JPH0261674B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for joining the ends of a patch for a hatch cover, and more specifically, the present invention relates to a method for joining the ends of a patch for a hatch cover. The present invention relates to a method for joining the ends of a hatch cover gasket that can maintain good sealing performance even at low tightening pressures.

Technical background of the invention and its problems In recent years, the number of chemical tankers transporting various chemicals has increased, and there is an increasing need to improve the safety of the operation of these ships. These chemical tankers are equipped with a hatch cover for loading and unloading chemicals, and a gasket is adhered to the periphery of the hatch cover to seal the filled chemicals.

As a patch for such a hatch cover,
Conventionally, gaskets made of rubber or asbestos have been used, but when these gaskets are made of rubber, the rubber may be attacked by chemicals and the sealing performance may deteriorate, and asbestos products In this case, if the hatch cover is repeatedly subjected to tightening and compression due to opening and closing, the sealing properties may deteriorate due to low resilience.

For this reason, asbestos-based braided packings impregnated with tetrafluoroethylene resin dispersion, tetrafluoroethylene fiber-based braided packings, or packings in which the surface of square rubber is covered with a tetrafluoroethylene resin fired film are used. There is. However, these braided packings lack elasticity and cannot handle a large tightening load for the hatch cover, so they do not have sufficient sealing performance, and the square rubber packings mentioned above have a problem with the coaming that protrudes from the hatch peripheral wall and comes into contact with the packing. There were problems in that the compatibility was poor, and if the combing was pressed strongly against the packing, the polytetrafluoroethylene resin fired film covering the square rubber could be destroyed, and the sealing performance was not sufficient.

In order to solve these problems, a packing as shown in FIG. 7 has been proposed. This packing uses a relatively small-diameter cylindrical rubber 6 having a hollow part 5 as a core, an unfired tape 11 of tetrafluoroethylene resin is wound around the outer periphery, and a chemical fiber braided body 8 is provided around the outer periphery. Furthermore, an unfired tape 9 of tetrafluoroethylene resin and a tetrafluoroethylene fiber braided body 10 are provided in this order on the outer periphery. The cylindrical rubber used as the core is made of chloroprene rubber, nitrile rubber, or the like.

However, in the packing described above, the core rubber is cylindrical with a small diameter, so if the coaming that protrudes from the circumferential wall of the hatch and contacts the packing is displaced from the center of the packing, the rubber core exists above the part where the combing contacts. As a result, the elastic effect of the rubber core body could not be expected, and the sealing performance of the packing material sometimes deteriorated significantly. In order to solve such problems, if the rubber core is made larger, the dimensions of the chemical fiber braided body 8 provided on the outer periphery of the rubber core inevitably become smaller.

By the way, the packing having the above-mentioned structure is used in an endless form by joining its ends. Conventionally, the ends of the packing are heated with the ends in contact with each other, and the ends are heated with a material having a low melting point. This has been done by melting chemical fibers and fusing them together, and then wrapping an unfired tetrafluoroethylene resin tape around the outer periphery of the joint that has been shrink-hardened by heating and melting.

However, in the above-mentioned method of joining the ends of the packing, first of all, because the chemical fibers are heated and melted and hardened at the joint, even if unfired tetrafluoroethylene resin tape is wrapped around the outer periphery of the joint. Even if it is rotated, the tightening stress due to the combing that contacts the seal will be different between the joint and other parts, resulting in the problem that uniform tightening stress cannot be obtained and sufficient sealing performance cannot be obtained. It was hot. Secondly, as mentioned above, if the size of the rubber core is increased in order to improve the sealing performance of the packing, the size of the chemical fiber braided body 8 will inevitably become smaller. There was a problem in that the bonding force at the joint of the packing became small. This is because, in the above joining method, the joining force is generated only by heating and fusing the chemical fiber braided body 8. Therefore, as long as the above joining method is adopted, the chemical fiber braided body 8 must be provided with a constant thickness.
In connection with this, the size of the rubber core cannot be increased, and therefore, if the combing comes into contact with a position shifted from the center of the packing, the sealing performance of the packing inevitably deteriorates. Thirdly, the unfired tetrafluoroethylene resin tape wound around the outer periphery of the joint is likely to be cut when combing hits it because the chemical fiber braided body 8 located inside it is hardened. There was a problem.

OBJECT OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above. Moreover, the size of the rubber core can be increased, and even if the combing comes into contact with the joint of the joint, the repair cloth wrapped around the joint will not be cut. The object is to provide an end joining method.

Summary of the Invention The method for joining the ends of a patch for a hatch cover according to the present invention covers a hollow rubber core with a fired polytetrafluoroethylene resin tube, a heat-melting fluororesin tube, or an unfired tetrafluoroethylene resin tape. When joining the ends of a hatch cover packing made of a chemical fiber braided body and a chemical-resistant fiber braided body as cushioning materials on the outer periphery, a connecting rod coated with adhesive is applied to the hollow part of the rubber core body at both ends. When inserted, an adhesive is applied to the end face of the rubber core body and the end face of the chemical fiber to join them, and then a repair cloth coated with adhesive is wound around the outer circumferential surface of this joined part.

