Feb- 12, 1952
R. |_. BRUNSING
THERMOMETER AND METHOD OF DETERMINING
TEMPERATURE IN A VACUUM COOLING
CHAMBER FOR COOLING VEGETABLES
2,585,086
Filed'Feb. 14, 1950
INVENTOR.
/Pz'x z. z/Pu/xsf/mv
4170190276‘
Patented Feb. 12, 1952
2,585,086
UNITED STATES PATENT. ‘OFFICE .~
THERMOMETER ‘AND METHOD ‘OFKDETERF,
MINING TEMPERATURE ‘IN A VACUUM
COOLING CHAMBER FOR COOLING VEGE
TABLES
Rex L.. Brunsing, San Francisco, Calif, assignor
toVacuumv Cooling Company, San Francisco,
Calif., a corporation of Nevada
Application February 14, 1950, Serial No. 144,186
9 Claims. (01. '62—1'52)
1
2
Fig. 2 is: a'sidet-elevatlonalview of the tem
This invention relates tora “thermometer or
temperature control means for indicating the
v"temperature within-a body ‘of vegetables in a
"vacuum cooling chamber.
perature control unit or‘. bulb.
Fig.~ 3 is a sectional view‘ taken along line 3
' of Fig. 2.
Certain types of ‘vegetables; such, for example, '
>
'
In detail, the vacuum tube is indicated ‘at.’ I,
. and may be provided with gates 2, 3 at its oppo
as .lettuce, cabbage, etc., when .preecooled by
site ends for loading produce, such as. lettuce,
placing them in a vacuum chamber and evapo
.into the tube at one end and for withdrawal of
- rating ‘surface moisturetrom within the‘ heads,
the-produce from theopposite end. ~Suchlettuce
present . problems-‘that have heretofore retarded
the use of the vacuum ‘cooling system because 10 may be in crates 4 (indicated in dotted-lines)‘ that
are on cars or trucks-5 mounted on tracked; that
"'no' dependable :method was known for :uniformly
extend from end toend of the tube. ‘Loading
and unloading platforms or tracks (not shown)
may-extend to and from opposite ends of tracks
lowering ' the?temperaturev throughoutv the heads
" to“ substantially‘ 329. F.
.’In my copendingxapplicationiSerial No. 144,185,
v?led Febrnary14, 1950,..I. have shownia method
.~ Bat opposite ends of the tube. ' The tube iscon
"for ‘satisfactorily. lowering the temperature. . The
'nected with a P1138101’ conduit 1 that .is in turn
connected with any suitable means (not, shown)
.for reducing the pressure within the tube‘l to
"method shown in said vapplication requires
‘thrusting the pressure :type ‘thermometer be
‘“tween .headsof lettuce, which’operation some
. shippers‘dislike‘becauserof. the possibility of mu
~tilatingfthe outer leaves’of one-or more-heads
of lettuce. Also, while said method is satis
factory where the ‘produceis loaded intoithe
'say'about- an inch of mercury.
20
-
-
Conventional valve means anywhere-in tube
I or conduit 1 may be provided for breaking the
. vacuum and. for admitting - atmospheric air; "into
"the tube ‘for-equalizing: the pressure therein with
atmospheric pressure.
vacuum chamber or tube through one end thereof
The present invention is concerned with the
".and is unloaded from the same end, it ‘is not; r 25
means to enable an operatoroutside the tube
‘convenient where the produce is loaded. .into one
' to know the temperature within the body otpro
end of .the vacuum tubes-and is unloaded from
iduce and especially between heads of lettuce in
' the oppositeend.
.
Attempts to solve the I problem .iby using ‘the
the crates without. ‘having to place a ‘thermom
conventional "wet bulb thermometers ~were"lun- r.1a eter between said heads. It might :be here stated
. that a conventional wet bulb thermometer placed
“successful, and equally‘ unsuccessful were at
within’ the tube I does not accurately-give this
“tempts to'use any: of the conventional thermom
eters in the chambercutside the load of‘ produce.
temperature. nor would a thermometerof any
.One of the‘ main objects of. thepresent inven
kind merely placed within the tube outside-the
‘body of produce.
tion is the :provision .of :a. thermometer that .may
The thermometer of this invention comprisesv a
irberplaced' within. the ‘vacuum. chamber at: apoint
' conventional :pressure type thermometer ‘having
‘outside the load ofcproduce to? be cooled,.v and
an elongated hollow body I0 that contains-a
which thermometer will closely follovwthetram
‘?uid, usually gas," and which body. is connected
perature variations that occur betweenirheads
1st .l'ettuce','iwhere it ‘is. essential to know the exact 1 40 at onelend bya pipe or tube H (Fig.2)vwith-a
: temperature.
