WO2023084112A1

WO2023084112A1 - Sectional coupling for connecting pipe-n-pipe sections in a water supply system

Info

Publication number: WO2023084112A1
Application number: PCT/EP2022/081982
Authority: WO
Inventors: Per Henriksen
Original assignee: Notio As
Priority date: 2021-11-15
Filing date: 2022-11-15
Publication date: 2023-05-19
Also published as: SE2450540A1; NO20211375A1; FI20245712A1

Abstract

The invention describes a sectional coupling (4) for connecting pipe-in-pipe sections (1) to form a pipe loop to circulate water (5) through a building. The sectional coupling (4) comprises a watertight fixture box (6) with a closable opening (7) for a water outlet (8), at least one pair of connection openings (9) for safety pipes (3), and a wall passage (21) with a fixture box cover (20) at least two safety pipe couplings (22) each for connecting a safety pipe section (3) to respective connection openings (9) in the fixture box (6). Furthermore, the sectional coupling comprises at least one water pipe coupling (10) for connecting the inner flexible water pipe sections (2) to adjacent pipe-in-pipe sections (1), where the water pipe coupling (10) is configured to be disconnectable from the inner flexible water pipe sections (2) in the fixture box (6). The fixture box (6) has at least a free volume with a width of at least one pipe diameter so that each of the internal flexible water pipe sections (2) can be pulled through the free volume and out of the wall passage (21) in respective extraction paths (29) when the water pipe coupling (10) is disconnected, thereby making each individual water pipe section replaceable.

Description

SECTIONAL COUPLING FOR CONNECTING PIPE-IN-PIPE SECTIONS IN A WATER SUPPLY SYSTEM

Description

The subject area of the invention

The invention relates to a water supply system for a building. More specifically, the invention relates to a pipe-in-pipe circular and sectioned water supply system which is built into the floor, wall and/or ceiling where each individual water pipe section is replaceable.

Background

Pipe-in-pipe systems are well known and provide greater security against water leaks. If a water pipe section leaks, an outer waterproof corrugated safety pipe that encloses the water pipe section will prevent the leak from reaching materials that might be destroyed by water. Pipe-in-pipe systems usually have one distributor cabinet and piping from the distributor cabinet to each individual tapping point as shown in fig. 1. In newer buildings, the pipelines are laid inside the wall, and by ensuring that none of the pipelines have too sharp changes in direction, a broken water pipe can be pulled out of the corrugated safety pipe and a new water pipe can be threaded into the corrugated safety pipe. This works when the water pipe section has a flexibility that allows the water pipe section to tolerate the changes in direction that the corrugated safety pipe is laid in. It is common to use PEX pipes in pipe-in-pipe systems, but other flexible water pipes can also be used.

In recent times, more and more of the water pipes are built into walls, floors and ceilings. The Norwegian authorities' requirement for allowing water installations to be hidden is that water pipes and parts touched by water must be replaceable. Furthermore, the system must be leakproof, and any leakage must be shown and directed to a drain without damaging the building.

Circular water systems are also known technology. One of the advantages of a circular system is that significantly smaller pipe is used in terms of length. Examples of circular water supply systems are e.g. described in US 2012204981 Al or CA2425237 Al.

A common problem in residential water supply is that a lot of water disappears when the user lets the water run until the water from the hot water tap becomes hot or the water from the cold-water tap becomes cold.

Furthermore, it is a problem that built-in circular pipe-in-pipe systems cannot be made interchangeable because the fact that the pipe is in a loop requires that there is a T-coupling or similar at any tapping point inside the wall. At the same time, users do not want to have a large opening to the contact point due to aesthetic considerations.

Furthermore, it is a problem that connections with flexible PEX pipes tend to loosen over time, especially hot water PEX pipes.

Furthermore, there is a problem that connecting safety pipes to fixture boxes in pipe-in-pipe systems can be demanding due to limited space.

There is also a problem with the amount of pipes needed in a pipe system where one pipe goes to each tapping point. There is a need for a water supply system that at least partially solves the aforementioned problems.

Summary of the invention

In a first aspect of the invention, a sectional coupling is described for connecting pipe-in-pipe sections, each comprising an inner flexible water pipe section and an outer safety pipe section, to form a pipe loop for water through a building. The sectional connection comprises a watertight fixture box, at least two safety pipe couplings and at least one water pipe coupling.

