DETECTOR DEVICE FOR DETECTING LIQUID SUCKED FROM A CONTAINER

Abstract

Detector device configured to detect presence of liquid in a container comprising a main duct (100) provided with an inlet (115), configured to be connected to a container, and with an outlet (125), configured to be connected to a suction device, wherein the main duct (100) is in communication with a detection chamber (200) through a branch channel (130, 210) and a return channel (140, 220), the detection chamber (200) being closed by a top cap (240) and by a bottom wall (235) and comprising a stem (250) that is coupled to at least one between the top cap (240) and the bottom wall (235) and that internally houses a reed switch (260), wherein the stem (250) is inserted into a longitudinal cavity (283) of afloat (280A; 280B) housing at least one permanent magnet (285) in an inner seat, the float (280A; 280B) being configured to slide along the stem (250) between a rest position and a floating position, wherein: one between the rest position and the floating position coincides with a position of interaction of the float (280A; 280B) with the reed switch (260), at which said at least one permanent magnet (285) magnetically interacts with the reed switch (260), whereby the reed switch (260) is closed; and the other one between the rest position and the floating position coincides with a position of non-interaction of the float (280A; 280B) with the reed switch (260), at which said at least one permanent magnet (285) does not magnetically interact with the reed switch (260), whereby the reed switch (260) is open.

Claims

1. Detector device configured to detect presence of liquid in a container, comprising a main duct provided at a first end with an inlet, configured to be connected to the container, and at a second end with an outlet, configured to be connected to a suction device, wherein an inner channel of the main duct is in communication with a detection chamber through a branch channel and a return channel arranged along a lateral surface of the main duct extending between the first and the second end, wherein the branch channel is arranged between the first end of the main duct and the return channel and wherein the return channel is arranged between the second end of the main duct and the branch channel, the detection chamber being closed by a top cap and by a bottom wall and comprising a stem that is coupled to at least one between the top cap and the bottom wall and that internally houses a reed switch, wherein the stem is inserted into a longitudinal cavity of a float housing at least one permanent magnet in an inner seat, the float being configured to slide along the stem between a rest position and a floating position, wherein: one between the rest position and the floating position coincides with a position of interaction of the float with the reed switch, at which said at least one permanent magnet magnetically interacts with the reed switch, whereby the reed switch is closed; and the other one between the rest position and the floating position coincides with a position of non-interaction of the float with the reed switch, at which said at least one permanent magnet does not magnetically interact with the reed switch, whereby the reed switch is open.

2. Detector device according to claim 1, wherein an area of a section of the return channel is less than an area of a section of the branch channel.

3. Detector device according to claim 1, wherein said inner channel of the main duct comprises an end portion, extending from the first end to the branch channel, that has an inner volume at least equal to 50% of an inner volume of the detection chamber extending from the bottom wall to the return channel.

4. Detector device according to claim 1, wherein the rest position coincides with the position of interaction of the float with the reed switch and the floating position coincides with the position of non-interaction of the float with the reed switch.

5. Detector device according to claim 1, wherein the stem is coupled only to the top cap, whereby the stem protrudes from the top cap, wherein wires connected to terminals of two magnetically actuated ferromagnetic reeds of the reed switch are housed within a cable exiting from the cap.

6. Detector device according to claim 5, wherein a free end of the stem, that is facing the bottom wall, is provided with a rest position stop bolt configured to prevent the float from sliding beyond said free end.

7. Detector device according to claim 1, wherein the top cap is removably coupled to the detection chamber and the bottom wall is integrally coupled to the detection chamber.

8. Detector device according to claim 7, wherein the top cap is provided with a threaded rim screwed internally to an end of the detection chamber, a first OR-ring seal ensuring sealing between the detection chamber and the top cap.

9. Detector device according to claim 1, wherein the main duct is provided with a branch mouth and a return mouth respectively coupled to a branch duct and a return duct with which the detection chamber is provided, wherein the branch channel is formed by the branch mouth and the branch duct, and wherein the return channel is formed by the return mouth and the return duct.

