Which electric hand warmer is safer to choose in cold winter?
Warm hand treasure
With over-voltage protection device. Choosing an electric hand warmer with overvoltage protection device can prevent the hand warmer from over-expanding, thus avoiding explosion. Overvoltage protection devices are usually divided into two types: built-in and external. The internal parts will be explained in the manual, and the external parts will be equipped with duckbill explosion-proof connectors.
Hand warmer is an automatic heating health care product developed by using physical and chemical principles. This product is very popular because of its novel and unique advantages, such as automatic heating, fun, practicality and so on-hand warmer has many functions, such as automatic heating, physical therapy, health care and so on.
Hand warmers can be roughly divided into three types: one is to heat by heating water, which is also commonly known as hot water bottles. Different from the traditional hot water bottle, the electric hot water bottle saves the trouble of adding water. Just plug in the power supply and wait 10 minutes to raise the temperature. In fact, the water inside is boiling, so the temperature will be very high. One is to generate heat through chemical reaction, which is the type of hand warmers on the market. The temperature of heat generated by the contact of internal chemicals is about 40℃. The other is to use the function of lithium battery, the internal heating chip heats up, and the USB interface charges and discharges, similar to the mouse pad of hand warmer. Because of the function of lithium battery, it can also be used as a mobile power supply. Small size, easy to carry, the temperature can reach about 50℃.
Heating principle:
Appearance: a sealed plastic bag with transparent liquid and metal sheets inside.
1, use-gently bend the metal sheet in the bag, and the liquid in the bag will appear crystal (blue translucent), harden and become solid. The fever temperature is about 50 degrees (about 1 hour).
2. Standby —— After use, put it in boiling water for 10 minute until the crystal completely recovers to a transparent liquid, and then use it again after cooling.
3. The product can be reused according to the above method.
In hot summer, you can change it into a cold-proof treasure, which can be used for heatstroke prevention and cooling like an ice pack, but it needs to be frozen in the refrigerator before use.
To understand the principle of hand warmers, we must first know what a supersaturated solution is. At a certain temperature, the solubility of solute in solvent is constant, for example, the solubility of salt (sodium chloride) in water is 36g/ 100mL water at room temperature. When the concentration in a solution is equal to its solubility, this solution is called a saturated solution; When the solubility of a solution is higher than its solubility, it is called supersaturated solution. The liquid in the warm handbag is a supersaturated solution of sodium acetate.
Because the concentration of supersaturated solution is too high, it is unstable. When a metal is twisted, a slight vibration is enough to crystallize the solute and turn it into a relatively stable solid. However, this process is exothermic, so the warm handbag begins to heat up.
One advantage of warm handbags is that they can be recycled. As long as the warm handbag is heated in boiling water for about 10 minutes, the condensed solute will dissolve again; This is because when the temperature rises, the solubility of solute becomes larger. In the process of dissolution, the solute undergoes endothermic reaction and becomes supersaturated solution again.
It is said that the packaging seems to be made of PVB, which is non-toxic at room temperature, but it will precipitate toxic substances after heating. This product has not been tested by the State Quality Supervision Bureau, so its safety needs to be considered.
Usage characteristics:
First, lithium battery is used to supply energy, which has large capacity and is more environmentally friendly. It can be recycled, charged for 3-4 hours and kept at room temperature for 6-7 hours (the specific time depends on different models).
Second, the latest ceramic heater is used internally, which is healthy, conducts heat through infrared rays, promotes blood circulation, accelerates metabolism, improves immunity and has no electromagnetic radiation. It is an ideal product for relieving pain, protecting health and keeping warm in winter for patients with arthritis, scapulohumeral periarthritis, lumbago and leg pain, rheumatism and rheumatoid diseases, aversion to cold and discomfort, cold limbs and trauma.
Three, small and lovely appearance, elegant packaging, is a good gift for relatives and friends.
Fourthly, it has USB reverse charging function, which can charge all kinds of digital products and is suitable for home life, work and going out.