A method for determining a set of optimal operating parameters for a pumping plant that pumps a fluid medium by a set of multiple pumps connected in parallel includes: determining, from the set of pumps, a set of possible scenarios, each scenario indicating, for each pump in the set, whether the pump is running or not running; optimizing, for each scenario, a set of operating parameters including operating parameters of the pumps that are running according to the respective scenario so that all running pumps together bring a given input mass flow of the medium from a given input pressure to a given output pressure while minimizing a total power consumption of all running pumps, and assigning the found minimum power consumption and the corresponding optimal operating parameters to the respective scenario; and determining, from the set of scenarios, the scenario with a lowest power consumption.

A hydraulic system includes a circulation pump assembly (2) provided with a speed controller (4, 26), a hydraulic circuit (A, B) connected to the circulation pump assembly (2) as well as a mechanical switch device (86, 88; 120, 122; 120″, 122″) which is subjected to pressure from a fluid in the hydraulic circuit (A, B) and which can be moved into at least two different switch positions. The mechanical switch device (28; 86, 28; 120, 122) can be moved by the circulation pump assembly (2) by way of a hydraulic coupling via the fluid. The speed controller is configured to initiate a movement of the switch device (86, 88; 120, 122; 120″, 122″) by way of at least one hydraulic force acting thereon and causing a movement of the switch device (86, 88; 120,122; 120″, 122″), produced via the hydraulic circuit, via a speed adaptation of the circulation pump assembly.

A centrifugal pump assembly includes an electric drive motor (6, 8), a driven impeller (14) and a pump casing (2) which surrounds the impeller (14). A movable element (24; 24′) is arranged a valve element. A section of the valve element is movable from a released position into a bearing position, fixed on a contact surface (60), by pressure which is produced by the impeller in the pump casing. A control device (64) moves the valve element from one switching position into another switching position and reduces the speed of the drive motor. Upon pressure in the pump casing dropping such that the valve element is no longer fixed on the contact surface and the valve element has been moved into the other switching position, the control device increases the speed of the drive motor again. A method for moving a valve element is provided.

A blower for an HVAC system, the blower includes a housing with an intake and an outlet, a fan or blower wheel disposed within the housing and configured to draw air into the housing via the intake and to exhaust air from the housing through the outlet, and an adjustable cutoff plate configured to be moved between at least a first position defining a first cutoff angle and a second position defining a second cutoff angle.

A hydraulic system includes at least one circulation pump assembly (2) provided with a speed controller (4, 26), at least one hydraulic circuit (A, B) connected to the circulation pump assembly (2) as well as at least one mechanical switch device (86, 88; 120, 122) which is mechanically subjected to pressure by a fluid in the hydraulic circuit (A, B) and which can be moved into at least two different switch positions. The mechanical switch device (86, 88; 120, 122) moves by the circulation pump assembly (2) hydraulic coupling via the fluid. The speed controller is configured to initiate a movement of the switch device (86, 88; 120, 122), by at least one hydraulic force acting upon the switch device (86, 88; 120, 122) and causing a movement of the switch device (86, 88; 120; 122) via the hydraulic circuit, via a speed adaptation of the circulation pump assembly (2).

A blower for an HVAC system, the blower includes a housing with an intake and an outlet, a fan or blower wheel disposed within the housing and configured to draw air into the housing via the intake and to exhaust air from the housing through the outlet, and an adjustable cutoff plate configured to be moved between at least a first position defining a first cutoff angle and a second position defining a second cutoff angle.

A multistage pump with axial thrust optimization is disclosed includes a pump discharge nozzle and a bypass system coupled to the pump discharge nozzle. The bypass system includes a throttle valve operatively coupled to the pump discharge nozzle, and a bypass line provided at the multistage pump. The bypass line is conducts flow from the throttle valve to a clearance gap of an axial thrust balancing arrangement. The throttle valve may be actuated to adjust a balancing flow through the bypass line such that pressure at the clearance gap is adjusted to increase and decrease fluid pressure at the clearance gap to balance axial thrust at different operating states of the multistage pump.

A hybrid-driven dual pump for conveying a coolant for a combustion engine, is proposed. The dual pump comprises: a first pump assembly with a first pump impeller, a first spiral housing and a first pump shaft driven via a mechanical drive connection by a combustion engine; a second pump assembly with a second pump impeller, a second spiral housing, a second pump shaft and an electric drive; a joint pump housing enclosing the first pump assembly and the second pump assembly with a joint pump inlet and a joint pump outlet; and a flap arranged freely pivotably between an outlet of the first spiral housing and an outlet of the second spiral housing such that a direct flow connection between the first spiral housing and the second spiral housing is blocked.

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.

A pump device includes a flow path through which liquid flows, a first pump in the flow path, a second pump in the flow path, a first pump downstream flow path located downstream of the first pump in the flow path, a second pump downstream flow path located downstream of the second pump in the flow path, a connection flow path connected to the first pump downstream flow path and the second pump downstream flow path in the flow path, a first check valve provided in the first pump downstream flow path, and a second check valve provided in the second pump downstream flow path or the connection flow path.