Device for disinfecting a fluid flow in a pipe by means of UV-C radiation

Abstract

Device for disinfecting a fluid in a pipe (1), comprising: a housing (3) adapted to be connected to at least a portion of the pipe (1) and having a longitudinal axis (A); and a source (6) of UV-C radiation housed in a housing (5), wherein the housing (5) comprises at least one lateral wall (5) having a longitudinal section with a curved profile having a concavity facing the interior of the housing.

Description

[0001] Cross-references to related applications

[0002] This patent application claims priority to Italian Patent Application No. 102020000030899, filed on December 15, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to an apparatus for disinfecting fluid flow in pipes via UV-C radiation. Typically, the invention is preferably applied to the disinfection of air in ducts of air conditioning or ventilation systems, as will be mentioned below without loss of generality. Alternative applications include the disinfection of water or other fluids. Background Technology

[0004] During this emergency period related to the Covid-19 pandemic, controlling the spread of the virus through the air is one of the most important tools for reducing the spread of the disease.

[0005] It has been shown that the virus can spread over long distances and for considerable periods of time through the air, usually through aerosols generated by infected individuals coughing, sneezing, and breathing.

[0006] In particular, the transmission of the virus through ventilation ducts has been confirmed; this poses a significant risk factor in all public places (offices, shops, department stores, public transportation) or in private environments with recirculated air.

[0007] The disinfection capabilities of UV radiation are well-known; however, effective UV disinfection systems, especially those operating at wavelengths within the so-called UV-C band (ranging from 250 to 280 nm), require several mJ / cm². 2 The dosage (which varies depending on the microorganisms considered) can only be achieved by using a relatively high-power source and / or a relatively long residence time of air in a confined area subjected to radiation.

[0008] This demonstrates that known systems have significant application limitations. For example, they are not suitable for disinfecting high-flow-rate streams, such as those within ventilation ducts. Summary of the Invention

[0009] The object of the present invention is to manufacture an apparatus for sterilizing fluid flow that does not have the disadvantages of the known and detailed apparatuses described above.

[0010] The aforementioned objective is achieved by the apparatus according to claim 1.

[0011] Due to the curved profile of the device walls, radiation is concentrated within the device itself, thus enhancing the sterilization effect. This allows for the sterilization of large flow rates of fluid. Attached Figure Description

[0012] To better understand the present invention, some preferred embodiments are described below with reference to the accompanying drawings, in which:

[0013] Figure 1 This is a schematic central cross-section of a disinfection device according to a first embodiment of the present invention;

[0014] Figure 2 The device is along Figure 1 The cross section of line II-II in the middle;

[0015] Figure 3 This is a schematic cross-section of the second embodiment of the present invention; and

[0016] Figure 4 It is a cross-section of the device based on the comparative example. Detailed Implementation

[0017] refer to Figure 1 Reference numeral 1 in the figure indicates a ventilation duct along axis A, which includes a disinfection device 2 according to the invention.

[0018] Apart from the central channel 3 that forms the housing for the disinfection device 2, the pipe 1 has a constant cross-section along its entire length, for example, a square of 300×300mm.

[0019] The housing 3 has a wall 5 with a curved profile, which is connected to the corresponding axial end of the planar wall 4 of the pipe 1; in particular, when viewed in a section having a longitudinal plane perpendicular to the wall 5 connected thereto, each wall 5 has a curved profile with a concave surface facing the interior of the housing 3.

[0020] Therefore, the shell 3 has a “convex” shape, which has a square cross-section that varies from the minimum cross-section at the end that coincides with the cross-section of the pipe 1 to the maximum cross-section at the longitudinal centerline of the shell.

[0021] In the example shown, device 2 has an axial length of 0.5m, and the radius of curvature of the wall 5 with a curved profile is constant and equal to 1m; therefore, wall 5 is composed of a cylindrical portion having an axis perpendicular to axis A.

[0022] Pipeline 1 (partially shown) has a total length of 5.5m (including device 2).

[0023] Device 2 includes a UV-C radiation source 6, which in the example shown is composed of a mercury vapor discharge lamp.

[0024] Source 6 has an elongated cylindrical shape with axis B, and in the example shown, it has a length of 240 mm and a radius of 9 mm.

[0025] Example 1 ( Figure 1 and Figure 2 )

[0026] Source 6 is arranged inside parabolic reflector 7 with axis B transverse to pipe 1, and parabolic reflector 7 defines a transverse recess along the center line of wall 4.

[0027] The reflector 7 has a maximum width of 100 mm and a depth of 50 mm, with a minimum radius of curvature of 25 mm at the vertex of the parabola. The portion of the reflector that engages with the wall 5 at its maximum amplitude is positioned 180 mm from axis A.

[0028] The axis of source 6 is located at the focal point of reflector 7 at a distance of approximately 395 mm from the opposite wall 5.

[0029] The inner surfaces of reflector 7, wall 4, and wall 5 are reflective.

[0030] In this disclosure and in the claims, the term "reflection" refers to a surface having a reflectivity greater than 80%.

[0031] In this specific example, the considered reflectivity is 93%. An example of available material is from Alanod GmbH & Co. KG, Germany. UVC.

[0032] Example 2 ( Figure 3 )

[0033] The difference between Example 2 and Example 1 is that the source 6 is arranged inside the housing 3 along the center line of the wall 5 of the device 2.

[0034] Compare Example 1 ( Figure 4 )

[0035] The difference between Example 1 and Examples 1 and 2 is that the wall 5 of device 2 is not curved. Therefore, pipe 1 has a constant square cross-section.

