The installation environment of a pressure sensor has many effects on its measurement accuracy, mainly in the following aspects:
Temperature
Thermal expansion and contraction effect
When the ambient temperature changes, the pressure sensor's housing, internal elastic elements, and measurement circuitry will all undergo changes in size and physical properties due to thermal expansion and contraction.
For example, in high-temperature environments, the stiffness of elastic elements may decrease, leading to increased deformation under the same pressure. This, in turn, alters the electrical signal output by the sensor, causing measurement errors. Generally, for ordinary pressure sensors, the measurement error may increase by 0.1% to 0.3% for every 10°C change in temperature.
Zero Drift
When exposed to an environment with unstable temperature for an extended period of time, the zero point of the pressure sensor will drift, meaning that when the pressure is zero, the sensor's output value will no longer be zero.
This is because temperature changes affect the performance parameters of the electronic components inside the sensor, such as resistance and capacitance, thereby altering the sensor's initial output state. For example, in some industrial settings, if the temperature difference between day and night is significant, the zero point of a pressure sensor may drift by several millivolts or even tens of millivolts within a single day, severely impacting measurement accuracy.
Temperature gradient effect
If there is a temperature gradient in the installation environment, that is, the temperature is not uniform in different locations, it will cause thermal stress to be generated inside the pressure sensor.
This thermal stress can cause slight deformations in the sensor's structure, altering its sensitivity and linearity and leading to measurement inaccuracies. For example, pressure sensors installed near large heating furnaces may experience uneven temperature distribution due to the furnace's uneven heat dissipation, reducing measurement accuracy.
Vibration
Mechanical vibration interference
Pressure sensors installed on equipment or pipelines subject to significant vibration can be affected by the vibration, causing additional vibration deformation in the elastic elements inside the sensor.
This additional deformation, superimposed on the pressure-induced deformation, causes fluctuations in the sensor's output signal, affecting measurement accuracy. For example, pressure sensors installed near equipment such as compressors and pumps may experience measurement errors as high as 5% or even higher if effective vibration damping measures are not taken.
Long-term vibration damage
Continuous vibration can also cause problems such as loose internal connections of the pressure sensor, detached solder joints, and component damage.
For example, some pressure sensors manufactured using microelectromechanical systems (MEMS) technology are prone to fatigue damage under long-term vibration, which can degrade the sensor's performance or even cause it to fail, seriously affecting measurement accuracy and reliability.
Electromagnetic interference
External electromagnetic field influence
When a pressure sensor is installed near a strong electromagnetic field source, such as a large motor, transformer, or welding machine, the external electromagnetic field will induce an electromotive force on the sensor's signal line.
This induced electromotive force is superimposed on the normal output signal of the sensor, causing signal distortion and leading to measurement deviations. For example, in power substations, if a pressure sensor is installed close to high-voltage equipment, electromagnetic interference may increase the sensor's measurement error by 1% to 3%.
electrostatic interference
In dry environments, static electricity can easily accumulate. If a pressure sensor is installed in such an environment without proper grounding, static charge may build up on the sensor surface.
When static electricity accumulates to a certain level, it will discharge through the sensor's internal circuitry, interfering with the sensor's normal operation and causing abnormal measurement data. For example, pressure sensors installed on some chemical powder conveying pipelines are prone to static electricity generation due to powder friction. If the grounding is poor, measurement errors may occur frequently.
Regarding humidity and corrosive gases
Humidity
High humidity environments can reduce the insulation performance of pressure sensors, leading to leakage in the internal circuitry of the sensor.
This can not only affect the measurement accuracy of the sensor, but may also damage its electronic components. For example, in some damp underground mines, if pressure sensors are not properly protected, humidity may reduce the insulation resistance of the sensor, increasing measurement errors.
Corrosive gas erosion
When pressure sensors are exposed to environments containing corrosive gases, such as sulfur dioxide, hydrogen sulfide, and chlorine, these gases can corrode the sensor's housing, elastic elements, and internal circuitry.
Corrosion can alter the structure and performance of sensors, reducing their measurement accuracy and lifespan. For example, in chemical production workshops, if pressure sensors are not effectively protected against corrosion, prolonged exposure to corrosive gases can reduce their sensitivity by more than 20%, or even cause them to fail completely.
Installation location and fluid characteristics
Improper installation location
If a pressure sensor is installed near local resistance elements such as bends or valves in a pipeline, the flow state of the fluid will change drastically, generating eddies and pressure fluctuations.
This unstable pressure can cause the pressure values measured by the sensor to be inaccurate and fail to accurately reflect the actual pressure inside the pipeline. For example, installing a pressure sensor at a bend in a fluid delivery pipeline can result in a measurement error of 3% to 5%.
Influence of fluid properties
When measuring the pressure of fluids containing impurities, bubbles, or high viscosity, these fluid characteristics can also affect the measurement accuracy of pressure sensors.
Impurities can clog the sensor's pressure interface, preventing the sensor from accurately measuring pressure; the presence of air bubbles can alter the density and elasticity of the fluid, leading to deviations in pressure measurements; and highly viscous fluids can increase the stress on the sensor's elastic elements, causing the measurement result to be too high. For example, when measuring the pressure of oil containing a large number of air bubbles, the measurement error can be as high as approximately 10%.
