MINIMUM AIR VOLUME CONTROL DEVICE

• US 3,841,394 A
• Filed: 08/02/1973
• Issued: 10/15/1974
• Est. Priority Date: 08/02/1973
• Status: Expired due to Term

• Current Assignee: Robert M Van Becelaere
• Original Assignee: Robert M Van Becelaere
• Inventors: Van Becelaere, Robert M.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US05/385,187
• Time in Patent Office: 439 Days
• Field of Search: 236/49,1C,78C 137/625.28 318/467X 165/30
• US Class Current: 165/217
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: G05D 23/1925 using a combination of auxiliary electric and non-electric power
• CPC Class Codes: Y10T 137/86718 Dividing into parallel flow paths with recombining

Abstract

Apparatus and method for varying airflow in a variable air volume distribution system. A thermostat control normally acts to vary airflow to maintain constant temperature. In order to establish a minimum volume of airflow, a pressure differential member senses airflow volume and actuates an override switch to stop further decrease in or to increase the airflow when it drops to a predetermined minimum level.

Claims

1. In an air distribution system for delivering conditioned airflow at a preselected substantially constant temperature to a plurality of zones wherein the temperature at each of said zones is controlled by varying the volume of airflow to said zone;

an air throttling means for varying the volume of conditioned air delivered to said zone;

an electric motor operator coupled to said air throttling means to drive the latter in opposite directions to increase and decrease the volume of airflow;

a thermally responsive thermostat control switch disposed to sense temperature in said zone and connected with said motor operator for actuating the latter to vary airflow to maintain substantially constant temperature in said zone;

a first override control switch connected to said motor operator, said first override control switch effective when actuated to override said thermostat control switch and actuate said motor operator to stop further decrease in the volume of airflow to thereby establish a minimum volume of conditioned airflow delivered to said zone, said first override switch including means for sensing the volume of airflow to said zone and for actuating said first override switch whenever said volume of airflow drops to a predetermined minimum level;

an electrically controlled heat source in said zone; and

a second override control switch connected with said heat source and operable to activate said heat source upon being actuated by said airflow sensing means whenever said volume of airflow drops to a preselected level, said preselected level of airflow being greater than said predetermined minimum level.

2. An air distribution system as set forth in claim 1, wherein said second override control switch is connected with said motor operator and is effective when actuated to interrupt operation of said motor operator to prevent further decrease in volume of airflow delivered to said zone and to turn off said electrical heat source when said air flow drops to a preselected level.

3. In an air distribution system for delivering conditioned airflow at a preselected substantially constant temperature to a plurality of zones wherein the temperature at each of said zones is controlled by varying the volume of airflow to said zone;

an air throttling means for varying the volume of conditioned air delivered to said zone;

an electric motor operator coupled to said air throttling means to drive the latter in opposite directions to increase and decrease the volume of airflow;

a thermally responsive thermostat control switch disposed to sense temperature in said zone and connected with said motor operator for actuating the latter to vary airflow to maintain substantially constant temperature in said zone;

an override control switch connected to said motor operator, said override control switch effective when actuated to override said thermostat control switch and actuate said motor operator to stop further decrease in the volume of airflow to thereby establish a minimum volume of conditioned airflow delivered to said zone, said override switch including means for actuating said override switch whenever said volume of airflow drops to a predetermined minimum level; and

an electrically controlled heat source in said zone, said override switch being connected with said heat source to activate the latter when said airflow sensing means actuates said override switch to interrupt operation of said motor operator.

4. An air distribution system as set forth in claim 3, wherein is included a second override control switch and a second electrically controlled heat source in said zone connected with said second switch, said second override switch operable to activate said second heat source upon being actuated by said airflow sensing means whenever said volume of airflow drops to a preselected level, said preselected level of airflow being greater than said predetermined minimum level.