Company : KELLER AG für Druckmesstechnik

Category : Test and Measurement

Key Products : Isolated pressure transducers, Piezo resistive pressure sensors, Isolated pressure transmitters

KELLER AG für Druckmesstechnik, Global headquarters located in Switzerland, is Europe’s leading manufacturer of isolated pressure transducers and transmitters. The company overall has a workforce of around 400 employees, was founded in 1974 by Hannes W. Keller, a graduate in physics and the inventor of the integrated silicon measuring cell. The entire value creation from production of the individual parts and calibration of the sensor through to the final inspection of the finished products takes place at the headquarters in Winterthur. All KELLER AG products are therefore “Made in Switzerland”.

KELLER AG piezo-resistive pressure sensors have impressively high precision and pressure ranges from 5 mbar to 2000 bar. In addition to more than 500 standard products, the company also develops and produces numerous customised solutions. Using state-of-the-art, automated manufacturing processes, large runs of industrial OEM transducers as well as special design versions in very small quantities are produced in more than 35 highly-specialised machining islands, resulting in more than one million pressure transducers and transmitters per year.

The KELLER AG offers wide range of products that includes digital manometers, level probes, data loggers, remote transmission units & pressure calibrators and Digital display equipment. The application areas for pressure transducers are just as broad as the product range. KELLER special sensors, such as modular pressure catheters and other miniature transducers, are especially popular among researchers.

Pressure Transducers

The piezo-resistive pressure transducers Series M5 are ideal, thanks to the M5 fine thread, for taking measurements at close proximity in places where access is a problem and in very thin pipes exactly the kinds of conditions associated with engine test benches. The front-flush design prevents gas bubbles interfering with fluid measurements and supports measurements up to 200 °C without a cooling adapter. The extreme dynamic range of 0-50 kHz makes it possible to record very fast pulsations just as reliably as those associated with static pressure values. A vibration-resistant Teflon FEP cable (IP67) ensures the 80 mV output signal is routed securely out of the hot environment and then onwards for processing.

The Series M5 sensor incorporates a stable silicon sensor which is backside-soldered directly to a supporting element designed for excellent fluid dynamics. This construction eliminates the disadvantages of sealants, adhesives, separating membranes or capillary tubes in high temperature environments.

Applications involve in Test Benches, Leakage, Wind Tunnels, Aviation, Compressors or Explosion Waves

High-Resolution Manometer

The LEO 5 combines the notable features of Keller’s successful LEO-Record and LEX 1 digital pressure gauges, featuring an IP66-rated stainless steel enclosure. This robust housing combines contemporary microcontroller-based electronics and capacitive-touch controls, operated through the environmentally-sealed safety glass front panel. The large backlit LCD display ensures readability in any lighting conditions. Two selectable measurement modes, standard and peak, are included to ensure maximum versatility. In standard mode, high-resolution pressure measurements are taken twice per second. When operating in peak mode, sampling frequency increases to 5 kHz with 16 bit resolution. The LEO 5 interfaces with a PC via USB connectivity, allowing access to active measurements and recorded data including pressure, peak pressure, temperature, and measurement interval.

Pressure Level Transmitter

The 36 Xi W series is built on the latest-generation microcontroller platform, which KELLER has developed to meet extremely high precision requirements and increase compatibility with a wide variety of interfaces. Along with pressure (level) information, digital interfaces also transmit other water parameters such as temperature and conductivity.

The 36 Xi W series is based on the proven KELLER 36 X W series using the high-quality 10 L-series pressure transducer. All series X pressure level transmitters feature an RS485 interface, which provide pressure and temperature standard, while versions requiring higher accurately, temperature or conductivity sensor are available options. Multi-parameter probes fitted with pressure, temperature and conductivity sensors (CTD – conductivity, temperature, depth), are approximately 90 mm longer.

  • Pressure sensor: resolution 5 ppm
  • Mathematical compensation of nonlinearities and temperature dependencies
  • Sturdy stainless steel housing (titanium or Hastelloy also available)
  • Extended lightning protection fitted to the SDI-12 interface as standard
  • Level measuring ranges from 0.3m to 300m. Higher ranges are possible using a Sub-Conn® connector
  • Ultra-high long-term stability

OEM Pressure Transmitters

The Series 4 LC…9 LC families of miniature OEM pressure transmitters combines a piezo resistive pressure sensor with -40…150 °C-capable signal conditioning in one compact, easy-to-integrate package.

The "LC" line of miniature pressure transmitters leverages Keller's extensive background in high-stability piezo-resistive pressure sensors and innovative digital signal processing. Now, both pressure sensor and signal processor are integrated into a miniature, hermetically-sealed housing no larger than was once required for the sensor only!

The name given to this new technology is Chip-In-Oil (CIO). CIO means not only that the entire pressure transmitter is embedded within a hermetically-sealed, oil-filled housing, but that this transmitter can then be seamlessly integrated into the OEM product, achieving cost savings and system performance not possible with other, conventional technologies.

Pressure Transmitters

Digital Output of Transmitter: This high precision of 0,01 %FS is available as an option (the standard Series 33 X has an accuracy of 0.05% FS). These Series are based on the stable, floating piezo-resistive transducer and the newly developed XEMICS micro-processor with integrated 16 bit A/D converter. Temperature dependencies and non-linearity of the sensor are mathematically compensated.

Transmitter with Analog Output: Integrated in the XEMICS processor is a D/A converter of 16 bit for analog signal outputs of 4…20 mA or 0…10 V. The output rate is 400 Hz. The accuracy is diminished by this converting process by 0.05% FS. The digital output is available on all transmitters with analog output.

Contact Details

KELLER AG für Druckmesstechnik
St. Gallerstrasse 119
Postfach 3238
8404 Winterthur
Tel: +41 (0)52 235 25 25
Fax: +41 (0)52 235 25 00