Note: Descriptions are shown in the official language in which they were submitted.
`7~
SPECIFIC~TION
This invention relates to apparatus for controlling
liquid level in a resexvoir, and is more particularly con-
cerned with apparatus of this kind which will operate
automatically, and to special advan-tage in municipal ~ater
systems.
Municipal water systems are generally equipped with
elevated tanks or reservoirs to maintain substantially
constant supply line pressure. Such reservoirs are liable
to fairly wide range of water demand which may vary widely
during certain periods of a daily cycle or unusual demands
such as during a fire, and there may be intervals of very
low demand cr even stagnation such as during nighttime hours.
A simple pump control for such reservoirs employs a float,
but in areas where icing is a problem the float control is
unsatisfactory due to icing in freezing weather. Some fairly
sophisticated arrangements have been employed which do not
use a float, but so far as I am aware, the prior arrangements
have suffered from one or more of the problems and dis-
advantages such as diffieulties in attaining and maintaining
satisfactory adjustment, erratic and undependable behavior
under various conditions such as changes in temperature, the
necessity for expensive electrical monitoring, liability
to be affected by water leakage, difficulty in coping with
icing, problems with electrical switches, and the like.
Telephone wires are frequency rented for conveying the water
level information to the pumping stations, which service is
costly and subject to failure. The same holds true when
radio signals are used. Therefore, in many localities
reliance is still on manual maintenance of the pumps, turning
on sufficient pumps to keep up with the demand, and cutting
; baek others before they overflow, even during ernergencies
sueh as in case of fire.
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.
~LZ'7261~i
~n important object of the invention is to provide
new and improved apparatus for controlling liquid level in
reservoirs and which will overcome the disadvantages,
deficienci.es, inefficiencies and problems inherent in prior
apparatus and practices.
The invention provides apparatus for controlling
liquid level in a reservoir, comprisiny primar~ means for
automatically controlling operation of xeservoir replenishing
means for normally maintaining an upper liquid level within
a narrow fluctuation range in the reservoir during peak and
minimum demand intervals, selectively operable level drop
controlling means which is auxiliary to said primary means,
for controlliny said primary means to permit a level drop
substantially below the low end of said fluctuation range of
said upper liquid level in the reservoir and then automatic
operation of said primary means to return the liquid level
to said upper level whereby to prevent stagnation of water
in the reservoir during minimum demand intervals or to place
the reservoir in a standby condition.
The invention also provides a method of controlling
liquid level in a reservoir comprising effecting primary
control of operation of reservoir replenishing means for
normally maintaining an upper liquid level within a narrow
fluctuation range in the reservoir during peak and minimum
demand intervals, selectively operating level drop controlling
means to modify operation of said reservoir replenishing
means for a selected interval of time and thereby effecting
controlled level drop substantially below the lower end of
said narrow fluctuation range, then effecting operatlon of
the reservoir replenishing means to return the liquid level
to said upper level; and after said time interval disabling
operation of said level drop controlling means and effecting
--2--
diaphragm drives the transmission liquid through the metering tube to said
controlling means.
