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Patent Abstract
A device comprised of a solenoid portion and a valve unit. The solenoid
portion is comprised of a coil with a bore therethrough, a fixed
magnetic pole piece substantially within the coil bore, an axially
translatable armature forming an axial air gap between the armature
and the pole piece, and a biasing mechanism. The valve unit is mechanically
coupled to the solenoid valve and comprised of a base member with
a chamber, fluid input and exit ports defined by a base member,
a valve seat with a valve seat bore, and a poppet assembly within
said chamber and mechanically coupled to the armature. The poppet
assembly is comprised of a poppet with a lapped surface and a poppet
cavity. The lapped surface creates a fluid seal with the valve seat.
When the solenoid coil is subject to an electric current, the poppet
assembly, mechanically coupled to the armature, axially translates
from the valve seat, allowing a fluid to exit the solenoid valve
proportional to the electric signal applied to the device. In an
alternate embodiment, the armature includes a ferrule-shaped portion
disposed thereon, further forming a radial air gap with the magnetic
pole piece, whereby the magnetic flux is directed across the radial
air gap instead of the axial air gap. In another alternate embodiment
of the armature, the ferrule-shaped portion is tapered.
Patent Claims
What is claimed is:
1. A device comprised of: a solenoid portion comprised of: a generally
cylindrical solenoid coil having a longitudinal axis and a coil
bore therein, and being operative to produce a magnetic flux with
a magnetic flux path when subject to an electric signal; a generally
cylindrical fixed magnetic pole piece disposed within said coil
bore and having a distal end projecting from said coil bore; a generally
cylindrical and magnetic axially translatable armature with a ferrule-shaped
portion disposed thereon, said ferrule-shaped portion having an
inner diameter slightly larger than said distal end of said magnetic
pole piece and forming a first radial air gap and an axial air gap
therebetween, said first radial air gap substantially reducing an
axial magnetic flux of said magnetic flux across said axial air
gap; and a biasing mechanism functionally engaging said magnetic
pole piece and said armature and adapted to exert a biasing force
on said armature in a direction away from said magnetic pole piece;
and a valve unit mechanically coupled to said solenoid portion,
said valve unit comprised of: a base member, said base member defining
a chamber; a fluid input port and a fluid exit port defined by said
base member; a valve seat with a valve seat bore, said valve seat
fluidly adjacent to said chamber and protruding at least partly
into said chamber; a poppet assembly mechanically coupled to said
armature and substantially within said chamber, wherein said poppet
assembly is comprised of: a poppet with a lapped surface and a poppet
cavity, wherein said lapped surface is capable of creating a fluid
seal with said valve seat; a poppet balance stem with a distal end
and a proximal end, said distal end being mechanically coupled to
said armature; a ball on said proximal end of said poppet balance
stem, said ball sized to fit within said poppet cavity and making
a pivotal connection with said ball; and a poppet cap for retaining
said ball within said poppet cavity; such that when said solenoid
coil is subject to said electric signal, said poppet assembly, being
mechanically coupled to said armature, axially translates away from
said valve seat, allowing a fluid to pass from said chamber, through
said valve seat bore, and out of said device via said fluid exit
port in proportion to said electric signal.
2. The device of claim 1, wherein said device is further comprised
of a calibration mechanism to establish an amount of force required
to axially translate said armature.
3. The device of claim 2, wherein said magnetic pole piece is further
comprised of a generally cylindrical axial pole piece bore therewith,
said calibration mechanism being disposed substantially within said
pole piece bore and comprised of a shaft member, an armature-biasing
axial pin with a first end and a second end, said first end of said
armature-biasing axial pin functionally engaging said armature and
said second end of said armature-biasing axial pin functionally
engaging said shaft member, and a calibration member functionally
engaging said shaft member, said calibration member configured to
adjust said amount of force required to axially translate said armature.
4. The device of claim 1, wherein said magnetic pole piece and
said armature are made of a material selected from a magnetic iron,
a magnetic steel, a silicon-iron alloy, a cold-rolled steel, and
a ferro-magnetic material.
5. The device of claim 1, wherein said device further includes
a housing, said housing substantially enclosing said solenoid portion
and being of a ferro-magnetic material or further including a C-shaped
electrical connector for completing said magnetic flux path.
6. The device of claim 5, wherein said magnetic housing is further
comprised of an inwardly projecting tapered portion of said housing
and said armature is further comprised of a disc-shaped rim portion,
forming a variable geometry radial air gap therebetween, wherein
said variable geometry radial air gap aids said first radial air
gap in reducing said magnetic flux path across said axial air gap.
7. The device of claim 1, wherein said device is further comprised
of a ledge element and said armature is further comprised of a disc-shaped
rim portion, said ledge element forming a second radial air gap
therebetween, through which said magnetic flux path passes, wherein
said second radial air gap aids said first radial air gap in reducing
said magnetic flux path across said axial air gap.
8. The device of claim 7, wherein said device further includes
an annular ring disposed atop said ledge element to support said
pole piece within said solenoid coil bore, said annular ring being
made of a non-magnetic material.
