JP2005337586A - Bolt cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bolt cooling device for cooling a bolt in a short time with high operability and working efficiency. <P>SOLUTION: The bolt cooling device comprises a heat pipe having a diameter smaller than that of a hole of the bolt and storing liquid refrigerant and a plurality of radiating fins provided at one end of the heat pipe. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel bolt cooling device for bolting a casing such as a steam turbine in a power plant.

  In periodic inspections of steam turbines installed at thermal power plants and nuclear power plants, when reassembling the steam turbine casing, the fastening bolts are heated to a specified temperature and tightened with a specified torque. There is work to cool. Incomplete tightening may cause steam leakage and hinder the operation of the steam turbine, and this work must be performed appropriately.

  The casing temperature when the steam turbine is operated is several hundred degrees Celsius, for example, about 200 degrees Celsius. Even if the bolt is tightened at room temperature, the bolt is stretched at a high temperature due to the difference in thermal expansion coefficient between the casing and the bolt, and a predetermined tightening torque However, the bolt is heated in advance, tightened with a predetermined torque and then cooled, and the next bolt is sequentially heated and tightened to cool. Although the casing also expands due to thermal expansion, since the expansion coefficient of the bolt is usually larger, a tightening operation for preventing loosening as described above is required.

  Also, a hole is installed in the bolt in the axial direction, and after a heating bar heater is inserted and a predetermined temperature is reached, or after a lapse of a considerable time, the bar heater is pulled out and tightened with a predetermined torque. Conventionally, it is carried out by an operation method in which the next bolt is similarly tightened in the same manner after being allowed to stand naturally for cooling or by forcibly blowing wind and lowering to a predetermined temperature.

  This type of bolt is, for example, a very large diameter of 150 mm and a length of 1 m, and is a work for fastening dozens of bolts. There was a problem that it took about 15 hours to move to tightening. Further, the method of forcibly blowing wind can shorten the time, but it still takes about 4 hours. In this type of power plant, a period and a time period when the demand for power is low is selected, the spare generator is used to cover the demand, and this operation is performed for the generator.

  FIG. 5 is a cross-sectional view showing a state in which the bolt is cooled to the flanges 5 and 6 of the steam turbine casing by the heated bolt 2 and then cooled using the bolt cooler described in Patent Document 1. As shown in FIG. 5, the upper casing flange 5 and the lower casing flange 6 are fastened by bolts 2, nuts 3 a and 3 b, and washers 4. Bolt 2 is provided with an axial hole 2a, and when heated, a heater is inserted, energized and heated, energized for a time corresponding to a predetermined temperature and 250 ° C., and then tightened with nuts 3a and 3b with a prescribed torque. . When this operation is completed, among the tens of bolts, adjacent bolts are similarly heated and tightened. After these tightening operations are completed, for example, for three bolts, the cooling operation is started. After lowering to a predetermined temperature or after a considerable time, after passing through a step of confirming whether the tightening torque can satisfy a specified value by dimensional measurement conversion of a predetermined portion, the next tightening operation is performed. The cooler 7 has a plurality of holes for blowing out cooling air in the lower cylindrical portion, is connected with a cooling air introduction hose 7a, and after the tightening operation is finished, the cylindrical portion is inserted into the bolt hole 2a. Cooling air is sent from the cooling device (not shown) to the inner wall surface of the hole 2a to cool it.

JP 2003-117739 A

  However, the bolt cooling device disclosed in Patent Document 1 requires devices such as a cooling compressor and a blower, and requires handling of a power cable and an air introduction hose, so that operability is low. In addition, shortening the working time is an important issue.

  An object of the present invention is to provide a bolt cooling device that has high operability and work efficiency and can cool bolts in a short time.

  The present invention includes a heat pipe having a diameter smaller than a hole provided in a bolt and having a liquid refrigerant therein, and a plurality of radiating fins provided at one end of the heat pipe. In the bolt cooling system.

