Two-wire hot runner nozzle heater system
A hot runner nozzle heater system is provided with 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.
1. A hot runner nozzle heater system comprising:
at least one hot runner nozzle;
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;
two electrical lead wires connected to the resistive layer; and
a two-wire controller connected to the resistive layer through the two electrical lead wires, wherein the two-wire controller determines temperature of the heater system using the resistance of the resistive layer and controls heater system temperature accordingly through the two electrical lead wires, wherein the heater system provides heat to the at least one hot runner nozzle.
2. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises a DC bias control for calculation of the resistance of the resistive layer.
3. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises an AC bias control for calculation of the resistance of the resistive layer.
4. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises high conduction angle firing.
5. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises a shunt resistor for calculation of the resistance of the resistive layer.
6. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller further comprises a microprocessor.
7. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller further comprises firmware.
8. The hot runner nozzle heater system according to claim 1 , further comprising a protective layer disposed over the resistive layer.
9. The hot runner nozzle heater system according to claim 1 , wherein the resistive layer defines a pattern selected from the group consisting of spiral, rectangular, and circular.
10. The hot runner nozzle heater system according to claim 1 , wherein the resistive layer is formed by a method selected from a group consisting of thick film, thin film, thermal spray, and sol-gel.
11. The hot runner nozzle heater system according to claim 1 , further comprising a substrate disposed around the at least one hot runner nozzle, wherein the resistive layer is disposed over the substrate.
12. The hot runner nozzle heater system according to claim 1 , further comprising a dielectric layer disposed on an outer surface of the at least one hot runner nozzle, wherein the resistive layer is disposed on the dielectric layer.
13. 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 formed over the resistive layer;
two electrical lead wires connected to the resistive layer; and
a two-wire controller connected to the resistive layer through the two lead wires, wherein the two-wire controller determines temperature of the heater system using the resistance of the resistive layer and controls heater system temperature accordingly through the two electrical lead wires, wherein the heater system provides heat to the at least one hot runner nozzle.
14. A method of operating a layered heater in conjunction with a hot runner nozzle system comprising the steps of:
placing a substrate proximate a part to be heated;
supplying power to the layered heater through two electrical lead wires to a resistive layer of the layered heater;
transferring heat from the resistive layer, through a dielectric layer of the layered heater, and to the substrate; and
calculating the temperature of the resistive layer using a two-wire controller connected to the layered heater through the two electrical lead wires,
wherein the resistive layer is a heater element and a temperature sensor.
15. The method according to claim 14 , further comprising the step of resistance data calibration.
16. The method according to claim 14 , further comprising the step of lead wire calibration.
17. The method according to claim 14 , further comprising the step of temperature calibration.
18. The method according to claim 14 , further comprising the step of TCR calibration.