Note: Descriptions are shown in the official language in which they were submitted.
1~69~
This invention relates to hydraulic apparatus principally
intended to supply hydraulic requirements for retarders in a
railroad classification yard.
Railroad cars are segregated according to destination in
a rallroad classification yard. The cars to be classified or
separated according to destination are switched to the various
classification tracks. It is customary to slow the cars to a
safe coupling speed by means of retarders insta~led at
predetermined positions along the classificatior. tracks.
llydraulic controls are usually employed. U.S. patent ~os.
3227246 and 3809188 disclose retarders which employ hydraulic
cylinders.
The hydraulic requirements are very extensive since the
hydraulic fluid must be transmitted under pressure over a
considerable distance. The required force is of considerable
magnitude. If there is a pressure failure, the car cannot be
brought to a safe speed, in which event the car couplers and
the lading as well can be damaged.
The primary object of the present invention is to reduce
the possibility of such damage by incorporating in the hydraulic
system a redundant arrangement of pumps and related filter units
and to constantly monitor performance to detect both failing
~decaying) and failure conditions in terms of pump and filter
efficiency, enabling remedial action to be timely applied.
Pnother object of the invention is to incorporate in the
- system a reserve unit which is automatically o2erated in the
event a failure is detected, while concurrently disabling the
failed unit. Another object of the invention is to create
warning signals in the event a near failure condition is
detectedO
10~76921
,, .
Specifically, it is an object of the invention to monitor
filter efficiency, activating a reserve pump and disabling the
active pump ~or pumps) in the event a threshhold of pump
l-'ailure is detected or in the event a predetermined level of
declining filter efficiency is detected. A further object of
the invention in this regard is to employ in redundant relat~on
two active pumps and a single reserve pump, together with
related filter units, such that in the event both active units
are sensed as being in a failed condition, the reserve unit
may be relied on for a limited time.
Other objects of the invention are to utilize a flow meter
to determine if a pump is either in a failing condition or has
failed; to sense the pressure drop across the filter by means
of differential pressure switches responsive to co~plete filter
failure or a failing (decaying~ filter condition: to enable the
failing or failed condition to be remediea by relying on a
reserve pump and filter unit; and to enable appropriate signals
to be created so that the operator of the classification yard
may be aware of the downstream circumstances.
~ reliable and efficient pump operation r~quires clean
hydraulic fluid. Contamination results in pump wear and filter
inef~iciency. According'y, another object of the invention is
to empioy exchange pumps for delivering the unfiltered hydraulic
fluid to exchange filter units prior to delivering the return
fluid to the reservoir tank which supplies the pressure pumps.
The exchange pumps and the exchange filters preferably
incorporate the redundant features imposed on the pressure pumps.
Since contamination particles break up when the fluid is
pumped and become smaller in size, it is possible for the clean
side of the reservoir to be contaminated with exceedingly fine
,
,'
~76~21
but nonetheless destructlve particles which are not captured by
the exchange filters. Accordingly, additional objects of the
invention are to utilize a silt pump and silt filter at the clean
side of the reservoir and to construct a rcservoir which both
eliminates turbulence and which accounts for highly efficient
transfer of fluid.
This application is a division of Canadian Application
Serial No. 265,003 filed November 5, 1976.
The invention as defined in the parent application
defined hereinabove provides in a hydraulic system where filtered
oil in a reservoir is to be delivered under pressure by a pressure
pump to a remote location and returned to the reservoir, reservoir
apparatus comprising a first tank for receiving the return oil;
a second tank for containing the oil to be delivered; a pres~ure
pump communicating with a pump inlet port in the second tank for
delivering oil in the second tank to the remote location; a return
conduit terminating at an opening in the first tank for feeding
return oil to the first tank; an exchange pump connected with an
exchange pump inlet in the first tank for transferring oil from
the first tank to the second tank through a transfer conduit
having an outlet in the second tank and having a filter interposed
between that outlet and the exchange pump; a plurality of baffles
interposed between the .~nlet port in the second tank and the
outlet in the second tank to remove turbulence from the transfer
oil entering the second tank; and a plurality of baffles in the
first tank interposed between the opening of the return conduit
-and the inlet to the exchange pump to remove turbulence from the
oil returned to the first tank.
