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Patented Dec. 3, 1946
Max A. Mathys, Detroit, Mich., asslgnor to Ex
Ce‘ll-O Corporation, Detroit, Mich., a corpora
tion of Michigan
Application July 14, 1943. Serial No. 494,609
5 claims. (ci. 1st-_ssi
The present invention relates to improvements
in relief valves for fluid pressure systems, and has
particular reference to a new and improved valve
adapted to divert fluid from a pressure line when
the pressure therein tends to rise above a pre
determined maximum.
One of the objects of the present invention is
to provide a novel relief valve in which the clos
ing pressure is more closely related to the open-ing pressure than in the case of conventional re
lief valves of the poppet type or piston type.
Another object is to provide a new and im~`
proved relief v alve
in which the closing pressure
- effective to teminste the n_uid flow is substan
one embodiment of the invention adapted pri
marily for use as a working pressure relief valve
in a hydraulic transmission system. _ For purposes
of illustration, the valve Il! is shown connected
in a simple system having a pump II taking hy
draulic fluid through an intake line I2 from a
supply reservoir I3. The pump I-I has a discharge
line Il for conducting fluid under pressure to a
point of u_se, such as a hydraulic actuator (not
The valve I0 is connected in the system through
an inlet pressure line I! branching from the pump
discharge line I4, and an outlet relief line I6 lead
- ing back to the reservoir I3, and in normal use
is operable to bypass any excess iiuid so as to .
tially the same as the opening pressure effective 16 limit the discharge pressure of the pump to _a
to Iinitiate the fluid flow, said pressures difier ` ' predetermined adjustable maximum working pres
ing, if at all, only to the slightest possible extent.
Still 'another object is to provide a novel relief
In its exemplary form, the valve II) comprises a
valve in which av dynamic force generated as an
main body I1 preferably cylindrical in shape.
incident to a change in direction of ñuid flow
One end of the body I1 is -formed with a rela
through the valve is utilized to supplement the
tivelylarge bore I8 constituting a spring cham
closing pressure of a spring in opposition to the
ber and connected through an outlet passage I9
normal opening pressure of the fluid at the inlet
-to the relief line Il. A screw plug 20 is adjust-l
acting on the valve member.
ably threaded Into the outer endA of the bore I8
Other objects and advantages will become ap ' 25 to close the latter, and is normally secured in
parent asthe description proceeds.
' position of adjustment by means of a lock nut
Inthe accompanying drawings,
' 2I threaded thereon against the end of the body
Figure 1 is a fragmentary view of the hydraulic
I1. Also threaded onto the outer yend of the screw
>transmission system including a relief valve in'
plug 2li to enclose the latter is a cap nut 22.
longitudinal section and on an enlarged scale em-A
The opposite end of the valve body I1 is formed
bodying the features of my invention. '
with a vrelatively-small valve bore 23 opening co
Figs. 2 and 3 are transverse sectional views of
axially to the bore I8. The outer end of the valve
the valve taken along lines 2,-2 and 3--3 of Fig. 1. - > _bore 23 is formed with a >counterbore 24 closed
Fig. 4' is a. longitudinal sectional view of a re
lief valve constituting a’modiiled form of the
' Invention.
~Ii’ig. 5 is a transverse sectional view taken along
line 5-5 of Fig. 4.
by a screw plug 25 and constituting a pressure
chamber. Formed in the inner peripheral sur- ‘
face of the valve bore 23 intermediate its ends is
an annular groove 2l connected through an in
let passage 21 to the pressure line I5. A restricted
Fig. 6 is a fragmentary view partially in lon
snubber channel or passage 28 opens from the
gitudinal section of a relief valve constituting 40 passage 21 to the chamber 2| to conduct fluid
another modi-fled form of the invention.
thereto at the valve inlet pressure.