9. The device of claim 1, wherein said ferrule-shaped portion of
said armature is tapered.
10. The device of claim 1, wherein said biasing mechanism is selected
from a group comprised of: gravity; fluid pressure; a biasing member,
said biasing member disposed within said ferrule-shaped portion
of said armature and selected from a group comprised of a compression
spring, a flexible tube, a star spring with a memory, a sponge,
and a geo-spring; and a biasing pin with a proximal end and a distal
end and said magnetic pole piece is further comprised of a bore
substantially therethrough, said biasing pin being at least partially
within said bore and said distal end of said biasing pin protruding
outside of said pole piece bore, and wherein said distal end is
mechanically coupled to said armature and said proximal end is mechanically
coupled to a biasing member, said biasing member being selected
from a group comprised of a compression spring, a flexible tube,
a star spring with a memory, a sponge, and a geo-spring.
11. The device of claim 10, wherein said armature is further comprised
of a generally cylindrical bore and an armature retainer disposed
within and functionally engaging said armature, wherein said biasing
pin is mechanically coupled at said distal end to said armature
retainer.
12. The device of claim 1, wherein said armature is supported for
axial translation relative to said pole piece by a support mechanism
external to said coil bore, wherein said support mechanism is a
first and a second flat suspension spring spaced apart from one
another and mechanically coupled to said armature.
13. The device of claim 1, wherein said valve seat is defined by
said base member.
14. The device of claim 1, wherein said valve seat is further comprised
of a cylindrical lip, an insert disposed on said cylindrical lip,
and at least one fluid sealing member located between said insert
and said base member, wherein said at least one fluid sealing member
is selected from a group comprised of an O-ring.
15. The device of claim 5, wherein said housing further includes
a housing extension extending at least partially within said base
member of said valve unit such that said housing extension and said
base member define said chamber within said base member.
16. The device of claim 1, wherein said poppet cavity is further
comprised of a depression, and wherein said poppet is locked into
a position around said ball using a potting compound such that said
lapped surface of said poppet is flush with said valve seat when
said solenoid is de-energized.
17. A solenoid valve comprised of: a solenoid portion comprised
of: a generally cylindrical solenoid coil having a longitudinal
axis and a coil bore therein, and being operative to produce a magnetic
flux with a magnetic flux path when subject to an electric signal;
a generally cylindrical fixed magnetic pole piece disposed within
said coil bore and having a distal end projecting from said coil
bore; a generally cylindrical and magnetic axially translatable
armature with a tapered and ferrule-shaped portion disposed thereon,
said ferrule-shaped portion having an inner diameter slightly larger
than said distal end of said magnetic pole piece and forming a first
radial air gap and an axial air gap therebetween, said first radial
air gap substantially reducing an axial magnetic flux path across
said axial air gap so that, during relative axial translation between
said armature and said pole piece, said magnetic flux path is directed
in a radial direction across said first radial air gap, substantially
by-passing said axial air gap; and a biasing mechanism functionally
engaging said magnetic pole piece and said armature and adapted
to exert a biasing force on said armature in a direction away from
said magnetic pole piece; and a valve unit mechanically coupled
to said solenoid portion, said valve unit comprised of: a base member,
said base member defining a chamber; a fluid input port and a fluid
exit port defined by said base member; a valve seat with a valve
seat bore, said valve seat fluidly adjacent to said chamber and
protruding at least partly into said chamber; a poppet assembly
mechanically coupled to said armature and substantially within said
chamber, wherein said poppet assembly is comprised of: a poppet
with a lapped surface and a poppet cavity, wherein said lapped surface
is capable of creating a fluid seal with said valve seat; a poppet
balance stem with a distal end and a proximal end, said distal end
being mechanically coupled to said armature; a ball on said proximal
end of said poppet balance stem, said ball sized to fit within said
poppet cavity and being pivotal connected to said ball; and a poppet
cap for retaining said ball within said poppet cavity, wherein said
poppet is locked into a position around said ball using a potting
compound such that said lapped surface of said poppet is flush with
said valve seat when said solenoid is de-energized; such that when
said solenoid coil is subject to said electric signal, said poppet
assembly, being mechanically coupled to said armature, axially translates
away from said valve seat, allowing a fluid to pass from said chamber,
through said valve seat bore, and out of said solenoid valve via
said fluid exit port, varying in proportion to said electric signal.
18. The device of claim 17, wherein said device is further comprised
of a calibration mechanism to establish an amount of force required
to axially translate said armature.
19. The device of claim 18, wherein said magnetic pole piece is
further comprised of a generally cylindrical axial pole piece bore
therewith, said calibration mechanism being disposed substantially
within said pole piece bore, and said calibration mechanism is comprised
of a shaft member, an armature-biasing axial pin with a first end
and a second end, said first end of said armature-biasing axial
pin functionally engaging said armature and said second end of said
armature-biasing axial pin functionally engaging said shaft member,
and a calibration member functionally engaging said shaft member,
said calibration member configured to adjust said amount of force
required to axially translate said armature.
