U.S. Patent Dec. 21, 2021 Sheet 18 of 25 US 11,204,288 B2

200
268 270 bee
274
272 a
274 =
268
250.12
2266 270
268
274
0
250.13
268
272 3 266
: }p——_ 950.14
)Snnnnneet
[250.15
A 220

Figure. 18


U.S. Patent Dec. 21, 2021 Sheet 12 of 25 US 11,204,288 B2

200

250.11

\

Pp 236.1

See ee!

Figure. 12


U.S. Patent Dec. 21, 2021 Sheet 22 of 25 US 11,204,288 B2

284.4

pa 284

Figure. 22


U.S. Patent Dec. 21, 2021 Sheet 3 of 25 US 11,204,288 B2

am 282

250.1
250.2
. 250.8
278 .
278 236
278
280
280

om 250.4

ep 250.5

Figure. 3


US 11,204,288 B2

15

rather are used to distinguish one element from another. The
modifier “about” used in connection with a quantity is
inclusive of the stated value and has the meaning dictated by
the context (e.g., it includes the degree of error associated
with measurement of the particular quantity). The conjunc-
tion “or” is used to link objects of a list or alternatives and
is not disjunctive; rather the elements can be used separately
or can be combined together under appropriate circum-
stances.

What is claimed is:

1. A triple point immersion cell article for determining a
triple point of a non-metallic analyte, the triple point immer-
sion cell article comprising:

a first cryochamber comprising a first cryo-zone;

a second cryochamber comprising a second cryo-zone,

the second cryochamber being:

nested and disposed in the first cryochamber; and

thermally isolated from an exterior environment of the
triple point immersion cell article by the first cryo-
chamber;

a third cryochamber comprising a third cryo-zone, the

third cryochamber being:

nested and disposed in the second cryochamber;

thermally isolated from the exterior environment by the
first cryochamber and the second cryochamber; and

thermally isolated from the first cryochamber by the
second cryochamber; and

a fourth cryochamber comprising a fourth cryo-zone, the 3

fourth cryochamber being:
nested and disposed in the third cryochamber;
thermally isolated from the exterior environment by the
first cryochamber, the second cryochamber, and the
third cryochamber; and
thermally isolated from the second cryochamber by the
third cryochamber; and
a triple-point pressure vessel comprising a fifth cryo-
zone, the triple-point pressure vessel being:
nested and disposed in the fourth cryochamber;
thermally isolated from the exterior environment by
the first cryochamber, the second cryochamber,
the third cryochamber, and the fourth cryocham-
ber; and
thermally isolated from the third cryochamber by the
fourth cryochamber; and
a thermowell disposed in the triple-point pressure vessel,
the triple-point pressure vessel being directly acces-
sible from the exterior environment via thermowell.

2. The triple point immersion cell article of claim 1,
further comprising a first cryocooler in thermal communi-
cation with the first cryochamber.

3. The triple point immersion cell article of claim 2,
wherein the first cryocooler actively cools the first cryo-
chamber to produce the first cryo-zone.

4. The triple point immersion cell article of claim 2,
wherein the first cryocooler comprises a Stirling cycle
cryocooler.

5. The triple point immersion cell article of claim 1,
further comprising a second cryocooler in thermal commu-
nication with the second cryochamber.

6. The triple point immersion cell article of claim 5,
wherein the second cryocooler actively cools the second
cryochamber to produce the second cryo-zone.

7. The triple point immersion cell article of claim 5,
wherein the second cryocooler comprises a Stirling cycle
cryocooler.

2

16

8. The triple point immersion cell article of claim 1,
wherein the first cryo-zone and the second cryo-zone are
subjected to closed-cycle refrigeration in an absence of a
liquid cryogen.

9. The triple point immersion cell article of claim 1,
wherein the fourth cryo-zone is an adiabatic zone with
respect to a triple point transition temperature of non-
metallic analyte.

10. The triple point immersion cell article of claim 1,
wherein the first cryochamber, the second cryochamber, the
third cryochamber, and the fourth cryochamber are revers-
ibly demountable and re-mountable from one another.

11. The triple point immersion cell article of claim 1,
wherein the triple-point pressure vessel accommodates a
fixed point of the non-metallic analyte from 75 K to 175 K.

12. The triple point immersion cell article of claim 1,
wherein the fourth cryo-zone provides a stable and repro-
ducible melt plateau for the non-metallic analyte.

13. The triple point immersion cell article of claim 1,
wherein the non-metallic analyte comprises a rare gas con-
densate.

14. The triple point immersion cell article of claim 1,
wherein the triple-point pressure vessel and triple-point cell
interior volume receive a long-stem thermometer or capsule-
type thermometer for calibration at the triple point of the
non-metallic analyte.

15. The triple point immersion cell article of claim 1,
wherein a pressure of the first cryochamber, the second
cryochamber, the third cryochamber, and the fourth cryo-
chamber is high-vacuum.

16. The triple point immersion cell article of claim 1,
wherein the first cryo-zone, the second cryo-zone, the third
cryo-zone, and the fourth cryo-zone are subjected to active
control.

17. The triple point immersion cell article of claim 1,
further comprising a thermowell with a length that is from
10 cm to 100 cm to receive a long-stem thermometer,

wherein the thermowell is in thermal communication with

the first cryo-zone, the second cryo-zone, the third
ceryo-zone, and the fourth cryo-zone and in mechanical
communication with the first cryochamber, the second
cryochamber, the third cryochamber, the fourth cryo-
chamber, the triple-point pressure vessel, the trip
point cell interior volume, and the thermowell recei
ing helium as a heat exchange gas at a pressure from 1
millibar (mbar) to 1.3 bar.

18. The triple point immersion cell article of claim 1,
further comprising a vacuum chamber housing disposed
around the first cryochamber.

19. A process for determining a triple point of a non-
metallic analyte with the triple point immersion cell article
of claim 1, the process comprising:

evacuating a vacuum chamber in which the first cryo-

chamber is disposed;
cooling the first cryo-zone, the second cryo-zone, the third
cryo-zone, and the fourth cryo-zone with a cryocooler;

flowing the non-metallic analyte into the triple point cell
interior volume to partially condense the non-metallic
analyte;

inserting an immersion cooler in the thermowell to com-

plete condensation of the non-metallic analyte;
initiating freezing of the non-metallic analyte;

removing the immersion cooler;

introducing a calibrated standard platinum resistance ther-

mometer into the thermowell;

flowing helium heat-exchange gas in the thermowell:



U.S. Patent Dec. 21, 2021 Sheet 19 of 25 US 11,204,288 B2

200

pe 226

——

Figure. 19


U.S. Patent Dec. 21, 2021 Sheet 25 of 25 US 11,204,288 B2

#00
B02 —~t evacuating vacuum chamber 236 l
¥.
s00—~ operating cryocoolers 230 and 232 to pre-cool interior zones
mu go that the interior zone achieve their base temperature
306-—~ opening valve 242 to flow non-metallic analyte 210 into triple
“ne point cell interior volume 282 and partially condease
308 —~ inserting an immersion cooler in thermowel! 284 to complete
ww condensation and initiate freezing of non-metallic analyte 210

310~f removing the immersion cooler and introducing a calibrated long-stem check SPRT \«--

¥
312} flowing helium heatrexchange gas 238 in thermowell 284 |
¥
adjusting set point. temperatures for the eryochambers
toa selected value for the non-metallic analyte

B14

¥
316-~} waiting for equilibration of temperatures |
¥

pulse heating of the triple point cell pressure vessel in energy
318-~Lincremenis of approximately 2 % melted fraction of the known
enthalpy of fusion for the mass of condensed non-metallic analyte 210

320 ~Lacquiring data for SPRTs as pulse melting continues and the frozen analyte starts to melt. |

¥
322 ~Ladjusting the set poini of the fourth eryozone to the adiabatic condition |
¥.
continuing pulse melting with long recovery intervals and
approximately 10 % melted fraction (MF) pulse duration.

