EP0610569B1 - Electric pump for delivering water in household appliances - Google Patents

Description

The invention relates to an electrically driven pump for pumping water in household appliances with a pump chamber having a membrane and a piezo-electric oscillating body attached to the membrane, the pump chamber having an inlet on which a check valve closing in the direction of the reservoir is formed Water-fillable reservoir and connected to a consumer via an outlet, the reservoir being at a higher level than the pump chamber and the check valve, on the one hand, blocking the connection from the reservoir to the pump chamber when there is excess pressure in the pump chamber, so that liquid flows through the outlet is supplied to an outlet opening (transport phase), and on the other hand opens at excess pressure, so that liquid can flow into the pump chamber via the reservoir (suction phase).

A pump of the specified type is known for example from JP 62-142597 A2. The known pump is used in a steam iron to convey water from a reservoir into a steam chamber which is formed in the sole body of the steam iron. In order to prevent the reservoir from leaking when the pump is at a standstill, the known pump has an outlet valve, the valve element of which is held in a closed position by a spring. The disadvantage here is that the pump must operate continuously against the opening pressure of the outlet valve during operation, this opening pressure cannot be kept arbitrarily small due to inevitable manufacturing tolerances and varies from pump to pump. Obtained on average this results in significant power losses, which have a negative impact on the required drive power and the associated noise development of the pump.

The invention has for its object to provide an electrically driven pump of the type mentioned, which is characterized by a minimal drive power and very low operating noise with little effort.

This object is achieved by the characterizing features of claim 1. In the pump according to the invention, a riser pipe is provided instead of a tightly closing outlet valve, the mouth of which as an outlet opening or overflow lies above the level of the maximum fill level of the storage container and thereby prevents the storage container from being emptied unintentionally. This has the advantage that the back pressure to be overcome by the pump always corresponds only to the difference between the level of the outlet opening and the level of the fill level in the storage container. Thus, the pump alone has to overcome the delivery head and not additionally the opening resistance of an outlet valve, which for technical reasons has to be significantly larger. Accordingly, the energy requirement of the pump according to the invention is significantly lower.

Characterized in that during the suction phase predominantly only in the area of the check valve and less in the area of the outlet of the pump chamber, a check valve blocking in the direction of the pump chamber at the outlet or in the line from the pump chamber to the consumer can be dispensed with. This effect is based on the fact that the vibration waves emanating from the membrane only appear at the check valve before they reach the outlet because of the longer way. Water can also flow into the pump chamber via the outlet in suction operation, but water always flows through the non-return valve into the pump chamber, the amount of which, even if it is so small as the delivery head increases, is subsequently supplied to the consumer in the transport phase .

When the reservoir is filled, the outlet opening of the riser is at approximately the same level as the water level in the reservoir, so that the pump has to overcome practically no delivery head. The pump can draw in most of the water via the check valve and deliver it to the consumer. If, on the other hand, the storage container has a very low filling level, the pump must overcome the head between the low filling level in the storage container and the outlet opening of the riser. Although the intake volume of water via the check valve is lower, this volume - however small it may be - is forcibly returned to the consumer during the transport phase. Only when, according to the invention, a vacuum is generated at the check valve so quickly and earlier in the suction phase before it has reached the outlet - and this is achieved by a rapidly reciprocating membrane by means of the piezoelectric vibrating body - flows Water from the reservoir into the pump chamber, which is then supplied to the consumer in the transport phase.

In order to achieve adequate pump performance or to increase it, various parameters of the pump depend on one another according to the invention. For example, the pump performance also depends on whether a certain spatial allocation of diaphragm and check valve is observed, ie whether certain distances between them are not exceeded or undershot, so that the vibration waves first hit the check valve and open this for sucking in water before they reach the outlet. Furthermore, the pump performance depends on how and where the outlet is arranged and how large its flow cross-section is in relation to the size of the membrane and the check valve. Particularly good results are achieved when the membrane with the piezoelectric vibrating body is directly opposite the check valve and is at a relatively short distance from the check valve. It is advantageous if the membrane with the piezoelectric vibrating body and the check valve lie approximately on a common axis that is perpendicular to these parts.

The pump capacity can also be increased if the opening cross section of the inlet at the check valve is larger than the outlet cross section at the outlet. A further increase in pump performance is also achieved if the outlet is located further away from the check valve in the pump housing than the check valve from the membrane.

Increasing the frequency on the piezoelectric vibrating body also leads to faster movement of the membrane, which also has a favorable effect on better pump performance. If the frequency of the membrane is close to the resonance frequency of the valve, the pump performance is good. A larger amplitude, i.e. a larger stroke of the membrane, also leads to better pump performance.

