CN219263415U - Double-wall corrugated pipe and extruder head - Google Patents

Abstract

The utility model relates to the technical field of plastic pipes, in particular to a double-wall corrugated pipe, which comprises an inner wall and an outer wall, wherein the outer wall comprises wave crests and wave troughs, the wave crests and the wave troughs are axially and alternately connected along the outer wall, the connection parts of the wave crests and the wave troughs are integrated with the inner wall, peak ribs are arranged on the wave crests along the circumferential direction of the wave crests, and the wave troughs outwards arch to form annular reinforcing ribs. The ring stiffness of the double-wall corrugated pipe can be increased through the arrangement of the peak ribs and the arched wave troughs; the utility model also relates to an extrusion machine head for processing the double-wall corrugated pipe, which comprises an outer mold, a middle mold and an inner mold which are arranged from outside to inside, wherein an outer wall flow channel is formed by surrounding between the outer mold and the middle mold, an inner wall flow channel is formed by surrounding between the middle mold and the inner mold, a plurality of spiral air channels are arranged in the middle mold along the middle mold in an axial penetrating way, an outlet of each spiral air channel is positioned between an outlet of the outer wall flow channel and an outlet of the inner wall flow channel, the arrangement of each spiral air channel can reduce the influence of moisture in compressed air on the adhesion of the inner wall and the outer wall, and the quality of the double-wall corrugated pipe is ensured.

Description

Double-wall corrugated pipe and extruder head

Technical Field

The utility model relates to the technical field of plastic pipes, in particular to a double-wall corrugated pipe and an extruder head.

Background

The corrugated pipe is a novel light pipe with high-density polyethylene as a raw material, has the characteristics of light weight, high pressure resistance, good toughness, low manufacturing cost and the like compared with the traditional pipes such as cast iron pipes, galvanized steel pipes and the like, is widely applied to drainage and pollution discharge engineering, is not suitable for buried construction environments because the corrugated pipe wall of a single-layer pipe wall is thin and easy to deform, gradually produces a double-wall corrugated pipe with relatively good performance through continuous perfection, but still easily deforms due to external force extrusion in the buried or transportation process, has low ring stiffness and cannot meet market requirements.

Disclosure of Invention

The utility model aims to provide a double-wall corrugated pipe which is convenient to process and high in ring rigidity.

To achieve the purpose, the utility model adopts the following technical scheme:

the double-wall corrugated pipe comprises an inner wall and an outer wall, wherein the outer wall is sleeved outside the inner wall, the outer wall comprises a wave crest and a wave trough, the wave crest and the wave trough are axially and alternately connected with each other, the junction of the wave crest and the wave trough is integrated with the inner wall, peak ribs sunken in the inner wall direction are circumferentially arranged on the wave crest along the wave crest, the wave trough is arched in the direction away from the inner wall to form a circumferential reinforcing rib, and the height of the peak ribs is higher than that of the wave trough.

Optionally, a plurality of peak ribs are arranged on each peak at intervals along the axial direction of the outer wall, the distances between adjacent peak ribs are the same, and the peak ribs are in a closed ring shape.

Optionally, the peaks are circumferentially arranged as polygons.

The utility model also aims to provide an extruder head for processing the double-wall corrugated pipe, which adopts the following technical scheme: the extruder head comprises an outer die, an intermediate die and an inner die which are arranged from outside to inside, wherein an outer wall flow channel is formed by enclosing between the outer die and the intermediate die, an inner wall flow channel is formed by enclosing between the intermediate die and the inner die, a plurality of spiral air channels are axially and penetratingly arranged in the intermediate die along the intermediate die, and an outlet of each spiral air channel is positioned between an outlet of the outer wall flow channel and an outlet of the inner wall flow channel.

