JP4859533B2 - Repair method for existing joints - Google Patents

Description

  The present invention relates to a method for repairing an existing joint, and in particular, a small-diameter pipe is inserted into a large-diameter pipe, and a filling member is provided in an annular gap formed between the inner peripheral surface of the large-diameter pipe and the outer peripheral surface of the small-diameter pipe. The filling member is a water-stopping packing formed of an elastic member and a cotton packing braided into a square cross section and grease-finished in order from the back side toward the opening side of the large-diameter pipe. The present invention relates to a repair method for an existing joint in which the existing filling member is taken out from an existing joint connected by pressing and fixing the filling member from the opening side of the large-diameter pipe with a pressing member, and a new filling member is disposed.

  FIG. 5 is a schematic diagram showing an arrangement state of the hydraulic iron pipes arranged in the power plant. A hydraulic iron pipe 2 is disposed in a water channel connected to the generator of the hydroelectric power plant. The hydraulic iron pipe 2 forming such a water channel is disposed on the slope 1 via a base (not shown). In FIG. 5, reference numeral 3 denotes a work table provided on the slope 1, and an operator performs work such as maintenance and inspection of the hydraulic iron pipe 2 on the work table 3.

  In this example, as for the hydraulic iron pipe 2, many iron pipes 10 (for example, inner diameter D: about 2000 mm) which are small diameter pipes having a predetermined length dimension (for example, several tens of meters) are arranged, and butt ends of the respective iron pipes 10 A cylindrical sleeve member 20, which is a large-diameter pipe covering the end portion, is disposed at the end, and a filling member 40 is disposed in an annular gap portion 31 formed between the outer periphery of the sleeve member 20 and the inner periphery of the iron tube 10. The joint portion 30 is configured in two places.

  FIG. 6 is a cross-sectional view showing a connection state between the iron pipe and the sleeve member, and FIG. 7 is a cross-sectional view showing a joint portion of the existing hydraulic iron pipe. In this example, one sleeve member 20 is provided with two joint portions 30 in total between two iron pipes 10, so that the two iron pipes 10 are connected by one sleeve member 20. It has become. In the joint portion 30, an annular gap portion 31 is formed between the inner peripheral surface 20 a of the sleeve member 20 and the outer peripheral surface 10 a of the iron pipe 10, and the annular gap portion 31 is filled with a filling member 40 that makes water tight. . The filling member 40 is disposed in the annular gap portion 31 and is press-fitted into the annular gap portion 31 with a fastener 50 that is a pressing member.

  An annular stopper 21, which is a stepped portion that contacts and positions the filling member 40, is welded and fixed to the inner peripheral surface 20 a of the sleeve member 20, and the fastener 50 is attached to the outer peripheral surface 20 b over the entire circumference. A fastener engaging portion 22 that is a fixing member for attachment is fixed by welding (reference numeral 26 in FIG. 7).

  The fastener engaging part 22 is an annular L-shaped steel material formed from a bottom wall part 23 attached to the outer peripheral surface 20 b of the sleeve member 20 and a flange part 24 extending outward from the bottom wall part 23. And is attached to the outer peripheral surface 20 b of the sleeve member 20. A predetermined number (for example, 48) of bolt insertion holes 25 are opened in the flange portion 24 at an equiangular interval (360 ° / 48 = 7.5 °).

  In this example, as shown in FIG. 5, the filling member 40 is made of cotton which is braided into two water-stopping packings 41 and 42 and a square cross section and grease-finished toward the opening side of the sleeve member 20 from the back side. It is arranged in the order of grease cotton 43 which is packing.

  And this filling member 40 is compressed and arrange | positioned from the opening side of the sleeve member 20 when the fastener 50 is press-fitted in the annular clearance 31.

