Note: Descriptions are shown in the official language in which they were submitted.
5~
The present invention relates to a fluid injection ;:
system for injecting a first fluid into a body of
a second fluid.
In accordance with one aspect of the present invention
S there is provided a fluid injection system comprising
a tubular member arranged to form part of a fluid line
through which, in use, fluid flows under pressure, a
venturi contained within the tubular member, means
defining first and second volumes arranged to contain
: 10 first and second fluids respectively, said first and
second volumes being separated by a~pressure respons1ve
means, the tubular member on a high pressure side of the
: : : venturi being in fluid communication by means of
: a conduit with said means defining said first volume,
and a line extending from~the tubular member on a
low pressure side of the venturi and being in
~ : fluid communication with said means defining said
: second volume, the arrangement being such that, in
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use a pressure differential is created across
the venturi so that the firs~ volume is increased
by.fluid passing from the fluid line into the first
volume and by movement of the pressure responsive
means, the second volume is correspondingly decreased
by fluid passing therefrom through the conduit into
: 25 the fluid fIowing through the fluid line, wherein
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1~90151
bypass conduit means is provided between the high
pressure side of the venturi and the line on the low
pressure side of the venturi so as to provide an alternate
flow of fluid in the line and modify through volumetric
S displacement the rate of flow of the second fluid.
In accordance with another aspect of the present
invention there is provided a method of injecting a
first fluid with a second fluid, which comprises forming
a first volume containing the first fluid and a second
volume containing the second fluid and separating the
volumes by pressure responsive means, passing a stream
of fluid through a venturi so as to create a pressure
differential in the stream, causing the pressure
differential to act on the pressure responsive means to
15: increase the ~irst volume and to decrease correspond-
ingly the sec~nd volume and to displace second fluid
: rom the second volume and inject the:displaced second
fluid via a line into the stream of fluid, wherein the
.
: ~ rate of injection of the displaced second fluid into
the stream of fluid is modified by an aLternate and
displacing flow of fluid from the stream set up in the
line.
The present invention will now be described, by way
o~ example, with reference to the accompanying drawings,
in which:-
! Figure 1 is a schematic view o~ a first embodiment
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of a fluid injection system of the present invention;
Figure 2 is a schematic view of a second embodiment
of a fluid injection system of the present invention;
Figure 3 is a schematic view of an application of the
embodiment of Figure l;
Figure 4 is a sectional view through an isolating
valve of the apparatus of Figure 3;
Figure 5 is a sectional exploded view through a
shuttle valve of the apparatus of Figures 1 and 3,
Figure 6 is a plan view of an apparatus embodying the
scheme of Figure l;
Figure 7 is a sectional view taken along the line 7-7
of Figure 6;
Figure 8 is a side elevation of an apparatus embodying
the scheme of Figure 2;
: 15 Figure 9 is a view of a bottle neck sealing arrangement
of the apparatus of Fiqure 8;
Figure 10 is an upper perspective view of a part of the
apparatus of Figure 9;
Figure 11 is a perspective view of a knap sack wand
ln accordance with the present in~ention;
Figure 12 is a perspective view of an adaptor of the
wand of Figure 10; and
Figure 13 is a side elevation of part of the.adaptor
of Figure 11 showing the spring mounting of a tube
member.
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In Figure 1 of the accompanying drawings there is shown
a fluid line lO through which, in use, a fluid flows
under pressure. Co~pled within the fluld line 10 is a
tubular member 12. Each end of the fluid line 10 is
connected to the adjacent end of the tubular member 12
by an convenient means.
The tubular ~ember 12 contains a venturi 14 arranged
to cause a pressure drop in fluid flowing through the
fluid line 10 in the direction shown by the arrow 16.
The tubular member 12 also contains two orifices 18
and 20 on the high and low pressure sides of the venturi
14 respectively.
A first conduit 22 extends from the orifice 18 to~a
pressure tank 24. The pressure tank 24 is of rigid
construction.
The pressure tank 24 is bucket shaped having a base
26 with an upstanding peripheral wall 28. The conduit
22 enters the pressure tank 24 through its base 26.
Further, the pressure tank 24 also contains a bladder
or diaphragm or membrane 30 which is of similar shape
to the pressure tank 24 and is thus also bucket shaped.
