United States Patent [19]
Gieskieng
[11] Patent Number:
[45] Date of Patent:
4,459,103
JuI. 10, 1984
16 Claims, 4 Drawing Figures
4,223,549 9/1980 Kitzinger 374/142 X
4,330,808 5/1982 Sawada et aI. 73/28
4,358,948 1111982 Plessers 374/26
Primary Examiner-Daniel M. Yasich
An analyzer is provided for use in determining the volatile
matter content of coal and coke. The analyzer automatically
adjusts a position of a crucible containing a
coal or coke sample relative to a furnace depending
upon the temperature of the crucible. The crucible is
supported and the temperature of the crucible and sample
is sensed by means of a thermocouple arranged as a
sling for contacting the crucible. The sensed temperature
is compared with a predetermined and desired
temperature. A comparison difference triggers a vertical
movement of the crucible and sample, within the
temperature profile of the furnace, using a servomotor
until the crucible is positioned such that the sensed
temperature and desired temperature correspond.
[54] AUTOMATIC VOLATILE MATTER
CONTENT ANALYZER
[75] Inventor: David H. Gieskieng, Arvada, Colo.
[73] Assignee: Hazen Research, Inc., Golden, Colo.
[21] AppI. No.: 356,858
[22] Filed: Mar. 10, 1982
[51] Int. C1.3 C21D 11/00; F27B 9/40
[52] U.S. Ct•........................................ 432/43; 266/87;
373/136; 374/180; 432/45
[58] Field of Search 374/157, 139, 180, 26;
136/229,234,232,230; 164/154,449; 266/87;
432/43,45
[56] References Cited
U.S. PATENT DOCUMENTS
2,864,878 12/1958 Da1glish 136/229
3,444,740 5/1969 Davis 136/230 X
3,463,005 8/1969 Hance 374/157 X
3,598,386 8/1971 Murphy 266/87 X
3,653,262 4/1972 Ehrenfried et aI. 374/142
[57] ABSTRACT
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the present invention;
FIG. 2 is an enlarged, fragmentary, side elevational
view of the thermocouple sling supporting a crucible;
FIG. 3 is a bottom plan view of the thermocouple
sling without the crucible; and
FIG. 4 is a detailed schematic of the controlling/timing
circuit of the present invention.
2
provides a sensed temperature signal of itself and consequently
is indicative of the temperature of the crucible
it contacts and the sample contained therein. The movement
of the crucible in the vertical direction can be
5 made to be a function of the temperature sensed by the
thermocouple sling. The servomotor is controlled by a
controlling/timing circuit using the temperature signal.
More particularly, the thermocouple sling of the
present invention includes two dissimilar metals, in this
10 case Chromel and Alumel, to generate a sensed temperature
millivoltage signal relating to the temperature of
the thermocouple sling, crucible, and the sample. The
sensed temperature signal is inputted to the recorder
device which in addition to recording, outputs a voltage
somewhat proportional to the sensed temperature. The
temperature-related voltage provided by a recorder
retransmitting slidewire is compared with one or more
predetermined adjustable voltages chosen to correspond
to desired temperature levels or set-points. Any
difference between the sensed temperature and the target
temperatures is translated into movement of the
crucible to a different height within the furnace. Specifically,
if the thermocouple sling sensed temperature is
less than the target or set-point temperature, the servomotor
is activated to lower the crucible relative to the
furnace to expose it to higher heat. Conversely, if the
sensed temperature is greater than the predetermined
desired temperature, the servomotor is activated to
raise the crucible relative to the furnace. In such a manner,
the temperature to which the coal sample is subjected
can be controlled at one or more temperature
set-points for predetermined time periods to assure a
proper determination of volatile matter content.
In view of the foregoing, it is readily seen that a
number of advantages of the present invention are
achieved. An apparatus is provided for automatically
sensing and controlling the temperature of a coal sample
to determine its volatile matter content. More significant,
a thermocouple sling provides two important
functions. The thermocouple sling not only senses the
temperature to which the coal sample is being subjected
but also acts to support the crucible and coal sample
held by the crucible, providing a contact measurement
of the crucible temperature and hence the temperature
of the contained sample. In addition, this analyzer automatically
moves the vertical position of the crucible and
coal sample as a function of temperature, unlike previous
devices which rely solely on predetermined positions
in a furnace. Use of the present invention permits
rapid and accurate testing of volatile matter content of
a coal sample, since the reproducibility of test results is
maximized because of the increased precision in temperature
control and heating rates.
