Ventilation system for modular electronic housing

• US 4,817,865 A
• Filed: 03/17/1988
• Issued: 04/04/1989
• Est. Priority Date: 03/17/1988
• Status: Expired due to Fees

• Current Assignee: Racal-Datacom, Inc. (Thales SA)
• Original Assignee: Racal Data Communications Incorporated
• Inventors: Wray, Donald L.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/169,551
• Time in Patent Office: 383 Days
• Field of Search: 236/49 D, 236/DIG. 9, 165/22, 361/384, 361/382, 361/379
• US Class Current: 236/49.3
• CPC Class Codes: H05K 7/207 Thermal management, e.g. cabinet temperature control

Abstract

A ventilation arrangement for a modular enclosure for electronic circuits includes a ventilation fan (8) including a motor (10) for providing movement of cooling air in the modular enclosure, the motor (10) being operable at at least two speeds including a lower speed and a higher speed wherein the higher speed induces greater air movement than the lower speed. A plurality of modular compartments (1, 2, 3, 4, 5) house a corresponding plurality of electronic circuits, with each of the modular compartments including an air path for the cooling air moved by the ventilation fan (8). A plurality of temperature sensors (32, 34, 36, 38, 40), one situated in each of the modular compartments (1, 2, 3, 4, 5), individually sense the temperature in each of the compartments. A speed control circuit (66), responsive to each of the temperature sensors causes the motor (10) to operate at the lower speed if the temperature in each of the modular compartments is below a predetermined threshold and causes the motor (10) to operate at the higher speed if the temperature in any one or more of the modular compartments exceeds the predetermined threshold. In this manner, if any of the modular compartments requires additional ventilation, the speed of operation of the motor (10) is increased to provide the required additional ventilation.

Claims

1. A ventilation arrangement for a modular enclosure for electronic circuits, comprising in combination:

a ventilation fan includng a motor for providing movement of cooing air in said modular enclosure, said motor being operable at at least two speeds including a lower speed and a higher speed wherein said higher speed induces greater air movement than said lower speed;

a plurality of modular electronic circuit compartments for housing a corresponding plurality of electronic circuits, each of said modular compartments including an air path for said cooling air moved by said ventilation fan;

a plurality of temperature sensing means, one situated in each of said modular compartments, for individually sensing the temperature in each of said compartments as an indication of the temperature of each of said electronic circuits; and

speed control means, responsive to each of said temperature sensing means, for causing said motor to operate at said lower speed if the temperature in each of said modular compartments is below a predetermined threshold and for causing said motor to operate at said higher speed if the temperature in any one or more of said modular compartments exceeds said predetermined threshold;

whereby, if any one or more of said electronic circuits within said modular compartments require additional ventilation, the speed of operation of said motor is increased to provide the required additional ventilation in all of said compartments.

2. The apparatus of claim 1, wherein said sensing means includes means for converting a temperature to a D. C. voltage.

3. The apparatus of claim 2, wherein said sensing means further includes comparing means for comparing said D. C. voltage to a reference voltage in order to determine whether or not the temperature has exceed said predetermined threshold.

4. The apparatus of claim 3, wherein said comparing means includes a plurality of open collector output comparitors, each of which have their outputs tied together to a common node.

5. The apparatus of claim 1, further comprising a source of a plurality of D. C. voltages and switching means for switching said plurality of D. C. voltages to said motor in order to establish said higher and said lower speeds.

6. A ventilation arrangement for a modular enclosure for electronic circuits, comprising in combination:

a ventilation fan including a motor for providing movement of cooing air in said modular enclosure, said motor being operable at at least two speeds including a lower speed and a higher speed wherein said higher speed induces greater air movement than said lower speed;

a plurality of modular electronic circuit compartments for housing a corresponding plurality of electronic circuits, each of said modular compartments including an air path for said cooling air moved by said ventilation fan;

a plurality of temperature sensing means, one situated in each of said modular compartments, for individually sensing the temperature in each of said compartments as an indication of the temperature of each of said electronic circuits, said sensing means including means for converting a temperature to a D. C. voltage;

comparing means for comparing said D. C. voltage to a reference voltage in order to determine whether or not the temperature has exceed said predetermined threshold, said comparing means including a plurality of open collector output comparitors, each of which have their outputs tied together to a common node;

a source of a plurality of D. C. voltages;

speed control means, responsive to said comparing means, for causing said motor to operate at said lower speed if the temperature in each of said modular compartments is below a predetermined threshold, and for causing said motor to operate at said higher speed if the temperature in any one or more of said electronic circuits within said modular compartments exceeds said predetermined threshold so that increased air movement is provided, said speed control means including switching means for switching said plurality of D. C. voltages to said motor in order to cause said motor to operate at said higher and said lower speeds.

7. A method of controlling the speed of a ventilation fan motor used to cool electronic circuits within a modular electronic housing, said modular electronic housing having a plurality of modular electronic circuit compartments, comprising the steps of:

sensing a temperature in each of said plurality of modular compartments as an indication of the temperature of each of said electric circuits;

comparing each of said sensed temperatures with a temperature threshold; and

increasing an operating speed of a ventilation fan so that cooling air flow is increased in each of said plurality of compartments in the event one or more of said sensed temperatures exceeds said predetermined thresholds.

8. The method of claim 7, wherein said sensing step is carried out by converting said sensed temperature to a signal level and said comparing step is carried out by comparing said signal level with a reference signal level.

9. The method of claim 7, wherein said increasing step is carried out by increasing a voltage to a motor driving said ventilation fan.

10. The method of claim 7, wherein said comparing step includes driving a single signal line by a plurality of open collector output comparitors.