On the other hand the present invention provides, ln a
10769Zl
rallroad classifi.cation yard having hydraulically operated retarders
infitslled at selected positions along the classification track
system, apparatus for furnishing hydraulic fluid to operate the
retarders and co~prising: (a) a plurality of motor-driven pumps,
at least one to be a normally active.pump and one to be a normally
inactive reserve pump; (b) a plurality of.filter units, one for
each pump, and through which the related pump moves fluid under
pressure; (c) means to sense the pressure drop across each filter
unit and to activate the reserve pump while deactivating the active
pump in the event the pressure drop exceeds a predetermined value
characterizing unacceptable filter efficiency; and (d) means
to sense the pressure drop across each filter unit and to generate
a signal when the pressure drop indicates a filter unit is
approaching unacceptable efficiency.
Furthermore the present invention may be considered to
provide, in a railroad classification yard having hydraulically
operated retarders installed at selected positions along the
classification track system, apparatus for furnishing hydraulic
fluid to.operate th-e retarders and comprising: (a) a plurality of
motor-driven pumps, at least one to be a normally act$ve pump and
one to be a normally inactive reserve pump; (b) a plurality of
filter units, one for each pump, and through which the related
pump moves fluid under pressure; (c) means to sense the pressure
drop across each filter unit and to activate the reserve pump
whlle deactivating the active pump in the event the pressure drop
exceeds a predetermined value characterizing unacceptable filter
efficiency; and (d) a flow meter to measure the flow of each pump
and to generate a signal when the measure indicates a pump is
approaching an unacceptable flow rate.
- 3a -
769Z~
In the drawing: .
Fig. 1 is a schematic view of a railroad
classification yard;
Fig. 2 is a plan view of an oil res~rvoir and
Figs. 3, 4 and 5 are sectional views thereof;
Figs. 6 and 7 are sche~.atic views of hydraulic
circuitry; and
Figs. 8 throush 13 are wiring dia~rams.
1~76~21
~ i~. 1 of the drawing is a schematic vie~ of a typical
retarder installation in a railroad classification yard. The
c:lassification tracks are identificd hy reference character 10.
C)n the up-stream side there is a so-called hump (not show?l)
where an operator at a console assigns the individual cars to
a selected one of the classification tracks. The car to be
classified acceleratcs down the grade of the hump, by gravity
fall, and is automatically switched to a particular classification
track.
The individual retarders are identified by reference
character 11. The retarder controls include cylinders, not
shown herein but of the character disclosed in patent Nos.
3227246 and 3809188. Hydraulic fluid for the cy~inders is
pressurized by accumulators 12 and these accumulators in turn
are charged by fluid under pressure furnished by a pump housing
15. The pressure line for charging the accumulat~rs is
identified by reference character 16. The exhaust fluid,
exhausted from the retarder cylinders after use, is returned
to the pump housing through the return conduit 17.
It will be appreciated from what is shown in Fig. 1 that
the hydraulic requirements are immense. Huge volumes of fluid
under pressure are circulated over a considerable distance,
resulting in pump ~?ear seldom encountered elsewhere. The chanees
~or contaminated hydraulic fluid are quite large. Consequently,
the factors of pump wear and likelihood of conta?nination
drastically effect reliability from the standpoint of sustained
operation over a protracted period of time. Under the present
invention, as will now be described, pump and filter performance
are constantly monitored, not only to give warning of a decline
in operating efficiency, but also to maintain aperating efficiency
--5--
7692~
in spite of a failcd pump and~or a failed filter unit.
As shown in Fig. 2, a reservoir 20, located at the pump
housing, is defined by a pair of adjacent tanks 21 and 22, the
construction of which will be described in more detail ~elow.
For the present, it is sufficient to point out that oil returned
from the retarder system is delivered to tank 21, filtered and
transferred to tank 22 which contains the supply of hydraulic
fluid for the pressure pumps.
The pressure pumps and associated filter units are shown
in Fig. 6. Three motor operated pumps lPl, lP2 and lP3 are
arranged in parallel with three associated filter units, lFl,
lF2 and lF3. In normal operation only two of the pumps will
be active, say pumps lPl and lP2, while the third pump and its
associated filter unit constitute a reserve unit.
Each pump delivers hydraulic fluid under pressure through
an outlet 40 and this outlet is branched at 41 and 42 to
deliver fluid under pressure to a pair of parallel filter
elements 43 and 44, coliectively constituting the filter unit.
In turn, the outlets of the filter elements are connected to
a common conduit 46 leading to a flow meter lFMl. The outlet
of each flow meter is connected to a common manifold 52
representing the pressure line 16 identified in Fig. l.
The filter elements are adapted to filter contaminants
of fifteen micron size.or larger.
Efficiency of each filter unit is constantly monitored or
sensed by a pair of differential pressure switches lF1-S1 and
lFl-52 and to this end the pressure switches are interposed in
a conduit 58 connected at its opposit ends respectively to the
downstream and upstream conduits 40 and 46.
