CA1216616A - Apparatus for dispensing an abrasive into a gas stream - Google Patents
Apparatus for dispensing an abrasive into a gas streamInfo
- Publication number
- CA1216616A CA1216616A CA000414035A CA414035A CA1216616A CA 1216616 A CA1216616 A CA 1216616A CA 000414035 A CA000414035 A CA 000414035A CA 414035 A CA414035 A CA 414035A CA 1216616 A CA1216616 A CA 1216616A
- Authority
- CA
- Canada
- Prior art keywords
- gas stream
- particles
- supply
- propelling
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
- B24C7/0092—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts the abrasive material being fed by mechanical means, e.g. by screw conveyors
Abstract
APPARATUS AND PROCESS FOR DISPENSING
AN ABRASIVE INTO A GAS STREAM
Abstract of the Disclosure Particles are passed into a propellling gas stream in a controlled manner regardless of variations in the counter-pressure that may exist at the discharge end of the supply line for said particle-entrained propelling gas stream. The pressure in the propelling gas stream, at a point intermediate the injection point of said particles and the upstream control means for said gas stream, is equalized with the supply con-tainer for said particles, providing direct, self-compensating pressure equalization facilitating the controlled passage of particles from the supply container to said propelling gas stream. A conveyor belt is conveniently employed to transport particles from the supply container to the injection point of the particles into said propelling gas stream. The particle-entrained gas stream can readily be injected into small diameter heat exchanger tubes, larger furnace tubes, pipelines or other conduits to be treated by said particles entrained in a propelling gas stream.
AN ABRASIVE INTO A GAS STREAM
Abstract of the Disclosure Particles are passed into a propellling gas stream in a controlled manner regardless of variations in the counter-pressure that may exist at the discharge end of the supply line for said particle-entrained propelling gas stream. The pressure in the propelling gas stream, at a point intermediate the injection point of said particles and the upstream control means for said gas stream, is equalized with the supply con-tainer for said particles, providing direct, self-compensating pressure equalization facilitating the controlled passage of particles from the supply container to said propelling gas stream. A conveyor belt is conveniently employed to transport particles from the supply container to the injection point of the particles into said propelling gas stream. The particle-entrained gas stream can readily be injected into small diameter heat exchanger tubes, larger furnace tubes, pipelines or other conduits to be treated by said particles entrained in a propelling gas stream.
Description
r APPARATUS AND PROVES S
FOR DISPENSING AN ABRASIVE INTO A GAS STREAM
Background of the Invention Field of the Invention The invention relates to the dispensing of particles into a gas stream.
Description of the Prior Art Apparatus Apparatus comprising a gas supply line, means for controlling the extent of the stream of gas, a supply container for particles, such as abrasives, dispensing means coupled to the gas supply line, and a discharge line for discharging the gas stream laden with particles is generally known in the art. Such apparatus is disclosed in Dutch Patent Application No. 7708990, and is designed for cleaning and/or decoying the interior of pipelines, tubes or other conduits. For this purpose, the stream of gas laden with abrasive is introduced into the pipeline to be cleaned by means of a suitable injection head, the abrasive impinging on the pipe wall to be cleaned at a high radial velocity owing to turbulential and vertical components in the stream of gas. For the cleaning of pipes, use can be made of abrasive materials having sharp edges, such as sand and steel grit, but abrasive or cleaning materials in the form of steel balls, i.e. steel shot, or other cleaning materials, can also be employed.
It has been found that the decoying and cleaning of such pipelines having a relatively large diameter, as to be found in hydrocarbon furnaces in refineries and the like, can be achieved in a 1367~
I
particularly effective way, it being possible for such pipelines to be internally stripped of every kind of deposits. It has also been found, however, that the cleaning of pipelines having a small diameter, i.e. on the order of one or a few centimeters, is often impossible or impractical, using available apparatus because the small amount of abrasive or other cleaning materials that must be supplied to the stream of gas for the cleaning of these pipelines cannot be properly dosed using the available apparatus. In fact, in prior art apparatus, the abrasive is dosed by means of a plate provided with a suitable aperture that would have to be so small, for the quantity of abrasive required for cleaning thin, i.e. small diameter, pipelines and tubes, that the aperture would immediately become clogged with abrasive.
Small diameter pipelines and tubes, however, are very widely used as, for example, in existing heat exchangers in refineries and processing industries. In these heat exchanger pipes, carbonaceous, corrosion and/or chemical precipitate layers can be deposited in the course of time, adversely affecting heat trays or and material flow. Accordingly, such layers must be removed after some period of use. Pipe banks in heat exchangers have hitherto been cleaned typically by means of water under high pressure. One disadvantage of this technique is that cleaning with water generally leaves residues of the layers in the tubes. Another disadvantage is that the water issues with great force from the end of the pipe bank, said water being greatly contaminated, and causing a major water burden.
lo Lowe It is, accordingly, an object of the present invention to provide an apparatus and process for dispensing an abrasive or other cleaning materials into a stream of gas, whereby it is possible to accurately dose small quantities of abrasive into the gas stream.
