U.S. patent application number 10/698339 was filed with the patent office on 2004-08-05 for packing material and gland packing used the material.
Invention is credited to Sakura, Toshiharu, Tsukamoto, Hiroaki, Tsukamoto, Katsuro.
Application Number | 20040151905 10/698339 |
Document ID | / |
Family ID | 32767592 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040151905 |
Kind Code |
A1 |
Tsukamoto, Katsuro ; et
al. |
August 5, 2004 |
Packing material and gland packing used the material
Abstract
The purpose of the present invention is to provide a packing
material having enough durability even if it is used under high
temperature and high pressure, and also the purpose of the present
invention is to provide the packing material that only one type of
the gland packing is enough to be used in a stuffing box. The
present invention relates to a packing material comprising an
expansive graphite tape is mounted on one or both sides of plain
state carbon fiber to make a first laminated tape, and it is
twisted to be a filament, and to make a second laminated tape, an
expansive graphite sheet is mounted on one or both sides of a
reinforcing material comprising plural reinforcing fibers or
reinforcing wires aligned in approximately parallel each other or a
reinforcing material which a woven is cut into a strip, and said
second laminating tape is wound around said filament. Further, it
is better that to make a third laminated tape, the expansive
graphite tape is mounted on one or both sides of the plain state
carbon fiber, and instead of said second laminated tape, the third
laminated tape is wound around said filament.
Inventors: |
Tsukamoto, Katsuro;
(Takarazuka City, JP) ; Sakura, Toshiharu; (Osaka
City, JP) ; Tsukamoto, Hiroaki; (Takarazuka City,
JP) |
Correspondence
Address: |
Henneman & Saunders
714 W. Michigan Ave.
Three Rivers
MI
49093
US
|
Family ID: |
32767592 |
Appl. No.: |
10/698339 |
Filed: |
October 31, 2003 |
Current U.S.
Class: |
428/373 |
Current CPC
Class: |
Y10T 428/2929 20150115;
D02G 3/06 20130101; F16J 15/22 20130101 |
Class at
Publication: |
428/373 |
International
Class: |
D02G 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2003 |
JP |
2003-024483 |
Claims
What is claimed is:
1. Packing material comprising: an expansive graphite tape is
mounted on one or both sides of plain state carbon fiber to make a
first laminated tape, and it is twisted to be a filament, and to
make a second laminated tape, an expansive graphite sheet is
mounted on one or both sides of a reinforcing material comprising
plural reinforcing fibers or reinforcing wires aligned in
approximately parallel each other or a reinforcing material which a
woven is cut into a strip, and said second laminating tape is wound
around said filament.
2. The packing material described in claim 1, wherein to make a
third laminated tape, the expansive graphite tape is mounted on one
or both sides of the plain state carbon fiber, and instead of said
second laminated tape, the third laminated tape is wound around
said filament.
3. The packing material described in claim 1, wherein the filament
is made by twisting the first laminated tape so that a reinforcing
core is covered with the first laminated tape.
4. The packing material described in claim 2, wherein the filament
is made by twisting the first laminated tape so that a reinforcing
core is covered with the first laminated tape.
5. A gland packing made into a predetermined shape by pressing a
braided material comprising the braided packing material described
in claim 1.
6. A gland packing made into a predetermined shape by pressing a
braided material comprising the braided packing material described
in claim 2.
7. A gland packing made into a predetermined shape by pressing a
braided material comprising the braided packing material described
in claim 3.
8. A gland packing made into a predetermined shape by pressing a
braided material comprising the braided packing material described
in claim 4.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a packing material and
gland packing used the material, more detail, the present invention
relates to a gland packing and its material, which has enough
durability even if it is used not only under normal temperature and
low pressure but also under high temperature and high pressure. In
each case, the gland packing can keep high lubricating property
over the long term, and the gland packing can be used for both a
valve and a pump. Further, by using the gland packing, other type
of gland packing does not need to be used in a stuffing box.
[0003] In the specification, allowable tensile force means the
product of a tensile strength (kgf/cm.sup.2) of the materials, and
the cross-sectional area (cm.sup.2) of the materials in a case of
the materials resulting in a fracture.
[0004] 2. Description of the Related Art
[0005] As a gland packing which seals a shaft of a fluid machinery
such as a pump or valve, there is a gland packing which is made
from asbestos, carbonized fibers, carbon fibers, and aramid resin
fibers.
[0006] Further, there are gland packings which are comprised
above-mentioned materials which are involved PTFE (For example,
Tokukaihei 6-101764). These gland packings are packed in a space
which is made in-between a shaft and an apparatus casing, i.e., the
inside of the stuffing box, in order to prevent fluid from leaking
out from in-between the shaft and the apparatus casing.