Bourdon gauge I2 (Fig. 1), or the equivalent,
: outside the tube I, for registering the tempera
.Another'object "of' the invention ‘is the :pro
ture at the body I. This pipe- II is usually, an
' vision of means'within. a vacuum tube'or vacuum
armored tube and in the present instance it con
‘cooling chamber that ‘need not be moved or
‘changed, and that will quickly .andv accurately: 45 nects’ with .a coupling that extends air. tight
. follow temperature variations in the chamber in
wthrougha wall of the. tube l,. which couplingzis
in‘ turn connected with the‘gauge I2.
vthe exact place inaload of producein said cham
her. that is essential to the proper cooling of :said
The body I 0 is normally horizontal,v and spaced
. produce-without freezing the same or. any: part
above the same, and-parallel- therewith, is axtube
I3 that is parallel with body I. One end oftube
Other' objects and advantages will- appear in
I3’ :is .closed and the .opposite‘end ‘is' connected
the description: and in the claims.
by an extension M of said tube with a source ‘of
. In the drawings,-Fig. 1 is a semi-diagrammatic
water I5 under pressure from outside: the vacuum
.side view of a vacuum cooling tube with the pres
:..chamber. This tube iii-extends air tight through
ent invention indicatedtherein.
‘5- a. wall of the vacuum‘chamber and any suitable
thereof.
.
>
2,585,086
3
At this point, where headed let
tuce is being cooled, the operator will stop fur
7 temperature.
control valve I6 may be in said tube outside said
vacuum chamber between said tube and said
source. The source of water may be ordinary
ther evacuation of air from the chamber, but the
latter will stay closed. The temperature within
tap water that is at substantially atmospheric
temperature, which would substantially corre Or the chamber will continue to drop, and evapora
tion of moisture from the wicking will continue
spond with the temperature of the lettuce heads
until the thermometer registers 32° F, when the
operator will open the chamber to the atmos
phere and further cooling will cease.
before they are pre-cooled. This water is under
pressure and the ?ow may be controlled by valve
I 6, although the thermometer structure itself in
cludes a control feature, as will later be ex
plained.
Wicking material I8 encloses the tube I3 and
the body I0 of the thermometer from end to end,
10
By the present thermometer assembly it has
been discovered that the temperature registered
by the thermometer will so exactly follow the
- temperature that exists between the heads of let
tuce in the load as accurate as though the ther
such as the conventional tubular wick used in 15 mometer itself, apart from the wicking and wa
ter supply, were positioned between the heads as
lamps, thus providing a uniform layer around
described in my copending application. Hence,
the tube and thermometer. The wicking I8 ex
in those instances when it is impractical or unde
tends between the tube I3 and body In to provide
sirable to follow the procedure mentioned in my
a web I9 (Fig. 3). By making the wicking I8 in
this wicking preferably being of the woven type,
the form of a fairly large tube and inserting the 20 said copending application, the present appara
body I 0 within the same at one side and the tube
I3 at the opposite side and then drawing the
’ tus is substantially as ei?cient in giving the de
sired temperature.
It is also pertinent to note that in the present
wicking tightly about the said body and tube by
case, the lettuce is not torn or multilated by
bringing the wicking together between them, the
preferred type of structure is formed since the 25 thrusting the thermometer into a crate of lettuce.
The thermometer is preferably positioned out of
wicking is of uniform weave, and thickness
the flow of moisture vapor from the lettuce to the
throughout.
exhaust conduit, inasmuch as greater accuracy
Pressure plates 20, 2I (Figs. 2, 3) comprising
can be obtained where the thermometer is adja
elongated metal strips held the web I9 flat be
tween them, and one longitudinally extending 30 cent an end of the vacuum chamber.
The wicking is saturated with water supplied
marginal portion 22 of each plate is curved to
from a source at atmospheric room temperature,
partially extend around opposite sides of tube I3
the length of the latter.
Bolts 23 extending
through the plates 20, 2| at spaced points there
which may normally be about 70° F., and is kept
saturated throughout the evaporation step. Ob
along are provided with wing nuts 24 to enable‘ 35 viously under similar circumstances, the conven
tional wet bulb wick would freeze. This feed of
the operation to vary the pressure of the plates
water to the thermometer is vfast enough under
on the web I9 as desired.
the conditions herein described to prevent sub
Where the Wicking extends around the body It
stantial interior cooling of the‘water in the water
of the pressure thermometer it is fully exposed
for evaporation of moisture, and the wickingl 40 supply tube. As soon as the vacuum is broken,
and atmospheric air is admitted to the chamber,
along the upper half of tube I3 is also so exposed.
