EP2179229A2

EP2179229A2 - Chemical heating compositions and methods

Info

Publication number: EP2179229A2
Application number: EP08781270A
Authority: EP
Inventors: Michael Sheppard Bolmer; Cullen M. Sabin
Original assignee: Tempra Technology Inc
Current assignee: Tempra Technology Inc
Priority date: 2007-07-03
Filing date: 2008-07-02
Publication date: 2010-04-28
Also published as: JP2010532463A; WO2009006521A3; WO2009006521A2

Abstract

A user-activatable, single-use chemical heater that includes at least one compartment of a first type separated from at least one compartment of a second type by a separator that is compromisable by a user to establish communication therebetween. Water and ingredients of a heating system that generates heat by an oxidation-reduction reaction between aluminum metal and a water-soluble copper halide are stored in and divided between the compartments of the first and second types so as not to initiate the heat-generating reaction until the contents of the compartments of the first and second types mix following compromise of said separator.

Description

CHEMICAL HEATING COMPOSITIONS AND METHODS

Cross-Reference to Related Application

This application claims the benefit of and priority to U.S. Provisional Patent Application Serial Number 60/947,876, filed on July 3, 2007, the disclosure of which is hereby incorporated herein by reference in its entirety.

Technical Field

This invention relates to heating compositions for user-activatable, single-use chemical heaters and heating methods employing such compositions.

Background

Single-use chemical heaters that are activatable by a user are used to heat a wide variety of things, such as food and beverages, body parts of humans and animals, and solid, liquid or semi-solid objects and compositions. Such heaters have shapes and constructions designed for specific uses. A heater may comprise, for example, a self-heating cup or container for beverages, such as disclosed in published international patent application WO 2005/115872, published international patent application WO 03/096855, United States patent 6,481,214, and United States patent 3,874,557. A heater may be tray-like for heating food, such as disclosed in United States patent 4,809,673. A heater may be in the form of a flexible heat pack adapted to heat body parts or objects, including pouched food such as military meals commonly referred to as meals ready to eat (MRE's), such as shown in United States patent 6,640,801.

User-activated heating systems for single-use chemical heaters include calcium oxide systems, in which calcium oxide is mixed with, and reacts with, water to generate heat, as described in United States patent 5,809,786; permanganate heating systems, in which an alkali metal permanganate oxidizer is mixed with, and reacts with, a fuel such as glycerol (in aqueous form) to generate heat, as described in United States patents 5,035,230 and 5,984,953. Heating systems described in the literature also include systems in which a powdered active metal such as zinc or magnesium, is mixed with, and reacts with, water to generate heat, as described in international patent application WO 97/06391, and systems in which a combination of powdered copper sulfate, zinc, and magnesium is mixed with, and reacts with, water to generate heat, as disclosed in Russian patent RU 2 271 972.

Summary

This invention includes single-use chemical heaters that include water-activated heating systems that utilize the oxidation-reduction reaction between aluminum metal (Al) and a water- soluble halide salt of copper, either anhydrous or hydrated, such as copper chloride, preferably copper chloride hydrate, CuCl₂^H₂O. The copper halide salt may be included as a starting material, alone or in combination with other copper salts, such as sulfate (CuSO₄-5H₂O), that are converted to copper halide during the heating reaction with aluminum metal and water. Alternatively, the soluble copper halide can be generated in the reaction mixture by the reaction between such a nonhalide copper salt, for example copper sulfate, and a non-copper water- soluble halide salt, that reacts with the nonhalide copper salt in water to produce the copper halide, for example copper chloride, that then reacts with aluminum metal in water to generate heat. In this specification, including the appended claims, we refer to a non-copper, water- soluble halide salt that is capable of reacting with such a nonhalide copper salt in water to produce a copper halide as a "halide salt catalyst," or, for short, simply as "catalyst". Halide salt catalysts are water-soluble halides. Examples of suitable halide salt catalysts include non-copper metal halide, preferably alkali metal halides and alkaline earth metal halides such as sodium chloride (NaCl), potassium chloride (KCl), sodium bromide (NaBr), potassium bromide (KBr), calcium chloride (CaCl₂), magnesium chloride (MgCl₂), calcium bromide (CaBr₂) and magnesium bromide (MgBr₂). Hydrogen chloride (HCl) is also a suitable catalyst. Halide salt catalysts also include mixtures of two or more of such halide salts.

