The higher the dry burning surface temperature of the PTC heating tube, the greater the stable power. However, increasing the surface temperature will increase the power attenuation, increase the breakdown chance of the PTC heater, and decrease the performance of the adhesive, wire, and insulation layer, and decrease the reliability.
When the dry burning surface temperature of the PTC heating tube is the same as the liquid temperature, the heating power is basically 0, that is, it is no longer heated. Therefore, the dry burning surface temperature of the PTC heating tube is always higher than the liquid temperature by more than 20°C, otherwise it cannot be heated. The smaller the difference between the dry surface temperature of the PTC heating tube and the liquid temperature, the smaller the power density of the heating tube, the larger the volume and the higher the cost.
PTC heater is also called PTC heating element, which is composed of PTC ceramic heating element and aluminum tube. This type of PTC heater has the advantages of low thermal resistance and high heat exchange efficiency. It is an electric heater with automatic constant temperature and power saving. The outstanding feature lies in the safety performance. Under any application, the phenomenon of "redness" on the surface of electric heating tube heaters will not occur, which may cause burns, fires and other safety hazards.
It is composed of galvanized outer pressure plate, stainless steel corrugated spring sheet, galvanized inner pressure plate, single-layer aluminum heat sink, ptc heating sheet, double-layer aluminum heat sink, nickel-plated copper electrode terminal and pps high temperature plastic electrode sheath. This product adopts U-shaped corrugated heat sink, which improves its heat dissipation rate, combines the advantages of adhesive and mechanical, and fully takes into account the various thermal and electrical phenomena of ptc heating elements during operation, and its bonding force is strong. , Excellent heat conduction and heat dissipation performance, high efficiency, safety and reliability. This type of PTC heater has the advantages of low thermal resistance and high heat exchange efficiency. It is an electric heater with automatic constant temperature and power saving. One of its outstanding features lies in its safety performance. Even when the fan fails and stops, the PTC heater will not receive sufficient heat dissipation, and its power will automatically drop sharply. At this time, the surface temperature of the heater is maintained at about the Curie temperature ( Generally around 250°C), so as not to cause "redness" on the surface of heaters such as electric heating tubes.
PTC heater principle
The constant temperature heating PTC thermistor has the characteristics of constant temperature heating. The principle is that the PTC thermistor self-heats after being powered on to make the resistance enter the jump zone. The surface temperature of the constant temperature heating PTC thermistor will maintain a constant value. This temperature is only the same as the PTC The Curie temperature of the thermistor is related to the applied voltage, but basically has nothing to do with the ambient temperature. PTC heater is a heating device designed by using constant temperature heating PTC thermistor constant temperature heating characteristics. In the occasion of small and medium power heating, PTC heater has the advantages of constant temperature heating, no open flame, high heat conversion rate, minimal influence of the power supply voltage, long natural life and other traditional heating elements. The application in electric heating appliances is becoming more and more popular. Favored by R&D engineers. The constant temperature heating PTC thermistor can be made into a variety of shapes and structures and different specifications, the common ones are wafer shape, rectangle, strip shape, ring and honeycomb porous shape. Combining the above-mentioned PTC heating elements and metal components can form various forms of high-power PTC heaters.
PTC heaters are divided by conduction method
(1) PTC ceramic heater based on heat conduction. It is characterized by a multi-layer heat transfer structure such as an electrode plate (electrical conductivity and heat transfer), an insulating layer (electrical insulation and heat transfer), a thermally conductive heat storage plate (some with thermally conductive glue) mounted on the surface of the PTC heating element, and the PTC element The heat emitted is transferred to the heated object.
(2) Various PTC ceramic hot air heaters that conduct convective heat transfer with the formed hot air. It is characterized by large output power, and can automatically adjust the blowing temperature and output heat.
(3) Infrared radiation heater. Its characteristics actually use PTC components or heat conduction plates
The rapid heat from the surface directly or indirectly stimulates the far-infrared paint or far-infrared material that touches the surface to radiate infrared, which constitutes a PTC ceramic infrared radiant heater.
PTC heaters are divided according to structural characteristics
(1) Ordinary and practical PTC ceramic heater. Such appliances mainly include: electric mosquito repellent, hand warmer, dryer, electric heating plate, electric iron, electric soldering iron, electric heating adhesive, curling iron, etc. Its characteristic is that the power is not large, but the thermal efficiency is high and it is very practical.
(2) Automatic constant temperature PTC heater. Such appliances mainly include: small crystal device constant temperature bath, constant temperature incubator, electronic thermos bottle, incubator, thermos cup, insulation plate, insulation cabinet, insulation table, etc. It is characterized by automatic heat preservation, simple structure, good constant temperature characteristics, high thermal efficiency, and wide operating environment temperature range.
(3) Hot air PTC heater. Such hot air PTC heaters mainly include: small warm air heaters, hair dryers, heating rooms, dryers, drying wardrobes, clothes dryers, industrial drying equipment, etc. It is characterized by high output hot air power, rapid heating, safety, and automatic adjustment of air temperature and power consumption.
PTC's role in air conditioning
The PTC corrugated heater of air conditioner is a kind of self-controlling temperature heater.
1. Constant temperature heating PTC thermistor has constant temperature heating characteristics. The principle is that after the PTC thermistor is powered on, the resistance value will enter the jump zone by self-heating. The surface temperature of the constant temperature heating PTC thermistor will maintain a constant value. It is related to the Curie temperature of the PTC thermistor and the applied voltage, but basically has nothing to do with the ambient temperature.
2. The PTC heating element is a heating element designed by using the constant temperature heating characteristic of the PTC thermistor. In the occasion of low and medium power heating, PTC heating element has the advantages of constant temperature heating, no open flame, high heat conversion rate, minimal influence of the power supply voltage, long natural life and other traditional heating elements. The application in electric heating appliances is becoming more and more popular. Favored by R&D engineers.
3. The constant temperature heating PTC thermistor can be made into a variety of shapes and structures and different specifications, the common ones are wafer shape, rectangle, strip shape, ring and honeycomb porous shape, etc. Combining the above-mentioned PTC heating elements and metal components can form various forms of high-power PTC heating elements.
There are many factors in the surface temperature of the PTC heater, so the accuracy of the surface constant temperature cannot be very high. In occasions where high temperature control accuracy is required, PTC heaters and temperature controllers can be used. When the external temperature controller fails, the heating surface temperature of the PTC heater will not exceed the set constant temperature, and it has an over-temperature protection function.