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Патент USA US2110581

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March 8, 1938.
H. 1.. SMITH, JR
Filed Aug. 17, 1935
4 Sheets-Sheet 1
,\ A .
March 8, 1938.
H. |_. SMITH, JR
Filed Aug. 17, less‘
4 Sheets-Sheet 2
_ ‘
a (
March 3, 1933-
' H. L. SMITH.‘ JR
Filed Aug. 17, 1935
4 Sheets-Sheet 3
' A‘?
March 8, 1938.
Filed Aug. 17, 1935
4 Sheets-Sheet 4
Patented Mar. 8, 1938
Horace H4. 8th, in, lltlcond, We“, osslgnor to
Thermal Engin w 1: s’ Con-pollution, Richmond,
We... a coration oi Virginie
Application A
it, 1935, Serial No. M1535
‘This invention relates to air conditioning and
ereted systems now in use, the control is inter~
more particularly concerns an improved air con
ditioning system for use on railway passenger cars
mittent, the epperatus operating at maximum
of steam roads.
The provision of conditioned air in railway pas
senger cars involves generally two conflicting
problems; that of maintaining comfortable con
ditions and that of economy. The power avail
able on steam trains for the operation of auxiliary
capacity whenever it is turned‘on. Since the
system must have scient capacity to prop,
erly cool the car under the most adverse outside 5
temperature, conditions met with in operation, the
intermittent control produces undesirably wide
fluctuations in car temperature under moderate
outdoor conditions, and iurther results in lowered _
equipment, such as air conditioning apparatus, is
e?iciency due to the power losses involved in ~10
quite limited.
starting the apparatus at frequent intervals.
With the above and other considerations in
On the other hand, passenger cars
are necessarily subjected to widely varying tem
perature conditions'in the course of an average
run and comfortable atmospheric conditions can
be maintainedtherein only if a very ?exible sys
' tem of relatively large cooling capacity is pro”
is controlled in an emcient and economical man- -
ner by varying the cooling effect in accordance
with the heat load imposed whereby the our air
‘ 'inhthe past, railway car air conditioning sys
tems have been a compromise between two de
sired ends, the maintenance of comfortable con
ditions and reasonably economical operation.
Known systems operated in whole or in part by
electricity involve a high initial cost and high
operating expense due to their low emciency.
Thus when such systems are installed on a rail
way car, it is necessary to replace the usual car
lighting generator and battery with electrical
generating and accumulating equipment 01’
greatly'increased capacity and this replacement
materially increases the initial cost of the in
stallation. The energy for operating electrically
driven systems is delivered from the locomotive
through the draw bars, the axle driven generator,
the storage battery and the electric motors to the
refrigerating apparatus, and consequently, the
overall ei’?ciency of the system is low and the
operating cost correspondingly high.
mind, it is proposed in accordance with the pres~
ent invention to provide an improved railway our
air conditioning system for steam trains which 15
Steam operated railway car air conditioning
systems employing steam jet vacuum boosters
40 have been used to a certain extent, and in general,
are more economical to install and operate than
temperature is maintained at the desiredvelue
without wide fluctuations. Other objects of the 20
invention include a system of this nature which
is small and compact, inexpensive to install and
low in operating cost. A further feature oi’ the
invention involves the provision of improved and I
simpli?ed means for operating the system when 25
the railway car is standing in a yard or station
with‘ no locomotive connected thereto whereby
a car may be precooled before‘ it is connected in
a train and occupied by passengers.
In general, the above and other objects of the 30
invention are carried out by providing a com“
pression type reirigereting system to‘ cool the
car and driving this system with a steam prime
mover capable of e?icient operation over a wide
range of speeds. In accordance with the inven- 35
tion, the speed of the prime mover and hence the
speed of the refrigerant compressor is varied by
means responsive to atmospheric conditions in
.the car, and in this manner, the car tempera
ture is maintained constant at the desired value 40
and a, very high operating emciency is obtained.
I have found that a reciprocating steam engine
electrically driven systems. However, such sys
tems operate effectively under maximum steam ‘ of the uni?ow type is particularly adapted for
supply only, since the e?lciency of a. steam jet or use in my improved system.
