Note: Descriptions are shown in the official language in which they were submitted.
~04236~
This is a divisional application of Canadian Patent Application No.
183,664, filed October 19, 1973.
This invention relates to a discharge element, in particular for
liquid gas separator units that are adapted for use with downhole oil well
pumps to separate gas from the liquid to be pumped from the well.
Liquid-gas separator units are used downhole in oil producing wells
to perform the task of separating gas from well liquid before it is pumped out
of the wells. Any significant amount of free gas present in undissolved form
in an oil producing well hinders the pumping of the well liquid, which may
include other liquids in addition to crude oil, out of the well. Various
United States patents, such as 2,104,339 to Arutinoff, 2,311,963 to Pyle,
2,285,169 to Pyle and 3,624,822 to Carle, describe liquid-gas separator units
and provide information as to why such units are used. As evidenced by these
patents, there are different kinds of units that work according to different
physical principles, and their performance characteristics, as might be
expected, depend upon their particular features. There does not appear to be
~.
` any particular unit, of which applicant is aware, that is not limited, in one
; way or another, in its performance capabilities.
A superior separator unit, in general, is one that is capable of
discharging liquid at a high flow rate, after separating free or undissolved
gas from the liquid, to provide relatively gas free liquid. Moreover, a
superior liquid-gas separator unit can function to separate widely varying
quantities of free gas, ranging from negligible gas flow rates constituting
negligible proportions of a liquid flow rate up to large gas flow rates cor-
responding to several times the liquid flow rate~ without any significant
change (i.e., decrease) in the liquid flow rate through the unit and, in
addition, can perform the separation function with essentiallynegligible gas
carry-over in the liquid discharged from the unit. Inherently, a high per-
formance unit is one which efficiently separates gas from liquid and discharges
liquid which has only a relatively small amount of undissolved gas remaining
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1o4;~36l
therein, because significant quantities of free gas in the discharged liquid
may hinder efficient pumping of liquid from a well in which such a unit is
utilized. A truly superi~r unit is capable of effective use in wells wherein
large quantities of undissolved gas are present in the well liquid.
The present invention provides a discharge element, adapted for use
in a separator unit, comprising: a cylindrical body having upper and lower
portions, a vertical bore extending through a central portion of the body, the
lower portion defining a gas collection chamber, at least one passage in the
body communicating with the gas collection chamber and leading upwardly there-
- 10 from to a respective passage port on the exterior of the body, the passage
; port being adapted to discharge a stream of gas in a substantially upward
direction, the gas collection chamber being defined by a circular body lip, at
least one passageway formed in the circular body lip and extending in an up-
wardly curved path from the lower end of the lip to a respective passageway
port communicating with a central region of the upper body portion.
; The nature of the present invention will become apparent upon
- review of the following detailed description taken in conjunction with the
figures of the accompanying drawings, where:-
:~ Figure 1 is a central vertical section of a unique separator unit
. ~ .
with other parts connected to it;
Figure 2 is a side elevation with portions broken away showing a
unique impeller used in the separator unit of Figure l;
Figure 3 is an end view taken in the direction of arrows 3-3 of
Figure 2;
Figure 4 is a side elevation showing fragment of the impeller of
Figure 2;
Figure 5 is an end view taken in the direction of arrows 5-5 of
Figure 4;
Figure 6 is a side elevation of a unique discharQe plug element
used in the unit of Pigure l;
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104Z361
Figure 7 is a plan view, taken in the direction of arrows 7-7 of
Figure 6, of the element shown in Figure 6;
Figure 8 is a central section taken along line 8-8 of Figure 7;
Figure 9 is a bottom view of the element shown in Figure 6; and
Figure 10 is a central section taken along line 10-10 of Figure 9.