The invention further provides in apparatus for automatically
controlling liquid level in a reservoir in accordance with head pressure in
a main leading from the reservoir: means for mon:itoring the head pressure
in the main, a pivotally supported balance beam, balance weight means
carried by said beam and adapted to be adjusted longitudinally relative to
the beam to a setting determinative of a desired liquid level to be main-
tained in the reservoir by operation of the apparatus, means adjacent to
one end of the beam responsive to said monitoring means and cooperative with
the balance weight means for controlling the pivotal attitude of the beam
substantially in agreement with monitored head pressure, within a range
wherein the beam is in a first pivotal position when the monitored head
pressure is indicative of said desired liquid level and in a second pivotal
position when the head pressure is indicative of a liquid level in the
reservoir lower than said desired level, means at the opposite end of said
beam for controlling operation of liquid supply means for the reservoir in
accordance with the pivotal attitude of the beam as controlled by said
balance weight means and said monitor-responsive means, so that the liquid
supply means will remain inactive in said first position of the beam and will
be operated in said second position of the beam to supply the reservoir,
said monitoring means comprising a pressure-sensitive hydraulic cell having
a chamber in which said head pressure from the main is received~ a reversible
diaphragm dividing said chamber into sub-chambers one of which sub-chambers
is connected with said main to receive head pressure from ~he main, the
other of said sub-chambers being separated from the head pressure sub-c~amber
by said reversible diaphragm and being in metered communication with said
beam controlling means, and pressure transmitting fluid in said other of
said sub-chambers and substantially filling the metered communication with
said beam controlling means, said diaphragm being reversible from a position
wherein it occupies most of ~he space within said head pressure sub-chamber
-4a-
normal operation of the reservoir replenishing means to
maintain said upper liquid level within said narrow fluctuation
range, whereby to prevent stagnation oE water in -the reservoir
during minimum demand intervals or to place the reservoir in
a standby condition, during said -time in-terval.
The invention further provides in apparatus for
automatically controlling liquid level in a reservoir in
accordance with head pressure in a main leading from the
reservoir means for monitoring the head pressure in the
main, a support,a balance beam, pivot means pivo-tally mounting
said balance beam on a longitudinal axis adjacent to one
of its ends to said support such that a short tail portion
of the beam projects beyond one sicle of the pivot means and a
substantially longer beam lever portion projects beyond the
opposite side of said pivot means, balance weight means
carried by said beam and normally biasing the beam to depress
said longer beam lever portion and raise said tail portion,
said weight means being adapted to be adjusted longitudinally
relative to the beam to a setting determinative of a desired
liquid level to be maintained in -the reservoir by operation of
the apparatus, a hydraulic actuator fixedly mounted
in position on said support and having movable means connecting
said actuator to said tail portion, said actuator operating
responsive to monitored head pressure to apply reaction
pressure between said support and said tail portion whereby
to depress said tail portion and counteract the bias of said
balance weight means to raise said longer beam lever portion
substantially in agreement with monitored head pressure,
said actuator permitting said tail portion to rise and said
lever portion to drop when the monitored head pressure is
indicative of a liquid level in the reservoir lower than said
desired liquid level; and means at the distal end portion of
~ ~7~
said longer beam lever portion ~or controlling opera-tion of
li~uid supply means for the reservoir in accordance with the
pivotal attitude of the beam as controlled by said balance
weight means and said hydraulic ac-tuator, so tha-t ~he liqwi~
supply means will remain inactive in said upper position o
the lever portion and will be operated in said lower positlon
of the lever portion to supply the reservoir.
The invention also provides in apparatus :Eor con-
trolling liquid level in a reservoir in accordance with head
pressure in a main leading from the reservoir: liquid suppl~
means for the reservoir, means for operating said supply
MeanS on demand for replenishing the reservoir, means for
controlling said operating means including a monitoring de-
vice comprising a pressure-sensitive hydraulic cell comprising
a chamber having therein a reversible diaphragm separating
the chamber into a head pressure sub-chamber and a trans-
mission sub-chamber which sub-chambers are sealed from one
another by the diaphragm means effecting communication be-
tween the main and the head pressure sub-chamber, a resilient
plastic metering tube in pressure transmitting connection
with said controlling means and of a length and resilience to
substantially absorb and prevent transmission of surge shocks
from said monitoring means device to said controlling means,
and transmission liquid substantially filling said metering
tube and said transmission sub-chamber, and said diaphragm
when low head pressure in the main is monitored by the moni-
toring device and the diaphragm projecting into said head
pressure sub-chamber, said diaphragm being reversible into
said transmission sub-chamber when high head pressure in the
main is monitored in the monitoring device and wherein the
~` _A _
during low head pressure in said main and the diaphragm being reversible
from said head pressure sub-chamber into said other sub-chambcr in response
to main head pressure to :Eorce fluid through the metered communication for
operating said means responsive to said monitoring means.
