HK1090266A1 - Domestic espresso coffee machines - Google Patents

Abstract

Improvements to the coffee output of domestic espresso coffee machines, comprising a pump which impels pressurised hot water so that it passes though a dose of ground coffee (or a single-dose pod) deposited in a filter (1) which is accommodated in a housing (2), which in turn is fitted in a filter holder (3) which is provided with one or more outlet pipes (4) for the infusion of coffee produced, characterised in that, in the centre of the base of this housing (2), there is secured a ball (6) valve (5) which is fitted against a helical compression spring (7) such that the ball (6) and spring (7) are thrust in a chamber (11) of the valve (5), wherein, by means of respective upper (9) and lower (10) apertures, this chamber (11) communicates with the interior of the said housing (2) and with the cavity in the said filter holder (3), which ball (6) is installed between the lower side of the said upper aperture (9) and the upper end of the said spring (7), and which spring (7) is installed between the said ball (6) and a said lower aperture (10) which has a conical shape which narrows in the downward direction and is obtained by pressure forming.

Description

Domestic Italian type espresso coffee machine

Technical Field

The present invention relates to an Espresso Coffee machine for domestic use (Espresso Coffee), comprising a pump for pushing hot water under pressure so that it passes through a quantity of ground Coffee powder or single packets of Coffee beans deposited in a filter housed in a casing which is in turn fitted in a filter holder having one or more outlet ducts for brewing the Coffee made.

In particular, the invention relates to a device for making foamed coffee (cafecreme) and to a device designed to make the quantity of coffee provided in each cup the same when the coffee machine provides coffee to two cups simultaneously.

Background

The foam coffee is prepared from an emulsion of brewed coffee and air, and the emulsion is obtained by the following steps: pushing the coffee through a fine duct provided in the housing, thereby increasing the pressure; after passing through these fine ducts, an expansion or pressure reduction occurs, which results in the brewed coffee being divided into near-spray-like droplets in which the coffee is assisted in mixing with air.

Spanish utility model No. u-200103033 is known in the art, which claims a device intended to allow a gradual adjustment of the quantity of foamed coffee; the device is composed of a body which is connected with a shell at the base thereof and forms an inner cavity, a vertical screw with an inner hole is screwed in the inner cavity, and a helical compression spring is combined in the inner cavity and pushes a ball to an upper hole which is communicated with the inner part of the shell in the body; since a greater or lesser pressure is necessary for the compression spring and the coffee outlet allowing brewing, a lesser or greater quantity of frothed coffee will be obtained by means of screws screwed into the body to a greater or lesser extent, respectively. This solution works well, but over time the screws will loosen and the amount of foamed coffee obtained will also gradually diminish.

Moreover, such coffee machines generally have a drawback. When the filter holder has two ducts and two cups must be served simultaneously from these two ducts, the amount of infusion in the two cups is often not the same and is also an uncontrolled phenomenon since this does not always occur, or does not occur in the same way; sometimes the amount of the infusion is the same in both cups and not the same at other times, in the latter case the difference in the infusion is variable. Like any liquid, or due to surface tension effects, levelness, dirtiness or irregularities on the filter holder base, due to the way the coffee flow is formed towards this base of the filter holder, due to occasional shocks in the environment surrounding the coffee machine, or for other reasons, it appears that the coffee tends to flow along one particular path and not to another.

Disclosure of Invention

In view of the above, the present invention provides an improvement in that a ball valve fitted against a helical compression spring is fixed at the center of the housing base such that balls and springs are pushed into a valve chamber communicating with the inside of the housing through respective upper and lower holes and with a cavity in the filter holder, the balls of the ball valve are installed between the lower side of the upper hole and the upper end of the spring, and the spring of the ball valve is installed between the balls and the lower hole having a tapered shape narrowing in the downward direction and obtained by means of press molding. In this proposed solution, since there is only a valve body in which the ball and spring subassembly is mounted in a limited and non-removable manner, so that the working action is always the same, there are no parts screwed in and therefore there is always the same amount of foamy coffee in the resulting coffee infusion; varying the resilient properties of the spring provides a variation of the amount of frothed coffee for a specific operating pressure of the pump and vice versa. Not only is this functional advantage obtained, but also the advantage of using fewer parts is obtained, and in addition the appearance of the new device is improved. It will be appreciated that the coffee maker is in a standby state without the filter holder mounted. This detail is important in view of the fact that household coffee machines are concerned, not industrial coffee machines.

Another improvement according to the invention consists in that the filter holder has two ducts of the same diameter as each other, so that the flow rate exiting through the two tube groups is advantageously less than the flow rate supplied by the pump, whereas the filter holder between the two ducts has an arched convex base with an apex aligned perpendicularly to the axis of the flow of brewed coffee supplied through said valve, while the ducts have a width suitable to guarantee a laminar flow of the liquid produced. The effect of this solution is that due to the fact that the entire outflow from the valve, which the conduit cannot receive, a blockage occurs, the level of the fluid then rises above the apex of the arched convex base of the filter holder; from this moment on, the coffee thus flows out through the ducts under the effect of gravity, and in view of the designed width of these ducts, the flow is highly laminar, which ensures that the flow through the two ducts is the same (the two cups are filled with coffee equally), and that the quantity of brewed coffee produced is maintained in the passage through these ducts. In addition, such a device is suitable for using a housing for a single package of ground coffee or coffee beans, which is suitable for a single or two cups of coffee, while still using a filter holder with two ducts.