The separator unit 10 illustrated in Eigure 1 is comprised of a
vertically disposed tubular casing 12 forming a cylindrical chamber 12a where-
in a rotatable impeller 16 is disposed. Impeller 16 has a tubular hub 18 with
a longitudinal bore 19 and a plurality of long, thin, narrow vanes 20. Hub
1~ includes an upper counterbore wherein a corrugated ring sleeve 24 is press
fitted between it and an impeller shaft 26, and further includes a lower
counterbore containing a corrugated ring sleeve 28 press fitted between hub 18
and shaft 26. Sleeves 24 and 28 coact to affix impeller 16 to shaft 26.
,,
A discharge plug element 30 is threaded into the internally
threaded upper end of casing 12, and an intake plug element 32 is threaded
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into the internally threaded lower end of casing 12. Intake plug element 32
includes six intake openings or ports 32a that are uniformly circumferentially
spaced about plug 32. Each port 32a slants upwardly (e.g~, at an angle of
about 60 with respect to a horizontal plane) toward the casing axis and is
radially oriented. Intake element 32 further includes a relatively wide
diameter tubular upper portion 32b with external threads for use in joining it
to the lower end of casing 12, a relatively narrow diameter tubular lower
portion 32c, and an intermediate tapered portion 32d wherein intake ports 32a
are located. The body of element 32 defines an interior chamber 32e that
communicates with the lowermost portion of casing chamber 12a.
Intake plug element 32 may be provided with a plurality of vanes
that extend inwardly from the interior wall of the element's body toward the
center of the chamber. Por example, six vanes 32f, indicated by phantom lines
in Figure 1, may be added to element 32, and these vanes could be axially
oriented, also as indicated in Pigure 1. These vanes could be located in
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1~4;~361
equispaced relation about the interior body wall between the six intake ports
32a, and could be appropriately configured (i.e., straight, vertically elon-
gated or helically curved) to interact with liquid-gas mixtures flowing thro-
ugh ports 32a toward impeller 16. Such vanes, if provided, cauld be used to
alter and/or control the flow of liquid-gas mixtures upward through the
chamber defined by the body of intake element 32 whereby a liquid-gas mixture
flowing past them would impinge on the lower ends of the impeller vanes in
such fashion as to set up an efficient mixture flow pattern.
The externally threaded lower end of a liquid conductor casing 34
is threaded into the internally threaded upper end of discharge element 30.
The upper end of conductor casing 34 is fastened to the lower end of a pump
casing 36 (constituting part of a pump stage, not shown) by screws 38 in the
~- manner indicated in Figure 1. The lower end of intake plug element 32 is
screw fastened to the upper end of a motor casing 40 by screws 41 in the manner
indicated in Figure 1. The pump casing 36 confines c~nventional pump impellers
(not shown) that are affixed to a pu~p shaft 42 having a lower end, which is
shown in Figure 1, that is axially coupled to impeller shaft 26. Shafts 42
and 26 are coupled together, so that they will rotate together, by a key pin
44 within aligned key slots in shafts 42 and 26 and a corresponding keyseat in
a coupling sleeve 46. A coupling pin (not shown) fits within a transverse
hole in shaft 42 and diametrically opposed transverse holes in sleeve 46, to
secure the sleeve to the shaft.
Discharge plug element 30 has a central, vertical bore containing
a sleeve bushing 48 affixed therein to provide a journal for a portion of
shaft 26 that passes through the bushing. Intake plug element 32 has a bore,
coaxial with the discharge plug element's bore, with tubular bushing 50 that
provides a journal for a corresponding portion of a shaft coupling 52. Shaft
coupling 52 is connected to shaft 26 by a key pin 54 disposed within a keyway
of shaft 26 and a keyseat of shaft 52. A retainer pin 56, securely fitted
into a transverse bore in shaft coupling 52, protrudes radially into the lower
end of the corresponding connecting shaft key slot to prevent the key pin 54
-- 4 --
104Z361
from falling out of the coupling 52. A coupling pin (not shown) fits within
a transverse hole in impeller shaft 26 and diametrically opposed transverse
` holes in coupling 52 to affix the coupling to the shaft. Two diametrically
opposed openings 32g are provided in element 32 to allow for the insertion of
the pin into the holes of coupling 52 and shaft 26. The upper end of an
- electric motor shaft 58 is fitted into the lower end of shaft coupling 52 and
secured thereto by a key pin 59 seated within a key slot of coupling 52 and a
keyseat of shaft 58. A set screw 60 screw threaded into a transverse hole in
`~ coupling 52, extends into a radial opening in shaft 58 to fasten the coupling
~ 10 and shaft together.
