This is the blog of Ronald Bartels that wanders on and off the subject of problem management (that is how it started), but it is best described by Ray who says this is Daddy's thoughts! Like the best music is from the Eighties and a wee dram helps in solving most inconveniences.
Vacuum Breakers: Understanding how they protect our water
The most basic form of protection is the presence of an air gap in
between the possible source of contamination and access to the plumbing
The atmospheric vacuum breaker consists of a check valve member and an
air vent that is normally closed when the device is pressurized
A hose connection vacuum breaker should be installed on each faucet or
hose bibb that is connected to the potable water supply.