EP2904163B1

EP2904163B1 - A duct element, a drain pipe emptying system and method for temporarily disconnecting an outlet pipe of a building from a sewer main

Info

Publication number: EP2904163B1
Application number: EP13777157.2A
Authority: EP
Inventors: Hendrik Cornelis VAN RAVENHORST
Original assignee: Willemsen Gaby
Current assignee: Willemsen Gaby
Priority date: 2012-10-08
Filing date: 2013-10-07
Publication date: 2018-04-04
Anticipated expiration: 2033-10-07
Also published as: NL2009587C2; EP2904163A1; WO2014058310A1

Description

TECHNICAL FIELD

The invention relates to a duct element, a drain pipe emptying system and method for temporarily disconnecting an outlet pipe of a building from a sewer main.

BACKGROUND ART

There are regulations that when work is done a sewage systems, measure should be taken that sewage water cannot be discharged in the soil. Until recently, when a sewage system is being renovated, the drainpipe coming from a building and going to a sewer main is truncated and the sewage water and the substances present therein flows into the soil. Said substances contain bacteria and other germs. To prevent infection of diseases, direct contact with people should be avoided. In case the sewer main has to be replaced, the sewage water coming from a building will be discharged for many days into the soil, resulting in contamination of groundwater. Next to contamination, there is a risk of infection with diseases or allergies and odour nuisance, which may remain for a long time even after the drainpipe is covered with soil.
WO2011/010915A1 discloses a collecting watertight bottom section to be placed under the drainpipe. The watertight bottom section functions as a collecting container after a clogged drainpipe has been drilled through, into which the contaminated drainage water running from the drainpipe can flow without contaminating the surrounding area or the soil. The soil remains dry, it is not contaminated and the environment is thus burdened less. A top section can be place on top of the collecting section, and the contaminated drainage water can be pumped from the collecting section into a temporary or non-temporary facility.
The collecting watertight bottom section and top section could be used for temporarily disconnecting an outlet pipe of a building from a sewer main. However, a relative large and deep hole to place the bottom section under the drainpipe. Furthermore, the bottom section should be installed stable with respect to the existing drainpipe to provide a watertight coupling. Moreover, if the soil is squashy, the bottom section and top section could sink in the soil due to its weight inclusive the collected sewage water. This could result in damage of the drainpipe which has to carry part of the weight. After the sewer main could be used again, the drainpipe which is partially removed somewhere in the bottom section, has to be repaired. At this moment, a person has to work in the bottom section and there is a risk that he will become in contact with the sewerage water in the bottom section. After the pipe has been repaired, the bottom section has to be removed, which could be time consuming.
US2012/0097263A1 , which is regarded as closest prior art for claims 1, 12, 13 and 14, discloses a method and apparatus for isolating a section of a sewer line. A chamber is provided that extends into the ground and intersects a sewer pipe. Thereafter, the fluid in the sewer pipe is exposed to an interior of the chamber and a dam is placed in the chamber to isolate an upstream portion ot the chamber from a downstream portion. As fluid collects in the upstream side of the chamber, at least one pump is used to control the fluid level in the upstream portion by transferring the fluid from the chamber to a predetermined remote location.

