Headspace autosampler apparatus and method

A headspace autosampling apparatus (92) for generating and delivering gaseous samples to a gas chromatograph or other instrument includes a plurality of vials (98) in a carousel (150). The vials are delivered one at a time from the carousel through a vial delivery mechanism (160) to a heated zone (146) wherein the substances (94, 96) to be analyzed reach equilibrium with the headspace (100, 102) above the samples in the vials, preferably using the full evaporation technique (FET). The vials are generally cylindrical and extend horizontally to facilitate attainment of equilibrium rapidly upon heating. The vials are also preferably rotated about their longitudinal axis prior to sampling so as to achieve a film effect on the interior walls of the vials which further aids in attainment of equilibrium. The apparatus is operative to first pressurize the headspace in the vial with an inert gas, and then to place said headspace in fluid communication with the inlet of a gas chromatograph wherein analytes in the headspace volume are analyzed to determine the composition thereof.

TECHNICAL FIELD 
This invention relates to analysis of materials. Specifically, this 
invention relates to an FET headspace autosampler apparatus for generating 
and delivering gaseous samples to an analytical instrument such as a gas 
chromatograph. 
BACKGROUND ART 
Gas chromatography is an advantageous method for analyzing minute 
quantities of complex mixtures from biological and chemical sources. Gas 
chromatography may be used to determine the constituents in the mixture 
from which the sample is taken. Gas chromatography typically involves 
volatilizing a sample to be analyzed and moving the sample in a stream of 
inert carrier gas. 
The sample and carrier gas are delivered to a packing bed or column in the 
gas chromatograph. The different constituents in the sample move through 
the column at different rates. As a result, they are separated and appear 
one after the other at the output end of the column. At the outlet end the 
separated materials in the sample are identified through their properties 
of thermoconductivity, density differences or by ionization detectors, 
depending on the analyzer type in the gas chromatograph. 
Headspace sampling is a technique that involves testing a gaseous sample 
generated in a closed container above a solid or liquid substance to be 
analyzed. Sampling gaseous material avoids the introduction of 
non-volatile or solid particles or substances which cannot be volatilized 
into the inlet of the gas chromatograph, which is not desirable. 
Headspace sampling in accordance with the present invention optimally 
involves establishing an equilibrium in a sealed vial between a solid or 
liquid phase of a substance to be analyzed and a vapor phase of the 
substance in the headspace volume above the other phase. Equilibrium is 
established by heating or cooling the sample in the vial. A gaseous sample 
is then taken from the headspace and delivered to the analytical 
instrument. 
Headspace sampling in general has advantages because it assures that only 
gaseous material enters the gas chromatograph or other analytical 
instrument. Further, because the sample is vapor, the amount of the sample 
may be much larger than a liquid sample. This increases the sensitivity of 
the analysis. These advantages of headspace sampling make it a useful 
technique in the analysis of polymers, latexes, paints, foods, biological 
materials, environmental samples, pharmaceuticals, fragrances and other 
substances. 
Headspace sampling techniques used in the prior art have certain 
limitations. First, the volatility of a particular substance at a given 
temperature varies depending on the matrix of other materials it is mixed 
with. For example, the same concentration of benzene in water versus 
benzene in gasoline will provide very different concentrations of benzene 
in a headspace at the same temperature. Therefore, in the prior art, it 
has been necessary to prepare calibration samples to simulate the matrix 
of materials in the substance being analyzed. However, this is impossible 
in cases of a solid sample or a substance that is completely unknown. 
A further drawback of prior art headspace sampling techniques is that it 
takes some samples a long time to reach equilibrium between the condensed 
and vapor phases. Achieving equilibrium with prior art equipment often 
requires hours of heating. This is particularly true for viscous or solid 
substances. Some have tried agitation of the sample and vial in an attempt 
to shorten equilibrium times, but this has not proven effective and 
sometimes causes contamination problems. 
Several approaches to headspace sampling are known in the prior art. Each 
of these approaches suffers the drawback that removal of the gaseous 
sample from the headspace disturbs the equilibrium in the headspace. Such 
disturbance of the equilibrium can cause poor repeatability. A further 
problem common to prior art techniques is that a disturbance in 
equilibrium may vary from sample to sample depending on the technique used 
and the properties of the materials being analyzed. 
One approach to headspace sampling used in the prior art is syringe 
sampling. This technique involves removing a sample of gaseous material 
from the headspace volume above a substance to be analyzed, using a 
syringe. The disturbance of the equilibrium in the headspace using this 
technique depends on the amount of headspace in the sample vial compared 
to the volume of the sample removed from the headspace. It also depends on 
the speed of removal of the sample, as removal of the material from the 
headspace will tend to cause more of the substance to enter the vapor 
phase to establish a new equilibrium. 
A further problem with the syringe technique is that when the syringe is 
removed from the vial, some of the vapor will expand and escape from the 
syringe to atmosphere prior to injection of the sample into the inlet port 
which carries the sample into the column of the gas chromatograph, or 
other instrument. Another drawback is that material in the sample may 
begin to condense in the surfaces of the syringe before the sample enters 
the gas chromatograph. As a result, not all the material in the sample may 
be delivered, which causes poor repeatability. 
Another headspace sampling technique used in the prior art is explained 
with reference to FIG. 1. This approach is called fixed volume injection. 
The fixed volume system 10 has a sample vial 12 with a substance 14 
therein. The vial is generally a cylindrical vial which is held in the 
generally upright position during sampling. This is standard with all 
prior art headspace sampling techniques. 
A sampling needle 16 is positioned in the headspace inside the vial above 
the substance. The needle is in fluid communication with a first port 20 
of a six port valve 22. Six port valve 22 alternatively places first 
adjacent ports, shown connected by the solid lines in the drawing, in 
fluid communication when the valve is in a first condition. In a second 
condition of the valve, the alternative adjacent ports shown connected by 
the dashed lines are connected. 
The second and fifth ports of the valve 24 and 26, respectively, are 
connected by a sample loop 27. The third port 28 is connected to the inlet 
of the gas chromatograph. The fourth port 30 is connected to a source of 
inert carrier gas such as helium. The sixth port 32 is connected to a 
valve 34 that is alternatively connected to a source of inert gas or to 
atmosphere. 
In operation, with valve 22 in the condition shown in the drawing, the 
inert gas pressure of port 32 is applied to headspace 18 through port 20. 