Drawings

For a better understanding of the characteristics of the invention, the drawings show preferred industrial embodiments, purely illustrative and non-limiting examples.

FIG. 1 is a side view of a filter holder 3 having the proposed and shown modification according to section I-I shown in FIG. 2;

fig. 2 is a plan view from above of the filter holder 3 according to fig. 1;

fig. 3 is a view according to section III-III indicated in fig. 2, showing the housing 2 for two packets (two doses) of ground coffee;

FIG. 4 is similar to FIG. 3, but shows the housing 2 for providing a single cup of coffee;

FIG. 5 is an exploded view showing the subassembly consisting of valve 5, ball 6 and spring 7 prior to the generation of a pressure that regulates the top end of valve 5 and the push-up of valve 5 relative to housing 2;

FIG. 6 is an enlarged view of detail VI of the encircled portion of FIG. 1;

fig. 7 is an enlarged view of the detail VII shown in fig. 3.

The above figures include the following designations:

1. filter

2. Shell body

3. Filter holder

4. Filter retainer tube (3)

5. Valve gate

6. Ball bearing

7. Spiral pressure spring

8. Filter keeper arc bulge base (3)

9. Upper valve hole (5)

10. Lower valve hole (5)

11. Valve chamber (5)

Detailed Description

With reference to the above figures and numbers, the figures show a preferred embodiment of the improvement proposed by the present invention relating to an espresso coffee machine comprising (figures 1 to 4) a pump for pushing hot water under pressure so that it passes through a quantity of ground coffee powder deposited in a filter 1 housed in a casing 2, the filter 1 in turn being fitted in a filter holder 3, said filter holder 3 having one or more outlet ducts 4 (preferably two outlet ducts) for brewing the coffee made.

One of these improvements is clearly illustrated in figures 5 and 6. This improvement consists in that a ball valve 5 is fixed at the centre of the base of the housing 2, which ball valve 5 is fitted against a helical compression spring 7, so that the balls 6 and the spring 7 are pushed into a valve chamber 11 of the valve 5, wherein the valve chamber 11 communicates with the interior of the housing 2 and with the cavity of the filter holder 3 through respective upper and lower bores 9, 10, the balls 6 of the ball valve 5 being mounted between the lower side of the upper bore 9 and the upper end of the spring 7, while the spring 7 of the ball valve 5 is mounted between the balls 6 and the lower bore 10, which has a tapered shape narrowing in the downward direction and is obtained by means of compression moulding. Figure 5 shows the assembly constituting these improvements before they are assembled in an inseparable manner by means of the adjustment of the valve 5, which permanently houses inside it the ball 6 and the spring 7, thus providing a determinate working configuration, mounted in the base of the casing 2, as shown in figure 6.

In figure 7, which shows in more detail a further improvement proposed by the present invention, it can be seen that said filter-holder 3 has two ducts 4 having the same pipe diameter as each other, so as to make the flow rate exiting through the two groups advantageously smaller than the flow rate supplied by the pump, whereas the filter-holder 3 has, between the two ducts 4, an arched convex base 8, the base 8 having an apex vertically aligned with the axis of the flow of brewed coffee supplied through said valve 5, while the ducts 4 have a width suitable to guarantee a laminar flow of liquid being produced. By virtue of this provision, the flow provided by the valve 5 falls on the curved convex base 8 of the filter holder 3 at a velocity greater than the outflow rate through the duct 4, so that a spring (well) is formed, the level of which rises above the upper level of the curved convex base 8, and the flow through the duct 4 starts to occur in laminar flow under the action of gravity, and the flow rate is the same for each duct; thus, the amount of coffee provided to each cup is the same. A filter holder 3 with two ducts 4 can be used equally well for a single package of coffee powder (or a single package of coffee beans) which is supplied to a single cup via two ducts 4, or which can be supplied to two cups (fig. 4).

Claims (1)

1. An espresso coffee machine for domestic use, comprising a pump which pushes hot water under pressure so that it passes through a quantity of ground coffee powder or a single packet of coffee beans deposited in a filter (1) housed in a casing (2), the casing (2) in turn being fitted in a filter holder (3), said filter holder (3) having a plurality of outlet ducts (4) for the infusion of the coffee produced, and a ball valve (5) being fixed at the centre of the base of said casing (2), in which ball valve (5) a ball (6) is fitted against a helical compression spring (7), the ball (6) and the helical compression spring (7) being pushed into a valve chamber (11) of the ball valve (5), wherein the valve chamber (11) communicates with the interior of said casing (2) and with the cavity of said filter holder (3) through respective upper (9) and lower (10) holes, balls (6) are installed between the lower side of the upper hole (9) and the upper end of the helical compression spring (7), and a helical compression spring (7) is installed between the balls (6) and the lower hole (10) having a tapered shape narrowing in the downward direction and obtained by press molding, characterized in that the filter holder (3) has two outlet ducts (4) having the same pipe diameter as each other, so that the flow rate of coffee flowing out through the group of two outlet ducts is advantageously less than the flow rate of hot water supplied by said pump, whereas the filter holder (3) has, between the two outlet ducts (4), an arcuately convex base (8), the base (8) having an apex vertically aligned with the axis of the flow of brewed coffee supplied through said ball valve (5), while these outlet ducts (4) have a width suitable for ensuring a laminar flow of the coffee produced.