阅读说明：本技术 一种供暖保温管弯头 (Heating heat preservation pipe elbow ) 是由 储超超 李超 于 2019-09-20 设计创作，主要内容包括：本发明属于供暖设备技术领域,具体涉及一种供暖保温管弯头。本发明的外套管采用分体式结构,减少了外套管受冷温度降低时产生的褶皱,降低了外套管的内应力,避免了外套管开裂的情况发生；本发明供暖保温管弯头的端部设置有与保温直管连接的密封机构,避免了热量流失,进一步提高了保温性能。本发明的密封机构通过第四限位环和第五限位环与第一空腔的配合,以及第二限位环和第三限位环与第二空腔的配合,确保了保温管弯头的保温层和直管的保温层之间不会产生轴向滑动,提高了供暖保温管弯头与保温直管连接处的密封性,提高了保温性能。(The invention belongs to the technical field of heating equipment, and particularly relates to a heating insulation pipe elbow. The outer sleeve of the invention adopts a split structure, reduces the wrinkles generated when the cooling temperature of the outer sleeve is reduced, reduces the internal stress of the outer sleeve and avoids the outer sleeve from cracking; the end part of the heating heat-preservation pipe elbow is provided with the sealing mechanism connected with the heat-preservation straight pipe, so that heat loss is avoided, and the heat-preservation performance is further improved. The sealing mechanism ensures that the heat-insulating layer of the heat-insulating pipe elbow and the heat-insulating layer of the straight pipe cannot slide axially through the matching of the fourth limiting ring and the fifth limiting ring with the first cavity and the matching of the second limiting ring and the third limiting ring with the second cavity, improves the sealing property of the joint of the heat-insulating pipe elbow and the heat-insulating straight pipe, and improves the heat-insulating performance.)

1. the utility model provides a heating heat preservation union elbow, by interior to including outer tube (1), heat preservation (2) and steel pipe (3), its characterized in that outward: the end part of the heating heat-preservation pipe elbow is provided with a sealing mechanism (4) connected with the heat-preservation straight pipe; the outer sleeve (1) comprises an upper outer sleeve (101) and a lower outer sleeve (102), and the upper outer sleeve (101) and the lower outer sleeve (102) are connected through a plug (103) and a socket (104); the upper outer sleeve (101) consists of more than two upper outer sleeves (105), the lower outer sleeve (102) consists of lower outer sleeves (106), and the number of the lower outer sleeves (106) is the same as that of the upper outer sleeves (105); a circle of grooves (107) with the same depth are formed at the joint of the outer surfaces of the adjacent upper outer ring (105) and the adjacent lower outer ring (106); a hoop strip (108) is matched in the groove (107), the outer surface of the hoop strip (108) is flush with the outer surfaces of the upper outer sleeve (105) and the lower outer sleeve (106), and a first mushroom fastener (109) along the length direction of the hoop strip (108) is fixedly arranged on the inner surface of the hoop strip (108); a first buckle groove (110) matched with the first mushroom buckle (109) is formed in the groove (107);

The heat-insulating layer (2) consists of an upper heat-insulating layer (201) and a lower heat-insulating layer (202), and a limiting strip (203) and a first limiting groove (204) which are matched with each other are formed on the joint surface of the upper heat-insulating layer (201) and the lower heat-insulating layer (202); the inner surfaces of the upper outer ring (105) and the lower outer ring (106) and the outer surfaces of the upper heat-insulating layer (201) and the lower heat-insulating layer (202) form a first limiting ring (111) and a second limiting groove (205) which are matched with each other.

2. The heating insulating pipe elbow according to claim 1, characterized in that: the outer surface of the steel pipe (3) is welded with three groups of upper fins (301) and three groups of lower fins (302), the upper fins (301) are embedded into the upper heat-insulating layer (201), and the lower fins (302) are embedded into the lower heat-insulating layer (202).

