Note: Descriptions are shown in the official language in which they were submitted.
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AN APPARATUS FOR AUTOMATICALLY WATER CHARGING A CENTRIFUGAL
FIRE PUMP
,
In rural areas, the fire figh-ting equipment is sometimes
less than desirable. It has therefore become necessary for com- !
panies owning grain elevators or the like to establish their own
fire fighting equipment. Frequently, centrifugal or turbine fire
pumps are provided on site to pump water from an underground '
water supply onto the area experiencing the fire. The use of
centrifugal pumps does create several problems since centrifugal
pumps do not have the ability to establish a wet suction from
the stored water supply when the storage tank is below pump level.
Since the pump must have a solid charge of water before it is
operated, some means of establishing a dependable prime must be `I
provided since it is destructive to high-speed turbines to even
operate only a few revolutions without water. If the water supply
was located above the pump, water would be continually supplied
to the pump but most locations do not have sufficient grade to
position the large water storage tank above the pump. Addition-
ally, the continual presence of water within the pump is quite
harmful to the pump since many rural areas have ex~remely corro-
sive water supplies. ;'
Several current methods of prlming centrifugal pumps are
presently being employed. Among the most common methods are:
(lj positive head or flooded suc~ion; (2) priming rom draft;
(3) hand operated vacuum pump ejector priming; (4) electric pump
priming; and (5) retention of water at pump level by a foot valve.
None of the above methods function without the aid of manual
operation and someone must be on the site when the fire pump is
operated.
Therefore it is a principal object of the invention to
provide an automatic means for positively charging a centrifugal
water pump wherein the water supply is located below the pump~
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3~
A still further ohject of the invention is to provide an
apparatus for positively charging a centriugal pump which allows
the pump to be operated only when the pump has sufficient water
therein so as to prevent damage thereto.
A still further object of the invention is to proviae an
automatic vacuum and water charge system for a positive water
pump prime prior to the water pump being actuated.
A still further object of the invention is to provide an
apparatus for positively charging a centrifugal fire pump includ-
ing means for deactivating the fire pump if the prime is lost.
A still further object of the invention is to provide an~automatic fire protection system which is ideally suited for
rural areas. ¦
These and other objects will be apparent to those skilled ,~
in the art. ;
This invention consists in the construction, arrange-
ments and combination of the various parts of the device, whereby
the objects contemplated are attained as hereinafter more fully
set forth, specifically pointed out in the claims, and illus-
trated in the accompanying drawings, in which:
Figure 1 is a schematic of the system:
Figure 2 is a partial schematic of the system:
Figure 3 is a schematic view illustrating the prime
water raising the float within the sight glass:
Figure 4 is a schematic of the electrical circuitry of
the invention when in an inoperative condition: '
' Figure 5 is a schematic,view similar to Figure 3 except
that the water level within the sight glass has risen from that
of Figure 3 to activate the system:
Figure 6 is a schematic of the electrical circuitry of
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the invention when in an actuated position:
Figure 7 is a view similar to that of E~igures 3 and 5illustrating the water level initially rising within the pump; and
Figur~ 8 is a schematic view of the float stop and reed
switch.
The numeral 10 refers to a conventional magnetic contactor
pump motor operatively connected to a conventional centrifugal
pump 12 having a suction line 14 extending therefrom to a source
of water 16 such as an underground supply tank or the like. It is
recommended that a stored water supply be used and that a sub-
merged cast concrete tank be employed with the bottom thereof no
lower than 14 feet and having the top thereof covered with 24
inches to 36 lnches of dirt to prevent freezing. It is also
recommended that the top of the tank be provided with a pre-
stressed portion to allow truck traffic over the tank. The suc-
tion pipe 14 is kept within six inches of the bottom of the tank
to allow full usage of the stored water. Ordinarily in older
facilities, the tank will be located just outside of the elevator
office with the pump 12 being located in a concrete room in the
basement of the elevator.
Discharge line 18 extends from the pump 12 to the area
to be protected and has a plurality of sprinklers 20 provided
thereon adapted to spray or sprinkle water onto the area in the
event that a fire should occur. A conventional alarm system 19
including a fire switch 80 is located in the area to be protected
and it is operatively connected to a control panel 21. Control
panel 21 is electrically connected to a conventional vacuum pump
26 including a motor 27. Pump 26 has a vacuum line 23 extending
therefrom to the upper portion of a transparent sight glass 22.
Vacuum line 24 extends from the lower portion of the sight glass
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22 to pump 12 and is in communication with the interior thereof.
Generally speaking, actuation of the vacuum pump 26 causes a
vacuum to be created in line 23, sight glass 22, line 24, pump
12 and line 14 so that water will be drawn upwardly through line
14, into pump 12, through line 24 and into the interior of sight
glass 22 as will be described in more detail hereinafter.
