I know some calcium reactors use gate vales to control the outflow; however that type of valve is not ideally designed for flow control. In real world applications gate valves are used for turning flow on and off. The valve seat tends to erode away if used for flow control. A ball valve will work well in this application. You can pick up a John Guest ball valve at Home Depot. I think they have 1/2” sizes.
I think the idea of only regulating the inflow on this type of reactor is there is a chance of churning the media to a powder if you regulate on the outflow. One valve is all you need.
Robert
Actuall Robert, most calicum reactors use a needle valve to control flow. For most other flow control applications a gate valve is prefered. A ball valve used for flow control will only work in the lower 10% of range. After that it's open season. As to the valve seat eroding away that will in fact happen, but only over many many years.
I noticed a comment back in this topic about using a lathe to "dress" the edges of the flanges on the phosban/media reactors for a more "store bought look". Myself and most other acrylic workers actually use a process called flame polishing. That however takes a bit of practice so I opted not to use or demonstrate it during the meeting last Saturday. If you're interested in learning the tricks than let me know and we'll get together and I can show you.