JPH09161948A - Ptc heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently heat a heated medium on a radiating plate by providing a projection on the radiating plate provided on an insulating plate covering the opening section of a box-like case in a PTC heater. SOLUTION: A plate-like spring 3 is arranged in a box-like case 2, an electrode plate 4a is arranged on the plate-like spring 3, and a PTC element 1 is arranged on the electrode plate 4a. An electrode plate 4b is arranged on the PTC element 1, an insulating plate 6 is arranged on the electrode plate 4b, a radiating plate 5 is arranged on the insulating plate 6, and the radiating plate 5 is caulked to the case 2. A projection is provided on the radiating plate 5 to be kept in contact with a heated medium to cover most of the case 2 including an opening section. The heated medium can be efficiently heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTC heater applied as a heat source to a heater for heating clothes dryers, electronic mosquito traps, humidifiers and the like.

[0002]

2. Description of the Related Art A conventional PTC heater will be described below with reference to the drawings.

FIG. 6 is a CD sectional view of the conventional PTC heater in FIG. 7, FIG. 7 is a perspective view of the conventional PTC heater, and FIG. 8 is a sectional view when heating a liquid by the conventional PTC heater. Is. 6, 11 is a plate-shaped positive temperature coefficient thermistor element (hereinafter referred to as PTC element), 12 is a box-shaped case (hereinafter referred to as case), 13 is a plate-shaped spring, and 14a, 1
4b is an electrode plate, 15 is a heat dissipation plate, and 16 is an insulating plate. In FIG. 8, 17 is a packing, 18 is a medium to be heated, 19 is a tank for storing a medium to be heated (hereinafter referred to as a tank), 2
0 is a fixing screw. Heat sink 1 of conventional PTC heater
Reference numeral 5 denotes a flat surface. When heating a liquid using this PTC heater, as shown in FIG. 8, the tank 19 having an opening at the bottom is attached to the case 12 using the fixing screw 20, and the liquid is discharged from the bottom. The tank 19 is provided with a groove so that the oil does not flow out, and the packing 17 is installed in the groove to heat the groove.

[0004]

However, since the radiator plate of the conventional heater is flat, a concave portion having the same height as the thickness of the bottom portion of the tank 19 is generated to suppress the natural body flow of the medium to be heated and to heat it. However, there is a problem in that the efficiency of is reduced.

An object of the present invention is to solve the above conventional problems and to provide a PTC heater having high heating efficiency.

[0006]

To achieve this object, a PTC heater according to the present invention comprises a case having an opening,
A plate-shaped PTC thermistor which is housed in this case and has at least a pair of electrodes on its surface;
At least a pair of terminals electrically connected to the thermistor and drawn out of the case, an insulating plate provided on the PTC thermistor, and an insulating plate provided on the insulating plate so as to cover the opening of the case. A heat sink, and the heat sink has a convex portion.

According to this structure, the heating surface of the PTC heater and the bottom surface of the tank can be made substantially flush with each other.
When the medium to be heated is a liquid, the natural body flow is not obstructed, and heating can be performed efficiently. In addition, compared to the conventional case, the distance between the joint surface between the case and the heat sink and the joint surface between the tank and the heat sink that is installed above the heat sink is longer, so the steam generated by heating enters the case inside. The possibility of intrusion can be reduced.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention includes a case having an opening, a plate-like PTC thermistor housed in the case and having at least a pair of comb-shaped electrodes on the surface thereof. At least a pair of terminals electrically connected to the PTC thermistor and drawn out of the case, an insulating plate provided on the upper part of the PTC thermistor, and an insulating plate provided on the upper part of the insulating plate so as to cover the opening of the case. The heat radiation plate is a PTC heater having a convex portion, and can heat the medium to be heated efficiently.

According to a second aspect of the invention, the case has a double structure, and the outer case is made of resin, porcelain or stainless steel,
The inner case is made of an insulative material in addition to being formed of any metal of aluminum, copper, and zinc, or an alloy thereof, and the double structure makes it difficult to exert an internal influence on the outside. If the outer case is made of metal, the thermal efficiency will be further improved.

According to the third aspect of the present invention, a heat sink whose surface is coated with a heat resistant resin is used, and the heat sink is less likely to corrode.