Additional advantages of the present invention will
become readily apparent from the following discussion
when taken in conjunction with the accompanying
drawings.
4,459,103
1
DISCLOSURE OF THE INVENTION
AUTOMATIC VOLATILE MATTER CONTENT
ANALYZER
In accordance with the present invention, an apparatus
is provided for use in analyzing the volatile matter 60
content of coal and coke. The apparatus includes a
loosely covered crucible for holding a small sample of
coal or coke. A thermocouple-sling combination is releasably
joined to the crucible for supporting the crucible.
The thermocouple sling is fastened to a motorized 65
suspension and wired to a recorder device. The crucible
is vertically movable within a tubular furnace by using
the servomotor. The thermocouple sling combination
An empirical distillation method analysis of the volatile
matter content of coal and coke samples is intended 15
to provide a measure of the volume of gaseous product,
exclusive of the free moisture content, which is produced
from such samples under a set ofstandard heating
conditions. The volatile matter content is a parameter
used in classifying coals and is significant in determining 20
and designing compatible combustion hardware for use
in the coal combustion process.
In the ASTM Standard Test Method for "Volatile
Matter In The Analysis Sample of Coal and Coke", D
3175-73 (1973), a method is disclosed for determining 25
the volatile matter content of coal or coke. The method
involves weighing the coal sample, heating the coal
sample to determine the weight loss after the heating,
determining the moisture content of the coal sample
using the standard found in ASTM D 3173, and then 30
subtracting the moisture content from the weight loss.
For the heating step, an operator determines, beforehand,
the approximate desired position of the coal sample
in a vertical tubular furnace by using a portable
thermocouple. The thermocouple is not connected to 35
the crucible but is, typically, a separate device inserted
by the operator into the furnace for use in determining
the temperature profile therein. In another known embodiment,
a thermocouple device is connected to the
furnace itself for providing an indication ofthe tempera- 40
ture thereof at that specific point in the furnace, usually
the bottom, so that this may be used to adjust approximately
the temperature of at least the hottest point of
the temperature profile.
An automatic volatile analyzer of coke and coal is 45
described in the EDP catalog with respect to the PreiserlMineco
volatile programmer. The analyzer described
includes holding timers for use in determining
when to move a crucible containing a coal sample to
different positions in a furnace. Different descent rates 50
of the crucible into the furnace area are also provided in
this automatic analyzer. This analyzer moves the crucible
as a function of time to preselected positions in the
furnace. Although these preselected positions in the
furnace are expected to be at desired temperatures, this 55
is often not the case.
FIELD OF THE INVENTION
The present invention relates to an apparatus for use
in determining the volatile matter content of coal and
coke and, in particular, is directed to a temperature
sensing and controlling arrangement, which also functions
to support a crucible in which the coal or coke is
placed for analysis.
BACKGROUND ART
4,459,103
3
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
In accordance with the present invention, an apparatus
for use in empirically detemining the volatile matter 5
content of a coal or coke sample is provided. With
reference to FIGS. 1, 2, and 3, the apparatus includes a
crucible 10 having a slightly loose cover 12 for holding
or containing the sample of coal or coke. The crucible
10 is releasably supported by a thermocouple mecha- 10
nism in the form of a thermocouple sling 14. The thermocouple
sling 14 includes two dissimilar metal elements
16, 18. In the preferred embodiment, the two
metal elements are Alumel and Chromel. As can best be
seen in FIGS. 2 and 3, the two elements 16, 18 are 15
joined together to form thermocouple junctions 20, 22
using "Quiktip" connectors. The two thermocouple
junctions 20, 22 contact or touch the crucible 10 and are
used to sense the temperature of the crucible 10. It is
also appreciated that since the thermocouple junctions 20
20, 22 contact the crucible 10 containing the sample, the
thermocouple junctions 20, 22 also provide an indication
of the temperature of the sample. The sensed temperature
signals from the two thermocouple junctions
20, 22 are averaged to provide a single sensed tempera- 25
ture signal. Portions of the two elements 16, 18 are
formed in the shape of a semi-circle and connected
together at the thermocouple junctions 20, 22 to provide
an opening for receiving the crucible 10. The elements
16, 18 then extend upwardly to be electrically 30
connected to a recorder device 24 through a flexible
electrically insulated conductor 26 weighted on each
end by the masses of weights 28, 30. The recorder device
24 provides a visual indication· of the temperature
sensed by the thermocouple sling 14 as well as making 35
a pen recording on a strip chart.
