EP1561869B1

EP1561869B1 - Water trap with return flow protection

Info

Publication number: EP1561869B1
Application number: EP05002107A
Authority: EP
Inventors: Hans Lohmann
Original assignee: Bluecher Metal AS
Current assignee: Bluecher Metal AS
Priority date: 2004-02-06
Filing date: 2005-02-02
Publication date: 2007-04-18
Anticipated expiration: 2025-02-02
Also published as: EP1561869A3; EP1561869A2; DE602005000886D1; DE602005000886T2; DK1561869T3; ATE360120T1

Abstract

The present invention concerns a water trap (1) with return flow protection, including a funnel (2) which is connected with a riser pipe (3), a bell (4) enclosing the riser pipe (3), and a valve (5) which is adapted for enclosing the riser pipe (3), and which is movable between a closed position where the valve (5) blocks for flow through the water trap (1), and an open position where the valve (5) allows a normal drain function, where the valve (5) includes valve seats (6, 7) on the riser pipe (3) and the bell (4), respectively, and a preferably replaceable valve body (8), where the valve body (8) is designed with a concave/convex cross-section.

Description

Scope of the Invention

The present invention concerns a water trap with return flow protection, including a funnel which is connected with a riser pipe, a bell enclosing the riser pipe, and a valve adapted for enclosing the riser pipe, and which is movable between a closed position where the valve blocks for flow through the water trap, and an open position where the valve allows a normal drain function, and where the valve includes valve seats on the riser pipe and the bell, respectively, and a preferably replaceable valve body.

Background of the Invention

In order to prevent smell nuisances from drain pipes from penetrating into a room, there is applied a water trap where the water forms a barrier preventing bad odour from penetrating up from the drain pipe.
The water trap may either be an integrated part of the drain, a part of the pipe installation or a loose unit that may be placed in the drain/drain pipe.
If the water trap is a loose unit, it is typically designed with a funnel which is connected with a riser pipe and a bell enclosing the riser pipe, so that the water is to pass down through the funnel and inside the riser pipe and subsequently up into the interspace along the outer side of the riser pipe and the bell.
As the upper edge of the bell is disposed above the lower edge of the riser pipe, there will be a certain amount of water which is always trapped in the water trap.
The drawback of such a water trap is that the water in the water trap may evaporate, and thus there will be free access for bad smell from the drain pipe penetrating up through the water trap.
In heavily loaded drain systems, where in case of e.g. flooding or strong downpours return flow of water from the drain pipe may occur, there is a risk of water damage in the room or of hygienic problems, as the return flushed water may contain bacteria.
In order to avoid problems with return flow of water from the drain pipe, HWS installations are provided with return flow protection that only allow water passing from the drain and down into the drain pipe.
The drawback of such an HWS installation is that it cannot block the smell nuisances, and therefor there is to be mounted both a water trap and a HWS fitting with return flow protection in order to ensure against both smell nuisances and return flow, implying that the costs for purchase and mounting the HWS installations are increased.
In order to solve the above problems, there is provided a water trap with an integrated return flow protection. In EP-B1-0 486 954 e.g. there is disclosed a water trap with return flow protection, where the water trap includes a funnel connected with a riser pipe and a bell enclosing the riser pipe, so that water may be retained in the bell and thereby shut off the smell nuisances from the drain.
In order to prevent return flow, the bell is connected to the funnel/riser pipe with a spring holding the bell clamped, so that the upper edge of the bell bears against a packing at the underside of the funnel, providing that water from the drain pipe cannot go back through the water trap.
When water is led down into the funnel/riser pipe, the weight of the water itself will, some time before the water reaches the funnel, be so great that it can overcome the spring force, and thereby the bell is lowered, and a gap appears between the bell and the outer side of the riser pipe through which the water is drained off.
However, there are several drawbacks by this embodiment of the disclosed water trap, as, for example:

