SU874384A1 - Extrusion head for producing polymeric material articles - Google Patents

Description

(54) EXTRUSION HEAD FOR MANUFACTURING PRODUCTS FROM POLYMER MATERIALS

I

The invention relates to the processing of polymeric materials, in particular to forming equipment for the manufacture of tubular products by extrusion, and can be used in the chemical industry.,

A known extrusion die for the manufacture of products from polymeric materials, comprising a housing with under, melting channels and forming elements, which form successively arranged collector, balancing, stabilizing and output channels with the housing.

The collector, equalization channels are intended to evenly distribute the processed material over the outflow (extrusion) front, and the forming channels only to control the overall thickness of the product 1.

A drawback of the extrusion head is the absence of elements that provide the necessary distribution of the flow of rasplav and the absence of elements regulating the dimensions of the channels for the melt.

The closest in technical essence and the achieved result to the invention is an extrusion head for manufacturing products from polymeric materials, comprising a housing made with inlet channels and throttling and forming elements mounted therein forming with the housing and between themselves successively located collector, balancing, throttle , stabilizing and output channels communicated with supply channels.

The presence of the throttling element, formed in the form of a ring, provides adjustment of the throttle channel 2.

The disadvantage of this head is a sharp increase in the pressure area in the region of the throttle channel (it is somewhat removed

J5 from the collector), which entailed the reinforcement of the connecting threads (in order to avoid not only damage, but also open the joints between the forming elements and the body). For this reason, as well as others, such as layout considerations,

20 head large, massive. Accordingly, the starting power and the start-up time of the head increased, its operation became more complicated with the release of large-diameter hoses. In this head, the load on the throttling element is increased. In addition, in the specified head, there is no qualitative distribution of the melt; in the channels, "dead zones" are formed, which significantly reduces the quality of the products. The purpose of the invention is to improve the quality of products. This goal is achieved by the fact that the extrusion head for the manufacture of products from polymeric materials, comprising a housing made with supply channels for the melt and throttling and forming elements mounted therein, forming successively collector, equalization, throttle, stabilizing and the output channels communicated with the supply channels, the throttling element is made with annular grooves limiting the collector channel and the fairings formed intersecting concave surfaces and located at the intersections of the collector channel with supply and equalizing channels. FIG. Figure 1 shows an extrusion head, a general view; in fig. 2 shows section A-A in FIG. one; in fig. 3 shows the node I in FIG. 2 (increased); in fig. 4 shows a section BB in FIG. 3; in fig. 5 shows a section B-B in FIG. 3; in fig. b - section GGD in FIG. 3. The head contains body 1, mandrel 2, mouthpieces 3, calibrating rings — inner 4 and outer 5, adjusting screws 6, throttling element 7, threaded rods 8, threaded bushings 9, pins 10, lid 11, air supply tube 12 and seals 13 and 14 (Fig. 4 and 5). In the case 1, supply channels D are made, and the forming elements (mandrel 2, mouthpieces 3, calibrating rings 4 and 5) and throttling element 7 form with the case 1 and in series with each other communicating with the supply channels D sequentially located collector E, equalizing G , throttle AND, stabilizing K and output L channels. The height of the channel L is changed by moving the ring 5 by adjusting screws 6. The height of the throttle channel I is changed by means of a threaded rod 8, a threaded sleeve 9 and a finger 10 ,. The seals 13 and 14 in this head are made in the form of deformable rings of a wedge-shaped cross section. Depending on the operating temperature of the head made of fluoroplastic, aluminum, copper, lead and its alloys, they can be made. The melt is supplied in three channels D equally spaced around the circumference (Fig. 2). From each of these channels, two collector channels E, made in the throttling element 7 in the form of grooves, symmetrically diverging from the plane passing through the longitudinal axis M of the head (Fig. 1) and the axis N of the supply channel D (Fig. 2), start. The beginnings and ends of the collector channels are made with smooth transitions (Fig. 3 and 6). The throttling element 7№1 is filled with the input fairing 15 and the output fairing 16 formed by intersecting concave surfaces and providing self-cleaning of the collecting channels and their transition zones at the input of the supply channel D and the output of the collecting channel E to the equalization channel F and the throttle channel I. The fairings can be made in the form of individual parts installed in the respective landing slots made in the throttling element 7. Preliminary alignment of the melt flow entering From the collector channel E to the throttle channel I, it is produced by changing the size and shape of the equalization channel G by changing the shape and dimensions of the throttling element only in the zone of its contiguity with this channel (Fig. 4 and 5, for example, changing the aspect ratio: 6,; / L,; U / Sy,) This ensures the highest possible leveling of speeds at constant (uniform) values of the height of the throttle and output channels I, L (Fig. four). This achieves a further maximum effect of controlling the distribution of velocities during throttling by minimal deformation (minimum movement) of the throttling element 7. When manufacturing the fairings 15 and 16 at the same time as a whole with the throttling element 7, the necessary mechanisms for reliable and efficient operation are, for example , including threaded rods 8 and threaded bushings 9. The directions of flow and movement of the melt in the drawings are shown by arrows. The extrusion head works as follows. The material melt is injected through channels D into the collector channels E and then evenly distributed through the equalization channel J and the throttle AND throughout the perimeter of the channels K and L. At a constant value of the height of the output channel L and a uniform distribution of temperature along the perimeter of this channel, melt by locally moving the throttling element (changing the height of the channel I) using the screw adjusting mechanisms attached to it (by turning the threaded sleeves 9). After that, using screws 6, a more subtle local adjustment of the height of the output channel L is performed. The output hose billet is inflated with air supplied through the tube 12.

As a result of the collector channel in the throttling element and the use of the latter to form an equalizing channel, the dimensions and mass of the head are significantly reduced, compared to the known ones, the heating and start process is simplified, the load on the threaded joints holding the core in the housing is reduced (since the corresponding the protrusions necessary to form a special collector and an equalizing slit).

On average, in the manufacture of, for example, tubular films, the dimensions of the head are reduced by 20-50 ° / s depending on the type of material being processed and the diameter of the sleeve (mainly due to the height of the head). Reducing the dimensions (material), respectively, reduces the consumption of electricity during operation.

The presence of fairings provides self-cleaning channels, high-quality distribution of the melt, eliminating the stagnation of the material in the transition zones and in the collector channels. Simplified setup and head cleaning. The insignificant complication of the throttling element due to making grooves in it is covered by the listed advantages.

Claims (2)

1. Kaplun Ya.B. Forming equipment extruders. M., “Mashiyostroenie, 1969, p. 24 and 25. 2. The UK patent number 1271559, cl. In 29 F 3/04, published. 1972 (prototype). FIG. 3 6-6 Phma.