the present invention will now be described more fully hereinafter , in which preferred embodiments of the invention are shown . this invention may , however , be embodied in different forms and should not be construed as limited to the embodiments set forth herein . rather , these embodiments are provided so that this disclosure will be thorough and complete , and will fully convey the scope of the invention to those skilled in the art . in the drawings , like numbers refer to like elements throughout . thicknesses and dimensions of some components may be exaggerated for clarity . referring now to the drawings , a singulating device , illustrated broadly at 10 , is illustrated in fig1 and 2 . the device 10 includes a bulk article housing 11 in which a plurality of small articles a are suspended in fluidized motion . the housing 11 includes a surrounding wall 12 , a floor 13 , and a ceiling 14 . the wall 12 may be continuous or segmented ( i . e ., it may comprise multiple contiguous walls ), may have a door 12 a filling for access for articles a and is preferably transparent to allow visual access to the articles a contained therein . similarly , the floor 13 and ceiling 14 may smoothly merge with the wall 12 or may form distinct corners therewith . those skilled in this art will recognize that housings of many shapes and configurations may be suitable for use with the present invention . in the illustrated embodiment , the floor 13 includes a screen 15 or other foraminous member that allows air passage into the housing 11 but not passage of the articles a out . similarly , the ceiling 14 includes a screen 16 or other foraminous member that functions to keep articles a in , but allow air passage ; in this instance the air flows out of the housing 11 . a blower 17 or other device for inducing airflow is attached to a low pressure plenum 17 a mounted above the screen 16 . the blower 17 is included to create a negative pressure differential with respect to ambient air pressure by drawing air from outside the housing through the screen 15 , into the cavity of the housing 11 , and out through the screen 16 . the illustrated embodiment also includes a jet nozzle 18 or other jet aperture located on the wall 12 . the jet nozzle 18 is oriented to direct a jet into the housing 11 toward an exit channel 20 located opposite the housing from the jet nozzle 18 . access to the nozzle 18 is controlled by a valve 18 a , which is fluidly attached to a positive pressure source 28 ( described in detail below ). referring still to fig1 and 2 , at the lower portion of the wall 12 , the exit channel 20 extends away from the housing 11 opposite the jet nozzle 18 . an article - orienting unit 30 is located at the mouth of the exit channel 20 to singulate articles a entering the exit channel 20 . these components are described in detail hereinbelow . referring now to fig3 a - 3c , the exit channel 20 includes a primary lumen 21 that extends downstream from the article - orienting unit 30 to terminate at an outlet 22 . the lumen 21 defines a downstream flow path p therein . as used herein , the term “ downstream ” means the direction that articles a travel in moving from the housing 11 to the outlet 22 . conversely , the term “ upstream ” means the direction opposite the downstream direction . it should be noted that , relative to an absolute x - y - z coordinate axis system , these directions may shift as articles a move in the exit channel 20 ( for example , in the illustrated embodiment , the articles a move directly away from the housing 11 , then turn downwardly ). the “ longitudinal ” dimension of a structure or component is intended to be parallel with the downstream direction , and the “ transverse ” dimension of a structure or component is intended to be normal to the downstream direction . in the illustrated embodiment , the lumen 21 has a cross - section that permits the passage of only one article at a time ; i . e ., two or more articles may not travel in the lumen 21 side - by - side . preferably , the lumen has a cross - section that generally resembles , but is somewhat larger than , that of the transverse cross - section of an article a traveling in the lumen 21 . for example , the lumen 21 of the channel 20 can be sized to be generally rectangular in cross section , with a height or width dimension slightly smaller than two minimum dimensions α of the articles a ( see fig4 a and 4c ) to prevent the simultaneous passage of two articles a . a forward jet pressure chamber 24 and a rear pressure jet chamber 25 are mounted to the exit channel 20 . the forward jet pressure chamber 24 is in fluid communication with the lumen 21 via a pair of forward jet apertures 26 a , 26 b , each of which is oriented at an angle ( preferably between about 1 and 89 degrees , and more preferably between 5 and 50 degrees ) relative to the longitudinal axis of the lumen 21 such that a jet exiting the forward jet apertures 26 a , 26 b enhances flow in the lumen 21 toward the outlet 22 . the rear pressure jet