EP3438555A1 - Circulation pump generator - Google Patents

Abstract

The invention relates to a circulation pump assembly having a first input (84), an output (80), an electric drive motor (30) and at least one impeller (68, 100) driven by the drive motor (30), which has at least one first connection flow path (26; 48) for increasing the pressure of a liquid between the first input (84) and the outlet (80), the circulating pump unit having a second input (86) and the at least one impeller (68; 100) at least one second flow path (28; 50) for increasing the pressure of a liquid located in communication from the second inlet (86) to the outlet (80) and a heating system having such a circulation pumping unit.

Description

The invention relates to a circulating pump unit and a heating system with such a circulating pump unit.

In heating system circulating pumps are used to circulate a liquid heat carrier or a heating medium, in particular water through the heating system. When heating circuits are used in heating systems, which require different flow temperatures, it is common to provide mixers, which can reduce the flow temperature for certain heating circuits, such as heating circuits of a floor heating. Such mixers are often used in combination with Kompaktheizkesseln, which in addition to a heat source, such as a boiler with primary heat exchanger, also already have a circulating pump unit for circulating the heat carrier through the heating system. This circulating pump unit provides a residual head which is adapted to be sufficient for a conventional heating circuit with radiators with thermostatic valves. For a further heating circuit with reduced flow temperature then a second circulating pump unit is usually used, which is arranged downstream of a mixing valve, via which the heated heat carrier from the boiler is injected into the heating circuit with lower flow temperature. It is necessary in the mixing valve or an upstream valve to reduce the provided by the circulating pump unit in the boiler form to the pressure level at the input side of the circulating pump unit in the second heating circuit. Ie. the Residual head provided by the circulating pump unit in the boiler is destroyed and energy loss occurs.

In view of this problem, it is an object of the invention to improve a heating system in such a way that the energy losses can be minimized in a mixer. This object is achieved by a circulating pump unit having the features specified in claim 1 and by a heating system with the features specified in claim 15. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

The Umwälzpumpenaggregat invention is provided in particular as Heizungsumwälzpumpenaggregat for use in a heating system, which means heating system in the context of this invention, an air conditioner, which is not the heating but cooling. Quite generally, the circulating pump unit according to the invention can be used for circulating a liquid heat carrier or heating medium for tempering a building or a plant.

The circulating pump unit according to the invention has a first input, ie a first suction inlet and an outlet. The output is a pressure outlet through which liquid exits the circulating pump unit. Furthermore, the circulating pump unit has an electric drive motor which rotatably drives at least one impeller provided in the circulating pump unit. Ie. The circulating pump unit is a centrifugal pump unit. The electric drive motor is particularly preferably designed as a wet-running electric drive motor, ie as a motor with a split tube or containment shell between the rotor and the stator. The at least one impeller is in the circulating pump unit in a connection or flow connection between the first input and the output. The impeller has at least one flow path in this flow connection and serves to increase the pressure of a liquid. So the impeller can be a liquid, eg. As a liquid heating medium, promote from the first input to the output and increase the pressure of the liquid between the input and output. The at least one flow path through the impeller can be formed for example by conventional channels between impeller blades.

According to the invention, the circulating pump unit has a second input, wherein in the circulating pump unit a second flow connection is formed from this second input to the outlet. The second input thus forms a second suction inlet or suction connection, it being possible for a different pressure level to prevail at the second inlet than at the first inlet during operation of the circulating pump assembly. The at least one impeller further comprises at least a second flow path with pressure increase of a liquid such as a liquid heating medium, said second flow path is in the described flow connection between the second input and the output. This means that the circulation pump assembly according to the invention in the at least one impeller has two separate flow paths, via which an increase in pressure can be achieved. This configuration allows liquids such. B. two flows of a liquid heating medium from the two inputs, which have at the two inputs a different input or form, to increase the same final pressure at the output. Ie. the at least one impeller with the two flow paths is designed so that it generates two different pressure differences during its rotation.

This embodiment of the invention makes it possible to use the circulation pump unit in a heating circuit with a mixer and the second input of Umwälzpumpenaggregates liquid with a pre-pressure i. to supply a residual conveying height. This form can be provided for example by a circulation pump in a boiler or a compact heating system. The mixing point of the mixer is then located in the described Umwälzpumpenaggregat in this arrangement and it is no longer necessary to reduce the form or the residual head on the input side of the mixer to the same suction pressure on the suction side of Umwälzpumpenaggregates in the over the mixer to be supplied to the heating circuit to reach. On the contrary, the circulatory pump unit according to the invention can be supplied with fluids at two different pressure levels. At the first input, the liquid to be circulated in the heating circuit to be supplied is supplied, while via the second input the liquid to be admixed is admixed with a higher pressure level. The circulating pump unit according to the invention thus makes it possible to reduce the energy losses during operation of a mixer. As underfloor heating usually has the largest share in modern heating systems, energy savings in the area of the circulating pump units of up to 30% can be achieved in this way

Preferably, the at least one first flow path and the at least one second flow path are arranged in a common impeller. Ie. upon rotation of the impeller with the two flow paths, a pressure increase of the liquid flowing through these flow paths takes place via both flow paths. Alternatively, it is possible to use two non-rotatably arranged wheels, which rotate together. These may be integrally formed with each other or rotatably connected to each other in any other suitable manner. For example, an impeller with two blade rings Use find, wherein a first blade ring, the first flow paths and a second blade ring defines the second flow paths. Such an impeller may be formed so that the inlets or inlets for the two flow paths are located on the same axial side, viewed in the direction of the axis of rotation, or else against each other in the axial direction opposite sides. Even when using two wheels, these could be arranged so that the inlet sides or suction openings are directed opposite. Such an arrangement has the advantage that the axial forces occurring at least partially cancel.

