Liquid-filled pressure gauges are essential for measuring pressure in harsh environments prone to vibration, pulsation, or extreme temperatures. The filling fluid dampens pointer oscillation, lubricates internal parts, and prevents condensation. The two most common fill fluids are silicone oil and glycerin, each with distinct advantages. Silicone Oil is the premium, versatile choice. It boasts an exceptionally wide operating temperature range (from -40°C to over 200°C), making it suitable for both freezing cold and high-heat applications. It is chemically inert, non-toxic, and highly stable, ensuring long service life without degrading or reacting with the gauge’s brass or stainless steel components. Its excellent damping characteristics effectively smooth out severe pulsation and vibration. Glycerin (Glycerine), a cost-effective alternative, performs well in standard industrial settings. It provides very good damping for vibration and pulsation at moderate temperatures (typically -20°C to 60°C). Its primary drawbacks are a narrower temperature range—it can become viscous in extreme cold and may ferment or degrade at high temperatures. While generally safe, it can be mildly corrosive to certain metals like brass over very long periods and is soluble in water, posing a potential contamination risk if the seal fails. Choosing the Right Fluid: Select silicone oil for applications involving extreme temperatures, high precision, chemical exposure, or when maximum longevity is required. Opt for glycerin for general-purpose use in stable, moderate environments where cost is a significant factor. Always consult the gauge manufacturer’s specifications to ensure compatibility with your process media and operating conditions.
