# Matching Output of Two Old Ring Compressors using Larger Single Unit

Disclaimer: I am new in the design of any fluid systems, however the selection of these units is critical for the electrical design I am responsible for this system, so please excuse me if my approach is naive. We are running the system @ 480V 60Hz

We have an application where we are using Fuji Ring Compressors (https://americas.fujielectric.com/files/Fuji%20Electric%20VFC90.pdf) in a vacuum mode to hold aluminum panels up with vacuum belts. The outlet of the ring compressor goes into 3 chambers connected to the belt track. The belts have holes along the middle which provide enough suction force to hold up the panel. This method has proven to be successful in the past but we are expanding the number of belts, and would like to avoid simply adding more ring compressors (we would need 9 more units to expand the system in the same way, and we are short on space). What I am investigating is if we can use a larger compressor to match the outputs of two of these old units. This is the highest capactiy model that Fuji can offer in the same range (https://americas.fujielectric.com/wp-content/uploads/2017/05/VFB2000-7Wa-Single-Stage-Ring-Compressor.pdf).

My approach was to look at this from a black box perspective, and for now not worry about the force required to hold the panels, figuring out # of holes covering etc, since I know the singular ring compressor could handle it. My thought is that since the pressure is inversely proportional to area, I can simply compare the outlets of the units and the pressure they can supply at a given airflow. So I imagine a y-connector at the 4" outlet of the larger VFB unit splitting into two 3" lines representing two of the VFC units. If the vacuum generated at the end of those two 3" lines was greater than then what the VFC's could output, I can use the singular VFB unit.

The old VFC units have a 3" diameter outlet for an area of ~7.07 inches^2. The new VFB units have a 4" diameter outlet for an area of ~12.57 inches^2. If I am trying to match the output of two VFC units, I double the areas for those and compare the ratio (14.14/12.57 = 1.125). At any given point on the Flowrate/Pressure curves given in the datasheet, the pressure supplied by the VFB is greater than that ratio multiplied by the pressure supplied by the VFC by about 10-15%. I also anticipate less head loss in the lines because running one 4" line and splitting it should be more efficient then two 3" lines.

I still want to do the analysis back to the force required to hold panel, and required pressure at each vacuum hole etc, but I want to know if my idea is even remotely feasible before I spend too much time investigating. My main concern is the drop in vacuum flow at each hole, but I am not sure if this is a concern if I satisfy the vacuum requirements.