From the recorder device 24, an electrical representation
of the sensed temperature signal is obtained from its
retransmitting slide wire and is applied to a controlling/
timing circuit 31 of FIG. 1. The controlling/timing 40
circuit 31 controls the energization or activation of a
servomotor circuit 33 according to preplanned setpoints
and periods of time. The servomotor circuit 33 is
operatively connected to a pulley 32 about which the
insulated conductor 26 is wrap hung. The insulated 45
flexible conductor 26 carries the sensed temperature
millivoltage signal to the recorder device 24. The servomotor
circuit 33 is used to turn or rotate the pulley 32
clockwise or counterclockwise for raising or lowering
thermocouple sling 14, crucible 10 and the sample con- 50
tained therein in a substantially vertical direction with
respect to a tubular furnace 36. The temperature of the
tubular furnace is initially regulated by a powerstat 38
and left set.
The furnace 36 has a temperature profile with the 55
hottest part located at he bottom thereof. Preferably,
one portion or level of the furnace 36 has a temperature
of 600' C. and another lower level or portion of the
furnace 36 has a temperature of 950' C. It has been
found that an accurate determination of volatile matter 60
content of coal and coke can be made when a sample
thereof is subjected to heat at these two different temperatures
for preselected time periods.
Referring now also to FIG. 4, as well as FIG. 1, a
more detailed representation of an embodiment of the 65
present invention is shown. The controlling/timing
circuit 31 of FIG. 1 includes reference circuit 40. The
reference circuit 40 includes a first variable resistor 42
4
which includes a sliding contactor 44 positioned at a
predetermined position along the resistor 42 so that a
first reference temperature signal voltage corresponding
to a first predetermined and desired temperature is
picked off and applied to a comparator circuit 46. The
reference circuit 40 also includes a relay 48 for switching
between the first reference temperature signal and a
second predetermined reference signal, which is provided
by means of a second variable resistor 50 having
a sliding contactor 52. The reference circuit also includes
a relay 54 for removing the excitation of variable
resistor 50 at a later preselected time. In the preferred
embodiment, the first reference temperature signal corresponds
to a temperature of 600' C. and the second
reference temperature signal corresponds to a temperature
of 950' C.
The comparator circuit 46 also receives a retransmitted
temperature related signal from the recorder device
24, which is basically responsive to the temperature
detected by the thermocouple sling 14. The comparator
circuit 46 outputs a temperature difference signal primarily
representing the polarity of the difference between
the retransmitted temperature related signal and
the selected one of the two reference signals. This temperature
difference signal is modified by a chopper
circuit 56. The chopper circuit 56 is a vibrating switch
energized at the line frequency. The switch chopped
pulses of the temperature difference signals are thereby
synchronized with the sinusoidal variation of the line
power. The phase relationship ofthese pulses to the line
power then depends upon the positive or negative difference
between the sensed temperature signal and the
reference signal.
