Method and apparatus for controlling the temperature of molds, dies, and injection barrels using fluid media

• US 20060196957A1
• Filed: 02/13/2006
• Published: 09/07/2006
• Est. Priority Date: 02/14/2005
• Status: Active Grant

• Current Assignee: Moldcool International, LLC
• Original Assignee: Moldcool International, LLC
• Inventors: Johnson, Kenneth E.
• Granted Patent: US 8,114,321 B2
• Time in Patent Office: Days
• US Class Current: 237/56
• CPC Class Codes: B29C 2945/76545 Flow rate
• CPC Class Codes: B29C 2945/76782 temperature control fluids
• CPC Class Codes: B29C 35/007 Tempering units for temperature control of moulds or cores, e.g. comprising heat exchangers, controlled valves, temperature-controlled circuits for fluids B29C35/0294 takes precedence
• CPC Class Codes: B29C 45/7306 Control circuits therefor
• CPC Class Codes: G05D 23/1919 characterised by the type of controller

Abstract

Methods and apparatus for controlling the temperature of a mold such as for molding plastics, metal, ceramic, and die-casting. A circulator supporting a molding machine and consisting of a fixed displacement pump being driven by servo stepping motor and speed controlled by standard motor software, provides dynamic, real time flow control for metering of the thermal control fluid to the molding machine with a pre-set and/or adjustable flow rate profile appropriate to the molding machine and process. The pump meters the temperature control fluid to the control loop in precise units of volume, based on selected control inputs that may be based on any one or combination of time, machine cycle status, mold or process temperature, pressure, and flow rate variables, regardless of inlet or outlet loop pressure. It performs positive or negative pressure and various flow behaviors including fixed flow, variable flow, and pulsed flow.

Claims

1. A fluid circulator system for regulating the temperature of a molding machine, the system comprising:

a fluid control loop having a fluid supply line and a fluid return line plumbed to a respective fluid supply manifold and fluid return manifold on said molding machine;

a fixed displacement pump disposed in said control loop whereby temperature control fluid is volumetrically advanced from said fluid return line into said fluid supply line;

a servo motor by which said fixed displacement pump is driven; and

a control system by which said servo motor is controlled.

2. The fluid circulator system of claim 1, said control system comprising a computer-based control system.

3. The fluid circulator system of claim 1, further comprising a fluid temperature sensor connected to said control system.

4. The fluid circulator system of claim 1;

said circulator comprising;

means for changing the temperature of said temperature control fluid.

5. The fluid circulator system of claim 4, said fluid circulator system being a closed loop type circulator, said means for changing the temperature of said temperature control fluid comprising a heat exchanger, one side of which is disposed in said control loop, the other side of which is connected to a chiller system.

6. The fluid circulator system of claim 4, said fluid circulator system being a direct injection type circulator, said means for changing the temperature of said temperature control fluid comprising a direct injection valve disposed in said control loop and connected to a source of thermally conditioned make-up fluid.

7. The fluid circulator system of claim 4, said means for changing the temperature of said temperature control fluid comprising an in-line heater disposed in said control loop.

8. The fluid circulator system of claim 1, said servo motor being an electronic servo motor.

9. A fluid medium temperature control system for use in molding operations, comprising:

a fixed displacement pump disposed in a fluid circulation loop whereby a temperature control fluid is volumetrically advanced in said circulation loop, said circulation loop being configured with respect to a molding machine for transferring thermal energy between said temperature control fluid and said molding machine such that the temperature of said temperature control fluid is changed from a first temperature to a second temperature;

a servo motor by which said fixed displacement pump is driven;

a means for restoring the temperature of said temperature control fluid from said second temperature to said first temperature; and

a control system by which said servo motor is controlled.

10. The temperature control system of claim 9, said means for restoring the temperature from said second temperature to said first temperature comprising an evaporative cooling unit.

11. The temperature control system of claim 9, said means for restoring the temperature from said second temperature to said first temperature comprising a chiller.

12. The temperature control system of claim 9, said control system comprising a computer-based control system.

13. The temperature control system of claim 12, further comprising a fluid temperature sensor connected to said control system.

14. A method for controlling the temperature of a molding machine, comprising:

advancing a controlled volume of a temperature control fluid at a first temperature in a temperature control loop by means of a fixed displacement pump driven by a servo motor, said control loop being configured with respect to said molding machine for transferring thermal energy between said temperature control fluid and said molding machine based on the difference in said first temperature and the temperature of said molding machine, thereby changing said first temperature of said temperature control fluid to a second temperature.

15. The method for controlling the temperature according to claim 14, further comprising:

restoring the thermal energy level of said temperature control fluid such that said second temperature is restored to said first temperature.

16. The method for controlling the temperature according to claim 14, further comprising:

calculating said controlled volume based on said second temperature.

17. The method for controlling the temperature according to claim 16, further comprising:

monitoring said second temperature; and

advancing said controlled volume at a rate calculated from said second temperature to maintain a constant thermal energy level in said molding machine.

18. The method for controlling the temperature according to claim 14, further comprising:

displaying in real time on an operator interface the rate of said advancing of said temperature control fluid.

19. The method for controlling the temperature according to claim 18, further comprising:

displaying in real time on an operator interface said second temperature.

20. The method for controlling the temperature according to claim 18, further comprising:

displaying in real time on an operator interface said first temperature.

21. The method for controlling the temperature according to claim 18, further comprising:

displaying in real time on an operator interface the rate of delivery of said thermal energy from said molding machine to the control loop.