3. The heating insulating pipe elbow according to claim 1, characterized in that: the end part of the steel pipe (3) is fixedly connected with the straight steel pipe (5) of the heat-preservation straight pipe through a flange (6).

4. The heating insulating pipe elbow according to claim 1, characterized in that: the sealing mechanism (4) comprises an upper heat-insulating layer (201) and a second limiting ring (401) protruding from the end part of a lower heat-insulating layer (202), the end part of the second limiting ring (401) is fixedly connected with a third limiting ring (402), the outer diameters of the second limiting ring (401) and the third limiting ring (402) are the same, and the inner diameter of the second limiting ring (401) is larger than that of the third limiting ring (402); a first cavity (403) with an opening on the side is surrounded by the end parts of the heat-insulating layer (201) and the lower heat-insulating layer (202) and the second limiting ring (401) and the third limiting ring (402); the sealing mechanism (4) further comprises a fourth limiting ring (701) formed by protruding the end part of the straight pipe heat-insulating layer (7), the end part of the fourth limiting ring (701) is fixedly connected with a fifth limiting ring (702), the outer diameters of the fourth limiting ring (701) and the fifth limiting ring (702) are the same, and the inner diameter of the fourth limiting ring (701) is larger than that of the fifth limiting ring (702); a second cavity (703) with an opening on the side is enclosed by the end part of the straight pipe heat-insulating layer (7), the fourth limiting ring (701) and the fifth limiting ring (702); the fourth limiting ring (701) and the fifth limiting ring (702) are matched with the first cavity (403) mutually; the second limiting ring (401) and the third limiting ring (402) are matched with the second cavity (703).

5. The heating insulating pipe elbow according to claim 4, characterized in that: iron sheets (8) are fixedly arranged on the inner sides of the second limiting ring (401) and the fourth limiting ring (701), and magnetic sheets (9) are fixedly arranged on the inner sides of the third limiting ring (402) and the fifth limiting ring (702) corresponding to the positions of the iron sheets (8).

6. The heating insulating pipe elbow according to claim 1, characterized in that: an elastic sealing strip (10) which is propped against the groove (107) is fixedly stuck at the edge of the hoop strip (108); one end of the hoop strip (108) is fixedly connected with a second mushroom buckle (112), and the other end of the hoop strip (108) is provided with a second buckle groove (113) matched with the second mushroom buckle (112).

7. The heating insulating pipe elbow according to claim 1, characterized in that: the outer surfaces of the upper outer sleeve (105) and the lower outer sleeve (106) are fixedly connected with a sixth limiting ring (114), the inner surface of the sixth limiting ring (114) is fixedly connected with third mushroom buckles (115) which are arranged at equal intervals, and the outer surface of the straight pipe outer sleeve (11) is provided with a third buckle groove (1101) matched with the third mushroom buckles (115).

Technical Field

The invention belongs to the technical field of heating equipment, and particularly relates to a heating insulation pipe elbow.

Background

The heat preservation pipe elbow is one of heat preservation pipe fittings, and the heat preservation elbow is widely used in the turn of liquid, gaseous conveying pipe network, central heating heat supply net, central air conditioning air pipe, municipal works pipeline. The elbow of the heat preservation pipe is formed by tightly combining an outer sleeve, a polyurethane foam heat preservation layer and an inner working steel pipe. The heat preservation pipe elbow is mainly used for steering the heat preservation straight pipe, is generally matched with the heat preservation straight pipe for use, provides compensation function in a heat preservation engineering pipeline, and enables the elbow part to have enough heat preservation performance. For example, chinese utility model with application number CN201821214781.4 discloses a plastic-sheathed steel heat preservation piping elbow, including the steel pipe, the lateral wall welding of steel pipe has the supporting shoe, and the outer end fixed mounting of supporting shoe has the high density polyethylene protective layer, and the lateral wall fixed mounting of supporting shoe has the polystyrene foam board, and fixed mounting has the polyurethane heat preservation between polystyrene foam board and the steel pipe, and fixed mounting has the glass cotton between polystyrene foam board and the high density polyethylene protective layer.

