Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
I 1 ~3972
rt is well known to provide water cooling ~or engines in railway
cars. ln some cases, the heat generated by the engine has been used for other
purposes.
Because of the varying heating requirements of a railway car due to
the wide variations of temperature conditions under which it operates, it is
difficult to utilize the waste heat from an engine directly and continuously
to provide conventional heating for the car. The reason for this is that there
are times, during warm or mild temperature conditions, when little or no heat
is required and other times, as during the winter months, when the heating
requirements are high.
One such system making use of waste heat from an auxiliary power
unit is described in a Canadian patent application entitled "A Heating System
for a Railway Car for Utilizing Waste Heat From an Engine", Serial No. 343338
filed Januar~ 9, 1980 and assigned to the same assignee as the present invention.
In systems such as involved in the aforementioned application, the
various conduits and temperature responsive means are located at desired
locations within the car. Heated water is selectively applied from the waste
heat system to overhead heating coils dependent upon the temperature detected
inside the car.
~hi~le the system described in the aforementioned application is
satisfactory, it is sometimes desirable to provide cars of the same basic design
which are independentl~ powered and which do not include auxiliary power units
which generate waste heat to provide hot water to heat the interior of the car.
~n order to take advantage of utilizing the same basic design for both types
o~ cars, it is desirable to utilize as many as the same parts as possible to
provide heat for both types of cars. It is especially desirable to use the
same conduits and temperature responsive means located in the same places within
.~
9 7 2
the car.
It is an object of this invention to provide an improved heating
system for a railway car.
rt is a further oboject of this invention to provide an improved
heating system for a railway car in which the main conduits and temperature
responsive means are adapted to utilize either waste heat for an auxiliary
power unit or heat from separate electrical heaters.
rt is still a further object of this invention to provide an
improved heating system for a railway car in which waste heat from an auxiliary
power unit may be supplemented by heat from electrical heaters utilizlng the
same conduits and temperature responsive means.
rn accordance with the present invention, a heating system is
adapted to utilize either waste heat from an auxiliary power unit or heat from
electrical heaters. Water from an auxiliary power unit may be applied to a
heat exchanger and circulated to overhead heating coils dependent upon the
operating states of temperature responsive means within the car. When the car
~s designed without the auxiliary power unit or heat exchanger, electrical
water heaters heat connected in series provide hot water to the overhead
heating coils. The water is circulated in response to the temperature
responsive means within the car. The heat from the hot water heaters may
supplement the waste heat of an auxiliary power unit if it is used and supplies
insufficient heat for the interior of the car.
The invention will now be described in greater detail with reference
to the accompanying sole figure of the drawing illustrating, partly schema~ically
aDd partly in block diagram form, a heating system for a railway car, in
accordance with the present invention.
The system described is used in conjunction with the present invention.
~ ~ 63972
A portion of the system to be described generally herein is
described in detail in the aforementioned patent applicatlon.
Specifically, various details relating to the operation of the
auxiliary power unit and the heat exchanger associated therewith are described
in detail.
Basically, water is selectively pumped through a clcsed loop
through a pipe 12, through the overhead heating system to be described and back
to the interior of the car through a pipe 14.
An auxiliary power unit including a water jacket 20 is filled with
~rater from a source 18. The source 18 may include a water fill or drain valve
at the side of the car which is closed following filling to close the system.
The water is circulated through the water jacket 20 of the auxiliary power unit.
When the auxiliary power engine is first started, water is circulated for a
short time in a warm-up loop and is circulated by a pump 22 forcing water in
the direction of the arrows through the water jacket 20 and a thermostat 24.
The water from the thermostat 24 directs the water back to the pump 22 until
it reaches a certain predetermined temperature. The thermostat 24 comprises a
thermostat valve capable of steering the water in one of two paths. When the
temperature is below 170F, for example, the thermostat 24 causes the water to
pass through the warm-up loop descEibed. When the temperature reaches 170F.,
the thermostat 24 blocks the water in the warm-up loop and directs it into a
second loop or circulating path.
A~ter the water in the warm-up loop has reached 170F., the water
~lows through the second loop whlch includes a heat exchanger 26, also generally
included in the system involving an auxiliary power unit. The water from the
heat exchanger 26 passes through another thermostat 28. The thermostat 28,
acting as a valve, is also capable of directing the water in either of two
1 1 63972
paths depending upon the temperature operating condition. The water passes
through the thermostat valve 28 to a line 30 back to the inlet of the loop
including the water jacket 20. This happens, for example, when the temperature
is above 170F., but below 180F. When the water reaches a predetermined
higher temperature, such as 180F., the thermostat valve 28 blocks the water
in the second loop and directs it to a third loop. In effect, the system thus
far described is aimed at keeping the heat exchanger 26 at 180F. after its
initial warm-up period. When this temperature is exceeded, the third loop
provides greater cooling for the auxiliary power engine.
When the water temperature exceeds 180F., the thermostat valve 28
prevents water from flowing in the second loop including the line 30 and
directs the water through the third loop which includes lines 32 and 34 which
lead to overhead radiators 35. The thermostat valve 28 is directly connected
to the line 32. The line 34 leads back to the inlet of the pump 22 and
through the water jacket 20.
The third loop involving the lines 32 and 34 is used prlmarily to
prevent overheating of the engine and provides extra cooling when the temperakure
goes above 180F. Thus far the system described has not provided any heat for
the interior of the car.
