Beckett skimmer doesnt work :(
 

I have a 4 becket skimmer with dual 10" risers. The total height of the skimmer is 26", due to the height limitations I had. It is being driven by a sequence hammerhead.

Basically, the skimmer doesn't skim. There seem to be some fatal flaws on the design that I believe can be corrected and make this thing pull some gunk.

This is a pic of the skimmer. It has the becket output pipes (not pictured) like the ones in the second picture. These outlets direct the output of the beckets into the risers. There is no baffle in the box seperating the two risers.

[IMG]http://reefcentral.com/gallery/data/500/3106Raj_skimanator2.JPG[/IMG]

[IMG]http://reefcentral.com/gallery/data/500/3106AS2_Hurricane.jpg[/IMG]

As you can see, the "collection cup" is not a traditional cup. The foam has to exit the small hole on the cap.

Please help me mod this skimmer!

Do you have any pics of it running?

i'm not familiar with the sequence hammerhead pump, but is it a pressure rated pump?

Thats one sweet looking skimmer! What kind of water did you have it in for testing? Did you try running just two of the injectors? I think running 4 of them on the one pump may be a stretch.

On my single beckett I use an Iwaki70 FWIW.

here is a pic of it running.

[IMG]http://reefcentral.com/gallery/data/500/3106DSC03398-sml.jpg[/IMG]

The becketts are pretty finicky. It takes a few days for the foam to rise to your second riser or the acrylic body to slime up with proteins. You might try to increase the foam height just a bit.

How long did you run it for? or are you still running it? If so, has the performance changed at all?

My first thought was, wow, that a lot of water flow through that skimmer and very short risers. I ran a dual beckett from MRC for a while with a pan world 200ps. But it had a 20" riser extension, for a total height of 4 feet.

To get to the point, my thought is that there is too much turbulence to build a good head of foam...just a thought...

Interesting, does any volume of foam really exit through that drain hole?

I am thinking has something to due with there is no tradtional collection cup. Without this where does the skimate collect? I can see that it being pushed out the hole as it created. I would make a collection cup and go from there.

timmye- One of the first mods I am working on is the collection cup. This one doesn't stand a chance to really collect. 99% of the foam won't exit the one tiny hole.

andycook- There is no foam exiting the drain hole.

fiziksgeek-I ran it for atleast 6 months. More than enought time to break in. When I took it apart, the inside of the riser was covered in thick crud; so with some modification, it is possible that this thing will skim.

dattack- adjustments aren't making a difference. I need a redesign.

So is there too much backpressure from the air not having anywhere to go?

got a movie of it in action you can upload? does the foam surface 'boil'? is the foam shot into the riser at an angle so it swirls like the second pic or is it shot straight in? it's probably just way too turbulent for that height in there for stuff to accumulate as a foam head without getting pulled back down by a turbulent surface. i don't like bubbleplates on tall skinny skimmers, but on a short fat one like this it might work well if the swirling doesn't smooth out the turbulence.

also, i'm really not sure a hammerhead is enough to split 4 ways. what happens when you only run one side? and what about only running 1 injector on each side?


the fact that foam doesn't blow out the hole makes me think the pumps are too small. i wouldn't worry about cups, but i would think about heating the top into a dome and putting the drain tube coming off the top center of the dome. collection cups are kinda pointless if you are going to put a drain on it anyway. if you think of the top of the neck on a cup as the 'point of no return' then what's the difference between that and a cupless design?- none. plus i bet it would make it much easier to make a wetneck on a cupless vs a cup.

Manderx-


I think the foam surface does "boil"

the foam is shot into the riser just like the second pic. I have tried it at an angle with it swirling and also pointed directly at the riser wall. Would it work better if it shoots down into the box instead?

According to sequence, the hammerhead is perfect for 4 beckets. There is no difference if I run only one side. I haven't tried running only one beckett per side though.

here are some pics of the inkectors if that will help.

[IMG]http://reefcentral.com/gallery/data/500/3106DSC03449.JPG[/IMG]

[IMG]http://reefcentral.com/gallery/data/500/3106DSC03448.JPG[/IMG]

[IMG]http://reefcentral.com/gallery/data/500/3106DSC03444.JPG[/IMG]

Who built the skimmer

Looks like a MRC but they all have collection cups and I am sure it is not a MRC.

The drains may not be big enough to handle the volume. My MRC MR-2 has a 1 1/2 outlet with a gate valve to tune it.

It does look alot like an MRC though. There is another company that makes a collection cup free skimmer just cant think on the name , but i didnt hear anything good about them.

Wow, another one...

I have helped people deal with this skimmer a few times now it seems. Forget who makes it, but from what I remember, the pipe coming out of the beckett is 1/2".... too small and it makes alot of back-pressure on the injector (why its filling with water). The injectors need 1" pipe to connect to the body, then you will be fine.

My thought is, the simpler the design, the better it works. The more feature, the more finicky, and the less efficient. JMO

Alex

Maybe try turning the feed pump back some with a gate valve on the output.

Also, I see the water is a little high in that one pic and appears higher than the inlet holes for the air. If it is sucking air, the water line in the injector housing should be below those holes. Mine will sometimes raise if the injector is getting clogged up. It's as if it can't pump the water through the injector fast enough so it's spilling out the holes.

That is one issue with the becketts that they need taken apart and cleaned a couple times a week. Sometimes this will happen in the first few minutes if the feed pump picks up some debris.

An impressive skimmer.... I hope you can get it to work for you. What are you doing in the meanwhile? Waterchanges? smaller skimmer?

Hahn' the inlet and outlet on my injectors are 1", they're not like the one's pictured above.

BUT, as you can see, the housing still fills with water.

Hey Skriz, on my MR-2 there is an O ring on the bottom where the beckett goes into the hole. I don't know if it is there to hold the beckett together or create a seal. If you turn off the air supply is the level in the beckett chamber the same as the reaction chamber? Is the height in the reaction chamber controlled by a gate valve like a MRC skimmer?

Did you ever call Tim?

I'm pretty sure that the lack of a conventional collection cup is not the problem. Reefconcepts, the guys that make the Aerofoamer beckett skimmers, use the same type of collection device the skimmer on this thread.

hmm, so what's your take on the "swirl effect" ? Aerofoamer claims that the swirling is good. I thought that it was bad?

The collection cup probably is not the main problem, but it does seem highly inefficient. On a traditional cup, the foam has 360 degrees of eixt space. In the above design, the exit space it limited to maybe 2-3 degrees, the rest of the foam does what?