JPS6084476A - Braided packing and preparation thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a braided backing and a method for manufacturing the same.
It's from Zuru-b.

Conventionally, braided backings have been used as sealing members for bearings of rotating equipment, sliding parts of valve stems, and the like. ,
There are two types of braided banking: one is a braided body made of asbestos yarn from the center to the outer periphery, and the other is a braided body made of asbestos yarn or other braided body from the center to the outer periphery. Generally, a braided backing with a core like the latter is used as a backing for a valve that requires high sealing performance.

In the known core-containing braided backing, the core is made of asbestos, graphite, etc., and a molding material mixed with a rubber binder, filler, etc. is extruded into a rod shape, and then the rod-shaped molded body is heated. The known braided backing having such a core, which is manufactured by drying, has the following problems.

■ 87 (nr!) The core made of the molding material is soft when extruded and molded. [Due to the quality, it was difficult to handle the core after molding as a long body.
For this reason, in the past, the core that had been formed and heated was cut into pieces into extremely short rod-like pieces, such as those for example, and the core that had become these rod-like pieces was cut into pieces. was manually (discontinuously) fed into a braiding machine, and the outer periphery of the rod-shaped piece was braided with Ico cotton yarn or the like and covered with a C jacket.

This J, sea urchin, in the conventional production method, the production of middle sea urchin.
Through the process of covering the outer sheath, the core or filament '4'
An unbroken long piece like rt* (p-n) 4. There was a vacancy in which it was not possible to construct a -v1 continuous manufacturing facility (i^) because it was difficult to handle it as such.

■ When carrying out extrusion molding of the core, in order to reduce the friction between the entire wall and the extruded molded product, the above-mentioned materials, binders, fillers, etc. are added to the molding material in advance. Although surfactants and extrusion aids are added, these surfactants and extrusion aids contained in the core may ooze out to the outer surface of the braided backing due to the action of high-temperature fluids, etc., during use of the braided backing. In recent years, when equipment has become increasingly automated, valves may become stuck to the sliding parts of equipment, resulting in equipment malfunction. (It is extremely dangerous if malfunction occurs.) ■ Valve backings generally have a ring-shaped outer sheath 1 that fits in only one place, as shown in Fig. 1, just like piston rings and spring washers. When using backings, several backings are slightly cut apart so that the cut parts 2 of each backing do not overlap with each other, but each backing has 3 cut parts 2 in the radial direction. It is desirable that there be no discontinuities other than the cut.
However, since the above-mentioned braided backing uses a short cut core 3, it is inevitable that discontinuities 4 will occur in the core at locations other than the cut portions. . Therefore, in the conventional bulkhead 4-d3, the discontinuous portion 4 of the center core becomes a passage for fluid, and there is a problem in that leakage occurs.

By the way, the conventional manufacturing method is <l IIJi and lJ
The cores are lined up in a row in the axial direction (they are fed into a tying machine, and a bag-knitted piece of silk is wrapped around the rows of cores to form a long string-like material. After forming the string-shaped body into a ring-shaped body, the ring-shaped body is cut at only one place in the 0=1 direction. When forming the cut portion 2, the cut portion 2 must match the seam of the core 3 in the outer cover 1 (in other words, the end surfaces of the two cores). Therefore, in the conventional braided backing, it was inevitable that a core discontinuity 4 would occur in the jacket 1.

An object of the present invention is to solve the above-mentioned problems by providing a method for producing a braided backing and the same.

In the braided backing of the present invention, the core is composed of a laminate of a graphite sheet with a swelling ratio and a silk-like material or a large number of flattened threads oriented in the -1 direction. Since it is much more elastic and longer than the core, there is no discontinuity in the core within the outer jacket.
Therefore, the backing of the present invention is a braided backing with better sealing performance than conventional products.

In addition, in the backing of the present invention, there is no need to extrude powder material when forming the core, so additives such as surfactants and extrusion aids are not contained inside the core. As a result, there is no risk of accidents caused by surface oozing of the surfactant or extrusion aid during use of the backing.

Furthermore, in the method of the present invention, when forming the core, the step of extruding the powder material and the step of heating and drying the core after extrusion molding are unnecessary, so the method of the present invention is more effective than the conventional method. Extremely high production efficiency and continuous production lol
It has the advantage of being suitable for one assembly.

In a preferred embodiment of the present invention, the core is constructed by winding a laminate of an expanded graphite sheet and a mesh body,
Therefore, although the core is dense, it has flexibility and elasticity, so it can be formed into a long rim instead of the conventional rl + core J, and therefore, even when a ring-shaped braided backing is formed, it can be formed into a long rim. There is no risk of discontinuities in the core inside the sheath, and there is no risk of leakage of fluid, etc.

Embodiments of the present invention will be described above with reference to the drawings.

FIG. 2 shows a cross-sectional view of one embodiment of the braided parapet of the present invention.

In the same figure, 5 is the outer covering 4 from the braided body, and 6 is the bulge 11.
The core consists of a laminate of a graphite sheet and a mesh body.

The outer cover 5 is made of asbestos thread, carbon-based thread, Kynor thread, or YJ Koseiyo polyamide thread, and is knitted into a cylindrical shape using GDR or a combination of yarns! 1 was given. After Part II, a lubricant treatment 1p is usually performed to impregnate the backing with an aqueous dispersion of tetrafluoroethylene resin, an aqueous silicone oil dispersion, or the like.

