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Complete Guide to Classification and Selection of Monocrystalline Silicon Pressure Transmitters
With the continuous advancement of industrial automation and increasing demands for measurement accuracy, safety, and reliability, monocrystalline silicon pressure transmitters have become core components in many critical process control systems. Based on monocrystalline silicon resonant or optimized piezoresistive technology, they provide 0.075% accuracy, extremely low drift, and strong environmental adaptability. They are widely used in petrochemical, power generation, pharmaceutical, metallurgical, and other industries. The Nexisense monocrystalline silicon series is a representative example of this technology, offering diversified classifications and flexible selection options to meet complex requirements ranging from micro differential pressure to high-temperature and high-pressure applications. This article systematically reviews the main classification methods and provides practical selection recommendations based on real operating conditions, helping engineers quickly choose the right product for the right application.
Main Classifications of Monocrystalline Silicon Pressure Transmitters
Monocrystalline silicon pressure transmitters can be classified from multiple dimensions, typically by measurement type, sensor capsule/structural design, and installation method. These classifications are not independent but intersect to form a comprehensive product spectrum.
Classification by Measurement Type
This is the most basic and commonly used classification, directly corresponding to application scenarios.
Monocrystalline Silicon Gauge Pressure Transmitters: Measure pressure relative to atmospheric pressure (Gauge Pressure). Commonly used for open tank level measurement and pipeline pressure monitoring. Nexisense gauge pressure models cover ranges from micro pressure to medium and high pressure, suitable for most conventional process control applications.
Monocrystalline Silicon Absolute Pressure Transmitters: Measure pressure relative to a vacuum reference (Absolute Pressure). Suitable for vacuum systems, gas density compensation, or applications with large atmospheric pressure fluctuations. Absolute pressure measurement eliminates atmospheric interference and provides higher accuracy.
Monocrystalline Silicon Differential Pressure Transmitters: Measure the pressure difference between two points (Differential Pressure). They are the mainstream choice for flow, level, and filter differential pressure measurement. Nexisense differential pressure series support high static pressure (up to 40 MPa) and micro differential pressure (as low as ±50 Pa), with dual overload protection to ensure safety.
Classification by Sensor Capsule / Structural Design
The structural design determines the transmitter’s isolation capability from the process medium and its applicable range.
Standard Monocrystalline Silicon Pressure Transmitters: The sensor directly contacts the medium or through a short impulse line. They feature a compact structure and fast response, suitable for clean and non-corrosive media.
Monocrystalline Silicon Remote Pressure Transmitters (Remote Type): Use capillary tubes filled with silicone oil. The external diaphragm directly senses pressure, which is transmitted via silicone oil to the internal monocrystalline silicon sensor. Remote design effectively isolates high-temperature, highly corrosive, or crystallizing media, protecting the electronics. Nexisense remote models are commonly used for high-temperature steam and viscous slurry applications.
Classification by Installation Method
The installation method affects on-site wiring, maintenance convenience, and measurement stability.
Monocrystalline Silicon Direct-Mount Pressure Transmitters: Directly connected to pipelines or equipment via threaded or flange connections. Commonly used for gauge and absolute pressure measurement. Easy to install and suitable for applications with sufficient space and non-extreme temperatures.
Monocrystalline Silicon Differential Pressure Transmitters: Typically installed with impulse lines or three-valve manifolds, mounted between pipelines or on vessel sides. Classic configuration for flow and differential level measurement.
Monocrystalline Silicon Flange-Mounted Pressure Transmitters: Include single-flange and double-flange designs. Single-flange types are commonly used for level measurement or single-side isolation; double-flange types are used for closed vessel level measurement (negative side connected to vapor phase for atmospheric compensation). Nexisense flange-mounted products offer various flange sizes (DN50, DN80, etc.) and diaphragm material options.
These classification combinations form complete product types, such as “monocrystalline silicon double-flange remote differential pressure transmitter” or “monocrystalline silicon direct-mount absolute pressure transmitter,” enabling precise matching to application requirements.
Key Selection Considerations for Monocrystalline Silicon Pressure Transmitters
Selection is not just about range; it requires comprehensive consideration of measurement type, process conditions, medium characteristics, and installation environment. The following sections describe typical application-based selection guidelines.
Pressure Measurement Applications
Gauge or absolute pressure models are preferred for conventional pressure monitoring.
Low to Medium Gauge Pressure (<10 MPa): Direct-mount or short impulse line standard models are economical and efficient.
Medium to High Gauge Pressure (>10 MPa): Reinforced flange or high static pressure models ensure overload capability.
Very Low Pressure (<500 Pa): Micro differential pressure transmitters are recommended to avoid instability from direct measurement.
Installation Method: Direct pipeline connection provides fast response; impulse line tapping is easier for maintenance.
Nexisense offers wide range coverage, with optional vibration damping or cooling accessories based on pipeline vibration and temperature conditions.
Differential Pressure and Level Measurement Applications
Level measurement is essentially a differential pressure application.
