JPH11336725A - Apparatus and method for tightening flange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flange tightening device which can eliminate retightening work by preventing bolts and nuts for tightening a flange from loosening even if the temperature of high-temperature piping and the flange protrudingly- mounted on the end of the piping rise. SOLUTION: This flange tightening device 9 consists of a flange 1, a nut 3 sandwiching it from both outsides, a high-tension type washer 4 inserted between the flange 1 and the nut 3, and a bolt 2 passing through all of them integrally. The washer 4 is formed out of a material whose linear expansion coefficient is larger than that of the bolt 2 and the nut 3. Using the high-tension type washer 4, even if the flange 1 becomes hot and the bolt 2 gets longer due to heat, permits the high-tension type washer 4 to be heat-elongated more than it to pull the bolt 2, thus it is possible to prevent tightening from being loosened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flange fastening device and method for connecting flanges protruding from ends of a pipe through which a high-temperature fluid is passed.

[0002]

2. Description of the Related Art To connect high-temperature pipes 16, which are pipes through which a high-temperature fluid is passed, using a conventional flange fastening device 10 shown in FIG.
After the ring-shaped packing 18 is sandwiched between the flanges 11 protruding from the ends of the flanges 6, the flanges 11 are tightened at room temperature using bolts 12 and nuts 13. The high-temperature pipe 16 is formed of a material suitable for allowing a high-temperature fluid to pass therethrough. However, since general-purpose products are used for the bolts 12 and nuts 13, the flange 11 of the high-temperature pipe 16 and the bolts 12 and nuts 13 are mutually connected. Consists of dissimilar materials.

[0003]

As described above, in the fastening structure of the flange 11 in which the flanges 11 are connected at room temperature using only the bolts 12 and the nuts 13 made of different materials from each other, it is only after the connection that the flanges 11 are connected. When a high-temperature fluid flows into the high-temperature pipe 16 during use, the linear expansion coefficient of the material used for the flange 11 and the bolts 12 and nuts 13
The thermal expansion difference due to the difference in the coefficient of linear expansion of the material used for the above (larger than the coefficient of linear expansion of the flange 11) causes a phenomenon that the tightening by the bolts 12 and the nuts 13 is loosened. As a result, loose bolt 12 and nut 13
However, there is a problem in that it is necessary to retighten the work by hand, and the accompanying operation cost is also required.

[0004] The problem to be solved by the present invention is to obtain a flange tightening apparatus and method which does not require additional tightening even if the temperature of a high-temperature pipe rises once after tightening once at normal temperature. It is in.

[0005]

In order to solve the above-mentioned problems, the present invention uses the following means. The flange tightening device of the present invention is a flange tightening device in which high-temperature fluid is passed through and pipes connected to each other are connected by tightening flanges protruding from ends of these pipes. A bolt that penetrates the flange, a nut screwed to the end of the bolt, and an expansion that is made of a material having a larger linear expansion coefficient than the bolt and the nut, and is sandwiched between the nut and the flange. And a member.

The flange tightening method of the present invention is a flange tightening method for connecting pipes through which a high-temperature fluid is passed and which are connected to each other by tightening flanges protruding from ends of these pipes. After disposing an expansion member made of a material having a larger linear expansion coefficient than the bolt and the nut, between the nut and the flange screwed to the bolt penetrating the opposed flange,
At room temperature, the nut is tightened, the expansion member is sandwiched between the nut and the flange, and when a high-temperature fluid is passed through the pipe, the expansion member is thermally expanded more than the bolt and nut. In this case, the tightening state is maintained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
The flange fastening method and apparatus according to the embodiment will be described. FIG. 1 is a sectional view of a flange fastening device 9 according to a first embodiment of the present invention, and the flange fastening method according to the first embodiment is performed by this device 9.

In FIG. 1, a pipe 6 is a high-temperature pipe through which a high-temperature fluid can flow, and a connecting flange 1 is integrally protruded from the end of the pipe 6 over the entire circumference. The high-temperature pipes 6 to be connected adjacent to each other in the axial direction sandwich a ring-shaped packing 8 that does not block the fluid passage 7 of the high-temperature pipe 6 between the flanges 1. The flanges 1 are connected by tightening the flanges 1 using a flange tightening device 9. As a material of the packing 8 for preventing the internal fluid from flowing out from the fluid passage 7, synthetic rubber having high airtightness and heat resistance is preferable.