3824-4

¥
326 ~f suspending, near MF= 50 %, pulse heating |

328 removing check SPRT

330 ~Leyeling other SPRTs under test into and out of thermowell 284 in tuco_|

382 —~hreturning to the original check SPRT upon completion of the calibration cycle |

334 resuming pulse melting

resetting, when non-metallic analyte 210 is completely melted,
the third cryozone and fourth cryozone to be off and removing

386-4

338 —~reinserting immersion cooler and refreezing non-metallic analyte 210 } aeneecnnnneent

Figure. 25


U.S. Patent Dec. 21, 2021 Sheet 21 of 25 US 11,204,288 B2

200
268 fF 270 pw ere
284.4
274
274
ia 3
an : 268
274 = DAG on
270 : 270
S466 Phect
274 by _ fle
He 270, 274
268 | 288
270
272
sa
266
272 £. 86
o 266
268

284.2 264

262

Figure. 21


US 11,204,288 B2

17

adjusting a set point temperature of each of the first
ceryochamber, the second cryochamber, the third cryo-
chamber, and the fourth cryochamber to a selected
value for the non-metallic analyte;

pulse heating of the triple point cell pressure vessel in
energy increments;

adjusting a set point of the fourth cryo-zone to an adia-
batic condition;

suspending pulse heating;

removing the calibrated standard platinum resistance ther-
mometer;

disposing a test standard platinum resistance thermometer
into thermowell;

removing the test standard platinum resistance thermom-
eter from the thermowell;

re-disposing the calibrated standard platinum resistance
thermometer in the thermowell;

resuming pulse melting:

completely melting the non-metallic analyte;

reinserting the immersion cooler into the thermowell; and

refreezing the non-metallic analyte to determine the triple
point of the non-metallic analyte.

ee eR RF

0

0

18


U.S. Patent Dec. 21, 2021 Sheet 16 of 25 US 11,204,288 B2

200
268 270 Te
272

- 274

asqta fon, ‘ae 268
266 i
268 ONES ono
274

oo 250.382

a oe
250.13

ap 216

“Sena

Figure. 16


U.S. Patent Dec. 21, 2021 Sheet 8 of 25 US 11,204,288 B2

200

250.1

Figure. 8


US 11,204,288 B2

11

a metal-gasketed fitting when not in use. The flow imped-
ance of the short section of gas line connecting the internal
volume 282 with the service port 288 is approximately 25
times smaller than that of the first 268 and third 272 gas lines
in the viscous flow regime and 11 times smaller in the
molecular flow regime. Service port 288 allows evacuation
of the triple-point cell internal volume to lower ultimate
pressures than are possible using the first 268 and third 272
gas lines alone.

Triple point immersion cell article 200 can be made in
various ways. In an embodiment, a process for making triple
point immersion cell article 200 includes forming copper
heat-exchange fins 284.5 on thermowell fin tube 284.1 by
furnace brazing processes; forming thermowell feed cap 260
on thermowell guide tube 284.2 by tungsten-inert-gas (TIG)
welding; disposing thermowell fin tube 284.1 on vapor
chamber lid 262 by TIG welding; disposing burst disc 264
on vapor chamber lid 262 by TIG welding; disposing first
gas line 268, second gas line 270, and third gas line 272 on
vapor chamber lid 262 by TIG welding; disposing clamp
collar 266 on thermowell extension tube 284.3 by fasteners;
extending a length of first gas line 268, second gas line 270,
and third gas line 272 by gasket sealed VCR-type gas line
coupler 274; disposing vapor chamber lid 262 on thermow-
ell guide tube 284.2 by TIG welding: disposing thermowell
guide tube 284.2 onto fourth cryochamber upper plate
250.50 by fasteners using clamp collar 266; disposing fourth
cryochamber upper plate 250.50 on fourth cryochamber ring
flange 250.52 by M3 fasteners; disposing fourth cryocham-

ber ring flange 250.52 on fourth cryochamber 226 by 3

soldering; disposing thermowell guide tube 284.2 onto third
cryochamber upper plate 250.14 by fasteners using clamp
collar 266; disposing third cryochamber upper plate 250.14
onto third cryochamber ring flange 250.15 by M3 fasteners;
disposing second cryochamber heat exchange flange 250.13
‘on second cryochamber base plate 250.32 by fasteners;
disposing second cryochamber base plate 250.32 on second
cryochamber ring flange 250.16 by TIG welding; disposing
thermowell guide tube 284.2 onto second cryochamber heat
exchange flange 250.13 by fasteners and crushed indium
wire; connecting second cryochamber base plate 250.32 to
first cryochamber shield top ring flange 250.9 by M3 fas-
teners: disposing first cryochamber bottom plate 250.11 on
first cryochamber tail-section ring flange 250.30 by fasten-
ers; disposing first cryochamber shield bottom ring flange
250.10 on first cryochamber bottom plate 250.11 by fasten-
ers; disposing first cryochamber top plate 250.8 on first
cryochamber shield top ring flange 250.9 by fasteners;
disposing first cryochamber inner plate 250.12 on first
cryochamber top plate 250.8 by fasteners and copper wire
thermal straps; disposing thermowell extension tube 284.3
onto first cryochamber inner plate 250.12 by fasteners and
crushed indium wire; connecting first cryochamber top plate
250.8 to primary base flange 250.2 by fasteners and fiber-
glass fixed upper support bushings 278.1; disposing lower
base flange 250.5 on tail section flange 250.7 by ISO clamps
and fasteners; disposing nipple lower flange 250.4 on lower
base flange 250.5 by ISO clamps and fasteners; disposing
primary base flange 250.2 on nipple upper flange 250.3 by
ISO clamps and fasteners; disposing service flange 250.1 on
primary base flange 250.2 by ISO half-clamps and fasteners;
disposing thermowell extension tube 284.3 in the thermow-
ell-thermometer seal fitting via TIG welding; disposing the
thermowell-thermometer seal fitting into the O-ring sealed
threaded coupling 260 by fasteners; disposing the O-ring-
sealed threaded coupling onto the service flange 250.1 by
fasteners; connecting first gas line 268, second gas line 270,

S

40

&

12

and third gas line 272 to service flange 250.1 by TIG welded
ISO flanges and clamps; disposing second cryocooler 232
and first cryocooler 230 on primary base flange 250.2 by
bellows-coupled ISO flanges and fasteners; connecting first
cryocooler 230 to first cryochamber 212 by copper-wire
thermal straps and fasteners; and connecting second cryo-
cooler 232 to second cryochamber 216 by copper-wire
thermal straps and fasteners.

Triple point immersion cell article 200 has numerous
advantageous and unexpected benefits and uses. In an
embodiment, with reference to FIG. 25, a process (300) for
determining the triple point of non-metallic analyte 210 with
triple point immersion cell article 200 includes: evacuating
vacuum chamber 236 (step 302); operating cryocoolers 230
and 232 to pre-cool interior zones so that the interior zone
achieve their base temperature (step 304); opening valve 242
to flow non-metallic analyte 210 into triple point cell interior
volume 282 and partially condense (step 306); inserting an
immersion cooler in thermowell 284 to complete conden-
sation and initiate freezing of non-metallic analyte 210 (step
308); removing the immersion cooler and introducing a
calibrated long-stem check SPRT (step 310); flowing helium
heat-exchange gas 238 in thermowell 284 (step 312): adjust-
ing set point temperatures for the cryochambers to a selected
value for the non-metallic analyte (step 314); waiting for
equilibration of temperatures (step 316); pulse heating of the
triple point cell pressure vessel in energy increments of
approximately 2% melted fraction of the known enthalpy of
fusion for the mass of condensed non-metallic analyte 210
(step 318); acquiring data for SPRTs as pulse melting
continues and the frozen analyte starts to melt (step 320);
adjusting the set point of the fourth cryo-zone to the adia-
batic condition (step 322); continuing pulse melting with
long recovery intervals and approximately 10% melted
fraction (MF) pulse duration (step 324); suspending, near
MF=50%, pulse heating (step 326); removing check SPRT
(step 328); cycling other SPRTs under test into and out of
thermowell 284 in turn (step 330); returning to the original
check SPRT upon completion of the calibration cycle (step
332); resuming pulse melting (step 334); resetting, when
non-metallic analyte 210 is completely melted, the third
cryo-zone and fourth cryo-zone to be off and removing
SPRT (step 336): reinserting immersion cooler and refreez-
ing non-metallic analyte 210 (step 338); and optionally
repeating the process starting with the repetition entry step
310.

Triple point immersion cell article 200 and processes
disclosed herein have numerous beneficial uses, including
calibration of SPRTs, realization of an in-house temperature
scale, verification of other fixed-point cells, and provision of
national metrology institute (NMI) traceable article for
laboratory accreditation. Triple point immersion cell article
200 and processes herein advantageously provide ready
adaptability to different non-metal fixed points using differ-

‘5 ent non-metal analytes having triple points from 80 K to 200

K. Beneficially, triple point immersion cell article 200
overcomes limitations of technical deficiencies of conven-
tional articles such as those employing liquid-nitrogen pool
boiling (LNPB). The LNPB process limits the possible
applications to non-metal analytes having triple points near
to or just above the range of temperatures achievable via
saturated vapor pressures of liquid nitrogen. Further, the
open cycle nature of the LNPB process necessitates inter-
ruptions and thermal perturbations associated with refilling

5 reservoirs to compensate volume evaporation.

