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Патент USA US2405944

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, Au,
, 1946.
_E. A. EDMoNDs
DIRECT EXPANSION CHILLER
Filed Nov‘. 20, 1945
3mm
vE
zimanzzis'
W
Patented Aug. 20,‘ 1946
2,405,944
UNITED‘ ‘STATES ‘PATENT’. oFi-ucr. _'
DIRECT EXPANSION CHILLER,
Eugene A. Edmonds, Louisville, Ky., assignor to
Henry Vogt Machine Co. Inc., Louisville, Ky.,
a corporation of Kentucky
Application November 20, 1943, Serial No. 5l1§148
4 Claims.
(01. 62-114)
.
2
_
This invention relates to a direct expansion
chiller and proposes a construction in which the
heat exchanging unit comprises a bundle of tubes
larged scale through the left end of one of the
chiller tubes and sight glass;
_
_
Figure 5 is a longitudinal section on an en;
generally connected serially, through which the
larged scale of the right end of one of the chiller
liquid to be cooled flows, and a shell surrounding
the tube bundle constituting the evaporator of
tubes, illustrating the packing for the scraper
a refrigeration system, containing liquid refrig
Figure 6 is ‘a'diagram illustrating the constant
level liquid refrigerant controlled from a single
drive shaft;
'
_
~
erant. ri‘his arrangement avoids the use of stu?
?oat valve;
’
ing glands which seal the ends of the individual
Figure '7 is a diagrammatic view illustrating
refrigerant jackets in chillers of the double pipe 10
the liquid level control of the refrigerant by in
type, and which are subject to leakage of re
frigerant.
.
dependent float valves.
'
>
Referring now in detail to the several ?gures,
One of the objects of the invention is to pro~
the'numerals l and 2 represent direct expansion
vide a chiller of the type described, in which the
tubes are secured adjacent their ends in tube 15 chiller units, each comprising a tube bundle con
sheets which constitute opposite ends of the
chiller, the latter being provided with one or more
expansible zones capable of contracting or ex
panding in the direction of the length of the
sisting of a plurality of spaced parallel tubes 3,
surrounded by a shell ll having the cylindrical
side wall 5 and the end walls 6 and ‘I, said end
walls being tube sheets'through which the tubes
tubes, thereby avoiding stresses, particularly in 20 3 extend, and to which they are secured in fluid.
tight manner, as by welding. For the sake of
the joints between the tubes and tube sheets, and
eiilciency, the tubes 3 extend beyond the respec
between the tube sheets and the surrounding wall
tive tube sheets only far enough to be serially
of the shell, which would otherwise-be produced
interconnected by the transverse connections 8,
through differential thermal expansion between
the tubes and shell.
25 and to receive the end adjuncts which on the
lefthand side of the apparatus, as shown, con~
Another object of the invention is to form the
sist of the sight glass mountings 9, and on the
expansible Zone as a channel with drainage means
opposite side of the apparatus comprise the pack
at the lowermost point so that contaminating oil
ing box for the scraper shafts.
from the refrigerant may collect in the channel
One of the tubes 3, the ?rst in the series, is
and from time to time be discharged.
'
provided. with the inlet coupling ll, while the
Still another object of the invention is the
last tube of the series is provided with the outlet
provision of a direct expansion chiller as de
coupling 12. Where two units are serially inter
scribed, in which the individual tubes are pro
vided with the customary scrapers, driven from
connected, as shown, the outlet 12 of the lower
one endof the apparatus, in which the tubes 35 unit is coupled to the inlet H of the upper unit.
extend beyond the tube sheet at least at the end
Since the inner tube system will ordinarily re
opposite the scraper drive, in a position exposed
ceive a liquid to be cooled while the shell will con
for inspection, each being provided with an end
tain the refrigerant, there is a considerable tem
sight glass through which the end of the scraper
perature differential between the tubes and the
shaft is visible so that breakage of a shaft can 40 wall of the shell which tends to differentially ex
be readily discovered by observing the nonrotat
pand or contract these members. In the absence
ing condition of the end of the broken shaft
of some compensating provision, this would
through the sight glass.
ordinarily create a strain at the joints between
Other objects of the invention will appear as
the tubes and tube sheet and along the joint be
the following description of a preferred and prac 45 tween the tube sheet and shell. To avoid such
tical embodiment thereof proceeds.