SUMMARY OF INVENTION

It is an object of the invention to provide a duct element suitable for temporarily disconnecting an outlet pipe of a building from a sewer main, to obviate at least one of the disadvantageous, described above.
According to a first aspect of the invention, there is provided a duct element having the features of claim 1. Advantageous embodiments and further ways of carrying out the invention may be attained by the measures mentioned in the dependent claims.
A duct element for use in a sewage system according to the invention comprises an inlet structure, an outlet structure and an intermediate structure. The inlet structure is configured to couple the duct element with a first drainpipe of the sewage system. The outlet structure is configured to couple the duct element with a second drainpipe of a sewage system. The intermediate structure forms a duct between the inlet structure and the outlet structure, wherein the intermediate structure comprises an opening to provide access to the inlet structure and outlet structure. When the opening and outlet structure are closed watertight by sealing elements the intermediate structure comprises a space which enables the duct element to collect a minimum amount of sewage before sewage is collected in the inlet structure. The minimum amount enables a pumping device to drain sewage from the space and the sewage collected in the inlet structure. The space comprises a flat bottom in a plane. The inlet structure forms a duct having an upper side which in longitudinal direction of the duct is essentially parallel to the plane of the flat bottom
The invention is based on the concept that the possibility to lose sewerage from the sewer system is reduced significantly when the outlet pipe of a building is permanently provided with a construction which could be used to store a minimum amount of sewerage such that a pump could fully discharge the drainpipe upstream the structure, i.e. in the direction of the sewage source, when said drainpipe is at least partially filled with sewerage water. In this way, there is no need to truncate the drainpipe or to make holes in the drainpipe, which have to be repaired after the sewer main could be used again. Normally, a drainpipe runs gradually downward so that no sewer water is collected in the pipe. A pump needs a minimum amount of water or water height to discharge the water present in a space. If a pipe could not be fully discharged, waste will accumulate in the pipe. The duct element described above provides a structure which enables a pump to empty a drainpipe upstream the duct element. Even when the drainpipe is at least half filled with sewerage water a flow could be generated which completely discharges the drainpipe upstream the duct element. In this way, despite that sewerage is temporarily collected in the drainpipe, no waste is accumulated at the bottom of the drainpipe. The drainpipe upstream the duct element could be used as buffer to collect sewage water. The buffering capacity is a multitude of the buffering capacity of the intermediate structure. As a result of this, the number of times the pump has to be switch on could be relatively low. The terms "upstream" and "downstream" relate to an arrangement of items or features relative to the propagation of fluid through the system.. It is obvious that in the context of the present application "watertight" closed also means that the opening is air-tight sealed.
It should be noted that EP1925756A1 discloses a peephole. The peephole does not comprise the necessary space between the inlet structure and the outlet structure to collect the minimum amount of sewage to enable a pump to fully discharge the drainpipe upstream the structure. EP1260641A1 discloses a structure which is suitable to collect the minimum amount of waste water, whereby waste water will accumulate to a level which is below the flow profile of the upstream drainpipe.
Another advantage of the duct element is that it could be used to replace the commonly known access pipe part. An access pipe part enables one to inspect the drainpipe and could be used to unclog or clean the drainpipe.
In an embodiment, the inlet structure of the duct element has a flow profile and a substantially flat wall of the intermediate structure forming a bottom of the space is at least 5 cm lowered with respect to the flow profile of the inlet structure. The minimum depth of the bottom of the space relative to the flow profile of the inlet structure depends on the type of pump used to discharge the space. If there is not enough depth, the pump will suck air before the inlet structure is emptied, as a result of this the pump loses its pumping capacity and consequently solid particles in the sewage water could accumulate at the bottom of the upstream drainpipe. It has been found that for a commercially available submersible pump with crushing system a depth of 8 cm is sufficient to discharge the inlet structure and drainpipe coupled to the inlet structure.
In an embodiment, the outlet structure of the duct element comprises a flow profile which is aligned with the profile of the inlet structure. The intermediate structure is further configured to receive a detachable flow profile part which profile part provides the duct element a continuous flow profile from the inlet structure to the outlet structure. This feature enables us to reduce the height difference between the inlet structure and the outlet structure. In this way, the decline of the outlet pipe could be greater than when the flow profile of the outlet part and bottom of the intermediate structure be at the same level. This reduces the chance of clogging in the pipes coupled to the duct element. Furthermore, the detachable flow profile reduces the risk of waste accumulating in the duct element when the sewerage from the building could be drained to the sewer main.
In an embodiment, the inlet structure and the outlet structure have a duct diameter and the duct of the intermediate structure has a length which is longer than the duct diameter of the inlet structure. This features provides a space which is sufficient large to collect waste water and to pump the waste water out of the intermediate structure. In advantageous embodiments, the inlet structure and the outlet structure have a duct diameter in the range 100 - 250 mm.
In an embodiment, the minimum amount of sewage has a depth which is sufficient for a submersible pump to operate.
According to a second aspect of the invention, there is provided a drain pipe emptying system for temporarily disconnecting an outlet pipe of a building from a sewer main. The system comprising a duct element according to the first aspect and a top section which closes watertight the opening of the intermediate structure of the duct element. The top section comprises a submersible pump, one or more sensor generating signals enabling a controller to control the submersible pump and a coupling structure to couple a discharge duct to the submersible pump. The system provides a compact and easy to install system to disconnect an outlet pipe of a building temporarily from a sewer main. An advantage of a detachable top section is that the top section could be reused. After detaching the top section, the opening of the duct element could easily be closed with a lid.
In an embodiment of the system, the top section further comprises a valve construction configured to prevent sewer in the intermediate structure to enter the outlet structure. This feature provides a system which enables a person to discharge most of the waste water in the space in the system prior to detaching the top section. This could just be done by flowing clean water through the outlet pipe of the building. This reduces the possibility that the person gets in contact with the sewage water or bacteria/germs in the sewage water which could result in infections.
In an embodiment of the system, the top section and the intermediate structure of the duct part form a chamber wherein the submersible pump and one or more sensors are located. The top section further comprises a flushing device configured for cleaning the chamber. These features enable us to improve the cleaning of the interior of the system prior to detaching the top section.
In an embodiment of the system, the submersible pump comprises a crushing system. This feature allows us to use a submersible pump with a smaller size and consequently to reduce the dimensions of the duct element and top section. As a result, less soil has to be removed to place the duct element.
In an embodiment of the system, the controller is integrated in the top section. This feature provides a system which is easy to install as the system has only be connected to a power supply and a duct to drain the waste water pumped out of the duct element.
According to a third aspect of the invention, there is provided a product comprising all technical features of the top section according to second aspect for use with a duct element according to the first aspect.
According to a an embodiment, there is provide a flow profile part which when placed in the space of the intermediate structure of a duct element according to the first aspect provides the duct element a continuous flow profile from the inlet structure to the outlet structure.
According to a fifth aspect of the invention, there is provided a method of temporarily disconnecting a drainpipe of a building from a sewer main. The method comprises:

