DE2852644A1 - VOLUMETRIC DOSING UNIT IN PARTICULAR FOR COFFEE MACHINES - Google Patents

Description

28526U "3 - ': -5 EET 1978

Patent attorney

Company BREVETTI GAGGIA S., p.A., Robecco SuI Naviglio, Milan, Italy,

Volumetric dosing unit ina special for Coffee machines,

Priority i Italy, from January 31, 197Ö - No, 19Ö19 A / 7Ö

According to the state of the art, volumetric metering units known consisting of a piston in a cylinder with double action, the rod of which is a microswitch actuated. The position of the microswitch is from the outside

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is adjustable, depending on the active desired stroke of the piston mentioned.

As soon as the microswitch is acted upon by the piston rod emerging from the cylinder, it interrupts the infusion phase, i.e. the feed pump for the hot infusion water is no longer supplied and At the same time, the filter support shell is connected to the outside air in order to partially remove the coffee grounds through negative pressure to dry.

All of this is part of the known state of the art and can be referred to as a UNIT WITH "ESCAPING" ROD,

Such a unit obviously has disadvantages in terms of sealing. In fact, the rod emerges from the cylinder housing and the supply water has a pressure of about 9 Attt, which, apart from the greater structural effort, necessitates the use of known sensitive and expensive seals.

The invention now proposes a unit that in a practical and absolutely safe manner, the above ■ Eliminates disadvantages, eliminating any seal.

The volumetric unit for coffee infusion is constructed in such a way that a piston is provided which, on its working stroke, is adjustable against the force of a spring

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Covered the way, with its rod at the end of the stroke acted upon a microswitch to interrupt operation a feed pump and switching of electrovalves, whereby the filter support shell is in connection with the outside air comes (drain), is characterized in that the said microswitch is actuated magnetically.

An exemplary embodiment of the invention is shown schematically in the drawing. It show no

Fig. 1 shows schematically in cross section a volumetric Control unit for coffee machines with protruding rod in rest position (decompression 'the Filter holder).

FIG. 2 shows an illustration according to FIG. 1, but in the working position (feeding of the filter support shell).

3 shows a representation according to FIG. 1 of the inventive Control unit, i.e. without sealing problems in. Idle position and with filter holder after externally connected,

4 shows an illustration according to FIG. 3, but in the working position in which the feed pump of the unit is in operation.

Fig. 5 is a schematic representation of the electrical control circuit of the unit, this Control circuit basically the execution according to Figures 1 and 2 as well as the

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embodiment according to the invention according to figures 3 and 4.

With reference to Figures 1, 2 and 3 is known in a Unit with exiting rod provided with a double-acting cylinder a piston (PI) provided, its stagne (ST) on the one hand by a return spring (ML) and on the other hand by the pressure of the pump (PO) (see Fig. 5) fed hot water is applied. The rod (ST) acts on you Microswitch (Ml), the position of this microswitch can be adjusted by a handwheel (VO), whereby the Approaching or removing the microswitch at or from the end of the dosing piston rod (ST) facing it the flow rate of the water flowing to the filter support bowl (CO) can be increased or decreased,

After pressing the push button button (TA), as shown in Fig. 5 is shown, namely the relay (2) is energized, which remains automatically attracted by the holding contact (CC),

RE RE whereby the relay contacts (CO) and (co) getting closed. The latter respectively excite the three-way electrovalve (EL) or (el) on the one hand and on the other hand the pump (PO).

With (FU) a fuse is designated and with (TR) a 220-240 V transformer.

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In the rest position, the solenoid valve (el) controls the Filter carrier shell connected to the outside air, whereby the coffee grounds are partially dried, as is well known, while the valve (EL) the two opposite Recovers areas of the previously let in hot water. The reverse is the flow of the hot Water blocked to the filter holder.

When the pushbutton is pressed, the two D. three-way valves (el-EL) switched over, which on the one hand the supply of the piston is released and on the other hand the flow of hot water to the unit takes place or the Connection to the outside air is blocked. As soon as the piston rod (ST) touches or actuates the microswitch the relay is de-energized and the power supply to the two solenoid valves is interrupted, which is now the above-mentioned rest position take in. As a result, on the one hand, the piston returns to the starting position under the action of the return spring and on the other hand, the unit is connected to the outside air in order to dry the coffee grounds.

The hot water ° feeds in room (A) next to the the piston rod (ST) lying space (B), as already. _ .. naoh. state of the art is known.

Of course, the rod (ST) is conditioned by the emerging arrangement sealing problems and thus the

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Use of seals (not shown).

With reference to FIGS. 3, 4 and 5, the same parts or parts with functions corresponding to FIGS. 1, 2 and 5 in the embodiment according to the invention are denoted by the same reference numerals below.

The piston (PI) consists of a magnetic mass (MG) and acts on a reed contact (MI) when approaching » The position of the micro reed (MI) can be regulated by a handwheel (VO) as indicated. According to this embodiment the rod (ST_) is completely in the cylinder (CI) included and thus eliminates any sealing problem. This makes the mode of operation more precise and faster. the Rod (ST) can of course even be omitted as it has no effect of its own

The operation of the unit is the same as described above, and can therefore be found in the section above.

To achieve the same effect, it is of course possible to provide proximity contacts, responsive microswitches, etc., always maintaining the principle of contactless magnetic control.

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Claims (1)

-5 EET 1978 ßuxacbsr * rrci ^ 9 / Ui ^:. ·· Ί CoJSi / 31 83 PATENT CLAIMS l.i Volumetric unit for coffee infusion in the Kind of constructed that a piston is provided which, on its working stroke, counteracts the force of a spring covered adjustable distance, with its rod at the end of the stroke acted upon a microswitch to interrupt the Operation of a feed pump and switching of electrovalves, whereby the filter support shell with the outside air in Connection comes (drain), is characterized by 1/0568 ^! ORIGINAL INSPECTED that the operation of said microswitch is magnetic he follows . In 2, A Steueragaregat according to claim 1 characterized in that the piston coaxially a <■ magnet mass is associated with the electrical switch such as a reed switch adjacent to said piston actuated lying on approach. 3. A control unit according to claim 1, characterized in that the piston rod from the double-acting Cylinder does not emerge and the return spring of the piston inside the double-acting Cylinder lies. T he P at e & fci & nwa It 909831/0568