Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PRESSURE RELI EI~ VALVE
This application is a division of Canadian patent
application Serial No. 266,130 filed November 19, 1976.
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sackground of the Invention
1. Field of the Invention
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T.he present invention relates to safety vents or
valves useful with pressurized tanks which includes ruptura~le
valve members designed to relieve pressure occurring within a
tank or hopper at a predetermined PSI in order to protect the -
structural integrity of the unit to which it is connected.
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2. Description of the Prior Art .
The prior art is disclosed in U.S. patents
3,145,874, August 25, 1964 to Webb; 3,294,277, December 27, 1966 ~ ~.
to Wood; 3,526,336, September 1, 1970 to Wood; 3,685,686,
: ~ August 22,~ 1972 to Raidle; 3,797,511, March 19, 1974 to Selby;
: 3,834,581, September 10, 1974 to Solter et al; and 3,845,878,
November 5, 1974 to Carlson.
The present invention is an improvement over~the ~;
above patented structures.
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Summary of the Invention
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- The invention disclosed is particularly adapted -
to closed or covered hopper cars which are provided with
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pneumatic gate arrangements for unloading the car. In unloading
this type of car the gate is attached to a fluid pressure system
causing a subatmospheric pressure within the car whereupon the
material is discharged from the pneumatic gate usually to a
pres~urized conduit leading to a suitable storage bin or
reservoir. The safety vent in one embodiment of the disclosed
system includes a tubular housing which is connected to a pipe
extending vertically within the hopper car adjacent the roof
thereof for allowing the entrance of air through a filter
arrangement with which the safety vent is associated. The
safety vent may in one aspect include a rupturabLe valve or
diaphragm which at a predetermined subatmospheric pressure
within the car ruptuxes to alleviate the situation and protects
the structural lntegrity of the tank or hopper. The diaphragm
or valve comprises a rubber-like material which is stretched or
~ tensioned across the tubular wall of the housing in association
; with the tubular ring, which, when it ruptures, is destroyed
with the remains of the diaphragm receding or withdrawing
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substantially close to the inner wall oE the housing thereby
occupying a minimum of space area so that the flow of fluid
through the housing is not impeded in any way.
The invention to which this divisional
application is directed comprehends a safety vent for a covered
hopper car which has a hopper and a pneumatic discharge
mechanism ada~pted to be connected to a fluid pressure system for
material unloading. The vent includes a tubular member having a
tubular wall providing a passage therein, one portion of the
wall being connected to andcommunicating with the interior of
the hopper car and a second portion of the wall communicating
with the atmosphere. A valve member is rupturable at a
predetermined design pressure supported on the tubular member
between the tubular portions to block 1uid flow through the
tubular member. The valve member is a balloon-like element
expanded within the member and includes a stretchable diaphragm
stretched transversely across the tubular wall which, upon
rupture of the member, torn portions of the diaphragm recede in
a radially outward direction toward the tubular wall so as not
to impede the fluid flow therethrou~h.
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- -: Brief Description of the Drawings
FIG. 1 is a side elevational view of a
hopper car having portlons of the same broken away to
illustrate an improved filterlng end vent system;
FIG. 2 is a cross-sec tional view taken
substan~lally along the line 2-2 of FIG. l;
FIG. 3 is a cross-sectional view taken
subs~antially along the line 3-3 of FIG, 2;
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FIG . 4 is a view s imilar to FIG. 2 dis-
closing the condition of a rupture valve or diaphragm,
: appearing with Figs. 1 and 2; and
` - , FIG. 5 is a cross-sectiollal vl~w slmi-
- - lar to FIG. 2 disclosing a modified diaphragm struc-
: ture.
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Description of the Pre~erred ~mbodiment
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; ~ - Fig. 1 dlscloses a closed hopper car
10 having conventlonal stub center sllls 11 at oppo-
site ends ~hereof wh~ch.are supported on conventional~
whe~l ~rucks 12. The car 10 includes a car body 13
having ver~ical car sides 14 and sLopin~ end ~alls
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or sheets 15 connected to the car sides 14. The
slope sheets or end walls 15 with intermediate slope
sheets or walls 16, comprise and form a total of four
separate hoppers 17 which are adapted to contaln bulk
material such as plastic pelle~s etc. The hopper car
10 is of the closed type and includes conventional
pneumatic discharge gates 18 attached to each of the
hoppers 17 at their lower ends thereof ~he same in-
cluding capped discharge tubes 19 which during un-
102ding are uncapped and connected to a suitablefluid pressurized system for unloading and conveylng
materials from the car.