The fixture box comprises a closable opening for a water outlet, at least one pair of connection openings for safety pipes and a wall passage with a fixture box lid, arranged with 0 - 2 fitting connections. The sectional connection comprises at least two safety pipe couplings each for connecting a safety pipe section to respective connection openings in the fixture box. The water pipe coupling is intended for connecting the inner flexible water pipe sections to adjacent pipe-in-pipe sections, where the water pipe coupling is configured to be able to be disconnected from the inner flexible water pipe sections in the fixture box. The fixture box has a free internal volume comprising the volume between the connection openings and the volume of the wall passage where each of the internal flexible water pipe sections can be pulled through the free volume and out of the wall conduit in respective extraction paths when the water pipe coupling is disconnected, where the bending radius of the water pipe sections is greater than the minimum permissible bending radius of the water pipe section.

In one embodiment of the invention, the sectional coupling is built into a wall.

In a further embodiment of the invention, the sectional coupling comprises a simple armature box. The fixture box comprises a pair of fixture box expansions on opposite sides to accommodate respective extraction paths and a connection opening for safety pipes positioned on each fixture box extension. Respective extraction paths for respective flexible water pipes of a given diameter are produced by an inner radius of the pipe being extracted, being pressed against an inner upper edge of the inner fitting cover at the wall passage and by an outer radius of an arc of the water pipe section being extracted, being pressed against the lower inner edge of the connection opening and a contact surface on the side of the wall passage opposite the inner upper edge.

In a further embodiment of the invention, the sectional coupling comprises a double armature box. The double fixture box comprises a pair of connection openings for safety pipes for hot water, and a pair of connection openings for safety pipes for cold water. Furthermore, the double fixture box comprises two water pipe couplings for connecting respective internal flexible water pipe sections at respective adjacent pipe-in-pipe sections.

In a further embodiment of the invention, the sectional coupling comprises a 0-180 degree fixture box. The 0 - 180 degree fixture box comprises a back side, a connection opening for safety pipes on a first and a second side on each side of the back side (right and left side). The two connection openings are located on a common center line L. The 0 - 180 degree box also comprises two connection openings for safety pipes located on an opposite side of the back side, and an inner fixture box cover on which the wall conduit is attached. The water pipe coupling is a T-coupling with a T-coupling housing comprising two water pipe openings with an essentially 90 degree angle between them and associated stubs with an angle of mainly 45 degrees between an attachment to the flexible water pipe and an attachment to the T-coupling housing. The T-coupling housing is shifted towards the back side of the 0-180 degree fixture box so that the aforementioned attachment to the water pipe on the sockets lies along the center line of each connection opening, and where the center line, M, between the two water pipe openings runs midway between the two connection openings on the opposite side . Respective extraction paths for respective flexible water pipes of a given diameter are produced by an inner radius of the pipe being extracted, being pressed against an inner upper edge of the inner fitting cover at the wall passage and by an outer radius of an arc for water pipe sections being extracted, being pressed against the lower inner edge of the connection opening and a contact surface on the side of the wall passage opposite the inner upper edge.

In a further embodiment of the invention, the water pipe coupling comprises a T-coupling housing comprising two water pipe openings and a socket where the flexible water pipe is attached to an outer end of the socket by a spring-loaded clamping ring and where the socket has a coupling structure at the opposite end of the socket which fits releasably and watertight into a corresponding structure in the T-coupling.

In a further embodiment of the invention, the water pipe coupling comprises a socket flange on the respective sockets that fits into respective flange slots at the bottom of the fixture box and where the wall passage, when screwed down, presses a stabilization unit against the sockets and the T-coupling housing so that the respective socket flanges are held in place in the respective flange slots.

In a further embodiment of the invention, the water pipe coupling comprises a coupling housing flange at the water pipe opening and a flange clamp which clamps the socket flange of the socket and the coupling housing flange together.

In a further embodiment of the invention, the water pipe coupling comprises a pipe extension of the T-coupling housing which extends past an fixture connection in the fixture box cover and is connected watertight to this by means of an O-ring, where the pipe extension is cut to the correct length after assembly.

In a second aspect of the invention, a pipe-in-pipe circular water supply system is described where a plurality of pipe-in-pipe sections are connected together to form a pipe loop for water by means of sectional connections according to claims 1-10.

In one embodiment of the invention, the circular water supply system comprises a circulation pump which ensures a minimum water flow in the circular water supply system.

In a further embodiment of the invention, the circular water supply system comprises a pipe loop for hot water and a pipe loop for cold water.

In a further embodiment of the invention, the circular water supply system comprises a pipe loop for hot water which passes through a water heater.

In a further embodiment of the invention, the circular water supply system comprises a pipe loop for cold water which passes through a cold water heater. In a further embodiment of the invention, the circular water supply system comprises at least one peltier element connected with a cold side to the pipe loop for cold water and a hot side to the pipe loop for hot water.

