SU994283A1 - Extrusion head for making sinuous articles of thermoplastics - Google Patents

Description

'The invention relates to the field of polymer engineering, in particular to units for the production of rods and threads, shaped products, hoses, etc., obtained by the method ^? 'extrusion from various thermoplastics.

A known extrusion head for the manufacture of products combined from various thermoplastics, comprising a housing with several inlet channels * 0 and a mandrel forming an annular forming cavity with the housing, divided in the lower part by demarcation elements into two forming sections communicating with the input 15 channels and connecting in its upper part into a common molding ·. gap [1].

The disadvantages of the known extrusion head are the insufficient strength of the welded joint of polymer flows with various properties supplied by individual extruders, due to poor mixing of poorly compatible plastics in * 5 cavities of the delimiting elements, and the high hydraulic resistance of the forming head due to the delimiting elements and mixing chambers with small diameters output - 30; ny holes. In addition, on this head it is impossible to obtain rod. And profile combined products.

The closest in technical essence, and the achieved result to the invention is an extrusion head for the manufacture of crimped products from thermoplastics, comprising a housing with inlet pipes in communication with the extruders, a sleeve with a channel for the passage of material connected with a rotation drive, and a mouthpiece placed in the housing with forming channel (2]. _

The disadvantage of this extrusion head is the large hydraulic resistance due to the fact that в during the extrusion process, the flows of polymer melts must be divided into several parts and receive rotation from a distribution sleeve having four channels made peripherally, which limits the throughput. In addition, the distribution sleeve experiences a large radial pressure from two oppositely located extruders connected at a 90 ° angle to the die. From the hole in the distribution sleeve do not provide continuity of flows and uniform pressure at the inlet to the mouthpiece. The flow from the inlet fitting of the extruder changes its direction by 90 ° at the entrance to the openings of the distribution sleeve, which violates the uniform outflow of polymer melts and leads to an uneven velocity distribution profile at the mouth of the nozzle.

The purpose of the invention is to: improve the quality and mechanical strength and productivity of the head by reducing hydraulic resistance, improving the uniform distribution of melt flows.

This goal is achieved by the fact that in the extrusion head for the manufacture of crimped products from thermoplastics, containing a housing with inlet pipes in communication with the extruders, a sleeve with a channel for the passage of material connected with a rotation drive, and a mouthpiece with a forming channel, placed in the housing, the sleeve channel for the passage of material at the input section is in communication with the supply pipes and is made with distribution projections of a triangular shape. thirty

In addition, the extrusion head is equipped with a transition disk with a conical chamber located between the inlet pipes and the sleeve.

In FIG. 1 shows an extrusion head 35, a longitudinal section; in FIG. 2 is a view A in FIG. 1) on fig.Z section of the BB channel with vstoyami.

The head comprises a detachable housing 1 with inlet pipes 2 associated with extruders (not shown in the drawing). In the housing 1 there is a sleeve 3 with a channel 4 for the passage of material mounted on radial 5 and thrust bearings, which are separated by a sleeve 7. Bearings 3 + 5 nicknames 4, 5 are mounted in the housing 1 by a cover 8 with bolts 9 and separated by bushings 10 from the worm wheel 11 mounted on the sleeve 3. The worm 12 is placed in the bearing assemblies 50 and 13 and 14, which are connected by bolts 16 with bolts 16 to the brackets 17 welded to the housing 1 and closed by a casing 18 (see Fig. 2. )

In the bearing cap 8, 55 is fixed to the thread of the mouthpiece 19 with the forming channel 20.

The channel 4 for the passage of material with communicated with the nozzles 2 through the adapter disk 21 with a conical chamber & d 22 and the seal 23 ·. The inlet pipes 2 are mounted in the connecting nut 24 and are located 120 ° around the perimeter of the conical chamber 22. At the inlet section of the channel 4 ^ 5 of the sleeve 3, the distribution projections 25 are made of a triangular shape.

The extrusion head is heated by thermocouples (to hell, not shown).

The device operates as follows. ¹

The polymer melts supplied from various extruders come through nozzles 2, are forced through the chamber 22 of the disk 21, where the polymer flows are mixed. Further, the material enters the inlet section of the channel 4 of the sleeve 3, where the points of the distribution protrusions 25 the polymer flows are captured and twisted during rotation. Further polymers twisted threads extend over the entire length of the channel 4 and fed to the mold channel 20 of the mouthpiece 19 as _h GDIN crimped polymeric rod. The calibrated crimped extrudate leaves the forming channel 20 corresponding to its profile. In crimped polymer products, denser connecting seams are formed, and the combined extrudate has a higher mechanical tensile strength.

When the sleeve 3 is rotated at the beginning and at the end of the channel 4, a complex shear occurs, which reduces the effective viscosity and reduces the hydraulic resistance, which can significantly increase the space velocity of the extrudate exit.

In areas of complex shear, enhanced homogenization of polymers occurs, which positively affects the quality of crimped products.

By varying the speed of rotation of the sleeve 3 and other technological parameters, it is easy to achieve the optimum mode of processing of polymers with any physicochemical properties.

Using the invention will allow to obtain crimped combined products and to increase the productivity of the installation, to stabilize the continuity of the flow and thereby increase the mechanical strength of the products by 15-20%.

