Apparatus for injecting measured quantities of liquid into a fluid stream

• US 4,558,715 A
• Filed: 05/16/1984
• Issued: 12/17/1985
• Est. Priority Date: 05/16/1984
• Status: Expired due to Term

• Current Assignee: Dosmatic USA Incorporated (Dover Corporation), Kowatachi International Limited
• Original Assignee: Kowatachi International Limited
• Inventors: Perrinet, Paul M., Walton, Frank A.
• Primary Examiner(s): Cohan, Alan
• Assistant Examiner(s): Hepperle, Stephen M.
• Application Number:
  US06/610,755
• Time in Patent Office: 580 Days
• Field of Search: 137/99, 417/399, 417/403, 417/511, 91/224, 91/228, 91/229, 91/347, 251/75, 251/76, 92/13.41, 92/13.5
• US Class Current: 137/99
• CPC Class Codes: G05D 11/035 with auxiliary non-electric power
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: Y10T 137/2516 Interconnected flow displacement elements

Abstract

A liquid additive injection pump has a hydraulic motor comprising a differential piston assembly reciprocable in a housing under the urging of a primary liquid into which an additive is to be injected. The piston assembly carries valves which are responsive to movement of the piston assembly to open and close to effect the transfer of a primary fluid charge from the pump motor to a discharge passage and to effect reciprocation of the piston assembly. The motor piston is connected to a central axially disposed longitudinally extending piston rod which extends into an additive injection pump cylinder and engages a floating additive injection pump piston having a stack of additive pump displacement control washers engaged therewith and disposed on the piston rod. A spring biased toggle type linkage snaps the motor valves into open and closed positions to provide positive movement of the valve members. Liquid additive is injected into the primary fluid stream at the outlet passage of the apparatus and downstream of the motor mechanism to prevent exposure of the pump actuating motor to the additive substance.

Claims

1. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores of different diameters, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means for displacing a quantity of additive fluid from said additive fluid cylinder means for injection into said primary fluid;

piston rod means interconnecting said piston assembly with said additive fluid piston means for reciprocation with said piston assembly;

first and second valves associated with said piston assembly and movable to respective positions to place said first and second chambers in communication with each other and close off communication between said second and third chambers and alternately close off said first chamber from said second chamber while communiating said second chamber with said third chamber;

a shaft disposed on said piston assembly for moving said valves between said positions;

first toggle means for urging said shaft into respective ones of said positions in response to movement of said shaft for biasing said valves in said positions, respectively; and

second toggle means connected to said first valve for urging said first valve in open and closed positions, respectively;

said piston assembly, said additive fluid piston means and said shaft being arranged generally coaxial with a central axis of said piston rod means for causing forces acting on said piston assembly to reciprocate said additive fluid piston means to be directed substantially along said axis, and said shaft including means coaxial with a central axis of said piston rod means at opposite ends of said shaft engageable with said housing to initiate movement of said shaft in opposite directions in response to movement of said shaft with said piston assembly toward opposed limit positions of said piston assembly.

2. The apparatus set forth in claim 1 wherein:

said first valve means comprises a first closure member slidably mounted on said shaft and movable between open and closed positions relative to said piston assembly to provide for conducting primary fluid from said first chamber to said second chamber.

3. The apparatus set forth in claim 2 wherein said second toggle means comprises:

leaf spring means interconnected between said first closure member and said piston assembly and operable to bias said first closure member in said open and closed positions, respectively.

4. The apparatus set forth in claim 1 wherein:

said shaft includes a bifurcated extension part forming opposed coextensive arms disposed on opposite sides of said piston rod means and having distal ends engageable with means on said housing to limit movement of said shaft in one direction of movement of said piston assembly.

5. The apparatus set forth in claim 1 wherein:

said additive fluid piston means divides said additive fluid cylinder means into first and second additive fluid chambers, said additive fluid piston means is slidably mounted on said piston rod means and includes passage means interconnecting said additive fluid chambers in at least one position of said additive fluid piston means, and said piston rod means includes spaced apart stop means formed thereon for reciprocating said additive fluid piston means through an additive fluid intake and delivery stroke to effect displacement of a predetermined charge of additive fluid into said primary fluid during a reciprocating stroke cycle of said piston assembly.

6. The apparatus set forth in claim 5 including:

means forming an additive fluid injection passage in said housing and in communication with said additive fluid cylinder means and said discharge passage for injecting additive fluid into said primary fluid downstream of said first chamber in the direction of flow of primary fluid through said apparatus.

7. The apparatus set forth in claim 5 wherein:

one of said stop means on said piston rod means includes means for engagement with said additive fluid piston means to close said passage means in said additive fluid piston means from interconnecting said additive fluid chambers.

8. The apparatus set forth in claim 5 wherein:

said additive fluid piston means includes seal means mounted thereon and engageable with the bore wall of said additive fluid cylinder means to prevent displacement of said additive fluid piston means in said additive fluid cylinder means except when said additive fluid piston means is engaged by one of said stop means.

