Why use an air muffler in a Freddy vacuum system joint

[kunalv]

Hello, I have borrowed a Freddy Vacuum Cleaning System from a friend since I wanted to use it on my CNC. We used it for removing the floating hydraulic oil from the coolant surface but it also sucks a lot of good coolant.

We then started looking for Freddy videos and found this -
Why have they used what looks like a Compressor Air Muffler in the joint section?

We built a simple U shaped pickup and fixed it to the tank to ensure it only collects oil from the surface, and connected it to the Freddy's vacuum suction hose with a simple tee and plugged the third port of the tee Like this -

It works fine but I would like to understand why a Muffler would be used in this.

Any help would be great. Thanks.

 

[Baluncore]

It works fine but I would like to understand why a Muffler would be used in this.

My guess would be to add more air to the liquid, for the uphill run towards the vacuum chamber.

Viscous liquid will pool at the low-point of the vacuum hose. Adding metered air through that valve reduces the fluid density and increases the bulk velocity of the froth in the line, so the oil does not separate and run back down to the pool.

It may not often be needed, but when it is there it is available. Do not throw it out until you are certain you know why it was there, and what exception it handled.

 

[TonyStewart]

Just like exhaust pipes, high-speed vacuum pipes will have acoustic standing wave resonances that a muffler will reduce the noise. This is more prominent (Q) when a solid section of pipe is used. I once tried a long vacuum hose on my '63 MGB as a kid with no muffler which led me to an understanding of resonance as a kid. Cars often have two mufflers, one called a resonator, the other a baffle.