20. The solenoid valve of claim 18, wherein said magnetic pole
piece and said armature are made of a material selected from magnetic
iron, magnetic steel, a silicon-iron alloy, cold-rolled steel, and
a ferro-magnetic material.
21. The solenoid valve of claim 18, wherein said solenoid valve
further includes a housing, said housing substantially enclosing
said solenoid portion and being of a ferro-magnetic material or
further including a C-shaped electrical connector for completing
said magnetic flux path.
22. The solenoid valve of claim 21, wherein said magnetic housing
is further comprised of an inwardly projecting tapered portion of
said housing and said armature is further comprised of a disc-shaped
rim portion, forming a variable geometry radial air gap therebetween,
wherein said variable geometry radial air gap aids said radial air
gap in reducing said magnetic flux path across said axial air gap
23. The solenoid valve of claim 17, wherein said solenoid valve
is further comprised of a ledge element and said armature is further
comprised of a disc-shaped rim portion, said ledge element forming
a second radial air gap therebetween, through which said magnetic
flux path passes, wherein said second radial air gap aids said radial
air gap in reducing said magnetic flux path across said axial air
gap.
24. The solenoid valve of claim 23, wherein said solenoid valve
further includes an annular ring disposed atop said ledge element
to support said pole piece within said solenoid coil bore, said
annular ring being made of a non-magnetic material.
25. The solenoid valve of claim 17, wherein said biasing mechanism
is selected from a group comprised of: gravity; fluid pressure;
a biasing member, said biasing member disposed within said ferrule-shaped
portion of said armature and selected from a group comprised of
a compression spring, a flexible tube, a star spring with a memory,
a sponge, and a geo-spring; and a biasing pin with a proximal end
and a distal end and said magnetic pole piece is further comprised
of a bore substantially therethrough, said biasing pin being at
least partially within said bore and said distal end of said biasing
pin protruding outside of said pole piece bore, and wherein said
distal end is mechanically coupled to said armature and said proximal
end is mechanically coupled to a biasing member, said biasing member
being selected from a group comprised of a compression spring, a
flexible tube, a star spring with a memory, a sponge, and a geo-spring.
26. The solenoid valve of claim 25, wherein said armature is further
comprised of a generally cylindrical bore and an armature retainer
disposed within and functionally engaging said armature, wherein
said biasing pin is mechanically coupled at said distal end to said
armature retainer.
27. The solenoid valve of claim 17, wherein said armature is supported
for axial translation relative to said pole piece by a support mechanism
external to said solenoid coil bore, wherein said support mechanism
is a first and a second flat suspension spring spaced apart from
one another and mechanically coupled to said armature.
28. The solenoid valve of claim 17, wherein said valve seat is
defined by said base member or said valve seat is further comprised
of a cylindrical lip, an insert disposed on said cylindrical lip,
and at least one fluid sealing member located between said insert
and said base member, wherein said at least one fluid sealing member
is an O-ring.
29. The solenoid valve of claim 21, wherein said housing further
includes a housing extension extending at least partially within
said base member of said valve unit such that said housing extension
and said base member define said chamber within said base member.
30. The solenoid valve of claim 17, wherein said poppet cavity
is further comprised of a depression.
31. The solenoid valve of claim 17, wherein said poppet is locked
into a position around said ball using a potting compound such that
said lapped surface of said poppet is flush with said valve seat
when said solenoid is de-energized.
32. A device comprised of: a base member, said base member defining
a chamber: a fluid input port and a fluid exit port defined by said
base member; a valve seat with a valve seat bore, said valve seat
fluidly connected to said chamber and protruding at least partly
into said chamber; a poppet assembly mechanically coupled to said
armature and substantially within said chamber, wherein said poppet
assembly is comprised of: a poppet with a lapped surface and a poppet
cavity, wherein said lapped surface is capable of creating a fluid
seal with said valve seat; a poppet balance stem with a distal end
and a proximal end, said distal end being mechanically coupled to
said armature; a ball on said proximal end of said poppet balance
stem, said ball sized to fit within said poppet cavity and making
a pivotal connection with said ball; and a poppet cap for retaining
said ball within said poppet cavity.
33. The device of claim 32, wherein said valve unit is capable
of being mechanically coupled to a solenoid sub-assembly comprised
of a generally cylindrical solenoid coil being operative to produce
a magnetic field when subject to an electric signal and having a
solenoid bore therein, a generally cylindrical fixed magnetic pole
piece disposed substantially within said solenoid bore, a generally
cylindrical axially translatable armature external to said solenoid
bore, and a biasing mechanism exerting a biasing force on said armature
directed away from said magnetic pole piece, wherein when said solenoid
coil is subject to said electric signal, said poppet assembly, being
mechanically coupled to said armature, axially translates from said
valve seat, allowing a fluid to pass from said chamber, through
said valve seat bore, and out of said device via said fluid exit
port, in proportion to said electric signal.
