JP2008032220A - Method of manufacturing fire resistant two-layer pipe joint with thermally expansive joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mount an annular thermally expansive joint on the end face of the outer layer of a fire resistant two-layer pipe joint while preventing the fall-off and deformation. <P>SOLUTION: This method of manufacturing the fire resistant two-layer joint with the thermally expansive joint attached to the end face of the outer layer comprises fitting to the end of a synthetic resin pipe joint 5, the annular thermally expansive joint 3 which has a width almost the same as the thickness of the outer layer 6 of mortar formed on the outer periphery with injection molding, setting it in a heated injection mold 3, and forming the outer layer 6 abutting on the thermally expansive joint with the injected mortar and then removing it from the mold to harden the mortar. Part of the injection mold contacting the thermally expansive joint is in a non-heated condition. A plurality of recessed holes or recessed grooves are formed in the reverse of the joint, a see-through hole is formed passing through the surface to the reverse, a cutout see-through hole is formed in the peripheral edge of the joint, or a mortar entry space 16 is formed with an annular hole of the joint as a tapered hole. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat-expandable jointed refractory double-layer pipe with a ring-shaped heat-expandable joint attached to a connection end of a fire-resistant double-layer pipe joint having a structure in which a synthetic resin pipe joint is covered with an outer layer of mortar. The present invention relates to a method for manufacturing a joint.

  A fire-resistant double-layer pipe with a synthetic resin pipe covered with a mortar pipe has been conventionally known. As a joint for connecting this fire-resistant double-layer pipe, a synthetic resin pipe joint is covered with an outer layer of mortar by injection molding. Refractory two-layer pipe joints having the following are also known. The reason why fire-resistant double-layer pipes and fire-resistant double-layer pipe joints are used is that the inner pipe is a synthetic resin pipe, so that drainage can flow smoothly, and the mortar coating covering the outer surface is the inner pipe due to the heat of the fire. This is because it has the advantage of preventing fire spread and high safety. As seen in Patent Document 1, the connection between such a fire-resistant double-layer pipe and a fire-resistant double-layer pipe joint is made of a graphite-based material whose volume expands to several to ten times when heat such as fire is applied. By interposing a thermally expansible joint, the heat of the fire is prevented from affecting the internal synthetic resin pipes and pipe joints by closing the gaps of the connecting portions.

  The pipe connection work is performed by inserting the pipe end of the refractory double-layer pipe into the pipe connection end of the refractory double-layer pipe joint and joining them together with an adhesive. It is necessary to pay attention so that the annular thermal expansion joint set at the end of the pipe does not fall off, and the work is relatively troublesome. If the setting is forgotten, the gap in the connection is closed with a paste-like wet joint. Although construction is underway, this has the inconvenience of losing aesthetics and cumbersome work.

In order to eliminate such inconvenience, as shown in Patent Document 2, an annular thermally expandable joint is attached to the end face of the outer layer of the mortar of the fireproof two-layer pipe joint with an adhesive, or it is found in Patent Document 3. Thus, it is considered to form a recess in the end face of the outer layer of the mortar of the fireproof two-layer pipe joint and fit an annular thermally expandable joint there. Furthermore, the applicant has proposed that a thermally expansible joint is arranged in a mold for forming an outer layer of a fire-resistant two-layer pipe joint, and the joint is attached to the end face simultaneously with the formation of the outer layer (Patent Document 1). ). Note that the reason why the heat-expandable joint is not attached to the fire-resistant double-layer pipe even if it is attached to the fire-resistant double-layer pipe joint is that the fire-resistant double-layer pipe is often cut to adjust the length during piping construction. This is because it is not practical to attach a thermally expandable joint to the end portion of the fireproof double-layer pipe because it increases waste.
JP 2003-161392 A Japanese Patent Laid-Open No. 2002-228054 Japanese Patent Laid-Open No. 2002-3280