Typically, the bladder 30 has an upper peripheral flange
remote ~rom its base. This flange is clamped between
an upper outwardly flared end of the peripheral wall 28
of the pressure tank 24 and a lid 32 by any suitable
means such as threaded bolts. The bladder 30 has
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a resilient wall. The bladder 30 may be formed of
neoprene or rubber or any flexible material not degraded
by the fluids. A first volume is defined by the
pressure tank 24 and the bladder 30 and a second volume
is defined by the bladder 30 and the lid 32.
A shuttle valve 34 is mounted above the lid 32.
The shuttle valve 34 communicates with the interior of
the pressure tank 24 through a short pipe 36 which passes
through the lid 32. Further, the shuttle valve 34 is in
communication with a reservoir 37 through a pipe 38 which
passes through the underside of the reservoir 37. The
reservoir 37 is provided with a breather 39. A meterlng
line 40 also extends from the shuttle valve 34.
In use, the shuttle valve 34 performs such that when no
: 15 bulk fluid is passing through the fluid line lO fluid
passes under gravity from the reservoir 37 through the
pipes 38 and 36 to fill up the bladder 30. This causes
the bladder 30 to expand and to move outwardly towards
the base 26 and wall 28 of the tank 24. Thus, the
second volume is increased and the first volume is
correspondingly decreased until the bladder 30 is full.
When fluid flows through the fluid line lO and the
tubular member 12, a pressure differential is created
across the venturi 14. This closes off the supply from
the tank 24 and causes fluid from the fluid line lO to
pass through the orifice 18 and the conduit 22 into
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~.Z90151
the pressure tank 24 and exert pressure on the wall of
the bladder 30. The bladder 30 moves inwardly causing
the second volume t~ contract as the first volume is
increased. Fluid in the bladder 30 is thus expelled
through the line 40~ The fluid passing through the line
40 enters the tubular member 12 via the orifice 20 and is
injected into the stream of the fluid line 10.
It is found over a wide range of flow rates in the fluid
line 10 that the rate of injection varies approximately
according to the rate of flow. Thus, the amount of
second fluid injected per volume of first fluid remains
substantially constant. Preferably, the minimum flow
rate in the fluid line 10 is sufficient to generate a
driving pressure differential that will displace the
~ ~ second fluid. If desired, the tank 24 can be connected
;~ 15 in reverse whereby the bladder 30 is in fluid communic-
ation with the conduit 22 and the tank 24 is in fluid
communication wlth the conduit 40. In this case, the
bladder 30 expands to expell the second fluid from the
tank 24. Furthermore, the separator, instead of being
in the form of a flexible member, could be in the form
of a piston or other member that moves displacing
the ~irst and second fluids.
The rate of injection of the second fluid into the
first fluid may be varied by means of a by-pass conduit
50 which interconnects the conduit 22 with the line 40.
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The presence of the conduit 50 causes the first, bulk
fluid to flow from the conduit 22 into the line 40 as an
alternative to the flow of the second fluid. This
inhibits or proportionately displaces the flow of the
S second, additive fluid into the venturi.
The by-pass conduit 50 contains an adjustable valve 52.
The valve 52 controls the rate of flow of the first,
bulk fluid in the conduit 50. As the valve 52 is opened
to lncrease the rate of flow of the first fluid, the
rate of flow of the second fluid through the line 40 is
decreased and vice versa.
Once the desired rate of addition of the second fluid
has been~established, this rate of addition will be
maintained and the second fluid will flow into the;
15 ~ venturi 14 partly p~e-mixed with the bulk fluid and
will be admixed with the main body of bulk~fluid in
the desired proportion. The valve 52 may be substituted
by a fixed constriction~calibràted to a desired rate.
The constrlction~may be a plug partially restricting
20 ~ the by-pàss ~flow. It may a~lso be a multiposition plug~
for~multiple, pre-set ~rates of flow.~
The system may be extended further to incorporate
adjustment to the venturi or constriction the
purpose of which is to modify the pressure differential
~for a given flow rate) and thereby change the range
;~ over which the second~fluid line and by-pass control
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~Z901~1
the rate of closing. The means of adjusting the venturicould be by mechanical adjustment of a flexible surfaced
opening, by sphincter action, or by pumping additional
volume of the first fluid into the eye of the venturi.
s This latter has been found to control the venturi
constriction.
The apparatus of Figure l has a wide variety of uses.
It may, for example, be used for adding aromatic
materials in small volumes as a catalyst to hydrocarbon
fuels of low quality to increase thethermal output rating.
The apparatus of the present invention provides a safe
method of handling high~ flammable bulk fluids.
