Mag-Lock collection cup design

[ejmeier]

I'm not sure if this has been tried before, but I thought I'd post this to get some input.

Basically, a collection cup does not have to have a seal so tight that it holds city water pressure in the ranges of 50 - 70 PSI. It just has to be water-tight enough to keep out foam - and if you run the skimmer quite wet - then maybe a few inches of water. That is like .25 PSI, almost nothing.

Anyway, my idea was to imbed magnets into both the collection cup, and the recieving flange. The magnetic pull would be strong enough, (in theory, and depending on which magnets you use), to create a seal with an o-ring. It is similar to keyhole flange designs, only instead of a keyhole, you have a pair of magnets, one on each mating piece.

I drew a quick drawing in Google Sketch-Up. (Keep in mind I am total novice when it comes to CAD....) :rolleyes:


The collection cup half:
http://reefcentral.com/gallery/data/500/23334cc-med.jpg


The skimmer body half:
http://reefcentral.com/gallery/data/500/23334flange_base-med.jpg


Advantages of this propsed design are:
-Zero clearance needed to remove the cup
-Simply grab the cup firmly, and it lifts off the base - couldn't be easier
-No CNC tools needed to machine the parts like twist-lock
-Fairly quick and inexpensive fabrication of parts

Potential downfalls:
-Possibly hard to find the right balance between magnets being too strong (difficult to remove CC cup) and too weak (leaks)
-Magnets could contact tank water if something falls off

That's it. I think this design is very doable once all of the trial and error is worked out on magnet sizing. You could just use a forstner bit to drill 1/2 way through the plate and glue the magnet in. I'd probably want the magnet to pull *into* the acrylic and away from the drilled hole, to prevent it from ever coming loose.

[Donw]

I tried it with 12 dime sized rare earth magnets, it works ok. Probably about as good as the seal on on my asm.

Don

[RichConley]

EJmeir, great idea. At this point, the biggest expense on medium sized DIY skimmers is th $60-100 you have to spend on a 4-6" union. If we can get rid of that, it makes a huge difference in costs.

[ejmeier]

I think on the lower half, which is connect to the skimmer's body, you can easily upsize the magnet's power by buying magnets that are DEEPER. (Still the same diameter though.) They would just protrude farther below the flange ring.

I would think you could get too strong though, and then the cup might come off with a huge jerk, spilling sick skimmate all over. :(

[angels mcgee]

ejmeier,

as long as you turn it off and the top of the collection cup is on you should be fine right? I mean the riser tube doesn't leave the collection cup.

[ejmeier]

I guess it would come off a lot more smoothly if you turned it about 30 degrees first - I didn't think of that. I was thinking if you tried to pull it straight off, sort of like you do with a strong refrigerator magnet, there is a sudden jerk when it lets go.

I guess then the only problem I can think of would be possible wear and tear on the o-ring.

[BeanAnimal]

I built exactly such a design several months ago when working on my 6" PVC skimmer (I think it was even mentioned in the thread). It worked well, but to be honest I scrapped the idea in favor of a keyed flange. To get a good seal, I needed to use a fairly large size magnets and several around the perimeter of the flange. I use neo magnets for all kinds of things like that... I am almost like a kid in a candy store when I order magnets... I get yelled at for leaving them in pockets... she finds pants stuck to the washer or dryer... sometimes to the front of the washer when she tries to load it. I even had a neo magnet pull my shorts into an electric drill one time. Anyway...

I used a forestner bit and made the pockets slightly oversized so that alignment was not an issue. The magnets were allowed to float back and forth a tiny bit. The prototype was simply the two flange rings, but the bottom one did not have a hole on it. I attached a pice of pipe to the top flange so that I could simulate head pressure on the o-ring seal.

Like I said it worked, but the magnetism had to be kinda strong... that made removing the cup somewhat awkward. My collection cup holds 1.5 gallons... a sloshing spill would be very messy!

Turnig the cup slightly does help to remove it, but getting any part of the flange close to the skimmer body will cause the cup to pull to one side...

I even toyed around with the idea of an electromagnet (went as far as drawing up the prototype and ordered a pile of magnet wire from a surpluss friend). In the end the keyed flange was the easiest.

Bean


Bean

[BruiseAndy]

To help take pumps apart there are threaded holes in the plate that attatches them together. You thread a bolt in one plate and it pushes against a flat part of the other. You could just thread the bottom plate and run a nylon screw up to break the magnetic pull.

[BeanAnimal]

I thought about a simple hinged cam and lever that would lift one side of the cup... simple, elegant, a PITA compared to a keyed flange. As would be turning evne a course threaded release screw.

I use magnets for speakers grills, hidden access panels, clamps, and 2 dozen other things. I am sure with some thought they could be made usefull on the skimmer neck... but after a few hours of toying around with the idea, well I could not see any real benefit.

Bean