Moreover, triple point immersion cell article 200 and
processes herein has a design advantage over the conven-


US 11,204,288 B2

5

pressure can be from vacuum to 20 bar. Moreover, first gas
line 268 provides flow of gas analyte into or out of the triple
point cell interior volume 282 or, under static conditions,
equilibrates with condensed phase portions to saturated
vapor pressures or otherwise according to known equation
of state conditions. In an embodiment, gas analyte includes
high purity argon, krypton, or xenon in solid, liquid, vapor
or supercritical gas phases.

Second gas line 270 is received by and fed through service

flange 250.1. Second gas line 270 receives helium gas and |

communicates helium into thermowell 284 via heat-ex-
change flange 250.13. The pressure of helium gas can be
from vacuum to 1.3 bar, specifically a continuous flow of
100 cm*/min helium may be maintained at an approximate
regulated inlet pressure of 1.1 bar when discharged to 1.0 bar
ambient pressure. Moreover, the helium gas temperature can
approximately equilibrate with the temperature of the heat-
exchange flange 250.13 and convey a continuous cooling to
the interior of the thermowell 284. In an embodiment, the
helium gas provides additional distributed cooling to the
thermowell 284 and to any thermometers which are placed
therein.

Third gas line 272 is received by and fed through service
flange 250.1. Third gas line 272 communicates the non-
metal gas analyte and gas analyte from gas tanks 240 into the
triple point cell interior volume 282 and is in parallel and
redundant with that of first gas line 268. In an embodiment,

a third gas line is functionally and operationally equivalent _
to the first gas line 268 and provides redundancy to enhance °

safety and reliability to the immersion cell article.
Non-metallic analyte 210 is received by first gas line 268
or third gas line 272 and communicated to or from triple

point cell interior volume 282. Non-metallic analyte 210 can,

3

include a noble gas or fluorocarbon having a triple point ~

temperature from 80 K to 200 K. Exemplary non-metallic
analyte 210 includes high purity argon. As used herein, the
triple point of pure argon is 83.8058 K with a saturated vapor
pressure of 0.69 bar. A pressure of non-metallic analyte 210
can be from vacuum to 20 bar when volumes have reached
300 K temperature and all pressurized volumes are designed
to specifications well above the nominal 20 bar limit.
Moreover, non-metallic analyte 210 can be in a sub-critical
or a supercritical state at 300 K and provide final state
pressures are 20 bar or less. Gas tanks 240 are protected with
independent burst disks for pressurization. In addition, triple
point cell pressure vessel 234 includes burst disc 264 set to
within 10% of its test pressure value of 120 bar, which is six
times a storage pressure of 20 bar at 300 K. In an embodi-
ment, non-metallic analyte 210 includes noble gasses or
stable inert fluorocarbons with chemical purities of at least
0.999995% and having triple point temperatures from 83 K
to 170K,

Flanges, chambers, and other hardware can be intercon-
nected by permanent fixturing or metal joinery such as a
weld, braze, solder, and the like. In certain embodiment,
flanges, chambers, and other hardware are de-mountable and
can be interconnected and attached to one another via a
fastener such as clamp 252, a bolt, screw, compression, and
the like. Flanges can have sealing surface that include
provision (e.g., a gland and the like) for receipt of a gasket
(a metal, elastomer, or the like), O-ring, and the like. As used
herein, “de-mountable” refers to components that are readily
disassembled and reassembled using fasteners. In an
embodiment of triple point immersion cell article 200, first
cryochamber 212, second cryochamber 216, third cryo-

40

6

chamber 220, fourth cryochamber 226, and triple-point cell
pressure vessel 234 are reversibly demountable and re-
mountable from one another.

Flanges, chambers, and other structural hardware can
include welded stainless-steel cylinders, stainless steel
plates, welded aluminum cylindrical shells, aluminum
plates, braised and or welded copper cylindrical shells, and
copper plates to contain gas or sustain vacuum and to
conduct heat and can be components to the vacuum cham-
ber, cryochambers, or pressure vessel. Exemplary flanges,
chambers, and other structural hardware are formed from
standardized demountable vacuum flanges defined under
ISO specifications. Moreover, the thermal and structural
design of the overall article 200. Flanges, chambers, and
other structural hardware can maintain a pressure from
vacuum to 1.1 bar, specifically from 10-7 mbar to 10-° mbar
under 300 K conditions, and more specifically to pressures
below 10-7 mbar when interior regions of the vacuum
chamber have been cooled to their final base temperatures.
Flanges, chambers, and other structural hardware can sustain
temperatures from below 60 K up to at least 373 K, without
damage or other adverse effects. Moreover, weld joints,
braze joints, and demountable joints can accommodate
stresses induced by differential thermal expansions over the
full range of normal temperature excursions.

Vacuum chamber housing 236 can include cylindrical
shells to form the main body and tail sections and can be
rolled aluminum or stainless-steel tubes. Exemplary vacuum
chamber housing 236 include rolled seamed aluminum
tubing. Moreover, welded aluminum and stainless-steel tub-
ing are easily joined to ISO flanges of like material for
vacuum tight joints. Vacuum chamber housing 236 can
provide modular sections to facilitate assembly/disassembly
and convenient access to all internal chambers. In an
embodiment, vacuum chamber housing 236 can be mono-
lithic or multi-component. In an embodiment, vacuum
chamber housing 236 includes one primary section 236.2
from rolled-aluminum welded-seam tubing and one tail
section 236.1 of rolled stainless steel welded-seam tubing,
and is coupled together via vacuum chamber lower base
flange 250.5, vacuum chamber nipple lower flange 250.4
coupled to vacuum chamber housing tail section flange
250.7, and vacuum chamber nipple upper flange 250.3 with
vacuum chamber primary base flange 250.2 coupled to
vacuum chamber nipple upper flange 250.3, and vacuum
chamber service flange 250.1 and vacuum port (pump-out)
flange 250.6 as shown in in FIG. 2, FIG. 3, FIG. 4, FIG. 5,
FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, and FIG. 11.

First cryochamber 212 can include a metal shell assembly
to approximate an isothermal boundary that is strongly
thermally coupled to the absorber of the first cryocooler and
weakly thermally coupled to the external environment
Exemplary first cryochamber 212 include all-welded alumi-
num or brazed copper shells with control sensors. Moreover,

5 the first cryochamber assembly facilitates mechanical sup-

port of itself and all other internal chambers via a set of
threaded fiberglass spacers 278. Specifically, certain sup-
ports 278.2 are adjustable to compensate for small misalign-
ments that may occur between the geometric axes of other
internal cryochambers. First cryochamber 212 can provide
thermal isolation from ambient heat sources to other internal
cryochambers, specifically isolation of the heat from the
external environment to the second, third, and fourth cryo-
chambers 216, 220, and 226, and more specifically to the

5 triple-point cell pressure vessel 234. In an embodiment, first

cryochamber 212 can be monolithic or multi-component. In
an embodiment, first cryochamber 212 is multi-component


U.S. Patent

200

Dec. 21, 2021

Sheet 5 of 25

US 11,204,288 B2

258.3

Cee! 250.12
250.8

278

250.82:
280

250.9
fp 236.2

250.11

te

po 20.13
212.2

250.10

250.4

250.5

250.6 “he.

250.80

250.50:

J
250.52 |

250.14

256-44

250.15
250.7

1 264

p——- 262

234
[226
220
7216
p—~ 212.1
bm 236. 1

Figure. 5


U.S. Patent Dec. 21, 2021 Sheet 4 of 25 US 11,204,288 B2

— 236.2

242.2



U.S. Patent Dec. 21, 2021 Sheet 17 of 25 US 11,204,288 B2

200

268.
250.13

216

ee

Figure. 17


U.S. Patent Dec. 21, 2021 Sheet 7 of 25 US 11,204,288 B2

200
276

250.5

a

nh 286.1.



