Patent Application
20240228331
This invention relates to a method and apparatus for treating a liquid using radiation.
Systems employing UV light bulbs sources provided in quartz tubes within a flow of liquid to be treated are widely employed. Any system where the ultraviolet radiation source(s) is submerged in the liquid has electrical connection and associated waterproofing complexities.
Systems employing UV radiation typically convey flow through a conduit in which multiple UV bulbs are installed, if a bulb fails then either the entire flow through the unit must be ceased or the flow will continue at a reduced UV dose until an operator can respond and replace the bulb. A reduced UV dose reduces the UV treatment efficiency of the system. Alternatively, there needs to be additional redundancy built into the system which is on standby in case of bulb failure.
While some systems incorporate automatic wiping systems for the outside of quartz sleeves, from time to time operators need to access areas of a treatment system for a manual clean and other maintenance. In some existing systems that use open channels, in order to change a bulb or to undertake a manual clean of the quartz tubes a whole bulb and quartz tube assembly along with the power leads and supporting frame sometimes need to be disconnected and lifted out, dripping and wet. Alternatively in a pressurised system, to access the outer surface of the quartz tubes for a manual clean the system must be stopped, drained, and then the tubes removed from the system. In both cases this is inconvenient and time-consuming. The quartz tubes are long and reasonably delicate. Moving racks of bulbs/quartz sleeves out of a channel or extracting these one by one from a pressurized system creates the risk of breakage. Furthermore, it may also be unhygienic and messy with liquids such as wastewater effluents dripping onto surroundings and/or getting onto operators which is a health hazard and is unpleasant.
The various issues and complexities discussed above add to the cost and difficulty of constructing and maintaining many prior art systems.
To achieve an acceptable degree of treatment of a liquid, a suitable dose of UV radiation must be delivered to the liquid. The dose is defined as the product of the radiation intensity and the duration for which the liquid is exposed to the radiation, which is also known as the retention time.
When using radiation to treat liquids, it is important to note that the liquid may contain material that discolours, obscures, or otherwise reduces the transmissibility of the radiation through the liquid. For example, even seemingly clear liquids like Sprite™ or white wine can also have low ultraviolet light transmissivity (UVT) due to their dissolved solids. Low transmissivity reduces the radiation available for treatment within the liquid and decreases the effectiveness of treatment.
Many prior art systems are incapable of providing viable (in terms of cost and/or treatment effectiveness) treatment to fluids of low UVT and, for example, specify that the UVT needs to be approximately 60% or higher.
Other prior art systems aim to treat lower UVT liquids by the provision of increased radiation input per unit of flow but this results in higher costs.
Some prior art aims to reduce the depth of the fluid being irradiated by creating a thin flow/film. This may reduce the high transmission losses of the radiation that occurs in low UVT liquids. However, systems with thinner flows typically have lower flow throughput than systems with thicker flows.
Treating supercritical flow with radiation has advantages however experimental testing has revealed that triggering supercritical flow from a sluice gate or slot out into a conduit can result in intermittent elements of liquid ejecting upwards from the supercritical flow in the conduit. While this is a relatively minor effect over a short period of operation for example minutes to hours by contrast over an extended period of operation for example days to weeks this can result in an undesirable amount of fouling of any radiation source, reflectors or radiation transmissive window in close proximity.
Another flow treatment system is known from WO2017111616, the contents of which is incorporated herein by reference.
According to one example there is provided an apparatus for treating a liquid, the apparatus including:
According to another example there is provided a method of treating a liquid including:
According to another example there is provided an apparatus for treating a liquid, the apparatus including:
According to another example there is provided an apparatus for treating a liquid, the apparatus having a frame and one or more treatment module(s) where each module includes:
According to another example there is provided a method of operating a liquid treatment apparatus, the apparatus including a plurality of liquid treatment modules, wherein the apparatus is configured to treat a plurality of separate flows of liquid through respective separate ones of the liquid treatment modules,
wherein each liquid treatment module has one or more radiation source(s) for treating the liquid flowing through one or more conduit(s) of that module and wherein at least one of the treatment modules is movable and has an opening lid, the method comprising:
According to another example there is provided a method of operating a liquid treatment apparatus, the apparatus including a frame and one or more liquid treatment modules, each module including: a liquid inlet for receiving liquid from a liquid source; a liquid outlet for discharging liquid to a liquid drain; one or more liquid conduits between the liquid inlet and the liquid outlet; and one or more radiation sources for treating the liquid in that module; wherein the method comprises:
According to another example there is provided a liquid treatment module comprising:
According to another example there is provided a liquid treatment apparatus including:
According to another example there is provided a liquid treatment apparatus including:
In some examples the conduit is an open channel.
