Title: Integral check valve for nozzles
Abstract: A check valve for use in a section of a liquid flow line to control the intermittent flow of a liquid through the line, wherein the section of the line that is configured to received the valve has inlet and outlet ends with an opening through which liquid respectively enters or exits the section, includes a compression spring having upstream and downstream ends, wherein the spring is configured so as to allow the downstream end to press against the section outlet end. This check valve further includes a piston having bottom, top and outer side surfaces, with this piston having a cavity that extends from its top surface and is configured to allow the spring to sit and operated freely within the cavity with the spring's upstream end resting on the bottom surface of the cavity. This piston also has an opening in its side surface that connects the cavity and its outer side surface, and the piston's bottom surface has a raised sealing surface with an outer boundary that is configured so as to allow the boundary to enclose the opening in the section's inlet end. This check valve operates by having its piston's bottom surface press against the section inlet end due to the action of the spring so as to seal around the opening of the inlet end. The piston is made from an elastomeric material so as to give the piston the elastic properties necessary to allow its bottom surface to act as a seal for the inlet opening.
Patent Number: 6,948,513 Issued on 09/27/2005 to Steerman, et al.
| Inventors:
|
Steerman; Daniel E. (Harpers Ferry, WV);
Clough; Melvyn J. L. (Columbia, MD)
|
| Assignee:
|
Bowles Fluidics Corporation (Columbia, MD)
|
| Appl. No.:
|
461266 |
| Filed:
|
June 16, 2003 |
| Current U.S. Class: |
137/15.18; 137/315.33; 137/540; 239/284.1; 239/571 |
| Intern'l Class: |
F16K 015/02; B60S 001/52 |
| Field of Search: |
137/54321,151.8,315.27,315.33,538,540,543.17
239/284.1,570
|
References Cited [Referenced By]
U.S. Patent Documents
| 3025874 | Mar., 1962 | Yocum.
| |
| 3027913 | Apr., 1962 | Chatham et al.
| |
| 3245429 | Apr., 1966 | Bacino et al.
| |
| 3580275 | May., 1971 | Hanson et al.
| |
| 4350179 | Sep., 1982 | Bunn et al.
| |
| 4590962 | May., 1986 | Tespa.
| |
| 4766930 | Aug., 1988 | Patti.
| |
| 5183075 | Feb., 1993 | Stein.
| |
| 5329949 | Jul., 1994 | Moncourtois et al.
| |
| 5636794 | Jun., 1997 | Hess et al.
| |
Primary Examiner: Krishnamurthy; Ramesh
Attorney, Agent or Firm: Guffey; Larry J.
Claims
1. A check valve for use in a section of a liquid flow pipe to control the flow
of a liquid through said pipe, wherein said section having inlet and outlet ends
with each having an opening through which liquid respectively enters and exits
said section, said check valve comprising:
a compression spring having upstream and downstream ends, wherein said spring
configured so as to allow said downstream end to press against a portion of said
section outlet end,
a piston having bottom, top and outer side surfaces, said piston having a cavity
that extends from said top surface and is configured to allow said spring to sit
and be compressed longitudinally within said cavity with said spring upstream end
resting on a portion of the bottom surface of said cavity, said piston having an
opening in said side surface that connects said cavity and said outer side surface,
said piston bottom surface having a sealing surface protecting outwardly therefrom
with an outer boundary that is configured so as to allow said boundary to enclose
said opening in said section inlet end,
whereby when said piston bottom surface is pressed against said section inlet
end by the action of said spring, said sealing surface seals the area around the
opening of said inlet end so as to prevent liquid from flowing through said opening,
wherein said piston being made from an elastomeric material so as to give said
piston sealing surface the elastic properties necessary to allow said piston bottom
surface to act as a seal for said inlet opening, and wherein said sealing surface
is not a separate member that is inserted into said check valve.
2. A check valve as recited in claim 1, wherein the shape of said sealing surface
is chosen from the group consisting of an O-ring shaped surface or a surface in
the form of an outwardly directed rib having an end that angles upward and away
from said piston bottom surface.
3. A check valve as recited in claim 1, wherein said flow pipe to receive said
valve is the inlet flow passage of the housing for a windshield washer nozzle assembly.
4. A check valve as recited in claim 2, wherein said flow pipe to receive said
valve is the inlet flow passage of the housing for a windshield washer nozzle assembly.