On the other hand, do the following for the center core 6! ! '! m is done.

That is, after laminating the expanded graphite sheet 7 and the net-like body 8 to make a laminated sheet using two pressure rolls, the laminated sheet of an appropriate width is rolled up into a spiral roll shape using a multistage 4-mining roll. The layered rolls are then molded using a compression molding roll to form an arbitrary cross-sectional shape having a predetermined density.In the case of a generally ring-shaped seal backing, the cross-sectional shape is preferably square or rectangular. So,
In this example, an elongated body (J5°C) which is molded to have a square I-side shape is made, and this elongated body is used as the core.

The silk-like body used in item 7 of the present invention is preferably made of stainless steel wire mesh (SUS316, wire diameter 0.1 mmφ), but it may also be made of other materials such as a perforated metal sheet. There may be. The mesh diameter of the net-like body is preferably in the range of 1 to 5011 n+, particularly preferably in the range of 2 to 5 mm. If the mesh diameter is less than 4 mm or more than 50 mIn, favorable results cannot be obtained in terms of sealing performance and elasticity when laminated with expanded graphite sheets. In addition, the expanded graphite sheet used for the core is manufactured by LJ CC2J [Graph Oil J (W
0.4Il1m) etc. are suitable.

The gist of the method of the present invention is the above-mentioned core manufacturing method θ, but the braided backing of the present invention is produced by following the core manufacturing process described above in the same manner as the known method for manufacturing braided backings. It is completed through a step of covering the core with an outer sheath made of a braided body, a molding step of forming the core covered with the outer sheath into a predetermined shape (for example, a ring shape), and a cutting step. The following comparative tests were conducted on the braided backing of the present invention produced by the above-described production method and the conventional braided backing under the same usage conditions.

The cutting v1 of the &111 backing used in the test had an inner diameter of 20
ml+, outer diameter 30mm, thickness 5mm, this backing was stacked as 5 control sets, and this was used as a reprint of 10kg.
Tighten the flow adjustment valve for f10n+2 to 1~1010 ruq.
1 installed at 0ko1, and this flow rate adjustment valve 1
Connected to a saturated steam line with a pressure of 0 kgf/cm2,
Perform 15 heating/cooling cycles of 6 hours of operation followed by 18 hours of rest under the condition of 4L+ of quaduator working pressure of 3 kof/cm'G.

That tII! In the case of the conventional product, a brown fluid seeped out from the 2nd cycle around the valve stem. Further, in the fourth or fifth cycle, the fluid began to solidify, and at the same time, the response of the actuator began to become disordered.

In contrast, with the backing of the present invention, no abnormality occurred until the end of the 15-cycle test, and the actuator operated normally until the end. As described above, unlike the core of conventional products, the braided backing of the present invention does not contain surfactants or extrusion aids in the core of conventional products. It has the unique property of not producing any internal exudates.

In addition, in the braided backing of the present invention, the core has bJ flexibility and elasticity, and there is no risk of breakage.
The braided backing of the present invention can be fed to the jacket braiding machine in its long form, and as a result, there is no discontinuity in the core in the final completed backing. It has a much higher sealing performance than A4-C.
There is.

Roughly, since the core that constitutes the braided backing of the present invention is composed of expanded graphite sheets 1 to 1 and a top layer C of a net-like material,
C1 The braided backing of the present invention can be manufactured using only a process such as LL-ru molding, without requiring processes such as heating drying and single cutting as in conventional methods. It has the advantage that it can be produced in a shorter process and time.

11i. According to the method of the present invention, a braided bag with higher performance than the conventional product can be produced at lower costs and with higher efficiency than the conventional method for the above-mentioned reasons. In other words, the method of the present invention does not require a heating drying process or core VJ cutting process as in the conventional method. Because it can be supplied to the coating process, we can produce braided backing without core discontinuities with higher efficiency and lower cost than conventional methods!
It is possible to make one.

a) 3. For the core, one 81-layer sheet is used as shown in the example shown.
]-Although it does not have to be rolled up in a roll shape, if it is rolled up and compression molded, the laminated sheets 1~ are laminated in the shape of sheets 1~ = (compression molded sheet J, rim adhesion is excellent and is the best from the standpoint of sealing performance.

In addition, as the net-like body used for the core, a lattice-like body having warp and weft threads is most suitable;
, line spacing of 1.25 mm).

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a known pulp backing with a core, and FIG. 2 is a cross-sectional view of eight sets of backings according to the present invention. 1...Outer cover, 2...Cut portion, 3...Inner core,
4... Discontinuous part, 5... Outer cover, 6... Core,
7... To the expanded graphite sea 1, 8... Reticular body. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A braided backing consisting of a rod-shaped center core and 1) an outer sheath made of a braided body that covers the outer periphery of the center core, and the center core is composed of an expanded graphite sheet and a net-like body or A braided backing comprising a laminate of a large number of parallel filaments in one direction. 2. A method for manufacturing a braided ballast consisting of a rod-shaped core and an outer sheath made of a braided body covering the outer periphery of the core, the method comprising: an expanded graphite sheet and a net-like body or a large number of unidirectional 'l'f'□i filament to form a laminated sheet; stacking the laminated sheets into a roll to form a laminated roll; and press-forming the laminated roll to obtain a C predetermined density. and forming a flexible core with an arbitrary cross-sectional shape that is loaded with a predetermined elasticity.