Due to the low performance of the pump according to the invention, which is also desired in many areas of application, and the lack of a Exhaust valve, a very low operating noise is achieved with the pump. It is also advantageous that when the pump is switched off, there can be no unwanted leakage of the water in the reservoir for consumption, as is possible with a recurring leakage at the outlet valve in the known pumps, for example as a result of contamination on the valve seat if there is no climbing performance. The manufacturing costs of the pump according to the invention are also low due to the few and relatively small components.

If, according to the features of claim 2, a ventilated overflow advantageously connects with a dropping delivery line branching off from it, this prevents water transport when the piezo element is not in operation, that is, water cannot be sucked in via the downpipe .

According to the features of claim 3, a pump control is achieved in a simple manner, so that the amount of water to be supplied to the consumer can be reduced or increased depending on the application.

According to the development according to the features of patent claim 4, the valve can be installed particularly easily since the area of the overflow lying above the maximum fill level is more easily accessible from the outside or from above.

The features of claim 5 prevent overflow from overflow by means of the opening when the pump or, respectively, pumps more water than can be supplied to the consumer.

By designing the pump according to the features of the claim, it is possible to connect a pole of the piezoelectric vibrating body to the electrical power supply via the membrane, thereby simplifying the construction and assembly of the vibrating body. The insulating film also protects the membrane against corrosion.

According to the features of claim 7, the inlet valve can consist, according to the invention, of an extremely thin-walled disk made of elastically deformable material, which is pivotally attached to the wall of the pump chamber on one side. This makes it very small. It is advantageous that the disk of the inlet valve covers the inlet opening, that the disk has a part-circular cut and that the area enclosed by the cut is formed by a valve flap that can be lifted off the inlet opening. Such an embodiment of the inlet valve can be produced simply and inexpensively, for example by cutting it out of a film, which can then be easily connected to the wall of the pump chamber by gluing. The opening resistance of the valve flap can be kept very low with the help of the film and valve noise is avoided due to the elasticity of the film material. At the same time, the valve flap rests on the valve seat in an elastically sealing and automatically resilient manner.

A greater pump performance with low operating noise is achieved by the features of claim 9. An increase in the pump output results from the features of claim 10. Such a check valve can be opened without any appreciable resistance and does not cause any perceptible operating noise.

Because of its simple construction, its small size and its low operating noise, the pump according to the invention can advantageously be used in a number of electrical devices. An advantageous application is given when installing the pump in a steam iron (Claim 11), the pump being attached to the bottom of the storage container and connected to an overflow arranged to the side of the storage container, and the delivery line of the pump being connected to the steam chamber in the soleplate of the steam iron is. This ensures an even supply of water to the steam sole that is independent of the water level in the storage container, and the water flow is effectively stopped when the iron is switched off. The pump also makes it possible to regulate the steam generation by controlling the operating frequency, the operating voltage or the respective duty cycle and to optimally adapt it to the type of fabric to be ironed.

It is also advantageous to use the pump according to the invention in a device for preparing hot drinks (Claim 12), in that the pump is arranged between the outlet of the water storage container and the inlet of a water heater. The pump can be controlled in relation to the heating capacity of the instantaneous water heater so that a brewing temperature of approx. 90 ° C is reached. Steam generation is not necessary since the pumping of the water is effected. This reduces boiling noises and the calcification of the instantaneous water heater is considerably reduced. Furthermore, the use of the pump enables a better time-dependent control of the water supply to the extraction filter and thus a targeted taste regulation. Since steam is not generated, it can no longer damage and discolour plastic parts.

Another advantageous use of the pump according to the invention is given in a squirt bottle (claim 13), the pump chamber being arranged under the bottle bottom and being connected to the bottle neck, which carries a spray head, by a riser pipe penetrating the bottle bottom. Such an electrically operated wash bottle can be used, for example, for moistening laundry before ironing, as a hair humidifier or for removing wallpaper. Further applications of the pump according to the invention are conceivable, especially in the food sector for conveying beverages.

