JP6453670B2 - Outer layer damage prevention device for fireproof double-layer pipe joints - Google Patents

Description

  The present invention relates to an outer layer damage prevention device for a fireproof two-layer pipe joint having a configuration in which the outer surface of a synthetic resin joint inner pipe is covered with mortar.

  The fire-resistant double-layer pipe joint is characterized by being lightweight and fire-resistant, and the outer layer of the mortar covering the outer surface is manufactured by injection molding with a synthetic resin joint inner pipe placed in a mold. It is common. The molding state will be described in detail with reference to FIGS. 1 and 2. First, a joint inner pipe b made of synthetic resin such as vinyl chloride is accommodated in the molding die a, and the mold a, the joint inner pipe b, The fiber-containing mortar e is press-fitted into the gap c. When the mortar e fills the gap c, the mold a is separated, the joint inner tube b in which the mortar outer layer f is formed is taken out, and the outer layer f is cured and cured, as shown in FIG. A refractory two-layer pipe joint g having an outer sheath layer f is obtained.

  The mortar inlet d is provided at a position where the mortar reaches the entire circumference of the joint inner pipe b in a short time. In this example, the mortar e passes the peripheral surface of the joint inner pipe b from the inlet d as indicated by the arrow in FIG. In this way, it advances in two ways, and the flow ends merge at the position opposite to the inlet d and fuse together. At this merged position, a thin line called a weld line h is generated, and the outer layer f of this portion is fused by butting and the reinforcing fibers mixed in the mortar are not mixed in, so the outer layer f is more than the other portions. Tensile strength decreases. This fire-resistant double-layer pipe joint g is greatly different in the coefficient of thermal expansion between the joint pipe b made of vinyl chloride and the jacket layer f made of mortar. When thermal expansion occurs due to the cause, the outer cover layer f in a weak portion near the weld line h may be cracked and damaged by the expansion force. If the joint inner pipe b is exposed to the outside from the damaged portion of the jacket layer f, the joint inner pipe b may be burned out in the event of a fire, which is not preferable for disaster prevention. Reference symbol i denotes a branch pipe connecting portion.

  Conventionally, as a means for preventing the damage of the envelope layer f due to such thermal expansion, for example, immediately after forming the envelope layer f, a single stapler needle is driven across the weld line h, and the tension of the stapler needle is used. A method for preventing cracks in the weld line h of the outer sheath layer f, and winding a piece of paper around the joint inner tube b and placing it in a mold to form the outer sheath layer f, thereby forming the inner sheath tube b and the outer sheath. There has also been proposed a method (see Patent Document 1) in which a gap corresponding to the thickness of the paper piece is provided between the layer f and the thermal expansion of the joint inner pipe b is absorbed in the gap (see Patent Document 1). The sheet | seat which has a protrusion is affixed on the surrounding surface part of the joint inner pipe | tube b corresponding to the location where generation | occurrence | production is anticipated, and the coating layer f and this protrusion which are formed in a surrounding surface are couple | bonded together. Weld line h due to thermal expansion by solidification How to prevent the definitive cracking (see Patent Document 2) has been proposed.

JP 2004-197926 A JP 2002-340237 A

In the above-described means for preventing damage to the outer cover layer by the stapler needle, since the strength of the outer cover layer is weakened, a large number of stapler needles cannot be provided, and there is an inconvenience that sufficient damage prevention cannot be performed. Since the appearance of the surface was impaired, the mortar was overlaid with a trowel so as to hide the needle. In addition, in the type of providing a gap by a piece of paper or pasting a sheet having a protrusion, there is a disadvantage that it takes work time because it involves an operation of fixing the piece of paper to the joint inner pipe with an adhesive tape after winding the piece of paper. When a sheet having protrusions is used, not only does it take time to affix the sheet to the inner pipe of the joint, but there is a disadvantage that it takes time to form the outer cover layer because the sheet hinders the flow of mortar in the mold. It was. Furthermore, fire-resistant double-layer pipe joints are often placed in invisible places such as under the floor and duct space, and after the fire-proof double-layer pipe joints have been installed, despite the above-mentioned means for preventing damage. When the jacket layer was damaged by thermal expansion, it was difficult to find the damage.
An object of the present invention is to provide a means for preventing breakage in a weld line of an outer coat layer which can solve such disadvantages and drawbacks and can be installed relatively easily and has good fire resistance.

