WO2014053181A1

WO2014053181A1 - A cleaning sheet for cleaning the interior of a coffee machine

Info

Publication number: WO2014053181A1
Application number: PCT/EP2012/069607
Authority: WO
Inventors: Helmut PINK
Original assignee: Ecolab Inc.
Priority date: 2012-10-04
Filing date: 2012-10-04
Publication date: 2014-04-10

Abstract

The present invention relates to a cleaning sheet (28) for sealing a flowing path of a sieve holder (10) for cleaning the interior of a coffee machine, comprising an elastically deformable base body (30) having a size being adapted to allow the flowing path of the sieve holder (10) to be sealed, wherein a cleaning agent (32) is fixed to the base body (30). Such a cleaning sheet (28) may significantly improve the effectiveness and simplicity of a cleaning procedure of the interior of a coffee machine, such as a boiling unit and the conduits being directed thereto and there from. Additionally, a cleaning procedure may be performed by users significantly more reliable and secure. The present invention further relates to a method of cleaning the interior of a coffee machine and to a use of a cleaning sheet (28) for cleaning the interior of a coffee machine.

Description

A cleaning sheet for cleaning the interior of a coffee machine

Technical field of the invention This invention relates to a cleaning sheet for sealing a flowing path of a sieve holder for cleaning the interior of a coffee machine, wherein the coffee machine comprises a boiling unit and a sieve holder connected thereto.

Background of the invention

Coffee machines having a boiling unit and a sieve holder generally work by conveying hot water of exemplarily 90 °C with elevated pressures such as 3-4bars through the sieve holder, the latter being filled with pre-densified coffee ground. This measure allows removing coffee oils from the coffee ground resulting in e.g. espresso having the desired crema. Before cleaning the sieve holder by removing the coffee ground there from the overpressure may be relieved by switching a respective valve such as a three way valve. This leads to water being enriched with respect to coffee oils flowing back through the boiling unit in a discharge conduit and further to an outflow. As a result, the boiling unit has to be cleaned after a certain amount of time, or usage, respectively. Such a cleaning procedure of the boiling unit, or boiling head, respectively, according to the prior art, is affected by exchanging the sieve for accommodating the coffee ground by a closed blind insert. The sieve holder is then fixed to the sieve holder support and hot water is forced into the sieve holder. After switching a respective valve such as the three way valve, the hot water flows through the boiling unit and cleans the latter as well as the respective conduits. This cleaning procedure may be repeated several times until clean water is collectable at the outflow of the coffee machine.

The afore-mentioned cleaning procedure, however, is complex and the efficiency may be further improved.

SUMMERY OF THE INVENTION

It is therefore an object of the present invention to provide a measure for simplifying the cleaning procedure of the interior of a coffee machine and allowing this cleaning procedure to be more efficient.

This object is solved by a cleaning sheet for sealing a flowing path of a sieve holder for cleaning the interior of a coffee machine according to claim 1 of the present invention .

Accordingly, a cleaning sheet for sealing a flowing path of a sieve holder for cleaning the interior of a coffee machine comprises an elastically deformable base body having a size being adapted to allow the flowing path of the sieve holder to be sealed, wherein a cleaning agent is fixed to the base body.

A cleaning sheet like defined above is especially usable for cleaning the interior of a coffee machine, which preferably comprises a cleaning procedure of a boiling unit or boiling head, respectively and conduits guiding thereto and/or there from. Such a cleaning sheet provides an improved efficiency of such a cleaning step and is furthermore very easy to use.

A cleaning sheet according to the present invention may thereby particularly be formed as a means which has a very small thickness compared to its size such as diameter. For example, the sheet may have a foil-like structure and/or it may be formed disc-like.

In detail, due to the fact that a cleaning agent is fixed to the base body, no cleaning agent has to be stored in the vicinity of the coffee machine. This results in less storage room to be required which may be especially advantageous in case of small kitchens or the like. Additionally, it may be prevented that in case a cleaning step is desired, the cleaning agent being stored is empty or must be searched because it was not accurately stored.

Additionally, it is ensured that an appropriate cleaning agent is used at every cleaning procedure. In detail, it is prevented to use a cleaning agent which is, for example, not especially adapted for cleaning the interior of a coffee machine which in that case may cause a health problem for the consumers. As a result, the cleaning procedure may be performed very secure and reliable. Suitable cleaning agents may comprise commercial available dish washer detergents and the like and cleaning agents, which are commonly used for cleaning purposes of the interior of coffee machines.