In this condition of valve 22, the carrier gas passes through the sample 
loop 27 to the gas chromatograph inlet through ports 30, 26, 24 and 28. 
The conditions of valves 22 and 34 are then changed. In these alternative 
conditions, the headspace sample is directed into the sample loop through 
connection of ports 20 and 24 of the valve. The sample loop 27 also vents 
to atmosphere due to the connection of ports 26 and 32 and the opening of 
valve 34. As a result, sample loop 27 is filled with gaseous material from 
the headspace of the vial. 
The return of valve 22 to the first condition causes the carrier gas to 
wash the sample material in the sample loop into the inlet of the gas 
chromatograph. This is accomplished because the carrier gas is connected 
to port 26 and pushes the material in the sample loop through ports 24 and 
28. 
The operation of the system 10 includes several timed functions including 
the time of heating the sample to attempt to achieve equilibrium, 
pressurization time for the headspace, time of venting the headspace 
vapors through the sample loop and the time of washing the sample loop 
with the carrier gas. The times are preset based on estimates of what may 
be appropriate. In many instances the preset times are totally 
inappropriate for a given sample. All of these timed event functions 
impact the results produced by the gas chromatograph. 
Also problematic is that venting the sample to atmosphere disturbs the 
headspace equilibrium. Another common problem is that the headspace vapor 
passing through the lines and valves of the system begins to condense 
resulting in failure to transmit all the constituents of the sample to the 
analytical instrument. This further adversely affects repeatability and 
cross contamination between samples. 
An alternative type of prior art headspace sampling system 36 is shown in 
FIG. 2. In this system, a vial 38 contains a substance 40 to be analyzed. 
The headspace 42 is pressurized with carrier gas through a sampling needle 
44. At the same time as the headspace is pressurized, the column of the 
connected gas chromatograph 46 is pressurized to the same pressure. 
Carrier gas flow to the vial and to the gas chromatograph is then shut 
off. Thereafter the headspace 42 of the vial is the source of gas 
delivered to the gas chromatograph. 
This type of sampling is suitable for use with gas chromatographs or other 
instruments that have high column pressures. However, many gas 
chromatographs have low column pressures which make this prior art 
approach unsuitable. This is because at low pressures the amount of sample 
delivered into the column of the gas chromatograph is too small to produce 
accurate results. 
In conclusion, prior art sampling devices have inherent problems due to the 
effects of condensation or loss of the constituents of the sample before 
entry into the gas chromatograph. Prior art systems also have the drawback 
that long heating times are required to insure that the headspace reaches 
equilibrium with the other phase of the substance to be analyzed and often 
true equilibrium is not achieved. Prior art systems further have the 
drawback that the fixed machine cycle times for the sampling device are 
not appropriate for the sample, resulting in loss of repeatability. 
Thus there exists a need for a headspace autosampling apparatus that 
provides greater sensitivity and repeatability, reduces cycle times and is 
readily adaptable for use with a variety of substances and types of 
analytical instruments. 
DISCLOSURE OF INVENTION 
It is an object of the present invention to provide a headspace 
autosampling apparatus that provides high sensitivity with greater 
repeatability. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that provides reduced cycle times and faster sample 
turnaround. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that is capable of automatically handling a large 
number of samples. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that is compact and which can be mounted directly 
on a gas chromatograph or other analytical instrument. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that is suitable for use with a wide range of 
sample types. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that is suitable for use with a variety of gas 
chromatography and other analytical units. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that is adapted for use with full evaporation 
technique (FET) headspace analysis. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that employs sample vials that are adapted for 
robotic handling. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that includes a manual sample injection port that 
enables manual injection of samples without loss of sensitivity. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that may be operated under flexible programmable 
control, that simplifies method development, enables optimization of 
headspace conditions and provides greater repeatability. 
It is a further object of the present invention to provide an apparatus 
which performs both purge and trap analysis and headspace analysis 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that provides for manual override of operations in 
the machine cycle. 
It is a further object of the present invention to provide a headspace 
autosampling apparatus that is reliable and has simplified maintenance and 
diagnostic characteristics. 
Further objects of the present invention will be made apparent in the 
following Best Modes for Carrying Out Invention and the appended claims. 
The foregoing objects are accomplished in the preferred embodiment of the 
present invention by headspace autosampling apparatus that includes a 
plurality of vials for holding substances to be analyzed. The vials are 
generally cylindrical and are vertically arranged in stacks with the 
longitudinal axis of the vials extending generally horizontally. 
The vials are fed from a stack into a heated or cooled temperature 
controlled zone inside the apparatus. Ideally the heating or cooling 
results in the substance having both a liquid and vapor phase in the vial. 
Because of the large surface area interface between the liquid sample and 
the headspace volume in the vials due to the generally horizontal vial 
orientation, equilibrium between the liquid substance and the headspace is 
rapidly achieved. In addition, the vial is optimally rotated about its 
longitudinal axis which causes a liquid film of the substance to be 
deposited on the wall of the vial bounding the headspace. This further 
increases the surface area and facilitates achieving equilibrium between 
the vapor phase of the substance in the headspace and the non-vapor phase, 
and reduces the time necessary to achieve equilibrium. 
The apparatus then pressurizes the headspace through a pressurization line. 
The headspace volume is pressurized to a predetermined pressure or flow 
using a flow needle. An inert gas is used to pressurize the headspace. The 
gas temperature is carefully controlled and is maintained at the same 
temperature as the vials so as to not upset the equilibrium in the 
headspace. Thereafter, the pressure in the headspace is relieved to the 
inlet of a gas chromatograph or other instrument, through valving and 
lines that are also carefully temperature controlled. Thereafter, the 
sample is washed into the inlet of the gas chromatograph using a carrier 
gas. The temperature of the carrier gas is also controlled to avoid 
condensation, and its path through the apparatus assures that all of the 
sample is analyzed. 
The headspace autosampling apparatus of the present invention is adapted to 
run samples continuously and to accumulate data on a large number of 
samples without the need for reloading or reprogramming. The preferred 
embodiment of the invention includes several functional features to insure 
accuracy, safety and repeatability of the sampling process. The preferred 
embodiment of the invention is particularly adapted for headspace analysis 
using a technique known as full evaporization technique (FET) which 
enables minimization of matrix effects.