-6-
,.
1~76~2~
~.s the filter elements become co~t~ninated by the filtered I -
particles, the pressure rises although the rate of delivery by
the pump will remain constant. Pressure switch lFl-Sl is
normally open but is pre-set to close when the pressure of the
hydraulic fluid being circulatcd rises to a value representative
of a marginal filter condition, that is, indicative of a
decaying filter of declining effectiveness, approaching a fully
inoperative condition, say a 30~ contamination level. l~en
switch lFl-Sl closes a warning signal is given, either by
lightiny a lamp or sounding a buzzer so that the operator in
the hump tower is warned of imminent filter failure.
Switch lFl-S2 on the other hand is pre-set to close ~hen
the pressure drop across the filter unit reaches an abnormally
high value indicative of an unacceptable filter conditio~, say
an 80% contamination level. ~hen switch lFl-52 closes, the
motor lMl for driving the associated pump is de-energized to
deactivate the pump.
It may be mentioned at this point that the ~onitoring
means for each pressure pump is identical and consequently to
avoid needless repetition the reference characters are only
selectively applied.
When a pump is deac~ivated because of a failed filter,
the reserve pump is placed on stream by energizing its motor
as will be explained.
-Each flow meter is equipped with three switches: one to
identify a failed flow meter tlFMl-s3)~ one to identify that
the pump is delivering fluid at a marginal rate, near failure
(lF~ Sl), and one to identify that the flow rate is so low
that the pump is deemed to be in a wholly ineffective state,
switch lFMl-S2.
.
.. .
. ., . - :
.. .
~0'769Z~
The flow meter is of known form and incorporates an
element (not shown) for measuring the rate of flow. ~f the
element itself fails, switch lFMl-S3 is actuated to preclude
needlessly servicing the pump. On the other hand if the metex
element which measures flow reflects a flow rate approaching'
an unacceptable pump efficiency level (say 80% effective)
switch lFMl-S1 closes in response thereto; and if the meter
element reflects a flow rate so low that the pump is deemed
in a failed condition (say 70~) switch lFMl-S2 closes in
response thereto. If either switch lFMl-53 or lFM1-S2 closes
in response to a condition deemed "failed", its pump is
disabled and the reserve pump is actuated. If switch lF~l-Sl
is actuated, a warning is given that the pump is in a near
fail state.
The exchange pump and filter system is similar, Pig. 7,
but only two pumping units, rather than three, are involved,
one for normal operation ~2Pl) and one (2P2) for emergency
in case the other fails. The exchange pump units are preferably
embodied in tandem pumps as 2Pl-~ and 2Pl-B having a common
shaft driven by one motor as 2~1.
Each pump as 2Pl withdraws from tank 21 the fluid returned
from the retarder cylinders. This unfiltered fluld is delivered
by a pair of separate conduits 60 and 61 first to a pair of
related filter units 2Fl and 2F2 (forty micron filter size) and
from thence to a filter unit 2F3 having two parallel filter
elements 63 and 64 ~fifteen micron size) connected by respective
conduits 65 and 66 to the outlets of the pumps 2Pl-A and 2Pl-B.
The fluid filtered at 2F3 is delivered by a conduit 68 to
a flow meter 2FMl and from thence to conduits 70 and 71 which
feed tank 22 at the pressure side of the pump housing.
- , ,
. .
: ,, : ' . '
~0769~
Ffficiency of the filter units 2Fl and 2F2 is monitored
b~ vacuum s~itches 2Fl-Sl and 2F2-Sl to detect a failing or
marginal condition defined ahove; likewise as to switch 2F3-S~
for filter unit ~F3. '~acuum s~itches 2~1-52, 2F2-S2 and 2F3-52
monitor the filters for a failed condition as defined ahove.
If one of the switches 2Fl-Sl, 2F2-Sl or 2F3-Sl is
actuated a warning is given and if one of the switches
2Fl-S2, 2F2-S2 or 2F3-S2 is actuated, the pumping unit 2Pl
is disabled and the other pumping unit 2P2 is automatically
placed on stream as will be explained.
The flow meter 2FMl monitors pump performance. It is
equipped with three switches: one to identify a failed flow
meter condition (switch 2FMl-S3), one to identify that the
pump is delivering fluid at a marginal rate, near failure
~2FMl-Sl) and one to identify that the flow rate is so low
the pump is deemed to be in a failed state, switch 2FMl-S2.
