JPS61200687A - Handy type heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a simple heater that can be easily and inexpensively manufactured, and particularly relates to a simple heater that can be made relatively thin.

[Prior art] Industrial heaters are generally cast aluminum heaters, which are manufactured by arranging heating element seeds in a mold and pouring molten aluminum over the mold, and heater wires are placed in silicone rubber, etc. An embedded rubber heater, a micro-heater with a structure consisting of only a coated heater wire and used to prevent the liquid in pipes from freezing by wrapping it around piping materials, or a micro-heater that is used to prevent the liquid in pipes from freezing, or by transferring tungsten or the like onto ceramic to generate heat from the tungsten. Ceramic heaters with a structure in which the These heaters can be used depending on the application, i.e.
It is selected as appropriate depending on the temperature conditions, heater installation space, temperature control accuracy required of the heater, etc.

Depending on the application, a thin plate-shaped heater may be required due to relatively high temperature conditions and narrow installation space, and the various heaters described above may not be able to meet these requirements. be.

For example, when extruding molten plastic into a sheet from a die and cooling-molding it on a cooling drum, the distance from the molten plastic discharge part on the underside of the die to the surface of the cooling drum cannot normally be set large in order to maintain molding stability. In order to accurately control the temperature of the molten plastic being discharged to a predetermined temperature uniformly until just before discharge, it is desirable to install a heater on the underside of the mouthpiece. The thickness is required to be, for example, 20 mm or less, the controlled temperature is, for example, 270''C to 300''C, and the temperature control accuracy is good, so it is difficult for the various heaters described above to satisfy these conditions.

[Problems to be solved by the invention: When trying to apply an aluminum casting heater to the lower surface of the mouth for molten plastic mentioned above, the aluminum casting heater is produced using a manufacturing method in which molten aluminum is poured into a mold. Therefore, there is a problem in that it is easy to make products with complicated shapes due to the manufacturing method, but it is difficult to make products with thin plates. Also, 400
In order to pour molten aluminum with a diameter of C or higher, it is necessary to use a thick heater wire that can withstand it, and it is difficult to manufacture a thin plate-shaped heater with a length of 20 m or less.Furthermore, first, a mold is made. As a result, there are problems in that it takes a long time to produce and is expensive.

In addition, with a rubber heater in which the heater wire is buried in a rubber substrate, it is possible to make a relatively thin heater of about 3 mn1 to 51 m1, but since rubber is used, the maximum operating temperature is about 200"C to 230"C. suppressed by
There is a problem in that it cannot be applied to conditions higher than that.

In addition, micro heaters can be wrapped around various shapes like a wire, but there are problems in that contact unevenness tends to occur, which causes temperature unevenness, making it difficult to control a predetermined uniform temperature. be. Moreover, if there are many non-contact parts, in the worst case, only the heater may overheat and break. Further, there is a problem that the handleability of the heater itself and the ease of assembling and disassembling the heater and the object to be heated are poor.

Furthermore, in the case of ceramic heaters, it is possible to manufacture heaters with a high wattage density with a plate thickness of about 3 mm to 5 Ila1, but because they are manufactured through an expensive manufacturing process, for example, 10 tons and 10,000 If the heater is not mass-produced in units of more than one unit, the heater will be extremely expensive, and it is difficult to apply it to a heater that is manufactured as a single item to fit the base, as in the above-mentioned example.

SUMMARY OF THE INVENTION Therefore, the present invention provides an inexpensive simple heater that can be easily manufactured even with a plate thickness of 201111 or less, can be used in a temperature range of 250°C or higher, and can be easily manufactured as a single item. With the goal.

[Means for Solving the Problem] A simple heater of the present invention that meets this objective is provided with a linear passage extending in a direction along the surface of the metal plate in a metal plate, and a heater element is installed in the linear passage. The metal plate is configured as a heating element by inserting a wire therein.

This linear passage is composed of a groove provided on the surface of the metal plate or a small diameter hole bored in the thickness of the metal plate, and if necessary, a plurality of lines are provided in the direction across the metal plate.

Furthermore, the heater wire inserted into the linear passage may be simply held within the linear passage, or the linear passage may be filled with thermocement, etc., and the heater wire is hardened. may be held in an unexposed state.

[Operation] In such a simple heater, the metal plate serving as the heating element is simply provided with a linear passage for inserting the heater wire, so the metal plate may be thin.

