U.S. patent number RE40,051 [Application Number 10/803,197] was granted by the patent office on 2008-02-12 for one-piece self-venting drain valve.
This patent grant is currently assigned to Wix Filtration Corp LLC. Invention is credited to Mark A. Roll, Willie L. Stamey, Jr..
United States Patent |
RE40,051 |
Stamey, Jr. , et
al. |
February 12, 2008 |
**Please see images for:
( Certificate of Correction ) ** |
One-piece self-venting drain valve
Abstract
A self-venting drain valve is rotatably and slidably mounted to
a filter assembly through an internally threaded base. The drain
valve comprises a homogenously formed one-piece unitary valve body
including a tubular valve stem portion and a valve knob portion.
The valve stem portion includes a wall member defining an internal
passageway provided with axially extending air vent openings
through which ambient air can enter a filter housing through the
internal passageway, and drain holes through which water is drained
from the filter housing and the internal passageway. The air vent
openings are formed through an upper portion of the wall member and
are open to a top edge thereof, while the drain holes are formed
through the lower portion of the wall member. The liquid drains
from the filter housing through the internal passageway and the
drain holes, then exits into the valve knob portion.
Inventors: |
Stamey, Jr.; Willie L. (Kings
Mountain, NC), Roll; Mark A. (Bessemer City, NC) |
Assignee: |
Wix Filtration Corp LLC
(Gastonia, NC)
|
Family
ID: |
22464526 |
Appl.
No.: |
10/803,197 |
Filed: |
March 18, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
10134693 |
Apr 30, 2002 |
06565746 |
May 20, 2003 |
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Current U.S.
Class: |
210/248; 137/588;
210/313; 210/541 |
Current CPC
Class: |
B01D
27/08 (20130101); B01D 36/006 (20130101); B01D
2201/4084 (20130101); Y10T 137/86332 (20150401) |
Current International
Class: |
F16K
24/00 (20060101); B01D 35/00 (20060101) |
Field of
Search: |
;210/248,313,541
;137/588 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lithgow; Thomas M.
Attorney, Agent or Firm: Honigman Miller Schwartz Cohn
LLP
Claims
What is claimed is:
1. A self-venting drain valve for draining a contaminant liquid
from a filter housing of a filter assembly, said filter housing
having a valve receiving bore through which said liquid may drain
and gas may simultaneously enter said filter housing, said valve
comprising: an integral valve body for selectively permitting and
preventing draining said contaminant liquid from said filter
housing through said bore; said valve body having a substantially
tubular stem portion positioned in said valve receiving bore within
said filter housing, said tubular stem portion including a
substantially tubular wall member defining in internal passageway
and having at least one drain hole therethrough and at least one
air vent opening therethrough both adapted to fluidly communicate
said internal passageway to an ambient air; said valve body being
selectively positionable within said bore between a closed position
wherein said at least one drain hole is sealed for preventing the
liquid and air movement through said bore and an open position
wherein said at least one drain hole is unsealed and said at least
one air vent opening is partially open to said ambient air for
allowing both liquid and air movement along said internal
passageway within said tubular stem portion of said valve body.
2. The self-venting drain valve as defined in claim 1, wherein said
integral valve body further includes a knob portion positioned
outside said filter housing and juxtaposed to a lower end of said
valve stem portion, said knob portion provided for manually
manipulating said self-venting drain valve.
3. The self-venting drain valve as defined in claim 2, wherein said
knob portion of said valve body is provided with a drain reservoir
to assist the drainage of said liquid from said filter housing by
accumulating said draining liquid exiting said at least one drain
hole in said stem portion of said valve body to maintain a constant
liquid head and controlled flow resistance.
4. The self-venting drain valve as defined in claim 3, wherein said
drain reservoir is substantially annular in shape.
5. The self-venting drain valve as defined in claim 3, wherein said
knob portion further including a drain spout adapted to assist the
drainage of said liquid from said drain reservoir and allow a user
to connect a hose to drain said liquid without spillage.
6. The self-venting drain valve as defined in claim 2, wherein an
outer peripheral surface of said knob portion further including a
wrench socket adapted to receive a wrench for rotatably driving
said valve body between said closed position and said open
position.
7. The self-venting drain valve as defined in claim 2, wherein said
valve body including said tubular stem portion and said knob
portion is homogenously formed as a one-piece unitary member.
