Field of the invention

The present invention pertains to devices for blocking the rising or backflow of water in floor drains, and especially such devices which are suitable for being inserted without other, major interventions in the drain system into a floor drain from which there is expected a risk of backflow of water from the drain system, which are suitable for being removed for inspection, cleaning and possibly repair or replacement, which to a minimal degree block the through flow of water down into the floor drain, and which can be adapted to floor drains of different constructions and dimensions within a certain tolerance interval.

Background of the invention and prior art

In recent years there has been a comprehensive discussion of the risk of climate changes as a consequence of the socalled greenhouse effect, and there are expectations of increased frequency of severe storms with extreme precipitation and of rising sealevels. In recent years there has already been a number of occurrences of extreme precipitation which have led to flooded cellars. Experts in sewer and drain systems claim that it will be economically impossible to build out exsisting and future sewer systems to such a capacity that flooding and outflow of water from sewers into cellars can be avoided in all cases.

For the individual homeowner who is affected by flooding, the experience is highly stressing. It inevitably entails disruption of the everyday life, a significant clearing and cleaning effort, in many cases loss of personal effects that are irreplaceable such as photographs and items with a sentimental value, risk of permanent damage to the house and economical losses that are not in all cases covered by insurance. This applies whether the flooding has a general and comprehensive character such that for instance the terrain around the house is flooded, or it is the case of a minor flooding with only a few cm of water in the most lowlying parts of the cellar. A special problem is the risk of bad smell which can arise in connection with ingress of sewer water and which can remain long after the water has been pumped away and is dried out.

General and comprehensive floodings of the terrain around a building are not easily coped with, but in many cases floodings of lowlying cellar rooms arise slowly by the ingress of water through a floor drain that is placed in the cellar room. The problems can arise as a consequence of torrential showers of rain, but they may also arise in connection with high tides in coastal areas or in the neighborhood of harbours, and in these cases there is often given a warning of perhaps several hours or half a day. But also torrential showers of rain may be detected and can be warned against, and there are plans to establish local weather radars and automatic warning via SMS messages at different places where there is deemed to be a special risk of flooded cellars in connection with torrential showers of rain. With such arrangements one may expect a warning of perhaps a quarter of an hour to one hour, also because it will take several minutes from the moment a torrential shower of rain starts and until the sewer system is overloaded and backflow into the cellars occurs.

Irrespective of such warnings many homeowners will nevertheless find themselves in the frustrating situation that they can see the start of rising and backflow of water in the drains, but they are unable to prevent it. Therefore there is according to the invention provided a device that is designed to be able to be inserted into a floor drain without major intervention in the drain system, that is arranged to be inserted and to be taken out for inspection and maintenance, but that is designed in such a manner that it is suitable to remain installed in the the floor drain for a long time, as the device is designed such that normal outlet of water down into the floor drain is not prevented.

By a floor drain is understood an element that is suitable to be installed in a floor to create access to a drain system. Floor drains are generally cylindrical, fairly thinwalled constructions of metal or plastic with a diameter of from a few cm up to typically 10 or 15 cm, and they are suitable for example to be cast into concrete or in other ways to be fixed level with, but below a floor surface and to be connected with a drain pipe. They are generally installed with their cylinder axis substantially in a vertical orientation. They are typically suitable for receiving directly or indirectly via an adapter piece a grille or the like for visuel screening of the floor drain and in order to prevent that objects with not too small dimensions fall down into the floor drain. A floor drain may be provided with a bottom, such that the floor drain has the character of an upward open, cylindrical vessel, but with outlet of water to the drain system through a pipe that is installed in the side of the floor drain, that is typically as a spout on the cylinder surface and often near to the bottom of the floor drain, or the floor drain may be a substantially cylindrical piece of pipe that is open in both ends, such that the first connecting pipe of the drain system continues axially with respect to the floor drain. There can be an adaptation of the diameters of respectively the floor drain and the drain pipe which typically has the smaller diameter, which adaptation can have the character that the floor drain is provided with a bottom with a through port and a spout in an axial, that is substantially vertical orientation.

Floor drains are often equipped with a trap, that is a construction which catches a volume of water in such a way that direct access for gas from the drain system

(sewer gas) to the area above the floor drain is blocked, but which allows passage of water, and which is known to those skilled in the art. Such a trap may be permanently installed in the floor drain, but it may also be removably installed in the floor drain, or it may be realized in a part of the drain system in immediate proximity to its connection til the floor drain. If the trap is located in a part of the drain system in immediate proximity to its connection to the floor drain, it will often be placed such that water is catched to a level that is above a possible bottom in the floor drain.

