U.S. patent number 3,581,469 [Application Number 04/760,408] was granted by the patent office on 1971-06-01 for conditioner for gaseous sample.
This patent grant is currently assigned to Scientific Industries, Inc.. Invention is credited to Robert Davis, Theodore Shlisky.
United States Patent |
3,581,469 |
Davis , et al. |
June 1, 1971 |
CONDITIONER FOR GASEOUS SAMPLE
Abstract
A conditioner for removing particulate and liquid impurities
from a gaseous sample comprising a number of stages in sequence;
there is an initial stage, optional with the designer, which
consists of a means for cooling the gaseous sample before it passes
to the conditioner; the first stage of the conditioner is a
cyclone, which is an enclosed chamber against the interior wall of
which the sample makes first contact; the particulate impurities
spiral down the chamber wall and eventually settle in a liquid
filled trap at the lower end of the cyclone; a manometer is formed
by the liquid in the trap and the open lower end of the cyclone,
where the liquid is drawn into the lower end of the cyclone by the
reduced pressure within the cyclone due to sample being drawn out
of the cyclone; as its next stage, the conditioner has an
electrostatic precipitator through which the treated gaseous sample
passes; the high electric potential ionizes the remaining
particulate impurities and causes same to cling to an electrode of
the precipitatior, and also vaporizes the liquid impurities; the
precipitator has a novel high potential central electrode
comprising a hollow, closed shell into which incoming sample is
delivered and out of which the sample moves only through narrow
slots; the next stage is a pump for pumping the gaseous sample
through the conditioner; the next stage is a flow dividing chamber
which enables only part of the conditioned sample to flow to an
apparatus requiring it.
Inventors: |
Davis; Robert (Bayside, NY),
Shlisky; Theodore (Far Rockaway, NY) |
Assignee: |
Scientific Industries, Inc.
(Hempstead, NY)
|
Family
ID: |
25059020 |
Appl.
No.: |
04/760,408 |
Filed: |
September 18, 1968 |
Current U.S.
Class: |
96/52; 96/57;
55/315; 55/410; 55/418; 55/439; 55/447; 73/31.07; 73/863.12 |
Current CPC
Class: |
G01N
1/4077 (20130101) |
Current International
Class: |
G01N
1/28 (20060101); B03c 003/01 () |
Field of
Search: |
;55/126,128,134,135,150,154,269,270,315,410,418,439,447
;73/23,28,421,421.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
536,029 |
|
Jan 1957 |
|
CA |
|
1,050,120 |
|
Aug 1953 |
|
FR |
|
Primary Examiner: Talbert, Jr.; Dennis E.
Claims
We claim:
1. In an electrostatic precipitator for removing impurities from a
flowing gaseous sample, comprising
a precipitator chamber defined by and surrounded by a wall
comprised of electrically conductive material connected to a low
electric potential and serving as the low potential electrode of
said precipitator;
a high potential electrode within said precipitator chamber, spaced
away from and insulated from said precipitator chamber wall and
connected to a high electric potential;
said precipitator having an inlet; said precipitator having an
outlet communicating with said precipitator chamber;
the improvement comprising said high potential electrode comprising
an electrically conductive shell defining and surrounding a hollow
electrode chamber;
said precipitator inlet communicating into said electrode
chamber;
said shell having a plurality of narrow slot openings therethrough
connecting said electrode chamber with said precipitator chamber,
thereby forming a plurality of small size outlets for both gaseous
sample and the particulate impurities which are charged by the high
potential field around said high potential electrode;
whereby the particulate impurities are accelerated out of said
electrode chamber and are flung against said low potential
electrode.
2. In the electrostatic precipitator of claim 1, the improvement
further comprising,
said shell having a top and a bottom portion near the respective
top and bottom portions of said electrode chamber;
said slot openings being only through said shell top portion,
whereby heavier particulate impurities can settle to the bottom of
said electrode chamber without being able to exit therefrom, while
lighter particulate impurities can exit.
3. A conditioner for removing particulate and liquid impurities
from a gaseous sample, comprising,
an inlet for said conditioner, said inlet leading to an inlet for a
first stage through which the gaseous sample moves; and an outlet
from said conditioner;
a first stage including an upper hollow cylindrical chamber and a
lower hollow chamber, with said upper chamber being located
directly over said lower chamber, thereby forming a single
continuous chamber; said single chamber being defined by a
surrounding wall; said lower chamber comprising an inwardly,
downwardly, tapered chamber having a lower end;
said conditioner inlet leading into said upper chamber near the
upper end thereof and aimed so that the sample moves around the
interior of said wall surrounding said continuous hollow chamber
and so that the sample moves down through said continuous chamber
toward said lower end of said lower chamber whereby the impurities
whirl around said wall and become separated from the sample;
said first stage having an outlet, including a conduit extending
into said continuous chamber and having an entry port spaced away
from said wall around said continuous chamber and also away from
said lower end of said lower chamber, thereby to draw the already
conditioned gaseous sample out of said continuous chamber;
a trap communicating with the said lower end of said lower chamber
and being filled with a liquid which catches and holds particulate
impurities and liquid impurities which have moved through said
continuous chamber and contacted the liquid; said lower end of said
lower chamber being submerged in said liquid;
a second stage having an inlet connected with said outlet of said
first stage; said second stage including a chamber having a first
and second electrode within it, said electrodes being spaced-apart
and electrically insulated from one another; said first electrode
being connected to a high electric potential and said second
electrode being connected to a lower electric potential thereby
creating a high potential drop across said electrodes, whereby
particulate impurities passing through said second stage are
electrically charged and are electrically attracted and cling to
said second electrode and whereby liquid impurities are caused to
be vaporized; said second stage having an outlet;
pump means having an inlet connected with said outlet from said
second stage, and having an outlet connected with the inlet to a
sample dividing means, for drawing gaseous sample through said
first and second stages and for pumping gaseous sample through the
dividing means and out said continuous outlet;
said pump means operating upon said continuous chamber of said
first stage to keep said continuous chamber at slightly reduced
pressure, said pump means further serving to cause the liquid
within said trap to move into said lower chamber of said continuous
chamber a distance proportional to the pressure reduction, whereby
said continuous chamber and said trap combine to form a
manometer;
a gaseous sample dividing means having an inlet and a first outlet;
the inlet thereof communicating with said pump means outlet and
said dividing means first outlet leading to said conditioner
outlet;
said dividing means having a second outlet, so that only that part
of the gaseous sample which is needed to pass through said
conditioner outlet is able to do so and the rest of said sample can
pass through said second flow dividing means outlet;
said gaseous sample dividing means has a closed upper end and an
open lower end; said sample dividing means inlet and said first
outlet therefrom communicating near said upper end thereof and said
second outlet thereof communicating with said open lower end
thereof and being vented to the outside.
