close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3097677

код для вставки
July 16, 1963
I
o. s. ANTRIM ETAL_
3,097,555
CHECK VALVE
2 Sheets-Sheet ' 1
Filed Dec. 11, 1959
'
IN VE'NTORS
DORON $- ANTR/M
NELSON G- KL ING
J< VINCENTA- GILL
g?"
5
'
R/CHEY, MSNE'NNYJ‘FARRINGTM
ATTO NEYS
July 16, 1963
o. s. ANTRIM ETAL
3,097,666
CHECK VALVE
Filed Dec. 11, 1959
2 Sheets-Sheet 2
.
w
62\ I
X\64
36
INVENTORS
DO/PON s. A NTR/M)
NELSON a. KAI/VG
3/2951?
,24
BY
& VINCE/V7’ A - 6/“
48
I? lC HE Y, MENEIVN >2 F4 RIP/N670”
I 46
A TTOR/VEYS
United States Patent 0
_
3,097,666
TI
C6
Patented . July 16, 1963
1
2
3,097,666
open, yet provides a lip seal action when the valve is closed
whereby the pnessure being sealed against is utilized to
CHECK VALVE
Doron Anti-1m, Gar?eld Heights, and Nelson G. Kling,
Euclid, Ohio, and Vincent A. Gill, Montclair, N.J., as
srgnors to The Weatherhead Company, Cleveland,
Ohio, a corporation of Ohio
Filed Dec. 11, 1959, Ser. No. 858,946
5 Claims. (Cl. 137-5155)
aid in the sealing action.
According to a preferred embodiment of the present in
vention, the valve seat is a smoothly ?nished conical sur
face fonmed on the metal valve body. The seal comprises
a sheet of rigid plastic material, such as polyethylene
terephthalate, which is carried by a metallic poppet also
conical in shape. The sheet seal extends radially outward
This invention relates to check valves, and more par
across the midsection of the poppet to the outer conical
ticularly to seals for check valves adapted for use over
surface of the poppet, from which point it extends for a
a wide temperature range.
spaced distance both radially and axially forward along
Present day developments in such ?elds as aircraft and
the surface of the poppet. It is an advantage of this
missiles have made increasingly severe demands on the
design that the plastic material for the seal is preferably
performance of fluid pressure systems and their compo
15 chosen as to have a thermal coe?icient of expansion on
nents. Among the many problems encountered in the
the same order as that of the metal used for the poppet.
design of the components for such ?uid pressure systems
The portion of the conical surface of the poppet which un
is the requirement that they operate e?iciently and reliably
derlies the axially extending portion of the seal has a more
at high ?uid pressures over an increasingly Wide range of
acute apex angle than the angle of the conical surface
temperatures. Because of extreme changes and rapid 20 of the valve seat. The plastic sheet is of relative constant
?uctuations of environmental conditions, components are
thickness at all points, and thus when the poppet is
often required to operate not only at considerably ele
seated with the axially rearward portion of the seal in
vated temperatures, but also at very low temperatures.
abutting contact with the valve seat, the forward or outer
To meet the requirements of wide temperature range
end of the seal is free to move a short distance radially so
pressure systems, the check valve seal must be effective to 25 that back ?uid pressure lifts the forward portion of the
prevent reverse ?ow leakage at both the high temperature
seal away from the surface of the poppet and ‘forces it
range and the low temperature range. The problem of
outwardly against the surface of the valve seat. The
leakage past the seal has been particularly acute in the
case of ?uids such as gaseous helium, which is notorious
back pressure thus provides a lip sealing action by forcing
the seal into contact with the valve seat along the length
for the leakage problem which it creates. Because of 30 of that portion of the seal which extends forward along
its low viscosity and small molecular size, a seal which
the conical surface of the poppet. The greater the magni
might be effective when used with other fluids has an
tude of the back pressure, the more tightly the seal is
objectionable leakage rate when used with helium.
forced against the valve seat to resist the leakage of ?uid
While check valves have been made with a Wide variety
between the seal and the seat.
of constructions, one of the most widely used arrangements
Other features and advantages of this invention will be
is that in which a spring loaded poppet moves axially
come apparent to those skilled in the ‘art upon a more com
along the path of ?uid ?ow and is spring loaded into con
plete understanding of the invention of which an embodi
tact with a valve seat. This general arrangement has
ment is shown’ in the ‘drawings and described in the fol
many advantages such \as compactness and simplicity in
lowing detailed description.
the number of parts, as well as being readily adaptable 40
In the drawings:
to insertion between sections of ?uid pressure conduit.
