JPH0461856A - Pocket heater using peltier element - Google Patents

Abstract

PURPOSE:To obtain a pocket heater which permits lighting, extinguishment and temperature adjustment, and has high thermal efficiency and secures the stable temperature by nipping a Peltier element between a heating plate and a heat absorbing plate, allowing the heat generation surface and heat absorbing surface to be opposed, and installing a thermoswitch at a part of the heating plate and connecting it with a secondary battery. CONSTITUTION:The proper heat transmission performance, shape, area, and thickness as portable pocket heater are provided, and a Peltier element PU is set between a heating plate 3 and a heat absorbing plate 4, allowing a heating surface 1 and a heat absorbing surface 2 to be opposed, and nipping-fixed, applying heat transmission grease and reducing thermal resistance. A thermoswitch 7 is insertion-arranged in a blind hole formed at a part of the heating plate 3, connected in series with the Peltier, element PU and connected with a secondary battery through a cord 8, and the temperature rise of the heating plate 3 is restricted to an upper limit temperature (about 65 deg.C). When the power switch S of the secondary battery B is closed, the Peltier element PU operates, and the temperature of the heating plate 3 is raised by the Joule's heat, and when the upper limit temperature is exceeded, the thermoswitch 7 is opened and the feed of electric power to the Peltier element PU is cut off, and the low temperature burn can be prevented.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention is directed to a portable hand warmer using a Peltier element.

(B) Conventional technology Traditionally, there have been portable pocket burners such as coal ash pocket burners, gasoline pocket burners, iron powder disposable pocket burners, and liquefied gas pocket burners. Even if it becomes unnecessary during the heating process, the only option is to leave it in the heating process until the end of the heating process, and of course it is impossible to ignite and extinguish it in small steps. However, there were drawbacks such as the fact that the temperature of the heat generated was difficult to stabilize because it was affected by the accuracy of the gas control valve and the outside temperature. In addition, battery-powered heating vests that use ordinary resistance heating elements are also known, but these use only Joule heat, which consumes a lot of power and consumes a lot of battery power. They had shortcomings, such as a large battery, which would increase the volume and weight, making it unsuitable for wear.

(c) Problems to be Solved by the Invention The present invention provides a portable pocket warmer that uses a Peltier element to freely control ignition, extinguishing, and temperature control, and that operates at a stable temperature with excellent heating efficiency. This is the problem that we are trying to solve, and this will eliminate the various drawbacks of all conventional pocket warmers.

(2) Means for Solving the Problems The attached drawings FIG. 1 is an explanatory diagram showing the structure and connections of a hand warmer main body according to an embodiment of the present invention, and FIG. 2 (broken line A) is a circuit diagram of the battery case and the inside thereof. Fig. 3 is a perspective explanatory view showing the configuration and wiring of the pocket warmer body to which a thermistor is added. Fig. 4 (
Similarly, the broken line A) is an explanatory diagram of the structure of the battery case and the internal circuit.

In Figure 1 and Figure 3, (Pυ) is a Peltier element, (1) is its heat generating surface, and (2) is its heat absorbing surface.

(3) is a heat-generating plate, and (4) is a heat-absorbing plate. In this example, aluminum with good thermal conductivity is used as the material, and the inner surface is finished smooth and is suitable for a portable pocket warmer. It has a shape, area and thickness. The Peltier element (Pl) has a heat generating surface (1) and a heat absorbing surface (2) corresponding to each other between the heat generating plate (3) and the heat absorbing plate (4) and applying thermal conductive grease to reduce thermal resistance. It is clamped and fixed, (5) is its positive terminal, (6) is its negative terminal. (7) is a thermo switch, and heat generating plate (3)
A cord (
8) to supply power and limit the upper limit of the temperature rise of the heat generating plate (3). In this example, the upper limit temperature is set at approximately 65°C, and if it exceeds this, the thermo switch (7) opens to cut off the power supply to the Peltier device (PLII). This prevents low temperature burns and also prevents damage to the Peltier device (pH) due to temperature rise.

(9) indicates a thermistor.

Figure 2 (dashed line A) shows the battery case, inside which there is a power switch (Sl) and a cord (8
A secondary battery (81) for supplying power through a Peltier element (Pug) and a bridge diode f connected to the plug (Pl via a reactance capacitor (C1)
A charging circuit that charges the secondary battery (8) connected to the DC output side of the secondary battery (8D) with an appropriate current, and a power supply O
The light emitting diode (ED) that displays N is built-in, and is used by being hung from a waist belt or the like. Also, plug (P
) can be folded and stored in a part of the battery case (dotted line A).