4. The conditioner for a gaseous sample of claim 3, wherein said
second electrode comprises a wall spaced away from and surrounding
said first electrode;
said first electrode comprises an electrically conductive shell
defining and surrounding a hollow electrode chamber; said shell
having a top and bottom portion near the respective top and bottom
portions of said electrode chamber;
said second stage inlet communicating into said electrode
chamber;
said shell top portion having a plurality of narrow slot openings
therethrough connecting said electrode chamber with said second
stage chamber, thereby forming a plurality of small size outlets
from said electrode chamber for both the gaseous sample and the
electrically charged particulate impurities whereby the particulate
impurities are accelerated out of said electrode chamber and are
flung against said second electrode;
said second stage outlet communicating with said second stage
chamber.
5. The conditioner for a gaseous sample of claim 4, further
including
said conditioner inlet communicating with a chimney for receiving
gaseous sample holding impurities requiring conditioning;
a sample preconditioner for cooling the gaseous sample before it
enters said first stage inlet; said preconditioner moving a gaseous
sample inlet communicating with said conditioner inlet and a
gaseous sample outlet communicating with said first stage inlet;
said preconditioner including a cooling chamber through which said
gaseous sample passes;
said preconditioner cooling chamber having a pool of liquid therein
for trapping particles which settle into the pool and for trapping
liquid impurities which condense in said cooling chamber; and an
impurity removal conduit communicating with said pool in said
cooling chamber for permitting removal of impurities from said
pool;
cooling means communicating with said cooling chamber for cooling
said cooling chamber and the gaseous sample therein; said cooling
means comprises a jacket around said cooling chamber; said jacket
having a cooling medium passed into it;
said conditioner inlet having heating means positioned with respect
to it to heat the gaseous sample as and before it moves into the
conditioner inlet;
an impurity removal conduit communicating with said impurity trap
of said first stage for permitting removal of impurities trapped in
said trap;
an adjustable flow volume control means between said pump outlet
and said flow divider means inlet for varying the flow along the
path between these elements.
6. The conditioner for a gaseous sample of claim 3, further
including
said conditioner inlet communicating with a chimney for receiving
gaseous sample holding impurities requiring conditioning;
a sample preconditioner for cooling the gaseous sample before it
enters said first stage inlet; said preconditioner having a gaseous
sample inlet communicating with said conditioner inlet and a
gaseous sample outlet communicating with said first stage inlet;
said preconditioner including a cooling chamber through which said
gaseous sample passes;
said preconditioner cooling chamber having a pool of liquid therein
for trapping particles which settle into the pool and for trapping
liquid impurities which condense in said cooling chamber; and an
impurity removal conduit communicating with said pool in said
cooling chamber for permitting removal of impurities from said
pool;
cooling means communicating with said cooling chamber for cooling
said cooling chamber and the gaseous sample therein; said cooling
means comprises a jacket around said cooling chamber; said jacket
having a cooling medium passed into it;
said conditioner inlet having heating means positioned with respect
to it to heat the gaseous sample as and before it moves into the
conditioner inlet.
7. A conditioner for removing particulate and liquid impurities
from a gaseous sample, comprising,
an inlet for said conditioner, said inlet leading into an inlet for
a first stage through which the gaseous sample moves;
a first stage including a hollow chamber surrounded by a wall; said
conditioner inlet leading into the upper end of said hollow chamber
and being aimed so that the gaseous sample moves around the
interior of said wall and down through said hollow chamber whereby
the impurities whirl around said wall and become separated from the
sample; said first stage having an outlet leading to the inlet of a
second stage;
a second stage having an inlet connected with said outlet of said
first stage; said second stage including a chamber having a first
and second electrode within it, said electrodes being spaced-apart
and electrically insulated from one another;
said first electrode being connected to a high electric potential
and comprising an electrically conductive shell defining and
surrounding a hollow electrode chamber; said shell having a top and
bottom portion near the respective top and bottom portions of said
electrode chamber;
said second stage inlet communicating into said electrode
chamber;
said shell top portion having a plurality of narrow slot openings
therethrough connecting said electrode chamber with said second
stage chamber, thereby forming a plurality of small size outlets
from said electrode chamber for both the gaseous sample and the
electrically charged particulate impurities, whereby the
particulate impurities are accelerated out of said electrode
chamber and are flung against said second electrode;
said second electrode being connected to a lower electric potential
thereby creating a high potential drop across said electrodes, said
second electrode comprising a wall spaced away from and surrounding
said first electrode;
whereby particulate impurities passing through said second stage
are electrically charged and are electrically attracted and cling
to said second electrode and whereby liquid impurities are caused
to be vaporized;
said second stage having an outlet leading from said second
electrode wall;
said conditioner having an outlet; means joining said second stage
outlet to said conditioner outlet, from which conditioner outlet
the now conditioned gaseous sample can pass to where it is to be
operated upon.
