EP2559370B1

EP2559370B1 - Water bearing appliance with an improved water pump

Info

Publication number: EP2559370B1
Application number: EP11177791.8A
Authority: EP
Inventors: Marco Maiero; Joseph Migeot
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2011-08-17
Filing date: 2011-08-17
Publication date: 2014-03-26
Anticipated expiration: 2031-08-17
Also published as: EP2559370A1

Description

Field of technology

The present invention relates to a water bearing appliance having a water circuit provided with an improved water pump. In particular said appliance may be a water bearing machine, such as a laundry washing and/or drying machine or a dishwasher.

Background

A water bearing machine of known type, like a laundry treating machine for example, has an article treating chamber adapted to receive articles to be treated and a water circuit for supplying and/or remove water to/from said chamber. In a laundry dryer, a water circuit is provided for collecting moisture condensed from wet laundry and for conveying such condensate to a reservoir. In general, all kind of water bearing household appliances has at least one pump device installed to move water from inside to outside of the machine or vice versa, or for moving water from a part to another within the machine itself. In the latter case, the water used in a water bearing machine, like a laundry treating machine for example, is re-circulated several times in order to be reused within an article treating chamber, such as a drum rotatably mounted in a tub, where the laundry is treated for carrying out a washing process thereon. The water is drained from the tub, normally from a bottom portion thereof, through a pipe and then returned by means of a recirculation pump to the tub through an opening in an upper portion of the tub.
Usually a recirculation pump includes an impeller chamber, for instance formed in a first end of a pump support which is made in the form of an open ended tube. A motor head, received in a second end of the tube opposite to the first end, drives an impeller which is set on the motor shaft and which is received within the impeller chamber. The impeller chamber formed in the tube is closed by a discharge pipe coming from the tub of the washing machine and a sleeve protruding radially from the impeller chamber is hydraulically connected to a pipe that receives water pumped by the impeller.
In operation, the recirculation pump draws water from the discharge pipe and feeds it back into the tub, at the top thereof, via a return pipe.
A recirculation pump of such known type does not usually need, in normal operational conditions, to bear low temperatures. However it could happen that in exceptional conditions (e.g. if the household appliance is kept outdoor in winter time) or during pre-installation transport, the recirculation pump might encounter temperatures below 0°C.
As an example of circumstances where low temperatures could be an issue, it has to be considered that before the washing machine is delivered from the factory, a series of tests are performed, one of which is directed to check the presence of possible fluid leakage, especially in water conduits. To perform this test, water is introduced into the washing machine through the ordinary water inlet pipe so as to fill the tub, the water discharge circuit connected to the tub and also at least part of the water recirculation circuit. Once verified that there is no fluid leakage, water introduced for test purposes is drained from the machine through the ordinary water discharge circuit by means of a suction device. Due to the recirculation circuit conformation an amount of test water remains entrapped in the recirculation pump suction pipe and in the recirculation pump without any possibility to be drained.
This fact, in normal condition, i.e. at the factory normal temperature condition (about 20 °C) or when the temperature keeps well above 0°C, does not constitute a problem.
Conversely, during storage and/or transportation of the washing machine at lower temperature, the water remained inside the recirculation circuit could freeze and the volume increase due to the ice so formed could cause either the break of a portion of the discharge pipe coming from the tub of the washing machine and being connected to the recirculation pump or even the break of the impeller chamber. A further possible damage due to the ice formation within the water recirculation circuit may consist in the disconnection of said discharge pipe from the pump impeller chamber. In fact, when the water inside the recirculation pump freezes, the discharge pipe and the impeller chamber are pushed apart from each other thereby causing a leakage in the recirculation circuit.
Both the break and the disconnection cited above cause a water leakage the first time that a user activates the washing machine with the consequent unpleasant need for him/her to ask for a machine repair.
It has to be noted that, even if problems caused by the freezing of water remained entrapped in a washing machine have been discussed with particular reference to a water recirculation circuit, it may be appreciated that the same problems may also involve the pump device provided in the article treating chamber water drain circuit, and, in general, all pump devices installed in a water bearing appliance that may undergo a temperature below 0 °C.
Japanese Patent Application Publication JP1099592 describes a pump for a washing machine in which, to prevent the pump from being damaged due to the freezing of water, a freely compressible hollow body is incorporated into a water storage part formed in the pump case. When water in the pump case is frozen in winter, the freely compressible hollow body incorporated into the pump case absorbs the expansion in volume of ice to eliminate the imposition of pressure on the inner walls of the pump case. This prevents the breaking and cracking of the pump case due to freezing.
One of the drawbacks of the pump of the Japanese Publication JP1099592 is that an additional space, namely that for the freely compressible hollow body inside the water storage part, is to be provided in the pump case, thus increasing the overall dimension of the pump.
Moreover, measures are to be taken to avoid that the compressible hollow body moves to the impeller, thus hindering the recirculation pump operation, such as a grid or other retention means.
An improved solution which avoids the need of an extraneous body in a pump device would be highly appreciated.