Next to ensure using the appropriate type of cleaning agent, it may be assured to use an appropriate amount of cleaning agent. According to this, the usage of an immoderate amount of cleaning agent may be permitted allowing saving cleaning agent. This is advantageous for the environment and further allows reducing the costs for cleaning and thus for operating a coffee machine. Apart from that, it may be assured that a cleaning procedure will be performed in a defined way and in the shortest possible time.

It may thereby be provided that the amount and/or type of cleaning agent to be provided and fixed to the base body, or cleaning sheet, respectively, may be adapted for a special use. For example, in case a cleaning sheet is adapted for daily use, it may be respectively labelled and it may comprise an amount and type of cleaning agent which is appropriate for this application. Further, in case a cleaning sheet is provided for weekly use or for monthly use, for example, it again may be respectively labelled and it may comprise an amount and type of cleaning agent which is appropriate for this application. As a result, the cleaning step may furthermore be simplified and made more secure and reliable. Further, the cleaning agent is appropriately arranged and fixed such, that it is located inside the flowing path during use, i.e. when it is fixed to seal the top opening of the sieve holder, and further on the side of the base body being located opposite to the sieve and thus directed to the boiling unit when being in use.

Apart from that, due to the fact that the base body has a size being adapted to allow the flowing path, or the top opening, respectively, of the sieve holder to be sealed, the handability is improved. In fact, the cleaning sheet solely has to be fixed on top of the sieve holder and a cleaning procedure may start. The feature that the size is adapted to allow the flowing path of the sieve holder to be sealed shall particularly mean that no passage for water or a gas is allowed during use. This may be realized, for example, if the base body is larger than the top opening of the sieve holder. For example, a border, or an edge, respectively, may be provided which is arranged outside the sieve holder when being in use. Such a border may have a width of equal or more than 0,5cm to equal or less than 2cm in order to allow a good handability. Consequently, the size as well as the geometry of the cleaning sheet, or the base body, respectively, may be adapted to the top of the sieve holder .

Due to its elastic deformability and thus its flexibility, the cleaning sheet may easily be fixed on top of the sieve holder, or between the sieve holder and the sieve holder support, respectively by positioning it on top of the sieve holder and then fixing the sieve holder to its support. Consequently, the sieve holder, or its flowing path through which when brewing coffee hot water is guided, may easily be sealed without removing the sieve by exchanging it by a blind insert. A usage of the cleaning sheet may thus be realized in a very fast and easy manner allowing cleaning the coffee machine very quickly. Apart from that, the step of exchanging the sieve by a blind insert according to prior art often is complicated due to the tight and strong fitting of the sieve in the sieve holder, e.g. by respective clamps, requiring a great exertion of force for the user performing the cleaning step according to prior art. Accordingly, by omitting this step according to the invention, the cleaning step is significantly simplified and may furthermore be realized by users not being able to exerting such forces.

Furthermore, no additional part such as the blind insert has to be stored in direct vicinity to the coffee machine. Thus, no additional part for cleaning the coffee machine may get lost according to which a cleaning step may be realized more reliable.

As a result of the above, it is allowed to clean the interior of a coffee machine very fast and easy because of which the cleaning step will be performed much more reliable by the user of the coffee machine.

Further, due to its elastic deformability, the cleaning sheet may allow a more effective cleaning procedure particularly of a boiling unit, or boiling head, respectively, of the coffee machine. In fact, when being inserted and fixed on top of the sieve holder, or between the sieve holder and the sieve holder support, respectively, the cleaning sheet may seal the flowing path of the sieve holder directly at the water inlet from the boiling unit essentially without a clearance volume, or, compared to a blind insert known from the prior art, with a clearance volume having a significantly reduced size. The amount of water resting in that clearance volume and not being conveyed to the boiling unit is thus likewise reduced compared to prior art. Accordingly, a cleaning sheet according to the invention may prevent many cleaning steps to be required for removing all of the dirty water out of the clearance volume and for dissolving and thus using the entire cleaning agent being present. Accordingly, the effectiveness of a cleaning procedure may be enhanced. In fact, the interior of a coffee machine may be cleaned with a significantly reduced amount of cleaning steps. Apart from that, due to the elastic deformability of the cleaning sheet, an amount of water may be conveyed into the sieve holder which not only corresponds to the clearance volume, but which is furthermore significantly enlarged by elastically deforming the cleaning sheet to the inside of the sieve holder and thus my forming an additional accommodation room. As a result and compared to blind inserts according to the prior art, the amount of water dissolving the cleaning agent and flowing through the boiling unit at one cleaning step may significantly be increased because of which every cleaning cycle may be realized more effective. Furthermore, when providing an increased volume of water, a greater amount of cleaning agent may be dissolved according to which less cycles are required for dissolving and using the entire provided cleaning agent, further accelerating a cleaning procedure. It is thus obvious that the property of having a significantly reduced clearance volume may be combined with an increased amount of water being provided for cleaning the interior of the coffee machine, which is mainly due to the elastic deformability of the cleaning sheet.