The outer sleeve pipe adopts the integral type structure in current heat preservation elbow, and when the temperature was lower winter, the outer sleeve pipe buckling part was easy to shrink and is produced the fold, and the fold department can produce the internal stress, and long-time internal stress can lead to the outer sleeve pipe fracture. Relative sliding can be produced between heat preservation layer and the work steel pipe in current heat preservation piping elbow, and then produces the clearance, influences the thermal insulation performance. In addition, the joint of the existing heat preservation pipe elbow and the heat preservation straight pipe is butted by adopting a binder, and the performance of the binder is reduced after the binder is heated, so that the sealing performance of the joint of the heat preservation pipe elbow and the heat preservation straight pipe is reduced, heat loss is caused, and the heat preservation performance is reduced.

Disclosure of Invention

Technical problem to be solved

The invention provides a heating heat-preservation pipe elbow, aiming at solving the following problems in the prior art: (1) when the temperature of the integrated heat-preservation pipe elbow is low, the bending part of the outer sleeve is easy to shrink to generate wrinkles, the wrinkles generate internal stress, and the outer sleeve is cracked due to the internal stress for a long time; (2) relative sliding can be generated between the heat-insulating layer in the heat-insulating pipe elbow and the working steel pipe, so that a gap is generated, and the heat-insulating performance is influenced; (3) the joint of the heat-insulating pipe elbow and the heat-insulating straight pipe is butted by adopting the adhesive, and the performance of the adhesive is reduced after the adhesive is heated, so that the tightness of the joint of the heat-insulating pipe elbow and the heat-insulating straight pipe is reduced, heat loss is caused, and the heat-insulating performance is reduced.

(II) technical scheme

The invention provides a heating heat-preservation pipe elbow which comprises an outer sleeve, a heat-preservation layer and a steel pipe from inside to outside, wherein a sealing mechanism connected with a heat-preservation straight pipe is arranged at the end part of the heating heat-preservation pipe elbow. The outer sleeve comprises an upper outer sleeve and a lower outer sleeve, and the upper outer sleeve and the lower outer sleeve are connected through a plug and a socket. The upper outer sleeve consists of more than two upper outer sleeves, the lower outer sleeve consists of lower outer sleeves, and the number of the lower outer sleeves is the same as that of the upper outer sleeves. The outer surface of the adjacent upper outer ring and the outer surface of the adjacent lower outer ring are connected to form a circle of groove with the same depth. The recess fit has the hoop, and the surface of hoop and the surface parallel and level of last outer lantern ring and outer lantern ring down, and the internal surface of hoop is fixed to be provided with along hoop length direction's first mushroom and detains. A first buckle groove matched with the first mushroom buckle is formed in the groove. Through the cooperation of first mushroom knot and first catching groove, link together adjacent upper outer lantern ring and adjacent lower outer lantern ring, improved the sealing performance of outer tube to the heat preservation.

the heat preservation comprises last heat preservation and lower heat preservation, and the faying face of going up heat preservation and lower heat preservation forms spacing strip and the first spacing groove of mutually supporting. The limiting strips and the first limiting grooves limit radial sliding between the upper heat-insulating layer and the lower heat-insulating layer in a matching manner, and the sealing performance of the heat-insulating layer to the steel pipe is improved. The inner surfaces of the upper outer collar and the lower outer collar and the outer surfaces of the upper heat-insulating layer and the lower heat-insulating layer form a first limiting ring and a second limiting groove which are matched with each other. The cooperation of the first limiting ring and the second limiting groove limits the axial sliding between the upper heat-insulating layer and the outer sleeve, and between the lower heat-insulating layer and the outer sleeve, and improves the sealing performance of the outer sleeve to the heat-insulating layer.

