EP2918721B1 - Pumping device for a water-conducting device and water-conducting device - Google Patents

Description

Pumping device for a water-conducting device and water-conducting device
The invention relates to a pumping device for a water-bearing device such as washing machine or dishwasher with a treatment container for receiving washing liquid for treating material to be treated within the treatment container, for pumping or pumping over washing liquid, comprising a pump with an electric motor and a rotatable impeller for conveying the liquid connected to a power stage controlled by a control means for controlling the flow rate, the control means being arranged to detect electric parameters supplied to the pump and to influence the supply of electric power or current to the motor depending on these parameters ,

For washing laundry in a drum washing machine, the laundry is moved in the rotating drum, whereby the wetting of the laundry with the washing liquid and the washing mechanism are effected. In this case, there is water in the tub or in the drum, wherein the dirt is flushed out by the movement of the laundry. In order to bring the wash as completely as possible in connection with the laundry, it is known to raise the laundry and a portion of the washing liquid by means of drum rotation from the lower region, so that the laundry items located in the drum are sprinkled from above with washing liquid or with the Washing liquid are mixed. After washing, the washing liquid is pumped, wherein the washing liquid is expelled from the laundry due to the centrifugal force occurring from the laundry by a so-called intermediate centrifuging. The disadvantage here is that when pumping or pumping strong fluctuations in the liquid flow due to the self-adjusting flows and the resulting amount of liquid occur. Furthermore, depending on the setup conditions different requirements with regard to the flow rate for the drain pump, depending on how the drain hose of the device is laid.

From the DE 10 2010 028 614 A1 a pump device is known in which the control of the pump takes place in dependence on detected parameters. In this case, the load of the pump is determined on the basis of the parameters recorded. Based on the load of the demand for electrical power is determined and fed to the pump. This regulation is quite complicated and vulnerable, since each operating state leads to an adaptation and change of the electric pump power.

From the US 2004/0088791 A1 It is known to control a pump with an electronically commutated motor for a Umfluteinrichtung or drain device by means of a frequency converter. In this case, the pump power compared to the rated power can be reduced if there is a risk that the pump sucks air when the water level in the machine falls below a lower limit.

From the EP 1 638 201 B1 It is known to control the drain pump of a drain device by means of an electrical switch to make an adjustment of the engine operation to the pump load. In this case, a partial load operation is detected and then the engine briefly or switched off or off or switched in a predetermined duty cycle.

From the DE 10 2007 052091 A1 It is known to determine the flow rate of a liquid during a pumping process by adding up the power consumption in water-bearing household appliances.

The invention is therefore based on the object to provide a pump device for a water-bearing device that reliably provides the predetermined flow rate in each case of operation and also to provide optimal operation in terms of pumping or flooding in a water-bearing device.

The object is achieved by a pump device having the features of independent claim 1, and by a water-conducting device according to claim 9 or 10. Advantageous embodiments will be apparent from the respective dependent claims.

In the case of the pump device according to the invention, it is provided that the electrical power consumed by the pump or the absorbed current, in particular the effective component of the current, serves as an electrical parameter, wherein the control device is designed to use the power stage to supply the electrical power or current supplied to the motor depending on the detected parameters, so that sets a predetermined electric power or a predetermined current. It is therefore independent of the operating conditions, such as load on the impeller, air pressure, water pressure or Abpumphöhe, so the position of the hose end with respect to the machine, a nearly constant electric power supplied to the pump. The delivery rate then adjusts depending on the aforementioned operating conditions. The particular advantage of this type of control is that reliably always a uniform or at least almost uniform delivery of the liquid is achieved, whereby an unpleasant noise or even alternating surge-like Flüssigkeitsaustragungen be avoided from the drain hose end. Furthermore, an overload of the pump is avoided, for example at small flow rates, low pump-out levels or idle, so when air is sucked in and a so-called ventilation takes place. The above regulation thus provides a constant or at least almost constant power value for the absorbed electric power of the pump motor, at different loads on the rotor.