[0007] Required performance of the gland packing is slightly
different between the pump and valve. In sealing of a shaft of the
pump, at first, high lubricating ability is required so as not to
prevent high velocity revolution of the shaft, and then high
sealing ability and pressure resistance ability are required. Some
leaking of fluid is allowed, because the leaking let frictional
heat out.
[0008] On the other hand, in a sealing of a shaft of the valve, at
first, high sealing ability and pressure resistance ability are
required so as not to leak high pressure fluid, and then, high
lubricating ability is required. Since the shaft of the valve
rotates around the shaft and linearly goes and return, the shaft of
the valve has been protruded in a gap between the shaft and a
roller bearing by changing the shape of a part of a packing, and
running torque of the shaft rapidly accelerates by the protrusion.
Therefore, pressure resistance ability is very important in the
packing for the valve.
[0009] The conventional gland packing cannot harmonize all of
lubricating ability (low torque ability), pressure resistance
ability and heat resistance at a high level, and the gland packing
cannot be used long term under very high pressure and high
temperature (for example, as a valve for a generating power
plant).
BRIEF SUMMARY OF THE INVENTION
[0010] The present invention is invented in consideration of these
cases, its purpose is to provide a gland packing and its material
that have enough durability even if it is used not only under
normal temperature and low pressure but also under high temperature
and high pressure, and in each case, the gland packing and its
material can keep high lubricating property over the long term, and
it can be used for both a valve and a pump. Further, the purpose of
the present invention is to provide the gland packing that other
type of gland packing does not need to be used in a stuffing
box.
[0011] The present invention described in claim 1 is a packing
material comprising an expansive graphite tape is mounted on one or
both sides of plain state carbon fiber to make a first laminated
tape, and it is twisted to be a filament, and to make a second
laminated tape, an expansive graphite sheet is mounted on one or
both sides of a reinforcing material comprising plural reinforcing
fibers or reinforcing wires aligned in approximately parallel each
other or a reinforcing material which a woven is cut into a strip,
and said second laminated tape is wound around said filament.
[0012] The present invention described in claim 2 is the packing
material described in claim 1, wherein to make a third laminated
tape the expansive graphite tape is mounted on one or both sides of
the plain state carbon fiber, and instead of said second laminated
tape, the third laminated tape is wound around said filament.
[0013] The present invention described in claim 3 is the packing
material described in claim 1, wherein the filament is made by
twisting the first laminated tape so that a reinforcing core is
covered with the first laminated tape.
[0014] The present invention described in claim 4 is the packing
material described in claim 2, wherein the filament is made by
twisting the first laminated tape so that a reinforcing core is
covered with the first laminated tape.
[0015] The present invention described in claim 5 is a gland
packing made into a predetermined shape by pressing a braided
material comprising the braided packing material described in claim
1.
[0016] The present invention described in claim 6 is a gland
packing made into a predetermined shape by pressing a braided
material comprising the braided packing material described in claim
2.
[0017] The present invention described in claim 7 is a gland
packing made into a predetermined shape by pressing a braided
material comprising the braided packing material described in claim
3.
[0018] The present invention described in claim 8 is a gland
packing made into a predetermined shape by pressing a braided
material comprising the braided packing material described in claim
4.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a view showing a filament in a first embodiment of
the present invention.
[0020] FIG. 2 is a view showing a twisting of the filament showing
in FIG. 1, and a view showing a first laminated tape which is
twisted.
[0021] FIG. 3 is a cross sectional view showing the first laminated
tape and mounted materials used in order to make the first
laminated tape of present invention.
[0022] FIG. 4 is a view showing other example of the filament in a
first embodiment.
[0023] FIG. 5 is a view showing a twisting of the filament shown in
FIG. 4, and a view showing the first laminated tape so that it is
twisted to cover a reinforcement wire rod which is mounted at the
central of the filament.
[0024] FIG. 6 is a view showing a making of a packing material
which relates to the first embodiment, and a view showing a winding
of a second laminated tape around the filament.
[0025] FIG. 7 is a cross sectional view cut in the width direction
showing the second laminated tape of the present invention, and (a)
is a view showing a mounting of an expansive graphite tape on one
side of reinforcing material, and (b) is a view showing a mounting
of the expansive graphite tape on both sides of the reinforcing
material.
[0026] FIG. 8 is a view showing a braiding of the packing material
which relates to the present invention.
[0027] FIG. 9 is a view showing a braiding of the packing material
which relates to the present invention.
[0028] FIG. 10 is a view showing a braiding of the packing material
which relates to the present invention.
[0029] FIG. 11 is a view showing a braiding of the packing material
which relates to the present invention.
[0030] FIG. 12 is a view showing a gland packing which relates to
the present invention.
[0031] FIG. 13 is a view showing a packing material which relates
to the second embodiment, and (a) is a perspective view showing a
partially dissolving of the packing material, and (b) is a A-A line
sectional view of (a).
