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Патент USA US3061331

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Oct. 30, 1962
P. F. SMITH
3,061,321
DOUBLE CONTACT FLUID SEAL
Filed July 15, 1957
//
INVENTOR.
PAUL 5 5M/7'H
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United States Patent O?ice
1
3,061,321
Patented Oct. 30, 1962
2
openings are placed to enter the cavity at a position con
3,061,321
DOUBLE CONTACT FLUID SEAL
tacting the projection-forming portion of the mold, ?ash
is normally formed along the top of the projection which
must be accurately trimmed from this sealing surface. As
Paul F. Smith, Paci?c Palisades, Calif., assignor to Parker
Hanni?n Corporation, Cleveland, Ohio, a corporation Cl an alternative, the sprue opening may be formed to cause
of Ohio
the plastic-state material to enter the cavity through sprue
Filed July 15, 1957, Ser. No. 671,795
openings between the location of the projection in the
3 Claims. (Cl. 277-180)
resilient member, and the edge or wall of the rigid retain
This invention relates to sealing means and particu
ing body. However, in the event that this mode of injec
larly to improved ?uid seal for use between mating sur 10 tion is used, the sprue openings must be very small and
faces.
the injection pressures must be quite high.
To provide a pressure seal between mating surfaces, it
With the foregoing in mind, the present invention con
has previously been common practice to insert a layer of
templates positioning a resilient deformable packing mem
deformable packing material which is compressed when
ber having a pair of projections within a groove of a rigid
retaining body each of which establishes sealing contact
the surfaces are mated. However, seals formed in this
manner are incapable of withstanding high pressure, and
with an opposed mating surface. A single channel is
the packing material may be used only once. To over
formed in the packing member between the two projec
tions. When the device seals with mating surfaces which
come these difficulties, various improved sealing means
have been developed. One such improved means includes
are drawn together, the two projections are deformed to
a groove in one mating surface which is ?tted with a resili
lie within the single channel.
ent deformable packing member. The deformable mem
Any void space remaining within the groove lies be
ber is then deformed to lie entirely within the groove
tween the two projections and as this space becomes ?lled
when the sealing means is in use between mating surfaces.
with ?uid under pressure the force exerted tends to force
When sealing means of the above-described type are
both projections into tighter sealing engagement. Also
such ?uid under pressure becomes entrapped and prevents
used between mated surfaces, the resilient deformable
packing member is forced completely into the groove.
mechanical shifting of the deformed projecting portions
The resilient packing member therefore exerts a con
under surge or ?uctuations in the outside pressures. Wear
tinual force against a mating surface and thereby forms
ing means of this type is shown and described in US.
and abrasion of the packing member from such shifting
is therefore avoided.
It is to be noted, that in forming the seal of the present
an effective pressure seal.
One desirable form of seal
Patent No. 2,717,793, issued September 13, 1955, to
invention, the mold for forming the deformable member
Joseph F. Nenzell.
In such seals the packing member is resiliently de
extends into the groove in a single central section which
is well removed from the edges of the groove in the rigid
formed into void spaces formed at the sides of a central
retaining member. As a result, the danger of the mold
contacting the rigid retaining member is substantially re
duced. Further, in accordance with the present inven
projection. One of these voids is, of course, on the pres
sure side of the seal and as ?uid under pressure attempts
to pass the central area it forces the central projection
tion, the sprue openings into a cavity formed between a
mold and the rigid retaining member or body may be posi
manner of the well known 0 ring. If this pressure is
tioned in a wide part of the mold which forms the single
surging or cycling from a high .to a low value there is 40 channel in the packing member. -As a result, the ?ash
constant working or shifting of the sealing portion of the
formed at the sprue opening is located in a relatively un
packing member in accordance with the pressure. Over
important surface and additionally the sprue openings
an extended period of time this movement of the packing
may be made of a larger, more desirable size.
member causes abrasion and wear of the sealing contact
With the foregoing in mind, it is a major object of the
present invention to provide an improved sealing means
surface and leakage may occur. Also loss of resilience
due to material fatigue may take place.
having a resilient deformable packing member mounted
‘within a relatively rigid retaining body and establishing
As mentioned, seals of the type described above nor
mally utilize a single central protrusion or projection
two areas of sealing contact.
similar to an 0 ring, which emanates or projects from a
It is also an object of the invention to provide a seal
groove in the rigid retaining body. This projection may
of the character described in which the cross-sectional
shape of the packing member results in a single central
then be deformed into channels, which are provided in
the member on both sides of the projection. The mold
void space and thereby provides optimum sealing qualities.
