ES2925887T3 - Assembly of a drain with an aerator to increase the reliability of an overflow mechanism - Google Patents

Abstract

An assembly comprising a drain (1) for toilets provided with an overflow mechanism and a respective aerator (100) is described. The aerator (100) comprises a body (101) that delimits a housing (102) open at the top and at the bottom that can be crossed by a flow of water, in which there is the drain (1) for sanitary appliances provided with a overflow mechanism. inserted. The aerator (100) comprises a channel (105) fluidly connecting a lower part of the casing (102) with the outside, and a floating element (104), housed in the channel (105), movable between an inactive position and a active position In the active position, the floating element (104) sealingly intercepts the channel (105) itself and prevents the rise and spillage of water through the channel (105). In the inactive position, the floating element does not intercept the channel (105) or only partially intercepts it, and the channel (105) can be traversed by an air flow that enters the channel (105) and is inserted into the housing (102) where the drain (1) is located, so that to aerate and stabilize the flow of water that is drained. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Assembly of a drain with an aerator to increase the reliability of an overflow mechanism Field of the invention

The present invention relates to an assembly comprising a drain for sanitary appliances, in particular a drain provided with an overflow mechanism with an automatic refilling mechanism, and an aerator, and a method for achieving correct drainage aeration during its operation.

State of the art

In the sanitary ware industry, it is known to manufacture sinks, basins and bathtubs which, for aesthetic reasons, lack the overflow hole, that is, they are not provided with the hole for draining off excess water, a hole that , in most sanitary fixtures it is arranged on the side wall to prevent the level of water contained in the sanitary fixture from exceeding a maximum value and overflowing to the outside.

Document EP-A-2281955, in the name of the Applicant, describes a drain that comprises a cylindrical body that has a lower grid at the base and, at its upper part, an annular rosette that delimits the mouth for the passage of water through of the drain body. A plug is housed in the drainage body that can be moved axially between a low position, in which the head of the plug is below the rosette and does not intercept the opening of the mouth, thus allowing the passage of the water, and a high position, in which the cap head intercepts the rosette and prevents the passage of water through the mouth.

The plug rests on the lower grille of the drainage body by means of a helical spring calibrated to yield when a predetermined pressure value is exceeded: when the volume of water contained in the sanitary device reaches and exceeds a maximum value, at the maximum level of tolerable 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 plug to descend and, therefore, the emptying 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 returns the plug to the closed position, and this is because the pressure of the water is no longer able to counteract the thrust exerted by the coil spring. In this way, the spring functions as an automatic reloading mechanism for the overflow mechanism.

The drain thus integrates an automatic overflow mechanism; the drain opens automatically to drain off excess water to prevent overflow, and closes automatically when the water level drops below the preset limit (auto recharge).

EP-A-2281955 also describes a solution where the overflow mechanism is magnetic, ie magnets are used as an alternative to the coil spring. More in detail, a first magnetic element is combined with one of a plug and a drain body, and a second magnetic or ferromagnetic element is combined with the other of a drain and a plug; the magnetic elements are adapted to cooperate to allow/prevent the descent of the stopper. The operation is equivalent to that described above: when a predetermined pressure value is exceeded, the magnetic elements separate from each other and the cap lowers to empty the water. Furthermore, in this embodiment, the recharging of the overflow mechanism is automatic: the magnets cooperate to return the plug to a closed position when the pressure of the water acting on the plug drops below a threshold value.

In other drains known in the art, the recharging of the respective overflow mechanism is carried out manually by the user, who must exert a push on the plug with a finger, until it is brought to the maximum open position, before it returns to the open position. closed position.

The Applicant has found the following drawbacks in connection with the use of current drains provided with an overflow mechanism, in particular drains in which the overflow mechanism is of the automatic refilling type.