34. The device of claim 32, wherein said a base member, said poppet,
said poppet balance stem, said ball, and said poppet cap are made
of a magnetic material or a non-magnetic material.
35. The device of claim 32, wherein said valve seat is defined
by said base member.
36. The device of claim 32, wherein said valve seat is further
comprised of a cylindrical lip, an disposed on said cylindrical
lip and at least one fluid sealing member located between said insert
and said base member, wherein said at least one fluid sealing member
is selected from a group comprised of an O-ring.
37. The device of claim 33, wherein said solenoid sub-assembly
further includes a housing and a housing extension extending at
least partially within said base member of said valve unit such
that said housing extension and said base member define said chamber
within said base member.
38. The device of claim 33, wherein said distal end of said poppet
balance stem is mechanically coupled to said armature via an armature
retainer within said armature.
39. The device of claim 32, wherein said poppet cavity is further
comprised of a depression.
40. The device of claim 32, wherein said poppet is locked into
a position around said ball using a potting compound such that said
lapped surface of said poppet is flush with said valve seat when
said solenoid is de-energized.
41. A method for creating a custom-fit seat between a poppet assembly
and a valve seat for use with a solenoid valve comprised of the
following steps: providing a poppet with a lapped surface and a
poppet cavity, wherein said lapped surface is capable of creating
a fluid seal with said valve seat; providing a poppet balance stem
with a distal end and a proximate end, said distal end capable of
being mechanically coupled to an axially translatable armature,
and a ball disposed on said proximate end of said poppet balance
stem, said ball sized to fit within said poppet cavity and making
a pivotal connection to said ball; and depositing a potting compound
into said poppet cavity, wherein said poppet cavity is at least
partially filled with said potting compound; inserting said ball
into said poppet cavity; locking said ball within said poppet cavity
with a poppet cap; lowering said poppet assembly against said valve
seat; repeating said lowering step as necessary to ensure that said
lapped surface of said poppet is substantially flush against said
lapped valve seat; and allowing said potting compound to cure so
that said poppet can no longer pivot around said ball.
42. The method of claim 41, wherein said valve unit is comprised
of a base member with a chamber, a fluid input port, and a fluid
exit port, wherein said base member defines said chamber and said
poppet assembly is disposed substantially within said chamber.
43. The method of claim 41, wherein said valve unit is capable
of being mechanically coupled to a solenoid portion comprised of
a generally cylindrical solenoid coil being operative to produce
a magnetic field when subject to an electric signal and having a
solenoid bore therein, a generally cylindrical fixed magnetic pole
piece disposed substantially within said solenoid bore, a generally
cylindrically axially translatable armature external to said solenoid
bore, and a biasing member exerting a biasing force against said
armature in a direction away from said magnetic pole piece.
44. The method of claim 43, wherein when said solenoid coil is
subject to said electric current, said poppet assembly, being mechanically
coupled to said armature, axially translates from said valve seat,
allowing a fluid to pass from said chamber of said base member,
through said valve seat bore, and out of said device via said fluid
exit port, in proportion to said electric signal.
45. The method of claim 41, wherein said distal end of said poppet
balance stem is mechanically coupled to said armature via an armature
retainer within said armature.
46. The method of claim 41, wherein said valve seat is further
comprised of an insert sitting atop a cylindrical lip and at least
one fluid sealing member located between said insert and said base
member, said at least one fluid sealing member selected from a group
comprised of an O-ring.
47. The method of claim 41, wherein said poppet cavity is further
comprised of a depression.
Patent Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to provisional patent application
Ser. No. 60/533,562, filed Dec. 31, 2003, which is a continuation-in-part
of and claims priority to non-provisional patent application Ser.
No. 09/846,425, filed May 1, 2001 and issued as U.S. Pat. No. 6,715,732
on Apr. 6, 2004, which is a continuation-in-part of and claims priority
to non-provisional patent application Ser. No. 09/535,757, filed
on Mar. 28, 2000 and issued as U.S. Pat. No. 6,224,033 on May 1,
2001, which is a continuation of and claims priority to application
Ser. No. 08/988,369, filed Dec. 10, 1997 and issued as U.S. Pat.
No. 6,047,947 on Apr. 11, 2000, which is a continuation-in-part
of and claims priority to application Ser. No. 08/632,137, filed
Apr. 15, 1996 and issued as U.S. Pat. No. 5,785,298 on Jul. 28,
1998, all of which are incorporated herein in their entireties.
FIELD OF INVENTION
[0002] This invention relates generally to proportional solenoid-controlled
fluid valves and poppet assemblies. More particularly, but not by
way of limitation, the invention relates a to proportional solenoid-controlled
fluid valve, with a custom-fit, poppet assembly, and a method for
creating the custom-fit poppet assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 shows one embodiment of the entire valve assembly
for reference.
[0004] FIG. 2 shows an enlarged portion of the valve assembly,
similar to that of FIG. 1.
[0005] FIG. 3 shows an alternate embodiment of the entire valve
assembly.