There is used a spring which is activated every time water is led through the water trap, causing a risk of tiring the spring, whereby the bell is not held close against the packing at the underside of the funnel. If this happens, the water trap can only act as a water trap.
The weight of the water itself will only cause a small opening between the upper edge of the bell and the packing on the underside of the funnel, providing that it is necessary to design the water trap with large diameter in order to achieve a flow area between the upper edge of the bell and the packing at the underside of the funnel large enough for a water flow of at least 0.8 l/s which is required for certification of a water trap.
Due to the large diameter of the water trap and the movable bell, a special mounting connection with a large diameter and a dimensional transition down to the drain pipe is required.
There is a risk that dirt or the like becomes stuck in the spring connection and thereby prevents the spring from holding the bell up against the packing at the underside of the funnel.
The water trap is complicated to manufacture due to the spring and the movable bell.
The water trap may only be replaced by a water trap from the producer.

Some the above disadvantages are attempted solved by a water trap with a return flow protection as described in GB-A-2 134 940. Where the water trap in one of the disclosed embodiments includes a funnel which is connected with a riser pipe, a bell enclosing the riser pipe, and a valve adapted for enclosing the riser pipe, and which is movable between a closed position where the valve blocks for flow through the water trap, and an open position where the valve allows a normal drain function, and where the valve includes valve seats on the riser pipe and the bell, respectively, and a valve body.
This water trap, however, has other disadvantages, as e.g.:

The valve body is a flat body, entailing that a water pressure on the top side of the valve body may cause a unsuitable deflection of the valve body and thereby lead to leakages along the valve seats so that air or water from the drain pipe may go back through the water trap.
The valve body extends beyond the valve seat of the bell, entailing that a sudden return flow of liquid in the water trap, or an air pressure, gets hold of the projecting part of the valve body and lifts it off the valve seats, whereby there is a risk of liquid or air penetrating down through the water trap.

Due to the above drawbacks it is desirable to produce an improved water trap without these disadvantages.

Object of the Invention

It is therefore the purpose of the present invention to indicate a water trap with a secure return flow protection, which is technically simple to make, which has a compact shape, which is easy to maintain, and which is furthermore easy to mount/replace.
This is achieved with a water trap of the kind described in the preamble of claim 1, where the valve body is designed with a convex/concave cross-section.