8. A conditioner for removing particulate and liquid impurities
from a gaseous sample, comprising,
an inlet for said conditioner, said inlet leading into an inlet for
a first stage through which the gaseous sample moves;
a first stage including an upper hollow cylindrical chamber and a
lower hollow chamber, with said upper chamber being located
directly over said lower chamber, thereby forming a single
continuous chamber; said single chamber being defined by a
surrounding wall; said lower chamber comprising an inwardly,
downwardly tapered chamber;
said conditioner inlet leading into said upper chamber near the
upper end thereof and aimed so that the gaseous sample moves around
the interior of said wall surrounding said continuous hollow
chamber and so that the sample moves down through said continuous
chamber, whereby the impurities whirl around said wall and become
separated from the sample;
said first stage having an outlet;
a trap communicating with the lower end of said lower chamber for
collecting impurities which have moved through said continuous
chamber; said trap being filled with a liquid which catches and
holds particulate impurities and liquid impurities which contact
it;
the path from said conditioner inlet to said conditioner outlet
comprises a flow path through said conditioner; pump means
connected into the flow path through said conditioner for moving
gaseous sample through said conditioner; said pump means being
positioned past said first stage outlet to operate upon said
continuous chamber to keep said continuous chamber at slightly
reduced pressure;
said pump means further serving to cause the liquid within said
trap to move into said lower chamber of said continuous chamber a
distance proportional to the pressure reduction, whereby said
continuous chamber and said trap combine to form a manometer;
a second stage having an inlet connected to said outlet of said
first stage; said second stage including a chamber having a first
and a second electrode within it, said electrodes being
spaced-apart and electrically insulated from one another; said
first electrode being connected to a high electric potential and
said second electrode being connected to a lower electric potential
thereby creating a high potential drop across said electrodes,
whereby particulate impurities passing through said second stage
are electrically charged and are electrically attracted and cling
to said second electrode and whereby liquid impurities are caused
to be vaporized; said second stage having an outlet;
said conditioner having an outlet; means joining said second stage
outlet to said conditioner outlet, from which conditioner outlet
the now conditioned gaseous sample can pass to where it is to be
operated upon;
a gaseous sample dividing means having an inlet communicating with
said pump means output, and a first outlet leading to said
conditioner outlet;
said gaseous sample dividing means having a second outlet so that
only that part of the gaseous sample which is needed to pass
through said conditioner outlet is able to do so and the rest of
said sample can pass through said second dividing means outlet.
9. A conditioner for removing particulate and liquid impurities
from a gaseous sample, comprising,
an inlet for said conditioner, said inlet leading into an inlet for
a first stage through which the gaseous sample moves;
a first stage including an upper hollow cylindrical chamber and a
lower hollow chamber, with said upper chamber being located
directly over said lower chamber, thereby forming a single
continuous chamber; said single chamber being defined by a
surrounding wall; said lower chamber comprising an inwardly,
downwardly tapered chamber;
said conditioner inlet leading into said upper chamber near the
upper end thereof and aimed so that the gaseous sample moves around
the interior of said wall surrounding said continuous hollow
chamber and so that the sample moves down through said continuous
chamber, whereby the impurities whirl around said wall and become
separated from the sample;
said first stage having an outlet;
a second stage having an inlet connected to said outlet of said
first stage; said second stage including a chamber having a first
and second electrode within it, said electrodes being spaced-apart
and electrically insulated from one another; said first electrode
being connected to a high electric potential and said second
electrode being connected to a lower electric potential thereby
creating a high potential drop across said electrodes, whereby
particulate impurities passing through said second stage are
electrically charged and are electrically attracted and cling to
said second electrode and whereby liquid impurities are caused to
be vaporized; said second stage having an outlet;
said conditioner having an outlet; means joining said second stage
outlet to said conditioner outlet, from which conditioner outlet
the now conditioned gaseous sample can pass to where it is to be
operated upon;
a gaseous sample dividing means having an inlet communicating with
said second stage outlet, and a first outlet leading to said
conditioner outlet;
said gaseous sample dividing means having a second outlet, so that
only that part of the gaseous sample which is needed to pass
through said conditioner outlet is able to do so and the rest of
said sample can pass through said second flow dividing means
outlet;
said gaseous sample dividing means has a closed upper end and an
open lower end; said sample dividing means inlet and said first
outlet therefrom communicating near said upper end thereof and said
second outlet thereof communicating with said open lower end
thereof and being vented to the outside.
Description
This invention relates to a conditioner for a gaseous sample and,
more particularly, to a conditioner for removing particulate and
liquid impurities from a gaseous sample.
Gaseous samples are often analyzed or otherwise operated upon.
Frequently, these gaseous samples contain particulate and/or liquid
impurities which should be removed before the gaseous sample is
operated upon. For example, if smoke, and particularly smoke from a
chimney, is being analyzed for the presence of a particular
component, e.g., sulfur dioxide, waste and impurities, e.g. ash
particles and water vapor, should be removed from the gaseous
sample before it is analyzed, because the impurities may affect the
result of the analysis, and will coat both the conduits leading to
the analyzing apparatus and the interior of the analyzing apparatus
causing deterioration in the effectiveness of the analyzing
apparatus. In addition, the impurities may contaminate the reagent
used in the analyzing apparatus which would both prevent it from
properly performing its function during analysis and affect the
results of the analysis. To prevent interference with the analysis
process, the gaseous sample should be conditioned to remove
particulate and/or liquid impurities. The present invention
provides a self-contained gaseous sample conditioner.
In addition, where the analyzing apparatus is intended to be
portable, it is desirable to also have the sample conditioner
portable to be readily moved to where it is needed, e.g., adjacent
a chimney, the smoke emanating from which is being tested. The
present invention provides a compact, readily portable gaseous
sample conditioner.