Fig. 7 is a transverse sectional view taken along
A sleeve valve member 29 extends through the
line 1--1 of Fig. 6.
valve bore 23 with a snug sliding fit. The outer ì
While the invention is susceptible of various
end of the valve member 29 is closed, and pre~modifications and alternative constructions, 1_
sents a valve opening pressure area exposed to the
have shown in the drawings and'will herein de
'pressure in the chamber 24. The inner end por
scribe in detail the preferred embodiment; but it
tion of the member 29~-is formed with an axial
' is to- be understood that I do not thereby intend
-bore 30 opening to the chamber I8. The mem
to limit the inventionto the specific form dis
ber 29 is >also formed in the outer periphery with
closed, but intend to cover al1 modifications and
an annular groove I_I connected through a plu
alternative constructions falling within the spirit ` rality of spaced radial ports 32 with the inner
and scope of the invention as expressed in the
end of the bore 30, and adapted for movement
appended claims.
into and out of communication with the'groove
Referring more particularly to the drawings,
2t. vThus, the grooves 26 and 3| constitute the
the valve IU shown in Figs. l to 3 constitutes
valve ports, and are movable out of communica
end portion of the bore 31 opens directly to the
inlet passage 21H, and is adapted to be closed by a
screw plug 4I. The outer end portion of the bore
31, which preferably is enlarged in diameter to
facilitate insertion and removal of the plug 4I,
is likewise adapted to be closed by a screw plug
42, and is connected to the pressure chamber 24a
directly through a. restricted port 43, and also
tion to close the valve I0, and into varying degrees
of registration to open the valve. The path of
flow through the valve I0 is from the inlet pas
sage 21 through the ports 2B and 3I, and radially
through the ports 32 into the bore 30, and thence
at right angles through the bore 3|J and chamber
I8 to the outlet passage I9.
The position of the valve member 29 is con
through a passage including a check valve 44.
trolled by a coiled compression spring 33 acting 10 In the present instance, the check valve 44 has an
thereon in a direction to close the valve I 0 in
opposition to a valve openingr pressure exerted by ,
inlet passage 45 opening from the bore 31 to a
the fluid at the inlet»I 21. The fluid ypressure is
transmitted from the inlet passage 21 through
the snubber passage 28 to the chamber 24 wherein
normally urged by a light compression spring 49
it acts against the end face area of the valve
member 29. Thus, the valve opening area is of
ñxed size so that the opening pressure varies only
as the pressure of the inlet fluid, and is not di
of the passage 45.
When the valve Ill*l is to be adapted for pump
pressure control to operate in substantially the
transverse bore 46 in turn open to the chamber
24* through a` connecting bore 41, and a ball 48 .
within the bore 43 against a seat 50 at the end
same manner as the valve I0 of Figs. 1 to 3, the
rectly disposed in the path of fluid iiow through 20 plug 4I is removed and the plug 42 is inserted.
the valve I0.
The inlet passage 21‘l is then connected through
The spring 33 is disposed within the chamber
the bore 31 and the port 43 to the pressure cham-~
I8, and seats at the outer end statically against
ber 24a. When the valve I0“ is to be adapted,the screw plug 20 about a centering pilot 34. The
for orifice pressure control, the plug 4I is inserted
inner end of the spring 33 engages a spring pilot 25 andthe plug 42 is removed, and the bore 31 is
washer 35 fixed on the valve member 29. The
connected to the orifice control line 3'8. In this
valve closing pressure exerted by the spring 33
condition, the passage 21ß is blocked from the
may be varied by adjusting the screw plug 20
chamber 24“ so that the valve I0' is not respon
which is provided with a hexagon head 36 to
facilitate such adjustment.
sive to the inlet pressure from the pump dis
30 charge line I 5*. In both adaptations, pressure
In operation, when the fluid pressure in the
inlet line I5 from the discharge line I4 of the
pump I I is below the normal working pressure,
at which the valve In is set to open, the pressure
of the fluid within the chamber 24 acting on the 36
valve member 29 is> insufhclent to overcome the
force of the spring 33, so that the ports 29 and
3I are completely out of registration to interrupt
the bypass or relief of iiuid. As the pressure in
rises are freely transmitted through the check
valve 44 to the pressure chamber 24‘, but in the
event of a drop in the control pressure the result
ing closing movement of the valve member 29“
is snubbed or dampened due to the restriction to
âlêiid egress from the chamberv through the port
In oriilce pressure control, the operation of the
valve is responsive to the pressure established in
the chamber 24 rises, it acts against the valve 40 -the line 33,by the flow restriction through the
member 29 to move the port 3| progressively
oriilce 39. Such oriñce may be arranged in vari
toward and then into varying degrees of regis
ous types of control systems, for example to re
tration with the port 25 to open the valve. With
ceive and meter ñuid discharging from an actu
the valve in open position, av portion of the iluid
ator which in turn is motivated by fluid under
from the inlet line I5 is bypassed. The change 45 pressure from the pump II, as in the patent to
Alden No. 2,000,553.