According to a further preferred embodiment of the invention, it is possible for the at least one second flow path to be formed by a section of the at least one first flow path. In this case, the first flow path then has a first section, in which only the liquid flowing through the first flow path experiences an increase in pressure. The second inlet opens into a second section of the first flow path, in which then both the liquid which is supplied from the second input and the liquid emerging from the first section of the first flow path experience an increase in pressure. Ie. In the second flow path, both the fluid flow from the first inlet and the fluid flow from the second inlet experience an increase in pressure. When liquid at a pre-pressure is supplied at the second inlet, this has the advantage that in the first section of the first flow path, the liquid supplied via the first inlet of lower initial pressure experiences a first pressure increase, so that at the point at which the flow out opens the second input in the first flow path, the liquids from the first and the second input have a substantially equal pressure level.

More preferably, the at least one impeller has a suction mouth as the first inlet opening, starting from which the at least one first flow path extends to an outlet side of the impeller. The suction mouth as the first inlet opening communicates with the first inlet of the circulating pump unit and the outlet side of the impeller communicates with the outlet of the circulating pump unit. The impeller preferably has at least one second inlet opening, which is located in the direction of the flow through the impeller between said suction mouth and the outlet side. This at least one second inlet opening is connected to the second input of the circulating pump unit. Thus, a liquid flow with a higher pressure level can be introduced into the impeller via the second inlet opening at a position at which the liquid in the impeller, which is supplied through the suction mouth, has already experienced a certain pressure increase. When using this Umwälzpumpenaggregates in a mixer or as a mixer thus the mixing point of the two flows is in the impeller. Thus, two liquid flows with different pre-pressure can be mixed at a mixing point with essentially the same pressure level, without the higher pressure in one of the two supplied liquid flows having to be reduced first. As a result, the energy loss can be minimized.

The second inlet opening preferably opens into a first flow path, the section of the at least one first flow path between the at least one second inlet opening and the outlet side simultaneously forming the at least one second flow path. Ie. the second flow path forms a common flow path through which both the liquid flow from the first inlet and the liquid flow are directed from the second inlet, wherein the liquid flow from the first input of the circulation pump unit in a first portion of the first flow path upstream of the at least one second inlet opening has already experienced a pressure increase independent of the flow from the second input.

Particularly preferably, the impeller has a plurality of second inlet openings. As a result, the flow cross-section can be increased and thus the hydraulic resistance in the second flow path can be minimized.

Preferably, a plurality of first flow paths are formed between impeller blades of the at least one impeller and it opens into each of the first flow paths between the impeller blades at least a second inlet opening. The sections of the first flow paths between the suction mouth and the second inlet openings then form the described first flow paths, through which only the liquid supplied through the first inlet is conveyed. The second sections of the first flow paths downstream of the second inlet openings form with these a second flow path through which the liquid which is supplied through the second inlet is also conveyed. By arranging second inlet openings in each of the first flow paths, a maximum flow cross-section is provided for the second flow paths in the impeller.

More preferably, the at least one second inlet opening is formed in a cover disc surrounding the suction mouth. Ie. the impeller is designed as a closed impeller, which has a cover plate which closes the flow paths between the impeller blades in the circumference of the centrally arranged suction mouth. The suction mouth forms the first inlet opening for the first flow paths. The second inlet openings are formed as holes or gaps in the cover plate, which in these flow paths between the impeller blades open, so that the flow paths form radially on the outside of the second inlet openings, the second flow paths as described above.

The suction mouth of the at least one impeller is preferably in engagement with a stationary ring element, in the interior of which a flow connection opens from the first inlet. Thus, a flow connection is made from the first inlet into the interior of the impeller and into the first flow paths of the impeller. The ring member is further preferably in substantially sealing engagement with the suction mouth, d. H. a suction mouth is formed between the suction mouth and the ring element in order to reduce or avoid leaks in this area.

Further preferably, an annular space is formed on the outer circumference of the ring element described in which a flow connection opens from the second inlet, wherein the at least one second inlet opening of the impeller faces this annular space. In this embodiment, the annular element thus forms a partition wall between the first and the second flow connection, wherein the flow connection from the first input on the inside of the ring wall and the flow connection from the second input on the outside of the ring element to the impeller extends.

According to a further preferred embodiment of the invention, the impeller is radially outside the at least one second inlet opening in sealing engagement with a part of a surrounding pump housing. This sealing engagement forms a seal between suction and pressure side of the impeller, so that the outlet side of the impeller is sealed against the flow connection to the at least one second inlet opening.

According to a particular embodiment of the invention may be arranged at least in the flow connection between the second input and the at least one impeller, a valve for adjusting the flow through this flow connection. This valve can form a mixing valve, via which the amount of liquid supplied from the second input can be regulated, for example, to be able to regulate the temperature of the mixed flow at the outlet of Umwälzpumpenaggregates. For this purpose, the valve may preferably have an electric drive for changing the valve position, wherein the electric drive is preferably a stepping motor. The valve can then be controlled by a control device, which controls the valve position, for example, as a function of temperature as a function of the temperature at the outlet side of the circulating pump unit, d. H. as a function of the temperature of the mixed flow. This creates a mixer with temperature control. However, it can also be arranged in one or both flow connections manually operated flow control valves to z. B. to be able to make a default of the flow rates.

Particularly preferably, the circulating pump unit has a control device which is designed to set the rotational speed of the drive motor. By way of example, the control device can be designed such that it performs a pressure and / or flow control in order to maintain the pressure and / or flow in the range of predetermined setpoint values. Alternatively, a temperature-dependent speed control is possible, in which the rotational speed is set in dependence on a temperature signal so that a temperature value is maintained in the range of predetermined target values. For example, by speed control or speed change of the circulating pump unit, the temperature on the output side of the circulating pump unit, ie be regulated at the output or in the liquid flow flowing through the outlet.