shutting the drainpipe at a location between the building and the sewer main;
cleaning the drainpipe downstream the location;
truncating the drainpipe downstream the location;
connecting a duct element according to the first aspect to the truncated drainpipe;
positioning a top section according to the second aspect on the opening of the duct element, the duct element and top section forming a watertight chamber;
closing the duct downstream the intermediate structure of the duct element;
opening the drainpipe upstream the intermediate structure; and
connecting the top section to a power supply.

This method is very suitable when renovating a sewer system while the toilets and other waste water generating units of a building are continuously used.
According to a sixth aspect there is provided a method of temporarily disconnecting a drainpipe of a building from a sewer main wherein the drainpipe comprises a duct element according to first aspect. The method comprises:

closing the drainpipe upstream the intermediate structure;
removing a lid from the opening of the duct element;
cleaning the duct element;
if present, removing a flow profile part from the space of the intermediate structure;
positioning a top section according to the second aspect on the opening of the duct element, the duct element and top section forming a watertight chamber;
closing the duct downstream the intermediate structure of the duct element;
opening the drainpipe upstream the intermediate structure; and
connecting to top section to a power supply.

This method is very suitable when the sewer main is temporarily out of use. There is no need to replace parts of the sewer system and the top section could be placed directly on the duct element according to the first aspect.
In an embodiment, the method further comprises:

closing the drainpipe upstream the intermediate structure;
opening the duct downstream the intermediate structure;
cleaning the watertight chamber formed by the duct element and the top section;
removing the top section from the duct element;
closing the opening of the duct element by a lid; and,
opening the drainpipe upstream the intermediate structure.

These features reduce the risk that a person gets in contact with the sewer in the sewer system.
In a further embodiment of the method, after removing the top section from the duct element, a flow profile part is placed in the space of the intermediate structure of the duct element resulting in a continuous flow profile through the duct element.
The terms "upstream" and "downstream" relate to an arrangement of items or features relative to the propagation of fluid through the system.
Other features and advantages will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, various features of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, properties and advantages will be explained hereinafter based on the following description with reference to the drawings, wherein like reference numerals denote like or comparable parts, and in which:

Fig. 1 shows schematically a sectional view of a first embodiment of a duct element;
Fig. 2 shows schematically a side view of the first embodiment;
Fig. 3 shows schematically a sectional view of a flow profile part;
Fig. 4 shows schematically a view of a top section;
Fig. 5 shows schematically a view of a drain pipe emptying system; and,
Fig. 6 shows schematically a sectional view of a second embodiment of a duct element.