Furthermore, and due to the elastic deformability of the cleaning sheet, the mechanism of conveying the water to the boiling unit is not only performed by e.g. depressurizing the respective volume by switching a respective valve, but it may be assisted by the restoring force of the cleaning sheet when it returns into it standard position after a elastic deformation. This allows all or nearly all of the water and further a larger amount thereof being accommodated by the cleaning sheet to be conveyed to the boiling unit when the cleaning sheet restores to its original shape. As a result and due to the fact that the cleaning sheet in principle acts as a membrane pump, the effectiveness of the cleaning procedure is further improved.

It may thereby be provided that the whole cleaning sheet is elastically deformable, for example in the same amount, or that the cleaning sheet is only partly elastically deformable. Such a locally restricted elastic deformability may especially be realized in a portion being required with respect to the cleaning procedure like described above. For example, the portion where the cleaning sheet is fixed may just be flexible but need not to be elastically deformable.

Furthermore, by using cleaning sheets for cleaning purposes, the cleaning behaviour of users is easily controllable just by counting the used cleaning sheets, or cleaning pads, respectively. As a result, users, such as users working in a coffee bar, restaurant, or the like, will clean the coffee machine more reliable.

As a result, by providing a cleaning sheet for sealing a flowing path of a sieve holder for cleaning the interior of a coffee machine which is formed like described above, the effectiveness and simplicity of a cleaning procedure may significantly be improved, thereby making a cleaning procedure performed by users more reliable and secure.

According to an embodiment, the cleaning agent is fixed to the base body by adhesive forces. For example, the cleaning agent may be applied to the base body in the form of a paste-like substance. When drying the cleaning agent, the latter will then be fixed to the base body. As an alternative, a glue or an adhesive, respectively may be used. As an example, an aqueous sugar-solution may be used as adhesive. Such an adhesive is well usable even for food related applications and further securely fixes the cleaning agent to the base body. By fixing the cleaning agent by one of the afore-mentioned measures, it may be secured that the cleaning agent is not removed from the cleaning sheet during a transport, a storage, etc. and thus before use. It is thus secured that the cleaning agent is still provided at the cleaning sheet when it is positioned in place. Apart from that, the cleaning agent may easily be removed, or dissolved, respectively, from the cleaning sheet when it is desired and thus when it comes in contact with water. According to this, this embodiment makes the cleaning procedure even more secure and reliable. It is apparent from the above that the cleaning agent may be fixed to the base body directly without any layers there between, or it may be fixed to the base body indirectly and thus, for example, with one or more layers between the base body and the cleaning agent.

According to an embodiment, the cleaning sheet has a modulus of elasticity in an amount of ≥ 1 MPa to ≤ 20 MPa at an elongation of 100%, which may be determined by DIN EN ISO 527. Such a modulus of elasticity (Young's modulus) efficiently enhances the cleaning properties when cleaning the interior of a coffee machine. In fact, by using such elastic properties, the cleaning sheet still has a sufficient stiffness for insuring that the cleaning sheet is not deformed to fully infill the sieve holder. Further, it is sufficiently deformable to allow an appropriate amount of water to be accommodated in an accommodation room being generated when the cleaning sheet is elastically deformed. Apart from that, the above identified elasticity allows the cleaning sheet having a restoring force which effectively assists the conveying mechanism of the water. Generally, the modulus of elasticity may thereby be caused by the base body as such or by a further element, like will be apparent down below . According to an embodiment, the base body has a thickness in the range of ≥ 0,2 mm to ≤ 1 mm. According to this embodiment, the stability of a cleaning sheet may be especially improved. In detail, due to the fact that water is conveyed to the cleaning sheet by using high pressures, such as 3 to 4 bars, and elevated temperatures, such as 90°C, it should be avoided that the water damages the cleaning sheet and passes through the latter. Accordingly, a cleaning step may be formed very reliable and thus additional cleaning steps which have to be performed in case a cleaning sheet is damaged may be omitted. Further, such a thickness may easily allow fixing the cleaning sheet on top of the sieve holder and fixing the latter in its sieve holder support. Therefore, a cleaning sheet is especially easy to handle according to this embodiment.