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a cross-sectional view taken along the line AB of the PTC heater of this embodiment in FIG. FIG. 2 is a perspective view of the PTC heater of this embodiment. FIG. 3 is a cross-sectional view of heating a liquid using the PTC heater of this embodiment. In FIG. 1, 1 is a plate-shaped PTC thermistor element (hereinafter referred to as PTC element), 2 is a case, 3 is a plate-shaped spring, 4a and 4b are electrode plates, 5 is a heat radiating plate, and 6 is an insulating plate. In FIG. 3, 7 is a packing, 8 is a medium to be heated, and 9 is a medium to be heated.
Is a tank, and 10 is a fixing screw. The PTC element 1 is
A semiconductor element containing barium titanate as a main component, on which electrodes of silver, aluminum, zinc, etc. were printed and baked. The shape was a square plate or a disk and had a thickness of 1.0 mm to 5.0 mm. It is a thing. Case 2 is made of an insulating material such as PPS.
It is formed by using a resin of equal quality or porcelain such as alumina or steatite. The plate-shaped spring 3 is made of a metal having a spring property, such as stainless steel or phosphor bronze, to fix the PTC element 1. Metals such as stainless steel and copper are used for the electrode plates 4a and 4b. The insulating plate 6 has good thermal conductivity and is an insulating porcelain,
For example, alumina or the like is used. This PTC heater is assembled by first disposing the plate-shaped spring 3 inside the case 2,
Next, the electrode plate 4a is arranged on the upper part of the plate-shaped spring 3, then the PTC element 1 is arranged on the upper part of the electrode plate 4a, and then the PTC element 1 is arranged.
The electrode plate 4b is arranged on the upper part of the element 1, the insulating plate 6 is arranged on the upper part of the electrode plate 4b, then the heat sink 5 is arranged on the upper part of the insulating plate 6, and then the heat sink 5 is caulked to the case 2. It is a thing. As for the method of use, the packing 7 is arranged in the groove of the tank 9, the PTC heater is arranged in front of the packing 7 so that the heat radiating plate 5 is located, and fixed by screwing or the like. And the electrode plate 4
A voltage is applied to a and 4b to heat the heated medium 8 in the tank 9. The tank 9 may be fixed not only by screwing but also by fixing with a band, bonding or the like.

Further, between the heat dissipation plate 5 and the insulating plate 6, the PTC
A structure in which a resin (not shown) having good thermal conductivity such as heat dissipation grease is applied between the element 1 and the insulating plate 6 may be used. Alternatively, the plate spring 3 may be a coil spring (not shown). Further, the installation direction of the PTC heater in the usage method may be a vertical direction (not shown).

(Second Embodiment) FIG. 4 is a sectional view of a PTC heater according to the present embodiment. In FIG. 4, 1 is PT
C element, 2 is a case, 4b is an electrode plate, 5 is a heat dissipation plate, and 6 is an insulating plate, which are the same as those in the first embodiment. The difference from the first embodiment is that the plate spring 3 and the electrode plate 4a in FIG. 1 are integrated to form a plate spring terminal 3a, and the number of components is reduced. The plate-shaped spring terminal 3a is made of a metal having a spring property such as stainless steel or phosphor bronze. The assembling method and the using method are the same as those of the first embodiment except that the plate-shaped spring terminals 3a are arranged at the positions where the plate-shaped spring 3 and the electrode plate 4a are arranged.

As in the first embodiment, a resin (not shown) having good heat conductivity such as heat radiating grease is provided between the heat radiating plate 5 and the insulating plate 6 and between the PTC element 1 and the insulating plate 6. The structure may be applied.

(Embodiment 3) FIG. 5 is a sectional view of a PTC heater according to the present embodiment. In FIG. 5, 1 is PT
C element, 3 is a plate spring, 4a and 4b are electrode plates, 5 is a heat radiating plate, and 6 is an insulating plate, and the above is the same as in the first embodiment. The difference from the first embodiment is that the case 2 is divided into an inner case 2a and an outer case 2b. The inner case 2a is made of flame-retardant resin such as PPS or porcelain such as alumina or steatite, and the outer case 2b is
A metal of stainless steel, aluminum, copper, zinc, or an alloy thereof is used. The assembling method and the using method are the same as those in the first embodiment except that the inner case 2a is arranged inside the outer case 2b.

As in the first embodiment, a resin (not shown) having good heat conductivity such as heat dissipation grease is provided between the heat dissipation plate 5 and the insulating plate 6 and between the PTC element 1 and the insulation plate 6. The structure may be applied.

In the first to third embodiments, the heat radiating plate 5 is made of any one of stainless steel, aluminum, and copper, which has a high thermal conductivity. The heat radiating plate 5 has a heat-resistant surface such as a fluororesin. Corrosion of the heat dissipation plate 5 can be prevented by coating with a resin having excellent properties and heat conductivity.

[0018]

As described above, the PTC heater according to the present invention has a heat radiating plate which has a convex portion in the central portion which comes into contact with the medium to be heated and which is covered so as to cover most of the case including the case opening. By using, the heat generation efficiency is high and there is almost no influence of generated steam.

[Brief description of the drawings]

FIG. 1 is a sectional view of a PTC heater according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a PTC heater according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a case where a liquid is heated using the PTC heater according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a PTC heater according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a PTC heater according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a conventional PTC heater.

FIG. 7 is a perspective view of a conventional PTC heater.

FIG. 8 is a sectional view showing a case where a liquid is heated using a conventional PTC heater.

[Explanation of symbols]

 1 PTC thermistor element 2 Case 4a Electrode plate 4b Electrode plate 5 Heat dissipation plate 6 Insulation plate

Claims (3)

[Claims] 1. A case having an opening, a plate-shaped PTC thermistor which is housed in the case and has at least a pair of electrodes on the surface thereof, and which is electrically connected to the PTC thermistor and pulled out of the case. At least a pair of terminals, an insulating plate provided above the PTC thermistor, and a heat radiating plate provided above the insulating plate so as to cover the opening of the case are provided, and the heat radiating plate has a convex portion. PTC heater. 2. The case has a double structure, and the outer case is made of resin, porcelain or stainless steel, aluminum, copper,
The PTC heater according to claim 1, wherein the PTC heater is formed of any metal of zinc or an alloy thereof, and the inner case is formed of an insulating material. 3. The PTC heater according to claim 1, wherein a heat dissipation plate whose surface is coated with a heat resistant resin is used.