1. Overview
The hot air circulating oven, also known as the electric air blower drying oven (hereinafter referred to as the drying oven), is an upgraded model of SY841, which pays more attention to the energy-saving and safety of products. It adopts the new energy-saving and environmental-friendly heating technology promoted by the State Economic Commission, and when it is absorbed by the heated object, it can be directly converted into heat energy, so as to obtain a rapid drying effect, and achieve the purposes of shortening the production cycle, saving energy and improving product quality. It is convenient to use and has obvious effect, and it is an ideal drying equipment with broad prospects. Suitable for production workshops or laboratories in industry and agriculture, medical and health care, plastic machinery, universities and scientific research departments.
II. Structure
The drying box is made of angle steel and thin steel plate. Glass fiber is filled between the shell and the working room for thermal insulation. The heating system is installed at the top of the working room. This type of drying box with air blast can effectively avoid the gradient temperature difference and temperature overshoot in the working room, and can improve the temperature uniformity in the working room.
3. Temperature control
1. This type of drying oven adopts a digital temperature controller with P, I and D control modes, and is equipped with a thermal element probe to form automatic constant temperature control. Sensitive temperature control accuracy, temperature selection, normal temperature to 25℃, arbitrary selection and setting. The temperature in the working room can be read directly from the instrument.
2. Timing control: the timing range (S-99.9H), the control mode (startup timing or constant temperature timing) can be selected according to the customer's work requirements, and the heating will be automatically turned off when the set time is reached. When setting, the dip switch can be directly dialed on the control panel, in which the code unit is (s seconds m minutes h hours).
the temperature control part is the core part of the electric drying oven, which mainly compares the temperature signal measured by the sensor with the set value. If the value measured by the sensor is lower than the set value, the temperature controller outputs a pulse signal, which triggers the conduction of the SCR control board to make the drying oven in a heating state; if it is higher than or equal to the set value. The SCR stops working, and the heating system is disconnected. The products of our company adopt PID controller, which contains three basic control laws, namely, proportional (P), integral (I) and fractional (D) control laws, and each control law plays a different role, which can be applied separately or in combination. The controller adopts the most effective control method-anti-integral saturation PID control method for the control object with large time delay, that is, when the measured value deviates from the set value, the instrument output is heated continuously until the measured value is equal to the set value. Because of the function of D, the instrument has advanced adjustment function, which improves the dynamic control of the instrument and shortens the adjustment time. It is displayed by LCD, and the sensor is commonly used Pt1 with on-off output. Therefore, the controller is equipped with AC contactor, original switch, fuse and alarm lamp to form a control loop, that is, AC22V is connected to the "normally open" terminal of the AC contactor, and the switch value of the temperature controller controls the pull-in coil of the AC contactor, thus achieving the control purpose.
IV. The box body part
adopts streamline arc design, the shell is made of cold-rolled steel plate, and the surface is electrostatically sprayed with plastic; The inner containers are all made of mirror stainless steel; The height and number of shelves in the studio can be adjusted at will according to the user's requirements; Adopting EBM fan (1-speed adjustment) and circulating a small amount of wind is conducive to drying fine or powder-related articles and making the temperature in the box more uniform, and at the same time accelerating the evaporation of water vapor from the articles in the box to the air outside the box to improve the drying efficiency; Reasonable air duct and circulation system make the uniformity change in the studio small.