The random error of high-precision belt weigher is very small, but the system error is more complex. The installation conditions and commissioning level of the belt weigher are the key to making good use of the belt weigher. An expert of the belt weigher came to China to give a lecture and said: "80% of the use of the belt weigher depends on the user's installation and maintenance.". This is an exaggeration to illustrate the importance of installation and maintenance. It is true that most of the technical content of the belt weigher is used well in installation, debugging and daily maintenance.
According to the installation and commissioning manual of the belt scale, the scale frame is installed on the belt that has been pre selected for the production and operation of the raw material conveying system, and the installation position of the scale frame is determined at the acquisition point. See the installation regulations of Xuzhou Sanyuan automatic belt weigher for details. Check whether all idlers in the weighing area (weighing section and auxiliary weighing section) meet the requirements. If they fail to meet the requirements, they must be repaired or replaced. The "three wire system" is commonly used for the "collimation calibration" of the symmetrical weight area. The "six wire system" is used by the installation and commissioning technicians of Xuzhou Sanyuan Automatic Weighing Business Department with 13 years of installation and commissioning experience. The weighing idler and the front and rear auxiliary idler are adjusted to be horizontal or slightly higher by 5mm to ensure that the belt in the weighing section is in good contact with the idler when there is no load.
The deflection of the belt varies with the size of the load. The length, width, thickness and material of the belt are different. Single idler weighing, multi idler weighing, lever weighing, suspension weighing and cantilever weighing are all rigidly specified with their height differences. Can they adapt to the changes in belt weighing? Can dynamic zero stability be guaranteed? The deflection of the belt should be the same at the same distance between the idlers and the same horizontal line, and the belt should be weighed from the original state.
High precision electronic belt scale
The installation and commissioning technicians of Xuzhou Sanyuan Automatic Weighing Business Department adopt the "six wire system", which also reduces the workload of on-site installation and commissioning. Since the belt width is 500mm, use a single line to adjust the weighing idler of the scale frame to the same horizontal line as the conveying idler, and adjust the vertical and horizontal limiting devices of the scale frame to keep the scale frame free from any stress. The adjustment of belt tension device is very important to control the sag of belt deflection, which belongs to system adjustment, while the adjustment of weighing idler is local adjustment. The belt conveyor is equipped with a screw type tension tensioning device, which can adjust the belt deflection within the tolerance range, and also solve the problem of belt deviation. Four columns and supports are added to reinforce the belt conveyor to solve the vibration problem, correctly complete the wiring of the load cell and speed sensor, actually measure the belt circumference with a tape, average the belt speed for three times, accurately set parameters, and the installation and commissioning work is completed.
Through comprehensive analysis, Xuzhou Sanyuan Automation Weighing Business Department believes that the purpose of raising the weighing idler is to make its idler better contact the belt, change the initial state of the belt, and form a "zero point migration". When the belt is loaded with a certain amount of materials, the belt will return to its original state for weighing. The principle of force and reaction force is used, which is the same as the statement that the idler in the weighing area is in a straight line when 50% of the force on the scale frame is applied.