In addition to the Umwälzpumpenaggregat described above, the subject of the invention is also a heating system with such a circulating pump unit, wherein the Umwälzpumpenaggregat described above forms a first Umwälzpumpenaggregat in the heating system. The heating system according to the invention also has a second circulating pump unit, which is located upstream of the second input of the first pump unit. Thus, the second circulating pump unit leads to the inlet of the first pump unit, a liquid flow with a pre-pressure, which is generated by the second circulating pump unit to. The second circulating pump unit is preferably a centrifugal pump unit, which is adjustable in its speed via a control device. This centrifugal pump assembly also preferably has an electric drive motor, which can be further preferably designed as a wet-running drive motor. The admission pressure or flow can be adjusted or regulated via the speed adjustment. The speed control of the second circulation pump unit is preferably carried out such that the flow rate and / or the pressure is maintained in the range of desired predetermined setpoint values or follows a predetermined characteristic curve. Both the first circulating pump unit and the second circulating pump unit can be designed such that they have a frequency converter for speed control.

Further preferably, a control device is provided in the heating system according to the invention, which is designed such that it controls the first circulating pump unit and / or the second circulating pump unit and / or a valve located in the flow path from the second input to the at least one impeller to set a mixing ratio of the liquid flows from the first input and the second input in the first circulation pump unit. The speed control is preferably temperature-dependent. Ie. the control device is preferably connected to at least one temperature sensor and controls the rotational speeds of the circulating pump unit or circulating pump units so that the temperature detected by the temperature sensor is maintained at a desired desired value or approximated to a desired setpoint. The temperature sensor is preferably arranged on the output side of the first circulating pump unit, so that it detects the temperature of the mixed liquid flow flowing through the outlet of the first circulating pump unit. If the control device varies the rotational speed of the second circulating pump assembly, then the amount of liquid supplied to the second input can be changed. The same can be accomplished by adjusting a valve upstream of the second inlet of the first recirculation pump assembly. By changing the speed of the first circulating pump unit, it is also possible to change the mixing ratio when the flow and / or pressure ratio of the flows through the first and the second flow path changes depending on the speed. This can be achieved by appropriate geometrical configuration of the first flow path and the second flow path, in particular if the first and the second flow path end, for example, on different outer diameters of the impeller. Thus, different pressure increases are achieved at the same speed. Furthermore, changes in the pressure ratio can be achieved in that the liquid is supplied to the second input with a, preferably constant, admission pressure. When the flow connection from the second input opens into a first flow path of the impeller, as described above, is changed in speed change, the pressure at the orifice point in the interior of the impeller, so that by the change the pressure conditions in the two flow paths, the mixing ratio is changed in the interior of the impeller.

Fig. 1

einen hydraulischer Schaltplan einer Heizungsanlage gemäß dem Stand der Technik,

Fig. 2

einen hydraulischen Schaltplan eines Heizungssystems gemäß einer ersten Ausführungsform der Erfindung,

Fig. 3

einen hydraulischen Schaltplan eines Heizungssystems gemäß einer zweiten Ausführungsform der Erfindung,

Fig. 4

einen hydraulischen Schaltplan eines Heizungssystems gemäß einer dritten Ausführungsform der Erfindung,

Fig. 5

einen hydraulischen Schaltplan eines Heizungssystems entsprechend dem Ausführungsbeispiel gemäß Fig. 3 mit einem Doppellaufrad,

Fig. 6

Explosionsansicht eines Umwälzpumpenaggregates mit einer Mischeinrichtung entsprechend dem Heizungssystem gemäß Fig. 2, 3 und 5,

Fig. 7

eine Schnittansicht des Umwälzpumpenaggregates gemäß Fig. 6 entlang seiner Längsachse x,

Fig. 8

eine Draufsicht auf die Rückseite des Umwälzpumpenaggregates gemäß Figuren 6 und 7,

Fig. 9

eine teilweise geschnittene Ansicht der Rückseite des Umwälzpumpenaggregates gemäß Fig. 6 bis 8,

Fig. 10

eine Explosionsansicht eines Umwälzpumpenaggregates mit einer Mischeinrichtung entsprechend dem Ausführungsbeispiel gemäß Fig. 4,

Fig. 11

eine Schnittansicht des Umwälzpumpenaggregates gemäß Fig. 10 entlang seiner Längsachse X,

Fig. 12

eine Draufsicht auf die Rückseite des Umwälzpumpenaggregates gemäß Fig. 9 und 10,

Fig. 13

den Druckverlauf über der Drehzahl für das Ausführungsbeispiel eines Heizungssystems gemäß Fig. 2,

Fig. 14

den Druckverlauf über der Drehzahl für ein Ausführungsbeispiel eines Heizungssystems gemäß Fig. 3 und

Fig. 15

den Druckverlauf über der Drehzahl für ein Ausführungsbeispiel eines Heizungssystems gemäß Fig. 4.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

Fig. 1

a hydraulic circuit diagram of a heating system according to the prior art,

Fig. 2

a hydraulic circuit diagram of a heating system according to a first embodiment of the invention,

Fig. 3

a hydraulic circuit diagram of a heating system according to a second embodiment of the invention,

Fig. 4

a hydraulic circuit diagram of a heating system according to a third embodiment of the invention,

Fig. 5

a hydraulic circuit diagram of a heating system according to the embodiment according to Fig. 3 with a double impeller,

Fig. 6

Exploded view of a circulating pump unit with a mixing device according to the heating system according to Fig. 2 . 3 and 5 .

Fig. 7

a sectional view of the circulating pump unit according to Fig. 6 along its longitudinal axis x,

Fig. 8

a plan view of the back of Umwälzpumpenaggregates according FIGS. 6 and 7 .

Fig. 9

a partially sectioned view of the back of Umwälzpumpenaggregates according to Fig. 6 to 8 .

Fig. 10

an exploded view of a circulating pump unit with a mixing device according to the embodiment according to Fig. 4 .

Fig. 11

a sectional view of the circulating pump unit according to Fig. 10 along its longitudinal axis X,

Fig. 12

a plan view of the back of Umwälzpumpenaggregates according Fig. 9 and 10 .

Fig. 13

the pressure curve over the speed for the embodiment of a heating system according to Fig. 2 .

