The best-known application for slotted oil scraper rings is as the bottom ring of the three types on a piston within a combustion engine. This type of piston ring ensures the same distribution of oil over the cylinder wall and the removal of the excess oil to the crankcase through the recesses in the ring.
The piston also has channels through which this oil can flow back to the crankcase. Another part of the oil is scraped back through the cylinder wall. The classic version is a single piston ring with or without tension ring.
Nowadays, the three-piece piston rings are often used in which a central inner ring presses two narrower piston rings, in place and with tension, against the cylinder wall. We also refer to this type as Niflex rings. The narrow working rings in this system are made of steel and provided with a hard chrome or nitride coating after treatment.
Applied materials include:
- Lamellar and nodular cast iron
- Various steel grades
Standards:
- NEN ISO 6627: 2000
- NEN ISO 6625: 1986
Special surface layers:
- Hard chrome
- Bath and plasma nitriding
- PVD layers
- DLC layers
Type E301 – Slotted oil scraper ring with narrow oil grooves. 
Type E302 – Slotted oil scraper ring with wide oil grooves. 
Type E303 – Slotted oil scraper ring with wide oil grooves & rounded slots. 
Type E304 – Slotted oil scraper ring with tapered oil grooves. 
Type E305 – Wide stepped slotted oil scraper ring. 
Type E306 – Double bevelled oil scraper ring. 
Type E307 – Double bevelled oil scraper ring with scraping grooves. 
Type E308 – Roof bevelled slotted oil scraper ring. 
Type E309 – Bevelled oil scraper ring with expander spring. 
Type E310 – Slotted oil scraper ring with offset runnig face. 
Type E311 – Double slotted oil scraper ring. 
Type E312 – Offset oil scraper ring with wide oil groove. 
Type E313 – Slotted oil scraper ring with wide oil grooves & expander spring.