In the present invention, in a fireproof two-layer pipe joint having a mortar jacket layer formed by injection molding on the outer surface of a synthetic resin joint inner pipe, a plate-like separator is provided at a position substantially along the weld line of the jacket layer. The above-mentioned object is achieved by embedding in a partition shape and separating the outer cover layer at that position.
The plate-like separator may be constituted by a plate-like separator made of a material that does not burn by flame or hardly burned by flame, or may be constituted by a fire-resistant plate-like separator having thermal expansion properties. it can.
Immediately after forming the mortar cover layer, the plate-like separator is embedded in the partition layer by pushing it into a position substantially along the weld line, or the joint corresponding to the place where the weld line is expected to occur. It is also possible to embed the plate-like separator at the position of the outer peripheral surface of the inner pipe by fixing the plate-like separator in advance in the form of a screen and then molding the jacket layer.
If the lower end of the plate-like separator that is embedded in the partition is formed in a wedge shape, it becomes easier to push into the soft outer layer immediately after molding, and the cross-sectional shape of the plate-like separator If a gap is formed between the separator and the jacket layer, the gap is covered at the top of the T-shape, so that in the event of a fire, the flame will enter the gap. If the plate-like separator is provided with means for engaging with the jacket layer made of holes or protrusions, the separator will not fall out of the jacket layer.
You may use the plate-shaped body of the structure which disperse | distributed thermal expansible graphite in the laminated body of an inorganic fiber in the separator which has thermal expansibility.

  The sheath layer breakage prevention device of the present invention is such that a plate-like separator is embedded in a partition shape at a position substantially along the weld line of the sheath layer of a fireproof two-layer pipe joint to separate the sheath layer. Thus, when the inner pipe of the fireproof two-layer pipe joint is expanded by thermal expansion or the like, the outer cover layer is separated by the separator and is in a discontinuous state, so that no tensile stress is generated in the outer cover layer. It is possible to prevent breakage such as new cracks from occurring along the weld line. In addition, a plate-like separator made of non-combustible material, flame retardant material, or thermal expansion material is embedded in the part where the outer cover layer is separated. In the event of a fire, this separator blocks the flame and the flame is joined. The inner pipe is prevented from extending, so that the fire resistance of the joint is maintained.

  The outer cover layer is formed by covering the peripheral surface of the joint inner pipe by injection molding, but when the separator is in a soft state immediately after forming the outer cover layer, it is pushed in a partition shape substantially along the weld line. Can be embedded easily. In addition, since the weld line is predictable, the separator is fixed to the outer peripheral surface of the joint inner pipe in the form of a partition with an adhesive at the position of the outer peripheral surface of the joint inner pipe corresponding to the planned generation point. When the inner pipe of the joint is accommodated in the mold and injection-molded, an outer cover layer having a separator embedded therein can be formed at a position corresponding to the weld line, and the work of bonding the separator can be completed in a few seconds, so that workability is good.

  When embedding the separator in the form of a screen immediately after forming the outer cover layer, if the lower end edge of the separator is formed in a wedge shape, it becomes easy to push into the outer cover layer, and the cross-sectional shape of the separator is T-shaped. If formed in the mold, the gap formed between the outer cover layer and the separator due to the curing can be covered with the top of the T-shape, and the flame hardly enters the gap, thereby improving the fire resistance of the joint. If an engagement means including a hole or a protrusion is provided on the plate surface of the separator, it is possible to embed with good engagement with the jacket layer. In addition, when a plate-like body having a structure in which thermally expandable graphite is dispersed in an inorganic fiber laminate is used as a separator, the separator has good elasticity with the mortar of the jacket layer, and the separator and the jacket are elastic. Generation of gaps between the layers can be prevented.

Cut-away side view showing an example of the production state of a fireproof two-layer pipe joint Cut-away plan view along line AA in FIG. 1 is a perspective view of the fireproof two-layer pipe joint of FIG. The perspective view of the Example of this invention Cut side view along line BB in FIG. The perspective view of the thermal expansion material used in the Example shown in FIG. Side view of a variation of thermal expansion material The right side view of the thermal expansion material of FIG. 7 is a cut side view of the thermal expansion material in use in FIG. The perspective view of the other modification of a thermal expansion material The perspective view of the Example which fixed the separator to the pipe in a joint

  The embodiment of the present invention will be described with reference to the drawings. In FIGS. 4 and 5, reference numeral 1 denotes an outer cover made of fiber-mixed mortar by injection molding on the outer surface of a joint pipe 2 made of vinyl chloride in the same manner as in the prior art. 2 shows a refractory two-layer pipe joint having three ports forming layer 3; When the outer cover layer 3 of the fireproof two-layer pipe joint 1 is formed by injection molding, a weld line h as shown in FIG. 3 is formed in the formed outer cover layer, and this portion is the joint inner pipe 2. However, in the present invention, a plate-like separator 4 made of a thermally expandable material is embedded along the weld line generated in the jacket layer 3 to coat the jacket layer 3. In this way, even if the joint inner pipe 2 is expanded in diameter by thermal expansion or the like, the portion separated by the separator 4 of the outer sheath layer 3 is slightly expanded, and the outer diameter of the outer sheath layer 3 is increased due to the increased diameter. The weld line is not broken. Reference numeral 8 denotes a thermally expandable joint provided around each port of the joint inner pipe 2.

