Abstract: One end of a hollow cylindrical tube is attached to a tubing positionable in a patient's body. A radial flange on the tube supports a collar in abutting relationship to one flange surface. Lugs extend integrally from the collar through the flange for disposition against the opposite flange surface. The collar extends radially past the tube's inner periphery and has slots at its inner periphery. Stops integral with the inner periphery of the collar are annularly displaced relative to the slots. Ramps on the collar lead to the stops. A piston in the tube along part of its length has, at the end within the tube, a sleeve in sealed relationship with the tube is inner periphery. Splines have grooves at spaced positions along their axial lengths at the radially outer ends of the splines. A handle at the piston axial end has an aperture to receive a user's finger for manual adjustment of the piston axially relative to the tube.

Abstract: A cervical dilator assembly features a captive extraction element in the form of a collar press-fitted over one end of an insertion element made of the self-swelling vegetable stalk laminaria japonica. A withdrawal cord is affixed to the collar, the collar being captively retained in the swollen condition of the inserted dilator element so that pull on the cord causes withdrawal of the inserted dilator element without rupture or tearing thereof. In the preferred form of the invention the collar is fabricated in the form of a migration-limiting disc.

Abstract: An aluminium valve which has a seat of stainless steel. This seat is provided by friction welding stainless steel onto aluminium and then shaping the composite to size. The stainless steel can be covered with stellite. The valve is closed by abutment of a PTFE bush onto the seats. The seat can comprise a slope so that any contaminatory material tends to be forced off the seat by the bush in use.