CIRCULATION PUMP UNIT

Description

[0001] The invention relates to a circulating pump unit with an electric drive motor and a control device for speed control of the drive motor, as well as an arrangement of at least two such circulating pump units and a method for controlling at least two circulating pump units in a hydraulic circuit system.

[0002] In hydraulic circuit systems such as heating or air conditioning systems, circulation pumps are used to circulate a liquid heat transfer fluid, for example, water. It is common practice to use a central heat source, such as a boiler, from which the heat transfer fluid is pumped to different heating circuits, for example, one for underfloor heating and a second for conventional radiators. Each heating circuit contains at least one circulation pump unit. However, in such a configuration, part of the heating circuits—namely, the one through the central heat or cold source, such as the boiler—shares a common flow path. This means that the flow rate in this shared flow path depends on the pumping capacity of several units, making the regulation and control of the individual circulation pump units challenging.If a single circulation pump unit is equipped with a function for automatically adjusting its control scheme, this can lead to malfunctions when multiple parallel heating circuits are installed. This is because, when a second circulation pump unit is put into operation, the pressure drop in the circuit of the first pump unit also increases, as the pressure drop in the common part of the circuit rises due to the increased flow rate. This can cause the first pump unit to adjust its output incorrectly and undesirably.

[0003] EP 0 735 273 A1 discloses a double pump with two parallel pumps that have a common inlet and a common outlet. These pumps have a common control unit that controls the operation of the two pumps in combination or alternately. This pump cannot be used to supply two different branches of a heating system, e.g., two different areas of a building, because this double pump only has one common outlet. Further pump assemblies are known from WO 2009 / 079447 A1, JP 2015 025427 A, US 2002 / 033420 A1, and US 2010 / 300540 A1.

[0004] Against the background of this problem, the object of the invention is to improve a circulation pump unit in such a way that it avoids such mismatches when several similar circulation pump units are arranged in a connected hydraulic system.

[0005] This problem is solved by a circulating pump unit with the features specified in claim 1, by the arrangement of at least two such circulating pump units according to claim 13, and by a method for controlling at least two circulating pump units in a common hydraulic system according to claim 14. Preferred embodiments are described in the dependent claims, the following description, and the accompanying figures.

[0006] The circulating pump assembly according to the invention comprises, in a known manner, an electric drive motor and an electronic control unit for controlling and regulating the drive motor. The control unit for speed control of the drive motor is designed to control and regulate the speed of the drive motor according to a control scheme, which is preferably stored in the control unit. This means, in particular, that the control unit is designed to set and vary the speed of the drive motor according to the control scheme. The circulating pump assembly is, in particular, a centrifugal pump assembly with at least one impeller driven by the drive motor.Preferably, the drive motor can be a wet-running electric drive motor in which a rotor chamber, in which the rotor of the drive motor rotates, is separated from a stator chamber, in which the stator windings are arranged, by a canned tube or a canned housing, so that the rotor rotates in the fluid to be pumped. According to the invention, such a circulating pump unit can be designed, in particular, as a heating circulating pump unit, i.e., as a circulating pump unit for circulating a liquid heat transfer medium such as water in a heating or air conditioning system.

[0007] According to the invention, the control unit comprises a detection module or detection function configured to detect a state variable representing an operating state from a parallel flow path with a second identical circulating pump unit. The state variable to be detected is preferably a hydraulic state variable, such as a flow rate, or more preferably a quantity representing a hydraulic state. The control unit of the circulating pump unit is configured such that it can modify the control scheme according to which it controls the electric drive motor of the circulating pump unit based on a state variable detected by the detection function. That is, the circulating pump unit can detect changes in state in another circuit or branch of a hydraulic system via the detection function and adapt its own control scheme based on this state variable.In this way, hydraulic changes in state in a system caused by at least one other circulating pump unit in another, parallel branch of the hydraulic system can be taken into account and compensated for during control, so that misadjustments of the control of the first pump unit due to the commissioning or speed change of at least one second circulating pump unit are avoided.

[0008] In particular, the detection function can be configured to detect a state variable representing a flow rate caused by a second circulating pump unit. This allows the first pump unit to account for flow rate changes in a common flow path or branch of the hydraulic system caused by at least one second circulating pump unit. Pressure losses in the common branch of the system resulting from flow rate changes caused by another circulating pump unit can thus be taken into account, preventing undesirable mismatches. In a heating system, this can prevent the control unit from mistakenly interpreting an increase in pressure loss as the closing of radiator valves and consequently reducing the speed or delivery rate of the associated pump unit.If the pressure loss in the common branch is caused by an increase in the flow rate due to the commissioning of a second circulation pump unit, it is preferable to also increase the speed of the first circulation pump unit in order to compensate for this pressure loss as far as possible and to continue supplying the associated hydraulic circuit or branch with sufficient pressure. The detection function is preferably implemented as a software module in the control unit of the electric drive motor and is further preferably connected to at least one communication interface via which the state variable can be detected. This can be a communication interface that can alternatively or additionally be used for other communication functions of the control unit.

[0009] According to the invention, the detection function is configured such that it recognizes a signal, as a state variable as described above, which represents the switching on and / or off or a change in speed of at least a second circulating pump unit. The control device is configured such that the drive motor can be controlled by the control device taking this detected signal into account. That is, according to the invention, the state variable merely represents the operating state of at least a second circulating pump unit in such a way that it can be determined from the state variable whether the at least one second circulating pump unit is in operation or not, or whether a change in speed is occurring.Hydraulic changes caused by the operation of the second circulating pump unit can then be detected by the circulating pump unit in other ways, for example, via sensors located within the circulating pump unit or by evaluating electrical parameters from the drive motor to determine, for instance, the differential pressure within the circulating pump unit. If a pressure change is detected, it can then be determined, for example, using the detected state variable, whether this change results from the commissioning of a second circulating pump unit or not. If the state variable signals the commissioning or speed change of a second circulating pump unit, the control unit of the first circulating pump unit can preferably automatically determine, based on the pressure change, the flow rate of the second circulating pump unit or what adjustment of the control scheme is required for compensation.

