Abstract
An aerosol-generating device is provided, including: a membrane having an aerosol-generation zone, in which the aerosol-generation zone includes a plurality of nozzles, the plurality of nozzles being the only nozzles in the aerosol-generation zone; and an actuator coupled to the membrane, in which the actuator is configured to excite the membrane to induce a vibration of the membrane at one or more predetermined modal frequencies of the membrane such that a liquid aerosol-forming substrate passing through the plurality of nozzles is aerosolised, in which more than 50% of the plurality of nozzles are located closer to antinodes than to nodes of the membrane, where the antinodes and the nodes correspond to the membrane being excited at the one or more predetermined modal frequencies of the membrane, and in which the membrane progressively changes in thickness from a centre of the membrane to a peripheral edge of the membrane.
Claims
1.-15. (canceled)
16. An aerosol-generating device, comprising: a membrane having an aerosol-generation zone, in which the aerosol-generation zone comprises a plurality of nozzles, the plurality of nozzles being the only nozzles in the aerosol-generation zone; and an actuator coupled to the membrane, wherein the actuator is configured to excite the membrane to induce a vibration of the membrane at one or more predetermined modal frequencies of the membrane such that a liquid aerosol-forming substrate passing through the plurality of nozzles is aerosolised, wherein more than 50% of the plurality of nozzles are located closer to antinodes than to nodes of the membrane, where the antinodes and the nodes correspond to the membrane being excited at the one or more predetermined modal frequencies of the membrane, and wherein the membrane progressively changes in thickness from a centre of the membrane to a peripheral edge of the membrane.
17. The aerosol-generating device according to claim 16, wherein the plurality of nozzles are non-homogenously distributed over the aerosol-generation zone.
18. The aerosol-generating device according to claim 16, wherein at least 60% of the plurality of nozzles are located within a region extending either side of the antinodes, the region being where a magnitude of displacement of the membrane is at least 60% of a magnitude of displacement of the membrane at the antinodes for the corresponding one or more predetermined modal frequencies.
19. The aerosol-generating device according to claim 18, wherein all of the plurality of nozzles are located within the region extending either side of the antinodes.
20. The aerosol-generating device according to claim 16, wherein the one or more predetermined modal frequencies comprise a first predetermined modal frequency of the membrane and a second predetermined modal frequency of the membrane, and wherein the plurality of nozzles are preferentially located in a first and a second intersection region of the aerosol-generation zone, in which: for the first intersection region, antinodes corresponding to the first predetermined modal frequency of the membrane are proximate to nodes corresponding to the second predetermined modal frequency of the membrane, and for the second intersection region, antinodes corresponding to the second predetermined modal frequency of the membrane are proximate to nodes corresponding to the first predetermined modal frequency of the membrane.
21. The aerosol-generating device according to claim 20, wherein all of the plurality of nozzles are located in the first and the second intersection regions.
22. The aerosol-generating device according to claim 20, wherein: for the first intersection region, the nodes corresponding to the second predetermined modal frequency are located within a first zone extending either side of the antinodes corresponding to the first predetermined modal frequency, the first zone being where a magnitude of displacement of the membrane is at least 60% of a magnitude of displacement of the membrane at the antinodes for the first predetermined modal frequency, and for the second intersection region, the nodes corresponding to the first predetermined modal frequency are located within a second zone extending either side of the antinodes corresponding to the second predetermined modal frequency, the second zone being where the magnitude of displacement of the membrane is at least 60% of the magnitude of displacement of the membrane at the antinodes for the second predetermined modal frequency.
23. The aerosol-generating device according to claim 16, wherein the aerosol-generating device is configured to selectively apply and release a constraint to the membrane so as to adjust a response of the membrane to the one or more predetermined modal frequencies.
24. The aerosol-generating device according to claim 23, wherein the aerosol-generating device is configured to selectively apply and release the constraint along one or more portions of the periphery of the membrane.
25. The aerosol-generating device according to claim 16, wherein the actuator is further configured to selectively excite different parts of the membrane.
26. The aerosol-generating device according to claim 25, wherein the actuator comprises a plurality of actuator segments, each actuator segment coupled to a different part of the membrane.
27. The aerosol-generating device according to claim 16, wherein the actuator is further configured to apply a modulated driving signal to the membrane in order to excite the membrane.
