JP2006161831A - Diaphragm and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm capable of maintaining high strength and achieving a long service life even under severe environmental conditions, for example, the environmental conditions such as temperature and pressure exceeding 150°C and 1 MPa, respectively, and to provide its manufacturing method. <P>SOLUTION: A reinforced fiber cord 2 is arranged inside main body rubber 1, and openings 3, 4 for mounting a tightening device for attaching to a diaphragm valve main body are formed. The reinforced fiber cords 2 positioned around the openings 3, 4 are arranged with high density without being cut. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a diaphragm and a manufacturing method thereof, and more specifically, a diaphragm in which a reinforcing fiber cord is disposed inside a main body rubber, and an opening for mounting a fastener for attaching to a diaphragm valve main body is formed. About.

  Diaphragm valves are used in many fields because they can seal fluid easily, reliably and inexpensively. The diaphragm used for the diaphragm valve is mainly made of rubber or resin, but may contain reinforcing fibers. This reinforcing fiber regulates that the rubber or resin constituting the diaphragm is stretched and deformed to prevent the rubber or resin from being prematurely damaged. It is effective when used in an environment.

  The shape of the diaphragm is generally a square, a rectangle, a disk shape, etc., and in each case, the central part is curved and bulges to one side, and this central part is inverted so that the fluid is sealed, so it is a fixed part. A large stress is applied to the outer peripheral portion and the curved central portion, and this portion is most likely to be damaged.

Therefore, various devices have been devised to reinforce such a part, and a diaphragm valve provided with a protrusion on the valve side for fixing the outer periphery of the diaphragm (Patent Document 1), a deformation prevention ring on the outer periphery of the diaphragm A diaphragm valve (Patent Document 2) or the like in which a slab is arranged has been proposed.
JP-A-11-210902 JP-A-5-196200

  However, the configuration of the diaphragm valve of the above-mentioned prior art is effective when the seal pressure is low or the fluid temperature is low. However, under more severe conditions, for example, the temperature reaches 150 ° C. and the pressure reaches 1 MPa or more. When used in an environment, there is a problem that the diaphragm cannot be tolerated and breaks at an early stage, and there is a strong demand for realizing a diaphragm valve with higher strength.

  Moreover, even if a diaphragm containing a reinforcing fiber is used, it is necessary to provide a through hole for attaching a fastener to be fastened to the valve body at the outer peripheral portion and the central portion of the diaphragm. As a result, the reinforcing fibers are cut, and a significant decrease in strength is inevitable.

  Furthermore, when used in the middle of steam piping, the rubber material that is the main material is also a peroxide vulcanized material such as fluorine rubber, EPDM (ethylene propylene rubber) or HNBR (hydrogenated acrylonitrile butadiene rubber), etc. However, it is generally difficult to bond the rubber material and the reinforcing fiber, and particularly the adhesive strength at high temperature is low, so that it is difficult to manufacture a high quality diaphragm.

  Therefore, in view of the above-mentioned problems of the prior art, an object of the present invention is a diaphragm that can maintain high strength and have a long life even under severe environmental conditions, for example, environmental conditions exceeding a temperature of 150 ° C. and a pressure of 1 MPa. And providing a manufacturing method thereof.

  The above object can be achieved by the invention described in the claims. That is, the diaphragm according to the present invention is characterized in that a reinforcing fiber cord is disposed inside the main body rubber, and an opening for attaching a fastener for attaching to the diaphragm valve main body is formed, and is positioned around the opening. The reinforcing fiber cords are arranged at a high density without being cut.

  According to this configuration, since the fiber reinforcement cord around the opening where the fastener is mounted is not cut and is arranged at a high density, even if it is used by being mounted on the diaphragm valve body, Can be effectively prevented, and in particular, the diaphragm has excellent durability even under severe environmental conditions such as high temperature and high pressure.

  As a result, it was possible to provide a diaphragm that can maintain high strength and have a long life even under harsh environmental conditions such as a temperature exceeding 150 ° C. and a pressure of 1 MPa.

  It is preferable that the main body rubber is fluororubber and the reinforcing fiber cord is an interdigital aramid fiber composed of medium fibers.

  According to this configuration, the fluororubber that constitutes the main rubber and the aramid fiber that constitutes the reinforcing fiber cord can both maintain high strength even in harsh environments. Therefore, it becomes easy to form the opening while drilling, the manufacturing yield is improved, the manufacturing cost is reduced, and the durability is further enhanced. In particular, when an aramid fiber is used in which the fibers are twisted together, the fiber filament protrudes from between the reinforcing fiber cords, and this bites into the main rubber, thereby reinforcing the integrity of the reinforcing fiber and the rubber. As a result, the adhesive force with the covering rubber can be maintained high without using an adhesive.

  In addition, the characteristic configuration of the diaphragm manufacturing method according to the present invention is that unvulcanized rubber is injected into a mold, a reinforcing fiber cord is disposed on the unvulcanized rubber, and further unvulcanized rubber is injected. In the method for manufacturing a diaphragm, in which the reinforcing fiber cord is disposed inside the rubber by covering the reinforcing fiber cord, and an opening for attaching a fastener for attaching to the diaphragm valve body is formed, the reinforcing fiber positioned around the opening The opening is perforated so that the cords are arranged at a high density without being cut.