10. Detector device according to claim 9, wherein the branch duct is inserted into the branch mouth with a sealing coupling and wherein the return duct is inserted into the return mouth with a sealing coupling.

11. Detector device according to claim 1, wherein the inlet is provided with a threaded rim screwed internally to the first end of the main duct, a second O-ring seal ensuring sealing between the main duct and the inlet, whereby the inlet is removably coupled to the first end of the main duct, and wherein the outlet is provided with a threaded rim screwed internally to the second end of the main duct, a third O-ring seal ensuring sealing between the main duct and the outlet, whereby the outlet is removably coupled to the second end of the main duct, wherein the inlet is provided with an inlet duct through which it is configured to be connected to the container, and wherein the outlet is provided with an outlet duct through which it is configured to be connected to the suction device.

12. Detector device according to claim 1, wherein the stem has a cylindrical or prism shape.

13. Detector device according to claim 1, wherein the longitudinal cavity of the float has a shape corresponding to the one of the stem.

14. Detector device according to claim 2, wherein the area of said section of the return channel ranges from 20% to 60% of the area of said section of the branch channel.

15. Detector device according to claim 2, wherein the area of said section of the return channel ranges from 25% to 50% of the area of said section of the branch channel.

16. Detector device according to claim 2, wherein the area of said section of the return channel ranges from 30% to 40% of the area of said section of the branch channel.

17. Detector device according to claim 2, wherein the area of said section of the return channel is equal to about 35% of the area of said section of the branch channel.

18. Detector device according to claim 1, wherein said inner channel of the main duct comprises an end portion, extending from the first end to the branch channel, that has an inner volume at least equal to 75% of an inner volume of the detection chamber extending from the bottom wall to the return channel.

19. Detector device according to claim 9, wherein the branch duct is inserted into the branch mouth with a plug-in coupling and wherein the return duct is inserted into the return mouth with a plug-in coupling.

Description

[0041] The present invention will be now described, by way of illustration and not by way of limitation, according to its preferred embodiments, by particularly referring to the Figures of the annexed drawings, in which:

[0042] FIG. 1 shows a perspective view (FIG. 1a) and a front view (FIG. 1b) of a first embodiment of the detector device according to the invention;

[0043] FIG. 2 shows a longitudinal section view of the detector device of FIG. 1;

[0044] FIG. 3 shows an exploded perspective view of the detector device of FIG. 1;

[0045] FIG. 4 shows two longitudinal partial section views of the detector device of FIG. 1, in one of which the float is in a rest position (FIG. 4a), while in the other one the float is in a floating position;

[0046] FIG. 5 shows a longitudinal section view of the portion of the detector device of FIG. 1 containing the detection chamber wherein the float is in the rest position (FIG. 5a) and in the detecting position (FIG. 5b); and

[0047] FIG. 6 shows a longitudinal section view of the portion of a second embodiment of the detector device according to the invention containing the detection chamber wherein the float is in the rest position (FIG. 6a) and in the detecting position (FIG. 6b).

[0048] In the Figures identical reference numerals will be used for alike elements.

[0049] With reference to FIGS. 1-4, it may be observed that a first embodiment of the detector device according to the invention comprises a main duct 100, with substantially cylindrical shape, having a longitudinal axis z, that is provided at a first end 110 with a removable inlet 115 configured to be connected to a container and at a second end 120 with a removable outlet 125 configured to be connected to a suction pump (or to a different suction device, such as for instance an external venturi dosingor mixerdevice). The inlet 115 is provided with a threaded rim 116 that screws internally to the first end 110 (that has a corresponding threaded portion) and with an inlet duct 117 (configured to be connected to a container directly or through a first intermediate duct), while a conventional OR-ring seal 118 ensures sealing between the main duct 100 and the inlet 115; similarly, the outlet 125 is provided with a threaded rim 126 that screws internally to the second end 120 (that has a corresponding threaded portion) and with an outlet duct 127 (configured to be connected to a suction pump directly or through a second intermediate duct), while a conventional OR-ring seal 128 ensures sealing between the main duct 100 and the outlet 125.