Brief description of the figures

To facilitate the understanding of the invention, there are attached figures illustrating different embodiments of the invention where like numbers in different figures refer to the same features.

Fig. 1 shows a conventional water supply system according to prior art.

Fig. 2 shows a circular water supply system according to the invention.

Fig. 3 shows the water supply system from fig. 2 more schematically.

Fig. 4 shows an embodiment of a single fixture box according to the invention.

Fig. 5 shows an embodiment of a double fixture box according to the invention

Fig 6 shows the fixture box from fig. 5 in exploded version.

Fig. 7a - d shows an embodiment of a 0 - 180 degree fixture box according to the invention.

Fig. 8a and b show the two versions of the fixture boxes mounted in the wall.

Fig. 9 shows the fixture box from fig. 6 with a water pipe that is pulled out via a pull-out path.

Fig. 10 shows a fastening nipple for safety pipes.

Fig. 11 shows a water supply system with peltier-elements for cooling

Detailed description

In the following, we will describe a pipe-in-pipe circular water supply system for a building. To simplify the language, we indicate directions as if the fixture box were on the floor with the opening for the water outlet straight up. The water supply system comprises a plurality of pipe-in-pipe sections 1 built into the wall, floor and/or ceiling as shown in fig. 2 and 3. Each pipe-in-pipe section 1 according to the invention comprises an inner flexible water pipe section 2 and an outer safety pipe section 3 which lies outside the inner flexible water pipe section 2. This is indicated in fig. 5-7. Preferably, the safety pipe 3 is of a corrugated type.

Furthermore, the water supply system comprises a plurality of pipe-in-pipe sectional connections 4 which connect the plurality of pipe-in-pipe sections 1 circularly through the building to form a pipe loop for water 5. Fig. 4 - 7 show examples of sectional connections. Each sectional coupling 4 comprises a watertight fixture box 6 with a closable opening 7 for a water outlet 8 and connection openings 9 for safety pipes. The opening 7 is sealed by means of an fixture box cover 20 which is preferably attached to a wall passage 21 which is cut to the correct length so that the fixture box cover 20 lies flush with the wall 26 as shown in fig. 8. The fixture box cover can be completely covered as shown in fig. 6 or equipped with a water outlet 8 as shown in fig. 4 and 5. There must necessarily be at least two connection openings 9 for safety pipes on the fixture box because the fixture box is part of a pipe loop for water 5. Although there is always one water pipe 2 in each safety pipe 3, there can be two pipe loops for water that are connected to the same sectional connection 4, for example a pipe loop for cold water 5a and a pipe loop for hot water 5b to the same sectional connection 4. The safety pipe 3 is connected in a watertight manner to the fixture box 6 by means of a safety pipe coupling 22. It may be desirable to have an additional water outlet from the fixture box 6, e.g. to a toilet.

In one embodiment, shown in FIG. 4, the safety pipe coupling 22 comprises a nipple 23 where the safety pipe is attached to a nipple socket 28, where a clamping nut/nipple 23 clamps onto a clamping gasket 25. The nipple 23 is attached to the connection opening 9 with threads that match corresponding threads in the connection opening 9.

Each sectional coupling 4 comprises at least one water pipe coupling 10 for connecting the inner flexible water pipe sections 2 to adjacent pipe-in-pipe sections 1. The water pipe coupling 10 is configured to be able to disconnect the inner flexible water pipe sections 2 in the fixture box 6.

In general, any fixture box 6 according to the invention has a free volume, without obstacles or physical structures where an extraction path 29 is located. The free volume comprises the volume between the connection openings 9 and the volume of the wall passage 21 where each of the inner flexible water pipe sections 2 can be pulled through the free volume and out of the wall passage 21 in respective extraction paths 29 when the water pipe coupling 10 is disconnected, where the bending radius of the water pipe sections is greater than the minimum permissible bending radius to the water pipe section.

The angle between the pipes entering and exiting the fixture box 6 can be 90 or 180 degrees in the single fixture box 6a. In the double fixture box 6b, the angle can also be 0 degrees. This means that all the pipes come out and into the fixture box 6 on the same side.

In another, not shown, embodiment, the safety pipe coupling 22 can be a flange which is glued, melted, clamped or screwed onto the end of the safety pipe 3 and then attached to the coupling housing 6 in a similar way.