Objects of the disclosure

It is an object of the present disclosure to overcome at least some of the problems associated with the prior art.
A further object of the present invention is to provide a water bearing appliance, in particular a washing machine, having a water circuit operated by a pump which can bear low temperatures without the need of containing an extraneous body.
Another object of the invention is to provide a water bearing appliance, in particular a washing machine, having a water circuit operated by a pump which can bear low temperatures without compromising the appliance functionality.
The object of the present invention is to provide a water bearing appliance, in particular a washing machine, having a water circuit operated by a pump whose case can adapt, i.e. change its shape, to compensate for the increased volume of the frozen water inside the pump.
It is a further object of the invention to provide a water bearing appliance, in particular a washing machine, having a water circuit operated by a pump, as mentioned above, in which no additional spaces are to be included in the case of the pump for such compensation, nor any additional body inside the pump, and in which, therefore, no measures are to be taken to avoid undesirable movements of such body.
A further object of the invention is to provide a water bearing appliance, in particular a washing machine, having a water circuit operated by a pump, as mentioned above, without increasing manufacturing cost and reducing productivity.

Summary

The present disclosure provides a water bearing appliance as set out in the accompanying claims.
According to one aspect of the present invention there is provided a water bearing appliance comprising an article treating chamber and a water circuit having a pump for moving water within said water circuit, the pump comprising a case having walls forming a fluid accessible cavity, the water bearing appliance being characterized in that at least a portion of said case walls form a pressure-absorbing member which is adapted to elastically deform, so that the pressure caused by solidification of water contained in the case can be absorbed.
In a preferred embodiment the case comprises a first portion having a first rigidity and a second portion having a second rigidity greater than said first rigidity, the first portion forming the pressure-absorbing member. Said pressure-absorbing member can be in the form of a cap tightly closing said cavity.
Also a pump inlet pipe is connected to the cap and in a preferred embodiment such pump inlet pipe and the cap are integrally formed as a single unitary piece.
In an embodiment of the present invention said pump inlet pipe is fluidly connected to the article treating chamber to receive water therefrom and said cavity accommodates a fluid impeller.
In a further embodiment of the invention the case has a tubular structure comprising a first end closed by a cap and a second end closed by a motor device provided for driving a fluid impeller which is positioned within said tubular structure.
Advantageously, the pressure-absorbing member is made of an elastically deformable material comprising rubber or an elastomeric material
According to a further aspect of the present invention the water bearing appliance is in the form of a laundry treating machine, or a dishwasher.
The present invention further provides a water bearing appliance wherein said water circuit drains water from a first region of the article treating chamber and reintroduces said water within the article treating chamber though a second region thereof by means of the pump.
The present invention offers a number of benefits. One of the advantages is that there is no need of an extraneous body within the pump, while making the pump suitable to bear low temperatures. This feature is particularly advantageous because no additional spaces are to be included in the case of the pump for such compensation, nor any measures are to be taken to avoid undesirable movements of such extraneous body. Also, the pump is easy to mount and easy to produce, without increasing manufacturing cost and reducing productivity.

Brief description of the drawings

Reference will now be made, by way of example, to the accompanying drawings, in which:

Figure 1 is a schematic view of a water bearing appliance, in particular a laundry washing machine, according to a preferred embodiment of the present invention;
Figure 2 shows a pump of the water bearing appliance of Figure 1, according to a preferred embodiment of the present invention;
Figure 3 is an enlarged view of detail A of Figure 2;
Figure 4 is a side view of the pump of Figure 2, according to a preferred embodiment of the present invention;
Figure 5 is a section view taken along line B-B of Figure 4.

