Vibrations and pulsations are dampened using liquid-filled gauges, which reduce their impact on the gauge dial pointer. They are generally employed in dynamic and harsh settings that may experience unexpected shocks or pressure spikes. They assist in ensuring that the gauge provides reliable readings over its rated duration. Because gauges do not collapse or need to be changed as frequently, they have a longer lifespan, which equals lower long-term costs.
Liquid-filled gauges are not affected by condensation since they are already filled with fluid and sealed and hence cannot be hidden by humidity and atmospheric air infiltration, as dry gauges may. The use of liquid-filled gauges dampens vibrations and pulsations, reducing their influence on the gauge dial pointer. They are commonly used in dynamic and severe environments where unanticipated shocks or pressure surges may occur. They aid in assuring that the gauge produces accurate readings for the duration of its rated life. Gauges have a longer life since they do not collapse or need to be changed regularly, resulting in cheaper long-term expenditures.
Because liquid-filled gauges have already been loaded with fluid and sealed, they are not influenced by condensation. They, therefore, cannot be disguised by humidity or ambient air intrusion as dry gauges may.
Glycerine-water mixes or silicone oils are the most often utilized filling solutions, depending on the working circumstances. The bulk of activities and ambient temperatures are suited for glycerine-water. Because of the low density of the liquid and the resulting low resistance on the pressure element, it makes sense to utilize it for low-pressure ranges. Silicone oil is mainly used when the glycerine filled pressure gauge is subjected to extremely high or shallow temperatures. Because the filling media collects extra water and swells in response to humidity and ambient temperature, the casing of the pressure gauge is not filled. The filling liquid preserves the pressure gauge’s mechanics by dampening pressure surges, jerks, and tremors. As a result, material degradation and breakdown are avoided.
Another important consideration for the user is the legibility of the current pressure. Even under strong vibration loads, the pointer’s mobility is restricted by the filling liquid. Without liquid dampening, the pointer might head back and forth in proportion to the frequency of the vibrations present in the application, rather than showing the exact applied pressure. In the event of resonance, a deflection angle of more than 180 degrees is possible.
Simply mentioned, filling a pressure gauge with liquid is primarily utilized as an affordable technique to stabilize the needle and clean the gauge’s internals during vibration applications. Glycerin and Silicone seem to be the most often utilized fill fluids. Glycerin is the “standard” in nearly all liquid filling applications, accounting for around 95% of all liquid filling applications. These fluids are utilized because they are more viscous and have a thicker consistency, which usually keeps the needle stable. Some gauges come empty, but they may be filled by simply pouring liquid into the tightly sealed gauge box through the refill port (typically at the top) and replacing the fill plug.
The Advantages of a Liquid-Filled Gauge
- It keeps the needle in place. The needle would jump violently if the gauge was not filled with liquid, making it challenging to identify precisely where the needle is pointed on the gauge.
- It’s a low-cost option that often comes pre-installed on a gauge.
- It extends the life of pressure gauges by softening and greasing the mechanical elements of the gauge.
A Liquid Filled Gauge’s Negatives
Industrial pressure gauges can face challenges such as fluid discoloration, leakage, and pressure build-up due to temperature fluctuations.
- Glycerin discoloration (darkening or yellowing) through time due to UV exposure or significant temperature fluctuations.
- Standard Glycerin is only effective at temperatures below 20 degrees Fahrenheit. It is not suitable for use in cold climates.
- Leakage is a possibility.
- Owing to the expansion and contraction of fluid due to temperature variations (typically modest, 1 PSI or so), pressure can build up in the casing, compromising the accuracy of the measurement and bringing the needle off of zero.
Silicone or a blend of Glycerin and purified water can be used instead of pure Glycerin if your application requires very low temperatures of 0 degrees or less. Both of these fluids can withstand temperatures as low as -40 degrees Fahrenheit.
Leakage is always a possibility with liquid-filled gauges, although the danger is minimal. The likelihood of leaking is determined by the gauge’s quality as well as the application. If leaking is your primary concern, choose a crimped bezel rather than a bayonet to reduce the risk. The crimped bezel keeps the gasket in place permanently, and it is less likely to come free in the service or due to human error. Again, because of advancements in manufacturing processes and standards, the chance of leakage is now relatively minimal.
