This is a cross post from SFF. I'm hoping someone can give me some pointers. I want to use some quick release fittings on my next build. Looking at QD3’s from Koolance and my wallet started crying if I want to buy new. I started looking around and found these that are available locally for around half the price. https://www.flowfitonline.com/hydra...-set-14-bsp-dn04-iso-63-400-bar-rated-12-lmin These are designed with high pressure systems, but I would assume (and hence the open question) that they could also be used for low pressure systems like a watercooling loop? I have been scratching my head trying to compare them to the QD3 fittings reviewed here: http://thermalbench.com/2016/05/22/koolance-quick-disconnect-fittings/3/ The data sheet has values in BAR and LPM for the connectors and I think they are better (less restrictive), but I could be mistaken. Thoughts?
Aaaaand bookmarked They're not going to be as restrictive as a block or any different to qd3's I don't think. Found this video showing koolances flow meter, and on a d5 loop with an XSPC raystorm block they're getting 4.6 lpm, well within the rating of the fittings.
Careful, the values listed in the tables are max rates/pressures, not the pressure drop at a particular flow rate. That's in the teeny tiny little graph to the side, for which the steepest line is the linked 1/4" fittings (2 GPM ~ 7.5 L/min):
I think that's the graph for the other fittings that have a different aperture shape and size. The one I was basing it off is: That's also at BAR rather than PSI right? 1 Bar = 14.5 PSI which is a completely different scale. The thing that got me thinking the restriction would be low was the aperture size of 6.3mm, but I don't know if that's a red herring. As you can tell I'm a bit confused....
The aperture size doesn't necessarily correlate to the pressure drop for a given flow, as the internals of the QD valve may be wildly different (e.g. a more convoluted flow path will have a higher restriction for the same aperture). Good catch on PSE v. Bar, that puts the comparable area to the Thermalbench graph as a little square in the lower-left.
That's a good point on the aperture, I fully understand its only related to flow drop not proportional. After having an email convo with the supplier, I have ordered one set to test out with my pump. I'm planning to use a EKWB XTOP SPC 60 Plexi PWM but I may have to upgrade to a D5 if its too restrictive. Guess we will see.
Low pressure, high flow, double self sealing quick disconnect couplings are a bit niche. We have some at work from Swagelok and Staubli, but they are £££ (the Staubli are ~£100 per connector!). So most WC loops will achieve a max of 2 GPM. Usual loop calcs are based between 1 and 2 GPM, with 2 being the worst case scenario. L/min to UK GPM is 1:0.22, L/min to US GPM is 1:0.26. The graph supplied by Flowfit doesn't really cater for low flow and pressure. Using the conversion above, again worst case, we are looking at 3.7 L/Min @ 1 GPM US and 7.5 L/min @ 2 GPM US. Doing my best scaling on the graph - it looks to be around a 1 Bar pressure drop at 3.7 L/min and 1.2 Bar pressure drop at 7.5 L/min. *edit* - I've been sat here looking at this graph and the scale doesn't make sense - the numbers don't line up with the bar scale! The minimum pressure drop quoted for these fittings (on the crappy graph) is around 0.5 bar which is 7.25 PSI. That will be most of your pumps capacity. Interested to see how they work out in the real world. As much as the Koolance items seem like a lot of money (they are) I'm not sure if you'll find a better suited fitting for the price - just down to the usage case. There are some good resources for pressure drops on the web, and as an example (outdated, but figures are a useful guide): https://martinsliquidlab.wordpress.com/pump-planning-guide/ Hope that helps
In general D5 has a higher flow rate, but DDC has a higher head pressure. Specs differ between various iterations, but the 3.2 ddc pumps have 'all the pressure'.
My connector order arrived yesterday. Really nice heavy bit of kit. I just ordered a single fitting to try it out. I’m lacking a flow sensor so have ordered one from amazon. https://www.amazon.co.uk/gp/aw/d/B07HRYP2C3?ref=ppx_pt2_mob_b_prod_image Hope to have it delivered on Sunday so will test a loop with and without a connector to see flow difference.
Results in. Details in my build log. Thanks for the input guys! https://forums.bit-tech.net/index.php?threads/e-h2o-pt-1.362837/