Detailed description of preferred embodiments

The following description of the invention is referred to a water bearing appliance embodied as a laundry washing machine as mere example. However, the present invention may be embodied also in other types of water bearing appliances such as a laundry washing and/or drying machine, and a dishwasher. Referring now to Figure 1, a laundry washing machine 1 includes a cabinet 102 containing the machine operational components, i.e. components that allows the machine to work for carrying out a treatment on laundry, a main water inlet pipe 104 hydraulically connected to a main water source, such as a public water net, for supplying water to the washing machine. The main water inlet pipe 104 provides water to a treating agent dispenser 106 which is in turn hydraulically connected with a tub 101 where drum 108 is rotatably mounted. Drum 108 defines an article treating chamber 110 adapted to receive articles 112 to be treated. A water collector 114, placed on the tub 101 bottom portion, drains fluid from the tub 101 towards a water draining circuit 115 for exhausting it outside the machine. The water draining circuit 115 comprises a discharge pipe 111 wherein a pump device 116 is provided for moving water within said circuit 115.
The wash water used in washing process is drawn from the tub 101 and returned thereto by means of a recirculation circuit 103. The recirculation circuit 103 is composed of an outlet pipe 105 coming from the tub 101, a recirculation pump 107 and a return pipe 109.
In particular the outlet pipe 105 is, for instance, a branch from the discharge pipe 111 for drainage of the water from inside the tub 101 and also forms the recirculation pump inlet pipe.
A return pipe 109 originates from the recirculation pump 107 and is connected to an upper portion of the tub 101.
In operation, the recirculation pump 107 draws water from the tub bottom portion via the water collector 114 and feeds said water back to the tub 101, at the top thereof via the return pipe 109.
With reference to Figure 2, a recirculation pump 107 according to a preferred embodiment of the present invention is shown. An impeller chamber 218, adapted to house an impeller, is formed in the pump support 201, which is preferably made in the form of an open ended tube 203 provided with a mounting flange 205 having holes 207 for fixing the pump to a portion of the machine cabinet 102 through screws (not shown).
One open end 220 of the tube 203 is closed by the head 219 of a motor 209 fastened to the tube 203 by means of fastening screws 211.
It will be apparent to those skilled in the art that different driving means other than the motor 209 can be used for driving the recirculation pump, although a motor is most commonly used.
As better shown in the enlarged view of Figure 3, the other open end 230 of the tube 203, opposite to the open end 220, is closed by a cap 301, fastened to the tube 203 by means of a retention ring 303. The walls of the case formed by cap 301 and tube 203 form a fluid accessible cavity 309.
Those skilled in the art will understand that different means other than the retention ring can be used to fasten the cap 301 to the tube 203, without departing from the scope of the invention.
A pump inlet pipe 305 is connected to the cap 301 for supplying water to the impeller chamber 208 . Said pump inlet pipe 305 may extend in length so as to form the outlet pipe 105 which is hydraulically connected to the tub 101 and, in turn, to the article treating chamber 110 of the washing machine (see Figure 1). In a further preferred embodiment, the pump inlet pipe 305 and the cap 301 may be integrally formed as a single unitary piece. An outlet opening 307, communicating with the impeller chamber 208, is also provided on the pump support 201 for allowing pumped water to leave the impeller chamber 208.
As shown in Figures 4 and 5, the water recirculation pump 107 has an impeller 501 which is housed within the impeller chamber 208 and it is keyed onto the motor shaft 215, so that it remains within the tube 203. The water is pumped by the impeller 501 through the outlet opening 307 and through the recirculation circuit 103 to be fed back to the article treating chamber 110 of the water bearing appliance 1. It will be apparent to those skilled in the art that a different pumping device other than the motor can be used, for instance a gear or a pair of gear in the case of a gear pump, or a diaphragm connected to a reciprocating driving device in the case of a diaphragm pump.
When mounted together, the tube 203, the motor head 219 and the cap 301 form the case of the recirculation pump. According to the present invention a portion of the case is made of an elastically deformable material so as to form a pressure absorbing member. In other words, said case may comprise a first portion having a first rigidity and a second portion having a second rigidity greater than the first rigidity, the first portion forming the pressure absorbing member. Said rigidity of the case portions being conferred by the material used to form them and by their shape. In the embodiment shown in the Figures 2-5 the cap 301 forms the pressure absorbing member made of an elastically deformable material (e.g. rubber). Alternative embodiments are possible, e.g. the tube 203 could be totally or partially made of elastically deformable material. As an example a bottom part of the tube 203 could be provided with a cap of an elastically deformable material having the same function described for the cap 301. Another possible alternative is that several small portions of the tube 203 or the cap 301 are made of an elastically deformable material, e.g. the cap 301 could be made of a rigid material with some opening (e.g. in the forms of circles) which are sealed with an elastically deformable material (e.g. rubber) acting as pressure absorbing members.
The elastically deformable material can be rubber or an elastomeric material or any other suitable material, which can be preferably shaped in the form of a cap or other similar component, is waterproof and resistant to low temperature. The selected material must be able to deform elastically so as to expand or contracting for absorbing the deformation caused to the walls of the cavity 309 by the pressure generated by the increase of volume due to the freezing of water included in the cavity 309. The same material allows the pressure absorbing member to return in its original shaped when ice melts.
The present invention provides a water bearing appliance, e.g. a washing machine, having a recirculation pump whose case can adapt its shape and/or its inner size to compensate for the increased volume of the frozen water inside the recirculation pump. The pressure absorbing member, e.g. the cap 301 or the bottom part of the tube 203, permits, at lower temperature, the expansion of the impeller chamber 208 and do not cause any damages at the recirculation pump assembly. In case of ice formation within the recirculation pump 107, the provision of a pressure absorbing member allows also the connection between the pump inlet pipe 305 and tube 203 made by a retention ring 303 to remain stable and tight.
According to the invention no additional spaces are to be included in the case for such compensation, nor any additional body inside the recirculation pump and therefore no measures are to be taken to avoid undesirable movements of such body.
The recirculation pump is improved by a simple solution, easy to implement, without increasing manufacturing cost and reducing productivity.
In general, the resistance of the circuit at very low temperature is improved without damages caused by ice and its expansion.
It will be understood that, while in the foregoing description reference was mainly made to a water bearing appliance embodied in the form of a laundry washing machine, the disclosure of the present invention is suitable for applying the invention to other water bearing appliances, such as tumble dryer machine, a dishwashing machine, and in general for any apparatus having a water circuit provided with a pump. In the embodiment of the invention disclosed in Figures 1-5 not only the water recirculation circuit 103 may be provided with a pressure absorbing member suitable for absorbing the pressure caused by freezing of water contained therein, but also the water draining circuit 115 may similarly provided with such a pressure absorbing member.
The invention is by no means limited to the above-described embodiment given as an example and represented in the accompanying drawings.
A pump of the water bearing appliance of the present invention can be easily produced, using techniques which will be apparent to those skilled in the art, thus not affecting the manufacturing cost and the productivity.
It will be appreciated that alterations and modifications may be made to the above without departing from the scope of the disclosure. Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply to the solution described above many modifications and alterations. Particularly, although the present disclosure has been described with a certain degree of particularity with reference to preferred embodiment(s) thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible; moreover, it is expressly intended that specific elements described in connection with any disclosed embodiment of the disclosure may be incorporated in any other embodiment as a general matter of design choice.
For example, similar considerations apply if the components (e.g. the cap or the motor) have different structure or include equivalent units. Also, it should be easily understood by those skilled in the art that the present invention may be extended to a large variety of water bearing appliances not only to a laundry washing machine that has been used in the above description as mere example of how the present invention may be embodied.

