Abstract: There is described a device for reducing the delivery pressure of a combustible gas, particularly for systems supplying gas to internal combustion engines for automotive vehicles, comprising a valve seat (5) positioned in a gas flow tube (2) formed in the body (1a) of the reducer, between an inlet section (3) and an outlet section (4), a diaphragm-operated plug element (6) associated with said valve seat (5) and movable along a predetermined axial direction (X) for the purpose of opening and closing the seat (5), a spring device (9) acting on the to diaphragm to subject the latter to a predetermined resilient load, an actuator rod (11) connected for operation to the plug (6) and to the diaphragm, a pressure compensator element (12) which is fixed to the plug (6) upstream of the valve seat with respect to the direction of flow, and which is axially extensible along that direction as a result of the movement of said plug (6) relative to the valve seat (5).

Abstract: A device for controlling the supply of fuel gas in internal combustion engines (2) comprises a gas supply duct (4) and valve means provided in this duct in order to intercept the flow of fuel gas to a combustion chamber of the engine (2), in which the valve means comprise at least one electrovalve (6) controlled by a manually actuated electromagnet (7).

Abstract: A valve unit for controlling the delivery of a combustible gas through a gas path comprises a first valve seat in the gas path and a first closure means associated with the seat, a first actuator means for the control of the closure means for opening and closing of the valve seat and also motor means for the operating control of the first actuator means. The unit further comprises a second electromagnetic actuator means interposed between the closure means and the first actuator means to urge the closure means so as to close the valve seat, independently of the operating position of the first actuator means, when a predetermined condition occurs which requires the interception of the valve seat.

Abstract: A valve unit for controlling the delivery of a combustible gas through a gas path comprises a first valve seat in the gas path and a first closure means associated with the seat, a first actuator means for the control of the closure means for opening and closing of the valve seat and also motor means for the operating control of the first actuator means. The unit further comprises a second electromagnetic actuator means interposed between the closure means and the first actuator means to urge the closure means so as to close the valve seat, independently of the operating position of the first actuator means, when a predetermined condition occurs which requires the interception of the valve seat.

Abstract: The pilot burner described comprises a duct defining a gas-mixing chamber, a head mounted removably on the duct at a first end thereof and bearing at least one flame jet, and a gas-supply nozzle mounted in the duct for admitting gas to the chamber. The burner is of the type with a nozzle which is accessible through the first end of the duct after the head has been removed from the end, and the nozzle is fixed in a nozzle-holder which in turn is fixed removably in the duct by insertion in the duct through the first end.

Abstract: A process for the selective extraction of arsenic from acid solutions containing other metals comprising treating the solutions with polyhydroxybenzene derivatives in organic diluent; mono- and di- alkyl derivatives containing at least four alkyl carbon atoms of pyrocatechol and pyrogallic acid are particularly contemplated for use in the removal of arsenic from strongly acid copper-containing electrolyte solutions.

Abstract: Process for the separation of arsenic from acid aqueous solutions containing arsenic and other metals characterized in that the acid aqueous solution is placed in the contact with water-immiscible organic solvent which extracts the arsenic, the arsenic being reextracted from the organic solvent by means of a countersolvent.