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Патент USA US3072068

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Jan. 8, 1963
B. e. CHRISTOPHER ETAL
3,072,053
PIPE LINE CONTROL SYSTEM
Filed Aug. 18, 1961
32
33
PNEUMATIC
CONT ROL
SIGNAL
‘1
PNEUMATIC
CONTROL
52
33a
SIGNAL
TOR
54
I9
AMPLIFIER
53
MASTER
CONTROLLER
United States Patent 0
1
2
3,072,058
Benjamin G. Christopher, Daiias, and George J. Dorris,
_
_
Patented Jan. 8, 1963
PIPE LINE CONTROL SYSTEM
Jr., Midland, Tun, assignors to Socony Mobil Oil Com
pany, Inc, a corporation of New York
Filed Aug. 18, 1961, Ser. No. 132,458
The present invention therefore provides a system in
which the station operating characteristics are initially de
termined by the power demand point or level, which point
is subject to variations under control of existing pressures
at the input and output sides of the pumping station.
Thus, there is provided an e?icient, economic operation of
the pumping station while avoiding the possibility of
physical injury to the station components: and to the pipe
The present invention relates to control systems for
line.
pipe lines and more particularly to a system for con-‘ 10
For other objects and advantages of the present inven
trolling the operation of a pipe line pump station and has
tion, reference may be had to the following detailed de
for an object the efficient operation of a pipe line pump
scription taken in conjunction with the accompanying
station.
drawing in which:
A typical pipe line pump station today includes one
FIG. 1 schematically illustrates the control system of
or more centrifugal pumps employed for boosting pipe
the present invention.
llne pressures along the length of the line. These pumps
Referring now to FIG. 1, there is illustrated a control
are usually driven by electric motors which may or may
system 10 embodying the present invention and shown
1 7 Claims. (£1. 103-42)
not be directly coupled to the pumps.
In more recent
transmit mechanical motion from the motor to the pump
connected to control a pipe line pump station including a
pump 11. The pump 11 is eltective to increase the pres
sure of ?uids ?owing in the pipe line 12 by way of con
and the transmission, or coupling, employed to control
the operation of the pump to maintain the suction pres
which connect an input or suction side of the pump 11 to
developments, a variable coupling has been employed to
nections including the pipe 13, valve 14, and pipe 15
sure and the discharge pressure within predetermined
the pipe line 12. An output or discharge side of the pump
limits. The above pressures are important to pump sta
11 is connected by Way of pipe 16, valve 17, and pipe 18
tion operation, for too low a station suction pressure will 25 to the pipe line 12. A check valve 19 is provided in the
pipe line 12 between the suction and discharge ends of the
cause damage to the pump and too high a discharge
pressure may cause the rupture of the pipe line. There
pump 11 in a manner following usage well known in the
art. While the invention will ‘be described in conjunction
fore, the maintenance of these pressures within pre
with the control of pump 11, it will be understood that
determined limits has been the criterion of operating pipe
tained within the predetermined limits, the station is
additional pumps may be connected in series further to
boost the pressure of the ?uid in the line 12. Such addi
considered to be operating properly.
tional pumps are represented by the pump 29 connected in
line pump stations.
So long as the pressures are main
the pipe line 12 in a manner similar to that abovejde
. However, in recent times another problem has entered
scribed in conjunction with pump 11.
into the operation of pipe line pump stations and that
The pump 11 is driven by an electric motor 21 mechani
has been the economic feature. The cost of power to 35
operate the pump station, that is, the electrical power,
1s predicated upon two cost rates. One cost rate applies
to the actual use of power and the second cost rate, a
demand rate, is a ?xed rate charge independent of actual
cally coupled to the pump by way of a variable coupling
22. The motor 21, usually of a substantially constant
speed, induction type, derives its power by way of con~
ductors 23 and 24 from a power line including conductors
_
total power used. Once a demand rate is established 40 L1 and L2 by way of wattmeter 31.