Mixing a nonhalide copper salt, such as copper sulfate, and aluminum metal in water produces no heat. Adding even a small amount of either copper halide salt or halide salt catalyst, or both, to this mixture produces approximately as much heat as if all the copper salt were copper halide. This suggests that the halide ions are catalysts for the reaction of copper ions and aluminum metal. In embodiments utilizing a nonhalide copper salt, preferably copper sulfate, in combination with copper halide or halide salt catalyst, the relative amount of copper halide or catalyst to nonhalide copper salt can be varied to modify the rate of heat generation. In embodiments utilizing halide salt catalyst, addition of a water-soluble acetate salt such as sodium acetate, for example as sodium acetate trihydrate (NaC₂H₃O₂-3H₂O), has been found to increase both the rate and amount of heat generation, even though sodium acetate is itself ineffective as a catalyst according to this invention. We refer to sodium acetate as a "catalyst activator." It is expected that related compounds will perform similarly and may be substituted for sodium acetate.

For use in heaters of this invention, the form of aluminum metal can be varied to modify its surface area and overall structure so as to modify the rate and completeness of the heat- generating reaction.

Suitable nonhalide copper salts for use with copper halide can be tested routinely by substituting them for copper sulfate in the heating composition of Example 3 below. Similarly, suitable nonhalide copper salts for use with catalyst can be tested routinely by substituting them for copper sulfate in the heating composition of Example 5. Suitability of a particular nonhalide copper salt will be evident from the temperature rise resulting from the heating composition. Typically, suitable nonhalide copper salts are those that react with halide salts in water to produce copper halide. The following are expected to be suitable nonhalide copper salts: copper acetate Cu(C₂H₃O₂)₂, copper formate Cu(CHO₂)₂ and copper lactate Cu(C₃H₅O₃ )₂. One copper salt that cannot be included in systems of this invention as a nonhalide copper salt reactant in heaters that include either copper halide or catalyst is copper nitrate Cu(NO₃)₂. This and other nitrate salts have been found to be poisons of halide salt catalysts. They can be used to stop the reaction according to the methods described in international patent application WO 2005/108878 A2. Such nitrate compounds can be included in heaters of this invention if normally sequestered but releasable into the catalyst-containing reaction to suppress or terminate the heat-generating reaction, if the temperature rises to a predetermined maximum level.

User-activated, single-use chemical heaters according to this invention include the above- described heating systems. Such heaters include at least one compartment of a first type containing a portion of the heating-system reactants and at least one compartment of a second type containing the remaining heating-system reactants, plus a separator therebetween, such as, for example, a valve or frangible seal or rupturable inner compartment holding liquid reactants, that a user can operate or cause to operate so as to compromise the separation of the two compartment types, otherwise sealed from one another, and allow their contents to mix, thereby initiating the heat-generating reaction. Depending on the use intended, the heater may also include a separate compartment for a product to be heated, for example, a beverage or military meal. System reactants are divided between the first and second types of compartments to prevent initiation of the heating reaction prior to compromise of the separation means. Heaters according to this invention may also include a reaction suppressor or killer either in a compartment that can be automatically compromised to release its contents into the reaction or otherwise sequestered in a releasable form, for example, a wax applied to the product compartment.

If the reactants are aluminum metal and copper halide, the aluminum and copper halide can be stored as dry reaction ingredients in one compartment, and water can be stored in another compartment. Alternately and preferably, the copper halide can be dissolved in, and stored with, the water. It is less preferred to split the water between the two types of compartments, that is, to store aluminum plus a portion of the water in one compartment and to store the copper halide dissolved in the remaining portion of the water in another compartment.