Sometimes, after a first activation of the overflow mechanism, a slight depression is created under the plug, caused by the flow of drained water. This depression influences a possible subsequent activation of the overflow mechanism: the second activation could be produced by reaching a different water level with respect to the one that caused the first activation of the overflow mechanism. In other words, the overflow mechanism usually works fine the first time, bringing the plug to the open position upon reaching the proper water level defined in the calibration step, but not subsequent times because, as a result of the depression As described above, activation occurs unexpectedly when different water levels are reached. Other times, the depression generated under the plug causes the instantaneous entrainment of small volumes of air from the surface above the drain, which causes a transient operation of the plug that, instead of remaining immobile in the opening position, it tends to open and close continuously, which implies the corresponding variations in the flow rate of the drained water.

Another drawback is that, during the emptying of the water, vortices or air suctions sometimes occur in the drain plug, causing the plug to remain in the respective open position. In other words, the vortices created by the water coming out of the drain and the air suctions sometimes prevent or slow down the return of the plug to the respective closed position.

In addition, another drawback is that sometimes there can be a return of water from the drain pipe, through the drain, which pushes the plug upwards, that is, towards the closed position, thus blocking the discharge of water. contained in the sanitary device for a few seconds; in other words, the return of water along the drain pipe slows down the normal outflow of water from the sanitary fixture towards the same drain pipe, through the drain.

Some examples of drains known in the art are described in US 2012/291191 and WO 2014/138783.

EP 2711475 describes a kitchen sink drain provided with an aerator. The aerator is provided with a flat float which, depending on whether or not there is water in the respective housing, closes or opens an upper aeration opening. The float lowers to allow the passage of air, that is, to allow air to enter the lower drainage area of the sink, and rises to intercept the ventilation opening and prevent the passage of air.

Summary of the invention

The object of the present invention is therefore to provide a solution that resolves the drawbacks just described, that is, a solution that allows effective and predictable activation of the drain overflow mechanism to be achieved.

A first aspect of the present invention refers, therefore, to the assembly according to claim 1, comprising a sanitary fixture drain and the respective aerator.

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

• a channel that fluidly connects a lower portion of said 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 aerator channel, the aerator hermetically intercepts a corresponding length of the channel and prevents the rise and spillage of water through the channel.

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

Drainage has been described above.

Thanks to the presence of the aerator, the flow of water drained by the sanitary fixture, through the drainage housed in the aerator, always remains properly aerated, that is, it receives an air flow at the bottom of the drain that prevents depressions from occurring and localized aspirations. This allows the drain overflow mechanism to be kept efficient, as it will always work under the same conditions. In this way, transients that cause continuous changes in the drained water flow are avoided, that is, oscillations are avoided. Advantageously, during the drainage of the water, the aerator prevents vortices or suctions of air from occurring in the drainage and, therefore, prevents the respective stopper from getting stuck in the open position.

Another advantage is that the aerator prevents possible returns of water from the drain pipe of the sanitary device. In fact, the floating element, when moving to the active position, closes the aerator channel (the drain plug closes by itself) and prevents water from rising to the sanitary element from the drain.

In a first embodiment, the channel is cylindrical and is made up of two branches, a first branch that is inserted transversely into the housing in which 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 in the form of a pin which can be inserted into the second length of the channel.

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

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

In this first embodiment, the active position of the floating element corresponds to a low 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 reversed, that is, the active position of the float is raised and the inactive position is lowered in the channel.

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

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

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

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

Preferably, for both embodiments, the aerator housing is threaded and the drain may be screwed or integrated therein.

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

Brief list of figures

Additional features and advantages of the invention will become more apparent upon examination of the following detailed description of a preferred but non-exclusive embodiment, illustrated by way of example and without limitation, with the aid of the accompanying drawings, in which:

• figure 1 is a schematic view in axial section of a drain according to the known technique, provided with an automatic recharging device of the overflow mechanism, shown with the plug in the normal open position;

• Figure 2 is an axial cross-section of the drain, with the plug in the closed position, preventing 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 allowing water to pass through as long as the overflow mechanism is operating.