Fig. 14

the pressure curve over the speed for an embodiment of a heating system according to Fig. 3 and

Fig. 15

the pressure curve over the speed for an embodiment of a heating system according to Fig. 4 ,

Fig. 1 schematically shows a conventional heating circuit for a floor heating 2, ie a heating circuit according to the prior art. The heat source is a boiler 4, for example, a gas boiler with an integrated circulation pump 6. Such combinations are known, for example, as a compact heating systems on the market. For the underfloor heating circuit 2, a further circulating pump unit 8 with an impeller 10 and an electric drive motor 12 is provided. Since the boiler 4 provides a too high flow temperature for the underfloor heating 2, a mixing device is provided here, which has a mixing point 14 which is located on the suction side of the impeller 10. Furthermore, at the mixing point or outlet point 14, a feed line 18, via which the water or heating medium heated by the heating boiler 4 flows and at the mixing point 14 by the circulating pump unit 6, opens Pressure is injected. To regulate the mixing ratio, two flow regulating valves R _hot and R _{cold are} provided in this embodiment. The regulating valve R _hot is arranged in the supply line 18 and the regulating valve R _cold in the return line 16. The valves can for example be controlled by a control device via an electric drive. Preferably, the regulating valves R _hot and R _{cold can} be coupled so that always opens one of the valves to change the flow and at the same time the other valve is closed by the same degree. Instead of two flow regulating valves R, a 3-way valve may be used, which has a valve element which simultaneously closes the return line 16 by its movement and opens the supply line 18 or vice versa. The circulating pump unit 6 can also supply a further heating circuit, not shown here, which is operated directly with the flow temperature generated by the boiler. Both the circulating pump unit 6 and the circulating pump unit 8 may have a conventional pressure or flow control. In the known system, it is disadvantageous that the flow regulating valves R are required for adjusting the mixing ratio and must be provided with a corresponding drive, for example a motor-driven or thermostatically actuated drive. The flow regulating valves R are controlled so that a desired flow temperature for the underfloor heating 2 is achieved downstream of the mixing point 14. Another disadvantage in this system is that the pressure generated by the circulating pump unit 6 must be reduced via the flow regulating valve R _hot to the suction side Pressure of the impeller 10 at the mixing point 14 to achieve. Thus, an energy loss occurs in the system, which can be avoided with the solution according to the invention described below.

In the case of the three examples of solutions according to the invention which are described schematically in FIG Fig. 2 to 4 are shown, the mixing ratio to achieve a desired flow temperature for the underfloor heating 2 is achieved solely by a speed control of Umwälzpumpenaggregates. This has two flow paths which hydraulically influence each other so that by speed change, the hydraulic resistance in at least one of the flow paths can be changed to change the mixing ratio, as will be described below.

Fig. 2 shows a first embodiment of the invention. In this turn, a boiler 4 for heating a liquid heating medium, that is provided a liquid heat carrier such as water. At this boiler 4, a circulating pump unit 6 is further arranged, which could also be integrated into the boiler 4, as it is based on Fig. 1 was explained. Furthermore, a floor heating 2 or a Fußbodenheizkreis 2 is provided, which has a return, which is connected to one side to the input side of the boiler 4 and the other via a return line 16 to a mixing point 20th leads, at which also the flow line 18 opens. The mixing or orifice point 20 is part of a mixing device 22 and further of a circulation pump assembly 24. The mixing device 22 and the circulation pump unit 24 may form an integrated unit, so that the mixing device 22 is part of the circulating pump unit 24 or the circulation pump unit 24 is part of the mixing device 22 , In particular, the mixing point 20 may be as follows will be described, lie directly in the pump housing or in an impeller of Umwälzpumpenaggregates 24.

In the embodiment according to Fig. 2 For example, the circulation pump unit 24 is formed as a double pump with two impellers 26 and 28. The wheels 26 and 28 are driven by a common drive motor 30. The wheels 26 and 28 may be formed as separate wheels or as an integrated impeller with two blade assemblies or flow paths. The first impeller 26 forms a first flow path and is in a first flow connection in the mixing device from the return line 16 to the mixing point 20. The second impeller 28 forms a second flow path and is in a second flow connection between the flow line 18 and the mixing point 20. Der Mixing point 20 is thus at the pressure side of the two wheels 26 and 28, that is, according to the invention, the two heating medium streams are mixed together after the pressure increase.

The drive motor 30 is controlled by a control device 34, which is used for speed control or speed control of the drive motor 30 and is designed so that it can change the rotational speed of the drive motor 30. For this purpose, the control device 34 has a speed controller, in particular using a frequency converter. The control device 34 may be integrated directly into the drive motor 30 or be arranged in an electronics housing directly on the drive motor and in particular on the motor housing. The control device 34 is further connected to a temperature sensor 36 and communicates with a temperature sensor 36. The temperature sensor 36 is located downstream of the mixing point 20 on or in the flow line 38, which connects the mixing point 20 with the floor heating 2. In this case, the temperature sensor 36 in the mixing device 22 and the circulating pump unit 24 be integrated. The connection of the temperature sensor 36 to the controller 34 may be provided in any suitable manner, for example, wired or wireless. A wireless connection can be realized, for example, via a radio link such as Bluetooth or W-LAN.

The temperature sensor 36 transmits a temperature value of the heating medium downstream of the mixing point 20 to the control device 34 so that it can perform a temperature control. According to the invention, the drive motor 30 and thus the circulating pump unit 34 are not dependent on pressure or flow, but temperature-dependent. Ie. the controller 34 adjusts the rotational speed of the drive motor 30 so that a desired temperature of the heating medium downstream of the mixing point 20 is achieved. The desired temperature is predetermined by a set temperature value, which may be fixed, which may be manually adjustable, or which may also be predetermined externally by a heating curve, which is stored in the control device 34 or a higher-level control. The controller 34 varies the rotational speed of the drive motor 30, whereby as described below, the mixing ratio of the heating medium streams mixed at the mixing point 20 changes, so that the temperature changes downstream of the mixing point 20. This temperature is detected by the temperature sensor 36, so that the control device 34 can perform a temperature control by speed variation of the drive motor 30 to approximate the temperature value downstream of the mixing point 20 to the temperature setpoint value.