h~ The lower end of the separator casing 12 includes three vertically
, spaced circular rows of inlet/recirculation openings or ports that surround
the lower end of impeller 16 in the illustrated unit 10. The topmost row
; comprises twenty-four openings 62 that are uniformly spaced about the casing.
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i The lowermost row likewise comprises twenty-four openings 64 that also are
- uniformly spaced about the casing, with each openlng 64 located axially below
a respective opening 62. The intermediate row, i.e., between the aforesaid
~ows, similarly comprises twenty-four openings 66 that are uniformly spaced
about the casing and staggered in relation to openings 62 and 64. Each open-
ing 62, 64 and 66 is radially oriented and slants upward toward the casing's
~ . .,
; central axis.
- Five impeller vanes 20 ~Figures 2-5) are spaced uniformly at 72
intervals around the impeller hub 18, and these vanes extend lengthwise along
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the hub approximately its entire length. These vanes comprise straight,
axially oriented strip segments 20a extending from the upper end of the hub
down to spiral shaped strip segments 20b that extend to the hub's lower end.
The vane segments 20a and 20b of each vane 20 merge in the lower half of the
vane. The vanes have outermost edges 20c each located the same distance from
the hub's axis. Each vane segment 20b curves spirally downward in a clock-
- 30 wise direction ~as viewed from above) to terminate in a lowermost vane edge
- ; - 5 -
104Z36~
20d that is disposed within a radial plane A (Figure 2) taken perpendicular
to the impeller's vertical axis W. Each straight vane segment 20a is disposed
within an axial plane B (Figure 3) taken through the impeller's vertical axis.
Thus it is understood that the planes A and B are normal to each other. As
seen in Figure 3, each vane edge 20d is also disposed in an axial plane C
(Figure 3) located 90 clockwise from the axial plane B wherein the segment 20a
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of the same vane is disposed.
In~operation, impeller 16 is caused to revolve in a clockwise
direction i.e.J in the direction indicated by the arrow D in Figure 1. The
~ 10 impeller vanes 20 act to develop a high pressure head in the chamber 12a below
-. discharge element 30. Since each vane segment 20b spirals 90 downward from
. an axially oriented vane segment 20a to an axially oriented edge 20d the slope
" angle X ~see Figure 4) at the vane's inner edge 20e is greater than the slope
angle Y at the vane's outer edge 20d. In the example, the angle Y (see Figure
4) is about 12 while the angle X is about 30.
The discharge plug element 30, illustrated in Figures 6-10J is
comprised of a generally cylindrical body 70, including an upstanding tubular
lip 72 forming a liquid receiving chamber 72a at its upper end that conducts
liquid coming from passages 100 upward into the liquid conductor casing 34.
Lip 72 has internal threads 76 (Figure 8) used to scæ~w together element 30
and conductor casing 34 in the manner shown in Figure 1. Body 70 has outer
threads 78 used to screw element 30 into the upper end of separator casing 12
as shown in Figure 1. Body 70 includes a tapered flange-like body portion 80
forming an annular shoulder 80a that seats upon the upper end of casing 12
when element 30 is assembled with the casing. Body 70 has a central hub por-
tion 82 forming a bore 84J concentric with the central vertical axis of body
70, that receives bushing 48 and impeller shaft 26 in the manner indicated in
Figure 1. Hub 82 merges with a tubular lip 86 forming a cylindrical gas
collection chamber 86a.