  Further, the present invention has a flange portion having a diameter larger than the diameter of the hole on the heat radiating fin side of the heat pipe, and the heat radiating fin is composed of a plurality of plates and is formed radially on the circumferential surface of the heat pipe. It is preferable that

  Furthermore, the present invention has a radiation fin mounting member having an outer diameter larger than the outer diameter of the heat pipe at the end of the heat pipe, and the plurality of plates are joined to the radiation fin mounting member. In addition, it is preferable that a plurality of metal wires are provided in the longitudinal direction along the axial direction inside the heat pipe.

  Furthermore, it is preferable that the heat pipe, the radiation fin, the radiation fin mounting member, and the metal wire are at least one of aluminum and copper, and the refrigerant is water, an organic refrigerant or the like.

  In the present invention, the member to be fastened is fastened with a bolt having a hole in the axial direction, a heater is inserted into the hole and energized and heated, and then the nut is tightened with a specified torque, and then the adjacent bolt is heated and tightened. After completing a plurality of tightening operations, a heat pipe having a smaller diameter in the hole and having a liquid refrigerant inside is inserted into the hole, and a plurality of heat dissipations provided at one end of the heat pipe A bolt cooling method is characterized in that the bolt is cooled through a fin.

  After cooling the bolt, after passing through a step of confirming whether the tightening torque can satisfy a specified value by dimensional measurement conversion of a predetermined part, the next tightening operation is performed, and the fastened member is connected to the upper casing flange. It is characterized by fastening with the lower casing flange.

  According to the present invention, it is possible to provide a bolt cooling device that has high operability and work efficiency and can cool bolts in a short time.

  FIG. 1 is a perspective view showing a bolt cooling device of the present invention. The bolt cooling device 1 includes a radiation fin 1a, a flange portion 1b, and a heat pipe 1c. Water is sealed inside the heat pipe 1c, and plays the role of conducting the heat of the medium touching the outside of the case to the radiation fins 1a.

  FIG. 2 is a sectional view showing a state in which the bolt cooling device of the present invention is used, and the bolt cooling device is a front view. As shown in FIG. 2, the upper casing flange 5 and the lower casing flange 6 of the steam turbine are fastened by bolts 2, nuts 3 a and 3 b, and washers 4. The bolt 2 is provided with an axial through hole 2a. When the bolt 2 is heated, a rod heater is inserted into the through hole 2a, energized for a time corresponding to a predetermined temperature of 200 ° C. by energization, and then a nut with a specified torque. 3a and 3b are manually tightened with a spanner. When this heating operation is completed, heating and tightening operations are performed in the same manner for every two adjacent bolts 2 out of several tens of bolts 2. After these tightening operations are completed, for example, three bolts, the cooling operation is started. After the temperature is lowered to a predetermined temperature by cooling or after a lapse of a considerable time, after passing through a step of confirming whether the tightening torque can satisfy the specified value by dimensional measurement conversion of the predetermined portion, the next tightening operation is performed in the same manner as described above. The next tightening operation is performed symmetrically with respect to the plane of the casing.

  FIG. 3 is a cross-sectional view of the bolt cooling device according to the present invention. As shown in the figure, the bolt cooling device includes a heat radiating fin 1a, a flange portion 1b, a heat pipe 1c, a heat radiating fin mounting member 8, a metal wire 9 and a refrigerant 10 provided in the heat pipe 1c, and a heat pipe. The heated bolt 2 is cooled by inserting 1c into a through hole 2a provided in the bolt 2.

  The plurality of heat dissipating fins 1a installed at the upper part are made of a light plate material having good heat conduction such as aluminum, and are formed radially at one end of the heat pipe 1c. The plate material may be disk-shaped and has a hole corresponding to the diameter of the radiating fin mounting member 8, and can be formed by shrink fitting, welding, or the like through the hole.