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

• Figure 4B is a bottom perspective 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 a side elevational 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 section plane AB of figure 6;

• Figure 8 is a perspective view of an alternate embodiment of the high pressure sanitary vent valve assembly in accordance with the present invention;

• Figure 9 is a perspective top plan view of the housing shown in Figure 8;

• Figure 10 is a side elevational 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 section 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 by the reference number 1. The drain 1 comprises a substantially cylindrical body 10 adapted to be housed in a suitable seat of an aerator 100 according to with the present invention, which is shown in figures 4-7, in turn intended to be housed in a hole obtained in a sanitary appliance, for example a bathtub.

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

A plug 18 is housed in the body of the drain 10 to open/close the mouth 16 and thereby allow or prevent the passage of water into the drain tube. The plug 18 comprises a plug body 20 and a head 22 supporting a sealing element 24 suitable for cooperating with the inner edge 14' of the annular rosette 14 to hermetically seal the inlet 16 when the plug head 22 is level. with the aforementioned rosette.

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

Preferably the stopper 18 is of the type with a spring-like movement, that is to say the head 22 passes automatically, for example due to being pushed by an elastic element, from the lowered position to the raised position following the pressure exerted manually on it. it by the user.

Preferably, when the cap head 22 is in the raised position, the sealing element 24 bears against its 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 lateral wall of the head 22.

The plug 18 is supported by the lower grid 12 of the body 10 of the drain 1 by means of an elastic element 30, that is, an elastic element is operatively interposed between the lower grid 12 and the plug 18 to support the latter. The elastic element 30 is calibrated to yield above a predetermined level of pressure acting on the plug head 22, to cause the plug to lower relative 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 moves axially downwards, that is, towards the lower grid 12, thus opening the mouth 16 and, therefore, allowing the exit of the water to a drain pipe fluidly connected to the lower grille 12.

The pressure acts on the head 22 counteracting the force of the elastic element 30 and the hydrostatic pressure of the water contained in the bathtub. Once a maximum water level has been established and the corresponding value of the pressure acting on the head 22 of the plug 18 has been calculated, the manufacturer or installer selects the opposite force of the elastic element 30 to allow the compression of the elastic element 30 itself, and this way the descent of the plug 18, when reaching or exceeding said pressure value.

Drain 1 is provided with an overflow mechanism, which is automatically activated when a threshold level of the water contained in the bathtub is exceeded, to prevent it from overflowing. Drain 1 is shown in Figure 3 with the overflow mechanism active: plug 18 is in an intermediate position with respect to the closed position shown in Figure 2 and the fully open position shown in Figure 2. Figure 1.

The overflow mechanism, comprising the plug 18 and the elastic element 30 or an equivalent magnetic element, is also configured with an automatic reloading mechanism, as will be described below. When the level of water in the bathtub returns to the same or lower than the threshold, due to the fact that the excess water was drained by the drain after the activation of the overflow mechanism, the stopper 18 automatically returns to the initial position of closing the valve. the mouth 16, because it is pushed upwards towards said position only by the elastic element 30 or an equivalent magnetic element. Therefore, after the activation of the overflow mechanism and the compression of the elastic element 30, the cap 18 automatically returns to the raised position with the mouth 16 closed, when the hydrostatic pressure acting on the head 22 decreases below the value threshold.

As it is conceived, the drain 1 makes it possible to avoid the prior provision of a side hole in the bathtub for overflow.

Preferably, the elastic element 30 is a coil spring, for example a conical coil spring.

Preferably, the body 20 of the cap 18 is screwed into a bushing 32 that houses and guides the elastic element 30. The lower grid 12 comprises a tubular axial portion 34 in which a guide rod 36 is slidably inserted, extending below the bushing 32. In addition, said tubular axial position 34 defines, above, an annular plane 38 so that the elastic element 30 rests thereon.

Preferably, a guide element 40, with radial fins, adapted to move 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 an automatic refilling mechanism are:

• sometimes, due to slight depressions caused by the outflow of water, the proper calibration of the elastic element 30 is no longer sufficient to guarantee that the overflow mechanism is always activated in the same way, that is, when reaching the same water level in bathtub; the depressions, in fact, can affect the overflow mechanism and cause it to activate from time to time at different levels of water in the bathtub;

• during the emptying of the water, vortices or air suctions sometimes occur in the drain plug, causing the plug to remain in its respective open position;

• Sometimes, there is a return of water from the drain pipe, through the drain, which pushes the cap upwards, that is, towards the closed position, thus blocking the discharge of the water contained in the bathtub during a few seconds.

