What is definition of non-rebreathable mask? What is definition of partial rebreathable mask? What is definition of ventury mask?

The first two types of masks,partial rebreather mask and a non-rebreather mask, are used in therapy with oxygen and belong to the tank category masks. These devices provide inspiration of the oxygen amounts below the usual amount of about 30 liters per minute.The two types of masks have a similar form, that both possess a pouch reservoir, filled with oxygen, and can provide oxygen concentrations higher than usual masks. The difference between the two masks is the existence of valves in non-rebreather mask, which are placed,one above a reservoir bag, inside the mask, and the other one, outside the mask, their goal being the release of expired CO2 ot of the mask.

Venturi mask it is a disposable mask, also used in oxygen therapy,  whose project is based on the Venturi  principle(narrowing of the inside diameter of a tube resulting in increased flow of fluid passing through the tube and a pressure difference) and allows administration of precise amounts of oxygen.