JPH01135527A - Steam generating body and production thereof - Google Patents

Abstract

PURPOSE:To enable rise in temp. of foodstuffs without limiting a place and enclosing an incomplete reacted mixture consisting of iron powder, water retention substance, water and chloride in an air-permeable packaging material. CONSTITUTION:A mixture consisting of iron powder, water retention substance, water and chloride is allowed to react under the coexistence of air until temp. reaches about 90 deg.C and the produced incomplete reacted mixture is cooled and thereafter enclosed in an air-permeable packaging material to obtain a steam generating body. The specific area of iron powder is preferably regulated to >=0.5m<2>/g. As water retention substance, zeolite and fibrous substance, etc., are used. As chloride, NaCl and CaCl2, etc., are used and the loadings preferably are 0.002-0.1mol. for 100pts.wt. iron powder. Further the loadings of water are 15-60pts.wt. for 100pts.wt. iron powder and preferably regulate to amount of 0.8-1.5 times these of water retention substance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a steam generator and a method for producing the same, and is mainly applicable to simply heating or keeping foods warm.

[Prior Art] It would be very convenient if various foods could be easily heated or kept warm anytime and anywhere, and such demands have been increasing in recent years.

Conventionally, methods have been proposed that utilize the heat of hydration generated by adding water to quicklime to meet these demands. This method involves tearing a bag filled with water using a needle or other means such as pulling a string that has been fixed in advance, and causing the outflowing water to react with quicklime set separately. It utilizes the heat generated by

Also, in recent years, disposable hand warmers have been widely used, which are made by mixing iron powder with a specific surface area of 0.2 TrL2/g or less and a water-retentive material impregnated with an aqueous chloride solution, and packaging this mixture in air-permeable packaging. When used, the iron powder is thoroughly massaged to induce an oxidation reaction of the iron powder, and the WA degree of the generator is maintained at a maximum of 60 to 70°C in the pocket.

[Problems to be solved by the invention] Currently proposed heating elements that utilize the heat of hydration of quicklime have a low heat of hydration of 20 kcal/■01, and in order to secure the necessary amount of heat, multiple units are required. It has the drawback of being bulky and requiring use. In addition, the quicklime used has strong water absorption, so when the heating element is stored, it absorbs atmospheric humidity, or when it is packed together with food, the moisture in the food is taken away, causing the heat-generating layer of the quicklime to deteriorate. Due to these problems, it is difficult to easily use it as a heating element for raising and retaining the temperature of a wide range of foods.

In addition, disposable hand warmers utilize the oxidation heat of iron powder as mentioned above, but this heating element is used in the process of thoroughly loosening the iron powder.
60-70 for the first time under the condition of being kept warm by body temperature in the pocket.
℃, but with this level of activity it is not possible to heat food in a short time, and it is difficult to keep food warm for a long time at various atmospheric temperatures.

The present invention eliminates the deficiencies of the conventional methods and provides a steam generator that is easy to handle and store, and can easily raise the temperature of food in a short time and keep it warm for a long time.

[Means for Solving the Problems] In order to improve the problems of the prior art as described above, the present inventors conducted tests and studies on the heating conditions of iron powder over a long period of time, and found that the heating element that generates water vapor is The present invention was achieved based on the discovery that this method is effective in raising the temperature, maintaining heat, and ensuring safety.

That is, the present invention is characterized in that a mixture consisting of iron powder, a water-retaining substance, water, and chloride is mixed to generate heat in the presence of oxygen gas (for example, air), and after cooling, the mixture is enclosed in a breathable packaging material. It is a water vapor generating body. More specifically, iron powder whose main component has a specific surface area of 0.5 m2/g or more, and iron powder 10
O, ()02 to 0.1 mol of chloride per 0 parts by weight,
and 15 to 60 parts by weight of water per 100 parts by weight of iron powder,
The water-added layer mixes and generates heat in the coexistence of oxygen gas with a water-retaining substance whose amount is equivalent to 0.8 to 1.5 times the amount of water absorbed by the water-retaining substance, and after cooling, the mixture is made into a breathable packaging material. It is characterized by being enclosed.

The iron powder used in the present invention has a specific surface area of 0.5TrL2
/g or more, but such iron powder is produced by heating iron oxide powder to 50% by reducing gas such as H2 or CO.
It is obtained by reducing the metallicity to 50 to 95% at 0 to 900°C.

Iron powder with a specific surface area of 0.5 m''/g or more and a metal content of nearly 100% can naturally be suitably used in the present invention, but problems arise in terms of economic efficiency. Further, iron powder having a specific surface area of 0.5 m''/9 or less does not provide the activity necessary for the present invention, and is disadvantageous in terms of temperature increase rate.