[0032] FIG. 14 is a graph showing a number of sliding of a shaft in
a performance test of the packing.
[0033] FIG. 15 is a graph showing a result of a leakage test.
[0034] FIG. 16 is a graph showing a result of a sliding resistance
test (in change of direction in back-and-forth motion).
[0035] FIG. 17 is a view showing a result of a sliding resistance
test (in change of direction in one way).
[0036] FIG. 18 is a view showing a result of a bearing test.
[0037] FIG. 19 is a schematic sectional view of a packing material
which relates to a comparative example 1.
[0038] FIG. 20 is a view showing a schematic sectional view of a
packing material which relates to a comparative example 2.
DESCRIPTION OF PREFERED EMBODIMENTS OF THE INVENTION
[0039] Hereinafter, the present invention is explained with
referring to the drawings.
[0040] At first, a packing material which relates to the first
embodiment of the present invention is explained.
[0041] FIG. 1 is a view showing a filament in a first embodiment of
the present invention. FIG. 2 is a view showing a twisting of the
filament showing in FIG. 1, and a view showing a first laminated
tape which is twisted. FIG. 3 is a cross sectional view showing the
first laminated tape and mounted materials used in order to make
the first laminated tape of the present invention.
[0042] The gland packing of the present invention (1) (refer to
FIG. 12) is braided a filamentous packing material (2) (refer to
FIG. 6), and the braided body (3) (refer to FIG. 8 to 11) is
pressed to a predetermined shape.
[0043] The packing material (2) which relates to the first
embodiment (refer to FIG. 6) is made from at first, a filament (20)
which is made by twisting a first laminated tape (4) which is made
by mounting an expansive graphite tape (6) on one side or both
sides of a plain state carbon fiber (7) (refer to FIGS. 2 and 3). A
second laminated tape (12) (refer to FIGS. 6 and 7) is made by
mounting an expansive graphite tape (60) on one side (refer to FIG.
7 (a)) or both sides (refer to FIG. 7 (b)) of a reinforcing
material which is made by cutting a fabric into a strip or the
reinforcing material (11) which is made by placing plural
reinforcing fibers or plural reinforcing wire) (10) (refer to FIG.
7) approximately parallel, and the second laminated tape (12) is
winded around said filament (20).
[0044] FIG. 2 shows a first laminated tape (4) which is twisted.
The first laminated tape (4) is made by cutting a laminated sheet
(5) shown in FIG. 3 like strip. The laminated sheet (5) is made by
mounting plain state carbon fiber (7) on an expansive graphite
sheet (61) with an adhesive layer (8). The adhesive layer (8) has
two functions as adhesive and function as reinforcing material.
[0045] The type of the adhesive layer (8) is not particularly
limited and can be made from organic adhesives, inorganic adhesives
and mixture of organic and inorganic adhesives and the like. The
adhesive layer (8) can be taken form of liquid, emulsion, film,
non-woven fabric and the like. Further, a mounting method of
adhesives is not limited, and it can be selected from application,
thermocompression bonding, spray and such.
[0046] It is desirable to use water soluble thermal plasticity
adhesives, and it is more desirable to use non-polluting polyvinyl
alcohol for the adhesive layer (8). Polyvinyl alcohol can be used
by applying to a surface of the expansive graphite sheet (6) or
carbon fiber by keeping the polyvinyl alcohol liquid or by
blasting. When the adhesive layer (8) is mounted by blasting, for
example, it can be mounted as sort of non-woven fabric.
[0047] When polyvinylalcohol (hereinafter referred to as PVA) is
used to the non-woven fabric, the adhesive layer (8) is mounted
that PVA resin fibers extend to irregular direction, and a sheet is
made by fixing the PVA resin mutually. The adhesive layer (8) has
great tensile strength against tensile force in any directions, and
especially in a condition where the adhesive layer (8) is made to
be a strip, it shows great tensile strength against tensile force
from the axial direction.
[0048] In gluing the expansive graphite sheet (61) and the plain
state carbon fiber (7), these can be strongly mounted by
intervening the PVA adhesive layer (8) between the expansive
graphite sheet (61) and the plain state carbon fiber (7) and by
pressuring from both sides or by pressuring with heating.
[0049] As the expansive graphite sheet (61), after making an
interlayer compound by reacting graphite powder such as natural
graphite and kish graphite with concentrated sulfuric acid,
concentrated nitric acid and the like, the residue of the compound
is gained by a water bathing, and it is expanded by a quick heating
so that to gain expansive flexible graphite, and the expansive
flexible graphite is molded with compression with a rolling
material so that to make a sheet shape.
