On-line weighing control system of radio frequency-hot air combined drying equipment

Abstract

The invention belongs to the technical field of radio frequency drying and particularly relates to an online weighing control system for radio frequency-hot air combined drying equipment. Aiming to realize self-adaptive control of radio frequency output power and air speed in a radio frequency-hot air combined drying process, the online weighing control system for the radio frequency-hot air combined drying equipment comprises an execution device, an online weighing device and a weighing control device. The online weighing control system is simple in structure and convenient to use, mass of materials can be acquired in real time, the material drying rate can be obtained according to mass change, then the execution device is controlled by the weighing control device to adjust polar plate spacing or the air speed automatically, moisture diffusion in the materials is matched with outside convective mass transfer, and the material drying rate can be increased greatly. Besides, influence of external environmental conditions on state parameters of the materials and a drying chamber in material pick-and-place processes during manual intermittent weighing and in radio frequency equipment starting and stopping processes is avoided, and the control precision is improved.

Description

technical field [0001] The invention belongs to the technical field of radio frequency drying, and in particular relates to an online weighing control system of radio frequency-hot air combined drying equipment. Background technique [0002] Radio frequency is an electromagnetic wave with a frequency of 3kHz to 300MHz, which can penetrate into the material, causing the polar molecules and charged ions inside the material to oscillate and migrate, rub against each other, and then convert electrical energy into heat energy. Because the heat energy directly generated inside the material to be dried promotes the evaporation of water in the material, it is possible to dry the material quickly, uniformly and with guaranteed quality. Therefore, it has a good application prospect in the field of material drying. However, in practical applications, due to the absorption or reflection of radio frequency energy by metal materials, the general weighing equipment cannot be placed direct...

AI Technical Summary

Problems solved by technology

However, in practical applications, due to the absorption or reflection of radio frequency energy by metal materials, the general weighing equipment cannot be placed directly between the two polar plates of the drying device. The material needs to be taken out and weighed after the radio frequency stops heating, and then the relevant parameters are calculated and the equipment is adjusted. parameters, the operation is extremely inconvenient

At the same time, during the process of picking and placing materials and opening and closing radio frequency equipment, external environmental conditions will inevitably have an impact on the state parameters (such as temperature, relative humidity, etc.) of materials and drying chambers, making it impossible to achieve precise control of the drying process

At present, although some online weighing systems for radio frequency and microwave drying can detect the quality change of materials in real time, the weighing object is the entire drying equipment. Compared with drying equipment, the mass of materials accounts for a small proportion, so the obtained materials will The mass error is large and the measurement accuracy is not high

There are also some weighing systems that use hanging weighing. For radio frequency-hot air combined drying equipment, the hanging weighing system will be affected by the movement of the upper plate and the wind speed.

Images