28. The aerosol-generating device according to claim 16, wherein the membrane progressively reduces in thickness from a centre of the membrane to a peripheral edge of the membrane.
29. The aerosol-generating device according to claim 16, wherein the membrane progressively increases in thickness from a centre of the membrane to a peripheral edge of the membrane.
30. An aerosol-delivery system, comprising: the aerosol-generating device according to claim 16; and a liquid feed configured to supply a liquid aerosol-forming substrate to the membrane.
Description
[0102] FIG. 1 shows a schematic view of an aerosol-delivery system, the aerosol-delivery system being in the form of a smoking article for generating an inhalable aerosol.
[0103] FIG. 2 shows a perspective view of an aerosol-generating device in accordance with an embodiment.
[0104] FIG. 3 shows a plan view of a membrane of the aerosol-generating device of FIG. 2.
[0105] FIG. 4 shows a graph of displacement versus radial distance for a circular membrane clamped about the periphery of the membrane, in response to vibration mode (0,3) being activated in the membrane. The graph also includes an indication of the locations of nozzles in the membrane.
[0106] FIG. 5a shows a plan view of a circular membrane clamped about the periphery of the membrane and overlaid with contour lines indicating the displacement of different parts of the membrane in response to vibration mode (0,2) being activated in the membrane.
[0107] FIG. 5b shows a plan view of a circular membrane clamped about the periphery of the membrane and overlaid with contour lines indicating the displacement of different parts of the membrane in response to vibration mode (1, 2) being activated in the membrane.
[0108] FIG. 5c shows a plan view of a circular membrane clamped about the periphery of the membrane and overlaid with contour lines indicating the displacement of different parts of the membrane in response to vibration mode (3,1) being activated in the membrane.
[0109] FIG. 6a shows a plan view of a square membrane simply supported about the periphery of the membrane and overlaid with contour lines indicating the displacement of different parts of the membrane in response to vibration mode (1, 2) being activated in the membrane.
[0110] FIG. 6b shows a plan view of a square membrane simply supported about the periphery of the membrane and overlaid with contour lines indicating the displacement of different parts of the membrane in response to vibration mode (3, 3) being activated in the membrane.
[0111] FIG. 7 shows a graph of displacement versus radial distance for a circular membrane clamped about the periphery of the membrane, in response to two separate vibration modes (0,3), and (4,1), being activated in the membrane. The graph also includes an indication of the locations of nozzles in the membrane.
[0112] FIGS. 8a and 8b show a side elevation view of an embodiment of the aerosol-generating device configured to selectively apply and release a constraint to the membrane. FIG. 8a shows the constraint applied to the membrane, whereas FIG. 8b shows the constraint released from the membrane.
[0113] FIG. 9 shows a side elevation view of an embodiment of the aerosol-generating device in which the membrane progressively reduces in thickness when traversing from a central region of the membrane towards the periphery of the membrane.
[0114] FIG. 10 shows a side elevation view of an embodiment of the aerosol-generating device in which the membrane progressively increases in thickness when traversing from the central region of the membrane towards the periphery of the membrane.
[0115] FIG. 11 shows a perspective view of a first embodiment of a liquid feed assembly.
[0116] FIG. 12 shows a perspective view of a second embodiment of a liquid feed assembly.
[0117] FIG. 13 shows a perspective view of a third embodiment of a liquid feed assembly.
[0118] FIG. 1 is a schematic view of an aerosol-delivery system 100. For the embodiment shown in FIG. 1, the aerosol-delivery system 100 is a smoking system for generating an inhalable aerosol 101. The system 100 has an elongate housing 102. The elongate housing 102 contains a power source 103, electronic control circuitry 104, a cartridge 105, a liquid feed assembly 106 and an aerosol-generating device 107. The power source 103 is coupled to the electronic control circuitry 104 and the aerosol-generating device 107 to provide power thereto. The electronic control circuitry 104 is configured to control operation of the aerosol-generating device 107. In an alternative embodiment in which the power source 103 is a rechargeable battery, the electronic control circuitry 104 is also configured to control charging of the rechargeable battery. The elongate housing 102 has a distal end 108 and a mouth end 109. A mouthpiece 110 is provided at the mouth end 109 of the housing 102. The cartridge 105 contains a reservoir of a liquid-forming substrate (not shown). Although not shown in FIG. 1, the cartridge 105 is replaceable, with the elongate housing 102 adapted to enable the cartridge to be removed and replaced. Embodiments of exemplary aerosol-generating devices 107 suitable for use with the aerosol-delivery system 100 illustrated in FIG. 1 are described in the subsequent paragraphs.
