Variable flow electrically controlled valve

• US 5,409,194 A
• Filed: 10/30/1992
• Issued: 04/25/1995
• Est. Priority Date: 04/12/1990
• Status: Expired due to Fees

• Current Assignee: Crouzet Electromenager
• Original Assignee: Crouzet Electromenager
• Inventors: Blanc, Alain, Astic, Georges, Vollot, Jean, Dejoux, Didier, Girardin, Denis
• Primary Examiner(s): Walton, George L.
• Application Number:
  US07/970,407
• Time in Patent Office: 907 Days
• Field of Search: 251/6, 251/7, 251/8, 251/9, 251/129.01, 251/129.04, 251/129.11, 251/129.12, 251/249.5, 251/250.5, 604/245, 604/250, 604/253, 604/246, 137/486, 137/487.5, 137/2, 137/624.11, 137/624.13, 137/624.15
• US Class Current: 251/9
• CPC Class Codes: F16K 7/045 by electric or magnetic means
• CPC Class Codes: G05B 11/28 using pulse-height modulation; using pulse-width modulation
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence

Abstract

A method for controlling a valve including a direct current motor acting upon an aperture adjusting part (3) against the force of elastic means (11) biasing the aperture adjusting part towards a zero flow rest position, comprising the steps of: selecting a desired valve aperture; determining a time interval (T_a) as a function of the desired valve aperture; supplying the motor with a first constant current of a sufficient value for rotating the motor, during the mentioned time interval; supplying the motor with a second constant low value current thereafter until a next valve aperture is selected, this low value current being sufficient to hold the motor in its position against the force of the elastic means.

Claims

1. A method for controlling a valve including a direct current motor reversibly engaged with a valve aperture adjusting part biased by elastic means so that, when the motor is not powered, the valve aperture adjusting part moves to establish a zero flow rest position, comprising the steps of:

selecting a desired valve aperture flow position;

determining a time interval required for the direct current motor to provide the desired valve aperture flow position;

throughout the duration of said time interval, supplying the motor with a first constant current of a sufficient value for rotating the motor against the force of said elastic means to move a valve element to said desired valve aperture flow position;

supplying the motor with a second constant low value current after said time interval until a next valve aperture flow position has been selected, said low value current being insufficient to rotate the motor but sufficient to hold the motor in its position against the force of said elastic means for

maintaining said valve element in said desired valve aperture desired position.

2. A method as claimed in claim 1, wherein the supply current of the motor is first cancelled when said valve aperture flow position is selected, so that the valve aperture adjusting part moves to establish said zero flow rest position before supplying said first constant current during said time interval.

3. A circuit for controlling a valve including a direct current motor reversibly engaged with a valve aperture adjusting part biased by elastic means so that, when the motor is not powered, the valve aperture adjusting part moves to establish a zero flow rest position, comprising:

a selection means for selecting a desired valve aperture flow position and determining a time interval required for the direct current motor to provide said desired valve aperture flow position; and

a power supply device for supplying said motor with a first constant current throughout the duration of said time interval, said first current being of a sufficient value to rotate the motor against the force of said elastic means for moving a valve element to said desired valve aperture flow position, said power supply device supplying said motor with a second constant low value current after said time interval until a next valve aperture flow position selection has been established, said low value current being insufficient to rotate the motor but sufficient to hold the motor in its position against the force of said elastic means for maintaining said value element in said desired valve aperture desired position.

4. A circuit as claimed in claim 3, comprising means for first cancelling the current supplied to the motor when said valve aperture flow position is selected, so that the valve aperture adjusting part moves to establish said zero flow rest position before supplying said first constant current during said time interval.

5. A circuit as claimed in claim 3, comprising:

a voltage variation detector receiving as an input a valve aperture reference voltage and providing a detection signal at an active state as long as the reference voltage varies;

a temporizer operable to be initialized by said active state and to count a delay determined by said reference voltage; and

means associated to said temporizer for providing the motor with a zero voltage sufficient for rotating the motor when the temporizer counts said delay, and with a voltage sufficient for maintaining the motor in its position at the end of said delay.

6. A circuit as claimed in claim 5, wherein said temporizer comprises a comparator comparing said reference voltage with the voltage across a capacitor charged by a current source, a switching means being placed between said capacitor and the output of the detector for discharging the capacitor when the detection signal is active.

7. A circuit as claimed in claim 6, wherein said means associated to the temporizer comprise a dividing bridge connected between the output of the comparator and a high voltage, the signal present at an intermediate node of said dividing bridge being amplified in current and applied across the motor, a switching means being placed between said intermediate node of the bridge and the output of the detector for canceling the voltage at this intermediate node when the detection signal is active.

8. A circuit as claimed in claim 5, wherein said detector comprises at least an arrangement constituted of a comparator receiving at an input said reference voltage and at the other input said reference voltage through a low-pass filter, and of a resistor connected between a suitable voltage and one of the inputs of the comparator so that said comparator supplies an inactive detection signal at rest.

9. A variable flow electrically controlled valve comprising, in a housing, a tube made of elastic material through which a fluid can flow, and a control device causing a variable pinching of said tube, wherein said control device comprises:

a valve aperture adjusting part mounted on an articulation of said housing and comprising a pressing area to pinch said tube as well as a toothed sector centered on the axis of the articulation;

a pinion mounted to rotate in said housing and forming with the toothed sector a reversible meshed gear;

a direct current electric motor engaged with said pinion to move said valve aperture adjusting part;

an elastic means biasing said valve aperture adjusting part so that, when the motor is not powered, the valve aperture adjusting part moves to establish a full pinching position of said tube;

a selection means for selecting a desired valve aperture flow position and determining a time interval required for said control device to provide said desired valve aperture flow position; and

a power supply device for supplying said motor with a first constant current throughout the duration of said time interval, said first current being of a sufficient value for rotating the motor against the force of said elastic means to move a valve element to said desired valve aperture flow position, said power supply device supplying said motor with a second constant low value current after said time interval until a next valve aperture flow position selection has been established, said low value current being insufficient to rotate the motor but sufficient to hold the motor in its position against the force of said elastic means for maintaining said valve element in said desire valve aperture desired position.

10. A valve as claimed in claim 9, wherein the power supply device comprises means for first cancelling the current supplied to the motor when said valve aperture flow position is selected, so that the valve aperture adjusting part moves to establish said full pinching position before supplying said first constant current during said time interval.