5. A method of making a check valve for use in a section of a liquid flow line
to control the intermittent flow of a liquid through the line, wherein said section
having inlet and outlet ends with each having an opening through which liquid respectively
enters and exits said section, said method comprising the steps of:
acquiring a compression spring having upstream and downstream ends, wherein said
spring configured so as to allow said downstream end to press against said section
outlet end,
acquiring a piston made from an elastomeric material and having bottom, top and
outer side surfaces, said piston having a cavity that extends from said top surface
and is configured to allow said spring to sit and operated freely within said cavity
with said spring upstream end resting on the bottom surface of said cavity, said
piston having an opening in said side surface that connects said cavity and said
outer side surface, said piston bottom surface protecting outwardly therefrom having
a sealing surface with an outer boundary that is configured so as to allow said
boundary to enclose said opening in said section inlet end,
placing said upstream end of said spring in said cavity of said piston,
orienting said valve within said flow line so that the downstream end of said
spring presses against said section outlet and compressing said spring so as to
cause said piston bottom surface to press against said section inlet end so that
said sealing surface seals the area around the opening of said inlet end so as
to prevent liquid from flowing through said opening, and wherein said sealing surface
is not a separate member that is inserted into said check valve.
6. A method as recited in claim 5, wherein said flow line to receive said valve
is the inlet flow passage of the housing for a windshield washer nozzle assembly.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to fluid handling apparatus. More particularly, this
invention relates to an integral check valve of the type that are used in windshield/glass
washer nozzles.
2. Description of the Related Art
Windshield washer spray systems are well known in the art. Generally,
they consist of windshield washer nozzles that are mounted in the hood of a vehicle.
Fluidic inserts in these nozzles cause a jet of windshield washer fluid to be oscillated
laterally so as to project a fan spray of windshield washer droplets that impinge
over the whole lateral width of a windshield.
Check valves are typically included in the washer fluid feed lines of these
nozzles to eliminate "drool" due to: (a) dynamic loads on the windshield washer
system when the car is moving, and (b) static loads on the hood-mounted system
when the car is stationary, but its hood is lifted.
These check valve are designed so as to have a threshold or cracking pressure
below which no fluid will flow through the nozzle. Moreover, such check valves
prevent air from entering the system through the nozzle, which thereby prevents
fluid from draining back into the reservoir for the washer fluid. This permits
a faster response time since the response time is not slowed due to the nozzle's
feed tubes draining back into the reservoir after the system has been actuated.
With the feed tubes remaining "primed," the response time of these nozzles is very
fast. Finally, the relatively high cracking pressure of these nozzles provides
a "crisp start-up and shut-off" which means that the number of drops from such
nozzles that land on surfaces other than the glass at which they are directed is
very small.
For such windshield washer applications, a washer nozzle typically includes a
housing which is welded to an elbow or hose nipple after assembling the check valve
components inside the elbow. The initial designs for washer nozzles were based
on "ball and spring," or soft seat systems.
An example of such a Bowles Fluidics Corporation system that was commercially
used for many years is given in FIG. 1 from U.S. Pat. No. 5,636,794 to Hess and
Marsden. It is seen to comprise a molded housing
10 having a fluidic oscillator
insert chamber
11 adapted to receive a molded silhouette member
12
which has a fluidic oscillator silhouette molded in face
13 and peripheral
side and edge surfaces which are adapted to make a scaling engagement with the
interior walls
14 of chamber
11. The fluidic oscillator has a power
nozzle PN which is adapted to be aligned with the wash fluid inlet passage
15.
Wash fluid inlet passage
15 is coupled to a second wash fluid inlet passage
16. In the embodiment shown, the oscillator chamber
11, inlet passage
15 and inlet passage
16 are made in the molding process by pins which
are withdrawn to leave the passages. A ball
17 is forcibly inserted into
the enlarged end
18 of wash fluid passage
15 to seal it.
The portions
19,
20 are designed to accommodate a particular opening
in the hood or other mounting structure of a vehicle for mounting purposes and
is not particularly relevant to the present invention.
As shown in FIG. 1, the second wash fluid passage
16 is formed in a nipple
21 which has an annular rib
22 molded therein. A check valve assembly
23 is included in a hose nipple
24. The check valve assembly
23
includes an annular shoulder
25 formed on an inward portion of inlet nipple
21 and includes a spring
26 urging ball valve element
27 into
a valve seat
28 formed on the interior wall of wash fluid inlet passage
29. Check valve assembly
23 is assembled by placing the spring on
the shoulder
25 and fitting the ball
28 into the seat and then forcing
the annular connection collar
30 onto the nipple
21 with annular
rib
22 seated in annular groove
31.
