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…