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US3883327A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for separating particulate matter from a gas stream

Assignee: Beloit Technologies Inc
•
Filing: 1973-05-21
•
Granted: 1975-05-13
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Expires: 1993-05-21
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Abstract

Abstract A method and apparatus for combining a particulate substance entrained in a gas stream with a substance initially present in the stream in a liquid state through controlled evaporation and recondensation of the liquid. The invention is particularly adapted for use in removing solid particle contaminants from a gas stream emanating from a dryer burning a combustible fuel. The relative volume of liquid vapor in the gas stream is maintained at a level of at least 20% to assure the presence of adequate vapor for agglomeration of particles and a relatively high saturation temperature. The gas stream, with the particles entrained therein, is passed through a first venturi wherein some initial agglomeration of particles occurs as a result of the increased mixing and liquid spray. In the diffuser section of the venturi the internal pressure of the gas stream begins to increase as the velocity decreases. Coupled with the diffuser section of the first venturi is a first frusto-conical member. As the gas stream enters the frusto-conical member the internal pressure will continue to increase until the differential between the liquid vapor pressure and the internal pressure of the gas stream is so great as to result in evaporation of the liquid. A second frusto-conical member is connected to the first member and as the gas stream enters this second member the internal pressure commences to decrease as the velocity increases. Thus, the internal pressure of the gas stream begins to approach the saturation pressure. Meanwhile, the temperature of the gas stream is being lowered through heat exchange with the walls of the members plus the liquid spray evaporation. A second venturi is coupled with the converging section of the second member and the pressure is lowered further as the gas stream enters the throat of this second venturi. The system is designed so as to approach saturation partial pressure of the gas stream liquid vapor component at the throat of the second venturi. Condensation of the liquid vapor occurs on the nuclei presented by the solid particles in the gas stream. The particles are also subjected to increased mixing in the throat of the second venturi further enhancing agglomeration. A slight increase in pressure and temperature again occurs in the diffuser section of the second venturi. The increase is not sufficient to again evaporate the absorbed liquid, however. The gas stream containing the high moisture content agglomerated particles, preconditioned for separation, may now be conveyed to a separator. The separated particles may be returned to a primary collector or to the dryer along with a stratum of the gas stream for use as the material conveying medium.

Inventors

  • 👤 Stanley P Thompson
  • 👤 Walter T Thompson
  • 👤 David L Boyert
  • 👤 Thomas B Swearingen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 23:08
CPC Classifications
B; B01; B01D; B01D47/00; B01D47/10