If the reactants are aluminum metal, copper sulfate, and copper halide, we prefer to store the metal and the sulfate as dry ingredients in one compartment and the copper halide dissolved in the water in another compartment. A portion of the water could be included with the metal and sulfate, because the metal and sulfate do not react in the presence of water, but we prefer to place all the water in the other compartment type. Less preferred is to store the three active ingredients (aluminum, copper sulfate and copper halide) in one compartment and all of the water in a second compartment. That approach is less preferred, because it presents more chance of premature initiation, should moisture enter the compartment holding the dry materials.

Similarly, if the reactants are aluminum metal, copper sulfate, and halide salt catalyst, we prefer to store the metal and sulfate in one compartment as dry ingredients and the halide salt catalyst dissolved in water in another compartment. Here again, a portion of the water could be included with the metal and sulfate, but we prefer to keep them as dry ingredients. Less preferred, for the reason stated above, would be to store the metal, sulfate and halide salt as dry ingredients in one compartment and the water in another compartment. If, in addition to halide salt catalyst, the system includes sodium acetate or another catalyst activator, we prefer to store the activator with the halide salt catalyst in the compartment also containing the water. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

Brief Description of the Figures

FIG. 1 is a chart showing temperature as a function of time for the heating composition described in Example 1.

FIG. 2 is a chart showing temperature as a function of time for the heating composition described in Example 2.

FIG. 3 is a chart showing temperature as a function of time for the heating composition described in Example 3.

FIG. 4 is a chart showing temperature as a function of time for the heating composition described in Example 4.

FIG. 5 is a chart showing temperature as a function of time for the heating composition described in Example 5.

FIG. 6 is a chart showing temperature as a function of time for the heating composition described in Example 6.

FIG. 7 is a chart showing temperature as a function of time for the heating composition described in Example 7.

FIG. 8 is a chart showing temperature as a function of time for the heating composition described in Example 8.

FIG. 9 is a chart showing temperature as a function of time for the heating composition described in Example 9.

FIG. 10 is a chart showing temperature as a function of time for the heating composition described in Example 10.

FIG. 11 is a chart showing temperature as a function of time for the heating composition described in Example 11.

FIG. 12 is a chart showing temperature as a function of time for the heating composition described in Example 12.

FIG. 13 is a chart showing temperature as a function of time for the heating composition described in Example 13. FIG. 14 is a chart showing temperature as a function of time for the heating composition described in Example 14.

FIG. 15 is a chart showing temperature as a function of time for the heating composition described in Example 15.

FIG. 16 is a chart showing temperature as a function of time for the heating composition described in Example 16.

FIG. 17 is a simplified, block diagrammatic view of a heater according to this invention.

Like reference symbols in the various drawings indicate like elements.

Detailed Description of Preferred Embodiments

An embodiment of a user-activatable, single-use chemical heater according to this invention is shown in FIG. 17. Heater 1 includes compartment 2, a reactant compartment of a first type (only one shown for ease of understanding) and compartment 3, a reactant compartment of a second type (only one shown for ease of understanding). Compartments 2, 3 are generally sealed from one another but their separation includes a user-operable separator, here shown as valve 4. To activate the heat-generating reaction, a user operates the separator, here by opening valve 4, which allows mixing of the contents of compartments 2, 3 and the initiation of the heat-generating reaction in one or both compartment types. In FIG. 17 compartment 2 is shown disposed within compartment 3, but it will be appreciated that it may be outside compartment 3 and separated therefrom by, for example, a frangible seal. When compartment 2 is disposed within compartment 3, as shown, we prefer that water be included in compartment 2 so that the contents of compartment 2 flow into compartment 3, which contains dry reactants. Compartment 3 thereupon becomes the reaction compartment.

