Circulation pump with a printed circuit board as motor stator for propelling a rotor

Abstract

The present invention belongs to the field of circulation pumps designed for forced flow of fluids in different hydraulic systems. The circulation pump comprises a wet, hydraulic part and a dry, electric-electronic part. The hydraulic part comprises a housing with two or more inlet-outlet openings for connection to a pipeline, wherein inside the housing a rotor, a rotor axis, a magnet, a seal and an impeller are provided. The electric-electronic part comprises a housing inside which control electronics are provide to control the pump or to control the drive based on user settings. Further, the electric-electronic part comprises a PCB dividing wall, which is designed as a printed circuit with integrated stator coil, and which at the same time functions as a wall to divide the hydraulic part of the electric-electronic part. The PCB dividing wall thus divides the hydraulic part and the electric-electronic part, wherein its surface with the circuit on the side of the electric-electronic part is protected against water or moisture, wherein the other surface of the PCB dividing wall facing the hydraulic part is in contact with the seal, preferably circularly shaped, which ensures sealing and prevents water or moisture from entering the electric-electronic part.

Description

Field of the invention

[0001] The present invention belongs to the field of circulation pumps designed for forced flow of fluids in different hydraulic systems. The present invention relates to a circulation pump, mostly intended for ensuring recirculation of hot sanitary water (recirculating line), and also low and high temperature systems of central heating or heating of individual recirculating lines.Background of the invention and the technical problem

[0002] The technical problem addressed by the present invention is related to construction of a new product, which has a completely different technical and constructional solution if compared to currently existing circulation pumps. It is based on the use of printed circuit board (PCB) as the winding of the stator.

[0003] The current constructions of circulation pumps are based on a tubular stator with a wire winding, in which a bushing with rotor and shaft is installed. The rotor shaft is provided with magnets, a bearing, and a stepper motor driver - impeller. The rotor assembly is placed in the hydraulic casing of the pump as a construction element, which separates the wet pumping part from the dry propelling part of the pump.

[0004] The basic technical solution of the current prior art and problems with production of wet-liquid circulation pumps resides in existing technology of manufacturing stators comprising an arbitrary number of lamellas to which an arbitrary number of copper wire windings are inserted, wherein upon provision of electric current a spinning magnetic field is created, which in interaction with a permanent magnet produces torque arranged to rotate the rotor of the pump.Prior art

[0005] Several pumps comprising a motor with a PCT stator exist. These are produced by companies Bosch, Lennox, Vaillant, Danfoss, Grundfos, Viessmann, Daikin, Wilo, Xylem, Lowara, Vortex and other leading manufacturers in this field.Description of the solution to the technical problem

[0006] The present invention solves problems of known solutions, as defined in the independent claim, wherein the preferred embodiments are defined in dependent claims. Solutions known to the applicant are not similar to the present invention.

[0007] The essence of the invention is in that the classic stator winding is replaced with a single piece PCB printed circuit, which at the same time functions as a dividing wall for separating the dry part of the pump from the wet part. In continuation of this text, this element will be named PCB dividing wall. Consequently, the stator has several functions, for which in prior art solutions separate, different components such as stator, motor cup, bushing, division wall, electronic controller, connection cables and connectors were needed. The present solution significantly reduces dimensions of the circulation pump, which is smaller, lighter, and less robust if compared with common pumps with standard stator windings.

[0008] The circulation pump according to the invention is an assembly of a wet, hydraulic part and a dry, electric-electronic part, which are installed in a two-part square-shaped housing.

[0009] The hydraulic part comprises a housing, which is on one end open, wherein any suitable rotor, rotor shaft and sealing are installed in said housing. Said sealing is installed on the part which will be in contact or connected to the electronic-electric part. The hydraulic housing is made of cast plastic, brass, stainless steel, or other materials that provide sufficient strength to withstand system pressure. The hydraulic housing is designed with at least two or more inlet / outlet round openings or standardized holes with threads for connection to the pipeline. The hydraulic housing can be adapted to the requirements of an individual system, especially in view of pipeline dimensions and consequently the openings or holes for connection to the pipeline. In a possible embodiment, the pipeline dimension is DN15 and 1 / 2". The hydraulic part has a standard design and can be designed in any manner known to a person skilled in the art.