Claims Analysis

Total Claims: 19
Claim 1
Independent Claim 131 words
A METHOD OF COMBINING A PARTICULATE SUBSTANCE WITH A SUBSTANCE WHICH IS INITIALLY PRESENT IN A LIQUID STATE, SAID METHOD COMPRISING THE STEPS OF: MOVING THE PARTICULATE SUBSTANCE IN A FLUID STREAM; PROVIDING A QUANTITY OF SAID LIQUID SUBSTANCE IN THE FLUID STREAM; PROGRESSIVELY DECREASING THE INTERNAL FLUID STREAM PRESSURE TO THEREBY INCREASE THE VELOCITY OF THE PARTICLES OF SAID SUBSTANCE TO EFFECT AGGLOMERATION OF THE PARTICLES; MAINTAINING THE TEMPERATURE AND PRESSURE OF THE FLUID STREAM DURING SAID PROGRESSIVELY DECREASING STEP, ABOVE THE SATURATION POINT SO AS TO PRECLUDE CONDENSATION OF LIQUID DURING AGGLOMERATION OF THE PARTICLES; PROGRESSIVELY INCREASI*G THE INTERNAL FLUID STREAM PRESSURE TO EFFECT VAPORIZATION OF SAID LIQUID SUBSTANCE; AND PROGRESSIVELY REDUCING THE INTERNAL PRESSURE OF SAID FLUID STREAM TO EFFECT CONDENSATION OF THE VAPOR ON THE AGGLOMERATED PARTICLES.
Claim 2
Independent Claim 131 words
A METHOD OF COMBINING A PARTICULATE SUBSTANCE WITH A SUBSTANCE WHICH IS INITIALLY PRESENT IN A LIQUID STATE, SAID METHOD COMPRISING THE STEPS OF: MOVING THE PARTICULATE SUBSTANCE IN A FLUID STREAM; PROVIDING A QUANTITY OF SAID LIQUID SUBSTANCE IN THE FLUID STREAM; PROGRESSIVELY DECREASING THE INTERNAL FLUID STREAM PRESSURE TO THEREBY INCREASE THE VELOCITY OF THE PARTICLES OF SAID SUBSTANCE TO EFFECT AGGLOMERATION OF THE PARTICLES; MAINTAINING THE TEMPERATURE AND PRESSURE OF THE FLUID STREAM DURING SAID PROGRESSIVELY DECREASING STEP, ABOVE THE SATURATION POINT SO AS TO PRECLUDE CONDENSATION OF LIQUID DURING AGGLOMERATION OF THE PARTICLES; PROGRESSIVELY INCREASI*G THE INTERNAL FLUID STREAM PRESSURE TO EFFECT VAPORIZATION OF SAID LIQUID SUBSTANCE; AND PROGRESSIVELY REDUCING THE INTERNAL PRESSURE OF SAID FLUID STREAM TO EFFECT CONDENSATION OF THE VAPOR ON THE AGGLOMERATED PARTICLES.
Claim 3
Dependent Claim 34 words
A method as set forth in claim 1, wherein the step of progressively increasing the internal pressure comprises increasing the cross-sectional area of the fluid stream whereby to decrease the velocity of the stream.
Claim 4
Dependent Claim 33 words
A method as set forth in claim 2, wherein the step of progressively reducing internal pressure comprises decreasing the cross-sectional area of the fluid stream whereby to increase the velocity of the stream.
Claim 5
Dependent Claim 24 words
A method as set forth in claim 1, wherein is included the step of progressively reducing the temperature simultaneous with reducing the internal pressure.
Claim 6
Dependent Claim 41 words
A method as set forth in claim 4, wherein said moving step further comprises again accelerating said fluid stream subsequent to progressively increasing the internal pressure whereby to increase the turbulence in the stream and cause further agglomeration of the particles.
Claim 7
Dependent Claim 72 words
A method as set forth in claim 5, wherein is included, during the step of progressively increasing the internal pressure, the step of maintaining the temperature within the range of 5* to 20* F. above the saturation temperature of the vapor, and the step of progressively reducing the temperature and internal pressure comprises controlling the temperature and internal pressure to effect condensation simultaneously with the step of again accelerating the fluid stream.
Claim 8
Dependent Claim 49 words
A method as set forth in claim 6, wherein is included, subsequent to the step of again accelerating said fluid stream, the step of increasing the internal pressure and temperature to a level above the saturation temperature of the vapor whereby to facilitate additional movement of the fluid stream.
Claim 9
Dependent Claim 73 words
A method as set forth in claim 7, wherein said particulate substance comprises a solid and said liquid substance comprises water, and including the additional and subsequent steps of directing the fluid stream along a circuitous path to subject the agglomerated particles to centrifugal forces whereby to achieve stratification of said particles and the remainder of the fluid stream; and separating the stratum comprising said particles from the remainder of the fluid stream.
Claim 10
Dependent Claim 59 words
A method as set forth in claim 1, wherein said fluid stream comprises stack gas from a dryer utilizing a combustible fuel source, said particulate substance comprises a hygroscopic solid, said liquid substance comprises water, and wherein is included the step of maintaining the relative volume of water in the fluid stream within the range of 20 to 70%.
Claim 11
Dependent Claim 27 words
A method as set forth in claim 9, wherein the step of maintaining the relative water volume comprises introducing a quantity of water into the fluid stream.
Claim 12
Dependent Claim 103 words