Claims

A water bearing appliance comprising an article treating chamber (110) and a water circuit (103, 115) having a pump (107, 116) for moving water within said water circuit (103, 115), the pump (107, 116) comprising a case (203, 301) having walls forming a fluid accessible cavity (309), the water bearing appliance being characterized in that at least a portion of said case walls forms a pressure-absorbing member (301) which is adapted to elastically deform, so that the pressure caused by freezing of water contained in the case (203, 301) can be absorbed.
A water bearing appliance according to claim 1 wherein said case (203, 301) comprises a first portion (301) having a first rigidity and a second portion (203) having a second rigidity greater than said first rigidity, the first portion forming the pressure-absorbing member.
A water bearing appliance according to claim 1 or 2 wherein said pressure-absorbing member is a cap (301) tightly closing said cavity (309).
A water bearing appliance according to claim 3 wherein a pump inlet pipe (305) is connected to said cap (301).
A water bearing appliance according to claim 3 or 4 wherein a pump inlet pipe (305) and the cap (301) are integrally formed as a single unitary piece.
A water bearing appliance according claim 4 or 5 wherein said pump inlet pipe is fluidly connected to the article treating chamber (110) to receive water therefrom.
A water bearing appliance according to any preceding claim wherein said cavity (309) accommodates a fluid impeller (501).
A water bearing appliance according to any preceding claim wherein said case (203, 301) has a tubular structure (203) comprising a first end (230) closed by a cap (301) and a second end (220) closed by a motor device (209) provided for driving a fluid impeller (501) which is positioned within said tubular structure (203).
A water bearing appliance according to any preceding claim wherein said pressure-absorbing member (301) is made of an elastically deformable material comprising rubber or an elastomeric material.
A water bearing appliance according to any preceding claim characterized by being a laundry treating machine or a dishwashing machine.
A water bearing appliance according to any preceding claim wherein said water circuit (103) drains water from a first region of the article treating chamber (110) and reintroduces said water within the article treating chamber (110) though a second region thereof by means of the pump (107).