chamber 25 is in fluid communication with the lumen 21 via a rear jet aperture 27 , which is oriented at an angle ( preferably between about 1 and 89 degrees , and more preferably between 5 and 50 degrees ) relative to the longitudinal axis of the lumen 21 such that a jet exiting the rear jet aperture 27 impedes flow in lumen 21 toward the outlet 22 . in some embodiments , any or all of the forwardly and rearwardly - directed apertures may be arranged in combinations of any number . a common pressure source 28 is attached to each of the forward and rear pressure jet chambers 24 , 25 and , as noted above , the jet nozzle 18 . the pressure is each chamber 24 , 25 , 18 is regulated by a respective valve 29 a , 29 b , 18 a . those skilled in this art will recognize that the pressure in each chamber 24 , 25 , 18 , or in fact each jet aperture 26 a , 26 b , 27 , 18 , may be controlled by a separate pressure source . thus , it is to be understood that when separate “ first ”, “ second ”, “ third ” or even “ fourth ” pressure sources are described , these pressure sources may be common ( i . e ., coincident ) sources , or any or all of these may be separate sources . an article sensor 23 is positioned near the outlet 22 and is configured to count passing articles a as they travel through the lumen 21 . exemplary sensors include an opposing led / photo - transistor pair and reflective , capacitive , or mechanical switches . a controller 40 is operatively connected with the valves 29 a , 29 b , 18 a and with the sensor 23 . the controller 40 causes the valves 29 a , 29 b , 18 a to open or close depending on the number of articles a that have been counted by the sensor 23 at any particular point in time . the controller 40 can be any number of controller units known to those skilled in this art as being suitable for receiving signals from the sensor 23 and transmitting operating signals to the valves 29 a , 29 b , 18 a ; an exemplary controller is the 87518 - bit micro controller , available from intel . it should be recognized that the controller 40 may be connected directly to the pressure source 28 ( or any other pressure sources in embodiments in which multiple pressure sources are employed ) to activate them directly rather than operating the valves . referring now to fig5 a - 5c , the article - orienting unit 30 has a pair of generally parallel , spaced panels 31 a , 31 b and a third panel 32 that is generally perpendicular to the panels 31 a , 31 b . the downstream ends of these panels 31 a , 31 b , 32 abut the mouth of the exit channel 20 and their upstream ends extend slightly upstream into the housing 11 . one skilled in the art will recognize that the downstream ends of one or all of the aforementioned panels may extend most or all the entire length of the lumen 21 , ensuring that only one article a at a time may pass therein . the panels 31 a , 31 b are spaced apart a distance a , and the panel 32 is spaced from an upstream portion 20 a of the exit channel 20 a distance b , thereby defining an entry space e of the dimensions a × b for the articles a . the article - orienting unit 30 is particularly suited for the singulation of articles a that are oblong or oblate , with a longest longitudinal dimension β , a shortest transverse dimension α , and an intermediate transverse dimension δ that is greater than α but less than or equal to β ( see fig4 a - 4 c ). in one embodiment , the distance a is greater than a but less than the smaller of δ and two times α . in this embodiment , the distance b is greater than δ but less than the smaller of β and two times δ . in this configuration , the articles a can fit in the entry space e in only one orientation ( that shown in fig5 a , in which the dimension α is generally parallel to the distance a ). in another embodiment , the distance a is greater than α and δ , but is less than two times α . in this second embodiment , the distance b is greater than δ but is less than the smaller of β and two times α . in this configuration , the article a can fit in the entry space e in any orientation in which β is perpendicular to the distances a , b of the entry space e . those skilled in this art will recognize that other configurations for singulating articles may be suitable . the design and dimensions of an alternative article - orienting unit should be chosen to prevent more than one article a entering the exit channel 20 at once . furthermore , objects whose three dimensions are substantially equal ( i . e . spheres ) will also pass through the orienting device achieving the desired singulation . exemplary articles include comestibles such as candies and breath mints , machine components sucha as bolts , nuts and other fasteners , valuables such as diamonds and other gemstones , vitamins , and the like . it may also be understood that an article - orienting device may be attached at the outlet 22 , with the result that the device 10 may singulate in both directions . in operation , the device 10 begins with the valves 29 a , 29 b of the forward