EP1124472A1

EP1124472A1 - Drip-type coffee-maker comprising a water treatment device

Info

Publication number: EP1124472A1
Application number: EP99971277A
Authority: EP
Inventors: Jean-Pierre Hamon; Pascal Marlin
Original assignee: Moulinex SA
Current assignee: Moulinex SA
Priority date: 1998-10-30
Filing date: 1999-10-06
Publication date: 2001-08-22
Also published as: US6553894B1; CA2348671A1; WO2000025644A1; FR2785166B1; KR20010080929A; CN1332614A; FR2785166A1

Abstract

The invention concerns a drip-type coffee-maker comprising a water reservoir (1) supplying a water-heater with continuous circulation (6), and a device (9) for treating the water in the reservoir by means of a water-soluble scale preventive agent. The invention is characterised in that the water treating device (9) comprises an element (10) for measuring out an amount of scale preventive agent (23) which is determined on the basis of the volume of water supplied to the water-heater (6) and which is injected into the water.

Description

DRIP COFFEE MAKER COMPRISING A DEVICE

WATER TREATMENT

The present invention relates to a household drip coffee maker comprising a cold water tank supplying a continuous circulation water heater, and a device intended to treat the water contained in the tank from an anti-scale agent. soluble or in solution.

In a known coffee maker of this kind, the water treatment device comprises a cartridge which is arranged in the filling mouth of the tank while being entirely maintained above the maximum filling level of the tank, which has a cover and a perforated bottom, and which contains a soluble anti-scale agent, of the type usually constituted by one or more polyphosphate crystals, the dissolution of which can only take place during the rapid flow of water when filling the tank. However, with this type of device for treating water from polyphosphate crystals, it turns out that the amount of phosphorus that is added to the water is absolutely not precisely controlled to delay sufficiently over time. scaling of the coffee maker water heater; indeed, practice shows that in the case of a usual use of the coffee maker (for example twice a day), the quantity of phosphorus added is almost zero because the crystals do not have time to dissolve sufficiently - between two operating cycles of the coffee maker, leading to rapid scaling of the water heater, whereas in the case of intensive use of the coffee maker

(e.g. hourly), the amount of phosphorus added comes to exceed the value authorized by the legislation currently in force according to which the phosphorus concentration in water must be lower than 5 mg / 1 expressed in P ₂ 0 ₅ .

The object of the invention is in particular to remedy these drawbacks and to produce a household drip coffee maker equipped with a water treatment device from a soluble or solution-free anti-scale agent, the amount of which added in the water is perfectly controlled in accordance with the legislation in force, regardless of the frequency of use of the coffee maker and the solubility of the anti-scale agent.

According to the invention, the water treatment device comprises a device for micro-dosing of a quantity of anti-scale agent which is determined as a function of the volume of water supplied to the water heater and which is injected into water. .

Thanks to this micro-dosing device, the quantity of anti-scale agent injected into the water is now controlled with high reliability and, moreover, following its injection at a very low dose, has the unexpected effect of delaying considerably in time the scaling of the coffee maker water heater.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of nonlimiting example, with reference to the appended drawings in which: - Figure 1 is a partial schematic view. in vertical section of a coffee maker according to the invention comprising a water treatment device, the tank of the coffee maker being filled with water; - Figure 2 is a view similar to Figure 1, showing the partially emptied water tank;

- Figure 3 is a view similar to Figure 2, after complete emptying of the tank;

- Figure 4 shows, depending on the number of li- very water poured into the tank of the same coffee maker, the evolution of the time of passage of water in the coffee maker when the latter does not include a device for water treatment (curve A), when the coffee maker has a water treatment device maintained above the maximum filling level of the tank (curve B), and when the coffee maker has a water treatment device conforming to the invention (curve C); and

- Figures 5 and 6 show an embodiment of a water treatment cartridge comprising a flask of anti-scale agent in liquid form and a cap, respectively before assembly (Figure 5) and after assembly (Figure 6) of the cap on the bottle.