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

Figure 4A is a top perspective view of a first aerator 100 provided with a substantially cylindrical body 101 that defines an internal housing 102 inside which a drain 1 can be housed, like the one described above, that is, it can be it can house a drain provided with an overflow mechanism with automatic refilling mechanism.

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

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

In particular, in figure 7, the drain 1 duly housed in the aerator 100 is schematically denoted by means of a dotted line: the drain 1 and the aerator 100 form an assembly ready for use. The black arrows indicate the direction of the water entering drain 1 and the direction of the water leaving the bottom grill 12 of drain 1 and the bottom of the aerator 100.

The aerator is provided with a lateral housing 103 for a floating element 104, preferably in the shape of a pin or mushroom. The lateral housing 103 delimits a channel 105 that fluidly connects the housing 102 inside the aerator with the outside 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 housing 102 of the aerator and the second length 105" of the channel 105 vertically connects the own channel 105 with the outside environment. Floating element 104 is inserted into second length 105" of channel 105 and is movable between a raised inactive position denoted by dotted line 104', and a lowered active position shown by solid line. 104', the floating element 104 is partially extracted from the second branch 105" of the channel 105 due to an air flow that enters through the lower hole 106 present in the lateral housing 103. In practice, the floating element 104 is pushed upwards by the air flow entering the lower hole 106, passes through the second branch 105" of the channel 105, enters the first branch 105' of the channel 105 and enters the inner housing 102 from here to aerate the flow of water draining through drain 1 at that time.The airflow just described is created due to the recoil exerted by the water draining through drain 1, i.e. the water pushes back the air flow and the latter causes partial lifting of the floating element 104.

When the water has been completely drained through the drain 1, the air flow through the channel 105 stops and the floating element 104 returns to the lowered position, which corresponds to the closing of the second branch 105".

Every time the water rises from the drain, to prevent it from overflowing and entering the sanitary installation, the drain 1 and the aerator 100 provide this operation: the drain plug 18 moves to the raised closed position, pushed by the water that rises from the drain and therefore prevents the spillage of water through the drain; when the drainage water that rises through the channel 105 reaches the height of the floating element 104, it submerges it and exerts a hydrostatic pressure on it that pushes the floating element 104 against the lower hole 106 with sufficient force to ensure sealing and thus prevent spillage of water through the lower hole 106.

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

The channel 105 is closed at its 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. of a board.

The operation of the aerator 100 is simple: when the drain overflow mechanism 1 is activated and the plug 18 is lowered due to excessive hydrostatic pressure acting on it, an air flow enters the lower hole 103 and, through of the channel 105, enters the flow of water drained from the drain 1, thus preventing the occurrence of suctions and air depressions that could keep the plug 18 in the respective lowered position, negatively affecting the automatic recharging of the overflow mechanism. In this circumstance, the floating element 104 is in its raised idle position 104', in 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 combine the flow of water being drained through drain 1 at that time; this allows to balance the pressure in the drain 1 and to avoid localized depressions and the corresponding stresses in the elastic element 30, whose task is to recharge the plug 18, i.e. return it to the raised position when the adequate level of water has been restored in the bathtub.

In this way, advantageously, the intervention of the aerator 100 ensures the correct operation of the overflow mechanism of the drain 1 over time, that is, it allows the activation of this mechanism to always reach the same threshold value of the level of water in the bathtub. As specified above, this is due to the fact that it prevents localized depressions from occurring, which could cause compression of the elastic element 30 and, therefore, modify its response.