The novel conditioner includes a pump means for moving gaseous
sample through the conditioner from its inlet to its outlet so that
the sample might be treated. The pump means may be of any type, but
is preferably of a type which is designed to protect the sample
being pumped from contacting the internal mechanism of the pump
means which might contaminate the sample with lubricant or other
materials in the pump mechanism. The pump means may be located
anywhere along the flow path through the conditioner. The reasons
for its placement at particular locations will be discussed
below.
The conditioner has an inlet which leads into the initial stage of
the conditioner. This initial stage, at the option of the designer
of the conditioner, may comprise a sample preconditioner, e.g. a
sample cooling and dehumidifying chamber. As the particular
application may require, the preconditioner might be used to heat,
rather than cool, the sample or to add or remove a component, for
example. One contemplated use for the present invention is in
analysis of smoke and other emanations from a chimney. These
materials will be heated when they exit from the chimney. It may be
desirable to keep the sample heated until it first enters the
conditioner because a change in temperature in the sample while it
is traveling through the inlet conduits into the conditioner might
change its chemical composition undesirably or the cooling of the
sample as it travels toward the conditioner may cause some of the
impurities to precipitate out of the sample and coat the walls of
the inlet conduits, undesirably occluding these conduits which are
not so readily cleaned out as the conditioning apparatus itself. If
the heated transmission line from the sample source to the sample
conditioner is used, the preconditioner is required to reduce the
temperature of the sample before it enters the conditioner. If, on
the other hand, the sample from sample source 10 is not heated
either by the sample source or by heating means, and if the sample
has cooled before it enters the conditioner, or if the temperature
of the sample is not critical, then there is no need for the
preconditioner.
Assume there is a need for a preconditioner. It is comprised of a
cooling chamber, which is merely a large hollow chamber through
which the sample travels. The hollow chamber is surrounded by a
jacket filled with cooling material, e.g. flowing water, which
reduces the temperature of the contents of the hollow chamber. At
the base of the hollow chamber is a water trap, e.g. a pool of oil.
As the gaseous sample is cooled, the water in the sample condenses
and is trapped by the water trap in the cooling chamber.
The next stage in the conditioner, if the sample preconditioner is
used, or the first stage in the conditioner if, at the option of
the designer, the sample cooling stage is not used, is a first
chamber that includes means which cause separation of the
particulate impurities from the gaseous sample. The inlet to the
first chamber is aimed first, to direct the gaseous sample to move
around the interior wall of the first chamber and second, to move
the sample downward, so that impurities and the gaseous sample move
in a descending spiral. The lower section of the first chamber may
be inwardly downwardly, i.e. conically, tapered so that the
particles passing through this section are greatly accelerated.
A trap may be provided which communicates with the lower end of the
first chamber to trap the particulate and liquid impurities which
contact it. The trap may be filled with a liquid bath, e.g., an oil
bath, which serves to trap the particles as described.
When the water or other liquid impurities contact and are trapped
by the oil bath, these heavier and denser liquid impurities settle
through the oil bath and form a pool beneath it, whereby the oil
bath trap does not deteriorate because of water and other dense
liquid impurities mixing into it.
The liquid-filled trap cooperates with the first chamber to act as
a manometer. The pump means, described above, may be downstream of
the first chamber. If the pump is so positioned, it draws the
gaseous sample into, through and out of the first chamber, thereby
causing a slight pressure reduction in the chamber, as compared
with atmospheric pressure. The reduced chamber pressure permits the
pressure on the surface of the liquid in the trap to force some of
the liquid up into the lower end of the first chamber. The greater
the pressure reduction, the higher the liquid from the trap will
rise. The liquid level is calibratable in terms of the chamber
pressure, whereby a manometer is formed.
The conduits leading from the sample source, into the conditioner
initial stage, if one is used, and into the first chamber of the
first stage carry untreated gaseous sample which has a relatively
large quantity of particulate and liquid impurities suspended in
it. Consequently, these conduits are most likely to be the ones
obstructed or blocked by a buildup of impurities in them. As the
obstruction becomes progressively greater, the pump means will be
able to draw gaseous sample only at a lesser flow volume rate.
Accordingly, the pressure in the first chamber will be
progressively reduced and this will cause the liquid from the trap
to move further up into the first chamber.
The first chamber may have a gauge or meter on it to indicate the
height of the liquid from the trap in the first chamber. When the
height of the liquid exceeds a predetermined level, the obstruction
to the inflow of gaseous sample into the first chamber has become
so great that there cannot be a sufficient volume gaseous sample
output from the conditioner. At this time, by checking the gauge,
an operator would know that the conduits leading into the first
chamber must be cleared of obstructions.
The outlet from the first chamber draws gaseous sample out of the
center of the first chamber because the heavier impurities are
traveling around the periphery of the chamber. This may readily be
accomplished by having an outlet conduit extending into the center
of the first chamber. A conduit leads from the first chamber into
the inlet of the second chamber which holds an electrostatic
precipitator. An electrostatic precipitator has two spaced-apart
electrodes with a high electric potential drop across them. As the
gaseous sample passes through the electrostatic precipitator, the
particulate impurities become charged by one of the electrodes and
are attracted to and cling to the other of the electrodes, whereby
they are removed from the gaseous sample.
Any liquid impurities still remaining in the sample are electrical
resistors in the high potential electric field and are vaporized
and dispersed within the precipitator.