The pulsed output from the chopper circuit 56 is
applied to an amplifier circuit 58 including voltage amplifiers
60, 62 for the necessary voltage amplification of
the pulsed output. A power amplifier 64 of the amplifier
circuit 58 is for generating sufficient power to drive
servomotor winding 66 with pulses corresponding to
the positive or negative portion of the sinusoidal voltage
provided by transformer 68. However, the power
amplified pulses are transmitted through an interrupt
circuit 70. The interrupt circuit 70 includes a motor
driven cam switch 72, and a shorting relay 74, the
contacts of which are connected across the contacts of
the motor cam switch 72 to stop the interruptor action
of the interrupt circuit 70 when required. Whenever a
cam 75 of cam switch 72 has rotated such that a notch
76 formed in the cam 74 receives a finger 78, a contact
80 provides an electrical connection between the transformer
68 and a selector switch 82 to provide power to
the power amplifier 64 and servomotor circuit 33, when
the selector switch 82 is in an "auto" position. The
"auto" position provides an automatic mode of moving
the crucible 10, the movement depending upon the
temperature of the crucible 10 and the magnitudes of
the reference signals as well as the controlling/timing
circuit 28. The interrupt circuit 70 provides short, infrequent
pulse driving of the servomotor of the servomotor
circuit 30 so that the temperature of the crucible 10
and thermocouple sling 14 has sufficient time to equilibrate
or settle prior to the next pulsed movement, so
that the next movement, if required, will be in the
proper direction.
The direction of movement of the pulley 32, referencing
FIG. 4, hence the direction of vertical movement of
the crucible 10 and thermocouple sling 14 depends upon
the polarity of the pulses outputted by the chopper
4,459,103
5 6
circuit 56, which determines the phase relationship of is then moved upwardly while still under manual conthe
amplified pulses reaching the windings 66 of the trol. The movement of the thermocouple sling 14 is
servomotor. When the pulses have a negative polarity halted when it is approximately 1.5 inches above the
indicating that the reference signal is greater in magni- furnace 36. Next, the thermocouple sling 14 receives the
tude than the magnitude of the sensed temperature sig- 5 crucible 10 containing a weighted sample of coal or
nal, the phase of the voltage across the windings 66 is coke. The selector switch 82 is then set to its "autosuch
that the pulley 32 is driven in a counterclockwise matic" mode with the switch contacts positioned as
direction by the servomotor, lowering the crucible 10 illustrated in FIG..4. At this time, the comparator cirand
thermocouple sling 14 into hotter areas of the fur- cuit 46 compares the sensed temperature signal indicanace.
Conversely, when the pulses have a positive sense 10 tive of a temperature of approximately 100· C., from the
indicating that the referenc.e signal is less·in magnitude recorder device 24, with the first reference signal correthan
the magnitude of the sensed temperature signal, the sponding to 600· C. The first timer 86 is then enabled
phase of the voltage applied· across the windings 66 is with pushbutton 88 and begins to count down from its
such that the pulley 32 is driven in a clockwise sense by preset time period. In the preferred embodiment, the
the servomotor, raising the crucible 10 and thermo- 15 first timer 86 is set for about six (6) minutes.
couple sling 14 into cooler areas of the furnace, or at the Initially during this six minute time period, since the
end out of the furnace. thermocouple sling 14 and crucible 10 are above the
As illustrated in FIG. 4, the energization of the coils furnace 36 and now at a temperature of about 100· C.,
associated with the relays 48 and 74 is controlled by the the first reference signal is greater in magnitude than the
timer circuit 84, assuming the selector switch 82 is in the 20 sensed temperature signal. As a result, downward mo-
"auto" mode. The timer circuit 84 includes a first timer tion phased pulses are generated by the chopper circuit
86 which is enabled by pushbutton 88, and begins to 56 and amplified for driving the servomotor through
count down from a predetermined stored count with the cam switch 72, and the servomotor of the servomorelay
48 connected to the first set-point reference of tor circuit 30 is driven in a downward direction for a
sliding contactor 44 and the interruptor bypass relay 74 25 1/10 second interval during each revolution of the cam
in its open position. The first timer 86 is coupled to a . 75. In a preferred em1:Jodiment, the cam 75 rotates one
second timer 90, a time delay relay 92 and a coil 94. complete revolution each twelve (12) seconds. The
When the predetermined time set in the first timer 86 is interruptor contact 80 provides a relatively slow decompleted,
the output from the first timer energizes the scent of the crucible 10 into the furnace 36 because of
coil 94. The energization ofthis coil 94 changes the state 30 the intermittent energization of the servomotor. This
of the relay 48 so that the first reference is disconnected permits orderly venting of evaporating moisture and
and the second reference signal is applied to the com- other low boiling fractions. If these were allowed to
parator circuit 46. Further, when the first timer 86 times erupt by a faster temperature rise, some sample material
out, the second timer 9Qis enabled to count down for its would be blown out of the crucible 10 thereby destroypredetermined
time interval. At the· beginning of the 35 ing the test.