The car-10 comprises a roof structure
20 including a plurality of longitudinally spaced hatch
covers 21 whlch are removable for ov~rhend loadltl~ pur-
poses. The vent systcm or arrangement 22 comprises
a filter 23 cons~sting of a tubular body or housing
:' member 24 connected-to a vent pipe 25 which ~xtends
upwardly withln the car through one o~-the hopper ~alls ~:
terminating at its upper end in an opening 26 adjacent
the roof structure. Tle tubular body and housing member
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24 and p$pe 25 are suitably supported on a central
part~tion wall 27 and hopper wall 16~ sub~tantlally
centrally on the body and below ~hereof thus providing
ready access to the operator for servlcing the unit.
The car also ~ncludes two other partition walls 27 thus
dividing the car into the four hopper uni~s a~ described.
The present invention relates to ~ safety
valve or vcnt system 28 which is positioned at the upper
end of the tubular`body or housing member 24. Referring
particularly to FIGS. 2, 3 and 49 the vent 2B is provided
at the upper end of the tubular body or housing member
24 which ~ncludes a vertical inner tubul~r wall 29. The
wall 29 is ~ro.vided at its upper end w~th a 1ange 30.
which is connected by means of nuts and bolts 339 to a
- collar 31 having a flange 32. The collar 31 also ln-
- cludes an inner tubular wall 34 in registry with the
wall 29. The upper end of ~he c~llar 31 is provided
w~th an annular undercut seat 35. The outer.circum-
ferential surface of the collar 31 includes circumfereno
, 20 tially spaced lugs 36 having outwardly directed arcuate
. ~ indentations 37. The safety valve system 28 includes a
cap 38 which m~y be hingedly remosred to an opened position
for service reasons that will be presently described.
The collar 31 includes outstanding ears 39 and a hlnge
br~cket 40 on the cap 38 is hingedly connec ted thereto
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by ~.eans of a hinge pin 41. A latch bolt 42 is pivotally
connected to hinge ears 43 supported on the collar 31
and is adapted to enga~e in locked relation split latch
lu~s 44 held in this position by means of a nut 45.
FIGS. 2, 3 and 4 disclose a valve assembly 46 comprising
a ri~d ring 47 havin~ a di~phragm 48 connected thereto.
The diaphra~m 48 comprises a rubber-like material which
is stretched across the rin~ and ;s securely fastened
thexeon by me~ns of a wrapped and glued connection
portion 49 enclosin~ the rin~ 47. ~hile a rubber material
is disclosed~ any ma,teria,l which has a high resiliency
and wh.~ch when ruptured will recede or diminIsh sub- ' :.
sta,ntially in length~ can be utilized. The ring 47
a5 disclosed i,n FIGS. 2, 3 and 4, is removably seated
upon the annular undercut seat 35. As best shown in .'
: FIG~, 2 a~d 5, ~ conventional knife or p~ercing element
s 50 i$ d;~sposed immediately below the valve 46. As can
be seen in Fi~ure 2~ the valve assembly includin~ ring -'':
47 and diaphragm 48 is solely seated upon the surface of
.,20 a,n~ula,~ undercut seat 35~ The vertical space between the
vertical surface of the ring and diaphragm (~7,48~ and
the opposin~ vertical wall member.31 allows the ring and ~ .
diaphragm to be displaced from the seatin~ surface such as ~ ~,
i~ there ~ere a sudden increase in pressure in the car.
FIG~ 4 discloses the condition of the diaphragm 48 ',
afte~ it has ruptured whereiin the stretched or pretensioned
condLtion of the diaphragm results in the shredded or
destroyed remainin~ pieces 51 havin~ receded or withdrawn
outw~xdly against the wall 34 thus permittin~ the uninterrupt~
, 3Q ed or unimpeded ~low of air therethrough.
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In the m~dification of ~IG. 5, the ring
47 supports a diaphragm 52 which comprises a circumfer-
en~i~l vertical wall 53 integral wlth p~rallel spaced
walls 54 one of wllich is provided wi~h an inflating
closure 55. The diaphragm 52 here again i5 of a rubber-
like material and is held ~nan inflated cor~dition against
the ring 47 and which when ruptured it i~ substant~ally
destroyed with ~he pre-stre~ched conditlon of the dia-
phragm c~using only fragm2n~s to re ~ in after destruction
10 so that agaih the air can frcely travel through the
tubular wall`29 to the hopper.
