Design And Research Of Climate Chamber For VOC Detection Of Wood-based Panels For Furniture

Volatile organic compound(VOC)released from wood-based panels for furniture which is extremely harmful to human health.In recent years,it has received domestic and foreign attention.The latest promulgated national standard GB18580-2017 stipulates that the climatic chamber is the only method for detecting the formaldehyde emission in wood-based panels and finishing products of interior decoration.The climate chamber is a non-destructive detecting equipment that can provide constant temperature,relative humidity,air flow rate and ventilation rate.In response to the latest national standard,this article designs and studies the climate chamber,including control system,purification system and chamber structure.The main work and conclusions are as follows:(1)The control system uses real-time formaldehyde monitoring and control scheme with PLC as the core,which is composed of software design,hardware selection and human-computer interaction interface design.The temperature control adopts the segmented temperature control method with fuzzy control algorithm as the main body and the PID self-tuning algorithm precise control.The humidity control uses the dew point humidity control method with constant humidity ratio.Through the control system verification experiment,it is concluded that the PID self-tuning function can reduce the overshoot of the temperature control and the response time.The experiment proves the feasibility of the designed control system.(2)The purification system adopts a three-stage purification scheme mainly based on physical adsorption: the first stage is coarse filtration.The second stage is water washing filtration.And the third stage is adsorption filtration.Based on the purification scheme,a purification system verification bench was developed.According to the purification effect of VOC and formaldehyde,granular activated carbon and activated carbon fiber were selected for contrast experiment.The experiment showed that the purification result of activated carbon fiber was purer,and 240 g activated carbon fiber can meet the national standard and save cost.(3)The chamber structure is divided into a test chamber and an equipment chamber: the test chamber adopts the structure of the inner cabin and the interlayer,which is used to place the wood-based panels for furniture being tested;the equipment chamber is used to place other components,and the dew point humidity control water tank uses a combination of water bath humidification and atomization humidification to humidify the gas.Aiming at the layout of the climate chamber,Ansys Fluent software was used to analyze the temperature field distribution of the climate chamber.It is concluded that the upper and lower layouts of the test chamber and the equipment chamber are more ergonomic,while avoiding the influence of the heating equipment on the temperature of other equipment.