A liquid trap system; odour seal

Abstract

 Liquid trap system (100) which is adapted to allow a liquid to pass through the liquid trap system in a downstream direction while preventing gasses from passing through the liquid trap system in an upstream direction. The liquid trap system comprises at least two liquid traps (102',102'').

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a liquid trap system adapted to allow a liquid to pass through the liquid trap system in a downstream direction while preventing gasses from passing through the liquid trap system in an upstream direction.

DESCRIPTION OF THE INVENTION

[0002] The present invention relates to a liquid trap system adapted to allow a liquid to pass through the liquid trap system in a downstream direction while preventing gasses from passing through the liquid trap system in an upstream direction, wherein the liquid trap system comprises at least first and a second liquid trap.

[0003] The liquid trap system may comprise two or more liquid traps such as two, such as three, such as four, etc. Provision of two or more liquid traps allows for different use of the individual liquid traps. E.g. such that a first drain pipe is connected to a first liquid trap and a second drain pipe is connected to a second liquid trap, while a third liquid trap is arranged to function as a floor drain.

[0004] Moreover, the provision of a plurality of different liquid traps allows for a more compact design of the entire liquid trap system, as the total height of the system may be reduced. This is especially the case when a buoyancy member is arranged to close the liquid trap, as is described in further detail below.

[0005] In one embodiment, the liquid trap system forms part of a floor drain e.g. such that the upper surface of the liquid trap system is adapted to be positioned at the same level as the floor in which the liquid trap system is provided. A mesh for collecting larger particles e.g. hair may be provided on the upper surface of the floor drain. The liquid trap system may be used in connection with a drainage system in a kitchen e.g. a private or an industrial kitchen, a laboratory e.g. a research or test laboratory of a pharmaceutical company, a clinic e.g. a medical or dental clinic.

[0006] In one embodiment the first liquid trap is adapted to allow liquid to pass therethrough when the flow rate of the liquid flowing into the entire liquid trap system is above a first predetermined flow rate. Moreover in this embodiment, the second liquid trap may be adapted to allow liquid to pass therethrough when the flow rate of liquid flowing in the liquid trap system is above a second predetermined flow rate. In the embodiment, the second predetermined flow rate may be larger than the first predetermined flow rate.

[0007] By providing two liquid traps which are adapted to open at different flow rates, the flow rate through the individual liquid trap may be keep at a higher flow rate. This is desirable as low flow rates increases the risk of sedimentation and deposition of particles and grease.

[0008] As an example the first liquid trap may be adapted to open at the lowest possible flow rate - e.g. flow rates below 0.01 litres per second while the second liquid trap remains closed unless the flow rate exceeds 0.4 litres per second. The result is that while flow rate is below 0.4 litres per second, any liquid which flows into the liquid trap system is directed through the first liquid trap. It will be appreciated that if both liquid traps open at the same, the flow rate in each of the two liquid traps would be lower (i.e. 50 percent lower if the capacity of the two liquid traps is identical) as the total amount of water would be divided between both the liquid traps.

[0009] When in the example the flow rate exceeds 0.4 litres per second both the liquid traps will open and thus the flow rate in each of the two liquid traps will be reduced. However, if the dynamic flow of liquid through the second liquid trap cannot maintain the second liquid trap in its open state, the second liquid trap will close again.

[0010] In the above example, it is assumed that the capacity of the two liquid traps is identical, i.e. the maximum flow rate in the two liquid traps is the same for the two liquid traps. As is described below the system may be designed such that when the second liquid trap opens the flow rate in the first liquid traps remains at its maximum, whereby the flow of liquid in the second liquid trap will start at a flow rate lower than 50 percent of the flow rate of all liquid flowing into the entire liquid trap system.

[0011] It will be appreciated that in systems comprising more that two liquid traps e.g. three liquid traps, each of different liquid traps may be adapted to allow liquid to pass at different flow rates of liquid flowing into the entire liquid trap system.

[0012] In one embodiment, the liquid passes through the first liquid trap while being prevented form passing through the second liquid trap, if a flow rate of liquid flowing into the entire liquid trap system is below a predetermined threshold. In the same embodiment, the liquid passes through both liquid traps if said flow rate is above the predetermined threshold, such that a first part of the liquid passes through the first liquid trap while a second part of the liquid passes through the second liquid trap.

