METHOD AND DEVICE FOR IMPROVING THE EFFICIENCY OF TREATING FLUIDS APPLIED TO A UV REACTOR. The present invention relates to method for improving the efficiency of treat ing fluids applied to a UV reactor comprising a longitudinal flow chamber having a longitudinal center axis, an input for entry of fluid in the flow chamber, and an out put for fluid to exit the flow chamber, where at least the input of the flow chamber comprises an inlet pipe followed by an inlet cone which as a part of the flow cham- ber increases the cross section of the channel from the inlet pipe to a cross sec- tion of the longitudinal flow chamber of the UV reactor, said UV reactor having at least one longitudinal UV-lamp parallel to but not coinciding with the longitudinal center axis, and where the UV-lamp is arranged such that fluid can flow along a flow path from the input to the output via the flow chamber, and so that fluid flow- ing along the flow path can be exposed to UV radiation as it flows from the input to the output to receive a UV dose.

The present invention further comprises a UV reactor for treating fluids for use in practicing the method according to the invention. UV irradiation of flowing fluids is undertaken for various purposes. But firstly, it is important to understand that a fluid may take different characters, so as a gas, a vapor or a liquid, the last e.g. to disinfect drinking water and wastewater, and to trigger chemical reactions in a fluid which are enabled by the UV radiation. The UV dosage given to each volume element is always decisive for the de sired effect of the UV radiation in the liquid. In disinfection applications, the micro organisms contained in the water are reliably disinfected only if a specific minimum dosage is applied to them. It is therefore necessary to set the radiation power in the system in such a way that the liquid volume with the lowest accumulated in- tensity reliably receives a Required Minimum Dosage of UV radiation, applying the lowest Specific Power Consumption, in the following pronounced SPC, to the UV reactor. This means that, with a strongly inhomogeneous flow within the UV reactor, some slowly flowing volume elements receive too high dosage, i.e. too much en ergy is expended in this area if the fastest-flowing volume elements are reliably receiving a dosage above the required inimum dosage. A substantial part of the operating costs of a system of this type for disinfecting drinking water is incurred by the power consumption of the UV radiators which are used. Efforts are made to design the flow through a UV reactor of this type to be as even as possible, so that all volume elements receive roughly the same radiation dosage.

Various solutions are proposed for this purpose. Systems exist which com prise elongated UV radiators of the mercury low-pressure radiator type, which are disposed parallel to the flow in the UV reactor. In these systems, the radiation is swirled, for example, by means of baffle plates, in such a way that all liquid vol umes come into the vicinity of the radiators, thereby achieving a substantially even irradiation of the entire flowing liquid. These baffle plates increase the flow re sistance of the system by inducing turbulence, and further the presence of the baf fles will absorb UV light and retain substances and particles occurring in the fluid applied. Particles could possibly be adhered in‘blind current areas’ as sediment, which will reduce the efficiency of the UV reactor, as well as the effect of chemical and physical cleaning systems. Further the use of such UV reactor lead to a not well defined flow profile of the fluid passing the UV reactor, and the presence of turbulence generated by the baffle plates will lead to a larger spread of doses re ceived by each volume element of fluid passing through the UV reactor. A device of this type is presented, for example, in the publication GB 2548379 A.

Another device which in some way seeks to avoid the disadvantages of GB 2548379 A is disclosed in US 2015/0284265 A1 (BORKAR et. al.), in which is de- scribed a reactor for UV sterilization of water from the ballast tank of a marine ves- sel. The reactor comprises an array of UV-C tubes in a pressure vessel with an inlet at one end of the tubes and an outlet at the opposite end. An orifice plate baf- fle is disposed between the inlet and the proximate end of the UV tubes. The tubes are parallel with the longitudinal axis of the vessel. The baffle ensures a more con- centrated UV-C dosage distribution with a smaller population of dosage at both the lower and higher regions.

