For machine designers and developers, reduction of lifecycle cost is a critical factor. Condition monitoring systems play a key role in monitoring hydraulic oils and lubricating media to reduce downtime and introduce condition-oriented servicing. The online determination of particle content, water content and oil condition using cost-effective and rugged sensors provides an efficient method for continuous monitoring of the state of machines.
Particle contamination is the main cause of failure in hydraulic systems. Continuous recording of contamination has a significant advantage over the single analysis of an oil sample by vibration analysis as it monitors the oil condition over a period of time. The online measurement of particle count plays a decisive role in the detection of wear and prevention of damage. Particle sensors can detect problems months before production is affected.
With Hydac online measuring systems, the number and size of particles is determined with the help of optical detectors. These can be installed in both pressure lines and return lines. Advantages are their wide measuring range, accuracy, self-diagnosis capability and traceability to recognised calibration standards such as ISO 11943.
Hydac’s CS 1000 contamination sensor is the most advanced particle counter on the market. It is suitable for permanent installation in almost any lubricating oil or hydraulic system. The installation space required has been reduced by more than 50%. With features such as IP69K protection, resistance to vibration, load dump compensation and a high level of EMC compatibility, the CS 1000 is an ideal device for mobile applications. It is available with or without digital display and is also provided with various analog and switching out interfaces. It is pressure resistant up to 450 bar. A further feature is integrated oil temperature measurement.
Water is the greatest enemy of hydraulic and lubricating oils. Dissolved water is determined by means of humidity sensors. The basis is a capacitive measuring element with a humidity-sensitive layer. The related change in capacitance of the sensor is measured. Hydac’s AS 1000 and AS 2000 sensors can be installed in hydraulic and lubricating oil lines up to 50 bar. They are intended for use by OEMs in new machines and systems. Reduced to the size of a pressure sensor, they allow the continuous determination of humidity with an optimum price to performance ratio and can also measure the temperature of a fluid.
Free and emulsified water can also be determined precisely online using capacitive methods that measure the volumetric water content in the oil. Hydac’s AS 8000 for the measurement of free water is usually installed in the return line of existing systems.
The ageing of oil is a complex chemical process in which the basic fluid oxidises in a chain reaction under the influence of temperature and oxygen. Ageing can result in shortened filter service life and clogging of nozzles and lubricating channels, resulting in disastrous damage to systems. Such processes can be recognised at an early stage and prevented with the help of HydacLab, which is an oil condition sensor that measures viscosity, dielectric coefficient, humidity and temperature. The measured variables are made available to the user in the form of analog measured values and can activate switching outputs via triggers.
A filter’s degree of clogging can be measured continuously with the help of electronic pressure sensors which measure the system or inlet pressure as well as the differential pressure across the filter. Triggers can be set with the help of analogue and switching outputs, which can monitor, for example, the by-pass cracking pressure. The sensor also recognises whether a filter element is installed at all.
Hydac’s DirtController GW monitors filters and systems and can provide valuable information about long-term changes in a system. In conjunction with sensors for pressure, level and temperature, it is possible to implement complete condition monitoring. Different communication and visualisation interfaces via Internet and modem connection allow remote servicing and diagnosis. Data can be visualised and saved with the help of appropriate software tools.
A portable data recorder
To complement this range, Hydac’s HMG 500 portable measuring instrument for simple measuring tasks contributes to a systematic assessment strategy for hydraulic equipment. Up to two sensors can be connected to the HMG 500 with the Hydac Sensor Interface to measure pressure, temperature or flow rate. Finally, there is the HMG 3000, which is the high-end version. It can connect to ten sensors at a time and comes with a USB interface and serial interfaces for communication with a PC.
For more information contact Walter Heijboer, Hydac, +27 (0)11 723 9080, [email protected], www.hydac.com
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| www: | www.hydac.co.za |
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