Other objects, features and advantages of the present invention
will be readily apparent from the ollowing description of certain represent-
ative embodiments thereof, taken in conjunction with the accompanying
drawings, although variations and modifications may be effected without
departing froM the spirit and scope of the novel concepts embodied in the
disclosure, and in which:
Figure 1 is a side elevational view of apparatus embodying features
of the invention;
Figure 2 is a top plan view of the apparatus;
Figure 3 is a fragmental enlarged vertical sectional detail view
taken substantially along the line III-III o~ Figure 2;
Figure 4 is a fragmen~ary vertical sectional detail view taken
substantially along the line IV-IV of Figure 3;
Figure ~ is a vertical sectional elevational detail view taken
substantially along the line V-V of Figure l;
Figure 6 is a fragmentary end elevatlonal view taken substantially
along the line VI-VI of Figure 3;
Figure 7 is an electrical operating circuit diagram; and
Figure 8 is a fragmentary sectional detail view of a main pressure
probe which may be used under certain circumstances.
In a typical apparatus embodying features of the invention and
especially suitable for use in a municipal water system, a small
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Z~7;~6~
compact base 10 will suffice to suppoxt at least most of the
elements of the apparatus. For example, the unit as mounted
on the base 10 may be about 29 lnches long, about 6 inches
wide and about 10 inches high.
A principal feature of the apparatus is a scale beam
12 which is pivotally mounted adjacent to one end and extends
freely in spaced relation over the base 10. Dividlng the beam
12 into a relatively long lever portion 12a and a short tail
portion 12b is a horizontal axle structure 13 (FIG~ 4) pro-
jecting to opposite sides of the beam end portion and journaled
in anti-friction bearings 14 mounted in a frame 15 comprising
spaced upright standards 15a secured in fixed relation on one
end portion of -the base 10. ~ubrication of the bearings 14
is adapted to be effected through a grease gun fitting 17
communicating directly with one of the bearings and with the
other of the bearings through a passage 18 in the axle. A
counterweight 19 (FIGS. 1-3~ is mounted adjustably on a
threaded stem 20 projecting from the distal end of the beam
tail 12b.
According to the present invention, the beam 12 is
calibrated and equipped to assume settinqs for pounds and
feet, having in mind that water column height in a reservoir
can be determined in pounds pressure by multiplying by a
factor of 2.307. With this information in mind, the lever
portion 12a mav, as shown in FIGS. 1 and 3, be provided with
calibration indicia 21 preferably along the front side of
the beam providing a weight (pounds or kilograms) pressure
scale along which a selector weight 22 riding slidably on
the beam is adapted to be adjusted. A gauging face area 23
(FIG. 5) on the weight 22 facing toward the distal or ~ree
end of the beam portion 12a may carry an indicati~g indicia 24
'7~6
adapted to be aligned with any selected one of the calibrations
along the scale 21, by sliding the weight 22 into the selected
position. Thereby, what may be re~erred to as a primary
or general setting i5 aaapted to be effected for the particular
liquid level control desired. Then, -to attai.n a more p~ecise
or fine trimming of the level in the water column, a smaller
weight 25 is adjusted along a scale 27 calibra-ted at height
intervals (feet or meters) of water level and desirably
located along the top surface o~ an auxiliary beam bar 28
which is mounted in longitudinally extending spaced clearance
relation above the weight 22 on the beam 12 as by means of
spacer column studs 29 at its opposite ends which respectively
extend short of the frame 15 at the pro~imal end portion and
the distal end portion o~ the lever portion 12a, thereby
providing a substantial bar length for the height scale 27
along which the weight 25 is adapted to be adjusted by sliding
i~ along the bar 28.
