A weight sensor is actually a device that converts a mass signal into a measurable electrical output. With the sensor to consider the actual working environment of the sensor, this is very important to the correct selection of sensors, it is related to the sensor can work normally and its safety and service life, and even the reliability and security of the whole weighing instrument.
一、 The impact of the environment on the sensor mainly has the following aspects:
(1) The high temperature environment causes problems such as melting of coating materials, welding joints and structural changes of internal stresses of elastomer to the sensor. High temperature sensor is often used for working in high temperature environment; In addition, must be added heat insulation, water cooling or air cooling devices.
(2) Dust, humidity on the sensor caused by short circuit. In this environment, the sensor with high airtight should be selected. The way of sealing is different for different sensors, and the sealing property is very different.
The common seal is sealant filling or coating; Rubber pad mechanical fastening seal; Welding (argon arc welding, ion beam welding) and vacuum-filled nitrogen seal.
From the sealing effect, welding sealing is the best, filling coated sealant is the amount of difference. For the indoor clean and dry environment of the sensor, you can choose the sensor coated with glue seal, and for some sensors in the humid and dusty environment, should choose the diaphragm hot sleeve seal or diaphragm welding seal, vacuum filled nitrogen sensor.
(3) in the corrosive environment, such as humidity, acid on the sensor caused by elastomer damage or short circuit, should choose the outer surface of the plastic sprayed or stainless steel cover, corrosion resistance and sealing good sensor.
(5) Inflammable and explosive not only cause thorough damage to the sensor, but also pose a great threat to other equipment and personal safety. Work in inflammable, explosive environment, therefore, the sensor puts forward higher demands on explosion-proof performance: in the inflammable, explosive environment must choose explosion-proof sensor, the sensor of the seal cover should not only consider its impermeability, also considering the strength of explosion-proof, cap and cable waterproof, moisture-proof, explosion-proof, etc.
二、 The number of sensors and range selection
The choice of the number of sensors is based on the use of electronic weighing instrument, the number of points needed to support the balance body (support points should be determined according to the principle of the balance body geometric center of gravity and the actual center of gravity coincidence). In general, the scale body has a few support points on the selection of several sensors, but for some special scale body such as electronic hook scale can only use a sensor, some electronic mechanical scale should be based on the actual situation to determine the number of sensors.
The range selection of column type weighing sensor can be determined according to the comprehensive evaluation of factors such as the large weight value of the scale, the number of selected sensors, the weight of the scale body, the possible large offset load and the dynamic load. In general, the closer the range of the sensor is to the load assigned to each sensor, the more accurate the weighing will be. But in the actual use, due to the load added to the sensor in addition to the object, there is also a weight, tare weight, partial load and vibration impact load, so the selection of sensor range, to consider many aspects of the factor, to ensure the safety and life of the sensor.