EPDM tube diffusers

[manu]

Hi,
Has anyone used EPDM tube diffusers in airlift pumps?
I have seen some reference about using disk diffusers,but did not see any actual designs. Tube seems like an easy and attractive option.
But installing a pipe(tube diffuser) inside the 110mm pvc pipe may need some skills.
Any suggestions

[Frank]

Hi,

I work with them. You need additionally a funnel.

Best regards,
Frank

[manu]

Hi Frank,
Thanks for your input. Can you please provide some details perhaps a drawing?
I read EPDM add bit more pressure to the system and have to factor in that while looking for pump. Any ideas?

[Frank]

You have another 20-30 mbar pressure, but that is unimportant, because the power consumption of the air pump goes down also.

Best regards,
Frank

[manu]

Frank,
This is a disk diffuser but what I meant was this.They are tubes.
I looked for proper design with the disk and could not find any. Then came across tubes seems attractive as they fit inside tubes easily in theory. But dont know how to do it.
https://www.oxyflex.de/en/produkte/rohr ... yflex-ms70

[Frank]

The discs are quite easy to use, the tubes are more difficult from my point of view.

https://images.app.goo.gl/b3ZoJBxEnuREceWG9

Best regards,
Frank

[manu]

Thanks Frank. Thats helpful.
also the data sheet support disk
"in contrast to the tube diffusers, the entire diffuser surface is on the same hydraulic level, the gas through put is even across the entire
membrane surface and control range. As a result, both the service life and performance are optimised"
do you recommend the fine bubble or coarse bubble model? I am planning to use a Gast 1531 pump with 30lpm flow,so may be 245mm(MT245) is enough ?

[Frank]

For increasing oxygen you need fine bubbles, for airlifts you take better take the coarse bubble disc. 245 mm ist enough.

Regards,
Frank

[manu]

Frank,
Sorry , did you mean 245 mm is enough?

[Frank]

Yes, the 245 mm disc is fine.

[manu]

Hum,finding it difficult to find the reducers from 245mm to 110 mm. Anyone know a source that make a 6 inch diffuser (150 mm)?

[Pssymon]

Hi,

There is a topic on the Belgian forum about building membrane disk Airlifts I believe. I will look for it and put up a translation here if possible.

The reducers at the size you mention can be difficult to find and expensive. Which is why members on the Belgian forum have made reducers using fibreglass. I'll have a look.

[Frank]

For a 110 mm airlift I would not use a disc. Drilling holes is the better way here.

Best regards,
Frank

[Pssymon]

I agree with Frank. What kind of flow are you looking for? Pressure chamber Airlifts can deliver up to 15000 or 20000 liters per hour. And may be the better / easier option for you.

To quote what I wrote elsewhere on the forum:

"The membrane disk Airlift

Another type of Airlift that some people like to use, is the membrane disk Airlift.
This type of Airlift is a bit more advanced.

Pros:
- Suitable for really high output up to 42.000 litres per hour from a single Airlift.

Cons:
- Requires a bigger pump to operate. Small air pumps lack the pressure required to open the membranes at depth.
- Slight drag due to having to keep the membrane disk open.

The membrane Airlift has been modified and tested many times. More detailed information will be posted in the appropiate section of the forum.
This Airlift is for those applications where huge output is the main goal."


Also, please have a look at this link where you can compare test results:
viewtopic.php?f=118&t=15803&p=253571#p253571

If I recall correctly Frank might even have some better results with membrane Airlifts.

[Frank]

Yes, the disc airlift are good for high output. At my pond I move 65.000 liter per hour with a 250 mm (10 inch) diameter airlift and 90 watt. Even more than 100.000 liters per hour would be possible with disc airlifts. But for a 110 mm pipe it's easier to drill the holes into the pipe instead of using a disc.

Best regards,
Frank