It will be appreciated that the design of FIG. 1 is, in effect, a two-piece nozzle
housing where the two pieces are welded or glued together along the nipple
21
and the connection collar
30. That is, the line "L" where the two parts
are joined together can leak and this also requires an extra assembly process.
The "ball and spring" check valves were found to suffer from several problems.
These included: (a) poor sealing between the hard metal surface and hard plastic
surfaces, (b) material corrosion in the contact area, which may lead to a stuck
check valve, (c) cocking of the spring assembly in the housing which causes operational
problems with the valves, (d) cumbersome manual assembly, (e) poor weld strength
in joint linking the housing and the elbow due to the thin wall thicknesses and
structural discontinuities in this area, and (f) difficulty in molding the complex
plastic parts which comprise the housing and elbow.
This "ball and spring" check valve was improved upon by the introduction of
the check valve shown in FIGS.
2-
3(
a)-(
b) which are
also from U.S. Pat. No. 5,636,794. In this check valve, the wash fluid feed tube
50 has an internal shoulder
51 which is deep within wash fluid input
tube
50 for receiving the base of check valve spring
26′.
A ball check valve
28′ is urged or biased by spring
26′
into engagement with valve seat
53 formed on the downstream end of tubular
insert member
54 which has an external surface
55 having a diameter
D at least sufficient to form an elongated wash fluid seal
56 with the annular
walls
57 defining the wash fluid flow path. The tubular insert
54
can be adjusted in length LI (or its depth of insertion adjusted) to thereby adjust
the cracking pressure e.g., the pressure when the valve unseats and wash fluid
is allowed to flow to the windshield washer nozzle. Thus, by adjusting the length
LI of tubular insert
54, the cracking pressure can be adjusted without any
other structural change in the assembly.
For this check valve, the hose or rubber tube
60 is telescoped over the
outer end of input tube
54 and is retained in place by barb
61. The
rubber hose
60 seals along the external surface and is the only seal that
is required thereby eliminating seals such as the seal between the coupling element
30 and nipple
21 of the prior art design shown in FIG.
1.
FIGS.
3(
a)-(
b) disclose other embodiments in which the
shape of the check valve element is other then that of a ball. In FIG.
3(
a),
the check valve
66 has a conical external surface and a centering projection
65 on its downstream end. In FIG.
3(
b), the check valve
75
has a rounded, mushroom-shape external surface and a centering projection
65
on its downstream end.
A further improvement to these types of check valves at Bowles Fluidics has been
the replacement of these ball and other types of check valves with a "carrier assembly,"
consisting of a piston and seal, such as that shown in FIG.
4(
a).
More details of these piston and seal elements are shown in FIGS.
4(
b)-(
c).
However, this configuration has been found to be cumbersome to manually assembly,
and is not a manufacturing friendly design. Additionally, welding and molding of
these parts has continued to be a problem.
Thus, despite the prior art, there still exists a continuing need for improvements
in the design of check valves for a wide range of nozzle applications.
3. Objects and Advantages
Recognizing the need for the development of improved check valves, the
present invention is generally directed to satisfying the needs set forth above
and overcoming the disadvantages identified with prior art devices.
It is an object of the present invention to provide an improved check valve for
a windshield washer system that is easier to manufacture than those previously
and currently used.
It is another object of the present invention to provide an improved check valve
for a windshield washer system that requires less manual labor to assemble.
It is yet another object of the present invention to provide an improved check
valve for a windshield washer system that is easier to mold and weld than those
previously and currently used.
Other objects and advantages of the present invention will become readily apparent
as the invention is better understood by reference to the accompanying drawings
and the detailed description that follows.
SUMMARY OF THE INVENTION
The present invention is generally directed to satisfying the need set forth
above and the problems identified with prior check valves for windshield washer systems.
A more generalized form of a preferred embodiment of the present invention takes
the form of a check valve for use in a section of a liquid flow line to control
the intermittent flow of a liquid through the line, wherein the section of the
line that is configured to received the valve has inlet and outlet ends with an
opening through which liquid respectively enters and exits the section. The check
valve includes a compression spring having upstream and downstream ends, wherein
the spring is configured so as to allow the downstream end to press against the
section outlet end. This check valve further includes a piston having bottom, top
and outer side surfaces, with this piston having a cavity that extends from its
top surface and is configured to allow the spring to sit and operated freely within
the cavity with the spring's upstream end resting on the bottom surface of the
cavity. This piston also has an opening in its side surface that connects the cavity
and its outer side surface, and the piston's bottom surface has a raised sealing
surface with an outer boundary that is configured so as to allow the boundary to
enclose the opening in the section's inlet end. This check valve operates by having
its piston's bottom surface press against the section inlet end due to the action
of the spring so as to seal around the opening of the inlet end. The piston is
made from an elastomeric material so as to give the piston the elastic properties
necessary to allow its bottom surface to act as a seal for the inlet opening.