  According to this configuration, it is possible to provide a method for manufacturing a diaphragm that can maintain high strength and have a long life even under severe environmental conditions, for example, environmental conditions that exceed a temperature of 150 ° C. and a pressure of 1 MPa.

  It is preferable to use fluororubber as the unvulcanized rubber and interdigital aramid fibers composed of medium fibers as the reinforcing fiber cord.

  According to this configuration, it is easy to open while perforating, the manufacturing yield can be improved, the manufacturing cost can be reduced, and a method for manufacturing a diaphragm with higher durability can be provided. In particular, since high-strength aramid fibers that are difficult to cut can be arranged without punching / cutting, troublesome punching / cutting work is not required and workability is improved.

  In order to form the opening, unvulcanized rubber is injected into the mold in the previous period and a reinforcing fiber cord is disposed on the unvulcanized rubber, and then a tapered drilling jig is attached to the reinforcing fiber cord around the opening. It is preferable to insert it so as to spread it out.

  According to this configuration, the reinforcing fiber cord is reliably prevented from being cut, and a high region of the reinforcing fiber cord can be easily formed around the opening.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially broken plan view illustrating the arrangement of reinforcing fibers of a diaphragm according to the present embodiment (the hatched portion is a broken portion), and FIG. 2 is a cross section of the diaphragm when used for a diaphragm valve. The structure is shown.

  As shown in FIGS. 1 and 2, the diaphragm D has a configuration in which a fluorine rubber is used as the main body rubber 1, and interdigital aramid fibers that are substantially orthogonal to the two directions are disposed therein as the fiber reinforcement cord 2. . This aramid fiber is preferably a medium fiber rather than a short fiber or long fiber, and such an aramid fiber does not need to be coated with a rubber material of the same quality in order to reinforce the adhesive strength with the main rubber. The interdigital aramid fibers can be placed in the main rubber as they are as aramid fiber cords (non-dip cords).

  Here, the medium fiber is not a long fiber composed of a single elongated filament, but fibers having a medium length that is not a short fiber cut to a few mm to 1 mm or less are twisted together. It means a fiber that becomes a long single spun yarn such as a filament, and has a structure in which the end of the fiber protrudes in a fluff shape from the outer peripheral surface. Specifically, Technora (trade name, manufactured by Teijin Ltd.) is preferable as such a medium fiber, and when this is adopted, it is excellent in adhesion to fluororubber used as a main rubber and requires a special adhesive. And can be integrally formed firmly. As a result, a long-life diaphragm can be realized even for a high-temperature and high-pressure diaphragm valve used at an operating pressure of 0.3 MPa or higher at a temperature of 100 ° C. or higher. Further, a high temperature of about 150 ° C., 1 MPa or higher, etc. Even in a harsh atmosphere of high pressure, high strength can be maintained.

  In addition, openings 3 and 4 are formed in the vicinity of the central portion and around the four locations in order to fasten the fasteners to the diaphragm valve body, and the reinforcing fibers around the openings 3 and 4 are formed in the openings 3 and 4, respectively. The reinforcing fiber density in this portion is increased, and the structure has a high reinforcing effect. That is, the reinforcing fiber cord around the openings 3 and 4 has a feature that a cut end is not exposed to the openings 3 and 4 and a region having a high reinforcing fiber cord density is formed around the openings. Since the periphery of the opening is firmly reinforced in this way, in the conventional technology, even if it is necessary to use 6 to 8 fasteners, the number of fasteners is changed to 4 according to the configuration of this embodiment. Even a sufficient fastening force can be obtained.

  Moreover, with such a configuration, the labor for punching or cutting high-strength aramid fibers that are difficult to punch can be saved, and an increase in cost due to the short life of the punching tool can be reliably prevented.

  Next, the manufacturing method of the diaphragm D of this embodiment is demonstrated. First, unvulcanized fluororubber is injected into a mold and solidified, and then aramid fiber cords coated with fluororubber are arranged in a lattice pattern. In this case, it is not necessary to arrange the aramid fiber cords densely, and the aramid fiber cords are arranged so that a gap of about several mm is formed.

  In this state, using a perforated jig having a tapered rod shape with a sharp tip, the tip is brought into contact with the opening position of the diaphragm D, and the reinforcing fiber cord around the opening is inserted and drilled. Thus, the openings 3 and 4 for fastening the diaphragm to the diaphragm valve main body via the fastener are formed. In this way, as shown in FIG. 1, the reinforcing fiber cords around the opening are gathered at high density without being cut around the opening, thereby forming a high reinforcing structure.

  Then, unvulcanized fluororubber is injected into the mold with the drilling jig inserted, and all the reinforcing fiber cords are covered and solidified, and then the drilling jig is pulled out.

  The mold may be circular or square, and therefore the shape of the diaphragm D may be circular or square, and the shape can be variously modified depending on the use mode.