and rear jet chambers 24 , 25 closed ( as directed by the controller 40 ), such that the pressure source 28 does not provide jets through the jet apertures 26 a , 26 b , 27 or through the jet aperture 18 a ( see fig3 a and block 200 of fig8 ). the blower 17 is activated and creates a low - level negative pressure with respect to ambient air pressure , causing ambient air to be drawn into the housing 11 through the bottom screen 15 and onto the articles a , thereby suspending ( agitating or fluidizing ) them . the air then passes out through the top screen 16 and past the blower 17 . this agitation gives the articles a fluid flow characteristics within the housing 11 ( block 210 ). the individual articles a travel randomly about the interior of the housing 11 , or can be made to mimic specific fluid flow patterns if desired . in addition , airflow is established from the exterior of the device 10 backward through the exit channel 20 , inward to the housing 11 , and out the top screen 16 to the blower 17 . this airflow pattern prevents articles a from spilling out of the housing 11 into the exit channel 20 . those skilled in this art will recognize that other techniques for preparing articles for singulation may also be employed with the present invention . for example , articles in the housing may be mechanically agitated through known techniques . when the controller 40 requests the dispensing and counting of articles , the controller 40 signals the forward jet chamber valve 29 a to open , and a forwardly - directed air jet is generated through the forward jet apertures 26 a , 26 b ( see fig3 b and block 220 of fig8 ). this activity creates a net outward flow of air from the housing 11 through the exit channel 20 . preferably , the jets apply a pressure of between about 1 and 500 pounds per square inch into the exit channel 20 . one skilled in the art will recognize that a number of different variable pressure control methods may be used for a given pressure pulse through a jet , depending on the effect desired ( for example to match the impedance of the object in the channel ), including simple square waves , sawtooth , sinusoidal , or complex pressure waveforms . in addition , the controller 40 may signal the valve 18 a to open so that the jet nozzle 18 emits a jet ( preferably of about 1 to 500 psi ) that urges articles toward and through the exit channel 20 ( block 230 of fig8 ). in the case where 26 and 27 are only used a vacuum is induced at the entry space e , with the result that articles a within the influence of this induced airflow are drawn to the article - orienting unit 30 . in the case where only the jet nozzle 18 is used , the high - speed air impinging on the object propels it towards and through the exit channel . of course one skilled in the art will realize that jets 26 and 18 may be used in concert . as the articles a are drawn to the entry space e at the entrance to the exit channel 20 , their orientation determines whether they are able to travel through the article - orienting unit 30 . if an article a is oriented generally parallel to the air flow path with its shortest dimension α generally parallel with dimension a of the entry space e ( see fig5 a ), it is able to fit between the panels 31 a , 31 b , the panel 32 and the channel wall 20 a and is , therefore , free to travel into the exit channel 20 . if an article a is oriented perpendicular to the air flow path and generally parallel to panel 32 ( see fig5 b ), it strikes the upstream ends of the panels 31 a , 31 b ( and therefore cannot enter the exit channel 20 ) and rebounds back into the housing 11 to be further agitated . if an article a is oriented perpendicular to the air flow path and parallel to the panels 31 a , 31 b ( see fig5 c ), one end of the article a can strike either the panel 32 or the wall 20 a of the exit channel 20 ( as is illustrated in fig5 c ). contact with the panel 32 or of the wall 20 a causes the article a to rotate about 90 degrees to a position parallel to the air flow path , thereby automatically orienting the article a such that it is free to enter the exit channel 20 . notably , the article - orienting unit 30 is sized and configured so that only one article a can pass through the article - orienting unit 30 at a time . consequently , articles a enter the exit channel as an endwise ( or edgewise ), single - file stream . referring now to fig3 b , once an article a passes into the exit channel 20 ( block 240 of fig8 ), the air flow velocity induced by the jet exiting the forward jet aperture 26 a increases and thus the article a tends to accelerate with that airflow ( block 250 of fig8 ). further along the exit channel 20 , the article a encounters that jet directly and so achieves a higher acceleration . still further downstream in the exit channel 20 , the article a encounters the second jet exiting the forward jet aperture 26 b and experiences even higher acceleration . through each of these stages , the interval between successive articles a is increased . those