According to an embodiment, the base body is formed from plastic, in particular as a plastic disc. In detail, especially by forming the cleaning sheet, or its base body, respectively, from a plastic, a broad variety of cost-saving materials may be provided, which particularly may have advantageous properties such as modulus of elasticity, for example. Apart from that, a plastic material withstands high temperatures and pressures further enhancing the stability due to the fact that mostly water is conveyed to the cleaning sheets with elevated temperatures and pressures. Additionally, a suitable stability should be provided in order to allow fixing the cleaning sheet by positioning it on top of the sieve holder and fixing the latter in its support- Further, especially, when the plastic base body is formed in the form of a disc, it is especially easy to handle and to put it into the right position, making a cleaning process even more reliable. Suitable plastic materials may thereby be chosen in a non-limiting manner from the group consisting of elastomers, such as ethylene propylene diene monomer (EPDM) , polyesters, polyethyleneterephtalate (PET) , polyvinylchloride (PVC) , polyethylene (PE) , polypropylene (PP) . According to an embodiment, the cleaning sheet comprises at least one fixing element for fixing the cleaning sheet in position during use. According to this embodiment, the cleaning process may be realized even more reliable and secure. In detail, due to the fact that water is conveyed to the cleaning sheet with elevated pressure, this may under circumstances, such as when a handling error occurs, cause the danger that the cleaning sheet is not accurately hold in place but may slip into the interior of the sieve holder. According to this, the flowing path of the sieve holder may be sealed inaccurately allowing water to flow there through. Consequently, no appropriate cleaning effect may be provided due to the fact that no or only a limited amount of water is conveyed to the boiling unit. Further, the surrounding of the coffee machine may get dirty, which should be avoided. According to this embodiment, however, such negative effects may especially effectively be avoided due to the fact that the cleaning sheet is securely hold in place and an accurate sealing of the flowing path of the sieve holder is in any case realized. As a result, the reliability of a cleaning process is even more improved according to this embodiment. The fixing element or the plurality of fixing elements may be provided on the side of the base body being directed to the sieve in case the cleaning sheet is working, or it may be located on the opposite side, or it may be located on both sides.

According to an embodiment, the fixing element is formed as thickening, particularly as a thickening particularly surrounding the sieve holder when a cleaning procedure is performed, such as a ring-like thickening. By forming the fixing element as a ring-like thickening, or projection, respectively, a shifting of the cleaning sheet, for example by a displacement into the sieve holder, can especially securely be avoided in any direction. Apart from that, next to its object of holding the cleaning sheet in place, the ring-like thickening may act as a positioning aid to help the cleaning sheet to be positioned in an accurate manner especially in case the cleaning sheet is formed disc-shaped. Consequently, next to a very secure cleaning performance, handling errors may further be minimized. The thickening, or projection, respectively may thereby exemplarily be formed from the material of the base body, or it may be formed of a further material and attached to the base body in a secure way. The thickening, or projection, respectively, may further be formed on one or on both sides of the base body. It, or its geometry, thickness, etc. may furthermore be adapted to the structure of the connection of the sieve holder and the sieve holder support in order to provide an especially secure positioning.

According to an embodiment, the base body is formed from an elastic material. According to this embodiment, the base body as such may provide the respective elasticity and thus the adequate restoring force after being deformed. According to this embodiment, the cleaning sheet may be formed very cost-saving and easily. Apart from that, the cleaning sheet may be formed very compact and in very small dimensions resulting in very few storage room to be required. Additionally, the cleaning sheet may be especially easy to handle according to this embodiment .