BEST MODES FOR CARRYING OUT INVENTION 
Referring now to the drawings and particularly to FIG. 3, there is shown 
therein a schematic view of the preferred embodiment of a headspace 
autosampling apparatus of the present invention, generally indicated 92. 
The apparatus is adapted for sampling substances 94, 96 located in 
identical vials 98. The vials of the preferred embodiment are generally 
cylindrical and are configured to have a horizontal dimension greater than 
a vertical dimension. Each vial 98 has an interior volume which defines a 
headspace 100, 102 above the substances therein 94, 96, respectively. 
Vials 98 include removable caps 104 at a first axial end of the vials (see 
FIG. 9). A silicone membrane or septum 101 extends across an opening in 
each cap. In the preferred embodiment the septum includes a layer 103 of 
inert material at its interior surface. In the preferred embodiment the 
layer is 10-20 mils of Tetrafluoroethylene (TFE). The membrane is 
preferably 125 mils in thickness. The vial is preferably 2.5 inches long 
and 1.125 inches in outside diameter, with an internal volume of 25 
milliliters. 
A rotating device 106 is adapted for rotating vials 98 about the 
longitudinal axis prior to sampling. As shown in FIGS. 7 and 8 the 
preferred embodiment of the rotating device 106 preferably includes a 
slowly rotating shaft 105. Shaft 105 has a plurality of radially extending 
flexible rubber rods 107 extending therefrom. The rods engage the 
cylindrical side of the vial during each rotation to rotate the adjacent 
vial as shown. Of course in alternative embodiments any type of rotating 
device or other vial moving device suitable for coating the walls of the 
vial with a film of the sample in the manner discussed hereafter may be 
used. 
The vials are enabled to move downward past rotating rods 107 by force of 
gravity. Of course in other embodiments other means of moving the vials 
may be employed including powered vial conveying devices. 
In the apparatus as schematically shown in FIG. 3, a flow needle 108 is in 
fluid communication with a port 110 of a six port valve 112. Flow needle 
108 is mounted in connection a horizontal actuator 114 such as a solenoid 
plunger. When actuator 114 moves inward toward the adjacent vial, the flow 
needle pierces the septum 101 and is placed in fluid communication with 
the headspace 100 and serves as a conducting device for conducting the 
sample out of the headspace. The flow needle 108 is somewhat above center 
of the longitudinal axis of the adjacent vial. This helps to assure that 
the flow needle is disposed vertically above the level of the substance 94 
located on the lower side of the vial. 
A pressurization line 116 is connected to a source 118 of inert gas which 
is preferably helium. Pressurization line 116 includes a regulator 120 and 
has a pressure gauge 122 thereon. Pressurization line 116 includes a first 
flow meter 124 as well as a pressure sensor 126 therein. Pressurization 
line 116 is connected to a port 128 of the six port valve 112. Flowmeter 
124 in the preferred embodiment gives a visual as well as an electrical 
indication of the flow condition of the gas passing therethrough as 
hereinafter explained. 
A carrier gas line 130 is also connected to the source 118 of inert gas. 
The carrier gas line includes a pressure regulator 132 and a pressure 
gauge 134 therein. Carrier gas line 130 includes a second flowmeter 136 
and a pressure release valve 138. Carrier gas line 130 is connected to a 
port 140 of valve 112. Carrier gas line 130 also includes therein a manual 
injection port 142 adjacent to port 140 of the valve. 
Valve 112 includes a port 144 which is in fluid communication with an inlet 
of a gas chromatograph or other analytical instrument. As shown 
schematically in FIG. 3, the vials 98, the flow needle 108, valve 112 and 
the pressurization and carrier lines 116 and 130 are all housed in a 
temperature controlled zone 146 in the apparatus 92. The temperature of 
the temperature controlled zone 146 is maintained by a heat transfer 
device which includes suitable heating and cooling mechanisms such as an 
electrical heater or heat exchanger. It should be understood that all the 
lines, valves, and fluid passages adapted for gas flow in the temperature 
controlled zone are maintained at temperatures consistent with that of the 
headspace of the vials to be sampled. This assures that there is no 
condensation of any material from the sample in the lines that would 
result in loss of sample material and that the equilibrium condition in 
the vial is not upset during the sampling processes. 
With samples that are liquids at room temperature, the temperature 
controlled zone operates at an elevated temperature to achieve equilibrium 
between the liquid sample and the headspace. For substances that are gases 
at room temperature the temperature controlled zone is operated to cool 
and condense a liquid sample portion. 
The apparatus further includes any ejection plunger 148. Ejection plunger 
148 is movable to eject vials from the apparatus after the headspace 
therein is sampled. The ejection plunger is operated in the preferred 
embodiment by a solenoid actuator to eject the vials from the heated zone. 
After a vial is ejected, it may fall outward into a basket or other 
container. When the ejection plunger is retracted, the vials above it fall 
downward in a passage which holds the vials in the temperature controlled 
zone in vertical alignment as shown in FIG. 7. The passage assures that 
the vial previously sampled is in position for ejection while the vial 
positioned immediately above it in the passage is in position for 
sampling. This arrangement further provides that the vial immediately 
above the vial in position for sampling is rotated by rotating device 106. 
Preferably the vial above the vial in direct contact with the rotating 
device is rotated as a result of being in contact with the rotating vial. 
The device of the preferred embodiment heats (or cools) the vials and 
samples the headspace of one vial at a time. However, in other embodiments 
multiple vials may be transported together for heating, rotation or 
sampling. 
The headspace autosampling apparatus of the preferred embodiment of the 
present invention is adapted for sampling various substances in large 
numbers of vials and on a continuous basis. In the preferred embodiment, 
the apparatus includes a carousel 150 (see FIGS. 5 through 6) which serves 
as a holding device. Carousel 150 holds a plurality of vials 98 which are 
vertically arranged in groups or stacks 152. The carousel is adapted for 
holding 10 stacks of four vials each in the preferred embodiment. When 
positioned in the carousel, the vials are all arranged so that their caps 
104 and the rubber septums therein are outwardly directed. 
