WO2009030751A2 - Part for a hydraulic circuit of a machine for preparing drinks that comprises a coating - Google Patents

Abstract

Part for a hydraulic circuit of a machine for preparing drinks that is intended to be positioned in contact with a liquid that goes into the composition of the drink, the part being at least partly covered with a coating that comprises a layer of inorganic carbon comprising synthetic carbon of the hard amorphous carbon type.

Description

 "PIECE FOR HYDRAULIC CIRCUIT OF MACHINE FOR PREPARATION

BEVERAGE COMPRISING A COATING

The present invention relates to a piece for hydraulic circuit of machine for preparing drinks.

It finds particular application in the field of machines for preparing drinks that infuse a product with a hot liquid. This is the case of EXPRESSO type coffee machines. It may also apply to the production of beverages from other materials such as tea or cocoa.

It has been found that as preparation cycles, the quality of beverages obtained with the same machine deteriorates. This disadvantage is all the more prejudicial as the requirements of consumers for the taste quality of this type of beverage tend to increase. It has also been found that this degradation of the taste of beverages obtained comes from a decrease in the performance of the machine.

In an attempt to overcome this reduction in performance, routine maintenance of the hydraulic circuit of the machine is usually carried out. These operations consist in replacing or disassembling and cleaning a greater or lesser number of parts constituting the hydraulic circuit of the machine.

These parts may include essential machinery parts such as the boiler, pump or pipe portions of the circuit. These operations are long, tedious, expensive and induce a downtime of the machine which in addition to causing a certain inconvenience for the user causes significant economic damage if the machine is the subject of professional exploitation. Despite these frequent maintenance operations the quality of the drinks obtained tends to degrade during the life of the machine.

Moreover, many solutions have been developed to enhance the efficiency of the filters usually arranged in hydraulic circuit inlet to improve the quality of the liquid used for the preparation of the drink. However, these filters have not proved sufficiently effective to stabilize over time and significantly the quality of beverages obtained.

There is therefore a need to improve the stability of performance of beverage machines.

To meet these needs, there is provided according to the present invention a piece for a hydraulic circuit for a machine for preparing beverages intended to be positioned in contact with a liquid used in the composition of the beverage, the part being at least a part covered a coating comprising an inorganic carbon layer comprising amorphous hard carbon type synthetic carbon.

The applicant has found that this type of coating has very good anti-adhesion properties. Such a coating particularly effectively limits scale deposits that tend to accumulate on parts of conventional hydraulic systems. However, the applicant has identified that in conventional hydraulic circuits the degradation of the taste of the drink is largely due to limescale deposits accumulating on certain parts placed in contact with the liquid flowing through the hydraulic circuit. Indeed, the accumulation of limestone tends to change the dimensions of certain passages of the circuit, which consequently causes a change in the liquid flow and substantially disturbs the process of preparation of drink. There is a drift in the taste and consistency of coffee.

The invention, by preventing the accumulation by adhesion of scale-like deposits on parts of the circuit thus contributes to preserving the critical dimensions of these same parts and ensures a maintenance of the performance of the hydraulic circuit. In addition, the applicant has found that even in small quantities, these deposits of limestone and scale tend to form a thermally insulating layer on the surfaces of the rooms on which they accumulate.

The applicant has also identified that the thermal equilibrium of the known hydraulic circuits can be substantially disturbed if the thermal conductivity of certain parts is changed.

However, it has been found that a drift of even a few degrees of the temperature of the liquid in the hydraulic circuit causes a significant deterioration of the taste of the drink obtained. Indeed, to obtain an optimal taste, the temperature of the liquid must be perfectly controlled particularly during the infusion with regard to the preparation of coffee.

Furthermore, the applicant has identified that this coating has good thermal conductivity and that the latter is substantially superior to known release coatings and made of titanium or Teflon. Consequently, this characteristic of the invention contributes to preserving the heat exchange necessary for the beverage making process and contributes effectively to maintaining the thermal regime of the hydraulic circuit.

The invention, by preventing the adhesion accumulation of scale deposits on parts of the circuit and preserving the thermal conductivity of these same parts, thus contributes to preserving the thermal performance of the hydraulic circuit and improves the control of the temperature of the liquid. .