As seen best in Figures 9 and 10, body 70 has four internal gas
104Z361
channels or passages 96 symmetrically arranged about the body axis and leading
-`~ upward from inlets 96b at the lower body chamber 86a to four respective pas-
sage outlets 96a spaced 90 apart on tapered body portion 80. Body 70 also
has four symmetrically arranged exterior liquid channels, passageways, or slots
100 each of which spirals upward in a clockwise direction ~as viewed from the
~; upper end of element 30) from an inlet lOOb at the lower end of element 30 to
i a respective outlet aooa communicating with upper body chamber 72a. The four
outlets lOOa are located at 90 intervals ~see Figure 7) with each outlet lOOa
offset 45 from adjacent interior ports 96a.
The configuration of body 70, the network of gas conveying passages
96 and liquid conveying passageways 100, and the proximity of body 70 to
impeller 16 cooperate to facilitate the flow of liquid from impeller 16 to
passageways 100 with minimum loss in the hydrokinetic energy of the liquid.
Since body 70 lies immediately above impeller 16 and is vertically spaced there-from by only a small vertical gap, the liquid flowing from the upper end of
impeller 16 approaches inlets lOOb with essentially the same 1OW velocity
that it has as it spirals upwardly from the impeller. The body portion defin-
~- ing ports or inlets 96b of passages 96 is located above the ports or inlets
lOOb of passageways 100 and does not pose an obstacle to the flow of liquid
into the passageways 100. The passages 96 and passageways 100 are arranged so
that liquid can flow in an unobstructed path away from impeller 16 into the
passageway inlets lOOb without having to flow past a body portion containing
pass?ges 96. This arrangement is advantageous because the obstruction-free
liquid flow path allows for substantial conservation of liquid hydrokinetic
energy as liquid flows toward passageways 100.
In the illustrated embodiment of the invention all the passageways
or channels 100 are identical. Each channel 100 tsee Figure 6) is defined by
two slot~walls 104 and 106 extending from the channel inlet lOOb to the channel
-I outlet lOOa. Each channel 100 includes a lowermost upwardly sloping portion
of small slope angle Z (20 with respect to a horizontal plane in the illus-
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~ ~04~:361
trated embodiment) merging with an uppermost, upwardly sloping channel por-
tion whose slope angle varies and approaches 90 at the channel outlets lOOa.
The slope angle Z is such that liquid energy loss sustained in the liquid
flowing from the impeller 16 into channels 100 is minimized. The width of at
least a segment of the lowermost portion of each channel 100 increases with
~ increasing distance from lower end 30a of element 30. The changir.g width of
- the channel segments provides an increase in channel area in the direction
~- of liquid flow therethrough. Thus, in the illustrated embodiment, each channel
100 has straight wall portions 104a, 106a, extending between points Pl, P2 and
P3, P4 respectively, that diverge in the channel direction toward the
associated uppermost channel portion which is of constant width. The lower-
most channel portions are therefore widest at points Pl and P3 where the upper-
; most channel portions begin. In the illustrated discharge plug element 30,
the wall portions 104aJ 106a of each channel 100 diverge at an angle of 5
from a centerline L of the channel. Thus, the angular divergence between wall
portions 104aJ 106a is 10.
Separator unit 10 operates as follows. As motor shaft 58 revolves
at a constant rate impeller shaft 26 and impeller 16 likewise revolveJ where-
upon impeller 16 draws a liquid-gas mixture through intake openings 32aJ into
the chamber 12a. As this liquid-gas mixture moves upwardly within chamber 12a,
the revolving impeller vanes 20 impart a compound motion to it. Impeller
vane segments 20b impel the mixture primarily upward through chamber 12a, while
vane segments 20a primarily impart circular motion to the upwardly moving
mixture, thereby centrifuging the liquid component of the mixture outwardly
away from impeller hub 18 and causing undissolved gas present in the liquid
to move inwardly toward hub 18. The separated liquid flows up through dis-
charge channels 100 into discharge element chamber 72a. The separated gas
foDms a liquid-free gas column around hub 18, which column of gas moves upward-
ly into discharge element chamber 86a from whence the gas flows into inlets
96b and through gas conducting channels 96 to stream from gas discharge out-
-- 8
~)4'~36~
lets 96a in nearly vertical, upward directions. The channel outlets 96a dis-
charge discrete high velocity gas streams of separated gas that are substan-
tially upwardly directed to promote upward movement of the discharged gas
within a well bore (not shown) wherein unit 10 is situated.