[0006] FIG. 4 shows an enlarged alternate embodiment of a portion
of the valve assembly.
[0007] FIG. 5 shows an alternate embodiment of the entire valve
assembly.
[0008] FIG. 6 shows an alternate embodiment of the valve unit portion
of the valve assembly.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0009] While the device is susceptible to various alternative forms
and modifications, specific embodiments will be shown by way of
example in the drawings and will be described herein in detail.
However, it should be understood that the invention is not intended
to be limited to the particular embodiments disclosed. Rather, it
is intended that the invention covers all modifications, equivalents,
and alternatives following within the spirit and scope of the invention
as defined by the claims.
[0010] Furthermore, with reference to the drawings, the reader
should understand that like reference numerals in different drawings
refer to the like elements and components of the invention. The
respective elements are generally cylindrically symmetric about
an axis of symmetry A. Moreover, it should be noted that every possible
alternate embodiment of the invention is not depicted by the figures.
[0011] The term "fluid" is used herein to describe any
substance with a flow capable of being controlled by a valve, be
it a gas or liquid.
[0012] Precision fluid flow control devices, such those used in
fuel supply units for aerospace systems and oxygen/air metering
units employed in hospitals, as non-limiting examples, often incorporate
a solenoid-operated valve for controlling fluid flow substantially
proportional to the electric signal applied to the solenoid. As
the electric signal applied to the solenoid coil increases, a fixed
magnetic pole piece becomes more magnetized and an axially translatable
armature moves in the direction of the pole piece. The axial translation
either opens or closes the valve depending on whether the valve
is open or closed when the solenoid is de-energized.
[0013] Referring now to the drawings, FIG. 1 shows one embodiment
of the entire valve assembly 100 for reference, which is comprised
of valve unit 300 and solenoid portion 200, which is mechanically
joined to valve unit 300 for controlling operation of valve assembly
100. Valve unit 300 is shown as being threadedly engaged to solenoid
portion 200 via housing extension 231, but one of ordinary skill
in the art will recognize that valve unit 300 and solenoid portion
200 could be mechanically coupled by any means that prevents fluid
leakage therebetween.
[0014] In the embodiment shown in FIG. 1, solenoid portion 200
is comprised of solenoid coil 210, with an axial coil bore 211 therethrough,
and fixed magnetic pole piece 220 disposed within coil bore 211,
both of which are contained within, and supported by, a generally
cylindrical magnetic housing 230. However, it should be recognized
that valve assembly 100 could be constructed without housing 230,
as discussed in detail infra.
[0015] As can more readily be seen in FIG. 2, which shows an enlarged
version of a portion of valve assembly 100, similar to that of FIG.
1, generally cylindrical and axially translatable armature 270 can
be seen, which is substantially adjacent to end 222 of magnetic
pole piece 220 and constrained to only axial movement. End 222 of
magnetic pole piece 220 protrudes outside of coil bore 211. Armature
270 is comprised of disc-shaped rim portion 273 and ferrule-shaped
portion 271 projecting from armature 270. In addition, armature
270 can be constructed such that rim portion 273 and ferrule-shaped
portion 271 are one integral unit or as separate elements fixedly
secured to one another. The hollow region, or interior recess 277,
of ferrule-shaped portion 271 has an inner diameter that is only
slightly larger than the diameter of end 222 of fixed magnetic pole
piece 220. This slightly larger diameter allows for relative axial
translation of armature 270 between armature 270 and end 222 of
magnetic pole piece 220 as armature 270 is attracted to and axially
translates towards solenoid coil 210 when energized.
[0016] Also visible in FIG. 2 (though not shown in the embodiment
of FIG. 1) is annular ring 205 which is made of a non-magnetic material
to provide additional structural support. Annular ring 205 is sized
to provide a cavity from which end 222 of magnetic pole piece 220
protrudes, and which accommodates axial displacement of ferrule-shaped
portion 271 of armature 270.
[0017] As can also be seen in FIGS. 1 and 2, end 222 of magnetic
pole piece 220 is of a smaller diameter than that of the rest of
magnetic pole piece 220. However, as can be seen in the embodiment
of valve assembly 100 depicted FIG. 3, end 222 need not be of a
smaller diameter as compared to the rest of magnetic pole piece
220.
[0018] Referring again to FIG. 1, FIG. 1 shows one example of a
biasing mechanism. Within magnetic pole piece 220 is pole piece
bore 221. At least substantially within pole piece bore 221 is armature-biasing
axial pin 215 attached on a distal end to armature 270 and on a
proximal end to biasing member 260, which is, in this embodiment,
a compression spring. Biasing member 260 maximizes the axial distance
between armature 270 and end 222 of magnetic pole piece 220 when
solenoid coil 210 is de-energized, and provides the force that must
be overcome when solenoid coil 210 is subject to an electric signal.
[0019] Armature-biasing axial pin 215 and biasing member 260 comprise
one embodiment of the biasing mechanism. One of ordinary skill in
the art will recognize that alternate biasing mechanisms could be
employed to bias armature 270 away from magnetic pole piece 220.
