CN110789080A

CN110789080A - Production device, production method and application of connecting pipe fitting of plastic composite pipe

Info

Publication number: CN110789080A
Application number: CN201911100908.9A
Authority: CN
Inventors: 王晓峰; 孔智勇; 胡召元
Original assignee: Shandong Donghong Pipe Industry Co Ltd
Current assignee: Shandong Donghong Pipe Industry Co Ltd
Priority date: 2019-11-12
Filing date: 2019-11-12
Publication date: 2020-02-14
Anticipated expiration: 2039-11-12
Also published as: CN110789080B

Abstract

The invention relates to the field of plastic connecting pipe fitting production devices, in particular to a connecting pipe fitting production device of a plastic composite pipe, a production method and application. The device structure does: the hydraulic forming device comprises a vertical hydraulic device and a forming die, and the forming die for forming the connecting pipe fitting is arranged in the hydraulic device; the extrusion device comprises: an extruder, an extruder screw, an extruder nozzle; the extruder screw rod sets up in the barrel of extruder, and heating device has been laid to the barrel outside, and the extruder nozzle sets up at the barrel head, and the storage device structure is: the material storage cylinder is communicated with a nozzle of the extruder; a heating device is laid outside the storage cylinder; the storage cylinder motor is arranged in the storage cylinder, and the other port of the storage cylinder is communicated with the forming die; the accumulator motor is used for driving the molten raw material to be injected into the forming die. The production device designed by the invention can solve the defect that the conventional horizontal injection molding machine cannot produce large-caliber and high-pressure all-plastic connecting pipe fittings.

Description

Production device, production method and application of connecting pipe fitting of plastic composite pipe

Technical Field

The invention relates to the field of plastic connecting pipe fitting production devices, in particular to a connecting pipe fitting production device of a plastic composite pipe, a production method and application.

Background

The information disclosed in this background of the invention is only for enhancement of understanding of the general background of the invention and is not necessarily to be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

The steel wire mesh framework plastic composite pipe is favored by the pipeline engineering industry due to the superior performances of corrosion resistance, high pressure bearing, light weight and the like; the maximum pressure-bearing grade of the pipe in the known related standard can reach 7.0MPa, wherein the pressure-bearing capacity of the steel wire mesh framework plastic composite pipe with the caliber of DN500 or more can reach 2.5MPa nominal pressure; the existing connection mode of DN500 and above caliber steel wire mesh framework plastic composite pipes comprises flanging double-sealing connection and electric melting pipe connection.

The flanging double-seal connection needs to use steel structural members, iron flanges and fastening bolts, and because iron products cannot get rid of the corrosion prevention problem under the buried condition, along with the extension of the pipeline running time, the probability of leakage hidden danger at the joint due to corrosion is increased year by year, the maintenance difficulty is higher, and great influence is generated on daily production and life. The plastic electrofusion connecting piece has the advantages of acid and alkali corrosion resistance, but the thickness of the connecting piece must be increased for obtaining higher bearing capacity because the tensile strength of the polyethylene plastic is low; in the existing market, DN500 and above large-caliber plastic electric melting connecting pieces are limited by internal defects of thick-wall plastics in the injection molding process, such as internal shrinkage air holes, low bonding strength at a joint line and the like, and the pressure-bearing grade of a product is always limited by 1.6MPa and below nominal pressure; when the pipeline connection with the nominal pressure of 1.6MPa or above occurs, the plastic electric melting connecting piece can not ensure the requirement of safe operation of the pipeline, so that the application and popularization of the steel wire pipe with large caliber and high pressure and full plastic connection are greatly limited.

In order to solve the overall plastic connection problem of the steel wire mesh framework plastic composite pipe, a framework reinforced composite connecting piece already exists in the market, but is limited by injection molding production equipment, technical process, post-processing equipment and other factors, and the maximum caliber of the existing framework reinforced composite connecting piece can only reach DN500 caliber and the maximum pressure grade of 1.6 MPa; part of small products can reach 3.5MPa pressure level; when the required pipelines are connected by steel wire mesh framework plastic composite pipes with models of more than DN500, no proper connection mode is available.

Disclosure of Invention

In view of the above problems, the present invention aims to provide a device for producing a connecting pipe fitting of a plastic composite pipe, a production method and applications thereof. Compared with the conventional horizontal injection molding machine, the production device designed by the invention has the advantages that the working pressure is increased by more than two times; the defect that a conventional horizontal injection molding machine cannot produce connecting pipe fittings of steel wire mesh framework plastic composite pipes with the models of more than DN500 can be effectively overcome.