DESCRIPTION OF EMBODIMENTS

Fig. 1 shows schematically a sectional view of a first embodiment of a duct element 2 according to the invention. The duct element 2 could be used in a sewage system or any other drainage system. The duct element could be arranged somewhere in the outlet pipe of a building draining fluid from the building to a sewer main. The arrows with reference numeral 5 indicate the flow direction of the fluid through the duct element 2. The terms "upstream" and "downstream" in the present description relate to an arrangement of items or features relative to the propagation of fluid through a system or structure.
The duct element 2 comprises an inlet structure 4, and outlet structure 6 and an intermediate structure 8. The duct element 2 could be made from a plastic material by an injection moulding process, such as polyvinyl chloride (PVC) and Polyethylene (PE). The inlet structure 4 is configured to couple the duct element with a first drainpipe of the sewage system upstream the duct element 2. The first drainpipe supplies fluid from the building to the duct element 2. The outlet structure 6 is configured to couple the duct element 2 with a second drainpipe of a sewage system. The second drainpipe is downstream the duct element and drains the fluid from the duct element 2 to the sewer main. In the embodiment shown in FIG. 1, the inlet structure 4 and the outlet structure 6 have different coupling structures. It might be clear for the person skilled in the art that any suitable coupling structure to connect a drain pipe to the duct element could be used. The diameter of the inlet structure 4 and the outlet structure 6 could be in the range 100 - 250 mm. Preferably, both structures 4, 6 have the substantially the same diameter. A watertight coupling between coupling structure of the duct element 2 and drainpipe might be obtained by gluing and by the use of one or more fittings.
The intermediate structure 8 forms a duct between the inlet structure 4 and the outlet structure 6. The inlet structure 4 and the outlet structure 6 protrude at opposite sides of the intermediate structure 8. The intermediate structure 8 is an open container formed by housing with an opening 8A. In FIG. 1 the opening 8A is closed watertight with a lid 3 in a conventional way. The opening 8A provides access to the inlet structure and outlet structure and enables one to inspect the conduits coupled to the duct element 2 and to clean or unclog the conduits.
The intermediate structure 8 further comprises a space 8B. The space 8B is the part of the cavity formed by the housing of the intermediate structure 8 which has a level which is below the inlet structure 4. How the space 8B will be used in an application will be described below. A wall 8C of the intermediate structure forms a bottom 8C of the structure. The bottom 8C comprises a substantially flat area so that a submergible pumping device (not shown) could be positioned on the bottom 8C. Bottom 8C is in a virtual plane.
The inlet structure 4 is a duct with a flow profile 4A. The lowest part of the flow profile 4A is in longitudinal direction of the duct basically parallel to the virtual plane. The inlet structure 4 is a duct having an upper side which in longitudinal direction of the duct is basically parallel to the virtual. The duct of the inlet structure has a circular cross section and a duct axis which is basically parallel to the virtual plane. The outlet structure 6 has a flow profile 6A. In Fig. 1, a detachable flow profile part 9 is positioned in the cavity of the intermediate structure 8. The detachable flow profile part 9 has a flow profile 9A. When the detachable flow profile part 9 is positioned in the cavity, the detachable flow profile part 9 provides the duct element 2 a continuous flow profile from the inlet structure 4 to the outlet structure 6. Continuous in the present context means that there is no significant change in height when fluid flows from the inlet flow profile 4A to the flow profile 9A of the flow profile part 9 and flows from the flow profile 9A of part 9 to the outlet flow profile 6A. In other words, the continuous profile defined by the inlet structure, detachable flow profile part and outlet structure is basically parallel to the virtual plane. In this way, the risk of clogging in the duct element 2 is reduced.
Fig. 2 shows schematically a side view of the first embodiment seen from the side of the outlet structure 6. The profile of the detachable flow profile part 9 is indicated by the dashed line. It can be seen that the flow profile 6A of the outlet structure 6 is aligned with the flow profile 9A of part 9. Furthermore, the flow profile 4A of the inlet part 4 is aligned with the flow profiles 9A and 6A.
Fig. 3 shows schematically a sectional view of the detachable flow profile part 9. The flow profile 9A is semi-circular. The wall of the flow profile 9A is extended at each side with a slanted wall 9B. The slanted walls 9B reduce the risk that waste material is collected in the cavity of the intermediate structure.
