JPH0311583A - Plane-form heat generator and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a plane-form heat generator which can be formed easily at a job site by using a formation of a limesilicate type hydraulic substance to which carbon fiber chops are dispersed and mixed. CONSTITUTION:To a limesilicate type hydraulic substance powder, 1-4wt.% of carbon fiber chops with the length 1-12mm are added and mixed in the condition being dried up substantially. By adding the water, kneading, and giving a form to a material prepared in such a way at a job site, an adequate product is obtained. The formation is a plane-form body with the thickness less than 10mm generally, and it can be formed easily by a process such as a troweling, a spray coating, or a roller painting. Copper electrodes 2 are buried with 10cm spacing at the middle of the thickness of the heater thus obtained to form a plane-form heat generator.

Description

Detailed Description of the Invention [Object of the Invention] The present invention relates to a planar heating element and a method for manufacturing the same, and provides a planar heating element and an advantageous manufacturing method thereof that are suitable for use in snow melting, floor heating, etc. This is what I am trying to do.

(Industrial application field) Surface heating elements for snow melting and heating using floors or walls, and their manufacturing technology.

(Conventional technology) Planar heating elements for snow melting and heating are made by mixing carbon powder with resin and molding it into a thin layer, or by installing pipes on floors or walls to generate boiling water or high-temperature heat. Some of the known types include those in which the medium is circulated, and those in which a heating element such as a nichrome wire is embedded in the wall or floor.

Furthermore, various manufacturing methods and construction methods regarding the above-mentioned surface heating elements are also known.

(Problems to be Solved by the Invention) In the conventional products as described above, concrete or mortar is used to protect the heat radiator or provide insulation, especially when used on floors or pavement surfaces. etc., and it is necessary to sandwich it preferably in a sandwich-like manner, and the construction and maintenance are complicated, the number of man-hours is large, and the cost is high.

Therefore, the construction location is limited, and it is difficult to use the construction site, for example, on the road.

``Structure of the Invention'' (Means for Solving the Problems) The present invention has been devised through intensive research to achieve the objects stated in 1. A planar heating element is used in which 1 to 4% by weight of chopped carbon fibers having a length of 3 to 121 mm are evenly dispersed and mixed in the body, and the heating element is kneaded with a liquid and then heated with a iron. It has been found that the above-mentioned problems of the conventional products can be solved by manufacturing by molding and curing by layering techniques such as painting, blowing, or roll pressing.

(Function) By using carbon fibers with a length of 3 to 10 mm, it is possible to appropriately obtain a dispersion mixture similar to powdered silicate-lime-based hydraulic substances, and with an appropriate amount of mixture, the carbon fibers can conduct contact with each other to generate heat. I'll get it. If the length is less than 3ffi1, a large amount of blending is required to obtain mutual contact between the carbon fibers, and the desired heat generating effect cannot be obtained accurately. On the other hand, carbon fibers with a length longer than IQam have a strong tendency to entangle each other, so that they can be evenly mixed with silicate lime powder, and the heat generation state tends to be uneven. There is. If the amount of carbon fiber is less than 1 wt%, even if uniform mixing is obtained, the amount of carbon fiber blended is so small that proper contact between the fibers cannot be obtained and heat generation is insufficient.

If the carbon fiber content exceeds 4%, the cost increases and there is a remarkable tendency that the necessary heat generation will not be generated.

By adding and mixing carbon fiber to the silicate lime hydraulic substance powder in a substantially dry state, the mixing is facilitated and uniform mixing is appropriately obtained. An appropriate product can be obtained by kneading and kneading the thus prepared product with water at the construction site. Molding generally has a thickness of 1
It is a planar body with a thickness of 0 mm or less, and can be easily formed by methods such as troweling, blowing b-1, or roller coating.

Of course, the product according to the present invention as described above can obtain the desired product through factory production, but a preferred method is to combine the above-mentioned lime silicate hydraulic substance powder and carbon fiber material in a factory. The mixture is prepared in a dry state, packed in bags, and transported to the construction site where water is added and kneaded for construction. In other words, it is not easy to uniformly mix the carbon fiber material and the silicate lime hydraulic substance powder as described above, and it is not possible to achieve a preferable uniform mixing by hand, but by using a special combing mechanism, etc. The homogeneous mixture thus formed can be effectively dispersed and mixed with the powder in this dispersed state using factory equipment, and the homogeneous mixture thus formed can be used for cargo handling,
Since the mixed state does not change even during transportation, construction can be easily carried out by simply adding water and mixing at the construction site. In this way, the desired construction can be completed in a single process at the site without the need for a double process of molding and manufacturing at the factory and then working at the construction site.

The above-mentioned carbon fibers have a diameter of 5 to 20 μm and a length within the above-mentioned range, and may be either pitch-type or bread-type, but should be resistant to electrical loads at the points of contact between the fibers. Graphitized hydrocarbons are preferred.

(Example) Specific examples of the present invention will be described below.

