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INVENTION
Russian Federation Patent RU2261537

PTC heater for enclosures

PTC heater for enclosures

Name of the inventor: Smyslov Igor
The name of the patentee: Smyslov Igor
Address for correspondence:. 123317, Moscow, Strelbischensky lane 5, kv.239, II Smyslov
Starting date of the patent: 2000.02.14

The invention relates to electric heating devices based on the heating resistors, and can be used as components for various heating devices to enhance their performance by more rapid heating and for energy saving and placing in a heating device due to its small size. Introduction 2 PTC heater in the body thus avoiding the need to isolate the PTC resistors from the body, thereby reducing the thermal resistance between the PTC thermistors and the housing.

DESCRIPTION OF THE INVENTION

The present invention relates to electricity, electric heating, resistive heating, structural heating elements, paired with connector parts, namely, to the body PTC heaters.

Widely known as a heater wire heating element comprising a metallic tubular body 1, a wire heating resistor 10 and the insulating filling 15/1 /.

Disadvantages 1st analog

1. Slow heating, for

1.1. Metals have a small positive TCR, so resistor must be greater than the nominal resistance that upon reaching a predetermined temperature, eg 300 ° C, all of which arose the heat dissipated, so small initial current slowly heats the resistor, moreover, it immediately begins to decrease.

1.2. The insulating filling has large thermal resistance.

2. The overrun of electricity due to slow warming.

3. Fire hazard, for possible interturn circuit and the housing.

Known posistor carburetor heater comprising a heat line of the plate 1, at the end of which a good thermal and electrical contact mounted posistor 3/2 /. PTC thermistor - a resistor in the form of a body of simple shape of the semiconductor ceramic with electrodes having an abnormally large positive TCR in a very narrow temperature range (field reversible phase transformation in substance PTC), where the resistance is growing at about 3 ... 4, so when the flows high current, rapid heating posistor, but the resistance is even slightly reduced, but at the phase transition resistance increases sharply, the current drops sharply to a value which provides a refund of heat dissipation, so posistor can not overheat, ie, posistor temperature capable of self-sustaining, as it feeds the automatic temperature maintenance system. Therefore, PTC thermistor heater does not have a heating element deficiencies or are substantially reduced.

Disadvantages of 2nd analog

1. Insufficient rapid heating, because the heat is dissipated from the outer verge of winding protection and surface heat flux heat line is going to the other end.

2. The overrun of electricity due to the heat loss dissipated is the carburetor.

As a prototype selected PTC thermistor heater corps, comprising a housing having a circuit comprising a posistor, internal input and the case itself, which serves external input, paired with PTC thermistor with a small electrical and thermal resistance / 3 /. In the prior art (Figure 5) metal housing 7 is U-shaped with wide walls of electric circuit is clamped in a stack (bottom-up): insulator 4, inner gland 2, one electrode (not shown) thermistor body 1, the other electrode ( not shown) thermistor 1. Some items are named correctly than in the description of the prototype. Posistors - thin, but wide for greater heat transfer electrodes 2 (2) - on the broad faces PTC body, they do not reach the edges of the thermistor to form a security zone 3, prevents the electrode circuit if accidentally touched with the housing 7. The end of the internal input 2 ( 5) is not beyond the electrode boundary. Prototype function as intended.

Disadvantages of the prototype

1. The need for an internal insulator 4 input 2.

2. Not more rapid heating of the body 7 of the insulator 4.

3. Overspending electricity due to not the most rapid heating and heat dissipation through 3 open side of the housing 7.

The technical result of the invention is to eliminate these disadvantages: the removal of the insulator from entering the inner body may rapid heating and electricity eliminating overruns.

This technical result is achieved by the fact that the PTC heater body comprising a housing having a circuit including posistor, internal input and the body itself, which serves external input, coupled with the PTC thermistor with a small electrical and thermal resistance, according to the present invention, the housing is made of elektroteploprovodnogo material hollow with the smallest wall thickness, sufficient only to prevent damage to the electrical circuit, electric circuit is equipped with a 2nd PTC symmetrical 1st, relative to the vertical plane of symmetry of the body, the internal input and made a spring mounted between vraspor PTC thermistors.