The chlorides used in the present invention include NaCl, CaCl, M
QCJ! Alkali and alkaline earth chlorides such as 1, as well as FeCl2, FeC1, ZnC1, AICj!
3 and VC13, all of which are effective in activating iron powder to approximately the same extent, but MQCJ! , Na11 and ZnC12 can be suitably used in the present invention.

The amount of chloride added necessary for the present invention is as described above, 10% of iron powder.
The amount is in the range of 0.002 to 0.1 sol per 0 parts by weight, and if it is less than 0.002 mol, it is not possible to sufficiently activate the iron powder, and if it is added in an amount of 0.1 mol or more, it is not possible to activate the iron powder. However, smooth water movement does not occur during the oxidation reaction of the iron powder, and in either case, the temperature increase rate necessary for the present invention cannot be obtained.

Furthermore, the same effect can be expected when adding chloride either in solid form or in aqueous solution.

In the present invention, the appropriate amount of water to be added is 1 iron powder as described above.
The amount is 15 to 60 parts by weight, but if it is less than 15 parts by weight, the sustainability of the oxidation reaction will decrease, and if it is more than 60 parts by weight, the sustainability of the oxidation reaction will be satisfied, but the oxidation reaction rate will be lowered. tends to decrease, which is not suitable for the purpose of the present invention.

Water-retentive substances used in the present invention include activated carbon, zeolite, and fibrous substances, among which activated carbon has excellent water absorption properties and can be optimally used in the present invention.

In the present invention, the water-retaining substance is a humidity regulator necessary for the iron powder to sense oxygen gas and promptly start the oxidation reaction, and at the same time, it prevents the oxidation reaction from moisture volatilizing from the surface of the iron powder due to the heat of oxidation. It has the role of supplying supplies until the end.

When using a water-retaining substance with a small amount of water absorption, it is necessary to mix a large amount of the water-retaining substance into the iron powder layer in order to coexist with a predetermined amount of water, and as a result, the iron powder content decreases.
This results in the disadvantage that the heat generation temperature, heat generation rate, etc. decrease. Moreover, water-retaining substances with strong water-absorbing power such as silica gel cannot smoothly replenish the water necessary for the oxidation reaction of iron powder, and are therefore unsuitable as water-retaining substances for use in the present invention.

As described above, the mixture prepared under conditions suitable for the present invention still has insufficient activity as it is, but the activity required for the present invention can be obtained by sufficiently mixing and generating heat in the presence of air. As for the mixer used here, a rotary mixer such as a cement mixer, a Tally kiln, or a V-shaped mixer is preferably used, but in any case, the space of the mixer is replenished with air or oxygen gas to mix the mixture. It is necessary to continue mixing until the temperature reaches about 90°C or higher. In this case, about 90% of the mixture is in an unreacted state. If the mixture generates insufficient heat during mixing, even if the mixing ratio of each component is appropriate, the amount of heat and rate of heat generation required for the present invention cannot be obtained.

As described above, the water vapor generator of the present invention is completed by enclosing the mixture prepared under appropriate conditions in an air-permeable packaging material after cooling. When the steam generating body of the present invention comes into contact with air, it immediately starts to generate heat, and then steam starts to be generated, allowing the enclosed product to be heated efficiently. In particular, when it is desired to raise the temperature of a product in a short time, it is desirable to improve the contact efficiency between iron powder and oxygen gas. It is preferable to encapsulate a heat generating agent, and when the purpose is to keep warm for a long time, the Gurley type air permeability is 10 to 100 sec/
^1rload packaging material is used, ventilation m is i, 1jt
It is effective to use illuminating methods.

The steam generator of the present invention produced as described above has 0
．． It has a calorific value of 6 to 1.0 cal/90, and the amount of exothermic agent enclosed can be determined depending on the purpose of use, making it possible to easily manufacture products with any capacity.

[Example] Example 1 Specific surface area 1. ．． 3m2/g, metal degree 68%, particle size 15
100 g of iron powder of 0 mesh or less and activated carbon 309 with a water absorption of 0.8 d/9 were weighed into a Bolibu O pyrene film bag with a capacity of about 31, and 20.007 mol of MgCj and 30 d of activated carbon were weighed out.
of water was added, the bag was opened and heated for a few minutes (Brahma heat U), and the same operation was repeated twice with the air added to heat up to 97°C. After cooling by cutting off the air, the mixture was heated. 35
9 to Gurley type composite wire 1fJ cloth with air permeability 6 sec/Air 100ae. Dimensions: Width 70m/m, Length 12
It was sealed in a 3-sided seal in the form of 0 m/m.

One more batch was made using the same procedure, and the second batch was packed in nylon film and stored.

Test Example 1 A circular styrofoam container with a bottom surface of 120 ra/mφ, a top inlet of 180 m/mφ, and a height of 50 m/m has 9 7 m/m φ cut holes in the center of the bottom and 5 7 m/m φ holes in the center of the word.
The container was used as a test container.