When the device according to the invention must be suitable to remain installed in the floor drain for a long time, it is important that the device has properties such that: it does not risk to relax after a certain time and leave a sealing engagement with the floor drain when the water level in the drain system is low, it allows water which may be located above the device to pass through the device under the influence of the force of gravity and therefore not as a consequence of the activation of a pump or the like that is dependent of manual activation or of the presence of a reliable source of power at the same time as rising of water through the device is blocked it allows water passing through the device from above the device to pass with a flow velocity that is not impaired with respect to the flow velocity in the absence of the device to such an extent that the purpose of the floor drain, which is to remove water from those rooms wherein the floor drain is located, will be prevented or substantially impaired.

Furthermore it is advantageous if the device can be adapted to floor drains with dimensions within an interval of different diameters.

When a device that exhibits the above described properties is installed in a floor drain, doubt will arise after a certain time whether the function of the device for blocking the backflow remains, as the device usually is not and only in exceptional cases will be exposed to rising water from the drain system. It is therefore desirable that the device can be removed for inspection, cleaning and possible repair.

It is the purpose of the invention to provide a flexible device which can be adapted to a range of models of floor drains and which makes it possible for a homeowner to block backflow of water from a floor drain in a situation where there is risk of rising of water from the floor drain with consequent flooding of cellar rooms.

It is a further purpose of the invention to provide a device that at least periodically easily can be removed from the installed position in a floor drain for inspection, cleaning and possibly repair or replacement. It is yet a further purpose of the invention to provide a device that makes it possible to prevent the said problems with rising of water from a floor drain and flooding of cellar rooms while the said important properties are respected.

According to the invention there is provided a device that meets the said purposes.

In the prior art there are devices for permanent location in a drain system, socalled anti-backflow valves that can prevent backflow from the general sewer system to the sewer pipes below a house. Such devices are expensive to install and they require inspection and maintenance in order to ensure that they actually will function in the hopefully rare cases where they are required.

In the prior art there are flexible devices for permanent blocking of a drain pipe. Such a device is described in EP 0 682 204. This device is not suitable for temporary insertion and is therefore not designed so that it can be quickly installed by a none professional operator and can be removed after use. This device does not allow through flow of water in the direction of flow for the drain pipe when it is inserted.

In the prior art there are flexible devices for permanent positioning and for temporary blocking of a pipe, for instance a drain pipe. Such a device is described in DE 20 2005 007 788 Ul. This device is not designed so that it can be quickly inserted into a drain pipe by a none professional operator, and even though it can be rendered not operational, it is not designed to be removed after use. This device does not allow through flow of water in the direction of flow for the drain pipe when it is activated.

In the prior art there are floor drains that are designed so that it is possible to insert a removable trap insert down into the floor drain, and there are also designs of such trap inserts that are designed with a one-way valve which with the one-way valve function prevents backflow of rising water from the drain system through the trap insert and up out of the floor drain. Such a trap insert with one-way valve function is described in EP 1 561 869 and is marketed by the company Blϋcher Metal A/S from Vildbjerg in Denmark with the designation Multitrap, product code 503.000.110. These trap inserts, however, have a fairly small area for through flow as the difference between the diameter of the trap the element itself in the trap insert and the diameter of the floor drain amounts to only about 10 % of the diameter of the floor drain and is furthermore partly blocked by the valve element, whereby the area for through flows is less than 20 % of the total area of the floor drain. The fairly low area for through flow is partly because the one-way valve element is designed as a loose rubber washer that rests on two horizontal sealing surfaces of metal with a certain radial extent. This additionally leads to a risk that particles or other contamination may be deposited on the sealing surfaces and the rubber washer during normal operation and that the thus contaminated sealing elements will not be sealing and thereby operative when rising of water occurs in the drain, and the oneway valve element must block the backflow. Furthermore these trap inserts are designed for use exclusively with a specific floor drain which is marketed by the same manufacturer, as they are designed with a diameter that is matched to the floor drains to which they belong, and their sealing element with respect to the inner surface in the floor drain thus can not be expanded in a controlled manner in order to be adapted to a range of floor drains with a range of dimensions. The said Multitrap from Blϋcher Metal A/S is, however, equipped with other flexible elements in the form of curved leaf springs in a radial orientation from a central adjustment member and out to the circumference of the trap element, where the leaf springs rest on the upper edge of a flange for the sealing element, which sealing element is in the form of an O-ring. The leaf springs are in a not tightened position connected to the adjustment member in an axially displaced position with respect to the flange for the sealing element, and by tightening of the adjustment member their central position is displaced axially in the direction towards the plane for the flange, whereby the ends of the spring elements are displaced outwards and enter into a locking engagement with the inner surface in the drain. Summary of the invention

The invention comprises a device for blocking rising or backflow of water in a floor drain that comprises a main element which can be brought into a sealing engagement with an inner wall in a floor drain, and a one-way valve element which allows water that may be located above the device to flow through the device and out into the floor drain system, provided that the water level in the floor drain system is low, but which closes, when water rises in the drain system and thereby in the floor drain, and there thus is a risk of rising of water from the drain system and into the rooms wherein the floor drain is located. In preferred embodyments of the invention the device comprises a flexible sealing element which by mechanical means can be expanded to fill out the cross section of the floor drain in a sealing manner and preferably in a manner such that the element is held fixed in place in the floor drain and such that the mechanical means at a later time, for instance if there is a wish for inspection or cleaning of the device, can be relieved and allow contraction of the flexible element. The device also comprises means which are suitable to guide the introduction of the device into and the removal of the device from the floor drain.