The speed control is conveniently accomplished 45
injector in creating a vacuum falls rapidly as the
steam pressure on the jet is reduced, and as a by adjustment-of the steam supply to the prime
mover and to this end, I preferably provide means
practical matter, effective cooling can be ob
tained only if the steam is" supplied continuously responsive to both the speed of the prime mover
at the rated pressure. The piping available for andthe temperature of the car, whereby the com
all supplying steam to the various car carried units
pressor operates at a speed which is maintained 50
of a train is-limited in size, and when a large
constant in spite of steam pressure variations or
number of car units are in operation, the steam
variable load factors so long as the car tempera
ture is within thedesired range, but which speed
ful operation and insu?lcient car cooling results. is varied to compensate for departures from the
In both the electrically driven and steam op- , desired car temperature conditions.
pressure falls off in the rearward cars and waste- ,
Therefrigerant compressor is a constant volume
device, acting on a relatively dense gas, and ac
cordingly, the compressor efilciency increases as
tional construction which has been diagrammat
ically illustrated at P in Figures 6 and 'l. The
system is of the type in which a refrigerant from
its speed drops. High compressor speeds result
a refrigerating unit, or a suitable heat transfer
in high gas velocities and high friction losses.
There is, of course, a low limit to the, speed at
medium cooled by such refrigerant, is circulated
in heat exchanging relation with air supplied to
which it is economical to operate a refrigerant
or circulated in the car. The particular form of
car cooling coil and air propelling means forms no
compressor since the relation between the initial
investment and required capacity must be taken part of the invention and various forms of appa
However, since heat load condi-' ratus may be employed for this purpose. In the
10 into account.
one or more intake openings 3 into a chamber 4
20 tem is better suited for use with steam supply
facilities of multiple-car trains than previously
known systems. With known steam systems,
which are governed by a full-on or full-oi! con
trol, the units on the several cars of a train fre
quently operate simultaneously and the rapid
steam consumption ‘by the forward car units so
far reduces the steam pressure on the rearward
car units that these units operate very ine?l
‘ciently and usually fail to produce the required
30 cooling effect’until after the forward car units
have stopped operating. With. my improved
variable speed steam system, the amount of steam
drawn from the train line by each unit is throt
tled to the minimum value which will maintain
35 the desired car temperature under continuous
operation, and sudden ?uctuations of train line
steam pressure with resultant ine?icient or inade
quate operation of the rearward car units is
In accordance with one embodiment of my in
vention, I provide an. over-running clutch or
equivalent means in the driving connection be
tween the steam engine and the refrigerant com
pressor, and further provide an electric com
45 pressor driving motor which may be readily con
nected directly to drive the compressor independ
,ently of the steam engine. With this arrange
side outlet, the steam engine remaining station
ary during such operation because of the over
running clutch in its driving connection.
In describing the invention in detail, reference
55 will be made to the accompanying drawings in
Figure 1 is a plan view of a car carried refrig
erating unit embodying the invention;
Figure 2 is a side elevation of the unit shown
80 in Figure 1;
‘located above the ceiling of .the car vestibule ‘I,
and is propelled by the fan through a duct 5 to
suitably placed ceiling outlets 6 in the car. 'A
cooling coil 8 is located in the chamber 4 in heat
exchanging relation with the air drawn there
thrnugh and this coil is at times supplied with
refrigerant or other cooling ?uid from a refrig
erating unit hereinafter described. The fan 2
may be operated by an electric motor, as shown.
The fan and motor may be of relatively small
capacity and may replace the usual electric fans
customarily installed in railway passenger cars. 25
Air may be discharged from the car through the
doors, windows or other air pervious openings
thereof, or special air outlet ducts may be pro—
vided, if desired.
The refrigerant‘ for cooling the air delivered to 30
the car is supplied by a refrigerating unit carried
beneath the car in a housing generally designated
H. Thehousing may take any suitable form and
is preferably disposed beneath the car frame and
between the center line of the car and the clear 35
ance limits at one side thereof, as shown in Fig
ure 3.
The refrigerating unit proper comprises gen
erally a mechanical refrigerant compressor 10,
preferably of the reciprocating type, a refrigerant
condenser C and suitable means such as the fans
II and I2 for drawing a current of cooling air
over the condenser surfaces. The intake I3 of
the compressor III is connected to draw refrig
erant gas from the car coil 8 by a pipe l4, prefer
ably provided with ,a cut-off valve IS. The dis
charge IS, of the compressor I0 is connected
ment, the‘ car may be pre-cooled by merely con
necting the electric motor to the refrigerant
50 compressor and supplying current from a track
embodiment shown in Figure 6, fresh air from
outside of the car is drawn by a fan 2 through
tions vary widely and operation is for the most
part well below maximum capacity, I obtain a
condsiderable increase in emciency by varying
the compressor speed in accordance with load
requirements since in this manner, the com
pressor always operates at the highest efficiency
obtainable for the load imposed and further,
losses resulting from frequent starts are avoided.