Two steam generators of Example 1 were placed in parallel at the bottom of a test container, and a bottom surface of 110 nm/mφ and a travlene of 16
An aluminum container with a diameter of 07 FL/7 Wφ and a height of 20 m/7 FL was placed, 100 d of water was put into the aluminum container, the test container was covered, and the temperature change of the 100 d of water was measured. The results are shown in Table 1, and the water temperature reached 70°C after 10 minutes.

Table 1 Examples 2 to 8 Steam generators of the present invention were produced in the same manner as in Example 1 except that the specifications of the iron powder were changed. Furthermore, the temperature change of 100 d of water was measured for each steam generator in the same manner as in Test Example 1.

The results of Examples 2 to 8 and Test Examples 2 to 8 are shown in Table 2.

As is clear from Table 2, iron powder with a larger specific surface area can raise the water temperature higher within the same time, but 0.57
When iron powder of approximately FL2/9 was used, the rate of temperature rise of water was considerably reduced.

Examples 9 to 16 Steam generators were produced in the same manner as in Example 1 except that the type and amount of chloride added were changed. Furthermore, the temperature change of 100 d of water was measured for each steam generator in the same manner as in Test Example 1. These results are shown in Table 3.

Examples 17 to 25 Steam generators were produced in the same manner as in Example 1, except that the amount of water added, the type of water-retaining substance, and the amount of water-retaining substance added were changed. Also, for each steam generator, the same procedure as in Test Example 1 was carried out to obtain 100 ai of water! The temperature change was measured.

The results of Examples 17-25 and Test Examples 17-25 are shown in Table 4.

Comparative Example 1 Specific surface area is 0.13 m2/! A steam generator was produced in the same manner as in Example 1 except that iF iron powder was used. Moreover, the temperature change of 100Ile of water was measured in the same manner as Test Example 1 (Test Example 26).

Comparative Examples 2 and 3 Steam generators were produced in the same manner as in Example 1, except that the amount of MoCl3 added was outside the specified value of the present invention. In addition, water 100% was added to each steam generator in the same manner as Test Example 1.
The temperature change of d was measured.

The results of Comparative Examples 2 and 3 and Test Examples 27 and 28 are shown in Table 5.

Comparative Examples 4 and 5 Steam generators were produced in the same manner as in Example 1, except that the amount of water added was outside the specified value of the present invention. Furthermore, the temperature change of 100 d of water was measured for each steam generator in the same manner as in Test Example 1.

The results of Comparative Examples 4 and 5 and Test Examples 29 and 30 are shown in Table 5.

[Effect of the invention] The steam generator of the present invention has the following effects.

(1) The calorific value per unit ff1ffi is large, and the steam generator is compact. (2) It is easy to operate because it generates heat upon contact with air. (3) Heat transfer efficiency is high because water vapor serves as the heat medium. (4) It is safe because it is a heating element that contains water.

Due to the above-mentioned advantages, the steam generator of the present invention can be widely used as a heating element that can raise the temperature of food anytime and anywhere.

Substitute person Asa Mura Hao

Claims (10)

[Claims] (1) A steam generator comprising an incompletely reacted mixture of iron powder, a water-retentive substance, water and chloride enclosed in a breathable packaging material. (2) The specific surface area of the iron powder is 0.5 m^2/g or more,
A steam generator according to claim 1. (3) Chlorides are NaCl, CaCl_2, MgCl_2
, FeCl_2, FeCl_3, ZnCl_2, AlC
A steam generator according to claim 1, selected from the group consisting of l_3 and VCl_3. (4) The amount of chloride added is 0.0 per 100 parts by weight of iron powder.
02-0.1 mole of water vapor generator according to claim 1. (5) The water vapor generator according to claim 1, wherein the water-retaining substance is selected from the group consisting of activated carbon, zeolite, and fibrous substances. (6) Reacting a mixture consisting of iron powder, water-retaining substance, water and chloride in the presence of air until the temperature reaches about 90°C,
A method for producing a steam generator, which comprises cooling the generated incomplete reaction mixture and then encapsulating it in an air-permeable packaging material. (7) The specific surface area of the iron powder is 0.5 m^2/g or more,
A method according to claim 6. (8) Chlorides are NaCl, CaCl_2, MgCl_2
, FeCl_2, FeCl_3, ZnCl_2, AlC
7. The method of claim 6, wherein the method is selected from the group consisting of l_3 and VCl_3. (9) The amount of chloride added is 0.0 per 100 parts by weight of iron powder.
7. The method of claim 6, wherein the amount is 0.2-0.1 mol. (10) The amount of water added is 15-6 per 100 parts by weight of iron powder.
0 parts by weight and 0.8-1 of the water absorption amount of the water-retaining substance
．． 7. The method of claim 6, wherein the amount is 5 times.