U.S. Patent Dec. 21, 2021 Sheet 23 of 25 US 11,204,288 B2

200

Figure. 23


a2 United States Patent

US011204288B2

(10) Patent No.: US 11,204,288 B2

Tew, Jr. et al. (45) Date of Patent: Dec. 21, 2021
(54) TRIPLE POINT IMMERSION CELL (58) Field of Classification Search
ARTICLE CPC ....... GOIK 13/006; GOK 1/02; GO1K 1/08;
GOIK 11/06; GOIK 2203/00:
(71) Applicant: Government of the United States of (Continued)
America, as represented by the (56) References Cited

Secretary of Commerce, Gaithersburg,
MD (US)

(72) Inventors: Weston Leo Tew, Jr., Clarksburg, MD
(US); Jay Robert Nanninga, Monrovia,
MD (US)

GOVERNMENT OF THE UNITED
STATES OF AMERICA, AS
REPRESENTED BY THE
SECRETARY OF COMMERCE,
Gaithersburg, MD (US)

(73) Assignee:

(*) Notice: Subject to any disclaimer, the term of this,

patent is extended or adjusted under 35
U.S.C, 154(b) by 278 days.

(21) Appl. No.: 16/567,765
(22) Filed: Sep. 11, 2019

(65) Prior Publication Data
US 2021/0072098 Al Mar. 11, 2021

(51) Int. CL
GOIK 108
GOIK 13/00

(2021.01)
(2021.01)

(Continued)

GO1K 13/006 (2013.01); GO1K 1/02

(2013.01); GOIK 1/08 (2013.01); GOIK 11/06
(2013.01);

(Continued)

U.S. PATENT DOCUMENTS

4,211,085 A * 7/1980 Tyree, Jr. FI7C 5/02
62/165
4,734,116 A * 3/1988 Ehrsam F25C 1/16
62/532

(Continued)

OTHER PUBLICATIONS

Furukawa, G.T,,et al., “Triple Point of Argon”, Temp. Meas. Contr
Sci. Indus., 1972, p. 231-243, vol. 4.

(Continued)

Primary Examiner — Gail Kaplan Verbitsky
(74) Attorney, Agent, or Firm — Office of Chief Counsel
for National Institute of Standards and Technology

(57) ABSTRACT

Atriple point immersion cell article determines a triple point
of a non-metallic analyte and includes: a first eryochamber
including a first cryo-zone; a second cryochamber including
a second cryo-zone that is: nested and disposed in the first
cryochamber; and thermally isolated by the first cryocham-
ber; a third cryochamber including a third cryo-zone, the
third cryochamber being: nested and disposed in the second
cryochamber, thermally isolated from the exterior environ-
ment by the first cryochamber and the second cryochamber;
and thermally isolated from the first cryochamber by the
second cryochamber; and a fourth cryochamber including a
fourth cryo-zone disposed in the third cryochamber; a triple-
point pressure vessel disposed in the fourth cryochamber;
and a thermowell disposed in the triple-point pressure ves-
sel.

19 Claims, 25 Drawing Sheets



U.S. Patent Dec. 21, 2021 Sheet 10 of 25 US 11,204,288 B2

200 268 270 272

4

i BOB

250.7

i Np 286.1

Figure. 10


U.S. Patent Dec. 21, 2021 Sheet 9 of 25 US 11,204,288 B2

200

250.5

4.

236.1

“Steen”

Figure. 9


US 11,204,288 B2

9

thermal coupling to non-metallic analyte 210 via thin copper
fins that extend radially into sections of triple-point cell
interior volume 282. In an embodiment, thermowell 284 can
be monolithic or multi-component. In an embodiment, ther-
mowell 284 is multi-component and includes: a lower-most
section of stainless steel tubing 284.1 with copper heat-
exchange fins 284.5; an intermediate section of stainless
steel tubing 284.2 to facilitate thermometer guidance and
mechanical support of inner cryo-zones; an upper section of
stainless steel tubing 284.3 that extends to vertical dimen-
sion of the thermowell; and gas-seal fitting 284.4 for making
gas-tight connections to long-stem thermometer sheaths. In
an embodiment, thermowell 284 is in thermal communica-
tion with first cryo-zone 214, second cryo-zone 218, third
cryo-zone 222, and fourth cryo-zone 228 and is in mechani-
cal communication supported via second cryochamber heat
exchange flange 250.13. In an embodiment, thermowell 284
receives helium as a heat exchange gas 238 at a pressure
from 1 bar to 1.1 bar, and more specifically is sealed to heat
exchange flange 250.13 using crushed-indium-wire seals at
the uppermost section of thermowell guide tube 284.2 and
the lowermost section of thermowell extension tube 284.3.
Thermowell fin tube 284.1 can include a section of metal
tubing with similar or dissimilar metal fins to extend the
effective surface area of the tube’s exterior. Moreover, the
heat-exchange surfaces must extend into regions of the
triple-point cell interior volume 282 containing at least one
condensed phase of the non-metallic analyte. Thermowell
fin tube 284.1 can achieve thermal equilibration between

itself and one or both condensed phases of the non-metallic 3

analyte 210. In an embodiment, thermowell fin tube 284.1
includes a helical strip of copper heat-exchange fins 284.5
that is brazed onto its exterior surface

First cryochamber 212, second cryochamber 216, third

cryochamber 220, fourth cryochamber 226, respectively 3

provide first cryo-zone 214, second cryo-zone 218, third
cryo-zone 222, fourth cryo-zone 228. As used herein, cryo-
zone refers to regions of the interior volume which will
equilibrate to temperatures near that of the associated cryo-
chamber surfaces. Moreover, the four cryo-zones are weakly
thermally coupled to each other. The fourth cryo-zone
approximates an adiabatic zone as far as heat exchange
between the fourth cryochamber and triple-point cell pres-
sure vessel is concerned. As used herein, adiabatic zone
refers to conditions where heat transported between bodies
is 10 microWatts or less. Moreover, the adiabatic zone is
accomplished via balancing a small residual cooling power
with a small applied heating power using a combination of
differential thermocouples and high-accuracy SPRTs located
in fourth cryochamber 226 and internal equilibration block
286. Fourth cryo-zone 228 is an adiabatic zone with respect
to a triple point transition temperature of non-metallic
analyte 210.

‘Triple point immersion cell article 200 includes cryo-
zones that are generated by active cooling. Under active
cooling, heat is removed over the entire cryochamber by
thermally coupling all segments to a heat absorbing surface.
It is contemplated that first cryo-zone 214 and second
cryo-zone 218 are subjected to closed-cycle refrigeration in
an absence of a liquid cryogen. As used herein, “cryogen”
refers to a substance that may be readily condensed into a
liquid phase at moderate or low saturated pressure. As used
herein, “liquid cryogen” refers to a bulk condensed material
undergoing open-cycle pool boiling in saturated vapor con-
ditions. In contrast, as used herein, “closed-cycle refrigera-
tion” refers to machines operating in continuous thermody-
namic cycles with a fixed amount of gas-phase helium. In

2

40

&

10

this regard, first cryocooler 230 actively cools first cryo-
chamber 212 to produce first cryo-zone 214, and second
cryocooler 232 actively cools second cryochamber 216 to
produce second cryo-zone 218. It is contemplated that third
cryo-zone 222 is passively cooled, wherein ordinary con-
duction through the thermowell guide tube 284.2 can pro-
vide approximately 22 mW/K over a 1 cm length at 80 K.
Third cryo-zone 222 is subjected to active thermal control to
a constant temperature, wherein the constant temperature set
point is approximately (0.1+0.02) K below the triple point
temperature of the non-metal analyte. It is contemplated that
fourth cryo-zone 228 is passively cooled via third cryo-zone
222, wherein ordinary conduction through the thermowell
guide tube 284.2 can provide approximately 22 mW/K over

s al cm length at 80K. Fourth cryo-zone 228 is adiabatic with

respect to the triple-point cell pressure vessel 234 and
internal equilibration block 286. It should be appreciated
that third cryo-zone 222 temperature is maintained approxi-
mately 0.1 K below that of fourth cryo-zone 228 as a
consequence of the adiabatic conditions maintained between
the triple point cell pressure vessel 234 and the fourth
cryochamber 226 as shown in FIG. 24. Referring to FIG. 24,
T3=T4-0.1 K; T2=T3-1.0 K; and T5=12+20 K, allowing
for margins of error between 10% and 20% of the stated

S temperature differences.

In an embodiment, a pressure of first cryochamber 212,
second cryochamber 216, third cryochamber 220, and fourth
cryochamber 226 is high-vacuum, specifically less than 1
microbar when all cryochambers are below 200 K. In an
embodiment, first cryo-zone 214, second cryo-zone 218,
third cryo-zone 222, and fourth cryo-zone 228 are subjected
to active control of their respective temperature.