A different approach consists in the homogenization of the flow within the UV reactor. To do this, static mixers are used to homogenize the speed distribution or

P101 19PCDK00 the speed profile within the flow. A technical solution of this type is presented in the patent document U.S. Pat. No. 7,018,544 B2. It is furthermore dependent on a flow entering in a roughly straight line with a rotationaliy symmetrical speed profile.

An UV reactor consists typically of a reactor chamber of an oblong vessel, comprising an inlet and an outlet. Normally there is an approximately 90 degrees bend in the piping before the inlet to the reactor, and a 90 degree bend/outlet from the reactor, and where the cross section of the vessel typically is larger than the cross section of the inlet and the outlet. Thus, a cone is located at the inlet where the diameter of the flow path is increased and accordingly the velocity of the flow of the fluid applied to the UV reactor is decreased. The reactor chamber comprises at least one UV-light source, for the radiation of the fluid applied to the reactor with UV light, which by a certain wavelength has a killing effect to bacteria and micro organisms. The fluid is applied to the UV reactor at the inlet and passes the UV reactor where the fluid is radiated until it is lead from the reactor via the outlet.

There is following fundamentals:

Fluid: Fluid, as it is meant in this patent application, may take different char- acters, so as a gas, a vapor or a liquid. Thus when the word‘fluid’ is mentioned in the following, it should be understood in its broadest definition, and when particles are mentioned, it may be the molecules of the liquid treated in an UV reactor. Also the fluid may contain particles.

Average Dose (AD): is a theoretical radiation dose in W/m ² , the average in tensity/flux, in the chamber, multiplied with the average residence time in seconds.

Reduction Equivalent Fiuence (REF): Which is the‘practical’ dose defined as the dose corresponding to the average response of all organisms passing the UV reactor receiving a variation of dosages, typically measured by comparing the re- duction level of a single type of organism having passed the chamber to reduction level of the same type of organism having received a precisely defined uniform dose in a !aboratory.

Hydraulic Factor (HF): Which is the ration between the average and the prac tical dose, where the practical REF always will be lower.

P101 19PCDK00 Dose Distribution (DD): The statistical distribution of the radiation dose in par ticles having passed the UV reactor. It is the spread in dose which is preferred to be minimized, as a lower spread leads to a minor difference between AD and REF.

Specific Power Consumption (SPC): The SPC is the necessary electrical power consumption to disinfect 1 nr ⁵ of water in a certain UV Transmission factor by a determined reduction equivalent fiuence.

UV Transmission factor (UVT): A specific property of water related to optical purity defined as the percentage of UV that will be able to travel a defined distance without getting absorbed. Typically measured in percent per 10 mm or percent per 100 mm.

The object of the invention is to minimize the spread of the dose (DD) which will result in a more efficient UV reactor and reduce the SPC.

Another object of the invention is to enable that one and same UV reactor type Is capable of treating fluids with a larger variation of UVT, quality and amount of bacteria or other stuffs in the fluid applied to the UV reactor, e.g. same reactor, same diameter/volume of the UV reactor. This can be achieved by optimizing the Hydraulic Factor (HF).

It is by the invention realized, that this object can be achieved with a method, wherein a UV reactor comprising a longitudinal flow chamber having a longitudinal center axis, an input for entry of fluid in the flow chamber, and an output for fluid to exit the flow chamber, where at least the input of the flow chamber comprises an inlet pipe followed by an inlet cone which as a part of the flow chamber increases the cross section of the channel from the inlet pipe to a cross section of the longi tudinal flow chamber of the UV reactor, said UV reactor having at least one longi tudinal UV-lamp parallel to but not coinciding with the longitudinal center axis, and where the UV-lamp is arranged such that fluid can flow along a flow path from the input to the output via the flow chamber, and so that fluid flowing along the flow- path can be exposed to UV-radiation as it flows from the input to the output to re ceive a UV dose, which is characterized in, that the fluid applied to the UV reactor via the input of the flow chamber is applied a uniform helical flow path when pass-

P101 19PCDK00 ing the inlet cone, in an extent that all particles of the fluid applied to the UV reac tor, within the operation range of the current UV reactor, at least passes at least one UV lamp at a distance to receive at least a prescribed UV radiation dose re lated to the current UV reactor, during passing of the fluid inside the UV reactor.

