Retained seat check valve

A unique, inexpensive and easily manufactured check valve device features a valve housing, a valve seat, a resilient ring seal, a retaining sleeve, a valve member and a valve spring. The valve housing defines an inlet channel, an outlet channel and at least one valve bore through which the inlet and outlet channels interconnect. Formed in the valve bore is the valve seat. The valve seat has a generally flat annular surface from within which an opening emerges into a preferred one of the two channels. The resilient ring seal is situated atop, and is coaxial with the opening defined by, the flat annular surface of the valve seat. Situated within the valve bore, the retaining sleeve serves to retain the resilient ring seal by its periphery against the flat annular surface of the valve seat. The valve member is moveable within the retaining sleeve. By its head portion at one end, the valve member is adapted to be pressed against, and form a leak-proof seal with, the resilient ring seal. Compressively disposed within the valve bore against a non-seat facing side of the valve member, the valve spring compels the head portion of the valve member against the resilient ring seal. The check valve device is thus normally biased in a closed position wherein the preferred channel is cut-off from the valve bore of the valve housing.

FIELD OF THE INVENTION 
The invention generally relates to check or poppet type valves that are 
commonly employed in many of the pneumatically or electropneumatically 
based systems currently in use in the railroad industry. More 
particularly, the invention pertains to a type of check or poppet valve 
whose design employs a resilient or soft ring seal as part of the valve 
seat against which a relatively hard valve member seats when the valve 
device is biased to or otherwise placed in the closed position. 
BACKGROUND OF THE INVENTION 
Examples of the types of systems in the railroad industry to which the 
invention may be applied include air drying systems or air brake control 
systems such as those produced and sold by the Westinghouse Air Brake 
Company (WABCO). 
Representative of the type of environment to which the invention may be 
applied is the twin tower air drying system disclosed in U.S. Pat. No. 
5,715,621. This twin tower air drying system is capable of providing a 
continuous stream of cleaned and dried compressed air to any of the 
various types of air brake control systems manufactured by WABCO. As shown 
in FIG. 3 of that patent, the twin tower system features two air drying 
assemblies (each containing a desiccant cartridge), two inlet check 
valves, two outlet check valves, two purge check valves and a control 
mechanism that coordinates operation of the check valves according to a 
preset operating cycle. 
Whether used in air drying systems, brake control systems or other types of 
pneumatic apparatus, check and poppet type valve devices of varying design 
are used to establish, cutoff, or otherwise manipulate the flow of air in 
the systems in which they are employed. As shown in FIG. 1, one type of 
prior art check valve device is comprised of a valve element 1, a valve 
spring 2 and a valve seat 3, all of which accommodated within a chamber 4 
defined in the housing of the valve device. The housing of the valve 
device also typically defines an inlet channel and an outlet channel by 
which the valve device pneumatically connects to or within the pneumatic 
system with which it is used. The valve chamber 4 is composed of one or 
more contiguous bores drilled into or otherwise formed in the valve 
housing. It is through this valve chamber 4 that the inlet and outlet 
channels interconnect. 
Referring still to the basic features of the check type valve device of 
FIG. 1, the valve seat 3 features a surface 30 within which is defined an 
opening from which one of the channels emerges. The surface 30 of valve 
seat 3 may take, in part, the form of a raised seat ring 31. Typically 
made of rubber or other known elastomeric compound, the valve element 1 
takes the form of a disk-shaped body whose width depends on the particular 
type of valve device at issue. Molded into the valve element is a metal 
(e.g., brass) insert 40 to endow the otherwise soft disk 1 with high 
degree of stiffness and strength. Projecting from the periphery of the 
elastomeric disk 1 is thus a plurality of metal prongs 5 so as to give the 
valve element 1 a fluted periphery, as best shown in FIG. 1A. The prongs 
thus aid the flow of air through the valve device. By these prongs, the 
valve element 1 is also guided in its movement within the main bore of the 
valve chamber 4. Formed at, or otherwise attached to, the seat facing side 
of the disk 1 is the valve head 10. The non-seat facing side of the disk 
typically takes the form of a short shaft or protuberance 11, as shown in 
FIG. 1. Typically held in compression between the non-seat facing side of 
the valve head 10 and a spring stop formed at one end of its bore in the 
valve housing, the spring 2 surrounds the protuberance 11. The spring 2 
may also be held in compression between a snap ring secured to the 
cylindrical wall of its bore and the non-seat facing side of the valve 
head 10. The main bore of valve chamber 4 and the valve spring 2 together 
act as a guide to assure proper alignment of the valve head 10 with the 
valve seat 3. It is the valve spring 2 that provides the bias necessary to 
keep the valve head 10 in its normally closed position against the raised 
seat ring 31 of valve seat 3. 
