DE2301906A1 - Plastics kneading machine with degassing vent - has chamber adjacent to vent scraped by revolving blades to prevent vent becoming clogged - Google Patents

Abstract

A mixing of kneading machine, esp. a continuous kneading machine for plastics comprises a cylindrical housing and one or more kneading rotors revolving in the housing; a degassing vent is provided in the housing wall intermediate between the inlet and outlet; a chamber or path associated with this vent enables the material to be swept towards the cylinder wall. Each shaft is fitted with a projecting element which fits radially between the space and the degassing vent and scrapes the material away from this region as the shaft revolves, thus preventing material from clogging the degassing vent.

Description

Mixing or kneading machine The invention relates to a mixing or kneading machine and in particular on flow mixers (continuous kneaders), the are suitable for kneading plasticizable materials in an intensive Shearing and # kneading process can be processed. The plastic is made in such kneaders for example supplied in the form of powder and heated to a temperature therein, in which the powder forms a plastic mass by one end of the kneader is moved to the other end and a kneading, mixing and mixing process during is subject to its movement towards the exit from which it is squeezed.

In such kneaders, a measure must be provided for ventilation for volatile material fractions that are released when the material is processed, and Depending on the process, suction can be performed at the vent hole for removal such gases can be used. One of the problems of such general kneaders for kneading plastic, powder, solid or liquid materials is that Tendency of the pressurized material to come out of the valve opening during continuous Propelling the material through to step out of the kneader. This Loss of material and the resulting clogging of the ventilation opening undesirable for many reasons, and in a vacuum vent system the Contamination of the vacuum system pose additional problems.

It is therefore an object of the invention to provide a kneader in which Means are provided in an inner vent chamber leading to the vent opening cause the material to move continuously away from the vent and towards the discharge end of the kneader so that the leading to the vent opening Chamber possesses a kind of self-cleaning and the material is prevented from becoming move in and plug the vent.

It is a further object of the invention to design elnsier-like kneaders in such a way that that the accumulation of remaining material in any part of the kneader in the is essentially avoided, so that this old material is not with newly supplied Material can be mixed and contaminate it.

It is a further object of the invention to provide a kneader that is simple in structure and is economically manufactured and assembled can be.

This task is accomplished by a kneader with a cylinder liner that forms a material processing chamber and one in the axial direction to one another Having spaced inlet and outlet, which are connected to at least one in the cylinder liner essentially axially extending shaft, means for rotating the shaft, a radially extending, material advancing member the shaft communicating with a vent for the removal of gases with of the cylinder liner between the inlet and the outlet, one Exit path between the inlet and the outlet for directing the material to the Cylinder liner in a direction downstream from the vent opening from an upstream from the vent opening position, released according to the invention characterized in that a protruding element on the shaft substantially is provided radially between the Ausittsbeiweg and the vent opening, the is designed so that it the material when the shaft is rotated in one direction moved away from the vent.

In the kneader to be described this flows from a first section coming material into a second section through a neck section and this is surrounded by a gas collection chamber with a radially extending Hitlüftungs hole communicates. Helical prongs extend axially rearward into the gas collection chamber and are driven in a direction to move the Material out of the front of the chamber so that the material does not accumulate in it and interferes with the ventilation function. The kneader is preferably a twin-shaft kneader and has extruder screws in its second stage. The vent section is formed in a throttle or perforated plate sandwiched between sleeve sections for the first and second stage is layered.

Further features and expediencies of the invention emerge from the description of exemplary embodiments with reference to the figures. From the figures show: Fig. 1 is a partially sectioned side view of a flow mixer (continuous kneader) according to the invention; Fig. 2 is an enlarged cross section along line 2-2 in Figure 1; 3 shows an enlarged illustration the vent plate; and FIG. 4 is an enlarged partial view in perspective Representation of the rear end of the extruder barrel section, which after rear protruding helical vent chamber material direction reversal prongs demonstrate.

In the figures, a kneader housing 10 is shown with a first one Stage forming cylinder liner section 11 and a second stage forming Cylinder liner section 12 through an opening plate pushed in between 13 are separated. The kneader housing 10 can in a suitable manner from a frame F are worn, which has a base plate 10 a and feet 10 b.

The first cylinder liner section 11, which has a lateral insertion opening 14 is described in U.S. Patents 3,198,491, 3,423,074 and 3,463,459 which is referred to here so that only a brief description is given. He is provided with a sleeve 15 to form an annular space 16, the surrounds the cylinder liner section and through which, for example, a heating fluid can circulate continuously to heat the supplied through the opening 14 Material to the temperature suitable for mixing or kneading. The cylinder liner 10 is designed to create a mixing and kneading chamber 17 which has the shape of a Has eight in cross section and in which a pair of waves parallel in the axial direction 18 and 19 are mounted for rotation in the usual manner. A mechanism how it is described, for example, in US Pat. No. 3,198,491 or US Pat. No. 3,387,826, can drive the shafts 18 and 19 in the same direction of rotation and with the same Speed can be used.

At the ends 18 and 19 are at the current start end of the kneader Auger scraping sections 20 and 21 are provided to remove the material from the inlet opening 14 and add it to a series of mixing blades 22 and 23 on shafts 18 and 19 lead. The spatulas 22 and 23 are on their respective shafts in associated Pairs classified in the manner set out in the cited patents. she can be lenticular and offset one from the other by 900. The spatulas can be described as belonging together or as matching, than they are continuously against each other and also on the inner wall of the sleeve section 10 strip along.

The downstream end of the kneading chamber 17 is open, and the sleeve portion is provided with a flange 10a so that the orifice plate 13 can be suitably attached to it. 3 specifically shows the orifice plate 13, which has a rear wall or upstream wall portion 24 which carries a neck portion with a pair of forwardly protruding rings 25 which extend forward from the kneading chamber 17 and dispense the material therethrough.