[0010] An important part of the circulation pump according to the invention is the electric-electronic part, which comprises the PCB dividing wall and control electronics arranged to control operation of the pump or serves to control the drive based on user's settings, respectively. This part may be provided with an additional circuit, which is connected to the PCB circuit with a suitable connector. All these components are installed in a composite plastic housing or a housing made from other above-mentioned materials. The housing is provided with holes for attachment screws for attachment to the hydraulic housing of the circulation pump. According to a possible embodiment, attachment is achieved with four screws, however, more or fewer screws can be used or both housings are provided with threads for installation one into the other.

[0011] The PCB dividing wall thus divides the hydraulic part and the electric-electronic part, wherein its surface with the circuit on the side of the electric-electronic part is protected against water or moisture, wherein the other surface of the PCB dividing wall facing the hydraulic part is in contact with the seal, preferably circularly shaped, which ensures sealing and prevents water or moisture from entering the electric-electronic part. On the back side of the electric-electronic housing of the pump a socket for connecting a power cable is provided.

[0012] Between the wet part and the electric part of the pump the main feature of the invention is installed, i.e. the PCB dividing wall with an integrated winding for the stator of the pump motor. As already described, the PCT printed circuit forms the dividing wall at the same time functions as a sealing barrier that separates the wet housing from the electric part of the pump. Preferably, it is designed as a composite roung plate comprising several glued layers of copper foil and insulation material. A HDI (High Density Interconnect) solution can be used, wherein a special construction and technology (sequence of drilling, gluing and metallisation) ensures watertightness of the pump, connection holes and impermeability for the pumped liquid, wherein the printed circuit of the stator winding and a part or all electronic control for controlling pump operation is provided.

[0013] The layers of the printed circuit from the hydraulic housing to the electronic housing have the following sequence: a) copper foil with grooves that reduce the passage of water vapor, while preventing eddy currents in the magnetic field. It is separated from the next layer by an insulating layer of the printed circuit, which serves both as electrical insulation and a water seal. This part, together with the mechanical strength of the following layers, replaces the motor can of the wet-running pump. Together with the insulating layer, it seals the penetration of water and provides electrical insulation of the motor from the wet part of the pump, which means that this part of the integrated circuit with the winding faces the rotor magnet in the wet part of the pump. b) several electrically connected stator coils, separated by an insulating layer, drawn according to the rules of printed circuit design. These transmit torque to the pump rotor using electromagnetic force. This part of the circuit replaces the wire stator of the pump wound on an iron core. These layers are repeated depending on the desired characteristics of the motor. Preferred embodiments comprise 8 or 10 such layers, however, the technology allows any number from 1 to over 64. c) the top layer, electrically connected to the stator coils, comprises a part or all electronic control components for controlling the motor and pump. The remaining space can be used for additional stator coils. This part serves as the electronic control and part of the motor, and together with the lower layers also provides mechanical strength to sustain the pressure, which does not require the additional use of pots and baffles or other supports, cables, connectors, etc. Therefore, the electronic control part of the PCB dividing wall is located in the electrical part of the pump housing.

[0014] This construction significantly reduces the number of pump parts, lowers manufacturing costs, ensures simplicity of manufacturing and enables smaller dimensions of the product, while at the same time achieving the Q-H curve.

[0015] The PCB diving wall has thus a double function, namely, the printed stator winding on the side of the wet part of the pump can be adjusted arbitrarily to the construction and requirements regarding the power and rotations of the pump, and on the side of the electronic-electric housing at least a part or all electronic components needed for controlling and operating the pump can be installed.

