Reduced-energy-consumption latching actuator

• US 6,450,478 B2
• Filed: 08/07/2001
• Issued: 09/17/2002
• Est. Priority Date: 10/21/1999
• Status: Expired due to Term

• Current Assignee: Arichell Technologies Inc. (Sloan Valve Company)
• Original Assignee: Arichell Technologies Inc. (Sloan Valve Company)
• Inventors: Mo, Xiaoxiong, Parsons, Natan E.
• Primary Examiner(s): RIVELL, JOHN A
• Application Number:
  US09/924,130
• Publication Number:
  US 20010048086A1
• Time in Patent Office: 406 Days
• Field of Search: 251/129.04, 251/65, 361/160, 361/154, 137/624.11
• US Class Current: 251/129.04
• CPC Class Codes: F16K 31/0675 Electromagnet aspects, e.g. electric supply therefor
• CPC Class Codes: F16K 31/082 using a electromagnet and a permanent magnet

Abstract

A latching-valve system (10) includes a piezoelectric transducer (44) mounted on its housing (16). To change the valve'"'"'s state, a microcontroller (54) causes a valve driver (58) to drive current through the actuator'"'"'s coil (12). It continues driving current through the coil (12) until the transducer'"'"'s output reaches a magnitude characteristic of the disturbance that typically results when the actuator'"'"'s armature (22) reaches the end of its travel. At that point, the microcontroller (54) stops driving current through the coil. If the characteristic sound does not occur within a predetermined duration, the microcontroller (54) causes a voltage-multiplier circuit (Q1, L1, D1) to increase the voltage that the valve driver (58) applies to the coil.

Claims

1. An actuator system comprising:

A) a latching actuator including an armature and a coil operable by application of a coil drive thereto in a first drive direction to conduct current in a first current direction and thereby tend to drive the armature to a first end position;

B) an endpoint detector that detects the armature'"'"'s reaching the first end position and responds thereto by generating a detector output indicative thereof; and

C) a control circuit operable to begin application of coil drive to the coil in the first direction at a normal first-direction drive level and, if the detector output has not indicated within a predetermined first drive duration thereafter that the armature has reached the first end position, to apply coil drive to the coil in the first direction at an elevated first-direction drive level higher than the normal first-direction drive level.

2. An actuator system as defined in claim 1 wherein:

A) the coil is operable by application of a coil drive thereto in a second drive direction to conduct current in a second current direction and thereby tend to drive the armature to a second end position;

B) the endpoint detector responds to the armature'"'"'s reaching the second end position by generating a detector output indicative thereof; and

C) the control circuit is operable to begin application of coil drive to the coil in the second direction at a normal second-direction drive level and, if the detector output has not indicated within a predetermined second drive duration thereafter that the armature has reached the second end position, to apply coil drive to the coil in the second direction at an elevated second-direction drive level higher than the normal second-direction drive level.

3. An actuator system as defined in claim 2 wherein the first and second drive durations are the same.

4. An actuator system as defined in claim 2 wherein:

A) the endpoint detector includes a sound sensor that is so coupled to the actuator as to sense sound made by the armature in reaching the first and second end positions and generates a sensor output indicative of the sound that it senses;

B) the detector output indicates that the armature has reached the first end position if the sensor output meets a predetermined first current-termination criterion; and

C) the detector output indicates that the armature has reached the second end position if the sensor output meets a predetermined second current-termination criterion.

5. An actuator system as defined in claim 4 wherein the sound sensor includes a piezoelectric transducer.

6. An actuator system as defined in claim 1 wherein the control circuit stops applying the coil drive in the first direction after the predetermined normal first-direction drive duration before driving the coil at the higher level.

7. An actuator system as defined in claim 6 wherein:

A) the coil is operable by application of a coil drive thereto in a second drive direction to conduct current in a second current direction and thereby tend to drive the armature to a second end position;

B) the endpoint detector responds to the armature'"'"'s reaching the second end position by generating a detector output indicative thereof; and

C) the control circuit is operable to begin application of coil drive to the coil in the second direction at a normal second-direction drive level and, if the detector output has not indicated within a predetermined second drive duration thereafter that the armature has reached the second end position, to apply coil drive to the coil in the second direction at an elevated second-direction drive level higher than the normal second-direction drive level.