PTC heater for enclosures

The drawing shows the heater corps paropozistorny side view. If the name items have numbers, then it is clear from the description and prior art, it can not be on the drawing. In the metallic or conductive polymeric housing 1 in the form of a flat parallelepiped with a cavity open on one side, with the walls of the smallest thickness sufficient only to prevent damage accommodating the electric circuit comprising a pair of planar PTC 2n (left) and 2n (right) arranged symmetrically vertical plane of symmetry of the housing 1, inner spring gland 3 and the housing 1 itself serving as an external input; Input 3 is set vraspor between PTC thermistors 2, so presses their broad faces to the housing 1. On both broad faces of each PTC thermistor 2 standard electrodes are made in the form of thin metal coating, so 1 are connected in parallel between the input 3 and the housing 1, serving as an insulator to prevent short circuit between them and the current supply conductors, which is the basic conception of the heater and the cause of its advantages. Entrance to the cavity of the body 4 closed insulating cap secured to the housing 1 projecting oppositely bent edges 5 broad walls of the housing 1; along Tube 4 missed the beginning of the input. Narrow wall of the housing 1 is provided with longitudinal bends (and bottom) to reduce thermal stresses. To supply to a heater body 1 and input 3 may be connected using means known clamps, soldering, etc. Heater can be tightly inserted into the heating device; 6 ... at a voltage of 36 V, DC or AC, the power may be heated using a single-wire device as one of the wires; at higher voltage between the body 1 and slot it into the heating device must be firmly inserted heat-conductive insulating gasket. Air heating or heating fluid can be secured to the power supply means, such as a cable strands attached to the body 1 and input 3.

Heater works are known in the art. This heater has a greater heat flow through the parallel connection of PTC 2n and 2n (the proof: as connected to the e / lamp), the lowest thermal resistance between the PTC thermistors 2 and the housing 1, the passage of almost all of the heat flow through the body 1 and its low heat capacity. For these reasons, it has almost no expenditure of power. Lack elektroizoyaltsii between PTC thermistors 2 and the housing 1 is not harmful, since the contact resistance between them is large outside the electrodes, and an accidental low resistance of the volume of PTC between spot interface and the introduction of 3 acts as a further connected in parallel posistor, accelerating the warming, but overheated it can not, for PTC resistors 2 is prevented.

Benefits posistor heater with a metal resistor

1. Improved performance and power savings for these reasons and the passage of all the heat flow from the middle of the heater.

2. Fire and technological safety, for preventing excessive heating of the heated material and the environment.

3. The ability to supply different kinds of stress in a wide range of nominal values ​​without any further action: the absence of the insulation body 1 from the heater - from 6 to 36, with insulation, ensuring security - from 120 and above.

4. Use of heaters in small sizes.

5. No expensive devices designed to maintain temperature, and more precise temperature control, because there is no relay and control circuits and actuators, which delayed the passage informs and command signals and operations.

The advantage over the prior art

1. Maximum speed of the heating due to the use of 2 PTC, lower thermal resistance between the PTC thermistors and the case without an insulating plate between them, the absence of heat loss through a closed casing 1.

2. Energy savings thanks to the almost total absence of heat losses specified in claim 1 reasons.

INFORMATION SOURCES

1. J. Birney. S. Francis RJ. Tubular electric, DPS Application № WO 97/28670, ICI H 05 3/50.

2. Nikolaev Yu et al. PTC heater combustion engine carburetor, Russian patent 2020254, MKI F 02 M 31/12, 1992/93

3. Doctorovich ZI Thermoresistive element RF 2068587, MKI N No. 01 C 7/02, 1994/96, the

CLAIM

Posistor hulled heater comprising a metallic body serving as an outer electrical input, from a circuit posistor which its one electrode is associated with the housing wall with a small electrical and thermal resistance, and the other - with the internal electrical input, characterized in that the housing is made of electrically conductive material hollow with the smallest wall thickness, sufficient only to prevent damage to a circuit provided with a second electric circuit PTC, internal I made a spring and set vraspor between PTC thermistors.

print version
Publication date 26.03.2007gg