Electrothermal constant temperature drying ovens are also commonly referred to as ovens. It is used to dry samples, reagents, vessels, sediments, and to measure wet water. The heating element is a heating wire, which can be used up to 200 ° C, but the common temperature is between 100-1501:.
There are two commonly used ovens. One type of heat conduction in the box is by natural convection, and the heat source of the oven is the electric heating wire at the bottom of the oven. The uniformity of the temperature in the oven has a great relationship with the ventilation fL of the top plug thermometer. If the ventilation hole is properly adjusted, the temperature difference between the upper layer and the lower layer in the box is smaller. Another method of mechanical blasting makes the temperature inside the box uniform, so it is also called electric blast drying oven. The heating wire can be at the bottom or side (side heat type), because the ventilation is better, the temperature inside the box is more uniform, and the baked object can be dried quickly.
The heating electric heating wire is divided into two groups, one is auxiliary heating, and it is urgently needed to heat up to a high temperature in a short time; the other is used to maintain a constant temperature, and the heating unit is connected with the automatic temperature control system.
Some new ovens use digital temperature display regulators to automatically control temperature, easy to use, control sensitive, stable operation, and temperature display is intuitive and accurate. Some products also have an over-temperature protection device.
Oven use precautions:
(1) The drying oven should be placed on a stable, sturdy concrete platform to prevent tilting, vibration and corrosion. Can not be close, source, should not be exposed to sunlight, and can not store flammable and explosive materials nearby.
(2) According to the power consumption of the drying box, a sufficient iron shell power supply knife is installed in the power supply line for drying. The power supply voltage must not exceed the rated voltage of the dry box and be grounded with a wire that is twice as thick as the power line.
(3) Drying boxes generally have no explosion-proof equipment and cannot be used for drying with flammable, explosive and corrosive substances such as volatile chemical solvents, low-concentration explosive gases, low ignition points.
(4) When placing baked goods in the box, do not crowd, and leave a blast to the space to facilitate the air swirling flow to make the indoor temperature uniform. Promote humid air from the top of the tank. Do not place objects on the heat sink to avoid affecting the upward flow of hot air.
(5) Do not hit the temperature sensing element on the upper left side of the box to avoid affecting the sensitivity of the controller.
(6) The baked goods should be placed in an appropriate container, and then placed on the partition in the oven. The baked object should never be placed on the bottom plate of the oven. The bottom plate is directly heated by the heating wire, and the temperature is much higher than the oven. Controlled temperature. It is best to bake items of the same nature in the same oven at a temperature not exceeding the maximum use temperature of the oven.
(7) The inner and outer layers of the box are always kept clean. When not inspecting, the side door should not be arbitrarily removed, and the original electrical circuit cannot be arbitrarily changed.
(8) If the control part is normal after the power is turned on but the temperature inside the box does not rise, the door should be opened, the heat sink should be removed, and the heating wire should be checked for cracks or poor contact. If so, tighten the loose screws or replace the heating wire.
(9) The rod type temperature controller has been used for a long time, and it is easy to cause contact failure at the contact point. It can be gently rubbed with fine sandpaper to make the contact point tightly contact and no spark is generated.
(10) When the rod temperature control device and relay are used to control the temperature, if the relay is found to have intermittent “click†sound, the contact point of the controller should be wiped clean with a clean dry cloth to eliminate it. If the relay is found to have a continuous “beep†or jitter, indicating a capacitor failure or short circuit, a new capacitor should be replaced.
(11) When using rapid auxiliary heating, the staff cannot leave the site and should constantly observe the temperature rise. When the temperature is raised to the desired temperature, turn the switch to the constant temperature system.
(12) When using a non-blasted oven, the thermometer should be inserted closer to the baked object to more accurately indicate and control the temperature.
(13) The top exhaust valve of the box is generally about 1Omm, and should be closed in time to avoid entering the humid air and dust.