The control device of the pump device is configured to supply the motor with an at least almost constant electrical power or current at a fixed, almost constant or constant value with a deviation in the range of + -20% by means of the power stage. Preferably, the deviation is limited to a range of + - 10%. Here, the fact is taken into account that a small inaccuracy can be accepted in order to provide the power stage and the control device with extremely simple and inexpensive components. Furthermore, no particularly high demands are placed on the engine.

Overall, the value is set such that a standard-compliant flow rate is achieved at a predetermined maximum Abpumphöhe. In the case of washing machines, for example, a maximum pumping height of 1.8 meters is permitted, whereby a minimum volume flow, for example 10 l / min, must be conveyed under all conditions and pumping heights between 0 and 1.8 meters. The power stage or the control device is dimensioned so that an almost constant to constant electric power or current is supplied to the pump, such that the minimum permitted volume flow is achieved at the maximum pumping height.

Overall, it is expedient that the control of the pump is independent of the self-adjusting speed of the impeller. This means that the speed adjusts itself independently of the supplied power and of the mechanical or hydraulic resistance acting on the impeller, without it having to be detected by the control device or otherwise evaluated. This makes the control circuit very simple and reliable to operate. Sensors, such as sensors for speed detection or rotation angle detection are not necessary.

In an expedient development, the control device is set up to limit the rotational speed of the rotor to an upper limit value and / or a lower limit value, as a result of which a mechanical overloading of the engine due to excessive rotational speeds is avoided. In addition, the lower speed value monitoring ensures that safe and even delivery takes place in the lower speed range. The supplied power is at least temporarily increased for this special case. For a pump device for pumping liquid from the treatment tank, it is appropriate that the pump has a rated power in the range of 5W to 100W, preferably 10W to 20W or to use a pump with the said rated power.

As a motor type for driving the pump is doing a DC motor, single-phase AC motor or multi-phase AC motor into consideration. The power level is adapted to the motor type used, wherein for the single-phase AC motor or for the polyphase AC motor, a suitable for the motor used frequency converter for commutation is used.

The invention further relates to a water-conducting device, such as a washing machine with a tub for holding washing liquid for treating laundry, a horizontally rotatably mounted drum in the tub, a motor for rotating the drum, a radiator, a drain device comprising a pump device as mentioned above, which is in fluid communication with the tub and is designed for pumping or flooding of washing liquid.

Thus, the pump operation can be selectively adjusted or regulated to a narrow range based on the detected parameters with respect to recorded electrical power, regardless of the load acting on the pump, so further increasing the effectiveness is achieved.

The invention further relates to a dishwasher with a washing container for receiving items to be washed, such as crockery or cutlery, further comprising a Umfluteinrichtung and / or a drain device with a pumping device as mentioned above, which is in fluid communication with the washing and is set up , at least temporarily to promote rinsing liquid from the lower region of the washing container in the upper region, based on the operating position of the dishwasher Aufstellposition, and / or to pump out the rinsing liquid from the washing out.

Fig. 1:

eine Waschmaschine in einer skizzierten Schnittdarstellung;

Fig.2:

die Waschmaschine in Aufstellposition (schematisch);

Fig.3a - 3c:

das Verhalten des Pumpenmotors in Diagrammen und

Fig. 4:

die Pumpeinrichtung schematisch in einer bevorzugten Ausführung.

An embodiment of the invention is shown purely schematically in the drawings and will be described in more detail below. Show it

Fig. 1:

a washing machine in a sketched sectional view;

Figure 2:

the washing machine in set-up position (schematic);

3 a - 3 c:

the behavior of the pump motor in diagrams and

4:

the pumping device schematically in a preferred embodiment.