9. The apparatus set forth in claim 1 including:

bypass passage means in said housing and bypass valve means interposed in said bypass passage means for selectively bypassing primary fluid direction from said inlet passage to said discharge passage.

10. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores of different diameters, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means for displacing a quantity of additive fluid from said additive fluid cylinder means for injection into said primary fluid;

piston rod means interconnecting said piston assembly with said additive fluid piston means for reciprocation with said piston assembly;

first and second valves associated with said piston assembly and movable to respective positions to place said first and second chambers in communication with each other and close off communication between said second and third chambers and alternately close off said first chamber from said second chamber while communicating said second chamber with said third chamber;

means for moving said valves between said positions and biasing said valves in said positions, respectively, including a shaft disposed on said piston assembly for reciprocation relative to said piston assembly to move said valves between said positions, and toggle means including link means interconnecting said shaft with said piston assembly and spring means associated with said link means for biasing said shaft in a selected one of opposite directions in response to said link means moving through an unstable positions between opposed stable positions of said link means corresponding to said positions of said valve means, respectively, said shaft including means engageble with said housing to initiate movement of said shaft in opposite directions in response to movement of said shaft with said piston assembly toward opposed limit positions of said piston assembly, said first valve means comprising a first closure member slidably mounted on said shaft and movable between open and closed positions relative to said piston assembly to provide for conducting primary fluid from said first chamber to said second chamber.

11. The apparatus set forth in claim 10 wherein:

said toggle means includes means forming a lost motion coupling between said shaft and said link means for imparting an impact force to said shaft when said link means moves toward a stable position to move said first closure member toward one of said open and closed positions, respectively.

12. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores of different diameters, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing and piston rod means connected to said piston assembly;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means and dividing said additive fluid cylinder means into first and second additive fluid chambers, said additive fluid piston means being slidably mounted on said piston rod means and including passage means interconnecting said additive fluid chambers in at least one position of said additive fluid piston means, spaced apart stop means on said piston rod means for reciprocating said additive fluid piston means through an additive fluid intake and delivery stroke to effect displacement of a predetermined charge of additive fluid into said primary fluid during a reciprocating stroke cycle of said piston assembly, one of said stop means including means for engagement with said additive fluid piston means to close said passage means in said additive fluid piston means from interconnecting said additive fluid chambers, and spacer means removably mountable on said piston rod means between said additive fluid piston means and one of said stop means for selectively varying the displacement of said additive fluid piston means to vary the charge of additive fluid injected into said primary fluid during a delivery stroke of said additive fluid piston means;

first and second valves associated with said piston assembly and movable to respective positions to place said first and second chambers in communication with each other and close off communication between said second and third chambers and alternately close off said first chamber from said second chamber while communicating said second chamber with said third chamber; and

means for moving said valves between said positions and biasing said valves in said positions, respectively, said piston assembly, said additive piston means and said means for moving said valves being arranged generally along a central axis of said piston rod means for causing forces acting on said piston assembly to reciprocate said additive fluid piston means to be directed substantially along said axis.

13. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing and piston rod means connected to said piston assembly;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means and dividing said additive fluid cylinder means into first and second additive fluid chambers, said additive fluid cylinder means including valve means for admitting additive fluid to said first additive fluid chamber, said additive fluid piston means being slidably disposed on said piston rod means and including passage means interconnecting said additive fluid chambers in at least one position of said additive fluid piston means, said piston rod means including means for reciprocating said additive fluid piston means through an additive fluid intake and delivery stroke of said additive fluid piston means, respectively, to effect displacement of predetermined charge of additive fluid into said primary fluid during a reciprocating stroke cycle of said piston assembly;

spaced apart stop means on said piston rod means engageable with said additive fluid piston means, one of said stop means including seal means engageable with said additive fluid piston means during a delivery stroke of said additive fluid piston means to close said passage means in said additive fluid piston means from interconnecting said additive fluid chambers, and spacer means removably mounted on said piston rod means between said additive fluid piston means and one of said stop means for selectively varying the displacement of said additive fluid piston means to vary the charge of additive fluid injected into said primary fluid during a delivery stroke of said additive fluid piston means;

valve means associated with said piston assembly and movable to respective positions to place said first and second chambers in communication with each other and close off communication between said second and third chambers and alternately close off said first chamber from said second chamber while communicating said second chamber with said third chamber;

means for yieldably biasing said valve means in said positions, respectively; and

means forming an additive fluid injection passage in communication with said additive fluid cylinder means and said discharge passage for injecting additive fluid into said primary fluid downstream of said first chamber in the direction of flow of primary fluid through said apparatus.

14. The apparatus set forth in claim 13 wherein:

said additive fluid piston means includes seal means mounted thereon and engageable with the bore wall of said additive fluid cylinder means to prevent displacement of said additive fluid piston means in said additive fluid cylinder means except when said additive fluid piston means is engaged by one of said stop means.

15. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

valve means movable in response to movement of said piston assembly to place said first and second chambers in communication with each other and close off communication between said second and third chambers and alternately close off said first chamber from said second chamber while communicating said second chamber with said third chamber;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means and dividing said additive fluid cylinder means into first and second additive fluid chambers and for displacing a quantity of additive fluid from said additive fluid cylinder means for injection into said primary fluid;

valve means for admitting additive fluid to said first additive fluid chamber;

a piston rod interconnecting said piston assembly with said additive fluid piston means for reciprocation with said piston assembly, said additive fluid piston means being slidably mounted on said piston rod and including passage means interconnecting said additive fluid chambers in at least one position of said additive fluid piston means, spaced apart stop means formed on said piston rod for reciprocating said additive fluid piston means through an additive fluid intake and delivery stroke of said additive fluid piston means, respectively, to effect displacement of a predetermined quantity of additive fluid into said primary fluid during a reciprocating stroke cycle of said piston assembly; and

spacer means removably mountable on said piston rod between said additive fluid piston means and one of said stop means for selectively varying the displacement of said additive fluid piston means to vary the charge of additive fluid injected into said primary fluid during a delivery stroke of said additive fluid piston means.

16. The apparatus set forth in claim 15 wherein:

said additive fluid piston means includes seal means mounted thereon and engageable with the bore wall of said additive fluid cylinder means to prevent displacement of said additive fluid piston means in said additive fluid cylinder means except when said additive fluid piston means is engaged by one of said stop means.

17. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores of different diameters, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means for displacing a quantity of additive fluid from said additive fluid cylinder means for injection into said primary fluid;

piston rod means interconnecting said piston assembly with said additive fluid piston for reciprocation with said piston assembly;

first and second valves associated with said piston assembly and movable to a first position to place said first and second chambers in communication with each other and close off communication between said second and third chambers and to a second position to close off said first chamber from said second chamber while communicating said second chamber with said third chamber; and

means for moving said valves between said positions and yieldably biasing said valves in said positions, respectively, including a shaft coaxial with said piston rod means and disposed on said piston assembly for reciprocation relative to said piston assembly to move said valve means between said positions, and toggle means for urging said shaft into respective ones of said positions in response to movement of said shaft, said toggle means including link means interconnecting said shaft with said piston assembly and spring means associated with said link means for biasing said shaft in a selected one of opposite directions in response to said link means moving through an unstable position between opposed stable positions corresponding to said first and second positions of said valve means, said toggle means including means forming a lost motion coupling between said shaft and said link means for imparting an impact force to said shaft when said link means moves toward a stable position to move said valve means toward one of said positions, respectively, and said shaft including means engageable with said housing to initiate movement of said shaft in opposite directions in response to movement of said shaft with said piston assembly toward opposed limit positions of said piston assembly.

18. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores of different diameters, a differential motor piston reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said motor piston;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means for displacing a quantity of additive fluid from said additive fluid cylinder means for injection into said primary fluid;

piston rod means interconnecting said motor piston with said additive fluid piston for reciprocation with said motor piston;

a shaft disposed on and coaxial with said motor piston, an over center mechanism connected to said shaft for biasing said shaft in two limit positions relative to said motor piston, a first valve closure member cooperable with said motor piston for movement between open and closed positions for controlling fluid flow between said first and second chambers, said first closure member being disposed on and slidable relative to said shaft and movable by said shaft between said open and closed positions, second valve closure means connected to said first closure member for movement with said first closure member and cooperable with said motor piston to provide for fluid flow between said second and third chambers when said first closure member has closed off fluid flow between said first and second chambers and closing off fluid flow between said second and third chambers when said first closure member opens to provide for fluid flow between said first and second chambers.

19. Apparatus for injecting a predetermined quantity of fluid additive into a primary fluid stream comprising:

a housing defining first and second cylinder bores, a differential piston assembly reciprocably disposed in said bores and forming first, second and third fluid chambers in said housing;

an inlet passage in said housing for conducting primary fluid under pressure to said first chamber to act on said piston assembly;

a discharge passage in said housing for conducting primary fluid from said second and third chambers from said apparatus;

valve means operable to place said first and second chambers in communication with each other and close off communication between said second and third chambers and alternately close off said first chamber from said second chamber while communicating said second chamber with said third chamber;

additive fluid cylinder means and additive fluid piston means reciprocably disposed in said additive fluid cylinder means and dividing said additive fluid cylinder means into first and second additive fluid chambers and for displacing a quantity of additive fluid from said additive fluid cylinder means for injection into said primary fluid;

means for admitting additive fluid to said first additive fluid chamber;

a piston rod interconnecting said piston assembly with said additive fluid piston means for reciprocation with said piston assembly, said additive fluid piston means being slidably mounted on said piston rod, spaced apart stop means on said piston rod for reciprocating said additive fluid piston means through an additive fluid intake stroke and an additive fluid delivery stroke of said additive fluid piston means, respectively, to effect displacement of a predetermined quantity of additive fluid into said primary fluid during a reciprocating stroke cycle of said piston assembly; and

means associated with at least one of said stop means for selectively varying the displacement of said additive fluid piston means to vary the charge of additive fluid injected into said primary fluid during a delivery stroke of said additive fluid piston means.