[0050] The density of the expansive graphite sheet (61) is not
limited particularly, but it is preferred 0.80.about.2.2
g/cm.sup.3. When the density is in this range, unevneness in
crystal level is made on the surface of the expansive graphite
sheet (61), and it can cause an anchor effect to the mounted
material thereon. On the other hand, when the density is less than
0.80 g/cm.sup.3, texture of organization becomes too rough, leading
a lowering of sealing ability of packing being made. Further, when
the density is more than 2.2 g/cm.sup.3, there is a possibility
that the texture of organization becomes too fine to cause the
anchor effect, and not to satisfactorily laminate with the plain
state carbon fiber (7).
[0051] Furthermore, the thickness of the expansive graphite sheet
(61) is not limited particularly, but it is preferred
0.10.about.1.5 mm, and more preferably it is 0.12.about.0.2 mm.
When the thickness is less than 0.10 mm, outstanding heat
resistance, corrosion resistance, and abrasion resistance of the
expansive graphite cannot be manifested. Further, such a thin
expansive graphite sheet is uneconomical because of difficultness
of manufacture. On the contrary, when the thickness of the
expansive graphite sheet is more than 1.5 mm, brittleness of
expansive graphite appears.
[0052] The plain state carbon fiber (7) functions to reinforce the
expansive graphite sheet (61), to cover for elasticity and to roll
a solid lubricant material. The plain state carbon fiber (7) is
mounted on a surface of the expansive graphite sheet (61) with the
adhesive layer (8). The plain state carbon fiber (7) is mounted
with using the mounting method as mentioned-above. In case of a
heat anastomosis film is used as adhesive, for example, a PVA plain
state fabric, PVA film, polyethylene film, olefin film and urethane
film can be used.
[0053] The plain state carbon fiber (7) is a strip fabric
aggregation which properly raxes a strengthen fabric such as a
carbon fiber from the original width to necessary width.
[0054] The plain state carbon fiber (7) surpasses in physical
strength, and hardly changes its property such as physical strength
between -200.degree. C..about.+600.degree. C., so it also surpasses
properties of under low temperature and high temperature.
Therefore, the plain state carbon fiber (7) can be surely
reinforced the expansive graphite sheet (61) under circumstance of
severity temperature as well as ordinary temperature. Further,
since the plain state carbon fiber (7) has outstanding lubricating
and sealing ability, it can obtain the packing (1) having
outstanding lubricating and sealing ability by constructing
braiding thread as the plain state carbon fiber (7) is positioned
outside the packing (1). Moreover, since plain state carbon fiber
(7) surpasses in corrosion resistance and abrasion resistance, it
can be used long-term even under harsh environment, such as a
chemical plant.
[0055] It is desirable that the thickness of the plain state carbon
fiber (7) is 0.01.about.0.5 mm, and it is more desirable
0.15.about.0.2 mm or 0.01.about.0.02 mm. In case of the thickness
is less than 0.01 mm, it cannot obtain enough lubricating and
sealing ability, on the other hand, in case of the thickness is
more than 0.5 mm, the plain state carbon fiber (7) cannot obtain
enough flexibility.
[0056] The manufacturing method of the plain state carbon fiber (7)
is not limited particularly, a fiber (carbon fiber) called
multifilament can be thin and wide plain state by using for
example, supersonic or fluid flow. Thickness of the plain state
carbon fiber (7) is preferably plain-woven several dozen .mu.m or
less than, for example, width is more than 25 mm and thickness is
less than 20 .mu.m.
[0057] In a manufacturing process of the first laminated tape (4),
there is a process of cutting the laminated sheet (5) like a strip,
each fiber of the plain state strip carbon fiber is equally
arranged with high density, and big frictional force works in each
fiber.
[0058] Therefore, each fiber is interconnected tightly along the
axial direction and right angle direction against the axial, the
first laminated tape (4) becomes a strip which has big tensile
strength. Usually, a plain state carbon fiber is made by gathering
various length carbon fibers to constant direction and closing up.
That is, various length carbon fibers are mounted in the axial
direction and right angle direction against the axial. In these
aggregation of fibers, as mentioned-above, each fiber is
interconnected with big tensile force each other. Therefore, the
aggregation can be a durable strip, even if it is cut on the
cross.
[0059] A width of the first laminated tape (4) is 5.about.30 mm,
and preferably it is 5.about.25 mm. When the width is more than 30
mm, flexibility of the first laminated tape (4) comes down, and it
becomes difficult to fabricate to a filament. Conversely, when the
width is less than 5 mm, tensile strength of the first laminated
tape (4) comes down extremely, and the first laminated tape (4) may
fracture when it is processed into the filament (20). In case of
the width is 5.about.30 mm, the first laminated tape (4) is in no
risk of fracture when it is twisted, because it has enough tensile
strength.