In preferred embodyments of the device according to the invention, the one-way valve element consists of a floating valve element. In further embodyments of the invention the floating valve element is biased by a spring towards its closed position in such a way that the floating valve element assumes its open position when it is not lifted by rising water, but buoyancy from rising water cooperates with the bias force from the spring in order to close the floating valve element. In yet further embodyments of the invention the one-way valve can be blocked in its closed position. In preferred embodyments of the invention the one-way valve comprises a flexible sealing element that in the open state of the one-way valve is not in contact with water, and a sharp edge on the floating element that enters into a sealing engagement with the flexible sealing element when the one-way valve closes. In a first embodyment the device comprises mechanical means which can bring about expansion of the device to fill out the cross section of the floor drain and which consists of a central and axially placed screw mechanism that can pull two with respect to each other axially displaced located parts of the device together such that one or several intermediately placed, flexible elements are deformed and are pressed out towards the inner surface in the floor drain to a sealing engagement, and the device comprises a centrally located passage for water which is provided with a oneway valve and which is placed as a lumen in the centrally located screw mechanism.

In a second embodyment of the invention the device according to the invention further comprises the function of a trap. The function of the trap may be incorporated in the function of the one-way valve as it is the case in the above mentioned prior art, or the function of the trap may be separate.

Brief description of the drawings

In the following the invention will be described in further detail with reference to the appended drawings wherein the same reference numbers are used for the same details through the several figures.

Fig. 1 shows in vertical cross section a floor drain from the prior art for casting into concrete.

Fig. 2 shows in vertical cross section a trap insert from the prior art installed in a floor drain according to Fig. 1 and with a one-way valve function for blocking of rising water from the drain system.

Fig. 3 shows a horizontal cross section along the line A - A of the trap insert that is shown in Fig. 2 Fig. 4 shows in vertical cross section a device according to a first embodyment of the invention which is shown inserted in a floor drain and respectively in the right and in the left side of the drawing is shown in the right side arrangered to a sealing engagement with the inner surfaces in the floor drain and in a state where the valve is open, and is shown in the left side arrangered out of a sealing engagement and in a state where the valve is closed.

Fig. 5 shows a horizontal cross section along the line a - a of the device according to the invention that is shown in Fig. 4.

Fig. 6 shows in vertical cross section a device to guide the introduction of the device that is shown in Fig. 4, down into the floor drain and to tighten the device to a sealing engagement with the floor drain or to relieve the tightened state prior to removal of the device.

Fig. 7a and 7b show different views of a screening cover from the device that is shown in Fig. 4.

Fig. 8 shows in vertical cross section a device according to another embodyment of the invention which is shown inserted into a floor drain and respectively in the right and the left side of the drawing is shown in the right side arrangered to a sealing engagement with the inner surfaces in the floor drain and in a state where the valve is open, and is shown in the left side arrangered out of a sealing engagement and in a state where the valve is closed.

Fig. 9 shows in vertical cross section an alternative embodyment of a part which comprises the main element, the sealing elements and the tightening device for these from a device according to a first or a second embodyment of the invention, and which respectively in the right and the left side of the drawing is shown in the right side arrangered to a sealing engagement with the inner surfaces in the floor drain, and is shown in the left side arrangered out of a sealing engagement. Description

Fig. 1 shows a floor drain according to the prior art which is manufactured from thin metal plate, and Fig. 2 shows a trap element with a one-way valve function according to the prior art which is also manufactured substantially from thin metal plate and which is designed for mounting in the floor drain from Fig. 1.

In Fig. 1 and the following drawings, the direction vertical up is in all places indicated with an arrow with the designation "UP". The floor drain 100 from Fig. 1 which comprises a part 101 that is designed as a substantially cylindrical body with an end flange 102 at the top and with a downward directed spout 103 at the bottom, is intended for casting into concrete. The floor drain 100 further comprises an adapter piece 104 for mounting of a grille 105.

In a cylindrical part of the floor drain 100 there can be mounted a trap element 110 which is not a part of the invention, which is shown in Fig. 2, and which comprises a funnel-shaped part 111 and a cup 112. The funnel 111 is provided with a flange 113 with a groove for an O-ring 114 and a fitting 115 in the form of a radial beam which is fixed to the funnel 111 near to the edge, and which comprises a central, axially threaded bushing 116 wherein there is installed a screw 117 as adjustment member. The screw 117 is in engagement with a fastener 118 in the form of three leaf springs that extend radially from a hub which is in engagement with the screw. The three leaf springs are curved, they are positioned with angles of 120 ° with respect to each other, and they rest with their pointed ends on the upper edge of the flange 113. In the not tightened state of the screw 117, the hub from the fastener 118 is axially displaced from the plane of the flange 113 and the points of the leaf springs do not axially extend beyond the flange 113. By tightening of the screw 117 the position of the hub from the fastener 118 is displaced axially towards the plane for the flange 113, and the leaf springs are thereby deformed to a position wherein their pointed ends extend beyond the flange 113 and beyond the outer diameter of the O-ring 114 and enter into a locking engagement with the inner surface in the floor drain as it is shown in Fig. 2.

