Wet/Wet Differential Pressure Sensor Ideal for Monitoring Cleanliness of Filtration Systems

September 28, 2007 (PRLEAP.COM) Technology News
American Sensor Technologies, a New Jersey-based manufacturer of state-of-the-art, MEMS-based pressure sensing products, offers a wet/wet differential pressure sensor ideal for monitoring the cleanliness of filters in either liquid or gas applications.

When installed within a water filtration system, the Model 5000 Wet/Wet Differential Pressure Sensor can detect the difference between the upstream pressure, that drives the water through the filter, and the downstream pressure, that leads the filtered water through the system, to notify the system when the filter is clogged.

For example, in a 100 PSI pump using a filter to purify water for drinking, if the pressure in the downstream side of the system drops to 80 PSI, the filter should be changed. With a 24VDC supply powering the Model 5000 wet/wet different pressure sensor and a selected 4-20mA output signal, the sensor can be calibrated with a 100 PSI line pressure and a 20 PSI differential pressure.

When the water filtration system is operating with a clean filter, the output signal will be 4mA. As the pressure decreases on the downstream, the output signal will increase. Once the downstream pressure decreases to 80 PSI, the sensorís output signal will reach the full scale of 20mA. When connected to a controller, the operator understands when to replace the filter.

Hereís How the System Works (refer to attached photo)

1. For filtration applications, the upstream side (A) is positioned before the filter (B). The upstream pressure (commonly referred to as the line pressure or influent pressure) drives the media through the filter. A line is installed to the pressure sensor before the filter as well as connected to the high side of the sensor.

2. The filter, then, removes contaminants from the media as it flows through and enters the downstream side of the system.

3. Next, the downstream pressure or effluent pressure leads the filtered media through the system. The downsteam side (C) is located after the filter. A line is installed on the low side of the pressure sensor to monitor the differential.

4. When the filter is free of contaminants, the system will measure 0 PSI in pressure. As the filter becomes clogged, the pressure on the downstream side reduces, which creates a greater differential between the High and Low sides. By using a differential pressure sensor, the unit will offer a linear output signal based on the differential pressure.

About the Model 5000 Wet/Wet Differential Pressure Sensors

In addition to featuring highly accurate output of differential pressure, the Model 5000 is constructed of 316L stainless steel wetted materials that resist hydrogen embrittlement to ensure the highest reliability in a variety of media. This design also provides excellent overrange and burst protection (5x rated line pressure or 2,000 PSI, whichever is less) ratings for system safety in the most extreme conditions. Featuring ASTís Krystal Bondô Technology, the Model 5000 does not contain internal O-rings or fluid-filled cavities, eliminating the chance of outside media permeation or system contamination from silicone oil.

Voltage and current outputs are available over a wide operating temperature range of -40 to 85̊C (-40 to 185̊F). Accuracy specifications are < 0.3% BFSL, including non-linearity, hysteresis, and non-repeatability. For more information about the hydrogen compatible Model 5000 Wet/Wet Differential Pressure Sensors, go to American Sensor Technologies web site at: http://www.astsensors.com/model5000.html.

About AST
AST manufactures state-of-the-art, MEMS-based pressure sensing products that offer the best price-performance ratio in the industry. Common applications of AST sensor products are in industrial OEM, hydraulic systems, fuel cells, medical gases, HVAC/R, refrigeration (ammonia, Freon, CO2), oil & gas exploration and production, and off-road vehicles. By combining exotic metals and ASTís exclusive, proprietary Krystal Bondô Technology (an advanced process in which inorganic materials are molecularly diffused onto a metallic surface in the presence of certain gases), AST can produce high-performance strain gauge pressure sensors that support the specialized needs of key niche markets. Many AST products are UL listed as intrinsically safe and certified for explosion-proof required environments. Some of the worldís most highly respected industrial Fortune 500 corporations have tested and now use AST products in a wide range of critical and harsh environments. For more information on AST products and technology, go to ASTís website at www.astsensors.com.