[0060] The first laminated tape (4) can be made relatively thin,
because it is reinforced by the plain state carbon fiber (7)
fibersand adhesive layer (8). Therefore, not only the first
laminated tape (4) which has 5.about.10 mm width but also the first
laminated tape (4) which has more than 10 mm width can have enough
flexibility. When the filament (20) is made by using the first
laminated tape (4) of 5.about.10 mm width, a cord (3) used a number
of cord such as twenty four or thirty two can be made. Further, the
cord (3) used a number of cord can be made from the filament (20)
which has various thickness. By this, a packing (1) which has high
sealing ability can be obtained, because a cord (3) which is dense
of its inside.
[0061] The first laminated tape (4) is twisted to be the filament
(20). When the first laminated tape (4) has the expansive graphite
sheet (6) at only one side of the plain state carbon fiber (7), in
a twisting of the first laminated tape (4), the plain state carbon
fiber (7) is mounted outside or the expansive graphite sheet (6) is
mounted outside. Each case is available, but in case of the plain
state carbon fiber (7) is twisted so that it is mounted inside,
when the packing is made, a part of the plain state carbon fiber
(7) is not exposed on exterior surface of the packing.
[0062] A twisting method of the first laminated tape (4) of the
present invention is not limited particularly, but a method which
twists tightly the first laminated tape (4) which is folded at
center of width direction or a method which twists the first
laminated tape (4) without folding (refer to FIG. 2) can be
employed.
[0063] The preferable twisting numbers are about 55.about.70 per 1
m. With this numbers of twisting, the inventor has found that the
strength of the filament (20) becomes extremely high.
[0064] The plain state carbon fiber (7) made by the plain state
carbon fiber such as carbon fiber multifilament surpasses
lubricating ability, abrasion resistance, corrosion resistance,
physical strength and sealing ability. Therefore, by using the
plain state carbon fiber (7) as a packing material, it can obtain a
packing (1) which surpasses lubricating ability, abrasion
resistance, corrosion resistance, physical strength and sealing
ability.
[0065] Since the filament (20) surpasses in flexibility, a
complicated braiding can easily be carried out, and even when
carrying out a complicated processing, a laminated sheet (4) does
not fracture. Also, there is no risk of fracturing during a
braiding, because the first laminated tape (4) which makes the
filament (20) has enough allowable tensile force.
[0066] Furthermore, the filament (20), as shown in FIG. 4 and FIG.
5, can be comprised from a structure with a reinforcing core (9).
To be more precise, as shown in FIG. 5, the filament (20) can
comprise a structure that the first laminated tape (4) is twisted
around the reinforcing core (9) so that the first laminated tape
(4) covers the reinforcing core (9). In such case, allowable
tensile force of the filament (20) can increase more than it is
made from the first laminated tape (4) only. The material of the
reinforcing core (9) is not particularly limited, but any materials
can suitably be used if it has enough strength as a packing
material, for example, metal such as Monel metal, inconel,
ferrochrome, stainless, copper and aluminum, glass fiber, ceramic
fiber, synthetic resin such as aramid resin,
polytetrafluoroethylene resin (PTFE), nylon resin, acrylate resin
and phenol resin, material that soaks lubricating oil to these
synthetic resin, carbide of these synthetic resin and asbestos.
[0067] It is preferable for the reinforcing core (9) to have its
diameter 0.15.about.0.3 mm, and more preferable the diameter is
0.25 mm. If the diameter is such length, the first laminated tape
(4) can easily be twisted.
[0068] Additionally, the reinforcing core (9) can be used singly,
but plural reinforcing core (9) can also be used as described
below. If a single reinforcing core (9) is used, for example, it
may be used without braiding, or it may be used as a cord which was
braided. Further, if plural reinforcing cores (9) are used, these
may be used by braiding together, or these may be used as a cord
which has been braided.
[0069] The sectional form of each wire which makes the reinforcing
core (9) is not particularly limited, for example, it can take many
configurations such as orbicular section, rectangle section and
elliptical section and such.
[0070] The second laminated tape (12) is made by mounting the
expansive graphite tape (60) on one side or both sides of a
reinforcing material (11) comprising plural reinforcing fibers or
plural reinforcing wires (10), or a strip reinforcing material made
by cutting woven.
[0071] The second laminated tape (12) performs as a solid lubricant
and as a reinforcing material, and also prevents the plain state
fiber from sticking out of the surface of the packing material (2)
as like mustache.
[0072] When the plain state fiber sticks out of the surface of the
packing material (2), a gland packing by a pressuring the packing
material (2) will also have the fibers sticking as like mustache on
its surface. The fibers sticking out could facilitate early
worn-out of a shaft such as a rotating shaft, which could result in
leakage of fluid.
[0073] The reinforcing material (11) may comprise plural
reinforcing fibers, plural reinforcing wires (10), or by cutting a
woven into a strip.