[0036] Source 6 is arranged transversely to pipe 1 near wall 4 of pipe 1 with axis B.

[0037] The reflectivity of the inner wall of pipe 1 is the same as that of Example 1.

[0038] Compare Example 2 ( Figure 4 )

[0039] Comparative Example 2 is the same as Comparative Example 1, but the reflectivity of the inner surface of pipe 1 is low (5%).

[0040] Compare

[0041] To evaluate the performance of the disinfection device 2 according to various examples, the longitudinal mid-sections S1 and S2 of the two detection rectangles were used. Figure 1 , Figure 3 The irradiation is calculated in the two detection rectangles. The longitudinal midsections S1 and S2 are placed along axis A and parallel to axis B of source 6. They have a width equal to the width of pipe 1 (300 mm) and extend in length from the length of individual device 2 (0.5 m) and the entire length of pipe 1 (5.5 m), respectively.

[0042] For ease of comparison, the unity power of the source (1W) is considered.

[0043] For simplicity, it is assumed that the flow in the pipe is laminar with a constant velocity, and that the velocity inside device 2 remains constant even as the area increases. This is a reasonably reasonable and, of course, conservative assumption.

[0044] Then, the total radiated power on cross sections S1 and S2 is detected for each example.

[0045] Finally, the average power on sections S1 and S2 is calculated for each example by dividing the total power by the area of ​​the corresponding cross section.

[0046] The results are summarized in the table below:

[0047]

[0048] The results clearly show that, compared to a pipe with a constant cross-section (Comparative Example 1), using device 2 (Example 2) with curved profile sidewalls essentially doubles the average power density inside the device. This is essentially due to the greater persistence of the beam generated by the source 6 inside device 2. Special attention must be paid to this. Figure 3 The path of the radiation beam in the middle, and Figure 4 Compared to the beam that tends to disperse along the pipe 1, its multiple reflections on the wall 5 tend to keep the beam inside the device 2.

[0049] It is worth noting that in Comparative Example 1, the total power in the detection section S2 exceeds the total power in the section S1 by about 20% (i.e., more than 20% of the power emitted by the source 6 "leaves" the device 2 and is dispersed in the rest of the pipe), while in Example 2, the total power in the detection section S2 exceeds the total power in the section S1 by about 8%, which indicates that the power concentration in the device 2 is greater.

[0050] By comparing Comparative Example 1 and Comparative Example 2 (neither of which is part of the present invention), the contribution of reflectivity can be evaluated when the geometric properties of pipe 1 and source 6 are equal.

[0051] Comparing Example 1 with Example 2, it can be seen that the arrangement of source 2 outside the curved profile of wall 4 and inside reflector 7 allows for an increase of approximately 75% in the power in detection section S1, and allows the difference between the total power in section S2 and the total power in section S1 to be reduced to less than 1%. Therefore, with this solution, the power emitted by source 6 is almost entirely concentrated in device 2.

[0052] To calculate the radiation [mJ / cm] 2 It is sufficient to multiply the average power value described above by the residence time of the flow inside device 2 and pipe 1 (and by the power of source 6, which has been considered as a whole so far).

[0053] Finally, it is obvious that modifications and changes can be made to the described embodiments without departing from the scope of protection defined by the claims.

[0054] In particular, the cross-sections of pipe 1 and device 2 can be circular rather than square; therefore, device 1 can be defined by a continuous annular wall rather than a wall that bends in only one direction.

[0055] The profile of the sidewalls (multiple sidewalls) of device 2 in the longitudinal section can be defined by a curve (e.g., a parabola) with a variable rather than constant radius.

[0056] Source 6 can be of different types and operate at different wavelengths, as long as they are effective in disinfecting microorganisms. For example, it can consist of one or more generally point sources or tubular sources with curved profiles, such as excimer lamps (operating at 222 nm) or LEDs (operating at approximately 275 nm).

[0057] If more irradiance is required, more sources can be used. The sources can be located in their own reflectors or arranged in the same reflector.

[0058] Device 2 can be used to sterilize water (or other liquids) in pipes. In this case, the above advantages are combined with another advantage, namely, due to the convex shape of the wall 5, the liquid slows down in device 2, and thus increases the residence time within the device itself.

Claims

1. An apparatus for disinfecting fluid in a pipeline (1), comprising: The outer casing (3) is adapted to be connected to at least a portion of the pipe (1) and has a longitudinal axis (A); as well as At least one UV-C radiation source (6) is disposed in the outer casing (3). The outer casing (3) has a reflective inner surface and includes at least one sidewall (5) having a longitudinal section with a curved profile having a concave surface facing the interior of the outer casing (3). The outer shell (3) is characterized in that it has a square cross-section and includes four walls (5) having the curved profile in the longitudinal section.

2. The apparatus according to claim 1, wherein, The source (6) is arranged near at least one sidewall (5) of the housing (3).

3. The apparatus according to claim 1, wherein, The source (6) is disposed within a reflector (7), which defines a cavity opening toward the interior of the housing (3).

4. The apparatus according to claim 3, wherein, The reflector (7) defines a recess in the at least one sidewall (5).

5. The apparatus according to claim 1, wherein, The source (6) is a mercury vapor discharge lamp.

6. The apparatus according to claim 1, wherein, The source (6) is an excimer lamp or includes one or more LEDs.

7. The apparatus according to claim 1, wherein, The source (6) is an elongated cylindrical lamp having an axis (B) transverse to the axis (A) of the housing (3).

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