Note: Descriptions are shown in the official language in which they were submitted.
~737~
This invention relates to valves, and more particularly
to spring-loaded air valves.
The invention is concerned, in one aspect, with a check
valve which in use is connected between an air compressor and a
storage tank for compressed air received from the compressor to
check the return oE air from the tank back to the compressor.
Commonly, the outlet end of the check valve is threaded into the
inlet of the tank, an air line being interconnected between the
air compressor and the valve inlet. A valve of ~his invention is
especially suited to this type of use, that is, where the outlet
end of the valve is threaded into an inlet of a tank. In another
aspect, the invention is concerned with a safety valve for venting
air from means holding air under pressure when the pressure rises
above a predetermined level.
mmary_of the Invention
Among the several objects of this invention may be noted
the provision of an improved spring-loaded valve, eOg., a check
valve or a safetv valve, of simplified and economical construction.
The invention provides a valve comprising a valve body
having a passage extending therethrough to one end of the body
constituting an outlet end of the body, said body having a
cylindric extension at said outlet end, said passage extending
through said extension, the outer end of said extension con-
stituting a valve seat, said extension having a circumferential
groove, a coil spring secured at one encl thereof constituting its
inner end to said extension by engagement thereof in said circum-
ferential groove, said spring extending endwise from said extension
and having at its outer end an inwardly extending en~ portion, a
73'~
valve member confined within the spring be-tween the valve seat and
said inwardly extending end portion of the spring, the spring being
i.n tension and acting via engagement of its said inwardly extend-
ing end portion with said valve member to hold the valve member in
engagement with the valve seat, ~he valve member being movable away
from the seat against the bias of the spring, the spring being of
cylindrical form with its internal diameter corresponding to the
diameter of said extension in said circumferential groove, the
valve member being of circular outline with its external diameter
such that it fits wholly within the internal diameter of the
spring without any part thereof between convolutions of the
spring, whereby the valve member is held confined in the spring
solely by said inwardly extending end portion of -the spring.
Other features will be in part apparent and in part
pointed out hereinafter.
Brief Description of the Drawings
Figure 1 is a longitudinal section of a check valve of
the present invention installed in a tapped hole such as the inlet
of a compressed air tank, shown with the valve closed;
Figure 2 is a section similar to Figure 1 showing the
Figure 1 valve open;
Figure 3 is an end view of the outlet end of the E'igure
1 valve;
Figure 4 is a longitudinal section of a safety valve of
the present invention, showing the valve closed; and
Figure 5 is a transverse section on line 5 5 of Figure
4.
~8~
Corresponding reference characters indicate corresponding
parts throughout the several views of the drawings.
2a
Description of the Preferred Embodiment
Referring first to Figs. 1-3 of the drawings, a
check valve of this invention, designated in its entirety
by the numeral 1, is shown installed in a tapped hole
such as the threaded inlet 3 in the wall 5 of a storage
tank; such as a storage tank for compressed air supplied
from an air compressor via the check valve 1. The in- -
terior surface of the storage tank wall is designated 7
and the exterior surface is designated 9.
~s shownl the check valve 1 comprises an e-
longate valve body 11 of metal, such as brass, having an
axial passage 13 extending therethrough from its inlet
end 15 to its outlet end 17~ The inlet end of the body
has external threads 19 for connection of a line from an
air compressor, for example, and has a hexagonal head 21
downstream of threads 19 which will accept a wrench.
Downstream of ~he hexagonal head, the body has an
externally-threaded cylindric portion or shank 23 for
threading into inlet 3 of the storage tank. At its
outlet end, downstream of threaded cylindric portion 23,
the valve body has a reduced-diameter cylindric extension
25 of lesser diameter than inlet 3. The extension has a
relatively coarse external screw thread 27 providlng a
circumferential groove.
A coil spring 29 of cylindrical form is secured
to the outside of the reduced-diameter extension 25 of
the valve body and extends endwise from the body (down~
stream therefrom) coaxial with the body. The diameter of
the spring is less than that of the storage tank inlet 3
and large enough snugly to fit over extension 25 and
~1~7~7~
interengage with its screw thread 27. The diameter of
the spring wire forming the spring is relatively small,
whereby the coils of the spring are relatively deepIy
engaged in the thread 27 firmly to secure the spring to
the valve body. As shown in Fig. 3, the spring has an
inwardly spiraling convolution 31 at its downstream end
generally in a transverse plane of the spring forming a
radially inwardly extending portion of the spring which
partially closes its outer (downstream) end.
A valve member 33, preferably though not neces-
sarily of a suitable plastic, such as glass-fiber-filled
polytetraEluoroethylene, for example, is disposed concen-
trically within the spring between the end 17 of ~he ex-
tension 25 of the valve body, which constitutes the valve
seat of the check valve, and the inwardly spiraling
convolution 31 of the spring, being confined within the
spring by the convolution. The valve member is shown in
the drawings as a relatively thick disc, but members of
other shapes may be used, for example a ball. The spring
is of such length that, as assembled with the valve body
with the valve member within the spring between the seat
17 and the spring end convolution 31, the spring is
placed in tension by the presence of the valve member.
Convolution 31 engages the outside (the downstream side)
of the valve ~ember and, as shown in Fig. 1, normally
seats the valve member against the outlet end or valve
seat 17 of the valve body, closing ~he outlet end of
passage 13. ~s shown in Fig. 2, the valve member 33
opens against the bias of the spring when the pressure
upstream of the valve member (within passge 13) exceeds
the pressure downstream of the valve member by an amount
which exceeds the spring tension.