Desirably, the electrostatic precipitator consists of a hollow
chamber surrounded by a wall comprised of a conductive material,
which wall serves as one electrode. Within the chamber, e.g., at
the center thereof, is the other electrode. It is the electrode at
the higher potential and particulate impurities are either
contacted or influenced by the field surrounding this electrode and
are charged thereby. In a preferred form, the high potential
electrode itself is a shell defining a smaller chamber within the
hollow chamber of the electrostatic precipitator. The inlet to the
precipitator opens into the small chamber defined by the central
electrode. The shell has a plurality of thin slots passing through
it around its periphery near its upper end. The charged particles
can exit from the chamber within the shell of the electrode to
travel toward the outer electrode, only by passing through the
slots. The lower end of the small chamber is closed. The gaseous
sample enters the precipitator near the top of the small interior
chamber. The heavier particulate impurities settle to the bottom of
the interior chamber. The smaller particulate impurities are
ionized by the high potential of the central electrode and fly away
from the central electrode toward the low potential electrode with
a high velocity, due to the small exit area presented by the slots
through the shell of the central electrode. More of the smaller
particles, than with known precipitators, adhere to the low
potential outer wall of the precipitator because they are flung
against that wall and because of the attraction of the wall for the
charged particles.
The outlet conduit from the electrostatic precipitator has its
entry port near the higher potential electrode, which is the
electrode that the charged impurities move away from, and is
located where the gaseous sample is least contaminated.
The pump means described above, may be either upstream or
downstream of the electrostatic precipitator. In a preferred
embodiment, the pump means is downstream of the precipitator and is
connected with its outlet. By being downstream of both the first
and second chambers, the pump is not contacted by gaseous sample
until the sample has been decontaminated. The pump, therefore, is
freed from having to have deposits of impurities cleaned out of it.
The pump usually would not include means for conditioning or
cleaning the gaseous sample, and there is no reason to position it
where it will be unnecessarily contaminated without helping to
clean the sample.
A gaseous sample flow dividing means may be provided downstream of
the pump. A first outlet from the flow dividing means would be
connected with the inlet to the apparatus which analyzes or
otherwise operates upon the conditioned gaseous sample. This
apparatus requires that gaseous sample pass to it at a
predetermined flow rate. Presumably, this apparatus will draw
gaseous sample into it at the predetermined rate so long as the
conditioner can provide sample at that rate.
The flow divider also has a second outlet, which may be connected
to the outside or to a waste receptacle. Unneeded conditioned
gaseous sample passes out the second outlet.
It is expected and unavoidable that the conduits leading into and
through the conditioner will become coated and partially obstructed
with particulate impurities as the conditioner continues to
operate. Therefore, the conditioner is designed to pass through
itself and condition a greater volume of sample than would be
required by the apparatus receiving conditioned sample from the
conditioner. As the conditioner continues to operate and its flow
rate decreases, there is still enough gaseous sample produced for
the apparatus requiring it. Eventually, of course, the conditioner
will cease to produce the required minimum of sample. But, with
excessive sample being produced, the conditioner may be left
unattended for a longer period of time than would be the case if it
were designed to produce only the minimum sample flow rate, in
which case the conduits of the conditioner would have to be
frequently cleaned.
Accordingly, it is a primary object of the present invention to
provide a conditioner for removing impurities from a gaseous
sample.
It is another object of the present invention to provide such a
conditioner which is compact, lightweight, and portable.
It is another object of the present invention to provide such a
conditioner which may be left unattended for an extended period of
time.
It is another object of the present invention to provide such a
conditioner having a minimum of stages and components.
It is another object of the present invention to provide such a
conditioner which can properly operate for prolonged period as the
conduits leading into and through the conditioner become
progressively coated with and obstructed by the impurities in the
gaseous sample being conditioned.
It is another object of the present invention to provide such a
conditioner which includes a gauge which indicates whether the
conduits leading into the conditioner have become so obstructed as
to preclude the conditioner from producing an adequate flow of
conditioned gaseous sample.
It is another object of the invention to provide a novel
electrostatic precipitator for removing impurities from a gaseous
sample.
These and other objects of the present invention will become
apparent when the following description is read in conjunction with
the accompanying drawing in which:
FIG. 1 schematically illustrates one embodiment of the present
invention;
FIG. 2 is a front elevation of a conditioner designed in accordance
with the invention; and
FIG. 3 is a side elevation of the conditioner of FIG. 2 in the
direction of arrows 3.
Identical elements in each of the Figures are identically numbered.
As shown in FIGS. 2 and 3, the conditioner schematically
illustrated in FIG. 1 can be placed in a compact and readily
portable housing.
Referring to the Figures, the gaseous sample conditioner of the
present invention is used for removing particulate and liquid
impurities from a gaseous sample. A source of sample to be
conditioned is chimney 10 out of which flows smoke containing the
gaseous sample and various solid and liquid impurities, including
ash and water. Another source of gaseous sample may be used. The
sample passes to the conditioner which removes the solid and liquid
impurities and thereafter, the sample passes to an apparatus 12
which operates upon the sample.
For example, it may be desired to determine the sulfur dioxide
content of the emission from chimney 10. The apparatus 12 would
comprise an analyzer for analyzing the gaseous sample for the
presence of sulfur dioxide. Such analyzer is shown in copending
application Ser. No. 728,306, filed May 10, 1968, now U.S. Pat. No.
3,493,857 in the name of John Silverman, entitled "Analyzer Using
an Operational Amplifier," and assigned to the assignee hereof. The
analyzer should not be contaminated with particulate or liquid
impurities which may coat the surfaces of containers and conduits
within the analyzer and prevent their properly functioning and
which may mix with the gaseous sample and with the analyzing
reagent, thereby adversely affecting the reaction.
The conditioner of the present invention includes a housing 13 in
which all of the conditioner components are mounted and in which
are located all of the component connecting conduits.
The conditioner has a pump 14 which draws gaseous sample into the
conditioner and toward and through the pump, and then pumps the
gaseous sample out of the conditioner. Pump 14 may be at any
location in the flow path through the conditioner between the first
stage 56, to be described, of the conditioner and the flow dividing
means 130, to be described. The further downstream in the flow path
that the pump is located, the less it will be exposed to and
contaminated with the impurities carried by the gaseous sample.