Examples may be implemented according to any of the dependent claim 2-31, 33-38, 40-45, 47-63, 65-79, 81-94, 96-110, 112-131 or 133-145.
It is acknowledged that the terms “comprise”, “comprises” and “comprising” may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, these terms are intended to have an inclusive meaning—i.e., they will be taken to mean an inclusion of the listed components which the use directly references, and possibly also of other non-specified components or elements.
Reference to any document in this specification does not constitute an admission that it is prior art, validly combinable with other documents or that it forms part of the common general knowledge.
The accompanying drawings which are incorporated in and constitute part of the specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of embodiments given below, serve to explain the principles of the invention.
The invention will be described by way of examples employing ultraviolet (UV) radiation but it is to be appreciated that in appropriate circumstances that other forms of radiation may be employed. The invention will also be described by way of examples employing quartz but it is to be appreciated that in appropriate circumstances that other forms of material that are transmissive to radiation may be employed.
The channel 24 that the liquid flows in is enclosed by a bottom face and side faces, leaving the top face open, or at least not in contact with the liquid. This type of liquid flow within a conduit with a free (unconstrained) liquid surface is known as “open channel flow”. The open channel design allows the arrangement of one or more ultraviolet radiation sources 25 above the open top face of the channel. In some examples, a channel, or module with one or more channels/conduits, with a width of 1 m or less may be particularly well suited for enabling practical access into channels or modules that have a lid attached. In some examples a channel or conduit having a depth of 100 mm or less may be particularly well suited to systems used in a frame or rack or in a smaller-scale treatment system which has lower flow throughput requirements, for example for treating milk or beverages. In other examples, greater widths and/or depths may be used.
The gate 23 creates an opening in the form of a slot between the gate and base of the channel 24. This allows a flow 26 of liquid to flow out of the source 22. Various different slot heights, producing various different flow thicknesses, may be useful for different applications.
In some applications, there are advantages to using a slot height of about 6 mm or greater or about 7 mm or greater to produce a flow thickness of about 6 mm or greater or about 7 mm or greater. Thicker flows may require less pressure or energy to move the liquid through the treatment apparatus. This advantage would increase as flow rates increased. It may also have the advantage of reducing or avoiding the chance of partial blockages of the slot, or other type of opening, where the liquid enters the flow conduit. Any such blockages can cause flow disturbances and splashing when operating a system with a supercritical flow that potentially fouls internal parts of the apparatus such as a quartz window or bulbs, etc. Blockages may be particularly likely when the liquid contains or is contaminated with small solids, for example crop residues in vegetable-processing effluent; or debris (such as a duck feather or pine needle, etc) that fall into upstream wastewater treatment units. Smaller slots may be more prone to blockages than larger ones and may require screens upstream of the slot to remove debris and other solids. Larger slots may avoid the need for such screens or increase the suitable mesh size for such screens, thereby reducing their resistance to fluid flow.
A high velocity flow of a liquid may be created by storing the liquid in a reservoir as shown in
It has been found that to achieve a high throughput whilst ensuring adequate treatment that a supercritical flow can be employed. A supercritical flow is a rapid and shallow flow through an open channel (as opposed to constrained, pressurised flow also sometimes known as “pipe” flow) and is defined as set out below.
The Froude Number of a flow is defined as:
By definition, Fr must be greater than 1 for a flow to be in a supercritical state.
By manipulating the Froude Number equation, v=Fr√{square root over (yg)}
Since Fr>1 in a supercritical flow, for a depth of flow y the flow velocity for having a supercritical flow must be:
Given a depth for the flow 26, for example as set at a gate or slot, it is possible to calculate the flow velocity required (and flowrate throughput) so that supercritical flow conditions prevail.
