Abstract: The system comprises a first substantially annular seat (159) provided in a first wall (155A) defined by the first mechanical element (155); and a second substantially annular seat (161 A, 161B) provided in a second wall (153A) defined by the second mechanical element (1). When the two mechanical elements are assembled the second substantially annular seat is positioned approximately at the level of the first substantially annular seat and the second wall is inside the first wall. The connection system between the mechanical elements also comprises at least one filiform element (157) forming a member for reciprocal blocking of the two mechanical elements, which is inserted in a space defined by the two opposed annular seats. Moreover, there is also provided a forcing member (173), insertable in a space defined between two opposed surfaces belonging respectively to the first and to the second mechanical element.

Abstract: The system comprises a first substantially annular seat (159) provided in a first wall (155A) defined by the first mechanical element (155); and a second substantially annular seat (161 A, 161B) provided in a second wall (153A) defined by the second mechanical element (1). When the two mechanical elements are assembled the second substantially annular seat is positioned approximately at the level of the first substantially annular seat and the second wall is inside the first wall. The connection system between the mechanical elements also comprises at least one filiform element (157) forming a member for reciprocal blocking of the two mechanical elements, which is inserted in a space defined by the two opposed annular seats. Moreover, there is also provided a forcing member (173), insertable in a space defined between two opposed surfaces belonging respectively to the first and to the second mechanical element.

Abstract: The device comprises a body (3) defining a chamber (21 A, 21 B) sliding inside which is a control piston (5), which divides said chamber into a first half-chamber (21 B) and a second half-chamber (21A). A duct (33; 37) to feed a control fluid leads into each half-chamber; the first half-chamber has an opening (11), closable with a closing element (13), which is constrained to the body (3) by constraining means comprising: a first substantially annular seat (25), provided in a wall surrounding said opening (11); a second substantially annular seat (27) provided in the closing element (13); a filiform element (23) forming a blocking member of the closing element, and housed in a space defined by the two substantially annular seats.

Abstract: An automatic device for the regeneration of a bed of ion-exchanging resins s constituted by a valve body internally provided with two communicating seats, in whose inside pistons which are caused to move by a couple of cams keyed on a motor-shaft slide. The valve body is provided with openings, alternately intercepted by the pistons, to realize different flows of the fluid. In running conditions, water passes through a tank containing a bed of ion-exchanging resins, whose regeneration takes place in counter-current with solutions of sodium salts. This operating stage and the following one of resin washing are carried out according to an automatic sequence by way of cams, which act on the piston.

Abstract: A multiple change-over valve which can be set into various positions suite for the operation of a water treatment plant. A moulded synthetic resin body defines two valve units with seats for two movable assemblies controlled by cylinder-piston systems such as to assume two positions; each of the two movable assemblies comprises at one end a cavity with lateral apertures, and in an intermediate position longitudinal passages for cooperating with various passages, including transverse passages, between the two seats, and with passages for communication with the top and bottom of a resin column. A suction feeder for the regenerating solution, in the form of a venturi tube, is fixed between the water feed and the top of the column in order to operate when the column is connected to discharge.