Filtration head for vacuum filtration, manifold for vacuum filtration and method of modifying an existing filtration head for vacuum filtration

A filtration head (1) for vacuum filtration, the filtration head (1) comprising:

• a receptacle for a support (2) for a membrane filter (3) for microbiological testing of a liquid substance to be drawn from an upstream side of the membrane filter (3) to a downstream side of the membrane filter (3) through the membrane filter (3), or the support (2) for such membrane filter (3);
• a drain chamber (4) located downstream of the support (2) and communicating with a downstream side of the membrane filter (3) when the membrane filter (3) is in place on the support (2) to receive the liquid substance that has passed through the membrane filter (3);
• a drain channel (5) communicating with the drain chamber (4) at an opening (9) and having an outlet intended to communicate, in use, with downstream equipment including a vacuum pump to drain the liquid substance;
• and
• a shield (6) comprising a body and an expanded head portion which is arranged in the drain channel (5) of the filtration head (1) so as to block/interfere a fluid path between the opening (9) of the drain channel (5) and the outlet of the drain channel (5), while permanently retaining a fluid path (7) through the drain channel (5) past the shield (6), wherein the expanded head portion is positioned adjacent the opening (9) of the drain channel (5).