[0013] In one embodiment, at least one of the first and the second liquid traps comprises a buoyancy system, each of which defines a well with an inlet and an outlet, and a buoyancy member is provided in the well such that when a predetermined amount of liquid is accommodated in the well, the inlet of the well is closed by the buoyancy member due to the buoyancy thereof, and such that the buoyancy member is forced away from the inlet by gravity when a predetermined amount of liquid is provided above the buoyancy member.

[0014] One advantage of providing a buoyancy member is that the systems ability to prevent backflow of liquid in an upstream direction is improved. The reason being that an increasing pressure causes the seal between the inlet and the buoyancy member to be improved, as the two are forced towards each other with an even larger force. The effect of the improved seal is that the liquid trap system may be able to withstand a pressure corresponding to a water column of 5 meters, such as 8 meters, such as 10 meters, such as 12 meters, such as 15 meters, such as 20 meters, such as 30 meters.

[0015] By providing a liquid trap system with an improved ability to withstand high pressure downstream relative to the liquid traps, it is prevented that odors, viruses and bacteria flows backwards in the system. Moreover, dangerous gasses in a sewer system are prevented escaping into houses, kitchens, bathrooms, clinics, etc. through the liquid trap system due to back flow therethrough. Accordingly, the present invention reduces the risk of terrorist attacks with gasses through the sewer system.

[0016] In one embodiment, the inlet is defined by an annular lip which defines a circular opening.

[0017] It will be appreciated that the inner diameter of opening must be smaller than the outer diameter of the buoyancy member, in order for the sealing effect to be achieved. If the diameter of the inlet is larger than the diameter of the buoyancy member, the latter may flow through the inlet, e.g. if the downstream pressure increases. The annular lip may comprise an elastic material such as natural or synthetic rubber.

[0018] Alternatively, or as a supplement, at least one of the first and second liquid traps comprises an elastic system, each of which defines a well with an inlet and an outlet, and a blocking member arranged to be biased into contact with the inlet by means of an elastic member so as to close the inlet. In the embodiment, the blocking member may be forced away from the inlet by gravity when a predetermined amount of liquid is provided above the blocking member.

[0019] As is the case with the buoyancy member, the blocking member will improve the ability of the liquid trap system to resist/prevent backflow of liquid in the upstream direction as an increased pressure downstream relative to the liquid trap system will cause the blocking member and the inlet to be forced towards each other with an even larger force.

[0020] It will be appreciated that just as the buoyancy of the buoyancy members is determining for the flow rate at which the liquid trap opens, the spring constant of the resilient element determined the flow rate at which the liquid trap opens.

[0021] In one embodiment, each of the first and second liquid traps comprises an elastic system. In the embodiment, the spring constant of resilient element of the second liquid trap is larger than the spring constant of the resilient element of the first liquid trap. Accordingly, the first and second liquid traps opens at different flow rates.

[0022] It will be appreciated that the principle of the buoyancy member and the elastic member may be combined in any way. E.g. one of the liquid traps may comprise a buoyancy member while another of the liquid traps (in the same system) comprises an elastic member. Moreover, each of the liquid traps may comprise both a buoyancy member and an elastic member. Thus in one embodiment, each the first and second liquid traps comprises a buoyancy system and wherein the buoyancy of the buoyancy member of the first liquid trap is lower than the buoyancy of the buoyancy member of the second liquid trap.

[0023] It will be appreciated that when the liquid trap system comprises two buoyancy members with different buoyancy, the liquid trap with the buoyancy member having the lowest buoyancy will open before the other liquid trap (in which the buoyancy of the buoyancy member is larger). The difference in buoyancy may be achieved by providing buoyancy members of different volumes e.g. the volume of the first buoyancy member may be smaller than the volume of the second buoyancy member.

[0024] Alternatively, the two buoyancy members may have identical volumes while the weights of the two buoyancy members are not identical. The latter may be achieved by providing the two elements in different materials or by inserting a small weight in one of the buoyancy members, such a weight could be a liquid with a density which is higher than the density of the liquid passing through the liquid trap system.

[0025] In one embodiment, the first and second liquid traps are arranged such that liquid flowing into the liquid trap system initially enters the first liquid trap and if the flow rate is above a predetermined flow rate, a first part of the liquid flow through the first liquid trap, while a second part of the liquid flows into the second liquid trap and further therethrough.

[0026] Again the effect is that the flow rate of liquid flowing through the respective liquid trap is higher than if both liquid traps were open at the same time. One advantage of the increased flow rate is that sedimentation and depositing of material may be reduced or even eliminated.