Hereby the fluid applied to the UV reactor is applied the most uniform helical flow pattern achievable when the fluid passes the UV reactor, which ensures that approximately all the applied fluid to the UV reactor will pass at least one UV source at an adequate distance to receive a certain radiation dose. The helical flow pattern achievable by the reactor according to the invention, and thereby the achievable dose distribution, is significantly more uniform than that the ones known from US 2015/0284265 A1 and GB 254 8379, and further the disad- vantages of the baffles inside the reactor known from US 2017 305 761 A, and GB 254 8379 A, are eliminated.

Further the method according to the invention will result in that the fluid lead into the UV reactor at relative low flows through the UV reactor will adapt the heli cal flow pattern through the flow' chamber of the UV reactor, which will improve the SRC of the UV reactor relative to the known UV reactors, thus increasing the flow interval in w/hich the UV reactor is useable with a satisfying radiation of the fluid. Further will a UV reactor built according to the method according to the invention be able to perform an efficient treatment of fluids containing a higher level of bac teria/microorganisms than the known UV reactors with similar power consumption.

The method according to the invention also includes, that the dose distribu tion of the particles applied to the UV reactor, having passed the UV reactor is characterized in, that any particle has received at least 50%, typically 65% and preferred 75% of the Average Equivalent UV dose (REF).

The choice of phrasing the characterizing part of claim 1 and 2 has been thoroughly considered before filing the application as it in practice is very difficult to express the method otherwise than mentioning some technical features, without limiting the scope of the claims, because there are many co-influencing factors to take in consideration in achieving a prescribed Reduction UV radiation dose in a UV-reactor. Some of the factors are the magnitude of the applied fluid applied to the UV reactor, pressure, the substance of the fluid e.g. viscosity, temperature,

P101 19PCDK00 size of the section of the flow chamber of the UV reactor, the size and configura- tion of the piping leading the fluid to the UV reactor, the necessary flux of the radi- ation from the UV sources, the hydraulic conditions in the inlet cone, and more parameters.

A person skilled in the art will, using the method according to claim 1 and 2, be able to adapt and combine the above factors to achieve a prescribed Reduction UV radiation dose to a fluid, related to a current UV-reactor, during passing of the fluid inside the UV reactor. Putting intervals and figures in the claims would limit the scope of the claims in an unreasonable manner.

A UV reactor for treating fluids, for use in practicing the method according to the invention, comprising a longitudinal flow chamber having a longitudinal axis, an input for entry of fluid in the flow chamber, and an output for fluid to exit the flow chamber, where at least the input of the flow chamber comprises an inlet pipe fol lowed by an inlet cone which as a part of the flow chamber increases the cross section of the channel from the inlet pipe to a cross section of the flow chamber of the UV reactor, said flow chamber having at least one longitudinal UV-lamp paral- lei to but not coinciding with the longitudinal center axis, and where the UV-lamp is arranged such that fluid can flow along a flow path from the input to the output via the flow chamber, and so that fluid flowing along the flow path can be exposed to UV-radiation as it flows from the input to the output, is characterized in, that the inlet cone has a flow guide comprising a number of radial protruding equally curved, turbine blade shaped, guide plates on the reverse side relative to the inlet pipe, said curving turbine blade shaped guide plates being equally distributed over the circular surface of the cone, said guide plates extending between the inlet of the cone and the cone end Hereby is achieved, that the helical flow path of the fluid applied to the UV reactor is applied to the fluid before it enters the flow chamber, as the helical flow pattern is applied the fluid when if passes the cone in the inlet. Thus there will be no baffles, guides etc. inside the flow chamber to which bacteria and microorgan isms might adhere to, and also there will be no blind flow paths in the UV radiation

P101 19PCDK00 chamber of the UV reactor introducing unintended turbulence or collecting sludge and particles occurring in the applied fluid to the UV reactor according to the in vention.