Since the pump is not designed to remove impurities, it should be
downstream where it cannot be contaminated. The pump sucks or draws
gaseous sample through those components of the conditioner which
are upstream of it and pumps gaseous sample through those
components which are downstream of it.
Pump 14 may be any conventional pump for pumping a gaseous sample.
Preferably, it is of a type designed to protect the gaseous sample
moving through it from contacting the operating mechanism of the
pump, which may contaminate the gaseous sample with impurities like
lubricant or scrapings from the pump components. Pump 14 is shown
as a diaphragm pump which includes an airtight sealed chamber 16
having one wall which is comprised of a flexible impermeable
diaphragm 18. The diaphragm includes a mounting post 20 outside
chamber 16 to which is pivotally connected at 22 a connecting rod
24 which is, in turn, pivotally connected at 26 eccentrically to a
disc 28 which rotates around drive shaft 30. Motor means 31 rotates
shaft 30 and disc 28, which causes rod 24 to move pivot 22, and
hence, diaphragm 18 up and down, as viewed in FIG. 1, thereby
reciprocatingly increasing and decreasing the volume of chamber
16.
Pump inlet and outlet ball check valves 34 and 40, respectively,
ensure that the flow through pump 14 is only in the downstream
direction. Valve 34 has a valve seat 35 with an opening
therethrough which permits gaseous sample to travel into chamber
16. The ball 36 is pressed by elevated pressure within chamber 16,
due to a decrease in the chamber volume, against its valve seat 35,
whereby no gaseous sample within the chamber 16 can return
upstream. A screen 37 permeable by gaseous sample keeps ball 36
near its valve seat 35 when chamber 16 is increasing in volume and
sample is being drawn into the pump.
Valve 40 includes a valve seat 42 facing in the opposite direction
to seat 35 and includes a ball 44 which sits on seat 42. When
diaphragm 18 is moving downward and chamber 16 is increasing in
size, ball 44 is drawn to seat 42 and prevents any sample
downstream of the pump from being drawn upstream. Screen 46, which
is permeable by sample, holds ball 44 in position near seat 42.
Moving now to the upstream end of the conditioner, the conditioner
has an inlet 50 which is connected with the chimney 10 to draw some
of the chimney emission into the conditioner. As pump 14 operates,
the emission passes through the conditioner inlet 50, through
conduit 51, through fitting 52 on the wall of housing 13, through
conduit 53 in housing 13 and out exit 54 of conduit 53 into the
preconditioner 200. As was noted above, the preconditioner may be
used at the option of the operator to cool the emission from the
sample source. The gaseous sample in conduits 51, 53 is at an
elevated temperature due to the heat generated within the chimney.
As a further option for the designer, if the preconditioner 200 is
to be used, the conduits 51 and/or 53 may be heated by heating
means 202 and/or 204 which would heat up or keep heated the sample
exiting from sample source 10. The heated sample passes through
conduit 53 and exits therefrom through its outlet 54 into the
vacant chamber 206 of the preconditioner 200. At the bottom of the
vacant chamber 206 is a pool 208 of oil or other water and impurity
entrapping material, for reasons to be described. Chamber 206 is
enclosed by wall 210 which is surrounded by an enclosed jacket 212
which holds a cooling medium, such as water. The contents of jacket
212 are always kept segregated from the contents of chamber 206 so
that there will be no contamination. If water is the cooling
medium, an inlet 214 from a conventional cool water supply empties
into jacket 212. The jacket becomes filled with cool water. Spent
cooling water exits from jacket 212 through exit conduit 216 and
passes to waste. The cooling water reduces the interior temperature
of chamber 206 thereby cooling the gaseous sample then in the
chamber. As the sample cools, some of the water and liquid
impurities in the sample condense and are trapped by the pool 208
of oil. The dense water settles through the oil pool 208 and forms
a separate water pool 220 beneath the oil. An outlet conduit 222
communicates with the base of chamber 206 and the impurity water in
pool 220 can be periodically withdrawn from chamber 206 through
conduit 222. Some of the heavier solid impurities will settle
through chamber 206 and be trapped by the oil pool 208. Once the
sample has been cooled in chamber 206 and some of the liquid and
solid impurities have been removed therefrom, the sample is drawn
by the sucking action of pump 14 through the exit conduit 224 of
conditioner 200 and travels through conduit 224.
The first stage comprises a first chamber 58, 64. Upper hollow
cylindrical chamber 58 is sealed at its upper end 60 and has an
open lower end 62. Disposed directly beneath cylindrical chamber 58
is a downwardly inwardly, conically tapered, hollow chamber 64,
having an open upper end 66 which is sealed at 68 with the lower
open end 62 of chamber 58, and having an open lower end 70 which is
submerged a short distance into the liquid 72 within the impurity
trap 74, to be described further below. Chamber 58, 64 is
conventionally referred to as a cyclone.
Conduit outlet 54 opens into upper chamber 58 near its upper end 60
and is directed so as to blow the entering gaseous sample
substantially tangentially against the interior wall 76 of chamber
58. Outlet conduit 54 is also aimed to blow the sample slightly
downward. The sample with the impurities suspended in it,
therefore, whirls around wall 76 in a downward spiral.
As the impurities whirl downward through chamber 64, they are
accelerated both around the interior wall and downward due to the
decreasing diameter of chamber 64. Eventually, the impurities
strike the pool 72 of liquid trapping medium within trap 74 and are
trapped by the liquid. Pool 72 is preferably an oil bath which
traps particulate impurities. Liquid impurities, which mostly
comprise water, are trapped in the oil. Being heavier and denser
than the oil, the liquid impurities pass through the oil and form a
pool 80 beneath it. Thus, the efficiency of the oil bath as a trap
is not diminished by having water impurity mixed into it. An outlet
conduit 82 may be connected with the lower end of trap 74. The
outlet conduit may be a permanent water runoff line, or it may have
a stop cock 84 on it which is periodically opened to open conduit
82 and permit the pool 80 of water and other liquid impurities to
be removed.
