Parts washer with improved temperature and pump control

1. A parts washer for washing mechanical parts, said parts washer comprising, in combination, a parts receiving receptacle positionable on a reservoir for cleaning liquid, a drain opening formed in a part of said receptacle and a module engageable with a portion of the reservoir and the cleaning liquid for adjusting a temperature of the cleaning liquid and circulating the cleaning liquid into the parts receiving receptacle; the module including a heating element, a sensor assembly and a pump assembly including a pump and a motor for driving the pump, each of the heating element, sensor assembly and pump assembly are connected to and supported by a bracket, said bracket extending and depending from an enclosure housing a programmable temperature controller for receiving sensor assembly signals and generating heater element signals; the sensor assembly contiguous with the temperature controller such that the temperature controller displays the temperature of the cleaning liquid and a low liquid level condition; and a bridge thermally linking the heating element to a thermowell of the sensor assembly in which is disposed a thermocouple such that the sensor assembly normally generates a signal representing the temperature of cleaning liquid unless a level of the cleaning liquid is disposed below the sensor assembly.

2. The parts washer as defined in claim 1 , which further includes means under control of an operator for energizing the motor to drive the pump.

3. The parts washer as defined in claim 1 , wherein the module further includes a plate connected to the bracket for covering an opening defined between an upper edge of the reservoir and the adjacent parts receiving receptacle.

4. The parts washer as defined in claim 1 , wherein the pump assembly includes a housing, an inlet having a screen filter and an outlet fitting to which a tube is connected, the tube having a fitting connected to a distal end thereof, said fitting extending through and connected to a plate connected to the bracket for covering an opening defined between an upper edge of the reservoir and the parts receiving receptacle such that the pump assembly is independently disconnected from the module.

5. The parts washer as defined in claim 1 , wherein the bridge is contiguous with the thermowell and the heating element.

6. The parts washer as defined in claim 1 , wherein the temperature controller is a modular unit replaceable from an exterior of the enclosure.

7. The parts washer as defined in claim 1 , wherein the temperature controller includes an alpha-numeric array for displaying values representative of the temperature of the cleaning liquid, a temperature set-point and error codes.

8. The parts washer as defined in claim 1 , wherein the module further includes a surge suppressor and a resettable circuit interrupter.

9. The parts washer as defined in claim 1 , wherein the temperature controller includes a main control for maintaining the cleaning liquid temperature at a temperature set-point by receiving the sensor assembly signal, comparing the sensor assembly signal against the set-point, generating an activation signal if the sensor assembly signal is less than the set-point, and generating a deactivation signal if the sensor assembly signal is greater than the set-point, the main control is coupled to an interface control for generating a heating element signal responsive to the activation and deactivation signal for activating and deactivating the heating element.

10. The parts washer as defined in claim 1 , wherein the pump assembly includes a metal housing to which is attached support for connection with the bracket such that the pump assembly and support are modularly removable independent of the module.

11. The parts washer as defined in claim 1 , wherein the temperature controller is coupled to the heating element and selectively activates the heating element to maintain the temperature of the cleaning liquid within a preselected range.

12. A module for adjusting a temperature of a cleaning fluid in a reservoir of a parts washer and for circulating the cleaning liquid from the reservoir to a surmounted parts receiving receptacle, the module being removably received within the reservoir and cleaning liquid, said module comprising:

a heating element, a sensor assembly and a pump assembly, each connected to and supported by a bracket extending and depending from an enclosure;

the enclosure including a programmable temperature controller for receiving sensor assembly signals, generating heating element signals for periodically activating the heating element, wherein the sensor assembly is coupled to the temperature controller such that the temperature controller displays the temperature of the cleaning liquid and a low liquid level condition, a bridge thermally linking the heating element to a thermowell of the sensor assembly in which is disposed a thermocouple such that the sensor assembly normally generates a signal representing the temperature of the cleaning liquid unless a level of the cleaning liquid is disposed below the sensor assembly, and wherein the temperature controller periodically deactivates the heating element in order to prevent over-temperature of the cleaning liquid.