With reference to FIG. 11, removal of primary base flange
250.2 and vacuum chamber housing primary section 236.2
exposes first cryochamber top plate 250.8, first cryochamber
inner plate 250.12, fixed upper support bushing 278.1, gas
line coupler 274, and clamp collar 266. First cryochamber
top plate 250.8 is the uppermost section of first cryochamber
212 and is disposed on first cryochamber shield top ring
flange 250.9 of first cryochamber 212.2. First cryochamber
inner plate 250.12 is a mechanically-decoupled segment of
the first cryochamber 212. Upper support bushing 278.1 can
include combinations of fiberglass and threaded stainless
steel fasteners. A total of three support bushings 278.1 are in

5 tension and support the combined weight of all interior

elements. Gas line coupler 274 all-metal gasketed fittings.
Exemplary gas line couplers 274 include VCR-type fittings

Moreover, these fittings must be vacuum tight against
helium or other gas leaks at the nominal detection limit of
10-° std. cm?/s leak rates when thermally cycled through
ranges of 80 K to 300 K. Clamp collar 266 split collar types
of stainless-steel supplying radial clamping forces and that
remain in compression over multiple thermal cycles between
80 K and 300 K. Clamp collar 266 provides sufficient

5 interfacial forces to provide adequate thermal contact

between the thermowell guide tube 284.2 and other cryo-
chamber components.

In an embodiment, with reference to FIG. 2, triple point
immersion cell article 200 is disposed on mount plate 248 of
cart 246. Cart 246 can include side rails 300, transverse rails
302, brackets 304, and casters 306 to stabilize and provide
mobility to triple point immersion cell article 200.

‘Triple-point cell internal volume 282 is also accessible via
internal service port 288. Service port 288 allows internal

5 volume 282 to be flushed and purged with a source of pure

gas analyte 210 prior to final assembly of the article 200 or
during service intervals. Service port 288 is capped-off with


US 11,204,288 B2

7
and includes welded aluminum cylindrical shells 212.1 and
212.2, flanges 250.9, 250.10 and 250.16, and demountable
aluminum plates 250.8, 250.11 and 250.12. as shown in in
FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 10, FIG. 11, FIG. 12,
FIG. 13, FIG. 14, and FIG. 15.

Second cryochamber 216 can include a metal plate and
shell assembly to approximate an isothermal boundary that
is strongly thermally coupled to the absorber of the second
cryocooler and weakly thermally coupled to the first cryo-
chamber. Exemplary second cryochamber 216 include alu-
minum plates and welded aluminum cylindrical shells with
control sensors. Moreover, the second cryochamber assem-
bly facilitates mechanical support of and alignment of itself
via a set of adjustable turnbuckle support bushings 278.2.
Second cryochamber 216 can provide thermal isolation from
stray heat sources to all other internal cryochambers, spe-
cifically isolation of the heat from the first cryochamber to
the third, and fourth cryochambers 220, and 226, and more
specifically to the triple-point cell pressure vessel 234. The
second cryochamber 216 also cools the incoming helium
heat exchange gas via the heat exchange flange 250.13
before it enters the thermowell 234. Moreover, the achiev-
able base temperature for the second cryochamber deter-
mines the coldest point the entire triple point immersion cell
article 200, the coldest point along the axis of the thermow-
ell 284 and in turn the available cooling power to the third
and fourth cryochambers 220, and 226. Moreover, the
second cryochamber 216 establishes an isothermal cryo-
zone 218 that is controlled at a set point approximately 1 K
below the triple point temperature of the non-metal analyte.
In an embodiment, second cryochamber 216 includes alu-
minum and copper plates and welded aluminum cylindrical
shells. In an embodiment, second cryochamber 216 can be
monolithic or multi-component. In an embodiment, second

cryochamber 216 is multi-component and includes base 3

plate 250.32 coupled to second cryochamber ring flange
250.16 as welded to the tail section cylindrical shield, and
heat exchange flange 250.13 as shown in in FIG. 3, FIG. 4,
FIG. 5, FIG. 6, FIG. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16,
and FIG. 17.

Third cryochamber 220 can include a thin metal shell,
sensors and heaters. Exemplary third cryochamber 220
include aluminum or copper demountable cylindrical shells.
Moreover, the third cryochamber is weakly thermally
coupled to the second cryochamber 216 and mechanically
supported via the thermowell 284. Third cryochamber 220 is
passively cooled and actively controlled such that it can
provide moderate isolation from temperature variations in
the second cryochamber 216 and some thermal isolation to
the fourth cryochamber 226, and more specifically to the
triple-point cell pressure vessel 234. Moreover, the third
cryochamber 220 establishes an isothermal cryo-zone 222
that is controlled at a set point approximately 0.1 K below
the triple point temperature of the non-metal analyte with a
short-term stability of approximately +20 mK. In an embodi-
ment, third cryochamber 220 includes copper plates and
welded copper cylindrical shells, heaters and platinum resis-
tance thermometers. In an embodiment, third cryochamber
220 can be monolithic or multi-component. In an embodi-
ment, third cryochamber 220 is multicomponent and
includes upper plate 250.14 coupled to ring third cryocham-
ber ring flange 250.15 as shown in in FIG. 5, FIG. 6, and
FIG. 18.

Fourth cryochamber 226 can include a thin metal shell,
sensors and heaters. Exemplary fourth cryochamber 226
include aluminum or copper demountable cylindrical shells.
Moreover, the fourth cryochamber 226 is moderately ther-

S

&

8

mally coupled to the third cryochamber 220 and mechani-
cally supported via the thermowell 284. Fourth cryochamber
226 is passively cooled and actively controlled such that it
can provide moderate isolation from temperature variations
in the third cryochamber 220 and a high degree of thermal
isolation to the triple-point cell pressure vessel 234. It is
contemplated that fourth cryo-zone 228 establishes near-
adiabatic conditions for the triple-point cell pressure vessel
234 with heat leaks of approximately 10 microwatts or less

Moreover, the adiabatic cryo-zone 228 is controlled at a set
point approximately +1 mK from the triple point tempera-
ture of the non-metal analyte with a short-term stability of
approximately +1 mK and such conditions are necessary to
provide a stable and reproducible melt plateau for non-
metallic analyte 210. In an embodiment, fourth cryochamber
226 includes copper plates and welded copper cylindrical
shells, heaters and platinum resistance thermometers. In an
embodiment, fourth cryochamber 226 can be monolithic or
multi-component. In an embodiment, fourth cryochamber
226 is multi-component and includes upper plate 250.50
coupled to ring flange 250.52 as shown in in FIG. 5, FIG. 6,
and FIG. 19.

The triple-point cell pressure vessel 234 encloses the
triple-point cell interior volume 282 and receives a long-
stem thermometer via the thermowell 284 for calibration at
the triple point of non-metallic analyte 210. The pressure
vessel 234 is joined to the thermowell 284 via the vapor
chamber lid 262. The lower section of the pressure vessel
234 is terminated with an internal equilibration block 286.
Both the thermowell and the internal equilibration block 286
serve to equilibrate thermometers with the non-metallic
analyte 210. In an embodiment, triple-point cell pressure
vessel 234 is made from all-welded stainless-steel sections
that includes vapor chamber lid 262 with burst disc 264 and
internal equilibration block 286 disposed thereon as shown
in in FIG. 5, FIG. 6, FIG. 20, FIG. 21, and FIG. 22.

The long-stem thermometer can include any of several
varieties of quartz or metal-sheathed types of length 48 cm
or greater and outer diameters between 6.35 mm and 7.5
mm. Exemplary long-stem thermometers include a 25.5-
ohm standard platinum resistance thermometer (SPRT).
Moreover, such SPRTs equilibrate with the non-metal ana-
lyte via the thermowell fin tube 284.1 and are used to both
evaluate the melting plateau of the non-metal analyte and
facilitate comparison of the plateau temperatures with that of
other triple-point temperature standards.

The capsule-type thermometer can include any or several
varieties of glass or platinum-sheathed types with internal
helium atmospheres. Exemplary capsule-type thermometers
include capsule-type 25.5 Ohm Standard Platinum Resis-
tance Thermometers (SPRTs). Moreover, such SPRTs equili-
brate with the non-metal analyte via the internal equilibra-
tion block 286 and are used to establish the melt-to-melt
reproducibility of the non-metallic analyte’s triple point
temperature.

