CONDUIT

TECHNICAL FIELD

The teachings herein relates to a system for generating fluid circulation in a conduit, more specifically to a system allowing easy mounting to existing conduits to provide circulation of fluid in said conduits.

BACKGROUND

In later years, many steps have been taken to achieve higher energy efficiency of hot water systems. One such step is hot water circulation, which is a commonly used technique in newer buildings. Hot water circulation reduces unnecessary drainage of water when opening a hot water tap by making sure that heated water is more or less instantly available at each tap location. Hot water circulation also makes it possible to avoid that any heated water becomes stagnant and cools in the water conduits. Such a hot water system requires a return conduit, which returns the hot water to the heat source from the tap which is located furthest away from the heat source. Many older hot water systems are however of a single conduit type, which does not allow circulation.

By single conduit, it means that hot water is not returned from a tap location in a return conduit to the boiler. However, in larger systems the hot water conduit may be branched of into several hot water conduits. Regardless if the conduit is branched or not, using a single conduit system means that one must allow cold water in the conduit to drain when opening a tap to allow hot water to reach the tap. To modify a single conduit system to a circulation system is often a very large and costly project as a new return conduit must be connected from the most distant tap location to the heat source. It is therefore sought after a way to simplify modification of single conduit systems such that circulation the fluid therein is achieved. SUMMARY

It is an object of the teachings herein to provide a system for generating circulation in a conduit, which alleviates some of the problems with prior art. It is also an object of the teaching herein to use such a system to more rapidly provide heated water from hot water taps in a single conduit hot water system by generating circulation in the hot water conduit. This object is achieved by a concept having the features set forth in the appended independent claims; preferred embodiments thereof being defined in the related dependent claims.

In a first aspect of the teachings herein, a system for generating fluid circulation in a main conduit is provided. The system comprising a pump connected to a main conduit by means of a first conduit and a second conduit. The pump is configured to draw fluid through the first conduit from a first location at the main conduit and to return the fluid through the second conduit to the main conduit at a second location. The first location is downstream of the second location in relation to an intended flow direction in the main conduit. The fluid in the main conduit may thereby be circulated by the provision of the circulation system, which is easy to fit to an existing single conduit system.

In one embodiment of the teachings herein, the second location is in the vicinity of a heating system. Thereby is the water which is heated by the heating system circulated by means of the fluid forces generated by the fluid provided by the pump via the second conduit to the second location in the main conduit.

The first conduit may have a length extending from the pump to the first location such that the first location is at a distance in the main conduit downstream from the second position in the range of approximately 1200 mm to approximately 3000 mm, preferably approximately 2000 mm. The above distance between the first and second location provides spacing between the two to generate sufficient fluid circulation for the absolute majority of applications.

In an embodiment, the first conduit has an outer cross sectional dimension which is significantly smaller the interior cross sectional dimension of the main conduit which it is connected to and wherein the first conduit is configured to essentially extend on the inside of the main conduit. The system thereby uses the already existing conduits to eliminate the need of having to add further external conduits to an existing system.

According to one embodiment, the second conduit delivers fluid in a downstream direction into the main conduit. The fluid forces will thereby increase the circulation from the heat source to opposite ends of the system.

The first and second conduits are preferably connected to a main conduit section and wherein the main conduit section comprises connectors for connection to an existing main conduit. The fluid circulation system is thereby an integrated unit which can be easily connected to an existing system, by simply fitting the existing main conduit with connectors which matches the connectors on the main conduit section.

In one embodiment, the first conduit comprises a first portion connected to the pump and a second portion, and wherein the first and second portions are connected by means of a connector. The second portion of the first conduit may thereby be connected to the first portion during installation of the system to facilitate the installation process.

The first portion of the first conduit may be connected by means of the connector to the second portion of the first conduit inside the main conduit and wherein the second portion is configured to extend inside of the main conduit to the first location.

The second conduit is preferably configured to heat the fluid flowing through the second conduit by allowing the fluid to extract heat from a fluid reservoir connected to the main conduit upstream of the second location.

In an embodiment, the fluid in the second conduit draws heat from the reservoir by means of a heat exchanger through which the second conduit extends, wherein the heat exchanger retrieves heated fluid from the reservoir through a third conduit and returns it to the reservoir by means of a fourth conduit. The fluid in the second conduit is thereby further heated by the heat exchanger, which increases the efficiency of the system.

