Return check valves  (click picture to enlarge) The sealing inlays are replaceable. All the nominal sizes are standard. Other sizes are available on request. Technical data and dimension sheets are available for all the series listed here. They can be read or downloaded as PDF files. Non-return valve Type: VR 15/16 Series: 083 Nominal diameter 15 - 100 and 65 - 600 Between-flange version with closing spring Data sheet.pdf (809 KB)* For liquid, gaseous and aggressive media, and also for use under problematic environmental conditions Sandwich non-return valves Type: RSK Series: 083 Nominal diameter 40 - 500  PN 10 / 16 Data sheet.pdf (495 KB)* Universally applicable to gaseous and liquid media, in oil, air or water systems, and in the chemical industry * These files require the Adobe Reader