The apparatus of Figure l may also be used for metering
liquid additives into bulk fluids in gaseous form such
as the adding of lubricating oil to compressed air
flowing to energise pneumatic tools that require
constant lubrication such as pneumatic hammers on
drilling machinery.
The system shown in Figures l and 2 of the drawings is
arranged for operation with fluids in the form of
liquids but the present invention can be readily adapted
for operation with gases. The system can be extended
to have multiple second fluid lines and storage volumes
and by-pass controllers feeding a single venturi or
multiple venturis in series or parallel.
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In Figure 2 of the accompanying drawings there is shown
an apparatus which is a modification of the apparatus of
Figure 1. Like reference numera s are used to denote
like parts between Figures 1 and 2.
The major difference from the apparatus of Figure 1 is
that the reservoir 37, the pipes 36 and 38 and the
shuttle valve 40 are omitted. Further, the metering
line 40 leads directly from the bladder 30 through
the lid 32 of the tank 24 to the orifice 20.
The apparatus of Figure 2 operates in essentially the same
manner as that of Figure 1 as described above.
The apparatus of Figure 2 is envisaged to be a disposable
system whereby once all of the second, additive fluid
has been expelled-from the bladder 30 the entire
apparatus will be discarded and replaced by a fresh
apparatus ln which the bladder 30 is filled with the
second additive fluid. The apparatus of Figure 2 may
be used in the same applications as that of Figure 1.
However, because of its disposable characteristics
it is useful in other applications. For example, the
apparatus of Figure 2 is particularly envisaged for
use wlth knap sack sprays which are typically used for
spraying herbicides or pesticides. With the apparatus
of Figures 2, the active ingredient to be sprayed would
be contained in concentrated form in the bladder 30 and
the bulk fluid would be water carried in a portable
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90~L5~
tank. The bladder 30 could be so designed that the
operator need never contact the concentrated active
ingredient. Further, the bladder 30 could be incorporated
in a cheap disposable assembly including the entire
apparatus of Figure 2 which would be discarded when the
bladder 30 was empty.
In Figure 3 there is shown a variation of the apparatus
shown in Figure 1, for supplying a solution to a stand
pipe outlet at a height of, for example, about 3 or 4
metres.
The apparatus shown in Figure 3 comprises a mains
supply waterline 60 which feeds through a main on-off
valve 62 to a tubular member 64 which contains a ventur
in similar manner to the tubular member 1~ of Figure 1.
lS The mains supply~line 60 thencontinues on horizontally~
for a distance and then turns through 90 for a distance ~ -
of about 3 or 4 metres to terminate in a stand pipe outlet
66.
The apparatus of Figure 3 further comprises a reservoir
68 of concentrate which is typically at a height less
than that of the standpipe 66. The apparatus of Figure
3 further comprises a dosing tank 70 which is similar
to the tank 24 of Figure 1. The dosing tank 70 is
arranged to be fed with fresh concentrate via a gravity
~ed line 72 from the tank 68. The line 72 comprises
a shuttle valve 74 similar to the shuttle valve 34 of
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Figure 1.
A line 76 leads from the upper end of the tank 70 via
the shu~tle valve 74 to the upper end of an isolating
valve 78 to be described in detail hereinafter. The line
76 then proceeds to a low pressure side of the tubular
member 64.
Further, a conduit 80 leads from a high pressure side
of the.tubular member 64 to the lower end of the isolating
valve 78 and then to the lower end of the tank 70. Still
further, a metering line 82 branches from the line 80
through a control valve 84 and joins with the,line 76. The
valve 84 performs the same function as the valve 52 of the
apparatus of Figure l.
Further, the isolating valve 78 is moved between
,
operating and non-operating positions by means of a
diaphragm actuator 86. The diaphragm actuator 86 is
; connected on one side to the mains line 60 upstream of
: the valve 62 by means of a line 88 and to the conduit
: 80 by means of a line 90.
The'isolating valve 78 also comprises a drain member
92 at atmospheric pressure.
The ap~paratus of Figure 3 operates in similar manner
to that of Figure 1 in that water is fed along the
mains line 60 and thus mains pressure is applied along
the line 80 to the tank 70.. This causes concentrate
to be expelled ~rom the tank 70 along the line 76
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to the low pressure side of the tubular member 64. The
rate of flow of concentrate may be varied by opening or
closing the control valve 84.
