RELIABILITY OF AN OVERFLOW MECHANISM

DESCRIPTION

Field of the invention

The present invention concerns an assembly comprising a drain for sanitary fixtures, in particular a drain provided with an overflow mechanism with automatic reloading mechanism, and an aerator, and a method for achieving the proper aeration of the drain during its operation.

State of the art

In the industry of sanitary fixtures, it is known to make sinks, washbasins and tubs which, for aesthetic reasons, are devoid of the overflow hole, i.e. are not provided with the hole for draining excess water, a hole which, in most sanitary fixtures, is obtained in the side wall to prevent the level of water contained in the sanitary fixture from exceeding a maximum value and overflowing outside.

EP-A-2281955, in the name of the Applicant, describes a drain comprising a cylindrical body having a bottom grid at the base and, at its top, an annular rosette delimiting the mouth for the passage of water through the drain body. A plug is housed in the drain body and is axially movable between a lowered position, wherein the head of the plug is under the rosette and does not intercept the opening of the mouth, thus allowing the passage of water, and a raised position, wherein the head of the plug intercepts the rosette and prevents the passage of water through the mouth.

The plug leans on the bottom grid of the drain body by means of a helical spring which is calibrated so that to yield at the exceeding of a predetermined pressure value: when the water volume contained in the sanitary fixture reaches and exceeds a maximum value, at the maximum tolerable level of water, the pressure acting on the plug exceeds the predetermined value and overcomes the resistance provided by the helical spring, which yields, thus causing the lowering of the plug and, therefore, the draining of the water through the drain. When the pressure exerted by the water decreases beyond the predetermined value, because the water level in the sanitary fixture has decreased, the helical spring automatically brings back the plug to the closing position, and this because the water pressure is no longer able to counter the thrust exerted by the helical spring. Thus, the spring operates like an automatic reloading mechanism of the overflow mechanism.

The drain thus integrates an automatic overflow mechanism; the drain automatically opens to drain excess water and to prevent it from overflowing, and automatically closes when the water level reaches a value below the predetermined limit (automatic reloading).

EP-A-2281955 also describes a solution wherein the overflow mechanism is magnetic, i.e. magnets are used in alternative to the helical spring. More in detail, a first magnetic element is combined with one between a plug and a drain body, and a second magnetic or ferromagnetic element is combined with the other between the drain and plug; the magnetic elements are adapted to cooperate to allow/prevent the lowering of the plug. The operation is equivalent to the one described previously: at the exceeding of a predetermined pressure value, the magnetic elements separate from one another and the plug lowers to drain the water. Also, in this embodiment, the reloading of the overflow mechanism is automatic: the magnets cooperate to bring back the plug in a closed position when the water pressure acting on the plug decreases below a threshold value.

In other drains known in the art, the reloading of the respective overflow mechanism is done manually by the user, who must exert a thrust onto the plug with a finger, until bringing it to the position of maximum opening, before it returns in the closed position.

The Applicant has encountered the following drawbacks with regard to the use of the current drains provided with an overflow mechanism, in particular the drains in which the overflow mechanism is of the automatic reloading type. Sometimes, after a first activation of the overflow mechanism, a slight depression, caused by the drained flow of water, is created under the plug. This depression has an influence on a possible subsequent activation of the overflow mechanism: the second activation could occur upon reaching a different water level with respect to the water level that caused the first activation of the overflow mechanism. In other words, the overflow mechanism often works well the first time, thus bringing the plug in the open position upon reaching the appropriate water level defined in the calibrating step, but not the subsequent times because, as a result of the depression described above, the activation occurs unexpectedly upon reaching different water levels.

Other times, the depression generated under the plug causes instantaneous draw backs of small air volumes from the surface above the drain, and this causes a transient operation of the plug, which, instead of remaining stationary in the opening position, tends to continuously open and close, and this involves corresponding variations in the flow rate of the water drained.

A further drawback consists in the fact that, during the draining of water, vortexes or air suctions, which cause the plug to stay in the respective open position, sometimes occur at the plug of the drain. In other words, the vortexes created by the water flowing out through the drain and the air suctions sometimes prevent or slow down the return of the plug to the respective closing position.