Heater 1 also includes compartment 5, a compartment for a material to be heated. Compartment 5 as shown is disposed largely within compartment 3, such that steam generated in compartment 3 can condense on much of the surface of the wall separating compartment 5 from compartment 3. It will be appreciated that compartment 5 can be thermally connected to compartment 3 otherwise, for example, by being disposed adjacent thereto, separated by a heat- conducting wall, hi embodiments that do not include and are not intended to accommodate a product to be heated, such as a heat pack, compartment 5 will not be included. Heater 1 further includes a sequestered but releasable reaction suppressor or terminator, such as a nitrate catalyst poison, here shown as was ring 6 applied to the outer surface of compartment 5 but releasable into compartment 3 upon melting of the wax when a predetermined temperature is reached at the wall separating compartment 5 from compartment 3. Wax ring 6 contains a suppressor or reaction-killing composition. It will be appreciated that a reaction suppressor or killer could be included in a closed compartment having a release mechanism that activates automatically when a predetermined temperature is reached. It will also be appreciated that a reaction suppressor or killer will not be included in all embodiments.

Methods according to this invention comprise the use of a heater according to this invention. A user compromises the separation of reactant compartments of the first and second type, thereby initiating the heat-generating chemical reaction. Methods according to this invention may also include supplying the heater, supplying the product or object to be heated, or both.

Heating compositions of this invention utilize the oxidation-reduction reaction in water of aluminum metal (Al) with a copper halide salt, preferably copper chloride (CuCl₂). Aluminum is used in a form that provides a high surface area relative to a block of aluminum. We have utilized three such forms: aluminum flakes, aluminum strips, and aluminum wool. The aluminum flakes were aluminum foil 0.05 mm thick chopped into flakes 1 mm square. The aluminum strips were aluminum foil 0.025 mm thick cut into strips about 6 mm wide and about 170 mm long. The aluminum wool was made from aluminum wire 0.04 mm in diameter. Substitution of Al wool for Al flakes increased the surface area available for reaction and also increased the openness of the Al structure for better circulation of the water and soluble reactants, which promotes completeness of the heat-generating reaction. The surface area of the flakes was 40 mmW. The surface area of the wool was 100 mmW. Comparison of Examples 7 and 8 shows that substitution of Al wool (Ex. 8) for Al flakes (Ex 7) increased both the rate and completeness of the reaction. The thinner 0.025 mm aluminum strips (80 mmW) were only used in Example 16. The strips did not pack as tightly as the flakes, and therefore performed more like the wool.

Heat-generating reactions of systems according to this invention can be illustrated by a series of equations. In the description that follows, copper halide is represented by copper chloride, nonhalide copper salt is represented by copper sulfate, and halide salt catalyst is represented by sodium chloride. Water of hydration is omitted from the equations for the sake of clarity. Persons skilled in the art will understand how to write the equations utilizing alternative ingredients.

In addition to Al metal, the oxidation-reduction reactions of this invention utilize a water- soluble copper halide, preferably copper chloride. Copper halide may be included as a starting ingredient, for example in the form of copper chloride hydrate (CuCl₂-2H₂O). The reaction is represented by Reaction 1, which is exothermic (water of hydration is omitted from reactions reported below for the sake of clarity, as indicated above):

3 CuCl₂ + 2 Al = 3 Cu + 2 AlCl₃ (Reaction 1) Reaction 2 may also occur to clear any oxide layer off the surface of the aluminum:

3 CuCl₂ + Al₂O₃ = 3 CuO + 2 AlCl₃ (Reaction 2)

The copper halide can be the sole source of copper for the reaction. Alternatively, one may utilize a mixture of the copper halide with a nonhalide copper salt that itself does not react with aluminum metal in water but that does react to generate copper halide in the presence of aluminum metal, copper halide and water. Such a mixture is believed to utilize Reaction 1 , in combination with Reaction 3:

3 CuSO₄ + 2 AlCl₃ = 3 CuCl₂ + A1₂(SO₄)₃ (Reaction 3)

Alternatively, when a suitable (not copper nitrate) nonhalide copper salt is used with a catalyst, copper halide can be generated in the reaction by its reaction in water with a soluble halide salt catalyst, preferably an alkali or alkaline earth metal halide, by means of Reaction 4:

2 NaCl + CuSO₄ = Na₂SO₄ + CuCl₂ (Reaction 4)

We refer to the halide salt catalyst as a catalyst because it is not consumed in the heat- generating reaction between copper and aluminum, but rather it reacts with the nonhalide copper salt to create a copper halide and is then regenerated.