It is another object of the invention to provide an improved apparatus and process for metering a controlled amount of abrasive or other cleaning material into a propelling gas stream.
Summary of the Invention For such purposes, the invention provides an apparatus and process in which the dispensing means may comprise a conveyor means to which an abrasive or other particles can be supplied from a container, the conveyor means being capable of transporting the abrasive to a supply orifice in the gas supply line. A pressure equalizing conduit is positioned between the interior of the container and the gas supply line, the equalizing conduit being coupled with the gas supply line at a point intermediate the propelling gas control means and the particle supply orifice.
Brief Description of the Drawings The invention will be described hereinbelow, by way of example, with reference to the accompanying drawings relating to a particular embodiment of the invention in which:
Fig. 1 shows a diagrammatic elevation Al view of an embodiment of the dispensing apparatus according to the invention;
1367~
Fig. 2 shows a cross-sectional view of a detail of Fig. l; and Fig. 3 is an elevation Al view taken on line III-III of Fig. 2.
Detailed Description of the Invention It has been found that, by controlling the rate of circulation of a conveyor belt, it is possible to supply even the smallest possible desired quantity of abrasive or other particles to a propelling gas stream in a highly accurate, reproducible manner. In cleaning the piping in a heat exchanger or in other cleaning applications, a stream of gas is subject to a varying counter-pressure in the discharge conduit of the apparatus for every pipe or conduit being cleaned.
It is necessary to provide means for ensuring that, nevertheless, the correct quantity of abrasive or other particles can be supplied to the gas stream regardless of every possible counter-pressure. For this purpose, there is provided a direct, self-compensating, equalizing conduit coupled, on the one hand, to the interior of the particle supply container and, on the other hand, to the gas supply line at a point intermediate the propelling gas control means and the supply orifice for the abrasive or other particles. A portion of the gas from the total gas stream flows in the equalizing conduit, which gas is thus supplied to the container. Inasmuch as the pressure at the point where the equalizing conduit is coupled to the gas supply line will be a little higher than the pressure at the point of the supply orifice for the abrasive or other particles, a minor gas stream is generated from the particle supply container to the supply orifice This minor gas stream ensures that, irrespective of the counter-pressure experienced, abrasive or other particles can be continually supplied to the propelling stream of gas.
In Fig. 1, a gas supply line, designated by the numeral I is connected to a source of gas (not shown) for supplying a suitable propelling gas, e.g.
nitrogen or air, stream for the abrasives or other cleaning particles. Provided in gas supply line 1 are, successively, a shut-off valve 2, a control valve 3/ and aperture plate 4. Furthermore, a pressure gauge 5 is coupled to the line intermediate control valve 3 and the aperture plate 4. The aperture plate 4 is dimensioned so that a critical pressure is generated, so that the position of control valve 3 is proportional to the velocity of the gas. Connected to line 1 at some distance from aperture 4 is a particle supply inlet 6 for the supply of abrasive or other particles. This supply inlet preferably tapers towards line 1.
A particle container 7 for abrasive or other cleaning materials is closed at the top in a gas-tight manner, by means of a cover. Container 7 desirably has a funnel-shaped bottom to optimize flow of the abrasive Connected to the bottom of the container is supply conduit 8, which terminates a short distance above a conveyor belt 9, which is preferably channel-shaped. The shape of conveyor belt 9, and the shape of the mouth of the supply conduit, are best shown in Figures 2 and 3, which illustrate details of the area where the supply conduit terminates at the conveyor belt.
I
Conveyor belt 9 may be connected in the usual way with a prime mover, such as a motor, for movement over two pulleys 10 and 11. In operation, belt 9 circulates in a clock-wise direction, as viewed in Fig. 1. The right-hand pulley 11 is so positioned that the point where the abrasive or other particles lying on the belt leaves the same under the influence of gravity is located over the center of supply orifice 6 in gas line 1. The supply conduit 8, conveyor belt 9 and pulleys 10 and 11 are all housed in a gas-tight housing coupled at the top with particle container 7 and at the bottom terminating in the, preferably tapered, supply orifice 6.
In order to ensure that, at any counter-pressure encountered at the effluent end of line 1, the desired quantity of abrasive or other particles is supplied to the gas stream, there is provided an equalizing conduit 13. Conduit 13 is connected, on the one hand, with the interior of said container 7, preferably at the top thereof, and, on the other hand, with the gas supply line 1, at a location intermediate the supply orifice 6 and the aperture plate 4. Equalizing conduit 13 preferably terminates in gas line 1 with a mouth located in the direction of flow of the gas, so that the conduit captures a little of the gas supplied.