Shown in FIG. 2 is another type of prior art check valve device. This valve 
device is similar to that shown in FIG. 1 except for the structure of the 
valve element 1 and the valve seat 3. Specifically, the valve seat 3 
features a flat rigid annular surface 32 rather than the raised ring seat 
31 illustrated in FIG. 1. Correspondingly, the valve element 1 features a 
raised sealing ring 12 formed on the seat facing side of its valve head 10 
rather than the flat sealing surface depicted in FIG. 1. Like the valve 
device shown in FIG. 1, the valve element 1 contains the metal insert 40. 
The valve element 1 is thus fluted in its periphery as it has the 
plurality of metal prongs 5 along its periphery, as shown in FIG. 2A. The 
main bore of chamber 4 and the valve spring 2 together act as a guide to 
assure proper alignment of the valve head 10 with the valve seat 3. The 
valve spring 2, of course, provides the bias necessary to keep the raised 
sealing ring 12 of valve head 10 in its normally closed position against 
the flat annular surface 32 of valve seat 3, as shown in FIG. 2. 
Another type of prior art check valve device is illustrated in FIG. 3. This 
valve device features a valve element comprised of a circular elastomeric 
disk 50 and a molded plastic housing 60 in which the elastomeric disk 50 
is housed. Akin to the metal insert 40 of the previously described valve 
devices, the plastic housing 60 provides stiffness to, strengthens and 
otherwise supports the soft elastomeric disk 50 so that it can resist 
deformation and otherwise withstand the stresses of the environment in 
which the valve element is used. Projecting from the periphery of the 
plastic housing 60 is a plurality of prongs 5. The prongs give the valve 
element a fluted periphery, as shown in FIG. 3A, and aid the flow of air 
through the valve device when the valve element, by the seat facing side 
of the elastomeric disk 50, is unseated from valve seat 3. It is also by 
these prongs that the valve element is guided in its movement within the 
main bore of valve chamber 4. Projecting from the surface 30 of valve seat 
3 is a raised seat ring 31, as shown in FIG. 3. The valve spring 2 
provides the bias necessary to keep the valve element in its normally 
closed position wherein the elastomeric disk 50 is sealingly positioned 
against the raised seat ring 31 of valve seat 3. 
Referring now to the poppet type valve device shown in FIG. 4, this valve 
device features a valve element 1, a valve spring 2 and a valve seat 3 all 
within the chamber 4 defined in the housing of the valve device. The valve 
element 1 is comprised of a metal valve member 17 and an annular 
elastomeric seal 18. Projecting from the periphery of the metal valve 
member 17 is a plurality of prongs (not shown). As known to those skilled 
in the art of making valves, this gives the valve element a fluted 
periphery and aids in the flow of air through the valve device. The metal 
valve member 17 is typically made of brass, and defines an annular recess 
in its flat bottom surface 19. Molded into this annular recess is the 
annular elastomeric seal 18. The valve seat 3 features a raised seat ring 
31. The valve spring 2 provides the bias necessary to keep the valve 
element 1 in its normally closed position wherein the annular elastomeric 
seal 18 is sealingly engaged against the raised seat ring 31 of valve seat 
3. The poppet valve device further includes a piston actuated stem 70. One 
end of stem 70 is disposed in the lower channel with its head end opposite 
the center part of bottom surface 19 of metal valve member 17. An o-ring 
71 is disposed in an annular recess defined in the cylindrical wall of 
stem 70. This o-ring prevents leakage of air from the valve device when 
the stem 70 is piston actuated further into the lower channel to unseat 
the valve element 1 from the raised seat ring 31 of valve seat 3. 
Check and poppet type valve devices range from simple to complex in design. 
Quite often they must be manufactured to rather exacting dimensions so as 
to assure proper control and/or containment of air in systems that require 
relatively high operating pressure(s). Consequently, abutting valve 
surfaces must often be carefully machined so that the valve device when 
closed can provide an air tight seal between the corresponding surfaces of 
the valve element and the valve seat. 
To resist deformation and otherwise withstand the stresses of the 
environment in which they are used, valve elements have traditionally been 
made so that they possess a high degree of stiffness and strength. 
Manufacturers such as WABCO, for example, have molded into their 
elastomeric valve elements 1, such as the ones shown in FIGS. 1 and 2, a 
brass insert 40 to endow the otherwise soft valve elements 1 with these 
characteristics. U.S. Pat. Nos. 5,213,749 and 5,303,937, assigned to WABCO 
and incorporated herein by reference, teach yet another type of prior art 
elastomeric valve element 41 into which a metal insert 61 has been molded. 
