Abstract:
In a vapor delivery device, a carrier or an expedient for an active ingredient is a liquid that can be vaporized by exposure to a concentrated, focused heating point using an efficient electrical power source. The device may have a vaporizing element and an electrical power source in a housing. A switch controls supply of electrical power to the vaporizing element from the electrical power source. A tube connects a liquid reservoir to the vaporizing element. A first valve, a second valve, and a pump are generally associated with the tube. A lever pivotally supported on or in the housing may be positioned to operate the first valve, the second valve, the pump and the switch, via pivoting movement of the lever. The device efficiently provides a uniform dose of vapor with each actuation.

Description:
BACKGROUND OF THE INVENTION 
     The field of the invention is vaporizing a liquid for inhalation. Various vaporizing devices have been used in the past. Still, disadvantages remain in the design and performance of vaporizing devices. These include variations in the dose of vapor delivered and leakage or performance failures unless the vaporizing device is maintained in an upright position during use, or during the packaging, shipping and storage of the device. In addition, with some vaporizing devices, the liquid may be subject to contamination, adulteration and/or evaporation under certain conditions. 
     Accordingly, it is an object of the invention to provide an improved vapor delivery system. 
     SUMMARY OF THE INVENTION 
     In one aspect, a vapor delivery device may have a vaporizing element and an electrical power source in a housing. A switch controls supply of electrical power to the vaporizing element from the electrical power source. A tube connects a liquid reservoir to the vaporizing element. A first valve, a second valve, and a pump are generally associated with the tube. A lever pivotally supported on or in the housing may be positioned to operate the first valve, the second valve, the pump and the switch, via pivoting movement of the lever. Other and further objects and advantages will become apparent from the following detailed description, which provides examples of embodiments of the invention. Persons of ordinary skill will readily be led to other additional examples of the invention that are not specifically described here, but are still intended to be within the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a new vaporizing device. 
         FIG. 2  is a top view of the device shown in  FIG. 1 . 
         FIG. 3  is a section view taken along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is an enlarged detail section view of the upper section of the device. 
         FIG. 5  is an exploded perspective view of the device shown in  FIGS. 1-4 . 
         FIG. 6  is an enlarge perspective view of elements of the device shown in  FIGS. 3-5 . 
         FIG. 7  is a perspective view of an alternative design, with the housing removed for purpose of illustration. 
         FIG. 8  is an exploded perspective view of the design shown in  FIG. 7 . 
         FIG. 9  is an enlarged side view showing details of elements shown in  FIGS. 7 and 8 . 
         FIGS. 10-13  are side views of the device shown in  FIGS. 7-9  illustrating sequential steps of operation. 
         FIG. 14  is an enlarged perspective view of the vaporizing system shown in  FIGS. 7-9 . 
         FIG. 15  is a schematic diagram of a “one-shot” circuit that may be used in the devices described below. 
         FIG. 16  and  FIG. 17  are schematic diagrams of similar modified circuits. 
         FIG. 18  is an enlarged side view of an alternative vaporizing element. 
         FIG. 19  is a perspective view of an alternative vaporizing device. 
         FIG. 20  is a section view of the vaporizing device shown in  FIG. 19 . 
         FIG. 21  is an exploded perspective view of the vaporizing device shown in  FIGS. 19 and 20 . 
         FIG. 22  is an enlarged perspective view of elements shown in  FIG. 20 . 
     
    
    
     DETAILED DESCRIPTION 
     Turning now in detail to the drawings, as shown in  FIGS. 1 and 2 , a vaporizing device  20  has an elongated housing  22  with a mouthpiece  24  and a lever  28  adjacent to a back or top end of the housing. A mouthpiece opening  26  extends into the mouthpiece  24 . Referring further to  FIGS. 3-5 , the device  20  includes a liquid delivery system  30  and a vaporizing system  32 , as well as an electrical power system  34 . The electrical power system  34  may include batteries  44  within a battery compartment  42  of the housing  22 , and with the batteries electrically connected to a flexible circuit board  82  via a spring  46  and contacts  48 . As shown in  FIG. 5 , the housing may be provided with left and right sides, in a clamshell design. The lever  28  may be attached to the housing  22  at a pivot  58 . 
     As shown in  FIG. 4 , the liquid delivery system  30 , in the example shown, includes a resilient or flex wall liquid chamber or reservoir  64  connected via a tube  66  to a lever valve  70 . The reservoir  64  may be a thin walled flexible pouch made of polyethylene film. The reservoir  64  is positioned between two rigid surfaces, with a plate  62  on one side and an inner wall of the housing  22  on the other side. Springs  60  within the housing  22  press on a plate  62 , which in turn presses on the reservoir  64 . This pressurizes the liquid in the reservoir. 