The reason for filling the impurity trap 74 with a liquid trapping
medium, such as oil, is to enable the first stage of the
conditioner 56 to operate as a monometer, or gas pressure sensing
gauge. Pump 14, while operating, is drawing gaseous sample through
first stage 56, and is therefore, sucking gaseous sample out of the
chamber 58, 64. Chamber 58, 64 is at a slightly reduced pressure,
as compared with outside pressure. Otherwise, no sample would be
drawn into the chamber from chimney 10. As was noted above, the
lower end 70 of tapered chamber 64 is submerged in pool 72. The
reduced pressure in chamber 58, 64 causes the level 90 of pool 72
within tapered chamber 64 to rise above the level of the liquid
within the rest of trap 74. This is because of the above noted
pressure difference. As the pressure difference increases, level 90
rises.
Pump 14 pumps gaseous sample at a continuous rate. The conduits 51,
53 are directly exposed to the emission from chimney 10 and conduit
224, if preconditioner 200 is used, is less directly exposed. These
are the conduits most likely to become internally coated with
particulate impurities and to become eventually obstructed or
blocked. As conduits 51, 53, 224 become progressively more
obstructed, the rate of flow, i.e. flow volume per unit time, of
gaseous sample into chamber 58, 64 is reduced. The constant pumping
rate of pump 14 cooperates with the progressive obstruction of
conduits 51, 53 to continuously decrease the gas pressure within
chamber 56, and thereby causes the level 90 of liquid within
tapered chamber 64 to continuously rise.
A height gauge 92 for the liquid level 90 in tapered chamber 64 is
provided. If the chamber 64 is made of transparent material, the
height gauge can consist of visible graduation marks on the
exterior of the chamber 64. Any other conventional liquid height
gauge may be used. When the pressure within pressure chamber 58, 64
decreases below a predetermined level, as measured on gauge 92, the
obstruction of conduits 51, 53 is too severe for the conditioner to
properly operate. At that time, the conditioner may be stopped and
conduits 51, 53 may be cleaned out. Conduits 51, 53 should be
sufficiently wide that it takes a prolonged period before they
become so obstructed with impurities as to cause the conditioner to
cease to operate properly. Consequently, the conditioner will be
operable for an extended period without requiring that its conduits
be cleaned.
Passing through the closed end 60 of upper cylindrical chamber 58
is an outlet conduit 94 which extends downward into the center of
chamber 58. The particulate and liquid impurities travel around the
interior wall 76 of chamber 58, 64. Consequently, the centered
position of outlet conduit 94 keeps it away from the impurities, so
that less contaminated gaseous sample is drawn from chamber 58, 64.
The pressure at the center of chamber 58, 64 is lower than that at
the periphery thereof, due to the vortex caused by the downwardly
spiralling gaseous sample and impurities. However, pump 14 is able
to draw enough gaseous sample out of the conditioner first stage 56
to cause proper operation.
The gaseous sample drawn out of first stage 56 travels through
conduit 96, into inlet conduit 98 at the top of the second stage
100 of the conditioner. The second stage 100 comprises an
electrostatic precipitator for precipitating out of the gaseous
sample any remaining particulate impurities and for vaporizing and
thereby eliminating the liquid impurities. The precipitator
comprises a hollow cylinder 101 having closed top and bottom ends
102 and 103, respectively. This forms a precipitator chamber.
Cylinder 101 has two electrodes 104, 105 in it with a high electric
potential drop across them. The particulate impurities are charged
in the electric field generated by the high potential electrode
104, to be described in more detail below, are attracted and cling
to the lower potential electrode 105 and are thereby removed from
the gaseous sample. The liquid impurities are resistors in the
electric potential field surrounding the high potential electrode,
are vaporized by the high potential and are dispersed, so that
their subsequent effect on the gaseous sample is minimized.
As illustrated, the interior wall 105 surrounding cylinder 101 is
comprised of electrically conductive material, is electrically
grounded at 106 and serves as the low potential electrode in the
precipitator to which the charged particulate impurities cling.
Extending into the center and part way down through the cylinder
101 is high potential electrode 104, which may be a simple carbon
electrode or a more efficient electrode, which will be described
below. The high potential electrode is connected by conductor 107
to a high electric potential power supply 108, whereby a high
potential electric field is established in and around the electrode
104 and within cylinder 101.
The preferred and more efficient form of high potential electrode
is illustrated in FIG. 1. The electrode 104 comprises a hollow
shell 109 which is preferably cylindrical, and which cylindrical
shell is comprised of an electrically conductive material. Shell
109 defines an electrode chamber within itself. The upper end 110
of the shell is sealed closed. Passing through the sealed upper end
is the lead 107 from high potential source 108 which lead is
electrically connected to the shell 109. Also passing through the
sealed end 110 and opening into the upper end of the electrode
chamber within shell 109 is the outlet from second stage inlet
conduit 98. Thus, the partially conditioned gaseous sample from the
first stage of the conditioner initially enters the electrode
chamber within cylinder 109. Shell 109 is sealed closed at its
lower end by a sealing plug 111.
A plurality of small size, spaced-apart slots 112 pass completely
through the shell 109. The slots 112 start near the upper end of
shell 109, are located all around the periphery of the cylinder and
extend downward along the upper portion of the shell. The slots
preferably do not extend all the way down through the lower portion
of the shell for reasons to be described.
Gaseous sample, carrying liquid and particulate impurities, enters
the electrode chamber within shell 109. The liquid and water
impurities are vaporized by the high potential and disperse. All of
the particulate material entering this chamber is ionized by the
high electric potential of electrode 104. The heavier particles
drift down through the electrode chamber past slots 112 and
eventually settle on the upper surface of sealing plug 111. Once
the heavier particles move past the lowermost ones of slots 112,
they are no longer able to move out of the electrode chamber.
