Low temperature resistance strain sensor elastomer is the basic design principle and all kinds of high temperature resistance strain sensor is the same.
Sensor precision, service life and output sensitivity sensor elastomer should generally control between 800 and 1500 m within the scope of m/m.
Sensor elastomer material, the requirements under the condition of low temperature, good elasticity, high tensile strength, high fatigue life and does not occur brittle fracture, and so on.
Elastomer material, generally at room temperature can choose mostly.
But at present, the pressure sensor stamping often choose stainless steel, aluminum, beryllium bronze and invar etc. , and such as sensor can choose extensometer beryllium bronze, the titanium alloy material.
Low temperature strain gauge is low temperature resistance strain type pressure sensor elastomer stamping key sensitive element, its performance affects the pressure sensor performance indicators.
Low temperature strain gauge is usually composed of basement, sensitive gate, adhesives, covering parts, etc.
All components material performance and basic performance directly affects the low temperature strain gauge.
Resistance strain type pressure sensor is composed of adhesive paste sensor elastomer, when under the action of external force, elastic body deformation occurs, elastic body deformation of the adhesive layer is passed on to the sensitive gate, cause sensitive grid material resistance changes, its resistance value changes with the elastomer by external force is a line between sex, measure the resistance value is elastomer by external forces.
Sensor stamping the practical work, the elastomer by external effect, at the same time also affected by environmental temperature, strain gauge caused by temperature change false output is often referred to as heat output, its value and the sensitive strain gauge grid material temperature coefficient of resistance, the sensitive coefficient, linear expansion coefficient of linear expansion coefficient, elastomer materials, and temperature and so on.
Used is usually required for sensor into slice heat output value is small, so as to guarantee the accuracy and stability.
Temperature adhesives and protective agent adhesives and protective agent for low temperature resistance strain sensor elastomer performance has a direct relationship.
Especially the adhesive, it of pressure sensor is particularly important.
A large number of trials show that: (
Low temperature strain gauge basal material, generally USES the polyimide film on glass fiber reinforced epoxy -
Phenolic resin film advisable, these materials under low temperature shrinkage of small, flexible, and adhesive bonding effect.
Adhesive strain gages are generally with thermosetting adhesives such as polyimide, modified epoxy -
After this kind of adhesive strips, after pressure heat curing and curing processing, rubber has a high bonding strength, good electrical insulating performance, creep, lag and zero drift small sensor, the sensor stability.
Under low temperature protection agent has an extremely important role in the stability of high pressure sensor.
Strain gauge pressure sensor applications, elastic body surface temperature from room temperature cooling medium injection and reduce gradually.
Elastomer cooling process, the micro amount of moisture in the air absorption elastomer surface, formation of frost.
When subjected to cyclical temperature sensor, strain gauge surface frost melting into water, make the strain gauge, adhesive absorb the moisture change and make the insulation resistance (
, bring up the sensor zero drift, creep and hysteresis, serious when the sensor failure.