Method & apparatus for metering flow of a two-component dispensing system

• US 5,332,125 A
• Filed: 09/10/1992
• Issued: 07/26/1994
• Est. Priority Date: 01/11/1991
• Status: Expired due to Fees

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Noss, Jeffrey, Schmitkons, James W.
• Primary Examiner(s): Bollinger, David H.
• Application Number:
  US07/943,105
• Time in Patent Office: 684 Days
• Field of Search: 222/135, 222/145, 222/129, 222/63, 222/55, 222/54, 222/52, 222/146.2, 222/146.5, 222/1
• US Class Current: 222/1
• CPC Class Codes: B01F 23/40 Mixing liquids with liquids; Emulsifying
• CPC Class Codes: B01F 25/431 Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
• CPC Class Codes: B01F 35/2115 Temperature
• CPC Class Codes: B01F 35/882 using measuring chambers, e.g. volumetric pumps, for feeding the substances
• CPC Class Codes: B29B 7/325 Static mixers in general B01F25/42
• CPC Class Codes: B29B 7/726 Measuring properties of mixture, e.g. temperature or density B29B7/724 takes precedence
• CPC Class Codes: B29B 7/728 Measuring data of the driving system, e.g. torque, speed, power, vibration B29B7/724 takes precedence
• CPC Class Codes: B29B 7/7419 with static or injector mixer elements
• CPC Class Codes: B29B 7/7433 Plants
• CPC Class Codes: B29B 7/7605 having additional mixing arrangements B29B7/7673 takes precedence
• CPC Class Codes: B29B 7/7615 characterised by arrangements for controlling, measuring or regulating, e.g. for feeding or proportioning the components
• CPC Class Codes: B29K 2105/0097 Glues or adhesives, e.g. hot melts or thermofusible adhesives
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence

Abstract

A method and apparatus for mixing and dispensing two different polymeric materials which react chemically with one another when combined by supplying each material to a common dispenser where the materials are mixed and dispensed, which method and apparatus is operative to maintain substantially steady state flow pressures of the materials at the inlets to the dispenser when flow is terminated such that upon restarting of the flow, the steady state volumetric ratio of materials is immediately reestablished and maintained. The method and apparatus includes two metering pumps for individually supplying the liquid materials to the dispenser and means for varying the speeds of the pumps in response to changes in temperature of the materials so as to maintain a fixed mass ratio of the materials to the dispenser.

Claims

1. A mixing and dispensing system for mixing and dispensing at least two different polymeric materials which react chemically with one another when combined, said system comprising

a dispenser having a plurality of liquid flow inlets and an outlet,

first and second pump means for supplying a different liquid polymeric material to each of said liquid flow inlets of said dispenser at a steady state flow and a steady state pressure;

control means for controlling the pressure of at least one of said liquid materials at one of said inlets of said dispenser when said steady state flow of said materials through said dispenser is terminated as a predetermined function of said steady state pressure which was maintained during said steady state flow of both said materials through said dispenser, said control means including a bypass flow path around at least one of said first and second pump means and an adjustable pressure regulator means for regulating the pressure in said bypass flow path.

2. The system of claim 1 in wherein said control means is operable to maintain the inlet pressure of at least two of said different liquid materials at said dispenser after the flow of materials through said dispenser is terminated as a predetermined function of said steady state pressure which was maintained at said dispenser when said materials were flowing through said dispenser.

3. A two-component mixing and dispensing system for mixing and dispensing two different polymeric materials which react chemically with one another when combined, said system comprising

a two-component dispenser having a pair of liquid flow inlets and a single outlet,

first supply means including a first metering pump for supplying a first liquid polymeric material to one of said liquid flow inlets of said dispenser at a first pressure;

second supply means including a second metering pump for supplying a second liquid polymeric material to the other of said liquid flow inlets of said dispenser at a second pressure, and

control means for controlling said first pressure of at least said first liquid supply to said one of said inlets of said dispenser, both when said materials are flowing through said dispenser and when said flow of materials through said dispenser is terminated, so that upon and subsequent to startup of flow of said liquid materials through said dispenser the volume of said first liquid material flowing through said dispenser remains substantially constant at a predetermined flow rate, said control means including a bypass flow path around flow rate, said control means including a bypass flow path around said first metering pump and an adjustable pressure regulator means for regulating the pressure in said bypass flow path.

4. A two-component mixing and dispensing system for mixing and dispensing two different polymeric materials which react chemically with one another when combined, said system comprising

a two-component dispenser having a pair of liquid flow inlets and a single outlet,

first supply means including a first metering pump for supplying a first pressurized, liquid polymeric material to one of said liquid flow inlets of said dispenser,

second supply means including a second metering pump for supplying a second pressurized, liquid polymeric material to the other of said liquid flow inlets of said dispenser, and

contol means for maintaining the flow rate of at least said first liquid downstream of said first metering pump at a predetermined flow rate both when said materials are flowing through said dispenser and when said flow of materials through said dispenser is terminated so that upon and subsequent to startup of flow of said liquid materials through said dispenser, the volume of said first liquid material flowing through said dispenser remains substantially constant, said control means including a bypass flow path around said first metering pump and an adjustable pressure regulator means for regulating the pressure in said bypas flow path.