Description of the Invention

In order to produce a water trap with integrated return flow protection, the water trap of the present invention is designed with a funnel connected with a riser pipe and a bell enclosing the riser pipe, whereby a water trap is formed, and where the return flow protection of the water trap is provided by the water trap furthermore including a valve.
The flow in the water trap is so that the liquid is led down into the funnel and down inside the riser pipe and up in the interspace between the outer side of the riser pipe and the bell.
In order to shut off the flow through the water trap, it is provided with a valve adapted for enclosing the riser pipe, and which is movable between a closed position where the valve blocks for flow through the water trap, and an open position where the valve allows a normal drain function.
When there is no liquid flow through the water trap, the valve will be in a closed position, so that the water trap is closed, and thereby smell nuisances from the drain pipe are prevented, irrespectively if there is liquid in the water trap or not.
When liquid is led down into the water trap, the pressure from the liquid will actuate the valve so that it moves from a closed position to an open position, whereby a normal drain function is allowed, and the liquid may flow out of the interspace between the outer side of the riser pipe and the bell.
When a return flow from the drain pipe occurs, the returning liquid will actuate the valve so that it is kept in the closed position, and thereby return flow up into the drain/room is prevented.
In a preferred embodiment of the invention, the valve includes valve seats on the riser pipe and the bell, respectively, and a preferably replaceable valve body, where the valve seat on the riser pipe may be one or more wholly or partially enclosing projections with a preferably flat top side, while the valve seat on the bell may be a bent edge part.
The self-weight of the valve body and possible air pressure in the drain pipe will provide that the valve body bears on the valve seats and thereby provide that the valve is in closed position.
The valve body has a width so that its edge parts bear on the valve body on the riser pipe and the valve seat on the bell, respectively, so that the valve body shuts off all through-flow in the water trap.
When liquid is conducted down into the water trap, the valve body will float upon the water surface between the outer side of riser pipe and the bell. In that way the water trap is moved from a closed position to an open position, so that the liquid may flow out of the interspace between the outer side of the riser pipe and the bell.
When a return flow from the drain pipe occurs, the pressure from returning liquid will press the valve body down against the valve seats so that it is kept in the closed position, and thereby return flow up into the room is prevented.
It is important that the valve body has a width which is adapted to the distance from the valve seats. This means that the valve body does not have projecting parts extending beyond the valve seats, by return flow reducing the risk of liquid getting hold of the edge parts of the valve body and thereby move the valve body up into an open position.
In order to ensure that the water trap is completely closed when the valve body lies on the valve seats, the valve body is designed with a convex/concave cross-section so that the top side of the valve body is convex and the underside is concave. This implies that the edge parts of the valve body bear on each their valve seat and curves upwards across the opening between the outer side of the riser pipe and the bell.
By the valve body having a convex/concave cross-section, the risk of leakages arising along the valve seats is reduced in case that a pressing force is applied on the top side of the valve body. This pressure force may be caused by air or water penetrating back from the drain pipe.
In a preferred embodiment of the invention, the valve seat on the riser pipe is disposed opposite the valve seat on the bell. This provides that the valve seat will lie approximately horizontally across the opening between the riser pipe and the bell, which is an advantage, as the valve seat thereby may fit tightly to the valve seats.
In an alternative embodiment of the invention, the valve seat on the riser pipe is disposed higher than the valve seat on the bell. This implies that the valve body will be inclined so that it slopes downwards from the riser pipe and out towards the bell, reducing the risk of a return flow getting hold of the edge of the valve body and forcing the valve body away from the valve seat on the bell, so that an opening arises and thereby a possibility of liquid through-flow in the water trap.
In order to avoid a sudden return flow of liquid in the water trap, or an air pressure, getting hold of a projecting part of the valve body and lifting it off the valve seats, whereby the risk of liquid or air penetrating through the water trap is increased, in a closed position the valve seat has an inner lip member bearing against the valve seat of the riser pipe and an outer lip part bearing against the valve seat of the bell.
As the outer lip part bears against the valve seat of the bell, it is not possible for a returning liquid or an air pressure to get hold of a projecting part of the valve seat and thereby lift it off the valve seats.
