In one of its aspects, the present invention relates to a baffle for use in a fluid treatment device. In another one of its aspects, the present invention relates to a method of treating fluid.
Ultraviolet (UV) treatment of water is typically performed by either low pressure or medium pressure mercury-arc lamps emitting either 185 nm to 254 nm wavelength light, depending on the application (e.g., environmental contaminant treatment or disinfection). With either type of lamp, existing UV reactors typically employ regularly shaped baffles to divert flow at or close to lamps. The baffles are solid up to a specific distance from the walls of the reactor.
It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.
It is another object of the present invention to provide a novel baffle.
It is another object of the present invention to provide a novel fluid treatment device.
It is another object of the present invention to provide a novel method for treating a fluid with light.
Accordingly, in one of its aspects, the present invention provides a baffle comprising a continuous outer edge and an interior portion enclosed by the outer edge and connected to the outer edge, wherein the interior portion comprises a plurality of tooth-shaped portions, each tooth-shaped portion comprising: (i) a tip portion directed towards the centre of the baffle, (ii) a base portion adjacent to the outer edge, and (iii) a tooth edge joining the tip portion to the base portion, wherein at least a portion of the tooth edge defines at least a portion of an aperture extending from a first face to a second face of the baffle.
In another of its aspects, the present invention provides a fluid treatment device comprising an inlet for untreated fluid to enter the device, an outlet for treated fluid to exit the device, a housing, one or more light-emitting lamps, and one or more baffles disposed within the housing, at least one baffle of the one or more baffles comprising a continuous outer edge and an interior portion enclosed by the outer edge and connected to the outer edge, wherein the interior portion comprises a plurality of tooth-shaped portions, each tooth-shaped portion comprising: (i) a tip portion directed towards the centre of the baffle, (ii) a base portion adjacent to the outer edge, and (iii) a tooth edge joining the tip portion to the base portion, wherein at least a portion of the tooth edge defines at least a portion of an aperture extending from a first face to a second face of the baffle, and wherein the aperture receives the one or more light-emitting lamps.
In yet another of its aspects, the present invention provides a method of treating a fluide, the method comprising: feeding untreated fluid into the housing of the fluid treatment device defined in the previous paragraph (including its preferred embodiments; passing the untreated fluid through the aperture; and irradiating the untreated fluid with radiation emitted from light-emitting lamp
Thus, the present inventors have recognized that the flow field within a UV reactor system can be modified to match the light intensity field of interest (for example, 254 nm for disinfection or 185 nm for destruction of environmental contaminants).
One preferred embodiment of the present invention is the use of a toothed baffle to approximate an ideal velocity profile of a fluid in a single-lamp flow reactor, a multi-lamp parallel flow reactor, or a multi-lamp cross-flow reactor.
An advantage of implementing the presently described baffle is that reactor efficiency (e.g., dose delivery relative to input power) is increased over existing baffle designs, while power losses due to reactor wall absorption of light are simultaneously minimized by allowing the reactor shell to increase in size. The use of baffles according to the present invention to modify fluid flow in a reactor, in combination with a relatively large reactor shell, can also result in a low head loss arrangement and may outperform existing reactors in terms of delivered dose per unit hydraulic resistance. Other advantages of the invention will become apparent to those of skill in the art upon reviewing the present specification.
Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which:
In one of its aspects, the present invention provides a a baffle comprising a continuous outer edge and an interior portion enclosed by the outer edge and connected to the outer edge, wherein the interior portion comprises a plurality of tooth-shaped portions, each tooth-shaped portion comprising: (i) a tip portion directed towards the centre of the baffle, (ii) a base portion adjacent to the outer edge, and (iii) a tooth edge joining the tip portion to the base portion, wherein at least a portion of the tooth edge defines at least a portion of an aperture extending from a first face to a second face of the baffle. Preferred embodiments of this process may include any one or a combination of any two or more of any of the following features:
In another of its aspects, the present invention relates to a fluid treatment device comprising an inlet for untreated fluid to enter the device, an outlet for treated fluid to exit the device, a housing, one or more light-emitting lamps, and one or more baffles disposed within the housing, at least one baffle of the one or more baffles comprising a continuous outer edge and an interior portion enclosed by the outer edge and connected to the outer edge, wherein the interior portion comprises a plurality of tooth-shaped portions, each tooth-shaped portion comprising: (i) a tip portion directed towards the centre of the baffle, (ii) a base portion adjacent to the outer edge, and (iii) a tooth edge joining the tip portion to the base portion, wherein at least a portion of the tooth edge defines at least a portion of an aperture extending from a first face to a second face of the baffle, and wherein the aperture receives the one or more light-emitting lamps.