Fig. 4 shows schematically a sectional view of a top section 40 that could be placed on the intermediate structure 8 of the duct element 2 and closes watertight the opening 8A of the intermediate structure 8. The top section 40 comprises housing 41, a submersible pump 42, one or more sensors 44, a controller 46, a valve structure 47 and a flushing device 45. Fig. 5 shows schematically the situation wherein the top section 40 shown in Fig. 4 is positioned on the duct part 2 shown in Fig. 1. The combination forms a drain pipe emptying system 50 for temporarily disconnecting an outlet pipe of a building from a sewer main. The housing 41 of the top section 40 and the intermediate structure 8 of the duct part 2 form a chamber 52 wherein the submersible pump and one or more sensors are located. Figs. 4 and 5 do not show the means to affix the submersible pump 42 and sensor 44 in the housing 41.
When the top section 40 is positioned on the duct element 2, the submersible pump is positioned on the bottom 8C of the intermediate structure 8. The depth of the space 8 depends on the pumping characteristics of the submersible pump 42 and should be at least the minimum level needed by the submersible pump 42 to start pumping. It has been found that the bottom 8C of the space (8B) should be at least 5 cm lower than the underside of the flow profile 4A of the inlet structure 4. It has been found that for a commercially available submersible pump with crushing system a depth of 8 cm is sufficient to discharge the inlet structure and drainpipe coupled to the inlet structure. An advantage of a submersible pump with crushing system is that the dimensions of the pump and he diameter of the duct to discharge the fluid could be smaller. This allows to reduce the size of both the duct element 2 and the housing of the top section 40. The fluid pumped by the pump 42 is discharged via a duct which is outside the housing provided with a coupling 48 to couple a hose or any other discharge duct (not shown) to the outlet of the submersible pump 42.
In Figs. 4 and 5, a sensor arrangement 44 is shown. This sensor arrangement is a hollow body in which fluid can enter. In the hollow body two or three sensor are positioned. The sensors generate signals which enable the controller 46 to control, i.e. switch on/off, the submersible pump 42. The two or three sensor measure the level of fluid in the chamber formed by the housing 41 of the top section 40 and the housing of the intermediate structure 8. It should be noted that other sensors could be used, for example a floating switch.
In Figs. 4 and 5, the controller is an integral part of the top section. For the invention, it is not necessary that the controller 46 is in the housing of the top section 40. It might be possible that the controller is at distance from the housing and electrically connected to the pump 42 and one or more sensors 44 by wires. The controller 46 is further electrically coupled to a power supply (not shown). The power supply could be a mains or a battery.
The valve construction 47 is configured to prevent sewer or fluid in the cavity of intermediate structure 8 to enter the outlet structure 6. The valve construction 47 comprises a rod 47B. At one end the rod 47B is coupled to the housing 41 by a hinge 47A. A sealing member 47A is attached to the opposite side of the rod 47B. The sealing member 47A is at the level of the outlet structure 6 and configured to seal the opening of the outlet structure 6 when positioned in the opening. The sealing member 47A has a conical shaped body of a resilient material which material is resistant to the aggressive environment of a sewer system. An example of this material is rubber. The valve construction 47 further comprises a setting means 47D to move the sealing member 47A between an open and a closed position. Fig. 4 shows the valve construction 47 in the open position and Fig. 5 shows the valve construction 47 in the closed position. In the present embodiment, the setting means 47D is a bolt wherein the end of the bot is rotatable coupled to the rod 47B. By rotating the bolt 47D, the bolt will move along its rotation axis through the wall of the housing 41 and rotates the rod along the hinge 47C so that the sealing member 47A will move in/out the outlet structure 6 to closed/release the passage to the pipe attached to the outlet structure 6.
In another embodiment, the outlet structure comprises a closable opening. Through the opening, a balloon could be placed in the outlet structure to seal the outlet structure.
A flushing device 45 is provided at the top side of the housing 41 of the top section 40. The flushing device 45 is configured to clean the interior of the chamber 52 formed by the housing of the top section 40 and the duct element 2. The flushing device 45 could be connected outside the housing 41 to a clean water supply. In the chamber 52 one or more nozzles are provided to clean the surfaces in the chamber 52.
Below some applications of the duct element 2 and top section 40 will be described.