in direction of flow of the fluid issuing from theradial ports 32 within the bore 30 of the valve
Figs. 6 and 7 disclose another modiñed form
member 29 generates a dynamic force which acts
of the invention which is generally similar to that
on the valve member 29 in a direction to supple-- ^
shown in Figs. 4 and 5 and, therefore, correspond
ment the force oi' the spring 33. Variation in the, 50 ing parts are identified by like reference numerals,
volume of flow through the valve will result in a
with the addition of the subscript "b”. In this
corresponding variation in the dynamic force.
case,` a valve sleeve 5I is ñxed in the valve bore
Because of the control factors ofthe valve I0,
23h to receive the valve member 29h, and is Aformed
the opening pressure and the closing pressure are
with an annular groove 52- in communication
approximately the same, and the desired maxi 55 with the inlet passage 21'?. 'I‘he sleeve 5I is formed
»mum working pressure is effectively maintained'
with a plurality of peripheral ports 53 opening
within an extremely small range of variation.
Figs. 4 and 5 illustrate a modiñed form of relief
valve which is convertible for use either as a
pump pressure control, as inthe case oi the form
of Figs. 1 to 3, or as an oriñce pressure control.
The construction is generally similar to that dis
closed in Figs.v 1 to 3, and corresponding parts
are, therefore, identified by the same reference
numerals, with the added subscript “a”,
In the modified form of Figs. 4 and 5, the outer
end oi' the valve bore 23* does not open to the
extreme end of the body I1, but terminates
short thereof, and is diametrically enlarged to
from the groove 52 to the inner bore for corn
munication with the groove 3 Ib in the valve mem-y
ber 29h.
'I'he valve member 29b isyso constructed that
the downward dynamic ñow reaction tending to
urge the valve toward closed position will in
crease more rapidly than in the preceding forms
upon an increase in the rate of flow so as to
eii’ect rapid closing. The ports 32b in the valve
>member 29b and the ports 53 in the sleeve 5I are
radially inclined inwardly toward the closed end
of the valve member, and the latter is formed in
' termediate' the ports 32b with a curved central
_ define the pressure chamber 24B. Formed in the 70 projection or baille 54 extending longitudinally
body I1 is a longitudinal ’bore 31 for connecting
the pressure chamber 24'» optionally either to
the inlet passage 215. or'to an outside line 38
leading from the upstream side of an adjustable
of the bore 30". Whereas, in the first two forms,
duid passing through the valve is caused to change
direction _abruptly substantially at ninety degrees,
the fluid in the last form will change direction
pressure control oriilce 39in _a line 40. The- inner 75 y at an acute angle, vandtlne dynamic force ot the
_ 9,411,930
a valve member reciprocable in said bore closed
?uid will have an increased longitudinal com
at the end adjacent said pressure chamber and
ponent tending to close the valve.