Moreover, a further drawback consists in the fact that a return of water from the drainpipe can sometimes occur, through the drain, which pushes the plug upwards, i.e. towards the closed position, thus blocking the spillage of the water contained in the sanitary fixture for a few seconds; in other words, the return of the water along the drainpipe slows down the normal outflow of the water from the sanitary fixture to the same drainpipe, through the drain.

Some examples of drains known in the art are described in US 2012/291191 and in WO 2014/138783. EP 2711475 describes a drain of a kitchen sink provided with an aerator. The aerator is provided with a flat floater which, depending on whether or not there is water in the respective housing, closes or opens an upper aeration opening. The floater lowers to allow the passage of air, i.e. to allow air to enter at the lower zone of the sink drain, and raises itself to intercept the aeration opening and to prevent the passage of air.

Summary of the Invention

Object of the present invention is thus to provide a solution that solves the drawbacks just described, i.e. a solution that allows to achieve the effective and predictable activation of the overflow mechanism of the drain.

A first aspect of the present invention thus concerns the assembly according to claim 1 , comprising a drain of sanitary fixtures and the respective aerator.

In particular, the aerator comprises a body delimiting a housing opened on top and on the bottom that can be crossed by a flow of water, in which a drain for sanitary fixtures provided with an overflow mechanism can be inserted. The aerator comprises:

- a channel fluidically connecting a lower portion of the aforesaid housing with the outside, for example a channel that intercepts the housing on the side, and

- a floating element housed in the channel, movable between an inactive position and an active position.

In the active position, determined by the presence of water in the channel of the aerator, the latter sealingly intercepts a corresponding length of the channel and prevents the rising and spillage of water through the channel.

In the inactive position, determined by the absence of water in the channel of the aerator and by a flow of air entering the channel and directed towards the housing of the drain, the floating element does not intercept the corresponding length of the channel or it only partly intercepts it, thus allowing the passage of a flow of air, defined flow of aeration air, which enters the channel and is inserted in the housing where the drain is located, so that to aerate and stabilize the water flow being drained.

The drain was described above.

Thanks to the presence of the aerator, the water flow drained by the sanitary fixture, through the drain housed in the aerator, always stays properly aerated, i.e. receives a flow of air at the bottom of the drain which prevents localized depressions and suctions from occurring. This allows to maintain the overflow mechanism of the drain efficient, because it will always operate under the same conditions. This way, the transients causing continuous changes in the flow rate of the drained water are avoided, i.e. oscillations are avoided.

Advantageously, during the draining of water, the aerator prevents vortexes or air suctions from occurring in the drain and thus prevents the respective plug from jamming in the open position.

A further advantage consists in the fact that the aerator prevents possible returns of water from the drainpipe of the sanitary fixture. In fact, the floating element, by moving to the active position, closes the channel of the aerator (the plug of the drain closes by itself) and prevents water from rising in the sanitary fixture from the drain.

In a first embodiment, the channel is cylindrical and is formed by two branches, a first branch that is inserted transversely into the housing where the drain is located, preferably in the lower part of the housing, and a second vertical branch intercepted by the floating element. The floating element is shaped like a pin that can be inserted in the second length of the channel.

Preferably, the channel is closed on top by a vent valve.

Preferably, at least one between the floating element and the corresponding length of the channel intercepted by it is equipped with a sealing gasket, which seals against the water when the floating element is in the active position.

In this first embodiment, the active position of the floating element corresponds to a lowered position in the channel and, vice-versa, the inactive position corresponds to a raised position in the channel.

In a second embodiment, the active and inactive positions are inverted, i.e. the active position of the floating element is the raised one and the inactive position is the lowered one in the channel.

Preferably, in the second embodiment, the channel is cylindrical and the floating element is spherical.

Preferably, the channel is closed on top by a vent valve.

For example, the channel is provided, at its upper end, with a sealing gasket against which the floating element abuts when in the respective raised position.