13. The module as defined in claim 12 , which further includes means under control of an operator for energizing a motor to drive a pump of the pump assembly.

14. The module as defined in claim 12 , wherein the module further includes a plate connected to the bracket for covering an opening defined between an upper edge of the reservoir and the parts receiving receptacle.

15. The module as defined in claim 12 , wherein the pump assembly includes a housing, an inlet having a screen filter and an outlet connected to a tube which has a fitting connected to a distal end thereof, said fitting extending through and connected to a plate connected to the bracket for covering an opening defined between an upper edge of the reservoir and the parts receiving receptacle such that the pump assembly is independently quickly disconnected from the module.

16. The module as defined in claim 12 , wherein the bridge is contiguous with the thermowell and the heating element.

17. The module as defined in claim 12 , wherein the temperature controller includes an alpha-numeric array for displaying values representative of the temperature of the cleaning liquid, a temperature set-point and error codes.

18. The module as defined in claim 12 , wherein the temperature controller, includes a processing unit and memory that stores programming instructions, that, when read by the processing unit, cause the controller to function to:

(i) receive a set-point for a desired cleaning liquid temperature;

(ii) activate the heating element periodically;

(iii) monitor the temperature of the cleaning liquid continuously;

(iv) compare the monitored temperature of the cleaning liquid against the set-point;

(v) alter the periodic activation of the heating element such that the temperature of the cleaning liquid is moved toward the set-point; and

(vi) repeat (ii)-(vi).

19. The module as defined in claim 18 , including further programming instructions, that, when read by the processing unit, causes the controller to function to:

(i) generate an error code in response to an over-temperature condition; and

(ii) deactivate the heating element in order to correct the over-temperature condition.

20. The module as defined in claim 18 , wherein the set-point is defined as an operating range having an upper limit and a lower limit to which the temperature of the cleaning liquid is compared.

21. The module as defined in claim 12 , wherein the enclosure further includes a main power switch, a circuit interrupter, a circuit interrupter reset button disposed on a movable cover and a surge suppressor.

22. The module as defined in claim 12 , wherein the enclosure further includes a handle for lifting the module disposed adjacent a top edge thereof and a spacer for aligning the enclosure with respect to the reservoir disposed adjacent a bottom edge thereof.

23. The module as defined in claim 12 , wherein the temperature controller is a modular unit replaceable from an exterior of the enclosure.

24. The module as defined in claim 12 , wherein the temperature controller includes a main control for maintaining the cleaning temperature at a temperature set-point by receiving the sensor assembly signal, comparing the sensor assembly signal against the set-point, generating an activation signal if the sensor assembly signal is less than the set-point, and generating a deactivation signal if the sensor assembly signal is greater than the set-point, the main control is coupled to an interface control for generating a heater element signal responsive to the activation and deactivation signal for activating and deactivating the heating element.

25. In a parts washer including a receptacle positionable on a container forming a cleaning liquid reservoir, a drain opening in said receptacle, and a module including a pump and motor secured thereto, said pump including an inlet and an outlet and a tube extending between said outlet and an interior portion of said receptacle, whereby activation of said motor turns said pump to pick up the cleaning liquid and circulate the cleaning liquid through said tube to the interior portion of said parts receiving receptacle through said drain opening and into said reservoir, the improvement comprising the module including a programmable temperature controller coupled to a sensor assembly and a heating element, wherein the sensor assembly includes a bridge thermally linking a temperature sensor and the heating element, wherein the sensor assembly includes a bridge thermally linking a temperature sensor and the heating element, and wherein a desired set-point is inputted to the temperature controller such that periodic activation and deactivation of the heating element in cooperation with the sensor assembly results in the cleaning liquid disposed at a temperature with in one degree Fahrenheit of the desired set-point.

26. The parts washer as defined in claim 25 , wherein the temperature controller is a modular unit replaceable from an exterior of the enclosure.

27. The parts washer as defined in claim 25 , wherein a thermocouple of the sensor assembly disposed within a thermowell and the thermowell is disposed closely proximate to the heating element.