As will be detailed later, among these parts involved in heat exchange, there is the exchanger which aims to promote heat exchange between cold water from the tank and hot water contained in the boiler.

This is also the case of the infusion head which, in the professional machines, has the function of ensuring thermal regulation of the infusion chamber by thermal conduction between the infusion head and a thermal stabilization block. The part according to the invention may further optionally have any of the following characteristics:

the layer has an amorphous structure comprising graphitic clusters in a diamond-like matrix,

the carbon is added with silicon, the atomic proportion Si / (Si + C) in the layer, varies from 5 to 50% and more particularly from 10 to 40%, it contains at least one other doping agent chosen from boron, phosphorus, argon, nitrogen and fluorine whose content is lower than the silicon content,

it comprises a substrate on which the coating is deposited, the substrate being made of a material chosen from metals, glasses, semiconductors, ceramics and organic materials,

the substrate is made of a material chosen from metals, glasses, semiconductors, ceramics and organic materials,

the substrate is made of a material chosen from iron, steels, aluminum, nickel, titanium, cobalt, chromium, alumina ceramics, silicon, germanium, glass and plastics such as polyethylene, polytetrafluoroethylene and polyurethane,

- It forms a hand shower, or an infusion plate, or a pipe portion for the liquid, or at least a portion of an infusion chamber in which the liquid is intended to ensure the infusion of a product, or a thermal stabilization block, or a spring, or at least a portion of an exchanger, or a filter,

It is also provided according to the invention a machine hydraulic circuit for preparing beverages comprising at least one part according to any one of the preceding characteristics.

In addition, there is provided according to the invention a method of manufacturing a piece for hydraulic circuit machine for preparing drinks to be positioned in contact with a liquid used in the composition of the drink, in which is deposited on at at least part of the part a coating comprising an inorganic layer comprising amorphous hard carbon type synthetic carbon.

Many hydraulic circuit parts, including those presented hereinafter by way of example may be the subject of the present invention. Each of the parts according to the invention comprises a substrate and a coating. In the rest of the invention, the term "substrate" refers to the layer on which the coating is deposited. Thus, the invention naturally extends to parts comprising a plurality of layers, at least one of which is partially covered with a coating comprising a doped amorphous carbon layer.

The coating can be deposited on the entire surface of the part. It will also be possible to deposit this coating only on the whole or only on a portion of the portion of the room intended to come into contact with the liquid. Additional features of this coating and its deposition mode will now be detailed.

The coating has an "amorphous carbon" layer, also referred to as "amorphous hard carbon". This type of coating combines a graphitic matrix with a diamond type matrix.

It is especially proposed by the company APPLICATIONS LAVES THIN ACM under the brand CASIDIAM. The composition and the method of obtaining this type of coating are described in detail in the patent application filed June 12, 1991 under the number FR 91 088 1 1 and published January 15, 1993 under the number FR 2 678 955.

Thus, for each of the parts, the substrate is coated on at least a portion of its surface with a coating comprising an inorganic layer comprising synthetic carbon of the amorphous hard carbon type. The layer comprises graphitic clusters in a diamond-like matrix. Advantageously, the carbon is supplemented with silicon. This addition of silicon facilitates the obtaining of a regular synthetic structure, homogeneous and approaching a diamond-like structure.

The silicon content can be substantially uniform over the entire thickness of the coating. This content may also decrease from the deep layers to the superficial layers of the thin layer. It can also be provided that said thin layer comprises surface layers whose silicon content is zero.

Preferably, the atomic proportion Si / (Si + C) in the thin layer varies from 5 to 50% and more particularly from 10 to 40%.

Optionally it may also be provided that said thin layer contains at least one other doping agent selected from boron, phosphorus, argon, nitrogen and fluorine whose content is less than the silicon content.

Advantageously, the substrate is made of a material chosen from metals, glasses, semiconductors, ceramics and organic materials. More specifically, provision may be made to produce the substrate made of a material chosen from iron, steel, aluminum, nickel, titanium, cobalt, chromium, alumina ceramics, silicon, germanium, glass and plastics such as polyethylene, polytetrafluoroethylene and polyurethane.