[0010] According to another possible embodiment of the invention, the detection function for recognizing a signal can be configured in the form of at least one predetermined pattern of a hydraulic load acting on the circulation pump unit. Such functionality makes it possible to transmit the state variable hydraulically within the system, thus eliminating the need for separate communication paths for signal transmission, in particular an electrical connection, between multiple circulation pump units. For example, the circulation pump unit can be configured to generate a specific hydraulic pattern in the form of flow or pressure fluctuations during its commissioning, e.g., by being briefly switched on and off several times in succession during startup. This causes pressure or flow fluctuations in the hydraulic system, which can then be detected as a state variable by the sensors of a corresponding, identical circulation pump unit.The control unit of the circulation pump unit can thus recognize that a second circulation pump unit has been switched on, based on such pressure or flow fluctuations, which are deliberately caused when a second circulation pump unit is switched on.

[0011] According to a further preferred embodiment of the invention, the control unit has a communication interface which is connected to the sensing function in such a way that the sensing function can receive a signal via the communication interface. The communication interface can be an electrical interface or an electromagnetic interface such as a radio interface. Alternatively, other suitable signal transmission paths and associated interfaces, such as an optical interface, can also be used. If several identical circulation pump units with corresponding communication interfaces are used in a hydraulic system, they can communicate with each other via these communication interfaces and exchange the described state variables. The state variables can be transmitted and received as signals via the communication interfaces.

[0012] The control unit further includes a signal generation device configured to generate a signal representing the switching on and / or off, or a change in speed, of the drive motor. This can be either a signal output via a communication interface, as previously described, or a signal transmitted hydraulically, also as previously described. For this purpose, the drive motor can be controlled to generate a specific hydraulic pattern in the hydraulic circuit system in which the circulation pump unit is used, which can then be detected by the sensing device of a second, identical circulation pump unit.

[0013] It is understood that the circulation pump unit is designed to be used together with at least one other similar, preferably identically designed, circulation pump unit in a hydraulic circuit system, wherein each of the circulation pump units is arranged in a branch or circuit of the hydraulic circuit system and these circuits or branches lead via a common flow path or branch, such as through a boiler. In such an arrangement, each individual circulation pump unit can detect the signal generated by the signal generation device of the other or other circulation pump units as a state variable and adjust its control scheme accordingly.

[0014] The control unit preferably has a communication interface which is connected to the signal generation unit in such a way that the signal generation unit can transmit a signal or a value via the communication interface. The signal or value represents a state variable as described above. According to the above description, the communication interface can preferably be an electrical or electromagnetic interface to output an electrical signal or an electromagnetic signal, such as a radio signal, which can then be detected by a corresponding communication interface of a second circulation pump unit. The communication interface is particularly preferably designed to interact with both the signal generation unit and the detection function, so that the communication interface is bidirectional, i.e., it can communicate with both the signal generation unit and the detection unit.It can send signals and can accordingly receive signals from another circulation pump unit.

[0015] The communication interface can be particularly advantageously configured to have a relay function, enabling data received from one communication interface to be forwarded to yet another. This is especially useful when the communication interface is a radio interface. In this way, the communication interface can simultaneously serve as a relay station, forwarding radio signals to other communication interfaces. This allows for greater ranges to be bridged.

[0016] Particularly preferably, the signal generation device is configured to output a flow rate value representing the current flow rate of the circulating pump unit via the communication interface. This value can then be detected by the communication interface of a second connected circulating pump unit, allowing the control unit of this second connected circulating pump unit to recognize the detected flow rate value as a state variable and adjust its control scheme accordingly. In this way, the individual circulating pump unit, or its control unit, can take into account the flow rate value of a second or more additional circulating pump units arranged in the same hydraulic system in order to adjust or correct its own control scheme so that it can preferably perform its desired function independently of the other circulating pump units.

[0017] Particularly preferred, as already indicated above, is the communication interface configured for communication with a communication interface of at least one similar, preferably identical, second circulating pump unit, and the control unit of the circulating pump unit is configured such that it can receive a state variable from at least one similar, preferably identical, circulating pump unit via the communication interface and its detection function, and that the control unit then controls the drive motor of the circulating pump unit taking into account the state variable received from the communication interface. This includes adapting a control scheme based on the detected state variable.Particularly preferably, the state variable can represent, as described above, a switching on or off of at least one further circulation pump unit, or more preferably be a flow rate value representing the current flow rate of the further circulation pump unit.

[0018] According to a further preferred embodiment of the invention, the control device is designed such that the control scheme according to which the drive motor is controlled has a pump characteristic curve which is changed and preferably shifted depending on a signal detected or received by the detection function, namely a received state variable. Such a pump characteristic curve can, for example, be a proportional pressure or constant pressure characteristic curve in the QH diagram, in which the pressure is plotted against the flow rate.If the pump unit is controlled according to such a characteristic curve, an increase in the flow rate in the common branch of the hydraulic system would lead to a higher pressure drop between the pressure and suction sides of the circulating pump unit. This would cause the circulating pump to shift its speed along the given characteristic curve into a lower flow rate range, resulting in insufficient pressure in the respective branch supplied by the circulating pump. To compensate for this, the pump characteristic curve can be shifted, for example, into the higher pressure range. At a constant flow rate, this allows the pump to reach an operating point with higher pressure, thus maintaining the pressure in the respective branch despite the higher pressure drop in the common branch.Conversely, if the control device detects the shutdown or reduction of the flow rate of another circulating pump unit arranged in a parallel branch, it can shift the characteristic curve of its own control scheme into the range of lower pressures, so that in turn the flow rate and the pressure provided in its own branch can be kept essentially constant.

