Low power electromagnetic valve

• US 4,714,234 A
• Filed: 07/11/1985
• Issued: 12/22/1987
• Est. Priority Date: 09/07/1982
• Status: Expired due to Term

• Current Assignee: Flowonix Medical, Inc.
• Original Assignee: Greatbatch Enterprises, Inc.
• Inventors: Falk, Theodore J., Morris, Lawrence E.
• Primary Examiner(s): Chambers, A. Michael
• Assistant Examiner(s): Fox, John C.
• Application Number:
  US06/754,203
• Time in Patent Office: 894 Days
• Field of Search: 137/375, 251/129, 251/141, 251/335 A, 251/129.17, 604/131, 604/245, 604/249, 604/891
• US Class Current: 251/129.17
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: F16K 31/0655 Lift valves
• CPC Class Codes: Y10T 137/7036 Jacketed

Abstract

An electromagnetic valve comprising a housing having fluid containing region and first and second ports in communication therewith, an electromagnet carried by the housing located external to the region, and a thin fluid impermeable diaphragm barrier hermetically isolating the electromagnet from the region. An armature in the housing is movable within a body of magnetically permeable material and has a pole portion located for magnetic attraction by the electromagnet and has a valve portion located for opening and closing one of the ports to place the ports in fluid communication through the region in one state of the valve and to block fluid communication between the ports in another state of the valve. The armature is moved from a rest position through a forward stroke when attracted by the electromagnet and is returned by a biasing spring to the rest position. A magnetic circuit includes the electromagnet, a portion of the barrier, the body, the armature pole portion and a gap between the pole portion and the electromagnet located in the fluid containing region of the housing which gap is closed during forward movement of the armature. The valve is made electrically and magnetically efficient by minimizing the total gap within the magnetic circuit, by having the armature pole face area relatively large, and by having the electromagnet coil or core of relatively small diameter.

Claims

1. An electromagnetic valve comprising:

(a) a housing including a fluid containing region having first and second chambers and first and second ports in fluid communication with said first and second chambers, respectively;

(b) electromagnet means carried by said housing and located externally of said fluid containing region;

(c) barrier means of fluid-impervious material for isolating said electromagnet means from said fluid containing region of said housing;

(d) an armature movably positioned in said fluid containing region of said housing and having a pole portion located for magnetic attraction by said electromagnet means and located between said first and second chambers and having a valve portion located for opening and closing one of said ports to place said ports in fluid communication through said fluid containing region of said housing in one control state of said valve and to block fluid communication between said ports through said fluid containing region of said housing in another control state of said valve;

(e) a body of magnetically permeable material in said housing fluid containing region between said first and second chambers, said body having a passage therethrough for receiving said armature pole portion in a movable, close-fitting relation whereby said armature moves in said body, said body having a fluid passage therein in fluid communication with said first and second chambers and separate from said armature pole portion receiving passage to allow fluid in said region to flow through said body between said first and second chambers; and

(f) means for defining a magnetic circuit including said electromagnet means, said body, the included portions of said barrier means between said electromagnet means and said body, said armature pole portion and a gap between said pole portion and said electromagnet means located in said fluid containing region of said housing and external to said electromagnet means for closing said gap in response to electrical energization of said electromagnet to move said armature and change the control state of said valve.

2. A valve according to claim 1, further including biasing means operatively engaging said armature for urging said armature to a rest position placing said valve in one of said control states.

3. A valve according to claim 1, wherein said barrier means comprises a thin planar plate of metal and said housing and said electromagnet means are in contact with opposite surfaces of said plate.

4. A valve according to claim 1, wherein said passage in said body has an axial length and an inner surface, said armature pole portion has an outer surface spaced from said inner surface of said passage over a given length thereby defining an effective air gap therebetween and wherein said axial length of said passage in said body is relatively large as compared to said given length of said space between said inner surface of said passage and said outer surface of said armature pole portion to minimize said effective air gap defined therebetween and introduced in said magnetic circuit.

5. A valve according to claim 1, wherein said armature pole portion has a pole face disposed in a plane substantially perpendicular to the direction of movement of said armature, said pole face being located to define said gap with said electromagnet means, said pole face being of relatively large area.

6. A valve according to claim 1, wherein said barrier means comprises a thin plate of metal compatible with fluid in said fluid-containing region of said housing, said plate having opposite surfaces, said electromagnet means includes a housing of magnetically permeable material having an end face contacting one of said surfaces of said plate, and said body of magnetically permeable material having an end face contacting the other of said surfaces of said plate.

7. A valve according to claim 6, wherein the areas of contact of said end faces of said electromagnet housing and said body with said surfaces of said plate are of sufficient size to minimize the effective air gap introduced by said plate in said magnetic circuit.

8. A valve according to claim 1, wherein said electromagnet means comprises a coil wound on a spool within a housing, said electromagnet housing and said valve housing being located on a common axis, and said spool having a relatively small diameter.

9. A valve according to claim 1, wherein each of said body and armature pole portion has an outer surface and is provided with a layer on said outer surface thereof of a material which enhances compatibility of of fluid in said fluid containing region of said housing with said outer surfaces.

10. A valve according to claims 1 or 9, wherein said armature pole portion is provided with an exterior coating of a fluoropolymer material.