The carousel 150 is rotationally movable by an indexing device such as a 
stepper motor or other type of mechanism which is operable to rotate the 
carousel. The indexing device is operable to rotate the carousel into a 
desired position for feeding the vials 98 into the delivery device for 
delivering the vials into the temperature controlled zone wherein they are 
heated (or cooled depending on the state of the sample at room 
temperature), rotated and sampled. The carousel 150 is mounted above a 
housing 154 (see FIG. 4) which includes a temperature controlled enclosure 
156. Enclosure 156 encloses temperature controlled zone 146. Enclosure 156 
includes a lateral opening 158 through which vials ejected by ejection 
plunger 148 pass out of the device. The ejection plunger is sized similar 
to opening 158 and is generally extended during most of the machine cycle, 
except when it retracts to engage a vial for ejection. As a result the 
ejection plunger minimizes heat transfer through the opening to help 
maintain a constant temperature in the temperature controlled zone. 
The housing 154 includes a vial delivery mechanism 160 thereon. Mechanism 
160 includes a sliding member 162 which is positioned above the 
temperature controlled zone. The sliding member 162 includes an aperture 
164 therein. The aperture is sized for accepting a single vial 98 so that 
the wall bounding the vial at the top is aligned with the top of the 
sliding member. 
The sliding member 162 is movable by a feed mechanism, which in the 
preferred embodiment includes a solenoid, between a first aperture 
position shown in FIG. 4 and a second aperture position which is shown in 
phantom. In the first aperture position, the aperture 164 is enabled to 
receive a vial from one of the stacks 152 in the carousel. In a second 
position of the aperture, the aperture is positioned over the passage into 
which the vials pass into the temperature controlled zone for eventual 
sampling. 
The sliding member 162 has a wall extending adjacent its underside so that 
a vial in the aperture moves in captured relation with the sliding member 
until the sliding member reaches the second position. In the second 
position the vial falls into the passage and enters the temperature 
controlled zone. In the second position the vial is in vertically stacked 
relation with other vials in the passage which are being heated (or 
cooled) and are awaiting sampling. The delivery mechanism 160 not only 
operates to deliver the vials one at a time for sampling, but also serves 
as a cover for the passage into the temperature controlled zone. As a 
result, the mechanism helps to maintain the temperature controlled zone at 
a stable temperature. 
A sensor (not separately shown) is also positioned in the housing 154 
adjacent the aperture in the first position. The sensor, which is 
preferably a photo sensor, is adapted for sensing when no vials remain in 
a group. In this condition the control logic of the apparatus causes the 
carousel to rotate until the next group is over the aperture. A programmed 
controller controls the machine operates to continue rotation of the 
carousel until all the groups have been tried and it is determined that no 
additional vials are available for sampling, at which point the apparatus 
is shut off after the last vial in the passage is sampled. 
It should be noted that carousel 150 includes a base plate 166. The base 
plate includes an opening 168 which corresponds to the first position of 
aperture 164 of the sliding member. The base plate 166 also operates to 
support vials 98 in the groups 152. As the carousel indexes, the bottom 
vials in the groups move rotationally about their longitudinal axis. This 
rotation also causes the vials above to rotate. This rotation during 
indexing aids in producing a film effect, which causes a film of the 
substance to be analyzed to be deposited on the interior walls of the 
vials as they rotate. The film effect facilitates the attainment of 
equilibrium in the headspace of the vial when the vial reaches the 
temperature controlled zone. 
The headspace autosampling apparatus of the present invention is operated 
under the control of a programmable controller. The controller preferably 
includes several built in programs stored in memory as well as the ability 
to be programmed with custom programs through an interface port. The 
control programs control the times for loading of the vial from the 
carousel 150 into the passage for heating or cooling. The programs also 
control the movement of the flow needle to pierce the septum of the vial 
and the condition of the six port valve. The programs also typically 
control the ejection plunger which operates to eject a vial after 
sampling. 
The preferred form of the invention also includes other features in the 
control programs to assure safe operation and to facilitate the interface 
of the apparatus with a gas chromatograph or other analytical instrument. 
These features include temperature sensors in the temperature controlled 
zone 146 to insure that the unit will not operate to produce samples if 
the temperature in the temperature controlled zone is not within certain 
limits. In the event the temperature should exceed a programmed limit, the 
controller of the unit executes a built-in alarm program routine. This 
routine operates to eject all sample vials from the temperature controlled 
zone, and then shuts off the device. This avoids possible dangerous 
conditions from overheating. The apparatus also includes an interface with 
a gas chromatograph or other instrument which can be used to insure that 
the instrument is operating properly and is ready to receive samples 
before the autosampling unit commences operation. 
Another novel aspect of the invention is a feature which allows relief of 
the pressure on the column of the gas chromatograph by opening a pressure 
release valve 138 and closing it again prior to delivering a sample. Such 
relief of the column pressure is desirable where the column pressure is 
high and may resist the infiltration of sample material, or in situations 
where high pressure may adversely impact sensitivity. The pressure release 
valve can also be used to relieve pressure in the vials after sampling as 
a safety precaution, in which case its outlet may be ducted to a suitable 
trap. Further control functions are associated with the use of a trap 
shown in phantom as 170 on the line leading to the inlet of the gas 
chromatograph which may be used for trapping and/or later delivery of 
constituents in the samples. Further features of the control programs 
provide for counting and identifying samples and for shutting off the gas 
chromatograph when all the samples have been sampled. The control programs 
are also operative to detect fault conditions and to shut off the 
apparatus when fault conditions are detected. 
The preferred form of the invention provides flexibility by enabling 
programmed control of all the functions, as well as hard wired control 
through externally mounted electrical terminal strips. This enables 
simplification of method development and optimization of headspace 
conditions. The preferred form of the apparatus of the present invention 
also includes manual override controls for the functions performed by the 
unit. 
In operation, the headspace autosampling apparatus of the present invention 
operates to deliver gaseous samples to an inlet of a gas chromatograph or 
other analytical instrument in the ways hereinafter described. The 
apparatus is first allowed to heat up or cool down to the desired 
operating temperature of the temperature controlled zone. Once the unit is 
at operating temperature, it is loaded with a plurality of vials 98 
holding any calibration samples and the substances to be analyzed, and the 
unit is ready to begin operation. 
The carousel 150 and the vial delivery mechanism 160 is operated to begin 
delivering vials 98 into the temperature controlled zone 148 by 
transferring them into the passage. In the passage the vials 98 are in 
vertically aligned relation. Once in the temperature controlled zone the 
heating or cooling therein quickly causes headspace volumes in the vials 
to reach equilibrium with a liquid sample portion (or solid sample portion 
when the sample goes directly from a solid to a vapor phase). The 
achievement of equilibrium is facilitated not only by the rotation of the 
vials which is caused by the movement of the carousel, but is greatly 
enhanced by rotation of the vials in the passage by rotating device 106. 