For example, biasing member 260 could be a flexible tube, a star
spring with a memory, a sponge, a geo spring, fluid pressure, gravity,
or any other means for biasing armature 270 away from magnetic pole
piece 220. In addition, instead of biasing member 260 and armature-biasing
axial pin 215, the biasing mechanism could be a biasing member,
selected from those listed supra, or another, placed within interior
recess 277 (see FIG. 2) of armature 270 between and functionally
engaging armature 270 and magnetic pole piece 220.
[0020] Referring again to FIG. 2, armature retainer 280 can also
be seen, which is sized to be threaded into armature 270 and provides
one example of an attachment mechanism between armature 270 and
armature-biasing axial pin 215. Armature retainer 280 further includes
cylindrical wall portion 281, which is sized to receive an inner
spring-retaining, ferrule-shaped spacer 285, and also includes a
generally flat, rim portion 286, which extends radially from and
is solid with wall portion 281. By threading armature retainer 280
into armature 270, first and second spiral-configured suspension
spring members 290 and 291, adjoining and mutually spaced apart
by spacer 285, are captured between lower face 272 of armature 270
and rim portion 286 of armature retainer 280, thereby providing
a support mechanism for armature 270 when solenoid coil 210 is de-energized.
[0021] There are two air gaps between armature 270 and magnetic
pole piece 220. The first is radial air gap 235 between the outer
surface of end 222 of magnetic pole piece 220 and the inner surface
of ferrule-shaped portion 271. The second is axial air gap 238 between
the bottom surface of end 222 of magnetic pole piece 220 and the
circular inner surface 274 within interior recess 277 formed by
ferrule-shaped portion 271 of armature 270. Radial air gap 235,
a path of low reluctance, shunts a portion of the magnetic flux
that normally passes across axial air gap 238, a path of relatively
high reluctance.
[0022] There is also outer radial air gap 239 between rim portion
273 of armature 270 and housing 230. When solenoid coil 210 is energized,
the magnetic flux of the resulting magnetic field follows a closed
path through magnetic pole piece 220 to end 222, across radial air
gap 235, through ferrule-shaped portion 271 of armature 270, across
outer radial air gap 239, to housing 230, and back to magnetic pole
piece 220. Thus, axial air gap 238 does not effectively contribute
to the magnetic flux path. The result is an effective linearization
of the force versus air gap characteristic over a prescribed range,
irrespective of the relative axial separation between armature 270
and end 222 of magnetic pole piece 220.
[0023] In an alternate embodiment, one or both of radial air gap
235 and outer radial air gap 239 are located within coil bore 211,
which requires a non-magnetic spacer (not shown), which is conventionally
welded to magnetic elements in order to maintain all of the non-magnetic
and magnetic elements in coaxial alignment during the manufacturing
process. A welded tube would then be needed, formed using a magnetic
material on the ends and a non-magnetic tube in the middle. However,
this would require additional construction costs. Locating both
radial air gap 235 and outer radial air gap 239 outside of coil
bore 211 dispenses with the need for a non-magnetic spacer.
[0024] FIG. 3 shows an alternate embodiment of the entire valve
assembly 100 in which most of the same components can be seen. The
embodiment in FIG. 3 includes an alternate embodiment of armature
270 in which armature 270 does not include the ferrule-shaped portion.
As in the embodiment shown in FIGS. 1 and 2, when solenoid coil
210 is energized, the magnetic flux of the resulting magnetic field
follows a closed path through magnetic pole piece 220, across axial
air gap 238, and through rim portion 273 of armature 270, to housing
230, and back to magnetic pole piece 220, completing the magnetic
flux circuit.
[0025] FIG. 4 shows an enlarged embodiment of armature 270 in which
ferrule-shaped portion 271 is tapered. The fact that ferrule-shaped
portion 271 of armature 270 is tapered, or has a varying thickness
in the axial direction, causes this portion of armature 270 become
immediately saturated in the course of its diverting magnetic flux
that would otherwise pass across axial air gap 238, minimizing hysteresis.
Consequently, as in the earlier embodiments described herein, the
magnetic flux through armature 270 is principally confined in the
radial direction, by-passing the substantial reluctance path along
axial air gap 238. This causes the force imparted by solenoid coil
210 on armature 270 to vary in proportion to the applied signal,
so that axial displacement of armature 270 against the bias of biasing
member 260 varies in proportion to the signal. As in the embodiment
shown in FIGS. 1 and 2, when solenoid coil 210 is energized, the
magnetic flux of the resulting magnetic field follows a closed path
through magnetic pole piece 220, across radial air gap 235, through
ferrule-shaped portion 271 of armature 270, jumping outer radial
air gap 239 to housing 230, and finally back again to magnetic pole
piece 220.
[0026] FIG. 5 shows an alternate embodiment of valve assembly 100.