For example, the channel is closed on top by a plug in which the vent valve and/or the sealing gasket is/are mounted.

Preferably, for both embodiments, the housing of the aerator is threaded and the drain can be screwed or embedded therein.

A second aspect of the present invention concerns the method according to claim 13 for aerating a drain of sanitary fixtures with a flow of air, during the draining of water, and for preventing the already drained water from rising in the sanitary fixture.

Brief list of the figures

Further characteristics and advantages of the invention will be better highlighted by the review of the following detailed description of a preferred, but not exclusive, embodiment illustrated by way of example and without limitations, with the aid of the accompanying drawings, in which:

- figure 1 is a schematic axial sectional view of a drain according to the known art, provided with an automatic reloading device of the overflow mechanism, shown with the plug in the normal open position;

- figure 2 is an axial sectional view of the drain shown in figure 1 , with the plug in the closed position which prevents the passage of water;

- figure 3 is an axial sectional view of the drain shown in figure 1 , with the plug in the partially open position which allows the passage of water whenever the overflow mechanism is operating;

- figure 4A is a perspective top view of a first aerator of a first embodiment of the assembly according to the present invention;

- figure 4B is a perspective bottom view of the aerator shown in figure 4A; - figure 5 is a top plan view of the aerator shown in figure 4A;

- figure 6 is an elevation side view of the aerator shown in figure 4A;

- figure 7 is an axial sectional view of the aerator shown in figure 4A, considered according to the sectional plane AB of figure 6;

- figure 8 is a perspective view of a second aerator of a second embodiment of the assembly according to the present invention;

- figure 9 is a top plan view of the aerator shown in figure 8;

- figure 10 is an elevation side view of the aerator shown in figure 8;

- figure 11 is an axial sectional view of the aerator shown in figure 8, considered according to the sectional plane AA of figure 10.

Detailed description of the invention

With reference to figures 1 -3, a drain according to the known art is identified with the reference number 1. The drain 1 comprises a substantially cylindrical body 10 adapted to be housed in an appropriate seat of an aerator 100 according to the present invention, shown in figures 4-7, in turn intended to be housed in a hole obtained in a sanitary fixture, for example a tub.

The body 10 ends at the bottom with a bottom grid 12 and at the top with an annular rosette 14 delimiting the mouth 16 for the passage of water in the drain body 10.

A plug 18 is housed in the drain body 10 to open/close the mouth 16 and thus to allow or prevent the passage of water towards the drainpipe. The plug 18 comprises a plug body 20 and a head 22 bearing a sealing element 24 adapted to cooperate with the inner edge 14' of the annular rosette 14 to hermetically close the mouth 16 when the head 22 of the plug is at the level of said rosette.

The head 22 is axially movable with respect to the body 20 of the plug between a lowered position, at which the head 22 is located under the rosette 14 and leaves the mouth 16 open, and a raised position, at which the head 22 is located at the level of the rosette 14 and sealingly closes the mouth 16.

Preferably, the plug 18 is of the snap movement type, i.e. the head 22 automatically switches, for example because pushed by an elastic element, from the lowered position to the raised position following a pressure exerted manually thereon by the user.

Preferably, when the head 22 of the plug is in the raised position, the sealing element 24 leans against a respective seat 26 obtained in the rosette. For example, the sealing element 24 is an O-ring fitted in a respective annular seat 24' obtained in the side wall of the head 22.

The plug 18 is supported by the bottom grid 12 of the body 10 of the drain 1 through an elastic element 30, i.e. an elastic element is functionally interposed between the bottom grid 12 and the plug 18 to support the latter. The elastic element 30 is calibrated so that to yield at the exceeding of a predetermined value of pressure acting on the head 22 of the plug, so that to cause a lowering of the plug 18 with respect to the drain body 10. Consequently, starting from a normally closed position of the mouth 16 of the drain 1 , shown in figure 2, the plug 18 axially translates downwards, i.e. towards the bottom grid 12, thus opening the mouth 16 and, therefore, allowing the water to outflow towards a drainpipe fluidically connected with the bottom grid 12.

