It is widely known that vibration, pulsation and pressure spikes are the most common causes of poor performance and failure in pressure gauges. It is also well known that in today’s extremely demanding world, instrumentation in the oil and gas and chemical industries, as well as in other applications in processing plants, has to work under these harsh conditions day in and day out.
Pumps, compressors and other rotating and mobile equipment are constantly subjected to strong vibrations which not only wear out the instrument but can also lead to inaccuracies since vibration makes it difficult to read the gauge and may move the pointer’s mechanism off zero. The use of liquid-filled, instead of dry, pressure gauges can help minimize these problems. With fewer problems and less downtime, liquid-filled pressure gauges are, in the long run, a more cost-effective solution.
In a liquid-filled pressure gauge, usually the case is filled with a non-aqueous fluid that effectively dampens vibration, pulsation and pressure spikes. The fluid also works as a lubricant and protects the delicate parts of the gauge. Liquid-filled gauges are sealed. They keep dirt and humidity out, preventing condensation and reducing visibility problems in high humidity situations. The sealing makes them an excellent choice for applications in corrosive environments, too.
Selection of the appropriate fluid for a liquid-filled gauge is crucial for ensuring good performance and a long life. WIKA has several options to choose from, and your decision should be based on the temperature range and media in which the gauge will be working. For example, temperatures too high may break down the fluid, and temperatures too low may solidify it, affecting, in both cases, the performance of the fluid and therefore that of the instrument.
Types of Liquid-Filled Gauges: Glycerin, Silicon and Halocarbon
Glycerin. Glycerin is the most commonly used liquid in liquid-filled gauges. Glycerin-filled gauges are a good value and provide good vibration dampening for applications at room temperature. These gauges work well in temperatures between -4°F and +140°F (-20°C and +60°C).
Silicone. Silicone and other comparable oils have lower viscosities even at very low temperatures; therefore, silicone-filled gauges are better for applications with extreme temperature variations, especially in colder climates and when icing may be expected. Their working temperature range extends from -40°F to +140°F (-40°C to +60°C).
Halocarbon. Halocarbon-filled gauges are better suited to applications that involve oxidizing agents such as chlorine, oxygen and hydrogen peroxide. They work within the same temperature range as glycerin-filled gauges, that is from -4°F to +140°F (-20°C and +60°C).
If your application includes electric accessories, insulating oils will give you better protection. Other fluids may be better suited to your application.
WIKA has designed some of the best liquid-filled pressure gauges you can find in today’s market. Contact WIKA and its team of support experts to discuss your needs. Let them help you find the liquid-filled gauge that better meets the requirements of your application.