The curving turbine blade shaped guide plates in the UV reactor according to the invention may in some embodiments be attached to the inner wall of the cone.

This may be appropriate in designs for smaller UV reactors according to the invention, but this design might also be usable for designing larger UV reactors.

In another embodiment of the UV reactor according to the invention, suited for separation from the cone, the inlet cone has a flow guide comprising a first somewhat flattish plate shaped ring with a number of radial protruding equally curved, turbine blade shaped, guide plates on the reverse side relative to the inlet pipe, where a plurality of said curving turbine blade shaped guide plates being equally distributed over the circular surface of the first somewhat flattish ring and the cone, said guide plates extending between the first somewhat flattish plate shaped ring at the inlet of the cone and the cone end.

This embodiment is suited for UV reactors with larger capacity, and it is pre ferred that the flow guide is releasable fixed in position in the cone.

To enable static stability of the flow guide, in the UV reactor according to the invention, it is preferred that the flow guide at the end of the inlet cone closest to the reactor chamber comprises a second support ring supporting the radial pro truding equally curved, turbine blade shaped, guide plates.

This will result in that the radial protruding equally curved, turbine blade shaped, guide plates will be supported at each end, which will improve the stability of the flow guide located in the cone.

In a further embodiment where not all the radial protruding equally curved, turbine blade shaped, guide plates are supported/attached to the first somewhat flattish plate shaped ring, it is preferred that the flo guide further comprises a third support ring located between the first somewhat flattish plate shaped ring and

P101 19PCDK00 the second support ring closest to the reactor chamber, supporting the radial pro truding equally curved, turbine blade shaped, guide plates.

This enables for optimizing the uniform helical flow path created by the flow guide in the inlet cone of an UV reactor according to the invention.

To reduce movement of fluid in directions perpendicular to the axis of the in- let to achieve a flow generally more parallel to the axis providing a more symmet rical flow pattern across the turbine and thus a more uniform helical flow inside the flow chamber of the UV reactor, the inlet pipe may comprise a flow rectifier con sisting of at least one plate shaped body located in the inlet tube. The plate shaped body will break some movement of fluid in directions perpendicular to the axis of the inlet, and prepare the fluid for being lead through the flow guide located in the inlet cone of the UV reactor.

In a further embodiment of the UV reactor according to the invention, with the intent to achieve an efficient and improved break of movement of fluid in directions perpendicular to the axis of the inlet before entering the inlet cone with the flow guide, the flow rectifier may comprise a first tube located in the center axis of the inner periphery of the inlet tube, and from the outer periphery of which first tube, one or more plate shaped bodies extends to the inner wall of the inlet tube, said plate shaped bodies being equally mutually angled around the tube, and being attached to the inner wall of the inlet tube.

The presence of a plurality of plate shaped bodies extending between the pe riphery' of the first tube and the inner wall of the inlet tube will break the turbulent flow path in the fluid to be applied to the UV reactor via the inlet cone with the flow guide, and thus lead to a more uniform flow path inside the reactor chamber in the UV reactor.

To enable separation of the flow guide from the UV reactor according to the invention, it is preferred that the first somewhat flatfish plate shaped ring is releas able attached to the flow rectifier.

A precise location of the flow rectifier relative to the flow guide in the UV re- actor according to the invention is important, as to achieve the helical uniform flow path through the reaction chamber, therefore it is preferred that at least one of the

P101 19PCDK00 plate shaped bodies of the flow rectifier comprises a protrusion at the against the first somewhat flattish plate shaped ring adjacent side, extending in direction of the first somewhat flattish plate shaped ring, said protrusion cooperating with a track in the first somewhat flattish plate shaped ring, for positioning of the flow guide rela- tive to the flow rectifier.

