Method and apparatus for precision pumping, ratioing, and dispensing of work fluid(s)

• US 5,100,699 A
• Filed: 01/17/1990
• Issued: 03/31/1992
• Est. Priority Date: 08/24/1989
• Status: Expired due to Fees

• Current Assignee: Graco Incorporated
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Roeser, John O.
• Primary Examiner(s): Lawrence, Evan
• Application Number:
  US07/466,669
• Time in Patent Office: 804 Days
• Field of Search: 222/53, 222/55, 222/63, 222/1, 118/610, 118/697, 118/50, 118/302, 118/315, 118/323, 118/612, 427/256, 427/294
• US Class Current: 427/256
• CPC Class Codes: B29B 7/749 with stirring means for the individual components before they are mixed together
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder

Abstract

For conveying and for dispensing of degassed work liquid(s), an apparatus and a method for precision conveying and/or ratioing and/or mixing and/or dispensing of work liquids are presented using a pump of a positive displacement, high precision, piston/cylinder constant flush type with piston smaller than the chamber. The piston is programmably advanced along a stroke with tiny repeatable adjustable steps. Infinitely adjustable precision ratioing and/or programmable mixing of degassed materials may be provided downstream of the pump outlets when degassed liquids are presented to the inlets of two such pumps. The mixing occurs in a mixing chamber, the output of which is then used. The vacuum degassed work liquids may be dispensed in a system which features the creation and maintenance of a positive absolute pressure on the work liquids throughout, from the point of exiting a first degassing chamber to an end use at a dispensing outlet. This occurs whether the degassed liquid is moved along the flow path through the precision dispensing pumps or other types of pumps and prevents unwanted entrainment of gases. Available software and adjustable programmable precision hardware are used in the system, and features use of widely available personal computers. Precision relative location and/or movement of workpieces and dispensing outlet(s) are provided. Further degassing of the work liquid(s) may be provided by dispensing in a vacuum chamber.

Claims

1. The method of precision dispensing a degassed liquid onto a workpiece comprising:

a) delivering a non-degassed first work liquid to a first chamber maintained at below atmospheric pressure where said first work liquid is agitated to cause substantially all gases therwithin to be removed therefrom and from said first chamber,

b) removing the substantially degassed first work liquid from said first chamber by a means which creates and maintains a positive hydraulic pressure which is above atmospheric pressure on said first work liquid for moving same through substantially sealed passageways to a dispensing outlet after routing through positive displacement precision programmable dispensing pump means in said substantially sealed passageways;

c) actuating the programmable precision pump means to cause a measured amount of said first work liquid to continue to move under a positive hydraulic pressure above atmospheric pressure for delivery of the said first work liquid through said dispensing outlet onto a workpiece;

whereby the maintaining of the first work liquid at a hydraulic pressure above atmospheric pressure intermediate the first vacuum chamber and said dispensing outlet prevents entrainment of deleterious gases in the said first work liquid as it moves therebetween while affording precision dispensing.

2. The method set forth in claim 1 wherein there is a dispensing chamber containing the dispensing outlet, said dispensing chamber being selectively operable to be maintained at less than atmospheric pressure, wherein there is employed the additional step of maintaining less than atmospheric pressure in the dispensing chamber when said first work liquid is being dispensed through said dispensing outlet onto said workpiece.

3. The method of claim 2 wherein the flow of said first work liquid through the dispensing outlet in the dispensing chamber is further controlled by the step of selectively and programmably pinching together or relieving the pinching together of a flexible sealed passageway intermediate the programmable precision pump means and the dispensing outlet.

4. The method set forth in claim 3 wherein the ambient pressure in said dispensing chamber is selectively maintained at a positive absolute pressure less than atmospheric pressure and subsequent to selectively shutting of flow of said first work liquid by pinching, there is created an absolute pressure adjacent to the place of pinching which is less than the absolute pressure in said dispensing chamber whereby to create a such back of said first work liquid at the dispensing outlet.

5. The method set forth in claim 4 wherein work pieces and the dispensing outlet are moveable relative to each other in the dispensing chamber in programmed relationship to the actuation of the precision pump means and the pinching and relieving the pinching together of the flexible sealed passageway, so that said first work liquid being dispensed is deposited in selectively variable amounts and preselected locations relative to the workpieces.