  The fastener 50 is an annular member arranged around the iron pipe 10 so as to be movable in the axial direction. The fastener 50 is formed by annularly forming an L-shaped steel material formed from a peripheral wall portion 51 disposed on the outer peripheral surface 10a side and a flange portion 52 extending outward from the peripheral wall portion 51. It has been done. The same number of bolt insertion holes 54 (48 in this example) as the above-described fastener locking portions 22 are formed in the flange portion 52 at equal angles (360 ° / 48 = 7.5 °). The bolt insertion hole 54 is opened at a position where the bolt 55 can be inserted into the bolt insertion hole 54 and the bolt insertion hole 25 of the fastener locking portion 22 and tightened with the nut 56.

  The joint portion 30 according to this example can absorb the expansion and contraction of the iron pipe 10 due to the environmental temperature and connect the iron pipe 10 and the sleeve member 20 in a watertight state.

  By the way, in such a joint part of an iron pipe, the relative position between the iron pipe 10 and the sleeve member 20 in the joint part 30 may be shifted due to a secular change due to an environmental temperature difference or the like. As a result, the water tightness of the joint portion 30 is lowered, and water leakage may occur. In particular, when the iron pipe 10 and the sleeve member 20 are displaced in the direction perpendicular to the axis, the size of each position of the annular gap 31 changes, and the filling member 40 filled in the annular gap 31 and the outer peripheral surface 10a of the iron pipe 10 are changed. A gap is generated between the inner peripheral surfaces 20a of the sleeve members 20, and water leakage occurs. In such a case, if water leakage occurs even in a small amount, the grease in the grease cotton will come off together with the water leakage from the grease cotton, and the water stoppage will decrease, and the amount of water leakage will increase. Further, the grease cotton may be pushed out from the gap between the fastener 50 and the sleeve member 20 of the joint portion.

  The joint portion in such a state needs to be repaired. In the repair work, the inside of the hydraulic iron pipe 2 is drained, the fastener 50 is removed from the joint portion 30, and between the iron pipe 10 and the sleeve member 20. The filling member 40 is taken out, a new filling member is arranged in the annular gap portion 31, and the fastener 50 is attached.

  However, simply disposing the same filling member 40 as that of the existing joint portion 30 often causes water leakage again. That is, the dimension of the annular gap 31 between the iron pipe 10 and the sleeve member 20 into which the filling member 40 is press-fitted becomes various values due to secular change, and is simply the same water-stopping packing 41, 42 as the existing filling member 40, Even if grease cotton 43 is used, good water stoppage cannot be performed.

  Then, this invention aims at providing the repair method of the existing joint which can repair the existing joint by which the dimension of the annular clearance part between an iron pipe and a sleeve member changed by secular change with favorable water stop performance. To do.

In the present invention, the means for solving the above-mentioned invention is that the small-diameter pipe is inserted into the large-diameter pipe, and the annular gap formed between the inner peripheral surface of the large-diameter pipe and the outer peripheral surface of the small-diameter pipe, A filling member is arranged, and the filling member is arranged in order from the back side toward the opening side of the large-diameter pipe, a water-stopping packing formed of an elastic member, and a cotton packing braided into a square cross section and grease-finished. In the repair method of the existing joint, the existing filling member is taken out from the existing joint connected by pressing and fixing the filling member from the opening side of the large-diameter pipe with the pressing member, and a new filling member is arranged.
After placing a new inner water-proof packing from the back side as the new filling member, and a cotton packing braided into a new square cross section and grease-finished, a new outer water-proof packing formed of an elastic member is arranged. The existing joint repair method is characterized by attaching the pressing member.

  According to the present invention, it is possible to prevent leakage of water from between the large-diameter pipe and the small-diameter pipe by the newly provided outer water-stopping packing, and to prevent the elution of grease accompanying water leakage from the cotton packing. It is possible to maintain the waterproofness of the cotton packing, and to improve the water tightness of the joint.

  Hereinafter, the repair method of the existing joint which concerns on embodiment of this invention is demonstrated based on FIG. 1 thru | or FIG.

  FIG. 1 is a cross-sectional view showing a state of a joint portion after construction of an existing joint repair method according to this example, and FIG. 2 is a cross-sectional view showing a state of the joint portion from which a filling member is removed.

