Pump for regenerating a decalcifying device of a dishwashing machine

A pump for bringing about a flow of regenerating brine in a chamber containing substances with water-softening properties of a decalcifying device of a dishwashing machine, comprising:

• a body (10) in which a brine inflow conduit (16) provided with a one-way valve (18) and a brine outflow conduit (12) provided with a one-way valve (14) are defined,
• a solenoid (20) having a longitudinal axis (24) and arranged within said body (10), and
• a core controlled by said solenoid (20), mobile along said longitudinal axis (24), provided with return elastic means and having an upper end associated to said body (10) and a lower end connected to a center portion of a membrane (44), whose peripheral portion is fixed to said body (10),
• wherein said core has a part of plastics material which is associated to the body (10) and to which a member of magnetic material is assembled,
• wherein said outflow conduit (12) has an initial portion (34) coaxial with said longitudinal axis (24) so that, when the pump is not active, the mouth of said initial portion (34) is closed by said center portion of the membrane (44) which ensures the water-tightness in both directions between said inflow and outflow conduits (16, 12), and
• wherein said body (10) comprises a monolithic hollow case (20) which delimits an inner cavity, within which said solenoid (22) is housed and which has an upper wall (26) having a through passage (38) acting as upper guide of the movement of said core protruding outside said inner cavity,
• wherein said core is formed by a bar (30) of plastics material, whose lower portion is surrounded by a sleeve (32) of magnetic material, and
• wherein said return elastic means comprises a helical spring (46) coaxially arranged around the bar (30) of the core between the upper end of said sleeve (32) and a lower surface of the upper wall (26) of the hollow case (20),
• wherein the bar (30) has an upper end within said through passage (38) of said hollow case (20), so that said spring (46) is entirely within said inner cavity and around said bar (30).