Optionally, the machine head comprises a flow dividing section, a reducing section and an outlet section, wherein the flow dividing section comprises an outer spiral sleeve, an outer spiral body and an inner spiral body which are sequentially arranged from outside to inside, the reducing section comprises an outer taper sleeve, an outer core die and an inner core die which are sequentially arranged from outside to inside, the outlet section comprises an outer die sleeve, an outer die body, an inner die sleeve and an inner die body which are sequentially arranged from outside to inside, the outer spiral sleeve, the outer taper sleeve and the outer die sleeve jointly form the outer die, the outer spiral body, the outer core die body, the outer die body and the inner die sleeve jointly form the middle die, and the inner spiral body, the inner core die and the inner die body jointly form the inner die; the outer die sleeve and the outer die body enclose to form an outlet of the outer wall flow channel, and the inner die sleeve and the inner die body enclose to form an outlet of the inner wall flow channel.

Optionally, the outer mandrel includes outer cone and the mandrel body that sets up from outside to inside, spiral air flue by outer cone with the mandrel body encloses and closes and form, the tail end of core die body protrusion in the tail end setting of outer cone, outer die body with interior die sleeve all overlaps to be established on the core die body, outer die body with form the air flue export between the interior die sleeve.

Optionally, the head end face of the outer die body is abutted to the tail end face of the outer cone and enclosed with the tail end face of the outer cone to form a closed annular air cavity, the air cavity is communicated with the spiral air passage, and the air cavity is connected with the air passage outlet through a connecting air passage penetrating through the outer die body along the axial direction of the outer die body.

Optionally, an axial distance between the outer die body and the inner die sleeve is adjustable.

Optionally, the split section is provided with a first heating assembly, and the reducing section is provided with a second heating assembly for continuously heating the molten material.

Optionally, an annular buffer groove is circumferentially arranged on the inner die body.

The beneficial effects of the utility model are as follows: according to the double-wall corrugated pipe provided by the utility model, the peak ribs are arranged on the wave crests, so that the load range born by the wave crests can be increased, the structural strength of the wave crests is enhanced, the wave troughs are arched, the stress born by the positions of the inner walls corresponding to the wave troughs can be dispersed, the strength between the wave troughs and the adjacent wave crests is further enhanced, and the peak ribs are mutually matched with the wave troughs, so that the double-wall corrugated pipe has the advantages of high ring stiffness, difficult deformation and bending; the extrusion machine head provided by the utility model converts the existing direct current air passage into the spiral air passage, so that the length of the whole air passage can be increased, moisture in compressed air stays on the wall of the spiral air passage, the adhesion of the outer wall and the inner wall is avoided, and meanwhile, the spiral air passage can uniformly transfer the heat of the outer mold to the inner mold, so that the inner wall is uniformly heated, and the plasticizing effect of the inner wall is improved.

Drawings

FIG. 1 is a schematic perspective view of a double-wall bellows in an embodiment of the present utility model;

FIG. 2 is a front view of a double wall bellows in an embodiment of the present utility model;

FIG. 3 is a side view of a double wall bellows in an embodiment of the present utility model;

FIG. 4 is a cross-sectional view of a double wall bellows in an embodiment of the present utility model;

FIG. 5 is an enlarged schematic view at A in FIG. 4;

FIG. 6 is a schematic perspective view of an extruder head in an embodiment of the present utility model;

FIG. 7 is a side view of an extruder head in an embodiment of the present utility model;

FIG. 8 is a left side view of an extruder head in an embodiment of the present utility model;

FIG. 9 is a cross-sectional view of an extruder head in the practice of the present utility model;

FIG. 10 is an enlarged schematic view at B in FIG. 9;

fig. 11 is an enlarged schematic view at C in fig. 9.