[0119] FIG. 2 illustrates an embodiment of an aerosol-generating device 107. The device 107 has a membrane 20 and an actuator 40 coupled to the membrane. For the embodiment shown in FIG. 2, the membrane 20 has a circular shape when viewed in plan. The actuator 40 is segmented about its periphery, having four discrete segments 41, 42, 43, 44. Each segment 41, 42, 43, 44 has an upper half and a lower half acting on respective upper and lower surfaces of corresponding segments of the membrane 20. Each actuator segment 41, 42, 43, 44 thereby acts to constrain the corresponding segment of the membrane 20. Each actuator segment 41, 42, 43, 44 is designed so as to be driven independently of the other segments. During operation of the actuator 40, the segments 41, 42, 43, 44 may be driven so that they are in phase with each other, or in any desired phase relationship. In an alternative embodiment not shown in the figures, the actuator 40 may be continuous and non-segmented.
[0120] FIG. 3 shows a plan view of the membrane 20 of the aerosol-generating device 107, i.e. when viewed in the direction of arrow A of FIG. 2. The membrane 20 is circular when viewed in plan. For convenience, the actuator 40 is excluded from FIG. 3. The membrane 20 has an aerosol-generation zone 21 (the periphery of which is represented by a dashed line in FIG. 3). The aerosol generation zone 21 is provided with a plurality of nozzles 22. The nozzles 22 are in the form of holes which extend through the thickness of the membrane 20. For the embodiment shown in FIG. 3, the plurality of nozzles 22 are exclusively located in two annular regions 23, 24. An annular gap 25 is present between the periphery 26 of the membrane 20 and the periphery of the aerosol generation zone 21. The annular gap 25 provides space to enable the segments of the actuator 40 (see for example, FIG. 2) to be coupled to the membrane 20.
[0121] The actuator 40 is configured to excite the membrane 20 to induce a vibration of the membrane at one or more predetermined modal frequencies of the membrane. In various embodiments, the actuator 40 may be configured to be excite the membrane 20 to induce a vibration of the membrane at multiple discrete modal frequencies of the membrane. However, for ease of understanding, the displacement of the membrane 20 in response to the actuator 40 exciting a single vibration mode of the membrane will initially be discussed, with the discussion referring to FIG. 4. Each vibration mode of the membrane 20 will have a corresponding modal frequency.
[0122] FIG. 4 shows a graph of displacement of the circular membrane 20 versus radial distance, r, from the centre 27 of the membrane 20 (see FIG. 3) for vibration mode (0, 3) of the membrane, with the entire periphery 26 of the membrane clamped by the actuator 40. The radial distance, r, in FIG. 4 is expressed as a fraction of the radius, R, of the aerosol generation zone 21. For mode (0, 3), the number 0 indicates that no circumferential vibration mode is activated in the membrane 20, whereas the number 3 indicates that the third harmonic vibration mode in the radial direction (relative to the centre 27 of the membrane) is activated.
[0123] As illustrated in FIG. 4, when mode (0,3) is activated in the membrane 20, antinodes are present at three regions of the membrane. The displacement shown in FIG. 4 is annular about the centre 27 of the membrane 20 for mode (0,3), having three defined antinode regions 201, 202, 203 corresponding to the locations of the antinodes. The antinode displacement magnitude is a maximum at the centre 27 of the membrane 20 (i.e. in antinode region 201), and progressively reduces with increasing radial distance from the centre towards the periphery 26 of the membrane (i.e. see antinode regions 202, 203). The reduction in magnitude of the displacement at the antinodes with increasing radial distance, r, is due to the periphery 26 of the membrane 20 being clamped by the actuator 40 (see FIG. 2). FIG. 4 includes grey bands showing the width of the annular regions 23, 24 in which the plurality of nozzles 22 are provided. The annular regions 23, 24 are localised about (i.e. proximate to) the corresponding antinodes (see antinode regions 202, 203 in FIG. 4). The wavelength, λ, of a waveform associated with this vibration mode (0,3) is indicated on FIG. 4.