11. A valve according to claim 1, wherein said armature comprises a shaft and an enlarged body on one end of said shaft, said body being of magnetically permeable material and terminating in a pole face disposed substantially perpendicular to the axis of said shaft, the cross-sectional area of said pole face being significantly larger than the cross-sectional area of said shaft, said body and shaft being connected together through a bushing of fluoropolymer material.

12. A valve according to claim 1, wherein said housing is elongated having a longitudinal axis, said armature being positioned for movement along said housing longitudinal axis, said fluid containing region of said housing and said electromagnet means being in axially-spaced relation along said housing longitudinal axis, and said barrier means comprises a thin plate of metal compatible with fluid in said fluid containing region of said housing fixed between and providing an hermetic seal between said electromagnet means and said fluid containing region of said housing.

13. A valve according to claim 12, wherein one of said ports is in fluid communication with a chamber defined between said barrier plate and said body, said armature pole portion moves in said chamber and has a pole face on the end thereof disposed toward said barrier plate, and said gap is defined between said armature pole face and said barrier plate, whereby as said gap is reduced during energization of said electromagnet means causing movement of said armature pole face toward said barrier plate said armature valve portion opens the other of said ports.

14. A valve according to claim 12, wherein said electromagnet means includes a housing of magnetically permeable material having an end face contacting one surface of said barrier plate, said body has an end face contacting the other surface of said plate, and the areas of contact of said end faces of said electromagnet housing and said body with said surface of said plate are of sufficient size to minimize the effective air gap introduced by said plate in said magnetic circuit.

15. A valve according to claim 12, wherein said passage in said body has an axial length and an inner surface, said armature pole portion has an outer surface spaced from said inner surface of said passage over a given length thereby defining an effective air gap therebetween and wherein said axial length of said passage in said body is relatively long as compared to said given length of said space between said inner surface of said passage and said outer surface of said armature pole portion to minimize said effective air gap defined therebetween and introduced in said magnetic circuit.

16. In an electromagnetic valve including a housing having an interior fluid containing region including first and second chambers, first and second ports in fluid communication with said first and second chambers, respectively, electromagnet means carried by said housing and located external to said fluid containing region of said housing, and an armature positioned in said fluid containing region of said housing having a pole portion located between said first and second chambers for magnetic attraction by said electromagnet means causing movement of said armature for opening and closing one of said ports, the improvement comprising:

(a) barrier means of fluid-impervious material separating said electromagnet means and said fluid containing region of said housing;

(b) a body of magnetically permeable material in said housing fluid containing region between said first and second chambers and having a passage therethrough for receiving said armature pole portion in a movable, close-fitting relation, said body having a fluid passage therein in fluid communication with said first and second chambers and separate from said armature pole portion receiving passage to allow fluid in said region to flow through said body between said first and second chambers; and

(c) means for defining a magnetic circuit including said electromagnet means, said body, the included portions of said barrier means between said electromagnet means and said body, said armature pole portion and a gap in said fluid containing region of said housing between said armature pole portion and said electromagnet means for moving said armature toward said electromagnet means to close said gap in response to electrical energization of said electomagnet means.

17. An improved electromagnetic valve according to claim 16, wherein said barrier means comprises a thin metal plate fixed between and providing an hermetic seal between said electromagnet and said fluid containing region of said housing and wherein said electromagnet means includes a housing of magnetically permeable material having an end face contacting one surface of said barrier plate, said body has an end face contacting the other surface of said plate, and the areas of contact of said end faces of said electromagnet housing and said body with said surface of said plate are of sufficient size to minimize the effective air gap introduced by said plate in said magnetic circuit.

18. A valve according to claim 16, wherein said passage in said body has an axial length and an inner surface, said armature pole portion has an outer surface spaced from said inner surface of said passage over a given length thereby defining an effective air gap therebetween and wherein said axial length of said passage in said body is relatively long as compared to said given length of said space between said inner surface of said passage and said outer surface of said armature pole portion to minimize said effective air gap defined therebetween and introduced in said magnetic circuit.

19. An electromagnetic valve comprising:

(a) a housing including a fluid containing region and first and second ports in fluid communication with said region, said housing being elongated and having an end;

(b) electromagnet means carried by said housing and located externally of said fluid containing region, said electromagnet means being elongated and having an end;

(c) barrier means of fluid-impervious material for isolating said electromagnet means from said fluid containing region of said housing;

(d) said housing and electromagnet means being positioned in end-to-end relation and said barrier means being located between said ends;

(e) an armature movably positioned in said fluid containing region of said housing and having a pole portion located for magnetic attraction by said electromagnet means and having a valve portion located for opening and closing one of said ports to place said ports in fluid communication through said fluid containing region of said housing in one control state of said valve and to block fluid communication between said ports through said fluid containing region of said housing in another control state of said valve;

(f) a body of magnetically permeable material in said housing fluid containing region between said first and second ports, said body having a passage therethrough for receiving said armature pole portion in a movable, close-fitting relation whereby said armature moves in said body; and

(g) means for defining a magnetic circuit including said electromagnet means, said body, the included portions of said barrier means between said electromagnet means and said body, said armature pole portion and a gap between said pole portion and said electromagnet means located in said fluid containing region of said housing and external to said electromagnet means for closing said gap in response to electrical energization of said electromagnet to move said armature and change the control state of said valve.

20. A valve according to claim 19, wherein said barrier means comprises a thin planar plate of metal and said housing and said electromagnet means are in contact with opposite surface of said plate.