second timer 90 predetermined time interval, time delay The sensed temperature of the thermocouple sling 14
relay 92 energizes relay coil 96 for six (6) seconds. corresponds to the first reference temperature of 600·
While the coil 96 is energized, the relay 74 is closed and C. after about five minutes of intermittent descent into
the interrupting action of the cam switch 72 is bypassed, the furnace 36, because at this time thermocouple juncso
that the servomotor drives continuously as there is a 40 tions 20, 22 are positioned in the furnace 36 at its 600· C.
difference signal from the comparator circuit 46, caused level. This temperature is maintained for the remaining
by relay 48 shifting to the set-point of sliding contactor one minute of the six minute time period. This tempera-
52, which is higher than the previous set-point of sliding ture is maintained by comparing the sensed temperature
contactor 44. This permits the servomotor to quickly signal with the first reference signal. Any difference in
drive the crucible 10 to the temperature area· corre- 45 magnitude between the sensed tempe~ature signal al)d
sponding to the second set-point, which requires about the first reference signal is used to vertically adjust the
6 seconds, after which time delay relay 92 times out, position of the crucible 10. The direction of vertical
opening relay 74, thereby re-enabling cam switch 72. movement of the crucible 10 and thermocouple sling 14
The second timer 90 continues to operate through the depends upon the polarity of the pulses outputted from
remainder of the desired high temperature period and 50 the chopper circuit 56.
when it times out coil 98 is energized. The energization At the completion of this first six minute time period,
of coil 98 switches open the state of relay 54 so that a the second timer 90 and time delay relay 92 are enabled.
zero reference signal is applied to the comparator cir- The second timer 90 has a time period of about six
cuit 46. In this state of the relay 54, as well as relay 48, minutes associated therewith. With the activation of the
and the contact interruptor 80 bypassed, the crucible 10 55 second timer 90, the coil 96 is also energized which
and sample are quickly moved in a vertically upward closes relay 74 for the six second duration of the time
direction out of the furnace to where the servomotor delay relay 92. In addition, coil 94 is energized. so that
runs into a mechanical stop. relay 48 changes state and the first reference signal is
To further understand the present inventions, a typi- n::moved and the second reference signal, correspondcal
test process is now described. Initially, power is 60 ing to 950· C., is applied to the circuit 46. With the
applied to the furnace 36, the selector switch 82 is closure of relay 74 and the changing to the second referplaced
in "manual" mode, and the thermocouple sling ence signal, downward motion phased chopper pulses
14 is moved using the selector switch 82and switch 83 are continuously applied to the servomotor windings 66
to the bottom of the furnace 36, without the crucible 10 so that the crucible 10 and sample are relatively quickly
held thereby, where the furnace 36 is the hottest. When 65 moved downwardly into the furnace 36. This rapid
the thermocouple sling 14 detects a temperature of movement positions the crucible 10 very quickly in that
about IS· C. above the second predetermined reference portion of the furnace 36 which is at a temperature of
temperature (950·+IS· C.), the thermocouple sling 14 about 950·. Upon completion of this six second time
4,459,103
8
couple sling. In this regard, the thermocouple sling not
only provides a signal relating to the temperature of the
crucible and the sample contained therein but also supports
the crucible for vertical movement with respect to
5 a furnace. In addition, the control circuitry of the analyzer
permits a proper determination of the volatile matter
content to be made by regulating the rate of temperature
changes and the amount of time that the sample is
subjected to predetermined temperatures. Consequently,
accuracy of the volatile matter content determination
is maximized and reproducibility of results is
enhanced. Furthermore, multiple samples can be analyzed
simultaneously to increase the analytical capacity
and also minimize the amount of hardware needed.
Although the present invention has been described
with reference to a plurality of embodiments, it is
readily appreciated that variations and modifications
can be effected within the spirit and scope of this invention.