In FIGS. 1 to 3, only part of a drip-type household coffee maker has been represented, comprising a cold water tank 1 with a capacity defined by a maximum filling level referenced by N and of which the outlet 2 forming a mouth made in the bottom wall 4 is connected, via a non-return valve 5, to the inlet of an electric heating body formed by a water heater 6 with continuous circulation, the outlet of which feeds by an ascending tube 7 a watering spout a filter (not shown) intended to receive ground coffee and placed above an infusion collecting jug (not shown).

The coffee maker illustrated in FIGS. 1 to 3 is further equipped with a water treatment device, designated by the general reference 9, using a soluble or solution-resistant anti-scale agent, such as a complexing agent based on polyphosphates, intended to be added to water to delay scaling of the coffee maker.

The complexing agent based on polyphosphates is preferably in solid form (crystal, granules), but can also be in powder or liquid form.

According to the invention, the water treatment device 9 comprises a micro-dosing device 10 of a quantity of anti-scale agent which is determined as a function of the volume of water supplied to the water heater 6 and which is injected into water.

As shown in Figures 1 to 3, the micro-dosing device 10 is preferably removably mounted inside the tank 1 by being arranged near the outlet 2 for emptying the tank, and is suitable for rapidly injecting a low dose of anti-scale agent in the water supplied to the water heater 6 (Figure 2).

According to a preferred embodiment of the invention, the micro-dosing device 10 comprises a cartridge 12 of predetermined volume, for example of 30 cm ³ , which contains the anti-scale agent, for example a single polyphosphate crystal 14 of predetermined weight, for example 1.66 gram, and which has at its upper part a calibrated orifice 16 as well as a capillary tube

18 communicating with the interior of the cartridge 12 and rising, preferably vertically, towards the mouth

19 for filling the reservoir 1 by having an upper opening 21 which is situated above the maximum level N of the reservoir. The capillary tube 18 preferably has a cylindrical shape, of predetermined diameter, for example equal to 1.5 millimeters.

With reference to FIG. 1, when filling the reservoir 1 over a maximum water height H, determined from a level of ^ reference known as zero defined by the orifice 16 of the cartridge 12, and corresponding to a number of cups of coffee chosen by the user and generally varying from 3 to 15 cups, the poured water enters the cartridge 12 through the orifice 16 and comes into contact with the polyphosphate crystal 14 which, by dissolution, generates a solution concentrated in phosphorus, identified at 23 in Figures 1 to 3; the capillary tube 18 is filled with this concentrated phosphorus solution at substantially the same level as the water level in the tank 1, see FIG. 1.

During the operation of the coffee maker, the tank 1 begins to empty, and if the user decides to stop the emptying in progress of the tank, for example after a height of water emptied h _{ι r} as illustrated in the figure 2, which is equal to (Hh) where h is the height of water remaining in the tank from the zero reference level and varying from 0 to H, the level of the capillary tube 18 drops by the same height h _x and the solution concentrated in phosphorus 23 is ejected at a low dose through the calibrated orifice 16 of the cartridge to be mixed there with the water supplied to the water heater 6, by the known phenomenon of pumping the water heater.

Thus, the volume of concentrated phosphorus solution 23 which is added to the water supplied to the water heater during this emptying, FIG. 2, is proportional to the height of the emptied water h _λ .

More generally, in the case of a capillary tube 18 of cylindrical shape, of predetermined diameter D, the volume (V) of concentrated phosphorus solution 23 which is added to 1 'water' during the emptying of the tank 1 is given by the expression:

V = 3, 14 X (Hh) X (D) ^2/4 WHERE:

- H is the water height in the number of cups of coffee selected;

- h is the water height at filling and emptying of the tank, and varies from 0 to H.

It will be noted that the zero reference level defined by the orifice 16 of the cartridge 12 is situated, relative to the bottom wall 4 of the reservoir 1, at a predetermined height h _, for example of the order of 10 millimeters, so as to take from the cartridge 12, when emptying the tank (Figure 2), a perfectly homogeneous phosphorus solution.