The floating element 104 moves to the lower closed position of the second branch 105" of the channel 105 when, during the water emptying stage, a return of water occurs that temporarily raises the water level in the drain 1 to the stopper 18 and beyond, due to the flow rate of the siphon and of the drainage tubes of the bathtub.The same water 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 in particular the second branch 105", since it seals by resting against the edge of the second branch 105" and, therefore, prevents the return of the water that it could go up the siphon and drain pipes into the tub or overflow onto the floor (drain 1 is closed at the moment). In other words, when the floating element 104 is in the lowered position, it prevents both air from entering channel 105 and water from rising up 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 that defines an internal housing 102 inside which a drain 1 can be housed, like the one described above, that is, a drainage provided with an overflow mechanism with automatic recharge mechanism.

Figure 9 shows the aerator 100' from above, Figure 10 is a side view, and Figure 11 is an axial sectional view taken along plane AA of Figure 10.

In particular, in figure 11, the drain 1 duly 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 indicate the direction of the water entering the drain 1 and the direction of the water leaving the bottom grid 12 of the drain 1 and the bottom 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 that fluidly connects the housing 102 inside the aerator 100' with a ventilation valve 106 which in turn is connected to the outside environment.

In particular, the vent valve 106 is located in 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 operating positions:

• a lowered position, corresponding to the idle position, shown by the solid line, corresponding to the floating element 104 resting on the bottom of the housing 103, away from the vent valve 106, and

• a raised position, corresponding to the active position, shown by the dotted line 104', which corresponds to the floating element 104 resting against a gasket 107 on the vent valve 106.

In the lowered position, the floating element 104 does not close the vent valve 106 and the channel 105 remains open for the passage of an air flow. Instead, in the raised position, the floating element 104 remains in contact with the seal 107 and closes the vent valve 106, thus preventing the passage of air.

The floating element 104 remains in the lowered inactive position:

• when the plug 18 of the drain 1 is lowered to empty the water from the bathtub, that is, when the overflow mechanism is activated or when the drain 1 was opened manually by the user by pushing the plug 18 to the maximum open position, Y

• when drain 1 is closed, ie when plug 18 is fully raised to the closed position.

When the overflow mechanism is activated and the plug 18 descends due to excessive hydrostatic pressure acting on it, an air flow passes through the vent valve 106 and, through the channel 105, enters the flow of water drained from the drain. 1, thus preventing the occurrence of suctions and air depressions that could keep the plug 18 in the respective low position, thus negatively affecting the automatic recharging of the overflow mechanism.

In other words, when the floating element 104 is in its lowered position, a flow of air from the outside is allowed through the vent valve 106 and channel 105 to the flow of water, which is currently being drained. through drain 1, and this makes it possible to balance the pressure of drain 1 and prevent localized depressions and the corresponding stresses from occurring in the elastic element 30, whose task is to recharge the plug 18, that is, to bring it back to the position raised when the proper level of water in the tub has been restored. In this way, advantageously, the intervention of the aerator 100' ensures the correct operation of the overflow mechanism of the drain 1 over time, that is, it allows the activation of this mechanism to always reach the same threshold value of the level of water in the bathtub. As specified above, this is due to the fact that it prevents localized depressions from occurring, which could cause compression of the elastic element 30 and, therefore, modify its response.

The floating element 104 moves to the raised position 104' when, during the water emptying stage, a return of water occurs that temporarily raises the water level in the drain 1 up to the plug 18 and beyond, due to the flow rate of the siphon and tub drain pipes. The water itself lifts the floating element 104, only by buoyancy. In the raised position 104', the floating element 104 closes the channel 105, since it achieves the seal by resting against the joint 107 and, therefore, prevents the return of the water that could rise from the siphon and from the drainage pipes. to the bathtub, and dirty the water contained in it (drain 1 is closed at this time). In other words, when the floating element 104 is in the raised position, it prevents both the entry of air into the channel 105 and the rise of water through the vent valve 106.

Preferably, the drain 1 is threaded into the aerator 100'.