[0074] Although the material of the reinforcing fibers, the
reinforcing wires (10) and the woven is not particularly limited,
for example, the reinforcing wires could comprise Monel metal,
inconel, stainless steel, copper or aluminium, and the reinforcing
fiber could comprise glass fibers, ceramic fibers, synthetic resin
comprising aramid resin, polytetrafluoethylene resin (PTFE), nylon
resin, acryl resin, phenolic resin and etc, carboniser of fibers
comprising these synthetic resin (carbon fiber) or asbestos. Cotton
woven could be used for a reinforcing material.
[0075] If the reinforcing material (11) comprises the reinforcing
fibers or reinforcing wires (referring to FIG. 7), a strip
reinforcing material (10) will be made by aligning the plural
reinforcing fibers or the plural reinforcing wires (11) side by
side each other and their whole configuration forming a strip.
[0076] The second laminated tape (12) is made by mounting the
expansive graphite tape (60) on one side or both sides of the strip
reinforcing material (11). Any type of adhesive can be used to
combine the strip reinforcing material (11) with the expansive
graphite tape (60).
[0077] Although the thickness of the second laminated tape (12) is
not particularly limited, it can be, for example, 0.2 mm when
applying the expansive graphite tape (60) on one side of the
reinforcing material (11), and 0.35 mm with the expansive graphite
tape on both sides of the reinforcing material (11).
[0078] Although the width of the second laminated tape (12) is not
particularly limited, preferably it is 10.about.20 mm in width, and
more preferably 15 mm in width.
[0079] When the second laminated tape (12) exceeds 20 mm in width,
its flexibility goes down, which makes it harder to wind around the
first laminated tape (4), and this results in uneven width where
the tape is overlapped in winding it. On the other hand, when the
second laminated tape (12) is less than 10 mm in width, the second
laminated tape (12) could be broken out in winding because the
allowable tensile strength of the second laminated tape (12)
extremely goes down.
[0080] The second laminated tape (12) is wound one time or twice
around the outer surface of the filament (20) (FIG. 6 shows one
time winding). Winding the second laminated tape twice further
enhances lubricating ability and sealing ability of the packing
material (2). In winding the second laminated tape (12) twice,
winding one of the second laminated tape (12) to the opposite
direction from winding the other second laminated tape (12) provide
equivalent durability and sealing ability with a shaft rotating
clockwise or anti-clockwise.
[0081] Preferably the second laminated tape (12) is wound so that
its side edge overlaps with the adjacent side edge of the tape
(12).
[0082] In the case of the second laminated tape (12) having the
expansive graphite tape (60) applied on just one side of the
reinforcing material (11), the second laminated tape (12) is
preferably wound around a filament (20) so that the reinforcing
material (11) will stay inside, in order to prevent the reinforcing
material (11) from being exposed on the outer surface of the
packing made.
[0083] A cord (3) in forms of knitted cord, braided cord, plaited
cord and such can be made by braiding with such packing material
(2) gained. To be more precise, by braiding with one or plural
pieces of the packing material (2), a cord in forms of knitted cord
such as a roundly knitted cord and a squarely knitted cord, and
braided cord (3) such as a roundly braided cord and a squarely
braided cord can be made. In addition to these, a cord (3) in a
shape of a double braided cord or a fasten cord can be made. In the
case of braiding cords, a spontaneous braiding method wherein four,
eight, sixteen or eighteen, twenty four or thirty two of the
braiding thread can be used.
[0084] The expansive graphite tape is wound outside of the cord
(3).
[0085] When PVA is used as an adhesive layer (8), it will be stayed
inside of the cord (3), but the PVA layer can be removed after
making the cord (3). Although the PVA layer surpasses as a
reinforcing material, as it has a characteristic which may easily
cause a stress relaxation, removing of this layer results in no
stress relaxation to occur to the cord (3). This also results in no
stress relaxation in the packing (1). Additionally, when a
reinforcing material is necessary is when the greatest tensile
force acts to the expansive graphite sheet (6), i.e., when the
filament (20) and the cord (3) are made. Therefore, there will be
no problem even if the PVA layer is removed after constructing the
cord (3).
[0086] When removing the PVA layer, soaking of liquid resin to the
cord (3) is preferable. This is for a portion at where the PVA
layer existed to make a space when removing the PVA layer. If the
cord (3) is soaked in the liquid resin, the space can be filled
with the liquid resin. By filling the space with the liquid resin,
passing through of fluid from the inside of the cord (3) can be
prevented when using the packing (1) inside of the stuffing box.
Therefore, sealing ability of the packing (1) can be enhanced.
[0087] As for the liquid resin for soaking the cord (3), for
example, fluorocarbon resin such as polytetrafluoethylene (PTFE),
silicone resin, water-soluble phenolic resin, and emulsion resin
including inorganic pulverized powder such as glass, alumina,
silica gel, micromica, graphite and titanium can be used. Also, for
the cord (3), more than one or two liquid resin selected from a
group comprising these liquid resins can be soaked into. As a
soaking method, for example, normal soaking, soaking with heat or
soaking in vacuum can be employed.
