second side and closing said second pump cavity;   first and second connecting shaft passages formed through said body between said first and second sides;   a first connecting shaft disposed within said first connecting shaft passage for reciprocating motion therein;   a second connecting shaft disposed within said second connecting shaft passage for reciprocating motion therein;   a first cross arm attached to and extending between first ends of said first and second connecting shafts;   a second cross arm attached to and extending between second ends of said first and second connecting shafts;   a first diaphragm shaft connected at one end to said first cross arm for conjoined movement therewith and connected at a second end to said first diaphragm; and   a second diaphragm shaft connected at one end to said second cross arm for conjoined movement therewith and connected at a second end to said second diaphragm.   
     
     
         8 . The liquid end of  claim 7 , wherein each of said first, second, third, and fourth check valves are disposed within said body. 
     
     
         9 . The liquid end of  claim 7 , wherein:
 said first diaphragm shaft extends through said first cap and is fluidically sealed therewith; and   said second diaphragm shaft extends through said second cap and is fluidically sealed therewith.   
     
     
         10 . A duplex pump comprising:
 a liquid end having a body, a suction port and a discharge port through said body, a first diaphragm disposed within a first pump cavity formed into said body, a second diaphragm disposed within a second pump cavity formed into said body, said first and second pump cavities being fluidically connected to said suction port and said discharge port;   a transmission operatively connected to said first and second diaphragms to reciprocate said first and second diaphragms; and   a motor operatively connected to said transmission and operating to drive said transmission.   
     
     
         11 . The duplex pump of  claim 10 , wherein said liquid end further comprises:
 first and second connecting shaft passages formed through said body between said first and second sides;   a first connecting shaft disposed within said first connecting shaft passage for reciprocating motion therein;   a second connecting shaft disposed within said second connecting shaft passage for reciprocating motion therein;   a first cross arm attached to and extending between first ends of said first and second connecting shafts;   a second cross arm attached to and extending between second ends of said first and second connecting shafts;   a first diaphragm shaft connected at one end to said first cross arm for conjoined movement therewith and connected at a second end to said first diaphragm;   a second diaphragm shaft connected at one end to said second cross arm for conjoined movement therewith and connected at a second end to said second diaphragm; and   wherein said transmission is operatively connected to said first and second diaphragms by said first and second connecting shafts.   
     
     
         12 . The duplex pump of  claim 10 , wherein said liquid end further comprises:
 a first suction passage formed through said body and in fluidic communication with said first pump cavity, a first discharge passage formed through said body and in fluidic communication with said first pump cavity, a second suction passage formed through said body and in fluidic communication with said second pump cavity, a second discharge passage formed through said body and in fluidic communication with said second pump cavity;   wherein said suction port is in fluidic communication with said first and second suction passages; and   wherein said discharge port is in fluidic communication with said first and second discharge passages.   
     
     
         13 . The duplex pump of  claim 12 , wherein said liquid end further comprises:
 a first check valve disposed across said first suction passage;   a second check valve disposed across said first discharge passage;   a third check valve disposed across said second suction passage;   a fourth check valve disposed across said second discharge passage;   wherein said first and second check valves operate cooperatively to alternate a fluid flow in a first direction from said suction port through said first suction passage and a second direction from said suction port through said second suction passage; and   wherein said second and forth check valves operate cooperatively to alternate a fluid flow in a third direction from said first discharge passage through said discharge port and a fourth direction from said second discharge passage through said discharge port.   
     
     
         14 . The duplex pump of  claim 10 , wherein said motor is a stepper motor. 
     
     
         15 . A duplex pump comprising:
 a liquid end having a body, a suction port and a discharge port through said body, a first diaphragm disposed within a first pump cavity formed into said body, a second diaphragm disposed within a second pump cavity formed into said body, said first and second pump cavities being fluidically connected to said suction port and said discharge port;   a first transmission operatively connected to said first and second diaphragms to reciprocate said first and second diaphragms; and   a first motor operatively connected to said first transmission and operating to drive said first transmission;   a second transmission operatively connected to said first and second diaphragms to reciprocate said first and second diaphragms; and   a second motor operatively connected to second transmission and operating to drive said second transmission.   
     
     
         16 . The duplex pump of  claim 15 , wherein each of said first and second motors are stepper motors. 
     
     
         17 . The duplex pump of  claim 15 , wherein said liquid end further comprises:
 first and second connecting shaft passages formed through said body between said first and second sides;   a first connecting shaft disposed within said first connecting shaft passage for reciprocating motion therein;   a second connecting shaft disposed within said second connecting shaft passage for reciprocating motion therein;   a first cross arm attached to and extending between first ends of said first and second connecting shafts;   a second cross arm attached to and extending between second ends of said first and second connecting shafts;   a first diaphragm shaft connected at one end to said first cross arm for conjoined movement therewith and connected at a second end to said first diaphragm;   a second diaphragm shaft connected at one end to said second cross arm for conjoined movement therewith and connected at a second end to said second diaphragm;   wherein said first transmission is operatively connected to said first and second diaphragms by said first and second connecting shafts; and   wherein said second transmission is operatively connected to said first and second diaphragms by said first and second connecting shafts.   
     
     
         18 . The duplex pump of  claim 15 , wherein said liquid end further comprises:
 a first suction passage formed through said body and in fluidic communication with said first pump cavity, a first discharge passage formed through said body and in fluidic communication with said first pump cavity, a second suction passage formed through said body and in fluidic communication with said second pump cavity, a second discharge passage formed through said body and in fluidic communication with said second pump cavity;   wherein said suction port is in fluidic communication with said first and second suction passages; and   wherein said discharge port is in fluidic communication with said first and second discharge passages.   
     
     
         19 . The duplex pump of  claim 18 , wherein said liquid end further comprises:
 a first check valve disposed across said first suction passage;   a second check valve disposed across said first discharge passage;   a third check valve disposed across said second suction passage;   a fourth check valve disposed across said second discharge passage;   wherein said first and second check valves operate cooperatively to alternate a fluid flow in a first direction from said suction port through said first suction passage and a second direction from said suction port through said second suction passage; and   wherein said second and forth check valves operate cooperatively to alternate a fluid flow in a third direction from said first discharge passage through said discharge port and a fourth direction from said second discharge passage through said discharge port.   
     
     
         20 . The duplex pump of  claim 19 , wherein each of said first, second, third, and fourth check valves are disposed within said body.