     A tube  66  extends from the reservoir  64  to a lever valve  70  which may include a valve post  74 , a valve spring  72  and valve washer  76 . A valve section  80  of the tube  66  in this design extends through an opening the valve post  74 , as shown in  FIG. 6 . The valve spring  72  urges the valve washer  76  against the valve section  80  of the tube pinching it closed. 
     Referring to  FIGS. 4-6 , the vaporizing system  32  includes a heater  150  which is electrically connected to the electrical power system  34 . The vaporizing system  32  is also connected to, and receives liquid from, the liquid delivery system  30 . The heater  150  may be an electrical resistance heater formed with by an open coil of wire  152 , such as ni-chrome wire. In this design, the electric current is supplied to the coil  152  via connectors  156  on, or linked to, the flexible circuit board  82 , which in turn in connected to the batteries  44 .  FIG. 14  shows the connectors  156  for providing electrical power to the heating element. 
     In use, the mouthpiece  24  is placed into the mouth and the user presses or squeezes the lever  28 . The tube  66  is pre-filled or primed with liquid during manufacture. Referring to FIG.  4 , as the lever  28  pivots down about the pivot  58 , a pincher  86  located on a first section  90  of the lever  28  pivotally attached to the housing pinches the pump segment  67  of the tube  66  against an inside surface of the housing  20 , adjacent to the pivot  58  and the reservoir  64 . This temporarily closes off the tube  66  at the pincher  86 . As the lever  28  continues to pivot down (or inward towards the centerline of the device) a ramp surface  88  on a second section  92  of the lever  28 , flexibly attached to the first section  90  progressively squeezes the pump segment  67  of the tube  66  between the pincher  86  and the lever valve  70 . This creates a squeegee type of movement which pumps liquid towards the lever valve  70  using a peristaltic action. As the lever  28  continues to pivot inwardly, posts on the lever press the valve washer  76  down against the force of the valve spring  72 . This temporarily opens the lever valve  70  by allowing the valve section  80  of the tube  66  to open. With the valve section  80  of the tube open, and with liquid in the tube being pumped via the ramp surface  88 , a bolus of liquid flows through the valve section  80  and the outlet segment  154  and into the wire coil  152 . 
     An outlet segment  154  of the tube  66  extending out of the lever valve  70  towards the mouthpiece or back end of the device is inserted into the front end of a wire coil  152 . Referring momentarily to  FIG. 14 , solid wire inserts  159  may he inserted into the ends of the wire coil  152  and the outlet segment  154  to provide internal support, so that they do not distort or collapse when pressed down into connectors  156 . The outlet segment  154  at the front end of wire coil heater  152  provides liquid into the bore of coil with each actuation of the device  20 . 
     The tube  66  is connected to the reservoir  64  with a liquid-tight connection so that liquid can only flow from the reservoir only through tube  66 . The tube  66  may be a resilient, flexible material such that its inner lumen can in general be completely flattened when compressed, and then generally recover to its original shape when released. A pump segment  67  of the tube  66  is positioned beneath the lever  28  and a fixed surface inside of the housing, which optionally may be part of the circuit board  82  that power management circuitry, is on. Locating features  112  may be provide in, on, or through the circuit board  82  to ensure desired positioning is maintained. The lever  28  is retained by lever pivot  116  and can pivot through a controlled range of motion. 
     The constant positive pressure exerted on the reservoir  64  by the springs  60  pressurizes the liquid in the tube  66 . However, since the tube  66  is pinched closed by the pincher  86 , no liquid flows out of the reservoir when the lever is depressed and the lever valve is opening. Rather, the liquid already present in the tube  66  between the pincher  86  and the lever valve  70  provides the measured bolus which is uniformly delivered to the wire coil. 
     The downward movement of the lever  28  also closes a switch  158  linked to or located on the circuit board  82 . Electric current then flows from the batteries  44 , or other power source, to the wire coil  152 . The wire coil heats up causing the liquid to vaporize. The current supplied to the wire coil, and the temperature of the wire coil when operating, may be regulated by the circuit board, depending on the liquid used, the desired dose, and other factors. The switch  158  may be positioned to close only when the lever  28  is fully depressed. This avoids inadvertently heating the wire coil. It also delays heating the wire coil until the bolus of liquid is moved into the wire coil via the pivoting movement of the lever, to help prolong battery life. A “one-shot” control circuit, for example as shown in  FIG. 15  described below, may be used to limit the electric current delivery time interval regardless of how long the user holds the lever down. The power delivery system  34  is completely “off” in between uses. There is no drain on the battery during idle time. As a result, battery life is prolonged. 