A method as set forth in claim 9, wherein said particulate substance comprises a solid and said liquid substance comprises water, and including the additional and subsequent steps of directing the fluid stream along a circuitous path to subject the agglomerated particles to centrifugal forces whereby to achieve stratification oF said particles and the remainder of the fluid stream; and separating the stratum comprising said particles from the remainder of the fluid stream; and directing a portion of the separated fluid stream to the dryer inlet for use as the conveying medium to pneumatically convey a material to be dried through the dryer.
Claim 13
Dependent Claim 37 words
A method as set forth in claim 11, wherein a primary collector is provided for receiving dried material from the dryer, and including the step of directing the separated stratum comprising said particles to said primary collector.
Claim 14
Dependent Claim 29 words
A method as set forth in claim 12, wherein the step of directing the separated stratum comprises directing the stratum into the path of material entering said primary collector.
Claim 15
Dependent Claim 234 words
Apparatus for combining a solid particulate matter entrained in the stack gas of a dryer utilizing a combustable fuel with water to remove the solid matter from the gas stream said apparatus comprising: means for confining said fluid stream; first conduit structure coupled with said confining means and having a first converging section and a second diverging section, said converging section comprising converging sidewalls extending in the direction of travel of the fluid stream whereby to decrease the internal fluid stream pressure and effect agglomeration of the particles without causing the fluid stream to reach its saturation point, said diverging section comprising diverging sidewalls extending in the direction of travel of the fluid stream whereby to increase the internal fluid stream pressure to a level to effect vaporization of said liquid; and second conduit structure coupled with said first structure and having uniformly converging sidewalls extending in the direction of travel of the fluid stream whereby to decrease the internal pressure of the fluid stream to a level to cause condensation of said vapor on the agglomerated particles of said substance; a centrifugal separator coupled with the second conduit structure for achieving stratification between the particles and the remainder of the fluid stream; and third conduit means for returning a portion of the remainder of the fluid stream to the dryer inlet for use as the medium for conveying a material through the dryer.
Claim 16
Dependent Claim 234 words
Apparatus for combining a solid particulate matter entrained in the stack gas of a dryer utilizing a combustable fuel with water to remove the solid matter from the gas stream said apparatus comprising: means for confining said fluid stream; first conduit structure coupled with said confining means and having a first converging section and a second diverging section, said converging section comprising converging sidewalls extending in the direction of travel of the fluid stream whereby to decrease the internal fluid stream pressure and effect agglomeration of the particles without causing the fluid stream to reach its saturation point, said diverging section comprising diverging sidewalls extending in the direction of travel of the fluid stream whereby to increase the internal fluid stream pressure to a level to effect vaporization of said liquid; and second conduit structure coupled with said first structure and having uniformly converging sidewalls extending in the direction of travel of the fluid stream whereby to decrease the internal pressure of the fluid stream to a level to cause condensation of said vapor on the agglomerated particles of said substance; a centrifugal separator coupled with the second conduit structure for achieving stratification between the particles and the remainder of the fluid stream; and third conduit means for returning a portion of the remainder of the fluid stream to the dryer inlet for use as the medium for conveying a material through the dryer.
Claim 17
Dependent Claim 25 words
The invention of claim 14, said second conduit structure comprising a second frusto-conical member and a venturi coupled with the converging end of said member.
Claim 18
Dependent Claim 26 words
The invention of claim 14, wherein is included means for maintaining the relative water volume within the fluid stream within the range of 20 to 70%.
Claim 19
Dependent Claim 33 words
The invention of claim 16, wherein the product from the dryer is introduced into a primary collector, and including conduit means for conveying the separated stratum comprising said particulate matter to said collector.

References Cited (Backward Citations)

US2019291A Cited
US2935375A Cited
US3064408A Cited
US3212235A Cited
US3601900A Cited
US3780499A Cited
US3749382A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-05-12 1978-11-11 1979-05-13 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-05-12 1982-11-11 1983-05-13 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-05-12 1986-11-11 1987-05-13 $7700.00 Window Closed / Lapsed

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