Vacuum Ejector

This is a vacuum ejector designed for compressed air to vacuum generation. Advantages of this type of vacuum generation is that it is instant when compressed air is applied it starts generating vacuum. Also, it can handle contaminants in the vacuum flow. As long as the contaminants being ingested in the vacuum port are smaller that the mixing tube diameter (3mm in this case) the ejector will not be blocked.

The input port injects compressed air that is exhausted on the output port. Air in the mixing chamber is entrained in the flow and a vacuum is developed. I have measured 18.5" of mercury (-9PSI) on the vacuum port with 0 flow. I don't have a flow gauge so I can't judge efficiency or flow with an open input.

Graphs with the input pressure and vacuum achieved are attached.

Both the compressed air input and vacuum ports are designed to be tapped with a 1/4" NPT thread. The wall taper matches the NPT thread and allows easy connection to air fittings.