Summertime and the Livin’ is Easy – with Pressure Sensors

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll discuss pressure sensors for pool filters.

Summertime and the Livin’ is Easy – with Pressure Sensors

Well, it’s officially summer and one of the “livin’ is easy” moments occurs when you get to spend some time in a pool. While the pool is refreshing, there is a maintenance side and work involved in keeping it clean. The pool filter maintenance indicator is a pressure sensor that typically has a 0-60 PSI gage readout.

The pressure sensor measures a gage reading, the pressure in the filter, since it does not have to record flow. A normal operating pressure is observed when the pool filter is clean and running at a specified rpm. When the pressure in the filter increases by a few psi, it’s time for backwashing.

Since the gauge requires an operator to determine if it is time for backwashing, the sensors are simple mechanical sensors. For other filter applications that require an electronic signal, a MEMS pressure sensor usually is preferred to other sensor technology options for cost, ease of interface and reliability reasons. This is the case for commercial air filters and healthcare applications such as high-efficiency particulate air (HEPA) ultra-low penetration air (ULPA) filtration systems or ventilation units.

HEPA and ULPA filters are typically operated under pressure of approximately 203 mm (8in.) of water column. For these types of applications flow is typically measured, so a differential rather than static pressure measurement is made to determine when it is time to replace the filter. While measuring air simplifies the mechanical interface and avoids problems with liquids, the small ∆P measurement requires a specially designed pressure range to produce an easily managed output. In any case, this is an application easily handled by MEMS pressure sensors.


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-Dan DeFalco, Marketing Manager, All Sensors Corporation (