Supercritical flows with high velocities are often turbulent. In experiments comparing supercritical laminar flow against supercritical turbulent flow, the treatment performance was superior for turbulent flow.
Once the flow 26 flows through the gate 23, the treatment process begins. The ultraviolet radiation sources 25 may be a plurality of tubular ultraviolet light bulbs with reflectors to direct as much of the radiation into the liquid to be treated as possible.
The apparatus 21 of
In this apparatus 21, the gate 23 can have a slot of 6 mm or greater, for example 7 mm or greater.
The intensity of radiation, such as UV light, decreases exponentially as it penetrates into a liquid. It may be expected that treatment (as measured by reduction in contaminant count due to the treatment) would decrease with increasing liquid thickness (depth). For example, in experiments using irradiation of supercritical flow both orange juice and apple juice diluted to a UV transmissivity (UVT) of 0.2% were treated more effectively at a thickness of 2 mm than at a thickness 4 mm (depth measured at the entry point to the supercritical flow channel). In these experiments treatment efficiency continued to decrease as the liquid flow thickness further increased. Similar results have been observed for other liquids including effluents.
However, it has now been found that in some cases better than expected results may be achieved when treating supercritical flows that are thicker than this. For example, in further tests of the orange and apple juices, it was found that when the UVT was improved to 25% by further dilution more efficient treatment was often obtained for thicknesses of 4 mm and 6 mm as compared to 2 mm. In other testing on an effluent (UVT of 22%) depths of 8 mm and 10 mm were found to be superior to 2 mm and 3 mm.
Without intending to be bound by theory, it is possible that in some of the examples above, at low UVTs the majority of the radiation is fully absorbed into the liquid at the thicknesses tested, but at higher UVTs a significant amount of the radiation might pass into the liquid, reflect off the base and then leave the liquid after which would it then be subjected to further inefficient reflection/transmission losses in the lid above the treatment channel. However, in these higher UVT cases as the liquid thickness increases, more of the radiation would be absorbed and not leave the liquid.
However, it appears that the factors involved are more complex than can be explained by a simple relationship to UVT alone. In experimental testing of a liquid with a UVT of 2.5%, it was found 7 mm achieved slightly better treatment than 3 mm whereas for testing on apple juice diluted to a very similar 2% UVT, the more normal expectation still held true with 2 mm being better than 4 mm, 4 mm being better than 6 mm and 6 mm being better than 8 mm, etc.
The factors that affect treatment are multiple and complex. For example, while the concentration of solids in a liquid are known to affect UVT and treatment, it also depends on the nature of the solids. For example, solids which enable bacteria to be shielded within their bodies are harder to treat than liquids where bacteria are restricted to the outside of the solids. Because the various factors that affect treatment are multiple and complex, a simple measure of UVT cannot be used to predict when larger flow thicknesses are viable. However, this can instead be simply determined by site-specific testing.
Being able to effectively treat thicker supercritical flows of suitable liquids has multiple advantages. It may allow adequate treatment to be achieved at higher flow rates, or more thorough treatment at a similar flow rates. Using thicker flows also reduces the chance of blockages occurring in the inlet because of the greater slot height used.
Supercritical flows having thicknesses y of 6 mm or greater can be achieved by ensuring that the velocity v of the flow is great enough that the Froude number Fr is greater than 1 for the given thickness y.
Reflectors (not shown in
In some examples, a plurality of apparatuses 21 can be provided as modules within a larger treatment apparatus. For example, the apparatuses 21 can be stacked on each other or supported by a frame. The apparatuses can be fluidly connected in parallel so that liquid flowing through each module forms a separate flow from liquid flowing through the other modules.
The modules 14a-14h can be configured to support open channel flow through their respective conduits 29 in which the upper surface of the liquid is not constrained by e.g. a top wall. The modules 14a-14h can be configured to support supercritical flow through their respective conduits 29. Alternatively, the modules 14a-14h can be configured to support any other type of open channel flow hydraulics including critical flow or sub-critical flow or alternatively the conduits 29 can be enclosed at the top and fully filled with the liquid flowing through under pressure.
