Hi Hive DIY and gardening enthusiasts! Here's another simple DIY project from Ligaya Garden. When you've finished reading the post (and hopefully upvoted it), please feel free to comment with any design changes or other uses that you might try for this project.
This one is about air lift pumps.
Lets' have a look!
In a recent Garden Journal update, I wrote about making a vortex style compost tea brewer. In that post, I wrote that the system is driven by an air lift pump. Since then, I've had a few folks asking about this style of pump on our Ligaya Garden website website and Instagram account so I thought I'd share some of the basic details here as well.
The basic idea.
An air lift pump is a simple thing that works by pumping bubbles of air into a vertical pipe in which water flows. The bubbles expand to the diameter of the pipe and lift the water immediately above them as they rise. It's about as simple a system as you can get.
The advantages of air lift pumps are-
- they are much cheaper than other styles of pumps
- you can make one easily anytime you have an air source that can create bubbles
- they run on a relatively low power input
- they have a low flow rate
- they oxygenate the water, meaning that you don't need an additional bubbler (they are excellent in aquariums).
When making an air pump there are two variables you will need to play around with if you want to make your own. These are pipe diameter and air flow rate.
You want the bubbles to be able to expand to the full internal diameter of the pipe so that they trap water above them as they rise. In the example that is in the post, initially I used 15mm PVC pipe and it worked but I found that I got a smoother flow with 20mm. Going to 25mm resulted in a much reduced flow rate.
For the 10 litre bucket setup that I was writing about, a 380 litre per hour aquarium air pump is just adequate to get things working well. Conventional air compressors don’t work well because, although you can get high air flow rates, their airflow is continuous and they are only designed to run in short bursts and overheat easily.
the vortex brewer written about in the post
Example of use