In the first application, the duct element 2 and top section 40 are used when renovating the outlet pipe and the sewer main. In that case, the sewer coming from the building could not be discharged for a period via the existing sewer system. Thus in this application a drainpipe of a building is temporarily disconnected from a sewer main. To avoid pollution of the soil by sewer and infection of the people renovating the sewer system, the following method is performed. First, the drainpipe of outlet pipe is closed at a location between the building and the sewer main. This could be done in a commonly known way by drilling a hole in the pipe and placing a balloon in the pipe to seal the pipe. Subsequently, downstream the deal, another hole is made in the pipe and the pipe is cleaned by flushing clean water through the pipe. Then the drainpipe is truncated downstream the location of the balloon. There is almost no risk for pollution and infection is this part of the pipe is cleaned. Subsequently, a duct element as described above is attached to the truncated drainpipe. Then, the top section 40 is positioned on the opening of the duct element 2. The duct element and the housing of the top section form a watertight chamber in which a submersible pump with corresponding sensors is positioned.. It is obvious that in the context of the present application "watertight" closed also means that the opening is air-tight sealed such that sewage gas cannot escape from the watertight chamber. The duct downstream the intermediate structure of the duct element is closed by moving the sealing member 47A in the outlet structure 6. It should be noted that by moving the sealing member 47 in the opening of the intermediate structure to the outlet structure, the top section is secured to the duct element 4. Both the sealing member 47A and an edge 41A of the housing 41 opposite the wall at which the valve construction is positioned ensure that the top section cannot be lifted from the duct element. Edge 41A cooperates with a protruding edge of the intermediate structure 8.
After the drainpipe upstream the intermediate structure is opened by removing the previously placed balloon in the drainpipe upstream the duct element 4, the sewer already collected in the drainpipe during mounting the duct element and positioning the top section flows in the chamber of the intermediate structure 4. The space 8B of the intermediate structure enables the duct element to collect a minimum amount of sewage before sewage is collected in the inlet structure 4 and enables a pumping device 42 to drain sewage from the space 8B. This allows sewage present in the inlet structure 4 to flow in the space 8B. By connecting the electronics of the top section to a power supply, the controller will receive signals from the one or more sensors which indicate the level of the sewage in the chamber. As soon as the level is above a level defined by a sensor, the pump will be switch on and starts discharging sewage from the chamber 52. When the level becomes below another level defined by a second sensor, the pump will be switched off. The chamber will then be filled again with sewage from the building. It should be noted that the level to switch the pump off is preferably below the level of the flow profile of the inlet structure. In this way, the outlet pipe up to the duct element is emptied regularly; as a result the outlet pipe will not clog by solid waste material, such as faeces, toilet paper, sanitary napkins. In this application, the combination of duct element and top section provided temporary means to bypass the connection with the sewer main by pumping the sewage to a temporary storage facility such as a mobile tank or another still working sewer main in the vicinity of the building.
When the sewer system is completely refurbished, the following actions have to be performed to drain the sewage from the building to the sewer main. First the drainpipe upstream the intermediate structure has to be closed. For this action, the hole drilled in the drainpipe of the outlet pipe upstream the duct element could be used to position a balloon to seal the drainpipe. Subsequently, the flushing device 45 is used to clean the interior of the watertight chamber formed by the duct element and the housing of the top section. The pump is still working and the sewage in the chamber will be diluted until the surfaces in the chamber are essentially clean. After this the duct downstream the intermediate structure is opened. This is done by moving the sealing element of the valve construction from the closed to the open position. The clean water can now flow away through the outlet structure and the duct attached to the sewer main. As the interior is now almost clean and the top section is unlocked from the duct element 4, a person could remove the top section with minimal risk to be infected by the sewer material. Furthermore, there is no risk that the soil will be polluted by sewerage. Subsequently, the person has to position the detachable flow profile part in the space of the intermediate structure of the duct element, which results in continuous flow profile through the duct element. The person could now close the opening of the duct element by the lid and open the drainpipe upstream the intermediate structure by removing the balloon out of the drainpipe.
