THERMAL SWITCH WITH SELF-TEST FEATURE

• US 20060208846A1
• Filed: 03/18/2005
• Published: 09/21/2006
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Davis, George D., Scott, Byron G.
• Granted Patent: US 7,358,740 B2
• Time in Patent Office: Days
• US Class Current: 337/333
• CPC Class Codes: H01H 2300/052 Controlling, signalling or testing correct functioning of a switch see also H01H2300/056 - H01H2300/066 and H01H11/0062
• CPC Class Codes: H01H 37/54 wherein the bimetallic element is inherently snap acting

Abstract

A normally open thermal switch (200) having a bimetallic disk (18) is configured for operational testing in its installed position when exposed to a changing temperature by a test box (400) having a power source (400a). The in-place testing advantageously confirms triggering action of the switch by an event indicator (400c) at the operational temperatures designed into the switch (200). The temperature of the triggering action is presented on a temperature display (400b) and recorded by a data recorder (400d) of the test box (400). The switch (200) incorporates a heating element (24c) to heat changing the bimetallic disk (18) to snap activate at the operative temperatures. The thermal switch (200) is coupled with the test box (400) to confirm its operation without having to remove the switch from its installed location.

Claims

1. A thermal switch testing system for detecting switch operation, comprising:

a housing;

a heating element disposed within the housing;

a switch device disposed within the housing;

a test box coupled with the switch device and the heating element, the test box comprising;

a heater component for causing the heating element to apply heat within the housing; and

a sensing component for sensing when the switch device toggles.

2. The system of claim 1, wherein the actuator is a bimetallic disk.

3. The system of claim 1, wherein the test box further includes an event indicator configured to indicate when the switch device toggles.

4. The system of claim 3, wherein toggling of the switch device includes at least one of going from a closed position to an open position or going from an open position to a closed position.

5. The system of claim 1, wherein the test box further comprises:

a component coupled to the heater component and the sensing component for determining a temperature within the housing at which the switch device toggled;

a display device for displaying the determined temperature.

6. The system of claim 5, wherein the test box further includes a storage device for storing the determined temperature.

7. The system of claim 1, wherein the thermal switch further comprises a temperature sensing element, wherein the test box further comprises:

a component coupled to the temperature sensing element and the sensing component for determining a temperature within the housing at which the switch device toggled;

a display for displaying the determined temperature.

8. The system of claim 7, wherein the test box further includes a storage device for storing the determined temperature.

9. The system of claim 1, wherein the test box is coupled to the thermal switch at a thermal switch installed position.

10. A thermal switch comprising:

a housing;

a thermal actuator located within the housing, the thermal actuator being coupled to a first pair of contacts having one end located external to the housing; and

a heater located within the housing, the heater coupled with a second pair of contacts having one end located external to the housing.

11. The switch of claim 10, wherein the thermal actuator includes a bimetallic disk.

12. A device comprising:

a housing;

a heater component disposed within the housing for causing a heating element within a thermal switch to apply heat within the thermal switch; and

a sensing component for sensing when a switch device of the thermal switch toggles.

13. The device of claim 12, wherein the test box is coupled to the thermal switch at a thermal switch installed position.

14. The device of claim 12, further comprising an event indicator configured to indicate when the switch device toggles.

15. The device of claim 12, further comprising:

a component coupled to the heater component and the sensing component for determining a temperature within the switch device at which the switch device toggled;

a display device for displaying the determined temperature.

16. The device of claim 15, further comprising a storage device for storing the determined temperature.

17. A method comprising:

coupling a test box to a thermal switch;

applying power to a heater within the thermal switch via the test box; and

determining temperature within the thermal switch at which the thermal switch toggles.

18. The method of claim 17, further comprises displaying the determined temperature.

19. The method of claim 17, further comprises storing the determined temperature.

20. The method of claim 17, wherein coupling includes coupling the test box to the thermal switch at an installed position of the thermal switch.