My improved variable speed steam driven sys
through a pipe I‘! and a‘ valve l8 to the condenser
C. ‘ The outlet of the condenser C passes through
a cut-off valve is and a pipe '20 to the car cool
ing coil 8, the proper condenser pressure being.
maintained by a suitable expansion valve 2|.
The condenser may take any suitable form and
preferably includes ?nned coils or passages 22
communicating with a liquid refrigerant accumu
lator 23.
"I‘he condenser cooling fans H and I2 are dis
posed in suitable circular openings in a shield 24
extending across the inner face of the condenser
C, and air drawn through the condenser passes 60
laterally through the housing H and out through
the louvers 25 in its outer wall. The fans H and
Figure 4 is an enlarged detailed view, partly in I2 are journaled in suitable brackets 26 and 21
and are driven by a single shaft 28 through suit
section, of the compressor driving mechanism;
Figure 5 is a sectional view of the governor able spiral gears 29 and 30.
The refrigerant compressor ‘I0 is driven by a
Figure 6 is a sectional elevation of a railwayv steam prime mover, which preferably comprises
passenger car equipped with an air conditioning a direct connected reciprocating steam engine of
system embodying the invention; and
the uni?ow type, which is illustrated at E. In
Figure '7 is a diagrammatic view of a trainof general‘, the steam prime mover employed should 70
passenger cars equipped with systems embodying be capable of e?lcient operation over a wide range
the invention.
of speeds, and I have found the uni?ow type of
Referring to the drawings, my improved rail
steam engine admirably suited to this purpose.
way car air conditioning system has been shownv The crank shaft 3! of the engine E is connected
to the compressor shaft 32 through an over 75
75 as applied to a railway passenger car of conven
Figure 3 is an end elevation of the car carried
running clutch or equivalent means 88. As shown
in Figure 4, this clutch may take the form of an
inner element 34 connected to the engine shaft
8| and having a ‘plurality of cam recesses 88 there
in carrying balls or rollers’ 88 and surrounded by
an outer element 81 ?xed to the compressor shaft
82. As will be understood, rotation of the inner
element 84 by the engine E in a counterclockwise
direction, as viewed in Figure 4, causes the rollers
the frame of the engine ‘E and driven from the
engine shaft through suitable gearing, not shown.
The governor has two centrifugally operated
weighted elements 84, pivotaliy supported on a
cross piece 85 ?xed to the governor shaft 88. A
sliding collar 81 carried by the shaft 88 is moved
along this shaft by the outward movement of the
centrifugal elements 84, and the movement of
the collar 81 is transmitted to a shaft 88 by the
38 to lock in the cam recesses 88 and so form a ' arm 88. The shaft 88 carries an arm 18 outside 10
driving connection between the engine and the
of the governor casing, and a tensioned spring
compressor. If the outer element 81 is driven
independently of the engine E, the rollers 88 are
‘ll connected to this arm exerts a force thereon
which opposes the outward movement of the cen
released and the engine remains stationary.
I prefer to provide an electric motor for oper
ating the compressor ll independently of the
engine E when the car carrying the system is not
coupled to a- locomotive whereby the car maybe
precooled before it is occupied by passengers. To
20 this end, a motor 88 is provided, having a friction
wheel 88 on its shaft disposed parallel to the outer
trifugal elements 84. The end of the spring 1|
is connected to a pivoted lever 12, the movement
of which varies the force exerted by the spring
‘H on the lever ‘III, as is apparent from the show
ing in Figure 2. A second arm 13 is connected
to the shaft 58 of the governor G and is in turn
member 81. of the over-running clutch. A fric
tion idler 48 is slidably carried by a suitable
bracket 4| and is movable to and from a position
to simultaneously engage and form a driving con
nection between the motor friction wheel 39 and
the outer clutch member 81. The idler 48. may
be operated in any suitable manner, and as shown,
a pneumatic diaphragm mechanism 42 is pro
30 vided for this purpose. This mechanism includes
a diaphragm 43 ‘acting against a spring 44 and
operating a plunger 45 connected to the sliding
journal 48 of the idler 48. Compressed air from
a suitable source is supplied to the mechanism
42 through a pipe 41 under the control of a man
ual three-way valve 48. when the valve 48 is
manipulated to admit air pressure to the dia
phragm 48, vthe idler is moved to engage the wheel
88 and clutch member 81, thus establishing a
40 driving connection between the motor 88 and the
compressor Hi. When the valve 48 is manipulated
to cut of! the air supply and discharge air from
the diaphragm chamber of the mechanism 42,
the spring 44' moves the idler 48 out of engagement
with the friction wheel 88 and clutch member 31,
thus breaking the driving connection.
