JP2001225231A - Clamping method and device for flange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To tighten bolts evenly and keep them in the tightened state without later retightening even when they elongate under high temperature, in flange- coupling piping and the like. SOLUTION: A bolt 4 is inserted into bolt holes 3 in flanges 2, and a nut 5 is mounted on the bolt 4. With the bolt 4 placed under tension by a bolt tensioner 7 and elongated, the tension applied to the bolt 4 is controlled so that the gap value that a gap measuring device 10 measures between the flange faces becomes a preset value. In this controlled condition, the nut 5 is tightened on the bolt 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fastening a flange in a pipe or the like with a plurality of bolts and nuts using a bolt tensioner, and an apparatus for fastening the same.

[0002]

2. Description of the Related Art To connect a pipe to a flange, a gasket is sandwiched between a pair of opposed flanges and tightened with a plurality of bolts and nuts. For this tightening, a tool such as an impact wrench or a torque wrench is generally used. . However, when the flange of the large-diameter pipe is tightened, the tightening between the bolts is likely to be uneven (that is, in a single tightened state), and this has been a main cause of leakage from the flange portion. Therefore, conventionally, the uniformity of the tightening is confirmed by measuring the gap between the flange surfaces with, for example, a skimmer gauge or the like. If the unevenness is not uniform, the tightening is corrected. FIG. 6 is a front view showing a flange portion of the pipe, and FIG. 7 is a diagram showing a surface portion of the flange. In these drawings, flanges 2 are respectively attached to ends of pipes 1 to be connected, and bolts 4 are inserted into a plurality (12 in this example) of bolt holes 3 provided at equal intervals in each flange 2.
Gasket 6 is interposed between the flange surfaces when tightening,
In this state, each bolt 4 is tightened with a nut 5.

[0003] The procedure of the above-mentioned flange fastening method will be described more specifically as follows. (1) Insert the two bolts 4 into the lower bolt hole 3 and attach the nut 5, and insert the gasket 6 so as to be aligned with the center of the flange surface. (Insertion of Gasket) (2) Insert the remaining ten bolts 4 into the bolt holes 3 and attach the nuts 5. (Attaching the bolts) (3) Tighten the bolts 4 in a diagonal order with a wrench.
(4) Tighten the bolts 4 in a diagonal order with a percussion wrench.
(Temporary tightening of bolts) (5) Tighten the bolts 4 with a torque wrench in diagonal order. (Full tightening of bolts) (6) Measure the distance between the flange surfaces with a skimmer at every 45 ° and record. (Measurement of the gap between the flange faces) (7) Tighten with the impact wrench while adjusting the gap between the flange faces. (8) Tighten the gap between the flange surfaces with a skimmer gauge at an angle of 45 °.
Measure and confirm each time. (Check the gap between the flange surfaces)

[0004]

In such a conventional flange tightening method, the gap between the flange surfaces is controlled by the tightening torque of the bolt 4, so that fine adjustment of the tightening is difficult and the adjustment accuracy is limited. There is. Further, in the case of a pipe through which a high-temperature liquid or gas flows, if the operation is started after the completion of the tightening operation, the pipe 1 becomes hot and the bolt 4 expands, and the tightening is loosened. Furthermore, since the bolt is adjusted with a striking wrench while measuring the gap between the flange surfaces with a gap gauge, there is a problem that the working efficiency is low. Accordingly, an object of the present invention is to solve such a problem, and an object of the present invention is to provide a new flange fastening method and a new fastening device.

[0005]

According to the present invention, there is provided a method for tightening a flange, comprising inserting a bolt into each bolt hole of the flange, applying tension to the bolt with a bolt tensioner, and elongating the bolt. The gap between the flange surfaces is measured by a gap measuring device, the tension applied to the bolt is controlled so that the value becomes a preset value, and a nut is attached to the bolt in this state ( Claim 1). According to the above method, since the tension applied to the bolt by the bolt tensioner is controlled so that the measured value of the gap between the flange surfaces becomes a preset value, the tightening can be performed efficiently with high accuracy. Further, since the bolts are tightened in a state where tension is applied, even if the bolts elongate due to the high temperature of the flange portion during operation, the bolts are not loosened and need not be retightened.