The variation of the mixing ratio at the mixing point 20 about the speed change will be described in more detail with reference to FIG Fig. 13 explained. In Fig. 13 is the delivery height H, ie the pressure applied over the rotational speed n of the drive motor 30. Im in Fig. 2 There are three examples Differential pressure values ΔP _pre , ΔP _hot and ΔP _cold . The differential pressure ΔP _pre is generated by the circulating pump unit 6 and can not be influenced by the mixing device 22 in this case, so that it is in Fig. 13 is shown as a constant, ie independent of the rotational speed of the drive motor 30 form. The impeller 26 of Umwälzpumpenaggregates 24 generates for the return of the underfloor heating 2 a differential pressure .DELTA.P _cold and the impeller 28 generates for the flow from the supply line 18, a differential pressure .DELTA.P _hot . As in Fig. 13 can be seen, the wheels 26 and 28 are formed differently, so they have different pressure gradients, ie different speed-dependent pressure gradients. The pressure curve for the impeller 28 is less steep than the pressure curve of the impeller 26. This can be achieved, for example, that the impeller 26 has a larger outer diameter. In addition, for the heated heating medium supplied through the flow line 18, the differential pressures ΔP _pre and ΔP _{hot are added} , so that the pressure waveform ΔP _hot is shifted upward by a constant value in the graph. This ensures that the pressure curve curves .DELTA.P _hot and .DELTA.P _cold intersect at a point 39. Above and below the point of intersection of these curves are mixing areas 40 for the mixed liquid. At a speed n below the intersection 39 of the two pressure curves, the output pressure of the impeller 28 is higher than that of the impeller 26, so that the output pressure of the impeller 28 acts in the flow path through the impeller 26 at the mixing point 20 as a back pressure and hydraulic resistance and in this Operating state, the flow through the first flow path through the impeller 26 is reduced and more heated heating medium is mixed in order to achieve a higher temperature in the flow 38 to the underfloor 2. When the speed is increased, above the intersection 39 of the two pressure curves, the output pressure of the impeller 26 is higher than that of the impeller 28, so that in the second flow path through the impeller 28 is a hydraulic Resistance in the form of a back pressure at the mixing point 20 is generated and the flow through the second flow path is reduced, whereby less heated heating medium is supplied to the mixing point 20 and the temperature can be reduced on the output side of the mixing point 20.

Fig. 3 shows a further variant of a mixing device according to the invention or a heating system according to the invention, which differs from the heating system according to Fig. 2 differ in that no circulating pump unit 6 is provided in the flow 18. Ie. the heated heating medium is supplied via the supply line 18 without form the Umwälzpumpenaggregat 24. This results in the in Fig. 14 shown pressure curve curves. In Fig. 14 is in turn the delivery height H, ie the pressure applied over the rotational speed n of the drive motor 30. The pressure curve curves ΔP _cold and ΔP _hot correspond to the pressure curve _curves , which in Fig. 13 are shown. All that is missing is the constant admission pressure ΔP _pre , so that the pressure curve ΔP _{hot is} not shifted upward in the diagram, but rather how the pressure curve ΔP _cold begins at the zero point. However, both curves have a different pitch, which in turn, as described above by different impeller diameter of the wheels 26 and 28 is achieved. The fact that the differential pressure at the wheels 26 and 28 changes differently with speed change, the hydraulic resistances change, resulting in a mixing region 42 between the two pressure curves with a resulting differential pressure. The higher output pressure ΔP _{cold of} the impeller 26 acts as a hydraulic resistance in the second flow path through the impeller 28 at the mixing point 20. The hydraulic resistance results from the pressure difference between the output pressures of the impellers 26 and 28 at the mixing point 20. As in FIG Fig. 14 recognizable, this pressure difference between the pressure curve curves ΔP _cold and ΔP _hot (the mixing region 42) is speed-dependent. D. H. Also, the hydraulic resistance, which acts in the flow path through the impeller 28 can be varied by changing the speed, so that the flow through the impeller 28 and thus the flow of heated heating medium can be changed. Even so, a change in the temperature on the output side of the mixing point 20 and thus a temperature control by changing the speed of the rotational speed n of the drive motor 30 is possible.

Fig. 5 shows an embodiment which is a variant of in Fig. 2 illustrated embodiment represents. There are the two wheels 26 and 28 are formed in the form of a double impeller. Ie. the impeller 26 is formed by a first blade ring and the impeller 28 by a second blade ring of the same impeller. The variation of the mixing ratio at the mixing point 20 by changing the rotational speed n of the drive motor 30 takes place in the same way as with reference to FIG Fig. 3 and 13 described. In this embodiment, a flow regulating valve R _hot and in the return line 16, a flow regulating valve R _cold are additionally provided upstream of the wheels 26 and 28 in the flow line 18. These are manually adjustable valves, with which a default can be made before the described speed control is performed. The default setting is preferably carried out in such a way that initially the rotational speed of the drive motor 30 is set so that a sufficient flow is achieved by the bottom floor 2. Ie. it is the rotational speed of the wheels 26 and 28 initially adjusted so that a matched to the system, ie the hydraulic resistance of the system differential pressure is generated. Subsequently, the manual flow control valves R _hot and R _cold are adjusted so that at the given speed at the temperature sensor 36, a desired temperature setpoint value is reached. This temperature setpoint value can be, for example, a temperature setpoint value which is preset by a heating curve at the current outside temperature. By manual presetting, a balance between different hydraulic resistances in the flow line 18 and the return line 16 is achieved. After this default temperature control can then be performed by speed control using the controller 34, with only small speed changes are required for temperature adjustment, as is apparent from the diagram in Fig. 13 results. Such valves for presetting can also be used in the other described embodiments.