The inner and outer lip parts are more flexible that the rest of the valve body, entailing that the lip parts fit tightly to the valve seats. Due to the flexible lip parts, the valve body is more tolerant towards minor faults in production and a little dirt settling on the valve seats, and the effect of the return flow protection is therefore not reduced in case of minor production faults and a little dirt on the valve seats.
In order to make a compact water trap, the valve seat and the bell are connected with a projecting part of the bell, providing that the flow-through area between the bell and the riser pipe is increased so that it is possible to produce a compact water trap with a liquid flow of 0.8 l/s or more.
In an embodiment of the invention, the valve body is made of a polymer material, as e.g. a rubber material such as silicone rubber or a plastic material like TPE plastic, providing that the valve body is approximately soft so that the edge parts of the valve body fit tightly against the valve seats.
Alternatively, the valve body may be produced of another material, e.g. metal or ceramics, if very aggressive liquids are discharged which are destructive to the polymer material.
Valve bodies made of metal or ceramics may be provided with lips of a polymer material so that the valve body fits tightly down against the valve seats.
In order to ensure that the bell is permanently connected to funnel/riser pipe, the bell is connected to the riser pipe with a number of fittings that are preferably fastened to the riser pipe and subsequently screwed together with the bell.
This method of assembling riser pipe and bell implies that it is easy to maintain/clean the drain or replace the valve body when the bell is to be released, after which there is free access to the riser pipe and the valve body.
In order to achieve an airtight and water tight mounting of the water trap in a drain pipe, the funnel is provided with an annular packing which is disposed in an upper edge part. This packing furthermore provides for the water trap to be placed in a desired position during mounting, without falling down into the drain pipe while the water trap is fastened.
For fastening the water trap in a drain pipe, it includes a fastening unit connected to the funnel. This fastening unit is disposed so that it may be worked from the top of the water trap, so that it is either possible to press the water trap down into a drain pipe and subsequently to fasten the water trap, or reversely, to loosen the fastening unit and thereby release the water trap so that it may be taken up of the drain pipe for maintenance or cleaning.
In an embodiment of the invention, the fastening unit includes a clamping device with a number of radial arms which are adapted for engaging an inner side of a drain pipe. The clamping device furthermore includes a bolt screw which via a screw socket and a connecting member connects the clamping device to the funnel member.
This connecting member may be a plate having a cutout which is complementary to the internal shape of the funnel, so that the plate fits tightly to the funnel and is thereby easy to fasten, e.g. by spot welding or the like.
The screw socket may alternatively be connected to the bell and may be an upright part that in a lower end is fastened to the internal bottom of the bell.
If the fastening unit is centrally connected to the funnel, the radial arms have the same shape and length. The radial arms are adapted for engaging an inner side of a drain pipe so that they thereby hold the water trap in the desired position in the drain pipe.
In order to fasten the water trap in the drain pipe, the radial arms are longer than the distance from the centre of the clamping device to the point of abutment at the inner side of the drain pipe. The radial arms will therefore have a downwards curving shape in relation to the clamping device, providing that the fastening unit can be passed down together with the water trap.
The downwards curving shape implies that pressing down of the clamping device will force the radial arms downwards against an upper edge of the funnel, causing the pointed ends to be forced outwards and thereby extending beyond the upper edge of the funnel and engaging the inner side of the drain pipe so that the water trap is secured.
As pressing down of the clamping device is effected by the screw bolt being screwed down into the screw socket, it will not be possible to fasten the water trap in the drain pipe if the clamping device is incorrectly positioned.
In order to ensure that the water trap is secured in a fixed position in the drain pipe, the radial arms are designed with a number of pointed ends which will penetrate into the inner side of the drain pipe and thereby prevent displacing of the water trap by e.g. a strong return flow.
The pointed ends may be designed with different shapes, e.g. as a central pointed end on each radial arm, or as two pointed ends - one at each side edge of the radial arm. If there are more pointed ends, these may be separated by different forms of cutouts, e.g. a V-cutout or a concave cutout.
In a preferred embodiment of the invention, the water trap is made of metal, e.g. stainless steel, which has the advantage over plastic that it is more resistant to aggressive liquids or vermins, as e.g. rats, that gnaw through the water trap.