[0050] The detector device according to the invention has an operating configuration wherein the second end 120 and the outlet 125 are at an height above the ground (namely, above the ground on which the container to which the detector device is applied rests) higher than the height above the ground at which the first end 110 and the inlet 115 are, wherein optionally the longitudinal axis z of the main duct 100 extends along a vertical orientation; in the Figures, the detector device according to the invention is shown in its operating configuration. In particular, when the detector device according to the invention assumes the operating configuration, a liquid contained in the main duct 100 that is subject to gravity alone exits from the inlet 115 (and not from the outlet 125, from which differently air enter the main duct 100).

[0051] The main duct 100 is also provided with a branch mouth 130 and a return mouth 140, arranged along the lateral surface of the main duct 100; the branch mouth 130 is arranged between the first end 110 (or the inlet 115) and the return mouth 140, while the return mouth 140 is arranged between the branch mouth 130 and the second end 120 (or the outlet 125).

[0052] The detector device according to the invention further comprises a detection chamber 200, with substantially cylindrical shape, having a longitudinal axis (not shown in the Figures) parallel to the longitudinal axis z of the main duct 100. The detection chamber 200 has a branch duct 210 and a return duct 220, arranged on the lateral surface of the same detection chamber 200, which are, optionally removably, connected to the branch mouth 130 and return mouth 140, respectively. When connected to each other, the branch duct 210 and the branch mouth 130 form a branch channel, while the return duct 220 and the return mouth 140 form a return channel which put the inner channel of the main duct 100 in communication with the inside of the detection chamber 200. In particular, in the first embodiment shown in FIGS. 1-5, the branch duct 210 is inserted into the branch mouth 130 with a sealing coupling (e.g. through conventional seals), optionally a plug-in coupling, and the return duct 220 is inserted into the return mouth 140 with a sealing coupling (e.g. through conventional seals), optionally a plug-in coupling. Optionally, the area of the section of the return channel (i.e., the area of the section orthogonal to the return channel axis and internal to the walls delimiting the return channel) is lower than the area of the section of the branch channel (i.e., the area of the section orthogonal to the branch channel axis and internal to the walls delimiting the branch channel); more optionally, the area of the section of the return channel ranges from 20% to 60%, still more optionally from 25% to 50%, even more optionally from 30% to 40%, even still more optionally equal to about 35% of the area of the section of the branch channel.

[0053] When the detector device assumes the operating configuration, the return duct 220 and the return mouth 140 are at a height above the ground (namely above the ground on which the container to which the detector device is applied rests) higher than the height above the ground at which the branch duct 210 and the branch mouth 130 are.

[0054] The detection chamber 200 is provided at its return end 230 with a removable top cap 240 having a stem 250, that is substantially cylindrical (even if the shape of the stem is not an essential feature for the invention, and it could also be a prism with any polygonal bases, e.g. squares, rectangles, parallelograms, rhombuses, pentagons, hexagons and the like), that protrudes from the top cap 240 and that internally houses a reed switch 260, the wires 265 of which (connected to the terminals 267 of the two magnetically actuated ferromagnetic reeds) are housed in a cable 270 exiting from the removable top cap 240; in particular, the housing of the reed switch 260 inside the stem 250 is sealed, whereby liquid possibly present in the detection chamber 200 may not enter the housing and come into contact with the reed switch 260. By way of example and not by way of limitation, the top cap 240 is provided with a threaded rim 245 that screws internally to the end 230 (that has a corresponding threaded portion), and a conventional OR-ring seal 248 may be used to ensure sealing between the detection chamber 200 and the top cap 240. A branch end, opposite to the return end 230, is closed by a bottom wall 235, opposite to the top cap 240, integrally coupled to the lateral (substantially cylindrical) wall of the detection chamber 200.