  When attaching an annular thermally expandable joint to a fireproof two-layer pipe joint with an adhesive as in Patent Document 2, the inconvenience of forgetting to set the joint is eliminated, but adhesive application work and joint application work In general, since there are many types of pipe joints such as elbow type and branch type, it is difficult to attach by an automatic machine and it is a work that relies on manpower, which is not preferable because it takes time and increases costs. In addition, as in Patent Document 3, in the case where the thermally expansible joint is accommodated in the recess at the connection end of the fireproof two-layer pipe joint, the mortar around the recess is not cracked during mortar curing or transportation because the mortar around the joint is brittle The thickness of the mortar must be increased to a certain extent, resulting in the inconvenience that the outer layer is increased in weight, making construction and transportation inconvenient, and the thermally expandable joints lurk in the recesses. There is a drawback that it is difficult to check visually from the outside. On the other hand, as in Patent Document 1, a thermally expandable joint having a width substantially equal to the thickness of the mortar outer layer is provided in the injection mold, and the joint is joined to the end face simultaneously with the formation of the mortar outer layer of the fireproof two-layer pipe joint. This eliminates the need to paste the joints, and the thickness of the joints appears to be striped from the outside, making it easier to check the joint setting, but the mold prevents mortar from adhering to the inner surface. The actual product is heated to 60 to 90 ° C., so that the joint is deformed as if the joint is twisted or waved by the heat of the mold, and the outer surface of the outer layer is deformed due to the deformation. As a result, the joints were loosened or protruded, and the joints dropped out during transportation and construction of the product. The time for which the joints are in contact with the mold is only about 5 seconds in a standard product, but the actual condition is that the joint is still deformed.

  In the present invention, an annular thermally expandable joint having substantially the same width as the outer layer of the mortar is fixed to the pipe connection end portion with a sufficient adhesive force that is difficult to drop off, and it is easy to check whether there is a joint after construction. It is an object to easily manufacture a simple fireproof two-layer pipe joint.

  In the present invention, in order to solve the above problems, an annular thermally expandable joint having a width substantially equal to the thickness of the outer layer is fitted to the outer periphery of the end portion of the synthetic resin pipe joint on which the outer layer of mortar is formed. Then, this is set in a heated injection mold, and after the outer layer contacting the thermally expandable joint is formed around the synthetic resin pipe joint by the injected mortar, it is taken out from the mold. In the method for producing a fire-resistant two-layer pipe joint in which a thermally expandable joint is adhered to the end face of the outer layer by curing mortar, at least a part of the portion where the injection mold comes into contact with the thermally expandable joint A heating state was set.

  The injected mortar flows between the inner wall of the heated injection mold and the outer surface of the synthetic resin pipe joint, and is injected until it contacts the entire surface of the thermally expandable joint located at the end of the joint. However, since a part of the mold in contact with the joint is in an unheated state, the mold is inserted between the time when the joint is set in the mold and the time when the injection is finished and the product is removed from the mold. The joint is not deformed by the heat of the mold, so that the end face of the outer layer and the surface of the joint are in close contact. Thereafter, when the mold is disassembled and taken out, and the mortar is cured and cured, the joints are joined and fixed to such an extent that they do not easily fall off from the end face of the outer layer until the pipe construction. Further, since the outer layer has a uniform thickness and no thin portion, a durable and lightweight thermally expandable jointed fireproof two-layer pipe joint can be obtained.

  Further, the above-described problem is that in the method of manufacturing a fire-resistant double-layer pipe joint in which the end surface of the outer layer adheres to the end surface of the outer layer, a plurality of concave holes It is also possible to appropriately solve the problem by forming the mortar at intervals and hardening the mortar in a state where a part of the injected mortar enters the recessed hole to fix the joint to the end face of the outer layer. In this case, since the mortar hardened in the concave hole fixes the joint, the bonding state with the outer layer is further strengthened.

  Furthermore, instead of the concave hole of the annular thermally expandable joint, a through-hole penetrating the front and back of the joint is formed, and a part of the injected mortar is exuded to the surface of the joint through the through-hole. The above problem can also be solved by fixing the joint to the end face of the outer layer by curing with, and in this case, the columnar mortar hardened in the through-hole locks the joint, so the outer layer and the joint The joining and fixing state is further improved.

