Vacuum Breaker Valve

What is vacuum breaker valve, and how does it work in aircraft lavatory system?

I would like to see an IPC image or Maintenance Manual reference.

"If" your aircraft have a vacuum lavatory system, there is a large tank (usually) located back near the aft pressure bulkhead. This tank will have a suction pump located on it. Tubing from each lav is connected to the tank. When a toilet is flushed, a blade valve will open on the bottom of the toilet. At the same time the vacuum pump will turn on. This should draw any contents into the tubing leading to the tank.

I'm not sure what Boeing calls the "breaker valve" in this system. My guess would be the blade valve, but an image should provide the answer.

I have just sent an email with enclosed pages of the catalogue

Well..... these images show individual tanks for each toilet, so my previous guess was wrong.

I'll post the images , but without referencing the maintenance manual, I can't tell you the function of the valve.

To be truthful, I avoid this particular subject in chapter 38 with a passion.
  
     
  
     
 

This is all I found from 38-32 in AMM.