FIG. 1 is a longitudinal cross-sectional view of a check
To obtain an effective seal between the poppet and the
valve incorporating the invention before its assembly has
valve seat, it has often been found necessary to make a
been completed;
portion of the sealing members out of a soft, resilient, de
FIG. 2 is a longitudinal cross-sectional view of the
foumable material such as rubber. However, these seal 45 valve shown in FIG. 1 after it has been completely assem
ing members are not effective throughout a wide tempera
bled and showing the valve in the closed condition;
ture range. A rubber material which is soft enough to
FIG. 3 is a longitudinal cross-sectional view similar to
seal effectively at low temperatures, fails at high tempera
FIG. 2, but showing the valve in the open position;
tures due to excessive softening of the material so that
FIG. 4 is a cross-sectional view taken on lines. 4——4 of
under high pressure the material tends to cold ?ow and 50 FIG. 2 to show the poppet guide in greater detail;
extrude out of the seal area. On the other hand, a rub
FIG. 5 is an exploded longitudinal cross-sectional view
ber material which is strong enough to resist this cold
of the component parts of the poppet assembly;
flow at high temperatures becomes brittle and cracks at
FIG. 6 is a longitudinal cross-sectional view showing
low temperatures. The use of deformable materials with
the poppet in position in the tool which is used to form
greater temperature stability such as polytetra?uoro 55 the seal;
.
ethylene and silicones have also extended the useful tem
FIG. 7 is an enlarged longitudinal cross-sectional view
perature range only slightly.
These materials have a
rate of thermal expansion which is much greater than
that of the metals which are used for the valve bodies
of the poppet as completely ‘assembled; and
FIG. 8 is a fragmentary cross-sectional view showing
details of the seal construction.
and poppets, so that when they are used ‘outside of a 60
Referring now to the drawings, the valve has a body
limited temperature range, the seal parts made from these
of two piece construction comprising a forward section
materials become so distorted as compared to the metal
10 and a rearward section 11. As used herein, the for
seal parts that an effective seal is no longer possible.
ward direction is the direction in which ?uid flows
An object of this invention has been to provide a check
freely through the valve. The outer end of each of these
valve having a valve poppet seal that is effective to prevent 65 sections has an externally threaded portion 12 and an
leakage of pressures throughout a wide temperature range
internally recessed portion‘ 13 of appropriate size and
from very low temperatures to considerably elevated
shape to receive tube ?ttings in the usual manner. Each
temperatures.
of the body sections is also formed with an enlarged
Another object of this invention has been to provide a
wrench-receiving portion 14 having holes 15 through
valve seal for a check valve which produces a minimum of 70 which lock wires can be passed after the check valve
turbulence and resistance to ?uid ?ow when the valve is
has been assembled.
3,097,666
3
Each of the body sections is provided with a series
ness as the rest of the seal and which extends forward
of concentric bores to receive the remainder of the valve
structure. The forward section 10‘ has four cylindrical
along the conical surface 43 of the poppet.
The shape and operation of the seal 50 can be under
stood more ‘clearly in the light of a preferred method of
bores 16, 17, 18, and 19, each of which respectively has
a greater inner diameter.
The rearward section 11 has
three cylindrical bores 20, 21, and 22, of which the mid
dle bore 21 is the largest. These three bores are inter
connected by conical surfaces 23 and 24, the latter
forming the seal and assembling it with the poppet 35
and seal retainer 46. The seal is cut or punched out of
\a thin, smoothly ?nished sheet of plastic material, pref
erably of a polyester plastic such as polyethylene tereph
thalate. The cut disc is then baked at an elevated tem
conical surface having a very smooth surface ?nish and
perature of about 300° F. to 325° F. to relieve the in
serving as the valve seat, as will be described in greater
10 ternal stresses formed in the manufacture of the sheet
detail‘ hereinafter.