According to an embodiment, the base body is provided with a restoring element. In detail, it may be preferred that a restoring element is provided on the side directed to the sieve and thus on the side being opposite to the side the cleaning sheet comes in contact with water during use. When providing a restoring element, an elastic deformation of the cleaning sheet may be caused partially or fully by said restoring element. In case the restoring element causes the full elasticity, the base body may be formed of any material being flexible enough and providing a sufficient stability. In case the restoring element supports the elasticity or the elastic restoring force together with an elastic base body as such, the restoring forces may be provided in an especially strong manner allowing especially large restoring forces. Apart from that, the restoring force may be adapted in a very accurate manner allowing to exactly influencing the water conveying behaviour. The restoring element may be connected to the base body or it may be formed as one piece with the base body. According to an embodiment, the restoring element is formed as a flexible air container, or as a foamed material. The above named restoring elements are especially cost-saving and easy to prepare making them as well usable for one way articles. These restoring elements may furthermore easily be adapted to the required restoring force leading to an especially secure, defined and reliable cleaning behaviour. A flexible air container may thereby provide its restoring force due to a compression and an expansion of the gas present in the container, whereas the foam material may cause the restoring force due to the elasticity of the material as such . According to an embodiment, the base body comprises a cleaning indicator. Such a cleaning indicator may be designed such, that the indicator displays if a cleaning step was successful in a desired manner. For example, the cleaning indicator may be positioned underneath the cleaning agent and may be formed, for example, from a non-water soluble material. In this case, the indicator may be visible only in case all of the cleaning agent was removed and was thus used for cleaning purposes. Additionally or alternatively, a respective cleaning indicator may be formed as a water soluble, non-toxic material which may be provided on the surface of the cleaning sheet. In this case, the indicator will be removed from the cleaning sheet in case a suitable amount of water was used. Such a cleaning indicator may thus assure that the cleaning procedure was successful so that the coffee machine is secured to be clean. According to an embodiment, the cleaning sheet comprises a roughened area being positioned to come in contact with at least one of a sealing of the sieve holder and a sealing of the sieve holder support. According to this embodiment, the exact position of the roughened area may be adapted to the geometry and size of the sieve holder and/or the sieve holder support and especially of a respective sealing. According to this embodiment, a cleaning step of the respective sealing may be reached due to the fact that the roughened area may physically clean the respective sealing. It may be preferred that the position of the roughened area, which may in an extreme case take the whole surface of the cleaning sheet, is adapted to the position of a fixing element. This may secure that the roughened area, especially in case it is a locally restricted area, may securely be positioned adjacent to one or more respective sealings, such as an O-ring-sealing . The roughened area may be formed, for example, by roughening the cleaning sheet at this position or area, for example by sandblasting or by providing particularly a closed porosity in order to secure a sealing at this position. Alternatively, the roughened area may be formed by providing a textile element, such as a flocking, a fabric or the like. The textile element may thereby be formed from plastics, non-woven materials or cotton, for example . According to an embodiment, a net structure is provided on the base body. The net structure is particularly fixed to the base body on the side being directed to the boiling unit when in use. It further fully or partly covers the cleaning agent. Such a particularly non water soluble net structure allows water to come in contact to the cleaning agent, but due to its function as a kind of filter, it may prevent large particles of cleaning agent or coffee to be conveyed into the boiling unit. As a result, such a structure may secure an especially effective cleaning procedure. With respect to further technical features and advantages of the cleaning sheet it is referred to the description of the method of cleaning the interior of a coffee machine, the use, the figures and the description of the figures .

A further aspect of the present invention is a method of cleaning a boiling unit of a coffee machine, the coffee machine comprising a sieve holder connected to the boiling unit, comprising the steps of: providing a cleaning sheet like described above, sealing the flow passage of the sieve holder by positioning the cleaning sheet at the top of the sieve holder and fixing the sieve holder to a sieve holder support, and guiding water to the cleaning sheet and further to the boiling unit.

A method like described above may significantly improve the effectiveness and simplicity of a cleaning procedure of the interior of a coffee machine, such as a boiling unit and the conduits being directed thereto and there from. Additionally, a cleaning procedure may be performed by users significantly more reliable and secure. According to a first step of the method, a cleaning sheet like described above is provided. Such a cleaning sheet may comprise one or more of the features like discussed in detail with respect to the cleaning sheet because of which it is referred to this respective description.

According to a second step, the flow passage of the sieve holder is sealed by positioning the cleaning sheet at the top of the sieve holder and fixing the sieve holder to a sieve holder support. Accordingly, the cleaning sheet is positioned on top of the sieve holder, or on its top opening, respectively, after which the sieve holder is fixed to its support, e.g. to the boiling unit. Consequently, at the top of the sieve holder may comprise the situation in which the cleaning sheet is partly positioned inside the sieve holder, particularly during the cleaning step.

According to a further step, water is guided to the cleaning sheet and further to the boiling unit. According to this step, the coffee machine works in a comparable manner as in case coffee is made. Accordingly, when performing a cleaning step, hot water is guided to the top of the cleaning sheet in answer to which a valve, such as a three way valve is switched in order to let the inserted water flow into the boiling head, or boiling unit, respectively. As a result, especially hot water is guided from the boiling unit to the cleaning sheet, particularly under elevated pressures. When the water is collected at the accommodation room being formed by an elastic deformation of the cleaning sheet, a valve, such as a three way valve, may be switched in answer to which water being enriched with cleaning agent is conveyed to the boiling unit, thereby cleaning the latter, and may be disposed through an outlet of the coffee machine. Such a step like described above may be repeated several times until clean water may be collected at an outlet of the coffee machine.