The modules 14a-14h can be arranged to operate in parallel to each other, i.e. they provide separated flow paths for separate portions of the liquid. While the flows are parallel in a fluid flow sense, they need not be parallel in a geometric sense and can be at various angles to each other. The liquid flows through the apparatus 12 in a plurality of separate flows, each of the separate flows through separate modules. The flows may be split into separate flows by a flow separator constructed as part of the apparatus 12 or the apparatus 12 could receive flows that are already separate from each other, e.g. from separate supply hoses.
Each module 14a-14h can be connected to a liquid supply via a respective one of the inlets 15a-15h. Each inlet receives flow and then distributes and discharges it through a slot(s) into its module's respective conduit(s). In the example of
The modules 14a-14h may be connected to a common liquid supply or to different liquid supplies. Liquid enters the modules 14a-14h through the inlets 15a-15h then flows through one or more conduit(s) (indicated at 29 in
The liquid inlets 15a-15h can be connected to flexible inlet conduits such as hoses 31 (only one shown for clarity). In other examples concertina conduits or telescoping conduits could be used in place of the flexible inlet conduit. Alternatively, the liquid inlet could be slidably or pivotably connected to the liquid source to remain connected while moving. In the example including hoses, when the modules are moved the hoses from the liquid source can simply flex to permit the movement while maintaining a liquid-tight connection to the modules.
Liquid exits the modules 14a-14h via gaps into respective outlets (the gaps 42 of one module 14f are shown in
As shown in
In the example shown in
In other examples, a separate drain can be provided for each module in place of the common drain 18 of
The construction of the apparatus 12 allows the modules to be moved and accessed without having to be disconnected first. This prevents liquid from dripping from the apparatus 12 or liquid supply when the modules are moved, avoiding mess and potential contamination.
It will be appreciated that the liquid source and liquid drain connections of the module that allow it to be moved without disconnection or dripping could be applied to a treatment apparatus with only one treatment module, as well as one with a plurality of modules as in the example shown in
In the example of
A cover may be provided over the end of each recess 19a-19d in the region 34 generally indicated at the end of recess 19d. This may block radiation from exiting the apparatus 12 via the recesses 19a-19d. In one example, the cover may be a metal flap. The metal flap may be hinged to the body of the liquid drain 18 near the respective recess so that it can be pushed open by the module when the module is pulled out and hinge closed when the module is pushed back in.
In the state of the apparatus 12 shown in
The radiation sources (e.g. UV bulbs 28) can be located in the lid 17. The lid 17 can also have reflectors 32 associated with the UV bulbs 28. One or more windows (not depicted with solid lines due to its transparency, but generally indicated by the arrow 30) made of a radiation-transmissive material can be provided on the lid 17. The radiation-transmissive material can be selected to allow at least some of the wavelengths of radiation produced by the radiation source to pass through to the liquid without major attenuation. For example, when the radiation sources are UV sources the window can be made of a UV-transmissive material. The window 30 may be made of quartz, which allows UV radiation to pass through largely unattenuated. In other examples, the window 30 could be made of other materials such as UV-transmissive plastic, for example Perfluoroalkoxy alkanes (PFA); Ethylene Tetrafluoroethylene (ETFE) etc may be suitable. A window may consist of a single pane or may have multiple adjoining panes. In this example, the window forms the base of the lid 17, although in other examples the window 30 could be embedded in the lid 17, hinged to the lid 17 or conduit 29, or separable from the lid 17. The window may be placed between the lid 17 and the conduit. The window may be latchable to the lid or to the conduit. The window may be provided with one or more seals to provide a substantially liquid-tight seal between the window and the conduit and/or between the window and the lid 17. With the lid 17 open, an operator can, for example, access the conduits 29 to clean the walls of the conduits or to clean the window 30 or to clear blockages from the slot where the liquid enters the conduits from the inlet 15. If a window is not fixed to the lid the bulbs 28 and reflectors 32 can also be directly accessed if desired. The conduits 29 and other parts of the flow path such as the slot that passes liquid into each conduit are located in the body of the module, not the lid. This means that the slot and conduit are not directly affected by the opening of the lid. In some situations, a user may allow flow to continue while the lid is open and the radiation for that module is turned off to inspect flow through the slot and/or conduit.
