NL2027484B1

NL2027484B1 - A fluid disinfection reactor and a method

Info

Publication number: NL2027484B1
Application number: NL2027484A
Authority: NL
Inventors: Arnoud Konijnendijk Edgar; Johannes Wybe Westra Jan
Original assignee: Priva Holding B V
Priority date: 2021-02-03
Filing date: 2021-02-03
Publication date: 2022-09-05
Also published as: WO2022169359A1

Abstract

Title: A ﬂuid disinfection reactor and a method Abstract The invention relates to a ﬂuid disinfection reactor to be ﬂown by a ﬂuid to be disinfected. The reactor comprises a reactor wall defining a reactor channel to be ﬂown by the ﬂuid to be disinfected. Further, the reactor comprises a UV source for emitting UV radiation into the reactor channel and a measuring unit including a UV sensor device that is arranged at a fixed distance from the UV source and facing said UV source for receiving inline UV radiation transmitted through the ﬂuid to be disinfected. The measuring unit is arranged for receiving additional physical data for determining UV radiation transmission through the ﬂuid to be disinfected. Figure 2

Description

P128778NL00 Title: A fluid disinfection reactor and a method The invention relates to a fluid disinfection reactor to be flown by a fluid to be disinfected, comprising a reactor wall defining a reactor channel to be flown by the fluid to be disinfected, the reactor further comprising a UV source for emitting UV radiation into the reactor channel and a measuring unit including a UV sensor device arranged at a fixed distance from the UV source and facing said UV source for receiving inline UV radiation transmitted through the fluid to be disinfected.

Fluid disinfection reactors are typically used for disinfecting water containing nutrients and/or other supplemental additives have passed plant material in a greenhouse.

A known fluid disinfection reactor is provided with an UV source to disinfect fluid flowing through a reactor channel surrounded by a reactor wall. The flow rate of the fluid can be set, e.g. depending on a target disinfection value that is proportional to the ratio of the UV radiation intensity, and the fluid flow rate. Therefore, the known fluid disinfection reactor usually includes an UV sensor aligned with the UV source for monitoring UV radiation intensity after transmission along a fixed distance in the fluid. During operation the UV source, the reactor wall, and/or a UV sensor surface may become filthy. Therefore, accurately monitoring an actual UV radiation intensity is relevant for maintaining the target disinfection value.

An object of the invention therefore is to provide a fluid disinfection reactor wherein the actual UV radiation intensity may be accurately monitored. Thereto, the invention provides a fluid disinfection reactor to be flown by a fluid to be disinfected, comprising a reactor wall defining a reactor channel to be flown by the fluid to be disinfected, the reactor further comprising a UV source for emitting UV radiation into the reactor channel and a measuring unit including a UV sensor device arranged at a fixed distance from the UV source and facing said UV source for receiving inline UV radiation transmitted through the fluid to be disinfected, wherein the measuring unit is arranged for receiving additional physical data for determining UV radiation transmission through the fluid to be disinfected. By using additional physical data for determining UV radiation transmission through the fluid to be disinfected, a more accurate UV radiation measurement can be performed.

Advantageously, a UV sensor device can be used that is sensitive to wide beam UV radiation for receiving inline UV radiation as well as inclined UV radiation.

Here, inline UV radiation includes UV radiation propagating directly from the UV source element to the UV sensor device and UV radiation propagating from the UV source via a single reflection with the reactor wall to the UV sensor device. Further, inclined UV radiation includes UV radiation propagating from the UV source element via multiple reflections to the UV sensor device. Inclined UV radiation data forms additional physical data that may be taken into account for determining UV radiation transmission through the fluid to be disinfected.

The invention is at least partially based on the insight that not only inline UV radiation contributes to the total UV radiation in the reactor channel, but also multiple reflection beams may significantly contribute especially if a reflection parameter of the reactor wall increases in recent reactor designs, e.g. due to new coating materials and/or coating techniques.

In a preferred embodiment, the UV sensor device includes a receiving module protruding into the reactor channel, thereby facilitating receipt of wide beam UV radiation.

The receiving module of the UV sensor device may have, in a cross sectional view, a semi-polygon exterior contour such that the device is made angle sensitive. However, other contour geometries are applicable as well, e.g. a semi-circle.