The liquid entering the inlets lOOb of channels 100 possesses both
hydrostatic and hydrokinetic energy. The liquid flowing upwardly through
channels 100 flows at a velocity that diminishes as the liquid flows along the
tapered channel portions defined by wall portions 104a, 106a between points
Pl, P2, P3 and P4. The path of channels 100 is such that the liquid velocity
is diminished within the channel segments extending between wall portions 104a,
106a before the liquid flows to and through the uppermost channel portions.
The flow path promotes liquid flow through channel 100 with minimal liquid
energy loss. As liquid flows through the tapered channel portion (between
i points Pl, P2, P3 and P4 in the illustrated embodiment) of each channel 100,
a portion of the liquid hydrokinetic energyJ which is proportional to the
square of the liquid velocity, is converted into hydrostatic energy, thereby
raising the hydrostatic pressure of the liquid delivered to the lower end of
the pump casing 36. The lowermost portions of channels 100 are oriented at a
slope angle Z (Figure 6) to allow flow of upwardly spiralling liquid into
channel inlets lOOb without any substantial change occurring in the direction
or velocity of liquid flow from the uppermost end of impeller 16.
The mixture inlet openings 32a of intake plug element 32 slope
upward at an angle of about 60 (with respect to a horizontal plane) so that
the liquid-gas mixture flows through them toward impeller 16 with little change
in flow direction. The approximately vertical orientation of openings 32a,
and the substantial intake area provided by them, facilitates transfer of a
large quantity of mixture through the unit in a relatively short amount of
time.
- The inlet/recirculation openings 62, 64, 66 significantly increase
the mixture flow rate through unit 10. During operation of unit 10 a hydro-
104~361
dynamic condition is established wherein liquid-gas mixture flows into chamber
12a through some of the openings 62, 64, 66 and flows out from chamber 12a
through others; resulting in a net flow of liquid into chamber 12a. It should
; be understood, however, that the inlet--recirculation openings 62, 64, 66 are
not essential to the operation of unit 10 and can be eliminated but they are
provided because they extend the unit's liquid throughput capacity and reduce
gas carry-over with the discharged liquid. The lowermost openings 64 increase
liquid throughput capacity at low gas rates (i.e., a liquid-gas mixture with
a relatively small proportion of component gas), and the openings 62~ 56 in-
crease liquid throughput capacity at higher gas rates ~i.e., a liquid-gas
mixture with a relatively high proportion of component gas).
The described unit 10 possesses several advantageous performance
characteristics. Liquid is discharged from unit 10 with a substantial pres-
sure head due to the coaction of impeller 16 with the liquid conveying channels
; 100 of discharge element 30.
At the discharge element 30 the separated liquid enters liquid
conveying channels 100 that act as diffuser passages wherein liquid velocity
head is recovered, and wherein the liquid flow is turned in an upward axial
direction prior to discharge from outlets lOOa. Pressure recovery in dis-
charge element channels 100 reduces the volume of any carry-over gas entrained
with separated liquid ~hile providing a supercharging effect at inlet 36a ~see
Figure 1) of pump casing 36. This supercharging improves the pumping action
i.e,, raises the volumetric efficiency of the pump) and pressuri~es the
liquid at inlet 36a so as to reduce the likelihood that dissolved gas within
the liquid will come out of solution and produce undesirable cavitation in the
pump, which cavitation could impair the pump's action or cause physical damage
to it. In channels 100 the reduction of liquid velocity is accomplished in
the channel segments between portions 104a, 106a before any change in direc-
tion of this liquid stream occurs, reducing the friction loss associated with
such changes in direction.