In Fig. 1 is a purely schematic representation of a washing machine 1, shown with a trained as a tub 2 treatment tank. The position and direction information refer to the operational installation position of the washing machine 1. Within the tub 2 a rotatably mounted and driven by an electric motor 13 drum 3 is arranged, which moves the laundry items located in the tub 2 8. The drum 3 is made in the present embodiment of stainless steel and provided with a plurality of openings for the flooding. The housing 4 has a loading opening 9, via which the interior of the drum 3 can be reached through the sealing sleeve 6. The loading opening 9 can be closed by means of a door 5. In the lower region of the tub 2, a radiator 7 is arranged, which can heat the washing liquid in the tub. In the upper part of the machine 1, an inlet valve 15 is sketched, which provides the running in of the water from the supply network. About the Einspülkasten 11, the water is passed through the connecting pipe 14 in the tub 2, wherein in the dispenser 11 entered detergent is flushed into the tub 2. Below the tub 2, a drain device 12 is arranged, which leads the spent washing liquid or the rinse water from the tub 2 to the drain line 12c, which usually opens into a sewer. The control device 18 controls the inlet valve 15, the activity of the drainage device 12, the drive motor 13, which is energized via the power unit or a frequency converter 16, and the radiator 7. In the lower part of the tub 2, based on the Bertriebsgemäße installation position of the washing machine 1, is the pump 17a mounted in a flooding device. The pump 17a is connected to the drain pipe 12b on the inlet side and suction side, respectively, and can convey the washing liquid 19 therein through the pipe 17b into the upper portion of the tub 2 and the drum 3, respectively. The washing liquid 19 is injected or flows onto the laundry items 8 through the nozzle or the outlet 17c.

In Fig. 1 is also shown that the level of the washing liquid 19, the heating element 7 just covered with washing liquid, so that no dry heating takes place. Below a minimum level there is a risk that the circulating pump 17a can no longer completely draw in liquid, so that increased noise can occur. The monitoring of the level takes place with a sensor 20, which detects the conductivity of the liquid or is designed as a pressure sensor.

In Fig. 1 is also shown schematically that the pumps 12a and 17a each include an electric motor 12d, 17d, which serves to drive the pump 12a, 17a. In In this example, both the motor 12d of the drain pump and the motor 17d of the bypass pump 17a are energized by the frequency converter 16. The frequency converter 16 is in operative connection with the control device 18, so that the control device 18 transmits to the frequency converter 16 via a signal connection the specifications as to when the respective pump or the respective pump motors 12d, 17d should be activated.

Fig. 2 schematically shows the water-bearing device 1 with the mounted below the treatment tank 2 pump 12a with pump motor 12d. Depending on the installation situation of the device 1, the discharge hose 12a is mounted on the pump and can end in different heights. The pumping height h is measured here from the installation surface of the device, which approximately corresponds approximately to the position of the pump 12c in the device 1. at least the local deviation is irrelevant to the scheme.

In the Fig. 4 is exemplified a pumping device with a frequency converter 16 for energizing the pump motor 12d sketched. Since the frequency converter 16 is matched with respect to its dimensioning to the motor 12d or to the winding parameters, this combination can be referred to as a mechatronic system. The applied to the input of the inverter 16 supply voltage 25 (for example, 230V ~) is rectified with a rectifier 26 into a DC voltage with a positive pole 29 and a negative pole 28. The DC voltage in the DC intermediate circuit 27 is in this case in the range of 300V to 350V, or at 325 V, wherein sets in the DC voltage intermediate circuit 27, the current IDC. For other values for the supplied supply voltage 25, other values for the rectified voltage in the DC intermediate circuit 27 would accordingly be set. At the DC voltage intermediate circuit 27, the inverter 32 is connected, each of which has a so-called half bridge 34u, 34v, 34w for each phase U, V, W of the motor. The half bridges 34u, 34v, 34w switch the motor current IU, IV, IW in the phases U, V, W by means of transistors T1 to T6, using a pulse width modulation which is used to provide sinusoidal currents IU, IV, IW or direct currents in the phases U, V, W is used. As a motor 12d, a 3-phase motor with a 3-strand stator winding 36 is used in this example, which is designed star-shaped. In the DC intermediate circuit 27, the microprocessor controller 31 adapted to drive the half-bridges 34u, 34v, 34w in response to the detected values to energize the individual windings 36u, 36v, 36w for the operation of the motor 12d is such that a rotating field and rotates the rotor 33 with the impeller attached or coupled thereto. The frequency converter 16 further comprises for the individual phase currents IU, IV, IW respectively a detection device 35u, 35v, 35w, which forwards the phase currents as a signal to the microprocessor control 31, so that they Half bridges 34u, 34v, 34w can control accordingly. At least one of the detection means 35u, 35v, 35w or two or all three are further arranged to supply the power IU, IV, IW supplied as a measure of the power or the individual windings 36u, 36v, 36w as signal MU, MV, MW Supply microcontroller 31.