The receiving module may include a multiple number of radiation guiding elements, such as optical fibers, having respective sensing ends facing to mutually different sensing directions, thereby fur facilitating angle sensitivity. The radiation guiding elements may 1rradiate a corresponding UV sensor element or a single, common UV sensor element converting the radiation into an electric signal.

According to a further aspect of the invention, the received additional physical data may include data from a separate calibration process, thereby further increasing the accuracy of the UV radiation device.

Also, the invention relates to a method of measuring UV radiation emitted from a UV source into a fluid disinfection reactor to be flown by a fluid to be disinfected.

The invention will be further elucidated on the basis of exemplary embodiments which are represented in the drawings. The exemplary embodiments are given by way of non-limitative illustration of the invention. In the drawings: Fig. 1 shows a schematic cross sectional view of a fluid disinfection reactor according to the prior art; Fig. 2 shows a schematic cross sectional view of a fluid disinfection reactor according to the invention; Fig. 3 shows a schematic cross sectional view of a sensor device of a measurement unit provided in the fluid disinfection reactor of Fig. 2; Fig. 4 shows a schematic cross sectional view of another sensor device of a measurement unit provided in the fluid disinfection reactor of Fig. 2, and Fig. 5 shows a flow diagram of a method according to the invention.

In the figures identical or corresponding parts are represented with the same reference numerals. The drawings are only schematic representations of embodiments of the invention, which are given by manner of non-limited examples.

Figure 1 shows a schematic cross sectional view of a fluid disinfection reactor 1 according to the prior art. The known reactor 1 has a tubular shaped reactor wall 2 defining a reactor channel 3 therein to be flown by a fluid to be disinfected, e.g. water containing nutrients and/or other supplemental additives have passed plant material in a greenhouse.

The reactor wall 2 can be made from any suitable material including stainless steel. Further, an interior surface of the reactor wall 2 may be provided with a coating such as a plastic coating e.g. polytetrafluoroethylene or PTFE. The reactor 1 also has an UV source for emitting UV radiation into the reactor channel 3. Typically, the UV source operates in the UVc regime, i.e. at a wavelength between circa 200 nm and 280 nm, e.g. at circa 254 nm so as to disinfect from microorganisms. The UV source includes a rod- shaped UV source element 4 having a mainly disc-shaped cross section. Further, the UV source has a tubular shaped, for UV radiation at least partially transparent housing 5 having a mainly circular cross section and accommodating or embedding the UV source element 4. The transparent housing 5 may be made from quartz, glass or another suitable material. The reactor wall 2, the UV source housing 5 and the UV source element 4 are arranged in a mainly concentric manner. Additionally, the reactor 1 includes a measuring unit 6 including a UV sensor device 7 arranged at a fixed distance from the UV source 4, 5 and facing said UV source 4, 5 for receiving inline UV radiation transmitted through the fluid to be disinfected in the reactor channel 3. Here, the UV sensor device 7 is aligned with an axial center of the reactor channel 3 such that a body axis BA of the UV sensor device 7 intersects a longitudinal axis LA of the UV source element 4. The measuring unit 6 also includes a processor 8 for receiving electric sensor signals from the UV sensor device 7, and an interface 9 providing I/O functionality, power, etc. The UV sensor device 7 has an entrance module 10 facing towards the reactor 3 channel for receiving UV radiation therefrom.

Further, the UV sensor device 7 is equipped with a UV sensor element 11 converting the received UV radiation into an electric signal to be forwarded to the processor. The UV sensor element 11 can be implemented as a semiconductor device such as a CMOS device or CCD device similar to a photodiode sensor. The UV sensor device 7 also includes an annular shaped 5 connection element mounting the device 7 in an opening of the reactor wall

2. The reactor channel 3 has an internal cross sectional diameter D1, while the transparent housing 5 has a cross sectional diameter D2. Further, the fixed distance T between the exterior of the UV source housing 5 and the UV sensor device 7 1s 10 mm.

During operation a fluid to be disinfected flows through the reactor channel 3 of the known reactor 1 shown in Fig. 1. The UV source emits UV radiation into the reactor channel 3 thereby disinfecting the fluid. The flow rate of the fluid flowing through the reactor 1 can be set, e.g. depending on a target disinfection value that is proportional to the ratio of the measured emitted UV radiation, after transmission through 10 mm fluid, also referred to as T10 value, and the flow rate of the fluid. As an example, the flow rate can be set to a lower value if the measured UV radiation intensity reduces, then maintaining a target disinfection value. During operation the transparent UV source housing 5, the reactor wall 2 and/or the UV sensor surface may become filthy. Therefore, monitoring an actual UV radiation intensity is relevant for maintaining the target disinfection value.