[0019] Preferably, the control device is configured such that the pump characteristic curve of the control scheme is shifted by a correction value, which is a function of a received or detected state variable, in particular the flow rate in the overall system into which the circulating pump unit is integrated. That is, the control unit is configured such that its detection function detects or receives the flow rate of other circulating pump units in parallel branches and calculates a correction value for shifting the pump characteristic curve, which is a function of this flow rate. Furthermore, the correction value can preferably be proportional to a correction constant, which represents a hydraulic resistance in a common branch of the hydraulic system.This constant can be determined by the control unit of the circulation pump unit in an initialization step, or it can be manually entered into the control unit, for example, using suitable input means.

[0020] Preferably, the control device is provided with an initialization function which can communicate with the control devices of parallel-connected circulation pump units via the described communication interface in such a way that the several circulation pump units arranged in parallel branches are selectively switched on and off in order to then determine the changes in the hydraulic quantities in the system and to calculate the constant from these changes.

[0021] According to a further preferred embodiment of the invention, the control device can be designed such that, after receiving a signal or a state variable via its detection function, it automatically modifies the control scheme according to which the drive motor is controlled, depending on the change in the hydraulic load, and in particular shifts a pump characteristic curve forming the control scheme. That is, here the magnitude or strength of the adjustment of the control scheme is made dependent on the magnitude of the change in the hydraulic load, in particular the flow rate or delivery quantity of a second circulating pump unit. In particular, the hydraulic load or the change in the hydraulic load caused by a further circulating pump unit is taken into account in such a way that the hydraulic state in the branch in which the circulating pump unit is arranged is essentially maintained unchanged. That is to say,Preferably, the pressure loss caused by the activation or delivery capacity of another pump unit in a common branch is essentially compensated by shifting the operating point or the pump characteristic curve of the own control scheme into the range of higher or lower differential pressures depending on the change in the pressure loss in the common branch.

[0022] The communication interface is particularly preferably designed for communication with several similar, preferably identical, second circulation pump units, and the control device is preferably designed to control the drive motor taking into account all signals or state variables received from the communication interfaces. That is to say,The circulation pump unit is designed such that more than two of these circulation pump units can be arranged in several parallel branches of a hydraulic system and communicate with each other in such a way that the changes in the hydraulic state in the overall system caused by each of them are taken into account by the individual circulation pump units in such a way that each circulation pump unit preferably controls its own drive motor in such a way that the hydraulic states in the associated branch in which the respective circulation pump unit is arranged can be maintained unaffected by the other circulation pump units. That is, the changes in state caused by the respective other circulation pump units in the hydraulic system are compensated in such a way that the circulation pump unit can maintain the desired differential pressure and / or flow rate in the associated branch essentially unchanged.

[0023] It should be understood that, where features, functions and procedures relating to the interaction of several circulation pump units have been described above, this means that the individual circulation pump unit should be designed in such a way that it can perform the described functionalities in conjunction with one or more similar or identically designed circulation pump units.

[0024] According to a particular embodiment of the invention, the control unit of the circulating pump assembly can be configured such that, upon detection of a predetermined state variable by the sensing function, it modifies the control scheme in such a way that the drive motor is switched off. Such a configuration of the circulating pump assembly enables the implementation of a priority circuit in a heating system, which allows the other heating circuits to be switched off when domestic hot water is being heated. Thus, a circulating pump assembly, preferably a circulating pump assembly as described above, can be arranged in a heating water flow path through a heat exchanger for heating domestic hot water.When this circulating pump unit is put into operation, it can generate a signal representing a predetermined state variable via a signal generation device. This signal is transmitted via a communication interface and suitable data connections, or hydraulically as described, to at least one other circulating pump unit. This second unit interprets this state variable as a signal indicating that the circulating pump unit used for domestic hot water heating has been switched on. The control unit receiving the signal can then switch off its associated circulating pump unit or its drive motor. For such a configuration, it is advantageous if the predetermined signal...The predetermined state variable is encoded in such a way that it can be assigned to a specific circulation pump unit upon commissioning of the entire system. This allows other circulation pump units to unambiguously recognize, upon receiving the signal, that the circulation pump unit responsible for domestic hot water heating has been put into operation. The circulation pump unit can also preferably have a sensor connection to which a sensor for detecting domestic hot water demand, for example, a flow sensor that can be installed in a domestic hot water pipe, can be connected. The control unit of the circulation pump unit can receive this sensor signal and evaluate it in such a way that it automatically switches on the circulation pump unit or its drive motor based on the sensor signal.In this way, domestic hot water heating can be controlled independently by a circulation pump unit, without the need for a higher-level control device to commission the circulation pump unit.