After complete emptying of the reservoir 1 of the coffee maker, as shown in FIG. 3, the cartridge 12 remains full of solution concentrated in phosphorus 23, the level of the capillary tube 18 balancing at the zero reference level.

By way of purely illustrative example, taking a cylindrical capillary tube 18 of diameter D equal to 1.5 millimeters and considering a height of water H equal to 131 millimeters and corresponding to a volume of water in the tank equal to 1.4 liters, the volume of concentrated phosphorus solution which is added to the water during the complete emptying of the tank for which h = 0 is equal to 0.23 milliliters, which is particularly low.

Thus, this micro-dosing device 10 advantageously constitutes a simple, economical, precise and particularly reliable device. In addition, it makes it possible to deliver or diffuse in water an amount of complexing agent based on polyphosphates which is perfectly controlled, moreover very low, which is independent of the solubility of the polyphosphate crystal 14, and which is proportional to a water height of the tank, therefore advantageously independent of the volume of water in the tank.

In addition, by an appropriate dimensioning of its constituents, namely essentially the weight of the polyphosphate crystal 14, the volume of the cartridge 12 as well as the geometry of the capillary tube 18, this micro-dosing device 10, as a result of the injection into water of a small amount of complexing agent based on polyphosphates, makes it possible, on the one hand, to maintain a concentration or level of phosphorus in water at a value of the order of 1 mg / 1 expressed as P ₂ 0 ₅ , thus respecting fully the legislation currently in force according to which the phosphorus concentration in the treated water, at the outlet of the spout of the coffee maker, must be lower than 5 mg / 1 expressed in P ₂ 0 ₅ , and on the other hand, to delay considerably in time the scaling of the water heater at least up to 500 liters of water.

Thus, a very low concentration of phosphorus in the water supplied to the water heater of the coffee maker using this micro-metering device 10 makes it possible, surprisingly, to treat efficiently a very large number of liters of water without reaching the scale of the water heater, therefore significantly increasing the life of the coffee maker.

Referring now to FIG. 4, various experimental curves A, B and C have been shown, each illustrating the evolution of the time of passage of the water in the coffee maker, expressed by the ratio T / T ₀ where T is the time of water passage when the tank is full of water and T ₀ is also the time of water passage when the tank is full of water, but measured at the end of a first test cycle, the latter consisting of a sequence of filling the tank, followed by a sequence of operation of the coffee maker, then a sequence of cooling the coffee maker, depending on the number of liters of water poured into the coffee maker. By convention, it is considered that a coffee maker is scaled when the T / T ₀ ratio is equal to 1.2, corresponding to an increase in the water passage time of 20%. Curves A, B and C were raised by tests by feeding the same coffee maker with water of a hardness close to 44 degrees TH French.

Curve A has been noted for a coffee maker not equipped with a water treatment device and shows that scaling of the coffee maker is achieved for approximately 100 liters of water (point E).

Curve B has been noted, for its part, for the same coffee maker, but equipped with a water treatment device according to the prior art, namely a perforated cartridge maintained above the maximum level of filling of the tank and containing a 1.66 gram weight polyphosphate crystal. This curve B shows that the scaling of the coffee maker is reached for approximately 200 liters of treated water (point F).

As for curve C, it was always taken for the same coffee maker, but equipped with the micro-dosing device 10, according to the invention, as described above. For these tests, the volume of the cartridge 12 of the micro-dosing device 10 is chosen equal to 30 cm ³ , said cartridge 12 contains a single polyphosphate crystal 14 of weight equal to 1.66 grams, and the capillary tube 18 is cylindrical in shape, with a diameter equal to 1.5 millimeters. Thanks to this micro-dosing device allowing precise control of the amount of phosphorus added to the water supplied to the water heater of the coffee maker, curve C clearly shows that scaling of the water heater is not reached for 500 liters of treated water. The tests thus carried out showed the effectiveness of the micro-dosing device according to the invention, within a drip coffee maker, both in terms of the considerable delay in the scaling of the water heater of the coffee maker (by scaling to 500 liters of water), only in terms of maintaining the phosphorus concentration in water at a low value (of the order of 1 mg / 1 expressed as P ₂ 0 ₅ ) , and this by implementing a simple and reliable technology.