The UV sensor device 7 faces the transparent housing 5 of the UV source and receives inline UV radiation transmitted through the fluid in the reactor channel 3. The inline UV radiation includes UV radiation propagating as a direct beam DB directly from the UV source element 4 to the UV sensor device 7, as well as UV radiation propagating from the UV source element 4 backwards as backward beams BB1, BB2 via a single reflection point R1, R2 at the reactor wall 2 as single reflection beams SRB1, SRB2 to the UV sensor device 7, traversing the transparent housing 5 twice in the shown embodiment. Here, two single reflection beams SRB are formed, symmetric relative to the body axis BA of the UV sensor device 7. It is noted that, dependent on a geometry and size of a specific implementation design, the single reflection beams SRB1, SRB2 may traverse the transparent housing 5 only once or not at all.

The combination of the direct beam DB and the single reflection beams SRB1, SRB2 forms the inline beam, also referred to as main beam MB, entering the entrance module 10 of the UV sensor device 7 for conversion into an electric signal, by the UV sensor element 11. Figure 2 shows a schematic cross sectional view of a fluid disinfection reactor 1 according to the invention.

Here, the reactor 1 is the same or similar as the reactor 1 shown in Fig. 1, apart from the aspects described below.

The measurement unit 6 of the reactor 1 shown in Fig. 2 is different from the corresponding one in Fig. 1. Specifically, according to an aspect of the invention, the measurement unit 6 in Fig. 2 is arranged for receiving additional physical data for determining UV radiation transmission through the fluid flowing in the reactor channel 3. In the embodiment shown in Fig. 2, the UV sensor device 7 is sensitive to wide beam UV radiation for receiving both the above described inline UV radiation or direct beam DB as well as inclined UV radiation, explained in more detail below.

Here, the additional physical data includes inclined UV radiation sensed by the sensor device 7. In the shown embodiment, the UV sensor device 7 includes a receiving module 10 protruding into the reactor channel 3, thereby not only receiving the direct beam DB but also radiation propagating from side directions or inclined directions relative to the body axis BA of the UV sensor device 7. The inclined UV radiation includes UV radiation propagating from the UV source element 4 via multiple reflections R3, R4 at the reactor wall 2 as a multiple reflection beam MRB to the UV sensor device 7. Again, two multiple reflection beams SRB are formed, also referred to as side beams SB1, SB2, symmetric relative to the body axis BA of the UV sensor device 7. The combination of the main beam MB and the side beams SB1, SB2 forming a wide beam enter the entrance module 10 of the UV sensor device 7 for conversion into an electric signal, by the UV sensor element 11.

The UV sensor device 7 is sensitive to wide beam UV radiation, at least sensitive to a beam having an inclined angle being less than circa 30° relative to the body axis BA of the UV sensor device 7, preferably having an inclined angle being less than circa 45° relative to the body axis BA of the UV sensor device 7, more preferably having an inclined angle being less than circa 60° relative to the body axis BA of the UV sensor device 7, more preferably having an inclined angle being less than circa 75° relative to the body axis BA of the UV sensor device 7, more preferably having an inclined angle being less than circa 90° relative to the body axis BA of the UV sensor device 7, the UV sensor device 7 then being sensitive to beams that are incident in a 180 ° range or semi-circle or semi-sphere range.

Figure 3 shows a schematic cross sectional view of the sensor device 7 of the measurement unit 6 of the fluid disinfection reactor 1 shown in Fig. 2. The receiving module is, at least for UV radiation, at least partially transparent for receiving the transmitted UV radiation. As shown, the receiving module 10 of the UV sensor device 7 has, in a cross sectional view, a semi-polygon exterior contour 13. In 3D, the exterior surface 13 of the receiving module 10 may include facet segments 14 forming a facet-type semi-sphere like an insect’s eye. However, other geometries are also applicable such as a pyramid type geometry or a semi-sphere.

The receiving module 10 further includes a multiple number of radiation guiding elements or waveguides such as optical fibers 15 each radiation guiding element 15 guiding UV radiation from a sensing end 16 towards a sensor sided end 17, opposite to the sensing end 16. The respective sensing ends 16 are preferably located near mutually different facet elements 14, preferably mainly evenly distributed along the semi- polygon exterior contour or exterior contour 13 of the receiving module 10.