As a result, via the equalizing conduit, a pressure can be generated within container 7, said pressure being a little higher than the pressure in conduit 1 adjacent to supply orifice 6. The result is a positive pressure for the introduction of the abrasive or other particles into the stream of gas, independent of the counter-pressure experienced by the gas. Those skilled in the art will appreciate that the counter-pressure is determined by the diameter and the degree of fouling of the pipe being cleaned. The particle supply orifice 6 preferably also terminates in supply line 1 via a mouth extending at an angle, whereby the abrasive or other particles are essentially supplied in the direction of flow of the gas. Vortices adjacent to the abrasive supply inlet orifice are thereby substantially prevented.
In order that abrasive or other particles may be supplied from the container to the conveyor belt without any problems even at low velocities of the conveyor belt, it has been determined that it is beneficial-to bevel the end of supply conduit 8 relative to the supporting surface of the conveyor belt, as is clearly shown in Figures 2 and 3.
It has been found that, by means of the dispensing apparatus according to the invention, even small quantities of abrasive or other particles can be supplied to a stream of gas in a highly accurate manner. The quantity of abrasive to be dispensed depends on the gas throughput, and can be controlled by adapting the velocity of the conveyor belt. The propelling gas laden with abrasive or other particles is supplied via a discharge conduit, not shown, to a suitable injection nozzle.
It has also been found that by means of the apparatus and process of the invention, pipes having a diameter ranging between 0.5 and 7.5 cm can be cleaned in an extremely effective manner without there being any residual carbonaceous, corrosion and/or precipitate layers in the pipes.
13~78 Although the invention has been described in the foregoing with reference to an exemplary embodiment it is noted that the invention is not so limited to the particular details of the illustrated embodiment. Various modifications can be made without departing from the scope of the invention For example, various means, well known to those skilled in the art, can be used for the control of the gas stream in gas line 1, and for delivering particles from container 7 to particle supply orifice 6. In place of conveyor belt 9, for example, a transporting wheel, mounted for rotation under supply conduit 8 and provided with recesses along its circumference for receiving particles and transporting said particles to supply orifice 6, can be employed. For this purpose the transporting wheel must be capable of rotating in the same plane as, e.g. pulley 10. It will be appreciated that other means can be utilized for the delivery of particles in a controlled manner from container 7 to particle supply orifice 6. When employed, the conveyer belt may be flat instead of channel shaped, and there are also various obvious design alternatives for the shape of container 7, supply conduit 8, and supply orifice 6.
The invention as disclosed herein can be used to effectively control the rate at which abrasives or other cleaning materials, or other desired particles, are metered into a propelling gas stream. While the invention is particularly advantageous in the metering of small quantities of particles into propelling gas streams for injection into small diameter heat exchanger tubes and the like, it will be appreciated that the invention can also be advantageously employed for the controlled injection of cleaning materials into propelling gas streams for introduction into larger sized furnace tubes to be decoyed and cleaned, pipelines to be cleaned and dried, and other such applications in which the direct, self-compensating pressure equalizing conduit described above can assure that a desired quantity of particles can be supplied to a propelling gas stream regardless of the varying counter-pressure that may be operative in the downstream pipe or other conduit into which the article entrained propelling gas stream is being introduced through a discharge conduit and injection head. The invention thus enhances the effectiveness of the use of particles entrained in a gas stream in such applications, by insuring that a controlled quantity of particles can be employed in a desired manner in accordance with established procedures and experience pertaining to the treatment of such tubes, pipelines or other conduits.
FOR DISPENSING AN ABRASIVE INTO A GAS STREAM
Background of the Invention Field of the Invention The invention relates to the dispensing of particles into a gas stream.
Description of the Prior Art Apparatus Apparatus comprising a gas supply line, means for controlling the extent of the stream of gas, a supply container for particles, such as abrasives, dispensing means coupled to the gas supply line, and a discharge line for discharging the gas stream laden with particles is generally known in the art. Such apparatus is disclosed in Dutch Patent Application No. 7708990, and is designed for cleaning and/or decoying the interior of pipelines, tubes or other conduits. For this purpose, the stream of gas laden with abrasive is introduced into the pipeline to be cleaned by means of a suitable injection head, the abrasive impinging on the pipe wall to be cleaned at a high radial velocity owing to turbulential and vertical components in the stream of gas. For the cleaning of pipes, use can be made of abrasive materials having sharp edges, such as sand and steel grit, but abrasive or cleaning materials in the form of steel balls, i.e. steel shot, or other cleaning materials, can also be employed.
