Environmentally controlled vending machine for humidity sensitive products

An environmentally controlled vending machine utilizing real-time monitoring of environmental parameters and feedback control for improved storage conditions for tobacco products such as cigars and other humidity sensitive products, is disclosed. A number of environmental parameters, such as temperature and humidity, are balanced using a closed loop feedback control process in response to measured system parameters. The vending machine includes a controller, one or more remote sensors which monitor the environmental conditions within the vending machine housing, a fan, a heater strip, a cooling unit, a humidifier, and a payment and selection system. The vending machine stores and maintains tobacco products, or other humidity sensitive products, at a recommended temperature and humidity, and includes means for continuously monitoring and controlling the environment to retain the freshness and value of the respective product. In order to best maintain the freshness and value of the tobacco products, for example, the vending machine preferably stores the products at approximately 70.degree. F. and a relative humidity of approximately 70%.

FIELD OF THE INVENTION 
The present invention relates to vending machines, and more particularly, 
to a vending machine for humidity sensitive products, such as tobacco or 
cosmetic products, which is capable of monitoring and adaptively 
controlling internal environmental parameters. 
BACKGROUND OF THE INVENTION 
In this age of convenience and twenty four hour access, the vending machine 
has become a vital resource in the retailing chain of many products. There 
are, of course, many types of self-service vending machines which are 
designed to dispense many different types of products. Initially, vending 
machines were not environmentally controlled and were limited to 
dispensing products which were not temperature sensitive. In response to 
the growing demand of consumers to obtain food or beverage products by 
means of a vending machine, a number of vending machines were developed 
which provided refrigeration. See, for example, U.S. Pat. No. 4,920,764 
and the patents discussed therein. 
While such conventional vending machines have been successfully utilized to 
distribute many types of temperature sensitive products, current machines 
are not suitable for distributing humidity sensitive products, such as 
cosmetics or high quality tobacco products, which must be stored and 
maintained at a recommended temperature and humidity to retain the 
freshness and value of the respective product. Thus, to date, consumers 
have been unable to obtain such humidity sensitive products from a 
remotely placed vending machine. 
As is apparent from the above discussion, a need exists for a vending 
machine which is capable of storing humidity sensitive products at a 
recommended temperature and humidity in order to retain the freshness and 
value of the product. A further need exists for a vending machine capable 
of continuously monitoring and adaptively controlling the storage 
environment to maintain desired temperature and humidity settings. Yet 
another need exists for a vending machine humidor which may be located at 
remote locations, to allow a user the convenience of obtaining a desired 
tobacco product by inserting either a credit card or paper currency into 
the vending machine and receiving a selection of one or more desired 
tobacco products. 
SUMMARY OF THE INVENTION 
Generally, according to aspects of the present invention, an 
environmentally controlled vending machine is disclosed which stores and 
maintains humidity sensitive products, such as tobacco or cosmetic 
products, at a recommended temperature and humidity. In accordance with 
another aspect of the invention, the internal environment of the vending 
machine is continuously monitored and adjusted to control the environment 
as necessary to retain the freshness and value of the respective products. 
A number of environmental parameters, such as temperature and humidity, 
are balanced using a closed loop feedback control process in response to 
measured system parameters. 
The disclosed vending machine includes a controller, one or more remote 
sensors, which monitor the environmental conditions within the vending 
machine housing, a fan, a heater strip, a cooling unit, a humidifier, and 
a payment and selection system. In order to best maintain the freshness 
and value of the tobacco products, for example, the vending machine 
preferably stores the products at approximately 70.degree. F. and a 
relative humidity of approximately 70%. 
The controller is preferably embodied as a temperature and humidity 
controller or microprocessor. According to features of the present 
invention, the controller monitors a number of environmental parameters in 
real time and provides feedback control by means of an adaptive control 
loop to achieve desired environmental settings. The controller controls 
heating, humidification, fan circulation and cooling, if required, in 
response to environmental measurements made in real time by the remote 
sensors, such as a thermostat and a humidistat. 
To balance the controlling environmental variables, the controller 
preferably utilizes two controller loops: a temperature control loop and a 
humidity control loop. In one preferred embodiment, each controller loop 
is embodied as a proportional-integral-derivative (PID) loop controller 
object which can preferably be run in a manual, programmed or automatic 
mode as desired. Preferably, the temperature control loop and the humidity 
control loop are run in the automatic mode to maintain the temperature and 
humidity, respectively, to desired values. In this manner, the 
environmental values may be held nearly constant. 
A more complete understanding of the present invention, as well as further 
features and advantages of the invention, will be obtained by reference to 
the detailed description and drawings.