Example 1 A carbon fiber material having a typical length of 6 mm was provided, and the amount of this carbon fiber material added to cement mortar made of ordinary Portland cement was set to three types: 1 wt%, 2 wt%, and 4 wt%. The thin protrusions provided the material between the drums, and one drum was rotated at a low circumferential speed of 1200 cm/min and the other drum was rotated at a high circumferential speed of 50000 cm/min. While the tangled aggregate of carbon fibers is defibrated by the action, the sand-cement ratio is made 1:1, and it is sequentially added and mixed into the dry powder, and in this way, the carbon fibers are mixed in an approximately even distribution. The mixture was kneaded with water to obtain a heating element as a mortar molded plate 1 with length and width of 30 cm and thickness of 51I+1 as shown in FIG.

Copper wire electrodes 2 were set in the middle of the heating element 1 in the thickness direction so that the interval was 10 cm, and the resistance value between the electrodes 2 and 2 and the heat generation We investigated the situation. The measuring device used was a battery-powered insulation resistance meter manufactured and sold by Yokogawa Electric, and the measurement results were as shown in Table 1 below.

Table 1 Note that the heat generation status was checked for both 5■ and 10■, but in both cases, heat generation was not substantially observed at 1d% and 1wt%, which indicates that conductivity was good at 4ivt%. It is recognized that this is due to the fact that the carbon fiber length is too low and does not generate heat, and in the case of 1wt%, the conductivity is so poor that no heat is generated.In the case of this carbon fiber length of 6111, the maximum heat generation was obtained at around 2tvt%. It was confirmed that heat generation was reduced both when the amount added was increased and when it was decreased.

In addition, when carbon fiber length longer than 61 is used, the maximum point of heat generation can be obtained at a lower addition amount than the above, and on the other hand, when carbon fiber is shorter than 61, it is necessary to add more. It has also been confirmed that the maximum point of heat generation cannot be obtained unless the mixing amount is - In the case of carbon fiber of 3 to 1.0 I learned that a substantially preferable heating element can be obtained as follows.

Example 2 As mentioned above, preferable heat generation properties can be obtained by mixing 2wt% of standard length 61 mm carbon fibers.In order to study the details of the heat generation state, a vertical and horizontal structure as shown in Fig. 2 was used. Heating elements each 20 cm in thickness and 5 cranes in thickness were manufactured from 2 wt% of 611 carbon fiber, with 10 cm intervals in the center.
Two electrodes 2.2 were arranged. However, regarding such a heating element 1, as shown in FIG.
The surface temperature was measured using three measurement points, designated as No. 1 to No. 3, and three measurement points obtained in the same manner as above at the intermediate position between the picture electrodes 2 and 2, as No. 1Ik14 to No. 6. That is, each heating element 1 is housed in a constant temperature room at 20°C, and the picture electrode 2
．． When the temperature of the heating element 1 became constant after 1 hour had passed since 15V and 20V were applied between the two, the temperature was measured at the measurement points No. 1 to No. 6 as described above, and the temperature was 15.
In the case of electrification (2), the positive 3 measuring point showed 30°C, while the positive 5 measuring point showed 40.5°C, and the other measuring points south 1, 2, 4 and Number 6 showed intermediate measurements between them. That is, the heat generation distribution range of the measurement results was about 10°C.

On the other hand, for the same test specimen as above, the applied voltage was 20
In the case of V, the M3 measurement point is 59.5°C, the floor 4 measurement point is 69°C, and the other temperature values are between them, and even in this case, the temperature is distributed within a range of about 10°C. It is known that the heat-generating sheet body is practically preferable.

Example 3 2wt% carbon fiber with a length of 4 to 10mm (average 6mm)
The snow melting test was carried out outdoors using a mortar with the same composition as in Example 1.2, and the lowest temperature was 0°C to 8.8°C. The results are shown in Table 2 below. Ta.

It has been confirmed that accurate snow melting can always be achieved under conditions where temperatures reach as low as -8.8°C and snowfall amounts reach 2 to 11 cm. Note that as shown in Table 2 above, the applied voltage is 1.0.
When conducting an intermittent test with the setting set to IV, the current value when the heating element surface is wet is 0.6 A,
On the other hand, in a dry state, a small difference of 0.57A was observed.

"Effects of the Invention" According to the present invention as explained above, a heat generating material that efficiently utilizes carbon fiber can be provided easily and at low cost, and it can be advantageously used not only for indoor heating but also for snow melting purposes. This is an invention that has great industrial effects.

[Brief explanation of the drawing]

The drawings show specific embodiments of the present invention, and FIGS. 1 and 2 each show an oblique view of a molded body in accordance with an embodiment of the present invention. However, in this drawing, 1 represents a heating element and 2 represents an electrode. ■

Claims (1)

[Scope of Claims] 1. A molded body made of lime silicate hydraulic material has a length of 3 to 3.
A planar heating element characterized in that 1 to 4% by weight of chopped 12 mm carbon fibers are evenly dispersed and mixed. 2. 1 to 4% by weight of chopped carbon fibers with a length of 3 to 12 mm are added to silicate lime hydraulic material powder evenly dispersed therein, then liquid is added and kneaded, and then applied with a trowel, sprayed, or rolled. A method for manufacturing a planar heating element characterized by molding and curing using a layering method.