According to an exemplary embodiment of the invention, obtaining the coating on at least a portion of the surface of the substrate is carried out by the plasma-assisted chemical vapor deposition method, a thin layer of amorphous carbon silicon added, starting from a gaseous reactant containing silicon, optionally mixed with a gaseous hydrocarbon if the silicon-containing gas does not contain carbon.

For some parts whose material does not make it possible to obtain a thin adherent layer, it is possible to provide an intermediate layer forming a substrate and intended to receive the coating in order to promote the cohesion of the latter on the part. Thus, it may for example provide an intermediate layer of aluminum between the coating and a piece of copper, brass or any other copper alloy. It will of course be necessary to choose a conductive intermediate layer if the part is intended to participate in heat exchange. Preferably, the silicon-containing gas is an organolisane which corresponds to formula (1)

R1 I

R2 - Si - R4 (1) I

R3 wherein R1, R2, R3, R are independently -H or an alkyl group having 1 to 3 carbon atoms, it being understood that at least one of R1 - R4 is different from H. Optionally, The silicon content of the deposit is regulated by the choice of the gaseous reagent, as a function of the Si / (Si + C) ratio of said gaseous reactant.

Also optionally, said gaseous reactant comprises SiF4 and also contains at least one doping agent chosen from argon and nitrogen and / or a gaseous precursor of a doping agent chosen from boron, phosphorus and fluorine. more precisely from N2F4, CF2, SiF4, PF5, PH3 and BF3.

As described above, a piece according to the invention, by limiting the accumulation of limescale in the hydraulic circuit, helps to preserve the flow and heat exchange of the latter and effectively contributes to maintaining the quality of the drink to prepare. In addition, this type of coating because of these anti-adhesion qualities also limits the accumulation of deposits of substances other than limestone or scale such as greasy substances. In particular, during the preparation of coffee, a substance derived from coffee, the coffee is deposited on the surfaces of the parts with which it comes into contact. However, the applicant has found that in known circuits this substance tends to fix the limestone on the surfaces of the circuit parts which tends to reduce the effectiveness of the cleaning agents used during maintenance operations and therefore promotes the accumulation of limestone. By limiting the deposits of coffee, the invention thus reinforces the advantages mentioned above and associated with the limitation of limescale deposits.

In addition, the inorganic nature and homogeneity of the coating make it possible to provide this anti-adhesion property while having a relatively low coating thickness. Indeed, the thickness of the coating is limited to about 2 to 8 microns and more particularly 2 to 5 microns, while that of traditional anti-adhesive coatings is generally of the order of 10 to 12 microns.

In addition, as previously presented, the coating can be deposited on the circuit parts in a simple and inexpensive way. Thus the invention can be applied to existing machines. It does not involve the design of new parts and requires only to deposit on conventional parts the coating detailed above to obtain a part object of the present invention.

Moreover, such a coating facilitates the cleaning of the hydraulic circuits. It thus makes it possible to reduce the consumption of cleaning agents, to reduce the duration and the efforts of the maintenance operations.

In addition, the applicant has found that in known circuits the taste quality of the beverage obtained is substantially degraded by the migration into the liquid particles from materials usually constituting parts of conventional hydraulic circuits. However, the amorphous hard carbon coating of the parts according to the invention constitutes a very effective chemical barrier against ion migrations, preventing any corrosion of the coating itself, or of the substrate by the liquid. Moreover, in conventional circuits, corrosion tends to increase the porosity of the surfaces of the parts, which contributes to facilitating the accumulation of scale. In addition, this coating is highly resistant to acids, alkalis, solvents and generally aggressive cleaning agents.

In addition, the coating comprising the amorphous carbon layer added with silicon deposited on an object object of the present invention has excellent organoleptic qualities. Thus, the invention makes it possible to preserve the quality of the drink obtained and to preserve the integrity of the machine during the operating cycles of the machine.

Other features, objects and advantages of the present invention will appear on reading the detailed description which follows. The accompanying drawings given by way of non-limiting example illustrate hydraulic circuit portions comprising parts for which a coating according to the invention is particularly advantageous:

Fig. 1 shows an exploded view of a machine brewing chamber assembly for receiving coffee in the form of a pod.

- Figure 2 shows an exploded view of a boiler assembly of domestic coffee machine.