used to form the resilient deformable packing member
An additional object of the invention is to provide a
must therefore extend into the groove in the rigid retain
seal in which opposed packing members are formed in
into sealing engagement with the opposed surface in the
a single rigid retaining body in such a manner as to re
ing body in two side locations adjacent the groove walls,
to form the channels in the resilient deformable packing
sult in an improved seal between mating surfaces.
member. Because of the con?guration of seals of this
These and other objects and advantages of the inven
type, the mold must pass quite close to the walls of the
tion will become apparent from the following detailed
groove in the rigid retaining body, and in the event of 60 description of preferred and modi?ed embodiments of
slight misalignment, the mold may actually be urged
the invention and from an inspection of the accompany
against the rigid retaining body. In the event of such mis
ing drawings in which:
alignment causing the mold to contact the rigid retaining
FIGURE 1 is an enlarged partial cross-sectional view
body, the mold will usually be permanently damaged
taken through a preferred form of ?uid seal constructed
resulting in a considerable loss.
‘
65 in accordance with the present invention;
In forming a seal of the above-described type wherein
FIGURE 2 is a partial cross-sectional view taken
a single projection is formed in the resilient deform
through a typical joint embodying the seal of the present
able member to project from a groove, the resilient de
invention;
formable member may be formed by injecting material
FIGURE 3 is an enlarged cross-sectional view of a
into the groove while the material is in a plastic transi 70 portion of the typical joint shown in FIGURE 2.
tional state. The material, in a plastic state, will nor
FIGURE 4 is a cross-sectional view through a mold
mally be injected into a cavity between the mold and the
and the retainer body showing the method and apparatus
rigid retaining body through sprue openings. If the sprue
for forming the sealing means of the present invention;
3,061,321
3
FIGURE 5 is a cross-sectional view taken through a
modi?ed sealing means constructed in accordance with
the present invention; and
FIGURE 6 is a partial plan view of a seal means con
structed in accordance with the present invention showing
a portion of the packing member broken away.
Referring now to the drawing, and particularly to
FIGURES l, 2 and 3 thereof, the numeral 10 designates
generally a retaining body, formed of rigid material such
4
channel 30 and the fact that it is the only void space
within the groove 14 becomes very important. There are
always two outside ?uid pressures acting across the seal
and these are represented in FIGURE 3 as P1 and P2.
Assume that P1 is the greater of these two pressures,
and that, as in the case in most pneumatic and hydraulic
equipment, P1 is a ?uid pressure which may surge or
?uctuate between large limits.
When the seal is initially deformed to the shape shown
as metal, to contain the resilient deformable packing 10 in FIGURE 3 the channel 30 is a void space ?lled only
member 12. The packing member 12 may be formed
of various materials which are resiliently deformable.
Synthetic rubber having a high compression resilience is
one material which is satisfactory for use as the resilient
with the air entrapped therein under a relatively low
pressure.
However, when the equipment is operating
and a high value of the ?uid pressure P1 is reached, this
?uid forces its way towards the groove 14 and trys to
15 pass by the deformed projection 16. Some leakage of
deformable packing member 12.
this ?uid over the projection may occur. As this hap
The packing member 12 is molded in the retaining
body 10 so that the surfaces of a continuous groove 14
in the retaining body 10 are in complete contact with the
resilient packing member.
By reason of the packing
pens, the channel 38 becomes ?lled with ?uid under the
high pressure value P1 and this pressure now acts in a
direction to force both the deformed projections 16 and
18 into tighter sealing engagement with the opposing
member 10 being in full contact with the surfaces of the
surface 28. Considering now the deformed projection 18
groove 14, variations in the size of the groove 14 result
it will be seen that both the pressure P1 and the resilience
ing from manufacturing inaccuracies will not affect the
of the packing material are acting to tighten the sealing
seal, as will be explained hereinafter.
engagement against surface 28. If the value of P1 in
The packing member 12 is formed in such a manner
as to have projections 16 and 18 which extend above the 25 creases, the sealing engagement of deformed projection
18 becomeseven greater, and any ?uid leakage across
surface 20 of the retaining body 10 and are preferably
the groove is effectively resisted.
of rounded semicircular cross section. Between the pro
When the value of P1 decreases the ?uid under pres
jections 16 and 18 is a rounded concave channel 22, into
sure in channel 30 remains under the higher initial value
which the projections 16 and 18 may be deformed. The
total volume of the projections 16 and 18 which rise 30 since it cannot escape back over the deformed projection
16. This is an important factor in stabilizing the seal
above the surface 20 is slightly less than the volume of
and preventing mechanical shifting of the packing mem
the channel 22 which lies beneath the surface 20. It
her under surging or cyclical pressure conditions. It
should also be noted that the material of the packing
has been found 'by tests that in certain high pressure
member 12 outside of the projections 16 and 18 com
equipment, wherein O-ring seals in grooves are used,
pletely ?lls the groove 14 ?ush with the surface 20 so
there is sealing failure due to actual abrasion and wear
that there is no void space at or near the side edges of
of the seal caused by changes in shape and position of the
the groove.
seal under changing pressure conditions. This problem
Referring speci?cally now to FIGURE 2, there is shown
the retaining body 10 incorporating the packing member 40 is clearly overcome by the design of the subject device.