6. The method set forth in claim 1 wherein the programmable precision pump means comprises a reciprocal piston movable relative to a cylinder with a predetermined length of stroke wherein the method of dispensing the said first work liquid is characterized as utilizing the steps of forcing said first work liquid form said dispensing outlet by causing interrupted discrete starting and stopping short movements of the piston while moving the piston in a single direction, with the length of the individual discrete movements being less than total length of stroke of said piston.

7. The method set forth in claim 6 wherein the interior wall of the cylinder is meaningfully larger than the piston to permit flow of said first work liquid along said interior wall and past the radial outer work surface of the piston said steps of forcing the flow of first work liquid from the said dispensing outlet being further characterized as having the flow moving past the interior wall and the radial outer work surface with a turbulent flushing action, and the radial outer work surface of the piston is reciprocatingly moved into and out of the cylinder with a suitable bearing means in a manner to provide a liquid solvent bath for the piston whereby the piston is bathed in a work liquid solvent on every reciprocal movement of the piston.

8. The method set forth in claim 1 wherein there are the additional steps of:

a) parallel to said activities with said first work liquid, the delivering of a non degassed second work liquid to a second chamber maintained at below atmospheric pressure where said second work liquid is agitated to cause substantially all gases therewithin to be removed therefrom and from said second chamber,

b) removing the substantially degassed second work liquid from said second chamber by a second means which creates and maintains a positive hydraulic pressure which is above atmospheric pressure on said second work liquid for moving same through substantially sealed passageways to said dispensing outlet through a mixing manifold means and through a second positive displacement precision programmable dispensing pump means,

c) actuating the second programmable precision pump means in times programmed relationship to said first programmable precision pump means to cause a measured amount of the second work liquid to continue to move under a positive hydraulic pressure above atmospheric pressure through said mixing manifold means for mixing with said first work liquid for delivery of the liquid through the said dispensing outlet,

whereby the maintaining of both the first and second work liquids at a hydraulic pressure above atmospheric pressure intermediate the respective first and second vacuum chambers and said dispensing outlet prevents entrainment of deleterious gases in both the first and second work liquids as they move therebetween while providing precise ratioing of the first and second work liquids each to the other.

9. Apparatus for precision dispensing a degassed first work liquid onto a workpiece comprising in combination, first chamber means having chamber outlet means, means for delivering a first non degassed work liquid to said first chamber means, means for maintaining said first chamber means at below atmospheric pressure, first means for agitating said first work liquid located in said first chamber means and operable to cause substantially all gasses therewithin to be dissociated from said first work liquid, first positive removal means for removing the substantially degassed first work liquid from said first chamber means said first positive removal means being operable to create and maintain a positive hydraulic pressure which is above atmospheric pressure on said first work liquid at said chamber outlet means, substantially sealed passageways connected to said chamber outlet means and terminating in a dispensing outlet means, first programmable dispensing pump means located within said substantially sealed passageways intermediate to said chamber outlet means and said dispensing outlet means, means for actuating said first programmable dispensing pump means operable to cause programmed amounts of said first work liquid to continue to move under a positive hydraulic pressure above atmospheric pressure for delivery of the said first work liquid through said dispensing outlet means onto a workpiece, whereby the maintaining of the said first work liquid at a hydraulic pressure above atmospheric pressure intermediate the chamber outlet means and said dispensing outlet means by said first positive removal means prevents entrainment of deleterious gases in the first work liquid as it moves therebetween in said substantially sealed passageways.

10. The apparatus set forth in claim 9 further comprising a dispensing chamber means containing said dispensing outlet means, programmable control means for said dispensing chamber means, said programmable control means being selectively operable to cause said dispensing chamber means to be maintained at less than atmospheric pressure when the said first work liquid is being dispensed.

11. Apparatus of claim 10 further comprising moveable pinch valve means located in said substantially sealed passageway means intermediate said first programmable dispensing pump means and the dispensing outlet means, said movable pinch valve means being operable to control the flow of work liquid through the dispensing outlet means in said dispensing chamber means, said programmable dispensing pump means being further characterized as being of a reciprocating type of positive displacement precision programmable pump means.