~ration
In the uncapped posit~on of the pneu~tic
clischarge gates 18 a fluid pressure sys~em is connected
- thereto and the m~terial is withdrawn fro~ the hoppers ~ :
by suction to unload the same. Alr enters through the
filter 23 through the tubular body 24 and is discharged
into ~he upper ends of the hoppers so that the ~terial
~ is discharged and flows freely through the pneumatic
. gates. The maximum sub-atmospheric pressure within the
car durLng pneumatiC unloadlng is one-half PSI and any
sub-a~mospheric pressure below this figure causes the
diaphragm 48 to be dra~n b~ suction against the knife
edge 50 ~hereby rupturing the diaphragm and permitting
`~; the entrance of air through the housing and pipe lnto
.: the carO Thus, the safety vent guarantees that any
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malfunction of the filter or air co~ing therethrough which
if impeded in any way will permit air to enter into the car
when the diaphragm is ruptured thus assuring that the walls
of the car cannot be inadvertently collapsed because of
the lowering of the sub-atmospheric pressure below one-
half PSI.
It will also be noted that by virtue of the fact
that the ring and diaphragm are solely seated upon the
seating surface 35, they are displaceable upwardly from the
seating surface such as if there were a sudden increase in
pressure in the car as might occur when lading shifts or
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temperature changes. However, when the pressure in the car
is reduced during unloading, the valve assembly of the ring
47 and diaphragm 48 will be positioned against the seat 35
and held there solely by the reduction in pressure in the
car.
In the prior art ahove described, and generally in
the field of safety vents, many different types of rupturable
diaphragms or discs have been provided. These generally
~20 have consisted of material such as paper, aluminum, plastic,
etc. and will function well particularly in tank cars wherein
high pressures are encountered and where the ruptured material
is subjected to said high pressures so that the flow of
fluid through the tubular housing is not generally impeded.
However in the utilization of hopper cars which are
placed under a sub-atmospheric pressure of at least one-
hal~ PSI, difficulties with the diaphragms of the
prior art have been encountered. The paper or plastic
disc in sub-atmospheric pressure utilization would par-
tially rupture when encountering the knife edge 50.However the blade would provide a center support ~or the
disc to prevent the disc from completely rupturing at
the maximum pressure permitted in the car. As a result,
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at the low pressure, the disc would remain supported
in position across the tubular wall substantially
impeding the flow of air through the housing to relieve
the pre~sure withln the hopper car. In the present
invention, the seretched rubber having stored up
energy due to the stretching, comple~ely ruptures
wlth the destroyed condition of the diaphragm being dls-
closed in FIG.4~ wherein the fragments 51 have receded
exposing substantially the entire throat opening of
the collar 31 and providing for the free flow of air
through the housing walls 29. .Thus for the type of
operation of a hopper which is pneumatlcally unloaded
the s ~ruc ture of the present invention provides A
diaphragm which will functlon to ensure adequate safety
protection.
. In FIG. S a modified valve 46 includes
; a balloon-like diaphragm 52 which is inflated and
; which is tightly held aga~nst the inner clrcum~erence
of the r~ng 47. Upon rupture the balloon will collapse
bec~use of the pre-stretched, or tensioned rubber
material, and the fragmentary elements remaining will
not substantially prevent the inflow of air tbrough
the collar 31 and tubular member 24. The inflated
balloon diaphragm may be suitably attached to the inner
clrcumferential wall of the rlng 47 so that the fragments
remain with the rin~ after rup~ure or if desired the
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lnflation of the dlaphragm 52 is sufficient to m~in~ain
its position ~ightly against the inner surface of the
ring 47 and when ruptured i~ will dlsintegrate into
shreds which are removed through the tubular member
29 and are discharged with the material.
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The cap 38 of course can be easlly re-
moved for replacing any ruptured diaphragm and is
eas~ly placed ~n posit~on on the annular lugs 36 of
the collar 31~
The foregoing descr~ption and drawings
- merely explain and illustrate the lnvention and the
invention is not limited thereto, except lnsofar as
the appended claims are so lim~ted, as those skilled
in t~e art who have the disclosure before them will
be able to make modifications and variations therein
without d~parting from the scope of the invention.
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