[0027] The liquid trap system may be designed such that the individual liquid traps may be used not only for draining a floor, but also for connecting a drain pips thereto. Accordingly, in one embodiment, the inlet of at least one of the first and second liquid traps is adapted by be fluidly connected to the outlet of a drain pipe. The drain pipe may be a drain pipe of a sink, a bath tub, a dish washing machine, a washing machine or any other device which must be connected to a drain.

[0028] It will be appreciated that the liquid trap system may take any form. As an example the liquid trap system may form part of a drain pipe e.g. such that it serves the function of connecting two drain pipes.

[0029] In one embodiment, the buoyancy member defines an outer surface which is adapted to prevent or reduce the depositing of waste material. It will be appreciated that when deposition of material is prevented the risk of the clogging of the liquid trap system is reduced or even eliminated.

[0030] In one embodiment the outer surface of the buoyancy member defines a plurality of indentations. The effect of the indentations is that in use thy will cause the buoyancy member to rotate when liquid flows through the liquid trap. The rotation will cause particles or grease deposited on the outer surface of the ball to be removed as the annular lip defining the opening of the liquid trap will scrape such material away. The provision of indentations/dimples in the buoyancy member results in a delay in the separation of the boundary layer of water from the ball. The effect is that the liquid tends to "stick" to the buoyancy member 112, and thus reduces the risk of other material being deposited on the surface of the buoyancy member.

[0031] In one embodiment, the buoyancy member on its outer surface is coated with a material which prevents depositing of material thereon. An example of such a material is polytetrafluoroetylen (PTFE) e.g. Teflon.

[0032] It will be appreciated that any surface of the liquid trap system may be coated with the material (e.g. PTFE) so as to prevent deposition of material on any of its surfaces.

BRIEF DESCRIPTION OF THE FIGURES

[0033] The invention will now be described in further detail with reference to the figures in which:

Fig. 1 discloses a liquid trap system according to the present invention,

Fig. 2 discloses flow of water into the liquid trap system,

Fig. 3 discloses prevention of back flow in the liquid trap system,

Fig. 4 discloses a drain pipe connected to the liquid trap system according to the present invention,

Figs. 5-6 disclose use of the liquid trap system when a drain pipe is connected to the liquid trap system,

Fig. 7 discloses an alternative arrangement of the outlet, and

Fig. 8 discloses the buoyancy member according an embodiment of the invention.

DETAILED DESCRIPTION OF THE FIGURES

[0034] Fig. 1 discloses a liquid trap system 100 in the form of a floor drain. However, as previously described, the liquid trap system may take any other form e.g. the liquid trap system may form part of a waste pipe. The liquid trap system 100 defines a first liquid trap 102' and a second liquid trap 102". Both liquid traps 102',102" are provided below the upper surface 104 of the liquid trap system 100 which is designed such that when the liquid trap system 100 is mounted in the floor, the upper surface 104 is at the same level as the upper surface of the floor (not visible in the figure). The upper surface 104 encircles the main inlet 101 of the liquid trap system 100. Moreover, the system 100 defines a main outlet 103.

[0035] The liquid traps are retained relative to the liquid trap system 100 by means of a retaining ring 107, which is permanently or detachably fastened to the liquid trap system 100. In embodiments in which the retaining ring 107 detachably attached to the liquid trap system 100, this detachably attachment may be achieved by means of a threaded or a snap-lock connection. It will be appreciated that the ability to withstand back pressure (back flow of water) is partly determined by said (permanently or detachably) fastening of the retaining ring 107.

[0036] Each of the liquid traps 102',102" defines a well 106',106" with an inlet 108',108" and an outlet 110',110". In each well 106, an buoyancy member 112',112" is provided which - when a liquid (e.g. waste water) is provided in the liquid trap 102',102" - is forced into contact with an annular lip 114',114". Each annular lip 114',114" defines a passage with an inner diameter. The inner diameter of the passage is smaller than the diameter of the respective buoyancy member 112',112", and thus the buoyancy of the buoyancy member 112',112" causes the buoyancy member 112 to be forced into contact with the annular lip 114',114", so as to close the respective liquid trap 102',102".

[0037] The well 106',106" forms part of the water trap 102',102" whereby water (or any other liquid) entering the well 106',106" is accommodated in the well 106',106" such that gasses are prevented from passing in an upstream direction inside the liquid trap 102',102". Thus, odours and bacteria located downstream relative to the liquid trap 102',102" are prevented from passing through the liquid trap 102',102".

