Patent Description:
Hot water tanks are broadly used in domestic applications as thermal and energy storage systems. To achieve high performance during the use of domestic hot water, and better energy and thermal storage capacity, it is necessary to have a highly stratified tank. Hot-water stratified storage tanks are widely known. They serve as far as possible to prevent mixing of hotter and colder water components when loading the storage tank. In this way, heat energy is maintained at the highest possible temperature and thus can be used efficiently.

In this context, stratification is understood as the occurrence and maintenance of adjacent, vertically distributed masses of water of different temperature and density. In a stratified tank, a cold layer of water is present at the bottom of the tank by virtue of its higher density. In the same stratified tank, a hot water layer is present at the top of the water column due to its lower density. These two water layers are separated by a medium temperature middle layer commonly referred to as thermocline.

As is typical of its function, a domestic water tank is subject to introduction and extraction of water. This water, either supplied or extracted, can range from cold to hot. It is particularly advantageous if warm water can be directly introduced within the warm water layer already present within the water tank. This permits, though not limited to, a faster availability of hot water. In a similar way, it is advantageous to introduce cold water within the cold water layer inside the water tank.

A common problem, in particular, during the introduction of water into a water tank is the formation of vortices where and when the water being introduced meets the stationary water inside said tank. These vortices negatively affect the stratification developed inside a water storage tank by promoting the mixing of the different water layers.

It is therefore an important aspect of the performance of a water storage tank that high flow rates into or out of the tank can be attained while mitigating, or preferably, eliminating stratification destroying vortices.

An attempt to address this problem can be found in <CIT>. US '<NUM> discloses a spraying apparatus having fluid storage tank, said tank having an inlet pipe equipped with a diffuser configured to control the fluid momentum in the fluid storage tank.

<CIT> discloses a vortex mitigation element for a water storage tank. Said element is a plate or plate like construction comprising a number of through holes on its surface through which water can flow. This element is presented placed close to the bottom or top of a water tank, such that a hollow is formed by said element and the domed bottom of said tank, wherein, a water inlet/outlet tube is placed. In another embodiment presented in the same document, a perforated box like construction is shown enveloping an inlet tube. In said construction, water flow into the tank is initially disrupted by said box like construction before being discharge in a substantially vertical direction into the water tank. A similar concept and embodiment thereof is presented in patent document <CIT>. In this document, a box like construction is provided which comprises one or more inlet tubes mounted inside said construction. Said tubes are mounted adjacent an in substantial tangential alignment with the perimeter of the box, thereby promoting the circulation of inflowing water along said perimeter. Water is then allowed to exit the box in a substantially vertical direction, though one or more holes mounted on the top and/or bottom of said box.

The abovementioned concepts and embodiments present a disadvantage that should be obvious to those skilled in the art. Said advantage lies in the fact that water exiting any of the abovementioned box like constructions does so in a mostly vertical direction. Said direction, being substantially normal to the boundary area between water zones, has the most potential to create upward/downwards drafts, which will disturb the stratification inside the tank.

<CIT> discloses a concept and multiple embodiments of a diffuser of plate like construction comprising a plate equipped with an approximately centered hole and a second plate mounted substantially parallel and in axial alignment with the first. The hole in the first plate is suitable to receive a water inlet tube, wherein the last section of said tube is oriented substantially perpendicular to the surfaces of both plates. By this concept, mitigation of stratification destroying vortices is attained partially by reducing the flow of water being provided to the tank. Further mitigation of said vortices is attained by the second plate, whereby the momentum of water flowing form the tube is mitigated. In this way, the vortices created by water exiting the end of the tube are mitigated before said water is discharged along the perimeter of the plates. A similar approach is disclosed in <CIT>. In EP '<NUM> a water heater baffle comprising an inlet and an outlet for the passage of water there through, the baffle arrangement forces the water entering the baffle through a labyrinth before exiting the baffle in a direction substantially <NUM>° to its general flow of entry into the baffle.

The aforementioned concept and embodiments thereof permit the exit of water out of the diffuser and into the tank in a substantially horizontal direction. However, and in order to sufficiently mitigate vortices before they exit said diffuser, a large volume inside the diffuser must be provided, resulting in a diffuser of large dimensions. these large dimensions preclude the installation of such a diffuser in smaller tanks, in particular where flow rates are desirable.

The present invention aims to resolve at least some of the problems and disadvantages mentioned above.

