Truck scale consists of three parts: scale body, sensor and instrument. The sensor directly affects the accuracy of weighing data, but because of the working environment, the weighing sensor will be affected more or less. Now I would like to share with you the possible impact of the working environment on the sensor, hoping to help you in the maintenance of the weighbridge.
(1) The high temperature environment causes some problems, such as melting of coating material, welding joint expansion, structural change of stress in elastomer and so on. For sensors working in high temperature environment, high temperature resistant sensors are often used; in addition, heat insulation, water cooling or air cooling devices must be added.
(2) Dust and humidity can cause short circuit to the sensor. In this environment, the sensor with high tightness should be selected. Different sensors have different sealing methods, and their sealing performance is very different. Common seals include sealant filling or coating; rubber gasket mechanical fastening seal; welding (argon arc welding, plasma beam welding) and vacuum nitrogen filling seal. From the perspective of sealing effect, the welding seal is — and the filling sealant is – poor. For sensors working in clean and dry indoor environment, glue sealed sensors can be selected, while for sensors working in humid and dusty environment, diaphragm hot sleeve seal or diaphragm welding seal, vacuum nitrogen filled sensors should be selected.
(3) In the environment with high corrosivity, such as moisture and acid, which may cause damage to the elastomer or short circuit of the sensor, the sensor with good corrosion resistance and good airtightness should be selected by spraying plastic or stainless steel cover on the outer surface.
(4) The influence of electromagnetic field on the output signal of sensor. In this case, the shielding of the sensor should be strictly checked to see if it has good anti electromagnetic ability.
(5) Flammable and explosive not only cause thorough damage to the sensor, but also pose a great threat to other equipment and personal safety. Therefore, the sensor working in flammable and explosive environment puts forward higher requirements for explosion-proof performance: in flammable and explosive environment, explosion-proof sensor must be selected. The sealing cover of this sensor should not only consider its tightness, but also consider the explosion-proof strength, as well as the waterproof, moisture-proof and explosion-proof properties of cable lead-out head.
When the truck scale is delivered from the factory, all parameters have been set and calibrated. When it arrives at the site, the first step is to adjust the bias load and zero reference, and the second step is to fine tune the measuring range. Generally, there is no need to reset and calibrate. Once the sensor, center plate, weighing display instrument and other components are replaced, they need to be reset and calibrated.