and the cutting of the disc. A disc made of polyethylene
In order to fasten the two body sections together, the
rearward bore 19 in forward section 10 is provided with
terephthalate also shrinks between 3% and 5% in size
internal threads 25 which are engaged by suitable ex
as a result of the heating, but it becomes stabilized after
ternal threads 26 on the front end of the rearward body
this initial heating and will not change in size thereafter
section 11. In front of the threads 26 is a reduced 15 even when re-exposed to the same temperature. The
seal is then placed between the poppet 35 and the seal
annular sleeve 27 having bore 22 as its inside diameter
retainer 46 which are then pressed together in a press,
and having an outside diameter to ?t within the bore
after which operation the poppet, the seal, and the re
18 in forward section 10. In order to seal against leak
tainer form an integral unit by virtue of the interference
age at the joint between the two body sections, an an
20 ?t between the stem 45 of the seal retainer and the bore
nular gasket or crush washer 28, formed of a suitable
44 of the poppet. The pressure used in assembling these
material such as polytetra?uoroethylene, is ?tted over
parts must be su?iciently high to cause part of the seal
the annular sleeve 27. When the two body sections are
material to ?ow into the annular groove 53, but not so
screwed together, the crush washer 28 is enclosed within
high as to cause any additional plastic ?ow and extru
an annular chamber bounded radially by bore 19 and
sleeve 27 and axially by radially extending annular sur 25 sion of the seal from the space between the annular
faces 51 and 52.
faces 29 and 30 on the body sections 10 and 11, re
The annular lip portion 54 is formed on the seal 50 with
spectively. These annular surfaces 29 and 30 each have
the use of the tool shown in FIG. 6. This tool comprises
annular serrations 31 which are forced into the crush
a cup 60 having an axial bore 61 and a poppet receiving
washer as the latter is compressed to cause high localized
seat 62 through which the poppet stem 36 can extend. A
stresses within the washer which increase the effectiveness
plunger 63 is made to slide within the axial bore 61 and
of the sealing action.
has a cap portion 64 to which pressure ‘may be applied.
The valve poppet 35 has a forwardly extending stem
Plunger 63 also has an axial bore 65 which serves as a
36 which is a sliding ?t within the rearward extending
tubular portion 37 of the guide 38. To stabilize and 35 vent for air entrapped within the cup, and which at its
inner end opens onto a smoothly ?nished conical surface
position the guide 38, three narrow, symmetrically spaced
66 having an included apex angle of 60°, making it con
legs 39 (see also FIG. 4) project radially outward from
forma‘ble in shape to the valve seat 24. The tool is then
the forward end of the guide to contact the sides of bore
placed in a press and the plunger 63 forced toward- the
17 to position the guide radially, the spaces between the
legs allowing ?uid ?ow past the guide. The legs 39 also
assembled poppet so that the conical surface 66 forces the
abut against shoulder 40 formed at the junction of cylin
projecting rim of the seal 50 back over the conical poppet
drical bores 16 and 17 to position the guide axially. A
surface 43 to form the annular lip 54 with su?icient pres
coil compression spring 41 is ?tted around stem 36
sure to cause cold ?ow of the seal material and give a
and tubular portion 37 to abut at the ends on the guide
permanent set to the annular lip 54. The seal 50 after
legs 39 and the poppet 35 to bias the poppet normally 45 cold forming may be described as an apertured ?anged
rearwardly into the closed position to contact the conical
disc having the ?ange or lip portion 54 thereof angularly
valve seat 24.
disposed with respect to the disc clamped between mem
bers 35 and 46,
The details of the construction of the poppet 35 are
shown in greater detail in FIGS. 5 and 7. The poppet
The operation of the assembled check valve and of the
head is formed with two oppositely extending conical 50 seal 50 is shown most clearly in FIGS. 2, 3, and 8.
surfaces 42 and 43. The forwardly extending. conical
Whenever the ?uid pressure in inlet bore 20 is greater
surface 42 is formed to minimize turbulence and has an
than that in outlet bore 16 and sufficient to overcome the
included apex angle in this case of about 34°. The
resistance of the spring 41, the poppet moves axially for
other conical surface 43 extends rearwardly and has ‘an
ward, as shown in FIG. 3, to leave a clear and relatively
included apex angle of 50° for reasons given in detail 55 unrestricted passage for ?uid ?ow around the poppet and
hereinafter.
through the check valve in the forward direction. When
The rearward end of the poppet has an axial bore 44
the check valve closes, as deter-mined by the ?uid pressure
to receive the cylindrical stem 45 of the seal retainer 46.
in outlet bore 16 being higher than the ?uid pressure in
The seal retainer 46 has an enlarged head 47 with an
inlet bore 20, the poppet moves axially rearward until the
outer conical surface 48 having ‘an included apex angle 60 annular lip 54 of seal 50 comes into abutting contact with
of 60°, the same angle as that of the valve seat 24. An
the valve seat 24 to close and seal the valve against re
axial bore 49 passes through the seal retainer 46 for the
verse ?uid ?ow.