  The separator 4 is made of a material having both fire resistance and thermal expansibility, for example, a thermal expansive graphite and a resin mixed with each other and molded into a fire-resistant plate or an inorganic fiber such as glass fiber. It is preferable to use a commercial product such as a fire-resistant plate formed by dispersing graphite and having a volume expansion of about 5 to 6 times when the heat of fire acts. Depending on the usage environment, self-digestible vinyl chloride or a fire-resistant metal plate may be used.

  If the environment where the fireproof two-layer pipe joint 1 is placed is an environment that causes large expansion of the inner pipe 2 of the joint, the covering layer 3 covering the pipe will receive a tensile force due to the expansion. Then, a crack occurs in the jacket layer in the vicinity of the weld line, but in the present invention, since the separator 4 having thermal expansion provided at a position substantially along the weld line separates the jacket layer 3, Although the separated portion slightly expands due to the thermal expansion of the joint inner pipe 2, no new crack is generated in the jacket layer 3. Further, if the separator 4 is formed of a thermal expansion material, when the fireproof double-layer pipe joint 1 is exposed to a fire flame, the separator 4 is thermally expanded and closes the separated portion of the jacket layer 3, so that the flame is in the joint. The fire resistance of the joint 1 is maintained without reaching the pipe 2.

  The separator 4 is formed in a plate shape as shown in FIGS. 6 to 8 and 10, and in the case of a three-port fireproof double-layer pipe joint 1, the weld line can be seen in FIG. 3. Since it appears in an L shape from the main body portion to the branch pipe connecting portion 9, it is formed in an L shape so as to fit this portion. After forming the outer cover layer 3 on the outer surface of the joint inner pipe 2 by curing the outer cover layer 3, the fire-resistant two-layer pipe joint 1 is obtained, but the separator 4 is immediately after the outer cover layer 3 is injection molded. When the weld mortar is soft and the weld line is visible, the outer cover layer 3 is pushed along the weld line from the edge of the separator 4 in the thickness direction of the outer cover layer 3, and the edge is the inner pipe 2 of the joint. The outer cover layer 3 is buried so as to be separated into a partition. When the refractory double-layer pipe joint 1 is cured after burying, the weld line portion of the jacket layer 3 is separated into right and left as shown in FIGS. 4 and 9, and the separator 4 is interposed between the hardened jacket layers 3. The joint 1 having the configuration is obtained. The separation part of the outer cover layer 3 does not need to be completely separated by the separator 4 and may be in an incomplete separation state in which a thin mortar remains.

  Since the place where the weld line is to be generated can be estimated from the shape of the joint inner pipe 2 and the position of the mortar injection port of the injection mold, the outer cover layer 3 is formed by injection molding as shown in FIG. Before forming, the separator 4 is raised and fixed to the outer surface of the joint inner pipe 2 corresponding to the planned occurrence location in a partition shape with an adhesive or the like, and the joint inner pipe 2 in this state is attached to the injection mold. When the envelope layer 3 is formed by placing and injecting mortar, it is possible to embed a partition separator 4 in which the envelope layer 3 is separated along the weld line. In this case as well, if the outer cover layer 3 is cured and contracted, a slight gap may be formed between the outer cover layer 3 and the separator 4, but if the separator 4 made of a thermal expansion material is used, the separator 4 expands in the event of a fire. Since the gap is closed, the fire resistance of the joint 1 can be maintained. In the case of the joint 1 used in an environment where the level of fire resistance need not be so high, it is possible to use a self-digestible vinyl chloride or refractory metal as the separator 4. is there.

  When the separator 4 is embedded in the jacket layer 3 immediately after the molding of the jacket layer 3, the lower end 5 of the separator 4 is formed in a wedge shape as shown in FIGS. If the part is cut diagonally 6, it is pushed from the corner of the separator 4 as shown in FIG. 9, and the lower end 5 is easily reached to the outer peripheral surface of the joint inner pipe 2 by breaking the mortar jacket layer 3. This makes it easier to embed.