The pressure acts on the head 22 by countering the force of the elastic element 30 and the hydrostatic pressure of the water contained in the tub. Once a maximum water level has been established and the corresponding value of pressure acting on the head 22 of the plug 18 has been calculated, the countering force of the elastic element 30 is selected by the manufacturer or installer so that to allow the compression of the elastic element 30 itself, and thus the lowering of the plug 18, upon reaching or exceeding such a pressure value. The drain 1 is thus provided with an overflow mechanism, which is automatically activated upon exceeding a threshold level of the water contained in the tub, so that to prevent it from overflowing. The drain 1 with the overflow mechanism active is shown in figure 3: the plug 18 is in an intermediate position with respect to the closed position shown in figure 2 and with respect to the completely open position shown in figure 1.

The overflow mechanism, comprising the plug 18 and the elastic element 30 or an equivalent magnetic element, is also configured with automatic reloading mechanism, as will now be described. When the level of water in the tub returns equal to or below that of the threshold, because the excess water was drained through the drain following the activation of the overflow mechanism, the plug 18 automatically returns into the initial closed position of the mouth 16, because pushed upwards towards such position just by the elastic element 30 or an equivalent magnetic element. Therefore, following the activation of the overflow mechanism and the compression of the elastic element 30, the plug 18 is automatically brought back to the raised position with the mouth 16 closed, when the hydrostatic pressure acting on the head 22 decreases below the threshold value.

As conceived, the drain 1 allows to avoid the prearrangement of a side hole in the tub for the overflow.

Preferably, the elastic element 30 is a helical spring, for example a tapered helical spring.

Preferably, the body 20 of the plug 18 is screwed on a bushing 32 housing and guiding the elastic element 30. The bottom grid 12 comprises a tubular axial portion 34 in which a guide stem 36 extending below the bushing 32 is slidingly inserted. Moreover, such tubular axial portion 34 defines, on top, an annular plane 38 for the elastic element 30 to lean on.

Preferably, a guide element 40, with radial fins, adapted to run along the inner walls of the body 10 of the drain 1 , is combined with the plug 18.

As described above, the drawbacks encountered with the use of the drain 1 provided with an overflow mechanism with automatic reloading mechanism are:

- sometimes, due to slight depressions caused by the outflow of the water, the proper calibration of the elastic element 30 is no longer sufficient to ensure that the overflow mechanism is always activated in the same way, i.e. upon reaching the same level of water in the tub; the depressions can in fact affect the overflow mechanism and bring it to be activated from time to time at different levels of water in the tub;

- during the draining of water, vortexes or air suctions, which cause the plug to stay in the respective open position, sometimes occur at the plug of the drain;

- sometimes, a return of water occurs from the drainpipe, through the drain, which pushes the plug upwards, i.e. towards the closed position, thus blocking the spillage of the water contained in the tub for a few seconds.

As will now be described, these drawbacks can be overcome by using the drain 1 in combination with an aerator 100 according to the present invention.

Figure 4A is a perspective top view of a first aerator 100 provided with a substantially cylindrical body 101 defining an inner housing 102 inside which a drain 1 , such as the one described above, i.e. a drain provided with an overflow mechanism with automatic reloading mechanism, can be housed.

Figure 4B shows the same aerator 100 in a perspective view, from the bottom.

Figure 5 shows the aerator 100 in a top plan view, figure 6 on the side, and figure 7 is an axial sectional view considered along the plane AB of figure 6.

In particular, in figure 7, the drain 1 properly housed in the aerator 100 is schematically denoted by a dotted line: the drain 1 and the aerator 100 form a ready-to-use assembly. The black arrows denote the direction of the water entering the drain 1 , and the direction of the water going out through the bottom grid 12 of the drain 1 and through the lower portion of the aerator 100. The aerator is provided with a side housing 103 on the side for a floating element 104, preferably shaped like a pin or mushroom. The side housing 103 delimits a channel 105 fluidically connecting the housing 102 inside the aerator with the outer environment. In particular, the channel 105 is subdivided into a first branch 105' and a second branch 105". The first length 105' is inserted transversely inside the inner housing 102 of the aerator and the second length 105" of the channel 105 vertically connects the channel 105 itself with the outer environment.