purpose of allowing entrapped air to escape from the
As is shown most clearly in FIG. 8, since the valve seat
chamber formed by bore 44 when the seal retainer is
surface makes a 30° angle with the axis of the valve while
pressed into place in the poppet during assembly. The 65 conical surface 43 makes only a 25° angle with the axis,
seal 50 is in the form of an annular disc which is
there exists a wedge shaped clearance space indicated at
clamped between radially extending annular faces 51
55 between the under surface 56 of lip 54 and the conical
and 52 on the end of poppet 35 and on seal retainer .46,
surface 43. This clearance space provides a lip sealing
respectively. The end face 51 of the poppet is provided
action by allowing the ?uid pressure to act on this under
with an annular groove 53 into which the seal is ex 70 surface 56 and force the annular lip 54 outward and into
truded when the poppet is assembled to aid in clamping
abutting contact with the surface of the valve seat 24
the seal against radial movement out of the space be
along the entire length of the outer surface 57 of the lip.
tween the annular faces 51 and 52. The seal 50‘ projects
The greater the ?uid pressure applied to the under sur
outward beyond the conical surfaces 43 and 48, and
face 56, the greater is the contact pressure between the
has an annular lip portion 54 of about the same thick 75 outer surface 57 and the valve seat. Thus lip 54 acts as
3,097,666
a lip seal inasmuch as the sealing pressure between the
sealing surfaces 57 and 24 becomes propontionately
greater as the ?uid pressure to be sealed against increases.
It will be noted that no portion of the surfaces of the
poppet 35 or the seal retainer 46 comes into contact with
the valve seat 24, but that sealing contact is made solely
between the annular lip 54 and the valve seat. By having
parts without impairment of the reliability and ef?ciency
of the valve.
If the valve seat expands or contracts a
greater amount than do the poppet, seal retainer and seal,
a sealing ?t will be made by the poppet assembly at a
‘greater or lesser depth on the conical valve seat surface
so long as the valve seat is not distorted out of its proper
conical shape.
Although only one embodiment of the invention has
been shown and described, it is understood that the valve
but ‘a clearance space between the valve seat 24 and the 10 structure may be modi?ed and different materials sub
stituted for the various valve parts as required for dif
conical surfaces 43 and 48 of the poppet and the seal re
ferent operating conditions without departing from the
tainer is maintained at all times to allow for the different
scope of the invention as de?ned in the appended claims.
rates and amounts of thermal expansion ‘on the part of
What is claimed is:
the poppet 35 and seal retainer 46, ‘as compared to that
=1. A valve comprising a body, a conical valve seat on
of the rearward body section 11 on which the valve seat
said body, said valve seat ?aring rearwardly from a re
is formed.
duced diameter portion :at the forward end to an enlarged
When the valve poppet is in the open position, the pro
diameter portion, an axially movable poppet in said body
truding seal lip produces very little turbulence in the for
coaxial with said valve seat, a radial face and an annular
ward ?uid flow, since by virtue of its thinness it projects
conical face on said poppet, said radial poppet face having
only a small distance above the conical surfaces 43 and 20 a diameter intermediate those of the reduced and enlarged
48 as compared to the distance between the outer surface
portions of said valve seat, said conical poppet face having
57 of the lip and the valve seat 24. Any tendency on the
an apex angle less than that of said valve seat, a seal re
part of eddy currents in the ?uid to lift up the annular
tainer having a radial ‘face opposed to said ?rst-named ra
lip 54 during forward ?uid ?ow as a result of such eddy
dial face secured to said poppet, and a centrally perforated
currents ?owing rearwardly into the clearance space 55 25 annular sealing member of resilient sheet material secured
is overcome by virtue of the permanent set imparted to
between said poppet and said retainer, said sealing member
the annular lip 54 which gives it sufficient rigidity and
extending across the radial face of said poppet to said con
stiffness to prevent any such lifting action.
