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Патент USA US2136114

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Nov. s, 1938.
A. A. MARKSON .
2,136,114
CONTROL SYSTEM FOR STEAM REFRIGERATING SYSTEMS
Filed Feb. ll, 1955
INVENTOR
W
2,136,114
~ Patented Nov. 8, 1938
UNITED STATES
PATENT OFFICE `
2,136,114
CONTROL SYSTEM FOR STEAM REFRIGER
ATING SYSTEMS
Alfred A. Markson, Kew Gardens, N. Y., assignor
to John M. Hopwood, Dormont, Pa.
Application February 11, 1935, Serial No. 6,053
5 Claims. (C'l. (i2-_152)
_
This invention relates to refrigerating systems
of the type in which the refrigerant or the ma
terial to be cooled, for example water, is cooled
in a'. tank which is maintained under partial
vacuum‘by means of a steam actuated vacuum
>device such asa venturi or evactor, and more
particularly to a control system for maintaining
the proper relationship between the steam pres
sure and the pressure in the flash tank or
1° evaporator and a condenser into which steam,
Aair, and water vapor are discharged.
In refrigerating systems of this type, whether
they be used for air conditioning or for pro
viding a supply of cool water for oflice buildings,
'l5 and the like, the water being cooled which, for
convenience will be called refrigerant herein,
is delivered from a source of _supply into a flash
tank or vacuum chamber in which it is cooled
and from which the cooled water is‘circulated
V$50 to Wherever needed. A booster or steam jet com
pressor venturi or evactor type is connected to
the flash tank and to a water cooled condenser
and a supply of steam is provided which when
passed through the booster at high velocity picks
25 up'vapor which is evaporated in the flash tank,
compresses and transfers it to the condenser.
As' the vacuum increases the boiling point of the
water is lowered, so that some of the water is
the flash tank to the condenser, while the dif
ferential would tend to increase because of the
increased load on the condenser.
'
Ifgtherefore, the steam pressure at the nozzles
is regulated or controlled to bear a deñnite'rela
tionship to the differential between the flash tank
and condenser pressures, decided economies in
the amount of steam and condenser cooling water
employed may be realized.
An object of this invention is the provision of
a regulating systemv which‘will respond to changes
in the difference between the flash tank and
condenser pressure, hereinafter called the pres
sure differential, and so control the pressure.
of ‘the steam at the'nozzles tha‘t a deûnite rela
tionship is maintained between the nozzle steam
pressure and said pressure differential.
Another object is the provision of a regulating
system which will respond to changes or varia-I
tions in a given pressure differential to control 20
the pressure of the steam at the nozzles in
such fashion as to maintain a definite relation
ship between the nozzle steam pressure and the
pressure differential regardless of the number of .`
25
boosters or nozzles that may be operating.
Other objects of the invention will, in part, be
apparent and will, in part, be obvious from the
following description taken in conjunction with
vaporized by the heat of the liquid, whereby the
the accompanying drawing, in which:
`
cooler the temperature of the liquid will be. For
a control system embodying one form of the
invention, parts of the apparatus of the sys
Figure l is a more or less diagrammatic view
temperature of the remaining liquid is released. of a steaní refrigerating system provided with
-The higher the vacuum in the iiash tank the
example, if the pressure in the flash tank is re
duced to a value say 0.2575 inch of mercury ab
tems being shown insection;
"eo
‘
Fig. 2 is a. fragmentary view in section of a 35
35 solute pressure, the temperature of the water'inv f portionof a regulator embodied in the control
the tank will be about 41° F.
»I
In systems of this type, one or more boosters or
steam jet compressors are employed and are con
nected in multiple to a steam supply header. 'I‘he
y number of boosters employed at any `one time
is dependent upon the refrigerating load. Each
booster- or compressor may include one or a
group of nozzles, and the steam in passing
through them is converted from pressure head
. into velocity head which is high enough to over
come the back pressure in the condenser and to
compress and transfer air and water vapor from
thaï flash tank to the condenser.
_
system;
.
Fig. 3 is a view in 'vertical section of an escape
ment valve associated with the regulator; and
Fig. 4 is afragmentary view in side elevation 40
of the flash tank showing a plurality of steam
jet boosters or ebmpressors connected to a com
mon header in which the steam pressure is regu
lated- by one- regulator.
.