[0025] The invention further relates to the arrangement of at least two circulation pump units according to the preceding description, wherein the at least two circulation pump units are arranged in a common hydraulic circuit system. The hydraulic circuit system is particularly preferably a hydraulic heating system or a hydraulic heating installation. This expressly includes an air conditioning system. The two circulation pump units are arranged in two parallel branches or circuits of the circuit system, wherein these branches or circuits open into or have a common flow path. That is, the fluid pumped by the two circulation pumps through the two branches always also flows through the common branch or section.The at least two branches are preferably consumer branches, each containing at least one consumer, such as a heat exchanger that creates hydraulic resistance. Such a heat exchanger could be, for example, a radiator, an underfloor heating circuit, or a domestic hot water heat exchanger. The hydraulic resistances can be located downstream and / or upstream of the circulation pump unit in the individual branches. The circulation pump units in the parallel branches are of the same type and, in particular, identical design as described above. The control devices of the circulation pump units each include a signal generation device that outputs a state variable representing an operating state of that circulation pump unit.The state variable can, as described above, represent the switching on and / or off, or, for example, the flow rate (flow rate value). Furthermore, the control devices of the circulation pump units are each designed to control the associated drive motor of that circulation pump unit, taking into account the state variable detected by its sensor and output by the other circulation pump unit. This is preferably done in the manner described above. The multiple circulation pump units are of a similar and preferably identical design, so that they can mutually consider their influence on the overall system.

[0026] Further preferred features of the arrangement of at least two or more circulating pump units will become apparent from the entire preceding description. It should be understood that the features described with reference to a single circulating pump unit can also be implemented in an arrangement of several circulating pump units.

[0027] The invention further relates to a method for controlling at least two circulating pump units arranged in parallel branches of a hydraulic circuit system. As described above, the parallel branches are configured such that they converge into a common flow path, which completes a circuit through each branch. According to the method, when a second circulating pump unit is commissioned, a control scheme governing a first circulating pump unit is modified, taking into account the hydraulic power provided by the second circulating pump unit. This allows for the compensation of changes in the overall system, particularly pressure losses occurring in the common branch or pipe section caused by changes in the flow rate provided by the second circulating pump unit.Regarding the details and the exact sequence of events, reference is made to the preceding description of the circulation pump unit, in which preferred features of the method were also described. This is also expressly included in the method according to the invention.

[0028] As described, the at least two parallel branches of the hydraulic system merge into a common flow path. The at least first circulation pump unit and preferably all circulation pump units arranged in the parallel branches are controlled or regulated such that their respective control schemes are adjusted based on a hydraulic loss in the common flow path or section of the flow path, ensuring that the differential pressure across a hydraulic resistance located in one of the hydraulic branches maintains a predetermined value. That is, if the pressure loss in the common flow path increases, the differential pressure provided by the circulation pump unit in a single branch must be increased to maintain a predetermined differential pressure across the hydraulic resistance in that branch.The speed of the respective circulation pump unit must be increased if the hydraulic resistance or pressure loss in the common flow path increases, and reduced accordingly if the pressure loss in the common flow path decreases.

[0029] Preferably, a value of the hydraulic power supplied by the second circulation pump unit is transmitted from the second to the first circulation pump unit, or determined automatically by the first circulation pump unit based on a load change occurring within it. For example, the current flow rate can be transmitted or signaled as a flow rate value from one circulation pump unit to the other. Alternatively, only the switching on or off can be signaled, and the other circulation pump unit can automatically detect how much the pressure loss in the system changes due to the activation or deactivation of the second circulation pump unit. This can be detected by appropriate pressure sensors in the circulation pump unit and / or, if necessary, derived from the electrical parameters of the drive motor of the individual circulation pump unit.

[0030] The invention is described below by way of example with reference to the accompanying figures. These show: Fig. 1 schematically a circulation pump unit according to the invention, Fig. 2 schematically a hydraulic system with an arrangement of three circulation pump units according to the invention, Fig. 3 a QH diagram to illustrate the interaction of several circulation pump units, Fig. 4 schematically a hydraulic system with three circulation pump units according to a second embodiment which can be independent of the functionality of the control unit according to the invention, and Fig. 5 a hydraulic system according to Fig. 4 with an arrangement of three circulation pump units according to a third embodiment of the invention.

[0031] The circulating pump unit according to the invention is a centrifugal pump unit which can be used, for example, in a heating or air conditioning system to circulate a liquid heat transfer medium such as water. It has a pump housing 2 with an inlet 4 and an outlet 6, and at least one rotating impeller 8 inside. The impeller 8 is driven by an electric drive motor 10. Furthermore, a control unit 12 is provided in the circulating pump unit, which controls and regulates the electric drive motor 10, in particular its speed. That is, the speed of the drive motor 10 can be changed via the control unit 12 to adapt to the hydraulic conditions. In this respect, the circulating pump unit corresponds to the design of known circulating pump units.

[0032] The control unit 12 is designed to control or regulate the drive motor 10 according to at least one control scheme, i.e., for example, according to a pump characteristic curve as described in Fig. 3 This is illustrated. It is known to use, for example, proportional pressure curves as a control scheme, according to which the pressure increases proportionally to the flow rate. Alternatively, control schemes with constant pressure curves can also be used, in which the drive motor is controlled so that the pressure remains constant regardless of the flow rate. Fig. 3 The diagram shows three proportional pressure curves I, II, and III as examples in a QH diagram, in which the pressure H is plotted against the flow rate Q. The diagram is shown according to... Fig. 3Furthermore, three system characteristic curves A, B, and C are shown, which depict the pressure loss in the hydraulic circuit as a function of the flow rate Q. During operation, an operating point is established at the intersection of the pump characteristic curve and the system characteristic curve. For example, if the circulation pump unit is operated with pump characteristic curve I and the hydraulic system in which the circulation pump unit is used has system characteristic curve A, operating point 14 is established at the intersection of both characteristic curves.