DETAILED DESCRIPTION 
As shown in FIG. 1, an environmentally controlled vending machine 10 
according to the present invention includes an outer housing 15, a power 
supply system 20, a controller 30, one or more remote sensors 35 which 
monitor the environmental conditions within the housing 15, a fan 45, a 
heater strip 50, a cooling unit 55, a humidifier 60, a water deionizer 65, 
a payment and selection system 70, and one or more displays 80. In a 
preferred embodiment, the vending machine 10 may be embodied as a 
conventional spiral type vending machine, such as model number 3039, 
manufactured by FSI, of Des Moines, Iowa, as modified herein to provide 
environmental controls and enhanced payment capabilities. According to 
features of the present invention, the vending machine 10 is designed to 
store and maintain humidity sensitive products, such as tobacco or 
cosmetic products, at a recommended temperature and humidity, and 
continuously monitors and controls the environment to retain the freshness 
and value of the product. 
PRODUCT PAYMENT AND SELECTION 
In a preferred embodiment, shown in FIG. 2, the payment and selection 
system 60 includes a currency exchange unit 210, a currency and selection 
display 220, a credit card validator 230, and a control panel keypad 240. 
The currency exchange unit 210 may be embodied as a bill and/or coin 
mechanism. In the illustrative embodiment, the currency exchange unit 210 
may be embodied as the Coinco Model BA30 bill acceptor, manufactured by 
Coinco Inc. of St. Louis, Mo., which accepts bills and does not make 
change. For a more detailed discussion of a suitable currency exchange 
unit 210, see U.S. Pat. No. 5,310,173, incorporated by reference herein. 
The credit card validator 230 may be embodied as the Veritone (Tranz) Model 
330, manufactured by Veritone Corp. of California, and includes a credit 
card swipe mechanism and a modem (not shown). Once a credit card is 
accepted and validated, a pulse will be generated by the credit card 
validator 230 to the currency exchange unit 210 in the proper amount to 
allow the appropriate product to be dispensed, in a known manner. Once the 
user has paid for the desired product, the user can indicate the selection 
by means of the control panel keypad 240. 
In one implementation, the outer housing 15 includes an LCD display 250, 
which may be utilized to present a user with information on the products 
dispensed through the vending machine 10, as well as the LCD display 220 
for presenting a user with information on payment and selection. 
Alternatively, an LED display may be utilized, or some other illuminated 
or graphical display system. In addition, the outer housing 15 may include 
one or more displays (not shown), such as analog dials, for presenting the 
user with environmental information, such as current temperature and 
humidity readings. 
As shown in FIG. 2, outer housing 15 also preferably incorporates a product 
viewing window 280 and a dispensing tray 290. The power supply system 20 
is preferably a low voltage DC power supply, supplying voltage on the 
order of 115 volts AC, and supplying current on the order of 5 amps. 
ENVIRONMENTAL CONTROLS 
The controller 30 is preferably embodied as a temperature and humidity 
controller or microprocessor, such as the A-Tech-10 microprocessor, 
manufactured by Air Technology Systems, Inc. According to features of the 
present invention, discussed further below in conjunction with FIGS. 3 and 
4, the controller 30 monitors a number of environmental parameters in real 
time and provides feedback control by means of an adaptive control loop to 
achieve desired environmental settings. The controller 30 controls 
heating, humidification, fan circulation and cooling if required, in 
response to environmental measurements made in real time by the sensors 
35, such as a thermostat and a humidistat. Preferably, the controller 30 
will not simultaneously activate heating and cooling functions. The 
controller 30, however, allows humidification in either a heating or a 
cooling mode. Prior to activating either the heating or cooling functions, 
in the manner described below, the controller 30 first enables the fan 
switch for a predefined period. 
It has been found that cigars will best maintain their freshness when 
stored at a temperature of approximately 70.degree. F., and a relative 
humidity of approximately 70% (RH), in accordance with manufacturer 
recommended temperature and humidity conditions. The particular 
environmental settings are selected to maintain the freshness and value of 
the tobacco product, as would be apparent to a person of ordinary skill. 
In order to maintain the vending machine 10 at a desired humidity level, a 
humidifier 60, such as an ultrasonic humidifier, is preferably provided. 
If the humidity readings measured by the humidistat sensor 35 deviate 
significantly from desired levels, the humidifier 60 receives an enable 
signal from the controller 30. The water supply utilized by the humidifier 
60 is preferably deionized water in order to prevent any contaminants from 
being deposited into the vending machine 10. 
The humidifier 60 may be embodied as a Stulz FN 400 H ultrasonic 
humidifier, manufactured by Stulz America of Frederick, Md., which 
utilizes an ultrasonic transducer to produce a mechanical oscillation 
under a cavity, or well, of water. The mechanical oscillation causes the 
water particles to vibrate at high speed (cavitation) to produce high 
energy vapor which is absorbed into the air stream. Upon absorption, heat 
is extracted out of the air by a process known as the latent heat of 
vaporization and results in cooling as well as humidification. It has been 
found that the air parameter requirements for proper absorption is 
approximately 200 ft/min. 
As previously indicated, the ultrasonic humidifier preferably utilizes 
deionized water. Thus, in order to have a reliable supply of deionized 
water, the vending machine 10 preferably incorporates a water deionizer 65 
to remove ionizable solids from the water, using principles of ion 
exchange. Minerals dissolved in water are composed of a positively charged 
metallic part (cation) and a negatively charged non-metallic part (anion). 