Short Description of the Drawing

The invention will now be explained more closely with reference to the accompanying drawing, where:

Fig. 1: shows a section of a water trap according to the invention;
Fig. 2: shows a detailed sectional view of a valve according to the invention;
Fig. 3: shows a section/perspective view of a water trap according to the invention; and
Fig. 4: shows a perspective view of a water trap according to the invention.

Detailed Description of the Invention

On Figs. 1 and 3 appears a water trap 1 that includes a funnel 2 which is connected to a riser pipe 3 and a bell 4 enclosing the riser pipe 3.
The water trap furthermore includes a valve 5 that includes a valve seat 6 on a riser pipe 3 and a valve seat 7 on a bell 4 and a valve body 8.
The valve body 8 is here shown in closed position, where the valve body 8 bears down against the valve seat 6 and the valve seat 7 in order to shut off flow through the drain 1.
The bell 4 is connected to the riser pipe 3 with a fitting 9.
The valve seat 6 on the riser pipe 3 is here shown disposed at the same level as the valve seat 7 on the bell 4.
The funnel 2 is provided with an annular packing 10 providing that the water trap 1 may be placed in a drain pipe (not shown) so that there is provided water and air tightness between a top side of the water trap 1 and an underside of the water trap 1.
A fastening unit 11 is connected to the funnel 2, including a clamping device 12 with radial arms 13.
The clamping device 12 is connected with a screw bolt 14 to a screw socket 15 which is fastened to a plate 16 fastened to the funnel 2 so that the screw socket 15 is disposed at the centre over the riser pipe 3.
At the moving of the screw bolt 14 down into the screw socket 15, the clamping device 12 will force the radial arms 13 down against an upper edge 2a of the funnel 2 and outwards.
On Fig. 2 is shown a detailed section of the valve 5 where it is seen that the valve body 8 has a cross-section with a convex top side 8a and a concave underside 8b, and where the concave underside 8b ends in lip parts 28a and 28b.
Lip parts 28a bear down against a valve seat 7, and lip parts 28b bear against an end 9a of fitting 9 which is connected to the riser pipe 3. In a section of the valve 5 where no fitting is provided, lip parts 28b will bear against the valve seat (not shown) on the riser pipe 3.
The valve seat 7 is shown formed with a projection 17 ensuring that the through-flow area between the bell 4 and the riser pipe 3 becomes larger, which implies a better flow through the water trap 1 and a possibility of producing a more compact water trap.
The fitting 9 is designed with a threaded hole 18 that allows a separatable assembling of the riser pipe 3 and the bell 4 by means of a bolt which is passed through a hole 19 in the bell 4 and into the threaded hole 18.
On Figs. 3 and 4 is shown how the radial arms 13 end in a pointed end 13a which is adapted for engaging an inner side of a drain pipe (not shown).
On Fig. 4 is shown how a water trap 1 looks like by mounting in a drain pipe (not shown).
As the length of the radial arms 13 is greater than the distance from the centre of a clamping device 12 and out to the internal side (not shown) of a drain pipe (not shown), the clamping device 12 will be with downwards directed radial arms 13.
This implies that a pressing down of the clamping device 12 will force the radial arms 13 down against the upper edge 2a of the funnel 2, entailing that the pointed ends 13a are forced outwards and thereby extend beyond the upper edge 2a of the funnel 2.
The screw bolt 20 is used for fastening the bell 4 to the fitting (not shown) that connects the bell 4 with the riser pipe (not shown).

Claims

A water trap with return flow protection, including a funnel (2) which is connected with a riser pipe (3), a bell (4) enclosing the riser pipe (3), and a valve (5) adapted for enclosing the riser pipe (3), and which is movable between a closed position where the valve (5) blocks for flow through the water trap (1), and an open position where the valve (5) allows a normal drain function, where the valve (5) includes valve seats (6, 7) on the riser pipe (3) and the bell (4), respectively, and a preferably replaceable valve body (8), characterised in that the valve body (8) is designed with a convex/concave cross-section, so that the top side of the valve body is convex and the underside is concave.
Water trap (1) according to claim 1, characterised in that the valve seat (6) on the riser pipe (3) is disposed opposite the valve seat (7) on the bell (4).
Water trap (1) according to any of claims 1-2, characterised in that the valve seat (6) on the riser pipe (3) is disposed higher than the valve seat (7) on the bell (4).
Water trap (1) according to any of claims 1-3, characterised in that the valve body (8) in a closed position has an inner lip member (28b) that abuts on the valve seat (6) of the riser pipe (3), and an outer lip member (28a) that abuts on the valve seat (7) of the bell (4).
Water trap (1) according to any of claims 1-4, characterised in that the valve seat (7) of the bell (4) and the bell (4) are connected with a projecting part (17) of the bell (4).
Water trap (1) according to any of claims 1-5, characterised in that the valve body (8) is made of a polymeric material.
Water trap (1) according to any of claims 1 -6, characterised in that the bell (4) is connected to the riser pipe (3) with a number of fittings (9).
Water trap (1) according to any of claims 1-7, characterised in that the funnel (2) is provided with an annular packing (10), and furthermore that the drain (1) is including a fastening unit (11) connected to the funnel (2).
Water trap (1) according to claim 8, characterised in that the fastening unit (11) includes a clamping device (12) with a number of radial arms (13) which are adapted for engaging an inner side of a drain pipe.
Water trap (1) according to any of claims 8-9, characterised in that the radial arms (13) are longer than the distance from the centre of the clamping device (12) to the point of abutment at the inner side of the drain pipe.
Water trap (1) according to claims 8-10, characterised in that the radial arms (13) are designed with a number of pointed ends (13a).