  As described above, when the outer cover layer 3 contracts as the mortar hardens, a gap may be formed between the outer cover layer 3 depending on the material of the separator 4. In order to prevent this gap from being seen from the outside. As shown in FIG. 10, the separator 4 may be formed in a T-shaped cross section. In this case, since the gap is covered with the T-shaped top, it is possible to prevent water and dust from entering the gap, and for example, it is possible to prevent the outer cover layer 3 from being damaged due to freezing of the entered water.

  In order to stably embed the separator 4, an engagement means including a hole 7, a protrusion, or a protrusion with a turn as shown in FIG. 6 may be provided on the plate surface of the separator 4.

  The separator 4 can be manufactured at low cost by using a commercially available material. For example, the heat-expandable graphite is dispersed in a laminate of a heat-resistant heat-expandable material in which heat-expandable graphite is mixed with synthetic rubber or inorganic fibers such as glass fibers. It is preferable to use a fire-resistant thermal expansion material. When the separator 4 made of the latter thermal expansion material is used, the outer layer 3 has good bondability with the mortar and is elastic, so that the above-mentioned gap is hardly generated, and the appearance of the fire-resistant double-layer pipe joint 1 However, since the latter separator 4 is relatively soft, it is preferable to form the jacket layer 3 after being fixed to the joint inner pipe 2 in advance as shown in FIG.

A rigid polyvinyl chloride 3-port joint inner pipe 2 is housed in a disassembly mold, and fiber-mixed mortar is press-fitted into the mold to form a jacket layer 3 on the peripheral surface of the joint inner pipe 2; The mold was disassembled to produce a fireproof two-layer pipe joint 1. While the jacket layer 3 of the joint 1 was soft, a separator 4 made of a thermal expansion material having the shape shown in FIG. 10 was pushed in along a weld line that can be visually observed. Next, the jacket layer 3 of the joint 1 was cured in a curing room. The composition of the fiber-mixed mortar is usually 35 to 55% Portland cement, 35 to 55% lightweight aggregate, and 2 to 8% organic fiber. The composition of the thermally expandable material is 9% thermally expandable graphite and the inorganic filler 82. %, Acrylic resin 9%.
The joint 1 was tested for 120 minutes in an atmosphere of 60 ° C., but no crack was observed in the outer cover layer 3. For comparison, a joint without a separator was manufactured by the same manufacturing method as described above, and the same test was performed at 60 ° C. for 120 minutes. However, cracks occurred in the weld line portion.

DESCRIPTION OF SYMBOLS 1 Fireproof two-layer pipe joint 2 Joint inner pipe 3 Outer layer 4 Separator 5 Lower end part 6 Cut 7 Hole

Claims (9)

  In a fire-resistant double-layer pipe joint having a mortar jacket layer formed by injection molding on the outer surface of a joint pipe made of synthetic resin, a plate-like separator is formed in a partition shape at a position substantially along the weld line of the jacket layer. An apparatus for preventing damage to a covering layer in a refractory two-layer pipe joint, characterized in that the covering is buried and the covering layer at that position is separated.   2. The jacket layer in a fire-resistant double-layered pipe joint according to claim 1, wherein the plate-like separator is constituted by a plate-like separator made of a material that does not burn by flame or hardly burns by flame. Damage prevention device.   The apparatus for preventing damage to a jacket layer in a fire-resistant double-layer pipe joint according to claim 1, wherein the plate-like separator is composed of a fire-resistant plate-like separator having a thermal expansion property.   2. The fireproof double-layer pipe according to claim 1, wherein the plate-like separator is embedded by being pushed into a position substantially along a weld line of the outer cover layer immediately after forming the outer cover layer of the mortar. Outer layer damage prevention device for joints.   The embedding layer is formed by fixing the plate-like separator in a partition shape in advance at a position of an outer peripheral surface of the joint inner pipe corresponding to a place where the weld line is to be generated. The outer-layer damage prevention apparatus in the fire-resistant two-layer pipe joint as described in 1-3.   The apparatus for preventing damage to an outer layer of a fireproof double-layer pipe joint according to claim 4, wherein a lower end portion of the plate-like separator embedded by being pushed into the partition is formed in a wedge shape.   The cross-sectional shape of the said plate-shaped separator was formed in the T shape, The jacket layer damage prevention apparatus in the fireproof two-layer pipe joint of Claim 1 characterized by the above-mentioned.   2. An apparatus for preventing damage to a jacket layer in a refractory two-layer pipe joint according to claim 1, wherein a means for engaging with the jacket layer comprising holes or protrusions is provided on a plate surface of the plate-like separator.   4. The jacket layer in a refractory double-layer pipe joint according to claim 3, wherein the thermal expandable separator is composed of a plate-shaped body having a structure in which thermally expandable graphite is dispersed in a laminate of inorganic fibers. Damage prevention device.

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