A first check valve and a shut off valve may be arranged on the third conduit, the first check valve only allowing flow of fluid in the direction towards the heat exchanger, and wherein a second check valve is arranged on the fourth conduit which only allows flow in the direction away from the heat exchanger. Preferably, a check valve is arranged on the second conduit configured to only allow flow of fluid in the second conduit in the direction away from the pump.

In one embodiment, the system further comprises at least one thermometer for detecting a fluid temperature, the thermometer being connected, directly or indirectly, to the pump. The pump may thereby control rate of pumping to manage the temperature of the fluid in the main conduit.

The pump is preferably configured to be able to pump at least 130 liters of fluid per minute.

At least one valve may be arranged in the proximity of the most distant tap location at each branch of the main conduit. The valve allows cold fluid to be removed from the main conduit, and its branches when the main conduit is branched, to decrease the time until hot fluid reaches the most distant tap.

The valve, which may be thermostatically controlled, may be configured to open in order to let cold fluid drain from the main conduit until hot fluid reaches the valve, upon which the valve closes, whereby the system maintains the temperature in the main conduit by providing fluid circulation. The valve can thereby automatically decrease the time from when the system is switched on until hot fluid reaches the most distant tap. The trade-off being that a small amount of fluid is drained and let out into for instance a drain pipe until the hot water reaches the valve.

The valve may be a three-way valve connected between each branch of the main conduit and a drain pipe, which allows the fluid to drain directly into the drain pipe.

In a second aspect, the inventive system is used for providing heated water from hot water taps in a single main conduit hot water system by generating circulation in the hot water main conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the teachings herein will be described in further detail in the following with reference to the accompanying drawings which illustrate non-limiting examples on how the embodiments can be reduced into practice and in which: Fig. 1 shows a system for generating fluid circulation in a conduit according one embodiment,

Fig. 2 shows a system for generating fluid circulation in a conduit according to one embodiment,

Fig. 3 shows an exemplary outline of a hot water system according to one embodiment,

Fig. 4 shows an exemplary outline of a hot water system according to one embodiment,

Fig. 5 shows a perspective view of a system for generating fluid circulation in a conduit according to one embodiment,

Fig. 6 shows an outline of a hot water system in an multi story apartment building according to one embodiment, and

Fig. 7 shows an outline of a tap location according to one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Certain embodiments will now be described more fully hereinafter with reference to the accompanying drawings. Like numbers refer to like elements throughout.

With reference to Fig. 1, a system for generating fluid circulation in a conduit is shown. The system 1 comprises a pump 13 which may be a centrifugal pump or any other pump suitable for pumping fluid, preferably a liquid such as water. Preferably, the pump 13 includes regulation to control the amount of fluid being pumped per time unit and/or a time setting such that it can be controlled to work at certain time periods. The pump 13 has the capacity to pump at least 130 liters of fluid per hour, however larger capacity pumps 13 may also be considered depending on the application.

The pump 13 is connected to a main conduit 3, 18, 23 by means of a first conduit 11 and a second conduit 16, and it is configured to draw fluid through the first conduit 11 from a first location at the main conduit 3, 18, 23 and return the fluid through the second conduit 16 to the main conduit 3, 18, 23 at a second location. The first and second conduits 11, 16 are thereby both connected to a single conduit system shown in the shape of main conduit sections 3, 18 and 23 in Fig. 1. The first location is downstream of the second location in relation to an intended direction of flow in the main conduit 3, 18, 23. The first and second conduits 11, 16 are preferably made out of copper, however other materials are also possible such as stainless steel, plastic or rubber. As is shown in Fig. l, the pump 13 may be connected via the first and second conduits 11, 16 to a main conduit section 18 which in turn may be connectable by means of connectors 17a, 17b to the existing portions 3, 23 of the main conduit 3, 18, 23. The connectors 17a, 17b may be of any type suitable of connecting two sections of conduits (conduits such as a tube or pipe or similar), examples of such are threaded connectors, compressions couplings, solder couplings etc. The main conduit section 18 has a length L in the range of 200 mm to 1000 mm, preferably approximately 400 mm.

