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ASCO's experience with other lines of valves, including the NS series, has demonstrated that the AC run in oil is not required. Water has proven to be an acceptable substitute for o-ring lubricant in static o-ring applications. The discontinued lubricants and area applied include:
AC core run in oil (Dow Corning 550)
O-ring lubricant used on static o-rings (Dow Corning 550)
Stem Lubricant used on seat/disc assemblies in the 206/208/210 series valves
(Neolube and Dow Corning 550)
ASCO will continue to use Neolube and Nyogel 775B for the u-cups/pistons on the NP8321 and NP8344 lines. These lubricants are required on these valves in order to provide proper lubrication and sealing of the dynamic seals. Nyogel 775D will also be used on the threads and flange of the explosion proof enclosure.
ASCO has also modified the standard seats and stems used in the 206/208/210 line of valves. The new seats and stems are plated with Nicotef (a proprietary coating of nickel and Teflon from Nimet Industries) which eliminates the requirement for lubricating the stems.
Since the seat disc is a change in design, ASCO has updated the catalog number of the valves to distinguish the new design. We have also taken this opportunity to standardize on the 8300 series numbering system in place of the prior 206/208/210 series of valves. A cross-reference list of valves is provided in Appendix B of this report.
With the exception of the 206/208/210 series of valves, additional testing to support the removal of lubricants was not necessary. The basis for this position is that lubrication of static o-ring is only necessary to assist in the assembly of the valve. Once the o-ring is in place, the lubricant no longer serves any purpose. ASCO has been able to substitute water for this purpose. The main advantage being that once assembled the water evaporates leaving no residue.
In the case of run in fluid on AC cores the primary purpose of this lubricant was to assist in the "wearing in” of the core and plug-nut during initial operation of the valve. As a result of improvements to the surface finishes of the core and plug-nuts ASCO has been able to eliminate the use of lubricant on these surfaces.
Testing was required for the use of the Nicotef as a substitute for the Neolube and DC550 used in the standard construction of the 206/208/210 series valves. Testing was conducted on valves representative of the two valve families, 5/16 and 3/16 inch orifice size valves. Both resilient and metal seated valves were included in the testing.