One of the objects of the present invention: provides a production device for connecting pipe fittings of plastic composite pipes.

The second object of the present invention is: provides a production method of a connecting pipe fitting of a plastic composite pipe.

The third object of the present invention is: provides the application of the production device of the connecting pipe fitting of the plastic composite pipe.

In order to achieve the purpose, the invention adopts the following technical means:

the invention discloses a production device for a connecting pipe fitting of a plastic composite pipe, which comprises a hydraulic forming device, an extrusion device and a storage device, wherein the hydraulic forming device is used for forming a plastic composite pipe; the hydraulic forming device comprises a vertical hydraulic device and a forming die, wherein the forming die for forming the connecting pipe fitting is arranged in the hydraulic device; the extrusion apparatus comprises: an extruder, an extruder screw, and an extruder nozzle; the extruder screw is arranged in a machine barrel of the extruder, a heating device is laid outside the machine barrel, and the extruder nozzle is arranged at the head of the machine barrel. The storage device comprises a storage cylinder and a storage cylinder motor, the storage cylinder is communicated with the nozzle of the extruder, and the storage cylinder is provided with a material containing space larger than the barrel of the extruder; a heating device is laid outside the storage cylinder; a hydraulic rod of the storage cylinder motor is arranged in the storage cylinder, and the other port of the storage cylinder is communicated with the forming die; the storage cylinder motor is used for driving the melting raw materials to be injected into the forming die.

Secondly, the invention discloses a method for preparing a connecting pipe fitting of a plastic composite pipe by adopting the connecting pipe fitting production device, which comprises the following steps:

(1) conveying the dried granular raw materials into a cylinder of an extruder, converting the raw materials into molten fluid through physical actions such as heating, shearing, plasticizing and the like in the cylinder, and injecting the molten fluid into a material storage cylinder through an extruder nozzle under the action of an extruder screw;

(2) the molten state fluid is insulated and secondarily plasticized in the storage cylinder and is injected into the forming die under the action of a motor of the storage cylinder, the steel mesh framework which is installed in the forming die in advance is wrapped in the molten state fluid after being injected into the die to form the plastic composite pipe, and therefore the steel mesh framework and the molten plastic are integrally combined, and the connecting pipe fitting of the plastic composite pipe with the required structure is obtained.

Finally, the invention discloses a production device of a connecting pipe fitting of the plastic composite pipe and application of a product prepared by the production method in the field of pipeline engineering.

One of the characteristics of the production device for the connecting pipe fitting of the plastic composite pipe designed by the invention is as follows: through with mechanisms optimal design such as hydraulic means, the extruder, the storage cylinder, the pressure injection former after the assembly has bigger nominal effort, can reach 30MPa operating pressure, promote more than the twice for conventional horizontal injection molding machine operating pressure, this is because the molding equipment is provided power by the motor, direct action is on hydraulic motor, the hydraulic motor output is connected with the upper die base of hydraulic press, during operation realizes fluid input and output by motor drive motor, and then drive hydraulic press upper die base and realize reciprocating motion from top to bottom along four post slide rails, this kind of effort is more direct, energy transmission loss is few, drive mechanism is simple and convenient. The horizontal injection molding machine needs to act together through a plurality of mechanisms such as a motor, a hydraulic pump, gear pair meshing, a hinge mechanism and the like, the loss in the energy transfer process is large, and the structure of the horizontal equipment is limited, so that under the same motor power, the effective acting force actually generated by the horizontal equipment relative to the vertical equipment is small, and the energy transmission efficiency is low. Therefore, the invention can overcome the defects of large-diameter connecting pipes which cannot be produced by a conventional horizontal injection molding machine when adopting a vertical design, for example, when producing products with large diameter, heavy weight and thicker wall thickness, the gas existing between a mold and a melting material can be discharged to a great extent by large working pressure, the product density is increased, and the quality hidden troubles of air bubbles, shrinkage air holes, low bonding line strength and the like in the products are avoided.

The connecting pipe fitting production device of the plastic composite pipe designed by the invention is characterized in that: according to the invention, the material storage cylinder is arranged between the extruder and the hydraulic forming device, only the screw rod part of the traditional standard injection molding equipment is provided with a melt storage space, and the screw rod melts raw materials and then performs injection molding to fill a mold, so as to obtain a product with a required structure; however, when the equipment is used for producing products with large caliber and large mass, due to the restriction of melt space, the machine barrel and the screw of the extruder must be lengthened, so that the production and manufacturing difficulty and the maintenance cost of the equipment are increased. The extruder and the storage cylinder part of the invention both have melt storage capacity, and the storage cylinder has a larger material containing space relative to the extruder cylinder, which is irreplaceable when producing pipes with large caliber and heavy weight; therefore, the design enables the production device of the invention to cover more product types in product coverage, and significantly invests the comprehensive cost of the equipment.