skilled in the art will recognize that operating with only one forward jet may achieve adequate results . as the articles a continue through the exit channel 20 , they pass the sensor 23 , where the articles a are detected and counted ( block 260 of fig8 ). the increased interval created by the multiple acceleration stages encourages accurate counting of the articles a . also , the inability of the exit channel 20 to permit the passage of more than one article a at a time at any single point in the exit channel 20 ( i . e ., the articles a cannot pass “ side - by - side ” through the exit channel 20 ) also assists the sensor 23 in distinguishing one article a from the next . the sensor 23 signals the controller 40 with the passage of each article a so that the controller 40 can count the number of articles a that have passed thereby and compare that number to a predetermined number ( block 270 of fig8 ). those skilled in this art will recognize that , although it is preferred that the sensor 23 be positioned downstream of the forwardly - directed jet apertures 26 a , 26 b , other locations for the sensor 23 on the exit channel 20 may also be suitable for use with the present invention , and that more than one sensor may be used . after the articles a have passed the outlet 22 , they eventually reach a point that they are no longer under the influence of the jet flows or low - pressure flow . they are then free to travel to a receiving container ( not shown ). the process described above continues until the controller 40 determines that a predetermined number of articles has passed the sensor 23 , at which point the controller 40 signals the valve 29 a to close , which deactivates the forward jets ( block 280 of fig8 ), and signals the valve 29 b to open to generate a reverse jet from the rear jet aperture 27 ( see fig3 c and block 290 of fig8 ). the controller 40 also signals the valve 18 a if present to close in order to cease the production of the jet from the nozzle 18 . the momentum of the articles a that have passed the sensor 23 propels them out of the exit channel 20 and into the receiving container . articles a that have not yet reached the sensor 23 , however , reverse direction due to the reverse flow created by both the reverse jet and the sub - ambient pressure generated by the blower 17 . consequently , they return to the housing 11 through the article - orienting unit 30 ( aided by the fact that the cross - section of the lumen 21 of the exit channel 20 prevents the articles a from re - orienting ). this reversal of direction of the articles a is also assisted by the interval created by the multiple acceleration stages described earlier . in some embodiments , the housing 11 may even be filled with articles a through the outlet 22 via the suction provided by the blower 17 and the rearward jet 27 . another aspect of this invention is that it some instances it may operate adequately without the orienting device . in this case , the controller 40 may be used to detect jams at the entrance to the exit channel ( by dint of the lack of passage signals at sensor 23 ) and so the forward and reverse jets may be pulsed off and on to clear the jam . typically , this is will reduce the overall speed of the system but that may be an acceptable trade in certain applications . those skilled in this art will recognize that other designs for components of the device 10 may be suitable for use with the present invention . for example , the article - orienting unit 30 ′ may take the configuration of that illustrated in fig7 a and 7b , which lacks a plate 32 . also suitable is the configuration of an article - orienting unit 100 shown in fig6 a and 6b . the article - orienting unit 100 includes a pair of hinged panels 110 that pivot about a pivot axis 111 that is parallel with the flow axis of the exit channel 20 . the hinged panels 110 and the wall 20 a of the exit channel 20 define an entry space e ′ that is generally wedge - shaped and that can , depending on the shape of the article a only permit a single article a to pass therethrough at a time , and to do so in a preferred orientation . one skilled in the art will recognize that the downstream ends of the panels 110 may extend most or all the entire length of the lumen 21 . one advantage of this configuration is the capability of one or both of the panels 110 to pivot relative to one another to adjust the size of the entry space available to the article a , thereby enabling the device 100 to be used on batches of articles that vary in size from batch to batch . the foregoing is illustrative of the present invention , and is not to be construed as limiting thereof . although exemplary embodiments of this invention have been described , those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention . accordingly , all such modifications are intended to be included within the scope of this invention as defined in the claims . the invention is defined by the following claims , with equivalents of the claims to be included therein .