in the following description , numerous specific details are set forth in order to provide a thorough understanding of the various principles of the present invention . it will be apparent to one skilled in the art , however , that not all these details are necessarily always needed for practicing the present invention . in this instance , well - known circuits , control logic , and the details of computer program instructions for conventional algorithms and processes have not been shown in detail in order not to obscure the general concepts unnecessarily . other systems , methods , features and advantages will be , or will become , apparent to one with skill in the art upon examination of the following figures and detailed description . it is intended that all such additional systems , methods , features and advantages be included within this description , be within the scope of the invention , and be protected by the following claims . nothing in this section should be taken as a limitation on those claims . further aspects and advantages are discussed below . subject matter will now be described more fully hereinafter with reference to the accompanying drawings , which form a part hereof , and which show , by way of illustration , specific example embodiments . subject matter may , however , be embodied in a variety of different forms and , therefore , covered or claimed subject matter is intended to be construed as not being limited to any example embodiments set forth herein ; example embodiments are provided merely to be illustrative . likewise , a reasonably broad scope for claimed or covered subject matter is intended . among other things , for example , subject matter may be embodied as methods , devices , components , or systems . accordingly , embodiments may , for example , take the form of hardware , software , firmware or any combination thereof ( other than software per se ). the following detailed description is , therefore , not intended to be taken in a limiting sense . throughout the specification and claims , terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning . likewise , the phrase “ in one embodiment ” as used herein does not necessarily refer to the same embodiment and the phrase “ in another embodiment ” as used herein does not necessarily refer to a different embodiment . it is intended , for example , that claimed subject matter include combinations of example embodiments in whole or in part . in general , terminology may be understood at least in part from usage in context . for example , terms , such as “ and ”, “ or ”, or “ and / or ,” as used herein may include a variety of meanings that may depend at least in part upon the context in which such terms are used . typically , “ or ” if used to associate a list , such as a , b or c , is intended to mean a , b , and c , here used in the inclusive sense , as well as a , b or c , here used in the exclusive sense . in addition , the term “ one or more ” as used herein , depending at least in part upon context , may be used to describe any feature , structure , or characteristic in a singular sense or may be used to describe combinations of features , structures or characteristics in a plural sense . similarly , terms , such as “ a ,” “ an ,” or “ the ,” again , may be understood to convey a singular usage or to convey a plural usage , depending at least in part upon context . in addition , the term “ based on ” may be understood as not necessarily intended to convey an exclusive set of factors and may , instead , allow for existence of additional factors not necessarily expressly described , again , depending at least in part on context . turning now to the drawings , reference is initially made to fig1 , which is a semi - schematic diagram of a smoking device 10 in accordance with an embodiment of the invention . device 10 has a battery section 12 . the battery section 12 may include power controls . suitable power controls are disclosed in u . s . provisional application no . 61 / 441 , 133 ( now us pat . pub . no . 2013 - 0319440 a1 ), which is herein incorporated by reference . the device 10 includes a section 14 , containing an atomizer and an aerosolizable liquid or gel , sometimes referred to herein as an “ e - liquid ”, which typically contains a mixture of propylene glycol , vegetable glycerin , flavorings . and optionally contains nicotine . the atomizer is essentially a heating element , powered by a battery in the battery section 12 . when powered , the atomizer acts on the liquid or gel . the components of the section 14 may be provided as separate components , or may be integral , as taught in u . s . provisional application no . 61 / 474 , 569 ( now us pat . pub . no . 2014 - 0034071 ), which is herein incorporated by reference . in the latter case , the section 14 is known as a “ cartomizer .” an adapter 16 for receiving a tobacco - containing unit 18 is disposed at one end of the device 10 in a longitudinal fashion , so that the device 10 , when docked with the unit 18 , may appear to observers as an actual cigarette . the unit 18 may be a cigarette , a nicotine pack or cartridge , a hookah , or other source of tobacco fumes . in any case , a first air intake for receiving tobacco fumes is represented by arrow 20 . when smoke enters the device 10 , an aperture 22 constricts the flow , thereby creating a pressure differential , which is sensed by an airflow sensor 24 of known type . it is desirable to minimize the flow resistance , for example by minimizing flow constriction , in order that that the user experiences a feeling of smoking an actual cigarette . there is a tradeoff , however , in that the energy transmitted by pressure differences resulting from the inhalation is used to create the atomizer action . for a given pressure difference and flow conditions the ability to