Introduction:
A diaphragm pressure gauge is a pressure measuring instrument specifically designed for corrosive, high-viscosity, easily crystallizing, or solid particle-containing media. It isolates the measured medium from the pressure gauge mechanism through a diaphragm, preventing the medium from corroding or clogging the instrument. It is widely used in harsh working conditions such as pharmaceuticals, food, chemicals, and new energy.
Core Structure and Working Principle
The core components include a diaphragm, an isolator, a filling fluid, a pressure gauge movement (such as a Bourdon tube or sensor), and a gauge head.
The diaphragm (often made of 316L stainless steel, Hastelloy, or PTFE) directly contacts the measured medium. The medium pressure causes the diaphragm to undergo minute deformation.
This deformation is transmitted through the filling fluid (such as silicone oil or glycerin) within the isolator to the pressure gauge movement. The movement converts the pressure signal into pointer deflection or an electrical signal (in digital displays), ultimately displaying the pressure value.
The diaphragm and isolator form a sealed chamber, completely isolating the medium from the movement and preventing corrosion and clogging problems at the source.
Core features and advantages
**Strong Corrosion Resistance and Adaptability:** The diaphragm is available in a variety of corrosion-resistant materials, suitable for corrosive media such as acids, alkalis, organic solvents, and salt solutions. The filling fluid exhibits high chemical stability and does not react with the media.
**Hygiene Compliance:** The sanitary model uses a 316L stainless steel diaphragm with a dead-angle-free structure, supporting in-line cleaning (WIP) and in-line sterilization (SIP), complying with GMP and FDA standards, and suitable for aseptic environments.
**Stable and Reliable Measurement:** The filling fluid buffers media impact and pulsation, reducing the impact of pressure fluctuations on measurements. The high-strength diaphragm can withstand the abrasion of crystalline media or solid particles.
**Suitable for Complex Operating Conditions:** With a wide measurement range (typically -0.1~40MPa) and a wide temperature tolerance range (-40℃~200℃), it can be used for pressure measurement of high-viscosity and easily solidifying media, avoiding instrument clogging.
Main types and applicable scenarios
Flanged Diaphragm Pressure Gauges: The diaphragm connects to the equipment via a flange, ensuring a strong seal. Suitable for pressure measurement in containers, reaction vessels, and other equipment (e.g., pharmaceutical mixing tanks, chemical reaction vessels).
Threaded Diaphragm Pressure Gauges: Easy to install, suitable for pressure monitoring in pipelines and small equipment (e.g., pipelines in food and beverage production lines, lithium battery electrolyte delivery pipes).
Sanitary Diaphragm Pressure Gauges: Use quick-connect flanges, with a polished surface (Ra≤0.8μm), eliminating sanitary dead corners. Suitable for aseptic production environments such as pharmaceuticals, dairy products, and vaccines.
Digital Diaphragm Pressure Gauges: Equipped with a digital display and signal output (4-20mA), compatible with PLC and DCS systems. Suitable for closed-loop pressure control in automated production lines (e.g., chemical batching processes, new energy equipment monitoring).
Explosion-proof Diaphragm Pressure Gauges: Ex explosion-proof certified, suitable for flammable and explosive media environments (e.g., solvent storage tanks, oil and gas processing equipment), preventing hazards caused by sparks.
Typical application industries
Pharmaceutical/Vaccine Industry: Pressure monitoring of aseptic mixing tanks and fermenters, conforming to GMP standards, preventing media contamination and instrument corrosion.
Chemical Industry: Pressure measurement of corrosive media storage tanks and reactors, suitable for harsh media such as acids, alkalis, salt solutions, and organic solvents.
Food/Dairy Industry: Pressure monitoring of high-temperature sterilization autoclaves and yogurt fermentation tanks, hygienic, non-toxic, and residue-free.
New Energy Industry: Pressure detection of lithium battery cathode reactors and high-pressure hydrogen storage tanks, resistant to electrolytes, hydrogen, and other special media.
Environmental Protection Industry: Pressure measurement of wastewater treatment equipment and desulfurization towers, suitable for corrosive media such as chlorine-containing wastewater and desulfurization slurry.