, - 10 -
~04Z3S~
The ports or outlets 96a of gas conveying channels 96 are orientcd
to discharge upwardly directed discrete gas jets whereby, as is desirable,
the likelihood of recirculation of the discharged gas to the intake openings
32a of intake element 32 is minimized. These gas jets assist in the upward
expulsion of the discharge gas through the annular space between unit 10 and
the well casing (not shown) to the top of the well where free gas escapes into
a collection apparatus capping the upper end of the well bore. In this way,
inefficient repetitive recirculation of discharged gas through unit 10 is
minimized. Moreover, these gas jets create a minimal amount of turbulence in
-~ 10 the well liquid outside unit 10 near gas discharge outlets 96a so that the ten-
dency of discharged gas to become re-entrained with well liquid upon leaving
outlets 96a is restricted. The increased annular area provided about dis-
charge element body portion 80 between casing 34 and the surrounding well cas-
ing (not shown) permits any carry-over liquid that might flow through passages
96 from chamber 86a to separate out o a supporting gas discharge ~et and flow
downward between the jets of gas issuing from passage outlets 96a toward in-
take element 32 without re-entraining gas. The unit 10 acts like a centri-
~ugal pump in that the rate of discharge of liquid decreases with accompanying
increases in hydrostatic pressure head and vice versa. The unit 10 will
operate with a negative head (i.e., discharge pressure less than suction
pressure).
` ~ The liquid-gas mixture enters chamber 12a due to the pumping action
-~ of impeller vane portions 20b, and the straight vane portions 20a whirl the
mixture at high velocity. Impeller 16 accomplishes liquid-gas separation so
; effectively that there is little gas carry-over with liquid even at high gas
flow rates and low liquid discharge pressures, presumably because the depth of
liquid near the wall of casing 12 is sufficient to completely fill the liquid-
conveying channels 100 or because inward flow from channels 100 to chamber 72a
via ports or outlets lOOa tends to exclude gas from entering this chamber.
Gas is discharged through gas discharge outlets 96a due to the hydrostatic
1042361
pressure head provided by energy imparted by impeller 16 to the separated gas
and/or by the pressure gradient which exists between intake element 32 and
discharge element 30.
The unit 10, by providing a hydrostatic pressure head at liquid
reservoir chamber 86a, reduces the tendency for cavitation to occur in the
pump operatively connected to unit 10. Also, since liquid velocity head is
recovered in the channel segment defined by wall portions 104a, 106a of channels
100 the liquid pressure increases whereby the liquid discharged from such
channel segments is at a pressure such that the liquid is not saturated with
gas. It therefore is less likely that dissolved gas will be released from the
liquid at points of reduced pressure downstream of the location defined by
points Pl-P3 of discharge element channels 100.
~~ With no undissolved gas present in the liquid entering chamber 12a
via intake element 32, liquid is discharged through gas-conveying passages 96.
~- Whenever any aoount of gas, however small, is present in the liquid entering
chamber 12a a stable gas core, it is theorized, is formed with the impeller
driven liquid forming a liquid ring or annulus around the core. The depth of
this ring is self regulating, and is such that all the liquid is at a greater
radius than the inlets 96b to the gas conveying passages 96. Consequently, as
; 20 is rather amazing, with any small amount of gas present in the liquid entering
chamber 12a via intake element 32 essentially no liquid discharges from gas
discharge outlets 96a under an extremely wide range of liquid or gas flow
rates. This characteristic is highly desirable since any liquid that does
` carry-over into and through pass?ges 96 recirculates down the outside of casing
12 toward intake element 32 and may, in doing so, re-entrain discharged gas
~` in the process.