[0033] Fig. 2Figure 1 schematically shows a heating system with three heating circuits or branches 16, 18, and 20. Each of the heating circuits 16, 18, and 20 of the hydraulic system contains a circulation pump unit 22a, 22b, or 22c, and one or more consumers 24, such as radiators or loops of underfloor heating. The three heating circuits 16, 18, and 20 also pass through a common flow path 26, which runs through a heat source 28, such as a boiler. In the flow direction s, the three heating circuits 16, 18, 20 branch off from each other on the outlet side of the heat source 28 and run through the circulation pump units 22a, 22b and 22c through the respective consumers 24 of the three heating circuits 16, 18, 20. On the outlet side of the consumers 24, the three heating circuits merge again into the common flow path 26 at the junction 30.The three heating circuits 16, 18, 20 can, for example, heat different parts of a building; alternatively, heating circuit 16 could be a heating circuit for underfloor heating, while heating circuits 18 and 20 represent heating circuits with normal radiators.

[0034] It is understandable that in the Figures 2 , 4 and 5 In the arrangements shown, the flow direction s could also run in the opposite direction. That is, in the examples shown, the hydraulic load or hydraulic resistance formed by the consumers 24 is located downstream of the circulation pump units 22. With an opposite flow direction, the consumers 24 would be located upstream of the circulation pump units 22. This could be the case, for example, if the several heating circuits 16, 18, 20 heat different apartments and the circulation pump units 22 are each part of an apartment station.

[0035] Depending on how many of the heating circuits are in operation, the flow rate through the common flow path 26 changes, and thus the pressure loss across the heat source 28. This results in a change in the system characteristic curve, as shown by Fig. 3 explained, changed. The in Fig. 3The system characteristic curve A shown, for example, represents a system characteristic curve when only one of the circulation pumps 22, for example, circulation pump 22a, is in operation. If heating circuit 18 is also put into operation and, for example, circulation pump 22b is additionally put into operation, the total flow rate through the common flow path 26 increases, and thus the pressure loss across the heat source 28 increases, so that the system then exhibits system characteristic curve B. If the circulation pump unit 22a is now operated with pump characteristic curve I, the operating point on this pump characteristic curve I would move from operating point 14 to operating point 32, which represents the intersection between pump characteristic curve I and system characteristic curve B. That is, the circulation pump unit 22 would reduce its speed, and the flow rate and pressure would decrease. This would result in the heating circuit 16 and the consumer 24 no longer being adequately supplied, i.e.,, the flow rate through consumer 24 could not be kept constant.

[0036] To compensate for this, the control unit 12 of the circulation pump unit is designed to modify its control scheme depending on the operation of other circulation pump units 22 in parallel branches 18, 20 of the hydraulic system. For example, the control unit 12 can shift the pump characteristic curve I, which is used as the control scheme, so that the circulation pump unit operates according to the second pump characteristic curve II, the intersection of which with the system characteristic curve B forms a new operating point 34, which is located at the same flow rate q1 as operating point 14. In this way, the flow rate q1 through the consumer 24 of the heating circuit 16 can be kept constant. At the same time, the pressure H is increased so that the higher pressure loss in the common flow path 26 is compensated for, and the differential pressure across the consumer 24 can ideally also be kept constant.To this end, the circulation pump unit 22a increases its speed and thus also its electrical power consumption. When the second circulation pump unit 22b is switched off again, the control scheme is changed back to the original pump characteristic curve I and the circulation pump unit 22a is again operated with pump characteristic curve I at operating point 14.

[0037] If the third circulation pump unit 22c in the third heating circuit 20 is also put into operation at the same time, the pressure loss across the heat source 28 increases further and the system characteristic curve takes on the shape of system characteristic curve C in Fig. 3 in this case, the control scheme of the circulation pump unit 22a can then be changed so that it follows the pump characteristic curve III in Fig. 3The system is operated in such a way that operation takes place at operating point 36, which represents the intersection between the system characteristic curve C and the pump characteristic curve III. Here, too, the flow rate q1 is kept constant, but the pressure H increases so that the increased pressure loss in the common flow path 26 is compensated for, and heating circuit 16 continues to be supplied with essentially a constant flow rate. The control schemes of the circulation pump units 22b and 22c in heating circuits 18 and 20 are adjusted accordingly, depending on how many of the other heating circuits 16, 18, and 20 are in operation. It should be understood that the circulation pump units 22a, 22b, and 22c do not necessarily have to be put into operation in this order.Depending on the heat demand in the individual heating circuits 16, 18, 20, for example only the circulation pump unit 22c can be in operation, followed by the circulation pump units 22a and 22b. Any combination and sequence is conceivable here.

[0038] The required compensations can be calculated from the hydraulic parameters as described below. The consumers 24 in the heating circuits 16, 18, 20 have hydraulic resistances R1, R2 and R3. In the three hydraulic circuits 16, 18, 20, which are in Fig. 2As shown, the flow rates s₁, s₂, and s₃ caused by the respective circulation pump units 22a, 22b, and 22c prevail. Circulation pump unit 22a generates a differential pressure h₁, circulation pump unit 22b a differential pressure h₂, and circulation pump unit 22c a differential pressure h₃. A flow rate s prevails in the common branch or flow path 26, and the heat source 28 presents a hydraulic resistance R₀. It should be understood that the hydraulic resistances R₀, R₁, R₂, and R₃ represent not only the hydraulic resistance of the consumers or the heat source, but the total hydraulic resistance in the respective branch, which is caused by line losses and similar factors. In a hydraulic heating system, the hydraulic resistances R1, R2 and R3 vary, for example, depending on the degree of opening of a thermostatic valve in the respective heating circuit 16, 18, 20.

