Electromagnetic valve with permanent magnet armature

• US 4,690,371 A
• Filed: 10/22/1985
• Issued: 09/01/1987
• Est. Priority Date: 10/22/1985
• Status: Expired due to Term

• Current Assignee: Celerity Incorporated (ICHOR Holdings, Ltd.)
• Original Assignee: Innovus
• Inventors: Kirshman, Samson, Renken, Wayne G., Bosley, Robert W., LeMay, Dan B.
• Primary Examiner(s): Rosenthal, Arnold
• Application Number:
  US06/790,279
• Time in Patent Office: 679 Days
• Field of Search: 251/65, 251/129.08, 251/129.1, 251/129.21, 251/129.01
• US Class Current: 251/65
• CPC Class Codes: F16K 31/082 using a electromagnet and a permanent magnet
• CPC Class Codes: H01F 7/122 by permanent magnets H01F7/1615, H01F7/1646 take precedence
• CPC Class Codes: H01F 7/1615 Armatures or stationary parts of magnetic circuit having permanent magnet
• CPC Class Codes: H01F 7/18 Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings

Abstract

A modulating valve is described for controlling the flow of a working fluid through a flow orifice. The valve includes a encapsulated armature having a permanent magnet and a pair of soft iron pole pieces within its interior. The armature is axially movable by the passage of current through one or a dual pair of solenoid coils surrounding the armature. A thin webbed sealing disk is stretched over the end of an armature housing extension and acts to close or modulate flow of working fluid by varying the axial clearance between the disk and a stationary annular seat of the flow orifice. The armature is supported on flexure guide springs that allow armature axial motion when axial magnetic forces are applied to the armature. These axial forces are provided by the interaction of the solenoid coil(s) and the field of the permanent magnet. A magnetic field gradient produced by the permanent magnet allows the coil to apply a force to the armature in either the valve opening or valve closing direction, depending on the coil current polarity. An armature velocity signal is used in a closed loop servo control of valve position to suppress valve oscillation and over shoot when a change in valve position is commanded.

Claims

1. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil;

further including a first magnetically inert cylindrical housing extending interiorly of said at least one annular solenoid coil;

a second magnetically inert cylindrical housing annularly spaced interiorly of said first magnetically inert cylindrical housing forming a first flow passage therebetween;

said cylindrical armature housing having an outer peripheral surface annularly spaced from said second magneticcally inert cylindrical housing forming a second flow passage therebetween; and

wherein said permanent magnet and said at least one annular solenoid coil are remote from said first and second flow passages.

2. The valve of claim 1 in which said cylindrical armature housing is made from an impermeable chemically resistant nonmagnetic material.

3. A controller for opening and modulating a modulating valve having

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat; and

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil, said controller comprising;

means for deriving a velocity-dependent signal from a back emf generated by the movement of said cylindrical armature housing and said permanent magnet and the resultant changing magnetic field'"'"'s effect on a current/voltage relationship of current flowing through said at least one annular solenoid coil; and

means, including a feedback loop, for utilizing said veloicity-dependent signal for reducing overshoot of said cylindrical armature and enhancing the speed of response and stability of said valve to dynamic changes.

4. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil; and

wherein

said at least one annular solenoid coil comprises a single coil and further including dual magnetic return paths, wherein one of said magnetic return paths is connected to a magnetic field sensor providing a position or velocity signal from the magnetic field of said permanent magnet within said cylindrical armature housing, and a control circuit means for utilizing said position or velocity signal in a feedback loop to reduce over shoot of said moving cylindrical armature housing.

5. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature asembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil; and

further comprising

an electrical supply to said at least one annular solenoid coil including a capacitive-resistive output impedance such that back emf dynamic damping produced by movement of said cylindrical armature housing is enhanced.

6. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil; and

wherein said at least one annular solenoid coil is driven by a variable current source and a coil voltage is sensed and compared with asynthesized voltage signal derived from the coil drive current and representing the voltage with the armature motionless, said comparison providing a signal indicative of armature velocity.

7. The valve of claim 6 in which said armature velocity signal is utilized in a feedback loop to provide means for reducing overshoot and optimizing the dynamic response and stability of the valve.

8. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil; and

wherein said at least one annular solenoid coil is driven by a variable voltage source and a coil current is sensed and compared with a synthesized signal derived from the coil drive voltage and representing the current with the armature motionless, said comparison providing a signal indicative of armature velocity.

9. The valve of claim 8 in which said armature velocity signal is utilized in a feedback loop to provide means for reducing overshoot and optimizing the dynamic response and stability of the valve.

10. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical armature housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any displaced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil; and

wherein

said valve seal comprises a circular elastomeric disk having a thin central web and an outer integral circular annular toroidal bead.

11. The valve of claim 10 in which said annular toroidal bead is circular and has a diameter greater than the axial thickness of said thin central web.

12. The valve of claim 11 in which said cylindrical armature housing has a central extension and wherein said seal central web abuts and is supported by said central extension.

13. A modulating valve comprising:

a flow orifice having an orifice seat;

an armature assembly including a valve seal on an axial end of said armature assembly, said valve seal being axially oriented with respect to said orifice seat;

at least one annular solenoid coil;

said armature assembly including a cylindrical aramture housing confined within an annulus formed by said at least one annular solenoid coil and moveable axially with respect to said at least one annular solenoid coil to any dispalced selected position between a full open and close position of said valve seal and said orifice seat;

a permanent magnet fixedly mounted in said cylindrical armature housing axially within said annulus of said at least one annular solenoid coil; and

including a ferroimagnetic housing, a ferromagnetic disk dividing said housing into dual magnetic field paths, a first path containing said at least one annular solenoid coil and a second path including a velocity or position sensor.