Fluid flow regulating systems

• US 4,174,065 A
• Filed: 11/21/1977
• Issued: 11/13/1979
• Est. Priority Date: 06/04/1976
• Status: Expired due to Term

• Current Assignee: Knauth Design Incorporated
• Original Assignee: Knauth Design Incorporated
• Inventors: Knauth, Berthold A.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US05/853,470
• Time in Patent Office: 722 Days
• Field of Search: 236/49, 236/DIG. 9, 236/35, 417/43, 417/423, 417/20, 417/32, 361/384, 62/186, 174/16 R, 73/228
• US Class Current: 236/49.1
• CPC Class Codes: G01F 1/28 by drag-force, e.g. vane type or impact flowmeter
• CPC Class Codes: G05D 23/1919 characterised by the type of controller
• CPC Class Codes: G05D 23/275 with sensing element expanding, contracting, or fusing in response to changes of temperature

Abstract

Fluid flow regulating systems involving systems for controlling the motor speed of fluid pumping devices are disclosed. The speed control systems involve use of a velocity head force sensor that movably responds to the velocity head forces of an air stream delivered by the pumping device, and these movements in the positions assumed by the force sensor are detected and used to control the power delivered to the motor. Temperature change detectors are used in most embodiments to modify the force sensor movements so as to introduce temperature change factors as well as velocity head force change factors into the control of the power circuitry. Force sensor of the pivotal vane, bendable vane and airfoil types are shown, and temperature sensors of the bimetallic and expandable fluid types are also used. A biasing force resistive of the velocity head forces is imparted to the force sensor to establish desired speed levels of operation and bimetallic temperature sensors are used in some embodiments to provide not only the biasing force, but also a variance in the biasing force which is responsive to the changes in temperatures and thus, to introduce the temperature change factors into the force sensor movements. Embodiments involving expandable temperature responsive fluids are shown and include a means for deflecting fluid flow from the force sensor so as to regulate the velocity head detected thereby, and as a means for introducing the temperature change factor into the force sensor movement.

Claims

1. A motor speed regulating system for an electrically powered motor that is drivingly connected to a fluid impeller comprising velocity head monitoring means having a force sensor that is mounted in a flow path for fluid delivered by the impeller for sensing the velocity head of the fluid flowing along the path, temperature sensing means for sensing the temperature of fluid delivered by the impeller, and circuit means connected to a power source and to the motor, said monitoring means being responsive to velocity head changes sensed by the force sensor, said temperature sensing means being responsive to temperature changes sensed thereby, and said circuit means operating under the control of said monitoring means and said temperature sensing means to regulate the power delivered to the motor in accord with the sensed fluid velocity head changes and temperature changes.

2. A motor speed regulating system in accord with claim 1 wherein the force sensor is movably deflectable from a null position by fluid velocity heads sensed thereby, wherein the monitoring means comprises means for detecting positions assumed by the force sensor and being responsive at the force sensor positions detected thereby to control said circuit means in accord with said fluid velocity head changes.

3. A motor speed regulating system in accord with claim 1 wherein the force sensor comprises a vane component which is pivotally deflectable from the null position by fluid velocity heads sensed thereby.

4. A motor speed regulating system in accord with claim 1 wherein the force sensor comprises a vane component which is resiliently deflectable from the null position by fluid velocity heads sensed thereby.

5. A motor speed regulating system in accord with claim 1 wherein the force sensor comprises an airfoil member having a cambered surface and being movably deflectable from the null position by fluid velocity heads sensed thereby.

6. A motor speed regulating system in accord with claim 2 wherein the deflectable movement of the force sensor from the null position is controlled by the temperature sensing means in accord with the temperature being sensed thereby, whereby the response of the position detecting means at the detected position assumed by the force sensor controls the circuit means in accord with said fluid velocity head changes and said temperature changes.

7. A motor speed regulating system in accord with claim 6 wherein the temperature sensing means is arranged to bias the force sensor toward its null position at the positions assumed by the force sensor in response to the velocity heads sensed thereby.

8. A motor speed regulating system in accord with claim 6 wherein the temperature sensing means and force sensor have common structure that includes bimetallic means resiliently deflectable in response to sensed fluid velocity head changes and bendable in response to sensed temperature changes.

9. A motor speed regulating system in accord with claim 6 wherein the temperature sensing means comprises bimetallic means establishing the null position of the force sensor.

10. A motor speed regulating system in accord with claim 9 wherein the bimetallic means is a resiliently deformable coiled bimetallic spring component.

11. A motor speed regulating system in accord with claim 6 comprising fluid flow deflecting means which is movable to regulate the flow of fluid along said path and which operates under the control of said temperature sensing means to increase and decrease the fluid flow along the path in response to respective decreasing and increasing temperature changes sensed by said temperature sensing means.

12. A motor speed regulating system in accord with claim 11 wherein said temperature sensing means comprises bellows means which is expandable and contractable in response to respective increasing and decreasing temperature changes for moving said deflecting means.

13. A motor speed regulating system in accord with claim 1 wherein said force sensor has a null position it assumes in the absence of flowing fluid along the path and is movably deflected in a downstream direction from the null position in response to a velocity head sensed thereby, and wherein the monitoring means comprises position detecting means for detecting positions assumed by the force sensor relative to the position detecting means, said position detecting means being responsive at force sensor positions detected thereby to control said circuit means in accord with said velocity head changes.

14. A motor speed regulating system in accord with claim 13 wherein said position detecting means is movable relative to the force sensor in response to the temperature changes sensed by the temperature sensing means, whereby the response of the position detecting means controls said circuit means in accord with said fluid velocity head changes and said temperature changes.

15. A motor speed regulating system in accord with claim 14 wherein the temperature sensing means comprises bimetallic means arranged to move said position detecting means in upstream and downstream directions in response to respective increasing and decreasing temperature changes detected by said temperature sensing means.

16. A motor speed regulating device for a forced air cooling system having a fan with an electrically powered motor, said device comprising a housing having airflow inlet and outlet openings for accomodating the flow of fan delivered air along a flow path through the housing, a force sensor that is mounted in the flow path for sensing the velocity head of the fluid flowing along the path, said force sensor having a null position it assumes in the absence of fan delivered airflow along the path and being movably deflectable from its null position in response to a velocity head sensed thereby, circuit means electrically connectable to the motor and a power source for regulating the power delivered to the motor, and control means for controlling the circuit means to increase and decrease the power delivered to the motor in response to force sensor movements reflecting respective decreasing and increasing changes in the velocity head sensed thereby, said device further comprising temperature sensing means for sensing the temperature of air delivered by the fan, and said control means being responsive to decreasing and increasing temperature changes sensed by the temperature sensing means to respectively decrease and increase the power delivered to the motor.

17. A motor speed regulating device in accord with claim 16 wherein said control means comprising light emitting means, and light detecting means for detecting light emitted by the light emitting means, said force sensor being arranged during its movements to interrupt emitted light detectable by the light detecting means, and said light detecting means being responsive to the light detected thereby to control the circuit means in accord with the changes in the velocity head sensed by the force sensor.

18. A motor speed regulating device in accord with claim 17 wherein said light emitting means is a gaseous discharge component.

19. A motor speed regulating device in accord with claim 17 wherein said light detecting means is a photocell.

20. A motor speed regulating device in accord with claim 16 wherein said force sensor is movably responsive to temperature changes sensed by the temperature sensing means.