Oxygen, the gas essential for life, is far more complex in industrial applications than our day to day inhalation and exhalation suggests. Ironclad ? especially in the chemical, pharmaceutical or medical engineering fields ? is, over and over, finding itself confronted with new challenges in working with oxygen.
Why is ?oil and grease free? so important in oxygen systems?
Astonishing isn’t flammable. However, it enables and encourages very strongly the combustion of other substances and will, in particular, cause a self-ignition of oil, grease and other substances.
Materials which do not burn in air can burn very briskly or even spontaneously in oxygen or oxygen-enriched air. This stands, even when the enrichment is by way of a few percent.
Step-by-step and grease (also ointments, gels and disinfectants) can react explosively in contact with oxygen.
Oxygen significantly escalates the temperature of a flame plus 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 up to the increased demands of these markets and develops special cleaning procedures specifically 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 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 set
An assessment of the measurement is carried out with regards to the level classification relative to 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 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 result 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 will get a protection cap. Subsequently, the complete instrument is sealed within foil. Furthermore, the merchandise label shows the option ?oxygen, oil and grease free?. The determination of the residual hydrocarbon content is completed for every individual digital pressure gauge.
Note
Further information on the CPG1500 can also be found on the WIKA website.