'I'hroughout the drawing and the `specification,
In Fig. 1 of the drawing, a flash tank or
vacuum chamber I is illustrated in which the
rPhe steam flow through a nozzle is theoreti
f‘ cally a function ofv the absolute nozzle pressure
while the vapor flow from the ilashtank to the
liquid, _such as water, is refrigerated. Thewater
or liquid to be cooled is introduced into the iiash
tank by a pipe 2 having sprays 3 extending from
condenser is a function of the difference between
the pressure in the flash tank and in the con
discharges into the tank. The cooled or chilled
denser'. When this differential is at the proper
value and the nozzle pressure is at its eiiicient
operating point, any increase in steam pressure
.above that required to maintain the proper pres
sure differential between the flash tank and the
condenser will not effect any material increase
l in the rate of transfer or vapor and air from
45
like ref_erence characters indicate like parts.
opposite sides thereof and from which the water `
liquid or water is discharged into a cooling sys-.`
tem,- not shown, by means of- a pump 4. The 55
water in the flash tank is chilled or cooled by
maintaining a partial vacuum therein, the .de
gree of vacuum depending uponl the temperature
of liquid desired. The vacuum is maintained by
vmeans of one or'more steam jet compressors "
2
2,186,114
or boosters 5 connected to the top of the flash
tank and to the top of a water cooled condenser
6. Cooling water for condensing the steam is
delivered to the condenser through an inlet
pipe ‘I and is discharged therefrom through an
outlet 8. The air and water vapor in the con
denser is exhausted by means of a vacuum pump
9, and the condensate is discharged therefrom
acteristics of the booster or compressor, while
by means of a pump Iii'.
10
excess heat is put into the cooling Water unneces
The steam jet compressors or boosters 5 are,
sarily because of the excess steam employed. If
the pressure of the steam at the nozzles were
controlled in accordance with the pressure dif
ierential existing between the flash tank and the
condenser, considerable economies in the use of
steam may be attained. Theoretically, the ñow
as stated previously herein, operated by steam
which is delivered thereto by means of a plu
rality of steam nozzles II. Each booster may
have one -or a. plurality of nozzles Il, which
always function as a group, but the number of
boosters in operation at any one time is de
pendent on the load and these may be turned
of steam through a nozzle is a function of the
absolute nozzle pressure, While the flow of vapor
“on” or “olf” manually or automatically in ac
cordance with the load requirements.
through the booster is a function of the diiîer
Steam is'
ence in pressure between the condenser and the
20 supplied to the boosters from a supply pipe or
ñash tank when the evactor is working at its 20
header I2, and the pressure of the steam at the
nozzles of these boosters is controlled by means
of regulator I3. This regulator is illustrated as
most eñicient point.
with the value oi' steam pressure required.
The steam, in passing through the nozzles of
the booster or boosters is converted from pres
sure head into velocity head, which creates a_
and eifects the transfer of air and water vapor
from the iiash tank to the condenser. If the tem
perature of the Water is to be maintained at 41°
F., for example, then the absolute pressure in
35 the iiash tank is maintained at about 0.2575 inch
of mercury. The action of the steam jet com
pressors or boosters and the steam nozzles em
ployed for creating and'maintaining the desired
vacuum in the flash tank is well understood in
40 this art and for that reason no further descrip
tion thereof is believed necessary.
The control system of this invention is de
signed primarily to secure economy in the use
I of steam by regulating the steam pressure in ac
cordance with the pressure differential between
the ilash tank and condenser. -The function of
the evactor is to transfer water vapor and air
from the ñash tank to the condenser at such a
rate as to maintain the proper degree of vac
50 uum in the flash tank. In accomplishing this
transfer, the evactor must work against a pres
sure head which is equal to the diiference, in
absolute pressure, between the flash tank andcondenser pressures. The absolute pressure in'
55 the flash tank will vary only with variations in
the temperature
pressure in the
amount of steam
tity of available
60
of the chilled water, while the
condenser will vary with the
being condensed and the q'uan
cooling water and its temper
ature.
r
If the condenser water is cooled by a cooling
tower (not shown) considerable variations may
be expected in the condenser pressure. When
the outside wet and dry bulb conditions are high,
the refrigeration load will be high and the cool
ing water for the condenser lwill be warm. Under
these conditions the maximum pressure differ
ence between the iiash tank and the condenser
will exist. As the outside wet and dry bulb con
70 ditions become lower, the refrigeration require
ments become less with the result that the cool
ing water for the condenser will be colder; Thus
less pressure difference exists between the ñash
tank and the condenser under low outside wet
and dry bulb conditions.