5. A two-component mixing and dispensing system for mixing two different polymeric materials which react chemically with one another when combined and for dispensing a resultant mixture thereof, which system comprises:

a two-component dispenser,

first supply means for supplying a first liquid polymeric material to said dispenser at a first pressure, said first supply means including a first source of said first material and first conduit means for interconnecting said first source to said dispenser, said first conduit means further including a first metering pump for supplying measured quantities of said first material through said first conduit means to said dispenser,

second supply means for supplying a second liquid polymeric material to said dispenser at a second pressure, said second supply means including a second source of said second material and second conduit means for interconnecting said second source to said dispenser, said second conduit means further including a second metering pump for supplying measured quantities of said second material through said second conduit means to said dispenser, and

pressure control means, operable when the flow of materials through said dispenser is terminated, for controlling the pressure at which at least the first pressurized liquid material is supplied to said dispenser as a function of the pressure when said liquid materials are flowing through said dispenser, said pressure control means including a bypass flow path around said first metering pump and an adjustable pressure regulator means for regulating the pressure in said bypass flow path.

6. The system of claim 5 wherein said pressure control means is operable to maintain the inlet pressure of both said first and second liquid materials at substantially constant predetermined flow pressures both when said liquid materials are flowing through said dispenser and when said flow of materials through said dispenser is terminated.

7. The system of claim 5 in which said pressure control means includes

bypass flow paths around each of said first and second metering pumps, and

an adjustable pressure regulator means in each of said bypass flow paths.

8. The system of claim 7 wherein each supply means further includes a first flow control valve connected to one of said conduit means;

and wherein

said pressure control means further includes a second flow control valve in each bypass flow path and a means for alternating opening said respective first and second flow control valves so that flow is routed through said each bypass flow path and around each of said metering pumps when said first flow control valves are closed and said second flow control valves are opened and flow is routed to said first flow control valve and through said dispenser when said first flow control valves are opened and said second flow control valves are closed.

9. The system of claim 5 wherein the first supply means further includes a first flow control valve connected to said first conduit means;

said bypass flow path including a second flow control valve; and

means for alternating opening said first and second flow control valves so that flow is routed through said bypass flow path and around said metering pump when said first flow control valve is opened and said second flow control valve is closed and flow is routed to said first flow control valve and through said dispenser when said first flow control valve is opened and said second flow control valve is closed.

10. The system of claim 6 wherein said pressure control means is operable to maintain substantially constant the entering pressure of both said first and second liquid materials at said dispensers both when the flow of liquid materials through said dispenser is stopped, as well as during the steady state flow condition of liquid materials through said dispenser.

11. A method of mixing and dispensing different polymeric materials which react chemically with one another when combined, which method comprises:

supplying a first pressurized liquid polymeric material to said dispenser,

supplying a second pressurized liquid polymeric material to said dispenser,

intermittently starting and stopping the flow of said materials from said dispenser, and

controlling the supply of at least one of said liquid materials to said dispenser so that said at least one liquid material flows at a steady state flow pressure when said materials are flowing through said dispenser and at an adjustably regulated pressure which is determined by an adjustable pressure regulator contained in a bypass flow path for said at least one liquid material and is a predetermined function of said steady state flow pressure when said flow of materials through said dispenser is terminated.

12. A method of mixing and dispensing different polymeric materials which react chemically with one another when combined, which method comprises:

supplying a first pressurized liquid polymeric material to a dispenser,

supplying a second pressurized liquid polymeric material to said dispenser,

intermittently starting and stopping the flow of said materials from said dispenser, and

controlling the steady state flow pressures at which both said first and second liquid materials are inlet to said dispenser when said liquid materials are flowing through said dispenser, and controlling the inlet pressure of each of said first and second materials by adjustably regulating each inlet pressure to a pressure which is determined by adjustable pressure regulators contained in bypass flow paths for said first and second liquid materials and is a predetermined function of said steady state flow pressures when said flow of materials through said dispenser is terminated.

13. A method of mixing and dispensing comprising the steps of:

a) intermittently dispensing a mixture of a first and second pressurized liquid polymeric material from an outlet of a dispenser;

a) intermittently dispensing a mixture of a first and second pressurized liquid polymeric material from an outlet of a dispenser;

b) determining a steady state inlet pressure for each liquid polymeric material to the dispenser when said mixture is dispensing under steady state flow conditions; and

c) adjustably regulating an off inlet pressure as a function of the respective steady state inlet pressures of each liquid polymeric material when said mixture is not being dispensed from the dispenser by directing said first and second liquid polymeric materials through respective first and second bypass flow paths each including an adjustable pressure regulator.

