JPH0420502Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is a method for continuously heating and feeding metal powder or ceramic powder in the preheating process when compression molding metal powder or ceramic powder. This relates to a heating supply machine.

(Prior art) Conventionally, in the preheating process when compression molding powders such as iron powder, aluminum powder, alloy powder, or ceramic powders such as alumina, zirconia, and silicon carbide whiskers, these objects are continuously heated. The following devices are known as devices that supply heat while heating. (A) A device in which a transfer screw is placed inside a metal cylindrical cylinder and a heater is provided outside the cylindrical cylinder.

In this apparatus, the material to be processed in the hopper is fed into a cylindrical cylinder, and while being transported through the cylindrical cylinder by a screw inside the hopper, it is heated by a heater from the outside of the cylinder.
This equipment uses nichrome wire, etc. as an external heater, so there is a risk of heater breakage, and heat loss occurs as heat is transferred to the internal workpiece through the cylindrical cylinder. Furthermore, uneven heating was unavoidable.

(B) A device that uses electromagnetic waves as a heating source to directly heat and supply the processed material.

In this equipment, the objects to be processed include metal powder, silicon carbide,
If the material has good electrical conductivity, such as graphite, when electromagnetic waves are directly irradiated, part of the electromagnetic waves will flow on the particle surface as surface current. As a result, minute corona discharges occur because the potentials of individual particles differ, and combustible substances adhere to the powder surface, creating a risk of explosion if air gets mixed in.

(C) As described in JP-A-59-150014, a device that uses electromagnetic waves as a heating source, has a cylindrical cylinder made of an electromagnetic wave absorber, and causes the cylindrical cylinder to absorb the electromagnetic waves and generate heat.

In this device, since the cylindrical cylinder is made of ceramic, it is difficult to process the cylinder with high precision as in the case of metal, and therefore it is necessary to form a large gap between the cylinder and the screw rotating inside the cylinder. Due to the existence of this large gap, the material to be processed that is not transferred by the screw is deposited inside the cylinder, resulting in a decrease in heating efficiency due to the deposited powder and a change in physical properties due to long-term heating of the deposited powder. will occur. Furthermore, since the cylinder is fixed, it is likely to be locally absorbed by electromagnetic waves, resulting in uneven heating on the surface of the cylindrical cylinder.

(Purpose of the invention) This invention was made in order to eliminate these conventional drawbacks.It uses electromagnetic waves as a heating source and is capable of continuous heating of the processed material without uneven heating or changes in physical properties. It provides a feeding machine.

(Structure of the device) This device is a device that heats a workpiece while transferring it through a cylinder with a screw, and the cylinder is configured with a heating section in a part of its length, and the cylinder of this heating section is is composed of heat-resistant dielectrics such as graphite and silicon carbide, and the heating section is covered with a casing.A microwave oscillator is connected to this casing via a waveguide, and the cylinder of the heating section is rotated around its own axis. It is configured to be rotatable.

In the above configuration, the cylinder is heated by microwaves, heat is transferred to the object to be processed through the cylinder, and the object to be processed is prevented from adhering to the inner wall of the cylinder by rotating the cylinder itself.

(Example) In FIG. 1, a hopper 2 is attached to a metal front cylinder 1 of a heating supply machine, and a heating part cylinder 4 and a metal rear cylinder 11 are arranged coaxially with this cylinder 1. The cylinder is made up of: A screw 3 rotated by a motor (not shown) is disposed in the cylinder, and the rotation of the screw 3 transports the workpiece 10 supplied from the hopper 2 into the cylinder. The heating section cylinder 4
is made of a heat-resistant derivative such as graphite or silicon carbide, and is heated by irradiation with microwaves, which will be described later, so that the heat is transferred to the object to be processed inside.

Rear end of front cylinder 1 and rear cylinder 1
Flanges 31 and 12 are formed at the front end of 1, respectively, and a heating section is formed between the flanges 31 and 12.
2 and covered by a casing 6.
A waveguide 61 is attached to this casing 6, and this waveguide 61 is connected to a microwave oscillator (not shown). A heat insulating layer 7 whose both ends are held by the flanges 31 and 12 is provided around the outer periphery of the cylinder 4 of the heating section.

As shown in FIG. 2, a recess is formed in the inner peripheral surface of the flange 31, and a sleeve 5 having an L-shaped cross section is rotatably fitted into the recess, and the end of the cylinder 4 is rotated by the sleeve 5. Possibly supported. A slight gap is formed between the inner peripheral surface of the flange 31 and the outer peripheral surface of the cylinder 4. Also, the flange 31 has a cylinder 4.
A protrusion 32 is formed that protrudes toward the center of the
A yoke 33 is formed on this protrusion 32, and this yoke structure allows the cylinder 4 and the flange 31 to
This eliminates microwaves passing between the cylinder 4 and the cylinder 4, thereby preventing microwaves from entering the cylinder 4. The other end of the cylinder 4 is also constructed in the same manner as described above.