Further, the respective sensing ends 16 of the radiation guiding elements 15 face towards mutually different sensing directions, mainly transverse to the orientation of the respective facet element 14 where the sensing ends 16 are located, for optimal receipt of the UV radiation.

The UV sensor device 7 shown in Fig. 3 includes a single UV sensor element 11 for converting UV radiation received from the multiple number of radiation guiding elements 15, in particular from the sensor sided end 17 thereof, into an electric sensor signal. The UV radiation from the radiation guiding elements 15 is combined in a composed UV radiation output of the individual radiation guiding elements 15. The contribution of the individual radiation guiding elements 15 can be uniform or weighed depending on their facing direction so as to enable an angle sensitivity. Individual facet elements 14 may be selected to have a radiation transmission attenuation depending on a desired weigh factor relative to the other fact elements 14.

Figure 4 shows a schematic cross sectional view of another sensor device 7 of the measurement unit 6 of the fluid disinfection reactor 1 shown in Fig. 2. Here, the UV sensor device 7 includes a multiple number of UV sensor elements 11a-e for converting UV radiation received from a respective radiation guiding element 15 of the multiple number of radiation guiding elements 15 into respective electric sensor signals that can be processed by the processor 8 of the measuring unit 6, either uniform or in a weighed manner.

The processor 8 may be arranged for determining a total amount of UV radiation emitted in the reactor channel 3, based on sensor data from the UV sensor device 7, optionally further based on model parameters of the geometry and/or dimensions of the reactor channel 3 and/or other parameters such as reflection parameters of materials in individual components of the reactor 1, thereby providing a so-called soft sensor.

Optionally, the processor 8 is arranged for compensating the sensor data from the UV sensor device 7 if the fixed distance T between the UV source 4, and the UV sensor device 7 is less than or more than 10 mm.

The processor 8 may further be arranged for receiving additional 5 physical data from a separate calibration process that is performed for measuring an amount of UV radiation emitted in the reactor channel 3. The additional physical data may be provided to the processor 8 via the interface 9 providing I/O functionality, power etc., either wired or wireless.

As an example, the separate calibration process can be performed by mixing an known amount of UV reactive agent such as iron chelate to the fluid to be disinfected, then flowing the fluid through the reactor channel 3 while exposing the fluid to the emitted UV radiation, and after passing the UV source, determining an amount of the original UV reactive agent and/or a reacted agent.

Then, a computational model based on the transmitted UV radiation sensed by the UV sensor device 7 can be validated and/or calibrated using the processor 8 of the measurement unit.

Other calibration measurements can be performed and used as additional physical data for feeding the processor 8, e.g. using an additional UV radiation sensor device.

Figure 5 shows a flow chart of a method 100 of measuring UV radiation emitted from a UV source into a fluid disinfection reactor to be flown by a fluid to be disinfected.

Particularly, the method 100 includes a step of receiving inline UV radiation data 110 transmitted through the fluid to be disinfected, and step of receiving additional physical data 120 for determining UV radiation transmission through the fluid to be disinfected.

The further physical data may include inclined UV radiation received by a UV sensor device and/or data from a separate calibration process.

The separate calibration process may include a step of mixing the fluid to be disinfected with a UV reactive agent and a step of determining an amount of the UV reactive agent after passing the UV source.

Various variations are possible.

As an example, the reactor wall 2 may be substantially tubular shaped or may have another geometry such as a sphere.

Also the UV source 4, 5 may be substantially tubular shaped, arranged mainly concentric relative to the reactor wall 2, or have another geometry or orientation, e.g. placed eccentric relative to the reactor wall 2. It is noted that the measurement unit 6 can be implemented as a single device including both the processor 8 and the UV sensor device 7. However, alternatively, the processor 8 can be located on a remote location, while enabling data communication with the UV sensor device 7, either wired or wireless.