  A cutout through hole is formed in the peripheral edge of the annular thermally expandable joint, and the joint is cured in a state in which a part of the mortar to be ejected is exuded to the surface of the joint through the cutout through hole. By fixing to the end face of the outer layer, the joint fixing state of the joint and the outer layer can be improved.

  Further, the annular thermally expandable joint forms an annular groove on the back surface contacting the end surface of the outer layer of the mortar, and the mortar is cured in a state where a part of the injected mortar enters the groove. Fixing the joint to the end face of the outer layer can also improve the joint state between the joint and the outer layer.

  The outer wall surface constituting the annular groove is formed on a slope inclined outward to the groove so as to widen the groove opening, and the inner wall surface constituting the groove is formed in the groove opening. By forming an overhanging slope inclined to the inside of the groove so as to narrow the groove, the injected mortar can easily enter the inside of the groove, and after the mortar hardens, it engages with the overhanging slope. The joints are less likely to fall off.

  When injection molding is performed using the thermally expandable joints having the above-described various configurations, at least a part of the part where the injection mold comes into contact with the joints, if possible, all are brought into a non-heated state. It is possible to produce a heat-resistant double-layer pipe joint with a heat-expandable joint that prevents deformation of the heat-expandable joint that is easily deformed by the influence and has good adhesion to the injected mortar.

  Further, the annular hole of the thermally expandable joint is formed substantially equal to the outer diameter of the joint on the outer side near the end of the synthetic resin pipe joint, and the diameter is enlarged on the inner side near the middle part of the joint. By forming a taper hole and providing a mortar entry space between the peripheral surface of the synthetic resin pipe joint and the annular hole, the joint area between the mortar and the joint is expanded, and the joint fixing state of the joint and the outer layer is further improved. Thus, the above-mentioned problems can be appropriately solved, and the operation of fitting the joint to the end portion of the synthetic resin pipe joint can be easily performed by using the tapered hole.

  As the thermally expandable joint, one containing an epoxy resin is used, and a mortar containing ordinary Portland cement is used. Preferably, the composition of the thermally expandable joint is 35 ± 5% by mass, and the mortar When the composition of ordinary Portland cement is 45 ± 10% by mass, the joint between the joint and the outer layer becomes strong.

  According to the present invention, in a heated injection mold, a synthetic resin pipe joint in which an annular thermally expandable joint having a width substantially equal to the thickness of the outer layer of the mortar is fitted to the end is set in advance. At the same time as the outer layer is formed by injection molding of the mortar, the joint is attached to the end face of the outer layer, and this is taken out from the mold to cure the mortar. The part where the injection mold comes into contact with the thermally expandable joint Since at least a part is in an unheated state, the thermally expandable joint can be fixed to the end face of the outer layer without deformation, and there is no need to affix the thermally expandable joint to the pipe connection end of the refractory double-layer pipe joint Since there is no deformation of the joint, the joint can be attached to the entire end face of the outer layer of the mortar, so that sufficient adhesion can be obtained, and the mortar thickness does not increase. Obtained double-layer pipe joint That. Moreover, since the thickness of the thermally expandable joint appears in a striped shape at the pipe connection portion after the pipe construction, it is easy to check the setting condition of the joint from the outside.

  A plurality of recessed holes are formed at intervals on the back surface where the annular thermally expandable joint contacts the end surface of the outer layer of the mortar, and the mortar is cured with a part of the injected mortar entering the recessed hole. By doing so, the joint has an effect that the joint state with the outer layer is improved by the mortar that has entered the concave hole, and in addition to the above-described effects, the joint can be firmly fixed to be easily removed.

  Further, through holes are formed through the front and back surfaces of the annular thermally expansible joint, and a part of the injected mortar is cured in a state of leaching to the surface of the joint through the through holes. The joint is firmly fixed to the end face of the outer layer by the columnar mortar in the hole, and a work for attaching the joint is not required, so that a lightweight and durable fireproof two-layer pipe joint is obtained.

  Further, a notch through hole is formed in the periphery of the annular thermally expandable joint, and a part of the mortar having a normal temperature to be injected is cured in a state of leaching to the surface of the joint through the notch through hole. Thus, the joint is firmly fixed to the end face of the outer layer by the columnar mortar in the notch through hole, and the same effect as in the above case can be obtained.

