Innovative Applications and Technical Advantages of Differential Pressure Transmitters

I. Core Application Scenarios

01 Flow Measurement (Most Typical Application)

• Principle: By measuring the differential pressure generated when fluid flows through a throttling device (such as an orifice plate or Venturi tube), the flow rate is calculated in combination with Bernoulli's equation.
• Scenarios:
  
  
  ✔ Petrochemical industry: Feed flow measurement of distillation towers, metering of natural gas pipeline transportation
  
  
  ✔ Water supply and drainage: Inlet flow monitoring of sewage treatment plants, leakage detection of urban water supply networks
  

02 Liquid Level and Material Level Monitoring

• Open containers: Utilizing the linear relationship between liquid height and bottom pressure, the differential pressure transmitter measures the pressure difference between the bottom pressure and atmospheric pressure to convert it into liquid level height.
• Sealed containers: Simultaneously connecting the bottom pressure (positive pressure port) and top air pressure (negative pressure port) of the container to eliminate the interference of air pressure fluctuations on liquid level measurement (e.g., liquid level control of reaction kettles)

03 Pressure Difference and Resistance Monitoring

• Pipeline resistance analysis: Measuring the differential pressure across filters and heat exchangers to determine whether the equipment is clogged (e.g., differential pressure alarm for filters in central air-conditioning water systems).
• Gas flow control: In air volume regulation systems, real-time adjustment of fan speed by measuring the differential pressure across orifice plates (e.g., air volume control in boiler combustion systems)

04 Industrial Process Control

• Chemical reaction control: Monitoring pressure differences at different points in the reactor to determine the uniformity of material mixing or changes in catalyst bed resistance.
• Metallurgical industry: Differential pressure monitoring of the mold level in continuous casting machines to ensure the stability of molten steel level.

II. Technical Advantages and Industrial Value

01 High Precision and Stability

• Measurement accuracy: The accuracy of mainstream products reaches ±0.075% FS, and some high-end models (e.g., intelligent ones) can achieve ±0.05% FS through digital compensation, meeting the requirements of trade settlement grades.
• Environmental adaptability:
  • Vibration resistance: Built-in dampers or electronic filtering algorithms ensure stability even in environments with vibration ≤50 m/s².
  • Temperature compensation: Dual-sensor design (pressure + temperature) automatically corrects temperature drift errors (e.g., error ＜ ±0.2% within the operating range of -40℃ ~ 85℃)

02 Functional Integration and Intelligence

• Multi-parameter measurement: Some models can output differential pressure, static pressure, and temperature signals simultaneously (e.g., Rosemount 3051 series), reducing the number of instruments and installation costs.
• Digital communication and diagnosis: Supports HART and 4-20mA + digital signals, enabling real-time upload of equipment status (e.g., diaphragm damage warning, zero drift alarm) for convenient remote operation and maintenance.

03 Adaptability to Complex Working Conditions

• High differential pressure scenarios: With a pressure resistance rating of up to 42 MPa, it is suitable for high-pressure natural gas pipelines.
• High and low temperature environments: Temperature resistance ranges from -196℃ (liquid nitrogen storage tanks) to +400℃ (steam pipelines)

04 Cost and Maintenance Advantages

• Low installation cost: Compared with multiple single-pressure instruments, a single differential pressure transmitter can realize differential measurement, reducing pipeline openings and valve configurations.
• Convenient maintenance: Intelligent products support on-line calibration without disassembly; anti-clogging design of pressure guiding pipes (e.g., self-purging function) reduces cleaning frequency.

III. Differentiated Advantages Over Other Pressure Instruments

• Compared with single-pressure instruments: Differential pressure transmitters can directly output differential signals, avoiding error superposition of two instruments (e.g., when measuring pipeline resistance, the error of single instruments is ±0.5%, while that of differential pressure transmitters is ±0.1%).
• Compared with flowmeters: In scenarios with large pipe diameters (DN ＞ 1000 mm), the cost of a differential pressure transmitter + throttling device is only 1/3 to 1/2 of that of an electromagnetic flowmeter, and maintenance is simpler.
  

Summary