The present invention relates to an electric valve device, used in particular, but not solely, in household appliances, such as washing machines or dishwashers.

More specifically, the invention relates to an electric valve device of the type comprising a hollow body with an inlet and an outlet for a flow of fluid, in particular a liquid, between which, in said body, a chamber is defined wherein a (first) valve seat is provided, a (first) obturator moveably mounted in said chamber and cooperating with said

(first) seat to control the communication between the inlet and the outlet, and

a moveable member coupled with said (first) obturator and displaceable towards and away from said (first) valve seat and arranged to be controlled by means of an electrically operable actuator, such as a solenoid or a wax actuator, carried by said body.

In such an electric valve device, it may happen that particles, impurities and other granules carried by the liquid become "pinched" between the obturator and the associated valve seat. When this occurs, the hydraulic seal between the obturator and the seat may become distorted, and there may be undesired leakage of liquid.

One object of the present invention is to provide an electric valve device adapted to overcome the drawback outlined above of solenoid valve devices according to the prior art.

This and other objects are achieved according to the invention with an electric valve device of the initially defined type, characterized primarily in that in said body, a second valve seat is formed, staggered with respect to said first valve seat along the direction of displacement of the first obturator, and in that said first obturator is connected to a second obturator displaceable from and towards said second valve seat;

the arrangement being such that said first and second obturators are jointly displaceable away from and towards the corresponding seats, with which they define a first and respectively a second valve fluidically in series with one another, both controllable through said electrically operable actuator. Further features and advantages of the invention will become apparent from the detailed description that follows, provided by way of non-limiting example with reference to the accompanying drawings, in which:

Figure 1 is a partial sectional view of an electric valve device according to the present invention, shown in the closed condition;

Figure 2 is a partial sectional view showing the electric valve device of figure 1 in the open condition;

Figure 3 is a partial sectional view of another electric valve device according to the present invention, shown in the closed condition;

Figure 4 is a partial sectional view showing the electric valve device of figure 3 in the open condition;

Figure 5 is a partial sectional view of another electric valve device according to the present invention;

Figure 6 is an enlarged view of the portion of figure 5 indicated by the arrow VI; and Figure 7 is a partial sectional view showing the electric valve device according to figures 5 and 6 in the open condition; and

Figure 8 is a partial sectional view of another electric valve device according to the present invention;

In figures 1 and 2, an electric valve device according to the present invention is indicated collectively at 1.

This electric valve device comprises a hollow body, indicated collectively at 2, which in the exemplary embodiment illustrated comprises an upper element 2a and a lower element 2b, coupled together in a liquid-tight seal by the interposition of a sealing O-ring 3.

The 2nd and 3rd elements may be made for example of a molded plastic material.

The body 2 has two conduits 4 and 5, which may serve either as input or output for a flow of fluid, especially a liquid.

Between these conduits 4, 5, in the body 2 a chamber 6 is formed. As better seen in figure 2, in the chamber 6, an upper valve seat 7 and a lower valve seat 8 are made with vertical space left between them.

Preferably, although not necessarily, the seats 7 and 8 are coaxial with each other.

In the illustrated embodiment, the seats 7 and 8 are both made in the lower element 2b of the body 2.

In the upper element 2a of this body, a tubular formation 9 is made, which extends essentially upwards, coaxial with the seats 7 and 8. The upper end of the tubular formation 9 is closed, while the lower end is open and opens into the chamber 6.

Around the tubular formation 9 of the body 2, a control coil or solenoid 10, made in a manner known per se with insulated electric wire, is mounted in a fixed position. The leads of this coil or solenoid are connected to respective terminals 11 (only one of which is visible in the drawings), for example in the form of lamellar plugs, for connection to a control circuit (not shown).

In the embodiment according to figures 1 and 2, inside the chamber 6, a tubular extension 2c extends from the lower element 2a of the body 2.