If the measuring element of the flow meter itself fails,
switch 2FMl-S3 is actuated to preclude needlessly servicing
the pump. If the flow meter reflects a flow rate approaching
an unacceptable pump efficiency level switch 2FMl-Sl closes in
response thereto; and if the meter reflects a flow rate so low
that pump 2Pl is deemed in a failed condition switch 2FMl-S2
closes in response thereto. If either switch 2FMl-S3 or
2FMl-S2 closes in response to a condition deemed ~failed",
- pump 2Pl is disabled and the reserve pump 2P2 is actuated.
If switch 2FMl-Sl is actuated, a warning is given that the
pump is in a near fail state.
~. , , , ,. : . ., : . , -
. . ' ,' '' , ~ '
1C~769Zl
The construction of the reservoir is shown in Figs. 2,
3, 4 and 5. Tank 21 receivcs from return conduit 17 the
unfiltered oil returned from the retarder cylinders. The
return oil is under a great deal of pressure and is preferabl~
- delivered to a submerqed diffuser 80, inside tank 21, Fig. 2.
The diffuser, constituting the outlet of return conduit 17,
has p~rforated hollow sleeves which separate the stream of
return fluid into numerous jet sprays within a diffuser
outlet chamber 81 of tank 21. Fnergy is thus removed.
The tank 21 is further divided into a plurality of
chambers 83, 84 and 85 hy serpentine haffles 86 ~hich reduce
turbulence, further reaucing the energy level. There are
three baffles and-as shown in Fig. 4 the me2ial one is
elevated ahove the bottom ofthe tank to induce a tortuous
flow between the chambers defined by the spaced baffles.
Chamber 85 of tank 21 containing the unfi]tered oil
is tapped by the conduits as 60 and 61 which feed the
exchange pump and filters. The inlets or entry ports of
these conauits are isolated from one another by dividers as
88, preventing the formation of interfering vortexes due to
the suction effect of the exchange pump leg.
The active exchange pump t2Pl or 2P7, Fig. 2) delivers
filtered oil through a transfer conduit 71 whieh terminates
in another diffuser 90 (outlet) submerged in the second or
pressure tank 22 which constitutes the reservoir for the
pressure pump leg. Tanl: 22 is also equipped with serpentine
baffles 91 to remove turbulence, and is also equipped with
div~der plates 92 which isolate the inlets to the three
conduits 93-1, 93-2 and 93-3, Fig. 2, which supply the
--10--
:
: ,
1~7692~
respective pressure pumps lPl, lP2 and lP3, Fig. 6~ again
for the purpose of preventing vortcx overlap.
In order to remove exceedingly fine particles, a silt
or slurry pump circuit is employed. This circuit or leg
comprises a pu~p lP4, Fig. 2, and related filter unit lF4
~three micron size), Fiqs. 2 and 6. The silt pump withdraws
filtered oil from tank 22 and returns it to tan'- 22 through
conduit 97 as shown in Fig. 2.
To maintain a constant interchange between filtered and
unfiltered oil, overf~ow pipes 95 are positioned to tap oil
at level L2 to tank 22, returning filtered oil to tank 21
having a lower level Ll. The different levels are a
manifestation of the requirement that the exchange pump must
deliver oil at a rate qreater than the rate of extraction by
the pressure pumps.
`--1 1-- .
. ~
.
,.
- 1~769Zl
ELECTRIC~L CONTROL
A. NO~E MODE:
The motor-operated pump control po~er source ~1, Fig. 8,
is connected to hand-operated 3-position and 3-pole rotary
selector switch E2. This selector switch has three functions:
Local, Off and Remote. Local position is primarily used for
pumping system start up and maintenance. The Off position is
used to remove all electrical control power from the pumping
station. Remote position is used to operate the pumping
station from any convenient location.
With switch E2 on Remote position, close switch E3:
energize control relay coil E4; relay contact E5 closes.
Control current flows from power source El through selector
switch E2, relay contact E5, normally closed rela~ contacts
E6, E7 and E8, selector switch E9 (exchange pump standby
selector switch, select any one of two positions) circuit
brea~er auxiliary contact E10 (hand operate), and normally
closed control relay contacts Ell, E12, E13, E14 and E15.
Exchange pump motor starter thermal overload contacts may be
inserted. ~t this point in time, pump motor starter coil F.l9
is energized to close the main motor contactor E20. The
motor-operated exchange pump 2Pl begins to operate.
Normally closed auxiliary contact E23 of main contactor
E20 and time delay contact E24 are opened, preventing standby
motor-operated exchange pump 2P2 from operating.
Control relay coil E25 is enerqized. The contacts of this
relay, E25, Fig. 10, are used to control monitoring indicating
lights.
Time delay rela~ coil E26 is energized. Delay contact
E27 will close at a pre-determined time. The purpose of this
-12-
. ': ' ~ '' ' : , '
. . ,
., , ~ .
