JPH06101417A - Fastening device - Google Patents

Abstract

PURPOSE:To demount nuts and a bolt early with ease in a high temperature condition after stipping a turbine by forming a tapered port on a center portion of the bolt, inserting a tapered bar into the tapered port, and thereby suppressing contraction of the bolt at the cooling time. CONSTITUTION:A bolt 9 is inserted into a bolt hole 2 of an outer casing 1. A tapered center hole 10 is formed on an inner portion of the bolt 9. Multiple nuts 12 are provided on an upper half part of the outer casing 1. After stopping a turbine, a tapered extention bar 11 of a low temperature is inserted into the center hole 10 of the bolt 9 immediately, and fixed by a stopper 13. The bolt 9 and a flange 14 of the outer casing 1 is going to contract accompanied with cooling, while the tapered extention bar 11 is heated and expanded by means of the bolt 9, to the contotary. The contraction of the bolt 9 is suppressed, and the flange 14 alone is contracted, accordingly. The multiple nuts 12 is thus demounted one by one from an upper side with a small torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flange bolt tightening device.

[0002]

2. Description of the Related Art In a turbo machine with a high working fluid inlet temperature, even if the machine stops, the metal surface of the main body is several hundred degrees, and it does not cool suddenly. It is impossible to disassemble and inspect the interior or replace parts. For example, in the case of a steam turbine, it takes about 5 to 6 days until the turbine can be disassembled after the turbine is stopped, which is one of the causes of the decrease in the turbine operating rate at the power plant. FIG. 3 shows a flange bolt structure of a horizontal portion of an external casing of a steam turbine which has been conventionally used.

Usually, since the bolts 3 and the nuts 4 and 5 are large in size, they cannot be tightened by rotating the nuts. Therefore, the bolt heater 7 is put in the hole 8 at the center of the bolt to heat the bolt, and thermal expansion causes the entire length of the bolt to be increased. With the nut extended, lightly tighten the nuts 4 and 5 with a wrench or the like, and tighten with the shrinkage allowance during cooling.

FIG. 4 is a sectional view showing a mounting state of bolts and nuts. A bolt hole 2 is provided in a horizontal flange portion of the turbine outer casing 1 into which a bolt 3 is inserted, and is tightened by upper and lower nuts 4 and 5.

[0005]

[Problems to be Solved by the Invention] When the turbine is stopped,
The temperature around the flange is about 300 to 500 ° C, and the tightening force of the nuts 4 and 5 is large, so it is difficult to easily rotate and remove. Therefore, after the turbine is stopped, the case opening work cannot be started immediately.

The object of the present invention is to enable the bolts and nuts of the casing horizontal flange portion to be easily disassembled even in a high temperature state after the turbine is stopped, so that the internal inspection of the turbine and the replacement of parts can be performed at an early stage. (EN) Provided is a flange bolt tightening device which is made possible.

[0007]

In the tightening device of the present invention, a taper-shaped hole is provided in the center of the bolt, and a taper-shaped rod is inserted into the hole to prevent the bolt from shrinking when the joint bolt is cooled. It is a tightening device for the turbo machine flange that suppresses it.

[0008]

In the flange bolt of the present invention, a taper type extension rod that suppresses bolt contraction is inserted in the center of the bolt, and a multiple type nut is further adopted to easily remove the bolt nut after stopping the turbine. Is made possible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIG. The present invention will be described by giving the same reference numerals to the same configurations as those of the above-mentioned conventional embodiment.

In FIG. 1, a bolt 9 is inserted into the bolt hole 2 of the outer casing 1. There is a tape at the center of this bolt 9.
The center hole 10 of the par is processed. The nuts in the upper half of the external casing are mounted with multiple nuts 12 formed by stacking a plurality of plates and threading them.

Immediately after the turbine stops, the central hole of the bolt 9
Insert the low temperature taper extension rod 11 into 10 and press and fix it with the stopper 13. The bolt 9 and the flange 14 gradually cool down and try to shrink, but the taper extension rod 11 is heated by the bolt 9 and begins to extend. Therefore, the contraction of the bolt is suppressed and only the flange 14 is contracted. In this state, multiple nuts
It is possible to remove the nuts one by one from the upper surface of 12 with a small rotating torque. Taper extension rod 11 is a multi-type nut
It is installed for the purpose of protecting the threads of each nut from excessive force when disassembling 12.

FIG. 2 shows another embodiment of the present invention. Target
Immediately after stopping the bottle, an extension rod 16 made of austenite or a material having a high coefficient of thermal expansion is inserted into the center hole 20 of the bolt 15 at a low temperature, and the extension rod 16 is stopped by the pin 18. Pin 18 is cover 19
Fix with. With the passage of time, the extension rod 16 is heated from the bolt 15 and extends, so that the bolt 15 also begins to extend. Therefore, the nuts 17 and 5 are automatically loosened and can be easily disassembled.

[0013]

As described above, according to the present invention, by installing the extension rod immediately after the stopping of the turbine, the bolts and nuts can be easily disassembled, and the external casing can be released early.
It is possible to inspect the turbine and replace parts.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a perspective view of a conventional example.

FIG. 4 is a sectional view of a conventional example.

[Explanation of symbols]

 1 ... External casing 2 ... Bolt hole 3,9,15 ... Bolt 4,5, Nut 6 ... Spanner 7 ... Bolt heater 8 ... Heating hole 10,20 ... Center hole 11 ... Taper extension rod 12, 17 ... Multiple Nut 13 ... Stopper 14 ... Flange 16 ... Extension Rod 18 ... Pin 19 ... Cover

Claims (3)

[Claims] Claim: 1. A taper-shaped hole is provided in the center of a bolt, and a taper-shaped rod is inserted into the hole to tighten the turbomachine flange portion to prevent the bolt from shrinking when the joint bolt is cooled. apparatus. 2. The tightening device according to claim 1, wherein a multiple nut formed by stacking a plurality of plates and screwing them is attached to a flange portion to reduce a rotation torque when removing the nut. 3. The tightening device according to claim 2, wherein an austenitic material or an extension rod having a high coefficient of thermal expansion is inserted into the hole at the center of the bolt, and the nut is automatically loosened by the thermal expansion of the extension rod.