The respective detection devices 35u, 35v, 35w comprise, in a simple embodiment, a voltage divider in order, in conjunction with an amplifier or operational amplifier, to obtain a signal MU usable by the microcontroller 31. MV to generate MW. The microcontroller 31 further comprises a memory 31 a and cooperates with this, which includes a computer program PROG for processing by the microcontroller 31 to the function of the frequency converter 16 by appropriately driving the half-bridges 34 u, 34 v, 34 w and the function of the device for Detecting the frequency converter 16 supplied supply current or a possible heating to provide.

• Die Leistungsregelung kann für die Ablaufpumpe 12a wie folgt realisiert werden, gleiches ist auch für die Umflutpumpe 17a anzuwenden und ist anhand der Diagramme 3a bis 3c verdeutlicht.

The microcontroller uC of the control device 31 is programmed by means of the program PROG so that a controller or control circuit for the power supply to the motor windings 16 is provided. This is explained in principle as follows:

• The capacity control can be realized for the drain pump 12a as follows, the same applies to the bypass pump 17a and is illustrated with reference to the diagrams 3a to 3c.

The output from the frequency converter 16 to the motor 12 d, power may, for. B. by a current measurement and the output pulse pattern (as a substitute for a voltage measurement) can be determined. If the losses in the motor 12d are neglected, the electrical input power of the motor 12d is equal to the mechanical shaft power output by the motor 12d. Instead of controlling the motor 12d to a constant speed n of the rotor 33, the speed n is continuously changed so that a constant power p is established. For this purpose, nominal and actual power are compared continuously or quasi-continuously. The difference is fed to a controller which changes the speed n so that the desired setpoint power is set. This controller can also have other subordinate control loops.

The result is a delivery rate linked to the mechanical performance of the engine as follows: $$\mathrm{P\_mech}-\left(\mathrm{p\_g}\left(\mathrm{H}\right)+\mathrm{p\_R}\right)*\mathrm{VS}=\mathrm{P\_f}\ddot{\mathrm{O}}\mathrm{rder}=\mathrm{p}*\mathrm{VS}$$

• abgegebene mechanische Wellenleistung (P_mech)
• Förderleistung der Pumpe (P_förder)
• geodätische Höhe (h)
• Druck durch geodätische Höhe (p_g(h))
• Volumenstrom (VS)
• Druckverluste durch Reibung des Mediums an den Schlauchwandungen (p_R)

The formula symbols mean:

• delivered mechanical shaft power (P_mech)
• Delivery rate of the pump (P_förder)
• geodesic height (h)
• Pressure due to geodetic height (p_g (h))
• Flow rate (VS)
• Pressure losses due to friction of the medium at the hose walls (p_R)

Somit wäre die abgegebene mechanische Leistung proportional zur Förderleistung. Über eine definierte Abgabeleistung würde sich abpumphöhenunabhängig immer derselbe Volumenstrom einstellen.If the pressure loss due to the geodetic height h and the pressure loss due to friction were not present, then the following would apply: $$\mathrm{P\_mech}=\mathrm{P}\mathrm{\_}\mathrm{f}\mathrm{ö}\mathrm{rder}=\mathrm{p}*\mathrm{V}\mathrm{S}$$

Thus, the output mechanical power would be proportional to the capacity. Over a defined output power, the same volume flow would always be set independently of the pumping height.

