Faults and solutions of hot air circulation oven

As a professional and efficient oven product in the oven industry, hot air circulation oven has been favored by manufacturers and customers since it was put on the market Today, let's have a look If there is a problem with hot air circulation oven, how can we solve it? What is the cause of the failure? 1 Description of fault phenomenon: close the air switch of the circulating oven, set the heating temperature of 250 ℃, over temperature alarm temperature of 260 ℃ according to the operation manual of the oven, and start the automatic operation program after the insulation time of 1H The indicator lights of the circulating fan, air inlet fan, butterfly valve and heating of the oven will light up in sequence, indicating the normal operation of the program After heating for 2.5h, the temperature still can not reach the set value If the heating time is too long, the heated glass container will be fragile and the broken bottle rate will increase At the same time, it causes energy waste and increases power consumption And the working cycle of the oven is lengthened, resulting in the failure to complete the process link on time under the two shift system of the normal production post, the process plan of the production task is almost missed, and the production cost is increased Normally, it takes 2.5h to heat the tank from room temperature to 250 ℃, and 6h for one working cycle 2 Fault analysis: first check the differential pressure gauge of the oven to determine whether the air speed in the hot air circulation oven is normal Understand whether the heated items in the hot air circulation oven are placed too intensively, whether the high-temperature efficiency filter is blocked, and whether the air volume regulating plate is modified After these reasons are eliminated, judge whether the circulation fan has faults, which causes the circulation of hot air circulation is not good, and the hot and humid air cannot be discharged normally Secondly, from the analysis of the fault phenomenon and the circuit principle of the oven, the hot air circulation oven can be heated, which shows that the output signal of gcd-23a intelligent computer temperature controller is normal, and the input and output signal of PLC is also normal 3 Fault detection and troubleshooting after the above fault analysis, it can be concluded that the control signal and adjustable parts are normal, and then we check from the following aspects First of all, check the PID adjustment parameters of gcd-23a intelligent computer temperature controller to see if it is operated by mistake, resulting in the change of setting parameters, so that the system has abnormal action PID parameters directly affect the regulation accuracy of the system, which is the core content of the control system design With proper PID parameters, PID control can calculate the control quantity of the system according to the error characteristics of the controlled process of the system, and obtain the corresponding output response characteristics by using proportion, integral and differential The control system can achieve satisfactory control effect Restore the normal setting value of PID parameter Secondly, check whether the circulating fan operates normally and whether the steering direction is correct If the fan reverses or the fan load is too large and the rotation speed is too slow, the hot air circulation will not be smooth When the fan reverses, the power supply of the fan can be switched between any two phases; when the speed of the fan is too slow, check from two aspects: (1) whether the power supply voltage is normal in electrical aspect, and whether there is phase loss or winding open circuit (2) in terms of machinery, check whether there are faults such as bore sweeping, vibration, bearing overheating, damage, fan blade loosening, case cleaning, etc It can be excluded according to the specific situation Check the solid-state relay and heater for local open circuit again Solid state relay (SSR), abbreviated as "SSR", is a new type of contactless switching device composed of all solid-state electronic components It uses the switching characteristics of electronic components (such as switching triode, bidirectional thyristor and other semiconductor devices) to achieve the purpose of making and breaking the circuit without contact and spark, so it is also called "contactless switch" SSR successfully realizes the control of weak signal (VSR) to strong current (output load voltage) Due to the partial open circuit after virtual connection or conduction of SSR, the 380V power supply is lack of phase and the heater cannot be heated completely The treatment method is to repair or replace the solid-state relay The partial open circuit of the heater will make the heating unable to work completely, causing the heating process to be too slow Repair or replace the heater Deal with the problem completely Close the air switch of the circulating oven, run the program according to the operation instructions of the oven After 2.5h heating, the oven reaches the set temperature, the time relay starts to count, and the oven enters the stage of intermittent heating and sterilization After heat preservation for 1 h, the hot air circulation oven starts to cool down, and after 2.3 h, the whole drying and sterilization cycle is finished, which fully meets the technical and technological parameters requirements provided by the oven.