Fig. 1

einen Querschnitt durch eine Pumpe mit einer Membran und einem Schwingkörper,

Fig. 2

eine Ausführungsform für ein Einlaßventil,

Fig. 3

einen Querschnitt durch eine Pumpe mit zwei gegenüberliegenden Membranen und Schwingkörpern,

Fig. 4

eine Explosionsdarstellung einer Pumpe mit einem im Auslaß angeordneten Rückschlagventil,

Fig. 5

eine schematische Darstellung des Einbaus einer Pumpe gemäß Figur 1 in einem Dampfbügeleisen,

Fig. 6

eine schematische Darstellung des Einbaus einer Pumpe gemäß Figur 3 in einer Kaffeemaschine,

Fig. 7

einen Querschnitt durch eine Spritzflasche mit einer er findungsgemäßen Pumpe zur Förderung des Flascheninhalts und

Fig. 8

einen Querschnitt durch den Überlauf nach Fig. 5 in vergrößertem Maßstab, wobei allerdings zusätzlich noch im Überlauf ein Ventil und eine Öffnung zum Wassertank hin integriert sind.

The invention is explained in more detail below on the basis of exemplary embodiments which are illustrated in the drawing. Show it:

Fig. 1

a cross section through a pump with a membrane and a vibrating body,

Fig. 2

an embodiment for an inlet valve,

Fig. 3

a cross section through a pump with two opposing membranes and vibrating bodies,

Fig. 4

2 shows an exploded view of a pump with a check valve arranged in the outlet,

Fig. 5

2 shows a schematic illustration of the installation of a pump according to FIG. 1 in a steam iron,

Fig. 6

3 shows a schematic illustration of the installation of a pump according to FIG. 3 in a coffee machine,

Fig. 7

a cross section through a squirt bottle with a he inventive pump to promote the bottle content and

Fig. 8

a cross-section through the overflow of FIG. 5 on an enlarged scale, but in addition, a valve and an opening to the water tank are also integrated in the overflow.

The housing 1 of the pump shown in FIG. 1 has a flat plate 2 on which an annular housing body 3 is fastened by gluing or welding. The surface of the plate 2 surrounded by the housing body 3 is preferably circular or rectangular and at the same time forms part of the bottom of the storage container 25 according to FIG. 5. Inside the surface there is an inlet 4 in the plate 2, which can be closed by an inlet valve 5 is.

At a parallel distance from the plate 2, the housing body 3 according to FIG. 1 carries a membrane 6 to which a piezoelectric vibrating body 7 is attached. The membrane 6 consists of a thin sheet of metallic material and is covered on its side facing the plate 2 for insulation with a plastic film 48. To connect the vibrating body 7 to an electrical power supply, two electrodes 8 are provided, one of which is directly connected to the vibrating body 7 via the membrane 6. The plate 2, the housing body 3 and the membrane 6 together enclose a pump chamber 9, which is connected via an outlet 10 in the wall of the housing body 3 to a riser 11. Depending on the use of the pump, the riser 11 leads to an outlet opening 37 (FIG. 5) or to a ventilated overflow 28, each of which is above the level of the maximum fill level 27 of a storage container 25 connected to the inlet 4.

To operate the pump, the vibrating body 7 is excited to vibrate by connection to an electrical alternating voltage, as a result of which the vibrating body 7 causes the membrane 6 to vibrate. The membrane 6 carries out transverse bending vibrations, by means of which the volume of the pump chamber 9 is changed periodically and a pump effect is achieved.

Figure 2 shows an embodiment of the inlet valve 5, which is particularly suitable for the pump described due to its responsiveness and its ease of manufacture. The inlet valve 5 consists of a thin circular disk 12 cut out of a plastic film, which has a concentric cut 13 extending over a partial circle of approximately 320 °, through which a valve flap 14 is formed. The ring 50 of the disc 12 surrounding the valve flap 14 is glued to the edge 51 of the opening of the inlet 4 on the inside of the pump chamber 9 on the plate 1 such that the valve flap 14 covers the opening of the inlet 4 and with its edge 49 on the Edge 51 of the opening or inlet 4 can be placed. The valve flap 14 is very easily movable over the connection point 52 and therefore already reaches its open or closed position by the slightest flow forces, whereby it can reach the closed position through the resilient connection point 52 even without flow, but then much more slowly.

In the pump shown in Figure 3 is an annular housing body 15 are closed at each end by a membrane 6 with the vibrating body 7, so that the pump chamber 9 is delimited by two membranes 6. The inlet 4 and the outlet 10 are arranged on opposite sides in the wall of the housing body 15. The electrodes 8 of the vibrating bodies 7 are connected in parallel in the same direction. The vibrating bodies 7 are therefore excited in opposite directions by an applied alternating voltage, so that the pumping action of the two membranes 6 is added and thus a higher delivery rate of water is achieved.