The present invention and embodiments thereof serve to provide a solution to one or more of the above-mentioned disadvantages. To this end, the present invention relates to a diffuser for a water tank according to claim <NUM>.

It is an object of the present invention to make available a diffuser which permits, compared to similar diffusers in prior art, minimizing the disturbance to the stratification inside domestic hot water tanks during supply of water.

A more particular object of the invention is to make available a diffuser which, can introduce water as a thin layer adjacent to the top or bottom inner surface of the tank. Furthermore, a more particular object of the invention is to make available a diffuser which can be used in two different connection ways. In this way, water can be supplied to the tank with minimal to no disturbance to stratification inside a said water tank.

It is a particular object of the invention to make available a diffuser comprising a deflecting element suitable for the destruction or at least the mitigation of vortices created by water inflow. It is yet another object of the invention to make available a diffuser in which further includes a shrouding element surrounding said deflection element. In this way, any remaining vortices leaving the deflection element can be further mitigated before leaving the diffuser.

Preferred embodiments of the inventions are presented in claim <NUM> to claim <NUM>. Here, two main embodiments of the invention are disclosed. A first embodiment wherein the diffuser is mounted to a pipe via an inlet on the top of said diffuser. A second embodiment wherein the diffuser is mounted to a pipe via an inlet on the bottom of said diffuser.

According to the invention, a diffuser is made available. Said diffuser comprising a deflecting element shrouded by a bowl. Said bowl and said deflection element, each being provided with a horizontally arranged inlet. The existence of two inlets permits advantageously, multiple manners by which the diffuser can be mounted to a pipe and inside the tank.

The present invention concerns a diffuser (<NUM>) for water tanks as defined in claim <NUM> and a system of a water tank and such a diffuser as defined in claim <NUM>.

In particular, the diffuser (<NUM>) and system of the present invention relate to domestic hot water tanks with a highly stratified water column.

A first aspect of the invention relates to a diffuser (<NUM>) as illustrated in <FIG>. Said diffuser (<NUM>) being configured to receive water having a velocity and for introducing said water near the bottom or the top of a water tank, said diffuser (<NUM>) comprising:.

In the present context, "diffuser" is to be understood as a diffuser mounted and/or extending from a pipe section, and configured to reduce the speed of water admitted into said diffuser, with said water then being discharged from the said diffuser.

As illustrated in <FIG>, the cylindrical deflection element (<NUM>) allows advantageously, a first diffusion stage of the water admitted into the diffuser (<NUM>), changing the direction of flow of said water from a substantially vertical direction into multiple directions radiating from the center of the diffuser (<NUM>). The association of said cylindrical deflection element (<NUM>) with a bowl (<NUM>) provide further advantages by enshrouding the water delivered out of said cylindrical deflection element (<NUM>). In particular, said bowl (<NUM>) permits shrouding vestigial vortices or other forms of turbulence formed at the outlets (<NUM>) of the cylindrical deflection element (<NUM>). More in particular, said shrouding effect isolates said vortices from the water already present inside the tank. In cases where said water inside said tank is already stratified, said shrouding effect reduces or even eliminates any disturbance that may destroy said stratification.

In this context, "turbulence" is defined as a fluid motion characterized by chaotic changes in pressure and flow velocity. Vortices are a major component of a turbulent flow. The terms "vortex" or "vortices" are defined as regions of a fluid in which the flow revolves around an axial line, which line can be either straight or curved. In this context, the terms "stratification" and "stratified" define, respectively, the action and state of separation of a water column into different layers having different temperatures. Each of said layers having a substantially uniform temperature.

<FIG> and <FIG>, each illustrates an embodiment of the invention wherin the circular lid (<NUM>) is equipped with a radial lip and a plurality of radially extending lugs. Said lugs being vertically distanced from said lip, and said lugs being configured to fit the central round hole (<NUM>) of the bowl (<NUM>) or the central round hole (<NUM>) of the cylindrical deflection element (<NUM>). In this way, said lugs are configured to interact with the cutouts (<NUM>) and (<NUM>) in the central round holes of either the bowl (<NUM>) or the cylindrical deflection element (<NUM>), defining a bayonet mount. This permits, advantageously, fast and easy access to the interior of the diffuser (<NUM>), more particularly, to the cylindrical void between the deflection element (<NUM>) and the bowl (<NUM>). In this way, assembly of the diffuser (<NUM>) is made substantially easier, in particular, the manipulation of fasteners contained in the cylindrical void is made easier.