Since both anions and cations must be exchanged, and no single resin could 
exchange both, the water deionizer 65 preferably contains two resins. 
Thus, a cation exchange resin is utilized to attract positive ions and an 
anion exchange resin is utilized to attract negative anions, in a known 
manner. As the water passes through the water deionizer 65, an exchange 
occurs when a positive ion contacts a negative exchange site, and when a 
negative ion contacts a positive exchange site. The water purity improves 
with each exchange as more ions are removed. 
In a preferred implementation, the water deionizer 25 is embodied as a 
mixed bed deionizer cartridge filter. The cartridge filter must be 
recharged when the positive and negative ionic exchange resins become 
exhausted. Thus, in a preferred embodiment, the output of the water 
deionizer 25 is monitored by a water quality monitor (not shown) which 
preferably evaluates the water quality based upon water conductivity and 
provides an alarm function. The water quality monitor is preferably 
embodied as a light transformer and an alarm light probe (not shown), such 
as a neon lamp. In operation, the neon lamp will provide an alarm to an 
operator when the measured conductivity value rises above a predefined 
threshold, indicating that the cartridge filter must be replaced. 
In order to maintain the vending machine 10 at a desired temperature, the 
vending machine 10 preferably incorporates a heater strip 50 and a cooling 
unit 55. It is noted that if the vending machine 10 is positioned in an 
environment having a suitable temperature, the heater strip 50 or the 
cooling unit 55 may be unnecessary. Thus, if the temperature readings 
measured by the thermostat sensor 35 deviate significantly from desired 
levels, the controller 30 preferably enables either the heater strip 50 or 
the cooling unit 55, as appropriate. The heater strip 50 is preferably a 
500 watt, 120 volt resistance strip heater which can be installed into the 
circulatory air duct. The cooling unit 55 is preferably a DX type split 
system, comprised of a condenser, a compressor and a cooling coil. The 
condenser is preferably positioned outside of the vending machine 10, with 
the compressor located on the inside of the vending machine 10 and the 
cooling coil positioned in the air recirculation duct. 
To facilitate freshness, the air inside the vending machine 10 is 
preferably circulated at approximately 50-200 ft/min by the circulation 
fan 45. The circulation allows for proper absorption, dissipation and 
necessary product environmental contact to sustain product freshness. 
MONITORING AND FEEDBACK CONTROL PROCESSES 
To balance the controlling environmental variables, the controller 30 
preferably utilizes two controller loops: a temperature control loop 300 
(FIG. 3) and a humidity control loop 400 (FIG. 4). In one preferred 
embodiment, each controller loop is embodied as a 
proportional-integral-derivative (PID) loop controller object which can 
preferably be run in a manual, programmed or automatic mode as desired. 
Manual mode is an open loop controller which requires the operator to 
adjust the system parameters manually. Programmed mode is an open loop 
controller with the controller 30 supplying the system parameter changes. 
Finally, automatic mode is a closed loop controller with feedback based on 
a measured reference parameter. In the illustrative embodiment described 
herein, the temperature control loop 300 and the humidity control loop 400 
are run in the automatic mode to maintain the temperature and humidity, 
respectively, to desired values. In this manner, the environmental values 
may be held nearly constant. 
As previously indicated, the controller 30 preferably utilizes a 
temperature control loop 300, illustrated in FIG. 3, to control the system 
temperature, T, in a closed loop feedback mode in response to temperature 
values measured in real time. Thus, the temperature control loop 300 
receives the current temperature value, T.sub.curr, as measured by the 
thermostat sensor 35, as well as the target temperature value, T.sub.targ. 
The temperature error, Terr, between the current temperature value, 
T.sub.curr, and the target temperature value, T.sub.targ, is calculated 
during step 310 and the system temperature, T, is adjusted during step 320 
to compensate for the calculated temperature error, Terr. The temperature 
can be varied by sending a control signal to the heater strip 50 or 
cooling unit 55, as appropriate. 
As previously indicated, the controller 30 preferably utilizes a humidity 
control loop 400, illustrated in FIG. 4, to control the system humidity, 
H, in a closed loop feedback mode in response to humidity values measured 
in real time. Thus, the humidity control loop 400 receives the current 
humidity value, H.sub.curr, as measured by the humidistat sensor 35, as 
well as the target humidity value, H.sub.targ. The humidity error, Herr, 
between the current humidity value, H.sub.curr, and the target humidity 
value, H.sub.targ, is calculated during step 410 and the system humidity, 
H, is adjusted during step 420 to compensate for the calculated humidity 
error, Herr. The humidity can be varied by sending a control signal to 
humidifier 40. 
It is to be understood that the embodiments and variations shown and 
described herein are illustrative of the principles of this invention only 
and that various modifications may be implemented by those skilled in the 
art without departing from the scope and spirit of the invention.