Note: Descriptions are shown in the official language in which they were submitted.
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RAPID TRANSFER AND MIXING OF TREATMENT FLUID
INTO A LARGE CONFINED FLOW OF WATER
FIELD OF THE INVENTION
lo The rapid transfer and uniform mixing of treatment fluid, ozone, for
example, into
a major flow of water through a large conduit, for example in the treatment of
water in
municipal installations.
BACKGROUND OF THE INVENTION
Treatment of water in municipal and industrial sites generally starts with raw
water from some source from which solids are extracted, and subsequent
treatment with
injected treatment substances. The objective is commonplace- the effluent
water is to be
clarified and purified sufficiently to be acceptable into the water
distribution system.
This is an age-old objective, generally involving filtration separation, and
chemical treatment to eliminate objectionable organisms. As cities and systems
have
grown in size, so has their need to treat water that requires more treatment
and more real
estate for the treatment facilities to occupy.
Large settling ponds that could formerly be accepted are increasingly
unsuitable
for growing systems. The dwell-time and consequences of known treatments were
and
are too costly in processing, in equipment, and in space to put the equipment.
Often a less
desirable system was selected despite its disadvantages because it was the
best available.
Large flows of water in confinement as contemplated by this invention are
large
diameter pipes, usually 8 inches inside diameter or larger flowing full under
pumped
pressure. Larger diameters are contemplated, and smaller ones also fall within
the scope
of this invention. However, the systems of greatest interest are those with
flow rates
between about 2 and 200 million gallons per day.
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These are rapid flows into which this invention injects treatment gas in the
pipe
without interruption of the major flow. With this invention settling ponds,
dwell tanks
and the like become unnecessary or the need for them is greatly reduced. It is
an object
of this invention to provide injection of treatment substances in such a way
that they will
be thoroughly mixed with the flowing stream while in the pipe, without
impeding the
major flow. Treatment substances will generally be fluid, this term includes
liquids and
gases.
Prior art projects, such as shown in United States patent to Mazzei, No.
6,730,214
have suggested injection of treatment gas into the stream, but generally this
was done in
io the main stream, and the total system was divided in two parts that were
later combined.
The loss of energy is apparent, as is the increase in required equipment and
real estate on
which to place it (see its Fig. 1).
The ultimate mixing of the treatment gas into the mainstream depends in large
part on the means by which it is injected into the main stream_ Optimizing and
accelerating this mixing is the principal objective of this invention, and is
sometimes
called "flash mixing". However, ultimate mixing is further improved by
providing
treatment gas already well-distributed in its own supply stream, and delivered
in an
optimum stream to the major flow. This invention fosters this additional
object.
2.0 BRIEF DESCRIPTION OF THE INVENTION
This invention is used in a confined-flow conduit under pressure such as a
pipe.
The system has an upstream end and an effluent end. Between these ends there
is an
unimpeded region of flow. A by-pass conduit extends into this region from
upstream of
it.
The purpose of this by-pass conduit is to by-pass a portion of the total
stream
while receiving one or more from mixer-injectors correct amounts of treatment
gas, and
then branching into at least one pair of injection nozzles that discharge the
additive-laden
fluid into the said region. Treatment gas is given here as an example of a
treatment
substance, either gas or liquids.
According to this invention the member of the pairs of nozzles are directed
into
the main stream in the same plane, preferably a plane that includes the
central axis.
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According to a preferred but optional feature of the invention a plurality of
these pairs,
spaced apart longitudinally from each other are provided.
According to other optional features of this invention, advantage can be taken
of
improvements to mixer-injectors, and injection nozzles described in the
following United States
patents to Mazzei, Nos. 5,863,129 and 5,894,995. With the use of some or all
of these products, the
performances of the major system are further improved.
This system operates with no impediment to free flow through it, and with only
a moderate
loss of energy consumed in the operation of the by-pass conduit. This is an
effective small-footprint
system which requires little or no separate power and little operational
attention.
This writing has disclosed at least the following concepts.