[0124] When a liquid aerosol-forming substrate is supplied to the membrane 20 while the actuator 40 activates mode (0,3) of the membrane, aerosol droplets will be generated by the nozzles 22 located in the annular regions 23, 24. As these annular regions 23, 24, and thereby the plurality of nozzles 22, are localised about the antinodes (i.e. antinode regions 202, 203) for vibration mode (0,3), the energy and velocity imparted to the aerosol droplets by the membrane 20 will be maximised. Such an arrangement of nozzles 22 localised about the antinodes 202, 203 will also enhance the Weber number and the distance which the membrane 20 is able to eject aerosol droplets from the membrane. If the actuator 40 was instead, or additionally, configured to excite a different vibration mode in the membrane, then the plurality of nozzles 22 would be preferentially located proximate to the antinodes corresponding to that different vibration mode.
[0125] FIGS. 5a-c and FIGS. 6a-b illustrate the displacement response of different membrane geometries to different vibration modes.
[0126] FIGS. 5a to 5c show plan views of a circular membrane 20 clamped about the periphery 26 of the membrane for different vibration modes. Each vibration mode will have its own corresponding modal frequency. Graduated contours are overlaid on the membrane 20 for each of FIGS. 5a to 5c, illustrating the displacement response of different parts of the membrane to the particular vibration mode.
[0127] FIG. 5a shows the displacement of the clamped circular membrane 20 for vibration mode (0,2). For mode (0, 2), the number 0 indicates that no circumferential vibration mode is activated in the membrane 20, whereas the number 2 indicates that the second harmonic vibration mode in the radial direction (relative to the centre 27 of the membrane) is activated. The displacement response of the membrane 20 for this vibration mode has two defined antinode regions along a line extending radially out from the centre 27 of the membrane.
[0128] FIG. 5b shows the displacement of the clamped circular membrane 20 for vibration mode (1,2). For mode (1,2), the number 1 indicates that the fundamental circumferential vibration mode is activated in the membrane 20, whereas the number 2 indicates that the second harmonic vibration mode in the radial direction (relative to the centre 27 of the membrane) is activated. The displacement response of the membrane 20 for this vibration mode has a single antinode region in a circumferential direction for each half of the membrane, as well as two antinode regions along a line extending radially out from the centre 27 of the membrane.
[0129] FIG. 5c shows the displacement response of the clamped circular membrane 20 for vibration mode (3,1). For mode (3, 1), the number 3 indicates that the third harmonic circumferential vibration mode is activated in the membrane 20, whereas the number 1 indicates that the fundamental vibration mode in the radial direction (relative to the centre 27 of the membrane is activated. The displacement response of the membrane 11 for this vibration mode has three antinode regions in a circumferential direction for each half of the membrane, as well as one antinode region along a line extending radially out from the centre 27 of the membrane.
[0130] FIGS. 6a and 6b show plan views of a square membrane 20′ simply supported about the periphery 26′ of the membrane for different vibration modes. Each vibration mode will have its own corresponding modal frequency. Graduated contours are overlaid on the membrane 20′ for each of FIGS. 6a and 6b, illustrating the displacement response of different parts of the membrane to the particular vibration mode.
[0131] FIG. 6a shows the displacement of the simply supported square membrane 20′ for vibration mode (1,2). For mode (1, 2), the number 1 indicates that the fundamental vibration mode in the y-direction is activated in the membrane 20′, whereas the number 2 indicates that the second harmonic vibration mode in the x-direction is activated. The displacement response of the membrane 20′ for this vibration mode has a single antinode region in the y-direction, as well as two antinode regions in the x-direction.
[0132] FIG. 6b shows the displacement of the simply supported rectangular membrane 20′ for vibration mode (3,3). For mode (3,3), the number 3 indicates that the second harmonic vibration mode in both the x and y-directions is activated in the membrane 20′. The displacement response of the membrane 20′ for this vibration mode has three antinode regions in each of the x and y-directions.
[0133] If the actuator 40 was to be configured to excite any of the vibration modes shown for the circular clamped membrane 20 of FIGS. 5a to 5c or the square simply-supported membrane 20′ of FIGS. 6a and 6b, the displacement response contour plots provide an indication of where the peak displacement magnitude (i.e. crest or trough) is likely to occur in the membrane. Such plots can assist in preferentially locating the plurality of nozzles 22 in the membrane 20 such that they are proximate to those regions of the membrane experiencing highest displacement magnitudes (i.e. the antinodes). As previously stated, such preferential locating of the nozzles in the vicinity of the antinodes assists in maximising the energy and velocity imparted to aerosol droplets during use of the aerosol-generating device 107.
