Anti-entrapment and anti-dead head function

• US 8,602,745 B2
• Filed: 12/11/2006
• Issued: 12/10/2013
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: Danfoss Power Electronics A/S (Danfoss A/S), Pentair Water Pool And Spa Incorporated (Pentair Plc (Ireland))
• Original Assignee: Danfoss Low Power Drives, Pentair Water Pool And Spa Incorporated (Pentair Plc (Ireland))
• Inventors: Stiles, Robert W. Jr., Berthelsen, Lars Hoffmann, Westermann-Rasmussen, Peter, Kjaer, Gert, Lungeanu, Florin
• Primary Examiner(s): Kramer, Devon
• Assistant Examiner(s): BAYOU, AMENE SETEGNE
• Application Number:
  US11/609,057
• Publication Number:
  US 20070183902A1
• Time in Patent Office: 2,556 Days
• Field of Search: 417/44.1, 417/44.11, 417/42, 417/53, 417/63
• US Class Current: 417/44.11
• CPC Class Codes: F04B 49/20 by changing the driving speed
• CPC Class Codes: F04D 13/06 the pump being electrically driven
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0077 Safety measures F04D15/02 takes precedence
• CPC Class Codes: F04D 15/0088 Testing machines
• CPC Class Codes: F04D 15/0254 the condition being speed or load
• CPC Class Codes: F05D 2270/335 Output power or torque

Abstract

Embodiments of the invention provide a system including a pump, a motor, and a controller. The controller establishes a baseline value of power consumption during a deadhead condition, increases a counter when a current value decreases below the baseline value, and determines a deadhead condition when the counter exceeds a limit. The controller also compares a current value to an immediately previous power consumption value to determine an entrapment condition indicated by a sudden decrease in power consumption.

Claims

1. A pumping system for at least one aquatic application, the pumping system comprising:

a pump;

a motor coupled to the pump; and

a controller in communication with the motor,

the controller establishing a baseline value of power consumption of the motor during a deadhead condition,

the controller determining a current value of power consumption of the motor,

the controller increasing a counter when the current value decreases below the baseline value, and

the controller determining a deadhead condition caused by a blockage downstream from the pump when the counter exceeds a limit.

2. The pumping system of claim 1, wherein the baseline value is a percentage of a no flow power value, the no flow power value representing power consumed during a substantially complete blockage of downstream plumbing.

3. The pumping system of claim 2, wherein the no flow power value is dependent on a current speed of the motor.

4. The pumping system of claim 1, wherein the baseline value depends on user inputs related to a sensitivity of the pumping system, the user inputs being provided through a user interface.

5. The pumping system of claim 1, wherein a decrease in power consumption of the motor is indicated by at least one of a relative amount of decrease, a comparison of decreased values, time elapsed since a decrease, and a number of consecutive decreases.

6. The pumping system of claim 1, wherein a decrease in power consumption of the motor is based on a measurement of at least one of current and voltage provided to the motor.

7. The pumping system of claim 1, wherein a decrease in power consumption of the motor is based on at least one of a power factor, a resistance, and a friction of the motor.

8. The pumping system of claim 1, wherein a decrease in power consumption of the motor is based on a temperature of water in the aquatic application.

9. The pumping system of claim 1, wherein the controller determines a current value of power consumption of the motor based on an input power to the motor.

10. The pumping system of claim 1, wherein the controller monitors at least one of a power error determination, a current motor speed compared to at least one of a maximum speed and a minimum speed, a current motor speed compared to a previous motor speed, and a speed change input received from a user interface.

11. The pumping system of claim 1, wherein the controller monitors at least one of a separate controller, a manual control system, and a separate program running within the controller providing at least one of a motor speed, power consumption of the motor, a flow rate, and a pressure.

12. The pumping system of claim 1, wherein when the controller determines a deadhead condition, the controller at least one of stops the motor, varies a speed of the motor, displays a visual indication, locks out the motor until a specific action occurs by a user, and automatically restarts the motor.

13. The pumping system of claim 12, wherein a time delay occurs before automatically restarting the motor.

14. The pumping system of claim 12, wherein the controller does not automatically restart the motor if the pumping system remains blocked after at least one failed restart attempt.

15. A pumping system for at least one aquatic application, the pumping system comprising:

a pump;

a motor coupled to the pump; and

a controller in communication with the motor,

the controller comparing a current power consumption value of the motor to a substantially immediately previous power consumption value of the motor to determine a difference value,

the controller shutting down the motor substantially immediately if the difference value indicates a sudden decrease in power consumption of the motor occurring during an entrapment condition caused by a blockage on a suction side of the pump,

the controller performing a condition check to determine whether a speed of the motor has recently changed before shutting down the motor in order to avoid shutting down the motor due to torque ripple,

wherein if the speed has recently changed, the controller calculates a power gradient baseline value based on the change in speed and corresponding oscillations in power consumption of the motor.

16. The pumping system of claim 15, wherein the power gradient baseline value includes a trigger level capable of preventing erroneous triggering of an entrapment condition during speed change transition and setting times, while permitting an entrapment condition in the event of a severe power gradient change.

17. A pumping system for at least one aquatic application, the pumping system comprising:

a pump;

a motor coupled to the pump; and

a controller in communication with the motor,

the controller comparing a current power consumption value of the motor to a substantially immediately previous power consumption value of the motor to determine a difference value,

the controller shutting down the motor substantially immediately if the difference value indicates a sudden decrease in power consumption of the motor occurring during an entrapment condition caused by a blockage on a suction side of the pump,

the controller performing a condition check to determine whether a speed of the motor has recently changed before shutting down the motor in order to avoid shutting down the motor due to torque ripple,

wherein if the speed has not recently changed, the controller calculates a power gradient baseline value based on a percentage of a present power consumption of the motor.

18. The pumping system of claim 17, wherein an entrapment condition is triggered if a present change in power consumption of the motor exceeds the percentage of the present power consumption.