# US 2020/0340684 A1 · Circulation pump assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0340684 A1 - Document ID: US20200340684A1 - Status: Published application - Kind: A1 - Application number: 16/635,787 - Filed: 2018-08-02 - Published: 2020-10-29 - Earliest claimed: 2017-08-03 - Assignees: Grundfos Holding A/S - Applicants: Grundfos Holding A/S - Inventors: Thomas BLAD; Christian BLAD - Web page: https://patentgrep.com/patent/US20200340684A1 ## CPC - F24D 3/02: with forced circulation, e.g. by pumps - F04D 1/006: {double suction pumps} - F04D 13/14: the pumps being all of centrifugal type {(deviation valves F04D15/0016)} - F04D 15/0016: {mixing-reversing- or deviation valves} - F04D 15/0022: {throttling valves or valves varying the pump inlet opening or the outlet opening} - F04D 15/0066: {by changing the speed, e.g. of the driving engine} - F04D 29/4293: {Details of fluid inlet or outlet} - F24D 3/105: {pumps combined with multiple way valves} - F24D 2220/0207: Pumps - F24D 2220/0271: Valves - F24D 2220/042: Temperature sensors - Y10T 137/85954: Closed circulating system - Y10T 137/86163: Parallel - F24D: DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR (using steam or condensate extracted or exhausted from steam engine plants for heating purposes F01K17/02) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A circulation pump assembly includes a first inlet (84), an outlet (80), an electric drive motor (30) and at least one impeller (68; 100) driven by the drive motor (30). The circulation pump assembly has at least one first flow path (26; 48) positioned in a connection between the first inlet (84) and the outlet (80) for increasing the pressure of a fluid. The circulation pump assembly has a second inlet (86). The at least one impeller (68; 100) has at least one second flow path (28; 50) for increasing the pressure of a fluid, which is positioned in a connection of the second inlet (86) to the outlet (80). A heating system is provided having a circulation pump assembly of this type. ## Claims ### Claim 1 A circulation pump assembly vi comprising: a first inlet; a second inlet; an outlet; an electrical drive motor; an impeller arrangement which is driven by the drive motor; and which comprises at least one first flow path for increasing a pressure of a fluid and which is situated in a connection between the first inlet and the outlet and the impeller arrangement comprises at least one second flow path which is for increasing a pressure of a fluid and which is situated in a connection from the second inlet to the outlet. ### Claim 2 (depends on 1) A circulation pump assembly according to claim 1, wherein the at least one first flow path and the at least one second flow path, are formed in a common impeller as said impeller arrangement, or are formed in at least two impellers as said impeller arrangement, which two impellers are arranged rotationally fixed to one another. ### Claim 3 (depends on 1) A circulation pump assembly according to claim 1, wherein the at least one second flow path is formed by a section of the at least one first flow path. ### Claim 4 (depends on 1) A circulation pump assembly according to claim 1, wherein: the impeller arrangement, comprises a suction port, as a first inlet opening, departing from which the at least one first flow path extends to an outlet side of the impeller arrangement; and the impeller arrangement comprises at least one second inlet opening which is situated between the suction port and the outlet side in a direction of the flow through the impeller arrangement and is connected to the second inlet of the circulation pump assembly. ### Claim 5 (depends on 4) A circulation pump assembly according to claim 4, wherein: the at least one second inlet opening runs out into the at least one first flow path; and the section of the at least one first flow path forms the at least one second flow path between the at least one second inlet opening and the outlet side. ### Claim 6 (depends on 4) A circulation pump assembly according to claim 4, wherein the impeller arrangement comprises a plurality of second inlet openings. ### Claim 7 (depends on 5) A circulation pump assembly according to claim 5, wherein: several first flow paths are formed between impeller blades of the impeller arrangement; and the at least one second inlet opening runs out into each of the first flow paths between the impeller blades. ### Claim 8 (depends on 4) A circulation pump assembly according to claim 4, wherein the at least one second inlet opening is formed in a shroud which surrounds the suction port. ### Claim 9 (depends on 4) A circulation pump assembly according to claim 4, wherein the suction port is engaged with a stationary ring element having an interior, into which a flow connection from the first inlet runs out. ### Claim 10 (depends on 9) A circulation pump assembly according to claim 9, wherein: an annular space, into which a flow connection from the second inlet runs out is formed at an outer periphery of the ring element; and the at least one second inlet opening faces the annular space. ### Claim 11 (depends on 1) A circulation pump assembly according to claim 1 wherein the impeller arrangement is in sealing engagement with a part of the surrounding pump casing radially outside the at least one second inlet opening. ### Claim 12 (depends on 1) A circulation pump assembly according to claim 1 further comprising a valve arranged in a flow connection between the second inlet and the impeller arrangement, for adjusting the flow rate through the flow connection. ### Claim 13 (depends on 12) A circulation pump assembly according to claim 12, wherein the valve comprises an electrical drive for changing a valve position. ### Claim 14 (depends on 1) A circulation pump assembly according to claim 1, further comprising a control device configured to adjust a speed of the drive motor. ### Claim 15 A heating system comprising: a first circulation pump assembly comprising a first inlet, a second inlet, an outlet, an electrical drive motor, and an impeller arrangement which is driven by the drive motor and which comprises at least one first flow path for increasing a pressure of a fluid and which is situated in a connection between the first inlet and the outlet and the impeller arrangement comprises at least one second flow path which is for increasing a pressure of a fluid and which is situated in a connection from the second inlet to the outlet; and a second circulation pump assembly which is situated upstream of the second inlet of the first circulation pump assembly. ### Claim 16 (depends on 15) A heating system according to claim 15, further comprising wherein a control device configured to control the first circulation pump assembly and/or the second circulation pump assembly and/or a valve which is situated in the flow path from the second inlet to the impeller arrangement, to adjust a mixing ratio of the flows from the first inlet and the second inlet in the first circulation pump assembly. ### Claim 17 (depends on 15) A heating system according to claim 15, wherein: the at least one first flow path and the at least one second flow path are formed in a common impeller as said impeller arrangement; or the at least one first flow path and the at least one second flow path are formed in at least two impellers as said impeller arrangement, which two impellers are arranged rotationally fixed to one another. ### Claim 18 (depends on 15) A heating system according to claim 15, wherein the at least one second flow path is formed by a section of the at least one first flow path. ### Claim 19 (depends on 15) A heating system according to claim 15, wherein: the impeller arrangement comprises a suction port as a first inlet opening, departing from which the at least one first flow path extends to an outlet side of the impeller arrangement; and the impeller arrangement comprises at least one second inlet opening which is situated between the suction port and the outlet side in a direction of the flow through the impeller arrangement and is connected to the second inlet of the circulation pump assembly. ### Claim 20 (depends on 6) A circulation pump assembly according to claim 6, wherein: several first flow paths are formed between impeller blades of the impeller arrangement; and at least one of the second inlet openings runs out into each of the first flow paths between the impeller blades.