[0055] The stem 250 is inserted into the longitudinal cavity 283 of a float 280A, having substantially shape of a hollow cylinder and advantageously made of plastic material (or in any case of a material compatible with the liquid flowing through the main duct 100 and entering the detection chamber 200, in the manner that will be described later). The float 280A houses in an inner seat (at least) one permanent magnet 285 (shown in FIGS. 2, 4 and 5) and is configured to slide along the stem 250 between a rest position shown in FIG. 4a (as well as in FIGS. 2 and 5a), at which said (at least) one permanent magnet 285 magnetically interacts with and consequently closes the reed switch 260, and a floating position shown in FIG. 4b (as well as in FIG. 5b), at which said (at least) one permanent magnet 285 does not magnetically interact with the reed switch 260 that remains open. Advantageously, the longitudinal cavity 283 has shape corresponding to the one of the stem, whereby (in the embodiment of the detector device of FIGS. 1-5) it is substantially cylindrical (even if the shape of the longitudinal cavity, as for the stem, is not an essential feature for the invention, and it could also be a prism with any polygonal bases, e.g. squares, rectangles, parallelograms, rhombuses, pentagons, hexagons and the like). The free end of the stem 250 (that is facing the bottom wall 235) is provided with a threaded portion 255 that is configured to removably screws into a rest position stop bolt 290 that, consequently, couples to the free end of the stem 250 and prevents the float 280A from sliding below such free end and disengaging from the stem 250.

[0056] As stated above, the float 280A houses in an inner seat (at least) one permanent magnet 285 configured to magnetically interact with the reed switch 260 (namely, with the ferromagnetic reeds thereof) housed in the stem 250, as it will be described in greater detail later. The inner seat housing the permanent magnet 285 is sealed, whereby liquid possibly present in the detection chamber 200 may not enter in the inner seat and come into contact with the permanent magnet 285. In the first embodiment of the detector device according to the invention, the permanent magnet 285 is in a position of the inner seat closer to a first end 281 of the float 280A (which first end 281 is facing the inner wall of the top cap 240) than the other end 282 of the float 280A (which other end 282 is facing the bottom wall 235), whereby the permanent magnet 285 is positioned in proximity of the first end 281 of the float 280A, and it is optionally stably kept in such position by (at least) one cylindrical insert 286 housed in the inner seat of the float 280A as well.

[0057] It should be noted that other embodiments of the detector device according to the invention may have different couplings among the several elements, still remaining within the scope of protection of the present invention defined by the attached claims.

[0058] For instance, other embodiments of the detector device according to the invention may have the inlet 115 and/or the outlet 125 which have an internal thread into which a threaded rim of the first end 110 and/or the second end 120, respectively, of the main duct 100 screws; alternatively the inlet 115 and the first end 110 of the main duct 100 and/or the outlet 125 and the second end 120 of the main duct 100 may be configured to be coupled to each other through a plug-in coupling.

[0059] Further embodiments of the detector device according to the invention may have the inlet 115 and/or the outlet 125 that, instead of being removable, are integrally coupled to the first end 110 and/or the second end 120, respectively, of the main duct 100.

[0060] Also, other embodiments of the detector device according to the invention may have the branch mouth 130 that is inserted into the branch duct 210 with a sealing coupling (e.g. through conventional seals), and possibly even the return mouth 140 may be inserted into the return duct 220 with a sealing coupling (e.g. through conventional seals).

[0061] Moreover, further embodiments of the detector device according to the invention may have the top cap 240 that has an internal thread into which a threaded rim of the end 230 of the detection chamber 200 screws, or the top cap 240 and the end 230 of the detection chamber 200 are configured to be coupled to each other through a plug-in coupling.

[0062] Furthermore, other embodiments of the detector device according to the invention may have the top cap 240 that, instead of being removable, is integrally coupled to the detection chamber 200 and/or the bottom wall 235 that, instead of being integrally coupled, is removably coupled to the (lateral wall of the) detection chamber 200 with a sealing coupling (e.g., thanks to a conventional OR-ring seal).

[0063] Also, further embodiments of the detector device according to the invention may have the stem 250 that is removably coupled to the top cap 240 (e.g. through a threaded or plug-in coupling) and/or the rest position stop bolt 290 and the free end of the stem 250 are configured to be coupled to each other through a plug-in coupling or the rest position stop bolt 290 is integrally coupled to the free end of the stem 250.

