JPS59186293A - Glass tubular heater with radiation window - 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 This invention relates to a glass tube heater that focuses infrared rays in a desired direction.

(Heater filament inside the glass tube) ・The heated glass tube heater has high efficiency and is practical because the heater filament held in the hollow can raise the temperature of the glass tube. Used as a preferred heater. In particular, if water or hydraulic power falls onto the heater, such as a defrosting heater,
Since the temperature of the glass tube cannot be increased, it is desirable to hold the filament hollow in the glass tube (7) as described above.

However, those that make the filament hollow,
The structural force required to maintain this hollow space is expensive (the disadvantage is that it is expensive).

Therefore, creating a structure in which the entire filament is in contact with the inner surface of the glass tube can reduce costs, but the temperature of the glass tube becomes excessively high, which can cause damage due to thermal shock. I can't make it higher. If the temperature of the filament is not raised, the center wavelength of the infrared light generated will be a long wavelength (for example, 400
43 μm), most of this infrared light is absorbed by the glass tube, and sufficient radiation to the outside cannot be obtained, making it impossible to obtain a practically effective infrared heater.

Therefore, in a glass heater in which the filament is in contact with an entire glass tube, infrared rays are re-radiated from the glass tube by heating the glass tube, and the re-radiated infrared rays are utilized.

This type of glass tube heater has lower costs and more freedom in design (for example, it is easier to design However, as mentioned above, there is a major drawback in that the temperature of the glass tube itself cannot be increased too much. Therefore, in this kind of glass tube heater,
The thermal energy absorbed by the glass tube is converted into radiant energy as efficiently as possible, and the infrared rays emitted from the C glass tube are emitted with condensing properties, making it a light source (heat source) suitable for local heating. However, especially when used as a defrosting heater, it must be resistant to falling water or ice, so it is required to have excellent thermal shock resistance. Ru. Falling water or ice causes evaporation sound on the glass tube surface (especially at 500℃).
In addition to being a problem (which becomes more noticeable as described above), it also greatly affects the life of the glass tube or the treated layer formed on the surface of the glass tube, and furthermore, it takes heat away from the glass tube, causing energy loss.

In view of these problems in the prior art, it is an object of the present invention to provide a glass tube heater having sufficient strength and high efficiency. The overall purpose of the present invention is to provide a filament contact type glass tube heater that has high thermal shock resistance.

The glass tube heater according to the present invention has a heater filament inside a heat-resistant high transmittance glass tube. The filament is disposed in contact with the inner surface of the glass tube, and its main feature is that a mirror layer is formed on the entire surface of the glass tube except for a portion of the side where the filament is in contact.

In other words, the filament is placed in a biased position inside the glass tube, a radiation window is provided on this biased side, and the remaining part is covered with a mirror layer to concentrate the radiant heat energy of the glass tube from the radiation window side.・Since the filament is in contact with a part of the inner surface of the glass tube, the temperature of that part becomes particularly high. Since a radiation window (a portion without a mirror layer) is formed, infrared rays are efficiently radiated from that area, resulting in a highly condensing radiation source.

It's a trench, because the filament is not in contact with the side where the mirror layer is provided, so the temperature in this part is relatively low.
Even if water or ice falls onto this mirror, there will be no problems such as evaporation noise, energy loss, or shortened mirror life.

Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a cross section of a glass tube heater manufactured especially for defrosting, and FIG. 2 similarly shows a partial vertical cross section thereof.

A mirror layer 2 is completely formed on the upper surface of the heat-resistant, high-transmittance glass tube 1, and a small-diameter heater filament 3 is housed therein.The lower part of the heater filament 3 is in contact with the lower inner surface of the glass tube 1. .

The end of the heater filament F3 is electrically connected to the cable wire 5 via the joining fitting 4, and a stop washer 6 is attached to the open end of the glass tube 1, and an insulating plug 7 is attached to the outside of the stop washer 6. is crowned.

As a material for the heat-resistant high-transmittance glass tube 1, for example, "VYCOL J" manufactured by Corning Glassworks, Inc.
High silicate glass such as OR■) is suitable. In addition to this,
High quartz content, such as quartz glass, borosilicate glass (Vilex), aluminosilicate glass, intermediate glass, etc.
High heat resistant high transmittance glass can be used.

(For details on the manufacturing method, properties, etc., see pages 94-102 of the F Glass Handbook published by Asakura Shoten.) The thinner the glass tube I is, the lower the cost. It is desirable because it can increase the
If it is made too thin, the mechanical strength will be insufficient and it will break easily, so it is better to make it as thin as possible considering mechanical strength. The diameter of the glass tube J can be arbitrarily selected depending on the purpose and use. A large diameter is desirable to increase the temperature difference mentioned above, but on the other hand, increases the amount of thermal energy lost as convective losses from the surface of the mirror layer. It is best to select the diameter of the glass tube by considering the balance between mechanical strength, temperature difference, and convective loss5. The material that makes up the entire mirror layer 2 is one that efficiently reflects infrared rays and has high thermal shock resistance. However, considering chemical stability, it is preferable to use all-all substances. This can be formed thinly on the surface of the glass tube 1 by hand painting or printing. For example, if water gold (N-10) manufactured by Inuken Chemical Industry Co., Ltd. is fired to a film thickness of 01 μm or less, the emissivity (ε) at 500'C will be about 004, and the emissivity of the glass tube will be 07 to 08. It can be much lower than that. By changing the area of this low emissivity area (the area where the mirror layer is formed), the glass tube 1
It is possible to change the degree of concentration of thermal energy radiated from the infrared rays. (In Figure 1, 40°~
(within a range of about 180°) As the heater filament 3, a spirally wound nichrome wire or ferrochrome wire with a circular cross section can be used. In particular, it is desirable to wind a ribbon-like nichrome wire or the like into a coil to increase the area of contact with the inner surface of the glass tube 1. The diameter of this heater filament 3 is
It is desirable that the inner diameter of the glass tube 1 is about half to slightly smaller, but more precisely 25 to 80%, preferably l-
A range of 130 to 70% is desirable. If the diameter of the filament 3 becomes too small, sufficient electric power cannot be applied, so it is impossible to make the diameter of the filament 3 too small.