8. The self-venting drain valve as defined in claim 7, wherein said
valve body is made of a plastic material.
9. The self-venting drain valve as defined in claim 8, wherein said
valve body is manufactured by an injection molding process.
10. The self-venting drain valve as defined in claim 1, wherein an
upper portion of said at least one air vent opening remains within
said filter housing while said valve body is in said open
position.
11. The self-venting drain valve as defined in claim 1, wherein
said at least one air vent opening is disposed above said at least
one drain hole.
12. The self-venting drain valve as defined in claim 1, including
two air vent openings formed through tubular wall member of said
valve body and two opposite drain holes formed therethrough.
13. The self-venting drain valve as defined in claim 1, wherein a
lower end of said tubular wall member comprises external threads
that threadedly secure said valve body in said closed position.
14. The self-venting drain valve as defined in claim 13, wherein
said valve receiving bore comprises internal threads adapted to
engage said external threads on said lower ends of said wall member
to hold said valve body in said closed positions.
15. The self-venting drain valve as defined in claim 1, wherein an
upper end of said tubular wall member comprises at least one
cantilever snap arm adapted to engage said valve receiving bore for
retaining said valve body in said open position.
16. The self-venting drain valve as defined in claim 15, wherein
said at least one air vent opening is defined by an axially
extending space provided between said tubular wall member and said
snap arm.
17. The self-venting drain valve as defined in claim 16, wherein
said axially extending space defining said at least one air vent
opening is open to a top edge of said wall member of said stem
portion of said valve body.
18. The self-venting drain valve as defined in claim 1, further
comprising a gasket positioned around said lower end of said valve
stem portion to seal said internal passageway when said drain valve
is in said closed position.
19. The self-venting drain valve as defined in claim 2, wherein a
generally cylindrical outer peripheral surface of said knob portion
is provided with axially oriented ribs to facilitate manual
gripping of said knob portion of said valve body.
20. A self-venting drain valve for draining a contaminant liquid
from a filter housing of a filter assembly, said filter housing
having an internally threaded valve receiving bore through which
said liquid may drain and gas may simultaneously enter said filter
housing, said valve comprising: an integral valve body for
selectively permitting and preventing draining said contaminant
liquid from said Filter housing through said bore; said valve body
having a tubular stem portion positioned in said valve receiving
bore within said filter housing and a knob portion positioned
outside said filter housing and juxtaposed to a lower end of said
valve stem portion for manually manipulating said self-venting
drain valve; said tubular stem portion including a substantially
tubular wall member defining an internal passageway and having two
opposite drain holes therethrough formed in a lower end thereof,
two opposite cantilever snap arms formed in an upper end of said
tubular wall member and two opposite air vent openings therethrough
defined by axially extending spaces provided between said tubular
wall member and said snap arms, said drain holes and said air vent
openings adapted to fluidly communicate said internal passageway to
an ambient air, said air vent openings are disposed above said
drain holes; said knob portion of said valve body is provided with
a substantially annular drain reservoir to assist the drainage of
said liquid from said filter housing by accumulating said liquid
exiting said drain holes in said stem portion of said valve body to
maintain a constant liquid head and controlled flow resistance and
a drain spout adapted to assist the drainage of said liquid from
said drain reservoir and allow a user to connect a hose to drain
said liquid without spillage; said valve body being selectively
positionable within said bore between a closed position wherein
said drain holes are sealed for preventing said liquid and air
movement through said bore and an open position wherein said drain
holes are unsealed and said at least one air vent opening is
partially open to said ambient air for allowing both liquid and air
movement along said internal passageway within said tubular stem
portion of said valve body; a lower end of said tubular wall member
comprises external threads adapted to engage said threaded valve
receiving bore for securing said valve body in said closed
position; said cantilever step arms are adapted to engage said
threaded valve receiving bore for retaining said valve body in said
open position; an outer peripheral surface of said knob portion
further including a wrench socket adapted to receive a wrench for
rotatably driving said valve body between said closed position and
said open position; wherein said valve body including said tubular
stem portion and said knob portion is homogenously formed as a
single piece unitary member of a plastic material by an injection
molding process.