ical poppet face, said sealing member having a rearwardly
An example of a check valve constructed in accordance
extending conical lip portion ‘adapted to sealingly engage
with the present invention employs stainless steel for the 30 with said conical valve seat, the rear-ward end of said lip
body sections 10 and 11 to provide corrosion resistance
being spaced away from said conical poppet face and in
against environmental conditions. Both the poppet 35
contact with said conical valve seat when said poppet is in
:and the seal retainer 46 are made from a heat treated
the closed position with the ‘forward end of said conical lip
high strength aluminum alloy. Since such an aluminum
compressed between said poppet and said valve seat with
alloy has a thermal coefficient of expansion on the order 35 said poppet and said retainer being spaced away from said
of 12.6>< lO-‘i/ °F., a seal made out of polyethylene ter
valve seat at all points.
ephth-alate which has a coefficient of expansion on the
2. A valve comprising a body, a conical valve seat on
order of 15><1O'6/° R, will expand and contract at ap
said body, said valve seat ?aring rearwardly from a re
proximately the same rate as the aluminum poppet and
duced diameter portion at the forward end to an enlarged
seal retainer. Such a valve construction has provided an 40 diameter portion, an axially movable poppet in said body
efficient and reliable check valve operating over a range
coaxial with said valve seat, a conical face on said poppet,
of ambient temperatures from —320° F. to +160° F.,
the apex angle of said conical poppet face being more
and ‘for brief periods at temperatures as high as 450° F.,
acute than the apex angle of said conical valve seat, a seal
when used with gaseous helium as the fluid medium at
retainer secured on the end of said poppet adjacent said
45
pressures ranging as high as 6,000 psi, although a pres
valve seat, said seal retainer having a conical face extend
sure of only 10 psi. is sufficient to open the poppet and
ing parallel to said conical valve seat and spaced there
allow full flow in the forward direction.
from, and a sealing member of resilient sheet material
It has been found that if the seal is made of a material
secured between said poppet and said retainer, said sheet
which has :a thermal coefficient of expansion which is
material extending radially outward between said poppet
50
more than 1.5 times ‘greater than that of the metal used
and said retainer to said conical poppet face and said
for the poppet and seal retainer, the higher rate of ther
conical retainer face, said radially extending portion of
mal expansion of the seal causes it to wrinkle and buckle
said sealing member having a diameter intermediate those
between the poppet and seal retainer when the valve is
of the reduced and enlarged portions of said valve seat,
exposed to temperatures ranging toward the upper of the
said sheet material extending rearward-1y and outwardly
above-mentioned extremes. Similarly, at low tempera
between said conical poppet face and said conical valve
tures the greater rate of thermal contraction of such a
seat to provide a pressure assisted lip seal against said
seal creates a gap between the seal and the end face 51.
valve seat when said poppet is in the closed position with
Both the wrinkling and buckling of the seal and the gap
the forward end of said conical lip portion compressed
cause leakage by creating a leakage passage around the
between said poppet and said valve seat.
60
seal between the retainer and the poppet so that under
3. A valve comprising a body, a conical valve seat on said
these conditions the sealing effectiveness of such a seal
body, said valve seat ?aring rearwardly from a reduced
material will fall below requirements of the speci?cation
diameter portion at the forward end to an enlarged diam
for the valve. Siuce polyethylene terephthalate has a
eter portion, an axially movable poppet in said body
thermal coef?cient of expansion of only about 1.2 times
coaxial with said valve seat, a conical face on said poppet,
65
that of the aluminum alloy, this particular combination
the apex angle of said conical poppet face being more
of materials avoids this sealing problem, but it is under
acute than the apex angle of said conical valve seat, a
stood that other combinations of materials having the
seal retainer secured on the end of said poppet adjacent
ratio of their thermal coef?cients of expansion
the
said valve seat, said seal retainer having a conical face
limit of 1.5:1 may also be used.
extending parallel to said conical valve seat and spaced
It should be noted that the effectiveness of this poppet 70 therefrom, and a sealing member of resilient sheet mate
construction over a wide temperature range does not de
rial of uniform thickness secured between said poppet and
pend upon the thermal coe?icient of expansion of the
said retainer, said sheet material extending radially out
material used for the valve seat, and such materials as
ward between said poppet and said retainer to said conical
stainless steel, which has a thermal coefficient of expan
poppet face and said conical retainer face, said radially
75
sion about half that of aluminum, may be used for such
contact at these points only, not only is a higher unit pres
sure obtained between the seal 50 ‘and the valve seat 24,
7
3,097,666
extending portion of said sealing member having a diam
eter intermediate those of the reduced and enlarged por
tions of said valve seat, said sheet material extending rear
wardly and outwardly between said conical poppet face
and said conical -valve seat for a distance less than the
valve seat, guide means for said poppet, spring means
resiliently biasing said poppet toward said valve seat, a
conical face on said poppet adjacent said valve seat, the
apex angle of said poppet face being more acute than the
apex angle of said conical valve seat, a seal retainer se
length of said conical poppet face to form a conical lip»
cured on the end of said poppet adjacent said conical
portion, the outer end of said sheet material being a
poppet face, said seal retainer having a conical peripheral
spaced distance from said conical poppet face to provide a
face extending parallel to said conical valve seat and
pressure assisted lip seal against said valve seat when said
spaced therefrom when the check valve is closed, and a
poppet is in the closed position with the forward end of 10 sealing member ‘of resilient sheet material of uniform
said conical lip portion compressed between said poppet
thickness secured between said poppet and said seal re
and said valve seat.