14. The method of claim 13 wherein the off inlet pressure of each liquid polymeric material of step (c) is substantially equal to the respective steady state inlet pressure.

15. The method of claim 13 wherein the inlet pressure of each liquid polymeric material of step (c) is a multiple of the respective steady state inlet pressure.

16. The method of claim 15 wherein the inlet pressure of each liquid is within the range of 0.7 and 1.3 times the respective steady inlet pressure.

17. A method for mixing and dispensing different polymeric materials comprising the steps of:

a) dispensing a resultant mixture of a first and second liquid polymeric material while maintaining a respective first supply pressure for each liquid polymeric material;

b) determining a respective second supply pressure for each liquid polymeric material in a predetermined relationship to the respective first supply pressure for each liquid polymeric material;

c) adjustably regulating said second supply pressure of at least one of said first and second liquid polymeric materials to a second supply pressure different from said first supply pressure of said one of said first and second liquid polymeric materials by directing said one of said first and second liquid polymeric materials through a bypass flow path including an adjustable pressure regulator;

d) stopping the dispensing of the resultant mixture while maintaining respective second supply pressures and;

e) repeating steps (a) through (d).

18. A mixing and dispensing system for mixing and dispensing at least two different polymeric materials which react chemically with one another when

a dispenser having a plurality of liquid flow inlets and an outlet,

supply means for supplying a different pressurized, liquid polymeric material to each of said liquid flow inlets of said dispenser,

means for maintaining a fixed mass ratio of said liquid materials supplied to said inlets of said dispenser by varying the volume of each material supplied to said inlets in response to temperature changes of said materials.

19. The system of claim 18 wherein said last named means is further operable to control the inlet pressure of each of said liquid materials at said dispenser after the flow of materials through said dispenser is terminated so that said inlet pressures are a predetermined function of the pressure which was maintained at said dispenser when said materials were flowing through said dispenser.

20. A two-component mixing and dispensing system for mixing two different polymeric materials which react chemically with one another when combined, and for dispensing a resultant mixture thereof, said system comprising

a two-component dispenser having a pair of liquid flow inlets and an outlet,

first supply means for supplying a first pressurized, liquid polymeric material to one of said liquid flow inlets of said dispenser,

second supply means for supplying a second pressurized, liquid polymeric material to the other of said liquid flow inlets of said dispenser,

control means for establishing and controlling the flow rate of said first and second liquid materials supplied to said inlets of said dispenser at a predetermined flow rate during startup of said dispenser, while also maintaining the flow rate of the resulting mixture being dispensed from the outlet of the dispenser at another predetermined flow rate, and

said control means including means for maintaining a fixed mass ratio of said liquid materials supplied to said inlets of said dispenser by varying the volume of each of said materials supplied to said inlets in response to temperature changes of said respective materials.

21. A two-component mixing and dispensing system for mixing and dispensing two different polymeric materials which react chemically with one another when combined, said system comprising

a two-component dispenser having a pair of liquid flow inlets and a single outlet,

first supply means including a first metering pump for supplying a first pressurized, liquid polymeric material to one of said liquid flow inlets of said dispenser,

second supply means including a second metering pump for supplying a second pressurized, liquid polymeric material to the other of said liquid flow inlets of said dispenser,

control means for controlling the pressure of at least said first liquid supplied to said one of said inlets of said dispenser, both when said materials are flowing through said dispenser and when said flow of materials through said dispenser is terminated, so that upon and subsequent to startup of flow of said liquid materials through said dispenser the volume of said first liquid material flowing through said dispenser remains substantially constant at a predetermined flow pressure, and

said control means including means for maintaining a fixed mass ratio of said liquid materials supplied to said inlets of said dispenser by varying the volume of said materials supplied to said inlets in response to temperature changes of said materials.

22. The system of claim 21 wherein said control means is operable to establish and maintain the flow rate of said first liquid material supplied to said one of said inlets at a predetermined flow rate during startup of said dispenser.

23. A two-component mixing and dispensing system for mixing and dispensing two different liquid polymeric materials which react chemically with one another when combined, said system comprising

a two-component dispenser having a pair of liquid flow inlets and a single outlet,

first supply means including a first metering pump for supplying a first pressurized, liquid polymeric material to one of said liquid flow inlets of said dispenser,

second supply means including a second metering pump for supplying a second pressurized, liquid polymeric material to the other of said liquid flow inlets of said dispenser,

means for maintaining the flow rate of said liquid materials through said metering pumps at predetermined flow rates both when said materials are flowing through said dispenser and when said flow of materials through said dispenser is terminated so that upon and subsequent to startup of flow of said liquid materials through said dispenser, the volume of said first liquid material flowing through said dispenser remains substantially constant, and

said last named means including means for maintaining a fixed mass ratio of said liquid materials supplied to said inlets of said dispenser by varying the volume of said materials supplied to said inlets in response to temperature changes of said materials.