In other words, since the heater wire is inserted after the linear passage is formed, the heater wire is not subjected to high temperature history during the manufacturing process, and the heater wire itself does not need to have high temperature durability and can be of a small diameter. The width or diameter of the linear passage may be small, so even if the thickness of the metal plate is small, it can be configured as a heater, and a heater with a plate thickness of about 5a+m can be easily configured. When this linear passage is configured as a groove on the surface of a metal plate, it can be easily formed at the same time as the metal plate is formed or by a normal processing method on a flat metal plate, and is a hole that extends long into the thickness of the metal plate. Even in the case of configuring it as such, it can be easily formed using recent laser processing or the like. If the linear passages are appropriately arranged in the direction along the surface of the metal plate, uniform heat generation can be obtained over the entire predetermined range of the metal plate. Since the surface of the metal plate is made flat or in a shape that follows the shape of the object to be heated, good contact with the object to be heated can be easily obtained, and uniform and accurate temperature control is possible.

Furthermore, since the heater is constructed from the heater wire and the metal plate, the operating temperature range is not kept low as in the case of using rubber or the like, and use at temperatures above 250° C. does not pose a problem.

Furthermore, since the materials used are general-purpose heater wires such as metal plates and small-diameter microheaters, and the linear passages can be easily processed, even negative products can be easily manufactured.

Preferred embodiments of the simple heater of the present invention will be described below with reference to the drawings.

Figures 1 to 4 show a simple heater according to an embodiment of the present invention, and Figures 5 and 6 show the simple heater attached to the bottom surface of a base for extruding molten plastic into a sheet. The case where it is applied is shown.

First, in FIGS. 1 to 3, reference numeral 1 indicates a flat metal plate, the thickness of which is set, for example, in the range of 3u+ to 20+1i1 depending on the application. When used as a heater for attachment to the bottom surface of the cap shown in FIGS. 5 and 6, which will be described later, it is desirable that the wall thickness be as thin as 3 mm to 6 g 1 l. The material of this metal plate 1 is not particularly limited, but from the viewpoint of heat transfer efficiency and temperature control, it is preferably a material with as high thermal conductivity as possible, such as aluminum or copper.

The metal plate 1 has a linear passage 2 extending in a direction along its surface.
is provided. The linear passage 2 is formed by providing a long groove on the surface of the metal plate 2, or by providing a small diameter hole extending long in the direction along the surface within the thickness of the metal plate 1.

This small-diameter hole can be easily formed by laser processing, which has become commonly used in recent years. In this embodiment, the linear passage 2 includes a relatively wide groove 3 on one surface of the metal plate 1 and extending long in the direction along the surface of the metal plate 1, as shown in FIG.
It consists of a suitable number of small diameter holes 4 arranged on the bottom side of the groove 3 and extending in the direction in which the groove 3 extends. Then, a heater wire 5 whose surface is coated and insulated is inserted into the hole 4. After inserting the heater wire 5, thermocement 8 is filled from the groove 3 side,
After filling, the surface of the thermocement 8 is smoothed to match the surface of the metal plate 1.

As the heater wire 5, for example, a commercially available micro heater or the like is used, and the specifications of the heater wire 5 are determined depending on the application, but in the case of a heater for mounting on the bottom surface of the cap, which will be described later, for example, the JI diameter of the heater is 1. , 61I11 degree, operating temperature 3
It is desirable to select a heater wire 5 having a specification of about 00°C.

The heater wires 5 are connected, for example, as shown in FIG. 4, and AC voltages V+ and V2 are applied to the terminal sides. By arranging the heater wires 5 in this way, the metal plate 1 is configured as a heating element, but the capacity and watt density of the heating element are determined by the specification selection of the heater element a5 and the arrangement of the heater wire 5. Can be set arbitrarily depending on the density. The heater wire 5 is connected to a connector 6 attached to the end of the metal plate 1, and a voltage is applied through the connector 6. The connector 6 is connected to a suitable control device (not shown), and the applied voltage, applied current, applied time, or a combination thereof is controlled by the control device, and the heat generation of the metal plate 1 is controlled.

Note that 7 indicates a screw hole for attaching the metal plate 1 to an object to be heated.

Further, in this embodiment, the linear passage 2 is composed of the groove 3 and the small diameter hole 4, but it is also possible to provide a method in which only a groove for inserting the heater wire is provided on the surface of the metal plate, or within the thickness of the metal plate. For example, the linear passage may be constructed by providing only small diameter holes extending in the longitudinal direction of the metal plate.

Next, the operation of the simple heater configured as described above will be explained below.