[0088] The packing (1) can be gained by a pressuring of this cord
(3). The packing (1), for example, as shown in FIG. 12, is made in
a ring shape. The ring-formed packing (1) is packed into a stuffing
box and used suitably as a packing for shaft sealing of fluid
apparatus. The packing (1), as aforementioned, has a structure
wherein the expansive graphite tape (60) positions on the surface
thereof. Therefore the packing (1) can be made to have outstanding
lubricating ability, sealing ability, abrasion resistance, physical
strength and corrosion resistance.
[0089] When the gland packing (1) comprises the packing material
(2) without the reinforcing core (9), this gland packing (1) can be
generally used for pressured fluid at 150.about.2,500 psi (e.g.,
packing for a valve), and have sufficient durability and
lubricating ability (for lower torque) under this condition. An
example of the use of the packing for pressured fluid at 1,500 psi
is for petroleum factories or petroleum/chemistry factories. An
example of that for pressured fluid at 2,500 psi is for atomic
power stations.
[0090] When the gland packing (1) comprises the packing material
(2) with the reinforcing core (9), this gland packing can be
generally used for pressured fluid at 150.about.4,500 psi (e.g.,
packing for a valve), and have sufficient durability and
lubrication (for lower torque). An example of the use of the
packing for pressured fluid at 4,500 psi is for thermal power
stations.
[0091] In above-mentioned every embodiment, the gland packing (1)
has sufficient lubricating ability and durability even if it is
used for any fluid apparatus (e.g., pump) in which a shaft rotates
at high speed (more than 25 m/sec at the surface of the rotation
shaft).
[0092] The following is to explain the second embodiment of the
present invention. FIG. 13 shows a packing material described in
the second embodiment.
[0093] The packing (2) described in the second embodiment is made
by winding a third laminated tape (21) around the filament (20)
used in the first embodiment, which is made by mounting the
expansive graphite tape (6) on one side or both sides of the plain
state carbon fiber (7), instead of the second laminated tape (12)
in the first embodiment.
[0094] The filament (20) can be the same as that used in the first
embodiment.
[0095] Use of the third laminated tape (21) is the same as that of
the first laminated tape (4).
[0096] In the case of the third laminated tape (21) comprising the
expansive graphite tape (6) mounted on just one side of the plain
state carbon fiber (7), it is preferable that the third laminated
tape (21) is wound so that the plain state carbon fiber (7) will
stay inside, in order to prevent the plain state carbon fiber (7)
from being exposed outside of the packing made.
[0097] Similarly to the first embodiment, the filament (20) may
have a construction wherein the filament (20) is twisted so that
the filament (20) covers the reinforcing core (9). The material of
the reinforcing core (9) can be the same as that in the first
embodiment.
[0098] The packing (2) in the second embodiment also delivers
equivalent advantages to what the packing in the first embodiment
delivers.
Embodiment
[0099] Effects of the present invention will be clarified by
description of the embodiment for the packing material of this
invention. The packing material of the present invention is not
limited to the following embodiment.
Embodiment
[0100] The packing material of the present invention is made as the
following, and the gland packing of this embodiment is obtained by
pressuring of the packing material. In this embodiment, the packing
material of the second embodiment is made.
[0101] At first, the first laminated tape is made by mounting and
unifying an expansive graphite tape on the both sides of a plain
state carbon fiber, and then the first laminated tape is twisted so
that the first laminated tape covers the reinforcing core, which
results in a filament.
[0102] An inconel wire is used for the reinforcing core, which is
0.25 mm in diameter.
[0103] The plain state carbon fiber is 0.02 mm in thickness and 20
mm in width.
[0104] The expansive graphite tape is 0.2 mm in thickness and 20 mm
in width.
[0105] After that, the third laminated tape is gained by mounting
an expansive graphite tape on one side of a plain state carbon
fiber made from plain woven, and then the third tape is wound
around the filament, which results in a packing material, of which
cross-section is square, wherein the third laminated tape is wound
so that the expansive graphite tape stays outside. Each side of the
square packing material is 6.5 mm in length.
[0106] The plain state carbon fiber used in the third laminated
tape has the same thickness and width as that used in the first
laminated tape, and also the thickness and the width of the
expansive graphite tape used in the third laminated tape is the
same as those used in the first laminated tape.
[0107] Finally, the packing material is braided and pressured,
which results in a ring-shaped gland packing.
Comparative Test 1
[0108] FIG. 19 is a schematic cross-sectional view of the packing
material used in Comparative Test 1.