  Since the diaphragm D of the present embodiment is manufactured in this manner, the mold used in the conventional manufacturing method is used as it is simply by preparing a drilling jig having a tapered rod shape with a sharp tip. It is possible to manufacture a diaphragm having high strength and durability without causing a significant increase in manufacturing cost.

Below, the diaphragm according to the present embodiment is used as an example, and the results of performing a durability test together with a comparative example will be described.
Example 1 A disk-shaped diaphragm (diameter: about 140 mm, thickness: about 6 mm) installed in a 40A pipe (diameter: about 40 mm) having a shape as shown in FIG. 1 was produced. Insertion holes (openings) for inserting bolts, which are fasteners, are provided at four locations around the periphery, and fluorocarbon rubber having a hardness of 65 ° (Shore A) is used for both the main body rubber and the covering rubber. An aramid fiber cord (technola, trade name) produced from medium fibers was disposed at the center of the diaphragm in the thickness direction. The aramid fiber cord has characteristics of 440 dtex / 1 × 2 (twisted 440 dtex fibers), breaking strength of about 150 N, breaking elongation of about 7%, and a reinforcing fiber cord having a diameter of about 0.35 mm. The surroundings are coated with a fluororubber of the same quality as the main rubber and the coated rubber so as to have a thickness of 0.6 mm, and are arranged in an interdigital shape at a density of 15/25 mm. The opening at the four peripheral locations uses a conical drilling jig with a diameter of about 15 mm with a tapered tip, and the opening at the center uses a drilling jig with a diameter of about 7 mm without cutting the fiber. Formed.
(Comparative Example 1) Aramid fiber cords similar to those in Example 1 were arranged so as to be orthogonal to each other as shown in FIG. A bolt D insertion hole was punched out with a punch, and a diaphragm D ′ in which a bolt insertion hole with a diameter of 7 mm was punched out with a punch at the center was produced. In FIG. 3, the hatched portion is a broken portion.
(Comparative Example 2) Aramid fiber cords similar to those of Example 1 were partially broken as shown in FIG. A diaphragm D ″ having a through hole was produced. In FIG. 4, a horizontal line is given, but the portion is a broken portion.

  The diaphragms of the above examples and comparative examples were respectively attached to the diaphragm main body, contacted with steam at about 150 ° C., and repeatedly subjected to 1 MPa sealing pressure, the number of times until seal leakage occurred was measured. The results are shown in Table 1.

表１の結果より、実施例１のダイヤフラムは、比較例１、２に比べてシール漏れを生じるに至る繰り返し回数が格段に多く、耐久性に優れていることが分かる。

From the results shown in Table 1, it can be seen that the diaphragm of Example 1 has a significantly higher number of repetitions leading to seal leakage than Comparative Examples 1 and 2, and is excellent in durability.

[Another embodiment]
(1) In the above embodiment, an example in which the aramid fiber of the reinforcing fiber is coated with a rubber material that is the same quality as the main rubber of the diaphragm is shown. May be.
(2) In the above embodiment, the opening was formed using a drilling jig having a tapered tip, but instead, a protrusion for forming an opening was previously provided in the lower mold, Reinforcing fiber cords may be pushed and arranged so as to avoid this protrusion, and then unvulcanized rubber may be injected. Also by this method, since the reinforcing fiber is not cut around the opening, the substantially same effect as the above embodiment can be exhibited.

The partially broken top view explaining the diaphragm which concerns on one Embodiment of this invention II-II sectional view of FIG. Partially broken plan view of diaphragm according to comparative example Partially broken plan view of a diaphragm according to another comparative example

Explanation of symbols

1 Body rubber 2 Reinforcing fiber cord 3, 4 Opening

Claims (5)

In the diaphragm in which the reinforcing fiber cord is disposed inside the main body rubber and the opening for attaching the fastener for attaching to the diaphragm valve main body is formed, the reinforcing fiber cord positioned around the opening is cut. Diaphragm characterized by being densely arranged. 2. The diaphragm according to claim 1, wherein the main rubber is fluororubber and the reinforcing fiber cord is a comb-shaped aramid fiber composed of medium fibers. The unvulcanized rubber is injected into the mold, the reinforcing fiber cord is arranged on the unvulcanized rubber, and the unvulcanized rubber is further injected to cover the reinforcing fiber cord, thereby reinforcing the fiber cord inside the rubber. In the method of manufacturing a diaphragm for forming an opening for mounting a fastener for attaching to a diaphragm valve body, the openings are arranged so as to be arranged at a high density without cutting the reinforcing fiber cords located around the opening. A method for manufacturing a diaphragm, characterized in that a perforation is perforated. 4. The method for manufacturing a diaphragm according to claim 3, wherein fluorine rubber is used as the unvulcanized rubber and interdigital aramid fibers composed of medium fibers are used as the reinforcing fiber cord. In order to form the opening, unvulcanized rubber is injected into the mold in the previous period and a reinforcing fiber cord is disposed on the unvulcanized rubber, and then a tapered drilling jig is attached to the reinforcing fiber cord around the opening. The manufacturing method of the diaphragm of Claim 3 or 4 performed by inserting so that it may be spread.

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