  An annular groove is formed on the back surface of the thermally expandable joint, and the injected mortar enters the groove and is hardened, because the joint is anchored by the annular mortar filling the groove. The joint can be firmly fixed to the outer layer, and the wall surface of the groove is composed of an inclined surface inclined to the outside of the recessed groove and an overhanged inclined surface inclined to the inside of the recessed groove. The mortar rotates evenly in the groove, and after the hardening, the mortar and the joint are engaged by the overhang portion, so that the joint can be further firmly fixed.

  Even when using a heat-expandable joint with concave holes, through holes, notched through holes, or concave grooves, deformation of the joints is achieved by making the part where the injection mold contacts the joints unheated. Therefore, the joint can be attached more firmly.

  An annular hole in the thermally expandable joint is formed to be substantially equal to the outer diameter of the joint on the outer side near the end of the synthetic resin pipe joint, and the diameter is increased on the inner side near the middle part of the joint. By forming the joint, it becomes easy to fit the joint to the end of the synthetic resin pipe joint. When the joint is fitted, the mortar is placed between the peripheral surface of the synthetic resin pipe joint and the annular hole. An entrance space is formed, and when the mortar enters the space and hardens, the joint between the joint and the outer layer becomes stronger. Of course, there is an effect that a light-weight and durable fire-resistant double-layer pipe joint is obtained without the need for attaching a joint.

  If the heat-expandable joint contains an epoxy resin and the mortar contains ordinary Portland cement, the familiarity between the outer layer and the joint will be improved, and the joint between the two will become stronger. When the composition of the epoxy resin of the expandable joint is 35 ± 5% by mass and the composition of the normal Portland cement of the mortar is 45 ± 10% by mass, a large joining state is obtained, and no work for pasting the joint is required. A lightweight and durable fireproof double-layer pipe joint is obtained.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described. FIG. 1 shows an embodiment in which the present invention is applied to the production of an elbow-type fireproof two-layer pipe joint. Reference numeral 3 denotes a fire-resistant double-layer pipe joint, and reference numeral 3 denotes a ring-shaped uniform thermal expansion joint provided at the end of the fire-proof double-layer pipe joint 1. This fire-resistant double-layer pipe joint 1 is a synthetic resin pipe made of 90 ° -curved hard polyvinyl chloride having pipe connection ends 4 and 4 at both ends, which are enlarged so as to receive the ends of the fire-resistant double-layer pipe 2. The joint 5 is constituted by an outer layer 6 made of mortar formed by injection molding covering the outer periphery thereof. The fireproof two-layer pipe 2 is composed of a synthetic resin inner pipe 7 made of hard vinyl chloride and a mortar outer pipe 8 covering the outer periphery thereof. When injection molding mortar, if the mold temperature is not heated to about 60 ° C or higher, preferably about 90 ° C with a heater or the like, the mortar will adhere to the inner surface of the mold and the mold will be disassembled. When the product is taken out, the outer layer 6 of the mortar is broken, and the outer layer 6 having a clean predetermined shape cannot be formed.

  The thermal expansion joint 3 starts thermal expansion at about 200 ° C., expands about 4 to 10 times, and closes the gap between the connection portion of the fire-resistant double-layer pipe joint 1 and the fire-resistant double-layer pipe 2. In such a case, it is possible to prevent the internal synthetic resin pipe joint 5 and the inner pipe 7 from spreading due to heat spreading from the gap, and as a result, it is possible to prevent the fire from spreading to the upper room or the adjacent room.