‘
strains, the invention provides the cylindrical wall
In the drawing which accompanies and forms
5 with an expansion joint l3 having the form of
a part of the following speci?cation and through
an outwardly extending channeled ?ange of sheet
out the several ?gures of which the same refer
material capable of freely expanding or con
ence characters have been used to. denote iden 50. tracting to compensate for differential elonga
tical parts:
tion between said surrounding wall and the
Figure 1 is a longitudinal vertical section
chiller tubes. Said expansion joint is illustrated
through a chiller of the direct expansion type
as being formed from pressed circumferential
embodying the principles of the invention, two
units being shown serially connected and in 55 members welded together and to adjacent por
' , tions of the surrounding wall 5 between which’
superposed relation;
Figure 2 is an end elevation of the left end of
Figure 1;
.
Figure 3 is an end elevation of the right end of
Figure 1;
-'-"Figure 4 .is a longitudinal section on an'en
itintervenes.
There may, of course, be one or more of these
expansion joints to each unit. Only one for each
unit
is shown in the illustrated embodiment of the
60
invention, and to. provide for the compact posi-j
2,405,944
3
4
tioning of the units, one is shown on the left side
'
journaled in a plate 43, which is pivoted eccen
trically of the axis of said stub shaft at a point
and the other at the right.
‘
The tube bundles are intermediately supported
within the shell by a suitable plate or bracing
M to the support 36 so that the sprocket M can
be tilted towards or away from the driving chain
members, not shown.
38 which it engages.
The plate 43 is provided
Each of the tubes 3 is provided in the customary . . with a threaded pin 45 extending through an
manner with scrapers l 5, each comprising a shaft
l6 with blades ll'supported. thereby and prefer
ably inclined to the axis of said shaft, said blades
‘ 'arcuate slot 46 in the support 36 carrying a nut,
by means of which the plate 43 can be ?xed in
any position of adjustment. The support 33 has
engaging the inner wall of the tube with a scrap 10 an arcuate slot 41, providing play for the stub
ing action which removes deposits from the liquid ,
shaft 42. ,
to be cooled, agitates the liquid to bring all parts
In the embodiment of the invention, as shown,
in which two chiller units are arranged in super
of it into contact with the wall of the tube and
increases the e?iciency of the heat exchange by
posed relation, the liquid level of the refrigerant
in each .unit may be regulated in various ways
familiar to those skilled in the art, two of which
are illustrated in Figures 6 and 7. In the former,
keeping the tube clean. ‘The scraper shaft is__car
ried in bearings 48, and by intermediate bearings,
not shown.
The scraper 3 shaft adjacent the
driven end is provided witha ‘lantern gland l9,
slidably mounted within a cylindrical’ packing
chamber formed in theend closure at. The pack
ing chamber has a restricted innervend wall 2i
for retaining inner packing rings 22 which sur
round the shaft [6 of the scraper. Sufficient of
said ‘packing rings are employed to maintain‘ the
gland in a de?nite zone of the bushing I9, in
which zone said chamber is tapped by a drain 23
for collecting any liquid which may leak past the
inner packing rings. Since the packing may be
an arrangement is shown in which a single ?oat
.
valve controls the level liquidrefrigerant in both
units.
In this form an overflow pipe 4-8 is pro
vided, the upper end of which enters the upper
shell at a point determining the desired liquid
level in said shell, the lower end opening into the
lower shell below the normal liquid level therein.
Liquid refrigerant from a receiver is supplied by
the pipes 49 and 5G to the upper shell, preferably
above the liquid level therein, and ?lls the upper
shell until it over?ows by way of the pipe 48 into
from time to, time compressed to a greater or less ; ; the lower shell, ?lling it to a level determined by
degree, the gland is provided with an ‘exterior so the position of the ?oat in the ?oat chamber 5!,
channel 24 wider than the diameter of the drain
23, so as to remain in registry with said drain re
gardless of longitudinal shift‘ in the position of
the lower part of which is in communication with
the liquid in the lower shell, while the upper part
has a gas equalizing connection with the gas
space in the upper shell. The ?oat controls the
A follower 25 is bolted to the bushing, having a - ’ feed valve 52. When the warm liquid to be cooled,
skirt 26 entering the packing chamber and press
or load, evaporates the refrigerant in the upper
ing against outer packing rings 22', which inter
shell and the liquid level recedes, then the “load”
vene between said follower and gland. The bolts
will be shifted to the lower shell because the warm
have the form of studs 21 screwed into the ?anged
oil will come to the lower shell at a higher tem
end wall of said packing chamber, and having . perature. This increase of load on the lower
nuts which press against said follower and by
shell evaporates the liquid refrigerant in the
which the compression of the packing may from
lower shell. The liquid level ?oat control then
time to time be adjusted.