[0064] Moreover, other embodiments of the detector device according to the invention may be devoid of the rest position stop bolt; in this case, the free end of the stem 250 is spaced apart from the bottom wall 235 of the detection chamber 200 by a distance shorter than the longitudinal extension of the float 280A, optionally by a distance not longer than 75%, more optionally not longer than 50%, still more optionally not longer than 25% of the longitudinal extension of the float 280A.

[0065] Furthermore, other embodiments of the detector device according to the invention may have the stem 250 that is provided with a floating position stop bolt or other floating position stop element arranged in proximity of the end of the stem 250 coupled to the top cap 240, that prevents the float 280A from sliding over such end and coming into contact with the inner wall of the top cap 240. In this case, the stem 250 may be provided with the rest position stop bolt or not.

[0066] Furthermore, other embodiments of the detector device according to the invention may have the stem 250 that, instead of being coupled to the top cap 240, is coupled to the bottom wall 235 and protrudes from the bottom wall 235 (and still internally houses a reed switch 260, the wires 265 of which are housed in a cable 270 exiting from the bottom wall 235); in this case, the free end of the stem 250 (that is facing the inner wall of the top cap 240) may be provided with a, optionally removable, stop bolt that prevents the float 280A from sliding over such free end and disengaging from the stem 250 (however, it should be noted that even in this arrangement with stem 250 protruding from the bottom wall 235 the stop bolt is not an essential feature for the invention). Alternatively, the stem 250 may be coupled to both the top cap 240 and the bottom wall 235; in this case, the stem 250 may be integrally coupled to both (advantageously, the detection chamber and the float will be made in twoor even morepieces which are for instance fused to each other during the manufacturing process), or the stem 250 may be integrally coupled to only one between the top cap 240 and the bottom wall 235 while it is removably coupled to the other one between the top cap 240 and the bottom wall 235, or the stem 250 may be removably coupled to both the top cap 240 and the bottom wall 235. Even in the just described arrangements, the stem 250 may be provided with a rest position stop bolt (preventing the float 280A from sliding below a rest position) and/or with a floating position stop bolt (preventing the float 280A from sliding over a floating position).

[0067] Consequently, in general, the stem 250 is coupled to at least one between the top cap 240 and the bottom wall 235 and its wires 265 are housed in a cable 270 exiting from one between the removable top cap 240 and the bottom wall 235 to which the stem 250 is coupled; the latter is optionally provided with a rest position stop bolt and/or with a floating position stop bolt.

[0068] Moreover, other embodiments of the detector device according to the invention may have said (at least) one permanent magnet 285 housed in the inner seat of the float 280A in a position different from the one shown in FIGS. 2, 4 and 5, for instance in a central position, provided that said (at least) one permanent magnet is configured to magnetically interact with the reed switch 260 (namely, with the ferromagnetic reeds thereof) housed in the stem 250, as it will be described in greater detail later. By way of example, the shape and size of the float 280A and/or the shape and size of the inner seat in which said (at least) one permanent magnet is housed and/or the position of said (at least) one permanent magnet in the inner seat of the float and/or the shape and size of the stem 250 housing the reed switch 260 and/or the position of the reed switch 260 in the stem 250 are adapted to allow said (at least) one permanent magnet to magnetically interact with the reed switch 260, as it will be describer in greater detail later.

[0069] In order to better understand the detector device according to the invention, the operating modes of the first embodiment shown in FIGS. 1-5 are described in the following, similar modes being valid also for the other embodiments.

[0070] The detector device according to the invention is inserted between a container (having either a rigid structure, as a tank, or a non-rigid one, as a bag) containing a liquid (e.g. a liquid chemical product) and an external suction pump (e.g., a dosing pump). In particular, the detector device must assume the operating configuration, the inlet 115 is connected (directly or through a first intermediate duct) to the container and the outlet 125 is connected to the external suction pump, whereby the detector device allows the pump to suck the liquid that is inside the container and the liquid sucked by the pump flows through the same detector device.

[0071] The detector device according to the invention is based on the interaction of the magnetic field generated by the permanent magnet 285 housed in the inner seat of the float 280A and the reed switch 260 housed in the stem 250.

