SUPPLY HOUSE TIMES – NOVEMBER 2016
Liquid-filled pressure gauges are the economical instrument traditionally used to measure pressure in applications with severe vibration and pulsation.
The liquid-filled case reduces pointer flutter, allowing the pressure to be accurately read. These gauges have limitations reducing their effectiveness in many applications, but for years no cost effective alternative was available. Operators were forced to accept a compromise in performance in order to monitor their system pressure.
Commercial greenhouses provide an environment that is harsh for liquid-filled pressure gauges. Pumps used for facilitating the movement of water through the greenhouse vibrate. In order to accurately monitor the pressure of the pump, the gauge pointer needs to be dampened to be readable. These gauges also are exposed to the UV of the sun. The result is the fluid in the gauge discolors, making it difficult to determine the pressure of the system. This problem is amplified when the gauge pointer is operated at the ’12 o’clock’ position where the dial increments are partially obscured by the meniscus of the fill.
When some greenhouse operators approached Winters Instruments with their issue, they were convinced they had one of two options. They could use a dry gauge and get a less accurate reading of the pressure in their system or they could continue using glycerin-filled gauges, which would require frequent replacement. Winters was able to resolve their issue by recommending they switch to a StabiliZR™ pressure gauge.
StabiliZR™ pressure gauges are dry gauges that come with a StabiliZR™-dampened movement that eliminates pointer flutter caused by vibration and pulsation. The pointer shaft of a StabiliZR™ gauge is extended through the back of the movement with a small flat paddle affixed to the end of the shaft, covering the paddle. This creates enough resistance to dampen the pointer and movement. Because the entire case isn’t filled, there is no risk of liquid discolouration and no meniscus impairing the reading of pressure. In addition, because the silicone is hermetically sealed in a cap, there’s no risk of fluid leakage.
Initially, the greenhouse operators were hesitant to switch to StabiliZR™ as liquid filling was ingrained in the industry as the sole method for dampening pressure gauge vibration. However, Winters was able to convince them by presenting a visual demonstration of the StabiliZR™ gauge operating in a high-vibration setting next to a glycerin-filled gauge. The operators were also shown independent third-party testing that shows StabiliZR™ gauges are as accurate as glycerin-filled gauges when exposed to severe cycling.
After reviewing the data, the operators were willing to test a StabiliZR™ gauge in one of their greenhouses. After years of settling for compromised performance from liquid-filled gauges, the StabiliZR™ gauge impressed them enough that they decided to convert all their liquid-filled gauges to StabiliZR™ models.