TECHNICAL FIELD

The present disclosure pertains generally to fire and smoke systems, and more particularly to fire and smoke systems using fire and smoke actuators that actuate dampers within supply and return air ducts of the fire and smoke system.

BACKGROUND

Fire and smoke systems are often used to regulate air flow within a building in the event of a fire and/or smoke event. In some cases, there may be a desire to provide fresh air from outside of the building in order to clear smoke from an interior of the building. In some cases, there may be a desire to reduce the flow of air into the building in order to starve a fire of oxygen. A fire and smoke system includes supply air ducts that bring fresh air directly into the building from outside of the building. A fire and smoke system also includes return air ducts that vent air from inside the building directly to the exterior of the building. These supply and return air ducts may be part of a Heating, Ventilation and Air Conditioning (HVAC) system, or may be separate from the HVAC system. The supply and return air ducts of the fire and smoke system include dampers within the air ducts in order to control relative air flow through the air ducts. The dampers can be actuated between a closed position in which air flow through a particular air duct is restricted and an open position in which air flow through the particular duct is not restricted or is less restricted. Dampers are driven between the closed position and the open position via actuators that employ a motor to drive an output that engages a damper shaft in order to move the damper in response to a control signal. Improvements in the hardware, user experience, and functionality of fire and smoke actuators, particularly at elevated operating temperatures, would be desirable.

SUMMARY

The disclosure is directed to fire and smoke actuators that are configured to adjust their operating speed in accordance with ambient temperatures. For example, at lower temperatures, such as may be experienced during the manufacturing process, and perhaps during installation, the fire and smoke actuators may operate at a relatively higher speed. At higher temperatures, such as may be experienced during a fire or smoke event. the fire and smoke actuators may operate at a relatively lower speed in order to protect the integrity of polymeric components within the actuator.

In a particular example of the disclosure, a fire and smoke actuator is configured to actuate a damper between an open position and a closed position. The fire and smoke actuator includes a temperature sensor for sensing an operating temperature of the fire and smoke actuator, a drive motor, an actuator output for coupling to the damper to move the damper between the open position and the closed position and a drivetrain that is operably coupled between the drive motor and the actuator output. When the drive motor is activated, the drive motor is to actuate the actuator output, via the drivetrain, to move the damper between the open position and the closed position. A drive circuit is operably coupled to the drive motor and the temperature sensor and is configured to activate the drive motor to move the damper between the open position and the closed position at a non-zero speed, wherein the non-zero speed is based, at least in part, on the operating temperature sensed by the temperature sensor.

In another example of the disclosure, a fire and smoke actuator that is configured to actuate a damper includes a motorized actuator for actuating the damper between a fully open position and a fully closed position, a temperature sensor and a controller that is operatively coupled to the motorized actuator and the temperature sensor. The controller is configured to operate the motorized actuator to move the damper between the fully open position and the fully closed position in less than 40 seconds when the temperature sensor indicates an operating temperature below a first temperature threshold and to operate the motorized actuator to move the damper between the fully open position and the fully closed position in a range of 50 to 75 seconds, as specified by regulatory standards, when the temperature sensor indicates an operating temperature above a second temperature threshold, wherein the first temperature threshold is less than or equal to the second temperature threshold.

In another example of the disclosure, a method of operating a fire and smoke actuator that is configured to actuate a damper includes measuring a temperature proximate the fire and smoke actuator. When the measured temperature is below a first temperature threshold, a drive motor of the fire and smoke actuator is operated at a first operating speed in order to open or close the damper. When the measured temperature is at or above a second temperature threshold, the drive motor of the fire and smoke actuator is operated at a second operating speed in order to open or close the damper, the second operating speed being less than the first operating speed.

The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify some of these embodiments.