In this context, a "bayonet mount" or "bayonet interface" is defined as a type of mount comprising a cylindrical male element equipped with one or more radially extending elements and one or more female elements equipped with a hole of revolute geometry substantially similar to that of the male element. Said revolute geometry of the female element being interrupted by cutouts, such that the spaces between cutouts form abutments. Said cutouts being configured to accept the radially extending elements of the male element, and said abutments being configured to restrict the longitudinal motion of said radially extending elements.

<FIG> and <FIG> show two different, though not exclusive or limiting, embodiments of the invention, each embodiment representing a mode of attaching the diffuser (<NUM>) to a pipe (<NUM>). <FIG> shows an exploded view of a first preferred embodiment of the invention where the diffuser is configured to be assembled to a pipe (<NUM>) through the top inlet (<NUM>) of the bowl (<NUM>), and by intermediate of a cylindrical pipe (<NUM>). Said cylindrical pipe (<NUM>) being configured to rest against the flat (<NUM>) on the bowl (<NUM>). The same cylindrical pipe (<NUM>) is further configured to accept nut (<NUM>). The top surface of said nut (<NUM>), being configured to rest against the bottom surface of flat (<NUM>), provides the means, when combined with cylindrical pipe (<NUM>) to offer a rigid attachment of pipe (<NUM>) to bowl (<NUM>).

<FIG> illustrates another preferred embodiment of the diffuser (<NUM>). <FIG> shows an exploded view of another preferred embodiment of the invention where diffuser is configured to be assembled to a pipe (<NUM>) through the bottom hole (<NUM>) of the cylindrical deflection element (<NUM>), and by intermediate of a cylindrical pipe (<NUM>). Said cylindrical pipe (<NUM>) being configured to partially enter and extend past inlet (<NUM>). The same cylindrical pipe (<NUM>) is further configured to accept nut (<NUM>). The top surface of said nut (<NUM>), being configured to rest against the inside surface of the cylindrical deflection element (<NUM>), provides the means, when combined with cylindrical pipe (<NUM>) to offer a rigid attachment of pipe (<NUM>) to round cylindrical deflection element (<NUM>).

According to an embodiment of the present invention, the diameter of open side of the bowl (<NUM>) is less than half of the diameter of the tank where it is installed. In this way, water delivered out of the diffuser (<NUM>) is provided with sufficient distance to sufficiently slow down further, thereby reaching the inner walls of the tank at much lower speeds.

According to the invention, the bowl (<NUM>) is flat in the center and domed around the perimeter. In this way, the distance to be traversed by the water before leaving the diffuser (<NUM>) is substantially increased when compared to water leaving a diffuser (<NUM>) with a flat bowl.

According to a further or another embodiment of the invention, the curvature of the dome defines an angle at the edge of the diffuser (<NUM>), said angle being higher than <NUM> degrees with the horizontal plane. Said angle permits dispensing the water coming out of the diffuser (<NUM>) in a more advantageous direction. More preferably, said angle is combined by a smooth curvature of the bowl (<NUM>), thereby allowing the shrouding of vortices while avoiding further turbulence.

According to a further or another embodiment of the invention, the diameter of the cylindrical deflection element (<NUM>) is at least larger than the diameter of the pipe (<NUM>) segment to which it is attached.

According to a further or another embodiment of the invention, the height and diameter of the cylindrical deflection element (<NUM>) are sufficient to attach a pipe (<NUM>) segment and so that the total area of the radial outlets (<NUM>) of said cylindrical deflection element (<NUM>) is larger than the area of the first hole (<NUM>). Preferably, the height and diameter of the cylindrical deflection element (<NUM>) are sufficient so as to permit the assembly of a cylindrical pipe (<NUM>) without reducing the size of said radial outlets (<NUM>).

According to the invention shown in <FIG>, the diameter df of the flat (<NUM>) on the bowl (<NUM>) is identical to the diameter da of a virtual circle of the cylindrical deflection element (<NUM>), which the virtual circle means a circle that is drawn so that all the plurality of vertically extending arms (<NUM>) come in contact with the inside of the circle. In this way, water leaving through the outlets (<NUM>) of the cylindrical deflection element (<NUM>) have a smoother transition towards the edge of the bowl (<NUM>), further reducing turbulence inside the diffuser (<NUM>).