[0006] In the above method, a nut can be attached by simultaneously applying tension to each of the bolts inserted into the bolt holes on the diagonal line of the flange with a bolt tensioner (claim 2). When tension is applied to a plurality of bolts at the same time, tightening can be performed more accurately and quickly, and work efficiency can be further increased. In addition, a flange tightening device of the present invention for solving the above-mentioned problems includes a bolt tensioner for applying tension to a bolt by hydraulic pressure, a control valve provided on a hydraulic pipe for supplying hydraulic pressure to the bolt tensioner, and a gap between flange surfaces. And a control device for controlling the control valve such that the gap between the flange surfaces measured by the gap measuring device has a preset value. The present apparatus can be suitably used for carrying out the above-described method for fastening a flange of the present invention.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating a method of fastening a flange according to the present invention, FIG. 2 is an enlarged view of a bolt and a bolt tensioner in FIG. 1, and FIG. 3 is a front view showing the relationship between the flange in FIG. FIG. In these figures, flanges 2 provided on pipes 1 to be connected are arranged to face each other via a gasket 6, and bolts 4 inserted into twelve bolt holes 3 provided on each flange 2 are temporarily tightened with nuts 5. You. A bolt tensioner 7 is attached to each of two pairs (four in total) of bolts 4 on a diagonal line, and hydraulic pressure from a hydraulic device described later is supplied to each bolt tensioner 7 by a hydraulic pipe 8.

A strain gauge 9 is attached to the bolt tensioner 7 so that the tension applied to the bolt 4 can be measured. A gap measuring device (gap sensor) 10 is attached to a flange 2 (comparative flange) facing the flange 2 to which the bolt tensioner 7 is attached by an attachment jig 11. As the gap measuring device 10, for example, an air micrometer that can output an electric signal proportional to the measured value can be used. The mounting jig 11 is detachably attached to the flange 2 with a fixing tool such as a bolt or a magnet type fixing tool. FIG. 4 shows a known bolt tensioner 7, in which an insert 12 for screwing and connecting to the bolt 4 and an insert 12 are shown.
Load cell 13 and insert 12
And a load cell 13, a piston 14, an annular seal 15 disposed on the bottom surface of the piston 14, and a bridge 16 supporting the lower side of the load cell 13.

The insert 12 has a cylindrical main body 12b, and a flange-like head 12 is formed on the outer periphery of the end of the main body 12b.
a is provided. The outer peripheral surface of the head 12a is knurled to prevent slipping, a plurality of tool holes 12c for inserting a rotary tool are provided at equal intervals, and an inner screw for screwing into the bolt 4 is provided on the inner peripheral surface of the main body 12b. It is formed. The strain gauge 9 can be mounted between the head 12a and the piston 14. The load cell 13 has a cylindrical shape as a whole, and has an annular groove 13a on which a piston 14 is mounted.
Is provided, and a connector 13b for connecting the hydraulic pipe 8 is provided at an end of a hydraulic path communicating with the annular groove 13a. A flange is formed on the upper part of the cylindrical piston 14. The head 12a of the insert 12 is in contact with the upper surface of the flange, and the upper part of the load cell 13 is in contact with the lower surface of the flange. The bridge 16 formed in a cylindrical shape has a bottom surface in contact with the surface of the flange 2, and a plurality of openings 16 a for rotating the nut 5 are provided at predetermined intervals on a side portion.

FIG. 5 is an overall block diagram for controlling the bolt tensioner 7. The hydraulic device 17 includes a hydraulic supply device 18 including a hydraulic pump, a main valve 19, a return valve 20, a plurality of (four in this example) control valves 21, and a pipe connecting them. The hydraulic piping 8 to the bolt tensioner 7 is connected to the side. The control device 22 is composed of, for example, a personal computer, and includes a CPU (Central Processing Unit) 23 and a storage unit 24. CPU23
Is connected to an input device 25 such as a keyboard for inputting condition settings and arithmetic expressions, and an output device 26 such as a display or a printer. Further, measurement signals from each of the gap measuring devices 10 and the strain gauges 9 are input. Note that the CPU 23 and the external device are connected via an I / O (input / output unit), but are omitted in the drawing.