[0038] When water enters the well 106',106", the water will flow over the rim 116',116" defining the outlet 110 of the respective well 106',106". The liquid trap effect is in part achieved by means of a wall 118',118" which prevents the gasses from passing in the upstream direction while allowing the liquid to pass in the downstream direction and in part by means of the buoyancy member 112',112".

[0039] It will be appreciated that the vertical position of the rim 116',116" determines the vertical position of the upper surface (indicated by dotted line 117) of the liquid contained tin the wells 106',106". Thus, the relative position of the annular lip 114',114" and the rim 116',116" determines how close the buoyancy member 112',112" can be to the upper surface of the liquid. In other words, the aforementioned relative position determined the minimum distance which the buoyancy member 112',112" is submerged under the water level, and thus the force exerted by the buoyancy member 112',112" on the annular lip 114',114". As this force is demining for the ability of the water traps to prevent back flow i.e. flow of water in an upstream direction, it may is some embodiments be desirable to position the annular lip 114',114" as far as possible below the rim 116',116", while still allowing the buoyancy member 112',112" to move during downstream flow of water in the system. However, it will also be appreciated that the larger the force exerted by the buoyancy member 112',112" on the annular lip 114',114" is the more liquid must be provided above the buoyancy member 112',112" for it to be forced downwards such that the liquid trap opens and allows flow of water in the downstream direction.

[0040] In one embodiment of the invention, the difference is at least 3 millimetres, such as at least 5 millimetres, such as at least 10 millimetres, such as at least 15 millimetres, such as at least 20 millimetres.

[0041] In one embodiment of the invention the difference is chosen such that the water traps may prevent backflow of water, even if the water pressure in the liquid system downstream from the liquid traps is at least 0.5 bar, such as at least 1 bar, such as at least 1.5 bar, such as at least 2 bar, such as at least 2.5 bar, such as at least 3.0 bar, such as at least 3.5 bar or 4 bar.

[0042] The wall 118',118" terminates in a lower surface 120',120" which when liquid is provided in the well is covered with liquid. It will be appreciated that the distance from the lower surface 120',120" of the wall 118',118" to the upper surface (the water/liquid level) of the liquid accommodated in the well (not shown) also is a determining factor in relation to the pressure the liquid trap system 100 may be subjected to in the downstream direction while still preventing odours and bacteria from flowing in the upstream direction.

[0043] Fig. 2 discloses the use of the liquid trap system 100. In order to simplify the figures a many of the reference numbers present in Fig. 1 have not been indicated. However, as the two figures are identical (except from the arrows indicating flow), the reference numbers of fig. 1 also applies to Fig. 1.

[0044] As shown in Fig. 2, the first and second liquid traps 102',102" are arranged such with respect to each other that liquid flowing into the liquid trap system 100 will initially flow into the well 106' of the first liquid trap 102' (indicated by arrows 121). This will cause the liquid to be collected in the inlet area 122' of the first well 106'. When the weight of the liquid exceeds a predetermined threshold, the liquid will cause the buoyancy member 112' to be forced downwards and thus out of engagement with the annular lip 114'. This will cause the first liquid trap 102' to open whereby the liquid will flow though the first liquid trap 102'. If the water flow precedes the flow capacity of the first liquid trap 102, the liquid contained in the first inlet area 122' will flow over the separation wall 124, which separates the first inlet area 122' of the first liquid trap 102' and the second inlet area 122" of the second liquid trap 102". This overflow of liquid is indicated by arrow 126. Similarly to the first liquid trap 102', the second liquid trap 102" will open when the weight of the liquid contained in the second inlet area 122" exceeds a predetermined threshold. In this situation the liquid will flow not only through the first liquid trap 102', but also through the second liquid trap 102".

[0045] One advantage of providing two liquid traps 102',102" is that the overall height of the system may smaller than conventional systems (with the same ability to withstand a high pressure downstream the liquid traps).