A water circulating pump 36 is connected to circulate water in the
loops including the pipes or lines 12 and 14. The water from the pump 36 is
connected to pump water in one of two different paths. The first pàth is from
the pump 36 to a check valve 38, which may be a spring loaded check valve, to
line 12. The water from the lines 12 and 14 are connected to overhead heating
coils 40 and 42. The water from the lines 12 and 14 are connected to the
heating coil 40 and 42 through water heaters 44 and 46, respectively. The
water heaters are connected in series with the overhead heating coils.
1 ~ 63972
The heat generated ~y the hot water and heating coils 40 and 42 is
carried by air which may be forced by ~ans or other means not illustrated into
the interior of the car.
The second path from the pump 36 is through the valve 38 to a
solenoid operated valve 48., The pump 36 will operate only when it is desired
to heat the car depending upon the heating or air conditioning requirements
in the car. For example, car temperature control means 13 controls the
operation of the heating system. The temperature control means 13 may include
various thermisters or other similar elements disposed in an overhead duct of
the system. Dependent on the temperature control settings, various circuits
including switches and the like are operated by the thermisters or other
thermocoupling elements. Such elements and circuits are well known to those
skilled i~ the art and therefore not described or illustrated in detail. The
pump 36 operates only when it is desired to heat the car or heat super cooled
air during air conditioning by having heated air produced by the overhead
heating coils 40 and 42. Output ~ignals from the temperatur0 control means
13 are applied to selectively operate the pump 36 and valve 48 when predetermined
temperatures are reached.
rn one type of operation when the heating system reaches a pre-
determined temperature, for example, about 61-65F., the temperature control
means 13 responds to close a switch to apply power to drive the pump 36 and to
open the thermostat or modulator valve 48. Water is then circulated from the
pump 36 through the valve 48, through the heat exchanger26 and to the overhead
heating coils 40 and 42. The check valve 38 is a spring loaded valve and is
set to have a slightly higher resistance path than the path to the heat
exchanger 26 ~hen the valve 48 is opened. Consequently, water will flow through
this path as long as the pump 36 continues to operate with the valve 48 opened.
1 :1 63972
The valve 48 wlll remain open as long as the temperature is below
a predetermined temperature, for example, between 72 and 74F. When the
temperature of the duct exceeds about 74F., the valve 48 closes. When the
valve 48 closes, the water from the pump 36 is prevented from passing through
the heat exchanger 26~ overcomes the spring loadlng of the valve 3~ and passes
therethrough.
The present system is adaptable for use ln two dif~erent types of
cars. For example, one type of car may not include an auxiliary power unit
having the water jacket 20, heat exchanger 26 and various other associated
parts. However, some of the components for causing the water to circulate
through a line 12 and to be returned through the line 14 may still be employed.
In such systems not including auxiliary power units, a separate or independent
means must be provided to provide heat for the interior of the railway car.
Consider now a situation in which no auxiliary power unit including such items
as the water jacket and heat exchanger 26 are involved. In this case, the
same temperature responsive means 13 may be used. ~lso all the various
temperature control elements within the car may be disposed in the same
locations and operate in the same manner as when an auxiliary power unit is
involved. In the latter case, not involving an auxiliary power ~mit, at a
predetermlned temperature within the car, the temperature responsive means
13 water is circulated to and from the lines 12 and 14 in the manner previously
described.
The ~ater in the loop 12 is circulated through the water heater
44 through a spring loaded valve 45, through a normally open solenoid valve
52 to the overhead heating coil 40. The water is returned from the heating
coil 40 through line 14. The operation of the solenoid operated valve 52 is
connected and is dependent upon the signals from the temperature responsive
I 1 63972
means 13. The connection between the temperature responsive means 13 and the
solenoid operated valve 52 is illustrated by a dashed line.
~ n like manner, the water from the line 12 is transmitted to the
hot water heater 46. The water from the hot water heater 46 is then circulated
through a spring loaded valve 47, through a solenoid operated valve 54 to the
overhead heating coil 42. The water from the overhead heating coil 42 is
returned through the line 14. The solenoid operated valve 54 is likewise
connected to the temperature responsive means 13 as indicated by the dashed
lines, with its operation therefore dependent upon the temperature conditions
inside of the car.
The solenoid operated valves 52 and 54 are therefore disposed to
electrically connect the water heaters 44 and 46, respectively, at the appropriate
temperatures. The solenoids may be located within the car and not necessarily
adjacent the water heaters.
Means for operating the water heaters 44 and 46 may be provided by
control units 49 and 51 connected to a suitable power source. These units may
include mercury switches~ capillary tubes or the like adapted to turn on the
hot water heaters 44 and 46 independent of the system described and keep the
water at a preset temperature~ for example 160F.
The hot water heaters 44 and 46 may be used independently when
heat is desired within the car as determined by the various temperature control
devices within the temperature control means 13 within the car. This would
be a case where no auxiliary power unit was incorporated into the car. In
cases where an auxiliary power unit is employed, it is possible that it may
not generate sufficient waste heat to heat the interior of a car. In this
event, the hot water heaters 44 and 46 may be selectively actuated or operated
to provide supplemental heat for the waste heat system within the car.
~ 1 63972
The present inventlon makes it possible, thereforel to design a
heating system which is compatible with two different types of cars, one with
an auxiliary power unit and the o~her without the auxiliary power unit
including such equipment as the heat exchcmger or water jackets. The
temperature control means 13 would be basically the same in both types of cars.
