Jet pump, in particular for hot-water heating systems with return-flow mixing

In a hot-water heating system,

• a low-noise water jet pump having
• a housing (7);
• a water feeder head (1) secured to the housing;
• a first line connection (5), connected to the feeder head and receiving hot water under pressure and conducting the pressurized hot water to the feeder head (1);
• a water injector nozzle (10) located in the housing, and communicating with the feeder head to provide an injector stream;
• a water receptor nozzle (13) located in the housing;
• a cylindrical water mixing tube (14) located in the housing, coaxial with the injector nozzle (10) and the receptor nozzle (13);
• a second line connection (12) to supply hot water to a heat consumer (30), formed in the housing, coaxial with and joined to the mixing tube for discharging mixed water and having a predetermined nominal diameter (ND);
• third and fourth water line connections (18, 19) extending into the interior of the housing, and having discharge openings (20, 21) positioned to direct fluid transversely with respect to the injector stream into the housing for receiving return water from the heat consumer to be mixed with the pressurized hot water, for recycling to the heat consumer and drainage of excess water;
• wherein the third line connection (18) and the fourth line connection (19) are coaxial, and positioned for communicating directly with the interior of the housing in a region surrounding the mixing tube (14),
• the axes of the discharge openings (20, 21) of the third and fourth line connections (18, 19) intersecting the mixing tube (14) and being spaced apart from the receptor nozzle (13) by a distance from the receptor nozzle (13) of about 3-4 times the predetermined nominal diameter (ND) of the second line connection.