The sleeve 5 is made of alumina or non-ferrous metal oxide, and prevents the cylinder 4 from coming into direct contact with the flanges 31 and 12 made of metal material. The cylinder 4 is heated to a temperature corresponding to the material of the workpiece, but if the temperature is high, the cylinder 4 and the metal flanges 31, 12 are heated.
If they come into contact with each other, melting loss will occur due to the eutectic reaction of the iron-based alloy, so it is necessary to prevent the two from coming into direct contact.

The heating temperature of the object to be treated is 500 to 560°C for aluminum powder, 800 to 900°C for iron powder and alloy powder, and 1000 to 1200°C for ceramic (alumina, zirconia).

3 and 4 show another embodiment of this invention, in which a pair of outwardly protruding protrusions 81 are attached to the end of the cylinder 4 with a phase difference of 180 degrees, and the casing 6 is The above protrusion 81 is on the side wall.
A stopper 8 that locks on is attached so as to be movable forward and backward. The stopper 8 may be moved forward or backward by driving means using magnetic force or the like. The basic structure of the support portion of the cylinder 4 is the same as that shown in FIG. 1 above. In this configuration, since the protrusion 81 rotates together with the cylinder 4, the amount of rotation can be adjusted by moving the stopper 8 forward and backward to rotate or stop the cylinder 4 from rotating.

FIG. 5 shows yet another embodiment of this invention,
A gear 9 is attached to the outer periphery of the end of the cylinder 4, and a motor 9 is attached to the side wall of the casing 6.
A gear 92 rotated by the gear 9 meshes with the gear 9 and rotates the cylinder 4 via the gear 92.

Next, the operation of this device will be explained. Hopper 2
The workpiece 10 inside is supplied to the front cylinder 1 and transferred by the screw 3, while microwaves are irradiated from a microwave oscillator (not shown) through the waveguide 61, and the microwaves are transmitted through the heat insulating layer 7. The cylinder 4 is irradiated, thereby heating the cylinder 4 as a whole. Further, due to the rotation of the screw 3, a rotational force is transmitted to the cylinder 4 via the object to be processed inside (the cylinder 4 co-rotates due to the frictional force of the object to be processed), and the cylinder 4 also rotates slightly.
At this time, the cylinder 4 rotates with respect to the sleeve 5, and the sleeve 5 also rotates with respect to the flanges 31, 12, so that the cylinder 4 is rotated by a slight rotational force transmitted through the workpiece.

The object to be processed in the cylinder 4 is transferred while being heated by heat from the inner surface of the cylinder 4, and the object to be processed between the screw 3 and the inner surface of the cylinder 4 is transferred to the cylinder 4 because the transfer force of the screw 3 does not act on the object to be processed. However, because the cylinder 4 itself is rotating, the material to be processed gradually moves upward, falls, and is sent to the center (axis) side of the cylinder 4. Therefore, the object to be processed is prevented from adhering to the inner circumferential surface of the cylinder 4, and the object to be processed is uniformly heated and transferred. Furthermore, since heating by microwaves is applied to the rotating cylinder 4, uniform heating is achieved.

In addition, in the structure shown in FIG. 3, the rotation of the cylinder 4 can be adjusted by moving the stopper 8 back and forth, and in the structure shown in FIG. By adjusting the amount of rotation of the cylinder 4, it is possible to efficiently heat the object to be processed.

(Effects of the invention) As explained above, in this invention, the heating part cylinder is made of a non-metallic material such as graphite or silicon carbide, and is rotatable around its own axis.
This device uses microwaves to heat the object to be processed inside through the heating section cylinder, so the object to be processed does not adhere to the heating section cylinder, the object to be processed is heated uniformly, and it has excellent thermal efficiency. It is.

[Brief explanation of the drawing]

Fig. 1 is a central vertical sectional view showing an embodiment of this invention, Fig. 2 is an enlarged sectional view of the end of the heating section, and Fig. 3 is an enlarged sectional view of the end of the heating section.
The figure is a central vertical sectional view showing another embodiment of this invention.
4 is a sectional view taken along the line -- in FIG. 3, and FIG. 5 is a view corresponding to FIG. 3 showing yet another embodiment. 1...Front cylinder, 2...Hopper, 3...
Screw, 4... Heating part cylinder, 5... Sleeve, 6... Casing, 7... Heat insulation layer, 10...
...Object to be processed.

Claims (1)

[Scope of utility model registration request] It is a device that heats the object to be processed while being transferred by a screw through the cylinder, and the cylinder has a heating section in a part of its length, and the cylinder of this heating section is made of heat-resistant derivatives such as graphite and silicon carbide. The heating section is covered with a casing, a microwave oscillator is connected to the casing via a waveguide, and the cylinder of the heating section is configured to be rotatable around its own axis. A continuous heating supply machine for processing objects.