It is further noted that the idea of using data from a separate calibration process may be used in combination with a reactor provided with a US sensor device having a receiving module 10 protruding into the reactor channel 3, as shown in Fig. 2, or more generally in combination with another reactor type, e.g. as shown in Fig. 1. Then, according to an aspect of the invention, a fluid disinfection reactor to be flown by a fluid to be disinfected is provided, comprising a reactor wall defining a reactor channel to be flown by the fluid to be disinfected, the reactor further comprising a UV source for emitting UV radiation into the reactor channel and a measuring unit including a UV sensor device arranged at a fixed distance from the UV source and facing said UV source for receiving inline UV radiation transmitted through the fluid to be disinfected, wherein the measuring unit is arranged for receiving additional physical data for determining UV radiation transmission through the fluid to be disinfected, wherein the measuring unit includes a processing unit for receiving an electric sensor signal from the UV sensor device disinfection reactor, and wherein the processing unit is arranged for receiving additional physical data from a separate calibration process.

It will be clear to the skilled person that the invention is not limited to the exemplary embodiment represented here.

Many variations are possible.

Such variations shall be clear to the skilled person and are considered to fall within the scope of the invention as defined in the appended claims.

Claims

Conclusions

A fluid disinfection reactor to be flowed through by a fluid to be disinfected, comprising a reactor wall defining a reactor channel to be flowed through by the fluid to be disinfected, the reactor further comprising a UV source for emitting UV radiation into the reactor channel and a measuring unit comprising a UV sensor device arranged at a fixed distance from the UV source and facing said UV source for receiving in-line UV radiation transmitted through the fluid to be disinfected, the measuring unit being arranged to receive additional physical data for determining UV radiation transfer through the fluid to be disinfected.

The fluid disinfection reactor of claim 1, wherein the UV sensor device is sensitive to wide beam UV radiation to receive in-line UV radiation and diffracted UV radiation.

The fluid disinfection reactor of claim 2, wherein the additional physical data comprises diffracted UV radiation sensed by the sensor device.

The fluid disinfection reactor of claim 2 or 3, wherein the in-line UV radiation comprises UV radiation propagating directly from the UV source element to the UV sensor device and UV radiation propagating from the UV source via a single reflection with the reactor wall propagated to the UV sensor device.

A fluid disinfection reactor according to any one of claims 2-4, wherein the diffracted UV radiation comprises UV radiation propagating from the UV source element via multiple reflections to the UV sensor device.

A fluid disinfection reactor according to any one of the preceding claims, wherein the UV sensor device comprises a receiving module projecting into the reactor channel.

A fluid disinfection reactor according to claim 6, wherein the receiving module of the UV sensor device has, in a cross-sectional view, a semi-polygon outer contour.

Fluid disinfection reactor according to claim 6 or 7, wherein the receiving module comprises a plurality of radiation guiding elements with respective measuring ends facing mutually different observation directions.

The fluid disinfection reactor of claim 8, wherein the UV sensor device comprises a single UV sensor element for converting UV radiation received from the plurality of radiation guiding elements into an electrical sensor signal.

The fluid disinfection reactor of claim 8, wherein the UV sensor device comprises a plurality of UV sensor elements for converting UV radiation received from a respective radiation conduction element of the plurality of radiation conduction elements into respective electrical sensor signals.

A fluid disinfection reactor according to any one of the preceding claims, wherein the reactor wall is substantially tubular.

A fluid disinfection reactor according to any one of the preceding claims, wherein the UV source is substantially tubular, arranged substantially concentrically with respect to the reactor wall.

A fluid disinfection reactor according to any one of the preceding claims, wherein the measuring unit comprises a processing unit for receiving an electrical sensor signal from the UV sensor device.

A fluid disinfection reactor according to claim 13, wherein the processing unit is adapted to receive additional physical data from a separate calibration process.

A method for measuring UV radiation emitted from a UV source in a fluid disinfection reactor which is flowed through by a fluid to be disinfected, the method comprising the steps of: - receiving in-line transmitted UV radiation data by the fluid to be disinfected, and - receiving additional physical data for determining UV radiation transfer through the fluid to be disinfected.

The method of claim 15, wherein the further physical data comprises diffracted UV radiation received by a UV sensor device.

A method according to claim 15 or 16, wherein the further physical data comprises data from a separate calibration process.

The method of claim 17, wherein the separate calibration process comprises a step of mixing the fluid to be disinfected with a UV-reactive agent and a step of determining an amount of the UV-reactive agent after passing through the UV -source.

The method of any preceding claim, further comprising a step of determining a total amount of UV radiation emitted into the reactor channel based on the received in-line UV radiation data and the received additional physical data.