[0016] The electronic housing positions the PCB dividing wall on the hydraulic housing, provides the necessary sealing force for system pressure, houses the user interface for controlling the pump and the connector for mounting the power cable, while at the same time provides mechanical and electrical protection for the entire pump interior.

[0017] Impermeability of the connection between the electric housing and the wet housing is ensured with a seal, which is preferably shaped as an o-ring seal, on which the PCB dividing wall is installed, wherein said PCB dividing wall covers the seal in its entirety.

[0018] By screwing the attachment screws through the electric housing in the threaded holes on the wet housing, the housings engage and consequently the circular printed circuit compresses the o-seal, which ensures watertightness between both housings.

[0019] The interior of the wet part housing is designed to achieve the expected characteristic Q-H (flow-pressure) curve. In the continuation of the text, the term rotor will be used for the complete rotating subassembly in the hydraulic part, and impeller for the hydraulic element that is part of the rotor and accelerates the water that flows through it as it rotates.

[0020] The rotor may be designed in any suitable manner and is installed on the rotor axis. According to a possible embodiment, the rotor axis is fixed in the hydraulic housing. Otherwise, the rotor is adjusted to the electromotor, which also defines the position of the magnet, the impeller, and the axis. The skilled person working in this field knows the constructional details and minor adjustments.

[0021] The impeller can be designed in any suitable manner known to the skilled person. The impeller may also be made from one extruded piece of composite plastic, with circular shape having a circular back wall with a through-hole in the centre, through which the rotor axis is installed.

[0022] A magnet is installed on the impeller, which upon interaction with the magnetic field created by the stator, generates torque which is transmitted to the pump driver. The magnet also has a through hole in the middle for positioning on the impeller, which is designed so that the magnet is always less than a millimetre away from the PCB printed circuit board, which is also the chamber wall. The connection of the magnet to the impeller can be made either by gluing, welding or a mechanically detachable or non-detachable connection. The impeller and the magnet together form the pump rotor.

[0023] The invention will be described in further detail based on exemplary embodiments and figures, which show: Figure 13D representation of the pump according to the invention Figure 2Cross-section of the pump shown in figure 1, which comprises a side view of installation of individual parts Figure 3The impeller according to a possible embodiment in 3D (figure 3.1) and in cross-section (figure 3.2) Figure 4stator PCB dividing wall from the side of the electric part of the pump in the first winding level Figure 5Connection of external control units to the upper PCB layer Figure 6A layer of the PCB dividing wall with defined lines of the printed circuit and input / output sites for connecting individual circuit layers.

[0024] The invention shown in figure 1 and 2 represent a 3D view of the pump C with the PCB printed circuit 3, wherein figure 1 shows a disassembled state as an installation or service view of all parts of the pump. Said pump according to the invention comprises: the electric-electronic part with the housing, the hydraulic part with a housing comprising the rotor, the rotor axis, the seal, the impeller, and the magnet, as well as the PCB dividing wall with printed circuit with integrated winding for the electromotor, said PCB dividing wall installed between the hydraulic and the electric-electronic part, so as to divide both parts and prevents the water or moisture from entering the electric-electronic part.

[0025] The housing of the electronics 1 is shown in figures 1 and 2 and is designed as a shell or a cup with a square shape, provided with holes for screws 1.3 at all four corners, wherein said screws end with a flat bottom 1.4. With said screws the housing of the electronics is screwed on the hydraulic housing 2. The bottom part 1.6 of the housing 1 a groove 1.5 for positioning the PCB dividing wall 3 is provided.

[0026] The upper surface of the electrical housing 1 shown in figure 1 the surface 1.1 is flat and buttons or sensors for setting pump operation are provided, wherein under the surface a power connector 1.8 is provided to allow power supply to the pump C.

[0027] The power connector 1.8 has to ensure watertightness and does not form a part of the invention. It is only show to disclose how the pump C is powered.

[0028] The housing 1 is made as a casting from a composite plastic, but it can be also made from other suitable materials.