Inside the tubular portion 9 of the element 2a of the body 2, a ferromagnetic member 12 of a substantially cylindrical general shape is mounted in a vertically movable manner.

The lower end of the member 12 forms a terminal head 12a, joined to the rest of the member 12 by a portion of reduced diameter, in the form of a neck, 12b.

Above the terminal head 12a and around the neck 12b of the member 12, the upper end of an obturator assembly indicated collectively at 13 is attached.

In the embodiment illustrated in figures 1 and 2, the obturator assembly 13 comprises an upper body 14, the upper end of which is attached to the neck 12b of the member 12, and the lower end of which has an axial cavity directed upwards, in which the upper end of a second body 15 is planted by force, protruding downward in the direction of the conduit 5.

The body 14 in its intermediate portion has a protrusion 14a which extends radially outwards in the manner of a flange. Immediately below this formation 14a, the body 14 has a peripheral annular groove in which a sealing ring member 17 in the form of a flat ring is engaged and held, intended to cooperate operationally, in the manner of an obturator, with the upper valve seat 7.

The lower distal end of the body 15 has a terminal formation 15a projecting radially outward.

Around an intermediate portion of the body 15 and above its terminal formation 15a, a second sealing element 18 is engaged, intended to cooperate in the manner of an obturator, with the lower valve seat 8.

Inside the tubular element 2c of the body 2, a helical spring 19 is interposed between said body 2 and the flange-like formation 14a of the body 14 which tends to push down the assembly formed by the member 12 and by the obturator assembly 13, towards the position of figure 1 , in which the obturators 17 and 18 obstruct the valve seats 7 and 8 associated with them respectively.

Preferably, in this condition, the obturator 18 is elastically deformed upward, as a result of its engagement with the valve seat 8, so as to be resiliently loaded against this seat. Consequently, if granules are "pinched" between the obturator 17 and the associated valve seat 7 so as to keep the assembly formed by the member 12 and the obturator assembly 13 slightly raised with respect to the nominal closed position of figure 1, the obturator 18 is still able to ensure an effective sealing action against the associated valve seat 8.

Appropriately, the radial extension 17 of the obturator is such that its support surface against the associated valve seat 7 is lower than the extension of the contact surface between the obturator 18 and the associated valve seat 8. In this way, the probability that granules may be pinched between the obturator 17 and the valve seat 7 is reduced. In the de-energized condition of the control coil or solenoid 10, the electric valve device 1 assumes the closed condition illustrated in figure 1.

When an electric current is made to circulate in the coil or solenoid 10 in a predetermined direction, the magnetic field correspondingly developed attracts the member 12 towards the other and the obturator assembly 13 connected to it, against the action of the helical spring 19, which becomes compressed. The electric valve device 1 switches into the open condition shown in figure 2, in which both obturators 17 and 18 are far from the corresponding valve seats 7 and 8, and a liquid flow is allowed between the conduits 4 and 5.

When the passage of current in the coil or solenoid 10 is interrupted, the assembly formed by the member 12 and the obturator assembly 13 returns to the closed condition of figure 1, under the action of the spring 19.

With reference to figure 2, in the open condition of the electric valve device, the flange-like formation 14a of the obturator assembly 13 appropriately engages the lower end of the tubular appendage 2c of the body 2. In this way, the exposure of the helical spring and the member 12 to the flowing fluid is limited between the conduits 4 and 5.

The electric valve device 1 described above with reference to figures 1 and 2 allows effectively overcoming the drawback of the devices according to the prior art, outlined in the introduction of the present description.

Figures 3 and 4 illustrate an alternative embodiment.

In these figures, parts and elements identical or functionally similar to parts and elements already described have been again attributed the same reference numbers used previously.