'
In accordance with this invention, control ap
paratus is provided which will maintain a defi
nite relationship between the pressure diiîeren
comprising a valve I4 and a pressure actuated
25 device I5 for adjusting the valve in accordance
30 vacuum and lowers the pressure in the iiash tank
If the steam pressure at nozzles II is higher
than that required to transfer the vapor and
air from the iiash tank to the condenser at a
rate which will maintain the required pressure
difference between the ñash tank and the con el
denser, no material increase in the amount of
vapor transferred is eiïected because of the char
tial existing between the ñash tank and con- ~
denser and the pressure oi' the steam at the
nozzles, thereby avoiding the use of excess steam
to accomplish the work involved. The capacity
of the refrigerating system would be adjusted by
changing the number of boosters or compressors 30
employed at any one time either by hand or
automatically, without in any way interfering
with the operation of the control system in main
taining the above stated relationship between the
nozzle steam pressure and the pressure differen
35
tial between the flash tank and condenser.
The apparatus embodied in the control system
comprises a regulator I 1 which is responsive to
the pressure in the condenser and in the iiash
tank and to the steam pressure at the~nozzles
and causes regulating device I3 to operate in 40
such fashion that the' steam pressure at the
nozzles will be caused to bear a definite relation
ship to the differential between the flash tank
and the condenser pressure.
The steam actuating device I5 comprises a 45
pressure-tight housing I8 having therein a ilexi
ble member I9, such as a bellows, which carries
a thrust plate 20 at its upper end. The- thrust
plate when it is in' its uppermost position engages
spaced lugs 2I on the top of housing I8 so that
actuating pressure when admitted to the hous
ing will compress the bellows and move the thrust
plate downwardly. A boss 22 centrally positioned
on the lower side of plate 20 is coupled to stem
23 of valve I3 by means of a push rod 24 and 55
adjustable couplings 25.
These couplings pro
vide a means for adjusting the valve in relation
to the limits of travel of the bellows. The lower
limit of travel of thrust plate 20 is ñxed by a
tubular stop 26 which is threaded on boss 22 to 60
provide adjustment in the downward movement
of the plate. Movement of the bellows is resisted
by a coll spring 21 located between the thrust
plate and the bottom- of housing I5. The coil
spring urges the plate and valve stem upwardly 65
and tends to actuate valve I4 to a position of
minimum opening, in which case minimum steam
pressure exists at nozzles II. As the pressure of
actuating medium delivered to housing I 8 in 70
creases the thrust plate moves- downwardly
thereby moving thel valve stem towards open
vposition and increasing the pressure of the steam
nozzles.
‘
The operating medium for actuating device I5
3
2,136,114
may be compressed air taken from a supply pipe
28 in which the pressure is substantially constant,
and transmitted thereto by -regulator I1 at varying
pressures depending upon the relation between
the nozzle steam pressure and the pressure dif
ferential between the flask tank and condenser.
Regulator I1 need not be of any special con
struction, as any regulator which will provide
stability in the relationship between the nozzle
steam pressure and the flash tank-condenser
pressure differential will serve the purpose. The
illustrated embodiment of regulator I1 is pre
ferred, but as novel features of this regulator per
that is, up or down as seen in the drawing. This
gradient diminishes from the maximum value it
exerts at the beginning of movement of the dia
phragm to zero value and at a rate which allows
suñicient time `to elapse to effect the necessary;`
adjustment in the steam pressure called for by a
change in the pressure differential between the
flash tank and condenser `or as effected by a
change in steam pressure without a change in the
pressure differential, as where the number of noz
zles II in use is changed to suit a change in load ` '
on the refrigerating system.
l
se are disclosed and claimed in a copending ap
15 plication of Robert R. Donaldson, Jr., Serial No.
14,468 filed April 3, 1935, and assigned to John M.
’ Hopwood, no claim thereto is made herein.