The connecting pipe fitting production device of the plastic composite pipe designed by the invention is further characterized in that: the storage vat designed by the invention has the heating and heat-preserving effects, and has the technical advantage that the molten plastic has better processing performance through heat preservation and secondary plasticization of the storage vat on the molten plastic. The reason is that when the melt mass flow rate of the granular raw materials is smaller (less than or equal to 0.2g/10min) or the granular raw materials are composite modified materials with higher tensile strength (more than or equal to 30MPa), the plasticizing effect of the screw on the materials is reduced; in addition, when a product with higher quality is produced, the more molten materials are required by single injection, and the whole plasticizing capacity of the equipment must be improved to ensure higher production efficiency of the product; but the plasticizing capacity of the extruder is directly influenced by the rotating speed of the screw and the material characteristics, and the plasticizing effect on the granular raw materials can be sacrificed at high rotating speed; the requirement of rapid continuous production cannot be met only by virtue of the plasticizing action of a single screw, and at the moment, the reheating and secondary plasticizing capacities of the storage cylinder are required, so that the optimal processing performance of raw materials is ensured.

The production device for the connecting pipe fitting of the plastic composite pipe designed by the invention is characterized in that: because the production device of the invention drives the die to move up and down by the hydraulic motor, only the steel mesh framework in the die cavity generates axial force in the process of melt adhesive injection molding, and the deformation of the mesh framework in the diameter direction can not be caused; the horizontal injection molding machine acts in parallel, radial compression can be caused to the mesh framework in the glue melting injection molding process, and the out-of-roundness and the size of the mesh framework are influenced.

The fifth characteristic of the connecting pipe fitting production device of the plastic composite pipe designed by the invention is that: the position of the steel mesh framework is limited through the supporting rod at the end part of the plastic mold core, and the supporting nails distributed on the outer circular surface of the steel mesh framework are fixed with the mold cavity, so that the freedom degree of the mesh framework in each direction in the mold is fixed, and the stability of continuous production of products in the injection molding process is ensured.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention provides a production device and a production method with a brand-new structure, which are particularly suitable for producing a large-caliber steel mesh framework reinforced composite pipe fitting, wherein the mold locking force of a standard injection molding machine is generally lower than 15MPa, and when a product with larger volume and larger mass is produced, the defects of low strength, low density and the like of an inner air hole and a joint line of the product are easily caused by abnormal mold expansion due to insufficient mold locking force. Compared with the conventional horizontal injection molding machine, the production device designed by the invention has the advantages that the working pressure is increased by more than two times, the requirement on the stability of mold locking force can be ensured when products with larger volume and larger mass are produced, the influence on the product density, the product quality and the appearance caused by the reduction of mold pressing due to the hidden trouble of mold expansion is avoided, and the defect that the conventional horizontal injection molding machine cannot produce connecting pipe fittings of steel wire mesh framework plastic composite pipes with the models of more than DN500 is well overcome.

(2) In the production of large-diameter pipe fittings in the market at present, a required blank is generally obtained in a mode of extruding PE pipes, but the mode has the disadvantages of complicated production and debugging, high rejection rate and high comprehensive product cost; the product is of a full-plastic non-composite structure, and in the products with the same pressure-bearing grade, the consumption of raw materials of the products with the non-composite structure is high and is not matched with the development trend of energy conservation and consumption reduction; the connecting pipe prepared by the invention is a composite pipe of a steel mesh framework and plastic, and can well overcome the defects.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

Fig. 1 is a schematic structural view of a connecting pipe production apparatus for a plastic composite pipe according to a first embodiment of the present invention.

Fig. 2 is a plan view of a connecting pipe production apparatus for plastic composite pipes according to a first embodiment of the present invention.

Fig. 3 is a schematic structural view of an extruder nozzle according to a fifth embodiment of the present invention.

Fig. 4 is a schematic structural view of a molding die according to an eleventh embodiment of the present invention.

Fig. 5 is a schematic structural view of a mold core according to eleventh and twelfth embodiments of the present invention.

Fig. 6 is a schematic structural view of steel mesh frameworks according to eleventh and twelfth embodiments of the invention.