Next, a method for tightening the flange using the above-described device will be described. The following description describes a case where the process of simultaneously tightening the twelve bolts 4 every four bolts is repeated three times. [Preparatory work] (1) Insert two bolts 4 into the bolt holes 3 of the flange 2 and attach the nut 5, and insert the gasket 6 so as to be aligned with the center of the flange surface. (Insertion of Gasket) (2) Insert the remaining ten bolts 4 into the bolt holes 3 and attach the nuts 5. (Attaching the bolts) (3) Tighten the bolts 4 in a diagonal order with a wrench.
(4) The bolt tensioners 7 are arranged and attached at four positions, that is, up, down, left, and right (at 90 ° intervals) as shown in FIG. 1, and hydraulic piping 8 is connected to each. (5) The gap measuring device 10 is mounted with the mounting jig 11 as shown in FIG. 2 (and FIG. 3) in accordance with the mounting position of the bolt tensioner 7. (6) Connect the output cables of the gap measuring devices 10 and the strain gauges 9 to the control device 22 respectively.

[Advance Measurement] (1) The measured value of the gap between the flange surfaces of each gap measuring device 10 is input to the control device 22 and stored in the storage unit 24. (2) If necessary, the displacement of the circumferential surface of the opposed flange 2 (corresponding to the displacement of the center of the pipe) is measured with a tool such as a caliper, and the measured value is input from the input device 25 to the control device 22 and stored in the storage unit. 24. Further, if necessary, the number, material, and size of the bolts 4 are input to the control device 22 from the input unit 25 as management data, and are similarly stored in the storage unit 24. (3) The set value of the oil pressure in the oil pressure supply device 18 is input from the input device 25 to the control device 22 and stored in the storage unit 24.

[Bolt Tightening] (1) When a start signal is input from the input device 25 to the control device 22, first, the hydraulic pressure supply device 18 is started, the main valve 19 is opened, and the hydraulic pressure is supplied to each control valve 21. Hydraulic supply device 18
Is provided with a hydraulic pressure measuring device 18a, and a control signal is output from the control device 22 so that the measured pressure value matches the set value, and controls, for example, the discharge pressure of a hydraulic pump. (2) Next, the opening signals of the four control valves 21 are output from the control device 22, and the hydraulic pressure is supplied to the four bolt tensioners 7 via the respective control valves 21. Hydraulic pressure is supplied to the load cell 13 (FIG. 4) of the bolt tensioner 7, which causes the insert 12 to rise and extend the bolt 4. Then, the gap between the flange surfaces decreases, and when the decrease value reaches a preset value, a signal to close the control valve 21 is output from the control device 22 and the bolt tensioner 7
Stop supplying hydraulic pressure to Since this control is performed independently for each of the four bolt tensioners 7, each bolt 4 is uniformly extended. (3) Next, the loosened nuts 5 are tightened by hand for each bolt 4. (4) Next, when a switching command is input from the input device 25 to the control device 22, the control valve 22 closes the source valve 19, opens each control valve 21 and the return valve 20, and opens the hydraulic pipe 8. Becomes zero.

[Data Processing of Tightening Results, etc.] (1) The measured values of the gaps between the flange surfaces at the locations (four locations) where the bolt tensioners 7 are arranged are stored in the storage unit 24 of the control device 22. (2) If necessary, the deviation of the circumferential surface of the facing flange 2 is measured with a tool such as a caliper, and the measured deviation is input from the input device 25 to the control device 22 and stored in the storage unit 24. Further, the control unit 22 compares the value with the deviation of the circumferential surface stored in (2) of [Advance Measurement], and stores it in the storage unit 24 as management data.

