Oxygen, the gas needed for life, is far 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 met with new challenges in working with oxygen.
Why is ?oil and grease free? so important in oxygen systems?
Risky is not flammable. However, it enables and encourages very strongly the combustion of other substances and will, in particular, result in a self-ignition of oil, grease and 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 a few percent.
Oil and grease (also ointments, gels and disinfectants) can react explosively in touch with oxygen.
Oxygen significantly increases the temperature of a flame and also the burn rate.
Special cleaning and testing procedures
Classification of contamination levels in accordance with ASTM G93-03:2004 ch. 11.4.3
As a manufacturer of high-quality measuring instruments, WIKA faces around the increased demands of the markets and develops special cleaning procedures designed for its products. If, for example, 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 more be cleaned additionally and taken 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
An assessment of the measurement is carried out with respect to the level classification in accordance with 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 carried out in accordance with ISO 15001 cat.1
Consequence 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 relative to DIN EN 10204 (see figure). The pressure connection of the cleaned and tested digital pressure gauge is provided with a protection cap. Subsequently, the complete instrument is sealed within foil. Furthermore, the merchandise label shows the option ? Illegal , oil and grease free?. The determination of the rest of the hydrocarbon content is carried out for every individual digital pressure gauge.
Note
Further information on the CPG1500 can also be on the WIKA website.