Figure 4 (10) is a temperature detection circuit, in which the resistance change due to temperature of the thermistor (9) is input through the connected cord (8), and is converted into a change in DC voltage corresponding to the temperature change. Output to amplifier (11). The amplifier (11) converts this voltage into a comparator (
12) to a voltage sufficient to operate the comparator (12), and the comparison voltage input terminal (V
co). On the other hand, a reference voltage input terminal of a comparator (12) to which an arbitrary set temperature, that is, a set reference voltage (hereinafter simply referred to as reference voltage) is connected from the sliding terminal of a variable resistor (VRI) that is connected to a power source and acts as a bleeder ( v re).The comparator (12
) is provided with a beam relay +RY), and when the comparator (12) is activated, the relay 1RY) is activated and its break contact (y) is opened to open the Peltier element
) is configured to cut off the power supply to the

The device of this embodiment is configured to be controlled using a beam relay (RV) and its break contact m, which is kept in the ON state when the comparator (12) is inactive, Although it is easy to control by replacing a semiconductor device configured to turn off when activated, the purpose of using a relay is that the power source is a portable secondary battery, so the volume, weight, etc. Considering this, a battery with a capacity that can be used for 5 to 6 hours per charge (UH = 1 x
(equivalent to 3), so if a semiconductor is used for control, the supply voltage will drop by around 0.6V, and the power consumption inside the semiconductor will lead to a reduction in drive time, so control by relay was prioritized. It is something.

(E) Function First, the function of the hand warmer according to the embodiment shown in the first and second figures will be described. Now, put the main body of the pocket warmer shown in Figure 1 into a bag made of flocked cloth, insert it between the clothes of the body part you want to warm, hang the battery case (broken line A) on your waist belt, etc., and close the power switch (fs). Then, power is supplied from the secondary battery (B), the light emitting diode (LED) lights up, and the power is turned on.
Display N.

At the same time, the secondary battery (B) positive side → the positive side of the cord (8) → Peltier element (PI) → thermoswitch (7) →
A closed circuit is formed with the negative side of the cord (8) → the negative side of the secondary battery (B), and the Peltier element (PUL) is activated and the heat generating plate (3) is heated by Joule heat and the temperature rises.At the same time, the heat absorbing plate ( 4) starts absorbing heat from the outside air and the heat transfers to the heat generating surface (1), so the heat absorbed is added to the heat generating plate (3) which is being heated by Joule heat, and heating progresses further. After several minutes have passed, when the temperature of the heating plate (3), which has risen due to heating, reaches around 65°C, the thermoswitch (1) opens and cuts off the power supply to the Peltier element (PI), so the element (PU) The heating operation is stopped and the temperature of the heating plate (3) gradually decreases, and when it reaches around 58℃ due to the hysteresis of the thermoswitch (7), the switch (7) is closed and power is supplied, and the Peltier element (Putl) is turned on again. starts to operate, the heating plate (3) is heated and its temperature rises, and this operation is repeated thereafter. Therefore, the heating plate (3) always maintains a temperature between 58℃ and 65℃ to warm the body parts. In addition, when the Peltier element (pH) is in operation, the heat absorption plate (4) always absorbs heat and its temperature decreases, so the heat absorption plate (4) can be used as a substitute for an ice pack, such as head cooling. However, in this case, the refrigeration efficiency relative to the power consumption is less than 20%, although it depends on the outside temperature and other conditions.

In addition, since the hand warmer of this example is used in a bag made of flocked cloth, the actual sensible temperature is around 57'C on average, so there is no risk of low-temperature burns even if the same part is heated for a long time. However, if you feel that the temperature is too high, open and close the power switch (31) to adjust the temperature. In this way, use it for a total of 5 to 6 hours until the secondary battery (8) has discharged. When finished, open the power switch (S), pull up the plug (Pl) that is folded and stored in a part of the battery case (dashed line A), and connect it to a commercial power source. A charging circuit consisting of bridge diodes (BDI)
The secondary battery (B) connected thereto can be charged with an appropriate direct current. According to the latest information, Sony
(corporate name) has announced a AA-type lithium-ion storage battery (product name), which has an energy capacity and energy density 2.9 times that of a nickel-cadmium secondary battery.
It should be noted that there is a secondary battery that has 1,200 charge/discharge cycles and an average operating voltage of 3.6 V, which is optimal as a power supply battery for the hand warmer of this embodiment.