[0039] If the differential pressures across the hydraulic resistances R1, R2, R3 are to be constant and regulated to a constant value, which is done by the control unit of the respective circulation pump unit 22, each branch has a differential pressure setpoint h*, which must be achieved across the hydraulic resistance R. In this case, the following results for the differential pressure h1, h2, h3 to be achieved by the respective pumps: h 1 = h ∗ + R 0 s 2 = h ∗ + R 0 s 1 + s 2 + s 3 2 h 2 = h ∗ + R 0 s 2 = h ∗ + R 0 s 1 + s 2 + s 3 2 h 3 = h ∗ + R 0 s 2 = h ∗ + R 0 s 1 + s 2 + s 3 2 It can be seen that the pump differential pressure h 1 , h 2 and h 3 depends on the flow rate through all branches and on the hydraulic resistance R 0 in the common branch.

[0040] It is also possible that the circulation pump units 22 are not to be regulated to a constant pressure but to a proportional pressure depending on the flow rate in order to generate a proportional pressure curve. In that case, the pressure setpoint h* would result as a value dependent on the flow rate, for example in heating circuit 16: h ∗ = as 1 2 + b In this equation, a and b represent parameters of the proportional pressure curve.

[0041] To account for the pressure losses in the common flow path 26, it is therefore necessary to know and determine the hydraulic resistance R0 in this common flow path. The hydraulic resistances R1, R2, and R3 typically change very slowly when the thermostatic valves in the heating circuits are adjusted. This makes it possible to determine the hydraulic resistance R0 by switching the circulation pump units 22 on and off for short periods of time, since the hydraulic resistances R1, R2, and R3 remain essentially unchanged during these short periods.

[0042] To determine the hydraulic resistance R0, the control units 12 of the circulation pump units 22 are preferably first caused to start up all circulation pump units 22a, 22b, and 22c by means of appropriate communication via the communication interfaces 40 and data connections 38 described below. The differential pressures h1, h2, h3 and the flow rates s1, s2, and s3 are then determined by the control units 12 and preferably exchanged with each other via the data connections 38. These values ​​can be acquired by suitable sensors in the circulation pump units 22 and / or by calculation based on electrical parameters of the drive motor of the respective circulation pump unit 22. Once these measurements have been recorded, for example the circulation pump unit 22b can be switched off and pressure values ​​h 1 , h' 2 , h 3 and flow rates s' 1 , s' 2 and s' 3 can be determined.From these measurements, the hydraulic resistance R 0 in the common flow path 26 can be determined by solving the following systems of equations with two unknowns.

[0043] A first example is based on the pressure h 1 of the circulation pump unit 22a: h 1 = R 1 s 1 2 + R 0 s 1 + s 2 + s 3 2 h 1 = R 1 s ′ 1 2 + R 0 s ′ 1 + s ′ 3 2 This results in the following for R 0: R 0 = s ′ 1 2 h 1 − s 1 2 h 1 s ′ 1 2 s 1 + s 2 + s 3 2 − s 1 2 s ′ 1 + s ′ 2 2

[0044] A second example is based on the pressure h 2 of the circulation pump unit 22b: h 2 = R 2 s 2 2 + R 0 s 1 + s 2 + s 3 2 h ′ 2 = R 0 s ′ 1 + s ′ 3 2 This results in the following for R 0: R 0 = h ′ 2 s ′ 1 + s ′ 2 2

[0045] A third example is based on the pressure hs of the circulation pump unit 22c: h 3 = R 3 s 3 2 + R 0 s 1 + s 2 + s 3 2 h 3 = R 3 s ′ 3 2 + R 0 s ′ 1 + s ′ 3 2 This system of equations yields a solution similar to the solution for the circulation pump unit 22a.

[0046] It is also possible to perform additional tests or measurements, for example by switching off the circulation pump unit 22b and the circulation pump unit 22c. The following three equations for the circulation pump unit 22a may result, for example: h 1 = R 1 s 1 2 + R 0 s 1 + s 2 + s 3 2 h 1 = R 1 s ′ 1 2 + R 0 s ′ 1 + s ′ 3 2 h 1 = R 1 s ′ 1 2 + R 0 s ′ 1 2 These equations can be solved by linear regression.

[0047] There may be cases in which it is not possible to switch off one of the circulation pump units 22. In such a case, it may also be possible to change only the differential pressure h across the respective circulation pump unit 22 by changing the rotational speed. For example, the pressure of circulation pump unit 22b could be changed from h₂ to h'₂ by changing the rotational speed. The following equations result for the three circulation pump units 22a, 22b, and 22c: h 1 = R 1 s 1 2 + R 0 s 1 + s 2 + s 3 2 h 1 = R 1 s ′ 1 2 + R 0 s ′ 1 + s ′ 2 + s ′ 3 2 h 2 = R 2 s 2 2 + R 0 s 1 + s 2 + s 3 2 h ′ 2 = R 2 s ′ 2 2 + R 0 s ′ 1 + s ′ 2 + s ′ 3 2 h 3 = R 3 s 3 2 + R 0 s 1 + s 2 + s 3 2 h 3 = R 3 s ′ 3 2 + R 0 s ′ 1 + s ′ 2 + s ′ 3 2 From these, the hydraulic resistance R0 can be determined. If, after an initial test in this manner, the hydraulic resistance R0 in the common branch 26 has been determined, the change in flow rate s in the common flow path 26 can subsequently be taken into account for adjusting the pump characteristic curve in each individual pump unit 22 when the flow rate is changed by switching on or changing the speed of one of the circulating pump units 22. The pump characteristic curve I, II, III is preferably shifted by a factor or by a correction value, which is proportional to the hydraulic resistance R0 in the common flow path 26 and is an increasing function of the sum of the flow rates, i.e., the flow rate s in the common flow path 26.