     As is apparent from this description, the liquid delivery system  30 , using a linear peristaltic pumping action, delivers a fixed, repeatable bolus of liquid to vaporizing system  32  with each actuation of the device  20 . The liquid delivery system  30  further seals the reservoir  64  between actuations via the pincher  86 , maintains the contents of the reservoir in a pressurized state, and controls electric power delivery to the vaporizing system  32 . The liquid delivery system is designed so that as liquid is used, air is not introduced into the system. 
     The diameter and length of the wire coil  152  forms a cylindrical volume within the inside diameter of the coil that is sufficient to capture a single expressed dose of liquid from the liquid delivery system. The adjacent loops of wire of the wire coil  152  may also be positioned so that liquid surface tension holds the liquid within the bore of the coil. This allows the device  20  to be used in any orientation, since gravity is not needed to keep the released dose of liquid in place. 
     The use of an open coil offers the further advantage that the vapor may be generated and escape anywhere along the length of the coil, without inadvertently affecting vaporization of the balance of the bolus of liquid in the coil. The wire coil also provides a large surface area for heat transfer and minimizes energy loss resulting from heating ancillary components. 
     Upon application of electric power, liquid in the coil vaporizes and passes through gaps between coils. The coil can be sized and shaped and positioned in the housing so that the vapor generated can be entrained into an air stream drawn through the device  20  when the user inhales on the mouthpiece. Inhale here means drawing the vapor at least into the mouth. 
       FIGS. 7-13  show a second device embodiment  100  which may be similar to the device  20 , but with the following differences. In the device  100 , a foam pad  27  is compressed and inserted between a reservoir  64  and one of the rigid walls of the housing. Force exerted on the reservoir  64  by the foam trying to recover to its relaxed state exerts compressive force on the reservoir which maintains the liquid in the reservoir under pressure. The foam pad  27  may be used in place of the springs  60  shown in  FIG. 4 . The reservoir may alternatively be pressurized using a syringe with a spring biased plunger. With this design, the reservoir may optionally be provided as a replaceable cartridge. 
     As shown in  FIG. 8 , in the device  100 , a lever valve  118  is provided (in place of the pincher  86  in the device  20 ) to compress the front end of the tube  66 , preventing liquid from flowing out from the pressurized reservoir in between uses. The lever valve  118  may be a stamped sheet metal form soldered to a rigid circuit board  114 . 
       FIGS. 10-13  show the pumping action of the liquid delivery system in the device  100 . When a dose of vapor is desired, the user places the mouthpiece in the mouth and inhales while pressing a button  109  on the lever  110 , causing the lever to rotate downward (counter-clockwise). As the lever  110  initially rotates as shown in  FIG. 10 , a lever pinch projection  132  clamps or pinches the tube  66  closed at a pinch point  140 , closing off the pressurized liquid reservoir. Continued rotation of lever  110  causes the lever  110  to flex at a flex point  124  having reduced thickness, as shown in  FIG. 11 . This allows over-travel rotation of the lever while the tube  66  remains closed off at the pinch point  140 , without crushing the tube. 
     Further rotation of lever  110  then compresses the lumen of the pump segment  67  of the tube  66 . This pumps liquid from the pump segment  67  towards the lever valve  118 . This movement also moves projections on the lever which push valve flanges  120  down, deflecting and opening the lever valve  118 , and allowing a pressurized bolus of liquid to move through the tube and into the vaporizing system  32 . The dotted lines in  FIG. 12  show the lever valve  118  deflected down and away from the bottom surface of the circuit board  114 , to open the valve. Lastly, at end of the lever stroke, a lever switch protrusion contacts a switch  158 , switching the power delivery system on. 
     When lever  110  is released, it pivots back up to its original position. As the lever returns, the lever valve  118  reseats first, sealing the back end of pump segment  67  of the tube  66  and preventing air from being drawn back into the pump segment. As the lever  110  continues to rotate clockwise, the pump segment  67  decompresses, creating a negative pressure within the tube lumen. Lastly, at pinch point  140  the tube  66  reopens, allowing pressurized liquid from the reservoir to enter, refilling pump segment with liquid to provide the next dose. 
     The volume of liquid expressed with each stroke can he controlled by selection of desired pump segment  67  tube diameter and length. Maintenance of a positive pressure on the liquid reservoir ensures that the system always stays primed with liquid, and that “short shots” resulting from air bubbles in the tube do not occur. Furthermore, sealing of the vaporizer system with a valve such as the valve  70  or  118  that is only actuated at the time of delivery, and positive pressure dispensing prevents inadvertent leakage of liquid irrespective of orientation of the device during storage or use. 