The fan operating shaft 28 is ‘driven with the
connected through the links ‘l4, ‘l5, ‘I8 and ‘I1
to the stem of the steam engine throttlevalve t8.
Suitable means are provided for moving the
lever 12 and so varying the tension of the gov
e‘rnor spring ‘H in accordance with changes in
air temperature within the car P.
In the dis
closed embodiment, this is accomplished by
means of a pneumatic diaphragm mechanism 18
having a ?exible diaphragm 19 connected to the
lever ‘I2 through a plunger 80. The downward
movement of the diaphragm 78 and plunger 88 30
is opposed by a spring 8| and compressed air
from a source indicated by the pipe 83 is sup
plied to the upper surface of the diaphragm 18
through a pipe 84 under the control of a ther
mostat 82 in the car. The thermostat 82' is of
known construction and acts to reduce the air
pressure on the diaphragm ‘I8 as the car air tem
perature rises above a predetermined value, and
to increase this air pressure as the car air tem
perature falls below the predetermined value.
In- the position shown in Figure 2, it is as
sumed that the car air temperature is above the
prising the aligned'pulleys 58 and 58 and the belts
88 engaging these pulleys. The desired belt ten
desired value, and accordingly, a low air pres-‘
sure is applied to the diaphragm ‘I8 and the
spring 8| has lifted the plunger 80 and moved 45
the lever 12 to its highest position against a
stop 85, placing the governor spring ‘II under
maximum. tension. In this condition, the cen
trifugal elements 84 of the governor are moved
inward, turning the shaft“ in a clockwise di 50
sion is maintained by an idler 5| engaging the
rection as viewed in Figure 2 to a point where
lower span of the belts 58 and pressed against the
belts by a spring 82 which is tensioned between a
?xed support and the pivoted idler carrying arm
the throttle valve 56 is opened to a considerable
compressor l8 through a driving connection com
83. ~
extent, and’ the, engine E and compressor I8
operate at a comparatively high speed which is
limited and controlled by the governor G. The
Steam for operating the engine E is supplied - high speed operation of the refrigerating system
from the locomotive 58 through the usual train reduces the car air temperature and when this
steam line 5| and a branch pipe 52 leading to temperature falls to a predetermined value near
each car carried unit. The steam passes through
a manual supply valve 53, a water separator 54,
an automatic cut-off. valve 55 and a throttle valve
55 to the engine E. Exhaust steam from the t‘"
gine E passes out of the housing H through the
‘ pipe 51.
the minimum comfortable temperature, the in
crease in air pressure on the diaphragm 18 moves 60
the plunger 88 and lever 12 to their lowest posi
tions, reducing the tension on the spring ‘II to
the minimum value. The centrifugal elements
64 of the governor accordingly move outward,
turning the governor shaft 88 in a counter
During operation of the system, the supply of
steam to the engine E is automatically governed
by means Jointly responsive to the engine speed
valve 55 to a point where the engine and com
and the temperature of the air in the car. In
pressor operate at minimum speed. If, under
the disclosed embodiment, this is accomplished
these conditions, the heat load in the car is so
light that even at minimum speed operation the 70
refrigeratingsystems lowers the car temperature
70 by providing a speed responsive governor G con
nected to operate the steam engine throttle valve
58, and by modifying the action of the governor
in accordance with changes in car temperature.
Any suitable form' of speed governor may be
75 used. The governor G disclosed is mounted on
clockwise direction and so closing the throttle
to the minimum desired value, then the resultant
further increase in control air pressure acts
through the pneumatic steam valve 55 to cut off
the steam supply to the engine E and so stop 76
the refrigerating system. The operating mech
anism of the valve 55 is of the pneumatic dia
phragm type described above, and air pressure
is supplied thereto from the thermostat pipe I‘
through the pipe 88, as shown in Figure 2.
As the car air temperature increases from the
minimum value, the reduction in the air pres
sure controlled by the thermostat 82 ?rst opens
the automatic pneumatic steam valve 55 and so
starts the engine E and compressor I. at mini
ing a mechanical refrigerant compressor, means
connected to said refrigerating unit for cooling
the interior of a railway car, a variable speed
steam engine connected to drive said compressor,
means responsive to both the temperature in said
car and the speed of said engine for variably
controlling the supply of steam to said engine
and means responsive to a minimum car tem
perature for cutting of! the supply of steam to
said engine independently of the action of said 10
mum speed. A further rise in car temperature means responsive to both car temperature and
further reduces the control air pressure and the engine speed.