73'7~
The check valve of this invention as described
above is inexpensive and easy to assemble, having a mini-
mum number of parts (three parts - the body, spring and
valve member). Because the moving parts of the valve
(spring 29 and valve member 33) are not enclosed by the
valve body, they are readily inspected without disas~
sembly o the valve. The valve is especially suited to
uses in which the outlet end of the valve is threaded
into an inlet in a storage tank or other enclosed space,
the moving parts being protected (by being enclosed in
the tankj against dirt and damage. It also appears that
the valve is characterized by lower pressure losses
thereacross in comparison with prior valves having a
spring retainer.
Referring to Figs. 4 and 5 of the drawings, a
safety valve of this invention, designated in its en-
tirety by the numeral 35, comprises an elongate tubular
other shapes may be used~ for example a ball. The spring
is of such length that, as assembled with the valve body
with the valve member within the spring between the sea~
17 and the spring end convolution 31, the sprirlg is
placed in tension by the presence of the valve member.
Convolution 31 engages the outside (the downstream side)
of the valve member and, as shown in Fig. 1~ normally
seats the valve member against the outlet end or valve
seat 17 of the valve body, closing the outlet end of
passage 13. As shown in Fig. 2, the valve member 33
opens against the bias of the spring when the pressure
upstream of the valve member Iwithin passge 13) exceeds
the pressure downstream of the valve member by an amount
which exceeds the spriny tension.
3'7~
The checls valve of this invention as described
above is inexpensive and easy to assemble, having a mini-
mum nurnber of parts (three parts - the body, spring and
valve member). Because the moving parts of the valve
(spring 29 and ~alve member 33) are not enclosed by the
valve body, they are readily inspected without disas-
sembly of the valve. ~he valve is especially suited to
uses in which the outlet end of the valve is threaded
into an inlet in a storage tank or other enclosed space,
the moving parts being protected (by being enclosed in
the tank) against dirt and damage. It also appears that
the valve is characterized by lower pressure losses
thereacross in comparison with prior valves having a
spring retainer.
Referring to Figs. 4 and 5 of the drawings, a
safety valve of this invention, designated in its en-
tirety by the numeral 35, comprises an elongate tubular
valve body 37 of metal, such as brass, having an axial
passage 39 therethrough from its inlet end 41 to its
outlet end 43. The body has a hexagonal head 45 inter-
mediate its ends for application of a wrench to turn the
valve. Upstream of the head, the body has a first
externally-threaded portion or shank 47. Downstream of
the head, the body has a second cylindric portion 49
having an annular external flange 51 spaced closely
adjacent the head and external threads 53 downstream of
the flange. At its outer end, cylindric portion 49 is
formed with a circular internal recess 55 having a valve
seat 57 projecting downstream within the recess. The
downstream end of seat 57 is upstream oE khe downstream
end of cylindric portion 49.
3'7~
A coil spring 59 of cylindrical form is
threaded on the screw thread 53 on the outside of cy-
lindric portion 49 and extends endwise (downstream)
therefrom coaxial with the body. The diameter of the
spring wire forming the spring is relatively small,
whereby the coils of the spriny are relatively deeply
engaged in the thread 53. As shown in Fig. 5, the spring
has an inwardly spiraling convolution 61 forming a radi
ally inwardly extending portion of the spring at its
downstream end generally in a plane transverse of the
spring, constituting means for engaging and conEining a
valve member, generally designated 63, within the spring.
Valve member 63 is comprised of a valve disc 65
having a central reduced-diameter cylindric portion 67 on
its upstream side engageable in recess 55 on the outlet
end of the valve body. Cylindric portion 67 has a
central circular recess 69 in which is secured a disc-
shaped resilient seal 71 (of a suitable elastomeric
material) engageable with valve seat 57. The valve
member has a stem 73 projecting downstream from valve
disc 65 through the spring's end convolution 61. Stem 73
has a transverse hole 75 at its downstream end through
~hich a ring pull 77 is looped.
A cover 79 is provided for the downstream end
of valve 35 in the form of a cylindrical cap surrounding
and spaced from cylindrical portion 49 of valve body 37,
spring 59 and valve disc 65. The cover is secured at its
upstream end to the valve body by crimping its rim 81
under flange 51 between the flange and hexagonal head
45. The cover has a number of fluid (air) exit openings
or ports 33 (e.g., four such ports) through its side wall
and has a central opening 85 in its downstream end
through which stem 73 projects.
'737~
In use, the safety valve 35 is threaded into a
tapped hole in communication with a pressurized space and
operates to l.imit the pressure of fluid within the
space. As shown in Fig. 4, spring 59 normally biases
valve disc 65 against valve sea-t 57. Valve member 63
opens against the bias of spring 59 when the pressure
upstream of the valve disc exceeds atmospheric pressure
(the pressure downstream of the val~-e disc) by an amount
which exceeds the spring force. Pressurized fluid then
esca~es past ~he valve disc and through ports 83. In the
manufacture of the valve, the spring 59 is initially
threaded on the screw thread 53, before application of
the cover or cap 79, to the point where the bias of the
spring on the valve member 63 corresponds to the desired
blow-off pressure. The spring holds itself in its
adjusted position, thereby to maintain the pre-set blow-
off pressure. The cover or cap is then applied, and
functions to prevent tampering with the spring. The
valve may be manually opened at any time by pulling on
the ring 77.
In view of the above, it will be seen that the
several objects of the invention are achieved and other
advantageous results attained.
As various changes could be made in the above
constructions without departing from the scope of the
invention, it is intended that all matter contained in
the above description or shown in the accompanying draw-
ings shall be interpreted as illustrative and not in a
limiting sense~
