PP Nitrox rig - Special Hyperfilter cartridges?

Deepthought

Hi,

Trying to get some info on Hyperfiltration cartridges and it's a bit thin on the ground.

Where I'm going with this is;-

I have a 35" filter tower (with check and priority valve) from a previous compressor (Bauer / Mako type)

Intending to setup a Partial Pressure rig and plumb this onto a manifold with whips and an O2 cylinder (I know many people cascade 2 or 3 o2 bottles so will ensure spare inputs for future use). will be O2 cleaned and redundant one way valves to ensure safety, I have some line valves and needle valves already.

The compressor passes its quality checks fine but I was going to use either another desicant/charcoal/CO cartridge or if it will fit the existing canister, a hyperfilter cartridge.


Where this gets confusing is there is some info out there to suggest you can't use a standard tower as the cartridge needs to recirculate the flow -

Don't know if this is a marketing ploy or some special ritual performed on the tower involving chalk Pentagrams, black candles and sacrificial goats .

If not could the existing tower be modified e.g. drill a small hole of diameter x at position y ... (I'm hoping this is the case, going to be a few months 'till the next shipment of goats arrives)

The bright sparks out there are probably thinking why not use a premix stick before the compressor... Good idea except that there is a manifold and bank cascade system and we do lots of plain air and I don't propose to rebuild that system to prevent accidental filling of the banks with Nitrox. Plus I understand such a system brings the service intervals for the compressor forward by a variable percentage. There's also the fact that we need to occasionally decant into the small O2 kit bottles for the boat (and the stick idea wouldn't be able to give me the occasional "rich" nitrox for my SCC's but don't tell the Boss thats why I volunteered for this project ).

Thanks

Asking questions is a good idea - But getting the right answer implies asking the right questions

cool_hardware52

A typical tower directs the gas flow up the center of the cartridge, out the top of the cartridge and back down to the base of the tower in the space between the cartridge and the ID of the tower.

In a Hyperfilter this is reversed to reduce the chances the filtered gas will pick up contaminates from the inside surfaces of the tower. Hyperfilters have the flow so it goes up between the can and the cart, in the top of the cart and down through the filter, exiting through the center nipple the cartridge sit on.

If you run a conventional tower backwards, i.e. use the inlet for the outlet you will get the flow in the proper direction for hyperfilter.

You need to make sure your appliance does not have restrictors or checks in the fittings.

I'd call LF. Tell them what appliance you have and they can build you whatever you need in the way of cartridges.

Keep in mind that your Hyperfilter needs Grade E as input gas so you will need conventional filtration ahead of the hyperfilter.

Tobin

Deepthought

Thanks

Yes, the compressor has it's own pair of filters, I use the LF filters in there - they come in at around 32 bucks and do about 45 hrs.

Anything extra/different in a Hyperfilter cartridge ? We're on Cayman in the middle of the Caribbean so things are never as easy as calling a supplier and getting stuff delivered in a couple of days by USPS.

IF I didn't reverse the flow and instead meticulously cleaned the inside of the tower and then used off the shelf cartridges, how close would that be ?
Don't worry - still going to talk to LF but a second opinion is always appreciated.

cool_hardware52

You are of course asking a question that cannot be answered quantitatively without gas analysis.

On the other hand if the question is "will additional filtration get my gas clean enough to allow for careful PP blending" the answer is lots of folks are doing exactly that.

A typical single tower filtration system cartridge may include a coalescing separator, desiccant, CO catalyst, and Activated charcoal.

A hyperfilter is not simply more of the same.

I wouldn't sweat running the "last" tower in the conventional manner, i.e. up the center and down the outside, just clean the can well when you service the tower.

Tobin