JPH0481921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for producing ceramic thermal spray wire.

[Conventional technology and its problems]

Ceramic spray wire is made by mixing fine ceramic powder with a binder and sintering it into a flexible ceramic spray rod, and mixing fine ceramic powder with binder, plasticizer, lubricant, water, etc. There is also a plastic ceramic spray wire that is extruded and dried.

As shown in Japanese Patent Publication No. 48-22809, the conventional manufacturing method for ceramic sprayed wire is to put a mixture of the above-mentioned materials into a container equipped with a molding die at the bottom, and press it into a ram. Therefore, it is a press type in which the mixture is pressed and the ceramic sprayed wire having a desired outer diameter is formed from the die.

However, in this press-type production method, the ram is pushed down to the bottom of the container to extrude the mixture, then the ram is removed and the mixture is put in again.
Since it is a batch type extrusion method, there is a limit to improving productivity. Further, in the batch type, the length of the sprayed wire is limited, and it is inconvenient to wind the flexible sprayed wire on a bobbin.

Therefore, it is conceivable to adopt a screw type extrusion molding machine for continuous molding of the power cable insulation layer in place of the container and ram. However, the mixture for ceramic thermal spray wire forming is highly slippery and has low shear resistance, so it does not bite into the screw rotating inside the cylinder, so-called slippage occurs, and the mixture is not conveyed smoothly. Therefore, there is a problem that it is not possible to obtain a ceramic sprayed wire of stable quality. For this reason, the continuous extrusion molding method has not been employed until now in the production of ceramic thermal spray wires.

[Object of the Invention] In view of the above-mentioned problems, an object of the present invention is to provide an apparatus for producing a ceramic thermal spray wire of stable quality by a continuous extrusion method with good productivity.

[Means for achieving the purpose of the invention]

In order to achieve the above object, in the manufacturing apparatus of the present invention, a crosshead is provided at the tip of the cylinder into which the screw is inserted, and
At the rear end of the cylinder, two or more hoppers containing a mixture of fine ceramic powder are connected via gates, and each hopper is provided with means for pressurizing the mixture.

[Effect]

The manufacturing equipment configured in this way first fills each hopper with a mixture of ceramic fine powder, opens the gate of any hopper to pressurize the mixture in that hopper, and turns the screw to pressurize the mixture. The mixture to which the mixture has been added is fed into a cylinder and is steadily bitten into a screw one after another and conveyed, and at a crosshead, the mixture is extruded to produce a thermal spray wire.

Immediately before the mixture in the hopper whose gate is open runs out, the gates of other hoppers open and the mixture is pressurized and fed into the cylinder, and the cylinder is continuously pressurized. A mixture of states is supplied. After supplying the mixture, the gate of the hopper is closed and the mixture is newly filled into the hopper.

The above operations are repeated to continuously extrude the ceramic sprayed wire.

Incidentally, the term "mixture of fine ceramic powder" refers to a paste-like material obtained by mixing a binder, a plasticizer, etc. into a thermal spray material made of fine ceramic powder or granules, and kneading the mixture with water. Examples of the ceramic include one or a mixture of two or more of alumina, titania, zirconia, magnesia, silica, calcia, yttoria, tungsten carbide, chromium carbide, and the like. Examples of the binder include cellulose derivatives consisting of one or a mixture of two or more of sodium cellulose glycolate, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methacrylic resin, and low molecular weight polyvinyl alcohol, and the plasticizer includes , such as glycerin.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

As shown in Figure 1, a crosshead 3 is attached to the tip of the cylinder 2 into which the screw 1 is inserted over its entire length.
A hopper 4 is provided, and the rear end is divided at the center to form two hoppers.The first and second chambers 4a and 4b of this hopper are connected to the cylinder through gates 5a and 5b, respectively, which are opened and closed by the cylinder. Connected within 2.

At the top of each chamber 4a, 4b of the hopper, cylinders 6a, 6b are provided as pressurizing means.
The cylinders 6a, 6b can be moved backward via a slide plate 7, and the hopper 4 is filled with the above-described mixture a of fine ceramic powder.

The embodiment is configured as described above, and its operation will be explained next.

First, the mixture a is placed in each chamber 4a and 4b of the hopper 4.
After filling the cylinder 6, open one gate 5a and
When a is driven to pressurize the mixture a and the screw 1 is turned, the mixture a to which the pressurizing force is applied is
is fed into the cylinder 2, is steadily bitten by the screw 1, and is conveyed to the crosshead 3, where the mixture is extruded from the die into a rod shape to produce the sprayed wire b.

Just before the mixture a in the first chamber 4a runs out (just before the rod of the cylinder 6a reaches the lower end), its advancing (descending) speed decreases, and the other gate 5b opens to start driving the cylinder 6b, causing the rod to advance. When the speed reaches the required pressure, one of the gates 5a closes and the rod of the cylinder 6a retreats. The other cylinder 6b continues to be driven, and the mixture a is supplied into the cylinder 2 from the second chamber 4b, so that the sprayed wire b is continuously extruded.

On the other hand, the cylinder 6a from which the rod has retreated is moved back via the slide plate 7 to open the upper surface of the first chamber 4a, fills the chamber 4a with a new mixture a, and waits for the supply to be switched from the second chamber 4b.

The above operations are repeated to continuously extrude the ceramic sprayed wire b. Incidentally, FIG. 2 shows an operation time chart of the cylinders 6a and 6b.

In the embodiment, the number of chambers forming the hopper is two, but it goes without saying that the present invention can be applied even if there are more than two chambers.

Furthermore, although the thermal sprayed wire b in the examples does not have an outer covering, when manufacturing a thermal sprayed wire with an outer covering like the thermal sprayed wire described in the above-mentioned Japanese Patent Publication No. 48-22809, the thermal sprayed wire b in the examples is , a screw cylinder 2 with a hopper 4 configured according to the present invention for extruding the jacket may be attached to the crosshead 3.

〔Effect of the invention〕

The present invention is configured as described above, and the mixture is fed into the screw under pressure, and this feeding can be done alternately, so that ceramic spray wire of stable quality can be continuously produced. It can be manufactured easily and productivity is improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of a ceramic spray wire manufacturing apparatus according to the present invention, and FIG. 2 is a time chart for explaining the operation. 1... Screw, 2... Cylinder, 3... Crosshead, 4... Hopper, 4a... First chamber,
4b...Second room, 5a, 5b...Gate, 6a,
6b...Cylinder, a...Admixture, b...Ceramic sprayed wire.

Claims (1)

[Claims] 1. A crosshead is provided at the tip of a cylinder into which a screw is inserted over its entire length, and at the rear end of the cylinder, two or more hoppers containing a mixture of fine ceramic powder are connected via gates, and each hopper An apparatus for producing a ceramic thermal spray wire, characterized in that a means for pressurizing the mixture is provided in the apparatus.