The wetted materials of a pressure sensor must maintain chemical compatibility with the process media throughout the operational lifecycle. Incompatible materials can lead to corrosion, contamination, or sensor degradation that manifests as measurement drift or complete failure. Specialized applications like high-purity pharmaceutical processes or aggressive chemical media demand particular attention to material specifications.
For high pressure transducer applications, material selection becomes even more critical as mechanical strength requirements must be balanced with chemical resistance. Common wetted materials include 316L stainless steel for general industrial use, Hastelloy for corrosive environments, and titanium for specialized applications. The sealing materials (elastomers or polymers) must also be evaluated for temperature and chemical compatibility.
Practical Tip: When dealing with unknown media compatibility, conduct accelerated aging tests with actual process fluids or consult material compatibility charts from sensor manufacturers. The waterproof pressure sensor series demonstrates how specialized material treatments can enhance performance in wet environments.
Managing Hydraulic Shock and Pulsation
Hydraulic shock (water hammer) represents a frequent cause of premature pressure sensor failure in fluid systems. These pressure spikes can momentarily exceed the sensor's rated capacity by several times normal operating pressure, potentially damaging the sensing diaphragm or electronics. Systems with quick-closing valves, rapid pump starts/stops, or slug flow conditions are particularly susceptible.
Sensor Protection Strategies: Pressure snubbers restrict fluid flow to dampen spikes, while pulsation dampeners absorb energy through gas-filled chambers. Capillary extensions create a buffer zone between the process and sensor. Some high pressure transducer models incorporate reinforced diaphragms specifically for shock-prone environments.
System Design Considerations: Gradual valve operation, surge tanks, and proper pipe sizing can mitigate shock at the system level. When retrofitting existing systems, evaluate the sensor's resistance to both mechanical shock (vibration) and hydraulic shock separately, as specifications may differ.
Pressure Reference Fundamentals
The reference pressure type fundamentally determines the sensor's measurement capability and appropriate applications. Gauge pressure sensors measure relative to atmospheric pressure and are most common in industrial processes. Absolute pressure sensors reference a perfect vacuum, essential for applications like altitude measurement or vacuum systems.
| Reference Type | Key Characteristics | Typical Applications |
|---|---|---|
| Gauge | Measures relative to atmospheric pressure, vented to ambient | Industrial processes, HVAC, hydraulics |
| Absolute | References perfect vacuum, sealed internal chamber | Barometric pressure, vacuum systems, altitude |
| Differential | Measures difference between two process points | Filter monitoring, flow measurement, level |
| Sealed Gauge | References fixed pressure (not atmospheric) | Subsea applications, deep well monitoring |
Accuracy Interpretation and Implications
Pressure sensor accuracy specifications require careful interpretation as manufacturers may use different calculation methods (BFSL, RSS, TEB) and test conditions. A stated 0.25% accuracy could represent fundamentally different performance depending on whether it includes zero and span errors, temperature effects, and long-term stability.
Critical Accuracy Components: Beyond the basic percentage specification, examine whether the accuracy statement includes hysteresis, non-linearity, repeatability, and thermal errors. For temperature-variable environments, request accuracy specifications across your expected operating range rather than just room temperature performance.
Field Interchangeability Requirements
Maintaining consistent system performance during sensor replacement demands attention to interchangeability specifications. Sensors with tight zero and span tolerances allow direct replacement without recalibration, while others may require field adjustment to maintain original system accuracy. This becomes particularly important in distributed systems with multiple measurement points.
The waterproof pressure sensor series exemplifies designs that maintain consistent performance specifications across production batches, facilitating easier field replacement. When evaluating interchangeability, consider both the initial calibration tolerance and long-term drift characteristics that affect maintenance intervals.
Specialized manufacturers like Sino-Inst continue developing advanced pressure measurement solutions including robust high pressure transducer options for demanding industrial applications, contributing to more reliable and accurate process measurements