  In this example, the iron pipe 10, the sleeve member 20, the fastener 50, the bolt 55, and the nut 56 constituting the new joint part 70 are the same as those shown in the conventional example. That is, the sleeve member 20 is fitted into the iron pipe 10. In the repair method for the existing joint according to this example, since the iron pipe 10 is kept in the state of being disposed on the slope 1, the positional relationship between the iron pipe 10 and the sleeve member 20 does not change. Moreover, the stopper 21 and the fastener locking part 22 remain attached to the sleeve member 20, and the fastener 50 is movably fitted in the iron pipe 10. The fastener 50, the bolt 55, and the nut 56 can be replaced with new ones depending on the state of deterioration.

  In the repair method for the existing joint according to this example, first, the filling member 40 is taken out from the annular gap portion 31 of the existing joint portion 30. This is to remove the filling member 40 from the state shown in FIG. 7, and is the same as the method performed in the conventional repair. When the filling member 40 is taken out, nothing is placed in the annular gap 31 between the iron pipe 10 and the sleeve member 20 as shown in FIG. In this example, two new inner waterproof packings 61 and 62, new cotton packing grease cotton 63, and a newly added outer water blocking packing 64 are disposed in the annular gap 31 as a filling member 60 for repair. The fastener 50 is disposed. In this example, the dimension C of the annular gap 31 is measured in order to determine the dimensions of the inner waterproof packings 61 and 62 and the outer water blocking packing 64.

  FIG. 3 is a schematic diagram showing measurement points of dimensions. In this example, as shown in FIG. 3, the dimension C is measured at several places, for example, eight places on the annular gap portion 31 on the edge portion side of the sleeve member 20. In this example, C1: sky, C2: right sky, C3: right, C4: right ground, C5: ground, C6: left ground, C7: left, C8: left sky are measured as eight dimensions C1 to C8. To do. Note that the number of measurement points is not limited to eight, and may be changed as necessary. This dimension is usually performed using a measure, a ruler for dimension measurement, and the like. That is, the major point 0 is set on the outer peripheral surface 10 a of the iron pipe 10, and the dimension to the inner peripheral surface 20 a of the sleeve member 20 is measured.

  FIG. 4 is a table showing an example of dimension determination. In this example, the attachment dimension W (see FIG. 1) of the fastener engaging part 22 and the fastener 50 before and after repair and the inner diameter D of the iron pipe 10 are also measured.

  Next, an intermediate value of the measured dimension values C1 to C8 is selected to determine the thickness dimension, that is, the diameter dimension, of the inner waterproof packings 61 and 62 and the outer waterproof packing 64.

  No. In the joint 1, a packing thickness of 19 mm is selected for these values of C1 to C8. This value is selected as a value slightly larger than the minimum dimension value C8: 18.0 mm. The waterproof packing of this size is a size that can be pushed into the annular gap portion 31 and a size that sufficiently exhibits water-stopping properties has been selected by pushing the fastener 50 into the maximum size of 22.0 mm. About the selection of the dimension of this waterproof packing, it confirms by the past construction example and experiment about various cases, and the dimension is selected.

  For the same reason, no. In the joint of No. 2, a packing thickness of 22 mm is selected for the values of C1 to C8.

  In this example, as the waterproof packing, both ends of a cylindrical member made of synthetic rubber having a selected diameter and capable of being tightly wound around the iron tube 10 having a predetermined diameter are bonded and arranged in an annular shape. The shape of the bonding surface and the adhesive need to prevent water leakage from the bonded portion.

  In this way, the inner waterproof packings 61 and 62 having the selected dimensions are wound around the iron pipe 10 and both ends thereof are adhered and disposed, and the inner waterproof packings 61 and 62 are pushed into the annular gap 31 until they contact the stopper 21.

  Next, the grease cotton 63 is wound around the iron pipe 10 with a predetermined number of turns (four turns in No. 1 and two turns in No. 2), and is pushed into the annular gap 31 until it contacts the inner waterproof packing 62. The inner waterproof packings 61 and 62 and the grease cotton 63 are inserted in the same manner as a conventional repair method for existing joints. Then, the outer water-stop packing 64 is wound around the iron pipe 10 and both ends thereof are adhered and arranged, and pushed in until the grease cotton 63 is contacted in the annular gap 31.

