JPS5810257Y2 - extrusion coating machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an extrusion coating machine for extruding and coating a conductor with an inner and outer semiconducting layer and an insulating layer.

Generally, in the production of electric wires with extrusion coatings of rubber or plastic for high voltage use, three layers, an inner semiconductive layer, an insulating layer, and an outer semiconductive layer, are extruded onto a conductor using three extruders.

That is, as shown in FIG. 3, an extruder 5' extrudes the inner semiconductive layer onto the conductor 1', an extruder 5' extrudes the insulating layer 4', and an extruder 7' extrudes the outer semiconductive layer 6'. Using three extruders, the inner and outer semiconductive layers z, 6' and the insulating layer 4' are coated by extrusion from a common common head 8', and the management and maintenance of the three extruders and the space for installing them are It required

However, since the inner and outer semiconductive layers 2' and 6' are made of the same material, these extruders 3' and 7' are used in common, and one extruder is used to supply the material to the common head 81 via a branch pipe. An extrusion coating machine has been developed in which three layers are extruded and coated using two extruders.

This makes management and maintenance easier and requires less installation space compared to extrusion coating using three extruders, but the inner and outer conductive layers are thinner and the dimensions (inner and outer diameters) are different. Since the extruders were also different, it was difficult to extrude both products homogeneously.

In view of this, the present invention allows the flow rate of the inner and outer semiconductive layers to be extruded by a common extruder to be adjusted separately.In other words, a pump is inserted in each branch pipe for extruding the inner and outer semiconductive layers. It is characterized by

Next, this will be explained in more detail based on the drawings.

FIG. 1 shows an example of an extrusion coating machine according to the present invention, in which materials for the inner semiconductive layer 2 and the outer semiconductive layer 4 are transferred through a branch pipe 5 using a common extruder 3. This is the same as the conventional method in that the material for the insulating layer 6 is supplied to the common head 8 by an extruder 7, and these materials are extruded and coated onto the conductor 1. ,
In the present invention, a pump 9 is inserted into each of the branch pipes 5, so that the flow rate of the material for the semiconducting layer flowing through the branch pipes 5 can be adjusted separately.

In particular, if a gear pump is used as the pump 9, which feeds the material by rotating a pair of gears 10 as shown in FIG. The flow rate of the material passing through can be freely adjusted, and even if the material passing through the branch pipe 5 causes pressure fluctuations due to the rotation of the screw of the extruder 3, it is not affected much and the discharge amount is approximately constant. Therefore, it is possible to obtain a homogeneous extrusion coating suitable for the dimensions of the inner and outer semiconducting layers.

As explained above, according to the present invention, it is possible to extrude and coat the three layers of the inner and outer semiconductive layers and the intermediate insulating layer using two extruders, and also to use a branch pipe for extruding the inner and outer semiconductive layers. Since a pump that can separately adjust the flow rate is inserted, homogeneous inner and outer semiconducting layers can be easily provided, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an extrusion coating machine according to the present invention;
FIG. 2 is an explanatory diagram of a pump inserted in a branch pipe of the present invention, and FIG. 3 is an explanatory diagram of a conventional three-layer extrusion coating machine. 1... Conductor, 2, 4... Inner and outer semiconductive layers, 3... Semiconductive layer extruder, 5...
... Branch pipe, 7 ... Extruder for extruding the insulating layer 6, 8 ... Common head 9 ... Pump.

Claims (1)

[Scope of utility model registration request] Two extruders are installed, one for extruding the inner and outer semiconductive layers of the conductor and the other for extruding the intermediate insulating layer. 1. An extrusion coating machine for extruding three layers in which a common head is provided with a passage for guiding extrusion material, and the extrusion coating machine is characterized in that a pump is inserted in each of the branch pipes.