What is claimed is:
1. An apparatus for use in analyzing the volatile content
of a sample comprising:
a furnace;
first means for holding the sample;
thermocouple means contacting said first means for
suspendedly supporting said first means and also
providing a temperature signal relating to the temperature
of said first means; and
second means responsive to said temperature signal
for adjusting the position of said first means with
respect to the furnace.
2. An apparatus for use in analyzing the volatile content
of a sample comprising:
first means for holding the sample relative to a heated
container;
thermocouple means for suspendedly supporting said
first means moving therewith and providing a temperature
signal relating to the temperature of said
thermocouple means; and
second means in operative association with said thermocouple
means for moving said thermocouple
means and said first means, the movement of said
first means and said thermocouple means depending
upon the temperature of said thermocouple
means.
3. An apparatus, as claimed in claims 1 or 2, wherein:
said second means includes means for generating a
first reference signal corresponding to a first temperature.
4. An apparatus, as claimed in claims 1 or 2, wherein:
said thermocouple means includes two dissimilar
metal elements joined together at least at one junction.
5. An apparatus, as claimed in claims 1 or 2, wherein
said second means includes:
means for generating a first reference signal corresponding
to a first temperature; and
means responsive to said generating means for comparing
the first reference signal with the temperature
signal provided by said thermocouple means.
6. An apparatus, as claimed in claims 1 or 2, wherein:
said second means includes interrupt means for use in
intermittently moving said first means.
7. An apparatus for use in both supporting a container
and the material contained therein relative to a heating
means and providing an indication ofthe temperature of
said container and the material contained therein comprising;
7
period, the coil 96 is deenergized and the relay 74 opens.
Any further vertical adjustment of the crucible 10 is
then once again moderated by the cam switch 72 as well
as controlled by any pulses outputted by the chopper
circuit 56.
The second timer 90 like the first timer 86, also normally
has a six (6) minute time period associated therewith.
During this period, which begins immediately
after the completion of the time period associated with
the first timer 86, any necessary vertical adjustment of 10
the crucible 10 is automatically made to maintain the
crucible 10 at a temperature of950° C., the initial adjustment
hastened by bypassing for six seconds the cam
switch 72 using time delay relay 92. At the completion
of this six minute period, the relay 54 opens and the 15
relay 74 is once again closed. When relay 54 is open, the
reference temperature signal to the comparator circuit
46 corresponds to a very low temperature and the
sensed temperature is much greater than that, causing
upward motion chopper pulses. Also, since relay 74 is 20
once again closed, upward phased power pulses are
continuously applied to the servomotor circuit 30
through the relay 74 while bypassing the cam switch 72
in order that the crucible 10 may be quickly raised from
the furnace 36. The crucible 10 can then be removed 25
from the thermocouple sling 14 for further cooling and
subsequent weighing in order to determine the volatile
matter content of the sample contained in the crucible
10. The predetermined time periods set in the first and
second timers and noted in the foregoing discussion 30
have been empirically determined and the use thereof is
intended to maximize the accuracy of the volatile matter
content analysis.
In another preferred arrangement, the recorder device
24, the reference circuit 40, the comparator circuit 35
46, the chopper circuit 56, and the amplifier circuit 58
are time shared with at least two furnaces, servomotor
circuits, thermocouple slings, and crucibles. In such an
embodiment the interrupt circuit 70 is modified to include
a cam switch having two notches, wherein the 40
notches are separated by 1800 to provide a pulse every
six (6) seconds. Another cam with a 50% down profile
and switch are added to effect the transfer ofthe foregoing
control equipment from one furnace to another in a
synchronized manner. Consequently, during! revolu- 45
tion of the cam switch or every six seconds, vertical
adjustment of one of the two crucibles is controlled,
while during the second half of the cam revolution the
other of the two crucibles can be controlled using the
1/10 second pulses which occur once during each six 50
second period. This arrangement results in the chart of
the recorder device 24 being a sequential composite of
the two crucible temperatures while doubling the analytical
capacity of the apparatus.