[0048] To achieve this described functionality of adapting the control schemes depending on the operation of the circulation pump units 22 in the parallel heating circuits 16, 18, 20, communication between the circulation pump units 22a, 22b and 22c is provided according to the invention. According to a first embodiment of the invention, which is described in Fig. 2As shown, the circulation pump units 22a, 22b, and 22c can be directly interconnected via data connections 38. These data connections 38 can be implemented as a wired data bus or wirelessly via radio links. The control units 12 of the circulation pump units 22 have a communication interface 40 for this purpose. This interface interacts within the control unit 12 with a detection module 42, which provides a detection function. The detection module 42 can be implemented as a software module within the control unit. Furthermore, each of the control units 12 has a signal generation unit 44, which, according to a first embodiment, can also be connected to the communication interface 40, as shown in Fig. 1As shown. In this embodiment, the communication interface 40 preferably operates bidirectionally. The signal generation device 44 can also be implemented as a software module in the control unit 12.

[0049] The signal generation unit 44 generates a signal during the operation of the respective circulation pump unit 22. This signal represents a state variable and is output to the other circulation pump units 22 via the communication interface 40 and the data connection 38. In its simplest form, the state variable can merely signal that the respective circulation pump unit 22 is switched on or off. Alternatively, the state variable can be a flow rate value representing the respective flow rate of the pump unit 22. The flow rate can either be measured in the circulation pump unit 22 or derived from electrical quantities by the control unit 12.

[0050] If, for example, in the embodiment according to Fig. 2Initially, as described above, only the circulation pump unit 22a is in operation, and later the circulation pump unit 22b is switched on, the signal generation unit 44 of the circulation pump unit 22b generates, for example, a flow rate value that indicates the flow rate of the second circulation pump unit 22b. This flow rate value is determined via the communication interface 40 and the data connection 38 to the first circulation pump unit 22a. Its control unit 12 processes this signal in the detection module 42 in such a way that it now recognizes the change in the system characteristic curve from system characteristic curve A to system characteristic curve B and accordingly changes the control scheme of its control unit 12, e.g., from pump characteristic curve I to pump characteristic curve II.When the third circulation pump unit 22c is switched on, this occurs accordingly, with circulation pump unit 22c also transmitting its flow rate value via data connection 38 to circulation pump units 22b and 22a, so that these two circulation pump units can then adjust their pump characteristic curves as a control scheme. Conversely, circulation pump unit 22c also receives the flow rate values ​​from circulation pump units 22a and 22b, so that it can immediately adapt its control scheme to the hydraulic state of the system resulting from the simultaneous operation of the other circulation pump units 22a and 22b upon commissioning.

[0051] Instead of directly transmitting the flow rate values ​​via data connection 38, as described, only a signal indicating switching on and off could be transmitted. If the control unit 12 of the first pump unit 22a is only informed that the second circulation pump unit 22b is switched on or operating, the control unit 12 can automatically detect, via the detection module 42, how the system characteristic curve changes from the changes in electrical parameters and, if applicable, directly measured hydraulic parameters in the circulation pump unit 22a, and adjust the pump characteristic curve accordingly. This can be done similarly in the other two circulation pump units 22b and 22c.

[0052] The networking or linking for communication between the circulation pump units 22a, 22b and 22c can also be carried out in an alternative way, such as in Fig. 4The connection is made via a central control unit 46. The control unit 46 is connected to the circulation pump units 22 via individual data connections 38'. These data connections 38' can be wired or wireless, for example, radio connections. The central control unit 46 can be configured to take over the complete function of the control devices 12 by specifying the respective speed for the drive motor 10 to the circulation pump units 22a, 22b, 22c, for example, via a PWM signal input of the circulation pump units 22a, 22b, and 22c. Such a central control system and corresponding circulation pump units are not according to the invention. However, if the control unit 46 only performs the function of transmitting the state variables or signals between the circulation pump units 22, as described above, then the Fig. 4The illustrated embodiment and corresponding circulation pump units according to the invention. This can be particularly advantageous if the communication interfaces 40 of the control units 12 are galvanically isolated from the other parts of the control unit, so that the communication links 38' require an external power supply via the control unit 46.

[0053] According to a third possible embodiment, which is based on Fig. 5As described, communication between the circulation pump units 22a, 22b, and 22c is hydraulic. That is, in this embodiment, the circulation pump units 22a, 22b, and 22c do not require a communication interface 40. Instead, the signal generation device 44 generates a hydraulic signal when each circulation pump unit 22 is commissioned. This is achieved by starting the drive motor 10 according to a predefined pattern, for example, by briefly switching it on and off several times in a specific pattern before permanent commissioning. This leads to pressure fluctuations in the entire hydraulic system, which can be detected by the other circulation pump units 22 through momentary changes in the hydraulic state. The detection module 42 of the circulation pump units 22 is designed accordingly for this purpose.If a circulating pump unit 22 in the system detects the pattern that signals the commissioning of another circulating pump unit 22, it can recognize the change in the system characteristic curve A, B, C from its electrical parameters or internal sensor signals in the manner described above and adjust the pump characteristic curve I, II, III accordingly, as described above. If necessary, such a hydraulic signal indicating the operation of a pump unit can also be generated repeatedly at regular intervals by the signal generation device 44, so that the circulating pump units 22 can continuously monitor, via their detection devices or detection modules 42, whether other circulating pump units 22 are operating in the same hydraulic system. Reference symbol

[0054] 2 Pump housing 4 Inlet 6 Outlet 8 Impeller 10 Drive motor 12 Control unit 14 Operating point 16, 18, 20 Heating circuits 22, 22a, 22b, 22c Circulating pump units 24 Consumer 26 Common flow path 28 Heat source 30 Discharge point 32, 34, 36 Operating points 38, 38` Data connections 40 Communication interface 42 Acquisition module 44 Signal generation unit 46 Control unit I, II, III Pump characteristics A, B, C System characteristics Q Flow rate H Pressure R Hydraulic resistance s Flow rate q 1 Flow rate h Differential pressure