[Switching of Tightening Bolts] (1) The four bolt tensioners 7 are respectively switched from the conventional bolts 4 to the bolts 4 which are rotated by, for example, 30 ° counterclockwise. (2) The mounting positions of the four gap measuring devices 10 are changed in accordance with the switching of the bolt tensioner 7. (3) The above-mentioned steps of [preliminary measurement], [bolt tightening] and [data processing of tightening result, etc.] are repeated for a new bolt 4.

[Final confirmation of the gap between the flange surfaces, etc.] (1) Using a skimmer gauge, the circumferential direction of the flange 2
The gap (45 ° pitch) is precisely measured, input from the input device 25 to the control device 22 and stored in the storage unit 24. (2) The storage data of (1) is printed out by the output device 26 and stored. Flange 2 stored as necessary
The comparison data of the deviation of the circumferential surface is printed out by the output device 26 and stored.

[0017]

As described above, according to the method for fastening a flange of the present invention, the tension applied to the bolt by the bolt tensioner is controlled so that the measured value of the gap between the flange surfaces becomes a preset value. Fastening can be performed efficiently and accurately. Further, since the bolts are tightened in a state where tension is applied, even if the temperature around the flange becomes high and the bolts elongate during operation, the bolts are not loosened and no additional tightening is required. In the above method, it is possible to tighten the nut by simultaneously applying tension to each bolt inserted into the bolt hole on the diagonal line of the flange,
By doing so, the tightening can be performed more accurately and quickly, and the working efficiency can be increased. Further, a flange tightening device of the present invention includes a bolt tensioner for applying tension to a bolt by hydraulic pressure, a control valve provided on a hydraulic pipe for supplying hydraulic pressure to the bolt tensioner, and a gap measurement for measuring a gap between flange surfaces. And a control device for controlling the control valve so that the gap between the flange surfaces by the gap measuring device is a preset value, which is preferably used to implement the above-described tightening method. Can be used.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a method for fastening a flange according to the present invention.

FIG. 2 is an enlarged view of a bolt and a bolt tensioner in FIG. 1;

FIG. 3 is a front view showing a relationship between a flange in FIG. 2 and a gap measuring device attached to the flange.

FIG. 4 is a specific structural view of a bolt tensioner 7;

FIG. 5 is an overall block diagram for controlling a bolt tensioner 7;

FIG. 6 is a front view showing a flange portion of the pipe.

FIG. 7 is a view showing a surface portion of the flange of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piping 2 Flange 3 Bolt hole 4 Bolt 5 Nut 6 Gasket 7 Bolt tensioner 8 Hydraulic piping 9 Strain gauge 10 Gap measuring instrument 11 Mounting jig 12 Insert 12a Head 12b Body 12c Tool hole 13 Load cell 13a Annular groove 13b Connector 14 Piston 15 Seal 16 Bridge 16a Opening 17 Hydraulic device 18 Hydraulic supply device 18a Oil pressure measuring device 19 Main valve 20 Return valve 21 Control valve 22 Control device 23 CPU 24 Storage unit 25 Input device 26 Output device

Claims (3)

[Claims] In a method of tightening a pair of opposed flanges with a plurality of bolts and nuts, the bolt is inserted into a bolt hole of the flange, and a tension is applied to the bolt by a bolt tensioner. Extend,
At that time, the gap between the flange surfaces is measured by the gap measuring device 10,
A method for tightening a flange, comprising controlling a tension applied to a bolt so that the value becomes a preset value, and attaching a nut to the bolt in this state. 2. The flange tightening according to claim 1, wherein a tension is simultaneously applied to each of the bolts 4 inserted in at least the diagonal bolt holes 3 of the flange 2 by a bolt tensioner 7 to attach the nut 5. Method. 3. An apparatus for tightening between a pair of opposed flanges 2 with a plurality of bolts 4 and nuts 5, a bolt tensioner 7 for applying tension to the bolt 4 by hydraulic pressure, and a hydraulic pipe 8 for supplying hydraulic pressure to the bolt tensioner 7. , A gap measuring device 10 for measuring the gap between the flange surfaces, and a control device for controlling the control valve 21 so that the gap between the flange surfaces by the gap measuring device 10 becomes a preset value. 22
And a flange tightening device.