Step-shaped annular ring 206, installed atop interior ledge element
245, can be appreciated and supports magnetic pole piece 220 within
coil bore 211. Step-shaped annular ring 206 is also sized to provide
a cavity from which end 222 of magnetic pole piece 220 protrudes,
and which accommodates axial displacement of ferrule-shaped portion
271 of armature 270.
[0027] Also visible in FIG. 5, the components of one embodiment
of the calibration mechanism can be appreciated. The armature-biasing
axial pin 215 provides an externally calibrated spring bias force
along axis A against armature 270, so as to establish the amount
of force required to axially translate armature 270 away from its
closed position (as shown). Calibration member 295 adjusts the amount
of force that armature-biasing axial pin 215 exerts on armature
270. In order to calibrate the solenoid actuator, namely, calibrate
the amount of force required to axially translate armature 270 along
axis A in a direction towards magnetic pole piece 220, where poppet
332 is urged against valve seat 351 and closing valve unit 300,
a threaded cylindrical shaft member 216 is threaded into an upper
region of pole piece bore 221 of magnetic pole piece 220, and covered
by a protective cap 217. A portion of shaft member 216 is sized
to fit within one end of biasing member 260, which has an opposite
end captured upon a portion of armature-biasing axial pin 215. The
degree to which shaft member 216 is threaded into pole piece bore
221 establishes an axially directed spring-bias against armature
270, and thereby against valve seat 351 by poppet 332. Lock nut
219 may be threaded onto an externally threaded end portion of shaft
member 216 to prevent further rotation of shaft member 216, once
shaft member 216 has been rotated within pole piece bore 221 of
magnetic pole piece 220 to establish the desired valve opening force.
One of ordinary skill in the art will recognize that alternate calibration
mechanisms known in the art can be used to adjust the amount of
force which armature 270 must overcome to axially translate towards
magnetic pole piece 220.
[0028] Magnetic pole piece 220, housing 230, and armature 270 are
made of magnetic iron, but could also be made of any magnetic material
including magnetic steel, silicon-iron alloys, cold-rolled steel,
or any ferro-magnetic material, and each component need not be made
of the same magnetic material within the same valve assembly 100.
[0029] Furthermore, as stated supra, valve assembly 100 need not
include housing 230. If there is no housing, the magnetic flux generated
by solenoid coil 210, when subject to an electric signal, must then
travel through the air around valve assembly 100 to complete the
circuit, and a stronger electric signal is required for proper operation
of valve assembly 100. In an alternate embodiment without a housing,
a "C-frame" (a C-shaped electrical connector) is used
to complete the magnetic flux path.
[0030] Referring again to FIG. 1, valve unit 300 can be viewed.
Within base member 310 of valve unit 300, fluid input port 321 opens
into a first generally cylindrical bore 326. Fluid exit port 322
opens into a second generally cylindrical bore 327. In operation,
with the solenoid actuator calibrated by rotation of shaft member
216 in the manner described supra, fluid flow between fluid input
port 321 and fluid exit port 322 is established by controlling displacement
of poppet 332 relative to valve seat 351, linearly proportional
to the signal supplied to solenoid coil 210. With a fluid supply
coupled to fluid input port 321, translating poppet 332 away from
its closed position against valve seat 351 allows the fluid within
fluid flow chamber 331 to flow through valve seat bore 355 to bore
327 and exit valve assembly 100 via fluid exit port 322. As shown
in FIGS. 1 and 3, chamber 331 is defined by both housing extension
231 (which is mechanically coupled to housing 230 by means known
to those of ordinary skill in the art) and base member 310.
[0031] Referring again to FIG. 1, the embodiment of valve unit
300 depicted therein is comprised of generally cylindrical base
member 310 having fluid input port 321 into which fluid, the flow
rate of which is to be regulated, is introduced, and fluid exit
port 322 from which the fluid exits valve unit 300. Fluid input
port 321 and fluid exit port 322 may be internally threaded, as
shown at internal threadings 311 and 313, respectively, so that
valve unit 300 may be installed between respective sections of fluid
transporting conduit (not shown). One of ordinary skill in the art
will recognize that either fluid input port 321 or fluid exit port
322 could be located along Axis A (i.e., on the bottom surface of
base member 310) as opposed to on the sides of base member 310.
In the embodiment shown in FIG. 1, base member 310 is made of a
non-magnetic material, such as stainless steel, but could also be
made of a magnetic material, such as those provided supra.
[0032] One embodiment of poppet assembly 330 can also be seen in
FIG. 1. FIG. 6 shows an enlarged view of an alternate embodiment
of poppet assembly 330 and valve seat 351. Poppet assembly 330 is
comprised of poppet 332 with lapped surface 333 and poppet cavity
334, poppet balance stem 335 which fits within poppet cavity 334,
and poppet cap 336 which holds poppet balance stem 335 within poppet
cavity 334. The various components of poppet assembly 330 can be
made of magnetic materials, such as those provided supra, or structurally
hard non-magnetic materials. One example of a non-magnetic material
is stainless steel.