formed with an axial bore opening to said spring
chamber and with peripheral ports opening to
I claim as my invention:
1. A relief valve comprising, in combination,
said last mentioned bore and movable in-to and
a valve body having a valve bore, a pressure inlet 5 out of communication with said iirst mentioned
opening to lthe side of said bore and a relief out
ports and radially inclined in the same direc
let. a pressure responsive valve member» recipro
tion as said inlet ports, coiled compression spring
cable in said bore and having a port in the pe
means disposed in said spring chamber and act
riphery movable into and out of communication
ing on said valve member to urge said member
with said inlet and a longitudinal bore closed at 10 in said one direction ¿toward closed position, pas
one end and establishing communication through
sage means ior directing fluid from said inlet
the other endbetween said port and said outlet,
ports to said pressure chamber to act on the l
saidbody being -formed with s, pressure chamber
closed end of said valve member in opposition to
f open Ato one end‘of said bore and a passage con
the force of said spring means and the kinetic
:necting said inlet to said chamber, said valve 15 energy acting in the direction of -the spring force
member having a pressure area at one end ex
generated by the fluid in said last mentioned bore,
posed to the pressure in said chamber, spring
and a balde at the inner endïeof said last men
tioned bore for directingeiluidfrom said last men
means acting on the other end of said valve
member in a direction to close said valve in op
position to said pressure, said port opening to 20
said longitudinal bore at an angle inclined ra
dially inwardly toward the closed end of said lon
gitudinal bore, and a baille in the closed end of
_tioned ports outwardly -toward said spring charn
4. A relief valve comprising, in combination, a
body having a valve bore opening at one end to
l a pressure chamber and at the other »end to a
said longitudinal bore for directing the fluid issu
spring chamber and formed with inlet ports ra
ingfrom said port through a sharp turn and then 25 diallyjnclined in one„direction longitudinally of
longitudinally out of said valve member «to said
said -bore, a valve_ member reciprocable in said
2. A relief valve comprising, in combination,
an elongated body having- a large bore in one end
and a small valve bore opening coaxially to the 3b
bore and formed with an axial bore opening to
opening to
chamber and with peripheral ports
said last mentioned bore and mov
into and out of communication with said
inner end of said large bore and having an outlet I .able
‘inletports and radially inclined in said one direc
passage opening from said large bore, the outer ---‘. tion, coiled compression spring means disposed
end of said valve bore deñning a pressure cham- " in said spring chamber and acting on said valve
ber and said valve bore being formed interme
memberr to urge said member in said one direc
diate its ends with an inlet port connected 35 tion »toward closed position. and passage means
through a restricted flow passage to said cham
for directing iluid from said inlet ports to said
ber, a branch passage opening from said inlet
pressure chamber to act on said valve member in
port in parallel with said restricted passage to
opposition to the force of said spring means and »
said chamber, a one-way check valve in said
the kinetic energy acting in the direction of the
branch passage for admitting iiuid to said cham- 40 spring torce generated by the fluid in the bore
ber, a valve member movable in said valve bore
valve member.
with a sliding fit and formed with a longitudinal . of 5.said
A relief valve comprising, in combination. a
passage opening to said\ large bore and with a
body having a valve bore opening at one end to
peripheral valve port opening to said longitudi- .
a pressure chamber and at the other end to a
nal passage, one end yof said valve member pre- 45. spring chamber and formed with a pressure inlet.
senting a closed end surface exposed to the pres
a valve sleeve fixed in said bore and formed with
sure in Vsaid chamber tending to move said 'valve
inlet ports in communication with said inlet and
member in a direction to bring said ports into
radially inclined in one direction longitudinalLv
communication, and a coiled compression spring
ci said bore, a valve member reciprocable in said
in said large bore acting on said valve member 50 sleeve and formed with an axial bore opening to
in a direction opposite to said first mentioned
said spring chamber and with valve ports open
direction, the kinetic energy created by the
to said `last mentioned bore and adapted Yfor
change of direction of flowthrough said valve
communication with said inlet ports and radially
member supplementing l’the pressure of said
inclined in said direction, coiled compression
spring to act on said valve member in opposition 55 ».springmeans disposed in said spring chamber
to the pressure in said chamber.
and acting on said valve member to urge said
3. A relief valve comprising, in combination, a
body having a valve bore opening at one end to
a pressure chamber and at the other end to a
member in said one direction. and a restricted
passage for directing fluid from said'inlet to said
spring chamber and formed with inlet ports ra- ¿o pressure chamber to act on saidl valve member
dially inclined upwardly and outwardly with re
spect to the pressure chamber end of said bore,
in opposition to the force of said spring means.
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