Above the upwards facing edge on the cup 112 there is placed a sealing element 119 in the form of a washer of a rubber material which in the left side of Fig. 2 is shown in its radially uppermost position to which it is brought by the outflowing water that has raised it to this position, and which in the right side of Fig. 2 is shown in its axially lowest position where it rests in a sealing engagement partially on an upwards facing surface on an annular flange 120 that is welded on the funnel 111 in a sealing manner, and partially on an upwards facing surface on an annular flange 121 that presents an upper termination of the cup 112. The cup 112 is installed on three downwards facing webs 122 on the outer circumference of the flange 120 with radially placed screws 123 which are provided with not shown gaskets between the heads of the screws and the outer surface of the cup. In the area between the location of the screws 123 and the flange 121, the cup is of conical shape such that there is located an annular gap between the two flanges 120 and 121, through which water can pass from the inner part of the cup 112 and out above the edge of the flange 121 and further down into the drain. During such passage of water, the sealing element 119 rises and thereby allows the passage. If on the contrary water rises in the drain, then the sealing element will assume its sealing position and normally be further pressed forcefully into this under the influence of the pressure from the rising water, whereby backflow of water through the device is blocked.

The cup will retain water to the level of the flange 121 which is above the level of the lowermost edge of the funnel, whereby passage of sewer gas is prevented as the cup, the funnel, and the retained water act as a trap. The cup thus acts both as a oneway valve and as a trap.

Installation of the trap element 110 in the floor drain 100 is performed thereby that the trap element with the screw 117 in a not tightened state is introduced down into the floor drain in such a way that the axes for the cylindrical part of the floor drain and for the funnel 111 are coincident, and such that the O-ring 114 enters into a sealing engagement with the inner, cylindrical surface in the floor drain. Thereafter the screw 117 is tightened, whereby the ends of the leaf springs from the fastener 118 enter into a locking engagement with the inner, cylindrical surface in the floor drain.

In Fig. 3 there is shown a cross section of the device from Fig. 2 taken along the line A - A. This cross section is suitable to illustrate respective areas for the through flow. In the cross section, water during its passage to the sewer system flows downwards in the central, circular area, the water flows upwards in the annular area between the flanges 120 and 121, and the water flows downwards in the annular area between the flange 121 and the wall in the drain 100. It is seen that the flanges 120 and 121 together take up a significant part of the total cross sectional area of the drain, and the areas for through flow are therefore significantly reduced relative to their theoretical maximum value of 1/3 of the totale cross sectional area of the floor drain.

In a first embodyment of the invention that in Fig. 4 is shown in cross section and as placed in a floor drain 100, the device consists of a main element 10 in the form of a cylindrical element with a through lumen. In Fig. 4, the device is shown on the left side of the cylinder axis for the main element in its closed position, that is in a position wherein the device blocks for flow of water through the drain, whereas the device on the right side of the cylinder axis is shown in its open position, that is in a position wherein the device allows flow of water through the drain. Further the device is shown in Fig. 4 on the left side of the cylinder axis for the main element in a position out of engagement with the inner wall in the floor drain 100, whereas it on the right side of the cylinder axis is shown in engagement with the inner wall in the floor drain 100.

The main element has an outer surface, the diameter of which along the major part of the main element is somewhat smaller than the diameter of the drain pipe 100, but which on the one end has a flange-like, radial extension 14. On the outer surface of the main element there are positioned two circumferential, deformable sealing elements 18 and 22 that during use of the device are brought into a sealing engagement partly with three annular spacers 16, 20 and 24 and partly with the inner surface in the drain pipe 100. The sealing elements 18, 22 are in this embodyment two substantially identical, flexible rings with substantially circular cross section that, as it is shown in Fig. 4, may be massive, or they may be hollow and filled with a gas or a liquid. The sealing elements 18, 22 are preferably massive rings in order to avoid the risk of loss of gas or liquid. The sealing elements may be manufactured from a suitable natural or synthetic rubber material, a flexible polymer material such as polyurethan, or the like.

