It is an air gap that allows air to escape rather than building up in the pipe and creating an air hammer within the pipes (banging noise), and problems with drainage. (think about pouring out of a can that doesnt have the second hole punched in it.
Suction Therapy : Suction therapy is provided to assist in the removal of bronchial secretions that cannot be expectorated by the patient spontaneously. Suct...
The more traditional method, however, creates suction by applying heat to the cupâsuch as from a lighted candleâhence the name âfire cuppingâ. Usually, a number of suctioning cups are applied to the patientâs skin for several minutes and then removed.