Regulator l1 comprises an escapement valve 3D
(see Fig. 3)_ which controls or determines, by its
position in a valve body 3|, the pressure of the air
delivered through a pipe 3|' to device I5;. a dia
phragm 32 disposed in a housing 33 which responds
to the difference in pressure between the flash
tank and condenser; a steam pressure responsive
device 34; and a lever 35 fulcrumed on a roller'36
and operatively connected, at one end and on one
side of the fulcrum by a link 35’ to device 34 and
on the other side of the fulcrum to the pressure
differential responsive diaphragm 32. Thus the
30 escapement valve 30 is under the joint control of
the pressure differential responsive diaphragm
and to the steam pressure responsive device 34
The dash-pot comprises a coil spring 41 which
is connected at its upper end to the pressure dif
ferential responsive diaphragm and at _its lower 15
end to a piston 48 disposed in a vertically extend
ing cylinder 49. The upper end of the cylinder
is open to the atmosphere and the lower end is
connected to a chamber 50 formed by a flexible
member such as a bellows.
The bellows is en
20
closed in a pressure _tight housing 5I to which air
pressureis .admitted by a pipe 52 at pressures
determined and controlled by valve 30. The lower
end of the) bellows is closed by a thrust plate 53
which in its lowermost position is spaced from the 25
bottom of the housing by“ lugs 54 to allow the air
pressure to work properly on the bellows. A com
pression spring 55 located inside the bellows yield
ingly opposes contraction of the bellows and pro
vides a positive gradient against which the air 30
pressure must work.
Housing 5I is carried by a frame 56 which sup
ports the diaphragm housing and the aforemen
so that the steam pressure at nozzles II will be ' tioned parts above it, and the housing also car-'
controlled and adjusted in accordance with the
pressure differential between the flash tank and'
condenser.
As will be disclosed later herein,.the range of
steam pressures which will balance a correspond
ing range of pressure differentials between the
ries a bracket 51 onl which a steam pressure re
flash tank and condenser may be changed by ad-
tom of the cylinder is connected by pipe 58 which
is connected at its -top with the interior of cylin
justing the position of fulcrum 36 with respect to
link 35’.
In order that the weight of lever 35 may not
affect the operation of the diaphragm 32 and de
vice 34 in their responses to the flash tank and
condenser pressure differential and the steam
pressure, respectively, a relatively light spring 39
35
sponsive device 34 and the fulcrum 36 are sup
ported.
»
-
I
The space in cylinder 49 above and below piston
48 and the space within bellows 50 are ñlled with
a non-compressible fluid such as pil and the bot
der 49 at a point above the piston, at a height
above the uppermost limit of travel of the piston.
The pipe 58 is provided with a needle valve 59 that 45
fixes the rate, for a given oil pressure, at which
oil may ñow from the space below the piston to
the space above it, or -vice versa, in case either
- is connected at one end to lever 35 at a suitable
the bellows contracts or expands, respectively, or
point between fulcrum 36 and the connection be
in case the piston is moved downwardly or up
tween valve 30 and the diaphragm 32, and at its
opposite end to an anchor 40 which is supported
by an adjustment screw 4.I from a support hous
ing 42 carried by a frame 43 on which valve 30
'and body 3| are supported. This spring is ad
justed to carry the unbalanced weight of lever 35
and maintain it in operating engagement with the
wardly, respectively, by the diaphragm 32.
If diaphragm 32 moves downwardly in re-I
sponse to an increase in the pressure differential
between the >flash tank and the evactor, spring
41 is compressed and opposes such movement of
the diaphragm but the spring compression tends
valve and diaphragm connection. The opposite
to move the piston 48 downwardly at a rate fixed
by the rate at which the oil can flow from the
end of the lever is connected to an adjustable
space below the piston to the needle valve to the
tension spring 44 which fixes the loading that de- ì space above it. As the piston moves downwardly 60
7,0
vice 34 operates under and provides a means for the restraint offered by the spring tends to dimin
initially adjusting the steam pressure at nozzles ' ish but, while this restraint is diminishing, valve
I I to the proper value for a given flash tank and 30 is being opened to deliver air at increasing
condenser pressure differential. Regulator I1 is pressure to device I5 and to the interior of hous 65
in equilibrium at these values of pressure dif .ing 5I, thereby increasing the steam pressureat
ferential and steam pressure, and thereafter the the nozzles 1, because valve I4 has been opened
regulator will automatically adjust the steam wider, and increasing the pressure acting-on the
pressure so that the regulator will always be in dash-pot bellows 58. Bellows 50 therefore con
tracts an amount proportional to the pressure ex
balance for different values of pressure differen
erted on it and exerts an hydraulic pressure on the 70
tial.