.Iadd.21. A self-venting drain valve for draining a contaminant
liquid from a filter housing of a filter assembly, said filter
housing having a valve receiving bore through which said liquid may
drain and gas may simultaneously enter said filter housing, said
valve comprising: an integral valve body for selectively permitting
and preventing draining said contaminant liquid from said filter
housing through said bore; said valve body having a substantially
tubular stem portion positioned in said valve receiving bore within
said filter housing, said tubular stem portion including a
substantially tubular wall member defining an internal passageway
and having at least one drain hole therethrough and at least one
air vent opening therethrough both adapted to fluidly communicate
said internal passageway to an ambient air; said valve body being
selectively positionable within said bore between a closed position
wherein said at least one drain hole is sealed for preventing the
liquid and air movement through said bore and an open position
wherein said at least one drain hole is unsealed and said at least
one air vent opening is open to said ambient air for following both
liquid and air movement along said internal passageway within said
tubular stem portion of said valve body..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to self-venting valves, and more
particularly to a self-venting valve for draining water from fuel
filter assemblies.
2. Description of the Prior Art
Self-venting liquid drain valves have been known in the art for
many years. Specifically, various assemblies have been made to
provide fluid drainage from a vessel while providing a separate
inlet for gas, such as air, to replace the fluid being drained. For
example, in fuel/water separators used in diesel engines, water
must be periodically drained using a valve assembly adapted to feed
air into a separator while the water is being drained. The prior
art devices have accomplished this by providing separate air and
liquid passages formed through a portion of the valve assembly
member.
A problem that occurs with fluid filter assemblies, particularly
useful for diesel engines and gasoline marine engines, is
facilitating the removal of contaminants from the filter assembly.
These contaminants include water and particulate matter that tend
to settle at the bottom of housings used to retain filter elements.
In order to remove the water and particulate matter suspended in
the water, drain valves are frequently positioned at the bottom of
housings used to retain filter elements. If a simple drain cock is
utilized for the valve, the drainage may not be complete or may not
occur at all because a partial vacuum is created in the filter
housing upon initiating drainage. The partial vacuum prevents water
from flowing through the open valve.
In order to facilitate drainage by breaking the partial vacuum,
drainage valves in fuel filters are vented. It is necessary to
close the vent hole when the valves are closed so that fluid within
the fluid filter does not flow out through the vent hole. In prior
art arrangements there is the possibility of vent holes becoming
blocked by particulate debris suspended in the fuel or water at the
bottom of the housing. This is because the end of the vent tube,
which opens within the housing, is left continuously open so that
over time particles can accumulate in the vent tube.
Furthermore, currently used drain valves are made of multiple parts
that makes them expensive in manufacturing and laborious and
difficult to assemble.
SUMMARY OF THE INVENTION
The present invention provides a new and improved self-venting
drain valve for filter assemblies and the like, which self-venting
valve is reliable and is configured for ease of assembly and
operation. The self-venting drain valve is provided for selectively
permitting and preventing draining of contaminant liquid, such as
water, from a housing of the filter assembly, such as a fuel filter
assembly.
The self-venting drain valve in accordance with the preferred
embodiment of the present invention includes a one-piece unitary
valve body slidably received within a valve retaining bore in the
filter housing between a closed position preventing draining of
contaminant liquid and an open position permitting draining of
contaminant liquid. The homogenously formed one-piece unitary valve
body comprises a valve stem portion positioned in the valve
receiving bore within the filter housing, and a valve knob portion
disposed at a lower portion of the valve stem portion and
positioned outside the filter housing.
The valve stem portion includes a substantially tubular wall member
defining an internal passageway provided with at least one drain
hole through which water is drained from the filter housing and the
internal passageway, at least one cantilever snap arm formed in an
upper end of the tubular wall member and at least one air vent
opening therethrough defined by an axially extending space provided
between the tubular wall member and the snap arm and through which
ambient air can enter a filter housing through the internal
passageway. Both the drain hole and the air vent opening are
adapted to fluidly communicate the internal passageway to an
ambient air.
The air vent opening is formed through an upper end of the wall
member and is open to a top edge thereof, while the drain hole is
formed through the lower portion of the wall member. Thus, the
entry of air into the housing of the filter assembly as allowed by
the air vent openings is above the drain holes in order to
facilitate drainage of the filter housing as proper siphoning of
water has been found to be assisted. It has been also found that
the drain holes of the water outlet should open slightly before the
air vent openings of the air inlet opens to provide the proper flow
sequencing. This function is achieved by locating the air vent
openings well above the drain holes into the wall member of the
valve stem portion.