In order to control the plvotal attitude of the beam
12 in operation of the apparatus substantially in agreement
with monitored reservoir liquid level head pressure, means in
the form of an actuator 30 (FIGS~ 3 and 4) are provided at
one end, i.e., the tail end 12b, of the beam functioning in
cooperation wit;h the balance weight means comprising the weight
19 and the weights 22 and 25. For this purpose, the actuator
30 desirably comprises an expansible bellows 31, carried
by the frame 15 in overlying relation to the end portion 12b.
On its upper end the bellows 31 is sealed to a closure disk
32 secured in supported relation on the underside of a
bridging head element 33 at the top o~ the frame 15. On its
lower end the bellows 31 is sealed to a closure disk 34
which carries a coaxially downwardly projecting conically
tipped pi~ot point element 35 engaged in a generally
L27Z~
complementary upwardly opening, frusto-conical pivot bearing
socket 37 in the beam tail portion adjacently spaced rela-tive
to a vertical plane through the axle 13.
Means are provided for rendering the bellows actuator
30 pressure-responsive so that internal pressure wi.thin -the
bellows 31 will cause lt to expand and thereby press the
pivot point 35 against the beam 12 causing the beam to swing
about its pivotal axis in opposition to the bias of the balance
weights 22, 25, and raise the distal end of the beam lever
12a, for example, to the intermediate position shown in FIG.
1 or the full line position substantially fully raised to the
limit position shown in FIG. 3. When the pressure drops in
the bellows the distal end of the beam lever portion 12a
may be permitted to drop to a lower limit position as indicated
in dash outline in FIG. 3. For this purpose, the bellows
31 is maintained substantially filled with a transmission
fluid 38 such as oil and communicates by means of an oil-
filled system including a pressure metering duct 39 (FIG. 1)
leading from a head pressure monitoring cell 40 tapped
as by means of a pipe 41 into communication with a main 42
! which may comprise a standpipe or lead from a standpipe 43
extending from a reservoir 44 whi.ch may be a municipal water
tank or the like. A shutoff valve 45 may be in control of
the pressure conducting pipe 41, and a bleeder valve 45a
may be located adjacent to an end of the pressure cell 40
which preferably comprises a generally cup-shaped portion
47 into which water under pressure from the main 42 is tapped
by the pipe 41. A generally cup-shaped oil chamber portion
48 to which the duct 39 is coupled, is joined to the portion
47, there being a pressure transmitting diaphragm 49
sealingly clamped between the chambers 47 and 48 to separate
;
z~
the water from the oil~ In a preferred form, the cell ele- -
ments 47 and 48 are of the same standardized size. The
flexible diaphragm ~ is of a generally cup shape, with
tapered sides, and has a thickened base 50 normally pro-
jecting toward the closed end of the chamber portion 47
against which it can safely bottom if -the~e is a pressure
surge in the oil-fillecl transmission system. Oil leakage
in the transmission system or pressure surges from the main
42 cause the diaphragm 49 to flex responsively. Should the
oil leakage be severe enough, or it becomes necessary to
open the oil-filled transmission system, the base 50 is
adapted to move toward a seat 51 at the port into a fitting
52 which couples the duct 39 centrally to the closed end of
the chamber 48. The base 50 thus acts as a shut-off valve
pressing sealingly onto the seat 51 as indicated in dash
outline in FIG~ 1. At either extreme of flexure bottoming
of the base 50 avoids overstressing and possible rupture
of the diaphra~m 49.
