CH629947A5 - Group a volumetric for the infusion of coffee with piston volumetric control of dose of hot water. - Google Patents

Description

629947

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1. Volumetric dosing unit for the infusion of coffee, of the type comprising a piston for controlling the dose of hot water, which in its stroke for feeding the dose against the reaction of a spring is able to perform an adjustable stroke by acting on limit switch on a microswitch designed to interrupt the activation of a feed pump and switch two solenoid valves by putting the filter holder cup in communication with the outside and deactivating the feed pump, characterized in that the activation of said microswitch takes place to via magnetic means, the control means (MG) of the micro controlling the volumetric stroke of the piston is contained in the cylinder, and therefore the piston rod is without gasket, not leaving the cylinder.

2. Volumetric dosing unit according to claim 1, characterized in that the piston is associated with a magnetic mass (MG) capable of influencing by proximity effect an electric micro-switch placed adjacent the piston in an adjustable position from the outside.

Volumetric dosing unit according to claim 1, wherein the return spring of the piston is mounted inside the cylinder in which the double-acting piston works.

In the prior art, volumetric dosage units are known created by a piston sliding in a double-acting cylinder whose rod is capable of influencing an electric microswitch, in a position adjustable from the outside, according to the desired active stroke of said piston .

As soon as said microswitch is influenced by the rod (rod) exiting the piston with respect to said cylinder, the infusion phase automatically ceases, i.e. the infusion hot water supply pump is disconnected and at the same time the filter holder cup it is put in communication with the outside in order to create a partial drying of the coffee grounds by decompression.

All of this belongs to a technique known per se and this realization manufactured for years by the applicant will be exemplified below as a GROUP WITH OUTPUT AUCTION.

It is clear that this group has sealing problems as the stem physically exits the cylinder and the feed water is at about 9 atmospheres, therefore apart from the more elaborate construction it is necessary to use gaskets whose life is notoriously limited .

According to the present invention, the volumetric dosage group for coffee infusion, of the type comprising a piston for controlling the dose of hot water which in its stroke for feeding the dose against the reaction of a spring is adapted to perform an adjustable stroke acting at the end of the stroke on a microswitch designed to interrupt the activation of a feed pump and switch two solenoid valves by putting the filter-holder cup in communication with the outside and by deactivating the feed pump is characterized in that the activation of the said microswitch takes place by magnetic means, the control means of the microcontroller the volumetric stroke of the piston is contained in the cylinder, and therefore the piston rod is without gasket not leaving the cylinder.

The concept of the invention will emerge better hereinafter through the following description of a preferred embodiment of the invention given by way of non-limiting example preceded by the closest description of the art technique.

Fig. 1 is a schematic sectional view of a volumetric control unit of a known type for coffee machines with the rod coming out in the rest position (decompression of the filter holder cup);

Fig. 2 is a representation as in fig. 1 but in working position (feeding of the filter holder cup);

Fig. 3 is a representation as in fig. 1 of the control unit according to said embodiment of the invention without outgoing rod, i.e. without sealing problems for the volumetric piston rod in rest position and with the filter-holder cup in communication with the outside;

Fig. 4 is a representation as in fig. 3 m in working position (the group feed pump is operating);

Fig. 5 is a representation of the group control circuit, a circuit which in principle is the same for the known embodiment of figs. 1 and 2 and for the present inventive embodiment, according to figs. 3 and 4.

For clarity of explanation, the following description will be divided as follows:

1st: Description of the known construction (GROUP WITH OUTPUT AUCTION).

2nd: Description of the inventive embodiment in the parts which only differentiate it from the known embodiment (GROUP WITH NON-EXITING ROD THAT IS REMOTE CONTROL).

Group ad. outgoing rod A double-acting piston (PI) is sliding in the cylinder (CI), the rod of which (ST) is subject on the one hand to the reaction of a return spring (ML) and on the other hand to the pressure of the hot water supplied by the pump (PO) (see fig. 5). The stem or rod (ST) is adapted to act on a micro (MI) the position of said micro being adjustable by means of a handwheel (VO) whereby by approaching or removing the micro with respect to the end adjacent to the rod (ST) the volume of water fed to the filter-holder cup (CO) can be decreased respectively increased.

Indeed with reference to fig. 5 by pressing the control button (TA), relay 2 is energized which automatically maintains itself thanks to the contact (CCRE), so that the contacts (CORE) and (coRB) are closed by the relay, which energize the solenoid valve respectively ( EL) and (el) three-way, on one side, and the pump (PO) on the other. (FU) is a fuse and (TR) a 220-240 V transformer.

In the rest position the solenoid valve (el) puts the filter holder cup in communication with the outside causing the coffee grounds to dry up; while the valve (EL) connects the two opposite surfaces of the piston (PI) recovering the previously introduced hot water.

Conversely, the passage of hot water to the filter-holder bowl is prohibited.

When the button is pressed, the two three-way valves (el, EL) both switch so that on one side the supply of the cylinder is allowed while the passage of hot water to the group is allowed (communication with the outside being intercepted). As soon as the rod (ST) touches the microswitch, the relay is de-energized, therefore the power supply of the two solenoid valves which switch to the rest position specified above is interrupted, so on the one hand the piston under the influence of the return spring it returns to the initial position and on the other the group is put in communication with the atmosphere in order to dry up the coffee grounds. In this phase the hot water contained in the chamber A feeds the chamber B adjacent to the rod activating the micro, all according to a known technique.

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629947

It is clear that the rod (ST) being mounted exiting involves sealing problems and therefore the presence of gaskets (not shown).

Control unit for the dose of water with piston rod not coming out of the cylinder Same parts or with equivalent function have been recalled with the same references underlined. The piston {PI) has a magnetic mass (MG) which is therefore capable of influencing a Reed contact (MI) as a function of proximity. The position of the Reed is variable via the handwheel (VO) as indicated. Therefore in this embodiment the control means of the grain is completely contained in the cylinder (CI) and any sealing problem is solved. Furthermore, the operation is faster and more precise and without appreciable friction.

5 The functioning of the group is the same as that outlined above and therefore please refer to the previous paragraph.

By the inventive concept the same effect can be obtained with proximity contacts, with micro-sensitive ones etc. I always remaining firm the principle of a magnetic command (remote control) without physical contact of the command rod with the micro.

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2 drawings sheets