12. The apparatus set forth in claim 11 wherein said movable pinch valve means has a flexible sealed passageway and pinching means, said pinching means being selectively and programmably operable to pinch together or relieve the pinching together of said flexible sealed passageway to thereby stop and start the dispensing of said first work liquid through said dispensing outlet means.

13. The apparatus set forth in claim 12 wherein said pinching means is operable to move toward upstream of the flow direction of the said first work liquid after pinching together of said flexible sealed passageway while maintaining said sealed passageway in pinched together orientation to provide suck back of the said first work liquid at the dispensing outlet means.

14. The apparatus set forth in claim 13 wherein said programmable control means for said dispensing chamber means is operable to selectively maintain the ambient pressure in said dispensing chamber means at a preselected positive absolute pressure less than atmospheric pressure, and said movable pinch valve means is operable to create a second absolute pressure in said flexible sealed passageway adjacent to the place of pinching, said second absolute pressure being less than the preselected absolute pressure in said dispensing chamber means, whereby the preselected positive absolute pressure less than atmospheric in said dispensing chamber means being greater than said second absolute pressure affords a suck back of said first work liquid at the said dispensing outlet means.

15. The apparatus set forth in claim 12 further comprising workpieces means for programmable moving work pieces within said dispensing chamber means, said means for programmably moving said work pieces being coordinated with said movable pinch valve means and said first positive displacement precision programmable dispensing pump means, said means for programmably moving said work pieces being operable to move said work pieces in said dispensing chamber means when it is maintained at less than atmospheric pressure in coordinated programmed relationship to the actuation of the precision pumps means and the punching and relieving of the pinching together of the flexible sealed passageway of said movable pinch valve means, whereby said first work liquid may be precisely dispensed from the said dispensing outlet means onto multiple work pieces without changing the pressure in said dispensing chamber means.

16. The apparatus set forth in claim 15 wherein said dispensing outlet means comprises means defining multiple outlet orifices mounted in fixed spaced array in said dispensing chamber means, and said means for programmably moving said work pieces comprises work table means operable to both mount multiple sets of multiple work pieces for simultaneous dispensing from said multiple orifices onto a set of work pieces and to move said set work pieces after such dispensing into alignment with a new set of work pieces for sequential dispensing upon said new set of work pieces on said work table means.

17. The apparatus set forth in claim 9 wherein the said first programmable dispensing pump means comprises rotary motor means, reciprocal piston means, cylinder means for coaction with said piston means for precision positive displacement pumping, and ball screw means having a first portion attached to said reciprocal piston means for reciprocating same and a second portion connectable with said rotary motor means, said rotary motor means being operable to programmably repeatably and adjustably stop at any one of more than 100 spaced apart in equal amount positions of one revolution of said rotary motor means to thereby advance and retract said piston a tiny fraction of an inch for each movement between spaced positions.

18. The apparatus set forth in claim 17 wherein said reciprocal piston means has a predetermined length of stroke, said length of stroke being programmably adjustably subdivided into in excess of 1,000 discrete units of movement per inch of travel, whereby several discrete dispensed shots of said first work liquid may be precisely programmably adjustably and selectively delivered from said dispensing outlet means upon a single movement of said reciprocal piston means along its length of stroke.

19. The apparatus set forth in claim 18 further comprising solvent bearing means for receipt of an exterior radial surface of said piston means and wherein said piston means has a forward position and a retracted position, and said solvent bearing means being further characterized as being cooperatively arranged and located adjacent said retracted position of said reciprocal piston means whereby said exterior radial surface of said piston means becomes bathed in solved on every reciprocal movement of said piston means toward said forward position.

20. The apparatus set forth in claim 19 wherein said cylinder means has an inlet and an outlet, said inlet is located adjacent the said forward position of said piston means and the said outlet is located adjacent the said retracted position of said piston means, movable valve means located adjacent the said inlet operable to be open on the retracting movement of said piston means and closed during forward movement of said piston means, whereby said first positive removal means is operable to positively move work fluid into said cylinder means during retracting movement of said piston means.