Concept 1. A system to inject treatment substances into a flowing stream of
water contained
in a closed structure having a flow axis, said structure comprising an outer
wall with an axially-
extending lumen with a region where injection occurs, and an upstream end and
a downstream end,
said system comprising: a by-pass conduit passing through said outer wall; an
injector having an inlet
connected to said by-pass conduit, an outlet, and a treatment substance entry
port, said injector
having an internal converging section at said inlet, an internal diverging
section at said outlet, and
between said converging and diverging sections, an injector section also
connected to said treatment
substance entry port; a pair of injector nozzles fitted in and discharging
into said lumen, said nozzles
each having a discharge axis, receiving equal amounts of flow from said
injector, said discharge axes
lying in the said plane that includes said flow axis; a pump impelling water
through said by-pass
conduit; and a source of treatment substance connected to said substance entry
port; whereby with
water flowing through said structure and by-pass water flowing through said by-
pass conduit, the by-
pass water passes through said injector, receiving treatment substance from
said source, flow from
said injector divides to the nozzles of said pair, and is injected into the
flowing water stream in the
lumen in paths which lie in the same axial plane, there to mix into the
flowing stream.
Concept 2. A system according to Concept 1 in which the discharge axes of the
members 5
of each pair are substantially co-linear.
Concept 3. A system according to Concept 1 in which said structure is a pipe,
and the
flowing stream substantially fills said pipe.
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Concept 4. A system according to Concept 1 in which twisting vanes are
provided in the wall
of said converging section, and straightening vanes are provided in the wall
of said 0 diverging
section.
Concept 5. A system according to Concept 1 in which a plurality of said pairs
of nozzles are
provided together with an injector for each pair, all of said injectors being
connected to said by-pass
conduit and to said source.
Concept 6. A system according to Concept 4 in which a plurality of said pairs
of nozzles is
provided, the nozzles of all of said pairs being axially aligned along said
structure, said pairs being
axially spaced from each other.
Concept 7. A system according to Concept 1 in which a degassing device is
provided
between each mixer-injector and the nozzles through which it exists.
The above and other features of this invention will be fully understood from
the following
detailed description and the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a semi-schematic drawing of the preferred embodiment of system
according to this
invention;
Fig. 2 is a cross-section taken at line 2-2 in Fig. 1;
Fig. 3 is an axial cross-section of the presently preferred mixer injector for
use in gas
systems; and
Fig. 4 is an axial cross-section of the presently preferred nozzle for use in
this system.
DETAILED DESCRIPTION OF THE INVENTION
A pipe 10 for carrying a substantial flow of water to be treated has an
upstream intake end 11
and an effluent end 12. Between these ends is a mixing region 13. The
direction of total flow is
shown by arrows 14. These ends and regions are at arbitrary locations with the
pipe. For example,
the ends are not necessarily ends of pipe segments, nor is region 13 well-
defined. These items are
given to designate respective generalized locations in the continued unimpeded
flow through the
pipe.
A by-pass conduit 20 extends through the pipe wall 21 upstream of the region,
and divides
into two branches 22, 23.
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As best shown in Fig. 2, branch 22 flows into the intake 24 of a mixer-
injector 25,
and from its outlet 27 divides into branches 30, 31. Branches 30, 31 discharge
into
respective nozzles 34, 35. Branch 23 includes identical elements, branches 30a
and 31a,
mixer-injector 25a, and nozzles 34a and 35a.
Nozzles 34 and 35 have respective discharge axes 37, 38. Importantly, in the
preferred construction these axis are coaxial and confrontational, directly
across a major
part of the cross-section of the pipe. When the pipe is circular they will
intersect the
center 39 of the lumen of the pipe. Similar relationships exist with nozzles
34 and 35 and
their respective axes.
Coaxial discharge of the nozzles of this pair is preferred but optional.
However,
they should be in the same plane, but may make an angle with each other as the
center of
the pipe.
Treatment gas or other additives is supplied to the mixer injectors from a
supply
40 which discharges to the respective mixer-injectors through pipes 41, 42.
The additive
used in this invention for large-scale operations will usually be ozone, but
instead may be
other treatment gases such as chlorine or oxygen or aqueous solutions of
various types.
The identity of the treatment substance is not a limitation in this invention.
The term
treatment substance is used for all fluid additives, the word fluid including
both gases and
liquids.
. = Two pairs of these nozzles, as shown in Figs. 1 and 2 are preferable,
although
only one and as many as four pairs may be used. When more than one pair is
provided,
nozzles will preferably be axially aligned along the pipe as shown.