In the hatch cover packing joined in the present invention, an unfired tetrafluoroethylene resin tape, a fired tetrafluoroethylene resin tube, or a heat A meltable fluororesin tube may be provided, and the chemical-resistant fiber braided body may be treated with a tetrafluoroethylene resin dispersion or a liquid sealing material such as liquid paraffin or silicone oil.

The method for joining the ends of the patch for a hatch cover according to the present invention uses the method described above instead of heat-sealing the chemical fibers as the cushion material, so that the tightening stress due to combing is applied to the entire circumference of the patch. It is uniform across the body, the size of the rubber core can be made large, and furthermore, the repair fabric of the packing will not be cut due to contact with the combing. Therefore, an endless hatch cover gasket with extremely excellent sealing properties can be obtained.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below based on embodiments shown in the drawings.

The hatch cover packing 1 joined by the joining method according to the present invention is a hatch cover packing for a chemical tanker, as shown in FIG. It is provided at the peripheral edge of the hatch cover 4. Note that 15 in the figure is combing. This packing 1 may have a structure as shown in FIG. 7, but preferably, as shown in FIG. A calcined tetrafluoroethylene resin tube or a heat-fusible fluorocarbon resin tube 7 with a diameter of The tape 9 and the chemical-resistant fiber braided body 10 are provided in this order.

Such a hatch cover packing 1 is made into an endless shape by joining its ends in the following manner. First, a connecting rod 1 whose outer peripheral surface is coated with adhesive is placed in the hollow part 5 of the rubber core body 6 to be joined to the packing 1.
2 is inserted, and an adhesive is applied to the bonding surface of the rubber core body 6 and the bonding surface of the chemical fibers for bonding. At this time, it is preferable that the connecting rods 12 are inserted into the packings to be joined by approximately the same length.

The connecting rod 12 is preferably formed in a cylindrical shape from the same rubber material as the rubber core 6, but in some cases, a surface-treated tetrafluoroethylene resin rod, metal rod, etc. may be used. You can also do that. Further, its shape is not limited to a cylindrical shape, but may have a shape having bulges 13 at both ends, as shown in FIGS. 4a and 4b.

As the adhesive applied to the outer circumferential surface of the connecting rod 12 and the joint surface of the rubber core body 6, it is preferable to use an epoxy adhesive, a phenol adhesive, or the like having solvent resistance. Further, as the adhesive applied to the bonding surface of the chemical fiber 8 as the cushion material, it is preferable to use a rubber adhesive or the like.

After joining both end surfaces of the packing 1 in this way, after leaving it for a certain period of time, for example, about 12 to 36 hours, as shown in FIG.
A repair cloth 14 whose inner peripheral surface is coated with adhesive is wound. The repair cloth 14 may include aromatic polyamide fibers having high strength, polyester fibers,
Cloths woven from polyolefin fibers, cotton, glass fibers, etc. are used, and among these, it is particularly preferable to use aromatic polyamide fibers in order to increase the bonding strength at the bonded portion.

As the adhesive applied to the inner circumferential surface of the repair cloth 14, a rubber adhesive is preferable.

By wrapping such repair cloth 14 around the outer peripheral surface of the joint, even if the combing comes into contact with the joint of the packing, it will not be cut unlike unbaked tetrafluoroethylene resin. An endless hatch cover gasket with excellent durability is obtained.

According to the present invention, the ends of the packing 1 are joined by the method described above, rather than by heating and melting the chemical fibers used as the cushioning material, so the dimensions of the rubber core 6 can be increased. The size of the chemical fiber used as a cushion material can be reduced. Specifically, the length of the rubber core body 6 in the cross-sectional radial direction can be 50 to 85%, preferably 65 to 85%, of the cross-sectional radial length of the packing. This value is very large compared to the above value of 40 to 45% for conventionally known packings. In this way, the length of the rubber core body 6 in the cross-sectional radial direction can be made 50 to 85% of the cross-sectional radial length of the packing, and as shown in FIG. Even if the combing 15 that contacts the packing 1 is shifted from the center of the packing 1, a sufficient sealing effect can be obtained. On the other hand, with conventionally known packings, when the combing comes into contact with a position shifted from the center of the packing, it is difficult to obtain a sufficient sealing effect because the rubber core body 6 is small.

Although the cross-sectional shape of the rubber core body 6 is preferably square, it does not necessarily have to be square, and may be elongated, oval, or oval, for example. Further, the rubber core body 6 is preferably formed of oil-resistant rubber such as chloroprene rubber or nitrile rubber, and its hardness is preferably about JIS A 50° to 70°.