Thus, there has been summarized above, rather broadly, the present invention
in order that the detailed description that follows may be better understood and
appreciated. There are, of course, additional features of the invention that will
be described hereinafter and which will form the subject matter of any eventual
claims to this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a fluidic nozzle incorporating a prior art "ball
and spring" check valve.
FIG. 2 is a sectional view of a fluidic nozzle incorporating a prior art check
valve which has reduced the number of coupling surfaces that have to be sealed.
FIGS. 3(
a)-(
b) are sectional view of a fluidic nozzle
incorporating a prior art check valve which also has a reduced the number of coupling
surfaces to be sealed and shapes for the check valve that are other than the standard,
ball-shaped design.
FIG. 4(
a) is an exploded view of a fluidic nozzle incorporating
a prior art check valve having a "carrier assembly" in place of the prior art "ball
and spring" elements.
FIGS. 4(
b)-(
c) present top and bottom perspective views
of the piston and seal elements that comprise the "carrier assembly" shown in FIG. 4(
a).
FIG. 5(
a) is an exploded view of a fluidic nozzle incorporating
a preferred embodiment of the check valve of the present invention.
FIGS. 5(
b)-(
c) are perspective and assembly views of the
spring and piston components of the check valve of the present invention.
FIGS. 5(
d)-(
e) are top and bottom perspective views of
the piston used in the embodiment shown in FIGS. 5(
a)-(
c)
of the present invention
FIG. 6(
a) is a cross-sectional view of another preferred embodiment
of the present invention.
FIG. 6(
b) is a perspective view of the embodiment shown in FIG. 6(
a).
FIG. 6(
c) is a bottom, perspective view of the piston used in
the embodiment shown in FIGS. 6(
a)-(
b).
FIG. 7(
a) is a cross-sectional view of the bottom surface of the
nozzle housing shown in FIG. 5.
FIG. 7(
b) is a cross-sectional view of the bottom surface of the
nozzle housing shown in FIG. 4, and in which the wall thicknesses of the present
invention can be compared with those attainable using the prior art technology
shown in FIG. 4.
FIG. 8(
a) is a cross-sectional view of top surface of the elbow
shown in FIG. 5.
FIG. 8(
b) is a cross-sectional view of top surface of the elbow
shown in FIG. 4, and in which the contact surfaces of the present invention can
compared with those attainable using the prior art technology shown in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Before explaining at least one embodiment of the present invention in detail,
it is to be understood that the invention is not limited in its application to
the details of construction and to the arrangements of the components set forth
in the following description or illustrated in the drawings. The invention is capable
of other embodiments and of being practiced and carried out in various ways. Also,
it is to be understood that the phraseology and terminology employed herein are
for the purpose of description and should not be regarded as limiting.
A preferred embodiment of the check valve
100 of the present invention
is
shown in FIGS.
5(
a)-(
e). FIG.
5(
a) shows an
exploded view of a windshield washer nozzle assembly and how, as before, the check
valve is fitted into the opening
102 for the fluid flow inlet passage in
the bottom of the nozzle housing
104 or first body member. The check valve
100 itself consists of a spring
106 and an especially configured
and constructed piston
108. An elbow
110 or second body member mates
with the bottom of the nozzle housing to form the assembly's flow channel, i.e.,
fluid flows into the elbow's inlet
112, through the elbow, out of the elbow's
top surface
114, and if the fluid is sufficiently pressurized to overcome
the resisting force of the spring, around the bottom
116 and the outer sides
118 of the piston and into the openings
128 at the top of the piston
and on into the opening
102 for the fluid flow inlet passage in the bottom
of the nozzle housing
104.
In this embodiment, the "carrier assembly" of FIG.
4(
b)-(
c),
consisting of a piston and seal, has been replaced with a single, especially configured
and constructed, elastomeric piston
108. The piston itself has a cavity
120 that extends from its top surface
122 and is configured to allow
the spring
106 to sit on the bottom
124 of the cavity, with the interior
walls
126 of this cavity being sufficiently spaced so that the spring
106
may be compressed down and not have the outer surface of the spring bind on the
cavity's interior walls. Near the top of the sides
118 of the piston, there
exist openings
128 which allow the fluid passing on the outside of the piston
to move towards the centerline of the assembly and continue its flow into the opening
102 for the housing's inlet passage.