release droplets is also dependent on the viscosity of e - liquid . e - cigarettes use a high viscosity liquid that is converted to a low viscosity by heating . electronic circuitry 26 linked to the sensor 24 activates a heating device that enable viscosity reduction and thus activation of the atomizer in the section 14 . part of this electronic circuitry is a pressure or flow sensor , which switches a power source when the smoker starts inhaling . the circuitry 26 is powered , typically by an electrical power source ( single use or rechargeable ), for example , a lithium ion battery 28 , other known type of rechargeable battery , or alternatively by a super capacitor . additionally or alternatively . the aperture 22 may be manually controlled by the user by pressing a button ( not shown ), which can be mounted on the shaft of the device 10 . for convenience , the device 10 may be configured similarly to a pistol , the actuating button corresponding to the trigger . a second air intake is formed through the device 10 as a side vent 30 . the vent 30 may be created in several ways , for example as a longitudinal notch , a hole bored through the shaft of the device 10 , or formed in an adapter connecting the section 14 and the battery section 12 as taught in the above noted u . s . provisional application no . 61 / 474 , 569 . a regulated three - way mixing valve 32 accepts air inflow via the first air intake ( arrow 20 ) and from the second air intake ( vent 30 ). air exiting the valve 32 represented by arrow 34 contains a mixture of the two inflows in any desired proportion . the inflows may be controlled at constriction points 45 , 47 . as a result the user inhales , through oral adaptor 36 ( arrow 38 ) an air mixture containing from 0 - 100 percent tobacco fumes . the valve 32 may be programmed by electronic circuitry 40 within the device 10 . for example , initial puffs may contain 100 % tobacco fumes . thereafter the valve adjusts automatically to limit the proportion of smoke . alternatively , a control 42 may be provided for the user to manually adjust the valve 32 . the circuitry 40 or the circuitry 26 may disable the atomizer in the section 14 when the proportion of tobacco fumes exceeds a predefined threshold . the valve 32 , vent 30 , air flow sensor 24 , and other components need not be positioned as shown . for example they may be relocated upstream in the first air flow , and be placed before the battery 28 . other locations are possible , but in any case the user inhales a desired proportion of air and tobacco fumes . in some embodiments , a conventional cigarette may be smoked in combination with or in alternation with the e - cigarette . in such cases the air stream resulting from the conventional cigarette should be diverted to bypass the atomizer , as explained below . reference is now made to fig2 , which is a semi - schematic diagram of a smoking device 64 in accordance with an alternate embodiment of the invention . the general construction of the smoking device 64 is similar to the device 10 ( fig1 ). however the valve 32 is disposed downstream ( in the direction of inhaled airflow ) from the atomizer in the section 14 . the battery 28 , particularly when realized as a lithium ion battery , has several disadvantages . charging and discharging must be carefully regulated . in addition , precautions must be taken to prevent contact with liquid in the section 14 , should leakage occur . indeed , under some circumstances the battery 28 could be a fire hazard . in addition , charging times limit the utility of the device 10 , or may require the user to carry duplicates of the battery section 12 or the battery 28 . reference is now made to fig3 , which is a schematic diagram of a smoking device 46 in accordance with an alternate embodiment of the invention . in this embodiment , the battery 28 is replaced by a super capacitor 44 , which can be charged within seconds by connection to ordinary house power . the device 46 is provided with intakes 58 , 60 for air and tobacco fumes . the capacitance of the capacitor 44 is sufficient to power the atomizer for a desired number of usages before it discharges . reference is now made to fig4 , which is a schematic diagram of a smoking device 48 in accordance with an alternate embodiment of the invention . in this embodiment , the device 48 has a mounting adapter 49 for docking a portion of a conventional cigarette 50 or other source of tobacco fumes longitudinally alongside the housing . the smoke enters through a side vent as described above ( arrow 52 ). ambient air enters through a distal end intake ( arrow 54 ), both reaching mixing valve 56 . it will be noted that an air stream represented by arrow 54 passes through an atomizer 57 , while the air stream from the cigarette 50 does not enter the atomizer 57 . in this embodiment the air intake is regulated by valves at the intakes , or alternatively , by a mixing valve located at the intake , which can be an electronically controlled valve , or any other type of valve as explained elsewhere herein . reference is now made to fig5 , which is a semi - schematic diagram of a smoking device 66 in accordance with an alternate embodiment of the invention . in this embodiment , the aperture 22 ( fig1 ) has been replaced by a shutter valve 68 . the vent 30 is guarded by another shutter valve 70 . the shutter valves 68 , 70 have the same construction , as best seen in balloons 72 , 74 . alternatively , the two shutter valves may differ in construction . in any case , the combined flows exit toward the oral adaptor 36 via outlet tube 76 as shown by the arrow 34 . in the shutter valves 68 , 70 , an air shutter 62 is slidable over intake 58 to restrict air flow therethrough . the shutter 62 may be controlled manually by the user , or automatically by a controller 78 to adjust the relative