[0134] In an alternative embodiment of the aerosol-generating device, the actuator 40 is configured to excite the membrane 20 of the aerosol-generating device 107 at two discrete predetermined modal frequencies. Each discrete modal frequency is associated with a corresponding vibration mode. By way of illustration, FIG. 7 illustrates the vibration response of a clamped circular membrane 20 with increasing radial distance, r, from the centre 27 of the membrane for two different vibration modes of the membrane. The two vibration modes are modes (0,3) and (4,1) —represented by the solid and dashed lines respectively of FIG. 7. For mode (0,3), the number 0 indicates that no circumferential vibration mode is activated in the membrane 20, whereas the number 3 indicates that the third harmonic vibration mode in the radial direction (relative to the centre 27 of the membrane) is activated. For mode (4,1), the number 4 indicates that the fourth harmonic circumferential vibration mode is activated in the membrane 20, whereas the number 1 indicates that the fundamental vibration mode in the radial direction (relative to the centre 27 of the membrane) is activated. For this alternative embodiment, the plurality of nozzles 22 are located in two discrete regions 231, 241 of the aerosol-generation zone 21. The first of these regions 231 defines a circle located at the centre of the membrane 20, whereas the second of these regions 241 is in the form of an annular band. The first region 231 is a first intersection region, in which antinodes corresponding to the vibration mode (0,3) are located proximate to nodes corresponding to the vibration mode (4,1). The second region 241 is a second intersection region, in which antinodes corresponding to the vibration mode (4,1) are located proximate to nodes corresponding to the vibration mode (0,3). When the actuator 40 excites mode (0,3) and liquid aerosol-forming substrate is fed to the membrane 20, aerosol droplets are ejected predominantly from the nozzles 22 of the first intersection region 231. However, once the actuator 40 switches to exciting mode (4,1), aerosol droplets instead emanate predominantly from the nozzles 22 of the second intersection region 241.
[0135] FIGS. 8a and 8b show a schematic view of an embodiment in which the aerosol-generating device 107 is configured to selectively apply and release a constraint to the membrane 20. For convenience, the location of the plurality of nozzles 22 in the membrane 20 for this embodiment are not shown in FIG. 8a or 8b. As shown in FIG. 8a, both two opposing edges of the membrane 20 are clamped. A clamp 41 is provide on the left-hand edge of the membrane 20. The clamp 41 is fixed, by which is meant that the clamp 41 continues to clamp the left-hand edge of the membrane 20 during operation of the actuator 40 of the aerosol-generating device 107. A releasable clamp 42 is provided on the right-hand edge of the membrane 20. The releasable clamp 42 is coupled to an electromechanical switch 43. As shown in FIGS. 8a and 8b (see arrow B), the electromechanical switch 43 is operable to move an upper half 42a of the releasable clamp 42 relative to a lower half 42b of the clamp, to selectively apply and release the upper half 42a from the membrane 20 and thereby apply and release the clamping of the right-hand edge of the membrane. Releasing and re-applying the clamping to an edge of the membrane 20 when the membrane is excited by the actuator 40 at a given predetermined modal frequency of the membrane has the effect of changing the displacement response of the membrane for that modal frequency. The change in displacement response of the membrane 20 in response to the change in constraint applied to the membrane can be exploited, by having the plurality of nozzles 22 preferentially located proximate to antinodes corresponding to the displacement of the membrane 20 for each of the differing constraint states of the membrane. FIGS. 9 and 10 illustrate two different embodiments of the aerosol-generating device 107, in which there is a progressive change in the thickness of the membrane 20 when traversing from a central region of the membrane towards the periphery of the membrane. The nozzles 22 are represented schematically in both FIGS. 9 and 10, with the actuator 40 coupled to the upper and lower surfaces of the membrane in the region of the membrane's periphery. FIG. 9 shows an example in which the membrane 20 progressively reduces in thickness when moving from the centre of the membrane towards the periphery of the membrane. FIG. 10 shows the converse situation in which the membrane 20 progressively increases in thickness when moving from the centre of the membrane towards the periphery of the membrane. The thickness of the membrane 20 is shown at a radial location r, relative to the centre of the membrane, with the thickness represented by symbol tr.