Fig. 7 is a schematic structural view of a steel mesh skeleton according to a thirteenth embodiment of the present invention.

Fig. 8 is a schematic structural diagram of a composite pipe manufactured according to a fifteenth embodiment of the present invention.

The designations in the above figures represent respectively: 1-a hydraulic press; 2-an upper die holder; 3-a lower die holder; 4-a slide rail; 5-a hydraulic press motor; 6-an extruder; 7-extruder screw; 8-extruder nozzle; 9-a material storage cylinder; 10-a hydraulic motor of the storage cylinder; 11-an upper mold cavity; 12-lower die cavity; 13-a mould core; 14-injection molding holes; 15-support rods; 16-steel mesh skeleton; 17-support nail.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

For convenience of description, the words "up", "down", "left" and "right" in the present invention, if any, merely indicate that the directions of movement are consistent with those of the drawings, and do not limit the structure, but merely facilitate the description of the invention and simplify the description, rather than indicate or imply that the referenced device or element needs to have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

The terms "mounted", "connected", "fixed", and the like in the present invention are to be understood in a broad sense, and may be, for example, fixedly connected, detachably connected, or integrated; the two components can be connected mechanically or electrically, directly or indirectly through an intermediate medium, or connected internally or in an interaction relationship, and the terms used in the present invention should be understood as having specific meanings to those skilled in the art.

As described above, some existing skeleton-reinforced composite connectors in the market are limited by injection molding equipment, technical processes, post-processing equipment, and other factors, and cannot meet the requirement for preparing connecting pipes of steel wire mesh skeleton plastic composite pipes with pipelines of models greater than DN 500. Therefore, the invention provides a production device and a production method for a connecting pipe fitting of a plastic composite pipe; the invention will now be further described with reference to the drawings and detailed description.

First embodimentReferring to fig. 1 and 2, there is illustrated a production apparatus for connecting pipe members of plastic composite pipes designed according to the present invention, comprising: the device comprises a hydraulic forming device, an extrusion device and a material storage device;

the hydraulic forming device comprises a vertical hydraulic device and a forming die, wherein the forming die for forming the connecting pipe fitting is arranged in the hydraulic device; specifically, the vertical hydraulic device includes: the hydraulic forming device comprises a hydraulic machine 1, an upper die base 2, a lower die base 3, a slide rail 4 and a hydraulic machine motor 5, wherein all the components are assembled and distributed in an upper-lower layer mode, and the lower die base 3 is located at the bottommost part of the whole hydraulic forming device, supports the whole device and is fixed on the ground; the sliding rail 4 is fixed at the top of the lower die base 3, and the sliding rail 4 is vertical to the lower die base and connects the lower die base and the upper die base into a whole; the hydraulic motor is arranged on the top of the upper die holder 2. The upper die base can move up and down along the slide rail under the action of the hydraulic motor, and then the plastic forming die is driven to realize the actions of die assembly, die opening, pressure application and the like.

The extrusion apparatus comprises: an extruder 6, an extruder screw 7, and an extruder nozzle 8; the extruder screw 7 is arranged in a machine barrel of the extruder 6, and a heating device is laid outside the machine barrel to ensure the requirement of the granular raw material plasticizing process on the heating temperature; the extruder nozzle 8 is arranged at the head of the machine barrel.

The storage device comprises a storage cylinder 9 and a storage cylinder hydraulic motor 10, the storage cylinder 9 is communicated with the extruder nozzle 8, and a heating device is laid outside the storage cylinder 9; the material storage cylinder 9 is a material containing mechanism which is provided with a material containing space larger than that of the cylinder of the extruder; generally, the extruder is responsible only for converting the solid particulate material into molten plastic, which is then transported by screw extrusion to an accumulator for storage.

A hydraulic rod of the storage cylinder hydraulic motor 10 is arranged in one end port of the storage cylinder 9, and the other end port of the storage cylinder 9 is communicated with the forming die; the accumulator hydraulic motor 10 is used to drive the molten feedstock to be injected into the forming mold.

It is understood that on the basis of the first embodiment, the following technical solutions including but not limited to the following may be derived to solve different technical problems and achieve different purposes of the invention, and specific examples are as follows:

second embodimentBolt holes are uniformly distributed in the circumferential direction on the end face of one side of the storage cylinder body, and the hydraulic motor is connected with the storage cylinder body in a sealing mode through high-strength bolts; one end of a hydraulic rod in the hydraulic motor is in interference sealing connection with the inner circular surface of the storage cylinder body and extends into the storage cylinder body, so that the coaxiality of the storage cylinder body and the hydraulic motor is consistent, and the relative heights of the storage cylinder body and the hydraulic motor are consistent; meanwhile, in order to avoid vibration during the operation of the motor, the motor and the storage cylinder body are both positioned at the upper part of the storage cylinder base and supported by the storage cylinder base. In the operation process, the forward rotation and the reverse rotation of the motor are used for realizing oil inlet and oil return of the liquid medium, and finally, the hydraulic rod in the motor is driven to realize forward and backward movement.

