The present invention relates to a device for detecting the level of a liquid in a container, particularly a device for detecting the level of the washing bath in a washing machine such as a laundry washing machine or a dishwasher.
More specifically, the invention relates to a detector device comprising:
A known device of this type for laundry washing machines is located outside the washing bath with the opening of the aforesaid first chamber connected through a pipe, which is generally flexible, to an “air trap” mounted in the washing bath in the vicinity of the level of the washing bath which is to be detected. The “air trap” can be simply a kind of cup in an inverted position with a top opening connected to the level detector device through the aforesaid flexible pipe.
The known solution described above has a number of drawbacks. In the first place, it requires the use of the detector device and the air trap and their interconnection by means of a flexible pipe, typically using hose clamps.
One object of the present invention is to provide an improved device for detecting the level of a liquid in a container by means of which the level of the liquid can be detected directly, without using an “air trap” and without connecting pipes.
This and other objects are achieved according to the invention with a detector device of the type defined above, the principal feature of which resides essentially in the fact that the aforesaid resilient means are located in the aforesaid second chamber.
The detector device according to the invention can be mounted directly in the washing bath of a washing machine, in such a way that the inlet opening or mouth of its aforesaid first chamber faces the liquid (the washing bath) in operation, and can be closed by the liquid when the level of the latter rises above a predetermined level, such that the first chamber then acts as an air trap.
The aforesaid second resilient means, which can be made, for example, in the form of a spiral spring, are protected from direct contact with the washing bath and from any foreign bodies contained therein, such as lint or other residues.
Further features and advantages of the invention will be made clear by the following detailed description, provided purely by way of non-limiting example, with reference to the appended drawings, in which:
a is a partial perspective view of the spool member; and
In
In the embodiment illustrated by way of example, the device 1 comprises an essentially cylindrical tubular body 2, made for example from moulded plastic material.
The body 2 is closed at its top by a cover 3, which is preferably removable.
In its lower part, the body 2 is provided internally with a collar-like annular formation 4, which has an essentially L-shaped cross section. An annular channel 5, open at its top, is formed between the essentially vertical branch of this formation and the wall of the body 2.
The number 6 indicates a diaphragm, made for example from elastomeric material.
This diaphragm has a peripheral ring 6a, fitted in the channel 5 of the body 2. The ring 6a is joined to an intermediate annular portion 6b of the diaphragm 6, which is highly flexible, and which is joined in turn to a central portion 6c of said diaphragm, which is essentially thicker and therefore relatively more rigid. A recess or indentation 6d is formed in the central part of the upper surface or face of the diaphragm 6.
The number 7 in
The member 7 has a lower portion 7b, which is essentially bell-shaped and has a larger diameter. This bell-shaped portion 7b has a circumferential projection 7c, beveled or rounded towards its lower part and towards the axis.
Immediately below this projection, the portion 7b of the spool member 7 has a plurality of essentially radial through holes 7d.
The member 7 is inserted into the body 2 through the upper end of the latter, and is therefore mounted in the position shown in
In the assembled condition shown in
The holes 2a in the body 2 communicate at least partially with the holes 7d of the spool member 7, for reasons which are explained below.
The spool member 7 is axially traversed by a passage 9 which is open below and which is closed at its top by a transverse partition 10 integral with the member 7. This passage 9 extends downwards to the end of a tubular appendage 7e of the member 7, which extends downwards to a certain distance from the diaphragm 6.
The number 11 indicates a movable core, made from ferromagnetic material for example, mounted in the passage 9 of the body 7.
In the illustrated embodiment, the core 11 has a lower shank 11a engaged in the central indentation or recess 6d of the diaphragm 6, and a tapered upper protuberance 11b.
A helical spring 12 is positioned in the passage 9 of the member 7, between the upper end of the core 11 and the partition 10. This spring tends to push the core 11 towards the diaphragm 6.
The diaphragm 6 divides the inner region enclosed by the body 2 and by the lower portion 7b of the spool member 7 into two chambers 14 and 15 which are sealingly separated from each other.
The chamber 14 opens downwards at the position of the wide mouth 2c of the lower end of the tubular body 2.
The chamber 15 is in permanent communication with the atmosphere surrounding the device 1, via the holes 7d of the spool member 7 and the holes 2a of the body 2.
The number 16 indicates a further spring which is of the spiral type in the illustrated embodiment. This spring is positioned in the chamber 15, and is therefore located between the diaphragm 6 and the spool member 7, and in particular it surrounds the tubular appendage 7e of the latter.
At rest, the spring 16 is essentially flat, as shown in
The arrangement is such that the spring 12 pushes the core 11 downwards, in such a way that the lower end of the core deforms the flat spring 16, making it assume the configuration shown in
The periphery of the spring 16 is fastened to the lower portion 7b of the spool member 7 as described below.
With reference to
As shown in
The protuberances 20 have cross sections which are essentially complementary to those of the larger cut-outs 18 of the spiral spring 16.
As shown more fully in
Accordingly, the fitting of the spring 16 into the lower portion 7b of the spool member takes place essentially in the following manner.
The spring 16 is inserted through the lower hole of said portion 7b of the spool member 7, with the larger cut-outs 18 sliding in a guided way along the corresponding protuberances 20. The translation of the spring 16 continues until its periphery is carried beyond the top of the projections 21 of the holes 7d, as shown in
The procedure for coupling and mounting the spring 16 on the spool member 7 is essentially what is known as a bayonet coupling procedure.
With reference to
The detector device 1 described above is suitable for use in the washing bath of a washing machine, particularly a laundry washing machine, in such a way that its lower opening or mouth 2c can be closed by the body of washing liquid contained in this bath when its level rises above a predetermined reference level. In this condition, the chamber 14 of the device 1 acts in exactly the same way as an air trap. The air trapped in the chamber 14 is pressurized by the tendency of the washing bath to rise further. The increase in pneumatic pressure in the chamber 14 causes the upward displacement of the diaphragm 6, and consequently the core 11, with respect to the winding 8. The inductance of this winding varies accordingly, and this variation can be detected, for example in the form of a variation of the frequency of an LC resonant circuit.
The direct exposure of the level detector device 1 to the washing bath is made possible, in particular, by the fact that the spring 16 is housed safely in the chamber 15 which is sealingly separated from the chamber 14 into which said washing liquid or bath can penetrate.
If a loss of sealing between the chambers 14 and 15 occurs after prolonged operation, for example as a result of a tear in the diaphragm 6, any liquid entering the chamber 15 can be removed through the holes 7d of the spool member 7 and the corresponding holes 2a of the body 2 of the device.
Naturally, the principle of the invention remaining the same, the forms of embodiment and the details of construction may be varied widely with respect to those described and illustrated, which have been given purely by way of non-limiting example, without thereby departing from the scope of the invention as defined by the attached claims.
Number | Date | Country | Kind |
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TO2008A000796 | Oct 2008 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB09/54722 | 10/26/2009 | WO | 00 | 4/27/2011 |