In the above embodiment of the pocket warmer, the upper limit temperature of 65°C, which is always controlled by the thermoswitch (7), that is, the actual temperature felt across the bag, 57°C, is too hot under normal usage conditions, except in extremely cold cases. It's temperature. At this point, the operation of one embodiment of the hand warmer shown in the third and fourth figures will be described.

First, set an arbitrary reference voltage to control the upper limit temperature to 65°C or less using a variable resistor (Vlll) and input it to the reference voltage input terminal (Vrel) of the comparator (12). When the power switch (Sl is closed, Power is supplied to the Peltier element (pu) through the connected break contact (y) and thermoswitch (7), and the heating plate (3)
is heated and its temperature increases, the thermistor (9)
The resistance change corresponding to the temperature is input to the temperature detection circuit (10), converted to a DC voltage corresponding to the temperature, and output to the connected DC amplifier (11), which amplifies this voltage. The voltage is input to the comparison voltage input terminal (V cp) of the comparator (12) connected to the voltage. If this comparison voltage is lower than the set reference voltage, the comparator (
12) is not activated, and the temperature of the heating plate (3) is increased by supplying power to the Peltier element (PU) through the break contact of the relay or the semiconductor in the ON state, and when the comparison voltage exceeds the reference voltage, The comparator (12) operates and the break contact of the relay opens, or the semiconductor turns OFF, cutting off the power supply to the Peltier element, so the heating plate (
3) When the temperature gradually decreases below the set temperature, the comparator (12) will stop operating, so the relay will also stop operating and the break contact will close, or the semiconductor will recover and the O
In the N state, power is supplied to the Peltier element (PU), and the element (PI) operates to heat the heat generating plate (3) again. Thereafter, by repeating this operation, the heating plate (3) can warm the body parts while always maintaining the temperature between about 12 degrees Celsius and the set temperature. The other effects are the same as in the 81st case described above.

(f) Effects of the Invention The portable hand warmer using the Peltier element according to the present invention can freely control ignition, extinguishing, and temperature control, has extremely good heating efficiency, operates at a stable temperature, and is very convenient, compared to conventional hand warmers. This has great effects, as it eliminates all the drawbacks of hand warmers, and can also be used for cooling the head in place of an ice pack by using the heat absorbing plate on the opposite side.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration and wiring of a pocket warmer main body according to an embodiment of the present invention. Figure 2 (broken line A) is the battery case and internal circuit diagram. FIG. 3 is a perspective explanatory view showing the configuration and wiring of the hand warmer main body to which a thermistor is added. FIG. 4 (broken line A) is also an explanatory diagram of the structure of the battery case and internal circuit. In Figures 1 and 3, (pu) is a Peltier element, (3) is a heat generating plate, (4) is a heat absorbing plate, (7) is a thermoswitch, and (9) is a heat absorbing plate.
) is the thermistor, in Figure 2, (broken IIA) is the battery case, (B) is the secondary battery, (C1 is the reactance capacitor, (BO) is the bridge diode, in Figure 4, (10) is the temperature detection circuit, (11) is a DC amplifier, (12) is a comparator, (RY) is a relay, (
y) is a break contact, (V rel is a base 1s voltage input terminal, and (V cp) is a comparison voltage input terminal, respectively.

Claims (2)

[Claims] 1. The heat generating surface and the heat absorbing surface of the Peltier element are made to correspond to each other between a heat generating plate and a heat absorbing plate having appropriate thermal conductivity, area and thickness for a portable pocket warmer, and are clamped and fixed with low thermal resistance. A thermoswitch is provided, connected in series with the Peltier element, and a cord of an appropriate length is connected to it, and a battery case with a built-in secondary battery that is hung on the waist belt is installed, and the other end of the cord is connected to the power switch. The Peltier element is connected to a secondary battery through a cable and is equipped with a charging circuit powered by a commercial power supply, and can be freely ignited and extinguished, can control the upper limit temperature to prevent low-temperature burns, and can also be used for head cooling. A portable pocket warmer using 2. A thermistor is provided in a part of the heating plate to obtain a DC voltage, that is, a comparison voltage, in response to temperature changes of the heating plate, and when the comparison voltage is lower than a reference temperature, that is, reference voltage, arbitrarily set in advance with a variable resistor. for,
The comparator does not operate, but the temperature of the heating plate is increased by supplying power to the Peltier element through the break contact of the relay or the semiconductor in the ON state, and when the comparison voltage exceeds the set reference voltage, the comparator operates. Then, the break contact of the relay opens or the semiconductor turns OFF, cutting off the power supply to the Peltier element and reducing the temperature of the heat generating plate to below the set temperature. A portable hand warmer using the Peltier element according to claim 1, which can be set and used.