In the figure: 100. a double-wall bellows; 110. an outer wall; 111. a peak; 111a, peak ribs; 112. a trough; 120. an inner wall; 200. an extruder head; 210. an outer mold; 211. an outer spiral sleeve; 212. an outer cone sleeve; 213. an outer die sleeve; 220. middle mold; 221. an outer screw; 222. an outer core mold; 222a, an outer cone; 222b, a core die body; 223. an outer die body; 224. an inner die sleeve; 230. an inner mold; 231. an inner screw; 232. an inner core mold; 233. an inner mouth mold body; 233a, a buffer recess; 240. a cooling water jacket; 241. sizing sleeve; 242. a cooling jacket; 243. a water inlet pipe; 244. a water return pipe; I. an outer wall flow passage; J. an inner wall flow passage; K. a spiral airway; k1, an air passage outlet; l, cooling cavity; m, an air cavity; n, connecting the air passage.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

The embodiment provides a double-wall corrugated pipe, is mainly applied to drainage, blowdown engineering, and present double-wall corrugated pipe ring rigidity is low, anti sinking ability is poor, receives easy deformation and buckling after external pressure in the use, can cause the damage of double-wall corrugated pipe even when serious, is difficult to adapt to drainage, blowdown engineering's construction environment, and the double-wall corrugated pipe in this embodiment has solved above-mentioned problem through improving the crest and the trough shape of its outer wall.

Referring to fig. 1-5, the double-wall corrugated pipe 100 according to the present embodiment includes an outer wall 110 and an inner wall 120, the outer wall 110 is sleeved outside the inner wall 120, wherein the inner wall 120 is a hollow circular tube, the outer wall 110 includes a peak 111 and a trough 112, the width of the peak 111 is greater than that of the trough 112, the peak 111 and the trough 112 are axially connected with each other along the outer wall 110, the junction of the peak 111 and the trough 112 is integrated with the inner wall 120, a peak rib 111a recessed toward the inner wall 120 is circumferentially arranged on the peak 111, the trough 112 is arched toward a direction far away from the inner wall 120 to form a circumferential reinforcing rib, and the height of the peak rib 111a is higher than that of the trough 112.

In this embodiment, the peak rib 111a and the arched trough 112 disposed on the peak 111 can both play a role of a reinforcing rib, where the peak rib 111a increases the load range that the peak 111 can bear, and the trough 112 can disperse the stress that the position of the inner wall 120 corresponding to the trough 112 receives, further enhancing the strength between the trough 112 and the adjacent peak 111, and the peak rib 111a and the trough 112 are mutually matched, so that the method has the advantages of high ring stiffness, difficult deformation and bending, and can realize plastic substitution of steel.

Alternatively, a plurality of peak ribs 111a may be disposed on each peak 111 along the axial direction of the outer wall 110 at intervals, the spacing between adjacent peak ribs 111a is the same, the peak ribs 111a are in a closed ring shape, so as to realize circumferential reinforcement of the entire peak 111, specifically, the longitudinal section of the peak rib 111a is in a U shape, and the width of the peak rib is smaller than the width of each portion of the peak 111 divided by the peak rib 111 a.

Referring to fig. 3, the wave crest 111 is circumferentially arranged to be polygonal, specifically regular polygon, and can be supported by the double-wall corrugated pipe 100 during construction, so that good stability of the corrugated pipe can be maintained, and no pipe pillow is needed.

The double-wall corrugated pipe 100 may be made of high-density polyethylene, and the general forming process is as follows: the plastic raw material is firstly plasticized by a plastic extruder and is converted into a molten state, the molten state material passes through an extruder head 200, an extruding mechanism extrudes two pipe blanks with different calibers in the shape of a pipe, the pipe blank with large caliber is an outer wall 110 of the pipe, the pipe blank with small aperture is an inner wall 120 of the pipe, after the pipe blank enters a corrugated pipe forming die through blow molding, the outer wall 110 is tightly attached to an inner cavity of the forming die through the combined action of compressed air and vacuum, and meanwhile, the inner wall 120 is stretched and shaped along the outer peripheral surface of a sizing sleeve 241 (a cooling water jacket 240) and is partially bonded with the outer wall 110 (the bonding part of the double-wall corrugated pipe 100 in the embodiment refers to the joint of a crest 111 and a trough 112), and finally the double-wall corrugated pipe 100 in the embodiment is formed.

