Oxygen, the gas essential for life, is far more complex in industrial applications than our daily inhalation and exhalation suggests. Industry ? especially in Fascinating , pharmaceutical or medical engineering fields ? is, over and over, finding itself met with new challenges in dealing with oxygen.
How come ?oil and grease free? so important in oxygen systems?
Oxygen itself isn’t flammable. However, it enables and encourages very strongly the combustion of other substances and may, in particular, result in a self-ignition of oil, grease along with other substances.
Materials which do not burn in air can burn very briskly and even spontaneously in oxygen or oxygen-enriched air. This stands, even though the enrichment is by way of a few percent.
Oil and grease (also ointments, gels and disinfectants) can react explosively in contact with oxygen.
Oxygen significantly increases the temperature of a flame and also the burn rate.
Special cleaning and testing procedures
Classification of contamination levels relative to ASTM G93-03:2004 ch. 11.4.3
As a manufacturer of high-quality measuring instruments, WIKA faces around the increased demands of these markets and develops special cleaning procedures specifically for its products. If, for example, a CPG1500 digital pressure gauge is supposed for oxygen service (option ?Oxygen, oil and grease free for oxygen applications?), before packing, the instrument will once more be cleaned additionally and taken up to the company?s own laboratory for residual hydrocarbon determination. As standard, in calibration technology, a hydrocarbon limit value of max. 200 mg/m� (per ISO 15001:2012) and for particles/fibers a limit value of 1000 �m is defined.
Steps in the calibration technology laboratory
The wetted parts ? specifically the pressure connection ? are rinsed having an extractant
The extractant is collected and analysed for foreign particles, and the hydrocarbon content is determined
A comparison of the measurement is completed with respect to the level classification relative to ASTM G93-03:2004 ch. 11.4.3
The wetted parts are rinsed again with an extractant
The extractant is collected and analysed for foreign particles, and the particle quantity is determined
The evaluation of the particle quantity is completed in accordance with ISO 15001 cat.1
Result of the procedure
Example certificate for CPG1500
The consequence of this determination, meaning the specific residual hydrocarbon content and number of particles, is documented in a 3.1 inspection certificate in accordance with DIN EN 10204 (see figure). The pressure connection of the cleaned and tested digital pressure gauge is provided with a protection cap. Subsequently, the entire instrument is sealed within foil. In addition, the merchandise label shows the choice ?oxygen, oil and grease free?. The determination of the residual hydrocarbon content is completed for every individual digital pressure gauge.
Note
More info on the CPG1500 can also be found on the WIKA website.

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