The outer peripheral surface of the rubber core body 6 is covered by covering with a fired polytetrafluoroethylene resin tube or a heat-melting fluororesin tube, or by winding an unfired tetrafluoroethylene resin tape. , the thickness of the outer peripheral surface of this rubber core 6
It is preferable to cover with a 0.01 to 0.5 mm calcined tetrafluoroethylene resin tube or heat-melting fluororesin tube 7. Such a fluororesin tube 7 is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether.
PFA, FEP, a copolymer of tetrafluoroethylene and hexafluoropropylene, EPE, a copolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether, or tetrafluoroethylene and ethylene. is a copolymer of
A tube obtained by heating and melting a heat-melting fluororesin such as ETFE is used. A fired PTFE tube obtained by firing a tetrafluoroethylene resin can also be used.

The thickness of this fluororesin tube 7 is 0.01 to 0.5 mm as mentioned above, but if this thickness is less than 0.01 mm, it will be difficult to completely block out the vapors of low boiling point solvents, strong acids, strong alkalis, etc. This is undesirable because the rubber core body may be attacked by these vapors, and on the other hand, if it exceeds 0.5 mm, the tube itself becomes hard and its conformability to the rubber core surface decreases, which is undesirable.

On the outer periphery of the above-mentioned fluorocarbon resin tube 7, a chemical fiber braided body 8 as a cushion material, unfired
A PTFE tape 9 and a chemical-resistant fiber braid 10 are provided in this order. As the chemical fiber braided body 8 as the cushion material, a polypropylene fiber braided body, a polyethylene fiber braided body, etc. are used. It serves to protect the chemical fiber braided body 10 from being destroyed.

By wrapping the unfired PTFE tape 9 around the outer circumferential surface of the synthetic fiber braided body 8 as a cushioning material, it is possible to prevent harmful vapors such as low boiling point solvents from penetrating into the inside of the packing, although not completely. can. This green PTFE tape can also be treated with a lubricating oil.

Furthermore, instead of wrapping the unfired PTFE tape 9 around the outer periphery of the chemical fiber braided body 8 as a cushioning material in the packing 1 used in the present invention, the unfired PTFE tape 9 is formed by firing in the same way as the rubber core body 6 and covering. The braided body can also be covered with a fluororesin tube.

A chemical-resistant fiber braided body 10 is provided on the unfired PTFE tape, and this chemical-resistant fiber braided body 10 is made by braiding threads made by twisting together fibers such as tetrafluoroethylene fibers and polypropylene fibers. is used. This braided body 10 improves the sealing properties of the resulting packing by impregnating the fibers in advance with a liquid sealant such as tetrafluoroethylene resin dispersion, liquid paraffin, or silicone oil. be able to.

When covering the rubber core body 6 with the fluororesin tube 7 obtained by firing the rubber core body 6 in this way, the rubber core body is coated in a manner that prevents vapors of low boiling point solvents, strong acids, strong alkalis, etc. from penetrating into the rubber core body. Prevents swelling and deterioration of the body. On the other hand, in case of wrapping the unfired PTFE tape 11 around the rubber core 6, the unfired PTFE tape has more pinholes (tiny gaps) than the fluororesin tube obtained by firing. In addition, solvents with a boiling point lower than the gap between the stacked tapes are likely to penetrate, so it is inevitable that the rubber core will swell and deteriorate.

Effects of the invention The method for joining the ends of the patch for a hatch cover according to the present invention is based on the method described above, rather than by heating and fusing the chemical fibers as the cushion material. The endless shape has excellent sealing properties because it is uniform over the entire circumference, the size of the rubber core can be made large, and the repair cloth of the packing will not be cut due to contact with the combing. A gasket for a hatch cover is obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the essential parts of a chemical tanker with a packing attached thereto, FIG. 2 is a perspective view of a preferable packing used in the present invention, and FIG.
The figure is an explanatory diagram showing a method of joining the packing, FIG. 4 is a sectional view showing a modification of a connecting rod used in joining the packing, and FIG. 5 is an explanatory diagram showing the method of joining the packing. FIG. 6 is an explanatory diagram of the state of contact between the packing and the coaming, and the seventh
The figure is a perspective view showing an example of a packing joined according to the present invention. DESCRIPTION OF SYMBOLS 1... Gasket for hatch cover, 5... Hollow part, 6... Rubber core, 7... Fluorine resin tube, 8... Chemical fiber braided body, 10... Chemical resistant fiber braided body, 12... Connection Rod, 14... repair cloth,
15...Combing.

Claims (1)

[Claims] 1. A hollow rubber core body is covered with a fired polytetrafluoroethylene resin tube, a heat-melting fluororesin tube, or an unfired tetrafluoroethylene resin tape,
When joining the ends of the hatch cover packing, which has a chemical fiber braided body and a chemical-resistant fiber braided body as cushioning materials on the outer periphery, the connecting rod is coated with adhesive in the hollow part of the rubber core at both ends. The hatch cover is characterized in that the end face of the rubber core body and the end face of the chemical fiber are joined together by applying an adhesive, and then a repair cloth coated with adhesive is wrapped around the outer circumferential face of this joint part. How to join the ends of the packing.