       FIG. 15  is a schematic diagram for a “one-shot” circuit  170  that delivers a fixed time interval of electric current to the heater  150  regardless of how long the lever is depressed by the user. In  FIG. 15 , CD4047 is a CMOS low power monostable/astable multivibrator available for example from Texas Instruments. U 1  is a common CD4047 which operates from a 12V battery voltage with very low quiescent current drain. When pushbutton SW 1  is depressed, U 1  is triggered, Q (pin  10 ) goes high and C 1  is rapidly charged to near the supply voltage through a FET within U 1 . At the same time, resistor R 1  is switched to a logical “0” state and immediately begins discharging capacitor C 1  with the time constant of 1/RC. 
     A wide range of pulse durations may be selected. Using a typical ni-chrome wire coil, pulse durations ranging from approximately 0.2 to 2 seconds are sufficient to fully vaporize the bolus of liquid. When the voltage on pin  3  reaches the threshold for logic “0” (˜⅓ supply voltage), the logic levels switch and Q (pin  10 ) returns to a logic low level. Q 2  is an emitter follower that provides current amplification to enable Q 1  to be fully saturated during the desired current pulse. D 1  and R 4  provide a visual indication of the heater current. R 2  is a “pull down” resistor for SW 1 , and C 2  prevents induced noise from falsely triggering the circuit. Other choices of IC may be employed such as the Toshiba TC7WH123 depending upon battery voltage, package size, and cost. 
     The battery voltage gradually decreases over the lifespan of the device. For many applications, the circuit described in  FIG. 15  provides the necessary control. However, more precise metering of the medicament may be accomplished by increasing the current pulse duration as the current decreases over the discharge life of the battery. In the circuit  172  shown in  FIG. 16 , an additional OP amp IC serves as a voltage controlled current source. The input voltage is sampled from Pin  10  of U 1 . A constant current is generated in Q 3  and used to discharge the timing capacitor, C 1 , at a constant rate. Once the voltage across C 1  reaches the logic threshold, CD 4047 trips and the output pulse width is complete. As the battery voltage decreases the constant current generated in Q 3  decreases, causing the time to discharge C 1  to increase. This lengthens the output pulse to maintain a relatively constant heater power per inhalation cycle as the battery voltage declines over the lifetime of the device. The various current setting and sense resistor values may be adjusted to provide optimal performance. Other circuits may be employed to provide the same function such as voltage to frequency converters. 
       FIG. 17  shows another circuit  174  where a voltage regulator U 2  is inserted between the output transistor Q 1  and the heater filament. This keeps the filament voltage constant throughout the battery life. The regulated voltage may be chosen to optimize the heater operation near end of life. A low dropout regulator is desired to maximize the lifespan before regulation is no longer maintained. A simple linear regulator is shown, but a high efficiency, switching regulator may also be employed to improve efficiency. The pulse duration is maintained as described above or an equivalent “one shot” circuit and the heater current is kept constant by the voltage regulator. 
     In another alternative design, the electrical power system  34  may be configured to provide consistent power by timing the power to provide the minimum energy needed to vaporize the liquid. The power system may also be programmed to do this. For example, the electrical power system may be programmed to power the source down to the voltage required to vaporize the liquid, so as to extend its useful life. Here, the power source may include a capacitor that builds, retains and provides a charge necessary to vaporize the liquid to be vaporized, again, so as to extend the useful life of the power source. 
     In an additional alternative design shown in  FIG. 18 , the liquid to be atomized is delivered into a small diameter tube  180  via capillary action, as distinct from providing the liquid via pressure into the heating coil, where it is stabilized for vaporization due to surface tension. The tube  180  can be glass, polyaniline or metal, e.g., stainless steel. A heating element such as ni-chrome wire can be coiled around the tube, coiled into the tube or inserted into a tube in a V-shape so as to heat the entire volume of liquid at the same time. 
       FIGS. 19-22  show an alternative vaporizing device  200  having a housing formed from a base  202  including a mouthpiece  206 , and a cover  204  attached to the base  202 . Pivot arms  209  on a button  208  are pivotally attached to pivot posts  226  on a bridge  224 , as shown in  FIG. 21 . The radius  244  of the pincher  238  can flex when the tube  236  is compressed. The bridge  224  has pins for securely attaching it to the base  202 . The positive electrode of each battery  44  are held into contact with center contact  212  by a spring  46 . A positive conductor strip connects the center contact to a printed circuit board  216 . 