Claims

1. A circulation pump unit (22) having an electric drive motor (10) and an electronic control device (12) for controlling the drive motor (10), wherein the control device (12) is designed for controlling the speed of the drive motor (10) according to a control scheme (I, II, III), wherein the control device (12) has a signal generation device (44) which is designed to generate a signal representing the switching on and / or off or a speed change of the drive motor (10), and a recording function (42) which is designed to record a status variable representing an operating state from at least one parallel hydraulic branch (16, 18, 20) having a second circulation pump unit (22) of the same kind in that it detects a signal generated by the signal generation device of the other or the plurality of other circulation pump unit(s) as a status variable, which signal represents the switching on and / or off or a speed change of the at least one second circulation pump unit (22), and wherein the control device (12) is designed in such a manner that it can adjust its own control scheme (I, II, III) on the basis of a status variable recorded by the recording function (42) and the drive motor (10) can be controlled in such a manner by the control device (12), taking account of the signal that was recorded, that a differential pressure above a hydraulic resistance located in a single hydraulic branch of the hydraulic branches has a predetermined value.

2. The circulation pump unit (22) according to claim 1, in which the recording function (42) is designed for recording a signal in the form of at least one predetermined pattern of a hydraulic load acting on the circulation pump unit (22).

3. The circulation pump unit (22) according to one of the preceding claims, in which the control device (12) has a communication interface (40) which is connected to the recording function (42) in such a manner that the recording function (42) can receive a signal via the communication interface (40).

4. The circulation pump unit (22) according to one of the preceding claims, in which the signal generation device (44) is designed for generating a hydraulic signal.

5. The circulation pump unit (22) according to one of the preceding claims, in which the control device (12) has a communication interface (40) which is connected to the signal generation device (44) in such a manner that the signal generation device (44) can send a signal or a value via the communication interface (40).

6. The circulation pump unit (22) according to claim 5, in which the signal generation device (44) is designed in such a manner that it outputs a flow rate value representing the current flow rate of the circulation pump unit (22) via the communication interface (40).

7. The circulation pump unit (22) according to claim 6, in which the communication interface (40) is designed for a communication connection with a communication interface (40) of at least one second circulation pump unit (22) of the same kind, the control device (12) is designed in such a manner that, via the communication interface (40) and the recording function (42), it can receive a status variable from at least one second circulation pump unit (22) of the same kind via the communication interface (40), and that the control device (12) controls the drive motor (10) taking account of the status variable received from the communication interface (40).

8. The circulation pump unit (22) according to one of the preceding claims, in which the control device (12) is designed in such a manner that the control scheme (I, II, III) according to which the drive motor (10) is controlled has a pump characteristic (I, II, III) which is changed and preferably shifted in the form of a received status variable, depending on a signal that is detected or received by the recording function (42).

9. The circulation pump unit according to claim 8, in which the control device is designed in such a manner that the pump characteristic (I, II, III) is shifted by a correction value which represents a function of a received or recorded status variable.

10. The circulation pump unit (22) according to one of the preceding claims, in which the control device (12) is designed in such a manner that, after receiving a signal from the recording function (44), it automatically changes the control scheme (I, II, III) as a function of the change of the hydraulic load and in particular shifts a pump characteristic (I, II, III) that forms the control scheme.

11. The circulation pump unit (22) according to one of claims 6-10, in which the communication interface (40) is designed for communication with a plurality of second circulation pump units (22) of the same kind and the control device (12) controls the drive motor (10), taking account of all status variables received from the communication interface (40).

12. The circulation pump unit (22) according to one of the preceding claims, in which the control device (12) is designed in such a manner that it changes the control scheme in such a manner in the case of a predetermined status variable recorded by the recording function (42) that the drive motor (10) is switched off.

13. An arrangement of at least two circulation pump units (22) of the same kind according to one of the preceding claims, in which the at least two circulation pump units (22) are arranged in a hydraulic circulation system in two mutually parallel branches (16, 18, 20), and the control devices (12) of the circulation pump units (22) in each case have a signal generation device (44) which outputs a status variable which represents an operating state of this circulation pump unit (22), and the control devices (12) of the circulation pump units (22) are designed in such a manner that they control the associated drive motor (10) of the circulation pump unit (22) in such a manner, taking account of the status variable that is recorded by its recording function (44) and output by the other circulation pump unit (22), that a differential pressure above a hydraulic resistance located in a single hydraulic branch of the hydraulic branches has a predetermined value.

14. A method for controlling at least two circulation pump units (22) of the same type according to one of Claims 1-12 which are arranged in a hydraulic circulation system in mutually parallel branches (16, 18, 20), preferably two mutually parallel consumer branches (16, 18, 20), in which, during the commissioning of a second circulation pump unit (22), a control scheme (I, II, III), according to which a first circulation pump unit (22) is controlled, is changed taking account of the hydraulic output provided by the second circulation pump unit (22), and in which the at least two parallel branches (16, 18, 20) of the hydraulic system open into a common flow path (26) and at least the first circulation pump unit (22) and preferably all of the circulation pump units (22) arranged in the parallel branches (16, 18, 20) are controlled such that in each case their control scheme (I, II, III) is adapted in such a manner on the basis of a hydraulic loss in the common flow path that a differential pressure above a hydraulic resistance (24) located in a single hydraulic branch of the hydraulic branches (16, 18, 20) has a predetermined value.

15. The method according to claim 14, in which a value of the hydraulic output provided by the second circulation pump unit (22) is transmitted from the second circulation pump unit (22) to the first circulation pump unit (22) or is determined automatically by the first circulation pump unit (22) on the basis of a load change that occurs in the first circulation pump unit (22).