21. The apparatus set forth in claim 20 wherein said cylinder means has an internal diameter surface and said exterior radial surface of said piston means has an external diameter less than said internal diameter to permit said first work liquid flow around said piston means when said piston means is moving from its retracted toward its forward position, whereby movement of said piston means towards its forward position causes a turbulent flushing movement of said first work fluid in said cylinder means for exit out said outlet.

22. The apparatus set forth in claim 9 wherein said first positive removal means comprises rotary auger means having a portion located within said first chamber means adjacent said chamber outlet means, and a portion sealingly extending exteriorly of said first chamber means, and auger motor means exterior of said first chamber means operable to rotatably drive said auger means within said chamber to positively move said first work liquid in said substantially sealed passageways.

23. The apparatus set forth in claim 9 further including means for simultaneously degassing and mixing a second work liquid with said first work liquid for exit through said dispensing outlet means and comprising mixing means for said first and second work liquids located upstream of said dispensing outlet means, second chamber means having second chamber outlet means, means for delivering said second non-degassed work liquid to said second chamber means, second means for maintaining said second chamber means at below atmospheric pressure, second means for agitating said second work liquid located in said second chamber and operable to cause substantially all gasses therewithin to be dissociated form said second work liquid, second positive removal means for removing the substantially degassed second work liquid from said second chamber means which is operable to create and maintain a positive hydraulic pressure which is above atmospheric pressure on said second work liquid at said second outlet means, said substantially sealed passageways being connected to said second chamber outlet means and terminating in said dispensing outlet means, second programmable dispensing pump means located within said substantially sealed passageways intermediate to said second chamber outlet means and said dispensing outlet means, said second dispensing pump means being operable to cause a programmed amount of said second work liquid to continue to move under a positive hydraulic pressure above atmospheric pressure for delivery of the second work liquid to said mixing means and after mixing with said first work liquid for dispensing of the mixed material through said dispensing outlet means, whereby the maintaining of both said first and second work liquids at a hydraulic pressure above atmospheric pressure intermediate the said first and second chamber outlet means and said dispensing outlet means by said first and second positive removal means prevents entrainment of deleterious gases in the said first and second work liquids as they move therebetween in said substantially sealed passageways.

24. The apparatus set forth in claim 23 wherein said first and second positive removal means each comprise first and second rotary auger means located respectively in said first and second chamber means, each of said first and second auger means being motor driven in a single direction.

25. The apparatus set forth in claim 24 further comprising rotary auger means, associated work fluid first and second temperature sensing means each operable to deliver a temperature dependent electric signal responsive respectively to the variable temperatures of the first and second work fluids being moved by said first and second rotary auger means, first and second heater means operable to heat the respective first and second work fluids in said first and second chamber means adjacent said first and second rotary auger means, adjustable programmable control means operable to be selectively human operator programmed to maintain said first and second work fluids at a selected temperature and operable respectively to cause said first and second heater means to elevate the temperature of said first and second work liquids responsive to the temperature dependent signals respectively received, third and fourth sensor means associated respectively with said first and second programmable dispensing pump means and each operable to respectively sense the temperature of said first and second work fluids at those respective locations and each respectively being operative to give a temperature dependent electric signal to said adjustable programmable control means responsive to the respective temperatures of said first and second work liquids, third and fourth heater means respectively associated with and operable to heat said first and second work liquids at said first and second programmable pump means for changing the temperature of said first and second work liquids, fifth sensing means associated with said mixing means and operable to give a temperature dependent electric signal to said adjustable programmable control means, and fifth heater means associated with said mixer means and operable to elevate the temperature of the mixed first and second work fluids whereby precise dispensing of work liquids whose physical flow characteristics are temperature dependent may be precisely controlled for adjustable repeatable precision dispensing.

26. The apparatus set forth in claim 16 wherein the operations of a group of the components of the apparatus comprised of the:

means for delivering the first non-degassed work liquid;

means for maintaining the first chamber means at below atmospheric pressure;

first means for agitating said first work liquid;

first positive removal means;

first programmable dispensing pump means;

means for actuating the first programmable dispensing pump means;

dispensing outlet means;

dispensing chamber means;

programmable control means;

movable pinch valve means, and means for programmably moving work pieces are each and all controlled from a central source means, said central source means being means operably connected to a human operator programmable computer means, said human operator programmable computer means, when programmed, being operable to control the sequence, duration, cooperation and disablement of the individual components of said group of components in said apparatus.

