Capped piston pump

A fluid pump comprising

• a piston chamber forming member having an inner end and an outer end,
• the inner end closed by a fragible membrane which, when unbroken, separates the inner end from fluid communication with a source of fluid and, when broken, places the inner end in fluid communication with the source of fluid,
• a piston forming element received in the piston chamber forming member axially slidable inwardly and outwardly whereby inward and outward reciprocal sliding of the piston forming element in the piston chamber forming member pumps fluid through the piston chamber forming member from the inner end to out the outer end,
• a cutting element carried on the piston forming element and extending axially inwardly towards the inner end of the piston chamber forming member,
• the piston forming element located in the piston chamber forming member in an initial position with the cutting element in the piston chamber forming member spaced from the membrane towards the outer end such that on axial sliding of the piston forming element towards the membrane, the cutting element engages the membrane and breaks the membrane.