  The radiating fin mounting member 8 is a cylindrical solid material, has a hole corresponding to the diameter of the heat pipe 1c, can be formed by shrink fitting into the heat pipe 1c through the hole, welding or the like. The heat dissipating fin mounting member 8 accumulates heat from the heat pipe 1c sufficiently and dissipates it through the heat dissipating fin 1a, so that its heat capacity is increased so that the heat dissipating fin 1a has a diameter 5 to 10 larger than that. It has a diameter that is twice as large as its radial length. The axial length is preferably 15 to 35% of the insertion length of the heat pipe 1c.

  The flange portion 1b also has a hole corresponding to the diameter of the heat pipe 1c, and can be formed by shrink fitting, welding, or the like through the hole. A large number of aluminum wires 9 are inserted into the heat pipe 1c, and further, a refrigerant 10 is filled therein.

  In the above cooling operation, the heated bolt 2 is fastened with the nuts 3a and 3b via the washer 4, and the upper casing flange 5 and the lower casing flange 6 are fastened, and then the heat pipe of the bolt cooling device 1 is used. When 1c is inserted into the through hole 2a, the flange portion 1b comes into contact with the upper end surface of the bolt 2 and stops. In this state, the heat of the bolt 2, which has become high over time, is transferred to the water in the heat pipe 1c, and the warmed water becomes steam and rises toward the radiation fins 1a. The water vapor is released into the atmosphere through 1a, and the water vapor is returned to the water again by the discharge, and gathers in the lower part of the heat pipe 1c through the metal wire 9, and the bolt 2 is cooled by repeating the circulation. The main specifications of this embodiment are as follows.

Bolt 2: diameter 150mm, length 1m,
Heat pipe: Aluminum material, outer diameter 30mm, inner diameter 20mm, length 1m
Radiation fin 1a: Aluminum material, thickness 2mm, width 50mm, length 250mm, 50 sheets Radiation fin mounting member 8: Aluminum material, outer diameter 550mm, inner diameter 20.2mm,
Width 250 mm, shrink-fitting joining Metal wire: Aluminum material, diameter 1 mm, length 800 mm, 250 pieces FIG. The initial heating temperature of the bolt 2 is about 200 ° C., and the temperature is lowered to about room temperature in 90 minutes. The natural cooling required about 15 hours and the forced air cooling required about 4 hours, but the bolt cooling device of this example could reduce the time.

  As described above, according to the present embodiment, the compressor and the cooling air introduction hose which have been necessary in the past are not required, the operability and work efficiency are high enough to be inserted into the hole of the bolt, and the bolt can be cooled in a short time. A bolt cooling device can be provided.

It is a perspective view of the bolt cooling device concerning the present invention. It is sectional drawing which inserted the bolt cooling device which concerns on this invention in the bolt fastening part. It is sectional drawing which inserted the bolt cooling device which concerns on this invention in the bolt fastening part. It is a diagram which shows the relationship between the temperature of the volt | bolt of a bolt fastening part, and time with the volt | bolt cooling device which concerns on this invention. It is sectional drawing which inserted the bolt cooler of the prior art example in the bolt fastening part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cooling device, 1a ... Radiation fin, 1b ... Flange part, 1c ... Heat pipe, 2 ... Bolt, 2a ... Hole, 3a, 3b ... Nut, 4 ... Washer, 5 ... Upper casing flange, 6 ... Lower casing flange , 7 ... cooler, 8 ... radiating fin mounting member, 9 ... metal wire, 10 ... refrigerant.

Claims (4)

  A bolt cooling device comprising: a heat pipe having a diameter smaller than a hole provided in a bolt and having a liquid refrigerant therein; and a plurality of heat dissipating fins provided at one end of the heat pipe.   The bolt cooling device according to claim 1, further comprising a flange portion having a diameter larger than a diameter of the hole on the heat radiating fin side of the heat pipe.   The bolt cooling device according to claim 1 or 2, wherein the heat dissipating fins are formed of a plurality of plates and are formed radially on a circumferential surface of the heat pipe.   In Claim 3, it has a radiating fin attachment member which has an outer diameter larger than the outer diameter of the heat pipe in the end of the heat pipe, and the plurality of plates are joined to the radiating fin attachment member. Bolt cooling device characterized.

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