As a preferred technical scheme of the invention, the outer surface of the steel pipe is welded with three groups of upper fins and three groups of lower fins, the upper fins are embedded in the upper heat-insulating layer, and the lower fins are embedded in the lower heat-insulating layer. The limiting effect of the upper fins and the lower fins limits the relative sliding between the upper heat-insulating layer and the outer surface of the steel pipe, the lower heat-insulating layer and the outer surface of the steel pipe, and gaps between the upper heat-insulating layer and the outer surface of the steel pipe and between the lower heat-insulating layer and the outer surface of the steel pipe are avoided, so that the heat-insulating performance is improved.

As a preferable technical scheme of the invention, the end part of the steel pipe is fixedly connected with the straight steel pipe of the heat preservation straight pipe through a flange disc.

As a preferred technical scheme of the invention, the sealing mechanism comprises a second limiting ring protruding from the end parts of the upper insulating layer and the lower insulating layer, the end part of the second limiting ring is fixedly connected with a third limiting ring, the outer diameters of the second limiting ring and the third limiting ring are the same, and the inner diameter of the second limiting ring is larger than that of the third limiting ring. The end parts of the heat-insulating layer and the lower heat-insulating layer, the second limiting ring and the third limiting ring enclose a first cavity with an opening on the side surface. The sealing mechanism further comprises a fourth limiting ring formed by the end part of the straight pipe heat-insulating layer in a protruding mode, the end part of the fourth limiting ring is fixedly connected with a fifth limiting ring, the outer diameters of the fourth limiting ring and the fifth limiting ring are the same, and the inner diameter of the fourth limiting ring is larger than that of the fifth limiting ring. The end part of the straight pipe heat-insulating layer, the fourth limiting ring and the fifth limiting ring enclose a second cavity with an opening on the side surface. The fourth limiting ring and the fifth limiting ring are matched with the first cavity. The second limiting ring and the third limiting ring are matched with the second cavity. Through the limiting effect of the third limiting ring and the fifth limiting ring, the axial sliding between the heat-insulating layer and the straight pipe heat-insulating layer is limited, the situation that the surface of the steel pipe is not covered by heat-insulating materials is avoided, and the heat-insulating performance is improved.

As a preferred technical solution of the present invention, iron sheets are fixedly disposed on inner sides of the second limiting ring and the fourth limiting ring, and magnetic sheets are fixedly disposed on inner sides of the third limiting ring and the fifth limiting ring corresponding to positions of the iron sheets. The iron sheet and the magnetic sheet are adsorbed together, so that relative sliding between the fourth limiting ring and the first cavity and between the second limiting ring and the second cavity and between the third limiting ring and the second cavity are avoided, a gap is further avoided between the heat preservation layer and the straight pipe heat preservation layer, and the heat preservation performance of the joint of the heating heat preservation pipe elbow and the heat preservation straight pipe is improved.

As a preferred technical solution of the present invention, an elastic sealing strip abutting against the groove is fixedly adhered to an edge of the hoop strip. The one end fixedly connected with second mushroom of hoop is buckled, and the other end of hoop is seted up and is buckled the complex second catching groove with the second mushroom, and the second mushroom is buckled and has been realized hoop to the fastening of outer lantern ring on adjacent and adjacent outer lantern ring down with the cooperation in second catching groove.

As a preferred technical scheme of the invention, the outer surfaces of the upper outer collar and the lower outer collar are fixedly connected with a sixth limiting ring, the inner surface of the sixth limiting ring is fixedly connected with third mushroom buckles which are arranged at equal intervals, and the outer surface of the straight tube outer collar is provided with a third buckle groove matched with the third mushroom buckles. The cooperation of the third mushroom buckles and the third buckle grooves ensures that the upper outer sleeve ring, the lower outer sleeve ring and the straight pipe outer sleeve ring cannot slide axially and radially, ensures that the heat-insulating layer cannot be exposed in the air, and further improves the heat-insulating performance.

