JPH0634376B2 - Infrared heating method - Google Patents

Description

The present invention relates to a method for uniformly heat-treating a molded article having a complicated shape such as a curved surface, unevenness or holes.

Conventionally, an infrared heating device with a reflective surface, in which an infrared radiator is arranged at the focal point of a parabolic or elliptical infrared reflective surface, prevents the scattering of infrared rays, and its radiant energy can be advantageously used. It is used for heat treatment of various molded products such as plastic, rubber, glass, and porcelain because it enables efficient heating at high speed and high temperature.

However, since such an infrared heating device with a reflecting surface uses the radiant energy of infrared rays, heating is greatly hindered in the portion of the object to be heated, that is, in the shaded portion, where the radiation does not go straight, and the radiation is directly struck. The heating temperature becomes lower than that of the portion, and so-called heating unevenness occurs.

For example, as shown in FIG. 4, using an infrared heating device with a reflective surface having four parabolic reflective surfaces and an infrared radiator,
When heating a molded product having a recessed portion as shown in the figure, the shaded portion of the inner surface of the body to be heated is a shaded portion where the radiation does not directly hit, so the heating temperature is lower than other portions, and the heating This causes unevenness and makes it impossible to perform sufficient heat treatment.
This means that, for example, in the case of heat treatment for the purpose of heat curing, uneven curing occurs, which adversely affects the final product.

Therefore, when the molded article is heat-treated by the infrared heating device with a reflecting surface, the present inventors heat the shadowed portion in the same manner as the other portions and cause uneven heating. As a result of studies to develop a method of heating uniformly without squeezing, the present invention has been achieved.

That is, the present invention, in the method of modifying the molded article by the infrared heating device with a reflective surface, by the hot fluid jet nozzle, which may be fixed, provided in the heating portion of the device,
An infrared heating method for a molded article, characterized by uniformly heating by blowing a high-temperature fluid heated to a predetermined temperature onto a portion of the object to be heated which is shaded by radiation from the infrared radiator. It is provided. As a heating device for carrying out the present invention, a gas blower or a pump,
A pipe having a fluid heating unit and provided with at least one jet nozzle at the tip thereof is connected, and the nozzle is provided in a heating portion of a heated object of an infrared heating device with a reflecting surface. An infrared heating device with a reflective surface that enables uniform heating can be used.

Hereinafter, the present invention will be described with reference to the drawings.

1 and 2 are schematic views showing a typical example of the method of the present invention. FIG. 1 is a front cross-sectional schematic view showing the positional relationship of a high-temperature fluid ejection nozzle with respect to an object to be heated (molded product).
Are schematic side sectional views showing the entire apparatus corresponding to FIG.

In the figure, a gas (for example, air) sent by a blower 5 is heated by a heater 6, and is blown as a high-temperature heating gas by a nozzle 4 onto a portion which is shaded by a radiation ray from an infrared radiator, as a high-temperature heating gas. To heat.

Here, the nozzle 4 is made of a material such as iron, copper, stainless steel, and aluminum that can sufficiently withstand the heating temperature, and is provided arbitrarily at the inlet, the outlet, or the inside of the infrared heating device with a reflecting surface, and its position. The shape of the heating device, the shape of the heating target, the shape of the object to be heated and other individual usage conditions are appropriately determined, but generally the length of the nozzle can be adjusted,
Further, it is provided so that it can be expanded, contracted, rotated, moved, etc. so that it can be freely bent and extended.

Of course, when the object to be heated is fixed, the nozzle may also be fixed.

As a matter of course, the tip of the nozzle is provided so that the ejection direction of the nozzle is directed to the portion of the object to be heated whose shadow is in the shadow of the radiation.

Also, the number of nozzles does not have to be one, and two nozzles can be used as needed.
Oral or triple nozzles may be used.

Considering the heating temperature of the object to be heated, the moving speed of the line (when it is continuous), the amount of blowing gas, etc., the temperature of the gas used for spraying is the temperature of the part where the shadow directly receives radiation (desired The heating temperature is set to about the same).

Air is most commonly used as such a gas, but if necessary, an inert gas such as nitrogen gas or carbon dioxide gas may be used, and in some cases steam may be used.

Although the drawing shows an example using gas, liquids such as water, low-melting point inorganic salts, glycols, and mineral oil may be used in place of gas, and the choices are operating temperature, work safety, and It is appropriately determined in consideration of the treatment process and the like.

When a liquid is used as the fluid, recovery equipment is generally provided according to each condition.

In FIG. 2, a blower is used because gas is used as the fluid, but when liquid is used as the fluid, pumps are used instead of the blower.

Further, in FIG. 2, as a method for heating the fluid, a method based on an external heating decision (the heating method itself employs various conventionally known methods) is shown. Since the heating efficiency is high and high-speed and high-temperature heating is possible, the infrared heating device with a reflective surface itself can be used as a device for heating the fluid. This is very important and meaningful.

A typical example thereof is schematically shown in FIG. In FIG. 3, the gas sent from the blower (5) has a predetermined temperature when passing through the flexible tube portion 7 by the radiant heat of the infrared rays radiated from the infrared radiator 2 and collected by the reflective surface 1 in the infrared heating device with a reflective surface. And is blown out from the nozzle 4 as high temperature gas. The heated body 3 moves along the center line of the flexible tube portion.

Thus, according to the method of the present invention, even a molded product having a complicated shape can be uniformly heat-treated without causing uneven heating of the object to be heated.

[Brief description of drawings]

1 to 3 are schematic diagrams showing typical examples of the method of the present invention, and FIG. 4 is a schematic diagram showing a conventional method. FIG. 1: Schematic front sectional view of an infrared heating apparatus with a reflective surface of the present invention (arrows indicate the flow direction of high-temperature gas ejected from a nozzle.) FIGS. 2 and 3: Side sectional schematic view of the same as above FIG. 4: Conventional reflective surface Front sectional schematic view of attached infrared heating device (hatched portion indicates shaded portion with respect to radiation) 1: Reflective surface, 2: Infrared radiator 3: Heated object, 4: Nozzle 5: Blower, 6: Heater 7: Heating coil

Claims (1)

[Claims] 1. A method of heat-treating a molded article by an infrared heating device with a reflecting surface, which has at least one of expansion, contraction, rotation and movement provided in a heating portion of the device, or is fixed. Molding characterized by a high temperature fluid jetting nozzle that blows a high temperature fluid heated to a predetermined temperature to the object to be heated that is a shadow to the radiation from the infrared radiator to heat it uniformly. Infrared heating method for objects.