     Brass posts or similar contacts are attached to the printed circuit board  216  and to opposite ends of the coil  222 . The button  208  has a pincher arm  238  positioned to pinch and close off flow in a tube  236  connecting a liquid reservoir to an outlet location on, adjacent to or overlying the wick  220 . The tube  236  may be held in place by molded in tube clips  242  on the bridge  224 . Arms  233  on a normally closed pinch valve  232  extend up through openings in the bridge  224 . A valve spring  230  around a post  228  holds the valve  232  into the normally closed position. A bottom surface of the valve  232  may act as a switch with the printed circuit board  216 , or actuate a separate switch on the printed circuit board  216 , to switch on electrical current to the coil  222  when the button  208  is pressed. 
     In use, the vaporizing device  200  operates on the same principals as described above, with the following additions. A slot  210  may be provided in the housing to accommodate an insulating tab. The insulating tab is installed during manufacture and prevents electrical contact between the center contact  212  and the batteries. As a result, the device cannot be inadvertently turned on during shipping and storage. Battery life is therefore better preserved. Before operating the vaporizing device  200  for the first time, the user pulls the tab out of the slot  210 . As shown in  FIGS. 19 and 20 , the mouthpiece is round. The dimension LL in  FIG. 20  between the coil  222  and the mouthpiece tip may be minimized to 15, 10 or 5 mm. The liquid reservoir may have a volume exceeding 0.8 or 1.0 ml to allow foam compression to pressurize the pump. In the device  200 , the liquid, supplied from the reservoir via the tube  236  is not delivered into the coil  222 . Rather the liquid is delivered onto to the wick  220 . The heating coil  222  abuts the wick  220  and heats the wick, which then vaporizes substantially all of the liquid on or in the wick. 
     Referring to  FIG. 22 , a wick  220  extends from the printed circuit hoard  216  up to a vaporizing coil  222  and optionally over a raised wall  240 . The wick may be a strip or sheet of ceramic tape  220  that serves as a wick and a heat sink. The wick  220  is positioned between the heating element, such as the vaporizing coil  222 , and the outlet of the tube  236 . The wick  220  may rest on top of the heating element, or be positioned adjacent to it, and the tube outlet may also be on top of the heating element and the wick  220  (when the device  200  is in the upright position, with the button  208  on top). 
     In each of the vaporizing devices described above, the open coil heater  152  or  222  of e.g., ni-chrome wire may be encased in a porous ceramic material, so that the vapor produced when the fluid is atomized must pass through the ceramic material in order to be ingested. The ceramic material can be manufactured with techniques that control the size of the pores through which the vapor will pass. This can help to regulate the size of the vapor molecules or droplets produced for inhalation. By controlling the amount of electrical power and the duration of power to the coil heater, the heater continues to vaporize the fluid at the heater until the vapor droplets or particles are small enough to pass through the ceramic material, effectively utilizing all the fluid delivered to the coil and controlling the dose in addition to regulating the molecule size. By regulating the size of the vapor molecule produced, the vaporizing devices can be used with more precision and with fluids and medicaments that require carefully controlled dosages particle sizes. In some cases, smaller molecules may be advantageous as they can be inhaled more deeply into the lungs, providing better a more effective delivery mechanism. 
     The wire coil heater may alternatively be encased in a heat resistant fabric-like material, so that the vapor must pass through the fabric to be ingested. The fabric can be manufactured with a desired mesh opening size, better regulate the size of the vapor particles delivered by the vaporizer. By, by controlling the amount of electrical power and the duration of power to the heater, the heater continues to vaporize the fluid delivered to the heater until the vapor particles are small enough to pass through the mesh of the fabric. This can help to effectively atomize and deliver all the fluid delivered to the heater, with little or no waste, in turn controlling the dose. 
     Although the switch  158  is described above as a mechanical contact switch, other forms of switches may optionally be used, including switches that optically or electrically sense the movement of position of an element, or a switch that senses the presence of liquid in the heater  150 . In addition, though the lever and pinch valves are shown as clamping type of valves, other forms of mechanically or electrically operated valves may be used. Similarly, the peristaltic pumping action created by the pivoting movement of the lever may be optionally replaced with alternative forms of pumping or fluid movement. Various types of equivalent heating elements may also be used in place of the wire coils described. For example, solid state heating elements may be used. The heating element may also be replaced by alternative vaporizing elements, such as electro-hydrodynamic or piezo devices that can convert liquid into a vapor without heating. Thus, multiple embodiments and methods have been shown and described. Various modifications and substitutions may of course be made without departing from the spirit and scope of the invention. The invention, therefore, should not be limited except by the following claims and their equivalents.