CN202097938U - Plastic extruding machine with curved type machine-neck flow channel - Google Patents

Abstract

The utility model discloses a plastic extruding machine with a curved type machine-neck flow channel. The plastic extruding machine is provided with the machine-neck flow channel; the longitudinal section shape of the machine-neck flow channel is curved; the curve is that y is equal to ax2, wherein a is equal to (D-d)/2-R; R is the radius of an arc at the edge of a horn; D is the large caliber of the horn, i.e., the inner diameter of a spiral drum of a machine body; and d is the small caliber of the horn, i.e., the diameter of an inflowing machine head hole. By reasonably arranging the shape of the machine-neck flow channel, the machine-neck flow channel is matched with the flow characteristic of plastic melt under the melting state, so that the flow speed of the extruded polymer melt is increased, and the temperature is uniform; and no dead angle exists in the curved type flow channel and the defects such as agglomeration and the like can not occur.

Description

A kind of extruding machine with shaped form machine neck runner

Technical field

The utility model relates to the cable production field, specifically is a kind of extruding machine, particularly a kind of extruding machine with shaped form machine neck runner.

Background technology

Extruding machine mainly is made up of extrusion system, transmission system and heating and cooling system.Extrusion system wherein comprises screw rod, machine barrel, hopper, head and mould, and plastics plastify into uniform melt through extrusion system, and in this course under institute's build-up pressure, by the continuous extruder head of screw rod.

Head is made up of cover and carbon steel overcoat in the steel alloy; Mould is housed in the head, and the effect of head is to change the plastic melt that rotatablely moves into the parallel lines motion, in the importing die sleeve of uniform and stable; And give the briquetting pressure of plastics with necessity; Plastics plastify compacting in machine barrel, flow into head mould, core rod die sleeve proper fit along certain runner through the head neck through the porous filter plate; Form the ever-reduced annular space in cross section, make plastic melt around heart yearn, form closely knit tubulose clad continuously.For guaranteeing that plastic passages is reasonable in the head, eliminate the dead angle of accumulating plastics, often be mounted with dividing bushing, pressure oscillation when extruding for eliminating plastics also has grading ring is set.

Like Fig. 1, at present, the machine neck of extruder head all adopts linear pattern horn mouth structure, and it and extruding machine fuselage are easy to connect, processes also simply, and the plastic melt that is extruded gets into head by the trumpet type runner through the machine neck in the fuselage.Because in the straight line trumpet type runner, volume and pressure are linear, and be non-linear rheid in melting state current downflow characteristic, i.e. non-newtonian fluid by the plastic melt that squeezes.Therefore in practical operation, existing straight line trumpet type flow passage structure exists cavity volume big, and the cross-polymer melting rate of flow of fluid that is squeezed is slow, non-uniform temperature, and flow path wall is prone to produce the dead angle, can produce stiff piece in the melting body and become dead burnt defectives such as analyte.

The utility model content

The utility model technical problem to be solved provides a kind of plastic melt and extrudes evenly, can not produce the extruding machine of defectives such as stiff piece in the melting body.

The described extruding machine of the utility model with shaped form machine neck runner, this extruder has machine neck runner, it is characterized in that the longitudinal cross-section of this machine neck runner is shaped as shaped form, and this curve is:

y=ax ²?，

A=

wherein

RBe loudspeaker limit arc radius; DBe the loudspeaker heavy caliber, i.e. fuselage barrel internal diameter; dSmall-bore for loudspeaker, promptly flow to the head bore dia.

In the hydrodynamics, the speed that fluid flows in circular pipe, no matter be that newton-type or non-Newtonian fluid all can be supposed the genus steady flow condition that flows, shear stress is zero at tube hub, increases gradually to tube wall, and is maximum at the tube wall place.Thereby the VELOCITY DISTRIBUTION of fluid in conduit be maximum at tube hub, reduces gradually to tube wall, and be zero at the tube wall place.Concerning Newton type fluid, this VELOCITY DISTRIBUTION is parabolic type, and concerning non-Newtonian fluid, this parabola is point (high polymer PVC is the typical case particularly) slightly.Therefore, high polymer melting body flows into the bell-mouthed machine neck of linear pattern by the stable extruding of fuselage, and the relative tube hub of its speed on straight walls reduces, and this just very easily causes viscous flow, and promptly high polymer adheres to tube wall one-tenth " dead burnt ".And pipeline that should the zone is set to the curved wall of functionality, has just in time eliminated " hotbed " of " dead burnt ", reduces regional volume simultaneously, and this makes the waste material of shutting down the cleaning machine neck reduce again, and is comparatively favourable to the technology cost of practicing thrift in producing.The utility model promptly is through the shape of machine neck runner rationally being set, itself and plastic melt are complementary in melting state current downflow characteristic, make the high polymer melting body that is extruded flow in the pressure of each aspect even, flow velocity speeds, temperature is even; And there is not the dead angle in the shaped form runner, extrudes layer and defectives such as stiff piece can not occur.

Description of drawings

Fig. 1 is the prior art constructions sketch map,

Fig. 2 is the structural representation of the utility model.

The specific embodiment

Like Fig. 2, the extruding machine of the utility model has shaped form machine neck runner 1, and the longitudinal cross-section of this machine neck runner 1 is shaped as shaped form, and this curve is:

(1) machine neck runner adopts y=ax ²Function.

(2) constant a is confirmed by the barrel diameter and the head inflow entrance aperture of fuselage, is specially a=

(annotate: RBe loudspeaker limit arc radius; DBe the loudspeaker heavy caliber, i.e. fuselage barrel internal diameter; dSmall-bore for loudspeaker, promptly flow to the head bore dia).

(3) smooth (radius of circle of trumpet type edge arc R), get circumference

, no dead angle.

(4) the whole trumpet type origin of curve is breasted the tape the location accurately, and Machining of Curved Surface does not have the dead point.

The utility model provides a kind of thinking and implementation method with extruding machine of shaped form machine neck runner; Concrete application approach is a lot, and the above only is the preferred implementation of the utility model, should be understood that; For those skilled in the art; Under the prerequisite that does not break away from the utility model principle, can also make some improvement, these improve the protection domain that also should be regarded as the utility model.

Claims (2)

1. extruding machine with shaped form machine neck runner, this extruder has machine neck runner (1), it is characterized in that the longitudinal cross-section of this machine neck runner is shaped as shaped form.

2. the extruding machine with shaped form machine neck runner according to claim 1 is characterized in that this machine neck passage curve is shaped as:

y=ax ²?，

A=

wherein

RBe loudspeaker limit arc radius; DBe the loudspeaker heavy caliber, i.e. fuselage barrel internal diameter; dSmall-bore for loudspeaker, promptly flow to the head bore dia.

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