  The thermally expandable joint 3 is desirably attached with a good appearance and sufficient adhesive force at the same time when the outer layer 6 of mortar is injection molded on the outer periphery of the synthetic resin pipe joint 5. The thermally expandable joint 3 having the annular hole 9 corresponding to the outer diameter of the end 4 of the synthetic resin pipe joint 5 as shown in FIGS. 2 and 3 is formed as shown in FIG. 5 is fitted into the end portions 4 and 4 and set in an injection mold 13 heated to 90 ° C., for example (FIG. 5). Then, a mortar 17 having a room temperature is injected from the mortar inlet 15 into the space corresponding to the thickness of the outer layer 6 existing between the synthetic resin pipe joint 5 and the mold 13, and the mortar is filled to every corner of the space. Since the expandable joint 3 is easily deformed by heat and causes the above-described disadvantages, the mold lid 13 prevents the deformation of the closed lid portion 13a in contact with the thermally expandable joint 3 by making it unheated. When the mold 13 is disassembled when the mortar 17 is filled, the outer layer 6 of the mortar is formed on the outer periphery of the synthetic resin pipe joint 5, and the thermally expandable joint 3 is attached to the end surface of the outer layer 6. When the outer layer 6 is cured and cured, the joint 3 is fixed to the end face thereof, and the fire-resistant two-layer pipe joint 1 with the thermally expandable joint is obtained without the above-mentioned difficulties and troubles. As a means for obtaining this non-heated state, in the embodiment, the closed lid portion 13a constituting the mold 13 is left at room temperature before filling with the mortar, and is kept in the non-heated state. You may make it cool to normal temperature grade. By making the mold in such a non-heated state, deformation of the thermally expandable joint 3 is prevented, and as a result, the joint 3 is bonded to the entire end surface of the outer layer 6 and the joint 3 is formed when the mortar is cured. It comes to join strongly with the end face. You may make it make all the parts of the metal mold | die 13 which contact this joint 3 into a non-heating state. Note that the illustrated mold 13 is a two-part mold having a horizontal surface and a paper surface, and when disassembling or assembling, one of the molds moves in a direction perpendicular to the paper surface and is closed. The lid portion 13a was moved in the horizontal direction with respect to the paper surface. The mortar injection time is about 2 to 3 seconds for a standard product, and the time for the thermally expandable joint 3 to contact with the molds 13 and 13a is about 5 seconds, including the assembly and disassembly time for the dies before and after that. It is.

The thermally expandable joint 3 includes a joint (joint A) composed of 6 ± 3 mass% of thermally expandable graphite (graphite type), 59 ± 5 mass% of an inorganic filler, and 35 ± 5 mass% of an epoxy resin, and thermal expansion. A joint (joint B) comprising 13 ± 5% by mass of graphite (graphite-based), 33 ± 5% by mass of aluminum hydroxide, 33 ± 5% by mass of ethylene propylene rubber, 21 ± 5% by mass of process oil or the like is used. The color of these joints is dark gray because graphite is mixed therein. As the mortar 17, a general mortar composed of ordinary Portland cement 45 ± 10 mass%, inorganic fine aggregate / inorganic admixture 50 ± 10 mass%, and organic fiber 5 ± 1 mass% is used. The injection pressure of the mortar was 90 kg / cm ² .

In order to investigate the adhesion and fixing state of the outer layer 6 and the joint A, the joint A is fitted to both ends 4 of the elbow type synthetic resin pipe joint 5 having an outer diameter of the end 4 of 83 mm, and this is not heated. A portion 13a and an inside of an injection mold 13 heated to 90 ° C. are set, a normal temperature mortar is injected from a mortar injection port 15, and an outer layer 6 made of a mortar having a thickness of 10 mm and having the above composition is formed into a synthetic resin pipe joint 5 Formed on the outer periphery. The thickness of the joint A is 4 mm, the outer diameter is 103 mm, and the diameter of the annular hole 9 is 82.8 mm. The mold 13 is disassembled and the refractory double-layer pipe joint 5 of the semi-finished product in which the mortar is uncured and the joint A is attached and attached to the end face of the outer layer 6 is taken out and cured for 24 hours to cure the mortar. A joint 1 was obtained. The joint A was not twisted or distorted by waves and joined to the end face of the outer layer without shifting. And when the peeling test of this joint A was done, it did not peel to the load of 4 kg / cm < ² >. This peeling load is a load that is not applied to the joint in a normal state until the fire-resistant double-layer pipe joint 5 is manufactured and used for piping construction, and the joint may fall off before the piping construction. Judged not.