Preliminary laboratory tests of unit 10 have been conducted and,
although lab tests can not fully duplicate actual use conditions, they in-
dicated (1) that unit 10 effects a degree of liquid^gas separation that great-
ly exceeds the separation capability of existing units, (2) that unit 10 can,
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~042;~61
under test conditions, efficiently separate the liquid and gas components of a
liquid-gas mixture and discharge large quantities of free gas and relatively
gas free liquid at substantial flow rates, and (3) that unit 10 can, under
test conditions, effect substantial separation of gas from a liquid-gas mixture
that contains a high proportion of undissolved gas. The test results in-
dicated that unit 10 possesses performance characteristics that surpass those
of existing units.
During the tests the unit 10 and an existing unit were tested using
the same test apparatus~ The test data showed the way in which liquid flow
rate through each unit varied with positive or negative pressure head. It was
found that the pressure head or discharge pressure ~measured in feet) generated
by unit 10 greatly exceeded, by a large factor, the pressure head generated by
the existing unit over a wide range of liquid flow rates (measured in gallons
of liquId per minute). The discharge pressure is the pressure head generated
by a unit. When gas free liquid was supplied to each unit it was found that
the liquid flow rate through unit 10 greatly exceeded, by a large multiple
factor, that of the existing unit for the same pressure head level. It was
. found that at zero discharge pressure the liquid flow rate through the existing
~ .1
unit was only about 17 gallons per minute while that through the unit 10 was
about 82 gallons per minute. It was found that when the positive pressure
; head of the existing unit was equal to about 7 feet the liquid flow rate was
-~ zero gallons per minute. By comparison, when the positive pressure head of the
unit 10 was equal to about 40 feet the liquid flow rate was about 30 gallons
per minute.
Startling results were observed when comparative tests were carried
out to determine the discharge pressure versus liquid flow rate curves of unit
10 and the existing unit when liquid-gas mixtures containing varying propor-
tions of gas therein were supplied to the intake openings of the units. When
as little as 0.55 cubic feet per minute of gas was introduced into the liquid
going into the intake openings of the existing unit it was found that the
- 13 -
~042361
unit's liquid flow rate reduced to zero gallons per minute. By comparison, it
was found that when 26 cubic feet per minute of gas was introduced into the
liquid going into the intake openings 32a of unit 10 the liquid discharge
rate exceeded 70 gallons per minute at zero feet of discharge pressure. More-
over, it was found that the discharge pressure versus liquid flow rate curve
of unit 10 shifted only small amounts with increasesin the amount of gas intro-
duced into the liquid supplied to intake openings 32a up to large gas flows.
More particularly, the liquid flow rate at a given pressure head decreased in
small amounts with increases in the quantity of gas, measured in cubic feet
per minute, entrained with the liquid going into unit 10. These measurements
taken during the tests clearly indicate the vast superiority bf the unit 10
over the other unit that was tested.
The laboratory tests were conducted using air as the gas and water
as the liquid, together with a surfactant to reduce surface tension of the
water. The existing unit and the unit 10 effect separation of gas and liquid
by using different principles. The unit 10 relies upon an impeller to achieve
liquid gas separation, whereas the existing unit primarily relies upon a
series of conventional separator cups to achieve liquid-gas separation. The
..,
existing unit is a duplicate of some units that have been used in recent years
in numerous oil wells to separate out hydrocarbon and other gases from crude
petroleum prior to pumping the petroleum ~and any other liquids that may have
~- been introduced into the subterranean formation containing a well tofacilitate
the petroleum recovery process). The existing unit is also typical of vir-
tually all the units used in recent years in this application in that they
~ employ such separator cups. Since these units have been extensively used in
- oil producing wells it is believed that the laboratory tests have substantial
validity in demonstrating the usefulness of the liquid-gas separation unit 10
for oil well applications. Although unit 10 is intended for use in oil well
applications the tests clearly demonstrated that it can be used as a liquid-
gas separator in other applications wherein liquid and gas other than petrol-
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1042~
eum and hydrocarbon gases are to be separated for a useful purpose.
Presumably the unit could be used to separate immiscible liquids
of different densities.
The unit could be used as a pump or with pumps driven either by a
line shaft or a submersible motor.
:~,
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