Further, the tank 70 can be replenished with concentrate
from the reservoir 68 under the influence of gravity
through the shuttle valve74. However, if it is decided
to cease supplying liquid to the outlet 66 and the valve
62 isclosed then the downstream portion of the line 60
from thevalve 62 is filled with water which has a
substantial head. Thus, through the line 80 a substantial
pressure is still exerted on the tank 70 which prevents
replenishment of the concentrate in the tank 70.
This problem may be overcome by the isolating valve 78,
an embodiment of which is shown in Flgure 4. The~
valve 78 in Figure 4 includes a valve body 100 comprising
a longitudinally extending cylindrically shaped recess
102. There is also a first port 104 arranged to be
connected to the line 76 from the tank ~70, a second port
106 arranged to be connected to the line 76 leading to
the tubular member 64, a third port 108 is arranqed to
be connected to the line 80 leading to the tank 70 and
a ~ou~th port }10 arranged to be connected to the line
80 leading ~rom the tubular member 64. The recess 102
contains a lon~itudinally slidable valve spool 112
arranged to be operatively connected to the diaphragm
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actuator 86. The spool 112 has a first intermediate
cylindrical projection 114 and a second endmost cylindrical
projectior. 116. -
The upper end of the recess 102 as seen in Figure 4
is blind and a coil spring is located between the blind
end of the recess 102 and the spool 112.
Normally, the spring 102 urges the spool 112 downwardly
to the position shown in ~igure 4. In this position
the concentrate can flow through the ports 104 and 106
along the line 76. Further, water can flow through
the ports 110 and 108 along the line 80 to the tank 70. :
The projection 116 seals off the ports 104, 106 from the
ports 108, 110 whilst the projection 114 seaIs of~ the
ports 108, 110 from the drain member 92.
~:~15 However, if the valve 62 is closed there is a higher
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there is from the elevated outlet 66. Thus, there is a
pressuredifferenti~between the lines 88 and 90 which
causes the diaphragm actuator 86 to li.ft and raise
: 20~: the valve~spool 112. In the raised position the valve
spool 112 blocks the ports 104 and 106 by means of the
cylindrical projection 116 and cuts off the port 110
from the port 108 by means of the cylindrical projection
114. In this position the tank 70 is isolated ~rom
the pressure in the line 60 and the water in the line
80 between the isolating valve 78 and the tank 70
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drains away through the port 108 and the drain member
92. This releases pressure on the bladder in the tank
70 and allows the shuttle in the valve 74 to fall so
allowing concentrate to flow along the line 72 under the
S influence of gravity to refill the bladder.
A shuttle valve which has been found to be useful in
the present invention i5 shown in Figure 5. The
shuttle valve of Figure ; includes an upper part 120
and a lower part 122 which are arranged to be threadedly
engaged with one another. The upper part 120 comprises
an internal duct 124 comprising an intermediate tapered
portion 126 provided with an "O"~ring seal 128. The
lower part 122 comprises a duct 130 with a narrow upper
part 132. Further, the lower part 122 includes adjacent
15 ltS upper end an L-shaped port 134.
The valve shown in Figure 5 further comprises a
shuttle 136 which comprises a tapered upper portion 138.
The tapered upper~portion contains an internal; ~a~ ring
seal 140. The port 134 is connected to the line 40 in ~ ~ -
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Flgure 1 or the line 76 in Figure 3. When pressure is
applied to the bladder in the tank, fluid pressure i5
applied through the port 132 so that the fluid from the
bladder can be fed to the tubular member containing
the venturi. This causes the shuttle ~136 to rise until
the tapered portions 126 and 138 are engaged with one
another and a seal is established by the seal 128. This
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prevents any fresh concentrate from being fed from the
reservoir thereof. Howe~ler, when the fluid pressure on
the bladder is stoppedr the shuttle 136 falls under the
influence of gravity until it rests on a shoulder 142
adjacent the port 134. In this position the port 134
is sealed by the sealed off 140 and fresh concentrate
can flow under the influence of gravity through the
ports 124 and 130 into the bladder.
In Figures 6 and 7 there is shown a particular embodiment
of an apparatus constructed in accordance with the scheme
of Figure 3 except that the apparatus contains no
isolating valve 78~ Like reference numerals denote like
parts. In this connection thP tubular member 64 is
rigidly connected to the tube 70 by a plurality of flat
bars 150.
Purther, the lines 76, 80 and 82 are connected to the
tubular member 64 by means of T-pieces 152. The
apparatus shown in Figures 6 and 7 is useful as a stand-
pipe insert for enabling water flowing to the standpipe
to be dosed at a desired concentration.