lower side of the piston 48 tending to move it up
Regulator I1 also embodies a stabilizing means
wardly and to further compress spring `41. This
’in the form of a dash-pot 46 which acts to provide
a positive but gradually diminishing gradient increased compression in spring 41 tends to move
against which the pressure differential diaphragm
A75
32 must work when moving in either direction,
the diaphragm 32 upwardly, but this tendency
diminishes at a rate proportional to the rate at 75
4
2,136,114
which the oil iiows through the needle valve into
the space above piston 48 in cylinder 49. This
increased pressure on the dash-pot bellows and on
the bellows of the steam responsive device 35,
slows down the corrective action of diaphragm 32
sufliciently to permit enough time to elapse to
effect the proper adjustment in the steam pres
sure as called for by the change in the pressure
diiferential between the flash tank and the con
10 denser. By the time the steam pressure has been
adjusted to balance the pressure differential act
ing on the diaphragm of regulator I1, the effect
of the dash-pot has diminished to the vanishing
point and the coil spring 41 associated therewith
15 will have assumed the position it normally occu
pies when equilibrium is reached between the dif
ferential acting on diaphragm 32 and the steam
pressure acting on the 4bellows steam responsive
When diaphragm 32 moves upwardly, it moves
-valve 30 upwardly to a position which reduces the
area of opening 18 in the inlet port- of valve body
3l and increases the area of opening 19 in the
exhaust -port at the lower end of the valve body n.
through which air may exhaust to the atmos
phere. Thus, the relative areas of the inlet and
exhaust openings fixes the pressure of the air ex
isting within valve body 3| and as transmitted
through outlet port 80 to pipe 3 I ' which communi
cates with the interior of the housing I8 device
I5 and to the interior of the dash-pot bellows
housing 5|.
A
Valve 38 as shown in'Fig. 3, is yieldingly urged
towards open position, that is, towards maximum
pressure transmitting position by means of a coil
spring 82. Therefore, as the diaphragm moves
downwardly, this spring will move valve 38 down
device 34.
`
wardly
and cause it to follow push rod 11.
20
From the above it will be apparent that theA
The exhaust opening 19 is lformed in a bushing
magnitude of the pressure impulses delivered to 83 which is threaded into the lower end. of the
the steam pressure regulator I3 and to the dash
valve body and provides an adjustment which
pot bellows 50 is proportional to the change in the fixes the amount of travel required to move valve
pressure differential acting on ydiaphragm I1 30 upwardly to its extreme closed position or
25 and/or the steam pressure acting o_n'device 34.
downwardly to its extreme open position, thatA
For this reason, the greater these changes, the is, tothe position which the exhaust port open
shorter will the time of correction be as fixed by ing 19 is closed. '
`
dash-pot 46, because the higher the pressure act
In case it is desired to change the values of
ing on the dash-pot bellows, the higher the rate
30 of oil flow through needle valve 59 will be. This steam pressure required by device 35 to balance
a given differential acting on diaphragm 32, the
action of the dash-pot prevents over-correction of fulcrum roller 36 may be shifted longitudinally of
y the nozzle steam pressure.
lever 35 either towards or away from spring 39.
The dash-pot working in conjunction with dia
The closer fulcrum 36 is to the connection of the
phragm 32 therefore gives stable operation to reg
steam pressure bellows to lever 35, the higher the
35
ulator I1 and avoids over or under adjustments of
the steam pressure whenever a change in the
pressure differential between the ñash tank and
the condenser occur.
.
In Fig. 2 of the drawing, the construction em
40 ployed for providing an operating connection be
tween diaphragm 32 and the valve 30 and between
the diaphragm and the 'dash-pot coil spring 41,
is illustrated. As shown, thrust plates 68 and
6I are disposed on the upper an lower sides of the
45 diaphragm and give support and rigidity to the
central or middle portion thereof. The center
of the diaphragm and the plates are apertured to
accommodate a connecting rod 62, the ends of
which extend upwardly and downwardly, respec
50
tively, through the diaphragm housing’.
The
plates 60 and 6I are held flrmly against the dia
phragm by means of bushings 63 and nuts 64.
