Valve assembly

A valve assembly comprising a valve body and a mono-material plunger, wherein:

• the valve body has a primary opening and a secondary opening, wherein the primary opening and the secondary opening are axially spaced apart;
• the plunger comprises:
• a primary seal portion configured to selectively occlude the primary opening;
• and
• a secondary seal portion configured to selectively occlude the secondary opening;
• and
• wherein the plunger comprises the following operational positions with respect to the valve body:
• a transit seal position in which:
• the primary seal portion of the plunger is in contact with the valve body in order to occlude the primary opening;
• and a fluid flow position in which:
• the primary seal portion of the plunger is spaced apart from the valve body such that fluid can flow through the primary opening;
• the secondary seal portion of the plunger is spaced apart from the valve body such that fluid can flow through the secondary opening;
• and
• the plunger is maintained in the fluid flow position by an external force and a force caused by a pressure differential across the valve assembly.