gegeben, dann ist der Einfluss vernachlässigbar. Diese Bedingung ist in einem serienmäßigen Waschautomat nur annähernd erfüllt. Jedoch ist die Abpumphöhenabhängigkeit des Volumenstroms bei Regelung auf eine konstante Leistung deutlich geringer als bei Regelung auf eine konstante Drehzahl.The disturbing influence of the pressure p_R can be avoided by taking it into account as a constant, since it is not dependent on the pumping height.
Furthermore, there is the influence of pressure from geodetic height h, which is dependent on the pumping height. Since the pumping height h is not known, this pressure can not be calculated. But it is $$\mathrm{p\_g}\left(\mathrm{H}\right)*\mathrm{VS}<<\mathrm{P\_mech}$$

given, then the influence is negligible. This condition is only approximately fulfilled in a standard washing machine. However, the Abpumphöhenabhängigkeit the flow rate is controlled at a constant power significantly lower than when controlling to a constant speed.

As a further development or improvement of the just explained power control, the torque control or current control can be considered. The goal here is to keep the shaft torque approximately constant.

The mechanical shaft power of the pump 12d is calculated from: $$\mathrm{P\_mech}=\mathrm{M\_mech}*\mathrm{2}*\mathrm{\pi }*\mathrm{n}$$

Advantage 1: In the reduction of the pumping height h, and thus the reduction of the pressure p_g (h) and the concomitant reduction of Drehzah nl, with constant shaft torque M_mech must decrease the mechanical power P_mech; although the Volume flow VS is still increasing. However, the increase in the volume flow VS does not take place to the extent that happens in the power control.

Advantage 2: It is also advantageous that the ohmic losses of the motor 12d remain constant, and not, as in the power control, increase. This has advantages in winding heating.

The regulation of the shaft torque, ie of the rotor 33, can be realized in a drive system or pump device, comprising a frequency converter 16 and permanent magnet motor 12d, via the torque-forming portion of the current. For this purpose, the stator current isq, which is transformed into a coordinate system rotating with the rotor 33 of the machine 12d, is used as the controlled variable. This is proportional to the active current of the motor 12d.

During the pumping down the water column is continuously reduced until it is degraded so far that the impeller coupled to the rotor 33 not only promotes water, but it begins to promote air. This is called slurping. The slurping is audible and therefore avoid as possible. The load-controlled pumping described above can be combined with a Schlürfsensierung described below.

If sludging occurs during load-controlled pumping, the absorbed power P first breaks down. Since it is controlled at a constant power / torque / current, the control would accelerate the drive 12d. If a maximum speed n is defined up to which it is allowed to accelerate, then reaching the speed n is a sure sign for snare operation and it can be switched off. Due to the high acceleration of the rotor speed n of the motor 12d in the pump 12a, this would be done very quickly.

The in Fig. 3a to 3c said sequence is suitably suitable for the operation of a circulating pump 17a with the pump motor 17d, when, for example, the circulating operation is provided in a washing machine.

Furthermore, the pump device can be used in a dishwasher corresponding to the flooding with a circulating pump 17d and / or for pumping with drainage pump 12d.

3a shows a diagram of the behavior of the supplied electric power P of the motor 12d as a function of the pumping height h. It can be seen that the supplied power P is constant, for different pumping heights. In this example, the power p is set to 13W. The control can also be designed so that adjusts a slightly increasing power with increasing Abpumphöhe, so for example at h = 0m a value of 11W and at the maximum specified height h = 1.8m 13W. The Other values, ie speed n and volumetric flow VS, may likewise deviate slightly compared to the behavior explained below.

Fig. 3b shows the adjusting itself in the pump 12a or drain hose 12c flow rate VS as a function of Abpumphöhe h. It can be seen that at a pumping height h of 0 meters, a first maximum flow rate VS, in this example of about 21 l / min, sets, and this steadily drops with increasing pumping height h. For all pumping levels, up to the limit value hg, a predetermined minimum limit value VSg for volume flow VS is maintained here. In the example shown, the given volume flow VSg of 10 l / min is exceeded with a limit value of 1.8 m, since in this example a volume flow VS of 12 l / min is established.

