Pogosta vprašanja glede brez-oljnega zraka in razreda 0
What are the TÜV tests required to qualify for ISO 8573-1 CLASS 0?
The Part 2 test measures aerosols and liquids. Testing can be done through partial flow (B2) or full flow (B1) methods (see below). The Part 5 test measures vapor only. Both parts are necessary to obtain ISO 8573 CLASS 0 certification. This means that all three sources of oil contamination – aerosol, vapor, and liquid – have to be measured.
What is the essential difference between partial flow (B2) and full flow (B1) testing methods?
Both methods are acceptable for aerosol and liquid measurement according to ISO 8573-1 Part 2 The B2 method targets only the center of the airflow. Oil aerosols are registered but oil that sticks to the pipe wall (wall flow) is not detected. Most air compressor manufacturers still prefer this less stringent method. The B1 method examines the entire air flow to measure both aerosols and wall flow. This comprehensive test method was used on the Atlas Copco range of oil-free air compressors. Even so, no traces of oil were found in the output air stream.
Can oil-injected compressors with oil removal filters deliver oil-free air?
This solution is often referred to as “technically oil-free air”. However, even under optimum conditions and with several stages of oil removal, the air quality with regard to oil is suspect. To achieve even barely acceptable air quality with oil-injected compressors, it is necessary to have air-cooling devices and several stages of oil removal with multiple components.
A failure of any of these components or inadequate maintenance can result in oil contamination of a process. With oil-injected compressors, there will always be a risk of contamination and the possibility of severe consequences for the business.
What is the impact of ambient temperature?
One aspect influencing the efficiency and purity of air systems is temperature. When using oil-injected compressors with oil removal filters, oil carryover through filter media increases exponentially according to the temperature at the filtration interface. If the ambient temperature in the compressor room increases to 30°C, the compressor outlet temperature could be 40°C with the oil carryover 20 times the specified value. Such temperatures are not unusual even in colder countries, where the compressor room temperature is substantially higher than that outside.
Temperatures also cause an increase in the vapor content of the air, some of which can carry through to the end product. Moreover, high temperatures shorten the lifetime of activated carbon filters. An increase in temperature from 20°C to 40°C can cut filter lifetime by up to 90%. Even worse, the activated carbon filter does not warn the user when it is saturated. It will simply allow oil to pass on to processes. For Atlas Copco’s oil-free compressors, air quality is independent of temperature.
What about oil contamination in ambient air?
Ambient air has very small traces of oil coming from vehicles and industrial sources. However, in contaminated areas, oil content does not normally exceed 0.003 mg/m3. This is borne out by tests conducted by the TÜV near a factory with heavy machining activity (including turning, milling, grinding and drilling).
Heavy vehicular traffic and a garbage incinerator were in the vicinity. Aspirated by an oil-free compressor, this extremely low level of atmospheric oil is almost completely washed away by the condensate in the intercooler and aftercooler, resulting in pure oil-free air for your process.
Kateri testi TÜV so potrebni za izpolnjevanje pogojev za ISO 8573-1 RAZRED 0?
Drugi del testa testira aerosole in tekočine. Testiranje se lahko izvede z metodami delnega pretoka (B2) ali s celotnim pretokom (B1) (glej spodaj). Peti del testa meri samo hlape. Oba dela sta potrebna za pridobitev certifikata ISO 8573 CLASS 0. To pomeni, da je treba izmeriti vse tri vire onesnaženja z oljem - aerosol, hlapi in tekočine.
Kakšna je bistvena razlika med testnimi metodami z delnim pretokom (B2) in polnim pretokom (B1)?
Obe metodi sta v skladu z ISO 8573-1 sprejemljivi za merjenje aerosolov in tekočin - drugi del. Metoda B2 cilja samo na sredino pretoka zraka. Oljni aerosoli so registrirani, vendar olje, ki se prilepi na steno cevi (pretok stene), ni zaznano. Večina proizvajalcev zračnih kompresorjev še vedno raje uporablja to manj strogo metodo. Metoda B1 pregleduje celoten pretok zraka za merjenje tako aerosolov kot pretoka sten. Ta celovita preskusna metoda je bila uporabljena na liniji zračnih brez-oljnih kompresorjev Atlas Copco. Kljub temu ni bilo najdenih sledi olja v izhodnem zračnem toku.
Ali lahko oljni kompresorji (kompresorji z vbrizgom olja) s filtri za odstranjevanje olja dostavijo zrak brez olja?
Ta rešitev se pogosto imenuje "zrak brez tehničnega olja". Vendar pa tudi v optimalnih pogojih in z več fazami odstranjevanja olja obstaja sum o kakovosti zraka v zvezi z oljem. Da bi dosegli dokaj sprejemljivo kakovost zraka z oljnimi kompresorji, je treba imeti naprave za hlajenje zraka in več stopenj odstranjevanja olja z več komponentami. V primeru okvare katere koli od teh komponent ali neustrezno vzdrževanje le teh, lahko povzroči kontaminacijo olja v postopku. Z oljnimi kompresorji vedno obstaja nevarnost kontaminacije in možnost resnih posledic za poslovanje.
Kakšen je vpliv temperature okolice?
En vidik, ki vpliva na učinkovitost in čistost zračnih sistemov, je temperatura. Pri uporabi oljnih kompresorjev s filtri za odstranjevanje olja se prenos olja skozi filtrirne medije eksponentno poveča glede na temperaturo na filtracijskem vmesniku. Če se temperatura kompresorja v prostoru poveča na 30 ° C, bi lahko izstopna temperatura kompresorja znašala 40 ° C s prenosom olja 20-krat večjo od navedene vrednosti. Takšne temperature niso nič nenavadnega tudi v hladnejših državah, kjer je temperatura kompresorja bistveno višja od temperature zunaj. Temperature povzročajo tudi povečanje vsebnosti hlapov v zraku, od katerih se nekateri lahko prenesejo do končnega izdelka. Poleg tega visoke temperature skrajšajo življenjsko dobo filtrov z aktivnim ogljem. Povišanje temperature z 20 ° C na 40 ° C lahko skrajša življenjsko dobo filtra do 90%. Še huje je, da filter z aktivnim ogljem uporabnika ne opozori, ko je nasičen. V tem primeru se olje prenese na procese. Pri brez-oljnih kompresorjih Atlas Copco je kakovost zraka neodvisna od temperature.
Kaj pa onesnaženje z oljem v zraku okolice?
V zunanjem zraku so zelo majhne sledi olja, ki prihajajo iz vozil in industrijskih virov. Vendar na onesnaženih območjih vsebnost olja običajno ne presega 0,003 mg / m3. To potrjujejo testi, ki jih je TÜV opravil v bližini tovarne s težkimi obdelovalnimi aktivnostmi (vključno s struženjem, rezkanjem, brušenjem in vrtanjem). V bližini je bil močan promet in sežigalnica smeti. Kondenzat v hladilniku in hladilniku skoraj popolnoma izpere atmosfersko olje, s pomočjo brez-oljnega kompresorja, kar povzroči čist zrak brez olja za vaš postopek.