There are several shortcomings inherent to check and poppet valve devices 
of the type that employ the soft valve elements 1 shown in FIGS. 1 and 2. 
The various prior art processes by which such stiffened valve elements are 
made are quite complex. During manufacturing, for example, the brass 
insert must be carefully loaded into, and positioned within, the mold so 
that the rubber or like compound can properly flow and form around the 
metal insert. Subsequent to the molding process, the flashing that is 
commonly produced during the molding operation must also be removed. These 
tasks add cost to both the manufacturing and quality control processes. 
Consequently, various alternatives to the use of brass inserts have been 
investigated, such as using a molded plastic housing 60 as a carrier for 
the type of sealing element 50 shown in FIG. 3. This type of housing 
provides the necessary rigidity and strength to the elastomeric sealing 
element. Unfortunately, the molded plastic housing option and various 
other alternatives, such as the one shown in FIG. 4, have also proven to 
be unduly complex and/or costly to implement. 
The foregoing background information is provided to assist the reader to 
understand the invention described and claimed below. Accordingly, any 
terms used herein are not intended to be limited to any particular narrow 
interpretation unless specifically stated otherwise in this document. 
OBJECTIVES OF THE INVENTION 
It is, therefore, a primary objective of the invention to provide an 
improved check/poppet type valve device that is considerably easier to 
manufacture and less expensive than check/poppet valve devices currently 
known. 
Another objective is to provide a check or poppet valve device whose 
resilient sealing element does not require a metal insert to be molded 
into it or bonded to it. 
Yet another objective is to provide a check/poppet valve device whose 
construction employs use of a tubular sleeve to retain a resilient ring 
seal atop an annular valve seat by which the necessary airtight seal 
between the valve head and the valve seat is provided when the valve 
device is closed. 
In addition to the objectives and advantages listed above, various other 
objectives and advantages of the invention will become more readily 
apparent to persons skilled in the relevant art from a reading of the 
detailed description section of this document. The other objectives and 
advantages will become particularly apparent when the detailed description 
is considered along with the following drawings and claims. 
SUMMARY OF THE INVENTION 
In a first presently preferred embodiment, the invention provides a check 
valve device for use with a pneumatic system. The check valve device 
comprises a valve housing, a valve seat, a resilient ring seal, a 
retaining sleeve, a valve member and a valve spring. The valve housing 
defines an inlet channel, an outlet channel and at least one valve bore 
through which the inlet and outlet channels interconnect. Formed in the 
valve bore is the valve seat. The valve seat has a generally flat annular 
surface from within which an opening emerges into a preferred one of the 
two channels. The resilient ring seal is situated atop, and is coaxial 
with the opening defined by, the flat annular surface of the valve seat. 
The resilient ring seal has an outer periphery that abuts against an 
interior cylindrical wall of the valve bore. Situated within the valve 
bore, the retaining sleeve has an outer cylindrical wall that abuts 
against the interior cylindrical wall of the valve bore. It also has a 
bottom that sits atop a peripheral portion of the resilient ring seal 
thereby sealingly retaining the resilient ring seal against the flat 
annular surface of the valve seat. Preferably fluted, the valve member is 
moveable within this retaining sleeve. By its head portion at one end, the 
valve member is adapted to be pressed atop and against, and form a 
leak-proof seal with, an inner portion of the resilient ring seal. 
Compressively disposed within the valve bore against a non-seat facing 
side of the valve member, the valve spring compels the head portion of the 
valve member against the resilient ring seal. The check valve device is 
thus normally biased in a closed position wherein the preferred channel is 
cut-off from the valve bore of the valve housing.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 5 illustrates the essential details of a presently preferred 
embodiment of a check/poppet type valve device 100. The check/poppet valve 
device 100 includes a valve member 110, a valve spring 120, a valve seat 
130, a resilient ring seal 140 and a retaining sleeve 150, all of which 
housed within a chamber 101 defined in the housing 105 of the valve device 
100. The housing 105 of the valve device 100 also defines an inlet channel 
and an outlet channel by which the valve device 100 pneumatically connects 
to or within the pneumatic system with which it is used. The valve chamber 
101 is composed of one or more contiguous bores drilled into or otherwise 
formed in the valve housing 105, as is clear from FIG. 5. It is through 
this valve chamber 101 that the inlet and outlet channels interconnect. 