In order to provide a pressure tight joint where
rod 62 passes through housing 33, suitable flexible
55 diaphragms 65 are secured between the bushings
63 and Washers 66, the required pressure being
supplied by nuts 64, and by pressure tight sealing
rings 61 which seal the outer edges of the open
ings through which rod 62 passes.
60
,
The lower end of rod 62 is provided with an
anchor block 68 around which the upper end of
coil spring 41 is disposed, and to which it is sel
curely clamped by means of a clamping ring 69
and a screw 18.
65
The upper end of rod 62 is operatively con
nected to valve 30 and lever 35 by means of a
yoke 1I which is secured between the upper -nut
64 and washer 66. The upper end of the yoke is
provided with a flange 12 which overhangs lever
70 35 and which carries a knife edge 13 on its under
side which is engaged by lever 35. The upperside
of this ilange carries a pin 14 having a conical
point which seats in a socket 15 in the lower end
of a push rod 11 that engages the lower end of
75
valve 38. see Fig. 3.
`
'
steam pressure must be to balance a given pressure
diiîerential between the ñash tank and the con
denser, and the farther -it is away from this point
of connection the lower the steam pressure must
be to balance this differential.
To provide _for this adjustment fulcrum roller
36 is mounted on a carriage 84 which is slidable
on >bracket 51. The adjustment of the carriage
may be accomplished by means of a screw 95
which is threaded into the fulcrum carriage and
journalled in a bearing 86 which cooperates with
collars 81 on the screw to prevent its longitudinal
movement. By turning a handwheel 88 fastened
to this screw, the fulcrum carriage and its ful
crum roller may be shifted longitudinally 0f
lever 35 to change the relation between the steam
pressure acting on the nozzles and the pressure
differential between the flash tank and the con
denser.
-
-.
'
`
The operation of the control system above de
scribed is as follows: Assume that the absolute
pressure to be maintained in ilash tank I is P1
pounds per sq. in. and that the absolute pressure
in the condenser is P2 pounds per sq. in., then
the pressure differential in pounds per sq. in. is
equal to (Pif-P2). Assume also that for this
differential of (P1-P2) that the evactor or
venturi 5 requires a steam pressure on the noz
zles II of P pounds per square inch. With these
assumed conditions, regulator I1 is then adjust
ed, as hereinbefore described, until a steam pres-sure of P pounds per square inch balances the
differential of (P1-P2) acting on diaphragm 32.
Under these conditions valve 30 will be in such a
position as to effect the delivery of compressed
air to device I5 and to the dash-pot bellows hous 70
ing 5I at L pounds per square inch. Under these
conditions the steam valve I4 will be held at a
fixed opening, an opening which will deliver steam
to the nozzles II at a pressure of P pounds per
square inch.
75
5
2,136,114
If all of the steam boosters are not operating
and another booster is turned on therel will be a
pressure drop in the steam pressure acting on the
nozzles of these boosters because of the increased
steam flow through valve I4. This reduced steam
pressure is reflected in the steam pressure re
sponsive device 35 with the result that regulator
I1 is unbalanced. When this happens the dia
phra‘gm 'moves downwardly to open valve 30 an
10 amount depending upon the unbalance and in
creases the pressure of the air in device I5. This
results in a further opening of valve Il and in
creased steam pressure. 'I'he increased steam
pressure results in increased steam iiow lthrough
15 the booster nozzles so that the pressure in the-
condenser is increased thereby increasing the dif
ference between the pressure in the iiash tank
and condenser. This increase in differential fur
tions in the pressures existing in the vacuum
chamber and the condenser.
`
-2. In a steam reirigerating system having a
vacuum chamber in which iiuid is cooled, a con
denser, and a steam jet compressor connected be
tween said chamber and condenser, a steam noz
zle disposed to deliver steam at' high velocity
through said compressor to establish a partial>
vacuum in said chamber, a source of supply oi
steam for said nozzle, and means for varying the 10
pressure of the steam delivered to said nozzle, the
combination of a device having means respon
sive to the pressure of the steam delivered to said
nozzle, and to the difference between the pres
sure in the vacuum chamber and in the con 15
denser for so regulating the steam pressure vary
ing means that the pressure of the steam as de
livered to said compressor is caused to bear a
deñnite relationship to the diilerential in pres- `
ther unbalances regulator I‘I in a direction which sure between the flash tank pressure and the 20
will further increase the air pressure in device I5
pressure.
