Oxygen, the gas essential 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, over and over, finding itself met with new challenges in dealing with oxygen.
Why is ? Cover-up 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 can, in particular, cause a self-ignition of oil, grease and other substances.
Materials which usually 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 only by way of a few percent.
Oil and grease (also ointments, gels and disinfectants) can react explosively in contact with oxygen.
Inferior escalates 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 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 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 with an extractant
The extractant is collected and analysed for foreign particles, and the hydrocarbon content is determined
An assessment of the measurement is completed with regards 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 set
The evaluation of the particle quantity is completed in accordance with ISO 15001 cat.1
Consequence of the procedure
Example certificate for CPG1500
The consequence of this determination, meaning the specific 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 will get a protection cap. Subsequently, the entire instrument is sealed within foil. Furthermore, the product label shows the option ?oxygen, oil and grease free?. The determination of the rest of the hydrocarbon content is carried out for each individual digital pressure gauge.
Note
Further information on the CPG1500 may also be on the WIKA website.