The pump shown in Figure 4 consists of an annular housing body 16 with a laterally arranged inlet 17 and an inlet valve 18. An end face of the housing body 16 is closed by a membrane 6 with a vibrating body 7. To close the opposite end face of the housing body 16, a plate 19 made of elastomeric material is provided, which has an outwardly directed conical tip 53 with an incision 21 in its center. The plate 19, the housing body 16 and the membrane 6 can be connected to one another by means of a sheet metal ring 22 which surrounds the above-mentioned components and which, after its assembly, is firmly and tightly connected by bending tabs 23. In the area of the inlet 17 and the cone tip 53, the sheet metal ring 22 has recesses 24. The cone tip 53 forms a check valve 20 which can be easily pressed on and which prevents a backflow of liquid into the pump chamber 9 during the suction stroke of the membrane 6 without any appreciable increase in the flow resistance and thereby contributes to increasing the delivery rate. If such a check valve 20 is not present, the return flow at the outlet 10 during the suction stroke of the membrane 6 is brought about only by the inertia of the liquid column.

FIG. 5 shows the use of a pump 33 designed according to FIG. 1 in a steam iron. The plate 2 here forms the bottom of a storage container 25 which can be filled with water via a filler neck 26. The riser 11 leads via an outlet opening 37 to an overflow 28 which is arranged above the level of the maximum fill level 27 and which has a ventilation opening 29. A downpipe 30 branches off from the overflow 28 and is connected to a steam chamber 31 in the sole body 32 of a steam iron 54. For the steam operation of the steam iron 54 (only partially shown), the vibrating body 7 of the pump 33 is activated and water is thereby continuously conveyed from the reservoir 25 to the overflow 28, from where it reaches the steam chamber 31 via the downpipe 30. Here, the delivery rate can be adjusted by controlling the pump 33 (frequency change) of the respective heating output so that the amount of steam generated corresponds to the prevailing conditions.

FIG. 6 shows the basic structure of a hot water heater for a coffee machine 55 (only partially shown) with a storage container 34, a U-shaped flow heater 35 and a brewing head 36 with an outlet opening 37. The brewing head 36 is connected to the flow heater 35 by a riser 38 connected. The storage container 34 is connected to the flow heater 35 via a falling line 39, in which a pump 40 of the type shown in FIG. 3 is located. The components of the pump 40 have therefore been given the same reference numerals as in FIG. 3.

The described design of the hot water heater for a coffee machine 55 enables the pump 40 to convey the water to the outlet opening 37 without the support of Steam, for example already at a water temperature of approx. 90 ° C. As a result, the calcification of the continuous-flow heater 35 can be reduced and excessive extraction of the ground coffee can be avoided. Furthermore, there is the possibility of adjusting the extraction behavior to the respective brewing quantity in the sense of an optimal taste formation by regulated dosing of the heating power of the instantaneous heater 35 and the delivery quantity of the pump 40.

FIG. 7 shows a wash bottle 41 with a storage container 42, which can be filled with water through a closable fill opening 43. Under the bottom 56 of the reservoir 42 there is a pump 44, the pump chamber 9 of which is connected to the reservoir 42 through an inlet 4 with the inlet valve 5. A riser 45 leads from the pump chamber 9 through the storage container 42 to the bottle neck, which carries a spray head on which the outlet opening 46 is formed. The basic structure of the pump 44 corresponds to that of the pump 40 according to FIG. 1. Its oscillating body 7 can be connected via electrodes 8 to an electrical energy supply device arranged in the lower part of the wash bottle 41, which is not shown, in order to operate water from the reservoir 42 to the outlet opening 46 of Promote spray head. The spray bottle 41 described is suitable, for example, for moistening laundry, as a hair humidifier or as a wallpaper removal device.

In FIG. 8 the overflow 28 according to FIG. 5 is again shown enlarged, but with an additional variant, namely that a valve 57 which regulates the flow of water is formed at the transition from the overflow 28 to the downpipe 30. The valve 57 can be, for example, a slide that is adjustable in height,

as shown in Fig. 8. or be designed as a normal rotary valve, so that each time the cross-section of the downpipe 30 is changed. In Fig. 8 the valve is shown in the open position. Furthermore, an opening 58 is formed on the housing of the overflow 28 above the outlet opening 37, via which water, as soon as it has reached the lower edge of the opening 58, exits and flows back into the storage container 25 shown in FIG. 5. This ensures a constant filling level in the overflow 28 and thus a constant flow rate at the valve 57 to the downpipe 30. The valve 57 has the advantage that, depending on the use of the iron, more or less water and thus steam can be metered into the steam chamber without the piezo-electric pump having separate control electronics, which is relatively complex. must be provided.