Single fixture box

In a first embodiment of the sectional coupling 4, shown in fig. 4, the diameter of the opening 7 for water outlet in the fixture box 6 is substantially equal to the inner width of the fixture box. The safety pipe coupling 22 is attached to a fixture box extension 41 which in turn is screwed into an expansion opening 51 or the fixture box extension 41 is integrated into the fixture box 6. The purpose of the fixture box extension is to enable the extraction of the inner flexible water pipe section 2 through the wall passage 21 as shown in fig. 9. The fixture box expansion enables a larger radius of the arc described by the inner flexible water pipe section 2 when it is to be pulled out of the fixture box 6 for replacement. We can call this a single fixture box 6a which can handle one pipe loop. This embodiment produces an extraction path 29 with an arc that has a greater radius than the smallest radius an arc to the inner flexible water pipe section can have when extracting the water pipe section 2 through the opening 7 for water outlet and the wall passage 21. Simply put, it should be possible to pull a water pipe section 2 out through the wall passage 21. More precisely, a lower inner edge 42 of the connection opening 9, an inner upper edge 43 of the fixture box at the opening 7 for the water outlet and a contact surface 44 on the side of the wall passage 21 opposite the inner upper edge 43 where the water pipe section hits when extracting, describes 3 points as a pipe of a given diameter and flexibility is pressed against when extracted. The outer radius of an arc of the water pipe section being extracted is pressed against the lower inner edge 42 and the contact surface 44 on the side opposite the inner upper edge 43. The inner radius of the pipe being extracted is pressed against the inner upper edge 43. The two mentioned edges 42 and 43 and the contact surface 44 define the extraction path 29 of a water pipe of a given diameter. There is at least one extraction path 29 for each water pipe 2 which is connected to the water pipe coupling 10.

Figure 4 shows an advantageous embodiment of the fixture box where a fixture box base 46 has a pipe groove 47 for a water pipe 2 on both sides of a coupling housing groove 48 which is adapted to the bottom of the T coupling housing 11 and where a flange groove 49 on each side of the coupling housing groove 48 is adapted to a socket flange 50 on the socket so that the two sockets are locked against the flange groove when the water pipe and T-coupling housing are held down in their respective grooves. Preferably, the stabilization unit 24 is equipped with permanent formations so that water pipes and fittings are effectively prevented from detaching from the T-coupling housing when the wall passage presses the stabilization unit 24 against the bottom of the fixture box 6. Subfigure A in fig. 4 shows the pipe groove 47 and the flange groove 49 in the fixture box base 46 and the stabilization unit 24 seen from the side. Subfigure B in fig. 4 shows the fixture box base 46 seen from above where the T- coupling housing 11 and the water pipe section 2 are shown as dashed lines. Sub figure C in fig. 4 shows an assembled single fixture box 6a.

The fixture box 6a is configured so that the inner flexible water pipe section 2 can be pulled out of the opening 7 in the fixture box when the inner flexible water pipe section 2 is disconnected from the water pipe couplings 10 at both ends of the pipe-in-pipe section 4 to be replaced, thereby making each pipe section in the pipe loop replaceable. In some embodiments, the water pipe coupling 10 must be removed before the water pipe section can be pulled out. An operator must be able to insert his hands or a tool into the fixture box 6 and detach the water pipe section from the water pipe coupling 10 and then pull the relevant section of the water pipe section 2 out through the opening 7 to the fixture box 6. The aforementioned disconnection can take place by cutting the water pipe section at the connection 14 , by the water pipe section being detached from the socket by opening the spring-loaded clamping ring 19 and by the socket 14 being detached from the T-coupling housing 11.

Double fixture box

In a second embodiment of the sectional coupling 4 shown in fig. 4 and 5, the fixture box 6 comprises a pair of connection openings 9 for safety pipes 3 for hot water and a pair of connection openings for safety pipes 3 for cold water. Therefore, this design can be called a double fixture box 6b. The double fixture box 6b is large enough to accommodate two outlets at a distance from each other. The large double fixture box 6b makes it easy to get to when disconnecting pipe sections when replacing them. The same Water pipe coupling 10 and safety pipe coupling can be used, and this design also comprises a wall passage 21 and a fixture box cover 20. In this design, there is no need for a fixture box extension 41 because the double fixture box is large enough. A natural choice of shape for the fixture box is a rectangular shape of approximate size 20 X 8 cm to accommodate a cold and a hot connection at a distance of 15 cm which is the standard distance for mixer taps as shown in fig. 4.

The respective extraction paths 29 in the double fixture box can be chosen relatively freely due to the size of the opening 7 for water outlet in the fixture box. The double fixture box can also comprisean additional water outlet 8 for e.g. a toilet. Generally, the double fixture box 6b is very advantageous in terms of access for plumbers, but many users find it too dominant on the wall and prefer a smaller fixture box 6.