The windows 30 can enclose the UV bulbs 28 in a space in the lid 17 and help protect them from contamination. The UV bulbs are most efficient when operating within a specific temperature range which may be above ambient temperature. In order to regulate the temperature of the bulbs 28, airflow controllers may be provided to control a flow of air through the enclosed space. These may include passive airflow controllers such as vents or active airflow controllers such as fans. The ambient air may be relatively cool and may be used to cool the radiation sources. Generally cooling air may be provided, but in some cold climates, it may be desirable to warm the air. The air supply used for temperature regulation may be pre-cooled or pre-warmed by a heat pump. In other examples, one or more active cooling or heating elements (e.g. a Peltier element or heater wire) may be used to cool or warm the flow of air used for temperature regulation.
In some examples, the flow of liquid through any individual module can be inhibited (i.e. reduced or stopped by a controllable valve). For example, the flow through a module can be inhibited when the lid of that individual module is opened. Operation of the radiation source (e.g. UV bulbs) of any individual module can also be inhibited. For example, operation of the radiation source of a module can be inhibited when the lid of that module is opened. One or more sensors can be provided on the lid and/or on a module to sense opening of the lid and cause one or more flow and/or radiation controllers to inhibit the flow and/or radiation for that module.
The embodiment of
The flow of liquid through a module, e.g. one of the modules 14a-14h of
The provision of parallel modules allows one or more to be taken offline while others remain in use. For example, one module may need to be taken offline because a bulb has stopped working. Flow through this module can be stopped until the bulb has been replaced, while the other modules continue treating the liquid. In another example, the number of modules in use can be selected based on a desired throughput. Flow of liquid can be provided through a subset of the modules to achieve the desired throughput and the remaining module(s) taken offline. This may improve efficiency of the apparatus by only using the minimum number of modules necessary to meet a throughput requirement. One or more flow controllers, such as a valve block common to all modules or individual valves for each module, can be used to control flow through each module independently of flow through the others.
A radiation controller can also control the radiation source(s) of each module independently from the radiation source(s) of the other module(s). This can involve turning the radiation sources on and off or increasing or decreasing their output intensity. The radiation controller can be a switch or controller implementing a light control algorithm, for example. In one use, the radiation controller can turn off or decrease intensity of the radiation sources of any module that has low or no flow to save power. In another example, the radiation controller can control the intensity of the radiation as a continuous or stepped function of the flow rate.
It has been found that certain inlet designs/operation can cause splashing out into the flow channel at the time of flow start up for example due to liquid rushing into an inlet that has emptied of liquid and contains air. It was found that this splashing is avoidable by several techniques. These include ensuring the conduit that feeds liquid into the inlet is angled upwards prior to the inlet to prevent the liquid draining out when not in use; by the installation of a spring loaded check valve prior to the inlet that has a similar effect of preventing draining and passage of air back up the pipe; by the use of slow ramping up of the flowrate at the flow start up (for example via a variable speed pump control or by a slow opening valve) which allows air to slowly escape the inlet rather than being rapidly forced out.
It was found that deflectors positioned above the flow channel outside the exit of the inlet were also useful in reducing any splash emitting from that area. For example, these could be plates or brushes that intercept any ejected splash. However, it was found that the inlet is not the sole source of splashes and that in various cases splashes or liquid droplets can be emitted from the supercritical flow further down the flow channel, in some cases as far two thirds of the way down the channel or further.
While there is a limit to the height of these splash/ejections it can be desirable to have elements of the treatment apparatus located below this height to ensure an overall compact system design. While this may not be a problem for supercritical flows operated at lower flowrates and larger flow depths (thicknesses), as the flow depth decreases and/or as the flowrates increase it has been found that this issue becomes more problematic.
However, it has been discovered that ejection of liquid elements upwards out of a supercritical flow was totally or at least substantially eliminated for a liquid that passed through an inlet component having walls that define a passage with an entry section, an exit section with substantially constant height and width, and a transitional section between the entry and exit sections. The transitional section is wider than the entry section and deeper than the exit section, allowing the liquid to spread and thin out as it moves from the entry section to the exit section.