(III) advantageous effects

The invention has the following beneficial effects:

(1) The outer sleeve of the heating and heat-insulating pipe elbow adopts a split structure, so that wrinkles generated when the cooling temperature of the outer sleeve is reduced are reduced, the internal stress of the outer sleeve is reduced, and the outer sleeve is prevented from cracking; due to the limiting effect of the fins, the heat insulation layer in the heating heat insulation pipe elbow cannot slide relative to the working steel pipe, so that the generation of gaps is avoided, and the heat insulation performance is improved; the end part of the heating heat-preservation pipe elbow is provided with a sealing mechanism connected with the heat-preservation straight pipe, so that heat loss is avoided, and the heat preservation performance is further improved.

(2) The sealing mechanism of the heating insulation pipe elbow ensures that the heat insulation layer of the insulation pipe elbow and the heat insulation layer of the straight pipe cannot slide axially through the matching of the fourth limiting ring and the fifth limiting ring with the first cavity and the matching of the second limiting ring and the third limiting ring with the second cavity, improves the sealing property of the joint of the heating insulation pipe elbow and the heat insulation straight pipe, and improves the heat insulation performance.

(3) The outer sleeve of the heating and heat-insulating pipe elbow consists of a plurality of outer sleeves, and adjacent outer sleeves are fixedly connected through a hoop strip. On one hand, the structure of the plurality of outer sleeves reduces the wrinkles generated when the cooling temperature of the outer sleeve is reduced, reduces the internal stress of the outer sleeve and avoids the outer sleeve from cracking; on the other hand, compare integral type outer collar, the structure of a plurality of outer collars is difficult to take place deformation, ensures that can not produce the clearance between outer collar and the heat preservation, and then has improved thermal insulation performance.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a top view of the internal structure of one embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along line A-A in accordance with an embodiment of the present invention;

FIG. 3 is a schematic illustration of the deployed strake according to an embodiment of the present invention;

Fig. 4 is an enlarged schematic view of the point B in one embodiment of the present invention.

In the figure: 1-outer sleeve, 101-upper outer sleeve, 102-lower outer sleeve, 103-plug, 104-socket, 105-upper outer sleeve, 106-lower outer sleeve, 107-groove, 108-hoop strip, 109-first mushroom fastener, 110-first fastening groove, 111-first limiting ring, 112-second mushroom fastener, 113-second fastening groove, 114-sixth limiting ring, 115-third mushroom fastener, 2-heat preservation layer, 201-upper heat preservation layer, 202-lower heat preservation layer, 203-limiting strip, 204-first limiting groove, 205-second limiting groove, 3-steel pipe, 301-upper fin, 302-lower fin, 4-sealing mechanism, 401-second limiting ring, 402-third limiting ring, 403-first cavity, 5-straight steel pipe, 6-flange plate, 7-straight pipe insulating layer, 701-fourth limiting ring, 702-fifth limiting ring, 703-second cavity, 8-iron sheet, 9-magnetic sheet, 10-elastic sealing strip, 11-straight pipe outer sleeve ring and 1101-third buckling groove.

Detailed Description

the embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.

As shown in fig. 1 to 4, the present embodiment provides a heating insulation pipe elbow, which comprises an outer sleeve 1, an insulation layer 2 and a steel pipe 3 from inside to outside, wherein a sealing mechanism 4 connected with an insulation straight pipe is arranged at an end of the heating insulation pipe elbow. The outer sleeve 1 comprises an upper outer sleeve 101 and a lower outer sleeve 102, and the upper outer sleeve 101 and the lower outer sleeve 102 are connected through a plug 103 and a socket 104. The upper outer sleeve 101 is composed of more than two upper outer collars 105, the lower outer sleeve 102 is composed of lower outer collars 106, and the number of the lower outer collars 106 is the same as that of the upper outer collars 105. A groove 107 with the same depth is formed at the joint of the outer surfaces of the adjacent upper outer ring 105 and the adjacent lower outer ring 106. A hoop strip 108 is fitted in the groove 107, the outer surface of the hoop strip 108 is flush with the outer surfaces of the upper outer collar 105 and the lower outer collar 106, and a first mushroom button 109 is fixedly arranged on the inner surface of the hoop strip 108 along the length direction of the hoop strip 108. A first snap groove 110 is formed in the recess 107 for cooperation with a first mushroom snap 109. The first mushroom buckles 109 are matched with the first buckle grooves 110 to connect the adjacent upper outer sleeve 105 and the adjacent lower outer sleeve 106 together, so that the sealing performance of the outer sleeve 1 on the heat insulation layer 2 is improved.

