US 6,581,847 B2 · Variable-air-volume diffuser, actuator assembly and method

Abstract

An adaptive control device (77) and method (102-108) for control of the operation of an actuator (72), and particularly thermally-powered actuator (72) of the type used in a variable-air-volume diffuser (71). The preferred adaptive control device is an expert system circuit which controls a heater (74) provided on a thermally-powered actuator (72) to implement an adaptive process (102-108) in which a sensed variable, such as room air temperature, is driven toward a target temperature control range (±0.25° F.). Most preferably, the process steps (106) include driving the room air temperature toward a gross (broader) temperature control range (±1.0° F.) by moving a diffuser damper assembly (80) to a substantially fully open or substantially fully closed position. Thereafter, and while inside the gross temperature control range, the process steps (107, 108) include adjustments to the position of the damper assembly (80) are made only when a sensed parameter, preferably the supply air flow rate, is in a stable condition. Most preferably, the damper (80) is temporarily “kicked” farther open or farther closed than necessary, to minimize hysteresis effects, and then adjusted to a posiiton which tends to drive the room air temperature into the narrower, targeted temperature control range.

Claims23

Dependent claims

A thermally powered actuator assembly comprising:

a thermally powered actuator having a movable element displaceable in response to temperature changes;
a heating assembly thermally coupled to said actuator in a position applying heat to said actuator to produce movement of said movable element;
a control device connected to said heating assembly and having an adaptive circuit formed for adaptive control of the operation of said heating assembly in response to input signals;
at least one sensor formed to sense a desired parameter and connected to said adaptive circuit for communication of input signals to said control device;
and
said control device being further formed to periodically sample input signals from said sensor and to adaptively modify operation of said heating assembly over time in response to the sampled input signals as to a parameter influenced by the actuator assembly.

3 more elements

A thermally powered actuator assembly comprising:

a thermally powered actuator having a movable element displaceable in response to temperature changes;
a heating assembly thermally coupled to said actuator in a position applying heat to said actuator to produce movement of said movable element;
a control device connected to said heating assembly and having an adaptive circuit formed for adaptive control of the operation of said heating assembly in response to input signals;
at least one sensor formed to sense a desired parameter and connected to said adaptive circuit for communication of input signals to said control device;
said control device being further formed to periodically sample input signals from said sensor and to adaptively modify operation of said heating assembly over time in response to the sampled input signals as to a parameter influenced by the actuator assembly;
and
said control device is formed to adaptively change said operation of said heating assembly based upon input signals from said sensor as to said parameter so as to accommodate at least one of:
a) hysteresis effects of said thermally powered actuator assembly;
b) speed of response of said thermally powered actuator assembly;
c) hysteresis effects of a mechanical driving assembly driven by said movable element;
d) ambient influences on said sensor assembly produced as a result of the location of said sensor assembly;
and
e) variations in the parameter being sensed by said sensor from a desired response of said parameter as influenced by said thermally powered actuator assembly;
and
f) ambient influences on said actuator.

12 more elements

Dependencies are inferred from the claim text.

Variable-air-volume diffuser, actuator assembly and method

Life of this patent

Variable-air-volume diffuser, actuator assembly and method

Life of this patent

Abstract

Claims23