Hereby is achieved that the relative position between the flow rectifier in the inlet pipe and the flow guide in the inlet cone always will be correct. This may be of great importance, as the space conditions when re-mounting a flow guide fre- quently are narrow. The presence of the protrusion on one of the plate shaped bodies of the flow rectifier and the cooperating with the track in the first somewhat flattish plate shaped ring will ease the correct positioning of the flow guide relative to the flow rectifier. In a further embodiment of the UV reactor according to the invention it is pre- ferred that the first somewhat flattish plate shaped ring of the flow guide flow guide via some of the curved turbine blade shaped guide plates are connected to a treaded bush cooperating with a treaded bolt lead through the first pipe, said bolt having a head which is in abutment with the reverse end of the said first pipe.

Hereby there is enabled a way to clamp the flow guide in the cone to the flow rectifier in the inlet pipe, and thus this enables for separation of the flow guide from the UV reactor, in terms of service, or exchanging of the flow guide to another type, e.g. with another shape of the blades.

In another embodiment of the UV reactor according to the invention, the flow rectifier may consist of one or more plate shaped bodies oriented transverse to the longitudinal axis of the UV reactor and the inlet pipe, said plates having one or more take outs for passing fluid into the UV reactor.

This embodiment may be usable in special conditions, where the fluid re- quires a special rectification, before it enters the flow guide in the inlet cone.

P101 19PCDK00 It is further preferred that the UV reactor according to the invention comprises a plurality of UV-lamps.

This ensures a more uniform radiation of the fluid applied to the UV reactor chamber subsequent to passing the inlet comprising the flow guide in the inlet cone, and possibly the flow rectifier in the inlet tube.

With the intent to ensure that most of the fluid applied to the reactor is radiat- ed to a prescribed level, it is further preferred that the UV-lamps are arranged at different distances from the longitudinal axis of the flow chamber of UV reactor according to the invention.

Live tests using bacterial spores (Bacillus subtilis) as biodosemeter has shown single UV chambers utilizing the invention to exhibit higher energy efficien cy than present designs across water qualities ranging from drinking water

(UVTI Omm 80-98) to high quality effluent from waste water treatment plants (UVT 70). UV systems incorporating the invention has been demonstrated to have 10- 20% lower specific power consumption (SRC) compared to systems optimized for the point of comparison, and typically an SRC of less than half of the average per formance of competing state of the art systems at point of comparison.

Exemplary embodiments of the present invention are described below with reference to the drawing, in which:

Fig. 1 is a perspective view of a UV reactor with piping according to the in vention,

Fig. 2 shows the same as in fig. 1 , where the piping and the shell of the UV reactor is transparent,

Fig. 3 is a detail perspective view of the inlet of the UV reactor according to the invention,

Fig 4 is an end view of the UV reactor according to the invention shown from the inlet pipe side,

P101 19PCDK00 Fig. 5 is an end view of the UV reactor according to the invention shown from the side of the flow chamber,

Fig 8 is a perspective view seen from the inlet pipe side, of the flow rectifier and the flow guide belonging to the UV reactor according to the invention,

Fig. 7 is a perspective view seen from the flow chamber side, of the flow rec tifier and the flow guide belonging to the UV reactor according to the invention,

Fig 8 is a section side view of the flow rectifier in the inlet pipe and the flow guide the cone between the inlet pipe and the reaction flow/ camber belonging to the UV reactor according to the invention,

Fig. 9 is a perspective view of the UV reactor according to the invention showing the flow pattern of the fluid applied to the UV reactor, inside the inlet pip ing, the flow rectifier, the flow guide in the inlet cone, and in the flow chamber, and Fig. 10 shows distribution profiles of doses received by each volume element passing a reactor according to the present invention compared to a typical com peting reactor.

Fig 1 is a perspective view' of an embodiment of an UV reactor 2 according to the invention comprising a longitudinal flow chamber 4, an input 6 for entry of fluid into the flow chamber 4, an output 8 to exit the fluid from the flow chamber 4. The input 6 comprises an inlet pipe 10, connected with an inlet cone 12, which as a part of the flow' chamber increases the cross section of the channel from the inlet pipe 10 to the cross section of the flow chamber 4. The inlet pipe 10 is connected to piping 14 for leading the fluid to the UV reactor, and the piping 14 shown com prises a bend 16 and a straight pipe 18, and may of course comprise further ele ments which is not shown here.