One exemplary inlet component is detailed with reference to
It has been found the flow rate that can be passed down the supercritical flow channel without incurring significant splashing is a function of flow depth where the larger the gap the higher the acceptable flowrate. It was also determined that this was not necessarily due to the increased ejection velocity that results from a smaller gap. Holding the flow depth constant, it was found that the amount of splashing or droplet ejection could be reduced to an acceptable or undetectable level using the inlet component for relatively high flow rates. An acceptable level of splashing or droplet ejection can depend on the application. It may be desirable to reduce splashing or droplet ejection to or below a very low level in applications with overhead components such as bulbs, reflectors or transmissive (e.g. quartz) windows. In trials, 33 test strips were arranged in alternating rows of two test strips and three test strips per row at a height of approximately 80 mm above a channel that was approximately 1500 mm long and 247 mm wide. The test strips were pieces of litmus paper approximately 9 mm wide with a length of approximately 68 mm. An acidic liquid was passed through the apparatus, with ejected liquid being detectable by the test strips. In these examples, a rate of ejection (that reached the test strips) of approximately 30 or fewer pinprick splashes on the test strips over a 6-hour or longer trial run was considered to be an acceptably low level of splashing or ejection.
For example, in one experimental setup an inlet component without an exit section was found to only be able to support a 90 litre per minute (l/m) flow rate with minor but acceptable splashing—a higher flow rate of 120 litre per minute (l/m) caused too much splashing and could cause unacceptable fouling of a treatment apparatus. This inlet component had a transition section with a length of about 160 mm and curved walls (similar to
An inlet component with the same about 160 mm transition section and 4 mm slot as above, but a shorter exit section of about 45 mm, was able to support flow rates of 120 l/m with minor but acceptable splashing but had an unacceptable result when operated at 160 l/m. An inlet component with an about 90 mm exit section and 4 mm slot but a shorter transition section of about 53 mm was able to support a flow rate of 120 l/m with no splashing and 150 l/m with minor but acceptable splashing but had an unacceptable result when operated at 190 l/m.
As is clear from the results above, a substantive lengthening of the exit section markedly reduces the amount of splashing or droplet ejection. Lengthening the transition section also has a substantial effect on reducing splashing and droplet ejection. Given this relationship, an inlet component can be designed to support a flow with an acceptable amount of splashing/droplet ejection, and maintain the splashing/droplet ejection at an acceptable level for higher flow rates than prior systems could, by adjusting the length of one or both of the exit section and transition section. In some examples, a length of about 45 mm or more was found to be suitable for the exit section, particularly at lower flow rates (e.g. 120 l/m for a 4 mm slot and a 250 mm wide flow channel), and about 90 mm was found to provide good results at a wide range of flow rates (e.g. 230 l/m for a 4 mm slot and a 250 mm wide flow channel). In some examples, a length of about 53 mm or more was found to be suitable for the transitional section, particularly at lower flow rates (e.g. 150 l/m for a 4 mm slot and a 250 mm wide flow channel), and a length of about 160 mm or more was found to provide good results at a wide range of flow rates (e.g. including 230 l/m for a 4 mm slot and 250 mm wide flow channel). The exemplary inlet component 70′ of
It has also been found that the inlet component can improve the shape of the downstream flow through the channel by reducing differences in depth across the width of the flow. Ridges, similar to bow waves of a boat, can form in the supercritical flow channel. These lead to areas of increased flow thickness and may result in inadequate or uneven treatment of the liquid. It was found that increasing the length of the exit section reduced these ridges. For example the inlet component 70′ of
The inlet component 50 of
The inlet component might be manufactured from plate material or from a block of material. The material could be metal such as stainless steel or aluminium or it could be plastic. In some examples the inlet component 50 can be fully or partially made from sheets/plates of material and/or tubing that are joined together, for example by screws or welding. It was however discovered that it is important that any thin material used adjacent to the flow is stiff enough or the flow can cause it to resonate and negatively impact the flow downstream from the inlet. The inlet component could include a base at the bottom of the liquid passage through the component. In another example it could be fully or partially cast for example from stainless steel or aluminium or a resin. In another example, the inlet component could be fully or partially milled from a block of material.