Fixture box 0-180 degrees

In a third embodiment of the sectional coupling 4 shown in fig. 7a and b, the water pipe coupling 10 comprises two water pipe openings 12 with a 90 degree angle between them and associated sockets 14 with an angle of 45 degrees between the attachment to the flexible water pipe section 2 and the attachment to the T-coupling housing 11. The T-coupling housing is shifted towards a back side 32 of a 0-180 degree fixture box 6c with a connection opening 9 for safety pipes on its right 33 and left 34 sides, which lie in line, and two connection openings 9 for safety pipes on the opposite side 35. The center line between the two water pipe openings 12 runs midway between the two connection openings 9 on opposite side 35. The socket 14 for the inner flexible water pipe section has an angle of 45 degrees and the centerline of the T-coupling housing 12 (which is perpendicular to the water pipe openings 12 and associated water pipe 2) passes through a point that passes through the center line between the two safety pipe coupling openings 9 on the opposite side 35, and which is a distance from the line between the right and left connection opening that corresponds to the distance D from the center line of the T-coupling housing to the breaking point on the socket multiplied by the cosine of 45 degrees. Between the center lines of the two connection openings 9 for safety pipes on the opposite side 35, there is a distance 2D. This configuration makes it possible to achieve 0, 90 and 180 degrees between the water pipes which are connected to the fixture box 6 by turning the sockets 14 and using the respective connection openings 9 for safety pipes. Respective extraction paths 29 for respective flexible water pipes of a given diameter are produced by an inner radius of the pipe being extracted, being pressed against an inner upper edge 43 of the inner fitting cover 40 at the wall passage 21 and by an outer radius of an arc to the water pipe section 2 being extracted , is pressed against the lower inner edge 42 of the connection opening 9 and a contact surface 44 on the side of the wall passage opposite the inner upper edge 43.

The Water pipe coupling

The sectional coupling 4 comprises a water pipe coupling 10 for connecting the inner flexible water pipe section 2 to adjacent pipes in pipe sections 1, where the water pipe coupling 10 is configured to be removable in the fixture box 6. In fig. 4 it is shown a single fixture box 6a with a water pipe coupling 10 which is of the T-coupling type. In this embodiment, the water pipe coupling 10 comprises a T-coupling housing 11 with two water pipe openings 12 and an outlet opening 13. A socket 14 can be inserted into the two water pipe openings which is held in place by means of a bias and which is sealed, e.g. with an o-ring and where the flexible water pipe section 2 can be attached to the socket 14, for example by means of a spring- loaded clamping ring 19. A connection structure in the opposite end of the socket 14 fits watertight into a corresponding structure in the T-coupling. With this solution, the socket 14 can be detached from the T-coupling housing 11, e.g. with a screwdriver of the flat iron type and the T-coupling housing will be able to be pulled out to enable the flexible water pipe section 2 to be pulled out through the opening 7 for water outlet in the single fixture box 6a.

In an embodiment of the water connection 10, shown in fig. 4, the T-coupling housing 11 is equipped with an outlet opening 8 with internal threads for connecting a water pipe that goes to a fixture connection 27

In a further embodiment of the water pipe coupling 10, a pipe extension 54 of the T-coupling housing 11 extends past a fixture connection 27 in the fixture box cover 20 and is connected watertight to this by means of an O-ring 30 as seen in fig. 4. Excess length of the pipe extension 54 of the T-coupling housing is cut off after mounting the fixture connection 27 and before connecting the armature or mixer tap.

In one embodiment of the water pipe coupling 10, the socket 14 is attached to the T-coupling housing with a flange clamp 31 as shown in fig. 7c. The flange clamp 31 grips a socket flange 50 on the socket 14 and a coupling housing flange 52 on the T-coupling housing 12 and holds them together. The flange clamp 31 is preferably spring-biased and can be loosened by e.g. a screwdriver and put on with a pair of pliers. In an advantageous embodiment, one of two movable parts of the flange clamp 31 is fixedly mounted in the bottom so that the socket flange can be inserted into the flange clamp 31 and the other of the movable parts of the flange clamp can be tilted over to lock with the other movable part.

In a further embodiment of the water connection 10, shown in Fig. 6, the socket 14 is integrated into the T-coupling housing and the flexible water pipe section is attached to the socket by threading it over the socket, preferably with the help of heat, and is further secured with the help of a spring-loaded clamping ring 19. The end of the water pipe section 2 can also be expanded to avoid a narrowing of the flow path in the pipe loop 5. In such an embodiment, the simplest method of changing a pipe section can be to cut across the water pipe section 2 at the socket 14, especially if the expanded end to the water pipe section is too large for the safety pipe. All versions of the water pipe couplings 10 can be used in the three described versions of fixture boxes 6a, 6b and 6c.