As thus far described, the pump 11 is effective to regu
for a station the most economic operation of the station
late the discharge pressure and the suction pressure by
will be at a level that does not‘ exceed the power con
sumption level determined by the demand rate. ‘It can be
readily appreciated that operation at a power consump
tion level below that which established the demand rate
variation in the magnitude of coupling between the motor
and the pump. The variable coupling is preferred as ‘a
control means over. a throttling valve for control of pres
sure since the latter predicates its operation upon a loss
of energy within the valve itself to reduce pressure and
thus amounts to less e?icient operation of the power sta
results in higher payment for power actually used. On
the other hand, should the consumption increase to
establish a higher demand rate, the customer will be
_
‘penalized by charges at an increased rate for'power 50 tion from a power consumption standpoint.
In accordance with the present invention, the degree of
consumed.
'
coupling between the motor 21 and the pump 11 is pri
In accordance with a preferred embodiment of the
marily controlled ‘in response to the power consumption
present invention, there is provided a control system for
level of the station. More particularly, the degree of
a pipe line pumping station having at least one pump
coupling is primarily controlled so as to maintain the
driven by an electric motor by way ‘of a variable mechan~
ical coupling. ‘ The control system includes a ?rst control
power consumed at a demand point. As previously set
signal generator which responds to suction pressure on
an input side of a pump for generating a ?rst control
point and to this end a controller 30 responsive to a
forth, such operation is desirable from an economic stand
power-sensing means 31 controls the degree of coupling
signal.‘ A second control signal generator responds to
the pressure on a discharge side of the pump for modify 60 between the motor 21 and the pump 11 so as to maintain
the power consumed by the station at the demand point.
ing the ?rst control signal in accordance with the mag
Further, in accordance with the present invention, this
nitude of the discharge pressure to generate a second
primary function of control provided by controller 30 is
control signal. ‘Control means responds to variations
overridden by control signal generators 32 and 33 respon
about a set point representative of a desired power con~
sive respectively to the suction pressure on an input side
sumption level or power demand level on the station 65
of the pump 11 and to the discharge pressure on an output
for varying the degree of coupling between the motor and
the pump to maintain the station power load at the power
fdemand level. A means responsive to the second con
side of the pump 11 to shift the point about which the
controller operates and thus is effective to lower the power
demand point of the station whenever the suction or dis
trol signal varies the set point in accordance with devia‘
charge pressures exceed predetermined limits.
tions in the discharge and suction pressures from 70
It will be recalled that the controller 30 is responsive to
predetermined magnitudes to avoid damage to the station
and to the pipe line.
the power load on the station and effective to control the
couplingbetween the motor 21 and the pump 11 to main
n)
tain the station power consumption at the demand point.
To this end, the power-sensing means 31 may take the
form of a wattmeter shown connected to the power lines
L1 and L2 and having an output representative of the
power consumed at the station applied by way of con
doctors 34 and 35 to an input of the controller 3%. The
controller 3t) responds to the input signal from the watt~
it
tects a variation pressure beyond the prescribed limits, the
pressure, or supply line pressure in line 54, will be de
creased; thus to lower the demand point for a period until
the pressures have returned to the prescribed limits.
More particularly, the first control signal generator 32
generates a ?rst control signal which under normal op
erating conditions, that is, with the suction pressure at the
input of the pump 11 at or above a predetermined value, is
equal to that of the input supply pressure. A decrease in
tion as determined by the setting of a control knob 36. 10 the suction pressure at the input of the pump 11 will
cause the signal generator 32 to decrease its output pres
The output of the controller 3t? is then active to vary the
sure below the pressure of the input air. The predeter
degree of coupling of the coupling device 22 to maintain
mined level of suction pressure at which the signal gen
the station at the demand point. More speci?cally, the
erator 32 will begin to decrease the pressure of the air
controller 3% may be of the pneumatic type responsive to
transmitted
to the second signal generator 33 may be set
an electrical input signal to vary a pneumatic signal ap
into
?rst signal generator by way of control knob 32a.
plied by way of tubing 4% to a mechanical ampli?er 41.