Open Vessels: Monocrystalline silicon gauge pressure transmitters, submersible transmitters, or single-flange level transmitters are sufficient. Single-flange diaphragms directly contact the medium and are easy to clean.
Closed Vessels: Double-flange level transmitters (positive side connected to liquid phase, negative side to vapor phase) automatically compensate for vapor pressure.
High Viscosity or Crystallizing Media: Single or double-flange remote transmitters prevent impulse line blockage. For severe crystallization, convex diaphragms or insertion types are recommended.
Micro Differential Level: High static pressure micro differential models provide extremely low static pressure error.
Flow Measurement Applications
Flow measurement typically uses differential pressure methods combined with primary elements such as orifice plates, Venturi tubes, or Annubar flow meters.
Standard Applications: Monocrystalline silicon differential pressure transmitters with primary elements output differential pressure signals, with flow calculated by DCS/PLC or secondary instruments.
Steam / Gas: Temperature and pressure compensation is required; select models with multivariable output or external compensation support.
High-Temperature Steam: Remote double-flange differential pressure transmitters isolate high temperatures.
Nexisense differential pressure series support the HART protocol, enabling local or remote parameter adjustment and compensation calculations.
Selection Recommendations for Special Operating Conditions
Ultra-High Temperature up to 600°C: Ultra-high-temperature remote transmitters (capillary + heat dissipation design) are mandatory to prevent electronic failure. Nexisense high-temperature remote models support this temperature range.
High Viscosity / Crystallizing Media: Flange-mounted remote or convex diaphragm types reduce blockage risk. Regular diaphragm cleaning is recommended.
Strongly Corrosive Media: Select diaphragm and wetted materials such as Hastelloy, tantalum, or 316L with PTFE coating. Flanges can be carbon steel, 304, or 316 based on cost considerations. Stainless steel housings are preferred.
Other Conditions: Explosion-proof applications require Ex d / Ex ia certification; vibration environments need damping brackets; humid environments require IP67 or higher protection.
Selection should also clarify range (with 1.5–2× margin), accuracy requirements, output signal (4–20 mA + HART), display/keypad needs, and mounting brackets.
FAQ
How to choose between gauge and absolute pressure transmitters? Gauge pressure is suitable for atmospheric reference measurements (e.g., open tank level), while absolute pressure is used for vacuum or applications requiring elimination of atmospheric influence (e.g., gas density calculation).
What is the main difference between remote and standard types? Remote types isolate high-temperature or corrosive media via capillary-filled silicone oil, protecting the transmitter body; standard types directly sense pressure with faster response but are unsuitable for extreme conditions.
How to choose between single-flange and double-flange level transmitters? Open vessels use single-flange or gauge pressure types; closed vessels must use double-flange transmitters to compensate vapor pressure.
Why are differential pressure transmitters recommended for micro pressure measurement? Direct micro pressure measurement (<500 Pa) is susceptible to fluctuations. Differential pressure transmitters provide higher stability and extremely low static pressure error with overload protection.
Is a differential pressure transmitter always required for flow measurement? Most throttling device-based flow measurements use differential pressure methods with monocrystalline silicon DP transmitters for high accuracy and stability; other principles may be used in special cases.
How to select for 600°C high-temperature applications? Choose dedicated ultra-high-temperature remote transmitters with sufficient capillary length (typically 5–15 m) to keep electronics away from heat sources.
What material requirements apply to corrosive media? Diaphragms and wetted parts should use corrosion-resistant alloys (e.g., Hastelloy C, tantalum); flanges can be carbon steel or 316L; stainless steel housings are preferred.
How to prevent blockage with crystallizing media? Prefer flange-mounted remote or convex diaphragm types; avoid long impulse lines; use steam tracing or periodic flushing if necessary.
What communication protocols do Nexisense monocrystalline silicon transmitters support? Standard support is 4–20 mA + HART, enabling configuration, diagnostics, and multivariable output; some models optionally support Modbus.
How much range margin should be reserved during selection? At least 1.5× under normal conditions; 2× or more for pulsating or overload-prone applications to ensure long-term accuracy and safety.
Conclusion
Through classification by measurement type (gauge/absolute/differential), structure (standard/remote), and installation method (direct/flange), monocrystalline silicon pressure transmitters form a diversified product range covering nearly all industrial requirements from conventional pressure measurement to extreme operating conditions. The Nexisense monocrystalline silicon series, based on high accuracy, strong overload capability, and intelligent compensation, provides flexible selection options for precise matching in pressure, level, and flow measurement, and reliable protection in high-temperature, corrosive, or crystallizing environments.
Selection is essentially a dialogue between process and instrumentation. Only by fully understanding medium characteristics, operating parameters, installation constraints, and balancing cost and maintenance convenience can the technical advantages of monocrystalline silicon transmitters be maximized. Choosing the right product not only improves measurement reliability but also supports process optimization and safety upgrades. If your project faces specific challenges, feel free to provide more details to jointly explore the optimal solution. Nexisense monocrystalline silicon pressure transmitters are committed to delivering reliable pressure measurement solutions for industrial automation.