It does require some power to remove the by-pass flow, pass it through the
mixer-
injector and return it to the main flow. An auxiliary pump 50 is provided for
this
purpose. Instead other known means to provide a differential passing may be
utilized.
The ultimate objective of this invention is to inject treatment substances
into the
flowing confined system so that it is rapidly thoroughly distributed in the
total flow, and
in a condition that there is little remaining undissolved treatment gas to
lose to the
atmosphere.
Dwell time is of importance for the inactivation of an organism or oxidation
of
contaminates. Generally, increase of time in conventional installations
requires a
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proportional increase in the size of the installation. Reduction of the
reaction time ended
by this invention further enables reduction of plant size.
For this purpose the principal advantage of this invention is derived from the
head-on collision of the opposing streams from opposing members of a pair of
nozzles
into the main stream. Injectors as simple as the one shown in Mazzei US Patent
No.
4,123,800, will serve. However, this older injection design does not fully
address the
fine-division of bubbles of treatment gas injected into the by-pass stream for
purposes of
speeding the reaction.
This function is addressed by the mixer-injector fully shown and described in
io Mazzei .US Patent No. 5,863,128. Fig. 3 will be recognized as Fig. 1 of
this patent. It is
characterized by a body 60 having a circular passage 61 with a converging
section 62, an
injection section 63 and a diverging section 64. Twisting vanes 65 are formed
on the
wall of the converging section, and straightening vanes 66 are formed on the
wall of the
diverging section. Treatment gas from branch 67 is fed into the injection
section. The
structure and function of this mixer-injector will be fully understood from
that patent.
Fig. 4 will be recognized as Fig. 3 of Mazzei Patent No. 5,894,995, which
patent
is referred to herein and incorporated in its entirety for its showing of the
preferred nozzle
for use in this invention. This nozzle includes a body 70 with a central axis
71, an
.20 upstream end 72 and a discharge end 72a. Its internal inside bore 73 is
reduced by a
converging section 74 into which a plurality of twisting vanes 75 is placed_
The result is
to discharge a strong stream of water whose outside boundary is twisted
relative to the
inside "core" of the stream thereby providing a further mixing of the
treatment
substances.
The nozzles of the two pairs of nozzles in Fig. 1 are axially aligned.
Extensive
tests have shown this to be preferable to arrangements in which the nozzles
are not
normal to the axis of the stream. The nozzles should be "pointing" in a plane
that
incorporates the central. Divergence of the nozzle axis from a plane that is
normal to the
central axis is acceptable, within limits. It will be recognized that, while
the discharged
streams will be somewhat deflected by the main flow, depending on the velocity
of the
main flow, initial discharge normally to the axes of flow provides best
results.
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In actual operation, main line flows through the reactive section will usually
be
between about 2 to 10 feet per second, and between about 7 to 25 percent of
the total
flow of the system will be through the by-pass. The hydrodynamics of these
systems is
very arbitrary. The system as described and claimed herein has been developed
with the
s objective of the most complete and uniform mixing of treatment substances
into the total
flow. Experimentation has shown that, especially with use of the mixer-
injector of Fig. 3
and the nozzles of Fig. 4, nearly uniform distribution over the entire cross-
section of the
lumen is attainable, all at low cost. The very fine division of gas bubbles
within a few
seconds in the mixer-injector of Fig. 3 is an especial improvement to this
system all at
o lower cost.
The principal objective of this invention is to speed into a solution a
treatment gas
in an uniform manner. A previous problem, especially when ozone is the
treatment gas,
is that it is obtained from oxygen or from oxygen in the air: Accordingly, the
treatment
- gas when ozone will include oxygen, which can cause significant erosion and
corrosion
is problems. For this reason, treatment system flow included degassing
devices.
Ozone itself readily dissolves, at least in concentrations contemplated by
this
invention is different, and will often remain in bubbly form. There is
attained to by
degassing devices such as shown in United States Patent No. 5,622,545. When
used it is
best practice to remove the gas before it enters the main stream. Accordingly
degassed 80
20 and 81 are shown downstream to each mixer-injector, which may be any
degassing
device shown or described in said Patent No. 6,730,214.
Ibis invention is not to be limited by the embodiments shown in the drawings
and
described in the description, which are given by way of example and not of
limitation,
25 but only in accordance with the scope of the appended claims.
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