Although the embodiments discussed herein have 55
been described or illustrated with reference to particular
hardware, such as relays, vacuum tubes and transformers,
it is readily appreciated that other appropriate
electrical hardware can be utilized. With respect to the
recorder device 24, such a device is commercially avail- 60
able from Leeds and Northrup under the name
"SPEED-O-MAX H".
Based on the above disclosure, it is readily discerned
that a number of worthwhile benefits are achieved in
the present invention. A volatile matter content analy- 65
zer is provided for automatically adjusting the position
of a crucible and a sample relative to a furnace by continually
using the temperature sensed by a thermo4,459,103
20
15
40
10
porting said container means and for providing a
temperature signal relating to the temperature of
the sample; and
driving means in operative association with said thermocouple
sling for moving said container means
and said thermocouple sling relative to said furnace
means depending upon the temperature signal.
14. An apparatus, as claimed in claim 13, and further
comprising:
first means for generating a reference signal;
second means responsive to said first means for comparing
the reference signal to the temperature signal
and for providing an output signal; and
third means communicating with said second means
for intermittently applying the output signal from
said second means to said driving means.
15. An apparatus, as claimed in claim 14, wherein:
said thermocouple sling includes at least one thermocouple
junction where two dissimilar metal elements
are joined together, said thermocouple junction
contacting said container means.
16. An apparatus for use in analyzing the volatile
content of a sample comprising:
furnace means supported on a surface;
container means for holding the sample;
a thermocouple sling in contacting association with
said container means for use in suspendedly supporting
said container means, moving therewith
and providing a temperature signal relating to the
temperature of the sample;
driving means in operative association with said thermocouple
sling for moving said container means
and said thermocouple sling relative to said furnace
means depending upon the temperature signal;
first means for generating a reference signal;
second means responsive to said first means for comparing
the reference signal to the temperature signal
and for providing an output signal; and
third means communicating with said second means
for intermittently applying the output signal from
said second means to said driving means to move
said container means and said thermocouple sling;
said thermocouple sling includes at least one thermocouple
junction where two dissimilar metal elements
are joined together, said thermocouple junction
adapted to contact said container; and
said thermocouple sling includes first and second
metal elements arranged to form an opening between
portions of said metal elements, said opening
adapted to receive the crucible.
* * * * *
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9
a thermocouple sling in releasable contacting association
with the container having material contained
therein, said thermocouple sling suspendedly supporting
said container and the material contained
therein relative to a surface but spaced therefrom, 5
and said thermocouple sling generating a temperature
signal relating to the temperature of said container
and the material contained therein, whereby
means responsive to said temperature signal adjusts
the thermocouple sling relative to the container. 10
8. An apparatus, as claimed in claim 7, wherein:
said thermocouple sling includes at least one thermocouple
junction where two dissimilar metals are
joined together, said thermocouple junction
adapted to contact said container.
9. An apparatus, as claimed in claim 7, wherein:
said thermocouple sling includes first and second
metals arranged to form an opening between portions
of said metals, said opening adapted to receive
said container.
10. In a system for determining the volatile matter
content of a coal or coke sample including a furnace, a
crucible for holding the sample, and means for use in
moving the crucible and sample, a device comprising:
a thermocouple sling in releasable operative associa- 25
tion with said crucible for contacting and suspendedly
supporting said crucible, said thermocouple
sling being movable by said moving means with
respect to said furnace together with said crucible
and said sample, and said thermocouple sling gen- 30
erating a temperature signal relating to the temperature
of said crucible, said sample, and said thermocouple
sling for controlling movement of said moving
means in response to said temperature signal.
11. A device, as claimed in claim 10, wherein:
said thermocouple sling includes at least one thermocouple
junction where two dissimilar metal elements
are joined together, said thermocouple junction
contacting said crucible.
12. A device, as claimed in claim 10, wherein:
said thermocouple sling includes first and second
metal elements arranged to form an opening between
portions of said metal elements, said opening
adapted to receive said crucible.
13. An apparatus for use in analyzing the volatile 45
content of a sample adapted to be positioned relative to
a furnace, comprising:
furnace means supported on a surface;
container means for holding the sample;
a thermocouple sling in contacting association with 50
said container means for use in suspendedly sup-
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