Fig. 4 showed a third variant of a heating system with a mixing device according to the invention. Also in this heating system, a boiler 4 is provided with a downstream circulating pump unit 6. Furthermore, a floor heating 2 or a floor heating circuit 2 to be supplied is provided. Again, a mixing device 44 is present in which a heating medium flow from a supply line 18 which extends from the boiler 4 is mixed with a heating medium flow from a return line 16 from the return of the floor heating 2. In this exemplary embodiment, the mixing device 44 in turn has a circulation pump unit 46 with an electric drive motor 30. Also, this drive motor 30 is controlled in its rotational speed by a control device 34, which can be integrated directly into the drive motor 30 or arranged directly in an electronics housing on the drive motor 30. As in the preceding exemplary embodiments, the control device 34 is communicatively connected to a temperature sensor 36, which is located at a supply line 38 to the floor circuit 2 so that it detects the flow temperature of the heating medium which is supplied to the underfloor heating circuit 2. Thus, a temperature-dependent speed control can also be performed in the circulating pump unit 36 in the manner described above.

Of the embodiments described above, the embodiment differs according to Fig. 4 Although the circulatory pump unit does not have two parallel-connected impellers, but rather impeller parts 48 and 50 connected in series. The impeller parts 48 and 50 may be designed as two separate rotors which are connected to one another in a rotationally fixed manner so that they are rotationally driven via the common drive motor 30. However, the impeller parts 48, 50 are particularly preferably designed as an impeller, which has at least one second inlet opening in a radial middle area between a first central inlet opening and the outlet opening, as described in greater detail below. In this exemplary embodiment, this second inlet opening forms the mixing or orifice point 52, at which the two liquid flows or heating medium flows from the return line 16 and the feed line 18 are mixed. Via the impeller part 48, the heating medium flow from the return line 16 experiences a first pressure increase ΔP1 upstream of the mixing point 52. The heating medium flow from the supply line 18 experiences a pressure increase ΔP _pre through the circulation pump unit 6. which leaves the impeller part 48, injected. The orifice point 52 and the second impeller part 50 form a second flow path, through which the heating medium flow from the feed line 18 and further downstream of the mouth point 52 and the heating medium flow from the return line 16, which previously experienced in a first flow path in the impeller part 48, a pressure increase has, flow. In the impeller part 50, the mixed heating medium flow experiences a further pressure increase ΔP2.

Even with this configuration, the mixing ratio between the heating medium flow from the return line 16 and the heating medium flow from the flow line 18 can be changed by changing the speed become, as by means of Fig. 15 will be described in more detail. In Fig. 15 In turn, the pressure curves in the form of the delivery height H are plotted against the rotational speed n of the drive motor 30. In the diagram in Fig. 15 is the constant form pressure ΔP _pre , which is generated by the circulating pump unit 6 to recognize as a horizontal line. Furthermore, the two speed-dependent pressure curves ΔP1 and ΔP2 are shown. In this case, the pressure curve .DELTA.P2 has a steeper course than the pressure curve .DELTA.P1, ie, the pressure .DELTA.P2 rises with increasing the speed more than the pressure .DELTA.P1. Between the pressure curve ΔP1 and the pre-pressure ΔP _pre there is a mixing region 54 in which different mixing ratios can be realized. With increasing pressure ΔP1, which the heating medium flow from the return line 16 experiences in the impeller part 48, the hydraulic resistance increases in the second flow path to the impeller part 50 at the mixing point 52. It forms a back pressure at the mixing point 52, which serves as a hydraulic resistance for the Heating medium flow is used, which enters from the flow line 18 into the mixing point 52. The higher the back pressure at the mixing point 52, the lower the flow through this second flow path through the orifice point 52, ie, the smaller the heating medium flow which enters from the feed line 18 into the mixing point 52 and thus the second flow path. By exceeding the pre-pressure .DELTA.P _pre by the pressure .DELTA.P1 of the hot water flow, ie the heating medium flow from the flow line 18 is completely switched off. Thus, by changing the speed, the mixing ratio can be changed. In the second impeller part 50, the mixed heating medium flow then experiences the pressure increase to the pressure ΔP2.

This arrangement has the advantage that the pressure ΔP _pre , which is generated by the circulating pump unit 6, does not have to be reduced since the mixture of the two heating medium flows at a higher pressure level, namely at the level of the pressure .DELTA.P1 takes place. As a result, energy losses in the mixing device 44 are reduced.

The following is based on the FIGS. 6 to 12 the structural design of the mixing devices 22 and 44 described in more detail. The show FIGS. 6 to 9 a mixing device, which as a mixing device 22 in the embodiments according to Figures 2 . 3 and 5 is used. The FIGS. 10 to 12 show a mixer 44, as in the embodiment according to Fig. 4 is used.

The embodiment according to Fig. 6 to 9 shows an integrated circulation pump mixing device, ie a circulating pump unit with integrated mixing device or a mixing device with integrated circulation pump unit. The circulating pump unit has, in a known manner, an electric drive motor 30 to which an electronics housing or terminal box 56 is attached. In the electronics housing, the control device 34 is arranged in this embodiment. The electric drive motor has a stator or motor housing 58, inside which the stator 60 of the drive motor 30 is arranged. The stator 60 surrounds a gap pot or a can 62, which separates the stator space from a centrally located rotor space. In the rotor space of the rotor 64 is arranged, which may be formed for example as a permanent magnet rotor. The rotor 64 is connected via a rotor shaft 66 to the impeller 68, so that the rotor 64 rotatably drives the impeller 68 as it rotates about the rotation axis X.

The impeller 68 is formed in this embodiment as a double impeller and combines the wheels 26 and 28, as they are based on Fig. 2 and 5 has been described. The impeller 68 has a central suction mouth 70, which opens into a first blade arrangement or a first blade ring, which forms the impeller 26. So is defined by the suction port 70 and the impeller 26, a first flow path through the impeller 68. The impeller 26 is formed closed and has a front cover plate 72, which merges into a suction mouth 70 limiting collar. On the front cover plate 72, a second blade ring is arranged or formed, which forms the second impeller 28. The second impeller 28 has an annular suction port 74 on the inlet side, which annularly surrounds the suction port 70. The second suction port 74 forms a second inlet opening of the impeller 68. The impeller 28, starting from the second suction port 74, a second flow path through the impeller 68. Both the impeller 26 and the impeller 28 have circumferentially outlet openings, which in a pressure chamber 76 of a Pump housing 78 open.