To form the described embodiment of the sealing
12 drawn into contact by a bolt 24 with a faced part 26
means,
molding apparatus as shown in simpli?ed form
having a surface 28. It is to be noted, that the surface
in FIGURE 4 may be used. The molding apparatus
28 mates with the surface 20 of the retaining body 10.
includes a mold 32 having a forming face 34 shaped in
FIGURE 3 shows an enlarged section of FIGURE 4,
such a manner as to form the sealing surface of the pack
wherein the resilient deformable packing member 12 may
ing member 12. The forming face 34 is supported over
be seen to be deformed in such a manner as to lie com
the groove .14 by a supporting face 35, to thereby form
pletely within the groove 14. Due to the volumetric
a cavity into which the material forming the packing
relationship between the packing member 12 and the
member may be forced. The molding operation takes
groove 14, a small void channel 30 exists in the packing
place while the material to form the packing member is
member 12 when the part 26 is drawn against the retain
in a plastic transitional state and is injected by pressure
ing body 10. Void channel represents, of course, the
into the cavity.
volume of channel 22 which is not ?lled by projections
The mold face 34 is shaped to provide a central sec
16 and 18 and is located at the very center of groove 14.
tion and side sections which are complemental to the
This void channel 30 is provided to assure that the volume
shape of the ?nished packing member as previously de
of the packing member 12 does not exceed the volume of
scribed. A central projection 36 extends downwardly
the groove 14. As previously indicted, if the volume of
beyond the plane of supporting ‘face 35 and is of rounded
the packing member 12 exceeds the volume of the groove
generally semi~circular cross section. This projection 36
14, extrusion of the material of the packing member out
forms the central channel 22 in the packing member.
side of the groove and between the surfaces 20 and 28
On each side of the central projection 36 are concave
will occur. Such condition will permit leakage, destroy 60 rounded channels 37 which are recessed above the plane
the reusability of the packing member, and weaken the
of supporting face 35 and form the member projections
strength of the structure.
16 and ‘18. The volumetric relationship of channels 37
To prevent such extrusion it is not necessary that the
to projection 36 in relation to the supporting plane is
volume of channel 22 actually exceed the volume of pro
such that the volume of the latter is slightly ‘greater than
jections 16 and 18. However, under manufacturing con
the total volume of the two channels for the reasons pre
ditions some tolerance is necessary, and the void pocket
viously mentioned. It should be noted that this relation
30 is therefore highly desirable. When the projections
ship exists independent of variations in the depth, width,
16 and 18 are deformed down into channel 22 it will be
or other irregularities in the shape of groove 14 which
seen that all of the internal ?ow is away from the sides
may occur in manufacturing.
of the groove 14 where pinching of the material of the 70
The overall width of the forming face 34 between the
outer edges of the two channels 37 is somewhat less than
packing member could occur. After being deformed,
the minimum width of groove 14 so that the outer por
it will also be seen that the projections 16 and 18 exert
tions of member 12 are formed ?ush with the surface
a strong upward pressure creating two areas of sealing
of body 10 as previously described. As will be under
contact to resist ?uid ?ow across the groove.
Under high pressure conditions, the positioning of void
stood, in the molding operation the body 10 is held rigidly
3,061,321
6
in place relative to mold 32 and the latter is seated tight
ly down on the surface 20. With proper registration,
projection 36 is just centered in groove 14 as shown in
the foregoing except as de?ned in the appended claims.
I claim:
FIGURE 4. In manufacturing, misregistration or a de
fective groove 14 may occur, and if the projection 36
were to be forced into engagement with the rigid sur
face 20, destruction or severe damage to the expensive
mold 34 would occur. In this connection the design of
the seal is of great importance since it will be seen that
opposed part: a retaining body including a ?at part-en
gaging surface, said surface being provided with a con
1. In a sealed joint in combination with a ?at faced
tinuous groove; and a resilient deformable packing mem
ber molded in said groove with its side portions ?ush with
the outer edges of said groove and prior to assembly
in said sealed joint rising therefrom to form a pair of
a relatively great amount of misregistration of the mold 10 symmetrical projections extending beyond the surface of
said body for engagement with said opposed part, said
of striking the projection 36 on the surface 20.