The first and second conduits 11, 16 may further comprise shut off valves 12, 15 to allow disassembly of the system if for instance the pump 13 needs to be replaced. The second conduit 16 may further comprise a check valve 14, which only allows fluid to flow in the direction away from the pump 13 towards the second location in the main conduit 3, 18, 23. The second location, i.e. the location of where the second conduit 16 ejects fluid into the main conduit 3, 18, 23, should preferably be located as close to a fluid heating system 2 as possible, the fluid heating system 2 may be an existing fluid heating system 2. Thereby, the heated fluid from the heating system 2 circulated by means of the fluid forces generated by the suction in the first location, i.e. where the first conduit 11 ends inside the main conduit 3, 18, 23, and by means of the fluid forces generated by the ejection of fluid in the second location.

As shown in Fig. 1, the second conduit 16 may be configured to eject fluid into the downstream direction in the main conduit 3, 18, 23. The heating system 2 is in Fig. 1 illustrated by a main conduit 23 onto which is mounted: a heat source 21 for heating cold water flowing in the main conduit 23, a check valve 24 and a safety valve 22. The fluid heating system 2 may however be of any other type and the system for circulation 1 may also be fitted as an alternative to conventional hot water circulation systems during new construction.

To facilitate the installation of the system 1, the first conduit 11 may be constituted by a first portion 11a and a second portion 11c. The first and second portions 11a, 1 lc are connectable by means of a connector 1 lb which may be of any type suitable of connecting two sections of a conduit, examples of such are threaded connectors, compressions couplings, solder couplings etc. The second portion 11c may be configured to connect to the first portion 11a inside of the main conduit 3, 18, 23.

The first conduit 11 has a length extending from the pump 13 to the first location such that the first location is at a distance in the main conduit 3, 18, 23 downstream from the second location in the range of approximately 1200 mm to approximately 3000 mm, preferably approximately 2000 mm. I.e. the distance between first and second locations as measured along a centerline of the main conduit 3, 18, 23 is preferably in the above specified range. Other distances between the first and second locations are however also possible, for instance for extremely long conduits larger distances may be required.

Fig. 2 shows an alternative system for generating fluid circulation in a main conduit 3, 18, 23. As many components of the embodiment in Fig. 2 are already explained in relation to Fig.1, focus will aimed on explaining the components specific to the embodiments in Fig. 2. The system 1 shown in Fig. 2 comprises a pump 13, a first 11 and second 16 conduit connected to the main conduit section 18 and the main conduit section 18 is connected to the existing main conduit 3, 23. The second conduit 16 shown in Fig. 2 is configured to heat the fluid flowing therein before it is ejected into the main conduit 3, 18, 23. This is achieved by the heat exchanger 19 which provides heat to the fluid in the second conduit 16. The heat exchanger 19 may be any conventional fluid to fluid heat exchanger. Other alternatives are also possible such as an electrical heater. The heat exchanger 19 is connected to a reservoir 6 by means of a third conduit 19a and a fourth conduit 19b. The reservoir 6 is connected to the main conduit 23 in a location close to a heat source such that heated fluid is delivered through the reservoir and the reservoir 6 have a volume in the range of 8 to 16 liters.

The heated fluid in the reservoir 6 is then circulated from the reservoir 6 via the third conduit 19a to the heat exchanger 19 and then returned to the reservoir 6 via the fourth conduit 19b. The third and fourth conduit 19a, 19b may also comprise check valve 19c and 19e which only allows fluid flow in the direction specified above, i.e. the check valve 19c will only allow flow of fluid in the direction towards the heat exchanger 19 and check valve 19e arranged on the fourth conduit 19b will only allow flow in the direction away from the heat exchanger 19. The third conduit 19a may also comprise a shut off valve 19d. The system 1 shown in Fig. 2 may provide more effective heating of the fluid circulated by the system 1, and may be suited for use in certain demanding conditions such as for instance very large buildings and/or water systems where additional heat is required.

Fig. 3 shows an outline of a hot water system to which the system for generation circulation 1 is fitted. The circulation system 1 is positioned in the vicinity of the fluid heating system 2 to enable the second location where the fluid is ejected by the pump 13 to be placed as close to the heat source 21 as possible. The system 1 may further comprise a thermometer 4 which detects a temperature in the fluid main conduit, preferably at the tap 5 located most distant from the heating system 2. The thermometer 4 is connected to the pump 13, wire bound or wirelessly and directly or indirectly, such that the pump 13 can control the pump rate in response to the detected temperature. The temperature should preferably not drop below 50°C.