Locating slots 112 along the upper portion of shell 109 precludes
heavier impurity particles from drifting out of shell 109, whereby
they no longer can be carried along by the flow of gaseous
sample.
As the gaseous sample flows into the electrode chamber within shell
109, it flows out of the only exit available to it, namely the
plurality of slots 112, thereby filling the precipitator chamber
within cylinder 101 with gaseous sample. The light weight
electrically charged particles of particulate impurities which do
not settle past slots 112 are electrically repelled by the high
potential of the electrode 104 and are attracted by the low
potential of electrode 105. The only avenue of escape for these
particles are the narrow slots 112 out of the electrode chamber.
Due to these particles being highly charged and due to their
continuously entering the electrode chamber, once the particles
move adjacent the small slots 112, they are propelled out with
great velocity. In addition, because slots 112 are narrow and
spaced-apart, the gaseous sample carrying the particles rushes
through the slots with considerable speed and force. The particles
of particulate impurities, therefore, are propelled out of the
electrode chamber formed within shell 109 with great force arising
from the combination of the repulsion by electrode 104, the
attraction by the interior cylinder wall forming electrode 105, the
force of the exiting gaseous sample and the narrow and few in
number avenues of escape. The escaping waste particles are thrown
against the electrode 105 with considerable force, whereby they
readily adhere to the lower potential electrode. In this manner,
the electrostatic precipitator 100 efficiently removes particulate
waste from a gaseous sample.
The electrostatic precipitator here described in detail is useful
not only in the particular apparatus shown herein but is generally
useful in any application requiring the removal of particulate
wastes from a gaseous sample.
The electrostatic precipitator 100 specifically described above
with its novel high potential electrode is more efficient than a
conventional electrostatic precipitator employing a solid high
potential electrode. For example, it has been found that with a
solid carbon high potential electrode, in order for one embodiment
of the gaseous sample conditioner of the present invention to
operate properly, the electrostatic precipitator must be operated
at a potential of approximately 12,000 volts. However, the same
sample conditioner, using the novel electrostatic precipitator
described herein, can operate efficiently at a potential of
approximately 7,000-- 8,000 volts.
The conditioned gaseous sample within cylinder 101 is drawn by pump
14 through outlet conduit 114 and into pump inlet conduit 116.
Outlet conduit 114 is centered in lower end 103 of cylinder 101.
Being centered, it is away from the cylinder wall 105 of the
precipitator and is thereby away from the surface to which the
particulate impurities are clinging, whereby the conduit 114 draws
cleaner gaseous sample from the cylinder 101.
The gaseous sample travels through pump inlet conduit 116, through
pump 14, which was described above, and then out pump outlet
conduit 118. The gaseous sample next passes a flow volume
controlling means, e.g. needle valve 120, which can partially or
totally block conduit 118 and thereby control the volume of
conditioned gaseous sample which will pass to the apparatus 12. The
conduit 118 continues at 122 downstream of the flow volume
controlling means.
Conduit 122 has an outlet 124 into the flow dividing means 130
which apportions the flow of conditioned gaseous sample so that
sample flows at a proper rate to the apparatus 12. As illustrated,
the outlet 124 enters near the top of the hollow upper cylindrical
chamber 132 which with the hollow conically tapered lower chamber
134 forms a single hollow chamber.
A large volume of conditioned gaseous sample travels through
conduit 122 and into the flow dividing means 130. The apparatus 12
may include a means (not shown) for drawing the gaseous sample
required by the apparatus out of the flow dividing means 130. The
pump 14 lends additional help in pumping the gaseous sample to the
apparatus 12. The portion of the sample required by apparatus 12
exits through exit conduit 136 which extends into the chamber 132,
134. It travels through fitting 138 on housing 13 and through
conduit 139 to apparatus 12.
It is expected that during operation of the conditioner, certain of
its conduits and components will become coated with impurities
which obstruct the flow of gaseous sample to a progressively
greater extent, thereby progressively reducing the flow rate of
gaseous sample. Therefore, the conditionaer is designed so that the
flow rate of gaseous sample into flow dividing means 130 is greater
than the sample flow rate required by apparatus 12. For example,
the conditioner could be producing sample at a flow rate of 5
liters per minute, when the conditioner is producing at maximum
output, while the apparatus 12 only requires sample at a flow rate
of 0.2 liters per minute. The excess gaseous sample produced by the
conditioner, but not used by the apparatus 12, progressively
decreases in flow rate as the conditioner becomes obstructed. But,
because excess sample is produced, the flow rate to apparatus 12
can remain constant. Hence, by producing an excess of gaseous
sample, the conditioner can be operated for a long period of time
without being checked or cleaned by an operator, whereby many man
hours are thereby saved.
In view of there being excess sample produced, a portion of the
gaseous sample moving into flow dividing means 130 cannot be used
by the apparatus 12 and will not exit through exit conduit 136.
Chamber 132, 134 is vented through conduit 140 to the outside or
into a closed vessel at or near atmospheric pressure so that there
is no pressure buildup within the chamber 132, 134 which might
establish a back pressure that would interfere with proper
operation of the conditioner. The apparatus 12 always draws off
sample at a constant flow rate which it requires for its operation.
It is only the excess gaseous sample that is vented through conduit
140.
There has just been described a conditioner for a gaseous sample
for removing particulate and liquid impurities from the gaseous
sample before passing the sample on to an apparatus which operates
upon or uses the now impurity free sample. The conditioner
optionally uses a novel electrostatic precipitator which was also
described.
Although there has been described a preferred embodiment of this
novel invention, many variations and modifications will now be
apparent to those skilled in the art. Therefore, this invention is
to be limited, not by the specific disclosure herein, but only by
the appended claims.
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