member including a single central void channel therein
In order to inject the plastic packing material into the
between said projections and lying within said groove be
cavity formed by groove 14 and forming face 34 sprue
low said part-engaging surface, and having a total vol
openings 38 are provided. These sprue openings are 15 ume below the plane of the part-engaging surface prior to
preferably extended downwardly through projection 36
assembly greater than the volume of said projections
and may be relatively large in accordance with the widths
above the plane of the part-engaging surface prior to as
of the projection. This again provides a twofold advan
sembly and forming a fluid trap space between the de
tage in manufacturing. First, the ?ash formed at the
formed projections when assembled in said sealed joint.
sprue openings is away from the working portions 16 and 20
2. In a sealed joint in combination with a pair of op— '
18 of the member where actual sealing contact is made.
posed ?at faced parts: a retaining body having opposed
Less accurate and inexpensive ?ash trimming operations
?at part-engaging surfaces, said surfaces being provided
may therefore be used. Also, the use of relatively large
with continuous grooves; a resilient deformable packing
sprue openings permits lower injection pressures and less
member molded in each of said grooves in contact with
expensive molding equipment.
25 substantially all the side and bottom surfaces within
A modi?ed ‘form of the seal which may be designated
said groove, and prior to assembly in said sealed joint
as a two-sided seal is shown in FIGURES 5 and 6. This
rising therefrom to form a pair of projections extending
form of the invention is particularly useful wherein two
beyond the surface of said body for engagement with one
abutting members must be sealed such as in the case of
of said opposed parts, said member including a single
a joint between ?anged pipe sections. In this modi?ed 30 central void channel therein between said projections
form of the seal the packing member is formed into a
and lying within said groove, and having a total vol
separate rigid body which is disposed between the two
ume below the plane of the adjacent part-engaging sur
abutting members forming the joint.
face prior to assembly greater than the volume of said
As shown in FIGURE 5, two resilient deformable
projections above the plane of the same part-engaging
packing members 40 and 42 are placed in grooves 44 35 surface prior to assembly and forming a fluid trap space
and 46 in a plate 48. The plate 48 constitutes the re
between the deformed projections When assembled in said
taining body for both packing members and may be of
sealed joint.
any desired con?guration. The shape of packing mem
3. In a sealed joint in combination with a ?at faced op
bers 40 and 42 are the same in all respects as the shape of
posed part: .a retaining body including a ?at part-en
the packing member 12 as has previously been described. 40 gaging surface, said surface being provided with a con_
and groove 14 can occur before there is any possibility
In addition, openings 50 are formed between the grooves
44 and 42 so that the two packing members 40 and 42
are interconnected back to back. This is accomplished
tinuous groove; and a resilient deformable packing mem
ber molded in said groove in contact with substantially
all the side and bottom surfaces within said groove, and
prior to assembly rising therefrom to form a plurality of
through the molding operation by ?owing the material of
the packing members through the openings 50 to form 45 projections extending beyond the surface of said body
integrally with each of the packing members short stub
for engagement with said part, said member including
like connectors of the parent material. These connec
a continuous void channel therein between said projec
tors serve to hold the packing members 40 and 42 in
tions and lying within said groove, and having a total
place and prevent movement of either relative to the
volume below the plane of the part-engaging surface prior
plate 48.
50 to assembly greater than the volume of said projections
The embodiment of the invention shown in FIGURES
above the plane of the part-engaging surface prior to
5 and 6 is formed by molding apparatus in which a pair
assembly and forming a ?uid trap space between the de
of molds similar to the mold 32 are utilized on either
formed projections when assembled in said sealed joint.
side of the plate 48. Since the material injected into
the cavity formed by the molds and the grooves may ?ow 55
References Cited in the ?le of this patent
through the openings 50 from one side to ‘the other of
UNITED STATES PATENTS
plate 48, it is only necessary that one set of sprue open
ings 38 be provided, and thus ?ash. need be trimmed
from only one side of the ?nished product.
While I have thus shown and described in some detail 60
different ‘forms of the seal and the apparatus and the
methods for forming the same, it will be understood
that changes of design and construction in both the seals
and the manufacture thereof may be made by those skilled
in the art. Therefore, I do not wish to be limited to 65
1,976,797
2,055,103
2,505,540
I2,513,178
Naylor ______________ __ Oct. 16,
Hewitt ______________ __ Sept. 22,
Goldhard ____________ __ Apr. 25,
Jackson ____________ __ June 27,
1934
1936
1950
1950
2,629,132
Wilcox et a1. ________ __ Feb. ‘24, 1953. ~
2,717,793
2,723,142
2,764,311
2,842,388
.Nenzell ____________ __ Sept. 13,
Stebbins ____________ __ Nov. 8,
Blackman __________ __ Sept. 25,
Holdeman ____________ __ July 8,
1955
1955
1956
1958
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