[0033] Poppet balance stem 335 has two ends, ball 338 on one end
which fits within poppet cavity 334 and distal end 337 at the other
end. Distal end 337 is configured to be coupled to the armature
(not shown), either directly or via the armature retainer (not shown),
such that when the armature is raised or lowered, the entire poppet
assembly 330 also raises or lowers. One mechanism for attaching
distal end 337 of poppet balance stem 335 to the armature is to
use a threading on distal end 337 and a corresponding threading
on the armature or the armature retainer and screwing it either
directly into the armature or into the armature retainer, which
is directly connected to the armature. Thus, when the solenoid coil
(not shown) is energized, fluid flow between chamber 331 and valve
seat bore 355 is established by controlling displacement of poppet
332 relative to valve seat 351, in linear proportion to the signal
supplied to the solenoid coil. Fluid within chamber 331 is allowed
to pass underneath poppet assembly 330, through valve seat bore
355, and out of valve unit 300 via fluid exit port 322.
[0034] In the embodiment of poppet assembly 330 shown in FIGS.
5 and 6, ball 338 of poppet balance stem 335 has two springs 341,
342 around it when within poppet cavity 334, first spring 341 above
the widest part of ball 338 and second spring 342 below. An example
of first and second springs 341 and 342 are those manufactured by
"Bal-Seal." In alternate embodiments, only first spring
341 or second spring 342 is included.
[0035] Also visible in the embodiment shown in FIGS. 5 and 6, poppet
cavity 334 has conical depression 343 to allow for a better fit
of ball 338 within poppet cavity 334 which also allows potting compound
to essentially completely surround ball 338. One of ordinary skill
in the art will recognize that depression 343 could be a shape other
than conical and that poppet cavity 334 could be of any other shape
capable of containing ball 338.
[0036] As can be seen in the alternate embodiment of poppet assembly
330 of FIG. 6, valve seat 351 is comprised of insert 360, which
rests atop cylindrical lip 354. Insert 360 can be constructed using
any of the materials provided supra for poppet assembly 330. Furthermore,
to prevent the unintentional flow of fluid along the outside of
valve seat 351, i.e., from passing between insert 360 and base member
310, one or more fluid sealing members 358 can be added. In the
embodiment shown in FIG. 6, two fluid sealing members 358 have been
added. In this embodiment, fluid sealing members 358 are O-rings.
However, as can be seen in FIGS. 1, 3, and 5, valve seat 351 can
also be constructed of one piece, contiguous with base member 310,
making the need for insert 360, cylindrical lip 354, and fluid sealing
member(s) 358 unnecessary.
[0037] Whether one piece or two, valve seat 351 of base member
310 projects into chamber 331 to allow a portion of the fluid therein
to be under lapped surface 333, reducing the effect of fluid pressure
on the axial movement of poppet assembly 330.
[0038] In order to have a near perfect fluid seal between poppet
assembly 330 and valve seat 351, poppet 332 mounted via a ball-and-socket
connection which allows lapped surface 333 of poppet 332 to be an
almost perfect alignment with valve seat 351. One method used to
create this custom-fit seating between poppet 332 and valve seat
351 is to employ the following procedure. Generally, the method
involves:
[0039] 1) depositing a potting compound (i.e. any substance that
has a curing time; e.g., Lock-Tite.TM. and epoxy) into poppet cavity
334 of poppet 332, coating the surfaces, and filling it approximately
half way. If poppet 332 has depression 343, care should be taken
to ensure that depression 343 is also filled with the adhesive compound;
[0040] 2) inserting ball 338 into poppet cavity 334 and retaining
it within poppet 332 using poppet cap 336;
[0041] 3) lowering poppet assembly 330 against valve seat 351 so
that lapped surface 333 of poppet 332 is pressed flush against valve
seat 351;
[0042] 4) repeating the lowering step as necessary to ensure that
the seating between lapped surface 333 of poppet 332 and valve seat
351 is near perfect; and
[0043] 5) allowing the adhesive compound to cure so that poppet
332 can no longer pivot around ball 338.
[0044] This results in a custom-fitted poppet for that specific
valve, i.e., a "self-leveled poppet." The effect is a
custom-tailored and near perfectly matched poppet assembly 330 for
valve seat 351, in which poppet 332 is almost perfectly flush with
valve seat 351.
[0045] There are many alterations of this method that one of ordinary
skill will recognize; nor is the numbering intended to indicate
that the steps must be performed in any particular order. By way
of example and not intended to be limiting, ball 338 could be inserted
into poppet cavity 334 before the potting compound, though it will
be more difficult to ensure that the bottom of ball 338 is cemented
and that depression 343 is filled with potting compound. Furthermore,
depending on the size of the hole in poppet cap 336, the threaded
end of poppet balance stem 335 may have to be inserted through the
hole in poppet cap 336 before inserting ball 338 into poppet cavity
334.
[0046] Although, for convenience, the invention has been described
primarily with reference to several specific embodiments, it will
be apparent to those of ordinary skill in the art that the valve
and the components thereof can be modified without departing from
the spirit and scope of the invention as claimed. |