Water Pump for Bodies of Water Containing Suspended Particles

Abstract

A water pump for bodies of water such as ponds, aquariums, or fountains containing suspended particles has a housing with a pump housing part provided with an intake opening and an exit opening, in which housing part an impeller with a shaft is rotatably supported, and a motor housing part in which an electric motor is received. As an improvement, an electronically commutated motor is used and the pump has a power input as well as power and control electronics for the motor having an operating state detection device with speed detection, processor and data storage device. The processor can control an interrupt switch between the power input and the motor. In the data storage device certain characteristic lines in regard to normal operating states can be stored.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and details result from the dependent claims and the embodiments of the invention illustrated in the drawings which will be explained in the following. It is shown in:

FIG. 1 schematically a pump according to the invention;

FIG. 2 a diagram with pump characteristic lines and operating states; and

FIG. 3 a diagram with speed characteristic lines of the pump.

DESCRIPTION OF PREFERRED EMBODIMENTS

The water pump illustrated in FIG. 1 has a housing 1 that is subdivided into a pump housing part 2 and a motor housing part 3. The pump housing part 2 has an intake opening 4 functioning as a water intake and an exit opening 5 serving as a water outlet. In the pump housing part 2 an impeller 8 is arranged on a rotatable shaft 9. The shaft 9 extends from the pump housing part 2 into the motor housing part 3 and into an EC motor arranged therein. The EC motor has a rotor 14 fixedly connected to the shaft 9 and a stator 12 surrounding the rotor. Preferably, the rotor 14 is of a two-pole configuration and the stator 12 is of a six-pole configuration (or a two-pole configuration with protective extra-low voltage). The shaft 9 is supported in an end shield 10 that shields the motor mechanically relative to the pump housing part 2 and the impeller 8.

In the pump housing 1 control and power electronics 16 are provided which preferably are arranged also in the motor housing part 3 and thus at a spacing from the water-conveying parts. Included is also a schematically indicated microprocessor 17 that can actuate an interrupt switch 21 by means of a control line schematically indicated by arrow 19. In this way, the electric supply between the electric power input 26 of the pump, that is connected to a electric cable 36, and the power electronics 16 and thus the motor can be interrupted. In FIG. 1, the interrupt switch 21 is illustrated in the activated position, i.e., current flow is interrupted and the motor is switched off. The illustration of the interrupt switch 21 is only schematic. Of course, not only a mechanical switch but also in particular electronic switches can be utilized.

The entire electronic device including power electronics 16, microprocessor 17, and interrupt switch 21 can be potted so as to be watertight for safety reasons. This holds true also for the stator 12 of the motor. Inasmuch as stator 12 and rotor 14 are separated by a so-called split cage, preferably the entire free motor housing part can be potted to be watertight.

The pump according to the invention is utilizable in a plurality of ways when in the date storage device information in regard to a normal operating state of the pump is stored. This can be in particular the conventional pump characteristic lines and/or rotary speed characteristic lines. For an optimal control a software is to be provided in the electronics which software performs a nominal/actual value comparison between the stored normal operating state data and the detected actual operating state of the pump detected by the operating state detection device. Upon surpassing a preset difference between these two values, which preset difference is also stored within the data storage device, a change of the operating state of the pump is to be initiated by means of the control device. This change can be, for example, lowering of the speed of the pump or switching off of the pump by activation of the interrupt switch 21.

As a result of the speed detection, the pump cannot only comprise control electronics but also governing electronics without significant further material expenditure which governing electronics ensure by a closed-loop control circuit that the target speed of the pump is indeed achieved and maintained. In this connection, the speed is continuously detected, compensated, and possibly adjusted. This is done, for example, in that the permissible and preset difference for the nominal/actual value comparison between normal operating state and actual operating state is set to be very low.

The application possibilities and the function of the pump according to the invention can be explained particularly well with the aid of the diagrams of FIGS. 2 and 3.

FIG. 2 shows the water flow rate in liters/minute plotted against the pressure or the height in meters that must be overcome by the water with the aid of the pump. The light-colored line 61 is the characteristic line 61 (state 1) provided by the manufacturer for the height plotted against flowrate on which characteristic line the pump operates in the normal operating state. However, the pump is also able or capable of providing higher power up to a maximum characteristic line 62 (state 2). Additionally, FIG. 2 illustrates two device characteristic lines 63, 64. The lower device characteristic line 63 represents the proper use of the pump in a normal device in which the pump is usually utilized and for optimal free conduits and filters, i.e., for a device that as a whole is clean. The pump then operates generally at the operating state point A.