The rotation of the vial causes this film of the substance to be present 
on virtually the entire inner surface of the sample vial bounding the 
headspace. This film greatly increases the surface area from which the 
sample material evaporates into the headspace. The film is replenished 
with each rotation. As a result equilibrium is rapidly achieved. 
Once a vial in the passage is adjacent with flow needle 108, the actuator 
114 moves the flow needle forward to pierce the septum bounding the 
headspace of the vial. The six port valve 112 is initially in position to 
deliver pressurization flow of inert gas into the headspace 100 of the 
vial being sampled. This flow is continued until the pressurization flow 
observed by the operator at flow meter 124, or preferably as electrically 
sensed, reaches zero. 
Once the vial is fully pressurized to the desired pressure, six port valve 
112 changes its condition so that the headspace 100 is in fluid connection 
with the inlet of the gas chromatograph through port 114. Thereafter, 
valve 112 returns to its first condition as shown in FIG. 3 so that the 
carrier gas is delivered through the flow conduit in the six port valve 
that was previously connected to the headspace. As a result, the sample, 
including the material in the flow conduit in the six port valve, is 
washed into the inlet of the gas chromatograph. 
Once the sample is taken, the flow needle withdraws from the vial and the 
ejection plunger 148 retracts from the position shown in FIG. 3. This 
enables the vial 98 at the sample position to fall downward. The ejection 
plunger then moves forward to eject the vial from the machine through 
opening 158. At the same time, the vial immediately above in the passage 
is ready for sampling. The process is repeated as the delivery mechanism 
continues to deliver additional vials into the passage for sampling. 
An advantage of the preferred embodiment of the present invention is that 
in the gas injection mode, if the gas flow at flow meter 124 does not 
reach zero, it is known that there is a leak and the results will be 
unreliable. Likewise, if the flow at flow meter 136 should fall to zero 
during the time that it is operable to wash the sample into the inlet of 
the gas chromatograph, it is known that there is a problem. These 
conditions may be signaled by use of an alarm or may be recorded by the 
controller and correlated with the particular sample vial, so that the 
results are questioned. 
In certain environments where the column pressure of a gas chromatograph is 
high, the operating cycle of the apparatus of the present invention may 
include the opening of pressure release valve 138 prior to delivery of a 
sample to the gas chromatograph. The opening of the pressure release valve 
138 will relieve the pressure on the column and will enable the sample to 
flow into the inlet of the gas chromatograph at lower pressures. The flow 
meter 136 also enables setting the flow so that the sample is delivered 
for analysis at the desired speed. 
An alternative mode of operation for the preferred embodiment of the 
headspace autosampling apparatus is to control the pressurization of the 
headspace in accordance with pressure sensed at sensor 126. The 
pressurization of the vials to a uniform pressure rather than to a zero 
flow condition has the advantage of reducing the affects of the volatility 
of the materials in the sample matrix. Such approach also avoids 
conditions of too short pressurization time which may cause inadequate 
volume samples, or too long pressurization time which may result in 
diffusion of the vapor out of the headspace. 
The method of control of the apparatus by pressurization of the headspace 
to a uniform pressure also enables identification of fault conditions. 
This is because a problem is immediately detected if the desired pressure 
is not achieved. As a result, it is known that any sample produced from 
the headspace of the corresponding vial is not meaningful data and should 
be disregarded. 
The invention is also enabled to conduct multiple headspace extraction 
analysis by modifying the operating cycle of the apparatus. In multiple 
headspace analysis the headspace volume of the same sample is sampled by 
repeated withdrawal of material. By extrapolating from the decreasing 
concentration of the substance of interest, the original concentration of 
the material may be estimated. The repeated withdrawal of material from 
the headspace volume of a sample is accomplished by valve 172 and trap 174 
shown in FIG. 3, operating the apparatus under control of a control 
program for this procedure in the processor. 
The invention is preferably operated in accordance with the analytical 
method known as the full evaporation technique (FET). Using FET headspace 
analysis matrix effects in samples are reduced. FET involves reducing the 
sample size and correspondingly controlling sample temperatures so that 
analytes are transferred completely from a condensed matrix to a confined 
vapor phase. This effectively eliminates the effect of the partition 
coefficient for the matrix. The technique is described in detail in the 
paper entitled "Matrix Independent Headspace Gas Chromatographic 
Analysis--The Full Evaporation Technique". Analytica Chimica Alta, 276 
(1993) 235-245, Elsevier Science Publishers B.V., Amsterdam, authored by 
Dr. Michael Markelov and John P. Guzowski, Jr. 
The preferred embodiment of the present invention is particularly well 
adapted for operation using FET autosampling. The use of the horizontally 
oriented sample vials as well as the film effect achieved by rotation of 
the vials about their longitudinal axis prior to sampling is particularly 
advantageous in achieving near complete vaporization of the substances of 
interest. Further, the careful temperature control of the pressurization 
gas and the sample assure reliable delivery of the sample to an analytical 
instrument. 
An alternative embodiment comprising a combined purge and trap and a 
headspace sampling unit 182 is shown in FIG. 10. The unit 182 is shown 
with both a vial 184 and a purge vessel 186. The vial 184 is the same type 
of vial described above and is shown with an enclosed substance. The 
substance equilibrates into a liquid and/or solid phase 188 shown at the 
bottom of the vial, and a vapor phase 190 shown in the headspace of the 
vial. 
The purge vessel comprises a glass tube shown with both an inlet 192 and an 
outlet 194 connected to tubing. The vessel further comprises a glass frit 
196 disposed medially in the interior of the vessel between the inlet and 
the outlet. The glass frit includes a plurality of openings sized so that 
gas can pass through them but liquid is retained on the frit. A sample 198 
is shown thus retained. 
The unit 182 further comprises two six way valves 200 and 202, and a three 
way solenoid valve 204. All of these valves are automatically actuated 
between their two positions and act to route the gas flow through the 
unit. An inert gas is supplied to the unit at inlet 206. The inert gas 
flows to both a pressurization gas train 208 and a carrier gas train 210. 