The second signal generator 33 has a similar control
The mechanical ampli?er 41 has an output lever 42 con
knob
33a which determines the upper limit of pressure
nected by way of mechanical linkage represented by the
for the discharge side of the pump 11. So long ‘as the
dotted lines 43 to a control of the variable coupling 22.
Thus, there is provided, as well known in the art of con .20 discharge pressure is at or below the predetermined level
set into the signal generator, the signal generator will
trollers, a feedback loop eiiective to control the power
transmit to the tubing 5'4, without modi?cation, the out
consumed by the station. Supply air is provided to con
put air from the signal generator 32. Should the dis
troller 30 from a source of constant pressure, for example,
charge pressure exceed the predetermined level, the signal
15 pounds, and applied to the controller by ‘way of con
meter 31 to control the power consumption about a set
point which represents the power demand point of the sta
duit or tubing 37.
Now, no matter what the character of the fluid being
25 generator will now modify the air applied from the ?rst
signal generator, lowering it to a new value which will
in turn lower the set point on the master controller 39
to cause a reduction in coupling between the motor 21
or high viscosity, the power consumption of the station
and the pump 1.1 until the discharge pressure has been
will be regulated primarily so as to maintain operations
reduced
to the preset value.
30
about the selected demand point.
While the signal generator 33 has been illustrated hav
The primary control will be modi?ed in accordance
ing its detector connected to the discharge side of pump
with the present invention to avoid damage to the pump
ll, it will be understood that the detector may be con
station equipment upon deviation of selected parameters
nected at the discharge side of the pump 20. When
beyond predetermined limits. For example, should the
referring to the detection of the discharge pressure at the
downstream pressure increase, thereby to increase the
output side of the pump, the phrase is meant to include
suction pressure at the input side of the pump ll, there
any point which lies to the discharge side of the pump
is a danger that the discharge pressure of the pump will
being controlled, and this may include a point at the dis
reach an amplitude su?icient to rupture the pipe line 12.
charge end of the pump station.
On the other hand, should the downstream pressure de
While the invention has been disclosed in conjunction
crease below normal levels, the suction pressure on the
with a ?uid-type coupling between the motor 21 and the
pump 11 would fall below a safe value and may cause
pump 1.1 in. order to control the discharge and suction
damage to the pump 11.
pressures, it will ‘be understood that the gate valve 17
To avoid damage to the pipe line and station equipment
may be replaced by a throttling valve and that the setting
and to assure operation within safe limits of suction and
discharge pressure, there are provided the control signal 45 of the throttling valve may be varied in response to the
output from the mechanical ampli?er 41 to change the
generators 32 and 33 which are effective upon deviations
discharge pressure on the output side of the pump.
of the aforementioned pressures from predetermined safe
The signal generating units 32 and 33 may be pneu
limits to vary the set point of the controller 3% as deter
matic controllers which are well known in the art. For
mined by positioning of the knob 36 to lower the set point
and, thus, the demand point and thereby reduce the cou 50 example, in one embodiment of the invention now in
operation, the signal generators were of the type available
pling between the motor 21 and the pump ill. This has
from the Mason-Neilan Company of Norwood, Mas
the effect of slowing down the pump to permit the suction
sachusetts, and identi?ed as Model 62115, described in
pressure to rise to or above a safe limit or to cause the
the Catalog No. 268, dated February 1960.
discharge pressure to fall to or below a safe limit. The
The master controller 3%} on the other hand may in the
?rst control signal generator 32 has applied thereto from 55
preferred embodiment take the form of the Minneapolis
a source of supply air, which may be the same supply air
Honeywell Regulator Company’s Pneumatic Controller
as for controller 39, a predetermined level of input air as
with Variable Indexet Type 152, Air-O-Line Pneumatic
by way of conduit 55}. In the preferred embodiment, this
Control System.
predetermined level of input air is set at a value such that
The mechanical ampli?er 41 may be of the type avail
if unmodi?ed by the signal generators 32 and 33 it will 60
able from the Bailey Meter Company and identi?ed as a
maintain the set point established in the controller 39.