The insulating layer 2 is composed of an upper insulating layer 201 and a lower insulating layer 202, and a limiting strip 203 and a first limiting groove 204 which are matched with each other are formed on the combination surface of the upper insulating layer 201 and the lower insulating layer 202. The limiting strips 203 and the first limiting grooves 204 are matched with each other to limit the radial sliding between the upper heat-insulating layer 201 and the lower heat-insulating layer 202, so that the sealing performance of the heat-insulating layer 2 to the steel pipe 3 is improved. The inner surfaces of the upper outer collar 105 and the lower outer collar 106 and the outer surfaces of the upper insulating layer 201 and the lower insulating layer 202 form a first limiting ring 111 and a second limiting groove 205 which are matched with each other. The cooperation of the first limiting ring 111 and the second limiting groove 205 limits the axial sliding between the upper insulating layer 201 and the lower insulating layer 202 and the outer sleeve 1, and improves the sealing performance of the outer sleeve 1 to the insulating layer 2.

In this embodiment, three sets of upper fins 301 and three sets of lower fins 302 are welded on the outer surface of the steel pipe 3, the upper fins 301 are embedded in the upper insulating layer 201, and the lower fins 302 are embedded in the lower insulating layer 202. The limiting effect of the upper fins 301 and the lower fins 302 limits the relative sliding between the upper insulating layer 201 and the outer surface of the steel pipe 3 and between the lower insulating layer 202 and the outer surface of the steel pipe 3, prevents the upper insulating layer 201 and the lower insulating layer 202 from generating gaps with the outer surface of the steel pipe 3, and further improves the insulating performance.

in this embodiment, the end of the steel pipe 3 is fixedly connected to the straight steel pipe 5 of the straight heat-insulating pipe by a flange 6.

In this embodiment, the sealing mechanism 4 includes a second limiting ring 401 protruding from the end portions of the upper insulating layer 201 and the lower insulating layer 202, the end portion of the second limiting ring 401 is fixedly connected to a third limiting ring 402, the outer diameters of the second limiting ring 401 and the third limiting ring 402 are the same, and the inner diameter of the second limiting ring 401 is larger than the inner diameter of the third limiting ring 402. The end portions of the insulating layer 201 and the lower insulating layer 202, and the second limiting ring 401 and the third limiting ring 402 enclose a first cavity 403 with an opening on the side surface. The sealing mechanism 4 further comprises a fourth limiting ring 701 formed by protruding the end part of the straight pipe insulating layer 7, the end part of the fourth limiting ring 701 is fixedly connected with a fifth limiting ring 702, the outer diameters of the fourth limiting ring 701 and the fifth limiting ring 702 are the same, and the inner diameter of the fourth limiting ring 701 is larger than that of the fifth limiting ring 702. The end of the straight pipe insulating layer 7, the fourth limiting ring 701 and the fifth limiting ring 702 enclose a second cavity 703 with an opening on the side. The fourth stop collar 701 and the fifth stop collar 702 cooperate with the first cavity 403. The second stop collar 401 and the third stop collar 402 cooperate with the second cavity 703. Through the limiting effect between the third limiting ring 402 and the fifth limiting ring 702, the axial sliding between the heat-insulating layer 2 and the straight pipe heat-insulating layer 7 is limited, the situation that the surface of the steel pipe 3 is not covered by heat-insulating materials is avoided, and the heat-insulating performance is improved.