Combining Reaction 1 with Reaction 3 gives Reaction 5:

3 CuCl₂ + 2 Al = 3 Cu + 2 AlCl₃ (Reaction 1 ) 3 CuSO₄ + 2 AlCIj = 3 CuCl? + Al₇(SOA (Reaction 3) 3 CuSO₄ + 2 Al = 3 Cu + A1₂(SO₄)₃ (Reaction 5)

Further, we have discovered that addition of sodium acetate, for example as sodium acetate trihydrate (NaC₂H₃O₂-3H₂O) to heating systems utilizing soluble halide salt such as NaCl increases both the initial heating rate of the reaction and the total amount of heat generated. We refer to this ingredient as a catalyst activator.

Examples

Example 1

A mixture of 13.0 g CuCl₂-2H₂O and 1.34 g aluminum flakes were placed into 200 ml of water in an insulated flask. The temperature, as shown in FIG. 1, heated from 24.7°C to 54.3⁰C. The initial rate of heating was about 23°C/minute. This example shows that copper chloride has a rapid exothermic reaction with aluminum metal.

Example 2

A mixture of 20.0 g CuSO₄ SH₂O and 1.43 g aluminum flakes were placed into 200 ml of water in an insulated flask. The temperature, as shown in FIG. 2, cooled from 24.2°C to 23.3°C. The endothermic heat of solution for the salt exceeded any heat generated from the oxidation- reduction reaction. Essentially, there was no oxidation-reduction reaction. This example shows that copper sulfate does not react in water with high-surface area aluminum, unlike copper chloride.

Example 3

A mixture of 17.11 g CuSO₄ SH₂O and 1.30 g CuCl₂-2H₂O and 1.34 g aluminum flakes were placed into 200 ml of water in an insulated flask. The temperature, as shown in FIG. 3, heated from 23.4⁰C to 51.9°C. The initial rate of heating was about 1 l°C/minute. This example shows that a combination of copper halide and copper sulfate can be used to generate copper halide in the reaction, and that the copper halide in the combination can be a minor amount relative to the copper sulfate, in this case representing 10 wt. percent of the copper sulfate, and still generate as much heat as if all the Cu salt were CuCl₂. Substitution of copper nitrate, Cu(NO₃)₂, for copper sulfate in a heating composition of this type failed to generate heat.

Example 4

A mixture of 64.42 g CuSO₄-5H₂O and 5.57 g aluminum flakes were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water was added into the reaction chamber under the steel cup. The temperature of the water in the steel cup remained unchanged at 17⁰C for 8 minutes, showing the nonreactivity of the CuSO₄-5H₂O and aluminum flakes. At this point 10 ml water with 0.45g of CuCl₂-2H₂O dissolved in it was added to the reaction mixture. As shown in FIG. 4, the water in the steel cup heated from 17⁰C to 58⁰C in 4.2 minutes, and continued to heat to 67⁰C in 7.0 minutes. At this point the temperature recording stopped, but the reaction continued for some time beyond the 7.0 minutes. This example shows that copper chloride in the mixture with copper sulfate can be reduced to one percent. Together, Examples 3 and 4 show that the rate of reaction of copper sulfate-halide mixtures can be controlled by adjusting the relative amount of the copper halide.

Example 5

A mixture of 57.35 g CuSO₄-5H₂O and 0.27 g NaCl and 5.43 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup as an object to be heated. 50 ml water was added into the reaction chamber under the steel cup to activate the reaction. As shown in FIG. 5, the temperature of the water in the steel cup heated from 2O⁰C to 75⁰C. This example shows that in the copper sulfate- halide mixture of Examples 3 and 4 the copper halide can be replaced with a soluble halide salt such a common table salt, which reacts with the copper sulfate to generate copper halide (in this case copper chloride) in the reaction.