It can here not shown opening size adjustment rings, as they in U.S. Patent 3,387,826 may be provided on shafts 18 and 19 to control the amount to be dispensed. The neck portions 25 are of an eight-shaped Gas-collecting chamber 26 which cut into the front surface of the plate 13 is surrounded and which leads to a radially outwardly extending vent opening 27 leads through the upper part of the plate 13. As already stated, the vent opening 27 are connected to a suction pipe, which from the kneader to a suitable Vent gas processing equipment can lead; the simplicity is however such a tube is not shown here.

The aforementioned bushing section 12 is designed to create an enlarged figure eight chamber portion 28 of the same size as the chamber 26 in plate 13, the chamber part 28 becoming smaller, as shown at 29, and merges into an eight-shaped chamber part 30 of a size that matches with the main body of the extruder screw sections 31 and 32 resting on the shafts 18 and 19 are attached to the output end of the kneader. The augers 31 and 32 that also strip against each other and of elongated round (lenticular) cross-section are shaped so that they are continuous on each other and on the chamber walls 30 strip along. They have helical screw parts 31 'and 32' that are gradual are radially enlarged at their upstream ends at 31 a and 32 a, so that they extend into the chamber sections 28 and 29.

Axially rearward or upstream from each section Protruding 31 and 32 are cooperating mutually rubbing pairs of helical ones Serrations 33 and 34 on the extruder screw section 31 and 35 and 36 on the screw section 32 provided. For clarity of the drawing, the different surfaces are not shown in engagement, but it is to be understood that the helical prongs 33 to 36 continuously on the radially inner and outer peripheral surfaces the chamber 26 stiff along as well as on the radial wall 24 and the radial front walls 25a of the two neck sections 25. The screw sections rub in the same way 31a and 32a along the chamber walls 28 and 29.

At the downstream end of the kneader is an ejector 37 provided with an axial discharge opening 38 from which the processed material can be squeezed out. Sections 18, 19, 22, 23, 31 and 32 can at the shafts 18 and 19 are keyed or formed in one piece with the same. The sleeve portion 12 is also preferably provided with flanges 12a and 12b to facilitate the attachment of the plate 13 and the ejector 37. Im the operation of the kneader is also described. The one to be mixed or kneaded Material is continuously fed through the inlet port 14 and emerges afterwards the correct mixture through the exit port 38 from. The main part of what needs to be done Mixing and kneading is carried out in the sleeve section 11 in the first stage and at the exit or downstream end of the sleeve 11, the material through the neck sections 25 having a reduced flow cross section pressed to a bubble chamber portion 28 which is the same size and shape as the chamber 17. That exiting on the neck section 25 and into the chamber sections Material entering 28 and 29 will begin to move into the vent 27 prevented by the prongs 33 to 36, which are rotated in one direction towards the Reverse any backward flowing material so that it is brought forward again becomes the homogenization part (metering portion) 30 in the can chamber. From the material Gaseous constituents that have been released can freely pass through the vent opening 27 step out. Prongs 33 and 34, similar to the abbreviated, spatula-shaped ones shown in FIG Have cross-section, graze continuously along the prongs 35 and 36, the have the same cross-section and in relation to the prongs 33 and 34 by 900 are offset against this.

Claims (5)

Patent claims 1 Mixing or kneading machine with a cylinder liner that has a material processing chamber forms and in the axial direction to each other a spaced inlet and Has outlet, with at least one located in the cylinder liner substantially axially extending shaft, means for rotating the shaft, a radially extending, Material advancing member on the shaft, a vent for removal of gases in communication with the cylinder liner between the inlet and the Outlet, an exit bypass between the inlet and the outlet for directing the Material to the cylinder liner in a direction downstream from the vent from a post ion located upstream of the vent opening, characterized in that that a protruding element (33, 34; 35, 36) on the shaft (18, 19) substantially provided radially between the exit path (25) and the vent opening (27) is, which is designed so that it is the material when rotating the shaft in a Moved direction away from the vent (27). 2. Mixing or kneading machine according to claim 1, characterized in that that the cylinder liner has a first section (10) and a second section (12) which are separated by the exit bypass, which is one in general has neck part (25) arranged radially opposite the vent opening (27), that one of the first and second cylinder liner sections (10, 12) is opposite one another the neck portion (25) enlarged cross-sectional area owns and that the neck portion (25) has a chamber (26) around it leading to the vent opening (27) causes the protruding means (33, 34; 35, 36) to be in general extend axially into the chamber (26) and are designed to be helical Returning the material in the chamber (26) in an axial direction from the Vent opening (27) away. 3. Mixing or kneading machine according to claim 2, characterized in that that at least one pair of shafts (18, 19) is provided in the cylinder liner and that the neck portion (25) has a pair of spaced apart neck portions (25), which are surrounded by the chamber (26), and that the protruding Means having co-operating prongs (33, 34, 35, 36) that graze one another, which are mounted on the shafts (18, 19), and that the shafts (18, 19) in the same Direction of rotation and driven at the same speed. 4. Mixing or kneading machine according to claim 3, characterized in that that each shaft carries a pair of prongs (33, 34; 35, 36) which are shaped so that they strip along the chamber (26), and that the prongs (33, 34; 35, 36) on the Shafts (18, 19) are angularly offset from one another relative to one another so that they don't bother each other. 5. Mixing or kneading machine according to claim 3, characterized in that that mixing screw sections (22, 23; 31, 32) are provided on the shafts (18, 19) which are separated by the neck portions (25) by which they are connected to one another stay in contact.