  As shown in FIGS. 6 and 7, a plurality of concave holes 18 may be formed in the thermally expandable joint 3 at an appropriate interval on the back surface 10 in contact with the end surface of the outer layer 6. In the case of a joint, when it is fitted into the end of the synthetic resin pipe joint 5 and set in the mold 13 and the mortar 17 is injected to form the outer layer 6, a part of the mortar enters the inside of the concave hole 18. The fireproof two-layer pipe joint 1 in the entered state is obtained. Even if this is taken out from the mold 13, the joint 3 is not deformed, and the mortar hardened in the concave hole 18 improves the joining and fixing properties between the end face and the joint 3.

When the concave hole 18 having a depth of 2.5 mm was formed in the joint B having a thickness of 4 mm and the fireproof two-layer pipe joint 1 was manufactured by injection molding in the same manner as the joint A, the peel load was measured. It did not peel up to 4 kg / cm ² . The dimensions of the joint B are the same as the joint A, and the dimensions of the synthetic resin pipe joint 5 are the same as those of the joint A. This peeling load is a load that is not applied to the joint in a normal state until the fireproof double-layer pipe joint 5 is manufactured and used for piping as described above. It can be determined that it will not fall out.

Furthermore, as shown in FIGS. 8 and 9, the annular thermally expandable joint 3 made of the joint B is changed to one having through holes 12 penetrating the front and back of the joint, and the joint 3 is made of a synthetic resin. The outer layer 6 of mortar was injection-molded after being set in the injection mold 13 while being fitted to the end 4 of the pipe joint 5. The dimensions of the synthetic resin pipe joint 5 and the joint 3, the composition of the mortar, and the injection conditions are the same as those in the example of FIG. 5. The injected mortar exudes from the back surface 10 of the joint to the front surface 11 through the through-holes 12, and is cured in the through-holes 12 when the mortar is cured by taking out from the mold 13 without deformation of the joint 3. The mortar column was firmly fixed to the end surface of the outer layer 6. The peel load of the joint 3 was 6 kg / cm ² , and the strength was sufficient to prevent the joint from falling off the outer layer 6.

Further, the annular thermally expandable joint 3 made of the joint B is changed to a notch formed in the peripheral edge of the joint as shown in FIG. 10, and the joint 3 is similar to the above case. In a state of being fitted to the end 4 of the synthetic resin pipe joint 5, it was set in an injection mold 13 and the outer layer 6 of mortar was injection molded. The dimensions of the synthetic resin pipe joint 5 and the joint 3, the composition of the mortar, and the injection conditions are the same as those in the example of FIG. 5. The injected mortar oozes from the back surface 10 of the joint through the notched through hole 19 to the front surface 11, and the joint 3 is not deformed. When this is taken out from the mold 13 and the mortar is cured, the notched through hole It was firmly fixed to the end face of the outer layer 6 by a mortar column cured in 19. The peel load of the joint 3 was 6 kg / cm ² .

In order to more firmly fix the thermally expandable joint 3 to the outer layer 6, the inner diameter of the annular hole 9 of the joint 3 corresponds to the end 4 of the synthetic resin pipe joint 5 as shown in FIGS. 11 and 12. The outer side 9a is formed to be substantially equal to the outer diameter D of the end portion 4, and the inner side 9b corresponding to the inner side of the joint 5 is enlarged to D + α to form a tapered hole. When the annular hole 9 is fitted in the end 4 of the synthetic resin pipe joint 5 and set in the split mold 13 of the injection molding machine as shown in FIG. 13, the peripheral surface of the synthetic resin pipe joint 5 A wedge-shaped mortar entrance space 16 is formed between the annular hole 9 and the annular hole 9. When the mortar 17 is press-fitted from the mortar inlet 15 of the mold 13, a part of the mortar also enters the mortar entry space 16. When the mortar 17 is dried and hardened by demolding from the mold 13, thermal expansion occurs. The joint 3 is hardened while being in close contact with not only the mortar on the end face of the outer layer 6 but also the mortar that has entered the mortar entry space 16, so that the joint 3 is more firmly fixed. When the joint B is used in this example and mortar is injected under the same conditions as in FIG. 5, the joint 3 is not deformed, and the peeling load from the outer layer 6 of the joint 3 is 6.5 kg / cm ^2. Met.