Example 6

A mixture of 57.35 g CuSO₄-5H₂O and 5.43 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup as a liquid to be heated. 50 ml water containing 0.14 g NaCl were added into the reaction chamber under the steel cup to activate the reaction. As shown in FIG. 6, the temperature of the water in the steel cup heated from 21⁰C to 78°C. This example shows that the system can include one compartment of dry ingredients (here aluminum and copper sulfate) and one compartment containing water and water-soluble salt, either sodium chloride (as shown) or copper halide (not shown).

Example 7

A mixture of 52.58 g CuSO₄ SH₂O and 3.99 g CuCl₂-2H₂O and 4.21 g aluminum flakes were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water was added into the reaction chamber under the steel cup. As shown in FIG. 7, the temperature of the water in the steel cup heated from 15°C to 49°C. After the heating stopped, the reactants were stirred, and the reaction started again, releasing steam. This example illustrates the use of aluminum flakes and provides a base for comparing the use of aluminum wool in Example 8.

Example 8

A mixture of 52.58 g CuSO₄-5H₂O and 3.99 g CuCl₂-2H₂O and 4.21 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water was added into the reaction chamber under the steel cup. As shown in FIG. 8, the temperature of the water in the steel cup heated from 20⁰C to 64°C. After the heating stopped, the reactants were stirred, and the reaction did not start again. Comparing Example 7 with this example, one sees that use of aluminum wool in place of aluminum flakes increased the temperature rise of the water in the steel cup from 34 ⁰C to 44 ⁰C and resulted in a complete reaction that did not restart upon subsequent stirring. Aluminum wool thus has advantages over aluminum flakes. In addition to promoting a complete reaction without stirring or other mixing, the heater can readily be designed such that if the heater is turned upside down, dumping a liquid being heated, the aqueous reaction liquid will drain away from the solid aluminum, stopping the reaction and preventing the temperature from rising excessively due to loss of the heat sink provided by the product being heated.

Example 9

A mixture of 54.00 g CuSO₄-SH₂O and 5.55 g aluminum flakes were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 60 ml water containing 0.26 g KBr was added into the reaction chamber under the steel cup. As shown in FIG. 9, the water in the steel cup heated from 22°C to 57°C in 14.2 minutes. This example shows that chloride is not the only halide ion effective for this invention.

Example 10

A mixture of 54.00 g CuSO₄-5H₂O and 5.45 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water containing 0.13 g NaCl were added into the reaction chamber under the steel cup. As shown in FIG. 10, the temperature of the water in the steel cup heated from 2O⁰C to 58⁰C in 4.1 minutes. The temperature of the water in the steel cup heated from 20⁰C to 72⁰C overall. This example illustrates the use of sodium chloride and provides a base case to compare to the further addition of sodium acetate in Example 11.

Example 11

A mixture of 54.00 g CuSO₄-5H₂O and 5.46 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water containing 0.13 g NaCl and 0.27 g NaC₂H₃O₂-SH₂O were added into the reaction chamber under the steel cup. As shown in FIG. 11, the temperature of the water in the steel cup heated from 20⁰C to 58°C in 3.1 minutes. The temperature of the water in the steel cup heated from 20⁰C to 74°C overall. This example illustrates the use of a catalyst activator. Comparison of Example 10 with this example shows that addition of a catalyst activator, here sodium acetate, increased the initial reaction rate to 12 °C/min from 9 ⁰C /min, and increased the amount of heat transferred to the inner cup to 265 cal/g of CuSO₄-5H₂O from 255 cal/g.

Example 12

A mixture of 55.00 g CuSO₄-5H₂O and 5.55 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water containing 0.30 g NaC₂H₃O₂-3H₂O were added into the reaction chamber under the steel cup. As shown in FIG. 12, temperature of the water in the steel cup started at 19.5°C and after 15 minutes it was still at 19.5°C. There was no reaction. This example shows that sodium acetate does not itself act as a catalyst.

