Venturi vacuum generators use compressed air to create vacuum. They are simple to integrate into an air supply system, you just need to plug in a compressed air line to operate them. They can be used to transport certain fluids and powders, e.g. flour, sawdust, or even food products. As they do not require electricity, they can be safely used in hazardous environments.
There are adjustable models available which modify the capacity and vacuum level of the device without adjusting air pressure. Both types come in a range of sizes.