At the actuator end of the hydraulic transmission
system, the duct 39 is coupled in communication wi-th the
bellows 31 by means of a fit-ting 53 including an elbo~ 54
(FIGS. 1 and 2) at one end of an elongated hollow T-nipple
55 having therein a passage 57 (FIG. 3) which communicates
under the control of an angle needle valve 58 operable by
means of a knob 59 with a passage 60 which extends through
a connec-ting nipple 61 secured to the head member 33. The
nipple 61 projects to a limited extent into the upper end
of the chamber within the bellows 31 in a manner to provide
an air space head room 62 accommodating a pressure relieving
safety cushion, vibration damping, air bubble in the head
of the bellows chamber. Projectin~ upwardly from the
coupling body 55 is a filler and air bleed or purging nozzle
63 communicating with the passage 57 and under the control
oE a shutoff valve having an operating knob 64~
Means are provided at -the dis~al end of the lever l~a
for controlling opera-tion of liquid suppl~ means for the
reservoir 44 in accordance with the pivotal a-ttitude o~ the
beam as controlled by the balance weight n~eans and the monitor-
responsive actuator means 30. To this end, an upper limit
stop is carried in overlying relation to the distal end of
the beam lever 12a by a post 67 rising from the base 10, and
a lower limit stop 68 is carried by the base 10 in underlying
relation to the lever portion 12a. Means comprising a
transverse trip arm bar 69 carried by the distal end portion
of the beam lever 12a underlies switch trip means comprising
one or more, in this instance four, trip lever fingers 70
which operatively overlie the arm 69 and project from re-
spective mercury switch carriers 71 (FIGS. 3 and 6), each
of which is equipped with a rocker coupling 72 pivotally
connected as by means of a pin 72a to an ~pwardly projecting
mounting stud 73 on a respective dielectric mounting block
74 vertically individually adjustably fastened to the base
10 as by means of a pair of machine screws 75 in opposition
to an upward biasing coiled spring 77 thrusting at one
end against the base 10 and at the other end into a blind
end socket 78 opening downwardly in the block 74. In this
manner, the several switch carriers 71 are adapted to be
individually adjusted into optimum vertical position relative
to the trip arm 69, as best visualized in FIG. 6.
Although for a small capacity reservoir a single
supply pump might suffice, a plurality of supply pumps for
each reserYoir is usual. By way of illustration, therefore,
726i~;
the apparatus is shown as equipped to handle -three supply
pumps identiEied as Pl, P2 and P3 in FIG. 7~ It will be
understood, of course, that each of these pumps whether
connected to a single water source or to a plurality of
wells, will be in supply communication with the reservoir
44 in the usual manner. In the carriers 71, a mercury
switch 79 is provided for controlling pump Pl, a n~ercury
switch 80 for the pump P2 and a rnercury switch 81 for
the pump P3, and a holding switch 82~ The arrangement of
the switch carriers as to adjusted angle of inclination
and elevation is such that the switches will be opened
and closed sequentially under the control of the beam
carried trip arm 68 and the trip fingers 70. All of the
mercury switches are connected with a suitable power line
83 through an on-off switch 84 (FIGS. 1, 2 and 7) and re-
spective relays 85, each of which is operatively connected
with a respective one of the pump motors, in circuit with
starters 87 for the motors. A protective fuse 88 is con-
nected in the power line 83, and respective fuses 89 are
connected in the electri.cal lines between the relays 85 and
the pump motors, the fuses being conveniently mounted on
the front of the base 10. A suitable terminal array 90
(FIGS. 1 and 2) is mounted on the base 10 adjacent to the
switch mounts 71 to facilitate electrical connections for
the mercury switches. A suitable electrical terminal array
91 on the adjacent end portion of the base 10 facilitates
electrical connection of the pump motors in the operatin~
control circuit.
