SUN cartridges and low temperatures
Recently we got a request from the customer to check the system components to work in a low-temperature environment up to -40°C. Most components in the customer’s system were SUN cartridges.
And I was really surprised by the mess of info on the Sun Hydraulic website about seals that SUN uses in their cartridges.
For example, on the “Seals: Materials of Construction” page you can find the manufacturer’s temperature range: from -22° to 230° F (-30° to 110° C) for Buna N (Nitrile) and -22 to 260° F (-30 to 125°C) for Polyurethane O-rings.
But, if you download Technical Product Information PDF from their library, you can find different temperature range for Buna N: -50°F to 200°F which means -45°C..+93°C and no info about Polyurethane O-rings.
This is why I was confused and had a lot of questions to SUN:
1. Why the different info is provided on SUN website?
2. Why there isn’t a choice for Polyurethane O-rings in seal material when selecting cartridges in the SUN catalog?
3. Why SUN has so high temperatures for the low environment for both Buna N and Polyurethane seals?
Really, all competitors have better low-temperature limits for their cartridges, for example:
– Parker’s Nitrile: from -40°C to +93.3°C
– Danfoss/Comatrol, Buna-N: from -40°C
– Bucher, Buna “N”: from -40°C to +120°C
– Doering, Buna N: from -42.7°C to +93.3°C
– Eaton, Buna N: from -40°C to +120°C
– Hydraforce’ Buna “N”: -40°C to +100°C; polyurethane: -54°C to +107°C.
Because it was critical for my application, I have sent a request directly to SUN to get answers to the questions above and have gotten next response: the correct low work temperature for Buna N is -30°C. Сoncerning the polyurethane seals – this is not a standard option, but any cartridge can be assembled with polyurethane o-rings that provides low temperature rate to -40°C. Not a big difference in the price, but because this is going to be a custom modification the delivery time for cartridges (statement on November 2021) is 15..16 weeks (what actually is not bad for SUN).
Just would like to share this experience with you…
Working on the design of new projects I like to involve SUN Hydraulics valves and use them a lot. They are not expensive, pretty reliable and have uncredible understandable paper and online catalogs.