Claims (2)

- -:. . , one; The invention relates to the field of polymer engineering, in particular to units for the production of rods and yarns, profile hose pipes, etc., obtained by extrusion from various thermoplastics. A known extrusion head for manufacturing products combined from different thermal plastics, comprising a housing with non-core input channels and turf, treatment with a case of a ring-shaped cavity forming the divided in the lower part of the demarcation elements into two forming areas, together with input channels and soedyn yuschiesd in its upper part, in the general shape of ---. slit l A disadvantage of the known extrusion die is the insufficient strength of the welded connection of polymer flows with different CTBcUvM of their own, supplied by separate extruders, due to poor mixing and poor mixing of the plastics in the hollow of the demarcation elements and the large hydraulic structure of the pulley, because of the poor mixing of the plastic in the cavity of the limiting elements and the large amount of pressure from the plastic in the hollow section of the extruders, and because of the poor mixing of the plastic in the hollow section of the extrusion elements and the large hydraulic structure, there was no reason for the plastic of the extruders. small mixing chambers with diameters of access holes. In addition, on this, the head can not get bar and profile combined products. .. The closest in technical essence, and the achieved result to the invention. is an extrusion head for the manufacture of crimped thermoplastic products, comprising a housing with inlets connected to extruders, a sleeve in the housing with a passageway for the material associated with the rotational drive, and a mouthpiece with a forming channel, t2. The disadvantage of this extrusion head is the presence of a large hydraulic resistance due to the fact that during the extrusion process the melt flows of the polymers must be divided into several parts and receive rotation from the races, the splitting sleeve, which is peripherally formed, which limits the throughput. In addition, the distribution sleeve suffers a large radial pressure from two opposing extruders attached at an angle of 90 ° to the head. Holes in the distribution sleeve do not provide continuity of flows and uniform pressure at the inlet to the mouthpiece. The flow from the extruder inlet nipple changes its direction by 90 ° at the entrance to the orifice of the distribution sleeve, which disrupts the uniform outflow of polymer melts and leads to an uneven velocity distribution profile at the outlet of the die. The purpose of the invention is to improve the quality and mechanical strength and performance of the head by reducing the hydraulic resistance, improving the uniformity of the distribution of the melt streams. The goal is achieved by the fact that in the extrusion head for the manufacture of crimped thermoplastic products, comprising a housing with inlet pipes communicated with extruders, a sleeve in the housing with a channel for the passage of material associated with a rotary drive, and a mouthpiece with a channel 1 The bushing channel for passage of the material at the inlet section communicates with the inlet pipes and is made with distribution protrusions of a triangular shape. In addition, the extrusion head is provided with a transition disk with a conical chamber located between the inlet pipes and the sleeve. FIG. 1 shows an extrusion head, a longitudinal section; in fig. 2 is a view A of FIG. 1J of FIG. 3 is a section B-B of a channel with alignments. The head contains a split housing 1 with inlet connections 2 communicated with extruders (on hell, not shown). The housing 1 houses a sleeve 3 with a channel 4 for the passage of material, mounted on radial 5 and thrust bearings, which are separated by sleeve 7. Subtypes 4, 5 are fixed in housing 1 with 8 clamps 8 and separated by sleeves 10 from Worm wheel 11, mounted on the sleeve 3, Cher in 12 is placed in the bearing assemblies 13 and 14, which with the help of plates 15 are connected by bolts 16 to the IT brackets, which are welded to the housing 1, are closed by the housing 18 (see FIG. 2). ). In the bearing cap B, a mouthpiece 19 with a forming channel 20 ... is fixed on the thread. A duct 4 of material passing through communicates with nozzles 2 through a transition disc 21 with a conical chamber 22 and a seal 23- "Inlet nozzles 2 are mounted into the connecting nut 24 and are located 120 along the perimeter of the conical chamber 22. At the entrance of the canyla 4, the sleeves 3 are made of distribution projections 25 of a triangular shape. The extrusion head is heated with thermocouples (in hell, not shown). The device works as follows. Polymer melts supplied from various extruders flow through the nozzles 2, are forced through the chamber 22 of the disk 21, where the polymer flows are mixed. Then, the material enters the entrance section of the channel 4 of the sleeve 3, where the edges of the distribution protrusions 25 capture the flow of polymers and coil during rotation. Next, the twisted polymer flows pass along the entire length of channel 4 and enter the forming channel 20 of the mouthpiece 19 as a single crimped polymer rod. The calibrated crimped extrudate leaves the forming channel 20 corresponding to its profile. Twisted polymer products form tighter connecting seams, and the combined extrudate has a higher mechanical tensile strength. When the sleeve 3 rotates, a complex shear occurs at the beginning and at the end of channel 4, which reduces the effective viscosity and decreases the hydraulic resistance, which allows a substantial increase in the extrudate volumetric output rate. In zones of complex shear, enhanced homogenization of polymers occurs, which has a positive effect on the quality of convoluted products. By varying the speed of rotation of the sleeve 3 and other technological parameters, it is possible to easily achieve the optimal mode of processing of polymers with any physical and chemical properties. The use of the invention will allow to obtain convoluted combined products and to increase the plant capacity, stabilize the continuity of the flow and thereby increase the mechanical strength of the products by 15-20%. extruders, a sleeve in the housing with a channel for the passage of material, associated with a rotating drive, and a mouthpiece with a forming channel, characterized in that The goal is to improve the quality and mechanical strength of products and the performance of the head due to reducing the hydraulic resistance, improving the uniform distribution of the melt flows, the channel. The sleeves for the passage of material at the inlet section are in communication with the inlet pipes and made with the distribution holes of the triangular forgAA. 2. The extrusion head according to claim 1, wherein it is equipped with a transition disk with a conical chamber located between the inlet pipes and the sleeve. Sources of information taken into account in the examination 1. Authors certificate of the USSR 397358, cl. In 29 F 3/04, 1971. 2. Shenkel G. Screw presses for plastics. L., Goskhimizdat, 1961, p. 288, 289 (prototype).