In a second application, the sewer system already comprises a duct element in which a detachable flow profile part is positioned. To disconnect a building temporarily from a sewer main to following actions have to be performed. First, the drainpipe upstream the intermediate structure is closed by using the opening in the drainpipe upstream the duct element by positioning a balloon in the drainpipe. Then the lid is removed from the opening of the duct element. Preferably the lid, which hermetically seals the opening of the intermediate structure, is provided with a first tube like access structure. The first tube like access structure forms a passage for a suction hose through the lid to the space of the intermediate structure. The first tube like access structure further comprises a sealing member which is closed when no suction hose is positioned in the passage. A first example of a sealing member is a tilting valve at the end of the passage directed to the space of the intermediate structure. A spring pushes the valve against end of the first tube like access structure. By pushing a suction hose through the passage, the valve will be opened and sewage in the intermediate structure could be sucked out the intermediate structure before removing the lid. A second example of a sealing member is a ball valve. The ball valve is opened after an active suction hose is positioned in the passage. After the ball valve is opened the active suction hose could be pushed in the space of the intermediated structure. The use of a lid with the first tube like access structure reduces the risk that a person comes in contact with the sewage as the sewage is mainly removed before the lid is removed from the opening of the intermediate structure. Optionally, the lid comprise a second and/or a third tube like passage. The second and third tube like passage has a curvature that directs an inspection element or a cleaning nozzle at and end of a high pressure hose through the inlet structure and outlet structure. The second and third tube like passage are closed exterior by a removable closing member, for example a screw cap. After emptying the space in the intermediate structure, the second or third tube like passage could be opened without the risk that sewage is pushed though the passage. Subsequently, an inspection element or high pressure hose could be pushed through the sewage pipe attached to the inlet and/or outlet structure to inspect or to clean the attached sewer pipes. In this way, the sewer system could be inspected/cleaned without removing the lid from the intermediate structure. It should be noted that a lid having at least one of the three tube like passages could be used on existing inspection pipe elements.
If necessary after removing the lid from the intermediate structure, the duct element and surface of the flow profile part in the intermediate structure is cleaned. Then, the flow profile part is removed from the space of the intermediate structure and the top section is positioned on the opening of the duct element. Subsequently, the entry to the duct downstream the intermediate is closed by the valve construction, the drainpipe upstream the intermediate structure is opened again by removing the balloon. The top section is coupled to a duct to drain the sewage pumped out of the chamber formed by the housing of the top section and intermediate structure to a storage tank or a working sewer main in the vicinity of the building. Finally, the top section is electrically connected to a power supply.
It might be clear that the method described above could also be used in case the drainpipe downstream the duct element has to be replaced or repaired.
It should be noted that the inlet structure 4 and the outlet structure 6 have a duct diameter and the duct of the intermediate structure, i.e. the distance between the inlet structure and the outlet structure has a length which is longer than the duct diameter of the inlet structure. This is due to the size of the submersible pump. That's why an inspection chamber with sampling facility could not be used.
It should further be noted that instead of a submersible pump a suction pump could be used to drain the sewage from the duct element. In this case, the submersible pump in the top section is replaced by a suction pipe with a suction nozzle which enables the pipe to suck sewerage out of the space of the intermediate structure. Sensors are still needed to activate and deactivate the vacuum pump to generate the vacuum to suck the sewage away.
Fig. 6 shows a second embodiment of a duct element. This embodiment differs from the first embodiment in that the flow profile 6A' of the outlet structure 6' is aligned with the bottom 8C of the intermediate structure. To close the opening to the outlet structure, the valve construction described above has to be adapted. This could be done by extending the rod and slightly modifying the shape of the sealing element. An advantage of this embodiment is that no detachable flow profile part is needed. A disadvantage is that is requires additional height difference between outlet of the building and sewer main to provide the required inclination of the duct. This height difference is not always available.