[0029] The housing 2 for the wet part of the pump as shown in figures 1 and 2 is partly circular and is provided with an entry opening 2.2 on the left side, which is a tubular space for entering the fluid F1, and with an exit opening 2.3, which is a tubular space for the fluid F1 that leaves the housing. The openings 2.2 and 2.3 are provided with inner threads 2.2.1 and 2.3.1 for installation into a pipeline or connection of other elements such as a check valve, a ball valve and other elements of such systems.

[0030] The tubular entry opening 2.2 and space ends in a circular space 2.4 for allowing the fluid into the impeller 7. Between the outer entry edge 7.6 on the exit edge of the impeller 7.7 and the top of the entry space 2.4 before the impeller a groove 2.4.1 for sealing is provided, said groove being arranged for reliable sealing of the pressure differences provided by the impeller 7. At the same time, the entry edge 7.6 must not contact the wet, hydraulic housing 2.

[0031] Due to electromagnetic forces created by the printed circuit 3.4, torque on the magnet 4 and impeller 7, on which the magnet 4 is installed, is created. The impeller 7 using blades 7.1 accelerates water through channels 7.3 between them. The water exits the channel at space 7.7 into a collector 2.5, from which it continues movement to the tubular space of the opening 2.3 and exits the housing and continues motion into the pipe system.

[0032] In the centre of the hydraulic housing 2 a holder 2.7. is provided, on which the axis of the rotor 5 is provided, the holder being a part of the casting of the housing 2.

[0033] The impeller 7 is shown in figures 3, 3.1 and 3.2,which has a front-bottom wall 7.2, a back-upper wall 7.5 and at least one blade 7.1. The number of blades is arbitrary. The magnet 4 is mounted on the pesto 7.10 by gluing, welding, mechanical means or any other known manner. The centre of the pesto 7.10 is provided with an upper plate 7.9 for limiting rotor movement, which is defined by the axial position of the rotor.

[0034] The channel of the impeller is limited by the front wall 7.2, the back wall 7.5 and blades 7.1 as well as the magnet 4. The blades 7.1 may be shaped in a manner to accelerate the fluid F1 by rotation of the impeller at a determined flow with as low hydraulic losses as possible. At the same time their shape is simple to allow manufacturing from a single piece of plastic. The blades also connect the front and the back walls of the impeller.

[0035] The centre of the impeller 7 is provided with a hole 7.4 for installing the rotor on the axis 5.

[0036] The rotor axis 5 of the pump C is a grinded and polished cylinder with a suitable diameter. A part of the axis is received in a hole on the holder 2.7 with a tight fit, while the remaining surface of the rotor axis 5 received a magnet and the impeller 7 with a loose fit.

[0037] Between the wet part 2 and the electric part 1 the PCB dividing wall 3.1 is inserted, which is provided with an integrated coil 3.4 functioning as the stator of the pump. The PCB dividing wall 3 is designed as a circular plate comprising the multilayer printed circuit comprising several glued layers of copper foil and insulation material, while copper layers are mutually connected with metalized exit holes (connections) 3.5 and inlet connections 3.7 visible in figure 6.

[0038] The first layer of the PCB 3.2 on the bottom side is in contact with water in the hydraulic housing 2, wherein watertightness is ensured with an o-ring 6 and suitably shaped bottom layer of copper 3.2. On the upper side 3.3 control electronics 3.6 for driving the motor is provided or connectors for connecting the stator 3 to the external control. All layers in between bottom and upper layers are provided with stator coils 3.4 mutually connected with connections 3.5.

[0039] The shown circulation pump C differs from other known pumps in the PCB diving wall between the dry and wet parts of the pump. In addition, installation of the rotor rotating in the fixed axis 5 in the hydraulic part 2 differs from known solutions, wherein the movement of the rotor is axially limited by the shape of the impeller 7, the housing 2 and / or the rotor axis 5.