24. The system of claim 23 wherein said flow rate maintenance means is operable to vary the speed of said metering pumps in response to temperature changes of said materials at said metering pumps.

25. The method of mixing and dispensing two different liquid materials while maintaining a fixed mass ratio of the materials as they are mixed and combined, which materials when combined chemically react with one another, which method comprises,

supplying a first pressurized liquid material to a first metering pump and from the first metering pump to a dispenser,

supplying a second pressurized liquid material to a second metering pump and from the second metering pump to a dispenser,

combining and initiating a chemical reaction of said materials at said dispenser, and

maintaining a fixed mass ratio of said materials supplied to said dispenser by varying the volume of each material supplied to said dispenser by said metering pumps in response to temperature changes of said materials.

26. The method of claim 25 which includes measuring the temperature of said materials at said metering pumps, and

varying the speeds of said pumps in response to temperature measurements at said pumps.

27. The method of mixing and dispensing two different liquid materials while maintaining a fixed mass ratio of the materials as they are mixed and combined, which materials when combined react chemically with one another, which method comprises,

supplying a first pressurized liquid material to a first metering pump and from the first metering pump to a dispenser,

combining and initiating a chemical reaction of said materials,

measuring the temperature of each of said materials, and

varying the speed of said metering pumps in response to changes of temperature of said liquid materials so as to maintain a fixed mass ratio of said materials and a fixed flow rate of said combined materials dispensed from said dispenser.

28. The method of claim 27 wherein said temperature of said liquid materials is measured at said metering pumps.

29. The method of claim 27 wherein said fixed flow rate of said combined materials from said dispenser is a fixed volumetric flow rate.

30. The method of claim 27 wherein said fixed flow rate of combined materials from said dispenser is a fixed volumetric flow rate, and the volumetric flow rate of said first liquid material to said dispenser is determined by the equation ##EQU3## and the volumetric flow rate of said second liquid material to said dispenser is determined by the equation ##EQU4## where Rm is the mass ratio of said liquid materials, Fv is the total volumetric flow rate of both said liquid materials, Fv₁ is the volumetric flow rate of said first liquid material, Fv₂ is the volumetric flow rate of said second liquid material, SG₁ is the specific gravity of said first liquid material, and SG₂ is the specific gravity of said second liquid material.

31. The method of claim 27 wherein said fixed flow rate of said combined materials from said dispenser is a fixed mass flow rate.

32. The method of claim 27 wherein said fixed flow rate of said combined materials from said dispenser is a fixed mass flow rate and the volumetric flow rate of said first liquid material to said dispenser is determined by the equation ##EQU5## and the volumetric flow rate of said second liquid material to said dispenser is determined by the equation ##EQU6## where Rm is the mass ratio of said liquid materials, Fm is the total mass output flow rate, Fv₁ is the volumetric flow rate of said first liquid material, Fv₂ is the volumetric flow rate of said second liquid material, SG₁ is the specific gravity of said first liquid material, and SG₂ is the specific gravity of said second liquid material.

33. A method of mixing and dispensing different polymeric materials which react chemically with one another when combined, which method comprises

supplying a first pressurized liquid polymeric material via a first metering pump to said dispenser,

supplying a second pressurized liquid polymeric material via a second metering pump to said dispenser,

intermittently starting and stopping the flow of said materials from said dispenser,

controlling the steady state flow pressures at which each of said liquid materials are inlet to said dispenser when said materials are flowing through said dispenser, and controlling the inlet pressure of each of said first and second materials as a predetermined function of said steady state flow pressures when said flow of materials through said dispenser is terminated, and

maintaining a fixed mass ratio of said materials and a fixed flow rate of said combined materials dispensed from said dispenser by varying the speed of said metering pumps in response to a change in temperature of said materials.

34. A method of mixing and dispensing comprising the steps of:

a) supplying first and second pressurized liquid polymeric materials via first and second metering pumps to a dispenser and intermittently dispensing a mixture of said first and second pressurized liquid polymeric materials from an outlet of said dispenser;

b) determining a steady state inlet pressure for each liquid polymeric material to the dispenser when said mixture is dispensing under steady state flow conditions;

c) determining and maintaining an off inlet pressure as a function of the respective steady state inlet pressures of each liquid polymeric material when said mixture is not being dispensed from the dispenser; and

d) maintaining a fixed mass ratio of said materials and a fixed flow rate of said combined materials dispensed from said dispenser by varying the speed of said metering pumps in response to a change in temperature of said materials.