Air distribution system with flow limiting device

Claim 2

In an air distribution system wherein air at a Substantially constant temperature is delivered to a plurality of zones, the volume of said air delivered to each of said zones being normally varied according to the temperature of said zone, the improvement comprising means for sensing the velocity pressure and the static pressure of the air stream near said zone and transmitting said pressures to a pressure responsive means communicating with said sensing means, electrically operated switch means actuatable by said pressure responsive means to control the volume of air delivered to said zone regardless of zone temperature when the air flow rate as indicated by the relationship between said velocity pressure and said static pressure reaches a predetermined maximum.

Claim 3

In an air distribution system for delivering air at substantially constant temperature to a plurality of zones, the improvement including an air terminal unit for delivering air to one of said zones, said unit having movable damper means for varying the volume of air delivered to said zone, temperature responsive means to provide a signal to vary the position of said damper means in response to the temperature of said zone, sensing means in said unit to sense variations in the rate of air flow into said unit, said sensing means communicating with pressure responsive means movable in response to changes in said rate of air flow indicated by said sensing means, electrically operated switch means actuated in response to the movement of said pressure responsive means to override said temperature responsive means when said rate of air flow exceeds a predetermined maximum rate.

Claim 4

In an air distribution system for delivering air at substantially constant temperature to a plurality of zones, the improvement including an air terminal unit for delivering air to one of said zones, said unit having movable damper means for varying the volume of air delivered to said zone, temperature responsive means to provide a signal to vary the position of said damper means in response to the temperature of said zone, sensing means in said unit to sense variations in the rate of air flow into said unit, said sensing means communicating with pressure responsive means movable in response to changes in said rate of air flow indicated by said sensing means, electrically operated switch means actuated in response to the movement of said pressure responsive means to override said temperature responsive means when said rate of air flow exceeds a predetermined maximum rate.

Claim 5

The apparatus of claim 2 including at least one electric motor for moving said damper means.

Claim 6

The apparatus of claim 3 including a pair of electric motors, one of said motors adapted to move said damper means in a first direction and the other of said motors adapted to move said damper means in the direction opposite said first direction.

Claim 7

The apparatus according to claim 2 wherein said temperature responsive means is a bimetal thermostat.

Claim 8

The apparatus according to claim 2 wherein said sensing means comprises a pair of probes, one of said probes facing directly upstream of the air flow, and the other of said probes extending into the air stream and facing perpendicular to the direction of air flow.

Claim 9

The apparatus of claim 2 wherein said pressure responsive means includes an upper and lower chamber, said chambers being separated by a movable diaphram, lever means communicating with said diaphram movable in response to the movement of said diaphram, said lever means communicating with the terminals of said electrically operated switch means.

Claim 10

The apparatus of claim 7 including a spring member riding on said lever means to oppose upward movement of said lever means.

Claim 11

The apparatus of claim 7 wherein said diaphram and said lever means are movable upwardly in response to increasing air flow into said air terminal unit.

Claim 12

The apparatus according to claim 2 wherein said electrically operated switch is a snap-action switch.

Claim 13

In an air distribution system for delivering air at substantially constant temperature to a plurality of zones, the improvement comprising an air terminal unit for delivering air to one of said zones, said unit having movable damper means for varying the volume of air delivered to said zone, motor means operatively connected to said damper means to move said damper, temperature responsive means communicating with said motor means to provide a signal to said motor means to move said damper means in response to the temperature in said zone, sensing means in said unit to sense variations in the rate of air flow into said unit, said sensing means communicating with pressure responsive means movable in response to changes in said rate of air flow indicated by said sensing means, first switch means actuated by said pressure responsive means in response to an increase in air flow to discontinue movement of said damper means.

Claim 14

In an air distribution system for delivering air at substantially constant temperature to a plurality of zones, the improvement comprising an air terminal unit for delivering air to one of said zones, said unit having movable damper means for varying the volume of air delivered to said zone, motor means operatively connected to said damper means to move said damper, temperature responsive means communicating with said motor means to provide a signal to said motor means to move said damper means in response to the temperature in said zone, sensing means in said unit to sense variations in the rate of air flow into said unit, said sensing means communicating with pressure responsive means movable in response to changes in said rate of air flow indicated by said sensing means, first switch means actuated by said pressure responsive means in response to an increase in air flow to discontinue movement of said damper means.

Claim 15

ThE apparatus according to claim 11 further comprising second switch means actuated by said pressure responsive means in response to a further increase in air flow to move said damper means toward a closed position.