’
and further increase the~ extent of opening of the condenser
3. I_n a' steam refrigerating system having a
steam valve I4. This action continues until the flash tank in which ñuid is cooledby the action
steam pressure acting on the nozzles of the oi' partial evaporation, a condenser, and a booster
boosters-is in balance with the pressure diEer
connected between said tank and condenser, a 25
ential (P1-P2) acting on diaphragm 32. At this steam
nozzle disposed to deliver steam through
new equilibrium between steam pressure and pres
said booster at high velocity to establish avac
sure differential, regulator I‘I will maintain a uum in said flash tank, means for controlling the
higher steam pressure on the booster nozzles but nozzle steam pressure, means responsive to flash
the value of Pl-P2 will be the same for any value
tank pressure and condenser pressure', means re 30
of steam pressure required to maintain it. Regu
sponsive to the nozzle steam pressure, and means
lator I1 acts to regulate the steam pressure di
jointly
controlled by all said pressure responsive
rectly in accordance with the diiïerential in pres
means for operating the nozzle steam pressure
sure between the ilash tank and the condenser controlling means to maintain a predetermined
independently of the number of boosters in use relationship between the nozzle steam pressure 35
at any particular time._ And regardless of the
number of boosters in use, the steam pressure f and the diiîerence between the flash tank and
condenser pressures.
acting on nozzles II will be regulated tomain
4. In a steam refrigerating system having a
rtain the value of (Pl-P2) constant even though “
ilash tank in which iiuid >is cooled by the action
the »individual values of P1 or P2 may vary slight
ly. But since regulation of the steam pressure of partial evaporation, a condenser, and a plu 40
results from a change in either P1 or P2 or vin
the steam pressure and since regulator I'I is ini
tially adjusted to maintain the difference be
tween‘Pl and P2 constant, it will be apparent that
the steam pressure will always be adjusted to
maintain this difference whenever P1 or P2 or
rality of steam jet compressors connected be
tween sald tank and condenser, each compressor
having a plurality of steam nozzles disposedto
deliver steam through said compressors at high
velocity to establish a vacuum in said ñash tank, 45
means for controlling the steam pressure at the
both change in values to depart from a constant - nozzles, means responsive to the ilash tank pres
diiïerence between them.
-
sure and the condenser pressure, means respon
`
While but one embodiment'of the control sys
tem or this invention has been shown and de
scribed, it will be apparent to those skilled in this
sive to the nozzle steam pressure, omeans jointly
controlled by` all said pressure responsive means 50
for maintaining a predetermined ratio between
art that various modifications and changes may A thev nozzle pressure and the difference between
be made in thesystem and in the operative ele
ments of the system without departing either
from the spirit or the scope of the invention.
~ What I claim as new and desire to secure by
Letters Patent is:
1. In a steam reirigerating system having a
vacuum chamber in which iiuid is cooled, a con
denser, and a steam :let compressor connected be
tween said chamber and condenser, a source of
supply of steam connected to _flow .through said
the iiash tank and condenser pressures ,inde
pendently ci.' the number of compressors in op
eration, and means for adjusting the ratio of
steam pressure at the nozzles to the pressure
5.5
differential between the flash tank and condenser.
5. In a steam refrigerating system having a
ilash tank in which iiuid is cooled by the action
of partial evaporation, a condenser, and a booster 60
connected between said tank and condenser, .a
steam nozzle disposed to deliver steam through
said booster at high velocity to establish a vac
uum in said ilash tank, means for controlling
the nozzle steam pressure, means responsive to
delivered to said compressor, and a source or flash tank pressure and condenser pressure, and
supply of cooling iiuid for the condenser for con vmeans controlled by said pressure responsive
densingrthe steam delivered thereto, the combina means for operating the nozzle Asteam pressure
tion of a device- having means responsive to the
controlling means to maintain a predetermined
pressure of the steam as delivered to said com
relationship
between the nozzle steam pressure 70
pressor and means responsive to the pressure in
70 the
and the diiîerence between the ilash tank and
vacuum chamber and condenser, for so con
trolling the steam pressure varying means that condenser pressures.
compressor to establish a partial vacuum in the
chamber, means for varying the’pressure of steam
the pressure of the steam as delivered to said
compressor is varied in accordance with varia
s
-
AIFRED A. MARKSON.
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