Highly accurate differential pressure transmitter with double sensor

Keller AG für Druckmesstechnik is launching the Series PRD-33 X. This impressive differential pressure transmitter features a double sensor for measuring the differential and line pressure independently, highly accurate measurements and a high overload resistance. Combining these benefits opens up new possibilities such as measuring the levels in liquefied gas tanks safely, accurately and at a reasonable price.

The PRD-33 X has two independent sensors and measures the line pressure as well as the differential pressure. The transmitter achieves its particularly high accuracy level of up to ±0.05% FS due to its calibration over the entire pressure and temperature range. The mathematical model calculated in this way corrects all repeatable errors. The high level of accuracy is therefore guaranteed as an error band within the overall compensated range. The floating assembly of the sensor unit provides the ideal protection from external forces during installation.

Application example: measuring the level in pressure tanks

Pressure tanks impose particular requirements on pressure transmitters. The closed systems require two measurements to determine the level: one for the tank pressure and one for the liquid pressure. Thanks to its two sensors, the PRD-33 X achieves this in one measurement process. All transmitter parts that come into contact with the medium are made from high-quality materials such as stainless steel AISI 316L, silicone, gold and silicon. The PRD-33 X is therefore perfectly suitable for use with (liquid) oxygen, argon, nitrogen, helium and carbon dioxide.

Very high overload resistance, even in the smallest pressure ranges

The requirements become even more extensive with cryogenic liquefied gases. Tanks that are smaller than three metres can have a differential pressure range of only 200 mbar – with a line pressure of up to 32 bar. With its line pressure compensation of 0...40 bar, the PRD-33 X can tackle this challenging combination with ease. When the tank is being filled or the valve is being used, the entire tank pressure can hit one side of the differential pressure transmitter. The PRD-33 X also copes brilliantly with the resulting 32 bar uneven overloading with its overload resistance of ±35 bar.

Simple configuration with free KELLER software

The PRD-33 X can be supplied with various electrical connections and has a digital RS485 interface. In addition to the process values of both pressure sensors, this provides further information such as pressure ranges, filter settings and the serial number. The software supplied with the PRD-33 X enables the transmitter to be configured and controlled and data to be saved easily. Using it in combination with a KELLER remote data transmission module or indicator further extends its range of functions and possible applications.