[0072] As shown in FIGS. 2, 4a and 5a, when no liquid is present in the detection chamber 200, the float 280A is configured to fall onto the rest position stop bolt 290 due to the force of gravity and thus to stably stay in the rest position even if the suction pump connected downstream of the outlet 125 is operated to suck. Consequently, the permanent magnet 285 is in the rest position at which it magnetically interacts with (i.e. excites) the reed switch 260 and causes the same reed switch 260 to close. Therefore, the permanent magnet 285 assumes the rest position when either the external pump is off or the external pump does not suck any liquid, for instance because the container has not a liquid amount sufficient to allow the external pump to suck the same liquid (in particular, as it occurs when the container is empty).

[0073] Differently, as shown in FIG. 5b, when the external suction pump succeeds in sucking liquid from the container, the liquid flows through the main duct 100 and simultaneously (at least partially) fills the detection chamber 200 (through the branch channel formed by the branch mouth 130 and the branch duct 210), whereby the float 280A floats in the liquid 300 present in the detection chamber 200 and, consequently, slides from the rest position up to reaching and stably maintaining the floating position at which the permanent magnet 285 does not magnetically interact any more with (i.e. de-excites) the reed switch 260 (since the permanent magnet 285 is far away from the reed switch 260), that thus opens (i.e. interrupts the contact between its own ferromagnetic reeds); optionally, in the floating position the float 280A comes into contact with the inner wall of the removable top cap 240. In particular, the liquid in the detection chamber 200 is preferably sucked by the branch channel (formed by the branch mouth 130 and the branch duct 210) rather than from the return channel (formed by the return mouth 140 and the return duct 220), especially when the area of the section of the return channel is lower than the area of the section of the branch channel.

[0074] If during suction the container gets empty (i.e. the liquid is absent or in any case the liquid amount is insufficient to allow the external pump to suck the same liquid), the detection chamber 200 gets empty as well and the float 280 descends from the floating position down to the rest position detecting the absence of the liquid thanks to the closing of the reed switch 260, short-circuiting the wires 265 (connected to the terminals 267 of the two magnetically actuated ferromagnetic reeds) and thus signalling the absence of liquid in the container.

[0075] Differently, when suction is stopped and liquid is still present in the container (that hence is not empty), in the first embodiment of the detector device according to the invention shown in FIGS. 1-5 (and also in other embodiments), generally liquid remains in the detection chamber 200 and the float 280 remains in the floating position. In other words, in the first embodiment of the detector device (and also in other embodiments), the detection chamber 200 gets empty only when the container is empty and the external suction pump (or another suction device) is sucking. In fact, when liquid flows through the main duct 100, liquid fills the detection chamber 200 as well by means of suction and on the basis of the principle of communicating vessels; instead, when there is no liquid flow through the main duct 100, i.e. when suction from the outlet 125 is stopped, but the container is not empty, liquid that has previously filled the detection chamber 200 stagnates in the latter.

[0076] Differently, in different embodiments of the detector device according to the invention, in absence of suction, liquid could flow back towards the container and the detection chamber 200 could get empty even when suction is stopped, whereby in this case the float 280 descends from the floating position down to the rest position.

[0077] Optionally, in order to more effectively empty the detection chamber 200, the inner channel of the main duct 100 comprises an end portion 105, extending from the first end 110 to the aperture of the branch mouth 130, that has an inner volume at least equal to 50%, more optionally at least equal to 75%, of the inner volume of the detection chamber 200 extending from the bottom wall 235 to the aperture of the return duct 220. Alternatively, at least part of the end portion 105 may be replaced with a first intermediate duct, having adequate size, connecting the inlet 115 to the container.

[0078] Advantageously, in the embodiments of the detector device wherein the area of the section of the return channel is lower than the area of the section of the branch channel, formation of air bubbles is avoided while the detection chamber 200 is emptied.

[0079] Also, in the embodiments having an adequate area of the section of the branch channel, the detector device according to the invention operates correctly even with very viscous liquids.

