Liquid-filled gauges are generally preferred over dry gauges for two reasons: performance and ROI. Liquid-filled gauges are filled with a liquid, usually glycerin or silicone oil and are designed to perform optimally in less-than-ideal conditions. While WIKA’s liquid-filled gauges are engineered to function in difficult environments, they’re also more economical from a long-term perspective: High heat, pulsation, or vibration lead to instrument breakdown, but WIKA’s liquid-filled gauges stand up to these harsh conditions.
Liquid Filled vs. Traditional Gauges
The 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.