2. A railway car air conditioning system com
diaphragm ‘I! of the mechanism ‘I8 is lifted by
prising a car carried refrigerating unit includ
the spring ll, thus lifting the lever. ‘I2 and in
15 creasing the tension on the governor spring ‘II.’ ing a mechanical refrigerant compressor, means
This increased governor spring tension moves connected to said refrigerating unit for cooling
the centrifugal elements 84 inward. turning the the interior of a railway car, a variable speed
shaft 88 in a clockwise direction and opening the steam engine connected to drive said compressor,
throttle valve 56 to admit more steam and so a speed responsive device driven by said steam
engine comprising means moved by centrifugal
increase the speed of the engine E and com
pressor l0.
force acting against a spring, means for variably
Although in the foregoing description, the controlling, the rate of supply of steam to said
operation of the control equipment from maxi
engine in accordance with‘the movement of said
mum to minimum speed has been described, it centrifugally operated means, means responsive
will be understood that under normal conditions, to the temperature in said car for varying the
that is, a continuing heat load on the car, the force of said spring and further means respon
system will operate continuously at some inter
sive to the temperature in said car for cutting
mediate speed, the governor G maintaining the off the supply of steam to said engine when the
speed constant at a value determined by the car temperature reaches a minimum value.
3. A railway car air conditioning system com
temperature in the car, and the thermostat al
tering this speed, as required to compensate for prising a car carried refrigerating unit includ
changes in car temperature.
ing a mechanical refrigerant compressor, means
From the above description, it will be seen connected to said refrigerating unit for cooling
that the governor G and its thermostatic con
the interior of a railway car, a variable speed
steam engine connected to drive said compressor,
35 trol act tovary the operating speed of the re
frigerating system in accordance with changes a speed responsive device driven by said steam
in the heat load conditions in the car. As long
as the car temperature remains constant at the
desired value, the governor maintains the com
engine comprising means moved by centrifugal
force acting against a spring, means for vari
ably controlling the rate of supply of steam to
40 pressor speed constant but any change in car - said engine in accordance with the movement of ,
temperature produces a corresponding change said centrifugally operated means, and means re-_
in compressor speed which counteracts and cor
rects the car temperature change. With this
arrangement, the compressor operates continu
45 ously so long as cooling is required, and further
operates at all times at the lowest possible speed
which will maintain comfortable car conditions
under the heat load imposed. Since the com
pressor e?lciency rises as its speed is reduced, the
‘so system operates very efliciently and further, since
sponsive to the temperature insaid car for vary.
ing the force of said spring.
4. In a railway car air-conditioning system, in
combination with a steam locomotive and a pin-1
rality of cars connected thereto, a train steam
line arranged to be supplied with steam from
said locomotive and having a connection extend
ing to each of said cars, a refrigerating unit car
ried by each car and including a mechanical re
the refrigerating system operates continuously
frigerant compressor, each refrigerating unit be 50
while cooling is required, the losses involved in
ing arranged to cool the interior of the car asso
starting the compressor are avoided.
By the use
ciated therewith, a variable-speed steam engine
of the system disclosed, dependable cooling can
55 be obtained in all‘ of the cars of long trains.
Due to the throttled operation of car cooling
units, sudden drops in train line steam pressure
on each of said cars for driving the refrigerant
compressor thereon, means for supplying steam
from said connections to the steam engines on
are avoided- andthe operation of forward car
units does not reduce the steam pressure avail
80 able on rearward cars to a point where inade
to both temperature in such car and the speed
of the steam engine thereon for variably con
quate cooling results. Differences in train steam
line pressure are automatically compensated for
by the speed governors of the various car units,
and accordingly it is unnecessary to manually
65 change the adjustment of car equipment in ac
cordance with the position of the car in a train.
I claim:
1. A railway car air conditioning system com
prising a car carried refrigerating unit includ
said cars, means on each of said cars responsive
trolling the supply of steam from the associated 60
connection to said engine, whereby a sumcient
amount of steam is supplied to each engine,
independently of the operation of other engines,
to operate its associated compressor in accord
ance with the coolingrequirements of the asso
ciated car, and means on each of said cars rc
sponsive to a minimum car temperature for cut
ting off the supply of steam to the engine.
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