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 produced vacuum creates a suction effect that increases blood circulation to the local area, relaxes muscle tissue and releases a myriad pain causing factors. Cupping Therapy softens tight muscles, tones attachments, loosens adhesions and lifts connective tissue by creating suction and negative pressure.