Flexibility, adaptability and convenience in oper-
ations of the pumps Pl, P2 and P3 is enhanced by interposing
between the control switches 79, 80 and 81 and the relays
--10--
~ 7~
85, respective selector switches 92, 93 and 94 operable
by means of respective knobs 9~a, 93a and 94a accessible on
the front of the base 10~ Each switch has "o-ff" and "A",
"B" and "C" positions. Any pump may be shu-t down by turniny
its switch knob to the "off" position. Any desired sequence
of operation of the pumps is attained by appropriate adjust-
ment of the associated selector switch 92, 93 or 94 to the
"A", "B" or "C" position, and also desirably adjusting the
height of the associa-ted mercury switch 79, 80 or 81. For
example, an adjustment differential in water column in the
reservoir 44 may be attained varying from 3 inches to 6 feet
at which the respective pumps are automatically energized in
the operation of the apparatus. Therefore, by suitable
adjustment of the selector switches any sequence order of
operation of the pumps may be selected. In the setting shown
in FIGS. 1 and 7, the sequence is for initial operation of
the pump Pl followed by the pump P2 and then the pump P3, but
this may be varied as and if circumstances dictate. If
preferred, of course, any of the pumps may be paired, or all
of the pumps may be set through the selector switches to
operate substantially simultaneously. In any desired setting,
however, the "hold" switch 82 avoids overworking of the lead
pump within a desired minimum top fluctuation range.
In a typical normal operating sequence as controlled
by the apparatus, and after the balance beam 12 has been
adjusted for the maximum water column level desired, and
assuming the reservoir 44 has been fill~d to such maximum
level, the water column pressure moni-tored by the cell 40
causes the actuator 30 to expand and depress the tail por-
tion of the beam 12, thus raising the switch control end ofthe beam so -that the trip arm 69 raises all of the trip
~Z7;~
levers 70 and thus opens all of the switches 79-82 and
places all of the pumps Pl-P2-P3 in idle, standby condition.
Upon dropping of the water level in the reservoir 44 and thus
lowering of the water column the switch control end of the
beam 12 is permitted to driEt downwardly proporkiona-tel~y
until the hold switch 82 is closed so as -to prepare the relays
85 for energization. Further, lowering o~ the water column
accompanied by proportional downward drifting of the control
end of the beam 12 eventually results in closing of the
mercury switch 79, 80 or 81, as the case may be, and in the
illustrated example the switch 79, energizing its relay 85
and thereby the motor for pump Pl, which mav fully replenish
the reservoir, and thus cause the beam 12 to open the switches
79 and 82. If the water demand is such as to cause a progres-
sion in the water column drop even though the pump Pl is
operating, then as the second low level for which the switch
80 has been adjusted is reached, that switch is closed and
the pump P2 is cu-t in. If that does not ta~e care of the
situation, and the water level continues to drop, until a
third low water level stage is reached, the switch 81 closes
due to the continuing downward drift of the control end of
the beam 12, and the pump P3 is cut in. Presumably, the
combined volume of all three pumps will maintain at least
the minimum level in the reservoir 44 under the heaviest
emergency demand placed upon it. As the water demand
diminishes, and the water level rises, the control end of
the lever 12a gradually rises until the maximum water level
has been reached in the reservoir 44 and the holding switch
82 is opened to stop the pumps. Accordingly, when the
control apparatus has been adjusted, rellable, automatic con-
trol of the supply pumps is maintained continuously, responsive
-12-
to the monitored head pressure in the main ~2.
Even in municipalities of modest size, it generally
requires numerous wells to supply the water demand. Accordingly,
a separate appara-tus as described may be provided Eor each of
several clusters of wells to supply a lar~e reservoir or
separa-te reservoirs. In order to avoid overwo~kin~ the pumps
in any given cluster or ield, it is desirable to relax -the
pumps in any given cluster or field over the other clusters
or fields. For this purpose, level drop controlling means
are provided for adjusting the balance beam 12 to attain the
result of relaxing the pumps under its control, without
effecting any changes in the basic adjustments in the apparatus.