When the extruder head 200 is used for conveying gas between the outer wall 110 and the inner wall 120, a direct current air passage axially penetrating the middle die 220 is usually formed in the middle die 220, and the gas is compressed air, so that moisture is inevitably contained in the compressed air, and if the direct current air passage is adopted, the air passage is too short, so that the moisture enters between the outer wall 110 and the inner wall 120, the adhesion between the outer wall 110 and the inner wall 120 is affected, layering is caused, and the plasticizing effect of the double-wall corrugated pipe 100 is affected.

To this end, referring to fig. 6-11, the present embodiment further proposes an extruder head 200 for processing the above-mentioned double-wall corrugated tube 100, which includes an outer mold 210, an intermediate mold 220 and an inner mold 230 disposed from the outside to the inside, wherein an outer wall flow channel I is formed by enclosing between the outer mold 210 and the intermediate mold 220, an inner wall flow channel J is formed by enclosing between the intermediate mold 220 and the inner mold 230, a plurality of spiral air channels K are disposed in the intermediate mold 220 along the axial direction thereof, and an outlet of the spiral air channel K is disposed between an outlet of the outer wall flow channel I and an outlet of the inner wall flow channel J for supplying compressed air to the outer wall 110.

Compared with the existing direct current air flue, the spiral air flue K in the embodiment can increase the length of the whole air flue, so that moisture in compressed air stays on the wall of the spiral air flue K, the adhesion of the outer wall 110 and the inner wall 120 is avoided, meanwhile, the spiral air flue K can enable heat of the outer mold 210 to be evenly transferred to the inner mold 230, the inner wall 120 is further evenly heated, and the plasticizing effect of the inner wall 120 is improved.

Referring to fig. 6-10, the extruder head 200 according to the present embodiment adopts a split structure, so as to facilitate assembly and later maintenance, and specifically includes a split section, a reducing section and an outlet section that are sequentially connected from the head end to the tail end along the axial direction of the extruder head 200, where the split section is used for feeding materials to an outer wall runner I and an inner wall runner J, and includes an outer spiral sleeve 211, an outer spiral 221 and an inner spiral 231 that are sequentially disposed from the outside to the inside, the head end surface of the outer spiral sleeve 211 is connected with the head end flange of the outer spiral 221, the head end of the inner spiral 231 is connected with the head end surface flange of the outer spiral 221, and an outer wall runner I inlet that is communicated with the outer wall runner I and an inner wall runner J inlet that is communicated with the inner wall runner J are radially and separately disposed on the outer spiral sleeve 211, so as to avoid a difference in material speed entering the outer wall runner I and the inner wall runner J, and the outer wall runner I inlet and the inner wall runner J are disposed on the same axis and horizontally, which affects the forming effect of the double wall bellows 100; the reducing section is used for shrinking the diameters of the outer wall 110 and the inner wall 120 and comprises an outer taper sleeve 212, an outer core mould 222 and an inner core mould 232 which are sequentially arranged from outside to inside, wherein the head end of the outer taper sleeve 212 is fixedly connected with the tail end of the outer spiral sleeve 211, the head end of the outer core mould 222 is fixedly connected with the tail end of the outer spiral body 221, and the inner core mould 232 is fixedly connected with the tail end of the inner spiral body 231; the outlet section comprises an outer die sleeve 213, an outer die body 223, an inner die sleeve 224 and an inner die body 233 which are arranged from outside to inside, wherein the outer die sleeve 213 is sleeved at the tail end of the outer cone sleeve 212, the outer die body 223 and the inner die sleeve 224 are sleeved at the tail end of the outer core mould 222, and the inner die body 233 is sleeved at the tail end of the inner core mould 232.