With respect to further technical features and advantages of the method of cleaning the interior of a coffee machine it is referred to the description of the cleaning sheet, the use, the figures and the description of the figures .

A further aspect of the present invention is a use of a cleaning sheet like described above for cleaning the interior of a coffee machine, particularly a coffee machine comprising a sieve holder for accommodating a coffee filled sieve, the sieve holder being fixed to a sieve holder support. The support may be part of or connected to a boiling unit.

The use of a cleaning sheet like described above may significantly improve the effectiveness and simplicity of a cleaning procedure of the interior of a coffee machine, such as a boiling unit and the conduits being directed thereto and there from. Additionally, a cleaning procedure may be performed by users significantly more reliable and secure. With respect to further technical features and advantages of the use it is referred to the description of the cleaning sheet, the method of cleaning the interior of a coffee machine, the figures and the description of the figures .

The afore mentioned components, as well as the claimed components and the components to be used in accordance with the invention in the described embodiments, are not subject to any special exceptions with respect to their size, shape, material selection and technical concept such that the selection criteria known in the pursuant field can be applied without a limitation.

BRIEF DESCRIPTION OF THE DRAWINGS Additional details, features, characteristics and advantages of the object of the invention are disclosed in the subclaims, the figures and the following description of the respective figures and examples, which - in exemplary fashion - show several embodiments and examples of a cleaning sheet according to the invention.

In the drawings:

Fig. 1 is an illustration of a sieve holder with a sieve positioned therein;

Fig. 2 is an illustration of a sieve holder support being arranged at the bottom of a boiling unit; Fig, 3 is an illustration of a sectional view of an embodiment of a cleaning sheet according to the invention ; . 4a-c show a further embodiment of the cleaning sheet according to the invention; Fig. 5 is an illustration of a detail of the embodiment according to figure 4 ;

Fig. 6 is a top view of a part of a sieve holder provided with a cleaning sheet according to the invention ;

Fig. 7 is an illustration of a sieve holder provided with a cleaning sheet fixed to a sieve holder support .

The illustration in Fig. 1 shows a sieve holder 10 which is part of a coffee machine. The sieve holder 10 comprises a grip 12 which is securely connected to a receptacle 14 for accommodating a sieve 16. The grip 12 may be formed of wood, for example, whereas the receptacle 14 may be formed from a metal for withstanding high temperatures. The receptacle 14 may be formed as cylindrical pot being opened at the top and having a small outlet at the bottom side. Additionally, the sieve holder 10 may comprise one or more flanges 18 for fixing it at the coffee machine like described in detail down below. When being in use, the sieve 16 may be filled with coffee ground and in case water is conveyed to the coffee ground through the top opening, coffee can be brewed by interaction with the hot water and may be filled into a cup through the outlet at the bottom side. The sieve holder 10, or its interior, respectively, may thus be understood as a brewing unit for brewing coffee.

In order to use the sieve holder 10, it may be fixed to a sieve holder support 20 like shown in figure 2. In detail, according to figure 2, the bottom of a boiling unit 22 is shown. Figure 2 thereby shows the bottom part of a boiling head 26 by which hot water is provided under elevated pressure. Accordingly, hot water may be conveyed from the boiling head 26 into the sieve holder 10 in order to brew coffee. According to figure 2, the sieve holder support 20 is formed at the bottom of the boiling unit 22. Therefore, a support having openings 24 being adapted to the flanges 18 of the sieve holder 10 are provided. As a result, the sieve holder 10 may be fixed to the sieve holder support 20 by means of a bayonet coupling .

In order to clean the interior of the coffee machine provided with said boiling unit 22 and said sieve holder 10, a cleaning sheet 28 is provided like shown in figure 3.

Such a cleaning sheet 28 is designed for sealing a flowing path of the sieve holder 10 for cleaning the interior of a coffee machine, particularly a boiling unit 22. The cleaning sheet 28 comprises an elastically deformable base body 30. The cleaning sheet 28 preferably has a modulus of elasticity in a range of ≥ 1 MPa to ≤ 20 MPa. The elasticity of the cleaning sheet 28 may be caused by the base body 30 as such, especially in case it is formed from an elastic material. Alternatively or additionally, a restoring element 32, which may be connected to the base body 30 or which may be formed in one piece with the base body 30 may be provided, may cause at least a part of the restoring force. The restoring element 32 may be formed as a flexible air container, or a foamed material, like shown in figure 3.