Claims (13)

1. An electrically powered pump (40, 44) for the delivery of water in domestic appliances, including a pump chamber (9) having a diaphragm (6) and a piezoelectric oscillatory member (7) attached to the diaphragm (6), in which the pump chamber (9) is connected to a reservoir (25, 34, 42) adapted to be filled with water through an inlet (4, 17) on which a check valve (4, 18) impeding flow in the direction of the reservoir (25, 34, 42) is provided, and further to a load through an outlet (10, 21), in which the reservoir (25, 34, 42) is arranged at a higher level than the pump chamber (9), and in which the check valve (4, 18) closes the connection from the reservoir (25, 34, 42) to the pump chamber (9) in the presence of a pressure above atmospheric in the pump chamber (9), so that fluid is supplied through the outlet (10, 21) to a discharge orifice (37, 46) (delivery cycle), while on the other hand the check valve (4, 18) is opened in the presence of a pressure below atmospheric, enabling fluid to flow through the reservoir (25, 34, 42) into the pump chamber (9) (suction cycle),
   characterized in that a riser (11, 38, 45) extends from the outlet (10) of the pump chamber (9) to the discharge orifice (37, 46), that said discharge orifice is arranged above the maximum fill level of the reservoir (25, 34, 42), and that movement of the diaphragm (6) during the suction cycle produces in the area of the check valve (4, 18) independently of the fill level in the reservoir (25, 34, 42) a pressure below atmospheric relative to the water pressure prevailing on the inlet (4, 17) so rapidly that water flows from the reservoir (25, 34, 42) into the pump chamber (9).
2. The pump as claimed in claim 1,
   characterized in that a vented overflow (28) from which a downspout (30, 39) branches off adjoins the discharge orifice (37, 46).
3. The pump as claimed in claim 2,
   characterized in that a valve (57) adapted to control the passage of water is provided in the conduit (11, 30; 33, 38, 36; 45) between the outlet (10, 21) and the load.
4. The pump as claimed in claim 3,
   characterized in that the valve (57) is provided in the overflow (28) to the downspout (30, 39).
5. The pump as claimed in claim 2,
   characterized in that an opening (58) adapted to control the fill level in the overflow (28) is provided in the overflow (28), said opening being in fluid communication with the reservoir (25).
6. The pump as claimed in claim 1,
   characterized in that the diaphragm (6) is comprised of an electrically conductive material, for example, metal, and that the surface of the diaphragm (6) on the side close to the pump chamber (9) is covered with an insulating film (48) formed of a nonconductive material.
7. The pump as claimed in claim 1,
   characterized in that the inlet valve (5) is comprised of a thin-walled disk (12) formed of an elastically deformable material pivotally mounted on the wall of the pump chamber (9).
8. The pump as claimed in claim 7,
   characterized in that the disk (12) of the inlet valve (5) covers the inlet opening (4), that said disk (12) is provided with an incision (13) shaped in the manner of the arc of a circle, and that the area enclosed by the incision (13) defines a valve flap (14) adapted to be lifted clear of the inlet opening.
9. The pump as claimed in claim 1,
   characterized in that the pump chamber (9) is bounded by two opposed diaphragms (6) carrying each a piezoelectric oscillatory member (7), said oscillatory members (7) being adapted to be excited inversely.
10. The pump as claimed in claim 1,
    characterized in that also the outlet (10, 21) of the pump chamber (9) includes a check valve (20) impeding flow in the direction of the pump chamber (9), said check valve being comprised of a thin-walled conical member formed of an elastomeric material, with an incision (21) being provided at the tip of the cone extending in the direction of flow.
11. The use of the pump according to claim 2 in a steam iron,
    characterized in that the pump (33) is mounted on the bottom of the reservoir (25) and the riser (11) is connected to the overflow (28) arranged laterally adjacent to the reservoir (25), from which overflow the delivery pipe (30) extends which is connected to the steam generating chamber (31) in the soleplate structure (32) of the steam iron.
12. The use of the pump according to any one of the claims 1 to 10 in an appliance for the preparation of hot beverages,
    characterized in that the pump (40) is arranged between the outlet of the water reservoir (34) and the inlet of a flow-through heater (35).
13. The use of the pump according to claim 1 in a spray bottle,
    characterized in that the pump chamber (9) is arranged beneath the bottom of the bottle and is connected to the bottle neck carrying a spray head (46) by means of a riser (45) extending through the bottom of the bottle.

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