the thermometer will be ‘almost immediately
This tube I 3 is provided with a row of small open
warmed by the supply of relatively warm water
ings 25 that open into the portion of the wick
to thus re?ect the elevated temperature.
that is covered by a pressure plate. Normally
The loading and unloading of the vacuum
one row of such openings is found to be adequate, 45
chamber may be very fast due to the present
although the position of the openings may be
system, and the thermometer will follow tem
staggered so that a substantial equal number
perature changes in the chamber as fast as they
open into the wicking along opposite sides of a
occur. There is no material “lag.”
plane extending longitudinally of the web and
In the case of soft, puffy heads of lettuce,
coplanar with said web.
spinach, etc., the vacuum may be maintained
Any suitable bracket members 26 may be pro
constant and the moisture vapor continuously
vided for securing the thermometer assembly
removed, until the thermometer registers 32° F.,
horizontally within the vacuum chamber with
and then the vacuum may be broken at once and
said tube I3 uppermost. When so supported
within the vacuum chamber the assembly is out 55 atmospheric pressure restored within the vacu
um chamber. The cessation of evacuation need
of the way of produce that is loaded into ‘the
occur only where tightly headed vegetables are
chamber and that is withdrawn therefrom. The
operator does not manipulate said assembly.
When the vacuum chamber is closed with a
load of produce therein, such as lettuce or the
like, the gauge I2 will register substantially the
same temperature as that of the lettuce. As soon
as the air is evacuated from the chamber, evap
oration of moisture from the wicking I8 and from
the lettuce will be accelerated and the gauge will
commence to show a progressive decrease. All
being cooled.
I claim:
‘
'
'
1. The method of causing a thermometer to
follow the temperature variations within a body
of leaf vegetables in a vacuum cooling system and
which vegetables have vaporizable surface mois
ture thereon that comprises the steps of placing
said thermometer and said body of vegetables
within an enclosed space and in spaced relation
this time tap water, or water at substantially
therein, withdrawing air from within said space
atmospheric temperature will be supplied to tube
I3 at a rate of speed to constantly replenish the
to cause evaporation of said moisture and con
sequent cooling of said vegetables, and simul
water being evaporated from the wicking. The 70 taneously enclosing said thermometer within a
temperature within the chamber will continue to
thin layer of water in heat transfer relationship
thereto and with said layersubjected to the in
?uence of the reduced air pressure within said
duced temperature of say 35“ F. it has been found
space, continuously conducting water from out
that the temperature between the lettuce heads
or in the outer leaves will actually be‘. the same 76 side said space through said space and to said
be lowered and when the gauge indicates a re
2,585,086
thermometer at=a~rateofvspeed sufficient to
maintain said ?lm substantiallyconstant.
6. TA temperatureiindicator for'userln aevacunm
" cooling system. withinv a "vacuumzchambersvzcom
» 2. The method of causing asthermometer to
follow the temperature variationswithin a body
of leaf vegetables in a vacuum cooling systemv
and which vegetables have. vaporizablev surface
moisture thereon that comprises the-steps of
placing said thermometer and said body ofvege
tables withinan enclosed‘. space and in spaced
relation therein, withdrawing air from within;
. said space to‘ cause evaporation of said moisture
" and consequent‘ cooling of ‘said-vegetables," and
simultaneously
enclosing
said
thermometer
within a thin layer of water in heat transfer
relationship thereto and with said layer subjected
to the in?uence of the reduced air pressure within
said space, continuously conducting water from
outside said space through said space and to said
thermometer at a rate of speed sufficient to maine
tain said ?lm substantially constant, and free
from an excess of moisture above the amount of
said layer.
3. The method of causing a thermometer to
follow the temperature variations within a body
of leaf vegetables in a vacuum cooling system
and which vegetables have vaporizable surface
moisture thereon that comprises the steps of
prising, an elongated. pressure thermometer ‘for
"a' fluid,v a ‘tube extending 'alongsidevs‘aid" ther
mometer in spaced relation thereto formed-with
a plurality‘ of relatively small apertures .for .dis
‘charge of ‘liquid therefrom, .said'tube being :closed
atone end and provided'withm'eans:atiitsroppo
site end for connecting the same with a source
of liquid'for supplying liquid thereto, wicking
material enclosing said thermometer and said
tube and providing a web between said thermom
eter and said tube for conducting liquid from
said tube to said thermometer, a pair of opposed
plates disposed between said tube and said ther
mometer spacing said tube from said thermom
eter and clamping said web under pressure be
tween said plates and means for varying the
pressure of said plates on said web for controlling
20 the rate of ?ow of liquid through said Web.