.
769Zl
relay is to prevent the failure detecting circuits from
operating until pump speed and hydraulic oil f]ow are
normalized. Time delay coil E28 is also energi~ea.
At a pre-determinea time, relay contacts E2~ and E29
will close. Relay contact E29 is shown in Fig. 11 ana so
are the other relays, contacts and switches now to be described.
Since remote control relay coil E4 is already energized,
relay contact E30 is also closed. Control current flo~7s from
control po~er E31 through time delay relav contact E~9, remote
control contact E30, control relay contact E32 ana selector
switch E33. The latter is the pressure pump standby selector,
positioned in any one of three positions. Assume pOsition 1 is
selected: control current continues through circuit breaker
auxiliary contact E34 (hand operate), and normally closed
control relay contact E35, E36 and E37. Pressure pump motor
starter thermal overload contacts may be inserted.
Pump motor starter coil E41 is energized and closes main
contactor E42, whercupon motor-operated pressure pump lPl
begins to operate.
At the same time control relay coils E44 and F.45 are
energized: open normally closed contact E46 to de-energize
control relay coil E47, and through relay contact E48 energize
the unloader solenoid valve E49. The unloader is shown
schematically in Fig. 6. In this manner, there will be zero
load on the pressure pump whenever there is a requirçment for
the pump to start up.
At a pre-determined time, delay contact E50 is closed,
which allows the pressure system to cycle automatically from
the unloading mode (solenoid valve E49 energized) to the load-
ing mode where solenoid valve ESl is energized.
-13-
'
' ' ~ . '
.
:
1(~7692~
Time delay contact ES2 will close at a pre-determined
time. This delay closure will prevent the failure detccting
circuits from operating until pump speed and hydraulic oil
flow are normalized.
Motor-operated silt pump lP4 will start to operate at
the same time as pressure pump lPl. Thus, control current
flows through Fircuit breaker auxiliary contact E53 and
control relay contact E~; starter coil E5~ is energiæed,
starting the silt pump.
~hile pressure pump lPl is in operation, time delay
relay coil E59 is energized. After a pre-determined time
delay, relay contact E60 is closed which permits control
current to energize the second pressure pump lP2. Time
delay relay coil E62 and its contact E63 are used to prevent
operation of the standby pressure pump lP3. The reason for
allo~ting only one pump to start at a time, except the silt
pump, is to ~eep the starting current demand low.
In normal operation of the system, one of the pressure
pumps is de-energized as a standby. To accomplish this,
normally closed auxiliary contacts E64 and E65 are held open
due to themain contactor coils being energized.
Summary of the normal mode operation is as f~llows:
a) Selector switch E2 on Remote position;
b) Standby exchange pump selector switch E9 in
one of two positions. ~For purpose of
explanation, position 2P2 is selected, mean-
ing exchange pump 2P2 is on standby.
~: :
: ... ., : .
.. . . . .. . .
.' : ' , ,,' ' ' , ~ :
:. ', . : ' : ~'
.. . . .............. .. . .
: : . :
10~692~
c) Standby pressure pump selector switch in
one of three positions. (For purpose of
explanation, position rlo. 1 is selected
placing pump lP3 on reserve)
d) Turn switch E3 to On position.
e) ~xchange pump 2Pl operates immediately;
standby pump 2P2 remains inoperative.
f) After a time delay, pressure pump lPl
and silt pump lP4 automatically begin
to operate; pressure pump lP2 and
standby pressure pump lP3 remain
inoperative.
g) After another time delay, pressure pump
lP2 begins to operate; standby pressure
pump 1~3 remains inoperative.
h) Loading and unloading cycles are
automatically controlled by pressure
switches E67 and E68. Switch E67 opens
above 800 psi and switch E68 closes
below 700 psi.
i) Normally, one exchange pump, two pressure
pumps and th~e silt pump are always in
operation. In the event of malfunction,
the faulty pump will be disabled and the
standby pump will be automatically set
in operation.
1{~769Z~ -
B. W~RNI~G MODE:
Typical ~arnina and failure modcs ~till be descrihed in
detail for the exchanae pumps 2Pl and ~P2, Fig. 10. I~'arninq
circuits of the same order are employed for the pressure pumn.
lPl, lP2 and lP3, Fig. 13, but will nnt be described in detail
since they can be traced on the basis of the detailed explanation
now to ~e given for the exchanqe pumps.