Example 13

A mixture of 53.00 g CuSO₄-5H₂O and 5.35 g aluminum wool were placed into a 500 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 265 ml water was placed in the steel cup. 50 ml water containing 0.12 g CaCl₂ were added into the reaction chamber under the steel cup. As shown in FIG. 13, the temperature of the water in the steel cup heated from 20⁰C to 58⁰C in 2.8 minutes. The temperature of the water in the steel cup heated from 2O⁰C to 73⁰C overall. This shows that CaCl₂ can be used as a catalyst.

Example 14

A mixture of 17.11 g CuSO₄-5H₂O and 1.30 g CuCl₂-2H₂O and 1.34 g aluminum flakes were placed into 200 ml of water in an insulated flask. As shown in FIG. 14, the temperature heated from 22⁰C to 35°C, and then 8.00 g Cu(NO₃)₂-2.5H₂O were added. The dip in the temperature profile in FIG. 14 shows where the thermocouple was removed from the mixture to make room to add the Cu(NO₃)₂-2.5H₂O. The mixture heated to a maximum temperature of 37°C. The starting mixture is the same as in Example 3, but the total temperature rise was only 15°C, compared to 28.5°C in Example 3. The Cu(NO₃)₂-2.5H₂O stopped the reaction in the 4-5 seconds that it took to add the powder and mix it into the reaction mixture.

Example 15

A mixture of 56.00 g CuSO₄-SH₂O and 5.60 g aluminum wool were placed into a 510 ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 210 ml in the annular space between the two cups. A mixture comprising 9 g Mg(NO₃)₂-6H₂O and 13 g paraffin wax was applied to the outside of the steel cup. 265 ml water was placed in the steel cup. 60 ml water containing 0.15 g NaCl and 0.35 g NaC₂H₃O₂-SH₂O were added into the reaction chamber under the steel cup. As shown in FIG. 15, the temperature of the water in the steel cup heated from 21⁰C to 55°C in 2.6 minutes. The temperature of the water in the steel cup heated from 21⁰C to 57°C overall. From the change in slope of the heating curve in Figure 15 it can be surmised that the wax ring melted and fell into the reaction mixture, and the Mg(NOs)₂ caused the reaction to stop when the water reached 55°C.

Example 16

A mixture of 30.00g CuSO₄-5H₂0, 12.0Og KMnO₄, and 4.0Og shredded aluminum foil was placed into a 500ml plastic cup. A 300 ml steel cup was nested into the plastic cup, forming a reaction chamber of about 200 ml in the annular space between the two cups. 275 ml water was placed in the steel cup. 60 ml aqueous solution containing 4.5ml glycerol, 0.2Og HCl, and 0.06ml Surfynol SE-F surfactant from Air Products were added into the reaction chamber under the steel cup. As shown in FIG. 16, the temperature of the water in the steel cup heated from 20⁰C to 58⁰C in 2.8 minutes. The temperature of the water in the steel cup heated from 20⁰C to 72°C overall. This example illustrates: (1) the use of shredded aluminum foil; (2) the use of hydrogen chloride (HCl) as the non-copper water-soluble halide salt; (3) the use of a surfactant in the reactant; and (4) the addition of KMnO₄ and glycerol to the reaction mixture to reduce the overall amount of solid chemicals, compared to Examples 10, 11, and 13, which required about 25% more solids to produce similar heating results. It is believed that the surfactant helped the solution wet the aluminum.

Example 17

A mixture of 53.0Og CuSO₄ SH₂O, and 5.3Og shredded aluminum foil was placed into a 1000ml graduated cylinder. A 55 ml aqueous solution containing 0.18g HCl was added into the graduated cylinder. The reaction mixture produced steam, and foam rose up to 350 ml in the cylinder. The reaction was repeated with 0.01 ml/ml Dow-Corning FG-IO antifoam emulsion added to the solution. The maximum volume of foam was 310 ml. The reaction was repeated with 0.01 ml/ml Air Products Surfynol 504 surfactant. The maximum volume of foam was 250 ml. The reaction was repeated with 0.005 ml/ml Air Products SE-F surfactant. The maximum volume of foam was 220 ml. These reactions show that the volume of foam can be reduced either by an antifoam agent or a surfactant. Moreover, the surfactant was more effective in reducing the volume of foam than the antifoam agent.