Particularly preferred is about 40 to 69%.

If the wire diameter of the filament 3 is very small compared to the coil diameter (for example, 1/100 or less), the filament F3 will easily deform and become difficult to use. It is necessary to have wire diameter gold.

By roughening the surface of the portion (radiation window) IA of the glass tube l on which the mirror layer 2 is not formed by sanding, chemical etching, etc., the total radiant energy can be increased by about 10%. . That is, by roughening the surface of the glass tube with an abrasive of +2000 to ≠4000, the emissivity of this part can be increased. Since the heater filament 3 is in contact and the mirror layer 2 is formed on the surface of the glass tube, leaving that entire portion, the temperature of the glass tube becomes high in the portion where the filament 3 is in contact, and the mirror layer 2 is formed on the other portions. The infrared rays are reflected and hardly radiated to the outside, and the thermal energy is conducted through the metal inside the tube wall of the glass tube 1 to a portion (radiation window) IA where there is no mirror layer 2, and is radiated from there. Therefore, the heat generated by the filament 3 is efficiently radiated from the radiation window IA of the glass tube 1. That is, the temperature of the glass tube
The temperature is 510° C. on the mirror layer 2 side (the side opposite to the radiation window IA), and the temperature is 380° C. on the mirror layer 2 side (opposite side of the radiation window IA), and infrared rays are effectively radiated from the radiation window IA. (This is because the temperature on the radiation window side is high and the emissivity E is close to 1, while the temperature on the opposite side is low and ε-0.04
(This is because there is an extremely large difference in the temperature and radiation intensity.) The larger the temperature difference on both sides of the glass tube 1, the more efficient and highly concentrated heat radiation can be obtained, so it is preferable. When the temperature increases (for example, 500° C. or higher), it becomes easy to break due to thermal shock resistance, and especially when used for defrosting, there is a problem in that it breaks when splashed with water or ice. Therefore, it is necessary to select an appropriate size for this temperature difference depending on the application.

Various sizes of the glass tube heater of the present invention can be selected depending on the purpose of use.
mm ) and a length of 300 mm ■ “vYCOR” glass tube with a wire diameter of 035 and an outer diameter of 4 m
Fully house the nichrome wire heater (96V/l 40w), place it in the radiation window of about 160° on the side where the heater is fully in contact, and fill the remaining part with water and metal (N~10 manufactured by Inuken Chemical Industry Co., Ltd.)
A material obtained by firing to a thickness of 01 μm is used. In this case, the temperature of the surface of the glass tube on the radiation window side was 510°C, and the temperature of the surface of the mirror layer on the opposite side was 380'C.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of a glass tube heater according to the present invention, and FIG. 2 is a partial longitudinal sectional view thereof. ■ ...Heat-resistant high transmittance glass tube 2 ...Mirror layer 3 ...
... Heater filament IA ... Radiation
Window 4...Joining fittings 5...Cable wire 6...Stonopwasonya 7...
・・・・・・Insulating plug Diagram 1

Claims (1)

[Claims] ■) A heat-resistant, high-transmittance glass tube, a heater filament disposed in contact with a part of the inner surface of the glass tube, and a heater filament in contact with the surface of the glass tube. A glass tube heater with a radiant window, which consists of a mirror layer formed except for a part of the exposed side. 2) The glass tube heater according to item 1 of the scope of Patent No. 8, wherein the heater filament is wound into a coil, and the diameter thereof is 80% or less of the inner diameter of the glass tube. 3) The glass tube heater according to claim 2, wherein the diameter of the coiled heater filament is 30% to 7'0% of the inner diameter of the glass tube. 4) The glass tube heater according to claim 1, wherein the coiled heater filament is ribbon-shaped. 5) The glass according to any one of claims 1 to 4, characterized in that the mirror layer is entirely formed of a metal film having high heat resistance and chemical resistance. Tube heater 6) The size of the mirror layer is such that the circumferential surface of the glass tube is 100°
The glass tube heater according to claim 1, characterized in that the above is covered. 7) The glass tube heater according to claim 1, wherein the surface of the portion of the glass tube on which the mirror layer is not formed is roughened. 8) The roughening treatment of the glass tube costs more than $1000 and several μm.
8. The glass tube heater according to claim 7, wherein the glass tube heater is treated with a diameter abrasive.