[0080] The suction pumps, in particular pumps dosing liquid chemical products, in common applications are installed on the wall. As illustrated, the detector device is installed upstream of the external suction pump, whereby it is installed below the suction pump with the longitudinal axis z of the main duct 100 extending along a vertical orientation, and consequently it certainly assumes the operating configuration.

[0081] However, the detector device is capable to operate correctly even if it is installed so that the longitudinal axis z of the main duct 100 extends with an orientation inclined with respect to a straight line perpendicular to ground (i.e. a vertical straight line), provided that the float 280A can descend from the floating position down to the rest position due to gravity and that the liquid can return through the branch channel from the detection chamber 200 to the main duct 100 and possibly in the container to which the inlet 115 is connected. By way of example and not by way of limitation, the detector device could operate even when inclined by 45.

[0082] A second embodiment of the detector device according to the invention is different from the one shown in FIGS. 1-5 only for the features of the float. As shown in FIG. 6, even in such second embodiment of the detector device, the float 280B houses in an inner seat (at least) one permanent magnet 285 configured to magnetically interact with the reed switch 260 (namely, with the ferromagnetic reeds thereof) housed within the stem 250. In the float 280B, the permanent magnet 285 is in a position of the inner seat closer to the other end 282 of the float 280B (which other end 282 is facing the bottom wall 235) than the first end 281 of the float 280B (which first end 281 is facing the inner wall of the top cap 240), whereby the permanent magnet 285 is positioned in proximity of the other end 282 of the float 280B, and it is optionally stably maintained in such position by (at least) one cylindrical insert 286 housed within the inner seat of the float 280B as well.

[0083] In the detector device of FIG. 6 the operating logic of the reed switch 260 is inverted. In fact, as shown in FIG. 6a, when no liquid is present in the detection chamber 200, the float 280B is configured to fall onto rest position stop bolt 290 due to the force of gravity and thus to stably stay in the rest position even if the suction pump connected downstream of the outlet 125 is operated to suck. Consequently, the permanent magnet 285 is in the rest position at which it does not magnetically interact with (i.e. de-excites) the reed switch 260 (since the permanent magnet 285 is far away from the reed switch 260), that is thus open (i.e. it interrupts the contact between its own ferromagnetic reeds). Differently, as shown in FIG. 6b, when the external suction pump succeeds in sucking liquid from the container, liquid flows through the main duct 100 and simultaneously (at least partially) fills the detection chamber 200 (through the branch channel formed by the branch mouth 130 and the branch duct 210), whereby the float 280B floats in the liquid 300 present in the detection chamber 200 and, consequently, slides from the rest position up to reaching and stably maintaining the floating position, at which the permanent magnet 285 magnetically interacts with (i.e. excites) the reed switch 260 and causes the same reed switch 260 to close; advantageously, in the floating position the float 280B comes into contact with the inner wall of the removable top cap 240.

[0084] It should be noted that even the first embodiment of the detector device shown in FIGS. 1-5 may be caused to operate with the same operating logic of the reed switch 260 shown in FIG. 6. In fact, it is sufficient to mount the float 280A on the stem 250 with reverse orientation with respect to what shown in FIGS. 1-5, i.e. with the first end 281 of the float 280A facing the bottom wall 235 and with the other end 282 of the float 280A facing the inner wall of the top cap 240, thus obtaining an arrangement of the magnet 285 with respect to the reed switch 260 similar to what shown in FIG. 6.

[0085] Alternatively, most of all in the case where the area of the section of the return channel and the area of the section of the branch channel are equal or substantially comparable to each other (e.g. they do not differ from each other by more than 25%), it is possible to mount the detector device shown in FIGS. 1-5 upside down, i.e. with the outlet 125 (operating as inlet) connected to the container and the inlet 115 (operating as outlet) connected to the suction pump to invert the operating logic of the reed switch 260 of the detector device.

[0086] The preferred embodiments of this invention have been described and a number of variations have been suggested hereinbefore, but it should be understood that those skilled in the art can make other variations and changes without so departing from the scope of protection thereof, as defined by the attached claims.