The weighing module composed of weighing sensors has its unique application in food, chemical, and pharmaceutical enterprises due to its flexible assembly and cheap price.
1. Introduction to weighing module
The weighing module is a practical structural accessory used for sensors, consisting of a top plate, a bottom plate, a weighing sensor, and supporting bolts.
According to the different top plates, there are three types of structures: fixed, semi floating, and fully floating. In a weighing system, one fixed module, one semi floating module, and the rest are fully 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 various shapes of containers, suitable for retrofitting existing equipment. Whether it is a container, hopper, or reactor, with a weighing module, it can become a weighing system.
Compared with ready-made electronic scales, the biggest feature of weighing modules is that they are not limited by the site, are flexible in assembly, convenient in maintenance, and are inexpensive.
The ground scale requires a certain floor area due to its weighing platform, while the weighing module is installed on the container support and does not require additional floor space. Especially suitable for situations where multiple containers are installed in parallel and the site is narrow. The range and graduation value of electronic scales have certain specifications, and the weighing system composed of weighing modules can be set within the allowable range of the instrument according to needs. The weighing module is easy to maintain. If the sensor is damaged, the support screw can be adjusted to lift the scale body, and the sensor can be replaced without the need to remove the weighing module. In addition, the structure of the weighing module is simple, so the weighing system is composed of weighing modules, and the investment is relatively small.
2、 Application of weighing module in chemical enterprises
Chemical enterprises extensively use various storage and measurement tanks in material storage and production processes, but they generally encounter two problems: one is the measurement of materials, and the other is the control of the production process. According to our practice, the application of electronic weighing modules can effectively solve the problem.
1. The weighing module is applied to material measurement
Generally speaking, the measurement of liquid in storage tanks is mostly done using a scale or flow meter. However, both methods are based on volume measurement and then converted into weight based on the density of the liquid. Due to the relationship between density and temperature factors, the error is relatively large. Although there are mass flow meters currently available, they are rarely used due to their high prices. Therefore, using electronic weighing modules to directly weigh materials is more economical and practical.
2. The weighing module is applied for liquid level indication and control
Liquid level is an important control parameter in the chemical production process. Usually, in addition to on-site liquid level indicating instruments, a transmitter is used to convert the liquid level signal into a standard electrical signal or steam signal for remote transmission to the control room. However, this method not only causes liquid level errors due to changes in density as mentioned earlier, but also may cause false liquid levels due to material crystallization, blockage, and other factors, which can even lead to accidents in severe cases. In addition, due to the direct contact between the measuring part of the transmitter and the measured medium, for some corrosive media, expensive corrosion-resistant materials need to be selected, while the weighing module does not directly contact the measured medium, and the above drawbacks do not exist. Moreover, the weighing display instrument can be selected with an analog output interface, connected to the recorder and regulator, to achieve automatic recording and control.
3. Module application in situations with strict requirements for feeding quantity
Some production processes have strict requirements for the feeding amount, and many enterprises directly place the measuring tank on the ground scale to control the feeding amount. But when repairing or calibrating the ground scale, it is more troublesome to use lifting equipment to lift the measuring tank down. If an electronic weighing module is used, as the measuring tank itself serves as the weighing body, there is no lifting problem and maintenance is more convenient.
1. Precautions for purchasing
The selection of weighing modules is generally based on the supporting points of the container, and a weighing system is composed of three or four modules. Due to factors such as the self weight of the weighing body (container), vibration and impact, and eccentric load, a multi sensor static weighing system is generally selected according to the following rules:
Fixed load (weighing platform, container)+variable load (load to be weighed)≤ Select a sensor with a rated load of x70%, where 70% of the coefficient is added considering factors such as vibration, impact, and unbalanced load.
In addition, attention should be paid to whether there are explosion-proof requirements. In flammable and explosive situations, explosion-proof sensors should be selected.
2. Installation precautions
Pay attention to horizontal adjustment, including the installation plane of a single module and the horizontal adjustment between a set of weighing modules.
(1) When welding sensors, current cannot be passed through. When welding the top plate, the ground wire should be connected to the scale body. When welding the base plate, the ground wire should be connected to the foundation to prevent damage to the sensor.
(2) If there are feeding pipes on the scale body, they should be replaced with hoses or the connecting pipes should be as long as possible to prevent them from eating the actual load of the sensor and causing errors.
(3) To weld a weight verification table on the container for verification, there is usually no place to place weights on the container, and a platform needs to be welded to place weights. Usually welded below the container for easy lifting of weights.
(4) The junction box must be protected from moisture, and excess holes should be plugged with sealing plugs. If the junction box is installed outdoors, a protective box must be added to prevent rain. Faults caused by moisture in the junction box during use often occur, so sufficient attention must be paid.
3. Debugging precautions:
(1) Before debugging, it is necessary to check whether the top nut of the support screw of each weighing module is loose and whether the sleeve is in a free state. Otherwise, significant errors may occur and even weighing may not be possible.
(2) When debugging, it is necessary to check whether each parameter's factory setting value meets the actual needs, most of which are" Turn on and reset; The parameters are usually set to&quo; at the factory; Auto reset upon startup&# quo;, The setting of the container scale should be changed to&quo; Prohibit automatic reset upon startup&# quo;, To prevent the weight of materials in the container from being reset and lost when starting up again due to power outages and other reasons.
(3) The range setting does not refer to the total load of a weighing module, nor does it include the weight of the container itself. Instead, based on the maximum material weighing, select a range that is greater than or equal to the maximum range from the divisions and values provided in the instruction manual.
(4) The power voltage of the weighing display instrument must meet the requirements. If the voltage is unstable and exceeds the allowable range, it will cause digital drift. It is best to use a regulated power supply.
Due to the convenience of realizing process automation weighing and computer networking, the weighing system composed of electronic weighing modules will be increasingly widely used in chemical enterprises.
Sales Engineer - Miss Chen