Abstract: A filter for covering a surgical orifice at a base of the neck of a tracheotomized person and connecting the trachea to the ambient atmosphere. The filter comprises a bib having a cutout neck with a border extended by one or more attachment strips adapted to form with the border a closed loop around the neck of the person by complementary joining elements which may not be separated after being joined, so that the filter cannot be re-used.

Abstract: An artificial nose (1) comprising a housing (20) mounted around the surgical opening (3) by a base ring (10) with a two-sided adhesive (15) containing a hydrophilic filtering disc (40) which forms an alternate heat and moisture exchanger between the exhaled and inhaled air. A grid (30) is arranged between the filter (40) and the surgical opening (3) and has a plane front surface (32) contacting the filter, and a convex rear surface (31) with calibrated through-passages. The distance between the front surface (32) and the rear surface (31) ensures, together with the calibre of the through-passages, that mucus ejected from the trachea is essentially unable to reach the filter.

Abstract: A pneumatic jack for electric welding comprises a cylinder which houses a piston the connecting rod of which is connectable with an electrode. The piston rod is movable between a retracted and an extended position and at the closed end of the cylinder an electric switch is located in a recess and is embedded in electrically insulating material. The switch is provided with an operating rod which extends into a passage effecting communication between the bottom of the recess and the interior of the cylinder and which operates the switch when the piston in the cylinder is in the retracted position thereof.