1 Introduction

In many industries in the reactor tank weighing dosage accuracy or not is related to product quality is an important factor, so weighing module as a reactor tank dosage weighing device, it can be in the case of not touching the material, weighing out the weight of the material required with the traditional sensors compared to it has a good stability, high accuracy and easy to install and to prevent the measurement error due to improper installation and so on, and to reduce the impact of external environmental factors on the weighing. With the continuous development of China's industrial automation production, weighing module is widely used in many industries.

2 characteristics and working principle of weighing module

Weighing module is a high-precision sensors, load transfer devices and installation of coupling devices such as a combination of new weighing unit, this device is not subject to the installation conditions and environmental impact, and to ensure the stability and accuracy of the sensor at the same time, but also to avoid the installation of the reasons for weighing errors caused by the risk of error. The weighing module is mainly composed of a top plate, a bottom plate, a load cell, a load cell bearing head and support bolts. The weighing module is characterized by its compact design and reasonable simplicity, all parts do not need to be welded and there are no other additional accessories. Since all weighing modules are manufactured, installed and tested according to standards, they can be easily and quickly installed and commissioned.

A fixed weighing module is usually used in combination with other floating and semi-floating weighing modules in automatic kettle dosage systems, which makes it possible to ensure that the load cell's stress point on the weighing module remains unchanged when the weighing control system is subjected to displacement caused by thermal expansion and contraction. This ensures the high accuracy and long-term stability of the load cells, while preventing measurement errors caused by improper installation.

The working principle is that the weighing module to generate and the weight of the kettle tank is proportional to the analog signal, and then the analog signal of each weighing module through the parallel convergence access junction box, we can according to the weighing module from the stress condition to the weighing module to regulate the output, and then the aggregated signals to the weighing display terminal to show the weight data. Junction box and weighing display control terminal should be based on the requirements of the use of the site to choose a different level of protection and explosion-proof grade.

3 Installation and commissioning of weighing module

In the kettle weighing system, the selection, installation and commissioning of weighing module will be directly related to the measurement accuracy of the whole metering and dosage system, therefore, the design and installation should be rigorous and prudent. Weighing module material should be based on the use of the site environment to decide, such as if there is contact with corrosive chemical materials should be used stainless steel weighing module, should also take into account the requirements of explosion-proof. Weighing module in the installation of the kettle tank support point for the force point and support the rigidity and straightness to be good, its number is generally composed of 3 or 4, all weighing modules should be installed in the same horizontal plane and evenly distributed, so that the weight of the kettle tank can be uniformly distributed in the weighing module, so as to ensure that the weighing module is subject to uniform and vertical force, so that each weighing module to carry the force close to the same In order to minimize errors due to the influence of the support structure on the weighing module.

In the installation of the weighing module should be strictly prohibited welding welding operation, so as to avoid welding current through the weighing module and damage to the module in the weighing sensor, such as welding operation should be grounded directly to the kettle tanks, and in the welding must pay attention to the current circuit can not be allowed to pass through the weighing module in the weighing sensor in order to prevent damage to the weighing module sensor. And because in the actual use of the weighing module will be wind, vibration and other winter environment, thus affecting the measurement accuracy of the weighing module. In the reaction kettle tank weighing and batching system, raw materials and finished products in and out of the pipeline transportation is the main, so the pipeline and mixing tank connection is particularly important, if the connection is not appropriate will affect the normal use of the mixing tank weighing and batching system, resulting in a large deviation. Therefore, the pipeline connected with the reactor tank should be connected with hose, and the support of the pipeline should be installed on the frame of the mixing kettle tank, and should be laid horizontally in order to prevent the pipeline from the reaction kettle tank caused by the pulling force, resulting in errors, and to ensure that the weight of the reaction kettle tank is fully applied to the sensors of the weighing module.

The weight of the dosage kettle tank is converted into voltage signal by the weighing module and then transmitted to the weighing display controller for weight display through the junction box, and the junction box is the voltage signal output from each weighing module is synthesized, and then the weighing display will convert the voltage signal transmitted from the junction box into the corresponding weight display. Therefore, in the reaction kettle tank weighing and dosage system installation is completed, should be mixed kettle tank weighing and dosage system for debugging calibration, now commonly used debugging calibration methods are standard weights method, alternative method and standard signal simulation calibration method. Standard weights method is the standard weights from zero gradually loaded to the maximum weighing, and then gradually unloaded to empty to calibrate, with this method of loading the results are the most accurate, but the requirements of the reaction kettle tank weighing and batching system equipped with a platform to place weights on the bracket or hooks and other devices. The alternative method is relatively simple, that is, in only a small number of weights for calibration, can only be calibrated with other alternatives, from the zero point of the empty scale with standard weights and other alternatives to repeat the comparison for calibration. There is also in can not use standard weights for calibration, can only be weighed in another high-precision scales on the mass of the alternative, and then put the alternative into the kettle tank weighing and dosage system for calibration, the alternative method is the current kettle tank weighing and dosage system calibration is usually used in the method of calibrating the standard signal simulation method is to use the standard signal source instead of the signal output of the weighing module to simulate the kettle tank weighing and dosage system of the empty scale value and full scale value. Empty scale value and full scale value, by adjusting the output of the standard signal source to calibrate the range, this method has a certain impact on the accuracy of the reaction kettle tank weighing and batching system, generally not used.

4 weighing module maintenance

Weighing module in the use of the process should be carried out regularly check, clean up the weighing module on the debris and materials to prevent jamming, check the weighing module in the limit is reliable, check the weighing module wiring security, firmness, should be carefully check the reaction kettle tank on the pipeline and bracket connection to prevent the impact of the drawback to ensure that the weighing module of the normal operation of the other, the reaction kettle tank weighing and dosage system must be installed to prevent the thunder and lightning protection device to prevent lightning damage to the sensors in the weighing module, so each weighing module must be well grounded.

5 Conclusion

Weighing module is widely used in reaction kettle tanks, it has easy installation, the influence of environmental conditions is small and has a stable and reliable, so that the development of the weighing module is very broad prospects.