Third embodimentReferring to fig. 1 and 2, the hydraulic machine 1 is a four-column hydraulic machine, the slide rails 4 are four cylindrical slide rails 4, and the circular direction of the four cylindrical slide rails 4 is vertically fixed on the top of the lower die holder 3On the upper part.

It should be noted that, for such a hydraulic device of vertical design, the technical advantages are that; under the action of a motor of the hydraulic machine, the upper die base can move up and down in the vertical direction and obtain required direct acting force; generally, when composite pipe fittings with large caliber, thick wall and heavy weight are produced, the hydraulic machine designed in the mode can provide a mold locking force not less than 30MPa, so that the upper cavity surface and the lower cavity surface of the mold can be always firmly attached in the high-pressure injection molding process of products with large caliber and thick wall, the production and processing abnormalities such as material leakage and pressure release are not generated, and the defects of shrinkage holes, low bonding line strength and the like which are easy to occur in the production of products with large caliber and thick wall are thoroughly solved; the standard horizontal injection molding equipment can only meet the nominal mold locking force of 15MPa at most, and the defects of low welding strength of products, incomplete internal exhaust, low product density and the like caused by insufficient mold locking force are easily caused; therefore, the production device designed by the embodiment has the advantages that standard horizontal injection molding equipment cannot produce large-caliber and thick-wall products.

Fourth embodimentThe machine barrel of the extruder 6 is of a long tubular structure with a certain wall thickness, and a ceramic heating ring is radiated on the outer surface of the machine barrel to ensure that heat is transmitted to the whole machine barrel to melt the raw material (solid granular plastic) after power-on heating, so that the requirement of a granular raw material plasticizing process on the heating temperature is met.

Fifth embodimentThe top of the extruder 6 is also provided with a storage barrel with a heating and drying function, namely a drying barrel, and raw materials are conveyed into the extruder barrel from the bottom of the drying barrel after being dried. The moisture in the raw materials is removed by heating, so that the better appearance of the plastic product is ensured, and the occurrence of abnormal air holes in the product is reduced.

Sixth embodimentReferring to fig. 3, the extruder nozzle 8 is a convex spherical nozzle, and the curvature of the spherical arc of the nozzle is R20; one side of the storage cylinder body is processed with an inwards concave conical inner hole, the storage cylinder 9 is vertically arranged relative to the extruder 6, the conical inner hole and a spherical nozzle of the extruder can be tightly attached together, and concave-convex assembly is realizedThe extruded feedstock enters the accumulator through this passage and is stored.

Further, in some embodiments, the spherical arc curvature of the nozzle 8 is also designed as R23. The technical advantage of designing the extruder nozzle 8 as a convex spherical nozzle is: when the extruder moves forwards and backwards along the bottom rail groove and is matched with the storage cylinder again, the spherical nozzle design can assist in correcting the position deviation in the matching process of the extruder and the storage cylinder, facilitates the coaxiality control between the extruder and the conical inner hole of the storage cylinder, improves the matching precision and the sealing effect, and ensures that the pressure reduction and the material waste caused by flash in the high-pressure injection process can be avoided.

Further, in some embodiments, the nozzle 8 is threadably engaged with the barrel of the extruder 6 by conical pipe threads.

Seventh embodimentThe ceramic heating rings are arranged outside the cylinder body of the storage cylinder 9 and serve as heating devices, so that the melting raw materials are always in a melt state and have better processing performance, and processed products have better mechanical performance.

Eighth embodimentAnd the connecting pipe fitting production device also comprises a suction machine which is used for sucking the raw materials and conveying the raw materials to the drying material cylinder of the extruder.

Ninth embodimentThe extruder 6 is a single-screw extruder, the extruder screw 7 is a cylindrical shaft body with a spiral groove cut on the outer surface, and the length-diameter ratio of the extruder screw 7 is 35; higher aspect ratios can achieve better material plasticizing effects.