Contacts ~25'of relay E25 are closed, Fiq. 8. r~hen
filter-operated s~itch 2Fl-Sl, Fig. 10 (and see Fiq. 7) detects
a pre-set limit of warning contamination in the leg of pumo 2Pl,
switch 2Fl-Sl closes, lighting lamp ~70. Lamo E70 may be at
the pump house. Relay coil 71 i.s enersized for remote warning
indication which may be located in the hump tower.
lqarning switches for flow meter indication of a failing
exchange pump, sw.itch 2FM-Sl for pump 2Pl, Fiq, 10 (and see
Fig. 7) establish warnings. The warning circuits do not cause
a shift to the standby exchange pump, deemed to be pump 2P2.
The same warninas for filter conta~ination and failinn nump
are imposed on the standby exchange pump 2P2, Fig. 8, the silt
pump lP4, Fig. 11, and the pressure pumps as shown in Fiq. 8.
Thus e~change oump 2r2, silt pump IP4 and each of the three
nressure numps areassociated with a filter conta~ination
warninq s~itch (as lFl-Sl for oressure pump IPl, Fiq. 13) and
a failing pump ~-arning switch (as lF~l-Sl for oressure pump
IPl, Fig. 13).
C. FAILUR~ MODF:
When filter-onerated switch 2Fl-52~ Fiq. 8, cetects a
pre-set limit deemed to be a filter failure, the switch closes,
-16-
.
, '. ' . : ' "' - " ~ ' .: ''
.: . : ~ : .:
1~769~
energizing control relay coil ~73 which closes relay (holding)
contacts E74, Fia. 8, and F75, Fig 10. The related uarninq
lamp is thus held lit. ~elay contact ~]1 o~ens, Fig. 8. ~he
main contactor coil Elq is de-energized and the e~change num~
2nl ~ill be disahled.
Since main contactor coil ~19 is de-energizea as a result
of contacts Ell openina upon energizing relay E73, auxiliary
contact E23, Fig. 8, of main ~otor contactor returns to its
normal closed position, causing standbv motor-overated e~:chanqe
pum~ 2P2 to operate. ~olding contact E74 k~eps rela~ 73
energized and nrevents pump 2Pl from being restarted until
after the highly contaminated ~ilter 2~1, Fia. 7, in the leg
of pump 2Pl is replaced therehv to de-energize relay coil ~73.
Rela~ contact E75r Fia. 10, is used to liqht ~he related
failuxe identification lamP and for rcmote warnina indication.
The other filter failure switch 2F2-~2, Eia. 7, for
exchanqe ~ump 2Pl operates in the same ~anner, equally true
of the other exchange pumD 2P2.
In the event of pum~ failure tdetected at the flo~r meter)
s~ritch 2FMl-S2 is closed, Figs. 7 and 8, energizina relav E78
and closing contacts E79 (holding) and E80. Lamp F81 li~hts
for local warnina. Contact~14 controlled ~y relay ~78 opens,
de-energizing coil rl9 tQ stop pump 2Pl. Cont~ct ~23 closes,
placi~g the stand~y nu~ 2~2 in o~eration. ~?oldinq contact E74
prevents ?ump 2Pl from being restarted (that is, coil E78 is
held energized to hold contacts ~14 open) until it is repaired
or replaced; reset by switch ~6.
If the flow meter fails, s~itch 2~ 3 ~los~s (see ~i~s.
7 and 8) energizina relay F84. Contacts ~15 o~en, pum~ 2~1
3n is disabled and lamp E85 $s lit.
-17-
:. ~
~(~769Z~
~ hesc operations also appl~, to the pressure pump legs in
the filtered tan]~ 22: failed filter s~!itch lFl-S2; failed
, pump switch lEMl-S2; and failed flo~s mcter s~!itch lFMl~S3.
~ en the fail~re has been corrected in the ].eg reprcsented
by pump 2~1, selector s~;itch F9, Fig. 8, is repositioned to
posi.tion '.lo. 2 to place pumn 2Pl in automatic standby. r~eset
st-itch ~96 is actuated to dro~ out relay R73, e~tinguishing
the indicator lam~. ~Jith switch E9 in position ~o. 2, relav
El9 ~ill be energized to start ~otor 2?Sl only in the event
pumn 2P2 is disabled because of a failure, resulting in a
closure of contacts ~97 normally open so lonq as motor 2rl2
is operating.
D SYS?E~l Ft~ILVRR r~DF ()PFI~IO.'~:
~ side from a poter failure, the follo~.~ing conditions
are consi.dered as an entire system failure as sho~m in Fig. 10:
a) tt~o e~change pum~as failed (contacts 2~.1 and 2~2);
b) three pressure pumPs failed (contacts lRl, lK2 an~
lY~3); or
c) yard pressure failed (see switch PS-3, Fi~. Il)
meaning relay 1~,~16 is de-energized, opening contacts
lKlG.