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

Claims (13)

1. A set consisting of: A) a drain (1) for plumbing fixtures, provided with: A1) a plug (18) axially movable between a low position, in which the plug (18) does not intercept the upper opening of the housing (102) of the aerator (100) mentioned in point B, thus allowing the passage of the water, and an elevated position, in which the plug (18) intercepts said opening and prevents the passage of water, and A2) an overflow mechanism, which supports the plug (18) and which is calibrated to yield when exceeding a predetermined value of hydrostatic pressure that acts on the plug itself (18), thus causing the descent of the plug (18) and , therefore, the emptying of the water through the drain (1), characterized by B) an aerator (100) comprising a body (101) delimiting a housing (102) that can be crossed by a flow of water, in which the drain (1) is inserted, and B1) a channel (105) that fluidly connects a lower portion of said housing (102) with the outside, B2) a floating element (104) housed in the channel (105), mobile between an active position, in which it intercepts hermetically seals the channel (105) and prevents the rise and spillage of water through the channel (105) itself, and an inactive position (104'), in which it does not intercept the channel (105) or only partially intercepts it, and the channel (105) can be traversed by a flow of aeration air that enters said housing (102) and is drawn towards the drain (1). Assembly according to claim 1, in which the active position of the floating element (104) corresponds to a raised position (104') in the channel (105), and the inactive position of the floating element (104) corresponds to a lowered position in the channel (105). 3. Assembly according to claim 1 or claim 2, in which the channel (105) is cylindrical and the floating element (104) is spherical. Assembly according to one of the preceding claims, in which the channel (105) is closed at its upper part by a ventilation valve (106). Assembly according to any one of the preceding claims 2-4, in which the channel (105) is provided, at its upper ends, with a gasket (107) against which the floating element (104) enters in contact in the raised position (104'). 6. Assembly according to any one of claims 1 to 3 and 5 when it depends on one of claims 2 or 3, in which the channel (105) is closed at its upper part by an element inside which is tá mounted a vent valve (106) and/or a gasket (107). Assembly according to claim 1, in which the active position of the floating element (104) corresponds to a lowered position in the channel (105), and the inactive position of the floating element (104) corresponds to a raised position (104') in the channel (105). 8. Assembly according to claim 1 or claim 7, in which the channel (105) is cylindrical and the floating element (104) is shaped like a pin or mushroom. Assembly according to one of the preceding claims, in which the channel (105) is closed at its upper part by a removable closing element (107). Assembly according to any one of the preceding claims 7-9, in which the channel (105) is divided into a first branch (105') and a second branch (105") and the floating element (104) slides into the second branch (105"). Assembly according to claim 10, in which the second branch (105") of the channel (105) and/or the floating element (104) are provided with a sealing gasket. 12. Assembly according to one of the preceding claims, in which the drainage (1) for sanitary appliances can be screwed or embedded in the body (101), inside the housing (102) that can be passed through by water . 13. A method for aerating a drainage (1) of plumbing fixtures with a flow of air, during the emptying of water, and for preventing the already emptied water from rising in the plumbing fixture, comprising: a) arranging an aerator (100, 100') comprising a body (101) delimiting a housing (102) that can be traversed by a flow of water in the drainage hole of a sanitary appliance, and comprising: - a channel (105) fluidly connecting a lower portion of said housing (102) of the aerator (100, 100') with the outside, - a floating element (104) housed in the channel (105), movable between an active position, in which it hermetically intercepts the channel (105), and an inactive position (104'), in which it does not intercept the channel (105 ) or intercepts it only partially, b) housing a drain (1) in the housing (102) of the aerator (100, 100'), in which the drain (1) is provided with a plug (18) movable axially between a low position, in which the plug (18) does not intercept the upper opening of the housing (102) of the aerator (100, 100'), thus allowing the passage of water, and an elevated position in which the plug (18) intercepts said opening and prevents the passage of water, and which comprises an overflow mechanism, which supports the plug (18) and which is calibrated to give way when a predetermined value of hydrostatic pressure is exceeded that acts on the plug itself (18), thus causing way the descent of the plug (18) and, therefore, the drainage of the water through the drain (1), c) by the floating element (104), move to the inactive position due to a flow of aeration air that passes through the channel (105) of the aerator (100, 100') dragged by the drain (1), and d) when moving the floating element (104) to the active position, in case of return of the water through the drainage of the sanitary appliance, due to the force exerted by the rising water, hermetically intercept the channel (105) of the aerator and prevent the rise and spillage of the water.