Further, in some embodiments, the extruder screw 7 is a conical shaft with a spiral groove cut on the outer surface, and the screw length-diameter ratio of the extruder screw 7 is greater than 35. At present, the length-diameter ratio of the screw of the standard horizontal injection molding machine of domestic manufacturers is generally not more than 25; the larger the length-diameter ratio of the screw rod is, the higher the plasticizing efficiency of the equipment to the granular raw materials and the faster the production efficiency of the product can be ensured.

Tenth embodimentThe extruder is characterized in that a rail groove is formed in the bottom of the extruder, and the extruder can move along the direction of the slide rail as required after the rail groove and the ground slide rail are assembled together.

Eleventh embodimentThe surfaces of the upper die holder 2 and the lower die holder 3 are respectively provided with a T-shaped groove structure so as to be convenient for mounting a forming die, an upper die cavity and a lower die cavity of the forming die are respectively detachably fixed in the upper die holder 2 and the lower die holder 3, and the upper die cavity moves up and down along with the upper die holder 2 under the action of a hydraulic motor, so that the actions of die assembly, die opening, pressure application and the like are realized.

Twelfth embodimentReferring to fig. 4 and 5, the forming mold is a split design, and includes an upper mold cavity 11, a lower mold cavity 12 and a mold core 13, where the upper mold cavity 11 and the lower mold cavity 12 have a structural contour consistent with an outer circular surface of a product; the die core 11 is of an integral and cylindrical structure and has a structural outline consistent with the inner circle surface of a product, the die core 11 is fixed at the center of the lower die cavity 12, the die core 11 is perpendicular to the joint surface of the upper die and the lower die, the lower die cavity 12 is provided with an injection hole 14, the injection hole 14 is communicated with the storage cylinder 9, and when the connecting pipe fitting is prepared, under the action of the hydraulic motor 10 of the storage cylinder, a molten raw material is driven to enter a forming die through the injection hole 14 to form a composite connecting pipe fitting with a steel mesh framework 16 (refer to fig. 6).

When the die is used, the upper die cavity 11 is arranged in a T-shaped groove of the upper die base 2 of the four-column hydraulic machine, the lower die cavity 12 is arranged in a T-shaped groove of the lower die base 3, and after the die is installed, the upper die base 2 moves up and down along a slide rail 4 of the hydraulic machine under the driving of a motor 5 of the hydraulic machine, so that the die closing and opening functions of the upper die cavity 11 and the lower die cavity 12 are realized.

Thirteenth embodimentReferring to fig. 5, the bottom of the core is provided with steel support rods 15 which are circumferentially and uniformly distributed and fixed in the lower mold cavity 12; correspondingly, steel support rods 15 which are circumferentially and uniformly distributed are also arranged on the upper die cavity 11, and the support rods 15 on the upper die cavity 11 and the lower die cavity 12 are in a one-to-one correspondence and symmetrical distribution mode. When in use, the steel mesh framework 16 (refer to figure 6) is sleeved into the mold core 13, the support rods in the lower mold cavity 12 support the mesh-reinforced framework sleeve, the central axis of the mold core 13 is kept to be coincident with the central axis of the steel mesh framework 16, and the support rods 15 in the upper mold cavity 11 just prop against the steel holes after the upper mold cavity 11 is closedAnd the end face of the mesh framework 16 is arranged, so that the steel mesh framework 16 is restrained between the support rods 15 of the upper die cavity 11 and the lower die cavity 12, and the upper die cavity 11 and the lower die cavity 12 are just matched.

It should be noted that, the support rods 15 are disposed on the upper and lower mold cavities, which is another key technology of the present invention, and aims to ensure that the positions of the steel mesh skeleton 16 are always consistent when being placed in the mold cavity, prevent the steel mesh skeleton from shifting due to high pressure during the plastic injection process, and improve the stability of the product during the injection molding process. In addition, in the design, the sum of the axial length of the steel mesh framework and the extension length of the upper die supporting rod and the lower die supporting rod is consistent with the height of a cavity in the die, and the position of the mesh framework in the die cavity is reliably fixed through the combined action of the axial fixing of the upper die supporting rod and the lower die supporting rod and the radial supporting nail.

Further, in some embodiments, the support rods may have an outer diameter of 12mm to 16mm, and are circumferentially spaced apart by 60 degrees.

In addition, the lengths of the support rods of the moulds of different models are different due to the integral length of the product and the length difference of the steel mesh framework 16; when the mold normally works, the joint part of the mold core and the mold cavity is in interference fit, so that the molten plastic is prevented from overflowing in the high-pressure glue injection process.