For this purpose, a swing weight in the form of a lever 95 is
mounted by means of a pivot 97 on a clevis post 98 fixedly
secured to the end of the "foot" bar 28 as by means of a stud
99 which also secures the bar 28 to the underlying post 29 and
the post to the beam 12. By swinging the lever weight 95 to
its "NORMAL" position where it projects in the direction of
the end of the beam 12, substantially adds the weight of the
lever 95 to the switch controlling end of the beam 12 and
thereby increases its leverage. On the other hand, when the
lever weight 95 is swung back into the "STANDBY" position over
the bar 78, the increased weight leverage on the beam 12 is
relieved. Through this arrangement, substantial differences
in the water level in the reservoir 44 can be attained before
the pumps are set into operation, simply b~ swinging the
lever weight 95 from what may be termed minimum water level
differential where the lever weight is in the extended posi-
tion as shown in full outline in FIG. 1, as compared with the
unextended position as shown in FIGS. 2 and 3. For example~
where a water level differential of only a few inches may be
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'7Z~
desired for normal opera-ting intervals, and during which the
lever weight 95 will be placed in its extended position, it
may be desirable to provide a relaxed, more or less standby
condition in which a water level dif~erential of several feet,
such as 2 or more ~eet, may be tolera~ed. Neverthel~ss, -kh~
pumps will be ready to operate when -the relaxed maximum
differential level drop is reached, and especially, the entire
system will be ready to operate for any emerqency. In
municipalities, this is especially advantageous because the
lowest fire insurance rating can be claimed by virtue of the
continuous availability of maximum water supply to meet any
emergency.
By manipulation of the extendible l~ver weight 95, the
apparatus provides for controlled fall or level drop and rise
in the reservoir water level to accomplish at least two major
purposes, not the least of which is to prevent stagnation so
that at least at controlled intervals a substantial volume
of fresh, chlorinated water will be added to the water volume
in the reservoir. This is especially desirable in hot weather.
Where freezing temperatures are encountered, such level drop
and rise will avoid icing in the reservoir b~ bringing in
sufficient replenishment of warmer, generally ground tempera
ture water to maintain the reservoir water body temperature
above freezing.
According to the present invention, this effect is
also easily accomplished automatically in conjunction with or
in addition to the extendible lever weight 95 by controlled
holding of the balance beam 12 in the off-switch position
for a suitable interval to permit the reservoir water level
to drop a desired distance, for example, 2 to 6 feet, as
preferred, and at any suitable time. For this purpose, a
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selectively operable level drop controlling means device in
the form of a solenoid 100 (FIGS. 1, 2, 3, 5 and 7) is
mounted by means of an upstanding plate 101 -fixed as b~
means oE screws 102 to the inner edge of -the top member 33 o~
the frame 15 and in overlying relation to the beam 12 and
more particularly the adjacent end portion of the bar 28.
Normally, the solenoid 100 is deenergized 50 tha-t its armature
103 depends freely below the solenoid. In this relaxed posi-
tion of the solenoid a yoke bar 104 carried by a pair of
tension springs 105 freely underlies the balance bar 28 so
that the balance beam assembly can function in the normalmanner. When it is desired to effect an anti-stagnation
and/or anti-icing, reservoir level drop, the solenoid 100 is
energiæed to draw the yoke bar 104 firmly against the
underside of the balance bar 28 and thereby hold the balance
beam assembly against drifting downwardly until the desired
water level drop has been attained, whereupon the weight of
the balance beam assembly relieved from the operational
counterbalancing effect of the actuator 30 will overcome the
tension of the springs 105 and drop to activate the pump
system to at least maintain the dropped level and avoid un-
necessary reservoir depletion. When the solenoid 100 is
deenergized, the yoke bar 104 drops and releases the balance
beam for normal operation. An automatic control electrical
circuit for the solenoid 100 includes an on-off control switch
107 desirably located for easy access at the front of the
base 10. Automatic operation of the solenoid 100 at sui-t~ble
selected time intervals such as during daylight and night-
time hours when water demand is expected to be at a minimum
and stagnation or icing ma~ result is desirably effected by
closing the switch 107 and placing control with a timer 108
7~6~
in the electrical circuit for the solenoid and which will
close the solenoid circuit for a suitable interval during
which it may reasonably be expected that the reservoir water
level will drop sufficiently to effect the anti-stagnation
and/or anti-icing function. Connection of the -timer 108 with
the solenoid lO0 and the power line may be through a terminal
array 108a (FIG. 2) on the ~ase lO. A-t the end of the pre~
determined interval, the time clock opens the circuit, de-
energizing the solenoid and releasing the balance beam
assembly for normal operation. To permit adjustments of the
solenoid lO0 for the attainment of controlled reservoir water
level drop to a preferred level within a substantial range,
for example, at any selected level from 2 to 6 feet, depending
upon the relevant conditions, the elevation of the solenoid
may be adjusted as, for example, by the provisions of vertical
adjustment slots lO9 in the plate lOl providin~ vertical
clearance for attachment screws llO by which lateral flanges
lll on the solenoid casing are secured to the mounting plate
101 .