- Figure 3 is a diagram of a part of hydraulic circuit of professional coffee machine. The list of parts cited below as an example is not exhaustive and it is obviously possible to wear other parts equipping the hydraulic circuit. In particular, the number, function and structure of the parts of a hydraulic circuit vary substantially according to the different models of beverage preparation machine. Furthermore, although the following examples relate more particularly to coffee machines, the invention can also be applied to all types of beverage preparation machines providing for circulation of a liquid.

The hydraulic circuits generally comprise an infusion chamber intended to accommodate the product to infuse and to allow infusion of the latter by the liquid flowing through the circuit. For this purpose, an infusion chamber generally comprises a part usually referred to as a "shower" and having a wall pierced with several orifices. A handshower 1 is illustrated in FIG. 1 and has the reference 1. A first face of the wall of the handshower is arranged facing the liquid coming from the boiler and a second face, opposite the first face, is arranged with respect to the product. to infuse. The orifices allow the passage and distribution of the liquid in the brewing chamber.

An infusion chamber also has a plate carrying at least one hole. A plate referenced 2 is shown in Figure 1. This plate 2 comprises a first face disposed with respect to the product to be infused and a second face disposed opposite the output of the hydraulic circuit. This plate 2 is in particular intended to retain the product in solid form in the chamber 11 and to let the infused product escape in the liquid state.

The sections of the orifices and the hole are determined very specifically and directly influence the flow rates of liquid entering and leaving the brewing chamber. These flow rates directly affect the quality of the drink obtained. The hole is partly responsible for the appearance of a coffee emulsion giving rise to the foam present on the surface of the coffee and appreciated by consumers. Moreover, this hole provides an essential function of depressurization of the hydraulic circuit.

Depositing the above detailed coating on the hand shower 1 and / or on the plate 2 so as to obtain one or more pieces according to the invention, makes it possible to limit the accumulation of limestone at these orifices and / or these holes . The invention thus contributes to preserving the quality of the drink.

Furthermore, the hand shower 1 and / or the plate 2 may be in contact with a thermal stabilization block. This block, usually made of metal, is intended to store a large amount of heat and to return a portion to the parts of the brewing chamber with which it is in contact. The thermal stabilization block thus aims to maintain the brewing chamber at a constant temperature regardless of the frequency of use of the hydraulic circuit.

Parts according to the invention acting shower 1 and / or plate 2 have a very good thermal conductivity and thus limit scale accumulation while preserving the thermal performance of the hydraulic circuit over time. The applicant has indeed found that the inorganic coating has a thermal conductivity much higher than traditional non-stick coatings and especially traditional coatings of organic nature. It will also be possible to deposit the previously detailed coating on a filter usually disposed at the boiler outlet so as to obtain a part according to the invention. Such a filter bears the reference 3 in FIG.

In conventional machines, it often happens that this filter 3 is scaled which leads to a deterioration of the quality of the coffee to see a blockage of the hydraulic circuit. A filter 3 according to the invention makes it possible to limit considerably the aforementioned and related drawbacks of scale buildup.

In addition, the invention can be applied to a valve valve assembly usually present in conventional machines. Such a set for a rating valve is referenced 4 in FIG. 2. This set for calibration valve 4 usually comprises a spring 5 and a valve 6 capable of closing a liquid passage orifice under the thrust of the spring 5. This assembly for The function of the valve is to control the pressure at which the liquid is injected into the brewing chamber 16. The tightness ensured by the valve 6 and the tension of the spring 5 must therefore be perfectly controlled. A valve 6 and / or a spring 5 constituting parts according to the invention makes it possible to limit any accumulation of scale. These parts thus preserve the tightness and mobility of the valve assembly. So the latter can ensure optimal control of the pressure at which the liquid is injected into the brewing chamber 16.

It may also be provided that a part according to the invention acts as a reservoir spring ensuring the sealing of the conduit establishing a fluid communication between the pump and the reservoir.

In conventional hydraulic systems, excessive scaling of the spring can impede pump supply and adversely affect the integrity of the hydraulic system.

In addition, it will be possible to coat according to the invention the parts which constitute the exchangers of the professional machines and which participate in heat exchange. An exchanger 10 is shown in FIG. 3. An exchanger 10 generally comprises a chamber 1 1 having a wall whose external face is in contact with a hot liquid contained in the boiler 13 and whose internal face accommodates the liquid intended to be brought to infusion temperature.

