Textiles: spinning – twisting – and twining – Strand structure
Reexamination Certificate
2001-08-15
2004-03-23
Calvert, John J. (Department: 3765)
Textiles: spinning, twisting, and twining
Strand structure
C057S210000
Reexamination Certificate
active
06708479
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a braiding yarn made of expanded graphite for a gland packing which is to be used in a shaft seal part of a fluid apparatus or the like, and more particularly to a braiding yarn made of expanded graphite which can enhance the pressure resistance of a gland packing.
BACKGROUND ART
Conventionally, as a braiding yarn for a gland packing which is to be used in a shaft seal part of a fluid apparatus or the like, known is, for example, a braiding yarn
3
shown in FIG.
13
. In the braiding yarn
3
, a plurality of reinforcing fibers
2
,
2
are embedded in the longitudinal direction with forming gaps in the width direction of an expanded graphite tape
1
of a predetermined width.
In the case where a plurality of braiding yarns are braided to obtain a gland packing, it may be requested to twist the braiding yarn
3
as shown in
FIG. 14
in order to satisfactorily conduct the braiding.
However, the expanded graphite tape
1
is low in tensile strength and brittle, and edges of both end portions
1
a
,
1
b
in the width direction have low flaking resistance among expanded graphite particles. In edges of both end portions
1
a
,
1
b
in the width direction, namely, expanded graphite particles easily flake off In the case where the braiding yarn
3
of the inner-reinforce type is twisted to obtain a twisted braiding yarn
10
made of expanded graphite, moreover, large tensile and shearing forces act on the edges of both end portions
1
a
,
1
b
in the width direction, and hence cracks are formed with starting from the edges of both the end portions
1
a
,
1
b
in the width direction. Therefore, expanded graphite particles in and in the vicinity of the edges of both the end portions
1
a
,
1
b
in the width direction flake off.
When a plurality of braiding yarns
10
made of expanded graphite having a twisted structure are braided or twisted in a state where expanded graphite particles flake off in this way, flaking of expanded graphite particles is further advanced during the braiding or twisting process.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a braiding yarn made of expanded graphite in which flaking of expanded graphite particles is reduced or prevented from occurring.
In order to attain the object, the braiding yarn made of expanded graphite according to the invention is characterized in that, in a braiding yarn made of expanded graphite which is to be used in a gland packing, the braiding yarn is twisted so that at least one end portion in a width direction of a braiding yarn base material in which reinforcing fibers are embedded in an expanded graphite tape is directed toward an inner side in the width direction of the braiding yarn base material. According to the invention, since a twisting process is performed so that at least one end portion in the width direction of a braiding yarn base material is directed toward the inner side in the width direction of the braiding yarn base material, large tensile and shearing forces do not directly act on the edges of the one end portion during a twisting process, and hence occurrence of cracks from the edges of the one end portion and flaking of expanded graphite particles due to the occurrence of cracks can be reduced.
The other braiding yarn made of expanded graphite according to the invention is characterized in that, in a braiding yarn made of expanded graphite which is to be used in a gland packing, the braiding yarn is twisted so that at least one end portion in a width direction of a braiding yarn base material in which reinforcing fibers are embedded in an expanded graphite tape is directed toward an inner side in the width direction of the braiding yarn base material and a portion between both end portions in the width direction is bent. According to the invention, in addition to the function that, during a twisting process, large tensile and shearing forces do not directly act on the edges of the one end portion and occurrence of cracks from the edges of the one end portion and flaking of expanded graphite particles due to the occurrence of cracks can be reduced, since the portion between both the end portions in the width direction of the braiding yarn base material is bent, the dimension in the width direction of the braiding yarn base material can be reduced, the twisting process is facilitated, and twisting workability can be improved.
The further braiding yarn made of expanded graphite according to the invention is characterized in that, in a braiding yarn made of expanded graphite which is to be used in a gland packing, a braiding yarn base material in which reinforcing fibers are embedded in an expanded graphite tape and part of expanded graphite particles on a side of a surface of the expanded graphite tape are removed by a blasting process and is twisted. According to the invention, part of expanded graphite particles which are on the side of the surface of the expanded graphite tape, and which are highly oriented at a high density where cracks easily occur are removed by the blasting process. During the twisting process, even when a large tensile force acts on the end portions in the width direction of the braiding yarn base material, therefore, occurrence of cracks from the end portions and flaking of expanded graphite particles due to the occurrence of cracks can be reduced.
The still further braiding yarn made of expanded graphite according to the invention is characterized in that, in a braiding yarn made of expanded graphite which is to be used in a gland packing, the braiding yarn is twisted so that at least one end portion in a width direction of a braiding yarn base material in which reinforcing fibers are embedded in an expanded graphite tape and part of expanded graphite particles on a side of a surface of the expanded graphite tape are removed by a blasting process and is directed toward an inner side in the width direction of the braiding yarn base material. According to the invention, in addition to the function that, during the twisting process, large tensile and shearing forces do not directly act on the edges of the one end portion and occurrence of cracks from the edges of the one end portion and flaking of expanded graphite particles due to the occurrence of cracks can be reduced, since part of the expanded graphite particles which are on the side of the surface of the expanded graphite tape, and which are highly oriented at a high density where cracks easily occur are removed by the blasting process, a function that, during the twisting process, even when a large tensile force acts on both end portions in the width direction of the braiding yarn base material, therefore, occurrence of cracks from the end portions and flaking of expanded graphite particles due to the occurrence of cracks can be reduced is added. Consequently, occurrence of cracks and flaking of expanded graphite particles due to the occurrence of cracks can be reduced more surely.
The still further braiding yarn made of expanded graphite according to the invention is characterized in that, in a braiding yarn made of expanded graphite which is to be used in a gland packing, the braiding yarn is twisted so that at least one end portion in a width direction of a braiding yarn base material in which reinforcing fibers are embedded in an expanded graphite tape and part of expanded graphite particles on a side of a surface of the expanded graphite tape are removed by a blasting process is directed toward an inner side in the width direction of the braiding yarn base material and a portion between both end portions in the width direction is bent. According to the invention, in addition to the function that, during the twisting process, large tensile and shearing forces do not directly act on the edges of the one end portion and occurrence of cracks from the edges of the one end portion and flaking of expanded graphite particles due to the occurrence of cracks can be reduced, since the portion between both end portions in the width direction is bent, the di
Fujiwara Masaru
Ikeda Takashi
Calvert John J.
Hurley Shaun R
Jones Tullar & Cooper P.C.
Nippon Pillar Packing Co. Ltd.
LandOfFree
Braiding yarn made of expanded graphite does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Braiding yarn made of expanded graphite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Braiding yarn made of expanded graphite will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3284622