The first sealing element 18 is positioned immediately adjacent to a first, annular spacer 16 that has a bevelled face which is facing the sealing element 18, and a radial face which is at a right angle to the axis of the cylinder and which is facing the extension 14, and between the first sealing element 18 and the second sealing element 22 there is positioned a second, annular spacer 20 which is designed as a substantially cylindrical bushing with bevelled faces for contact with the two sealing elements 18, 22. On the other side of the second sealing element 22 there is positioned a third, annular spacer 24 which is designed as a substantially cylindrical bushing with one bevelled face for contact with the second sealing element 22 and one end face that is at a right angle to the axis of the cylinder and is opposite to the second sealing element 22. The two of the spacers 20 and 24 are each provided with a cylindrical extension, respectively 20' and 24' that can be moved in below their respective neighboring elements respectively 16 and 20, and they are each provided with indentations at the junctions between the bevelled faces and the cylindrical extensions 20' and 24' that are adapted to receive the edges at the ends of the bevelled faces on their respective neighboring elements, respectively 16 and 20. Thereby the spacers can be moved close together, as it is shown to the right of the central axis in Fig. 4, and the annular spaces between the bevelled faces can thereby achieve a triangular cross section, whereby the sealing elements 18, 22 are displaced outwards, as it is also shown.

The end face at a right angle on the spacer 24 is adjacent to a collar 26 which is a substantially cylindrical bushing that is provided with an outer thread 28 which is in engagement with an inner thread 12 on the main element 10. The collar comprises a flange-like, radial extension 26' that is provided with one surface which is at a right angle to the axis of the cylinder, and which is in contact with the spacer 24, while there between the spacer 24 and the collar 26 optionally may be inserted a not shown disc of a friction reducing material. The opposite surface on the flange-like extension 26' of the collar 26 is conical and is provided with a plurality of two or more driver holes 30 which are angularly evenly spaced on the surface and which are designed to be engaged with a corresponding number of studs 74 on a driving collar 72 from a tightening tool. The tightening tool that is shown in Fig. 6 further consists of a central element 70 that can be brought into guiding engagement with the main element 10, while turning of the central element 70 with respect to the main element 10 can be prevented thereby that two webs 73 on the bottom edge of the central element 70 with T-shaped slots at the bottom are brought into engagement with a lateral beam 34 in the lumen of the main element. The driving collar 72 is further provided with a handle 76, and the central element 70 is further provided with a handle 78, whereby the driving collar 72 and the central element 70 can be turned with respect to each other, whereby the collar 26 can be screwed on or off the thread on the main element 10 when the driving collar 72 is in engagement with the collar 26 and the central element 70 is in engagement with the main element 10.

The sealing elements 18 and 22 are in this way positioned in two wedge-shaped spaces as the sealing element 18 is located between the bevel on the spacer 16 and the one bevelled face on the spacer 20, and the sealing element 22 is located between the second bevelled face on the spacer 20 and the bevelled end face on the spacer 24. As it is apparent from Fig. 4, the orientation of the bevels on these four faces are arrangered so that the wedge-shaped spaces become broader radially outwards. As it is shown to the right of the central axis in Fig. 4, when the collar 26 tightens the main element 10, it presses the spacer 24, the sealing element 22, the spacer 20 and the sealing element 18 together towards the spacer 16, whereby the wedge-shaped spaces are reduced in axial extent. Thereby the sealing elements 18, 22 are forced outwards and enter into a sealing engagement with the inner surface in the floor drain 100.

It is noted that because of the flexibility of the sealing elements, these can compensate for a certain difference in diameter between the main element 10 and the inner surface in the drain pipe 100, whereby the device can be used together with drain pipes whose inner diameters vary within a certain interval. In Fig. 4 there is indicated by the broken lines b - b and c - c the minimal, radial extent of a floor drain wherein the device can be introduced, and as shown this extent is smaller than the extent of the floor drain 100.

The sealing element 18 will create a sealing between the spacer 16 and the inner surface in the drain pipe 100, and there is created a sealing between the spacer 16 and the extension 14 of the main element 10 either thereby that the spacer 16 is permanently and sealingly united with the extension 14 by bonding, soldering or welding, thereby that the spacer 16 is manufactured in one piece together with the extension 14, thereby that the spacer 16 is manufactured from a material such as for instance polyuretan that in itself can enter into a sealing engagement with the extension 14, or thereby that between the extension 14 and the spacer 16 there is placed a not shown sealing element which for instance is in the form of a rubber washer.

Those skilled in the prior art will recognize that only the one sealing element 18 needs to have a sealing function, and that the second sealing element 22 as well as the spacer 24 therefore could be omitted, but it is advantageous to incorporate two rings 18, 22 in the device according to the first embodyment of the invention for the purpose of safe guidance of this with respect to the floor drain 100, for instance in order to avoid that the device according to the invention becomes misaligned, such that its axis is brought to deviate from the axis for the floor drain. It is also evident that the device according to the first embodyment of the invention could be provided with further sealing elements and spacers, but this would be disadvantageous, partly because it would make the construction more expensive and complicated, and partly because it would create a risk that the sealing element 18 does not enter into a correct, sealing engagement with the inner surface in the floor drain.