' -18-
.
:
.- ' ~ ,. - ,:.
. " ,:
10769Zl
. SU~ Y OF ~ r~ Ar7D FATL~D MO~E~:
A11 pumPs (ressure, e~changer and silt or slurrv)
deliver through a filter havin~ a sensin~ means in the for~
of a pressure differential switch to detect ~oth a filter
condition a~proachinq unaccepta~le contamination (warninq)
and a comnletely unacceptable level of filter contaminatiOn.
T~e latter is dee~ed a filter failure. ~hese conditions
have been described in detail for the e~change- ~Ump svstem
and can be traced for the pressurc pumps.
In the event a failing pumn, detected at the flow meter,
warning is also given in the e~change pumP and pressure DUmp
leqs.
In the instance of the silt pt~p IP4, it can also he
seen in Fia. 13 there is a filter onerated s~-itch lF4-Sl for
~,larning of a near failure an~ as shown in Fig. 11 there is a
second filter s-ritch lPA-S2 for sensing a failed filter in the
silt pump leg. If this latter switch is operated, relay lR14 is
energized; its contacts 1~13, Fig. 13, are closed to light a lamP.
There is no standby silt pump; nor does the silt pump leg
include means to detect either a failing pump or a complete
~ump failuxe. On the other hand, if a filter for the operative
exchange pump fails ~e.a. 2Pl) or if its motor or 1O~q-meter
fails:
a) one of four relays is energized, Fiq. 8:
2K3, 2~4, 2R6 or 2X7;
h) the related relay contacts open to disahle
the pump motor, Pig, 8;
c) contacts E23~open when pump motor 2MI is
energized) revert to closed position, ~lacing
the motor of pump 2D2 in operation;
--19--
.
7~;9;~
d) the failed con~ition is corrected; and
e) s~iritch ~9 is set to ~.lo. 2 position, readyin~
pwnp 2Pl as the stand~v.
Rs for the pressure pum~ sv~tem i.n a faile~ mode, and
assuming se]ector s~,ritch P9 (Fi~. 11) set to positi.on .~To. 1
(mhich assi~ns pumr IP3 the standhy role~ motor relay cont~cts
~64 ana E64' ~pump motor lrtl~ are open as ].ona as the motor
for pump lP]. is energi~ed, and relav contacts ~65 (motor for
pum~ lP2)are also onen.
.~ No~r if any one of the ~ailure mocle s-ritches in the ].eo
of pu~ 1 is actuatcd (lPl-~?. or lF~1-57 or l~Ml-~3) an~
with contacts ~60 and ~63 closed:
a) relay lI'4j lY~5 or lK6 is ener~ized and its
contacts o~en;
h) motor relay lMl (~41) is there~y de-enerqized
and its contacts are reversed (e.. contacts
E64 and ~64' close);
c) contacts P65 are open because it is assumed
there is no failure in the leg of pump lP2
but since motor relav lr~l is de-energized
its contacts F64 close, placinq pump lP3 on stream;
d) concurrentlv contacts ~64' close an~ the contacts
~66 of the motor relav for the motor of pumn lP3
open, so that
e) pumps lP2 and lr3 are on stream.
~he failure in the leg of pump lPl is remeAi.ed and the
selector s-ritch may be set to No. 2 position, which readies
pump lP2 to he the standby.
-20-
: ~, ' :, ' ' - .,
' " ' ' ' '
~ 769Zl
When a predetermincd high temperature ~sa~ 160F) is
reached either in the unfiltered tank 21 or filtered tank 22
a related thermal switch F7h (Fiq. 8) located in tank 21 (return
oil) or X77 (Fia. 11) located in tan~ 2~ is closecl to enerni~
relay coil ~88 or ~89, openincJ normallv closed contact ~6 or E8,
Fig. 8, to disa~]e the exchange pumps. Wonetheless, the pressure
~ums will re~a;n in operation until a low oil 5witch E90, Fig. 11,
located in tank 22, is activated to energize reiav coil ~91,
openirg relav contact F3?, Fiq. 11. A low oil switch F90 is
also located in the unfiltered tank 21, Fig~ 8. From the time
a high temperature condition is detected urtil the entire system
is shut down is approximately two minutes.
If desired, heat exchanae fans may be used to keep the
oil cool h~lt nonetheless the high temperature and low oil sensors
will be used.