Fig. 3c shows the speed behavior of the impeller or the rotor 33 of the pump. At the lower value of the pumping height h of 0 meters, a rotational speed n of 2000 rpm is established, whereby at this rotational speed n the maximum volume flow VS for this height, for example 21 l / min, is set. At the upper limit of the pumping height of 1.8 meters, an increased speed n sets in, here just under 2800 rpm to exceed the volume flow VSg. In the example shown, the volumetric flow VS at a pumping depth of 1.8 m is 12 l / min and thus certainly exceeds the limit value VSg of 10 l / min prescribed by a standard. It can also be seen that, starting at a mean pumping height, here h = 1 m, the rotational speed n increases more sharply than in the lower range of the pumping height h between 0m and 1 m.

Claims (10)

1. Pump device for a water-conducting appliance (1) such as a washing machine or a dishwasher having a treatment container (2) for receiving washing liquid (19) for treating items to be treated (8) within the treatment container (2), which device is intended to pump out or circulate washing liquid (19), the water-conducting appliance (1) having a maximum admissible pump-out height hg, said device comprising a pump (12a, 17a) having an electric motor (12d, 17d) and a rotatable pump wheel for conveying the liquid (19), which pump is connected to a power stage (16, 32) controlled by means of a control device (31) in order to control the flow rate VS, the control device (31) being designed to detect electrical parameters supplied to the pump (12d, 17d) or the motor, and to influence the supply of the electrical power or current to the motor (12d, 17d) on the basis of these parameters,
   characterised in that
   the electrical power or current taken up by the motor (12d, 17d) is used as the electrical parameter, the control device (31) being designed to control, by means of the power stage (32) and on the basis of the detected parameters, the electrical power (P) or current supplied to the motor (12d, 17d) irrespective of the rotational speed (n) of the pump wheel which is established, such that a predetermined electrical power (P) or current having a specified value is established with a deviation in the range of +-20 %, such that the maximum admissible pump-out height hg reaches at least a predetermined minimum volumetric flow rate VSg.
2. Pump device according to claim 1,
   characterised in that
   the control device (31) is designed, by means of the power stage (32), to supply the motor (12d, 17d) or the windings of the motor (36u, 36v, 36w) with electrical power (P) or current having the specified value with a deviation in the range of +-10 %.
3. Pump device according to either claim 1 or claim 2,
   characterised in that
   the control device (31) is designed to limit the rotational speed of the pump wheel to an upper limit value and/or a lower limit value.
4. Pump device according to any of claims 1 to 3, wherein
   the motor (12d, 17d) of the pump (12a, 17a) has a nominal power in the range of from 5 W to 100 W, preferably from 10 W to 20 W.
5. Pump device according to any of claims 1 to 4, wherein
   the pump (12a, 17a) comprises a DC motor.
6. Pump device according to any of claims 1 to 4, wherein
   the pump (12a, 17a) comprises a single-phase AC motor, wherein the power stage (32) is designed as a part of a frequency converter (16).
7. Pump device according to any of claims 1 to 4, wherein
   the pump (12a, 17a) comprises a dual-phase or multi-phase rotary current motor (12d, 17d), wherein the power stage (32) is designed as a part of a dual-phase or multi-phase frequency converter (16).
8. Pump device according to any of claims 1 to 8, wherein
   the maximum pump-out height is 1.8 m and the minimum volumetric flow rate VSg is 10 l/min.
9. Washing machine (1) comprising a suds container (2) for receiving washing liquid (19) for treating laundry (8), a drum (3) which is horizontally rotatably mounted in the suds container (2), a motor (13) for rotating the drum (3), a heating element (7) and a discharge device (12) comprising a pump device (12d, 17d, 16) according to any of claims 1 to 8, which device is fluidically connected to the suds container (2) and is designed to pump out or circulate washing liquid (19).
10. Dishwasher comprising a washing container for receiving washware such as crockery or cutlery, further comprising a circulation device and/or a discharge device comprising a pump device (12d, 17d, 16) according to any of claims 1 to 8, which device is fluidically connected to the washing container and is designed to at least intermittently convey rinsing liquid from the lower region of the washing container into the upper region, with respect to the operational set-up position of the dishwasher, and/or to pump the rinsing liquid out of the washing container.

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