In Figure 8, there is shown a particular embodiment
of an apparatus constructed in accordance with Figure 2.
Like reference numerals denote like parts.
In Figure 8 the tank 24 is in the form of a clear
plastics bottle and the bladder 30 is in the form of
a plastics bag or the like. The bottle is sealed off
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at the neck by a moulded plastics cap 160. The cap
160 is permanently sealed to the bottle 24.
The cap 160 comprises a male end 162 for f-tting to a
hand wand (not shown) and a female end 164 for fitting
S to a hose or knap sack of known type (not shown). An
apertured tube 166 depends from the cap 160. The tube
166 ensures that the bag 30 is unfurled in the bottle 24
and also acts as a feed tube in use.
The cap 160 also comprises an on-of~ cock 168.
The cock 168 must be on and water must be flowing through
the cap 160 from the female end to the male end to cause
chemicals to be released from the bag 30. The cap 160
also comprises a chemical filler port 170 through which
chemical is inserted into the bag 30. After the bag 30
is full the port 170 is permanently sealed. The cap
160 contains all of the components 12, 14, 18, 20, 22,
40, 50 and 52 of Figure 2.
Thus, when water flows from a hose or knap sack through
the cap 160 from the end 164 to the end 162, the
concentrate in the bag 30 is expelled into the water at
a desired, consistant concentration as determined by
the setting of the valve 52. In this embodiment the
valve 52 may be permanently set at a particular desired
setting. It is also envisaged that in some applications
the valve 52 could have, say two positions which could
be obtained by a manual switchinq deviFe.
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A particular neck construction for the apparatus of
Figure 8 is shown in Figure 9. In this case the bag 30
is sealed to thetube 166 by means of an"O"ringl79.
Further, a neck plug 182 with the tube 166 extending
through it, rests on the neck 180 and closes it off
and is sealed to the bottle 24.
A sealing collar 186 is then clamped around the neck 189
and the assembly. The open end of the bag 30 is sealed
to the filled tube 166 by means of the"O"ring 179 or
other seal so that once the filler port 170 is sealed the
concentrate cannot escape except by rupture of the bottle
24. In this connection, the bottle 24 may be made of
impact resistant plastlcs material. Also, the clear
nature of the bottle enables a visual observation to
be made of the amount of chemical remaining in the bag
30. Also, shown in Figure 9 is the dosing Line 40, the
by-pass 50 or the valve 52 which can be seen more clearly
in Figure 10. The by-pass line 50 and the valve 52
serve to displace the cencentrate thereby changing the
dose rate from the line 40. The control valve 52 may
be replaced by specific plugs that restrict the flow in
the by-pass line 50 to a desired rate of control.
In Figure ll, there is shown a knap sack spray head
190 fitted with an adapter 192 which is shown to an
enlarged scale in Figure 12. The spray head 190
comprises a wand 194 into which the adapter 192 is
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fitted.
The adapter 192 comprises a first internally threaded
end tube 196 and a second externally threaded end tube
198. The tubes 196 and 198 arearranged to be fitted
i to outer and inner ends of the knap sack wand 194
respectively. The tubes 196 and 198 are rigidly
interconnected by a bridgi.~ member 200 such that under
thebridging member 200 there is a gap between the tubes
196 and 198.
Further, as can be seen in Figure 13, the tube 198 is
spring biased by a coil spring 202 to a rest position.
The cap 160 of the apparatus of Figure 9 can be engaged
with the tubes I96 and 198 by pressing the tube 198
against the spring 20 to widen the gap between the
tubes 196 and 198 and then inserting the cap 160 into
the gap. Then the tube 198 can be released so that the
tube 198 sealingly engages with the female fitting 164 and
the tube 196 sealingl~ engages with the male fitting
162. In this way, the bottle 24 of Figure 8 can be
readily cllpped into a knap sack wand~or a hose line
and used until the concentrate is exhausted at which
time the bottle 24 is removed by the reverse of the
procedure described above and replaced by a fresh
bottle.
Modifications and variations such as would be apparent
to a skilled addressee are deemed within the scope of
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the present invention. For example, in the embodiment
of Figure 9, with a spring and orifice part, the plug
170 may be used as a "dead-mans-hand`. That is, unless
the plug 170 is depressed, the plug 170 rises to cut
off the flow in the concen rate flow tube 166.
Further, venturi could be in the form of an invert venturi
in which a solid member is disposed in the centre of a
pipe or tube to form a constriction.
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