The lumen in the main element 10 is provided with a floating valve construction that can block the lumen. On the left side of the cylinder axis in Fig. 4, the floating valve construction is shown in its closed position for the main element, that is in a position wherein the device blocks for flow of water through the drain, whereas the floating valve construction on the right side of the axis of the cylinder is shown in its open position, that is in a position wherein the device allows flow of water through the drain. The floating valve construction is suspended from a lateral beam 34 which is placed within and across the lumen and which is provided with a centrally located guiding bushing 36 with a through hole on the axis of the cylinder. The floating valve element itself consists of an upwards facing cup 40 with an upwards facing edge with a sharp termination 42. The sharp edge 42 is designed for engagement with a flexible sealing element 44 which is mortised into the downwards facing end face on the main element 10 and which may be manufactured of the samme type of material as the sealing elements 18, 22. As it is shown in Fig. 4, the sealing element 44 can have et trapezoidal cross section and thereby be retained in a groove that also has a trapezoidal cross section, in the manner of a dovetail guideway. The sealing element is protected against contact with water by a downwards facing funnel 32 which in a sealing manner is connected with the circumference of den bottom surface of the main element 10 adjacent to the lumen in the main element 10. The cup hangs in a rod 46 which passes through the hole in the guiding bushing 36 and which above the latter is provided with a stop 52 which is secured to the rod with a disc 54 and a split pin 56 through a cross hole near the end of the rod 46 and which prevents the rod 46 from the floating valve element from falling out of the hole in the guide bushing. The stop is preferably designed as a downwards facing cup in order to guide water that must pass the device away from the guiding bushing in order to avoid blocking of the free passage of the rod 46 in the hole in the guiding bushing 36 because of contamination. The cup 40 from the floating valve element is provided with a buoyancy element 62 that advantageously may be protected against contact with the outflowing water by means of a downwards facing edge 64, if it as it is shown in Fig. 4 merely consists of an unshielded piece of cork or polystyrene foam. The buoyancy element is secured in place with a disc 66 that is fixed to the edge 64 or, as it is shown in Fig. 4, is fixed with a screw 68 to a transition element 48 which secures the cup 40 to the end of the rod 46. The transition element 48 is screwed onto the end of the rod 46, an outer thread on the rod 46 being in engagement with an upwards facing, axial, threaded hole in the transition element. The downwards facing end of the transition element 48 is designed as a bushing with both external and internal thread. The external thread receives a nut 50 that retains the cup 40 and the downwards facing edge 64 on the transition element, and the internal thread receives the screw 68. There may be created a sealing between the transition element 48 and the cup 40 with a not shown rubber disc.

When water rises in the drain 100, the buoyancy element 62 raises the cup 40 until the sharp edge 42 enters into a sealing engagement with the flexible sealing element 44. Thereby backflow or rising of water from the drain pipe is blocked. When the water again recedes in the drain pipe, the floating valve element falls down again until its movement is stopped by the stop 52 and there is again opened for outlet of water through the device.

Buoyancy from the buoyancy element 62 may be assistered by the force from an optional spring 60 which is positioned between the rod 46 and the bushing 36 and which acts on the rod 46 with an upwards force via the stop 52. At the bottom, the end of the spring abuts a radial face 36' that creates a transition between two sections of the through hole in the bushing 36 which have different diameters. The force from the spring may be such that the weight of the cup and the rod in a dry state, that is without the presence of water, presses the spring together, such that the valve element is open, but buoyancy from the buoyancy element in connection with the force from the spring can raise the cup to the closed position, when water rises in the floor drain. As an alternative the force from the spring can be such that the weight of the cup and the rod in a dry state, that is without the presence of water, can be carried by the spring which thus presses the cup up to the closed position, but that the cup under the influence of the weight of water that may be located above the cup in the lumen in the main element will be displaced to the open position and thus allow that the water exits into the drain. In the latter case the device has the advantage that the valve element closes, when water does not flow down into the floor drain and thereby sewer gas is blocked so that a trap is unnecessary. On the other hand, the sealing element 44 will be liable to exposure to contact with water, when water flows down into the drain.

The stop 52 that as stated is realized as an upside down cup in order to guide water which flows down through the drain away from the bushing 36, is shown in further detail in Fig. 7a and 7b, where the cup is shown in vertical cross sections from the side, at mutually right angles. The edge of the stop 52 can optionally be designed with a skirt 80 with two slots 82 that allow the floating valve element to assume its lower, open state, while the skirt 80 has en extent such that the cup in the closed position of the floating valve element can be turned in such a way that the edge of the skirt enters into engagement with two longitudinal webs 38 on the outer surface of the bushing 36 and thereby locks the floating valve element. In Fig. 5 there is shown a cross section along the line a - a of the bushing 36 with the webs 38. The said turning can be performed by an operator of the device who gribs the stop 52 on a bracket 84. In order to prevent that the stop unintented and by chance happens to lock the floating valve element in the closed state, and in order to bring about a predictable axial, closing bias force to the floating valve element in the locked state, a spring 58 is positioned between the disc 54 and the stop 52, and the stop 52 is additionally to a certain extent free to move axially on the rod 46, while it nevertheless is influenced by the spring forces. It is noted that the webs 38 are terminated at the top below the level of the upper end of the bushing 36 in order to prevent that water and dirt enters down into the hole in the bushing 36, as there is thereby created an axial overlap between the cylindrical surface of the stop and the bushing 36.

