Two-wire layered heater system

• US 20050109767A1
• Filed: 11/21/2003
• Published: 05/26/2005
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: Watlow Electric Manufacturing Company
• Original Assignee: Watlow Electric Manufacturing Company
• Inventors: Steinhauser, Louis P., Ptasienski, Kevin, McDowell, William A. III, Fennewald, Kenneth F.
• Granted Patent: US 7,196,295 B2
• Time in Patent Office: Days
• US Class Current: 219/543
• CPC Class Codes: B29C 2045/274 Thermocouples or heat sensors
• CPC Class Codes: B29C 2045/2745 Film-like electrical heaters
• CPC Class Codes: B29C 45/2737 Heating or cooling means therefor B29C45/7331 takes precedence
• CPC Class Codes: H05B 1/023 Industrial applications
• CPC Class Codes: H05B 2203/002 Heaters using a particular layout for the resistive material or resistive elements
• CPC Class Codes: H05B 2203/011 Heaters using laterally extending conductive material as connecting means
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 2203/035 Electrical circuits used in resistive heating apparatus
• CPC Class Codes: H05B 3/26 heating conductor mounted on insulating base for transparent areas H05B3/84, H05B3/86
• CPC Class Codes: H05B 3/28 heating conductor embedded in insulating material
• CPC Class Codes: H05B 3/42 non-flexible
• CPC Class Codes: H05B 3/46 heating conductor mounted on insulating base

Abstract

A heater system is provided that comprises a layered heater in communication with a two-wire controller, wherein a resistive layer of the layered heater is both a heater element and a temperature sensor. The two-wire controller thus determines temperature of the layered heater using the resistance of the resistive layer and controls heater temperature through a power source. Furthermore, a heater system using a layered heater in communication with a two-wire controller for a specific application of a hot runner nozzle in an injection molding system is provided by the present invention.

Claims

1. A heater system comprising:

a thick film heater defining;

a substrate;

a dielectric layer disposed on the substrate;

a resistive layer disposed on the dielectric layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a protective layer disposed over the resistive layer; and

a two-wire controller in communication with the thick film heater, wherein the two-wire controller determines temperature of the thick film heater using the resistance of the resistive layer and controls heater temperature accordingly.

2. A heater system comprising:

a thick film heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the thick film heater using the resistance of the resistive layer and controls heater temperature accordingly.

3. A heater system comprising:

a thin film heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the thin film heater using the resistance of the resistive layer and controls heater temperature accordingly.

4. A heater system comprising:

a thermally sprayed heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the thermally sprayed heater using the resistance of the resistive layer and controls heater temperature accordingly.

5. A heater system comprising:

a sol-gel heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the sol-gel heater using the resistance of the resistive layer and controls heater temperature accordingly.

6. A heater system comprising:

a layered heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the layered heater using the resistance of the resistive layer and controls heater temperature accordingly.

7. The heater system according to claim 6, wherein the two-wire controller comprises a DC bias control for calculation of the resistance of the resistive layer.

8. The heater system according to claim 6, wherein the two-wire controller comprises an AC bias control for calculation of the resistance of the resistive layer.

9. The heater system according to claim 6, wherein the two-wire controller comprises high conduction angle firing.

10. The heater system according to claim 6, wherein the two-wire controller comprises a shunt resistor for calculation of the resistance of the resistive layer.

11. The heater system according to claim 6, wherein the two-wire controller further comprises a microprocessor.

12. The heater system according to claim 6, wherein the resistive layer defines a pattern selected from the group consisting of spiral, rectangular, and circular.

13. The heater system according to claim 6, wherein the two-wire controller further comprises firmware.

14. A heater system comprising:

a thick film heater defining;

a dielectric layer;

a resistive layer disposed on the dielectric layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a protective layer disposed over the resistive layer; and

a two-wire controller in communication with the thick film heater, wherein the two-wire controller determines temperature of the thick film heater using the resistance of the resistive layer and controls heater temperature accordingly.

15. A hot runner nozzle heater system comprising:

at least one hot runner nozzle;

a substrate disposed proximate the hot runner nozzle;

a dielectric layer disposed on the substrate;

a resistive layer disposed on the dielectric layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor;

a protective layer disposed over the resistive layer; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the heater system using the resistance of the resistive layer and controls heater system temperature accordingly.

16. A hot runner nozzle heater system comprising:

at least one hot runner nozzle; and

at least one resistive layer disposed proximate the runner nozzle, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

a two-wire controller connected to the resistive layer, wherein the two-wire controller determines temperature of the heater system using the resistance of the resistive layer and controls heater system temperature accordingly.

17. A heater system for use with an existing temperature controller having at least one temperature sensor input and a power output, the improvement comprising:

at least one layered heater, the layered heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor; and

at least one two-wire module connected to the layered heater and to the temperature controller,

wherein the two-wire module determines temperature of the layered heater using the resistance of the resistive layer and transmits the temperature of the layered heater to the temperature controller input, and the temperature controller transmits the power output to the two-wire module.

18. A heater system comprising:

a layered heater comprising at least one resistive layer, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor;

an electrical lead connected to the resistive layer;

a controller connected to the resistive layer through the electrical lead, wherein the controller determines temperature of the layered heater using the resistance of the resistive layer and controls heater temperature accordingly;

a common return device connected to the layered heater; and

a power source connected to the controller,

wherein the common return device provides an electrical return to the controller from the layered heater.

19. A method of operating a layered heater comprising the steps of:

supplying power to the layered heater through a set of electrical leads to a resistive layer of the layered heater; and

calculating the temperature of the resistive layer using a two-wire controller connected to the layered heater through the set of electrical leads, wherein the resistive layer is a heater element and a temperature sensor.

20. The method according to claim 19, further comprising the step of resistance data calibration.

21. The method according to claim 19, further comprising the step of lead wire calibration.

22. The method according to claim 19, further comprising the step of temperature calibration.

23. The method according to claim 19, further comprising the step of TCR calibration.

24. A method of operating a layered heater in conjunction with a hot runner nozzle system comprising the steps of:

supplying power to the layered heater through a set of electrical leads to a resistive layer of the layered heater; and

calculating the temperature of the resistive layer using a two-wire controller connected to the layered heater through the set of electrical leads, wherein the resistive layer is a heater element and a temperature sensor.