Fig. 4 shows an alternative system for generating fluid circulation in a conduit.

The system 1 shown in Fig. 4 comprises a first conduit 11a, 1 lb, 11c, a pump 13, a second conduit 16 and a main conduit section 18. The pump 13 is connected to the main conduit section 18 via the first 11 and second 16 conduits.

The main conduit section 18 comprises connectors 17a, 17b for connecting to existing conduit portions 3, 23. A check valve 14 is arranged on the second conduit 16 which only allows fluid to flow from the pump 13 in the direction towards the main conduit 18. A check valve 7 is also arranged on the main conduit section 18 which only allows fluid to flow towards the tap locations in the main conduit 3, 18, 23. The system 1 may be configured to be placed in the vicinity of an existing hot water heating system 2, for circulating heated fluid in the main conduit 3, 18, 23.

In Fig. 5, a perspective view of a system for generating circulation in a conduit is shown. The system 1 comprises a first conduit 11, of which the first portion 11a and the connector 1 lb are shown. The system further comprises a pump 13, a second conduit 16 and a main conduit section 18. The pump 13 is connected to the main conduit section 18 via the first 11 and second 16 conduits. A check valve 14 is arranged on the second conduit 16 which only allows fluid to flow from the pump 13 in the direction towards the main conduit 18. Furthermore, shut off valves 12, 15 are arranged on the first 11 and second 16 conduits on either side of the pump 13 to facilitate installation and/or replacement of the pump 13.

Turning to Fig. 6, in which is shown an outline of a hot water system in a multi story apartment building. As is often the case in many larger buildings which has a plurality of apartments, the main conduit 3 is branched of into several branches 31, 32, 33, 34. The branches are thus a part of the single main conduit 3 system and are preferably connected to the same fluid heating system 2. The system is fitted with valves 25 in the proximity of the most distant tap location in each branch 3; 31, 32, 33, 34 of the main hot water conduit 3, i.e. the tap 5 located furthest away from the fluid heating system 2. In this case this means one valve 25 in the proximity of the most distant tap 5 in each top floor apartment 26. It is to be understood that the valve 25 may be fitted to the system 1 when only one branch 3, i.e. a main conduit 3, exists which is often the case in many smaller buildings such as a regular single household houses (which is shown in Fig. 3). Each valve 25 is configured to open when the water is below a threshold temperature. The may thus be thermostatically controlled. Ideally, the threshold temperature is around 50°C. By opening the valve 25, hot fluid will reach the most distant tap location more quickly than without the valve 25. This is however at the cost of having to drain the cool fluid which rests in the main conduit 3 and each of its branches 31, 32, 33, 34. The valve 25 is configured to be closed during normal operation of the pump system 1 when the circulation generated by the pump system 1 keeps the water at a sufficient temperature at all tap locations.

In Fig. 7, a tap location is shown in the shape of a sink 5a with a thereto mounted tap 5 (see Fig. 6). The valve 25 is mounted on the hot water conduit branch 3; 31, 32, 33, 34 below the sink 5a and the valve 25 is connected by a drain conduit 27 to the drain pipe 28. The drain conduit 27 is preferably connected to the drain pipe 28 above the water lock 29. When the fluid in the main conduit branch 3;31, 32, 33, 34 is cold, the valve 25, which may be thermostatically controlled, opens until hot fluid reaches the valve 25. This typically occurs when the pump system 1 has been turned off upon which the temperature of the hot fluid in the conduit 3 and its branches 31, 32, 33, 34 cools down. The valve 25 opens to decrease the time between start up of the system 1 to when hot fluid reaches the most distant tap location on each branch 3; 31, 32, 33, 34 of the main conduit. The valve 25 is preferably a thermostatically controlled three- way valve.

It should be mentioned that the inventive concept is by no means limited to the embodiments described herein, and several modifications are feasible without departing from the scope of the invention as defined in the appended claims. For instance, several systems for generating circulation may be fitted to a single conduit hot water system.