In this embodiment, iron sheets 8 are fixedly disposed on the inner sides of the second limiting ring 401 and the fourth limiting ring 701, and magnetic sheets 9 are fixedly disposed on the inner sides of the third limiting ring 402 and the fifth limiting ring 702 corresponding to the positions of the iron sheets 8.

In this embodiment, the elastic sealing tape 10 abutting on the groove 107 is fixedly adhered to the edge of the band 108. One end of the hoop strip 108 is fixedly connected with a second mushroom buckle 112, the other end of the hoop strip 108 is provided with a second buckle groove 113 matched with the second mushroom buckle 112, and the matching of the second mushroom buckle 112 and the second buckle groove 113 realizes the fastening of the hoop strip 108 to the adjacent upper outer collar 105 and the adjacent lower outer collar 106.

In this embodiment, the outer surfaces of the upper outer collar 105 and the lower outer collar 106 are fixedly connected with a sixth limiting ring 114, the inner surface of the sixth limiting ring 114 is fixedly connected with third mushroom fasteners 115 arranged at equal intervals, and the outer surface of the straight tube outer collar 11 is provided with a third fastening groove 1101 matched with the third mushroom fasteners 115.

The principle of the embodiment for realizing the beneficial effects is as follows:

(1) The outer sleeve 1 of the heating insulation pipe elbow of the embodiment is composed of a plurality of outer sleeves, and adjacent outer sleeves are fixedly connected through the hoop strips 108. On one hand, the structure of the plurality of outer sleeves reduces the wrinkles generated when the cooling temperature of the outer sleeve 1 is reduced, reduces the internal stress of the outer sleeve 1, and avoids the cracking of the outer sleeve 1; on the other hand, the structure of a plurality of outer collars 1 is difficult to deform, so that gaps are not generated between the outer collars 1 and the heat preservation layer 2, and the heat preservation performance is improved.

(2) In this embodiment, the first mushroom fastener 109 is engaged with the first fastening groove 110 to connect the adjacent upper outer collar 105 and the adjacent lower outer collar 106, so as to improve the sealing performance of the outer sleeve 1 to the insulating layer 2. The limiting strips 203 and the first limiting grooves 204 limit the radial sliding between the upper insulating layer 201 and the lower insulating layer 202 in cooperation, and the sealing performance of the insulating layer 2 to the steel pipe 3 is improved in the embodiment. In this embodiment, the first limiting ring 111 and the second limiting groove 205 are matched to limit the axial sliding between the upper insulating layer 201 and the outer sleeve 1, and the lower insulating layer 202 and the outer sleeve 1, so as to improve the sealing performance of the outer sleeve 1 to the insulating layer 2. In the embodiment, the third limiting ring 402 and the fifth limiting ring 702 limit each other, so that the axial sliding between the heat-insulating layer 2 and the straight-pipe heat-insulating layer 7 is limited, the situation that the surface of the steel pipe 3 is not covered by heat-insulating materials is avoided, and the heat-insulating performance is improved. This embodiment is through adsorbing iron sheet 8 and magnetic sheet 9 together, has ensured between fourth spacing ring 701 and fifth spacing ring 702 and first cavity 403 to and can not produce relative slip between second spacing ring 401 and third spacing ring 402 and the second cavity 703, further ensured not to produce the clearance between heat preservation 2 and the straight tube heat preservation 7, thereby improved the thermal insulation performance of heating heat preservation elbow and heat preservation straight tube junction. In this embodiment, the cooperation of the third mushroom fastener 115 and the third fastener slot 1101 ensures that the upper outer collar 105, the lower outer collar 106 and the straight pipe outer collar 11 do not slide axially or radially, and ensures that the insulating layer 2 is not directly exposed in the air, thereby further improving the insulating performance.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.