Bailey Control Drive, Type AC44.
The control signal generator 32 includes a pressure-sensing
The variable coupling 22 may be of any one of several
device (not shown) connected to the pipe line 12 by way
well-known types. In the embodiment now in the ?eld,
of tubing 51. The output from the generator 32 is con
nected by way of tubing 52 to an input of the generator 65 there is employed a variable coupling available from
American Standard Company and known as the Gyrol
33 whose pressure-sensing element (not shown) is con
Fluid Drive. In such units, the degree of coupling is
nected by way of conduit 53 to the pipe line at a discharge
controlled by the mechanical positioning of a scoop tube.
side of the pump 11;. The output signal from the gen
The scoop tube is located in the recirculating path of the
erator 33 is applied by way of conduit 54> to the input of
70 liquid within the coupling unit. The scoop tube, or
the controller 30.
'eturn path, is provided with a larger capacity than the
Both the control signal generators 32 and 33 are de
input capacity to the unit. Therefore, by raising or lower
signed such that if the pressures sensed by their respective
ing the scoop tube within the unit, there is controlled the
sensing units are within the prescribed limits the supply
amount of liquid within the unit and hence the degree
air will be transmitted to the pipe, or tubing, 54 without
shipped through the pipe line, that is, whether it be of low
modi?cation. However, if either of the sensing units de
of coupling provided by the unit.
-
3,072,058
5
6
More particularly, the position of the scoop tube deter
side, an electric motor, a variable coupling interconnect
ing said pump and said motor, a ?rst control signal
mines the amount of ?uid between the driving and the
driven elements to control the output speed of the cou
pling unit. As the scoop tube is moved toward the outer
periphery of the rotating elements, the ?uid volume be
comes smaller within the coupling unit and therefore its
output speed is reduced, causing a reduction in the speed
of the centrifugal pump to which it is attached.
generator responsive to suction pressure on said input
side for generating a ?rst control signal, a second control
signal generator responsive to the pressure on said dis
charge side for modifying said ?rst control signal in
accordance with the magnitude of the discharge pressure
to generate a second control signal, means for measuring
electrical power to said station for producing a signal
described, other modi?cations and embodiments will be~ 10 representative of the power load of said station, means
come apparent to those skilled in the art; and it is in
for establishing a set point representative of the desired
tended to cover such embodiments and modi?cations as
power demand point on the station, control means re
Now that one embodiment of the invention has been
fall within the scope of the appended claims.
sponsive to variations about said set point of said signal
What is claimed is:
representative of the power load of said station for vary
l. A pumping station including at least one pump hav 15 ing the degree of coupling between said motor and said
ing associated therewith an input side and a discharge
pump to operate said station at the demand point, and
side, an electric motor, a variable mechanical coupling
means responsive to said second signal to vary the set
interconnecting said motor and said pump, a ?rst control
point in accordance with deviations in said discharge and
signal generator responsive to suction pressure on said
suction pressures from predetermined magnitudes.
input side for generating a ?rst control signal, a second 20
5. A pumping station including at least one pump hav
control signal generator responsive to the pressure on
ing associated therewith an input side and a discharge
said discharge side for modifying said ?rst control signal
side, an electric motor, a variable mechanical coupling
in accordance with the magnitude of the discharge pres
interconnecting said motor and said pump, a ?rst control
sure to generate a second control signal, control means
signal generator responsive to suction pressure on said
responsive to variations about a set point representative 25 input side, a second control signal generator responsive
of a desired power demand point on said station for
to discharge pressure on said discharge side, said ?rst
varying the degree of coupling between said motor and
and said second control signal generators being intercon
said pump to operate said station at the demand point,
nected to generate a control signal representative of the
and means responsive to said second control signal to
condition of said pressures on said suction side and on
vary the set point in accordance with deviations in said 30 said discharge side, control means responsive to variations
discharge and suction pressures from predetermined
about a set point representative of a desired power de
magnitudes.
