Vacuum degasser and poor boy degasser is both are degasser in oilfield, there are some differences some maybe confused.

How do the two degasser works and the difference

The vacuum degasser suck the drilling mud and separated mud and gas by vacuum pump.

Our vacuum degasser operates on a “thin strata” principle. The drill mud enters the tank and forces it to flow and distributed to a layer of internal baffle plates engineered to allow the liquid inside the vacuum degasser to flow as thin film and is exposed to the vacuum within the vessel. This layer of mud allows the gas to escape or break out of the mud . The vacuum pump releases the gas and discharge it to the disposal line. Mud exits the vessel under the action of the venturi and is returned to the mud system.

The poor boy worked by the physical characters.

The GN MUD/GAS SEPARATOR (poor boy degasser) consists of a cylindrical pressure vessel in a fixed vertical position. Inside is a series of specially angled baffle plates, stepped from the top to the bottom. When contaminated mud is routed into the separator, it flows downward successively over each plate. During this process, the heads of entrained gases “break out.” The released gas is then carried by the vent lines to a remote location where it can be safely flared.
The flow of liquid from the vessel can be regulated by a liquid-level-control valve or a U-tube, ensuring adequate retention time in the separator for the gas to break out.

Different Style and Different Looking

Here we set a few pictures to state this point. Maybe that sounds more.

Different Structure and Different Function

The mud gas separator is used before shale shaker, while the vacuum degasser is used after the shale shaker, so they have different function. The poor boy degasser usually used to separate the most dangerous gas, and the vacuum degasser is used only when we need more effective and more efficient results.