The annular thermally expandable joint 3 made of the joint B was changed to one having an annular groove 20 formed on the back surface 10 of the joint as shown in FIGS. The concave groove 20 has an outer wall surface formed on an inclined surface 21 inclined to the outer side of the concave groove so as to widen the concave groove opening, and the inner wall surface of the concave groove narrows the concave groove opening. It formed in the overhanging slope 22 inclined to the inner side of the ditch | groove. The annular hole 9 is a tapered hole similar to the case of FIG. The joint 3 was set in the injection mold 13 with the end 3 of the synthetic resin pipe joint 5 fitted in the same manner as described above, and the outer layer 6 of mortar was injection molded. The dimensions of the synthetic resin pipe joint 5 and the joint 3, the composition of the mortar, and the injection conditions are the same as those in the example of FIG. 5. In the obtained joint 1, the mortar sufficiently enters the inside of the groove 20 as shown in FIG. 16 even in a short injection time, and the peel load is 7 kg / cm ^2. Did not come off.

  In addition, when manufacturing the fireproof two-layer pipe joint 1 using what the said heat expansible joint 3 formed the concave hole 18, the through-hole 12, the notch through-hole 19, and the concave groove 20, the thickness of a joint is produced. If is large, it is possible to perform injection molding without bringing the mold part in contact with the joint into a non-heated state, but the jointability between the joint 3 and the outer layer 6 is inferior to that in the non-heated state.

Cutaway side view showing an embodiment of the present invention Front view of the thermally expandable joint shown in FIG. 2 is an enlarged cross-sectional view taken along line 3-3 in FIG. Perspective view of a synthetic resin pipe fitting set in an injection mold Cut-away side view of the production state of the fireproof two-layer pipe joint of the present invention Front view of a modified example of thermally expandable joint Fig. 6 is an enlarged cross-sectional view taken along line 7-7. Front view of another modification of thermally expandable joint Enlarged sectional view taken along line 9-9 in FIG. Front view of still another modification of the thermally expandable joint Front view of an embodiment in which the annular hole of the thermally expandable joint is formed into a tapered hole FIG. 11 is an enlarged cross-sectional view taken along line 12-12 of FIG. FIG. 11 is a cut side view of the production state in which the thermally expandable joint shown in FIG. 11 is set in a mold. Back view of an embodiment in which a concave groove is formed on the back surface of the thermally expandable joint Sectional view taken along line 15-15 in FIG. Expanded cross-sectional view of the manufactured refractory double-layer pipe joint

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fireproof two-layer pipe joint, 2 Fireproof two-layer pipe, 3 Thermal expansion joint, 4 End part, 5 Synthetic resin pipe joint, 6 Outer layer, 9 Annular hole, 9a Outside, 9b Inside, 10 Back, 11 Surface, 12 Through hole, 13 injection mold, 13a part, 16 mortar entry space, 17 mortar, 18 concave hole, 19 notch through hole, 20 concave groove, 21 slope, 22 overhang slope,

Claims (10)

