A disposition of admission valves is described and of compressed air drainage for blots some formatrici, particularly blots of it shoot-spirits, in which in the unit of shot consisting of a tank of pressure and a piston of commando, to the disotto of the commando piston, a pressure room is arranged, which present at least two openings. To an opening a vent valve is connected express. The other opening is found in connection with the shot room through a channel and is covered by means of an estate element. The estate element consists of a resistant material to the abrasion, is formed like labbro and joins, in the inside of the pressure room, to this opening.