PEX pipe

In one embodiment, the flexible water pipe section 2 is of the PEX pipe type. A PEX pipe has many beneficial properties such as flexibility and thermal memory. This means that if the pipe gets a bend it can be heated and regain its original shape. Another characteristic of PEX pipes is that if the PEX pipe is attached using a screw connection, the connection will need to be retightened after a few years. This applies in particular to pipes that conduct hot water. The reason is linked to thermal memory. After repeated temperature fluctuations, the PEX pipe will 'believe' the pressed shape that emerges of the screw connection is the original shape. This can be solved by using a spring-loaded clamp 19 to secure the PEX pipe. Then the pretension in the spring will compensate for changes in the PEX pipe and the need for retightening is gone. An advantage that arises from reducing the diameter of the PEX pipe is that the PEX pipe becomes more flexible and it is a property that is beneficial when the PEX pipe is to be replaced and pulled out through the opening 7 in the fixture box 6. During this operation, there is also an advantage that the PEX pipe 2 is attached to the T-coupling/Water pipe coupling by means of a socket 14 and a spring-loaded clamp 19 which does not increase the diameter to any great extent as a traditional screw solution/nipple would do. Socket 14 and spring-loaded clamp 19 are then pulled out together with the water pipe section 2 if the diameter of the safety pipe allows it, otherwise the socket and clamp must also be disconnected.

The water supply system according to the invention is a circular system where the water can come from both sides, which means that the flow area of the water pipe section can be reduced in relation to a solution where one pipe goes to each tapping point. A prerequisite for a reduction of the flow area of the water pipes being possible is a low degree of simultaneity. This means that the tap points are rarely used at the same time. Consequently, there will be clear limitations on how large a water supply system according to the invention can be. Sizes such as a detached house or a unit will work. Larger units must be divided into smaller units that are supplied with cold water.

In order to achieve a solution with instantly available cold and hot water, it is advantageous to set up a slow circulation in the pipe loop for water using a circulation pump 16. A lot of water is lost when the user lets the water flow until the water from the hot water tap becomes warm or the water from the cold water tap becomes cold. If there is a constant circulation in the pipe loop for hot water 5b and the pipe loop goes through the water heater 17, the hot water will be immediately available at all tap points. The pipe loop for cold water 5a will immediately provide cold water without the use of a cold water cooler 18 if there is a consumption that causes the same water not to be circulated for too long. In order to immediately provide cold water for all situations, a cold water cooler 18 and a circulation pump 16 are necessary. The cold water cooler 18 can be designed as an expansion vessel with a volume that satisfies both the cold water demand and the expansion volume of the water heater 17. In this way, the cold water cooler 18 will be able to fulfill two functions and eliminate the need for a separate expansion tank in systems with a tight non-return valve on the intake or systems with high pressure. Preferably, the cold water cooler 18 is connected to the pipe loop so that the water flows through it.

However, a smaller cold water cooler 18 is sufficient because the temperature difference between room temperature and desired cold water temperature is relatively small and when water coming directly from the main water line reaches the pipe loop for cold water 5a, the need for cooling will usually disappear. In warmer regions, a cold water cooler may be more relevant.

Water supply system with peltier elements

In an advantageous embodiment, shown in fig. 11, the water supply system is provided with at least one peltier element 53. A peltier element is a device that provides a cold side and a hot side when current is applied and is widely used for cooling electronics. At least one peltier element 53 is positioned with the cold side towards the pipe loop for cold water 5a and the hot side towards the pipe loop for hot water 5b. Preferably, the hot side is connected at the entrance to the hot water tank and the cold side to the start of the pipe loop for cold water, that is near the intake of the pipe loop for cold water 5a. Furthermore, the at least one peltier element 53 is thermostatically controlled by the temperature of the water in the pipe loop for cold water. The at least one peltier element is dimensioned to be able to emit as much cold as the pipe loop for cold water 5a absorbs from heat on the hottest days when the circulation pump 16 runs and the temperature is kept at the desired level. This will be sufficient if the cold water coming from the main line maintains a temperature that is close to the desired temperature of the cold water. If this temperature difference is too great, a cold water cooler 18 must be used. A combination of peltier elements 53 and cold water cooler 18 is also possible.

