The weighing module consisting of load cells has its own unique features in chemical enterprises because of its flexible assembly and low price.
I. Weighing module and its characteristics 1. Introduction of weighing module: Weighing module is a practical structural accessory for sensors. It consists of a top plate, a substrate, a load cell, a load support column and a support bolt. According to the load support column and the top plate, it is divided into three types: fixed type, semi-floating type and floating type. In a weighing system, a fixed module, a semi-floating module, and the rest are filled with floating modules, generally divided into three sets and four sets. Three sets are used for three-point support and four sets are used for four-point support. The weighing module can be easily installed on containers of various shapes and is suitable for retrofitting existing equipment. Whether it is a container, a hopper or a reaction kettle, or a weighing module, it can be turned into a weighing system.

2. Features of the weighing module: Compared with the off-the-shelf electronic weighing instrument, the biggest feature of the weighing module is that it is not limited by the site, flexible in assembly, convenient in maintenance and cheap. The ground scale has a certain scale for the weighing platform, and the weighing module is installed on the support point of the container, and no additional land occupation is required. It is especially suitable for applications where multiple containers are installed side by side and the site is narrow. The range and division value of the electronic weighing instrument have certain specifications, and the weighing system consisting of the weighing module, the range and the division value can be set within the range allowed by the instrument, and can be set as needed. The weighing module is easy to repair. If the sensor is damaged, the support screw can be adjusted to lift the scale body. The sensor can be replaced without removing the weighing module. In addition, due to the simple structure of the weighing module, the weighing system is composed of the weighing module, and the investment is relatively small.

Second, the application of weighing modules in chemical enterprises: chemical enterprises use a large number of storage tanks and metering tanks in the material storage and production process. However, two problems are commonly encountered, one is the measurement of materials, and the other is the control of the production process. According to our practice, the application of the electronic weighing module can be better solved. 1. Weighing module is applied to material metering: Generally speaking, most of the current tank liquid metering is measured by a ruler or a flow meter. But both methods are measured in volume and then converted to weight based on the density of the liquid. Because the density is related to temperature and other factors, the error is relatively large. Although there are mass flow meters at present, they are rarely used by ordinary companies because of their high price. Therefore, it is more economical and practical to use the electronic weighing module to directly weigh the weight of the materials. 2. Weighing module Weighing module is applied to liquid level indication and control. The liquid level is an important control parameter for the chemical production process. Generally, the liquid level indication is generally used to convert the liquid level signal into a standard electric signal or a gas signal to be transmitted to the control room in addition to the liquid level indicating instrument on site. However, in addition to the error of the liquid level caused by the change in density, the method may cause a false liquid level due to crystallization or clogging of the material, and may even cause an accident in severe cases. In addition, because the measuring part of the transmitter is directly in contact with the measured medium, for some corrosive media, expensive corrosion-resistant materials are required. The weighing module does not directly contact the measured medium, and none of the above disadvantages exist. And the weighing display can be selected with an analog output interface, connected to the recorder, regulator, to achieve automatic recording and control. 3. The weighing module is used in applications where the amount of material is strictly required. There are some production processes that have strict requirements on the amount of feed. Many companies put the metering tank directly on the ground to control the amount of feed. However, on-ground balance inspection or inspection, it is necessary to hoist the measuring tank with lifting equipment, which is more troublesome. If the electronic weighing module is used, since the measuring tank itself is used as the scale body, there is no lifting problem, and the maintenance is convenient.

Third, the weighing module purchase, installation, debugging Notes: 1. Optional considerations: the purchase of the weighing module, generally based on the support point of the container to select the scale of 3 sets or 4 sets of modules, Due to the self-weight of the scale body (container), vibration shock, and partial load, it is generally selected according to the following rules. Multi-sensor static weighing system: fixed load (weighing platform, container, etc.) + variable load (load to be weighed) ≤ selected sensor rated load × number of sensors × 70%, 70% of which is considering vibration, Shock and partial load factors are added. In addition, it is necessary to pay attention to whether there are explosion-proof requirements, flammable and explosive, then use explosion-proof sensors.

2. Installation precautions: (1) Pay attention to the horizontal adjustment, including the horizontal adjustment between the installation plane of a single module and a set of weighing modules.
(2) When welding, the sensor can't pass current. When welding the top plate, the ground wire should be connected to the scale body. When welding the bottom plate, the ground wire should be connected to the foundation to prevent damage to the sensor.
(3) If there is a conveying pipe on the scale body, it should be replaced with a hose, or the connecting pipe should be as long as possible to prevent them from eating the actual load of the sensor and causing errors.
(4) A weight calibration table is to be welded to the container for verification. There is generally no place to place the weight on the container, and it is necessary to weld a platform to place the weight. Usually welded under the container for easy weighting up and down.
(5) The junction box must be protected from moisture, and the excess holes should be plugged with a sealing plug. If the junction box is installed outdoors, a protective box must be added to prevent rain. In the event of a failure due to moisture in the junction box during use, it must be given sufficient attention.
3. Precautions for debugging: (1) Before commissioning, it is necessary to check whether the top nut of the support screw of each weighing module has been loosened, and whether the sleeve is in a free state. Otherwise, a large error will occur, and even the weighing cannot be performed.
(2) When debugging, check whether the factory setting value of each parameter meets the actual needs, especially the “power-on zero” parameter. Generally, it is set to “automatically clear” when it leaves the factory. It is better to change it on the container scale. In order to prevent automatic turn-on of the machine, it is prevented that the weight of the material of the container is cleared and lost when the machine is turned on again due to power failure.
(3) Range setting does not refer to the rated total load of a set of weighing modules, nor the weight of the container itself, but should be selected according to the maximum material weighing, from the indexing and dividing values given in the manual. Weigh the weight as a range. (4) The power supply voltage of the weighing display must meet the requirements. If the voltage is unstable and exceeds the allowable range, digital drift will occur. It is best to use a regulated power supply. Because the weighing system consisting of electronic weighing modules facilitates the process automation weighing and is easy to be networked with computers, it is bound to be more and more widely used in chemical companies.