The device shown has special advantages therein that the sealing element 44 is facing downwards, and in the normal state where there is no rising of water in the drain, it does not get into contact with water, although this advantage is not necessarily realized if the optional spring 60 biases the cup 40 upwards to the closed position in the dry state. Thereby the risk is minimized that the sealing element 44 becomes dirty and that its function is thereby impaired. Contrariwise the sharp edge 42 is in contact with the water that flows down through the device, but partly the risk is small that dirt is deposited on the sharp edge 42, and partly the sharp edge 42 will be able to cut through possiblee dirt deposits and thereby in spite of these achieve a sealing engagement with the sealing element 44.

The dimensions of the device according to the first embodyment of the invention are optional, but must of course within a certain tolerance be adapted to the dimensions of the drain or drains wherein the device shall be used. The dimensions of the lumen in the main element 10, of the rod 46, and of the floating valve element 40 are preferably adapted such that the through flow of water in the open position of the device is impaired to a minimal degree. This is achieved if the area of the lumen in the main element and the area of the cup 40 each represent about 50 % of the area of the cross section of the drain, while there is thus approximately the same area for passage of water through the lumen and past the cup. Because of the necessary radial overlap between the edge 42 of the floating valve element and the sealing element 44, the effective area for through flow will necessarily be smaller than half the area of the cross section of the drain. The length of the rod 46 must further be adapted so that the area of the imaginary cylinder surface between the edge 42 of the cup and the sealing element 44 in the open position of the floating valve element likewise is at least half the area of the cross section of the drain. As the thickness of the material in the cup is assumed to be negligible with respect to the diameter of the drain, this teaching imposes that the diameter of the lumen in the main element should be about I/V2 or about 70 % of the diameter of the drain and the diameter of the cup 40 a little larger, and that the distance between the edge 42 of the cup and the sealing element 44 in the open position of the floating valve element preferably is at least V2/8 or about 18 % of the diameter of the drain. This last result is arrived at from the following consideration. When Ai designates the area of the lumen in the main element 10, A _c designates the area of the imaginary cylinder surface, r designates the radius of the edge 42 which is approximately the diameter of the drain divided by 2V2, and 1 designates the distance between the edge 42 of the cup and the sealing element 44 in the open position of the floating valve element, then:

A^ π r ² (1)

A _c = 2π r 1 (2)

Ai = A _c → 1 ~ r/2 (3)

The parts of the device according to the invention may be manufactured from metal or plastic, while the sealing elements 18, 22 and 44, however, as mentioned above are manufactured of a suitable natural or synthetic rubber material, a flexible polymer material such as polyuretan, or the like. Particularly the main element 10 and the spacers 20 and 24 can appropriately be manufactured by casting of metal such as stainless steel or brass, or plastic such as polycarbonate, whereas the cup 40 preferably may be manufactured by swaging of stainless steel plate. The rod 46 may be manufactured of corrosion resistant metal or of hard plastic such as polycarbonate.

When installing the device, the tightening tool is used to tighten the collar 26 on the main element 10 in such a way that the sealing elements are deformed and expand radially. As the first step the collar is tightened so much that the device can be introduced down into the drain with a fairly tight fit, that is such that the device can be introduced down into the drain without the use of excessive force, but nevertheless such that the device can remain in place under the influence of the friction between the sealing elements 18, 22 and the inner surface in the drain 100. Thereafter the collar 26 is tightened further to such an extent that the device remains firmly in place in the drain.

In Fig. 8 there is shown another embodyment of the present invention that substantially has common features with the first embodyment, and parts with the samme function in Fig. 4 and in Fig. 8 are therefore designated with the same reference numeral. The difference between the first and the second embodyments of the present invention consists therein that the second embodyment is further provided with a trap.

The function of a trap is achieved thereby that the cup 40 is realized with a sufficiently large depth so that an amount of water can be retained in the cup 40, and that the downwards facing funnel 32 that is sealingly connected with the main element 10 is extended such that it at the bottom edge of the funnel 32 is located below the level of the sharp edge 42 on the cup 40, also when the cup 40 is in its lowermost position where the floating valve element is open. Thereby the bottom edge of the funnel 32 is below the level of the water that is retained in the cup 40, and there is thereby established a trap so that there cannot pass sewer gas past the device.