flows through inlet tubes 80 , 82 . the shutters shown in fig5 are exemplary . other closure arrangements , e . g ., hinged valves , electronically controlled valves , cam driven piston valves , can be substituted for the shutter valves 68 , 70 . several such alternatives are described in the embodiments below . indeed the shutter valves 68 , 70 can be used as regulatory elements in the valve 32 ( fig1 ). reference is now made to fig6 , which is a semi - schematic diagram of a smoking device 84 , in accordance with an alternate embodiment of the invention . in this embodiment the valve 32 ( fig1 ) is realized as a ball valve 64 , in which air outflow may be allocated in any desired proportion between an outlet 86 leading to a vent 88 and an outlet 90 leading toward the oral adaptor 36 . ball valves typically have low maintenance costs . in addition to affording quick , quarter - turn on - off operation , ball valves are compact , require no lubrication , and give tight sealing with low torque . however , they have relatively poor throttling characteristics . in a throttling position , the partially exposed seat is vulnerable to erosion because of the impingement of high velocity flow . a first air stream , represented by arrows 20 , is diverted from the atomizer by shutter valve 23 , and reaches the ball valve 64 . a second air stream , represented by arrows 25 enters via aperture 21 , passes through the atomizer 57 and thence to the ball valve 64 . thus mixing occurs in the ball valve 64 downstream from the atomizer 57 , after it has acted on the second air stream . reference is now made to fig7 . which is a schematic diagram of illustrating operation of a simplified ball valve 92 that facilitates understanding of the ball valve 64 ( fig6 ), in accordance with an embodiment of the invention . fluid flow direction is indicated by the arrows in fig7 . from left to right , the ball valve 92 is shown in open , throttled , and closed positions , respectively . the ball valve 92 has a body 94 and a ball 96 , an inlet 98 and a single outlet 100 . in this respect the ball valve 92 is unlike the ball valve 64 , which has two outlets 86 , 90 . the ball 96 rotates about an axis 102 , under control of an actuator 104 . reference is now made to fig8 , which is a semi - schematic diagram of a smoking device , in accordance with an alternate embodiment of the invention . in this embodiment , mixing occurs after a portion of the airflow has passed through the atomizer . a bypass tube 106 transmits a proportion of the air flow , the proportion being regulated by the control 42 at a constriction point 108 , while the remainder of the airflow passes through the atomizer via tube 110 , as shown by arrow 112 . when the constriction point 108 is fully open , the atomizer offers greater flow resistance than the bypass tube 106 , and most of the flow passes through the bypass tube 106 . actuating the control 42 constrains flow through the bypass tube 106 at the constriction point 108 , so that a greater proportion of the flow arrives at the vent 30 by passing through the atomizer and the tube 110 . providing a parallel flow circuit via the bypass tube 106 allows the total flow resistance to be lowered . the arrangement shown schematically in fig8 may be applied , mutatis mutandis , to any of the other embodiments disclosed herein . reference is now made to fig9 , which is a schematic diagram of a valve 114 in accordance with an embodiment of the invention . the valve 114 can be employed in the various embodiments herein , for example at the constriction points 108 , 45 ( fig8 ). movement of a ball ( or cylinder ) 116 against the wall of a tube 118 produces compression and increases flow resistance . reference is now made to fig1 , which is a schematic diagram of a diaphragm valve 120 , in accordance with an embodiment of the invention , wherein displacement a diaphragm 122 by an actuator 124 into the flow throttles or obstructs the flow entirely . from left to right the diaphragm valve 120 is shown in open , throttled , and closed positions , respectively . the diaphragm valve 120 can be used in the various embodiments herein , for example at the constriction points 108 , 45 ( fig8 ). it will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove . rather , the scope of the present invention includes both combinations and sub - combinations of the various features described hereinabove , as well as variations and modifications thereof that are not in the prior art . which would occur to persons skilled in the art upon reading the foregoing description . the illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments . the illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein . many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure . other embodiments may be utilized and derived from the disclosure , such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure . additionally , the illustrations are merely representational and may not be drawn to scale . certain proportions within the illustrations may be exaggerated , while other proportions may be minimized . accordingly , the disclosure and the figures are to be regarded as illustrative rather than restrictive .
in an electronic cigarette of the sort having a housing , a power section , and an atomizer , at least a portion of a first flow stream passes through the atomizer . a mixing valve within the housing has a first input that receives the first flow stream , and a second input receiving a second flow stream that avoids the atomizing element , and an output connected in fluid continuity to the opening in the proximal end , wherein the output conducts a mixture of the first flow stream and the second flow stream . the apparatus further includes a regulating element for the mixing valve in order to control a composition of the mixture .