The exchanger 10 also comprises a metal through tube 12 immersed in the liquid contained in the chamber and for supplying the chamber 1 1 of the exchanger with cold liquid. The exchanger 10 has an outlet allowing the liquid brought to the brewing temperature to be discharged to the brewing chamber 16.

Thus, the heat exchanger 10 provides heat exchange between, on the one hand, the liquids in contact on either side of the wall of the chamber 11 and, on the other hand, between the liquids in contact on either side of the chamber. inside and outside the tube 12 through.

The scaling of the wall of the exchanger 10 and / or the tube 12 through leads to a change in the thermal regime of the exchanger 10. However, the professional machines must be able to provide a large number of coffees continuously. A decrease in the thermal regime of the machine inevitably leads to a drift in the quality of the drinks obtained.

Furthermore, excessive scaling of the exchanger 10 generally leads to a complete closure of the latter which requires immobilization and complete disassembly of the hydraulic circuit.

The exchanger 10 comprising parts according to the invention thus makes it possible to limit the accumulation of limestone and contributes effectively to preserving the thermal equilibrium of the hydraulic circuit over time. Such an exchanger thus preserves the quality of the beverages obtained.

In addition, part of the water at infusion temperature at the outlet of the exchanger

10 is intended to supply heat to the aforementioned thermal stabilization block 14 and shown in FIG. 3. This heat can then be returned to the liquid by the block 14 at the level of the infusion chamber 16. This block 14 thus allows to regulate the infusion temperature to ensure optimal infusion conditions. This heat input is made during the passage of the liquid in ducts 15 carried by the block. Scaling of these ducts disrupts this particularly sensitive thermal equilibrium. A thermal stabilization block 14 at least part of the ducts 15 are covered with the coating detailed above allows to play its role of regulator without being subject to the drawbacks associated with the accumulation of scale.

The present invention is not limited to the embodiments described above, nor the parts mentioned in example but extends to any embodiment in accordance with his spirit.

REFERENCES

1. Handshower 2. Plate

3. Filter

4. Set for tare valve

5. Spring

6. Check valve 10. Exchanger

1 1. Room

12. Tube

13. Boiler

14. Stabilization block 15. Ducts

16. Brewing chamber

Claims

1. Part for a hydraulic circuit for a machine for beverage preparation intended to be positioned in contact with a liquid used in the composition of the beverage, characterized in that it is at least partly covered with a coating comprising an inorganic layer comprising synthetic carbon of hard amorphous carbon type. 2. Part according to the preceding claim, characterized in that the layer comprises graphitic clusters in a diamond type matrix. 3. Boiler (1) according to any one of the preceding claims, characterized in that the carbon is supplemented with silicon. 4. Part according to claim 1, characterized in that the atomic proportion If / (Si + C) in the layer, varies from 5 to 50% and more particularly from 10 to 40%. 5. Part according to claim 1, characterized in that it contains at least one other doping agent selected from boron, phosphorus, argon, nitrogen and fluorine whose content is less than the silicon content. 6. Part according to claim 1, characterized in that it comprises a substrate on which is deposited the coating and in that the substrate is made of a material selected from metals, glasses, semiconductors, ceramics and organic materials. 7. Part according to claim 6, characterized in that the substrate is made of a material selected from iron, steel, aluminum, nickel, titanium, cobalt, chromium, alumina ceramics, silicon, germanium, glass and plastics such as polyethylene, polytetrafluoroethylene and polyurethane. 8. Part according to any one of claims 1 to 7, characterized in that it forms a hand shower (1), or an infusion plate (2), or a pipe portion for the liquid, or at least one portion of an infusion chamber (16) in which the liquid is intended to infuse a product, or a thermal stabilization block (14), or a spring or at least a portion of an exchanger ( 10), or a filter (3). 9. Hydraulic machine circuit for beverage preparation comprising at least one piece according to any one of the preceding claims. 10. A method of manufacturing a piece for hydraulic circuit machine for preparing drinks to be positioned in contact with a liquid used in the composition of the drink, characterized in that it is deposited on at least a portion of the a coating comprising an inorganic layer comprising amorphous hard carbon type synthetic carbon.