?Oxygen, oil and grease free? in calibration technology

Oxygen, the gas essential for life, is a lot more complex in industrial applications than our daily inhalation and exhalation suggests. Industry ? especially in the chemical, pharmaceutical or medical engineering fields ? is, time and again, finding itself confronted with new challenges in working with oxygen.
How come ?oil and grease free? so important in oxygen systems?
Oxygen itself is not 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 usually do not burn in air can burn very briskly as well as 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.
Replicate 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 up to the increased demands of these markets and develops special cleaning procedures designed for its products. If, for instance, a CPG1500 digital pressure gauge is intended for oxygen service (option ?Oxygen, oil and grease free for oxygen applications?), before packing, the instrument will once again be cleaned additionally and taken up to the business?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 regards to the level classification in accordance with ASTM G93-03:2004 ch. 11.4.3
The wetted parts are rinsed again having an extractant
The extractant is collected and analysed for foreign particles, and the particle quantity is set
The evaluation of the particle quantity is carried out in accordance with ISO 15001 cat.1
Result of the procedure
Example certificate for CPG1500
The consequence of this determination, meaning the actual residual hydrocarbon content and amount of particles, is documented in a 3.1 inspection certificate in accordance with DIN EN 10204 (see figure). Dazzling of the cleaned and tested digital pressure gauge will get 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 carried out for every individual digital pressure gauge.
Note
Further information on the CPG1500 may also be found on the WIKA website.

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