Fig. 2 and Fig. 3 shows the UV reactor 2 in Fig. 1 , where the piping 14, the input 8, the flow chamber 4 and the output 8 has been made transparent.

The flow chamber 4 comprises a number of oblong UV-lamps 20 extending parallel to the center axis 22 of the UV reactor 2, but in different distances from the center axis, as it clear appears in Fig. 5. The center axis 22 of the UV reactor 2 is also center axis for the inlet cone 12 and the inlet pipe 10.

P101 19PCDK00 At the inside of the inlet cone 12 is located a flow guide 24, and in the inlet pipe 10 is located a flow rectifier 26. Fig. 4 is an end view of the input 6, seen from side of the inlet pipe 10 and shows the flow guide 24 and the flow rectifier 26. The flow guide 24 comprises a number of radial protruding curved turbine blade shaped guide plates 28 (in the following pronounced turbine blades 28) equally distributed over the circular sur face of the cone 12, cf. also Fig. 3. The turbine blades 28 are in the shown e bod- iment of the UV reactor according to the invention, attached to a first somewhat flattish plate shaped ring 30 located closest to the inlet pipe 10 and some of the turbine blades 28 (every second) are further attached to a treaded bush 32 the center axis of which are coinciding with the center axis 22 of the UV reactor 2 and thus for the inlet cone and the inlet pipe 10.

The flow rectifier 28 consists of a first tube 34 the center axis coincides with the center axis of the inlet tube 10. In the shown embodiment of the UV reactor 2 according to the invention, the outer periphery 36 of the first tube 34 comprises 4 plate shaped bodies 38 extending to abutment with the inner wail of the inlet tube 10 Said plate shaped bodies 38 are equally mutually angled around the first tube 34, and having a mutual angle on 90° Cf. Fig. 3 and more clear Fig. 6.

Fig. 5 is an end view of the UV reactor 2 according to the invention shown from the side of the flow chamber 4, wherein the wall of the flow chamber is hid den. As it clearly appears, the UV oblong UV-lamps 20 are arranged in different distances from the center axis 22 of the longitudinal flow chamber 4. Further is shown a second support ring 40, located at the end of the inlet cone 12, closest to the flow chamber 4, said support ring supporting the turbine blades 28. The se cond support ring 40 also appears in Fig. 3 and more clearly in Fig. 6 and Fig 7 Fig 6 is a perspective view seen from the side of the inlet pipe 10, and Fig. 7 is a perspective view seen from the flow chamber side, of the flow rectifier 26 and the flow guide 24 belonging to the UV reactor 2 according to the invention.

P101 19PCDK00 As it appears from Fig 7 and Fig. 8, the flow guide 24 comprises a third sup port ring 42, located between the first somewhat fiattish plate shaped ring 30, and the second support ring 40. The third support ring 42 serves to increase the stabil ity of the turbine blades 28 of the flow guide 24.

As it also appears from Fig. 7 and Fig. 8, the flow rectifier 28 comprises a first tube 34 located in the longitudinal axis 22 of the inner periphery of the inlet pipeI G eg. Fig. 2, from the outer periphery 36 of said first tube 34, one or more plate shaped bodies 38 extends to the inner wall 44 of the inlet pipe 10 (c.f. Fig. 3), said plate shaped bodies 38 being equally mutually angled around the first tube 34, and being attached to the inner wall 44 of the inlet piped 0.

As it further appears from Fig. 7 and Fig. 8 the first somewhat fiattish plate shaped ring 30 of the flow guide 24 is via some of the turbine blades 28 connected to the treaded bush 32 cooperating with a treaded bolt 46 lead through the first tube 34, said bolt 46 having a head 48 which is in abutment with the reverse end 50 of the said first tube 34. Thus, the flow guide 24 and the flow rectifier are mutu- ally connected to each other.