functions by admitting liquid refrigerant to the
The extended ends of the tubes 3 at the left
upper shell until its over?ows and re?lls the lower
end of the unit have a ?ange collar 28 integrally < shell to the proper refrigerant level. Since the
attached thereto as by welding, and to the collar
liquid to be cooled is warmer when it enters the
2. plate 29 is bolted, which contains the bearin '
upper shell 1 than when it enters the lower shell
38 for the adjacent end of the scraper shaft and
2, the rate of ebullition of the refrigerant in the
has a central recess receiving the sight glass 3!, 3 upper shell will be greater than that in the lower
the latter being retained bysthelbezel 32, which 50 shell, so thatthe level of liquid in the upper 'shell
is removably attached, as by the stud bolts 33.
would at any time be lower than the liquid level
The shaft terminates in a nut 34 which thrusts
in the lower shell. This means that the upper
against the bearing 38, the sight glass being
shell would operate at lower ef?ciency. In order
slightly spaced from the nut by a spacer ring 34’.
to compensate for this greater rate of ebullition
Referring again to the right side of the‘ unit,
in the upper shell, a by-pass pipe 53 is provided
the shafts l6 extend beyond the follower 25 hav
which by-passes liquid refrigerant about the ?oat
ing their ends journaled in bearings 35 carried
controlled valve 52. The by-pass pipe is con
by an upright support 33 mounted upon the ?oor
trolled by a valve 56. This valve may be adjust~
or foundation. Between the follower 25 and
ed to continuously admit a relatively small flow
bearing 35 the shafts [5 are provided with the 60 of refrigerant into the upper shell. The‘ amount
sprockets 3'! disposed in the same vertical plane
of additional liquid refrigerant thus supplied to
and surrounded by a driving chain 38, the" latter
the upper‘ shell may be readily controlled, for if
being driven by a sprocket 35 on an extended por
the valve 54 were opened too far, the result
tion of one of the shafts l5, ‘and which in turn is
would be an increase in level in the upper shell
i the gland due to the compression of the packing.
driven through the chain 30 from a motor, not 65 until the level reached the over?ow, whereupon,
the level in the lower she'll would be raised‘ by‘ the
shown. Since the tubes 3 are connected serially
and the liquid therein flows alternately fromone
over?ow‘, preventing the ,valve 52 from opening
and eventually ?ooding the'apparatus. However,
end to the other of the chiller unit, the chain
drive is so disposed about the‘ sprockets 3‘! as to . the frequency of operation of the ?oat controlled
reverse the direction of drive of the scrapers ‘in 70 valve 52 can readily be determined‘ and the valve
adjacently connected tubes whereby the slight
54 be adjusted’ to prevent over?ow from‘ theup
propulsive effect of the inclined scraper blades
per to the lower shell, due to the continuously
accelerates the ‘?ow of liquid» in each tube‘.
_
added refrigerant.
'
A chain tightener? is provided comprising‘ an
In that form the invention shown in Figure 7,
idler sprocket 41, mounted on a stub shaft? 42 75 liquid refrigerant is independently fed to both
2,405,944.
6
5
the upper and lower shell by way of the branch
pipes 55 and 56 from the main liquid feed pipe
51. Independent float valves 58 and 59 control
the amount of refrigerant fed to each shell, the
respective ?oat chambers having their lower and
upper portions connected to the lower and up
per portions of the respective shells.
It is to be understood that the invention is com
plete in the use of a single unit, also that the ar
rangement of units where a plurality are em
ployed is a matter of choice, the two arrange
ends of said series, a liquid refrigerant inlet com
municating with said shell and a gaseous refriger
ant outlet at the top of said shell.
2. In a direct expansion chiller, a shell com
prising a longitudinal tubular wall and spaced
tube sheets to which said wall is secured, form
ing end closures of said shell, the latter being
the evaporator of a refrigeration system, a plu
rality of spaced tubes passing through said tube
10 sheets and secured thereto with integral sealed
ments herein disclosed being merely by way of
example.
joints, said tubes being serially interconnected
externally of said tube sheets, having a liquid
inlet and outlet respectively at the anterior and
posterior ends of said series, a liquid refrigerant
Each chiller unit is provided with a gaseous
refrigerant outlet 65 at its upper part for con 15 inlet communicating with said ‘shell and a gas
‘eous refrigerant outlet at the top of said shell,
necting to the suction or low side of the refrig
said tubular wall having an integral expansible
eration system. Where a plurality of units are
corrugation extending thereabout, concave on the
combined, gaseous refrigerant outlets may dis
inside of said 'wall and having a drain in its lower
charge into a common stack, not shown, for
multi-pressure operation. A ba?le 6| is prefer 20 portion.