Also in the second embodyment, buoyancy from the buoyancy element 62 can be assisted by the force from en optional spring 60 which is positioned between the rod 46 and the bushing 36 and which acts on the rod 46 with an upwards force. The force from the spring may be such that the weight of the cup and the rod in a dry state, that is without the presence of water, presses the spring together, such that the valve the element is open, but that buoyancy from the buoyancy element in connection with the force from the spring can raise the cup to the closed position when water rises in the floor drain. As an alternative the force from the spring can be such that the weight of the cup and the rod in a dry state, that is without the presence of water, can be carried by the spring, that is it presses the cup up to the closed position, but that the cup under influence of the weight of water that may be located in the cup will be displaced to the open position and thus allow the water to flow down into the drain. With special advantage, the force from the spring can be adapted such that the surface of the water in the cup will always be located right above the bottom edge of the funnel 32, until so much water has flown into the cup that it has been pressed to its lowermost position. Thereby the device has the advantage that the sealing element 44 will be able to avoid being exposed to contact with water when water flows down into the drain and out above the sharp edge 42 of the cup.

In the main the dimensions of the device according to the second embodyment can be identical to those for the device according to the first embodyment, while the axial dimensions of the funnel 32 and the cup 40 in the second embodyment of course are different. The radial dimensions of the cup and the lumen in the main element 10 are, however, preferably optimized and adapted to the limitations which the trap implies for the flow of water down into the drain. The ideal situation is achieved when the flow cross section in all places is the same and is approximately 1/3 of the area of the cross section of the drain. The diameter of the edge 42 of the cup is therefore preferably about V2/V3 or approximately 82 % of the diameter of the drain, and the diameter of the lumen in the main element is preferably about 1/V3 or approximately 58 % of the diameter of the drain. And in a similar manner as for the first embodyment, it can be calculated that the axial distance between the bottom of the cup and the bottom edge of the funnel 32 in the open position for the floating valve element preferably is at least 1Λ4-V3 or approximately 14 % of the diameter of the drain, whereas the distance between the sharp edge 42 and the sealing element 44 preferably is at least 1Λ4-V6 or approximately 10 % of the diameter of the drain. If it is assumed that the bottom edge of the funnel 32 in the open position for the floating valve element must be half way down into the depth of the cup 40 then the depth of the cup must be at least 1/2^3 or approximately 29 % of the diameter of the drain, whereas the funnel 32 must extend to about 1Λ4-V3 + 1Λ4-V6 or approximately 25 % of the diameter of the drain below the sealing element 44. As the device according to the invention is intended to be adapted to drains with diameters within a range of values, the dimensions of the device that are expressed as a percentage value of the diameter of the drain evidently cannot assume their ideal values for alle dimensions of the drain. The device will typically be adaptable to drains with diameters within an interval of about -0 % / +10 % of the diameter of the sealing elements 18, 22 in their not ekspanded state, and when dimensioning the device it will be natural to take as a starting point the middle of this interval. A certain deviation from the ideal dimensions is naturally possible and acceptable, while preferably the dimensions of alle embodyments of the invention can be stated as: diameter of the lumen in the main element 10: 50 - 80 % of the diameter of the sealing elements 18, 22 in the not expanded state; diameter of the sharp edge 42 on the cup: 50 - 90 % of the diameter of the sealing elements 18, 22 in the not expanded state; vertical distance between the sharp edge 42 on the cup and the sealing element 44 in the open position for the valve: 5 - 25 % of the diameter of the sealing elements 18, 22 in the not expanded state.

In Fig. 9 there is shown a further embodyment of the main element 10, the one sealing element 22, the spacer 24 and the collar 26. This further embodyment can optionally be used together with the first or the second embodyments which are respectively without and with a trap, and the complete one-way valve arrangement is therefore omitted in Fig. 9.

In the further embodyment there is only one sealing element 22 which is designed as a cylindrical object that is manufactured of flexible material with one rounded end edge and one radially cut end edge. The radially cut end edge is anchored in a groove between the cylinder surface of the main element 10 and a cylindrical edge 86 on the extension 14, as it is shown in Fig. 9. There is only one spacer 24 which has a relatively long and slightly curved, bevelled face that is suitable to shift the rounded end of the sealing element 22 totally out beyond the outermost diameter of the spacer 24. In order to prevent misalignment of the main element there is provided a plurality of at least three, angularly uniformly distributed spring brackets 88 which are anchored in the main element 10 below the extension 14. As it is shown to the right of the axis of the cylinder in Fig. 9, the spring brackets can expand radially and come into engagement with the surface in the floor drain, whereby the main element 10 is centered also in the plane wherein the spring elements are located. As it is shown to the left of the axis of the cylinder in Fig. 9, the spring brackets can, however, also be pressed together and radially inwards, whereby the device can be placed in a floor drain 100, the diameter of which only slightly exceeds the outermost diameter of the extension 14.

Those skilled in the prior art will recognize that the above described embodyments are only exemplary and are subject to modifications and changes that will all fall within the scope of the invention which is solely delimited by the appended claims.