Additionally or alternatively, the cleaning sheet 28, or its base body 30, respectively, may have a shore hardness of ≥ 40 to ≤ 10, preferably in a range of ≥ 75 to ≤ 80.

Additionally, the base body 30 has a size being adapted to allow the flowing path of the sieve holder to be sealed. Further, the base body preferably has a thickness in the range of ≥ 0,2 mm to ≤ 1 mm. The base body 30 may be formed as a flat and flexible structure. It may be formed foil-like and for example may be formed disc-like.

With respect to its material, the cleaning sheet 28, or the base body 30, respectively may be formed from plastic. As exemplary embodiments, the plastic may be chosen from the group consisting of elastomers, such as ethylene propylene diene monomer (EPDM) , polyesters, polyethyleneterephtalate (PET) , polyvinylchloride (PVC) , polyethylene (PE) , polypropylene (PP) .

Furthermore, the cleaning sheet 28 may comprise a fixing element 34 for fixing the cleaning sheet 28 in position during use. Such a fixing element 34 may in an exemplary embodiment be formed as a ring-like thickening. The thickening may be formed from the same material as the base body 30, or it may be formed from another material. As a further example, the thickening, or projection, respectively, may be formed by a ring like element, such as a wire, which is embedded in, or encased by, respectively, the base body material.

In order to assure an effective and secure cleaning behaviour, a cleaning agent 36 is fixed to the base body 30. This can additionally be seen in figure 3, where it is schematically shown that the cleaning agent 36 is positioned on top of the cleaning sheet 28, or its base body 30, respectively. According to figure 3, the cleaning agent 36 may be provided on the base body, for example, as a pressurized pill. Additionally, it may be formed as a powder being fixed to the base body. In general, the cleaning agent 36 may fixed to the base body 30 by adhesive forces.

As further optional features, the cleaning sheet 28 may additionally comprise a cleaning indicator 38 for securing that the cleaning procedure was successful. Such a cleaning indicator 38 may be formed from a non water soluble material which may be located underneath the cleaning agent 36, or it may be formed as a water-soluble material which may be located next to the cleaning agent 36.

Alternatively or additionally, the cleaning sheet 28 may comprise a roughened area 40 being positioned to come in contact with at least one of a sealing of the sieve holder 10 and a sealing of the sieve holder support 20. This allows not only cleaning the boiling unit 22, for example, but it may additionally allow cleaning sealings leading to an improved long-term behaviour of the coffee machine to be used.

Figures 4a to 4c show a further embodiment of the present invention. According to figure 4, a net structure 33 is provided on the base body 30. Such a net structure 33 may be adapted to the base body 30 with respect to its size and geometry and may be fixed to the base body 30, for example by an adhesive, at its circumference. In detail, a circumferential adhesion may be provided at an outer region 31, for example in a dimension of 5mm. This is shown in figure 4a in a storing state and thus before use . Figure 4b shows a situation during use. In detail, it is shown that water flows in an accommodation room formed by an elastic deformation of the base body 30. It may be seen that the net structure comprises an inner hole 37 which is closable by a suitable one-way valve 35. Of course, water may flow in this direction like shown by the arrows not only through the hole 37, or opening, respectively, but may as well flow through the net structure 33 as such. Consequently, the water may come in contact with the cleaning agent 36 thereby dissolving the latter. Therefore, it may be preferred that the net structure 33 as such is not elastically deformable but may be stiff.

In case the water flows back like described above, the water will flow through the net structure 33 only, like shown by the arrows in fig. 4c, due to the fact that the hole 37 is closed by the one way valve 35. The net structure 33 will thereby act as a filter and will only let water with dissolved cleaning agent pass. Impurities such as not dissolved particles of the cleaning agent will be hold back and may be used at a further cleaning period, for example. Such a filtering of the water may significantly enhance the cleaning efficiency.

A schematic view of a respective net structure is shown in figure 5.

A further advantage of such a net structure 33 is the fact that the net structure 33 may additionally act as a roughened area 40 like described above. As a result, this embodiment provides a plurality of advantages due to easy and cost-saving measures.

Figure 6 shows a top view onto a part of a sieve holder 10 provided with a cleaning sheet 28 according to the invention. It can be seen that the cleaning sheet 28, or its base body 30, respectively, comprises a border 42 which protrudes from the receptacle 14 in order to allow an improved handability. It can furthermore be seen that the cleaning sheet 28 completely seals the top opening of the sieve holder 10.