The bottom surface
116 of the piston in the embodiment shown in FIG.
5(
e)
has an especially configured raised, sealing surface
130 or O-ring whose
diameter is chosen to be larger than and compatible with the opening
132
in the elbow's top surface
114 so that this sealing surface
130 is
sufficient to seal the opening when the compressed spring
104 is forcing
the sealing surface
130 against the elbow's top surface
114. The
fact that the entire piston is constructed of an elastomeric material makes it
possible to easily shape this surface
130 into the bottom of the piston
and have it be a good sealing surface.
The size and shape of cross-section of the piston
108 shown in FIG. 5
is such as to allow the piston to fit within the nozzle's fluid flow passage. For
the embodiment shown in FIG. 5, the cross-sectional shape of the piston is generally
square, with the length of its diagonal, G, being slightly less than the diameter
P of the fluid passage in which it is to be seated. See FIGS.
5(
a)-(
b).
Shown in FIG.
6(
a) is a side view of another embodiment of the
present invention in which the piston's bottom surface has a sealing surface in
the form of a concentric, sealing rib
134 rather than an O-ring. The tip
136 of this rib is seen to spread outward from its center so as to make
more sealing surface area available for use in sealing flow from the opening in
the elbow's top surface. FIG.
6(
b) shows a perspective view of the
check valve
100 shown in FIG.
6(
a), and FIG.
6(
c)
shows a perspective view in which the bottom surface of the piston shown in FIGS.
6(
a)-(
b) can be seen.
For the embodiments shown in FIGS. 5 and 6, the task of inserting the spring
106 into this piston
108 is relatively simple. One of the advantages
of this arrangement, as compared with the arrangement shown in FIG.
4(
a),
is that the spring is no longer balanced with no means of support on the piston
during assembly of the nozzle. Due to the favorable length to diameter ratio of
this piston
108, the spring
106 is retained within the piston
108
with no cocking during assembly and welding.
Shown in FIG.
7(
a) is a bottom view of the nozzle housing
104
of the present invention which shows the bottom surface
138 surrounding
the opening
102 for the nozzle's fluid flow inlet passage. To make it easier
to join the elbow's top surface
114 to this nozzle surface
138, the
shape of the nozzle surface has been reconfigured from that shown in FIG.
4(
a).
The welding surface
140 now has the simpler shape of a ring compared that
of the discontinuous surfaces used in the prior art; for comparison purposes, see
FIG.
7(
b) which depicts this comparable surface for the prior art
housing shown in FIG.
4(
a). In the present embodiment, the thickness
of this welding surface has also been increased in order to make the task of welding
these pieces easier.
Additionally, as seen by comparing FIGS.
8(
a) and
8(
b),
the top surface
114 of the elbow of the present invention, as shown in FIG.
8(
a), has been made both flatter and larger in contact area than
that of the prior art elbow shown in FIGS.
8(
b) and
4(
a).
This allows for better transfer of welding energy and greatly reduces the difficulty
of welding these parts.
The housing tool of the present invention is much simpler due to its simpler
coring. Higher welding strength can be achieved in the parts of the present invention
and the percentage of parts that have to be scrapped due to fabrication defects
is greatly reduced.
An additional advantage of the present invention is that the elbow of the present
invention may be welded in any orientation, thereby providing greater design and
manufacturing flexibility.
As to a further discussion of the manner of usage and operation of the present
invention, the same should be apparent from the above description. Accordingly,
no further discussion relating to the manner of usage and operation will be provided.
However, it should be noted that the check valve
100 of the present
invention, although it has been discussed only in the context of it being used
in a windshield washer assembly, can be used in many other types of liquid flow
application. For example, in any situation in which it is desired to have a fluid
jet which intermittently exhausts into a gaseous surrounding environment, and in
which it is desired to have this jet to flow on demand so as to quickly assume
a steady state condition, a check valve constructed according to the teachings
herein could be used to help regulate the flow of such a jet.
With respect to the above description then, it is to be realized that the optimum
dimensional relationships for the parts of the invention, to include variations
in size, materials, shape, form, function and manner of operation, assembly and
use, are deemed readily apparent and obvious to one skilled in the art, and all
equivalent relationships to those illustrated in the drawings and described in
the specification are intended to be encompassed by the present invention.
The foregoing is considered as illustrative only of the principles of the invention.
Further, since numerous modifications and changes will readily occur to those skilled
in the art, it is not desired to limit the invention to the exact construction
and operation shown and described, and accordingly, all suitable modifications
and equivalents may be resorted to, falling within the scope of the invention as
hereinafter set forth in the claims.
*