The outer screw sleeve 211, the outer cone sleeve 212 and the outer die sleeve 213 together form an outer die 210, the outer screw body 221, the outer core die 222, the outer die body 223 and the inner die sleeve 224 together form an inner die 220, and the inner screw body 231, the inner die 232 and the inner die body 233 together form an inner die 230; the outer die sleeve 213 and the outer die body 223 enclose a trumpet-shaped outer wall flow channel I outlet, and the inner die sleeve 224 and the inner die body 233 enclose a trumpet-shaped inner wall flow channel J outlet.

Still further, the outer core mold 222 further includes an outer cone 222a and a core mold 222b disposed from the outside to the inside, the tail end of the core mold 222b protrudes out of the tail end of the outer cone 222a, the outer die body 223 and the inner die sleeve 224 are both sleeved on the core mold 222b, an air passage outlet K1 is formed between the outer die body 223 and the inner die sleeve 224, and a multi-strip-shaped uniform spiral air passage K is formed between the outer cone 222a and the core mold 222b in a surrounding manner, so that the spiral air passage K can be cleaned regularly and conveniently, and the ventilation effect is prevented from being influenced. Specifically, the outer diameter of the inner peripheral layer is the same as the inner diameter of the outer peripheral layer, the inner wall 120 of the outer peripheral layer and/or the inner wall 120 of the inner peripheral layer are provided with spiral grooves, when the outer peripheral layer is sleeved on the inner peripheral layer, the spiral grooves are surrounded to form a spiral air passage K, and the inlet of the spiral air passage K and the outlet of the spiral air passage K are uniformly distributed circumferentially at two axial ends of the outer core mold 222 respectively so as to ensure that compressed air uniformly enters between the outer wall 110 and the inner wall 120. The spiral air passage K communicates with an air passage inlet that axially penetrates the outer spiral along the outer spiral body 221.

The head end face of the outer die body 223 sleeved on the core die body 222b is abutted to the tail end face of the outer cone 222a and is enclosed with the tail end face of the outer cone 222a to form a closed annular air cavity M, the annular air cavity M is communicated with the spiral air channel K, the annular air cavity M is connected with the air channel outlet K1 by penetrating through the connecting air channel N of the outer die body 223 along the axial direction of the outer die body 223, compressed air flows into the annular air cavity M after flowing out of the spiral air channel K, and then flows to the air channel outlet K1 from the air cavity M through the connecting air channel N, so that smooth circulation of the air is realized, the connection difficulty of the outer die body 223 and the outer cone 222a can be reduced by the aid of the arrangement of the air cavity M, and smooth flowing of compressed air in the spiral air channel K to the air channel outlet K1 is guaranteed.

The axial distance between the outer die body 223 and the inner die sleeve 224, i.e., the size of the air passage outlet K1, is adjustable. Specifically, the inner die sleeve 224 is screwed with the core die body 222b, and the size of the air passage outlet K1 can be adjusted by adjusting the position of the inner die sleeve 224 on the core die body 222b, so that the air pressure of the flowing compressed air can be adjusted.

Similarly, the axial distance between the outer die sleeve 213 and the outer die body 223, and between the inner die sleeve 224 and the inner die body 233 may be adjusted to achieve adjustment of the wall thickness of the outer wall 110 and the wall thickness of the inner wall 120, respectively. Specifically, the outer die sleeve 213 is screwed with the outer cone sleeve 212, and the inner die body 233 is screwed with the inner die 232.

The outer wall runner Inlet and the outer wall runner Inlet, the inner wall runner Inlet and the inner wall runner Inlet are far apart from each other in the axial direction, that is, the distance from the inlet to the outlet of the molten material is long, the molten material is easy to cool and become thick in the material flowing process, the fluidity is poor, the extrusion time of the double-wall corrugated pipe 100 is prolonged, the requirement of high-speed production cannot be met, and therefore, the split section and the reducing section of the extruder head 200 are respectively provided with a first heating component and a second heating component for continuously heating the molten material.