Safety pipe attachment comprising attachment nipple

Fig. 10 shows an embodiment of the safety pipe attachment 22 for corrugated safety pipe 3 comprising a fastening nipple 36 and a fastening sleeve 37. The fastening nipple has a mainly cylindrical shape and is made of a flexible sealing material that fits into the fastening sleeve 37 and comprises a stop flange 39 in an outer end which prevents the fastening nipple 36 from being pushed too far into the fastening sleeve. Furthermore, the attachment nipple comprises a conical part 38 which has a larger diameter and thicker material at an inner end of the attachment nipple. Preferably, the fastening nipple is approximately the same length as the fastening sleeve 37 and when the fastening nipple 36 is placed in the fastening sleeve 37 and the safety tube 3 is pressed into the fastening nipple 36, the conical part 38 will be stretched past the fastening sleeve so that the fastening nipple can expand due to the elasticity of the material, while when the safety tube is pulled back, the conical part 38 locks between the safety tube 3 and the fixing sleeve. Preferably, the fastening nipple 36 has rifles 45 that match the shape of the corrugated safety pipe 3 in order to thereby increase friction when the safety pipe is affected by forces that pull it out of the fixture box 6. To detach the corrugated safety pipe from the fastening nipple, the operator must pull the safety pipe outwards while the fastening nipple is pulled in the opposite direction e.g. with a pair of pliers. To facilitate this task, it may be advantageous to have a gripping tab at the end of the fastening nipple 36 that faces inwards into the fixture box 6

Furthermore, in the lower part of the pipe loop, at least one leakage outlet 15 has been placed for leakage water from the safety pipe as shown in figures 2 and 3. The leakage outlet 15 will work as a leak detector and should comprise that the leaking water is directed to a drain, for example by means of a pipe.

Reference list

1 Pipe in pipe section

2 inner flexible water pipes

3 Outer corrugated safety pipe

4 Sectional coupling

5 pipe loop for water

5a pipe loop for cold water

5b pipe loop for hot water

6 Fixture box

6a Single fixture box

6b Double fixture box

6c 0 - 180 degree fixture box

7 Opening for water outlet in fixture box

8 Water outlet

9 Connection opening for safety pipe

10 Water pipe coupling

11 T-coupling housing

12 Water pipe openings in the T-coupling housing

13 Outlet opening

14 Socket for inner flexible water pipe

15 Leakage outlet

16 Circulation pump

17 water heaters

18 Cold water cooler

19 Spring-biased clamping ring

20 Fixture box cover

21 Wall passage

22 Nipple for corrugated safety pipe

23 Clamping nuts for corrugated safety pipe

24 Stabilization unit 25 Clamping gasket

26 Wall

27 Fixture connection

28 Nipple socket

29 Extraction path

30 O-ring

31 Flange clamp

32 Back side of fixture box

33 Right side of fixture box

34 Left side of fixture box

35 Opposite side of fixture box

36 Fixing nipple for safety pipe 3

37 Fixing sleeve in connection opening 9 for safety pipe

38 Conical part

39 Stop flange

40 Inner fixture box cover

41 Fixture box extension

42 Lower inner edge of the connection opening

43 Inner upper edge of the fixture box at the opening for water outlet 7 or at the wall passage

44 Contact surface on the side of the wall passage 21 opposite the inner upper edge 43 where the water pipe section hits when extracted

45 Rifles

46 Fixture box base

47 Pipe tracks

48 Clutch housing tracks

49 Flange groove

50 Plug flange

51 Expansion opening

52 coupling housing flange

53 Peltier element

54 Pipe extension to the T-coupling housing 11

Claims

1. Sectional coupling (4) for connecting pipe-in-pipe sections (1) each comprising an inner flexible water pipe section (2) and an outer safety pipe section (3), to form a pipe loop for circulating water (5) through a building , where the sectional connection (4) comprises: a waterproof fixture box (6) comprising: a closable opening (7) for a water outlet (8), at least one pair of connection openings (9) for safety pipes (3), and a wall passage (21) with a fixture box cover (20), arranged with 0 - 2 fixture connections (27), at least two safety pipe couplings (22) each for connecting a safety pipe section (3) to respective connection openings (9) in the fixture box (6), at least one water pipe coupling (10) for connecting the internal flexible water pipe sections (2) to adjacent pipe-in-pipe sections (1), where the water pipe coupling (10) is configured to be able to disconnect the internal flexible water pipe sections (2) in the fixture box (6) ), and where the fixture box (6) has a free internal volume comprising the volume between the connection openings (9) and the volume of the wall passage (21) where each of the internal flexible water pipe sections (2) can be pulled through the free volume and out of the wall passage (21) in respective extraction paths (29) where the water pipe sections' bending radius is greater than the minimum permissible bending radius of the water pipe section.