Preferably, the valve body comprises two opposite drain holes and
two opposite cantilever snap arms and, respectively, two opposite
air vent openings.
Moreover, the lower portion of the wall member is provided with
external threads which threadedly mate and are received within the
internally threaded base of the filter housing. The external
threads engage the internally threaded base when the drain valve is
in the closed position. When the drain valve is in the open
position, the snap arms formed at the upper end of the wall member
engages the threaded base of the filter housing to secure open the
drain valve.
The valve knob portion is adapted to facilitate manual operation of
the drain valve and to assist in draining water from the filter
housing. The valve knob portion includes a substantially annular
groove facing the valve stem portion and defining a drain
reservoir, and a drain spout forming a drain passageway through
which the water drains. The liquid drains from the filter housing
through the internal passageway and the drain holes, then into the
drain reservoir in the valve knob portion, and exits the valve
through the drain spout.
Preferably, the valve body of the self-venting drain valve
including the tubular stem portion and the knob portion is
homogenously formed as a one-piece unitary member and is made of a
plastic material by an injection molding process.
Therefore, the one-piece self-venting drain valve in accordance
with the present invention provides a simple self-venting liquid
drain valve permitting liquid such as water to drain while gas such
as ambient air enters the vessel being drained to facilitate
drainage, even when the filter housing is subjected to a vacuum.
The self-venting drain valve of the present invention is relatively
simple and inexpensive to manufacture because of the simplicity of
its design that is a significant improvement over prior art
valves.
Upon further study of the specification and appended claims,
further features and advantages of this invention will become
apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent
from a study of the following specification when viewed in light of
the accompanying drawings, wherein:
FIG. 1 is a cross-sectional view of a filter assembly;
FIG. 2 is a cross-sectional view of a filter assembly in
combination with a self-venting drain valve of the present
invention in a closed position;
FIG. 3 is a cross-sectional view of the filter assembly in
combination with the self-venting drain valve of the present
invention in an open position;
FIG. 4 is a perspective view of the self-venting drain valve of the
present invention;
FIG. 5 is a cross-sectional view of the self-venting drain valve of
the present invention;
FIG. 6 is a bottom view of the self-venting drain valve of the
present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The preferred embodiment of the present invention will now be
described with the reference to accompanying drawings.
Referring now mainly to FIGS. 1, 2 and 3, a filter assembly 10, to
which the present invention can be applied, includes a housing 12
in which is disposed a filter element 14 that is biased by a coil
spring 18 to seat against an end cap 20. In operation illustrated
in FIG. 2, fuel to be filtered, represented by arrows 21, enters
the housing 12 through a plurality of inlets 22 flows outside of
the filter element 14 and through the filter element 14 into a
hollow core 24. The fuel 21 then flows out of end plate 20 through
threaded outlet 26 and is delivered to an engine such as a diesel
or other internal combustion engine.
The filter element 14 separates water 27 from the fuel 21 as the
fuel passes through the filter and the water pools in a space 28 at
the bottom of the housing 12. Solid particulate contaminants 30,
which have been filtered out by the filter element 14, also tend to
fall out of the fuel 21 and water 27 and accumulate in the space 28
in the bottom of the housing 12.
As illustrated in details in FIG. 1, disposed in an end opening 36
that is coaxial with the axis 38 of the fuel filter assembly 10 is
an internally threaded base 40 having an internal thread 42
defining a valve receiving bore. The base 40 has a shelf 44 against
which one end of the coil spring 18 bears, the other end of the
coil spring bearing against the filter element 14 to hold the
filter element in engagement with the plate 20 at an area 48
surrounding the outlet 26.
During operation of the filter assembly 10 as illustrated in FIG.