According to a further or another embodiment of the invention, the diffuser (<NUM>) is installed in a substantially vertical orientation and close to the bottom (<NUM>) inner surface of the tank so that the diffuser (<NUM>) is facing the inner surface of said tank. According to a further or another embodiment of the invention, the diffuser (<NUM>) is installed in an upside-down substantially vertical orientation and close to the top inner surface of the tank so that the diffuser (<NUM>) is facing the inner surface of said tank. This permits, advantageously, the introduction of water into a tank is a substantially uniform manner around the diffuser (<NUM>). Furthermore, water is introduced into said tank as a gentle flow following the contour of the bottom (<NUM>) inner walls of the tank. This permits, advantageously, further deceleration of the water flowing out of the diffuser (<NUM>).

According to a further or another embodiment of the invention, the gap between the bowl (<NUM>) and the inner surface of the tank, the flow of water entering the diffuser (<NUM>) and the diameter of the bowl (<NUM>) of the diffuser (<NUM>) are related to each other by means of first constant ratio between c1 and a second constant ratio c2, the value of c1 being between <NUM> and <NUM>, and the value of c2 being equal to <NUM>, the gap (h) being further defined by the two equations: <MAT> <MAT> wherein, Q is the flow in cubic meters per second, h is the gap between the bowl (<NUM>) and the inner surface of the tank, d is the diameter of the diffuser (<NUM>), π is <NUM>, g is the acceleration of gravity in meters per second per second, ρ is the density of the fluid in Kilograms per cubic meter, c<NUM> and c<NUM> are a constant ratios. To provide an optimal rate of the jets to its buoyancy, the value of c<NUM> should be between <NUM> and <NUM>. Preferably the value of c<NUM> is equal to <NUM>. The constant ratio c<NUM> should be between <NUM> and <NUM>, most preferably, c<NUM> is equal to <NUM>. In this way, optimal reduction of the velocity at the outlet of the diffuser (<NUM>) and optimal reduction of vortices can be attained for different water flows and tank dimensions.

According to a further or another embodiment of the invention, the cylindrical pipe (<NUM>) has a plurality of radially extending lugs, said lugs being on the same plane and equally distanced from the lip, and said lugs being closer to the second end of said cylindrical pipe (<NUM>) than said lip, and said lugs being configured to fit the central round hole of the bowl (<NUM>) or the central round hole of the cylindrical deflection element (<NUM>). In this way, the diffuser (<NUM>) can be more easily attached to a pipe and without the need for further fastening elements. This permits, advantageously, providing the diffuser (<NUM>) either as a kit or as a complete assembly. This permits also a faster attachment of the diffuser (<NUM>) to a pipe.

Another aspect of the invention relates to a method for introducing water into a water tank via a diffuser (<NUM>), said water having a velocity, said method comprising the steps of:.

Claim 1:
A diffuser (<NUM>) configured to receive water having a velocity and for introducing said water near the bottom or the top of a water tank, said diffuser (<NUM>) comprising:
a bowl (<NUM>) with a flat center (<NUM>) and domed around the perimeter, the bowl having a first hole (<NUM>) in the center of the bowl (<NUM>);
a cylindrical deflection element (<NUM>) having a first end and a second end, said first end being further equipped with a plurality of extending arms (<NUM>), and said second end being equipped with a second hole (<NUM>);
a circular lid (<NUM>) to be configured to be able to close either the first hole (<NUM>) or the second;
a cylindrical pipe (<NUM>) with a first and second end, said first end being configured to be attached to a pipe (<NUM>), and said second end being equipped with third hole;
wherein the cylindrical deflection element (<NUM>) is, by means of one end of its extending arms (<NUM>), concentrically attached to the inner surface of the bowl (<NUM>);
further characterized in that the cylindrical pipe (<NUM>) is attached to the first hole (<NUM>) of the bowl (<NUM>), the circular lid (<NUM>) is attached to the second hole (<NUM>) of the cylindrical deflection element (<NUM>), or,
the cylindrical pipe (<NUM>) is attached to the second hole (<NUM>) of the cylindrical deflection element (<NUM>), the circular lid (<NUM>) is attached to the first hole (<NUM>) of the bowl (<NUM>), the cylindrical pipe (<NUM>) has, furthermore, a radially extending lip at the first end, and, the radially extending lip is configured to engage with either the first hole (<NUM>) of the bowl (<NUM>) or the second hole (<NUM>) of the cylindrical deflection element (<NUM>), characterized in that
the diameter of the flat (<NUM>) on the bowl (<NUM>) is identical to the diameter of a virtual circle of the cylindrical deflection element (<NUM>), wherein
the virtual circle means a circle that is drawn so that all the plurality of extending arms (<NUM>) are inside of the circle.