These gas trains both contains instrumentation which can both indicate and 
control the flow and pressure of the gas flowing through each train. 
The unit 182 also includes a trap 212, which is connected across ports 214 
and 220 of valve 200. This trap comprises a tube through which gas can 
flow. The tube encloses a porous adsorbent suitable to adsorb the VOC 
being tested, and desorb the same VOC when the adsorbent is heated. 
The unit 182 fluidly communicates with a gas chromatograph 236 via port 234 
of valve 202. The valve 202 also communicates with a needle 238. The 
needle is automatically moved into and out of the vial 184 by actuating 
rod 240. When retracted from the vial the needle can act as a vent for gas 
to flow to the atmosphere. The ports 226 and 228 of valve 202 are plugged. 
The gas flowing from the pressurization train is routed to port 242 of the 
three way solenoid valve 204. When the valve is in the dashed position the 
gas is routed to the trap 212. When the valve is positioned so that the 
solid marked flow path is open the gas flows to he purge vessel 186. 
In operation the unit is initially positioned in a standby mode. In this 
standby mode the dashed flow paths of valves 200, 202 and 204 are open, 
and the needle is retracted from the vial. The gas from the pressurization 
train 208 to port 218 of valve 200 via port 246 of valve 204. The gas 
sweeps across the trap 212 and flows out to the atmosphere via ports 214 
and 216 of valve 200 port 230 and 232 of valve 202 and the needle 238. In 
standby mode the carrier gas flows from the carrier gas train to the gas 
chromatograph 236 via port 212 and 222 of valve 200 and ports 224 and 234 
of valve 202. 
When a purge and trap operation is to be performed, a sample is introduces 
onto the frit 196 of the purge vessel 186. To put the unit into purge mode 
the valve 204 is positioned so that the solid flow path is open. Both of 
the valves 200 and 202 remain in the position with the dashed flow paths 
open. The needle 238 remains retracted from the vial 184. In the purge 
mode gas flows from the pressurization train 208 to the purge vessel via 
ports 242 and 244 of valve 204. The gas passes through the many passages 
of the frit 196 and bubbles up through the sample 198. A gas flowrate 
through the frit is maintained so that the gas does not jet or form large 
expanding bubbles. Instead a large number of relatively small bubbles are 
formed by the gas, which flow separately from the frit through the liquid 
sample 198 to the liquid gas interface of the sample and the headspace of 
the purge vessel. The plurality of bubbles in aggregate comprise a great 
liquid gas surface area. This large surface area acts to increase the mass 
transfer rate of the volatile molecular components of the sample 198 from 
the liquid phase to the vapor phase. The agitation of the liquid sample by 
the gas bubbles also acts to increase this mass transfer to the gas phase. 
The volatilized components are then convectively transferred out of the 
purge vessel and to the trap 212 via ports 218 and 220 of valve 200. The 
volatilized components of the sample are adsorbed onto the media contained 
within the trap as the gas flow passes through the trap. The gas thus 
stripped of the volatilized components of the sample flows to the 
atmosphere via ports 214 and 216 of valve 200, ports 230 and 232 of valve 
202 and the needle 238. 
The purge mode is operated on a timed basis. The purge mode flowpath is 
maintained for a preset period of time which is sufficient to fully 
volatilize the desired components from the sample contained in the purge 
vessel. This preset time is contained in the memory of the programmable 
controller. The preset times can be programmed for purposes of purging 
different types of samples. 
After the purge mode time period is counted down by the controller the 
controller causes the unit to either enter a dry purge mode or a desorbing 
mode. The dry purge mode is used to rid the trap of excess water which was 
convectively transferred from the purge vessel 186 and was accumulated in 
the trap 212. In this dry purge mode the three way solenoid valve 204 is 
returned to the position it occupied in the standby mode where the port 
communicated along the dashed flow path. The gas is thus routed from the 
pressurization gas train 208 to the trap via ports 242 and 246 of valve 
204, and ports 218 and 220 of valve 200. The gas sweeps the trap of 
accumulated water and carries it out of the unit via ports 214 and 216 of 
valve 200, ports 230 and 232 of valve 202 and the needle 238. The sweeping 
gas flow across the trap is maintained for a desired preset time period. 
The sweeping gas flow does not affect the adsorbed chemicals on the 
adsorbent within the trap. 
If the dry purge mode is not required or desired the unit immediately 
enters into the desorb mode after the termination of the purge mode. 
Alternatively if the dry purge mode is utilized, the unit switches to the 
desorb mode after the dry purge mode. In the desorb mode the unit occludes 
the trap from the rest of the unit and then heats the trap. The trap is 
occluded by first moving the needle 238 to a closed environment. This 
closed environment can take the form of a vial such as vial 184 or a 
special block composed of an elastic medium that blocks the exit of the 
gas from the needle. The occlusion operation can be monitored and 
controlled by the flow measurement device included in the pressurization 
gas train 208. When the flow of gas through the pressurization train is 
stopped, the flow measurement device communicates to the controller that 
the trap is occluded. Once the signal is received by the controller, the 
controller initiates the heating of the trap. The occlusion operation can 
alternatively be monitored by pressure transmitter 248 which sends a 
signal to the controller corresponding to the pressure in any of the lines 
downstream of the pressurization gas train. The controller compares the 
pressure to that of the pressure signal received from the pressure 
transmitter in the pressurization gas train. When the two pressures are 
equal the controller initiates the heating of the trap. 
In the heating operation the trap temperature is raise to a desorption 
temperature appropriate to desorb the adsorbed chemicals from the 
adsorbent which is used in the trap. These temperatures are often 
specified in published purge and trap procedures. The desorbed chemicals 
reenter the gas stream. Because of the stagnant gas surrounding the trap 
the desorbed chemicals remain in the vicinity of the trap. The heating 
operation time is also a preset value which is resident in memory and 
counted down by the controller. At the end of the heating operation the 
unit switches from a desorb mode to an inject mode. 
In the inject mode the valve 200 is modulated so that the flow paths shown 
in solid are open. The pressurization gas remains stagnant in the inject 
mode as the needle remains in a closed environment. During the previous 
standby, purge, dry purge, and desorb modes the gas flowing from the 
carrier gas train 210 has been flowing to the gas chromatograph via ports 
212 and 222 of valve 200, and ports 224 and 234 of valve 202. Because of 
the port flow changes in valve 200 the gas flowing from the carrier gas 
train is routed through the trap 212 via ports 212 and 214. The carrier 
gas sweeps the desorbed gasses from the trap and convectively transfers it 
to the gas chromatograph via ports 220 and 222 of valve 200, and ports 224 
and 234 of valve 202. 