The upper steeper device characteristic line 64, on the other hand, shows possible operating points of the total device when filters are clogged, the device as a whole is soiled or higher pressures must be overcome for other reasons. In this case or, for example, in the case of a clogged filter, the operating state of the pump moves from point A along the normal characteristic line 61 to the operating state point C. In this connection, the pump no longer achieves the desired flow rate Q; the flow rate drops. By means of the software-supported pump control in such a case the operating state of the pump is moved upwardly along the device characteristic line 64 until the initial and desired flow rate is reached. This is the case at the illustrated operating state point A′. The flow rate of the pump can be increased maximally until the maximum characteristic line 62 is reached.

The pump therefore can automatically adjust the desired operating state and maintain the flow rate Q at a constant rate, for example, in the case of a filter that slowly becomes clogged, over a long period of time without the operator of the pump having to continuously adjust the pump operation himself.

The control is optimized in that in the data storage device different pump characteristics lines and speed characteristics lines are stored already at the time of delivery of the pump. The pump can therefore automatically react to changes of the device characteristic line and perform a readjustment to the set output.

In analogy to the determination of the flow rate based on the diagram of FIG. 2, the speed of the pump in different operating states can be taken from the diagram of FIG. 3. Numeral 61 indicates again the standard characteristic line and 62 indicates the maximum pump characteristic line.

The described operating state detection technology is utilized also for dry running and blocking protection. In the case of dry running of the pump, i.e., when the pump takes in no water, the pump has no resistance and therefore rotates at very high speed without any flow; this is indicated by operating state point T. The point T is above the maximum characteristic line 62. This is recognized by the pump by means of the speed detection and the interrupt switch 21 will be activated. However, in order to prevent in the case of a brief period of dry running, for example, if not enough water is present in the pump sump, an immediate power-off of the pump, the software comprises a predetermined program that first causes one or several speed changes of the pump before the pump is switch off. Such a program can lower the engine speed, for example, once or several times, to the operating point P. An example of such a program course is as follows:

2 seconds operating point T. 2 seconds operating point P 2 seconds operating point T. 2 seconds operating point P, 2 seconds operating point T. power off.

During the course of this program pass, the pump has the possibility, for example, if the pump sump is not filled sufficiently, to take in the required quantity of water for its operation. In this way, there is a flow rate Q and the operating point moves on the standard characteristic line 61. When during the program pass it is detected that the standard operating state is reached, the software is to be designed such that the program is stopped because switching off of the pump is no longer required.

Such a program can advantageously be used also as a self-test of the pump. When at the time of purchase the pump is connected to a power supply without water being present, the pump runs the afore described program and powers off at the end of the program. The buyer can therefore hear that the motor of the pump is intact.

When the pump is blocked, for example, in the case of a complete clogging, the opposite of a dry run occurs. In the case of blockage, the speed is reduced to zero at the indicated operating point B. This operating point B is significantly below the minimal desired nominal characteristic line 61 so that this state is detected by the electronic device as a blockage and the pump is switch off.

The pump according to the invention can therefore be used in different operating states without the operator having to perform his own adjustments. As described, an automatic self-test can be provided so that even at the time of purchase the function of the pump can be demonstrated plausibly.

The specification incorporates by reference the entire disclosure of German priority application 10 2006 041 317.2 having a filing date of Sep. 1, 2006.

While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A water pump for bodies of water containing suspended particles, the water pump comprising: a housing comprises a pump housing part provided with an intake opening and an exit opening and further comprising a motor housing part;an impeller with a shaft arranged in the pump housing part so as to be rotatable;an electric motor arranged in the motor housing part, wherein the electric motor is an electronically commutated motor;a power input;power and control electronics for the electric motor comprising an operating state detection device with speed detection, a processor, and a data storage device.

2. The water pump according to claim 1, further comprising an interrupt switch controlled by the processor and arranged between the power input and the electric motor.

3. The water pump according to claim 1, wherein information in regard to at least one normal operating state of the water pump are stored in the data storage device.

4. The water pump according to claim 3, wherein the information comprises at least one of a pump characteristic line and a speed characteristic line.

5. The water pump according to claim 3, comprising a software that carries out a nominal/actual value comparison between a stored standard operating state data and an actual operating state of the water pump detected by the operating state detection device, wherein the software initiates a change of the actual operating state when a preset difference for the nominal/actual value comparison is surpassed.

6. The water pump according to claim 5, wherein the change of the actual operating state consists of running a predetermined program with speed change of the water pump.

7. The water pump according to claim 6, wherein, when the standard operating state is reached again during the program pass, the program is stopped.

8. The water pump according to claim 6, wherein the change of the actual operating state resides in an activation of an interrupt switch or in ending the program.

9. The water pump according to claim 1, wherein the power and control electronics comprises governing electronics governing a predetermined speed.

10. The water pump according to claim 1, wherein the power and control electronics are arranged in the motor housing part and are water-tightly potted.