In situations where the main size is small in relation
to pump volume, thus causing an abnormal back pressure, a
probe 112 ~FIG. 8) may be mounted as by means of a stem 113
extending through a packing gland 114 in the main 42' with
the outer end of the stem 113 suitably coupled to the tap
pipe 41. As shown, the probe 112 may comprise a head which
is oriented generally axially in the main so that it can be
turned by rotation of the stem 113 to have its inlet orifice
oriented downstream so that the water pressure obtained by
the probe before the monitoring cell 40 will be the same
whether water is being pumped to the main or there is merely
static water column pressure in the main. In order to permit
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` ~;Z7Z~6
proper adjustment of the probe 112, the stem 113 may be
equipped on its outer portion with a handle 117 which may
also serve as a position indicator pointer with reference to
indicating indicia 118 such as an orientation notch in khe
closure cap portion of the gland 114.
Substantial avoidance of water pressure surges being
transmitted from the cell 40 to the actuator 30 results from
having the metering duct 39 of adequate length and preferably
also at least slightly resilient. Excellent results have
been obtained with a length of about 10 feet (3 meters) of
nylon tubing of about 1/8 inch (4 mm) outside diameter having
about a 1/6 inch (2 mm~ inside diameter.
Means are desirably provided for releasably locking
the balance weights 22 and 25 in adjusted position~ For this
purpose, the balance weight 22 is constructed in two parts
22a and 22b (FIG. 5) receiving the lever portion 12a of the
beam 12 in a reeess 120. The weight portions 22a and 22b are
normally in a slightly spaced relation to one another, with
the recess 120 slightly shallower than the thickness of the
bar 12 so that by means of screws 121 the weight portions can
be drawn into snug engagement with the beam 12 after a
preferred setting has been attained. If desired, the screw
tightened relationship of the weight 22 on the beam may be
fixed until the screws are loosened. However, a preferred
arrangement comprises having tensioning means in ~he form
of coiled compression spxings 122 interposed between the
heads of the screws 121 and the bottoms of suitable recesses
so thatthe tightening will be under spring pressure wherein
the engagement between the gripping fa~es of the weight elements
22a and 22b will be thoroughly frictional to prevent displacement
of the weight 22 from an adjusted position on the beam 12
-17-
7~66
against normal vibrations or brushing against the weight,
but when it is desired deliberately to readjust the weight
that can be done by application of moderate manual force.
Similarly, the balance weighk 25 comprises two parts,
25a and 25b, also in normal slight spaced gap re]ation to o~e
another, and means comprising a screw 123 dri~ing against a
coiled compression biasing spring 124 draws the elements 25a
and 25b into gripping relation on the bar 28 which is received
in complementary recesses 125 in the confronting faces of the
weight elements 25a and 25b. Thereby the weight 25 may also
be either fully tightened on the bar 28, or, as preferred,
firmly frictionally tightened so that it will resist normally
expected displacement pressures or forces but can be deliberately
manually slidably shifted along the bar 28 for readjustment
as desired.
