Resisting Water Freeze Damage with High Overpressure Ratings

August 06, 2019

Many outdoor applications have a need to monitor water pressure. Examples of these applications include crop irrigation, fire truck water tank level monitoring, engine water cooling, and road construction water spraying.

It is common for the aforementioned applications to be in severely cold climates, increasing the potential for water freeze during operation or overnight when equipment is idle. Water freezing often causes extreme high pressure, potentially up to several thousand psi depending on the system's rigidity. Such high pressure permanently damages most transducers.AXD High overpressure stop

Most standard pressure transducers are either strain gauge or piezoresistive sensing based. Strain gauge based sensors typically have limited overpressure ratings of 3X FS and piezoresistive MEMS sensing are often even lower with 2X FS proof pressure ratings. Said ratings are insufficient for protection against freezing water, especially in lower range pressure sensors from 15 PSIG to 500 PSIG. These sensors are not built to handle high overpressure and will be permanently damaged by water freezing. Avoiding water freeze damage with a standard pressure sensor often makes the system designer select a higher pressure range than desired, severely affecting the accuracy and usable analog output. For example, this would mean selecting a 5,000 PSIG range to resist ice freeze pressure instead of 100 PSIG to monitor water pump pressure.

Setra's Model AXD industrial pressure transducer has a high overpressure option to help resist damage from freezing ice conditions. It boasts low pressure ranges with high overpressure protection up to 10X FS. The Model AXD is a robust capacitance transducer that can resist ice freeze damage.