tainer, said sheet material extending radially outwardly be
4. A ‘check valve comprising a body, said body having
an inlet and an outlet and a chamber therebetween, a
tween said poppet and said retainer to said conical pop
pet face and said conical retainer face, said radially ex
conical valve seat on said ‘body between said chamber 15 tending portion of said sealing member having a diameter
and said inlet, said valve seat ?aring rearwardly from
a reduced diameter portion at the forward end at said
inlet to an enlarged diameter portion at said chamber, an
intermediate those of the reduced and enlarged portions
of said valve seat, said sheet material extending rear
wardly and outwardly between said conical poppet face
axially movable poppet in said chamber coaxial with said
and said conical valve seat for a distance less than the
valve seat, a conical face on said poppet adjacent said 20 length of said conical poppet face to form a conical lip
valve seat, the apex angle of said conical poppet face
portion providing a pressure assisted lip seal against said
being more acute than the apex angle of said conical
valve seat when said poppet is in the closed position with
valve seat, a seal retainer secured on the end of said
poppet adjacent said conical poppet face, said seal re
tainer having a conical peripheral face extending parallel 25
to said conical valve seat and spaced therefrom when the
check valve is closed, and a sealing member of resilient
sheet material of uniform thickness secured between said
poppet and said seal retainer, said sheet material extend
ing radially outward between said poppet and said re
tainer to said conical poppet face and said conical re
tainer face, said radially extending portion of said seal
ing member having a diameter intermediate those of the
reduced and enlarged portions of said valve seat, said
sheet material extending rearwardly and outwardly be 35
tween said conical poppet face and said conical valve
seat for a distance less than the length of said conical
poppet face to form a conical lip seal portion providing
a pressure assisted seal against said valve seat when said
poppet is in the closed position with the forward end of 40
said conical lip portion compressed between said poppet
and said valve seat.
5. A check valve comprising a body, said body having
an inlet and an outlet and a chamber therebetween, a
the forward end of said conical lip portion compressed
between said poppet and said valve seat.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,863,712
2,257,209
2,307,546
2,482,198
By?eld ______________ __ June 21,
Wells ______________ __ Sept. 30,
Shimer _______________ __ Jan. 5,
Melichar ____________ __ Sept. 20,
2,544,209
Wolcott ______________ __ Mar. 6, 1951
2,674,032
2,722,232
2,772,695
2,820,604
2,823,006
2,886,283
2,918,083
2,938,533
2,949,928
2,960,998
2,980,388
3,055,391
Martin ______________ __ Apr. 6, 1954
Roche _______________ __ Nov. 1, 1955
Harrison _____________ __ Dec. 4, 1956
Ray _________________ __ Jan.
Hare _______________ __ Feb.
Natho ______________ __ May
Clark _______________ __ Dec.
Jensen ______________ __ May
Hobson _____________ __ Aug.
Sinker ______________ __ Nov.
White ______________ __ Apr.
21,
11,
12,
22,
31,
23,
22,
18,
1932
1941
1943
1949
1958
1958
1959
1959
1960
1960
1960
1961
Shur _______________ __ Sept. 25, 1962
conical valve seat on said body between said chamber 4.5
and said inlet, said valve seat ?aring rearwardly from
OTHER REFERENCES
a reduced diameter portion at the forward end at said
‘ Mylar Technical Report, E. I. du Pont \de Nemours &
inlet to an enlarged diameter portion at said chamber,
Co. (Inc), ‘Wilmington, Delaware, August 1956. (Copy
an axially movable poppet in said chamber coaxial with
in Div. 60.)
Документ
Категория
Без категории
Просмотров
0
Размер файла
888 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа