Removable manifold for a medical/surgical waste collection system, the manifold including tabs that facilitate the alignment of the manifold

There is disclosed a method of opening a valve in a medical/surgical waste collection unit, the medical/surgical waste collection unit including a vacuum pump and a receiver defining a bore, the receiver including a valve disk, the valve disk including an actuating member, the receiver further including a lock ring having at least two slots, the method comprising: providing a manifold having a base at a proximal end, the base defining an opening, the opening being off center from an axis of the manifold, and the manifold further including two arcuately spaced tabs, wherein each of the tabs subtend arcs having different arcuate lengths; positioning the manifold such that the tabs of the manifold mate with the at least two slots of the lock ring so as to cause the opening of the manifold to be, upon insertion into the bore, in a specific rotational alignment in the bore; and rotating the manifold within the bore to cause the valve disk to move between a first position in which the valve disk blocks fluid flow through the receiver and a second position in which the valve disk allows fluid flow through the receiver.