In this embodiment, the first heating element may be a heating ring, and is embedded in the outer spiral body 221 along the axial direction of the outer spiral body 221; the second heating element is the heliciform resistance wire, and the periphery of outer taper sleeve 212 is provided with the helicla flute that is used for holding the resistance wire, and the resistance wire embedding helicla flute is interior to be realized heating inner wall 120 and outer wall 110 simultaneously, and the setting of spiral air flue K is for direct current air flue simultaneously, can make the better heat of receiving outer wall runner I transmission of inner wall runner J, guarantees that inner wall 120 is heated evenly.

In the prior art, it was found that after the extruder head 200 is stopped, part of the molten raw materials in the outer wall runner I and the inner wall runner J will remain, after the extruder head is restarted and heated, the residual molten raw materials are often accompanied with gas release, so that the gas pressure in the runner is increased, especially in the inner wall runner J, if the gas pressure in the inner wall runner J is too large, the molten materials in the inner wall runner J will be directly ejected, and a potential safety hazard is generated, so that the annular buffer groove 233a is circumferentially arranged in the inner port die body 233, and a plurality of circles can be specifically arranged along the circumferential direction of the inner port die body 233, so that the size of the outlet of the inner wall runner J is increased by phase change, and when the gas flows to the outlet of the inner wall runner J, the gas will diffuse into the buffer groove 233a, so that the gas pressure is reduced, and the ejection of the molten materials is avoided.

Referring to fig. 7 and 9-11, the extruder head 200 further includes a cooling water jacket 240, which is used for cooling and shaping the formed double-wall corrugated pipe 100, the cooling water jacket 240 is connected with the tail end of the inner core die 232, the cooling water jacket 240 includes a sizing pipe and a cooling pipe which is connected in the sizing pipe in a sealing manner, a plurality of spiral cooling grooves are formed in the outer surface of the cooling pipe, the outer diameter of the cooling pipe is the same as the inner diameter of the sizing pipe, and the flow of water in a cooling cavity L formed by the cooling grooves and the inner wall 120 of the sizing pipe in a surrounding manner can be realized. The cooling water jacket 240 forms a closed circulation system with the water supply device through a water inlet pipe 243 and a water return pipe 244, wherein the water return pipe 244 axially penetrates through the whole inner mold 230 along the inner mold 230 and extends into the cooling water jacket 240 to be communicated with the head end of the cooling cavity L, the water inlet pipe 243 is sleeved in the water return pipe 244, the water inlet pipe 243 axially penetrates out of the water return pipe 244 along the water return pipe 244 to be communicated with the tail end of the cooling cavity L, and the inlet of the water inlet pipe 243 and the outlet of the water return pipe 244 are arranged on the same side.

The cooling water for cooling the double-wall corrugated pipe 100 sequentially flows through the diversion section, the reducing section and the outlet section along the water inlet pipe 243 to enter the cooling cavity L for cooling the double-wall corrugated pipe 100, and in the cooling process, the tail end of the double-wall corrugated pipe 100 is gradually cooled to the head end of the double-wall corrugated pipe 100 so as to realize gradual connection of temperature change and avoid the influence of the cooling water jacket 240 on the shaping effect of the outlet section. The cooling water absorbs heat carried by the double-wall corrugated pipe 100, then flows back into the water return pipe 244, and flows out through the outlet of the return pipe, thereby completing one cycle.

It will be appreciated that the heat insulating layer is coated on the inner surface and/or the outer surface of the water inlet pipe 243, so that heat exchange between the water inlet pipe 243 and the water return pipe 244 can be reduced, and the cooling effect can be ensured. Likewise, the heat insulation layer is coated on the inner surface and/or the outer surface of the water return pipe 244, so that heat exchange between the water return pipe 244 and the inner wall runner J can be avoided, and the plasticizing effect is ensured.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the utility model. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims (10)

1. Double-wall bellows, characterized by comprising:

an inner wall (120);

outer wall (110), outer wall (110) cover is established outside inner wall (120), outer wall (110) are including crest (111) and trough (112), crest (111) with trough (112) are followed outer wall (110) axial alternate connection, crest (111) with junction and inner wall (120) of trough (112) are assembled into an organic wholely, follow on crest (111) circumference be provided with to peak rib (111 a) that inner wall (120) direction is sunken, trough (112) are to keeping away from the direction arch of inner wall (120) forms the hoop strengthening rib, peak rib (111 a) highly be higher than the height of trough (112).