[0136] Liquid aerosol-forming substrate may be fed to the membrane 20 of the aerosol-generating device 107 in various ways. FIGS. 11, 12 and 13 illustrate examples of a liquid feed assembly 106, 106′, 106″ for supplying one or more liquid aerosol-forming substrates to a membrane 20 of an aerosol-generating device 107. For convenience, the actuator 40 is not shown in any of FIGS. 11 to 13.
[0137] FIG. 11 illustrates a liquid feed assembly 106 operable to supply a liquid aerosol-forming substrate to the membrane 20. The liquid feed assembly 106 has a moveable stage 1061. Flexible tubing 1062 extends between a reservoir of liquid aerosol-forming substrate (not shown) and a feed nozzle 1063. Arrow L shows the passage of liquid aerosol-forming substrate from the reservoir through the flexible tubing 1062. Although not shown in FIG. 11, an electric motor is coupled to the movable stage 1061. Operation of the motor causes the movable stage 1061 to traverse along the aerosol-generation zone 21 of the membrane 20 along a path P. During excitation of the membrane 20 by the actuator 40, the moveable stage 1061 traverses over the membrane to supply liquid aerosol-forming substrate through the feed nozzle 1063 proximate to antinodes and nozzles 22 corresponding to the predetermined modal frequency. The liquid feed assembly 106 shown in FIG. 11 may be applied to any shape of membrane 20.
[0138] FIG. 12 illustrates an alternative liquid feed assembly 106′. The liquid feed assembly 106′ is shown in conjunction with a circular membrane 20. The liquid feed assembly 106′ has three concentrically arranged tubes 1064, 1065, 1066. The radially-innermost tube 1064 defines a first concentric liquid aerosol-forming substrate feed channel for feeding a first liquid aerosol-forming substrate to the membrane 20. An annular gap between the radially-innermost tube 1064 and the middle tube 1065 defines a second concentric liquid aerosol-forming substrate feed channel for feeding a second liquid aerosol-forming substrate to the membrane 20. An annular gap between the middle tube 1065 and the radially-outermost tube 1066 defines a third concentric liquid aerosol-forming substrate feed channel for feeding a third liquid aerosol-forming substrate to the membrane 20. Each of the concentrically-arranged feed channels are fed or filled with a respective liquid aerosol-forming substrate from a reservoir (not shown). The concentrically-arranged first, second and third liquid aerosol-forming substrate feed channels supply their respective liquid aerosol-forming substrates to corresponding annular regions of the membrane 20. In an alternative embodiment (not shown), a wicking material may be located in each of the concentrically-arranged first, second and third liquid aerosol-forming substrate feed channels, with the wicking material for each concentric feed channel wetted with a respective liquid aerosol-forming substrate for that channel. In a further alternative embodiment, the liquid feed assembly 106′ may also be used in conjunction with an elliptical membrane.
[0139] FIG. 13 illustrates a further alternative liquid feed assembly 106″. The liquid feed assembly 106″ is shown in conjunction with a square membrane 20′. The liquid feed assembly 106″ has three linear channels 1067, 1068, 1069 defined in a substrate 1070. Each of the linear channels 1067, 1068, 1069 is fed with a respective liquid aerosol-forming substrate from a reservoir (not shown) by means of a respective liquid aerosol-forming substrate inlet 1071, 1072, 1073. The linear channels 1067, 1068, 1069 feed their respective liquid aerosol-forming substrates to corresponding linear regions of the membrane 20′. In an alternative embodiment (not shown), a wicking material is located in each of the linear channels 1067, 1068, 1069, with the wicking material for each channel wetted with a respective liquid aerosol-forming substrate for that channel.
[0140] Although not shown in FIGS. 11-13, the liquid feed assemblies 106, 106′, 106″ include one or more micropumps to actively feed the liquid aerosol-forming substrates to the membrane 20, 20′. The micropump(s) of the liquid feed assemblies 106, 106′, 106″ would be coupled to and powered by a power source (for example, the power source 103 shown in FIG. 1—see dashed line connecting to liquid feed assembly 106 in FIG. 1).
[0141] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number “A” is understood as “A”±10% of “A”. Within this context, a number “A” may be considered to include numerical values that are within general standard error for the measurement of the property that the number “A” modifies. The number “A”, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which “A” deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.