With reference to FIGS. 5 and 6, in which the elements identical to those described above bear the same references, a particular embodiment of the micro-dosing device will be described.

The cartridge 12, FIG. 5, consists of a bottle 26 hermetically sealed by itself at its upper part 27 and filled, under a controlled atmosphere, with a liquid solution 29 of polyphosphates at a given concentration, and a cap 30 which is removably mounted, for example by screwing, on the bottle 26.

As shown in FIG. 5, the stopper 30 is provided at its upper part with the calibrated orifice 16 and with the capillary tube 18, and internally comprises a perforating member 32 intended to pierce the upper part 27 of the bottle 26 during the screwing the cap 30, so that the orifice 16 and the capillary tube 18 both open into the perforated part of the bottle 26 (see FIG. 6). After screwing the cap 30 onto the bottle 26, the cartridge 12 thus produced is mounted inside the tank 1 of the coffee maker, as shown in FIG. 6. In addition to the fact that the cartridge 12 is of a particularly simple embodiment, it should be noted that the liquid solution 29 contained in the sealed bottle 26 is advantageously homogeneous in phosphorus and perfectly aseptic.

Claims

1. Drip coffee maker comprising a cold water tank (1) supplying a continuous circulation water heater (6), and a device (9) intended to treat the water contained in the tank from of a soluble or solution-resistant anti-scale agent (14; 29), characterized in that the water treatment device (9) comprises a device (10) for micro-dosing of an amount of anti-scale agent (23) which is determined as a function of the volume of water supplied to the water heater (6) and which is injected into the water.

2. Drip coffee maker according to claim 1, characterized in that the micro-dosing device (10) is arranged near the emptying mouth (2) of the reservoir (1) and is adapted to inject the determined quantity of anti-scale agent (23) into the water which is supplied to the water heater (6).

3. Drip coffee maker according to claim 2, characterized in that the anti-scale agent (14) being a complexing agent based on polyphosphates, the micro-dosing device (10) comprises a cartridge (12) containing l complexing agent (14), mounted inside the tank (1) and having at its upper part a calibrated orifice (16) through which water enters when filling the tank and which communicates, after passage of the in the cartridge (12), with a capillary tube

(18) of defined section which rises towards the mouth

(19) for filling the tank and which has one or upper opening (21) situated above the maximum filling level (N) of the reservoir, so that when filling the reservoir (1) with a given water level (H), the capillary tube (18) is filled of complexing agent substantially at the same level as the given water level, while during the emptying of the tank (1) over a given height of water (h _x ), the determined amount of complexing agent (23) s' escaping through the orifice (16) of the cartridge (12) to be injected into the water supplied to the water heater (6) is proportional to the given water height (h actually emptied from the tank.

4. Drip coffee maker according to claim 3, characterized in that the complexing agent (14) contained in the cartridge (12) is in solid form whose weight, as well as the volume of the cartridge (12) and the geometry of the capillary tube (18), are determined to maintain a concentration of phosphorus in the treated water at a value less than 5 mg / 1 expressed as P ₂ 0 ₅ , preferably of the order of 1 mg / 1, and to prevent any scaling of the coffee maker at least up to 500 liters of treated water.

5. Drip coffee maker according to claim 3, characterized in that the cartridge (12) comprises a bottle (26) which is hermetically sealed by itself at its upper part (27), and which is filled with l complexing agent in liquid form (29), as well as a stopper (30) which is removably mounted on the bottle (26), said stopper (30) comprising a perforating member (32) from the upper part (27) of the bottle (26) when mounting and being provided with the calibrated orifice (16) and - the capillary tube (18) which both open into the perforated part of the bottle (26).

6. Drip coffee maker according to claim 5, characterized in that the stopper (30) is mounted by screwing on the bottle (26).