[0046] Fig. 3 illustrates that a situation with increasing pressure (indicated by arrows 125) in the area downstream relative to the liquid trap system 100. However, the provision of the buoyancy members 112 causes the liquid trap system 100, as the buoyancy of the buoyancy members 112 causes these members 112 to abut the annular lip 114 such that backflow of water is prevented. The buoyancy of the buoyancy members 112 is indicated by arrows 127

[0047] In Figs. 4-6 a drain pipe 128 has been connected to the second liquid trap 102" by means of a rubber manifold 130, which in the embodiment of the figures is designed such that that it defines a wide part 132 and a narrow part 134. The inner diameter of the wide part corresponds to the outer diameter of the drain pipe 128 such that the drain pipe 128 may be inserted into the wide part 132 whereby a seal is defined between the drain pipe 128 and the rubber manifold 130. Similarly, the outer diameter of the narrow part 134 corresponds to the inner diameter of the inlet area 122" of the second liquid trap 102", thus allowing the rubber manifold 130 to be inserted into the inlet area 122" whereby a seal is defined between the rubber manifold 130 and the inlet area 122". Due to the seals, overflow of water from the first inlet area 122' to the second inlet area 122" is prevented.

[0048] As the drain pipe 128 is directly connected to a liquid trap, bacteria located downstream the liquid trap system 100 is prevented from passing in the upstream direction and into the drain pipe 128.

[0049] The first liquid trap 102' of the liquid trap system 100 of Figs. 4-6 serves as a floor drain and thus liquid (e.g. water) provided on the floor will flow into the first liquid trap 102' as is indicated by arrow 121, and continue further out of the main outlet 103 of the liquid trap system 100. This flow is indicated by arrows 125. The buoyancy of the buoyancy prevents the inflowing water from entering the drain pipe.

[0050] Fig. 7 discloses yet another embodiment of the invention in which the main outlet is provided in the bottom of the liquid trap system 100.

[0051] Fig. 8 discloses a buoyancy member 112 which defines an outer surface adapted to prevent or reduce the depositing of waste material due to the provision of indentations 136. In use the indentations 136 will cause the buoyancy member 112 to rotate relative to the annular lip 114 whereby any waste deposited on the outer surface is scraped away by the annular lip 114.

Claims

1. A liquid trap system (100) adapted to allow a liquid to pass through the liquid trap system in a downstream direction while preventing gasses from passing through the liquid trap system in an upstream direction, wherein the liquid trap system comprises at least first and a second liquid trap (102,104).

2. A liquid trap system according to any of the preceding claims, wherein the first liquid trap is adapted to allow liquid to pass therethrough when the flow rate of the liquid flowing into the entire liquid trap system is above a first predetermined flow rate, and wherein the second liquid trap is adapted to allow liquid to pass therethrough when the flow rate of liquid flowing in the liquid trap system is above a second predetermined flow rate, the second predetermined flow rate being larger than the first predetermined flow rate.

3. A liquid trap system according to any of the preceding claims, wherein at least one of the first and the second liquid traps comprises a buoyancy system, each of which defines a well with an inlet and an outlet, and a buoyancy member is provided in the well such that when a predetermined amount of liquid is accommodated in the well, the inlet of the well is closed by the buoyancy member due to the buoyancy thereof, and such that the buoyancy member is forced away from the inlet by gravity when a predetermined amount of liquid is provided above the buoyancy member.

4. A liquid trap system according to any of the preceding claims, wherein at least one of the first and second liquid traps comprises an elastic system, each of which defines a well with an inlet and an outlet, and a blocking member arranged to be biased into contact with the inlet by means of an elastic member so as to close the inlet, and wherein the blocking member is forced away from the inlet by gravity when a predetermined amount of liquid is provided above the blocking member.

5. A liquid trap system according to claim 3, wherein each of the first and second liquid traps comprises either of a buoyancy system or a resilient system.

6. A liquid trap system according to any of claims 5, wherein each the first and second liquid traps comprises a buoyancy system and wherein the buoyancy of the buoyancy member of the first liquid trap is lower than the buoyancy of the buoyancy member of the second liquid trap.

7. A liquid trap system according to any of claims 5 or 6, wherein the volume of the first buoyancy member is smaller than the volume of the second buoyancy member.

8. A liquid trap system according to claim 5, wherein each of the first and second liquid traps comprises an elastic system and wherein resilient element of the first and second liquid traps have a spring constant, the spring constant of resilient element of the second liquid trap being larger than the spring constant of the resilient element of the first liquid trap.

9. A liquid trap system according to any of the preceding claims, wherein the first and second liquid traps are arranged such that liquid flowing into the liquid trap system initially enters the first liquid trap and if the flow rate is above a predetermined flow rate, a first part of the liquid flow through the first liquid trap, while a second part of the liquid flows into the second liquid trap and further therethrough.

