The quality control system (QCS) mainly consists of two parts: measurement and control. The measurement part is the online detection of quantity, moisture, thickness, ash content, etc. The key to measurement is high-precision and high-stability sensors and scanning frames.
Application areas: papermaking, plastic films, non-woven fabrics, etc.
Sensors: quantitative sensors, moisture sensors, ash sensors, thickness sensors, etc.
The following uses paper technology to illustrate the key points of the quality control system (QCS): The dilution water valve is interlocked to control the horizontal quantitative, the sizing system is interlocked to control the vertical quantitative, and the drying system is interlocked to control the vertical moisture.
Basis weight refers to the weight of paper per square meter (g), which is controlled by changing the opening of the quantitative valve to change the absolute dry weight of the sizing. To ensure the stability of the quantitative, the stability of the concentration on the net must be ensured first, so there is a concentration adjustment loop before the sizing box.
Moisture refers to the moisture content of paper (%), which is controlled by changing the steam pressure in the drying cylinder and thus changing the drying capacity of the drying cylinder.
Thickness refers to the vertical distance (um) between the two surfaces of paper measured under a certain area and pressure. It is controlled by passing it through a rotating roller. Ash content refers to the remaining material after complete combustion of paper at a temperature of 925 degrees. It is usually expressed as a percentage, that is, the ratio of ash content to the absolute dry weight of paper. It is controlled by changing the mineral fillers applied in the pulp or coating ratio.
By controlling the basis weight, moisture, thickness and ash content of paper, the yield and quality rate of products can be improved, and raw materials and energy can be saved, thereby reducing costs.
System Structure
The control system adopts PLC + computer structure, the system resources are reasonably allocated, the measurement and control time is higher, the on-site display panel + on-site buttons are combined with computer operation to realize double insurance of control, ensuring the safe and stable operation of the system. The open system structure is convenient for communication with third-party systems, the powerful PLC function supports users to carry out secondary development, the high-precision quantitative valve ensures control accuracy, and the humanized interface design makes it easier for on-site personnel to master.
Scanning rack
The advanced and sturdy scanning frame is the basic platform for achieving online precise measurement and excellent control of the QCS system. The high-performance "O" type scanning frame of Gaoda is an important part of the QCS system. The BMCS scanning frame has an advanced structure, a high technical starting point, and can adapt to the measurement and control of different precision requirements. It is the only domestic product of its kind that has received free support from the National Innovation Fund. The scanning frame column adopts a "┥" type structural design, which effectively reduces the deformation of the beam.
The deformation of the beam affected by temperature is determined by its physical properties. Special structural design can only reduce the deformation. However, by using sensors to detect the deformation in real time and using software to compensate for the impact on the signal, the impact of the physical properties of the machine on quantitative moisture measurement can be fundamentally resolved.
The built-in high-precision Z-axis distance sensor measures the probe gap online in real time, and the real-time software compensates for the measurement error caused by beam deformation.