The purge and trap operation can alternatively be performed automatically 
on a plurality of samples using a plurality of purge vessels. All of the 
purge vessels comprise a tube with a medially disposed frit. The gas inlet 
of all of the purge vessels are operatively fluidly connected with port 
244 of valve 204. The inlets can be connected via a muliplexing valve 
which directs the flow of gas from port 244 of valve 214 to a first purge 
vessel. The outlets of all of these purge vessels are fluidly connected to 
point 250 on the tubing. Thus connected the purge and trap operation is 
conducted on a first purge vessel. Once the purge and trap operation is 
completed the multiplexing valve automatically is switched to connect port 
244 of valve 204 to an adjacent or second purge vessel. The purge and trap 
operation is then automatically performed by the unit on this second purge 
vessel. When a particular purge vessel is connected to the port 244 of 
valve 204 the other purge vessels are isolated from the gas flows within 
the unit, therefore the enclosed samples in these purge vessels are not 
contaminated by any other samples. Thus any number of sample containing 
purge vessels can be automatically analyzed. 
In addition to the purge and trap operation the combined purge and trap and 
headspace analysis unit shown in FIGS. 10 and 11 can be used to perform: 
direct headspace analysis of sample vials using a time controlled 
injection; direct headspace analysis of sample vials using a volume 
control injection; headspace analysis of vials using a trapping 
preconcentrator; and high sensitivity FET on sample vials. 
The direct headspace analysis of samples can be performed by the unit 182 
in the configuration shown in FIG. 10. The purge vessel is emptied or 
plugged is a sample is contained therein. Initially valves 200, 202 and 
204 are positioned so that the dashed flow paths are open. Initially the 
needle is retracted from the vial, and the vial with contained sample is 
heated in the previously described heating zone. Gas from the 
pressurization gas train 208 flows through the retracted needle to the 
atmosphere sweeping any contaminants from the tubing. The gas from the 
carrier train 210 similarly sweeps the column within the gas 
chromatograph. 
After a time is allowed for the lines to be swept and the sample to be 
heated long enough so that the enclosed sample has reached an equilibrated 
state, the vial headspace is pressurized. The needle 238 is first plunged 
into the headspace 90 of the vial 184 by the actuating rod 240. The gas 
flowing from the pressurization train 208 is then injected into the 
headspace of the vial on a time controlled or volume controlled basis. In 
a time controlled injection the gas is allowed to flow into the headspace 
for a preset time. The headspace pressure steadily increases throughout 
the injection period. The flow meter in the pressurization gas train can 
be used to measure the gas flowrate entering the vial in the injection 
period. These discrete flowrates can then be used by the controller to 
determine and record the total volume of gas injected into the vial. At 
the end of this injection time period the valve 202 is switched by the 
controller so that the solid flow paths are open. When this occurs the 
pressurized headspace acts as the gas source for the column of he gas 
chromatograph 236. The gas flows from the headspace through the needle to 
the gas chromatograph via ports 232 and 234 of valve 202. The gas from the 
carrier train is stopped by the occluded port 226. The gas is allowed to 
vent from the headspace to the gas chromatograph for a preset period of 
time. At the end of this time the valve 202 is switched back to the 
position it occupied during the standby mode, and the needle is retracted 
from the vial headspace. The vial can then be ejected and the procedure 
performed on the next vial. 
The vial can alternatively be injected with gas at a preset pressure. The 
gas is injected until the pressure transmitter contained within the 
pressurization gas train reaches a preset value. The gas pressure in the 
headspace continually increases until the time when the controller senses 
the preset pressure has been reached and actuates the valve 202 to move to 
the position in which the solid gas flowpaths are open. At this time the 
gas from the headspace is vented to the column of the gas chromatograph. 
The unit 182 has an alternative configuration shown in FIG. 11. In FIG. 11 
the components of the unit are substantially similar to those in FIG. 10, 
and the similar components are shown primed to highlight them for purposes 
of comparison of the two configurations of the unit. In the unit 182' the 
purge vessel 186' is isolated from the unit by having both its inlet 192' 
and its outlet 194' plugged or occluded. The tubing configuration of unit 
182' differs from that of unit 182 in that port 218' of valve 200' is 
connected to port 230' of valve 202, port 216' of valve 200' is connected 
to port 242' of valve 204' and the pressurization gas train 208' is 
connected to port 246' of valve 204'. Unit 182' also included a vent valve 
which is simply an automatic on/off valve 252. The vent valve allows port 
244' of valve 204' to selectively communicate with the atmosphere. The 
vent valve 252' is normally open. 
The unit 182' can be used to perform headspace analysis of samples using 
the trap 212' in a preconcentration mode. In this procedure the unit is 
initially in a standby mode in which the valves 200, 202 and 204 are 
positions so that the dashed flow paths are open. In this standby mode the 
needle 238' is retracted from the vial 184' and gas from the 
pressurization train 208' sweeps the gas lines and the trap 212' through 
the retracted needle, while gas from the carrier gas train 210' sweeps the 
column of the gas chromatograph 236'. While the unit is in standby mode 
the vial 184' is heated and rotated as described above in the same way as 
the vials are treated in the standby modes associated with unit 182. 
When the sample in the vial 184' has reached equilibrium, the unit 182' 
enters a headspace pressure mode. The controller causes actuating rod 240' 
to plunge the needle 238 into the vial 184' and the headspace of the vial 
is pressurized from gas from the pressurization train 208'. The 
pressurization of the vial can be done on a time controlled basis or a 
time controlled basis as described above. After the headspace has been 
pressurized the unit 182 enters the purge mode. 
In the purge mode the controller switched the position of valve 204 so that 
the trap is vented to atmosphere via ports 214' and 216' of valve 200', 
ports 242' and 244' of valve 204' and the vent valve 252. When valve 204' 
is in this position the headspace of vial 184 is allowed to depressurize 
to atmosphere through the trap 212'. The volatilized sample components are 
adsorbed onto the adsorbent contained within the trap 212' and the 
remaining gasses flow to the atmosphere. This purge mode is continued for 
a preset time by the controller, and at the end of the time period the 
trap is occluded and heated in a desorption mode. The controller can 
alternatively put the unit 182' into a dry purge mode in which dry gas 
from the pressurization train sweeps the trap to remove any accumulated 
water. 
