Highly Stable Absolute Pressure Transmitter IP65 Gauge Pressure Transmitter 24 V DC

The absolute pressure transmitter is a type of instrument that measures the pressure of the medium with absolute vacuum (zero pressure) as the reference zero point, and it is not affected by the external atmospheric pressure environment, thus having strong stability.

• Measurement independent of atmospheric pressure: Its readings do not change with local altitude or weather variations. This is its most fundamental advantage.
• Constant zero point: As the reference vacuum is permanent and stable, its zero point theoretically does not drift (in practice, it is affected by manufacturing processes and temperature, but remains very stable).
• Suitable for vacuum measurement: It is the most direct and accurate type of instrument for measuring vacuum (pressure lower than atmospheric pressure) because it can accurately read pressure values starting from zero.

1. Vacuum processes and systems (core application):
   • Semiconductor manufacturing: In CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), etching and other process chambers, precise measurement and control of high, medium and low vacuum levels are crucial for the success of the process.
   • Vacuum coating, vacuum heat treatment: Precise control of the absolute pressure inside the furnace.
   • Freeze dryer: Monitoring the absolute vacuum level in the drying chamber to control the sublimation process.
   • Vacuum pump performance testing: Measuring the ultimate vacuum and pumping speed of the pump.
2. Processes involving phase change or boiling point control:
   • Distillation column pressure control: The top pressure of the column (especially in vacuum distillation) must use an absolute pressure transmitter because the boiling point of the material is directly related to the absolute pressure (according to the Antoine equation). Using a gauge pressure transmitter would cause the boiling point to change due to fluctuations in atmospheric pressure, affecting product purity and separation efficiency.
   • Evaporators, crystallizers: Similarly, controlling the absolute pressure to precisely control the evaporation temperature.
3. Meteorology and scientific research:
   • Atmospheric pressure measurement: The barometer in a weather station is essentially an absolute pressure transmitter, measuring the local absolute atmospheric pressure.
   • Laboratory research: Any experimental setup requiring an accurate pressure reference.
4. Height and depth measurement:
   • Aircraft altimeter: Its principle is to measure the absolute pressure of the external atmosphere and convert it to altitude based on the pressure-altitude formula.
   • Dive depth gauge: Essentially, it measures the absolute pressure of water (hydrostatic pressure + atmospheric pressure) to calculate depth.
5. Compressor outlet pressure (optional):
   • When precise calculation of gas density, mass flow rate or performance evaluation is required, using an absolute pressure transmitter is more accurate than a gauge pressure transmitter because it eliminates the influence of atmospheric pressure changes.

The absolute pressure transmitter is the "absolute ruler" in the field of pressure measurement, providing reliable and stable measurement solutions for processes that require a vacuum reference or precise physical pressure values.