7. A temperature indicator for use in a vac
uum cooling system within a vacuum chamber
comprising, an elongated pressure thermometer
for a ?uid, a tube extending alongside said ther
mometer in spaced relation thereto formed with
a plurality of relatively small apertures for dis
charge of liquid therefrom, said tube being closed
at one end and provided with means at its op
placing said thermometer and said body of vege
posite end for connecting the same with a source
tables within an enclosed space and in spaced
relation therein, withdrawing air. from within 30 of liquid for supplying liquid thereto, wicking
material enclosing said thermometer and said
said space to cause evaporation of said moisture
tube and providing a web between said ther
and consequent cooling of said vegetables, and
mometer and said tube for conducting liquid
simultaneously enclosing said thermometer with
from said tube to said thermometer, a pair of
in a thin layer of water in heat transfer relation
ship thereto and with said layer subjected to the 5-‘ opposed plates disposed between said tube and
said thermometer, a pair of opposed plates dis
in?uence of the reduced air pressure within said
posed between said tube and said thermometer
space, continuously conducting water from out
spacing ‘said tube from said thermometer and
side said space through said space and to said
clamping said web under pressure between said
thermometer at a rate of speed su?icient to main
plates and means for varying the pressure of
tain said ?lm substantially constant, said water
said plates on said web for controlling the rate
being supplied to within said space at substan
of flow of liquid through said web, said plates
tially atmospheric temperature.
being formed with extensions partially extending
4. In combination with a vacuum tube adapted
around said thermometer with the said wick
to contain vegetables for cooling the same, a
ing material between said extensions and said
temperature recording instrument comprising a
thermometer, and means for supporting said
thermometer and a conduit for a liquid in side
thermometer and said tube horizontally with
by side spaced relationship within said vacuum
in said chamber with said tube above said ther
tube, a moisture conductor of ?brous material
mometer.
enclosing said thermometer and said conduit and
8. In combination with a vacuum tube adapted
disposed between said thermometer and said con 50
to contain vegetables for cooling the latter, a
duit for conducting moisture from said conduit
thermometer supported within said tube, a layer
to said thermometer, openings formed in said
of moisture absorbent, moisture conductive ma
conduit for ejecting liquid therefrom to said con
terial enclosing said thermometer, a conduit
ductor, means for supplying liquid to said conduit
from outside said tube, a temperature indicator 55 connected with a source of water outside said
tube and extending into said tube to said layer
outside said tube and means connecting said
for conducting water from said source to said
thermometer with said indicator for indicating
layer, said conduit being apertured at said layer
the temperature at said thermometer, means for .
for discharge of water therefrom to said layer,
controlling the rate of flow of liquid through said
wicking material from said conduit to said ther-‘ 60 a temperature indicator outside said tube con
nected with said thermometer for indicating out
mometer.
~
side said tube the temperature at said indicator.
5. A temperature indicator for use in a vacuum
cooling system within a vacuum chamber com
prising, an elongated pressure thermometer for a
9. In combination with a vacuum tube adapted
to contain vegetables for cooling the latter, a
fluid, a tube extending alongside said thermom 65 thermometer supported within said tube, a layer
of moisture absorbent, moisture conductive ma
eter in‘spaced relation thereto formed with a
plurality‘ of relatively small apertures for dis
terial enclosing said thermometer, a conduit
connected with a source of water outside said
charge of liquid therefrom, said tube being closed
tube at substantially tap water temperature and
at one end and provided with means at its oppo
site end for connecting the same with a source 70 extending into said tube to said layer for con
ducting water from said source to‘said layer,
of liquid for supplying liquid thereto, wieking
said conduit being apertured at said layer for
material enclosing said thermometer and said
discharge of water therefrom to said layer, a
tube and providing a web between said thermom
temperature indicator outside said tube con
eter and said tube for conducting liquid from
75 nected with said thermometer for indicating
said tube to said thermometer.
2,585,086
7
."outside' said tube the temperature at said in-
dicator' 3' Suction conduit opening into the up‘
per side 01' said tube for withdrawing air and
8
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'
REFERENCES CITED
The following references are of record in the
me of this patent;
the evaporated moisture from within said tube,
,
and means for supporting said thermometer
UNITED STATES PATENTS
within the upper portion of said tube spaced 0 Number
Name
Date
from said suction conduit so as to be out of the
1,404,400
Moon ____________ __ Jan. 24, 1922
direct ?ow of air into said suction conduit.
2,494,769
Mabey ___________ __ Jan. 17, 1950
FOREIGN PATENTS
REX L. BRUNSING.
‘ 10 Number
389,535
w
Country
Date
Great Britain ____ __ Mar. 23, 1933