The floating element 104 is inserted in the second length 105" of the channel 105 and is movable between an inactive raised position denoted by the dotted line 104', and an active lowered position shown with a continuous line. In the raised position 104', the floating element 104 is partially extracted from the second branch 105" of the channel 105 due to a flow of air entering from the lower hole 106 present in the side housing 103. In practice, the floating element 104 is pushed upwards by the flow of air entering through the lower hole 106, crosses the second branch 105" of the channel 105, is inserted in the first branch 105' of the channel 105 and enters the inner housing 102 from here to aerate the flow of water which is drained through the drain 1 at that time. The flow of air just described is created due to the draw back exerted by the water being drained through the drain 1 , i.e. the water draws back the flow of air and the latter causes the partial raising of the floating element 104.

When the water has been completely drained through the drain 1 , the flow of air crossing the channel 105 stops and the floating element 104 goes back to the lowered position, corresponding to the closing of the second branch 105". Whenever the water rises from the drain, to prevent it from overflowing and entering the sanitary fixture, the drain 1 and the aerator 100 provide this operation: the plug 18 of the drain moves to the closed raised position, pushed by the water rising from the drain and thus prevents the spillage of water through the drain; when the drain water rising through the channel 105 reaches the height of the floating element 104, it submerges it and exerts a hydrostatic pressure thereon which pushes the floating element 104 against the lower hole 106 with sufficient force to ensure seal and, therefore, to prevent the spillage of water through the lower hole 106.

Preferably, the floating element 104 is provided with a gasket not shown for simplicity in the figures, for example of the O-ring type.

The channel 105 is closed on top by a closing element 107 omitted for simplicity in the figures, except in figure 7. The closing element is for example of the type that can be screwed or embedded and is preferably provided with a gasket.

The operation of the aerator 100 is simple: when the overflow mechanism of the drain 1 is activated and the plug 18 is lowered due to the excessive hydrostatic pressure acting thereon, a flow of air enters the lower hole 103 and, through the channel 105, enters the flow of water drained from the drain 1 , thus preventing air suctions and depressions from occurring which could keep the plug 18 in the respective lowered position, thus adversely affecting the automatic reloading of the overflow mechanism. In this circumstance, the floating element 104 is in its inactive raised position 104', at which a flow of air from the outside is allowed through the lower hole 106 and the channel 105, thus raising the floating element 104 until merging the flow of water which is being drained through the drain 1 at that time; this allows to balance the pressure in the drain 1 and to prevent localized depressions and corresponding tensions on the elastic element 30, whose task is to reload the plug 18, i.e. to bring it back to the raised position when the proper level of water has been reestablished in the tub, from occurring.

Thus, advantageously, the intervention of the aerator 100 ensures the proper operation of the overflow mechanism of the drain 1 over time, i.e. allows to achieve the activation of this mechanism upon always reaching the same threshold value of the level of water in the tub. As specified above, this is due to the fact that it prevents localized depressions, which could cause a compression of the elastic element 30 and thus change its response, from occurring.

The floating element 104 moves to the closed lowered position of the second branch 105" of the channel 105 when, during the step of draining the water, there is a return of water that temporarily makes the level of water rise in the drain 1 until the plug 18 and beyond, due to the flow rate of the siphon and of the drainpipes of the bathtub. The water itself pushes the floating element 104 against the second branch 105" of the channel 105 to intercept it. In the lowered position, the floating element 104 closes the channel 105, closing the second branch 105" in particular, because it achieves the seal by going in abutment against the edge of the second branch 105" and, therefore, prevents the return of water that could rise from the siphon and from the drainpipes up to the bathtub or overflow on the floor (the drain 1 is closed at this time). In other words, when the floating element 104 is in the lowered position, it prevents both the air from entering the channel 105 and the water from rising through the channel 105.

Preferably, the drain 1 is screwed or embedded in the aerator 100.