In figure 7, it is shown that the sieve holder 10, for example as shown in figure 6, is fixed to the sieve holder support 20, or the boiling unit 22, respectively. According to this, a cleaning method may be performed. Such a method of cleaning a boiling unit 22 of a coffee machine, thus comprises the steps of: providing the cleaning sheet 28 like described above, sealing the flow passage of the sieve holder 10 by positioning the cleaning sheet 28 at the top of the sieve holder 10 and fixing the sieve holder 10 to a sieve holder support 20. Further, water is guided to the cleaning sheet 28 and further to the boiling unit 22. Downstream the boiling unit 22, the cleaning water may be conveyed through an outlet 44.

Figure 7 further shows additional parts of the coffee machine such as two openings 46 for guiding freshly brewed coffee into a cup which may be placed on a cup holder 46.

The particular combinations of elements and features in the above detailed embodiments are exemplary only; the interchanging and substitution of these teachings with other teachings in this and the patents/applications incorporate by reference are also expressly contemplated. As those skilled in the art will recognize, variations, modifications, and other implementations of what is described herein can occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the foregoing description is by the way of example only and is not intending as limiting. In the claims, the wording "comprising" does not exclude other elements or steps, and the identified article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The inventions scope is defined in the following claims and the equivalents thereto. Furthermore, reference signs used in the description and claims do not limit the scope of the invention as claimed .

List of reference numerals

10 sieve holder

12 grip

14 receptacle

16 sieve

18 flange

20 sieve holder support

22 boiling unit

24 opening

26 boiling head

28 cleaning sheet

30 base body

31 outer region

32 restoring element

33 net structure

34 fixing element

35 one way valve

36 cleaning agent

37 inner hole

38 cleaning indicator

40 roughened area

42 border

44 outlet

46 opening

48 cup holder

Claims

1. A cleaning sheet for sealing a flowing path of a sieve holder (10) for cleaning the interior of a coffee machine, comprising

an elastically deformable base body (30) having a size being adapted to allow the flowing path of the sieve holder (10) to be sealed, wherein a cleaning agent (36) is fixed to the base body (30) .

2. The cleaning sheet of claim 1, characterised in that the cleaning agent (32) is fixed to the base body by adhesive forces.

3. The cleaning sheet according to one of claims 1 and 2, characterised in that the cleaning sheet (28) has a modulus of elasticity in a range of ≥ 1 MPa to ≤ 20 MPa.

4. The cleaning sheet according to any of the claims 1 to 3, characterised in that the base body (30) has a thickness in the range of ≥ 0,2 mm to ≤ 1 mm.

5. The cleaning sheet according to any of the claims 1 to 4, characterised in that the base body (30) is formed from plastic.

6. The cleaning sheet according to any of the claims 1 to 5, characterised in that the cleaning sheet (28) comprises at least one fixing element (34) for fixing the cleaning sheet (28) in position during use.

7. The cleaning sheet of claim 6, characterised in that the fixing element (34) is formed as thickening.

8. The cleaning sheet of any of the claims 1 to 7, characterised in that the base body (30) is formed from an elastic material.

9. The cleaning sheet according to any of the claims 1 to 8, characterised in that the base body (30) is provided with a restoring element (32) .

10. The cleaning sheet of claim 9, characterised in that the restoring element (32) is formed as a flexible air container, or as a foamed material.

11. The cleaning sheet according to any of the claims 1 to 10, characterised in that the base body (30) comprises a cleaning indicator (38) .

12. The cleaning sheet according to any of the claims 1 to 11, characterised in that the cleaning sheet (28) comprises a roughened area (40) being positioned to come in contact with at least one of a sealing of the sieve holder (10) and a sealing of a sieve holder support (20) .

13. The cleaning sheet according to any of the claims 1 to 12, characterized in that a net structure (33) is provided on the base body (30) .

14. A method of cleaning a boiling unit (22) of a coffee machine, the coffee machine comprising a sieve holder (10) connected to the boiling unit (22), comprising the steps of:

providing a cleaning sheet (28) according to any of claims 1 to 13,

sealing the flow passage of the sieve holder (10) by positioning the cleaning sheet (28) at the top of the sieve holder (10) and fixing the sieve holder (10) to a sieve holder support (20), and

guiding water to the cleaning sheet (28) and further to the boiling unit (22) .

15. A use of a cleaning sheet (28) according to any of claims 1 to 13 for cleaning the interior of a coffee machine .