mand point on said station for varying the degree of
2. A pumping station including at least one pump
coupling between said motor and said pump to operate
having associated therewith an input side and a discharge
said station at the demand point, and means responsive
side, an electric motor, a variable mechanical coupling 35 to said control signal to vary the set point in accordance
interconnecting said motor and said pump, a ?rst control
with deviations in said discharge and suction pressures
signal generator responsive to suction pressure on said
from predetermined magnitudes.
input side for generating a ?rst pneumatic control signal,
6. A pumping station as in claim 5 in which one of
a second control signal generator responsive to the pres'—
said generators produces a control signal which is modi
sure on said discharge side for modifying said ?rst con
?ed by the other of said generators in accordance with
trol signal in accordance with the magnitude of the dis
deviations from a predetermined magnitude of pressure
charge pressure to generate a second pneumatic control
to which said other of said generators responds to produce
signal, control means responsive to variations about a
said control signal to which said last-named means re
sponds.
set point representative of the desired power demand
point on said station for varying the degree of coupling
between said motor and said pump to operate said station
at the demand point, and means responsive to said second
control signal to vary the set point in accordance with
deviations in said discharge and suction pressures from
predetermined magnitudes.
7. A pumping station including at least one pump hav
ing associated therewith an input side and a discharge
side, an electric motor, a variable mechanical coupling
interconnecting said motor and said pump, a ?rst control.
signal generator having an input side and an output side
50 and responsive to suction pressure on said input side
3. A pumping station including at least one pump hav
associated with said pump for generating a ?rst control
ing associated therewith an input side and a discharge
signal, a second control signal generator having an input
side, an electric motor, a variable mechanical coupling
side and an output side and responsive to pressure on
interconnecting said motor and said pump, a ?rst control
said discharge side associated with said pump to generate
signal generator having an input and responsive to suc 55 a second control signal, means interconnecting the output
tion pressure on said input side for generating a ?rst
side of said ?rst signal generator with the input side of
pneumatic control signal, means for applying air of con
said second signal generator for modi?cation of said ?rst
stant pressure to said input of said ?rst signal generator,
control signal by said second control signal generator
a second control signal generator having an input, means
in accordance with deviation of said discharge pressure
for applying said ?rst pneumatic control signal to said 60 from a predetermined magnitude, control means respon
input of said second control signal generator, said second
sive to variations about a set point representative of the
control signal generator being responsive to the pressure
desired demand point on said station for varying the de
on said discharge side for modifying said ?rst control
gree of coupling between said motor and said pump to
signal in accordance with the magnitude of the discharge
operate said station at the demand point, and means
pressure to generate a second pneumatic control signal, 65 responsive to said second control signal to vary the set
control means responsive to variations about a set point
representative of the desired power demand point on said
station for varying the degree of coupling between said
motor and said pump to operate said station at the demand
point, and means responsive to said second signal to lower 70
the set point in accordance with an increase in said dis
charge pressure or a decrease in said suction pressure from
predetermined magnitudes.
4. A pumping station including at least one pump hav
ing associated therewith an input side and an output 75
point in accordance with deviations in said discharge and
said suction pressures from predetermined magnitudes.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,977,737
1,997,476
2,539,430
3,007,414
Ne-edham _____________ __ Oct. 23,
Wallene _______________ __ Apr. 9,
Jepson _______________ __ Jan. 30,
Long _________________ _._ Nov. 7,
1934
1935
1951
1961
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