Preferred embodiments of this use may include any one or a combination of any two or more of any of the following features:
The device of claim 29 or claim 30 wherein the radial angle of each tooth of the plurality of tooth-shaped portions is substantially the same.
Referring to
Referring to
As shown in
The teeth 110 of the baffle 102 can be formed by any means known to a person skilled in the art. For example, each tooth 110 can be formed from a separate plate which is fastened to the outer edge 118 or to adjacent teeth 110 by one or more welds. Alternatively, teeth 110 of the baffle 102 can be machined as part of a single plate. The number of teeth 110 on a baffle 102 can vary from one tooth 110 to many teeth 110.
In
The distance from the tip 112 to the base 116 (i.e., the length of the tooth) can also vary.
In contrast,
In preferred embodiments, the radial angle of each tooth 110 of the baffle 102 is substantially the same (herein the term “substantially” when used to describe an angle refers to a deviation of)±5°. The radial angle of a tooth 110 is defined as the fraction of the circumference of a circle drawn to include the base 116 as part of the circumference that is occupied by the base 110. For example, where the base 116 is defined by the outer edge 118 of the baffle 102, the radial angle of the tooth 110 is the fraction of the 360 degree perimeter of the baffle 102 which is occupied by the base 116 of the tooth 110. In some embodiments the radial angles of different teeth 110 of the same baffle 102 vary, and/or the radial angles of teeth 110 on different baffles 102 of the same fluid treatment device 104 vary.
In operation, one or more baffles 102 can be disposed in a housing 124 of a fluid treatment device 104 in a manner known to a person skilled in the art. For example, the housing 104 can comprise one or more removable mounting plates 126 (shown in
With respect to the mechanics of operation of a fluid treatment device 104 comprising one or more baffles 102, the toothed design of each baffle 102 allows the flow field of a fluid to be modified to substantially match the light intensity field of interest (e.g., 254 nm for disinfection; 185 nm for destruction of environmental contaminants). This is in contrast to untoothed baffles 2 known in the art (e.g.,
Assuming that fluid particle trajectories are predominantly parallel to the lamp 106, the required retention time t(r) can be defined as a function of radial distance from the lamp:
The ideal velocity profile can be written as:
Substituting t(r) into v(r) gives:
Equation 3 can then be used to define the Ideal Velocity Profile for a single-lamp, annular fluid treatment device.
In practice, the ideal velocity profile is difficult to achieve in real reactors due to wall friction and boundary layer effects which force the velocity at the lamp and the outer wall to diminish to zero. However, CFD simulations have been used to show that the saw-tooth baffle of the present invention can be used to approach closer to the ideal velocity profile as compared to conventional baffles.
For example,
To further demonstrate the principle of operation,
Table 1 shows CFD results for the examples cited above at the same operating conditions. The narrower dose-distribution of the Saw-Tooth Baffle results in improved disinfection performance as indicated by the higher RED value. Table 2 shows a reduced data set if needed to be disclosed in Patent.
Those of skilled in the art will appreciate that it would be possible to employ the above principle of operation for both single and multi-lamp parallel flow reactor configurations.
In the case of multi-lamp reactors,
The following parameters may be varied and tuned to optimize the flow field to match the radiation intensity field within the fluid treatment vessel:
Number of “teeth” or plates
Shape of “teeth” or plates
Size of “teeth” or plates
Porosity
Structural rigidity
The preferred embodiment of the present baffles comprises one or any two or more of the following features:
The present toothed baffle (e.g., saw toothed baffle) in a cross flow reactor can provide an aperature opening that modifies the velocity field such that it provides a velocity gradient that matches the intensity gradients produced by the downsream lamps; the resulting effect is similar to cross flow as in parallel flow lamps. Thus, it is possible to modify the above-described embodiments focussed on parallel to flow lamp orientation to a reactor in which the lamps are transverse (e.g., orthogonal or otherwise angled) with respect to the direct of fluid flow through the reactor. An example of such an approach is illustrated in
While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. For example, reference has been made throughout this specification to tooth-shaped portions. Those of skill in the art will recognize that ‘toothed’, ‘saw-tooth’, ‘fin-shaped’ or ‘petal-shaped’ are equivalent descriptors for “tooth-shaped” portions. It is therefore contemplated that the appended claims will cover any such modifications or embodiments.
All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.
The present application claims the benefit under 35 U.S.C. §119(e) of provisional patent application Ser. No. 62/071,348, filed Sep. 22, 2014, the contents of which are hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2015/050929 | 9/22/2015 | WO | 00 |
Number | Date | Country | |
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62071348 | Sep 2014 | US |