8. An actuator system as defined in claim 7 wherein the control circuit stops applying the coil drive in the second direction after the predetermined normal second-direction drive duration before driving the coil at the higher level.

9. An actuator system as defined in claim 1 wherein:

A) the endpoint detector includes a sound sensor that is so coupled to the actuator as to sense sound made by the armature in reaching the first end position and generates a sensor output indicative of the sound that it senses; and

B) the detector output indicates that the armature has reached the first end position if the sensor output meets a predetermined first current-termination criterion.

10. An actuator system as defined in claim 9 wherein the sound sensor includes a piezoelectric transducer.

11. An actuator system as defined in claim 9 wherein:

A) the system includes first and second coil terminals by which the control circuit applies the coil drive to the coil;

B) the system includes first and second sensor terminals by which the control circuit receives the sensor output from the sound sensor; and

C) the second coil and sensor terminals are the same.

12. A flow-control system comprising:

A) a valve operable between open and closed states;

B) a latching actuator including an armature operatively connected to the valve and further including a coil operable by application of a coil drive thereto in a first drive direction to conduct current in a first current direction and thereby tend to drive the armature to a first end position, in which the armature holds the valve in one of said open and closed states;

C) an endpoint detector that detects the armature'"'"'s reaching the first end position and responds thereto by generating a detector output indicative thereof; and

D) a control circuit operable to begin application of coil drive to the coil in the first direction at a normal first-direction drive level and, if the detector output has not indicated within a predetermined first drive duration thereafter that the armature has reached the first end position, to apply coil drive to the coil in the first direction at an elevated first-direction drive level higher than the normal first-direction drive level.

13. A flow-control system as defined in claim 12 wherein:

A) the flow-control system additionally includes an object sensor that produces an object sensor output; and

B) the control circuit'"'"'s application of the coil drive to the coil is dependent on the object-sensor output.

14. A flow-control system as defined in claim 12 wherein:

A) the coil is operable by application of a coil drive thereto in a second drive direction to conduct current in a second current direction and thereby tend to drive the armature to a second end position;

B) the endpoint detector responds to the armature'"'"'s reaching the second end position by generating a detector output indicative thereof; and

C) the control circuit is operable to begin application of coil drive to the coil in the second direction at a normal second-direction drive level and, if the detector output has not indicated within a predetermined second drive duration thereafter that the armature has reached the second end position, to apply coil drive to the coil in the second direction at an elevated second-direction drive level higher than the normal second-direction drive level.

15. A flow-control system as defined in claim 14 wherein:

A) the flow-control system additionally includes an object sensor that produces an object sensor output; and

B) the control circuit'"'"'s application of the coil drive to the coil is dependent on the object-sensor output.

16. A flow-control system as defined in claim 12 wherein:

A) the endpoint detector includes a sound sensor that is so coupled to the actuator as to sense sound made by the armature in reaching the first end position and generates a sensor output indicative of the sound that it senses; and

B) the detector output indicates that the armature has reached the first end position if the sensor output meets a predetermined first current-termination criterion.

17. A flow-control system as defined in claim 16 wherein the sound sensor includes a piezoelectric transducer.

18. A flow-control system as defined in claim 16 wherein:

A) the flow-control system additionally includes an object sensor that produces an object sensor output; and

B) the control circuit'"'"'s application of the coil drive to the coil is dependent on the object-sensor output.

19. For controlling a latching actuator including an armature and a coil operable by application of a coil drive thereto in a first drive direction to conduct current in a first current direction and thereby tend to drive the armature to a first end position, a method comprising the steps of:

A) applying coil drive to the coil in the first drive direction;

B) determining whether the armature has reached the first end position; and

C) if the armature has reached the first end position within a predetermined first drive duration thereafter, applying coil drive to the coil in the first direction at an elevated first-direction drive level higher than the normal first-direction drive level.