3. In a direct expansion chiller, a shell com
ably mounted within the vshell in the gas space
prising a longitudinaI tubular wall and spaced
therein, in confronting, spaced relation to the
tube sheets to which said wall is secured, form
outlet 60 to prevent liquid refrigerant under con
ing end closures of said shell, the latter being
ditions of ebullition from being drawn oil‘ in the
25 the evaporator of a refrigeration system, a plu
current of evacuating gas.
rality of straight tubes passing through said shell
The construction of a direct expansion chiller
and said tube sheets, extending therebeyond, lat
with a single refrigerant chamber serving a plu
eral connections serially connecting said tubes
rality of tubes in which the tubes are integrally
joined to the tube sheet through which they pass, ' externally of said shell, scraper shafts journaled
and in which the longitudinal shell Wallis formed 80 in bearings in said tubes, terminating within said
tubes at one end of said shell beyond said lat
with an integral expansion joint, is an improve
eral connections and extending beyond said
ment both from the standpoints of simpli?cation
tubes at the opposite end of said shell, driving
and e?iciency, over the conventional double pipe
chiller having a refrigerant jacket individual to
means on the extended ends of said shafts, clo
each tube, in that all packing joints for retaining 35 sures for the ends of said tubes adjacent said
the refrigerant are eliminated, and leakage of
driving means, each closure having means form
refrigerant which is inherent in all packing joints,
ing a cylindrical packing chamber through which
the drive shaft passes, said packing chamber
is avoided.
The location of the ends of the tubes, on that
having a restricted inner end of wall, a lantern
side of the unit remote from the scraper drive, 40 gland through which said shaft passes, interme
in an exposed position and the provision of lat
diately located in said chamber, packing within
eral interconnections between the tubes which
said chamber on both sides of said gland, and an
leave the ends of the latter unobstructed, to
axially adjustable follower extending into the
gether with the provision of the individual sight
outer end of said chamber in compressive rela
glasses forming closures for said ends, permits
tion to said packing, a drain communicating lat
the operative condition of the scrapers to be as
erally with said chamber in the zone of said
certained by mere observation so that a broken
gland, the latter having an external circumfer»
scraper shaft can readily be detected through
ential channel wider than the opening of said
the fact that the observed end is not rotating.
drain whereby said channel remains in registry
In the event of a broken scraper shaft, the af
with said drain, regardless of longitudinal shift
fected scraper mechanism may be readily re
in the position of said gland due to compression
moved by detaching the sprocket at the drive
end, removing the plate 29 which carries the
sight glass and adjacent bearing and withdrawing the entire scraper mechanism through the
end of the tube thus opened.
of the packing.
4. In a direct expansion chiller, a plurality of
units vertically tiered, each comprising a shell
including a longitudinal tubular wall and spaced
tube sheets to which said wall is secured form
ing end closures of said shell, the latter being the
evaporator of a refrigeration system, a plurality
While I have in the above described what I
believe to be a preferred and practical embodi~
ment of my invention, it will be understood to
of spaced tubes passing substantially horizontally
those skilled in the art that the speci?c details 60
through
said tube sheets and secured thereto with
of construction and arrangement of parts are by
integral sealed joints, said tubes of each unit
being serially interconnected externally of said
way of illustration and not to be construed as
limiting the scope of the invention as de?ned in
the appended claims.
What I claim as my invention is:
1. In a direct expansion chiller, a shell com
tube sheets, having a liquid inlet and outlet re
65 spectively at the anterior and posterior ends of
prising a longitudinal tubular wall and spaced
tube sheets to which said wall is secured, form
ing end closures of said shell, the latter being the
evaporator of a refrigeration system, a plurality
of spaced tubes passing through said tube sheets
and secured thereto with integral sealed joints,
said tubes being serially interconnected exter~
nally of said tube sheets, having a liquid inlet and
outlet respectively at the anterior and posterior 75
said series, a conduit for supplying liquid refrig
erant to the uppermost unit, a float valve re~
sponsive to liquid level in the lowermost unit
controlling primary admission of liquid refriger
ant to said uppermost unit, and an over?ow con
duit from a point in the uppermost unit deter
mining the normal liquid refrigerant level
therein, to the lower unit.
EUGENE A. EDMONDS.
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