Thermowell 284 can include certain sections or segments
to facilitate insertion and removal of long-stem SPRTs into
and out of the triple-point cell pressure vessel 234 and
thermally couple to the non-metallic analyte 210. Exemplary
thermowells 284 include various metal tubing as joined to
the body of the triple-point cell pressure vessel 234 and are
thermally coupled the non-metallic analyte 210 over regions
of the triple-point cell interior volume 282. Moreover,
thermowell 284 is thermally coupled to the non-metallic

5 analyte 210 over a vertical region of the triple point cell

interior volume 282 in excess of 15 cm known as the
immersion depth. Moreover, thermowell 284 can provide


U.S. Patent Dec. 21, 2021 Sheet 6 of 25 US 11,204,288 B2

250.2

250.8 ~ af

250.6 ‘ j 2 250.8
i f 250.9
250.13

250.11 212.2
250.14
250.15

rs

Figure. 6


U.S. Patent Dec. 21, 2021 Sheet 20 of 25 US 11,204,288 B2

200

268 270 pune

274
272 268
a4 = 266 ono
eh
270 j
266 /
274 Ly
‘ aT 270 274
268 | 288
270

a 2

—
Figure. 20


US 11,204,288 B2

1
TRIPLE POINT IMMERSION CELL
ARTICLE

STATEMENT REGARDING FEDERALLY
SPONSORED RESEARCH

This invention was made with United States Government
support from the National Institute of Standards and Tech-
nology (NIST), an agency of the United States Department
of Commerce. The Government has certain rights in the
invention. Licensing inquiries may be directed to the Tech-
nology Partnerships Office, NIST, Gaithersburg, Md.,
20899; voice (301) 301-975-2573; email tpo@nist.gov.

BRIEF DESCRIPTION

Disclosed is a triple point immersion cell article for
determining a triple point of a non-metallic analyte, the
triple point immersion cell article comprising: a first cryo-
chamber comprising a first cryo-zone; a second cryocham-
ber comprising a second cryo-zone, the second cryochamber
being: nested and disposed in the first cryochamber; and
thermally isolated from an exterior environment of the triple
point immersion cell article by the first cryochamber; a third
cryochamber comprising a third cryo-zone, the third cryo-
chamber being: nested and disposed in the second cryo-
chamber; thermally isolated from the exterior environment
by the first cryochamber and the second cryochamber; and
thermally isolated from the first cryochamber by the second

cryochamber; a fourth cryochamber comprising a fourth 3

cryo-zone, the fourth cryochamber being: nested and dis-
posed in the third cryochamber; thermally isolated from the
exterior environment by the first cryochamber, the second
cryochamber, and the third cryochamber; and thermally

isolated from the second cryochamber by the third cryo- 3

chamber; and a triple-point pressure vessel comprising a
fifth cryo-zone, the triple-point pressure vessel being: nested
and disposed in the fourth cryochamber; thermally isolated
from the exterior environment by the first cryochamber, the
second cryochamber, the third cryochamber, and the fourth
cryochamber; and thermally isolated from the third cryo-
chamber by the fourth cryochamber; and a thermowell
disposed in the triple-point pressure vessel, the triple-point
pressure vessel being directly accessible from the exterior
environment via thermowell.

Disclosed is a process for determining a triple point of a
non-metallic analyte with the triple point immersion cell
article, the process comprising: evacuating a vacuum cham-
ber in which the first cryochamber is disposed; cooling the
first cryo-zone, the second cryo-zone, the third cryo-zone,
and the fourth cryo-zone with a cryocooler; flowing the
non-metallic analyte into the triple point cell interior volume
to partially condense the non-metallic analyte: inserting an
immersion cooler in the thermowell to complete condensa-
tion of the non-metallic analyte; initiating freezing of the
non-metallic analyte; removing the immersion cooler; intro-
ducing a calibrated standard platinum resistance thermom-
eter into the thermowell; flowing helium heat-exchange gas
in the thermowell; adjusting a set point temperature of each
of the first cryochamber, the second cryochamber, the third
cryochamber, and the fourth cryochamber to a selected value
for the non-metallic analyte; pulse heating of the triple point
cell pressure vessel in energy increments; adjusting a set
point of the fourth cryo-zone to an adiabatic condition;
suspending pulse heating; removing the calibrated standard
platinum resistance thermometer; disposing a test standard
platinum resistance thermometer into thermowell; removing

0

2

40

45

2

the test standard platinum resistance thermometer from the
thermowell; re-disposing the calibrated standard platinum
resistance thermometer in the thermowell; resuming pulse
melting: completely melting the non-metallic analyte; rein-
serting the immersion cooler into the thermowell; and
refreezing the non-metallic analyte to determine the triple
point of the non-metallic analyte.

BRIEF DESCRIPTION OF THE DRAWINGS.

The following description should not be considered lim-
iting in any way. With reference to the accompanying
drawings, like elements are numbered alike

FIG. 1 shows a triple point immersion cell article;

FIG. 2 shows a perspective view of a triple point immer-
sion cell article;

FIG. 3 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with certain portions
having high transparency;

FIG. 4 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with certain portions
being shaded;

FIG. 5 shows a cross-section of the triple point immersion

Ss cell article shown in FIG. 2;

FIG. 6 shows a cross-section in a perspective view of the
triple point immersion cell article shown in FIG. 2;

FIG. 7 shows a perspective view of the triple point
immersion cell article shown in FIG. 2;

FIG. 8 shows a top view of the triple point immersion cell
article shown in FIG. 2;

FIG. 9 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 without cryocoolers;

FIG. 10 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with vacuum cham-
ber housing viewable:

FIG. 11 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with vacuum cham-
ber housing viewable;

FIG. 12 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with vacuum cham-
ber housing viewable:

FIG. 13 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with vacuum cham-
ber housing viewable;

FIG. 14 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with vacuum cham-
ber housing viewable;

FIG. 15 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a first cryo-
chamber viewable;

FIG. 16 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a second

5 cryochamber viewable;

FIG. 17 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a second
cryochamber viewable;

FIG. 18 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a third cryo-
chamber viewable;

FIG. 19 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a fourth
cryochamber viewable;

FIG. 20 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a thermowell
viewable;


U.S. Patent Dec. 21, 2021 Sheet 2 of 25 US 11,204,288 B2

200

see 250.5,

236.1

Figure. 2


U.S. Patent Dec. 21, 2021 Sheet 13 of 25 US 11,204,288 B2

200

pW 272

25013

}

fp 236.1

Ne

Figure. 13


U.S. Patent Dec. 21, 2021 Sheet 15 of 25 US 11,204,288 B2

200
268

270 PR 272

268 ft
250.13 et 2 250.82

nen 250.10

Te 212.2

nd

Figure. 15


U.S. Patent Dec. 21, 2021 Sheet 1 of 25 US 11,204,288 B2

240.1 240.2

7
nN

2387 Pp 210
232 230

i 244 244
242 242
236 224 244 [~244
/_)

{
¢
234
t—~ 282
4 +H 284
286—__| +4 +] _
<4 228
cH
‘ »
26 —— | eT, PT
7_—]—|_]_1
(ct vt
212 214 216 218 220 222 226

Figure. 1


U.S. Patent

Temperature —>

Dee. 21, 2021 Sheet 24 of 25 US 11,204,288 B2
T6 J
TH °
Adiabatic
condition
[4 —p nnn nnn enn e nee nnn ene e nee eee On-n------ Wann nnn nnn ee ee
TR e
TR °
ZO CZi CZ2 CZ3 CZ4 CZ5
214 218 222 228 282
Zone

Figure. 24


US 11,204,288 B2
Page 2

(51) Int. CL
GOIK 11/06 (2006.01)
GOIK 1/02 (2021.01)
GOIN 25/12 (2006.01)
(52) US. CL
CPC vise, GOIK 2203/00 (2013.01); GOIN 25/12

(2013.01)
(58) Field of Classification Search
CPC .... GOIK 15/002: GOIK 15/005; GO1K 15/00;
GOIK 11/00; CO2E 1/22; CO2F 1/04;
CO2F 11/20; GOIN 25/12; GOIN 25/02;
GOIN 25/04
See application file for complete search history.