The inlet component could be open at the bottom (e.g. without a base along at least part of its length) so that when the block is fixed in position into a conduit the base of the conduit forms at least part of the base of the inlet component at the bottom of the liquid passage through the inlet component. In one example of an inlet component that is open at the bottom, the inlet component is milled from a block of plastic without a base in the sections 56 and 54 (that define the transition and exit sections as detailed further below). In this example, the inlet component can be formed without a base in the section 52 (that defines the entry section as detailed further below) or the section 52 could be provided by an element with a circular passage such as a bore through the block or a pipe. Other methods of inlet component manufacture are also possible including having other walls that open but which are then enclosed when in use. Having an open base or any other opening wall may offer benefits in terms of lowered manufacturing cost or may be useful if access for cleaning or other servicing for example removal of any blockage is required.
The inlet component is configured such that the liquid passage has three sections: an entry section (through section 52 of the liquid component); an exit section (through section 54 of the inlet component); and a transitional section (through section 56 of the inlet component) between the entry section and the exit section. The width dimension is indicated by the arrow 62. The height dimension is indicated by the arrow 60. Although the arrows 60 and 62 are shown at particular places along the length of the inlet component 50 in
The width 62 can increase non-linearly along the transitional section. For example, the wall(s) that define the passage can curve smoothly between the entry section and exit section so that the width smoothly increases between the entry section and exit section. The width can initially increase superlinearly from the entry section towards a central portion of the transitional section then increase sublinearly from the central portion to the exit portion. In other words, the sides of the passage (e.g. as defined by side walls 64) can initially curve outwards from the entry section then curve inwards towards the exit section. In other words, the second derivative of width with respect to length along the passage is positive between the entry section and the central portion of the transitional section and is negative between the central portion of the transitional section and the exit section. Note that the central portion need not be halfway along the transitional section and it may be at various places between the two ends of the transitional section.
It is the configuration of the inner surfaces of the walls that is important for defining the shape and sections of the passage. The exterior shape of the inlet component 50 could vary without affecting the configuration of the liquid passage and without affecting the flow properties of liquid passing through the inlet component.
Flow controlling elements may be incorporated within the inlet component for example these could include flow baffles, flow vanes, groves or conduits that act to direct the flow from the entry section to or into the exit section.
The inlet components 70, 70′ and 70″ correspond to the designs tested in the trials discussed above. Other designs, such as the inlet components 70″ and 70″, are possible and may achieve similar advantageous results.
The inlet component 70 of
The inlet component 70′ of
The inlet component 70″ of
In the inlet components described previously, the entry section can be arranged at various angles to introduce liquid flow at different angles, not just horizontally as shown in the figures. For example, it could enter from the top or bottom of the inlet component. In these arrangements, the inlet dimensions referred to as height and width are to be understood to refer to two perpendicular dimensions that are transverse to the liquid flow.
Although all of the inlet components 70, 70′. 70″, 70′″, 70″ are designed to decrease splashing and droplet ejection, some may be better suited to certain applications than others. For example, material such as particulates or slime may build up in the corners of the squarer transition sections 76″, 76′″ of the inlet components 70″, 70″. This may make them more suitable for use with liquid that is relatively free of such materials or organics compounds materials that may cause bacterial slime to grow, whereas the inlet components 70, 70′, 70″ may be better choices for treating liquid with such material, for example effluent. On the other hand, the inlet components 70″, 70″ may be easier and more cost effective to manufacture than inlet components 70, 70′, 70″, making them potentially more suitable to applications where cost effectiveness is important. Regarding splashing and droplet ejection, testing to date has shown inlet components 70 and 70′ to be the most effective, with inlet component 70′ being slightly more effective than inlet component 70.
Alternative forms of inlet component 80, 80′, 80″ are shown in
The second section can gradually change height as shown in
The lengths of sections of the inlet components 80, 80′, 80″ can be selected to reduce splashing and liquid ejection in the same manner as the inlet components previously discussed. The lengths of the first sections 86, 86′, 86″ of the inlet components 80, 80′, 80″ can be the same as the exit sections of the inlet components previously discussed. The lengths of the second sections 84, 84′, 84″ of the inlet components 80, 80′, 80″ can be the same as the transitional sections of the inlet components previously discussed.
The inlet components can be expected to work in a similar manner at different scales provided they are scaled with geometric and dynamic similarity.
While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.
| Number | Date | Country | Kind |
|---|---|---|---|
| 777519 | Jun 2021 | NZ | national |
| 2021221445 | Aug 2021 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NZ2022/050082 | 6/23/2022 | WO |
