Multitemperature responsive coolant coil fan control and method

• US 5,228,307 A
• Filed: 07/22/1992
• Issued: 07/20/1993
• Est. Priority Date: 02/27/1991
• Status: Expired due to Fees

• Current Assignee: Kobatecon Group, Inc.
• Original Assignee: Kobatecon Group, Inc.
• Inventors: Koce, Joseph J.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/918,283
• Time in Patent Office: 363 Days
• Field of Search: 62/180, 62/182, 62/186, 62/231, 62/158, 62/157, 236/11, 236/9 A, 236/DIG. 9, 165/39, 165/40
• US Class Current: 62/186
• CPC Class Codes: F24F 11/83 by controlling the supply of heat-exchange fluids to heat-exchangers
• CPC Class Codes: F25D 17/067 Evaporator fan units
• CPC Class Codes: G05D 23/1931 to control the temperature of one space
• CPC Class Codes: Y10S 236/09 Fan control

Abstract

A cooling system (10) with a control temperature sensor (24) for sensing the temperature of a coolant coil (14) for control of a coolant coil fan (18) in cooperation with ambient temperature sensed by a thermostat (30) to obtain optimum utilization of residual cooling power of the coolant coil (14) after the condenser (28) has been deactivated and to protect against overcooling and consequent icing of the coolant coil (14) in the event of inadvertent failure of the thermostat (30) to turn off the condenser(28).

Claims

1. In an air cooling system having a coolant coil and a coolant coil fan, the improvement being a multitemperature responsive control system, comprising:

means for sensing the ambient temperature;

means for sensing a nonambient control temperature related to the temperature of the coolant coil; and

means responsive to both the ambient temperature sensing means and the control temperature sensing means for controlling the coolant coil fan including means for activating to the nonambient control temperature sensing means for activating the coolant coil fan independently of the ambient temperature sensing means.

2. The air cooling system of claim 1 in which said coolant coil fan controlling means includes

means responsive to the control temperature sensing means for deactivating the coolant coil fan, and

means responsive to the ambient temperature sensing means for activating the coolant coil fan.

3. The air cooling system of claim 2 in which

the responsive means to the ambient temperature sensing means for activating the coolant coil fan includes a thermostat switch of an ambient thermostat responsive to said ambient temperature sensing means,

the responsive means to the control temperature sensing means for deactivating the coolant coil fan includes an override switch responsive to the control temperature, and

said coolant coil fan controlling means also includes means for interconnecting said switches between a means of electrical power and the coolant coil fan.

4. The air cooling system of claim 3 in which said override switch has an override pole and an nonoverride pole responsively associated with an override state in which power need be applied only through the override switch alone to activate the coolant coil fan and a nonoverride position in which power must be applied through both the thermostat switch and the override switch to actuate the coolant coil fan.

5. The air cooling system of claim 2 in which said means responsive to the control temperature sensing means for deactivating the coolant coil fan includes

means for applying power to the coolant coil fan independently of the responsive means for the ambient temperature sensing means for activating the coolant coil fan in response to the control temperature decreasing below a preselected temperature, and

means for applying power to the coolant coil fan through the responsive means to the ambient temperature sensing means for activating the coolant coil fan in response to the control temperature increasing above a preselected temperature.

6. The air cooling system of claim 2 in which said responsive means to the ambient temperature sensing means for activating the coolant coil fan includes

means for applying power to the coolant coil fan when the ambient temperature exceeds a preselected ambient set temperature, and

means for removing power to the coolant coil fan when the ambient temperature decreases below a preselected ambient temperature and the control temperature increases above a preselected control set temperature.

7. The air cooling system of claim 2 in which said deactivating means includes means for overriding the removal of power from the coolant coil fan by the activating means until the control temperature has exceeded a preselected control set temperature.

8. The air cooling system of claim 1 in which said control temperature sensor detects temperature at a location adjacent the coolant coil.

9. The air cooling system of claim 8 in which said control temperature sensor is a bimetallic switch with two poles respectively associated with an override state and a nonoverride state.

10. The air cooling system of claim 8 in which the control temperature sensor detects temperature upstream of the coolant coil.

11. A coolant temperature responsive override control unit for an air cooling system having an ambient thermostat for control of a condenser and of a coolant coil fan, comprising:

means for sensing the temperature of the coolant coil;

means responsive to the coolant coil sensing means for activating the coolant coil fan independently of the ambient thermostat;

an ambient thermostat for activating the condenser and the coolant coil fan independently of the coolant coil temperature sensing means; and

means responsive to the coolant coil temperature sensing means for disabling the ambient thermostat from deactivating the coolant coil fan after the ambient thermostat has activated the coolant coil fan.

12. The override control unit of claim 11 in which said disabling means includes means for applying power to the coolant coil fan independently of the thermostat.

13. The override control unit of claim 12 in which said disabling means is a switch with a housing mountable to a conduit of the cooling system with the temperature sensing means mounted to said housing and extending therefrom for mounting within the conduit.

14. The override control of claim 13 in which said temperature sensing means comprises a bimetal element responsive to temperature changes for mechanically activating the switch between an override position in which power is independently applied to the coolant coil fan and a nonoverride position.

15. A method of controlling a coolant coil fan of a cooling system with an ambient temperature sensing thermostat and a compressor, comprising the steps of:

sensing a nonambient control temperature related to the temperature of the coolant coil below a pre-select set temperature at a location apart from the ambient temperature thermostat; and

activating the coolant coil fan independently of the ambient temperature sensing thermostat in response to the nonambient control temperature decreasing below the preselected nonambient set temperature until the nonambient control temperature increases above the preselected control set temperature.

16. The method of claim 15 includes the step of applying power to the coolant coil fan independently of the thermostat in response to the nonambient control temperature decreasing below a preselected control set temperature.

17. The method of claim 16 which includes the step of enabling the ambient thermostat to remove power from the coolant coil fan in response to the control temperature increasing above a preselected control set temperature.

18. The method of claim 15 including the step of removing power from the coolant coil fan in response to the control temperature moving above a preselected control set temperature.

19. The method of claim 15 including the steps of

mounting a temperature sensing means at a location to sense the temperature within a conduit of the system adjacent the coolant coil, and

connecting the temperature sensing means to an override switch located without the conduit for connection between the thermostat switch and the coolant coil fan.

20. The method of claim 15 including the step of initiating the reapplication of power to the coolant fan by the ambient thermostat in response to the control temperature exceeding a preselected control set temperature.