(56) References Cited
U.S. PATENT DOCUMENTS

5,219,225 A * 6/1993 Ball GOIK 15/002
374/1
6,293,695 BI* 9/2001 Schmermund GOIK 15/002
374/1
6,327,894 B2* 12/2001 Vaughn GOIL 5/28
303/86

6,939,035 B2* 9/2005 Machin GOIK 15/002

7,708,459 B2* 5/2010 Nakano
10,768,056 B1*
2018/0224338 Al*
2019/0003648 Al* 1/2019 Kunberger
2019/0263699 Al* 8/2019 Finger
2019/0301784 Al* 10/2019  Sillince

9/2020 Pond
8/2018 Umkehrer

GOIK 15/002
GOIK 15/005
FIC 13/028
BOLD 5/006
F25D 3/107

OTHER PUBLICATIONS

Furukawa, G.T,, et al., “Argon Triple Point Apparatus with Multiple
‘Thermometer Wells”, Temp. Meas. Cent. Sci, Indus., 1992, p.
265-269, vol. 6.

Ahmed, M.G., et al., “Argon Triple Point Device to Calibrate
Long-Stem Thermometers in Quasi-Adiabatic Conditions”, Temp
Meas. Contr. Sci. Indus., 2003, p. 172-202, vol. 7.

Yang, I., et al., “Development of the Sealed-Type Triple-Point-of-
‘Argon Cell for Long-Stem SPRT Calibration at KRISS”, Int. J
‘Thermophys, 2008, p. 1740-1748.

Fluke calibration Inc., Model 5960A Triple Point of Argon System,
http://download. flukecal.com/pub literature!422683 Ib-feal-5969-ds-
wodt.

Ding, R., et al., “Experimental Study and Computer Modeling of the
Triple Point of Argon System”, NCSLI Measure, 2012, p. 58-62,
vol. 7 No |

Pond Engineering, INe., Model K38, URL: www pondengineering,
com/s/k52_DataSheet_Jul2016.pdf, accessed Sep. 2018.

Pond Engineering, INe., Model K52, URL: www.pondengineering
com/s/k38_DataSheet_Mar2018-L pdf, accessed Sep. 2018

Pond, S.L., “Argon Triple Point Apparatus for SPRT Calibration”,
‘Temp. Meas. Contr. Sci. Indus., 2003, p. 203-208, vol. 7

Isotech Ltd., “471 Simple Argon Triple Point Apparatus”, URL:
https://www.isotech.co.uk/news/new-argon-triple-point accessed Sep.
2018.

Pavese, F., “Century—Stable Accurate Cryogenic-Temperature Fixed
Points:Problems Solved and Problems to be Solved”, Temp. Meas.
Cont. Sci. Indus., 2003, p. 167-172, vol. 7.

Pavese, F, et al., “Cryogenic Temperature Sealed Fixed Points: a
New-Generation of Modular Cells at IMGC”, Temp. Meas. Cont
Sci. Indus., 2003, p. 173-178, vol. 7.

Hermier, Y,, et al., “A New Generation of Multicells for Cryogenic
Fixed Points at BNM/INM”, Temp. Meas. Cont. Sci. Indus., 2003,
p. 179-185, vol. 7.

Kolodziej, B., et al., “Argon Triple-Point Device for Calibration of
SPRIs”, International Journal of Thermophysics, 2015, p. 229-239,
vol. 36.

Anesin, J., et al., “Argon triple point realization cryostat for
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Instruments, 1976, p. 1519-1521, vol. 47

‘Tavener, J., “Argon Triple Point”, Isotech Seminar, 2018.

* cited by examiner


US 11,204,288 B2

13

tional LNPB process. In an aspect, the geometric design
constraints associated with maximizing the size of a liquid
nitrogen reservoir are eliminated. This allows for greater
freedom in the design of the thermowell 284 and the aspect
ratio of triple point cell internal volume 282 such that the
achievable immersion depth of the cell is maximized.

Triple point immersion cell article 200 provides a com-
pact and standardized thermal platform in which triple
points of rare gas condensates or other non-metals can be
determined for calibration of a thermometer and to realize
definitions the ITS-90 and or future ITS. Triple point immer-
sion cell article 200 includes a fixed-point cell that is
referred to as an immersion-type cell, where thermowell 284
is directly accessible from the exterior of triple point immer-
sion cell article 200. A four cryo-zone configuration is
included in triple point immersion cell article 200, wherein
the first two outermost zones can be actively cooled using
Stirling-cycle cryocoolers, and the innermost two cryo-
zones provide additional control and isolation. Triple point
immersion cell article 200 can accommodate any nonmetal
fixed point from 80 K to 200 K and provides conditions for
stable and reproducible melt plateaus.

It is contemplated the triple point immersion cell article
200 provides determination of a single non-metal triple point
and accommodates immersion-type triple-point cells of
argon, krypton, xenon, or non-metal (e.g. NO, NH,
CH,OH, and the like) fixed point from 80 K to 200 K.
Advantageously, triple point immersion cell article 200

includes closed-cycle refrigeration to support immersion- 3

type non-metal triple point cells and overcome technical
limitations involved with conventional apparatus that use
liquid nitrogen pool boiling, a technology that can be viable
only for argon triple-point cells.

triple point immersion cell article 200 receives a long- 3

stem thermometer via a single externally-accessible ther-
mowell 284. In addition, triple point immersion cell article
200 can receive a capsule-type thermometer via three inter-
nal thermowells. Triple point immersion cell article 200 also
overcomes technical limitations of conventional closed-
cycle-based apparatus for non-metal triple-point cells that
only accommodate capsule-type thermometers. Miniature
triple-point cells are sequestered inside adiabatic calorim-
eters and are not accessible from the external environment
during use, i.e., during operation on a melt plateau. Accord-
ingly, triple point immersion cell article 200 accommodates
immersion-type triple point cells that provide direct access
to the cell while on the melt plateau. Triple point cell article
200 includes closed cycle refrigeration for immersion-type
argon triple point cells or other immersion-type fixed point
cells, such as the Kr and Xe triple points, for the calibration
of long-stem SPRTs. This combination of immersion type
triple-point cells for non-metals other than argon has been
unavailable in conventional apparatus due to an unsuitable
range of saturated-vapor-pressure equilibrium temperatures
associated with pool boiling of liquid nitrogen.

Triple point immersion cell article 200 can include central
50-cm long thermowell 284 that extend from an external
port into a non-metal analyte cell and continuously purged
with pre-cooled helium gas. Three additional small ther-
mowells for capsule thermometers can be accessible via the
vacuum chamber. The triple point cells are designed to be
operated in the melting mode. During melting of the non-
metal solid, the inner-most zone is set to approximate
adiabatic conditions and reduces or eliminates perturbative
heat leaks that could otherwise affect the reproducibility of
the melt plateau. An integral gas manifold and storage

S

8

2

40

3

14

volume permits gas to remain at pressures below 300 psig
when triple point immersion cell article 200 is at 300 K.
Triple point immersion cell article overcomes mainte-
nance and performance limitations of liquid-nitrogen cooled
systems for argon TP cells and operates in an absence of
liquid nitrogen. With respect to conventional apparatus,
triple point immersion cell article 200 provides thermal
stability, reproducibility, and duration of melt plateaus that
are greatly improved since the thermal transients and vari-
able gradients associated with a liquid pool are eliminated
Settings of controlled cryo-zones are unconstrained by
vapor-liquid equilibrium of nitrogen so that triple point
immersion cell article 200 provides optimized zone-tem-
perature settings. Triple point immersion cell article has an

5 effective immersion depth of the fixed-point cell that is

unconstrained by having an adequate volume of liquid
nitrogen in a reservoir above the cell.

Triple point immersion cell article 200 is modular and
standardized with demountable vacuum flanges and other
demountable fittings, wherein triple point immersion cell
article 200 can be disassembled or reassembled in the field,
enabling efficient servicing, maintenance, and low-risk shi
ping. It should be appreciated that conventional apparatus
with be pool-boiling can be bulky, not field-serviceable, and

5 difficult to ship without incurring leaks or other damage.

Triple point immersion cell article 200 and processes
herein unexpectedly provides combinations of fixed points
to be introduced and deployed for use in laboratories using
long-stem thermometers. Moreover, triple point immersion
cell article 200 can be used with any fixed-point cell having
a transition temperature from 80 K to 200 K.

While one or more embodiments have been shown and
described, modifications and substitutions may be made
thereto without departing from the spirit and scope of the
invention. Accordingly, it is to be understood that the present
invention has been described by way of illustrations and not
limitation. Embodiments herein can be used independently
or can be combined.