27. The apparatus set forth in claim 9 further comprising a digital input/output board means having multiple input connection means for receipt of sensed signals and multiple output connection means for giving output commands, said input/output board means being operative to receive condition dependent input signals and to give condition dependent output commands to a group of said component parts of the apparatus comprising:

a) said means for delivering the first non-degassed work liquid,

b) said means for maintaining the first chamber means at below atmospheric pressure,

c) said first means for agitating said first work liquid,

d) said first positive removal means,

e) said first programmable dispensing pump means, and

f) said means for actuating said first programmable dispensing pump means,

wherein each of the components of the group of components (a) through (f) are connected to said of said input connection means or one of said output connection means of said digital input/output board means for interdependent operations of the group of components (a) through (f).

28. The apparatus set forth in claim 27 further comprising an analog input/output board means having a plurality of analog input connection means and analog output connection means, said analog input connection means each being able to receive a range of signal values sensed at a remote location, first heat sensing means associated with said first positive removal means and operable to deliver a range of temperature sensitive/dependent signals to one of said analog input connection means, second heat sensing means associated with said first programmable dispensing pump means and operable to deliver a range of temperature sensitive/dependent signals to another one of said analog input connection means, first heater means associated with said first positive removal means having an off state and a heated state and connected to one of said output connection means of said digital input/output board means, second heater means associated with said first programmable dispensing pump means having an off state and a heated state and connected to another one of said output connected means of said digital input/output board means, said digital and analog input/output board means, first and second heat sensing means and first and second heater means being operatively interconnected to selectively change said first and second heater means from an off state to a heated state, whereby heat map by selectively and controllably delivered to said respective areas adjacent to said first and second heater means when commands are given thereto through said digital input/output board means when said analog input/output board means respectively receives a signal from said first and second sensing means.

29. The apparatus set forth in claim 28 further comprising pressure sensing transducer means associated with said first chamber means and operable to deliver a range of signals to a separate analog input connection means of said analog input/output board, signal connection means connected between (a) said means for maintaining the said first chamber means at below atmospheric pressure and a separate output connection means of said digital input/output board means and (b) between said separate analog input connection means and said separate output connection of said digital input/output board means, whereby said pressure sensing means is operable to deliver a pressure dependent signal to said means for maintaining the said first chamber means below atmospheric pressure to automatically maintain a preselected pressure in said first chamber means.

30. The apparatus set forth in claim 23 wherein said first and second programmable pump means respectively have first and second inlets and first and second outlets, and further including inlet control valve means for said respective first and second programmable dispensing pump means inlets, said inlet control valve means being located intermediate said first and second chamber outlet means and said first and second programmable dispensing pump means and operable to permit and prevent flow of first and second work fluids into said first and second inlets, said inlet control valve means being operatively associated with said dispensing outlet means to prevent flow into said first and second programmable pump means when mixed work liquid are dispensed out said dispensing outlet means.

31. The apparatus set forth in claim 23 further including solvent tank means containing solvent liquid, said solvent tank means being associated with said mixing means, conduit means connected between said solvent tank means and said mixing means, first valve means and second valve means, said first and second valve means being located in said substantially sealed passageways intermediate said mixing means and said first and second programmable dispensing pump means, said first valve means being operable to permit and prevent output flow of said first and second work liquids in said substantially sealed passageways, said second valve means being operable to prevent and permit flow of solvent from said solvent tank means through said conduit means and thereafter through at least a portion of said substantially sealed passageways, said first and second valve means being coordinated and arranged whereby when said first valve means prevents flow, said second valve means permits flow of solvent liquid through said conduit means and said mixing means to said dispensing outlet means to clean at least a portion of said substantially sealed passageways.

32. The apparatus set forth in claim 16 wherein there are multiple pinch valve means, said multiple pinch valve means being located and arranged whereby there is one pinch valve means for controlling each individual outlet orifice of the multiple outlet orifices, each orifice being spacedly located a different flow path length/distance from said mixing means, whereby each outlet orifice may be precisely controlled independent of its mixed first and second work fluids flow path length/distance from said mixing means.