  Then, the peripheral wall 51 of the fastener 50 is pushed into the annular gap 31 so as to contact the outer water-stop packing 64, and the bolt 55 is inserted into the bolt insertion hole 25 of the fastener locking portion 22 and the bolt insertion hole 54 of the fastener 50. Thread and tighten using nut 56. In this example, 48 bolts 55 and nuts 56 are tightened, tightening is performed until the mounting dimension W of the clasp locking portion 22 and the clasp 50 reaches a predetermined value, and further incremental tightening is performed diagonally. To do. Thereby, repair of the existing joint which concerns on this example is complete | finished.

  As described above, according to the repair method for an existing joint according to the present embodiment, the dimensions of the joint part to be actually repaired are measured, and the outer water-stop packing and the inner water-stop gasket having the optimum dimensions for the joint part are measured. In addition to preventing leakage of water between the large-diameter tube and small-diameter tube by packing, it is possible to prevent grease from being eluted due to water leakage from the grease cotton, and to maintain the water-stopping property of the grease cotton. It has the effect that the water tightness of a joint part can be improved.

It is sectional drawing which shows the state of the joint part after construction of the repair method of the existing joint which concerns on embodiment. It is sectional drawing which shows the state of the joint part which removed the filling member. It is the schematic which shows the dimension measurement location of the cyclic | annular clearance gap part used as repair object which concerns on embodiment. It is a table | surface which shows the dimension in each dimension location shown in FIG. 3, and the dimension of the determined waterproof packing. It is a schematic diagram which shows the arrangement | positioning state of the hydraulic iron pipe arrange | positioned at a power station. It is sectional drawing which shows the connection state of an iron pipe and a sleeve member. It is sectional drawing which shows the joint part of the existing hydraulic iron pipe.

Explanation of symbols

10 Iron pipe (small diameter pipe)
10a Outer peripheral surface 20 Sleeve member (large diameter pipe)
20a Inner peripheral surface 31 Annular gap 40 Filling member 41, 42 Water-stop packing 43 Grease cotton (cotton packing)
50 Fastener (pressing member)
60 Filling member (new filling member)
61,62 Inner waterproof packing (new inner waterproof packing)
63 grease cotton (new cotton packing)
64 Outside water seal

Claims (6)

A small-diameter pipe is inserted into the large-diameter pipe, and a filling member is disposed in an annular gap formed between the inner peripheral surface of the large-diameter pipe and the outer peripheral surface of the small-diameter pipe, and the filling member has a large diameter from the back side. A water-stopping packing formed of an elastic member and a cotton packing that is braided into a square cross section and grease-finished are arranged in this order toward the opening side of the tube, and the filling member is placed on the large-diameter tube with a pressing member. In the repair method of the existing joint, taking out the existing filling member from the existing joint that is pressed and fixed from the opening side, and arranging a new filling member,
After placing a new inner water-proof packing from the back side as the new filling member, and a cotton packing braided into a new square cross section and grease-finished, a new outer water-proof packing formed of an elastic member is arranged. A method for repairing an existing joint, wherein the pressing member is attached. 2. The repair of an existing joint according to claim 1, wherein the inner water-stop packing and the outer water-stop packing are formed by adhering both ends of an elastic cylindrical member having a predetermined length and are attached to the outer periphery of the small-diameter pipe. Method. The method for repairing an existing joint according to claim 1 or 2, wherein the cotton packing is formed by winding a long cotton packing base around an existing iron pipe. The inner periphery of the large diameter tube of the existing, the existing joint according to any one of claims 1 to 3, characterized in that to form a stepped portion in contact with the inner waterproofing packing of the filling member Repair method. The fixing method for an existing joint according to any one of claims 1 to 4 , wherein a fixing member for fixing the pressing member is formed on the existing large-diameter pipe. The small diameter tube is penstocks, the larger diameter tube is according to any one of claims 1 to 5, characterized in that a sleeve member disposed on the butt end of the penstock to be connected in two Repair method for existing joints.

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