All ranges disclosed herein are inclusive of the endpoints,
and the endpoints are independently combinable with each
other. The ranges are continuous and thus contain every
value and subset thereof in the range. Unless otherwise
stated or contextually inapplicable, all percentages, when
expressing a quantity, are weight percentages. The
suffix “(s)” as used herein is intended to include both the
singular and the plural of the term that it modifies, thereby
including at least one of that term (e.g., the colorant(s)
includes at least one colorants). “Optional” or “optionally”
means that the subsequently described event or circumstance
can or cannot occur, and that the description includes
instances where the event occurs and instances where it does
not. As used herein, “combination” is inclusive of blends,
mixtures, alloys, reaction products, and the like.

As used herein, “a combination thereof” refers to a
combination comprising at least one of the named constitu-
ents, components, compounds, or elements, optionally
together with one or more of the same class of constituents,
components, compounds, or elements.

All references are incorporated herein by reference.

The use of the terms “a” and “an” and “the” and similar
referents in the context of describing the invention (espe-
cially in the context of the following claims) are to be
construed to cover both the singular and the plural, unless
otherwise indicated herein or clearly contradicted by con-
text. “Or” means “and/or.” It should further be noted that the
terms “first.” “second,” “primary,” “secondary,” and the like
herein do not denote any order, quantity, or importance, but


US 11,204,288 B2

3

FIG. 21 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a fin tube
viewable;

FIG. 22 shows a perspective view of the triple point
immersion cell article shown in FIG. 2 with a fin tube
viewable;

FIG. 23 shows the triple point immersion cell article
shown in FIG, 2 disposed on a cart;

FIG. 24 shows a graph of temperature versus zone for a
triple point immersion cell article; and

FIG. 25 shows a flow chart for determining a triple point
temperature.

DETAILED DESCRIPTION

A detailed description of one or more embodiments is
presented herein by way of exemplification and not limita-
tion.

It has been discovered that a triple point immersion cell
article provides a realization of a triple point temperature
with an uncertainty of less than or equal to 0.25 milliKelvin
(mK) with a long-stem thermometer. Additionally, the triple
point immersion cell article can provide the realization of
triple point temperature of a non-metallic analyte such as a
rare gas condensate. Moreover, triple point immersion cell
article is operable at a steady-state cryogenic temperature in
an absence of a liquid cryogen such as liquid nitrogen with
an uncertainty factor from chemical impurities of less than
0.1 mK. Beneficially, the triple point immersion cell article

has a thermowell with a length, e.g., an immersion depth, 3

that minimizes an immersion effect error to less than 0.0.05
mK.

Triple point immersion cell article 200 provides a repro-
ducible realization of the triple point temperature that is

independent of the exterior environment. In an embodiment, 3:

with reference to FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG.
6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG. 11, FIG. 12, FIG.
13, FIG. 14, FIG. 15, FIG. 16, FIG. 17, FIG. 18, FIG. 19,
FIG, 20, FIG. 21, and FIG. 22, triple point immersion cell
article 200 includes first cryochamber 212 that having first
cryo-zone 214 and second cryochamber 216 having second
cryo-zone 218. Second cryochamber 216 is nested and
disposed in first cryochamber 212 and is thermally isolated
from exterior environment 224 of triple point immersion cell
article 200 by first cryochamber 212. Third cryochamber
220 includes third cryo-zone 222, and third cryochamber
220 is nested and disposed in second cryochamber 216;
thermally isolated from exterior environment 224 by first
cryochamber 212 and second cryochamber 216; and ther-
mally isolated from first cryochamber 212 by second cryo-
chamber 216. Fourth cryochamber 226 includes fourth cryo-
zone 228 and is nested and disposed in third cryochamber
220; thermally isolated from exterior environment 224 by
first cryochamber 212, second cryochamber 216, and third
cryochamber 220; thermally isolated from second cryo-
chamber 216 by third cryochamber 220; and a triple-point
pressure vessel, fifth and innermost cryo-zone, the triple-
point pressure vessel being: nested and disposed in the
fourth cryochamber; thermally isolated from the exterior
environment by the first cryochamber, the second cryocham-
ber, the third cryochamber, and the fourth cryochamber;
thermally isolated from the third cryochamber by the fourth
cryochamber; and directly accessibie from the exterior envi-
ronment via a thermowell.

In an embodiment, triple point immersion cell article 200
further includes first cryocooler 230 in thermal communi-
cation with first cryochamber 212. Second cryocooler 232 ca

4

be disposed in thermal communication with second cryo-
chamber 216. It is contemplated that first cryo-zone 214 and
second cryo-zone 218 are subjected to closed-cycle refrig-
eration in an absence of a liquid cryogen.

Triple point immersion cell article 200 can include ther-
mowell 284 in thermal communication with first cryo-zone
214, second cryo-zone 218, third cryo-zone 222, and fourth
ceryo-zone 228 and in mechanical communication with first
cryochamber 212, second cryochamber 216, third cryo-
chamber 220, and fourth cryochamber 226.

Vacuum chamber housing 236 is disposed around first
cryochamber 212, second cryochamber 216, third cryo-
chamber 220, fourth cryochamber 226, triple point cell
pressure vessel 234, and thermowell 284. Gas tank 240.1 can

s_ be in fluid communication via gas line 244 with thermowell

284 to provide a heat-exchange gas to thermowell 284, and
gas tank 240.2 can be in fluid communication via gas line
244 and triple-point cell pressure vessel 234 to provide a
condensable portion of the non-metal analyte to triple point
cell interior volume 282. It is contemplated that valves 242.1
and 242.2 can be interposed between portions of gas lines
244.1 and 244.2, respectively, to control flow of gases from
gas tanks 240.1 and 240.2

With reference to FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5,
FIG. 6, FIG. 7, FIG. 8, and FIG. 9, triple point immersion
cell article 200 determines the triple point of non-metallic
analyte 210 in which first cryocooler 230 and second cryo-
cooler 232 are disposed on primary base flange 250.2 that is
disposed on vacuum chamber nipple upper flange 250.3 of
vacuum chamber housing 236.2. Primary base flange 250.2
is a top flange of vacuum chamber housing 236. First
cryocooler 230 and second cryocooler 232 independently
can include: vibration absorbing shock mounts 230.1, 232.1;
vacuum bellows couplings 230.2, 232.2, to both isolate and
dampen any vibrations generated by motors, compressors
and related mechanisms; and thermal straps 230.3, 232.3 to
further mechanically isolate the cryocoolers’ thermal
absorbers and while retaining good thermal coupling to the
first cryochamber 212 and second cryochamber 216. Exem-
plary first cryocooler 230 and second cryocooler 232 include
single-stage Stirling cycle cryocoolers, pulse-tube cryocool-
ers, Gifford-McMahon cycle cryocoolers, and the like.
Moreover, the first cryocooler provides, e.g., at least 15 W
of cooling power near 100 K and the second cryocooler
provides, e.g., at least 5 W of cooling power near 80 K. First
cryocooler 230 and second cryocooler 232 independently
can provide continuous cooling at a temperature from 60 K
down to 300 K or less than 60K. Moreover, the ultimate
achievable base temperature for the second cryochamber can
depends an available cooling power of the second cryo-
cooler; or a cooling power and achievable base temperature
of the first cryocooler as thermally coupled to the first
cryochamber. In an embodiment, first cryocooler 230 and
second cryocooler 232 include independent free-displacer-

5. type single-stage Stirling-cycle cryocoolers.

A demountable service flange 250.1 also is disposed on a
primary base flange 250.2 and is provisioned with vacuum
feed-through ports 276 that provide assembly, disassembly,
and service operations. Service flange 250.1 provides access
ports for gas lines and electrical connections into the interior
of the vacuum chamber housing 236. Vacuum feedthrough
ports 276 can accommodate a multi-pin vacuum feedthrough
unit.

First gas line 268 is received by and fed through service
flange 250.1. First gas line 268 receives the non-metal gas
analyte and communicates the gas analyte from gas tanks
240 into the triple point cell interior volume 282. Gas line


U.S. Patent Dec. 21, 2021 Sheet 11 of 25 US 11,204,288 B2

200 270

236.1

Figure. 11


U.S. Patent

200

Dec. 21, 2021 Sheet 14 of 25
268 270 pee
284.8
am ” 274
F~284.3 268
250.12 274
2 ed 6 ty
268 266 274 : 279 250.32
250.18 te 274
4a 250.10
26S st = 4
on 250.11
250.16
250
212
+L 236.1

See

Figure. 14

US 11,204,288 B2