Referring now to the circuitry of the invention, the
numeral 28 refers generally to a source of 120 volt alternating
current including leads 30 and 32. Lead 32 is connected to the
vacuum pump motor 27 by leads 34 and 35. Lead 30 is connected to
switch 37 of transfer relay 36 by lead 38. Contact 42 of relay
36 is connected to relay 44 by lead 46. Relay 44 includes switch
47 and contacts 48 and 50. Contact 50 is electrically connected
to the motor 10 by lead 52. Switch 47 and motor 10 are electri-
cally connected to the source of alternating current as illus-
trated in the drawings. As seen in the drawings, relay 44 is
connected to the lead 34.
The numeral 54 refers to a transformer electrically
connected to rectifier 56. Rectifier 56 is connected to relay
36 by lead 60. Rectifier 56 also has a lead 62 extending there-
from which is connected to lead 98. The numerals 69 and 71 reer
to a resistor and capacitor which interconnect leads 60 and 62
as illustrated in the drawings.
Lead 68 is connected to relay 70 including switch 72 and
contacts 74 and 76. Lead 78 is connected to relay 70. Leads 68
and 70 are connected to the fire switch 80 of fire alarm 19.
Contact 81 of test switch 82 is connected to lead 86 which con-
nects contact 76 and motor 27. Contact 87 of switch 82 is con-
nected to contact 40 of switch 37 by lead 88. Contact 87 is
connected to lead 88 by lead 9~. Relay 36 is connected to float
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switch 94 by lead 96. Lead 98 connects contact 100 of switch
94 with flow switch 102. Lead 110 connects contact 106 of
switch 94 with contact 104 of switch 102 as seen in the drawings.
Sight glass 22 is provided with an upstanding tube 112
having a stop 116 at the upper end thereof. A noxmally open
magnetically sensitive reed switch (float switch 94) is positioned
in the upper end of the tube 112. 1eads 96 and 98 are connected
to the read switch and extend downwardly through the interior of
the tube 112. Float 114 slidably embraces tube 112 and rises and
falls with the water level within sight glass 22. Float 114 has
magnets cast into the interior of the float cavity. Float 114 is
adapted to close the float switch 94 when in its upper most posi-
tion. As the float is guided up the tube 112 by the rising water
level within sight glass 22, the magnets within the float 114 act
on the reed switch 94 and cause it to close the circuit. Closing
of the switch 9~ causes the relay 36 to deactivate the vacuum
pump motor and to activate the fire pump as will he described
in more detail hereinafter.
In the stand-ready state of Figure 4, no prime water
is contained in the sight glass 22 or i~ the pump 12. The relays
36, 44 and 70 are unenergized at this time. Ie alarm system 19
senses a condition meriting sprinkler water, the first switch 80
energizes relay 70. Energizing of relay 70 closes -the contacts
on the relay which causes the vacuum pump 27 to be energized or
started to establish a vacuum in the sight glass 22, line 24,
pump 12 and line 14. As air is exhausted from the sight glass 22,
prime water will enter the pump turbine from the line 14 and will
proceed to the sight glass by means of line 24. The water enters
the sight glass at the lower end thereof through small orifice
outlets provided ~herein. As the water rises in le~el in the
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sight glass 22, the magnetic 1Oat 114 moves upwardly on the pipe
or ~ube 112 towards the upper stop position (llh~. As float
114 reaches stop 116, the magnets in the float 114 cause the
reed switch 94 to close which energizes the transfer relay 36.
It should be noted that the reed switch 94 is enclosed within
the tube 112 and is isolated from water. The sight glass is then
approximately one-half full of prime water which indicates a
solid charge above turbine level. The closing of relay 36 breaks
the circuit to vacuum pump 27 and causes the vacuum pump 27 to be
deactivatedO As relay 36 closes, it energizes ~he pump motor lO.
This brings the fire pump on line while the vacuum pump is idle.
As the fire pump begins to establish a head o water in the
sprinkler system, the suction o the pump at the suction side
is strong enough to pull the one-half full sight glass down to
empty while pumping. The float 114 naturally follows the water
level and very quickly is restin~ at the bottom of the tube 112
to open the reed switch 9~. However, since there is a high
pressure discharge, the flow switch 102 is closed sensing the
pressure which keeps the relay 36 in a closed attitude so that
the pump is self-monitoring. If during the cours of pumping the
prime is lost (low waterr etc.), the flow switch 102 senses no
flow and opens the circuit which deactivates or drops the relay
36 to deactivate the fire pump. When relay 36 is deactivated,
the vacuum circuit is re-established and th~ cycle is restarted
towards a Eull prime. Thus it can be seen that the first pump
cannot run without a full prime charge.
Test switch 82 is provided for in-pump room periodical
testing. It is also suggested that a control switch be provided
under lock and key mounted in the master breaker on the outside
of the elevator for pump control in the event of a serious fire
when the fire alarm might lose control or for safety reasons
not to enter the plant.
Thus it can be seen that a novel apparatus has been
provided for automatically water char~ing a centrifugal fire
p .p which accomp1ishes at 1ea~t all of its stated objectives.
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