Figure 8 is a perspective view of a second aerator 100' provided with a substantially cylindrical body 101 defining an inner housing 102 inside which a drain 1 , such as the one described above, i.e. a drain provided with an overflow mechanism with automatic reloading mechanism, can be housed.

Figure 9 shows the aerator 100' from the top, figure 10 on the side, and figure 11 is an axial sectional view considered along the plane AA of figure 10.

In particular, in figure 11 , the drain 1 properly housed in the aerator 100' is schematically denoted by a dotted line: the drain 1 and the aerator 100' form a ready-to-use assembly according to the present invention. The arrows denote the direction of the water entering the drain 1 , and the direction of the water going out through the bottom grid 12 of the drain 1 and through the lower portion of the aerator 100'.

The aerator is provided with a housing 103 on the side for a floating element 104, preferably a sphere. The housing 103 delimits a channel 105

- IB - which fluidically connects the housing 102 inside the aerator 100' with a vent valve 106 in turn connected with the outer environment.

In particular, the vent valve 106 is positioned at the upper face of the housing 103 and the channel 105 is inserted in the lower part of the housing 102 inside the aerator.

In figure 11 , the floating element 104 is shown in two operative positions:

- a lowered position, corresponding to the inactive position, shown with the solid line, corresponding to the floating element 104 leaning on the bottom of the housing 103, away from the vent valve 106, and

- a raised position, corresponding to the active position, shown with the dotted line 104', corresponding to the floating element 104 in abutment against a gasket 107 at the vent valve 106.

In the lowered position, the floating element 104 does not close the vent valve 106 and the channel 105 stays open for the crossing of a flow of air. Instead, in the raised position, the floating element 104 stays in abutment against the gasket 107 and closes the vent valve 106, thus preventing the passage of air.

The floating element 104 stays in the inactive lowered position:

- when the plug 18 of the drain 1 is lowered to drain the water from the tub, i.e. when the overflow mechanism is activated or when the drain 1 was manually opened by the user by pushing the plug 18 to the position of maximum opening, and

- when the drain 1 is closed, i.e. when the plug 18 is completely raised to the closed position.

When the overflow mechanism is activated and the plug 18 is lowered due to the excessive hydrostatic pressure acting thereon, a flow of air crosses the vent valve 106 and, through the channel 105, enters the flow of water drained from the drain 1 , thus preventing air suctions and depressions from occurring which could keep the plug 18 in the respective lowered position, thus adversely affecting the automatic reloading of the overflow mechanism. In other words, when the floating element 104 is in its lowered position, a flow of air from the outside through the vent valve 106 and the channel 105 is allowed until the flow of water which, at that time, is being drained through the drain 1 , and this allows to balance the pressure of the drain 1 and to prevent localized depressions and corresponding tensions on the elastic element 30, whose task is to reload the plug 18, i.e. to bring it back to the raised position when the proper level of water has been reestablished in the tub, from occurring.

Thus, advantageously, the intervention of the aerator 100' ensures the proper operation of the overflow mechanism of the drain 1 over time, i.e. allows to achieve the activation of this mechanism upon always reaching the same threshold value of the level of water in the tub. As specified above, this is due to the fact that it prevents localized depressions, which could cause a compression of the elastic element 30 and thus change its response, from occurring.

The floating element 104 moves to the raised position 104' when, during the step of draining the water, there is a return of water that temporarily makes the level of water rise in the drain 1 until the plug 18 and beyond, due to the flow rate of the siphon and of the drainpipes of the bathtub. The water itself raises the floating element 104, just by floating. In the raised position 104', the floating element 104 closes the channel 105, because it achieves the seal by going in abutment against the gasket 107 and, therefore, prevents the return of water that could rise from the siphon and from the drainpipes up to the bathtub, and from dirtying the water contained therein (the drain 1 is closed at this time). In other words, when the floating element 104 is in the raised position, it prevents both the air from entering the channel 105 and the water from rising through the vent valve 106.

Preferably, the drain 1 is screwed in the aerator 100'.

Preferably, the vent valve 106 and the gasket 107 are mounted aboard a plug 108 that is screwed on the upper end of the channel 105.