Fourteenth embodimentReferring to fig. 7, the steel mesh skeleton 16 has support nails 17 of equal length fixed to its outer surface, which are circumferentially spaced at 60 °. The support nails are matched with the inner circular surface of the die cavity, so that the position fixity of the mesh reinforced framework in the die is ensured; through the combined action of bracing piece and supporting nail, with the position accuracy of steel mesh skeleton in the mould fixed, guarantee the product stability of moulding plastics in-process.

Further, in some embodiments, three rings of supporting nails 17 are fixed on the outer surface of the steel mesh skeleton 16, each ring of supporting nails is circumferentially distributed at intervals of 90 °, and the interval between the adjacent supporting nails 17 is 100 mm.

In other embodiments, the interval between the upper and lower adjacent support pins 17 is also set to 80 mm; or at other suitable spacings; the length of the supporting nail can be reasonably selected according to the length of the prepared pipe body.

Fifteenth embodimentIn addition, the invention also adopts the device to prepare the composite connecting pipe fitting, and the steps are as follows:

before production, a forming die is installed in a four-column hydraulic machine, an upper die cavity 11 of the forming die is installed in a T-shaped groove of an upper die base 2 of the four-column hydraulic machine, and a lower die cavity 12 of the forming die is installed in a T-shaped groove of a lower die base 3 of the four-column hydraulic machine.

After the installation is finished, the upper die base 2 moves up and down along the vertical direction of the four-column slide rail 4 of the hydraulic machine under the driving of a motor 5 of the hydraulic machine, so that the die closing and opening functions of the forming die are realized; after the die is installed and debugged, the steel mesh framework is placed into a forming die along a die core 13, and the relative position of the mesh framework in a die cavity is fixed through a support rod 15; and finally, moving the upper die cavity 11 of the forming die downwards under the action of the hydraulic motor 5 until the upper die cavity and the lower die cavity 12 are in a fit state.

Then conveying the solid granular plastic to a drying cylinder of the extruder through a suction machine, and conveying the dried solid granular plastic to the interior of a machine barrel of the extruder from the bottom of the cylinder; after entering the extruder barrel, the granular plastic is electrified for the ceramic heating ring outside the extruder barrel, is converted into a molten state fluid (namely molten plastic) through physical actions such as heating, plasticizing and shearing of an extruder screw in the extruder barrel, and then is injected into a storage tank 9 with a larger material containing space through an extruder nozzle 8 under the action of an extruder screw 7; the molten plastic has better processing performance through the heat preservation and the secondary plasticization of the storage cylinder; finally, the molten plastic is injected into the mold cavity through the storage cylinder along the injection port 14 on the lower mold cavity 12, so that the steel mesh framework 16 and the molten plastic are integrally combined, and the plastic reinforced composite pipe fitting with the required structure is obtained, as shown in fig. 8, the plastic reinforced composite pipe fitting is a composite pipe fitting with the mesh reinforced framework coated inside and having a certain thickness. The composite pipe fittings with different size parameters are prepared by the method, the performance parameters are shown in table 1, and the composite pipe fittings completely meet the all-plastic connection requirements of large-caliber high-pressure composite pipelines with the diameters of more than 500mm through tests. The connecting piece mainly plays a role in radial pressure bearing in the fluid transportation of the buried plastic pipeline; therefore, the steel mesh framework with higher tensile yield strength is implanted into the plastic connecting piece, so that the application of plastic raw materials can be reduced, the integral bearing capacity of the connecting piece can be obviously improved, and the manufacturing cost of a product is reduced (the cost of the plastic is about 5 times of that of steel); meanwhile, on the premise of the same pressure-bearing capacity of the product, the composite connecting piece with the mesh reinforced framework is smaller in size, lighter in weight and simpler and more convenient to construct and install.

TABLE 1

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.

Claims

1. A production device for connecting pipe fittings of plastic composite pipes is characterized by comprising a hydraulic forming device, an extruding device and a material storing device;

the hydraulic forming device comprises a vertical hydraulic device and a forming die, and the forming die for forming the connecting pipe fitting is arranged in the hydraulic device;

the extrusion apparatus comprises: an extruder, an extruder screw, an extruder nozzle; the extruder screw is arranged in a machine barrel of the extruder, a heating device is laid outside the machine barrel, and the extruder nozzle is arranged at the head of the machine barrel;

the storage device comprises: the storage cylinder is communicated with the nozzle of the extruder and is provided with a material containing space larger than the cylinder of the extruder; a heating device is laid outside the storage cylinder; a hydraulic rod of the storage cylinder motor is arranged in the storage cylinder, and the other port of the storage cylinder is communicated with the forming die; the storage cylinder motor is used for driving the melting raw materials to be injected into the forming die.

