he primary reason for gauge failure is vibration. In traditional dry gauges, delicate links, pivots, and pinions are prone to damage from vibration, leading to inconsistent performance. In a liquid-filled gauge, the fluid fill effectively dampens system pulsation, making the gauge pointer easier to read.
Likewise, humidity and moisture pose problems for dry gauges. Condensation can make a gauge difficult to read or, in some cases, can cause failure due to icing. Liquid-filled gauges, though, are sealed to prevent internal condensation, and by keeping moisture out of the system, gauge movement is protected during icing conditions.
The choice of fill fluid is based on the application, but glycerin is typically used for room-temperature applications and silicone oil is commonly used for extreme temperature applications, especially when icing is a problem. An oil with insulating properties is ideal if the system has exposed electrical contacts.
Weldinspect, have seen glycerin filled gauges last a year and last for years in similar services (pulsating gas service). Dry gauges are specifically made for that service and also work, but you have not provided any indication of the operating conditions or experience with the gauge you are designing or replacing.
Nick: the gauges are already installed in a new industrial air conditioning system at the cold water lines. My inquiry is for general purposes comparing both systems. Thanks
I would stick with what you have installed and only consider a change if they fail. On a somewhat similar refrigeration system that is being built, the supplier uses non-filled gauges as a standard. Our Instrumentation group and the plant maintenance accepted dry pressure gauges due to the suppliers experience and cost savings.