2. Sectional coupling (4) according to claim 1 wherein the sectional coupling is built into a wall.

3. Sectional coupling (4) according to claim 1 wherein the sectional coupling (4) comprises a single fixture box (6a) comprising: a pair of fixture box extensions (41) on opposite sides to accommodate respective extraction paths (29), a connection opening (9) for safety pipes positioned on each fixture box extension (41), wherein respective extraction paths (29) for respective flexible water pipe sections (2) with a given diameter are produced by an inner radius (r) of the pipe being extracted, being pressed against the inner upper edge (43) of the fixture box at the outlet opening (7) and by an outer radius of an arc (R) to the water pipe section (2) which is extracted is pressed against the lower inner edge (42) of the connection opening (9) and a contact surface (44) on the side of the wall passage opposite the inner upper edge 43.

4. Sectional coupling according to claim 1, wherein the sectional coupling (4) comprises a double fixture box (6b) comprising: a pair of connection openings (9) for safety pipes for hot water, and a pair of connection openings (9) for safety pipes for cold water two water pipe couplings (10) for connecting respective inner flexible water pipe sections (2) to respective adjacent pipe-in-pipe sections (1).

5. Sectional coupling according to claim 1, wherein the sectional coupling (4) comprises a 0 - 180 degree fixture box (6c) comprising: a back side (32), a connection opening (9) for safety pipes on a first (33) and a second (34) side on each side of the back side (32), which lies on a common center line L, two connection openings (9) for safety pipes located on an opposite side (35) of the back side (32), and an inner fixture box cover (40) on which the wall passage (21) is attached, wherein the water pipe coupling (10) is a T-coupling with a T-coupling housing (11) comprising two water pipe openings (12) with an essentially 90 degree angle between them and associated sockets (14) with an angle of essentially 45 degrees between an attachment to the flexible water pipe (2) and an attachment to the T-coupling housing (11), wherein the T-coupling housing is shifted towards the back side (32) of the 0 - 180 degree fixture box (6c) so that the aforementioned attachment to the water pipe on the sockets (14) lies along the center line of each connection opening (9), and where the center line M between the two water pipe openings (12) run in the middle between the two connection openings 9 on the opposite side (35), and wherein respective extraction paths (29) for respective flexible water pipes with a given diameter are produced by an inner radius (r) of the pipe being extracted, being pressed against an inner upper edge (43) of the inner fitting lid (40) at the wall passage (21) and by an outer radius (R) of an arc to the water pipe section (2) which is extracted, is pressed against the lower inner edge (42) of the connection opening (9) and a contact surface (44) on the side of the wall passage opposite the inner upper edge 43.

6. Sectional coupling according to claim 1 wherein the water pipe coupling (10) comprises a T-coupling housing (11) comprising two water pipe openings (12) and a socket (14) where the flexible water pipe (2) is attached to an outer end of the socket (14) by a spring-loaded clamping ring (14) and where the socket (14) has a coupling structure at the opposite end of the socket (14) which fits releasably and watertight into a corresponding structure in the T- coupling.

7. Sectional coupling according to claim 6 wherein a socket flange (50) on the respective sockets (14) fits into respective flange grooves (49) in the bottom of the fixture box (6) and wherein the wall passage (21), when screwed down, presses a stabilization unit (24) against the sockets (14) and the T-coupling housing (11) so that the respective socket flanges (50) are held in place in the respective flange grooves (49).

8. Sectional coupling according to claim 6 wherein the water pipe coupling (10) comprises a coupling housing flange (52) at the water pipe opening (12) and where a flange clamp (31) clamps the socket flange (50) on the socket and the coupling housing flange (52) together.

9. Sectional coupling according to claim 6, wherein the water pipe coupling (10) comprises a pipe extension (54) of the T-coupling housing (11) which extends past a fixture connection 27 in the fixture box cover 20 and is connected watertight to this by means of an O-ring (30), where the pipe extension (54) is cut to the correct length after assembly.

10. Pipe-in-pipe circular water supply system wherein a plurality of pipe-in-pipe sections (1) are connected together to form a pipe loop for water by means of sectional connections according to claims 1-10.

11. System according to claim 11, wherein a circulation pump (16) ensures a minimum water flow in the circular water supply system.

12. System according to claim 11 or 12, wherein the circular water supply system comprises a pipe loop for hot water (5b) and a pipe loop for cold water (5a).

13. System according to claim 13, wherein the pipe loop for hot water (5b) goes through a water heater (17).

14. System according to claim 13, wherein the pipe loop for cold water (5a) passes through a cold water heater (18).

15. System according to claim 13 wherein at least one peltier element (53) is connected with a cold side to the pipe loop for cold water 5a and a hot side to the pipe loop for hot water 5b.

15