The pump housing 78 is connected to the motor housing 58 in a conventional manner. The pressure chamber 76 in the interior of the pump housing 78 opens into a pressure port 80, which in accordance with in the embodiments Fig. 2 . 3 and 5 the supply line 38 would connect to the floor heating 2. Since both wheels 26 and 28 open into the pressure chamber 76, which is based on Fig. 2 . 3 and 5 described mixing point 20 exit side of the impeller 68 in the pressure chamber 76 of the pump housing 78th

The first suction mouth 70 of the impeller 68 is in the pump housing 78 with a first suction line 82, which starts at a first suction port 84, in conjunction. This first suction nozzle 84 is axially aligned with the discharge nozzle 80 along an installation axis which extends normal to the axis of rotation X. At the suction port 84 is in the embodiments according to Fig. 2 . 3 and 5 the return line 16 connected. In this embodiment, in the suction line 82, moreover, a flow regulating valve R _{cold is} disposed as shown in _FIG Fig. 5 is shown.

From the suction port 84, which forms a first input, a first flow connection through the pump housing 78 is defined via the suction line 82, the suction port 70, the first impeller 26, the pressure chamber 76 and the discharge port 80. The pump housing 78 also has a second suction port 86, which forms a second input. The second suction nozzle is connected in the interior of the pump housing 78 via a connecting channel 88 with an annular space 90 on the suction side of the impeller 68. The annular space 90 surrounds a ring element 92 on the outside. The ring element 92 is inserted into the suction chamber of the pump housing 78 and engages with its annular collar with the collar surrounding the suction mouth 70, so that a sealed flow connection is created from the suction channel 82 into the suction mouth 70. Externally, the ring element 92 is surrounded by the annular space 90, so that the ring element 92 separates the flow path to the suction mouth 70 from the flow path to the second suction mouth 74. Inserted into the pump housing is also an annular sealing element 94, which abuts against the inner circumference of the pump housing 78 and sealingly comes into contact with the outer periphery of the impeller 68. In this case, the sealing element 94 in the outer peripheral region of the second suction mouth 74 with the impeller 68 in sealing contact, so that it separates the suction region on the inlet side of the suction mouth 74 of the pressure chamber 76 in the pump housing.

In the flow path from the second suction port 86 to the connecting channel 88, a check valve 96 is also arranged, which prevents a backflow of liquid into the flow line 18. At the second suction port 86, the flow line 18, as shown in the Fig. 2 . 3 and 5 shown is connected.

With the circulating pump unit 24 shown with the integrated mixing device 22 can by speed change of the drive motor 30 a temperature of the heating medium, which is supplied to the underfloor 2, can be achieved, as it is based on the Fig. 2 . 3 and 5 and 13 and 14 has been described.

Via the flow regulating valves R _cold and R _hot , as indicated by Fig. 5 described a default to be made. In this embodiment, the flow regulating valves R _cold and R _{hot are formed} as rotatable valve elements 98, which are each inserted into a cylindrical receiving space. By rotation, the valve elements 98 reach different degrees into the suction line 82 or cover the connecting channel 88, so that the free flow cross section in the first or second flow path can be changed by rotation of the corresponding valve element 98.

The 10 to 12 show an embodiment of the Umwälzpumpenaggregates 46 with the mixing device 44, as shown by Fig. 4 and 15 has been described. The mixing device 44 and the circulation pump unit 46 also represent an integrated unit. The drive motor 30 with the attached electronics housing 56 corresponds in a structure to the drive motor 30, as it is based on the Fig. 7 to 9 has been described. Also, the pump housing 78 'in its construction substantially corresponds to the above-described pump housing 78. A first difference is that the pump housing 78' has no flow control valves R _hot and R _cold , it being understood that in this second embodiment, such flow control valves R could be provided, as described above. A second difference is that the second suction port 86 'in this embodiment has an external thread. However, it should be understood that also the suction port 86 according to the preceding embodiment could be designed according to or the Saugstutzten 86 'could also have an internal thread.

In the second embodiment, an impeller 100 is connected to the rotor shaft 66. This impeller 100 has a central suction mouth 102, the peripheral edge of which is in sealing engagement with the ring member 92, so that a flow connection of the first suction port 84 is created in the impeller 100. The impeller 100 has only one blade ring, which defines a first flow path from the suction port 102, which forms a first inlet opening, to the outer periphery of the impeller 100. This first flow path opens into the pressure chamber 76, which is connected to the pressure port 80. Surrounding the ring element 92 is in turn an annular space 90, in which the connecting channel 88 opens from the second suction port 86. The impeller 100 has a front cover disk 104. In this openings 106 are formed, which form second inlet openings. These openings 106 open into the flow channels 108 between the impeller blades. In this case, the openings 106 open radially relative to the axis of rotation X seen in an area between the suction port 102 and the outer periphery of the impeller 100 in the flow channels 108. D. h. the openings 106 open into a radial middle region of the first flow path through the impeller 100. The openings 106 and the flow channels 108 form with their sections radially outside of the openings 106 form second flow paths, which the impeller part 50, as it Fig. 4 has been described corresponds. The impeller part 78 is formed by the radially inner impeller part, ie in the flow direction between the suction mouth 102 and the openings 106. The openings 106 face the annular space 90, so that heating medium can enter via the connecting channel 88 into these openings 106. The outlet side of the openings 106 is thus in the Flow channels 108 in this embodiment, the mixing point 52 according to Fig. 4 ,

The impeller 100 has on its outer circumference, ie on the outer circumference of the cover plate 104 on an axially directed collar 110 which rests on the inner circumference of the pump housing 78 'and thus seals the annular space 90 relative to the pressure chamber 76. With the in 10 to 12 shown Umwälzpumpenaggregat 46 with integrated mixing device 44, a temperature control of the Heizmediumstroms, which is supplied to the Fußbodenheizkreis 2, are performed, as they are based on the Fig. 4 and 15 has been described above.