When a precletermined low te~oerature (sav-20F) is reached
either in the unfilterecl tan~ or filtered tank, switch ~92 or
~93, Fig. 8, is closed to eneraize relay coil E94, Piq. 8,
openina relay contacts F98 (Fia. 8) and F99 (Fig. 11) to
de-activate the filter and flow-meter fault monitoring circuits.
T~is avoi~s faulty indications due to the viscosity of the oil
at low te~perature. The exchanae and pressure ~um~s wil] remain
in oparation; a warninq light is lit locallv and remotely.
The lamp circuitry shotm in Fiqs. 10 and 13 mav ~e
extended to siqnal kich ancl low t~mperatures, low oi] and oil
over-fill.
The unloader, FiqO 6~ is employecl to allo~ the pressure
pumos to start aaain~t a no-load condition a.s already explained.
At the commencement of start-u~, contacts ~46, F~a. 11, open
-21-
~C~7692~
when relay P45 .is energized, de-energi~ing re~av ~7 and al~.owin~
~ts colltact~ ~4~ to revext to the nor~].ly c]os~d condition. As
a consc~uence the 4-way unloader va].ve i.~ opened and there is
no resistance to the pressure pum~s.
S~!itch ~58 is closed (closed below 700 p5i) 50 ~.~hen the
timc delay contActs ESO close, rela~ ~47 is ener~ized and its
contacts reverse, energizing solenoid valve F51 to place the
4-way valve in the system loading moae.
It will be seen from the foregoing that oil, used to
operate the retarders, is returned to tank 21. Turbulence
is removed by the baffles 86 prior to the return oil entering
the inlet ports which communicate with th~ exchange pump.
The exchange pump 12Pl or 2P2) sends the oil through a
filter (see Fig. 2) and the filtered oil is delivered to an
outlet in the second tank hy means of a transfer conduit 71.
Turbulence of oil in the second tank is removed by
baffles 91. Very fine particles of contaminant in the oil,
not removed by the exchange pump filters, are removed by a
filter lF4 servïced by a pump lP4, both interposed in a
recirculating conduit 97, Fig. 2.
Oil is pumped from tank 22 by a plurality of activated
pressure pumps. To prevent vortex overlap, the inlets to the
pressure pumps are isolated from one another by dividers 92,
Fig. 2. The same arrangement is employed (dividers 88) for
the e~change pump inlets. . .
If a pressure pump ~or exchange pump) fails, the reserve
pump is activated and the failed pump is deactivated,
automatically. The same automatic switch-over occurs in the
~nstance of a failed flow meter or failed filter in a
-22-
'.' ' , '' , , '' ' ;,: . ' ' ' :
.
:: .
10769Zl
pressure pump leg or an exchange pump leq.
Such automatic corrections occur as an incident to
operation of a sensing means as switch lFMl-52, Fiq. 6,
which senses flow rate; switch lF~ 3 ~hich detects failure
of the flow meter measuring element; and s~itch lF1-S2 which
senses pressure drop across the related filter.
Jf a failed condition is sensed, a relay is energized;
such as relay ~73, Fiq. 8, and a s7arninq is given, e.g. a lamo
is lit. .~t the same time, corresponding motor relay contacts
such as contacts E20, Fig. 9, are opened to disable the pump
and other motor relay contacts are closed to activate the
reserve pump.
r~hen a sensing means detects a pumn or filter is nearing
failure, a warning is given.
~ eferring to Figs. 10 and lOA, any warning of approaching
failure i5 manifest in a lamp as ~70 being lit locally at the
pump house (Fig. 10), and remotely as well tFig. lOA) as for
instance by a lamp P102 at the control tower where the yard
operator is in charqe.
The remote signals,-Fig. lOA, include a lamp E103
identified ~i~h "system failed" and another lamD E104
signifying the system is in a normal mode.
Lamp E103 will be lit ~nd E104 extinguished) as long
as relay E106, Fig. lO, is de-energized; lamp E104 will be
lit ~and E103 extinguished) if relay E106 is enerqized.
Thus, if the yard pressure is inade~uate, contacts
lX16, Fig. 10, will remain open and lamp E103 will remain lit.
If both exchanqe pumps fail, both sets of contacts E108
and E109, Fig. 10, are open; relay E106 is de-energized and
lamp E103 is thereunon lit to show a failed svstem; contra if
-23-
-` 107692~
one exchange pump is workina in the normal mode.
If all three pressure pumps fail, the circuit for relay
Elt)6 is open at lKl~ lK3, Fig. 10, and lamp E103 is lit;
~ contra if one pressure pump is in working order.
-24-
':' ' :
.- . . : . :: : ~ :
:. : : : . : .
: ~ . ' ~. ' .,,: ,, ~ ' '