2. A connecting pipe member producing apparatus for plastic composite pipe as defined in claim 1, wherein said extruder has a long tubular structure with a ceramic heating ring radiated on the outer surface thereof;

preferably, the cylinder bodies of the storage cylinders are externally provided with ceramic heating rings as heating devices.

3. The production device of the connecting pipe fitting of the plastic composite pipe as claimed in claim 1, wherein the top of the extruder is further provided with a storage drum with a heating and drying function;

or the connecting pipe fitting production device also comprises a suction machine which is used for sucking the raw materials and conveying the raw materials to the drying material cylinder of the extruder;

or the hydraulic machine is a four-column hydraulic machine, the slide rails are four cylindrical slide rails, and the circular direction of the four cylindrical slide rails is vertically fixed on the top of the lower die base; preferably, the accumulator motor is a hydraulic motor.

4. A connecting pipe production apparatus for plastic composite pipes according to claim 1, wherein the extruder is provided at a bottom thereof with rail grooves, and the extruder is movable in a direction of the rail grooves after the rail grooves are assembled with the ground rail;

preferably, the extruder is a single-screw extruder, the extruder screw is a cylindrical shaft body with a spiral groove cut on the outer surface, and the length-diameter ratio of the extruder screw 7 is preferably more than or equal to 35.

5. A connecting pipe member production apparatus for a plastic composite pipe according to any one of claims 1 to 4, wherein said extruder nozzle is a convex spherical nozzle;

preferably, the spherical arc curvature of the nozzle is R20-R23;

preferably, one side of the storage cylinder body is provided with an inwards concave conical inner hole, the storage cylinder is vertically arranged relative to the extruder, and the conical inner hole and a spherical nozzle of the extruder can be tightly attached together to realize concave-convex assembly;

preferably, the nozzle is screwed to the barrel of the extruder by means of a conical tube screw.

6. A connecting pipe fitting production apparatus for plastic composite pipes according to any one of claims 1 to 4, wherein the molding die is a split design, two dies, an upper die and a lower die, and comprises an upper die cavity, a lower die cavity and a die core, and the upper die cavity and the lower die cavity have a structural contour consistent with the outer circular surface of the product; the mold core is of an integral and cylindrical structure and has a structural profile consistent with the inner circular surface of a product, the mold core is fixed at the center of the lower mold cavity and is vertical to the combined surface of the upper mold and the lower mold, the lower mold cavity is provided with an injection molding hole, and the injection molding hole is communicated with the storage cylinder;

preferably, the surfaces of the upper die holder and the lower die holder are provided with groove structures, when the die is used, the upper die cavity is arranged in a T-shaped groove of the upper die holder of the four-column hydraulic press, and the lower die cavity is arranged in a T-shaped groove of the lower die holder.

7. A connecting tube production apparatus for plastic composite tubes as claimed in claim 6, wherein the core has steel support rods circumferentially and uniformly distributed at the bottom thereof, and the support rods are fixed to the lower cavity; correspondingly, steel support rods which are circumferentially and uniformly distributed are also arranged on the upper die cavity; preferably, the support rods on the upper die cavity and the lower die cavity are in a one-to-one corresponding and symmetrical distribution form;

preferably, the outer diameter of the support rod is phi 12 mm-phi 16mm, and the support rods are circumferentially and uniformly distributed at intervals of 60 degrees.

8. A method for producing a connecting pipe member of a plastic composite pipe, which is performed by the connecting pipe member production apparatus of any one of claims 1 to 7, comprising the steps of:

(2) and (3) preserving the heat of the molten fluid in the storage cylinder, performing secondary plasticization, injecting the molten fluid into a forming die under the action of a motor of the storage cylinder, mounting a steel mesh framework in the forming die in advance, and wrapping the steel mesh framework in the forming die after the molten fluid is injected into the die to form the plastic composite pipe.

9. The apparatus for producing joined pipe members of plastic composite pipe as claimed in claim 8, wherein the steel mesh skeleton has supporting nails of equal length uniformly fixed on the outer surface thereof;

preferably, the supporting nails are distributed at intervals of 60-90 degrees in the circumferential direction, and the interval between the upper and lower adjacent supporting nails is 80-100 mm.

10. Use of a device for producing joined pieces of plastic composite pipe according to any one of claims 1 to 8 and/or of a product produced by the method according to claim 9 in the field of pipe work.