In the case of the three solutions described by way of example according to the invention, a regulation of the temperature has been described by adjusting the mixing ratio solely by changing the speed. However, it is to be understood that such a flow temperature control could also be realized in combination with an additional valve R _hot in the flow line 18 and / or a valve R _cold in the return line 16. In this case, the valves R _hot or R _{cold may} optionally be coupled to each other or be formed together as a three-way valve. An electric drive of these valves could be controlled by a common control device 34, which also controls the speed of the drive motor 30. Thus, by controlling the valves together with the control of the rotational speed of the drive motor 30, the mixing ratio and thus the temperature in the flow line for underfloor heating can be regulated or controlled. As a result, on the one hand, a larger control range can be achieved. On the other hand, the losses can be reduced by larger valve opening degrees. For example, the speed can be increased only for a short time to mix in an increased amount of heated heating medium.

The invention has been described using the example of a heating system. It should be understood, however, that the invention may equally be used in other applications in which two streams of liquid are to be mixed. One possible application is, for example, a system for setting a service water temperature, as is customary in pressure booster pumps for service water supply, in so-called shower booster pumps.

LIST OF REFERENCE NUMBERS

2

Underfloor heating, underfloor heating circuit

4

boiler

6

circulation pump assembly

8th

circulation pump assembly

10

Wheel

12

drive motor

14

mixing point

16

Return line

18

supply line

R, R _hot , R _cold

Durchflussregulierventile

20

mixing point

22

mixing device

24

circulation pump assembly

26, 28

Impellers or arrangements of impeller blades

30

drive motor

34

control device

36

temperature sensor

38

Supply line for underfloor heating 2

39

intersection

40, 42

mixing area

44

mixing device

46

circulation pump assembly

48, 50

Impeller parts or flow paths

52

mixing point

54

mixing area

56

electronics housing

58

motor housing

60

stator

62

canned

64

rotor

66

rotor shaft

68

Wheel

70

saugmund

72

front cover disc

74

second suction mouth, second inlet opening

76

pressure port

78, 78 '

pump housing

80

pressure port

82

suction

84

suction

86

second suction nozzle

88

connecting channel

90

annulus

92

ring element

94

sealing element

96

check valve

98

valve elements

100

Wheel

102

saugmund

104

cover disc

106

Openings, second entry openings

108

flow channels

110

collar

s

flow direction

X

axis of rotation

Claims (16)

Circulation pump unit having a first input (84), an output (80), an electric drive motor (30) and at least one impeller (68; 100) driven by the drive motor (30), which at least one first, in a connection between the first input (84) and the output (80) located flow path (26; 48) for increasing the pressure of a liquid,
characterized in that
the circulation pump assembly has a second input (86) and the at least one impeller (68; 100) has at least one second flow path (28; 50) for increasing the pressure of a liquid which is in communication from the second input (86) to the output (80 ) is located. Circulating pump unit according to Claim 1, characterized in that the at least one first flow path (26; 48) and the at least one second flow path (28; 50) are formed in a common impeller (68; 100) or in at least two impellers rotatably arranged relative to one another. Circulating pump unit according to claim 1 or 2, characterized in that the at least one second flow path (50) is formed by a portion of the at least one first flow path (48). Circulating pump unit according to one of the preceding Anspürche, characterized in that
the at least one impeller (68; 100) has a suction mouth (70; 102) as the first inlet opening, from which the at least one first flow path (26; 48) leads to an exit side of the outlet Impeller (68; 100) extends, and that the impeller (68; 100) at least a second inlet opening (74; 106) which in the direction of flow through the impeller (68; 100) between the suction mouth (70; 102) and the outlet side is located and connected to the second input (86) of the circulating pump unit. Circulating pump unit according to claim 4, characterized in that the at least one second inlet opening (106) opens into the at least one first flow path (48, 50), the section (50) of the at least one first flow path between the at least one second inlet opening (106). and the exit side forms the at least one second flow path (50). Circulating pump unit according to claim 4 or 5, characterized in that the impeller (100) has a plurality of second inlet openings (106). Circulating pump unit according to claims 5 and 6, characterized in that a plurality of first flow paths (28; 108) are formed between impeller blades of the at least one impeller (100) and at least one second inlet opening (74; 106) opens into each of the first flow paths between the impeller blades. Circulating pump unit according to one of claims 4 to 7, characterized in that the at least one second inlet opening (74; 100) is formed in a cover disc (72; 104) surrounding the suction mouth (70; 102). Circulating pump unit according to one of claims 4 to 8, characterized in that the suction mouth (70; 102) is in engagement with a stationary ring element (92), in the interior of which a flow connection (82) opens from the first inlet (84). Circulating pump unit according to claim 9, characterized in that an annular space (90) is formed on the outer circumference of the ring element (92), into which a flow connection from the second inlet (86) opens, and in that the at least one second inlet opening (106) engages this annular space (90 ) is facing. Circulating pump unit according to one of the preceding claims 4 to 10, characterized in that the impeller (68; 100) is radially outside the at least one second inlet opening (106) in sealing engagement with a part of a surrounding pump housing. Circulation pump unit according to one of the preceding claims, characterized in that in a flow connection between the second input (86) and the at least one impeller (68; 100) a valve (R) for adjusting the flow through this flow connection is arranged. Circulating pump unit according to claim 12, characterized in that the valve has an electric drive for changing the valve position, wherein the electric drive is preferably a stepper motor. Circulating pump unit according to one of the preceding claims, characterized by a control device (34) which is designed to set the rotational speed of the drive motor (30). Heating system with a first circulation pump unit according to one of the preceding claims, characterized by a second circulating pump unit (6) which is located upstream of the second input (86) of the first circulating pump unit (24; 46), wherein the second circulating pump unit (6) is preferably a centrifugal pump unit which is adjustable via a control device in its speed. Heating system according to claim 15, characterized in that a control device (34) is provided, which is designed such that it the first circulating pump unit (24; 46) and / or the second circulating pump unit (6) and / or in the flow path of the second The input (86) controls the valve located at least one impeller (68; 100) to adjust a mixing ratio of the flows from the first input (84) and the second input (86) in the first circulating pump unit (24; 46).

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