The valve member 110 may take the form of a disk-shaped body, and may be 
composed of metal, such as aluminum, or of a plastic compound via a 
molding process. It may also be made of any number of other suitable 
materials all of which well known in the pneumatic and hydraulic arts. The 
width of the disk-shaped valve member 110 can be tailored to the demands 
of the environment in which the invention will be used. Formed at, or 
otherwise attached to, the seat facing side of the valve member is the 
head portion 111. The non-seat facing side of valve member 110 typically 
takes the form of a short shaft or protuberance 112. The valve seat 130 
features a flat rigid annular surface 131 within which is defined an 
opening from which a preferred one of the inlet and outlet channels 
emerges. 
Composed of rubber or other suitable elastomeric material of a type well 
known in the pneumatic and hydraulic arts, the resilient ring seal 140 is 
situated atop, and is generally coaxial with the opening defined by, the 
flat annular surface 131 of valve seat 130. Optionally, adjacent this flat 
annular surface within the cylindrical inside wall of the main bore, there 
can be formed an annular recess (not shown) adapted to contain an 
outermost ring (not shown) of resilient seal 140. By its head portion 111 
at one end, the valve member 110 is adapted to be pressed against, and 
form a leak-proof seal with, an inner portion 141 of resilient ring seal 
140. 
Preferably situated within the main valve bore is the retaining sleeve 150. 
Ideally, the retaining sleeve 150 is tubular or cylindrical in shape and 
is disposed concentrically within the cylindrical inside wall of the main 
bore of valve housing 105. Moveable within the retaining sleeve 150 is, of 
course, the valve member 110. Situated near an end of a preferred one of 
the valve bores, a retaining means 160 is used to clamp the retaining 
sleeve 150 in the main bore between it and a peripheral portion 142 of 
resilient ring seal 140. The retaining means 160 may also be used to hold 
the valve spring 120 in compression between it and the non-seat facing 
side of the valve member 110. 
The retaining means 160 may be implemented in any number of ways well known 
to those skilled in the art of making pneumatic and hydraulic valves. For 
example, the retaining means 160 may take the form of a snap ring 161 
attachable to a cylindrical inside wall of the one of the valve bores. The 
snap ring 161 may be secured within the cylindrical wall using known prior 
art practice such as by snapping it into a groove defined in the wall. 
Alternatively, the retaining means 160 may take the form of a cover 162 
for the valve device 100. The cover 162 may be secured onto the top of 
valve device 100 using known prior art practice such as by adhesive, 
welding, or snaps. 
Disposed in the aforementioned manner within valve chamber 101, the 
retaining sleeve 150 provides the requisite clamping load to hold the 
resilient ring seal 140 firmly in place. The retaining sleeve 150 thus 
enables ring seal 140 to provide an airtight seal along its periphery 
against the flat annular surface 131 of valve seat 130. The retaining 
sleeve 150 further enables the resilient ring seal 140 to resist 
deformation and otherwise withstand the stresses of the environment in 
which it will be used. Employed in this manner with retaining sleeve 150 
and retaining means 160, the resilient ring seal 140 possesses a high 
degree of stiffness and strength. 
As illustrated in FIG. 5, the valve spring 120 at its lower end preferably 
surrounds the protuberance 112 on the non-seat facing side of valve member 
110. The retaining sleeve 150 and the valve spring 120 thus together act 
as a guide to assure alignment of the head portion 111 of valve member 110 
with the valve seat 130. Compressively disposed within its bore between 
the retaining means 160 and the non-seat facing side of valve member 110, 
it is the valve spring 120 that compels the head portion 111 of valve 
member 110 against the resilient ring seal 140. In this manner, the 
check/poppet valve device 100 is biased in a closed position wherein the 
preferred channel is cut-off from the main bore of valve housing 105. 
Referring now to FIG. 5A, the periphery of valve member 110 is fluted so as 
to further aid the flow of air through valve chamber 101 when the valve 
device 100 is placed in the open position. From the perspective of FIG. 5, 
in the open position, the valve member 110 is moved upwardly thereby 
forcibly unseating the head portion 111 from the resilient ring seal 140 
against the compressive force of spring 120. Alternatively, the retaining 
sleeve 150 may be fluted to accomplish the same purpose. This is shown in 
FIG. 5B. 
The presently preferred embodiment of the check/poppet valve invention has 
been set forth in detail according to the Patent Act. Those persons of 
ordinary skill in the art to which this invention pertains may 
nevertheless recognize various alternative ways of practicing the 
invention without departing from the spirit and scope of the following 
claims. Those of such skill will also recognize that the foregoing 
description is merely illustrative and not intended to limit any of the 
ensuing claims to any particular narrow interpretation. 
Accordingly, to promote the progress of science and the useful arts, I 
secure for myself by Letters Patent exclusive rights to all subject matter 
embraced by the following claims for the time prescribed by the Patent 
Act.