The variant according to figures 3 and 4 differs from the embodiment according to figures 1 and 2 essentially in that the periphery of the obturator 17 is made integral with an elastically flexible and extensible tubular bellows 16 and with the annular gasket 3 locked between the elements 2a and 2b of the body 2 of the electric valve device. In other words, the gasket 3, the bellows 16 and the obturator 17 are appropriately formed as a single element of a suitable material, for example elastomeric material. Such elastomeric material element allows permanently protecting the helical spring 19 and the member 12 from the flowing fluid, with the electric valve device 1 open, between the conduits 4 and 5.

Figures 5 to 7 illustrate a further variant of embodiment.

Also in these figures, parts and elements identical or functionally similar to parts and elements already described have been attributed the same reference numbers used previously.

In the variant according to figures 5 to 7, the obturators 17 and 18, respectively associated with the valve seats 7 and 8, are integrated in a single annular element 20 of elastomeric material. Such element 20 comprises in particular an elastically flexible and extensible intermediate portion 21 that interconnects between the obturators 17 and 18 (see in particular figure 6).

In addition, in the obturator assembly 13, the lower body 15 is mounted in an axially moveable manner relative to the upper body 14, and a helical spring 22 is interposed therebetween and tends to propel the body 15 away and downward, relative to the body 14.

This solution allows ensuring adequate sealing between the obturator 18 and the associated valve seat 8 also in the case wherein, by the effect of pinching granules between the obturator 17 and the associated valve seat 7, the obturator assembly 13 should be slightly raised with respect to the nominal closed position.

To better support the lower portion of the elastomeric element 20 or the obturator 18, the body 15 is made with a terminal head 15a and an overlying formation 15b, protruding radially outward in the manner of a flange, and the obturator 18 is inserted in the groove defined therebetween.

For the rest, in the embodiment according to figures 5 to 7, the electric valve device 1 operates substantially as in the embodiments described in relation to the previous figures. Figure 8 illustrates a further variant of embodiment.

Also in this figure, parts and elements identical or functionally similar to parts and elements already described have been attributed the same reference numbers used previously.

The variant of figure 8 corresponds to the variant of figures 5 to 7 in that the obturators 17 and 18, respectively associated with the valve seats 7 and 8, are integrated in a single annular element 20 of an elastomeric material and corresponding to the variant of figures 3-4 in that that the periphery of the obturator 17 is integrated with an elastically flexible and extensible tubular bellows 16 and with the annular gasket 3, locked between the elements 2a and 2b of the body 2 of the electric valve device. In this variant, therefore, the element 20 is constituted of a single body of elastomeric material, which integrates the obturator 17 and 18, the intermediate portion 21 that interconnects them, the gasket 3 and the bellows 16 that connects the gasket 3 to the obturators.

For the rest, in the embodiment according to figure 8, the electric valve device 1 operates substantially as in the embodiments described in relation to the previous figures.

According to embodiments which provide for deformability of the second obturator 17 and/or the helical spring 22 interposed between the lower body 15 and the upper body 14 of the obturator group 13, it is possible to configure the first obturator 17 and the second obturator 18 such that the first obturator 17 closes and/or opens the associated first valve seat 7 and the second obturator 18 respectively closes and/or opens the associated second valve seat (8) in a manner temporally staggered one with respect to the other.

Such configuration allows, with a repeated activation of the closing valve, a "self-cleaning" effect of the valve seat 7 or 8 to be achieved, through the removal of any particles which become lodged on the valve seat and compromise its seal.

Furthermore, in the versions with integrated gasket and/or obturator of figures 3 through 8, such configuration allows a "pumping" function to dislodge any residues from the seats and remove them by activating the valve in a repeated way. This type of activation allows for example for the closure of first the second seat 8 and then the first seat 7 to be achieved, pushing away the water and any impurities present in the volume between the two seats; a subsequent opening will then open first the second seat 8 then the first seat 7, generating a "piston pump" effect that allows any dirt from the seats to be removed.

Naturally, without altering the principle of the invention, the embodiments and the details of construction may vary widely with respect to those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the appended claims.