Fig. 8 which is a side section view of the flow rectifier 26, in the inlet pipe 10, and the flow guide 24 in the inlet cone 12, between the inlet pipe 10 and the flow camber 4 belonging to the UV reactor according to the invention, discloses an em bodiment of the connection between the flow guide 24 and the flow rectifier 26. As it appears, the treaded bush 32 is provided with a cap 52 at the end closest to the flow rectifier 26.

Fig. 8 also discloses that one of the plate shaped bodies 38 of the flow recti- fier 26 comprises a protrusion 54 at the against the first somewhat fiattish plate shaped ring 30 adjacent side, extending in direction of the first somewhat fiattish plate shaped ring 30. Said protrusion is cooperating with a track 56 in the first somewhat fiattish plate shaped ring 30, for positioning of the flow guide 24 relative to the flow rectifier 26.

Fig 9 is a perspective view of the UV reactor 2 according to the invention showing a computer calculated flow pattern 58 of the fluid applied to the UV reac-

P101 19PCDK00 tor according to the invention, inside the inlet piping 18, 10, the flow rectifier 26, the flow guide 24 in the inlet cone 12, and in the flow chamber 4.

As it appears, the flow pattern in the fluid having passed the bend 16 is turbu lent, however, the turbulence in the fluid is dampened having passed the flow rec tifier 26, and having passed the flow guide 24 in the inlet cone 12, the flow pattern in the fluid has become uniform and helical. This will enable a more uniform UV- radiation of the bacteria and microorganisms or other particles in the fluid, and en able for a lower consumption of energy per treated m ³ fluid.

Figure 10 shows distribution profiles of doses received by each volume ele ment passing a reactor according to the present invention (curve A) compared to a competing reactor (curve B). Both systems have the same average doses of 40GJ/m2. Due to the invention, the distribution of the new system has a more nar row profile and results in more volume elements receiving close to 400J/m2 com pared to a competing system, where turbulence or lack of exposure of some vol ume elements due to direct passage through a lower intensity area of the chamber causes a wider distribution in the received doses. Figure 10 shows the same dose curves adjusted according to the response curves of a biodosemeter (Bacillus subtilis).

The exponential relationship between dose and actual bacteria reduction results in the effect that doses delivered to volume elements of the traditional systems is further below average compared to those of the present invention has a negative impact on the combined REF and thereby the system performance.

It should be noticed, that the inventor has realized, that the UV reactor ac cording to the invention may take other designs and embodiments than the em bodiment disclosed in the drawings and as specified above, for example could the flow rectifier consist of one or more plate shaped bodies, oriented transverse to the longitudinal center axis of the UV reactor and the inlet pipe, said plates hav- ing one or more take outs for passing fluid into the UV reactor. The attachments of the flow guide in the inlet cone and the connection between the flow guide and the flow rectifier could also take other designs.

P101 19PCDK00

P10119PCDK00 List of position numbers:

2 UV reactor

4 longitudinal flow chamber

6 input

8 output

10 inlet pipe

12 inlet cone

14 piping

16 bend (pipe)

18 straight pipe

20 oblong UV-lamps

22 longitudinal center axis of the UV reactor

24 flow guide

26 flow rectifier

28 radial protruding curved turbine shaped guide plates (turbine plates)

30 first somewhat flattish plate shaped ring

32 treaded bush

34 first tube

36 outer periphery of 34

38 plate shaped bodies (of 26)

40 second support ring for 24

42 third support ring for 24

44 inner wall of 10

46 treaded bolt

48 head of 46

50 reverse end of 34

52 cap on 46

54 protrusion on 38

56 take out in 30

58 flow pattern for the applied fluid in the inlet pipe 10

60 flow pattern for the applied fluid after the flow rectifier 26

62 flow pattern for the applied fluid after the flow guide 24

A distribution profile of dose received by each volume element passing the UV reactor according to invention

B distribution profile of dose received by each volume element passing a competing UV reactor

P101 19PCDK00