10. A liquid trap system according to any of the preceding claims, wherein the inlet of at least one of the first and second liquid traps is adapted by be fluidly connected to the outlet of a drain pipe.

11. A liquid trap system according to any of the preceding claims, wherein the buoyancy member defines an outer surface which is adapted to prevent or reduce the depositing of waste material.

12. A liquid trap system according to claim 11, wherein the outer surface of the buoyancy member defines a plurality of indentations.

13. A liquid trap system according to claim 11 or 12, wherein the buoyancy member on its outer surface is coated with a material which prevents depositing of material theron.

14. A liquid trap system according to claim 13, wherein the material comprises polytetrafluoroetylen (PTFE).

Amended claims

Amended claims in accordance with Rule 137(2) EPC.

1. A liquid trap system (100) adapted to allow a liquid to pass through the liquid trap system (100) in a downstream direction while preventing gasses from passing through the liquid trap system (100) in an upstream direction, wherein the liquid trap system (100) comprises at least first and a second liquid trap (102',102")
characterized in that
the first liquid trap (102') is adapted to allow liquid to pass therethrough when the flow rate of the liquid flowing into the entire liquid trap system (100) is above a first predetermined flow rate, and wherein the second liquid trap (102') is adapted to allow liquid to pass therethrough when the flow rate of liquid flowing in the liquid trap system (100) is above a second predetermined flow rate, the second predetermined flow rate being larger than the first predetermined flow rate.

2. A liquid trap system according to any of the preceding claims, wherein at least one of the first and the second liquid traps (102',102") comprises a buoyancy system, each of which defines a well (106',106") with an inlet (108',108") and an outlet (110',110"), and a buoyancy member (112',112") is provided in the well such that when a predetermined amount of liquid is accommodated in the well (106',106"), the inlet (108',108") of the well (106',106") is closed by the buoyancy member (112',112") due to the buoyancy thereof, and such that the buoyancy member (112',112") is forced away from the inlet (108',108") by gravity when a predetermined amount of liquid is provided above the buoyancy member (112',112") .

3. A liquid trap system according to any of the preceding claims, wherein at least one of the first and second liquid traps (102',102") comprises an elastic system, each of which defines a well (106',106") with an inlet (108',108") and an outlet (110',110"), and a blocking member arranged to be biased into contact with the inlet (108',108") by means of an elastic member so as to close the inlet (108',108"), and wherein the blocking member is forced away from the inlet (108',108") by gravity when a predetermined amount of liquid is provided above the blocking member.

4. A liquid trap system according to claim 2, wherein each of the first and second liquid traps (102',102") comprises either of a buoyancy system or a resilient system.

5. A liquid trap system according to any of claims 4, wherein each the first and second liquid traps (102',102") comprises a buoyancy system and wherein the buoyancy of the buoyancy member (112') of the first liquid trap (102') is lower than the buoyancy of the buoyancy member (112") of the second liquid trap (102').

6. A liquid trap system according to any of claims 4 or 5, wherein the volume of the first buoyancy member (112') is smaller than the volume of the second buoyancy member (112").

7. A liquid trap system according to claim 4, wherein each of the first and second liquid traps (102',102") comprises an elastic system and wherein resilient element of the first and second liquid traps (102',102") have a spring constant, the spring constant of resilient element of the second liquid trap (102') being larger than the spring constant of the resilient element of the first liquid trap (102').

8. A liquid trap system according to any of the preceding claims, wherein the first and second liquid traps (102',102") are arranged such that liquid flowing into the liquid trap system (100) initially enters the first liquid trap (102') and if the flow rate is above a predetermined flow rate, a first part of the liquid flow through the first liquid trap (102'), while a second part of the liquid flows into the second liquid trap (102') and further therethrough.

9. A liquid trap system according to any of the preceding claims, wherein the inlet (108',108") of at least one of the first and second liquid traps (102',102") is adapted by be fluidly connected to the outlet (110',110") of a drain pipe.

10. A liquid trap system according to any of the preceding claims, wherein the buoyancy member (112',112") defines an outer surface which is adapted to prevent or reduce the depositing of waste material.

11. A liquid trap system according to claim 10, wherein the outer surface of the buoyancy member (112',112") defines a plurality of indentations (136).

12. A liquid trap system according to claim 10 or 11, wherein the buoyancy member (112',112") on its outer surface is coated with a material which prevents depositing of material thereon.

13. A liquid trap system according to claim 12, wherein the material comprises polytetrafluoroetylen (PTFE).

Drawing