Since the heater element 115 extends over almost the entire length of the metal plate 1, the metal plate 1 is heated almost uniformly over the entire surface. Moreover, in this embodiment, since the heater element 15 is hardened with thermocement after insertion, the heat conduction from the heater element 5 to the metal plate 1 is maintained in a good state, and the metal plate 1 itself is also heat conductive. Since the metal plate 1 is made of a material with a high heat exchange rate, heat is generated uniformly.

Furthermore, since the heater wire 5 is inserted after the linear passageway 2 is formed, the heater wire 5 does not suffer from high temperature skin during the heater fabrication process, and a small diameter heater wire 5 itself is sufficient. Therefore, the cross-sectional area of the linear passage 2 can be small as shown in the figure, and the thickness of the metal plate 1 can be made small after all, and a thin-walled heating element can be easily manufactured.

In addition, since the gold plate 1 can withstand high temperatures compared to rubber etc., it can be used at temperatures of about 250'C to 300'C.
The degree of heating element is problematic (manufactured.

The capacity, wattage density, etc. of the heating element can be set arbitrarily to some extent by appropriately setting the number of small diameter holes 4 or by reciprocating the heating element, and the thin plate heater can be adjusted according to the application. easily obtained.

Next, a specific application example of the simple heater configured as described above will be explained.

5 and 6 show a simple heater according to the present invention,
An example is shown in which the device is attached to the bottom surface of a mouthpiece 10 that discharges molten plastic in the form of a sheet. Molten plastic is discharged in a sheet form from the slit-shaped discharge port 11 of the cap 10 onto a cooling drum (path shown) below, but the dimension between the cap 10 and the cooling drum is usually kept small due to molding problems. , it is not possible to install a large heater between them. On the other hand, the sheet-shaped molten plastic is kept at a predetermined temperature (for example, 270°C to 300°C) until just before being discharged from the nozzle 10.
'C) It is desired that the system be controlled by

However, generally, an adjustment bolt 12 for adjusting the slit gap of the discharge port 11 is provided on one side of the lower part of the mouthpiece 10.
are arranged in the longitudinal direction of the base 10.

On the upper side of the base 10 and on the opposite side from the adjustment bolt 12,
For example, it is possible to install an aluminum cast heater 13 or the like, but it is difficult to install it on the adjustment bolt 12 side. Therefore, at the bottom of the base 10, the adjustment bolt 1
The temperature on the second side becomes lower than the temperature on the opposite side, and the temperature difference is 20°C with respect to the target control temperature (for example, 290°C).
It can reach up to 30″C.

As described above, the simple heater according to the present invention can be manufactured with a thin wall and has good temperature control, and can be installed between the cooling drum and the lower surface of the base 10. Therefore, as shown in Figs. 5 and 6, a heater similar to that shown in Fig. 1 was installed to improve the temperature distribution of the base 10.The heater rating was 200V,
A 1260W heater was selected and 120V was applied to this heater. As a result, it became possible to accurately control the target temperature of 290° C. on both the adjustment bolt side and the opposite side of the lower part of the cap 10, and it was possible to eliminate the temperature difference.

[Effects of the Invention] As explained above, when using the simple heater of the present invention, linear passages extending in the direction along the surface of the metal plate are provided,
Since the heating element is constructed by inserting the heater wire into the linear passage, it is possible to easily manufacture a thin heater with a uniform temperature with a wall thickness of about 3++++n to 201f11, and the temperature is 250°C or higher. It can be used without problems even at temperatures of
Moreover, since general-purpose products can be used as the component parts, it is possible to obtain an extremely practical simple heater that can be easily manufactured as a single item at low cost.

[Brief explanation of drawings]

FIG. 1 is a plan view of a simple heater according to an embodiment of the present invention, FIG. 2 is a side view of the device in FIG. 1, and the third section is an enlarged sectional view taken along the line ■-■ in FIG. Section 4 is the heater wiring diagram of the device shown in M1, Fig. 5 is a schematic side view of the area around the cap when the simple heater shown in Fig. 1 is attached to the bottom of the cap, and Fig. 6 is the part of the device shown in Fig. It is an enlarged sectional view. 1... Metal plate 2... Linear passage 3... Groove 4... Hole 5... Heat silicon G...・・Connector 8・・・・Thermocement・ 5 Hiita Sokatsu Figure 5 Figure 6

Claims (1)

[Claims] (1) The metal plate is configured as a heating element by providing a linear passageway extending in a direction along the surface of the metal plate and inserting a heater wire into the linear passageway. A simple type heater.