3, the water 27 accumulates in the bottom portion of the housing 12
thereof and must be drained periodically to permit continued
satisfactory operation of the filter assembly 10. In order to drain
the water 27, which has accumulated in the space 28 of the housing
12, a self-venting drain valve 50 is threadedly received through
the valve receiving bore 42 in the base 40. To perform this
function, the valve 50 provides a drain path through which water
collected in the bottom portion of the housing 12 may be drained
out of the housing 12 while providing a passage for air to enter
the housing 12 simultaneously to break the vacuum within the
housing 12 and facilitate drainage. As is seen in FIG. 2, when the
valve is closed, liquid in the housing 12 cannot drain from the
filter assembly. As is seen in FIG. 3, when self-venting the drain
valve 50 is open, water 27 flows in the path of arrow 51 through
the drain valve 50 while air follows the path of arrow 53 into the
housing 12 to prevent a partial vacuum from occurring therein which
would interfere with the flow of water out of the drain valve 50.
Since water is heavier than fuel 21, water 27 accumulates in the
space 28 while fuel remains above the top surface of the water. The
drain valve 50 is held in the FIG. 3 position until the person
draining water 27 from the filter assembly 10 detects only fuel 21
draining therefrom. As will be explained more fully below, the
drain valve 50 described herein provides a self-venting feature by
a structure that is comparatively simple and inexpensive to
manufacture as compared to the prior art designs.
The self-venting drain valve 50 in accordance with the preferred
embodiment of the present invention, illustrated in detail in FIGS.
4 and 5, comprises a homogenously formed one-piece unitary valve
body 52, preferably made of relatively lightweight and low-cost
synthetic plastic materials that will not be corroded when exposed
to the water flowing therethrough, such as rigid polyvinyl chloride
(PVC). Preferably, the one-piece unitary valve body 52 is
manufactured by injection molding. Alternatively, non-plastic
corrosion-resistant materials, such as stainless steel or aluminum,
may be used for manufacturing the one-piece valve body 52 of the
drain valve 50. The one-piece unitary valve body 52 comprises a
valve stem portion 54 and a valve knob portion 56 juxtaposed to a
lower end of the valve stem portion 54.
The self-venting drain valve 50 is rotatably and slidably mounted
to the filter housing 12 by the threaded base 40. In use, the drain
valve 50 is movable between a closed position shown in FIG. 2, and
an open position shown in FIG. 3, with the valve stem portion 54
extending through an opening in the threaded base 40 and the valve
knob portion 56 positioned outside the filter housing 12.
The valve stem portion 54 is generally cylindrical in shape and
includes a substantially tubular wall member 55 defining an
internal passageway 58 through which liquid such as water may drain
from the housing 12 of the filter assembly 10 and ambient air may
enter the filter housing 12, and at least one drain hole 62 through
which water is drained from the filter housing 12 and the internal
passageway 58. Preferably, the valve stem portion 54 of the valve
body 52 includes two opposite drain holes 62. The valve stem
portion 54 further includes two opposite cantilever snap arms 66
adapted to retain the valve body 52 within the threaded base 40 in
the open position. The snap arms 66 are preferably formed at the
upper end of the wall member 55 integrally with the wall member 55.
As shown in FIGS. 4 and 5, an axially extending space 60 is
provided between the wall member 55 and the snap arms 66. The space
60 defines an air vent opening through which ambient air can enter
the filter housing 12 via the internal passageway 58. The air vent
openings 60 are formed through an upper end of the wall member 55
and are open to a top edge 55' thereof, while the drain holes 62
are formed through the lower portion of the wall member 55. It will
be appreciated that any appropriate number of the snap arms, the
air vent openings and drain holes, one, three, etc., is within the
scope of the present invention.
Moreover, the lower portion of the wall member 55 is provided with
external threads 64 which threadedly mate and are received within
the internal threaded base 40 of the filter housing 12. The
external threads 64 engage the internally threaded base 40 as shown
in FIG. 2 when the drain valve 50 is in the closed position. When
the drain valve 50 is in the open position, as shown in FIG. 3, the
cantilever snap arms 66 formed at the upper end of the wall member
55 engage the threaded base 40 of the filter housing 12 to secure
open the drain valve 50. Alternatively, the upper end of the wall
member 55 may be provided with more than one external thread.
As illustrated in detail in FIG. 5, the entry of air into the
housing 12 of the filter assembly 10 as allowed by the air vent
openings 60 is substantially above the drain holes 62 in order to
facilitate drainage of the filter housing 12 as proper siphoning of
water has been found to be assisted. It has been also found that
the drain holes 62 of the water outlet should open slightly before
the air vent openings 60 of the air inlet opens to provide the
proper flow sequencing. This function is achieved by terminating
lower ends of the air vent openings 60 well above openings of the
drain holes 62 into the wall member 55 of the valve stem portion
54.