  An annular thermally expandable joint having a width substantially equal to the thickness of the outer layer is fitted on the outer periphery of the end portion of the synthetic resin pipe joint where the outer layer of mortar is formed, and this is heated in an injection mold. After forming the outer layer in contact with the thermally expandable joint around the synthetic resin pipe joint with the injected mortar, the mortar is removed from the mold and cured to heat the end surface of the outer layer. A method for producing a fireproof two-layer pipe joint with an expandable joint attached thereto, characterized in that at least a part of the portion where the injection mold comes into contact with the thermally expandable joint is unheated. Manufacturing method of jointed fireproof two-layer pipe joint.   An annular thermally expandable joint having a width substantially equal to the thickness of the outer layer is fitted on the outer periphery of the end portion of the synthetic resin pipe joint where the outer layer of mortar is formed, and this is heated in an injection mold. After forming the outer layer in contact with the thermally expandable joint around the synthetic resin pipe joint with the injected mortar, the mortar is removed from the mold and cured to heat the end surface of the outer layer. In the method of manufacturing a fire-resistant double-layer pipe joint with an expandable joint attached, a plurality of concave holes are formed at intervals on the back surface where the annular thermally expandable joint is in contact with the end surface of the outer layer of the mortar and injected. A method for producing a thermally expandable jointed refractory double-layer pipe joint, characterized in that the joint is fixed to the end face of the outer layer by curing the mortar in a state where a part of the mortar enters the recessed hole.   An annular thermally expandable joint having a width substantially equal to the thickness of the outer layer is fitted on the outer periphery of the end portion of the synthetic resin pipe joint where the outer layer of mortar is formed, and this is heated in an injection mold. After forming the outer layer in contact with the thermally expandable joint around the synthetic resin pipe joint with the injected mortar, the mortar is removed from the mold and cured to heat the end surface of the outer layer. In the method for producing a fireproof two-layer pipe joint with an expandable joint attached, a through-hole penetrating the front and back is formed in the annular thermally expandable joint, and a part of the injected mortar is passed through the through-hole. A method for producing a thermally expandable jointed refractory double-layer pipe joint, characterized in that the joint is fixed to an end face of the outer layer by curing in a state of oozing to the surface of the joint.   An annular thermally expandable joint having a width substantially equal to the thickness of the outer layer is fitted on the outer periphery of the end portion of the synthetic resin pipe joint where the outer layer of mortar is formed, and this is heated in an injection mold. After forming the outer layer in contact with the thermally expandable joint around the synthetic resin pipe joint with the injected mortar, the mortar is removed from the mold and cured to heat the end surface of the outer layer. In a method of manufacturing a fireproof two-layer pipe joint with an expandable joint attached, a notch through hole is formed in the periphery of the annular thermally expandable joint, and a part of the injected mortar is passed through the notch through hole. Then, the joint is fixed to the end face of the outer layer by curing in a state of oozing to the surface of the joint.   An annular thermally expandable joint having a width substantially equal to the thickness of the outer layer is fitted on the outer periphery of the end portion of the synthetic resin pipe joint where the outer layer of mortar is formed, and this is heated in an injection mold. After forming the outer layer in contact with the thermally expandable joint around the synthetic resin pipe joint with the injected mortar, the mortar is removed from the mold and cured to heat the end surface of the outer layer. In the method of manufacturing a fireproof two-layer pipe joint with an expandable joint attached, the annular thermally expandable joint forms an annular concave groove on the back surface in contact with the end surface of the outer layer of the mortar, and a part of the injected mortar is A method for producing a thermally expandable jointed refractory double-layer pipe joint, characterized in that the joint is fixed to the end face of the outer layer by curing the mortar while entering the concave groove.   The outer wall surface of the annular groove is formed on an inclined surface that is inclined to the outside of the groove so as to widen the opening of the groove, and the inner wall surface of the groove is recessed so as to narrow the opening of the groove. 6. The method for producing a thermally expandable jointed refractory double-layer pipe joint according to claim 5, wherein the joint is formed in an overhanging slope inclined inward.   An annular hole in the thermally expandable joint is formed to be substantially equal to the outer diameter of the joint on the outer side near the end of the synthetic resin pipe joint, and the diameter is increased on the inner side near the middle part of the joint. The thermally expandable jointed refractory according to any one of claims 1 to 5, wherein a mortar entry space is provided between the peripheral surface of the synthetic resin pipe joint and the annular hole. A method for manufacturing a two-layer pipe joint.   6. The thermally expandable jointed refractory joint according to claim 2, wherein at least a part of the portion where the injection mold comes into contact with the thermally expandable joint is brought into an unheated state. A method for manufacturing a layered pipe joint.   The thermally expandable joint according to any one of claims 1 to 5, wherein the thermally expandable joint contains an epoxy resin, and mortar contains ordinary Portland cement. A manufacturing method for a fire-resistant double-layer pipe joint.   9. The thermal expansibility according to claim 8, wherein the composition of the epoxy resin of the thermally expansible joint is 35 ± 5% by mass, and the composition of ordinary Portland cement of mortar is 45 ± 10% by mass. Manufacturing method of jointed fireproof two-layer pipe joint.

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