Claims

1. A circulation pump (C) comprising an assembly of a hydraulic part and an electric-electronic part, wherein the hydraulic part comprises a housing (2) with at least two or more inlet / outlet openings for connection to a pipeline, inside which a rotor, rotor axis, a magnet (4), a seal and a impeller (7), wherein the electric-electronic part comprises a housing (1) inside which control electronics is provided to control pump operation or to control drive based on user settings, wherein said circulation pump is characterized in that the electric-electronic part comprises a PCB dividing wall (3), which is designed as a printed circuit with integrated winding for a pump stator, whole at the same time the PCB dividing wall functions as a wall, wherein said PCB dividing wall (3) is installed between the the hydraulic part and the electric-electronic part, wherein its surface with the circuit on the side of the electric-electronic part is protected against water or moisture, wherein the other surface of the PCB dividing wall facing the hydraulic part is in contact with a seal, preferably circularly shaped, which ensures sealing and prevents water or moisture from entering the electric-electronic part.

2. The circulation pump (C) according to claim 1, wherein the PCB dividing wall is designed as a composite circular plate comprising several glued layers of copper foil and insulation material.

3. The circulation pump (C) according to claim 1 or claim 2, wherein during installation of the housing (1) on the hydraulic housing (2) an o-ring (6) seal is provided, wherein the housing (1) of the electronics with the PCB dividing wall (3) is placed on the o-ring, wherein the whole assembly is connected with screws (1.2).

4. The circulation pump (C) according to any of the preceding claims, wherein the electronic housing (1) is provided with power plug for a power connector (1.8) to provide electric energy for pump operation.

5. The circulation pump (C) according to any of the preceding claims, wherein the hydraulic housing (2) is provided with a circular tubular space (2.2) for entering the fluid (F1), which continues into a tubular section (2.4) and to the impeller (7), which pushes the fluid into a collector (2.5) as well as tubular outlet (2.3) of fluid (F2).

6. The circulation pump (C) according to any of the preceding claims, wherein the hydraulic housing (2) has a holder (2.7) of the rotor axis (5) provided in the centre.

7. The circulation pump (C) according to any of the preceding claims, wherein the rotor axis (5) is installed in the holder (2.7), on which the impeller (7) with the magnet (4) is installed.

8. The circulation pump (C) according to any of the preceding claims, wherein the impeller (7) is an injection-moulded piece made of composite plastics having any number of blades (7.1) between the front wall (7.2) and the rear wall (7.5), said blades arranged to connect said walls, wherein the blades (7.1) are designed to allow a required hydraulic flow-pressure property of the pump.

9. The circulation pump (C) according to any of the preceding claims, wherein the back wall (7.5) of the impeller has an elongated pesto with a hole (7.4) for installation on the rotor axis (5) on one end and a pesto for positioning and installation of the magnet (7.10) on the other end.

10. The circulation pump (C) according to any of the preceding claims, wherein the PCB dividing wall (3) is designed as a circular plate with multilayer printed circuit with integrated stator winding comprising several mutually glued layers of copper foil, wherein the number of layers is preferably from 2 to 64, and layers of insulation material, wherein parts of the winding (3.4) are connected through metalized holes (3.5), and wherein on the surface oriented towards the housing of the electronics control electronics (3.6) or connectors for connection to external electronics are provided, and wherein on the surface oriented towards the hydraulic housing (2) a lacquered layer of copper (3.2) is provided, which does not comprise the stator winding, but the copper is designed as a watertight layer, which also prevents electro-magnetic losses in the magnetic field induced by the winding (3.4) of the stator.

11. The circulation pump (C) according to any of the preceding claims, wherein the rotor with the magnet (4) in the hydraulic housing (2) is positioned so as to allow the distance between the magnet (4) and the PCB dividing wall (3) less than 1 mm.

12. The circulation pump (C) according to any of the preceding claims, wherein several electrically connected printed coils (3.4) of the stator are separated with insulation layers, and wherein electromagnetic forces translate torque to the pump rotor (C).

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