The valve-knob portion 56 is disposed at the lower portion of the
valve stem portion 54 to facilitate manual operation and to assist
in draining water as will be discussed below. The valve knob
portion 56 includes a substantially annular groove 68 facing the
valve stem portion 54 and defining a drain reservoir 69, and a
drain spout 70 forming a drain passageway 72 through which the
water drains. The drain passageway 72 is open to the drain
reservoir 69 at an upper end thereof, and to the ambient atmosphere
at a lower end thereof. The drain spout 70 allows connection of a
hose to drain fluid into a container without spillage.
Additionally, the drain reservoir 69 allows to accumulate liquid
being drained and also collects any liquid which may leak through a
space between the valve stem portion 54 and the threaded base
40.
Moreover, the knob portion 56 includes a wrench socket 74 formed at
a bottom surface 73 thereof and adapted to receive a wrench (not
shown) for rotatably driving the valve body 52 between the closed
position and the open position. As best illustrated in FIG. 6, the
wrench socket 74 has generally square shape adapted to receive a
standard 1/2 inch wrench (not shown). However, it will be
appreciated by those skilled in the art that the wrench socket 74
may be of any appropriate shape, such as hexagonal.
Furthermore, a generally cylindrical outer peripheral surface 76 of
the knob portion 56 is provided with axially oriented ribs 78 to
facilitate manual gripping of the knob portion 56 of the valve body
52.
A gasket 63 disposed around the lower and of the valve stem portion
54 is trapped between a chamfered sealing surface 46 the threaded
base 40 and the valve knob portion 56 when the drain valve 50 is in
its closed position as shown in FIG. 2, in order to seal the
internal passageway 58. The gasket 63 effectively seals both the
air inlet and the water outlet when the drain valve 50 is in its
closed position because the air vent openings 60 and the drain
holes 62 are inside the filter housing 12. The gasket 63 is the
only gasket required. Preferably, the gasket 63 is in the form of a
conventional O-ring made of any appropriate elastic material, such
as rubber.
To drain fluid from the filter housing 12, when valve assembly 50
is in the closed position as shown in FIG. 2, the valve assembly 50
is unscrewed so that the external threads 64 no longer mate with
the internally threaded base 40. The unthreaded central portion of
the valve stem portion 54 drops down through an aperture in the
threaded base 40 of the filter housing 12, until the snap arms 66
engage the threaded base 40 to retain the valve assembly 50 in the
open position, as shown in FIG. 3. At this point, liquid such as
water in the filter housing 12 begins to siphon out of the filter
housing 12 through the internal passageway 58 and the drain holes
62, while ambient air enters the filter housing 12 through the air
vent openings 60 and the internal passageway 58. Water is siphoned
through the passageway 58 because the drain holes 62 in the lower
end of the valve stem portion 54 are disposed lower than the air
vent openings 60 disposed at the upper end of the valve stem
portion 54. After water exits the internal passage 58 through the
drain holes 62, it fills the drain reservoir 69 in the valve knob
portion 56, then drains through the drain passageway 72 in the
drain spout 70.
Therefore, the one-piece self-venting drain valve in accordance
with the present invention provides a simple self-venting liquid
drain valve permitting liquid such as water to drain while gas such
as ambient air enters the vessel being drained to facilitate
drainage, even when the filter housing is subjected to a vacuum.
The air enters the filter housing through the same fluid path in
the valve assembly the draining water exits the filter housing. The
self-venting drain valve of the present invention is relatively
simple and inexpensive to manufacture because of the simplicity of
its design that is a significant improvement over prior art
valves.
The foregoing description of the preferred embodiments of the
present invention has been presented for the purpose of
illustration in accordance with the provision of the Patent
Statutes. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed. Obvious modifications or
variations are possible in light of the above teachings. The
embodiments disclosed hereinabove were chosen in order to best
illustrate the principles of the present invention and its
practical application to thereby enable those of ordinary skill in
the art to best utilize the invention in various embodiments and
with various modifications as are suited to the particular use
contemplated, as long as the principles described herein are
followed. Thus, changes can be made in the above-described
invention without departing from the intent and scope thereof. It
is also intended that the scope of the present invention be defined
by the claims appended thereto.
* * * * *