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the heater could include a variety of possible physical configurations. Additionally, the specific amounts of each ingredient in a heater can differ depending on the specific heating requirements of each application. Moreover, materials used to manufacture a heater can vary depending on the requirements of a specific application. Accordingly, other embodiments are within the scope of the following claims.

Claims

What is claimed is:

1. A user-activatable, single-use chemical heater that includes at least one compartment of a first type separated from at least one compartment of a second type by a separator that is compromisable by a user to establish communication therebetween, wherein water and ingredients of a heating system that generates heat by the oxidation-reduction reaction between aluminum metal and a water-soluble copper halide are stored in and divided between said compartments of the first and second types so as not to initiate said heat-generating reaction until the contents of said compartments of the first and second types mix following compromise of said separator.

2. The heater of claim 1 wherein the ingredients of the heating system are aluminum metal and said copper halide.

3. The heater of claim 2 wherein the aluminum metal is stored in said at least one compartment of the first type and water and said copper halide are stored in said at least one compartment of the second type.

4. The heater of claim 1 wherein the ingredients of the heating system are aluminum metal, a nonhalide copper salt and said copper halide.

5. The heater of claim 4 wherein the nonhalide copper salt is copper sulfate.

6. The heater of claim 5 wherein the weight of copper halide is less than one-half the weight of copper sulfate.

7. The heater of claim 5 wherein the weight of copper halide is less than fifteen percent of the weight of copper sulfate.

8. The heater of any of claims 4-7 wherein the aluminum metal and the nonhalide copper salt are stored in said at least one compartment of the first type, and wherein water and the remaining ingredients of the heating system are stored in said at least one compartment of the second type.

9. The heater of claim 1 wherein the ingredients of the heating system include aluminum metal, a nonhalide water-soluble copper salt and a catalyst.

10. The heater of claim 9 wherein the catalyst comprises at least one non-copper water-soluble halide salt or hydrogen halide.

11. The heater of claim 9 wherein the nonhalide water-soluble copper salt and the catalyst react with one another in water to produce copper halide.

12. The heater of claim 9 wherein the nonhalide water-soluble copper salt is copper sulfate.

13. The heater of claim 9 wherein the catalyst is selected from the group consisting of calcium chloride, magnesium chloride, sodium chloride, potassium chloride, calcium bromide, magnesium bromide, sodium bromide, potassium bromide, hydrogen chloride, hydrogen bromide and mixtures thereof.

14. The heater of any of claims 9-13 further including a nitrate salt that is automatically releasable.

15. The heater of any of claims 9-13 wherein the aluminum metal and the nonhalide copper salt are stored in said at least one compartment of the first type and water and the remaining ingredients of the heating system are stored in said at least one compartment of the second type.

16. The heater of any of claims 9-13 further including a catalyst activator comprising at least one water-soluble acetate salt.

17. The heater of claim 16 wherein the catalyst activator is sodium acetate.

18. The heater of claim 16 wherein the aluminum metal and the nonhalide copper salt are stored in said at least one compartment of the first type, and wherein water and the remaining ingredients of the heating system are stored in said at least one compartment of the second type.

19. The heater of any of claims 1 -7 wherein the aluminum metal is in a form that presents a large surface area.

20. The heater of any of claims 1 -7 wherein the aluminum metal is in a form selected from the following: aluminum wool, aluminum flakes and shredded aluminum.

21. The heater of any of claims 1 -7 wherein the non-copper water-soluble halide salt is hydrogen chloride.

22. The heater of any of claims 1-7 further comprising a surfactant.

23. The heater of any of claims 1 -7 further comprising potassium permanganate and glycerol stored in and divided between said compartments of the first and second types so as not to initiate said heat-generating reaction until the contents of said compartments of the first and second types mix following compromise of said separator.

24. The heater of any of claims 1 -7 further including a product compartment.

25. A method of heating comprising the steps of providing a heater according to claim 1 and compromising the separator between said at least one compartment of the first type and said at least one compartment of the second type.