The flange tightening device 9 includes a nut 3 disposed on both outer sides of the opposed flange 1 and a flange 1.
And a bolt 2 penetrating through the nut 3 and a high tension type washer 4 as an expansion member interposed between the flange 1 and the nut 3. The washer 4 is made of a material having a larger linear expansion coefficient than the bolt 2 and the nut 3. 1, reference numeral 5 denotes a connection hole of the flange 1, and reference numeral 4a denotes a bolt hole of the washer 4. The bolt 2 may have a structure having a head at one end.

The method of assembling the flange fastening device 9 is performed as follows, as one example. First,
At normal temperature before operation of a large-scale heating facility or the like in a factory or the like, the bolt 2 is passed through the connection hole 5 of the flange 1 facing each other between the high-temperature pipes 6 to be connected. Next, the bolt through holes 4a of the high tension type washer 4 are fitted to and inserted into both ends of the bolt 2 with the flange 1 sandwiched from both outer sides. Finally, the nut 3 is screwed into both ends of the bolt 2 in such a manner that the high tension type washer 4 that has been passed through is pressed down from both ends.

In the flange fastening device 9 assembled at ordinary temperature in the above procedure and connecting the opposed flanges 1 to each other, the high-temperature fluid flows into the high-temperature pipe 6 with the operation of the piping system for the first time, Even if the temperature of the pipe 6 and the flange 1 protruding from the end thereof rises, the conventional problem does not occur.

That is, the high tension type washer 4 has a larger linear expansion coefficient than the bolt 2 and the nut 3, and the washer 4 thermally expands in the axial direction more greatly than the bolt 2, so that the bolt 2 thermally expands. Nevertheless, the resulting loosening of the bolt 2 can be removed by pulling the bolt 2 by the thermal expansion of the washer 4. In this way, the piping system connected by the flange fastening device 9 can reliably maintain the tightened state before the operation regardless of the flow of the high-temperature fluid due to the first use after the assembly at normal temperature.

For this reason, there is no need for the on-site worker to perform additional tightening work during operation, and as a result, labor costs can be reduced. The flange tightening device 9 which does not require such additional tightening is different from the conventional flange tightening device 10 only in that the number of high tension type washers 4 is increased. No complicated work is required for the tightening work. Therefore, it is possible to provide the flange fastening device 9 with a simple configuration and suppressing an increase in cost.

The present invention is not limited to the first embodiment. For example, the expansion member 4 that prevents the bolts 2 and the nuts 3 from being loosened by the above-described high tension action by thermal expansion is not limited to the washer but is sandwiched between the outer surface of the flange 1 and the nut 3 to perform the high tension action. Any material and shape may be used as long as the material can exhibit the characteristics.

[0015]

According to the flange tightening apparatus and method of the present invention, an expansion member made of a material having a larger linear expansion coefficient than a bolt or a nut is sandwiched between a flange and a nut of a high-temperature pipe at room temperature. When a high-temperature fluid flows through the high-temperature pipe for the first time, the bolt is pulled by the thermal expansion larger than the bolt and nut of the expansion member.
Since the nut is prevented from loosening, the necessity of retightening can be eliminated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flange fastening device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a conventional flange fastening device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flange 2 ... Bolt 3 ... Nut 4 ... High tension type washer (expansion member) 4a ... Bolt through hole 5 ... Connection hole 6 ... High temperature piping 7 ... Fluid passage 8 ... Packing 9 ... Flange fastening device

Claims (2)

[Claims] 1. A flange tightening apparatus for connecting pipes through which a high-temperature fluid is passed and connected to each other by tightening flanges protruding from ends of these pipes, wherein said pipes penetrate said opposed flanges. A nut to be screwed to an end of the bolt, an expansion member made of a material having a larger linear expansion coefficient than the bolt and the nut, and sandwiched between the nut and the flange; A flange fastening device comprising: 2. A flange tightening method for connecting pipes through which a high-temperature fluid is passed and connected to each other by tightening flanges protruding from ends of these pipes, wherein said flanges are opposed to each other. After disposing an expansion member made of a material having a larger linear expansion coefficient than the bolt and the nut between the nut and the flange screwed to the bolt penetrating the nut, the nut is tightened at room temperature to expand the expansion member. Sandwiching the member between the nut and the flange,
A flange tightening method, wherein when the high-temperature fluid is passed through the inside of the pipe, the expansion member is thermally expanded more than the bolt and nut to maintain the tightened state.