2. A double-walled bellows according to claim 1, wherein a plurality of the crest ribs (111 a) are provided on each crest (111) at an axial interval along the outer wall (110), the pitch between adjacent crest ribs (111 a) being the same, the crest ribs (111 a) being in the shape of a closed ring.

3. A double-walled bellows according to claim 1, characterized in that the peaks (111) are circumferentially arranged as polygons.

4. Extruder head for processing the double-wall corrugated pipe according to any one of claims 1-3, characterized by comprising an outer mold (210), an intermediate mold (220) and an inner mold (230) which are arranged from outside to inside, wherein an outer wall flow channel (I) is formed by enclosing between the outer mold (210) and the intermediate mold (220), an inner wall flow channel (J) is formed by enclosing between the intermediate mold (220) and the inner mold (230), a plurality of spiral air channels (K) are axially and penetratingly arranged in the intermediate mold (220) along the intermediate mold (220), and the outlets of the spiral air channels (K) are positioned between the outlets of the outer wall (110) flow channel and the outlets of the inner wall (120) flow channel.

5. The extruder head according to claim 4, comprising a split section, a reducing section and an outlet section, wherein the split section comprises an outer spiral sleeve (211), an outer spiral body (221) and an inner spiral body (231) which are sequentially arranged from outside to inside, the reducing section comprises an outer cone sleeve (212), an outer core die (222) and an inner core die (232) which are sequentially arranged from outside to inside, the outlet section comprises an outer die sleeve (213), an outer die body (223), an inner die sleeve (224) and an inner die body (233) which are sequentially arranged from outside to inside, the outer spiral sleeve (211), the outer cone sleeve (212) and the outer die sleeve (213) jointly form the outer die (210), the outer spiral body (221), the outer core die (222), the outer die body (223) and the inner die sleeve (224) jointly form the inner die (220), and the inner die (232) and the inner die body (233) jointly form the inner die (230); the outer die sleeve (213) and the outer die body (223) are enclosed to form an outlet of the outer wall flow channel (I), and the inner die sleeve (224) and the inner die body (233) are enclosed to form an outlet of the inner wall flow channel (J).

6. The extruder head of claim 5 wherein the outer mandrel (222) comprises an outer cone (222 a) and a mandrel body (222 b) disposed from the outside to the inside, the spiral air channel (K) is formed by enclosing the outer cone (222 a) and the mandrel body (222 b), the tail end of the mandrel body (222 b) protrudes out of the tail end of the outer cone (222 a), the outer die body (223) and the inner die sleeve (224) are both sleeved on the mandrel body (222 b), and an air channel outlet (K1) is formed between the outer die body (223) and the inner die sleeve (224).

7. The extruder head according to claim 6, wherein the head end face of the outer die body (223) abuts against the tail end face of the outer cone body (222 a) and encloses with the tail end face of the outer cone body (222 a) to form a closed annular air cavity (M), the air cavity (M) is communicated with the spiral air channel (K), and the air cavity (M) is connected with the air channel outlet (K1) through a connecting air channel (N) axially penetrating the outer die body (223) along the outer die body (223).

8. The extruder head according to claim 6, wherein the axial distance between the outer die body (223) and the inner die sleeve (224) is adjustable.

9. The extruder head of claim 5 wherein the diverter stage is provided with a first heating assembly and the reducing stage is provided with a second heating assembly for continuously heating the molten material.

10. The extruder head according to claim 5, wherein the inner die body (233) is circumferentially provided with an annular buffer groove (233 a).

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