[0109] As shown in FIG. 19, a packing material (32) is made by
covering a cord (33) which is made by mounting expansive graphite
tapes with inconel wires (31). The cross-section of the cord (33)
is square, and each side of the packing material is 9.38 mm in
length. The inconel wire is 0.12 mm in diameter. Each side of the
square packing material (32) is 9.5 mm in length.
[0110] After that, the packing material (32) is braided and
pressure made, which results in a ring-shaped gland packing.
Comparative Test 2
[0111] FIG. 20 is schematic cross-section of the packing material
used in Comparative Test 2.
[0112] As shown in FIG. 20, a packing material (37), of which
cross-section is square, is made by braiding filaments (36),
wherein inconel wires (35) are braided around and covers a thinly
sliced expansive graphite tape (34). The expansive graphite tape is
0.29 mm in thickness, and its width after sliced is 6.5 mm. The
inconel wire is 0.10 mm in diameter, and each side of the square
packing material (37) is 9.5 mm in length.
[0113] After that, the packing material (37) is braided and
pressure made, which results in a ring-shaped gland packing.
(Test Method)
[0114] The ring-shaped gland packing of the embodiment, Comparative
Test 1 or Comparative Test 2 is packed into a stuffing box. Sealing
ability, lubricating ability and pressure resistance of each gland
packing with a shaft (a valve shaft) passing through the packing is
tested by sliding the shaft back and forth repeatedly.
[0115] Leakage for sealing ability, resistance against sliding of
the shaft for lubricating ability (changing the direction of
sliding and one way sliding) and change in pressure between the
packing and the shaft for pressure resistance are checked.
[0116] The number of 1 cycle of sliding back and forth is 2,500,
and 6 cycles are repeated, in total 15,000 times of sliding back
and forth (refer to FIG. 14). Hot water is used in each test as
pressure fluid. The temperature in the stuffing box is 350.degree.
C. In regard to the shaft movement, the stroke of the movement is
50 mm, and the speed of the movement is 25 mm/sec, and idling time
at the end of the movement is 1 sec, and number of repeat of the
movement is 2,500.times.6 cycles as aforementioned.
[0117] The result of each experiment is shown in FIG. 15 to FIG.
18. FIG. 15 shows leakage, FIG. 16 shows resistance against sliding
at change in the direction of the shaft movement, FIG. 17 shows
resistance against sliding during one way moving of the shaft and
FIG. 18 shows change in pressure between the packing and the
shaft.
(Test Result)
[0118] As the leakage data shown in FIG. 15, the leakage is
consistently close to zero with the gland packing of the embodiment
during experiment, on the other hand, the leakage is consistently
higher with that of Test 1. The leakage with the gland packing of
Test 2 starts after 5,000 times movement of the shaft and it is
rapidly grown up. Therefore, the gland packing of the embodiment
has better and longer lasting sealing ability than other gland
packings under high temperature and high pressure.
[0119] As the data of resistance against sliding of the shaft in
FIG. 16 and FIG. 17, the resistance against sliding of the shaft
with the gland packing of the embodiment is consistently lower than
that with the gland packing of Test 2, and after 1,500 times
movement of the shaft, the resistance of the embodiment is
certainly lower than that of Test 1. The difference of the
resistance between the embodiment and Test 1 grows up as the number
of the shaft movement. Therefore, the packing of the embodiment has
better and longer lasting lubricating ability than the others under
high temperature and high pressure.
[0120] As the data of change in pressure between the packing and
the shaft in FIG. 18, the pressure between the packing and the
shaft of the embodiment is consistently higher than the others.
Therefore, the gland packing of the embodiment has better and
longer lasting pressure resistance than the others under high
temperature and high pressure.
[0121] The packing materials as set forth in claim 1 and 2 are
durable enough under high temperature and high pressure as well as
under room temperature and lower pressure, and their high
lubricating ability (for lower torque) long lasts in the condition.
Besides, because of no exposure of fibers of the plain state carbon
fiber out of the surface of the packing material, there is no
worn-out of a shaft where the packing material is used.
[0122] Therefore, the packing material can be used in either way
for a valve or pump with high performance.
[0123] Any gland packing packed into a stuffing box can be made
with just one type of the packing material, because of high
performance in terms of pressure resistance, heat resistance and
lubricating ability the packing material has.
[0124] The packing materials as set forth in claim 3 and 4 have
further enhanced durability and can be used in higher pressure
[0125] The gland packing as set forth in claim 5 to 8 are durable
enough under high temperature and high pressure, and their high
lubricating ability (for lower torque) long lasts in the condition
as well as when it is used in room temperature and lower
pressure.
[0126] Therefore, the gland packing can be used in either way for a
valve or pump with high performance.
[0127] Just one type of the gland packing is enough for use when it
is packed into a stuffing box, because the gland packing has high
performance in terms of pressure resistance, heat resistance and
lubricating ability.
* * * * *