I don't know what they call them but when I used to use a waterer like that, I used a pipe securing ring from the hardware store. They have a screw-in tightener on the side so I was able to make it very tight and it worked great. I tied wire to each side and it held up like a charm. I really think you would be better off with a waterer that takes less time to clean and easier to fill/maintain. The waterers like the one you have end up being a lot of work - grow green stuff quick, get a lot of dirt/poop in them, plus they take up a lot of space. Chicken waterer cups are up against the wall and out of the way and the small cups do not collect much dirt plus are easy to clean, just swipe your finger through and they are clean.
I would stick with what you have, just don't get more of them and if it ends up being a pain, upgrade.