Claims

A duct element (2) for use in a sewage system, the element comprising:
- an inlet structure (4) configured to couple the duct element with a first drainpipe of the sewage system,

- an outlet structure (6) configured to couple the duct element with a second drainpipe of a sewage system; and,

- an intermediate structure (8) forming a duct between the inlet structure (4) and the outlet structure (6), wherein the inlet structure (4) and outlet structure (6) are protrusions at opposite sides of the intermediate structure, the intermediate structure (8) comprises a space (8B) with a flat bottom (8C) in a plane and an opening (8A) to provide access to the space, the inlet structure and outlet structure,
characterized in that
the inlet structure (4) forms a duct having an upper side which in longitudinal direction is basically parallel to the plane of the flat bottom, furthermore, when the opening (8A) and outlet structure are closed watertight by sealing elements the space (8B) enables the duct element to collect a minimum amount of sewage in the space before more sewage is collected in both the space and the first drainpipe, the minimum amount enables a pumping device (42) to drain sewage from the space (8B) and to generate a flow of sewage water through the inlet structure (4) to fully discharge the first drainpipe.
The duct element (2) according to claim 1, wherein the inlet structure (4) has a flow profile (4A) and the flat bottom (8C) of the space (8B) is at least 5 cm lowered with respect to the flow profile (4A) of the inlet structure (4).
The duct element (2) according to claim 2, wherein the outlet structure (6) comprises a flow profile (6A) which is aligned with the flow profile (4A) of the inlet structure (4), the intermediate structure (8) is further configured to receive a detachable flow profile part (9) which profile part provides the duct element a continuous flow profile from the inlet structure (4) to the outlet structure (6).
The duct element (2) according to claim 3, wherein the inlet structure (4) and the outlet structure (6) have a duct diameter, the duct of the intermediate structure has a length which is longer than the duct diameter of the inlet structure.
The duct element (2) according to any one of the claims 1 - 4, wherein the inlet structure (4) and the outlet structure (6) have a duct diameter in the range 100 - 250 mm.
The duct element according to any one of the claims 1 - 5, wherein the pumping device (42) is a submersible pump.
A drain pipe emptying system (50) for temporarily disconnecting an outlet pipe of a building from a sewer main, the system comprising a duct element (2) according to any one of the claims 1 - 6 and a top section (40) which closes watertight the opening (8A) of the intermediate structure of the duct element, wherein the top section (40) comprises a submersible pump (42), one or more sensors (44) generating signals enabling a controller (46) to control the submersible pump (42) and a coupling structure (48) to couple a discharge duct to the submersible pump (42).
A system according to claim 7, wherein the top section (40) further comprises a valve construction (47) configured to prevent sewage in the intermediate structure (8) to enter the outlet structure (6).
A system according to any one of the claims 7 - 8, wherein the top section (40) and the intermediate structure (8) of the duct element (2) form a chamber (52) wherein the submersible pump (42) and one or more sensors (44) are located, the top section further comprises a flushing device (45) configured for cleaning the chamber.
The system according to any one of the claims 7 - 9, wherein the submersible pump (42) comprises a crushing system.
The system according to any one of the claims 7 - 10, wherein the controller (46) is integrated in the top section (40).
A product comprising all technical features of the top section according to any of the claims 7 - 11.
A method of temporarily disconnecting a drainpipe of a building from a sewer main, the method comprising:
- shutting the drainpipe at a location between the building and the sewer main;

- cleaning the drainpipe downstream the location;

- truncating the drainpipe downstream the location;

- connecting a duct element according to any one of the claims 1 - 5 to the truncated drainpipe;

- positioning a top section according to claims 12 on the opening of the duct element, the duct element and top section forming a watertight chamber;

- closing the duct downstream the intermediate structure of the duct element;

- opening the drainpipe upstream the intermediate structure; and

- connecting the top section to a power supply.
A method of temporarily disconnecting a drainpipe of a building from a sewer main wherein the drainpipe comprises a duct element according to any one of the claims 1 - 5, the method comprising:
- closing the drainpipe upstream the intermediate structure;

- removing a lid from the opening of the duct element;

- cleaning the duct element;

- if present, removing a flow profile part from the space of the intermediate structure;

- positioning a top section according to claim 12 on the opening of the duct element, the duct element and top section forming a watertight chamber;

- closing the duct downstream the intermediate structure of the duct element;

- opening the drainpipe upstream the intermediate structure; and

- connecting the top section to a power supply.
Method according to claim 13 or 14, wherein the method further comprises:
- closing the drainpipe upstream the intermediate structure;

- cleaning the watertight chamber formed by the duct element and the top section;

- opening the duct downstream the intermediate structure;

- removing the top section from the duct element;

- closing the opening of the duct element by a lid; and,

- opening the drainpipe upstream the intermediate structure.
Method according to claim 15, wherein after removing the top section from the duct element, a flow profile part is placed in the space of the intermediate structure of the duct element resulting in a continuous flow profile through the duct element.