Laboratory electric stove model, appearance

Electric cooker / electric stove electric stove and gas lamps, the same as the laboratory is commonly used heating equipment. Electric stoves mainly rely on a resistance wire (commonly used nickel-chromium alloy wire) to generate heat by passing an electric current. This resistance wire is often referred to as a hotplate wire. There is also a kind of electric furnace can be adjusted to different calorific value, often called "universal electric furnace". Its appearance is shown in Figure 1. The hotplate is at the top and a single-pole multi-position switch is mounted below the hotplate. There are several contacts on the switch, and an additional resistor is installed between each two contacts. The additional resistor is sleeved with several segments of porcelain tubes to avoid contact with each other and with the furnace shell causing short circuit or leakage injury. Through the rotation of the sliding metal plate, the additional resistance in series with the furnace wire can be changed to adjust the intensity of the current through the wire, so as to achieve the purpose of regulating the heat generated by the electric furnace. When the metal slide 2 is at the disconnection point 3, the circuit is closed and the electric stove is in the closed position. When the metal slide turns to contact point 4, all additional resistors are connected in series with the furnace wire. At this point the total resistance is maximum and the current through is minimum, so the furnace wire heats up the least. When the metal piece is turned to contact point 5, the additional resistance is reduced by half, the current strength is moderate, and the heat released by the furnace is moderate. When the metal plate turns to contact point 8, the additional resistance is zero, the current intensity reaches the maximum, the heat emitted by the furnace also reaches the maximum. If the laboratory does not have a general-purpose electric furnace, you can also connect the ordinary electric furnace to the autotransformer of equal or greater power. Adjust the output voltage, you can arbitrarily change the current intensity, that is, arbitrarily change the heat generated by the furnace, more convenient than the universal electric furnace. Electric heating plate and electric heating jacket electric heating plate is actually a closed electric furnace, usually rectangular or round, with adjustable temperature. There are many objects being heated at the same time on the plate and there is no open flame. The electric hot plate is a routine ablation equipment recognized and accepted by domestic laboratories in the past 10 years. With the advantages of good temperature control, high stability and safety, the electric heating plate can largely help experimenters solve some problems faced by electric furnace ablation. However, electric heating plates have the disadvantages of high energy consumption, low thermal energy utilization, small effective heating area, limited number of samples, and poor uniformity of experimental results. The electrically heated jacket is a special equipment for heating round-bottomed flasks for distillation. The shell is made into a hemispherical shape, and the interior is composed of electric heating wire, insulating material and insulating material. According to the size of the flask, choose the appropriate electric heating jacket, often connected to the autotransformer to regulate the desired temperature. Precautions for the use of electric furnace, electric heating plate and electric heating jacket (1) The voltage of the power supply should be the same as the voltage specified for the electric furnace, electric heating plate and electric heating jacket itself. (2) When the heating container for glass or metal products, the electric furnace should be padded with asbestos mesh, to prevent the glass due to uneven heating and rupture, as well as metal containers in contact with the wire of the electric furnace and short-circuit electric shock. (3) The use of electric stoves, electric heating plates, electric heating jacket should not be too long a continuous working time, so as not to affect its service life. (4) Often keep the electric furnace tank clean.