At the start of the desorption mode the controller switches the valve 204 
back to the initial position in which port 242' communicates with port 
244'. The controller also closes the vent valve 252. The gas flow from the 
pressurization train is thus halted and the trap is surrounded by a 
stagnant gas. The controller then causes the heating of the trap. The trap 
212' is heated for a preset time sufficient enough to revolatilize the 
adsorbed gasses of the sample. After this time period is run the 
controller puts the unit 182 into a injection mode. 
In the injection mode the valve 200 is positioned so that the solid flow 
paths are open, the valve 242' and valve 202' remain in their previous 
positions. The gas from the pressurization train 210' now sweeps the trap 
of the desorbed gasses by flowing to the trap via ports 212' and 214 of 
valve 200'. The gas then convectively transfers the desorbed gasses to the 
gas chromatograph 236' via ports 220' and 222' of valve 200' and ports 
224' and 234' of valve 202'. The sampling thus completed the vial is 
ejected and the analysis cycle on the next vial is initiated. 
The alternative configuration of the unit 182' can also be used for simple 
headspace analysis in the above described manner without utilizing the 
trap to preconcentrate the volatilized components of the sample. Both of 
the units 182 and 182' can be used to perform FET analysis, in which the 
sample size is reduced and headspace analysis is performed on the fully 
volatilized components of the sample. 
Although the preferred embodiment of the headspace autosampling apparatus 
of the present invention employs a carousel for holding sample vials, 
other embodiments of the invention may employ other types of holding 
devices. For example, the invention may be operated with a magazine type 
tower for holding a single stack of sample vials. Other embodiments may 
use other types of bins or feeding mechanisms. 
A further advantage of the present invention is that it is very compact and 
may be mounted directly on a gas chromatograph or other analytical 
instrument. This avoids the need for long transfer lines and the possible 
inaccuracies which may result due to condensation of the sample material 
in such lines. 
The preferred embodiment of the invention is also equipped with a manual 
injection port. This port is particularly advantageous in that it is 
mounted on the six port valve, and manually injected samples travel by the 
same route as those taken automatically. As a result, the present 
invention may be operated by direct syringe sampling techniques without 
disconnecting the apparatus from the gas chromatograph, and the 
sensitivity is maintained for both sample types. 
The headspace autosampling apparatus of the present invention achieves 
several fundamental advantages over the prior art as a result of sampling 
the headspace in cylindrical vials that are oriented so that their 
longitudinal axes extend in a generally horizontal direction. In this 
orientation, the surface area of evaporation for the substance to be 
analyzed is substantially increased from normal vials which are sampled 
with a longitudinal axis in a generally upright condition. The increase in 
surface area significantly decreases the time required to reach 
equilibrium between the substance and the headspace. 
A further advantage of the orientation and configuration of the vials of 
the preferred embodiment of the headspace sampling apparatus of the 
present invention is that the thickness of the liquid layer of a substance 
to be analyzed is reduced. This reduction in thickness results in a 
dramatic increase in diffusion rate of a component to the liquid/gas 
interface, because diffusion time is a square function of the thickness of 
the substance layer. 
The horizontal position of the vials also enables their rotation while in 
the temperature controlled zone. As a result of rotation, liquid samples 
form a thin film on the interior walls of the vials. This greater surface 
area and decreased thickness of the film further increase the rate of 
diffusion of the sample into the headspace and reduce the time for the 
substance to achieve equilibrium with the headspace. The film is also 
replenished with each rotation further speeding achievement of 
equilibrium. Optimally the vials are rotated a plurality of times prior to 
sampling. Heat transfer to the sample is also facilitated. Applicant has 
found that cylindrical vials in which the length is 1.6 times the radius 
are well suited for this purpose. However, other embodiments may use vials 
having other configurations. 
A further advantage of the rotation of the vessels is that it acts to 
increase the heat up of the liquid sample. The thin film of liquid that 
clings to the glass vial wall absorbs heat through the wall. The lower 
boiling components of the liquid volatilize with this heat increase. With 
the continued rotation of the vial the adhering volatilized components are 
reintroduced back into the bulk liquid portion of the sample. This reflux 
acts to increase the separation of the volatile components from the rest 
of the sample. 
The horizontal orientation of the sample vials also enables the preferred 
embodiment of the present invention to be much more compact and to hold a 
large number of samples in a machine that occupies very little space. 
A further significant advantage of the present invention is that the vials 
include a novel twist off cap and septum construction. Prior art headspace 
sample vials have all used a cover that is crimped over the vertically 
oriented opening. Crimping is undesirable because it makes reopening and 
reclosing vials difficult. This can be a problem where it is desired to 
add materials to the vial after initial closure. 
A further fundamental advantage of the vials that are a part of the present 
invention is that they are well suited for handling by robots. This 
reduces labor costs and facilitates sample preparation of materials that 
pose risks in manual handling. 
The preferred form of the vials of the invention achieve the desired 
results by using temperature resistant caps comprised of phenolic plastic 
and a silicone rubber septum for sealing between the vial and the cap. The 
septum is generally TFE coated on its interior surface, but other coatings 
such as metallic coatings may be used depending on the type of sample. 
Thus, the new headspace autosampling apparatus of the present invention 
achieves the above stated objectives, eliminates difficulties encountered 
in the use of prior devices and systems, solves problems and attains the 
desirable results described herein. 
In the foregoing description certain terms have been used for brevity, 
clarity and understanding, however no unnecessary limitations are to be 
implied therefrom because such terms are for descriptive purposes and are 
intended to broadly construed. Moreover, the descriptions and 
illustrations are by way of examples and the invention is not limited to 
the details shown and described. 
Further in the following claims any feature claimed as a means for 
performing a function shall be construed to encompass any means capable of 
performing the function and shall not be construed as limited to the means 
used for performing this function in the foregoing description or mere 
equivalents thereof. 
Having described the features, discoveries and principles of the invention, 
the manner in which it is constructed and operated, and the advantages an 
useful results attained; the new and useful structures, devices, elements, 
arrangements, parts, combinations, systems, equipment, operations and 
relationships are set forth in the appended claims.