It has been found that the decoying and cleaning of such pipelines having a relatively large diameter, as to be found in hydrocarbon furnaces in refineries and the like, can be achieved in a 1367~
I
particularly effective way, it being possible for such pipelines to be internally stripped of every kind of deposits. It has also been found, however, that the cleaning of pipelines having a small diameter, i.e. on the order of one or a few centimeters, is often impossible or impractical, using available apparatus because the small amount of abrasive or other cleaning materials that must be supplied to the stream of gas for the cleaning of these pipelines cannot be properly dosed using the available apparatus. In fact, in prior art apparatus, the abrasive is dosed by means of a plate provided with a suitable aperture that would have to be so small, for the quantity of abrasive required for cleaning thin, i.e. small diameter, pipelines and tubes, that the aperture would immediately become clogged with abrasive.
Small diameter pipelines and tubes, however, are very widely used as, for example, in existing heat exchangers in refineries and processing industries. In these heat exchanger pipes, carbonaceous, corrosion and/or chemical precipitate layers can be deposited in the course of time, adversely affecting heat trays or and material flow. Accordingly, such layers must be removed after some period of use. Pipe banks in heat exchangers have hitherto been cleaned typically by means of water under high pressure. One disadvantage of this technique is that cleaning with water generally leaves residues of the layers in the tubes. Another disadvantage is that the water issues with great force from the end of the pipe bank, said water being greatly contaminated, and causing a major water burden.
lo Lowe It is, accordingly, an object of the present invention to provide an apparatus and process for dispensing an abrasive or other cleaning materials into a stream of gas, whereby it is possible to accurately dose small quantities of abrasive into the gas stream.
It is another object of the invention to provide an improved apparatus and process for metering a controlled amount of abrasive or other cleaning material into a propelling gas stream.
Summary of the Invention For such purposes, the invention provides an apparatus and process in which the dispensing means may comprise a conveyor means to which an abrasive or other particles can be supplied from a container, the conveyor means being capable of transporting the abrasive to a supply orifice in the gas supply line. A pressure equalizing conduit is positioned between the interior of the container and the gas supply line, the equalizing conduit being coupled with the gas supply line at a point intermediate the propelling gas control means and the particle supply orifice.
Brief Description of the Drawings The invention will be described hereinbelow, by way of example, with reference to the accompanying drawings relating to a particular embodiment of the invention in which:
Fig. 1 shows a diagrammatic elevation Al view of an embodiment of the dispensing apparatus according to the invention;
1367~
Fig. 2 shows a cross-sectional view of a detail of Fig. l; and Fig. 3 is an elevation Al view taken on line III-III of Fig. 2.
Detailed Description of the Invention It has been found that, by controlling the rate of circulation of a conveyor belt, it is possible to supply even the smallest possible desired quantity of abrasive or other particles to a propelling gas stream in a highly accurate, reproducible manner. In cleaning the piping in a heat exchanger or in other cleaning applications, a stream of gas is subject to a varying counter-pressure in the discharge conduit of the apparatus for every pipe or conduit being cleaned.
It is necessary to provide means for ensuring that, nevertheless, the correct quantity of abrasive or other particles can be supplied to the gas stream regardless of every possible counter-pressure. For this purpose, there is provided a direct, self-compensating, equalizing conduit coupled, on the one hand, to the interior of the particle supply container and, on the other hand, to the gas supply line at a point intermediate the propelling gas control means and the supply orifice for the abrasive or other particles. A portion of the gas from the total gas stream flows in the equalizing conduit, which gas is thus supplied to the container. Inasmuch as the pressure at the point where the equalizing conduit is coupled to the gas supply line will be a little higher than the pressure at the point of the supply orifice for the abrasive or other particles, a minor gas stream is generated from the particle supply container to the supply orifice This minor gas stream ensures that, irrespective of the counter-pressure experienced, abrasive or other particles can be continually supplied to the propelling stream of gas.
In Fig. 1, a gas supply line, designated by the numeral I is connected to a source of gas (not shown) for supplying a suitable propelling gas, e.g.
nitrogen or air, stream for the abrasives or other cleaning particles. Provided in gas supply line 1 are, successively, a shut-off valve 2, a control valve 3/ and aperture plate 4. Furthermore, a pressure gauge 5 is coupled to the line intermediate control valve 3 and the aperture plate 4. The aperture plate 4 is dimensioned so that a critical pressure is generated, so that the position of control valve 3 is proportional to the velocity of the gas. Connected to line 1 at some distance from aperture 4 is a particle supply inlet 6 for the supply of abrasive or other particles. This supply inlet preferably tapers towards line 1.
A particle container 7 for abrasive or other cleaning materials is closed at the top in a gas-tight manner, by means of a cover. Container 7 desirably has a funnel-shaped bottom to optimize flow of the abrasive Connected to the bottom of the container is supply conduit 8, which terminates a short distance above a conveyor belt 9, which is preferably channel-shaped. The shape of conveyor belt 9, and the shape of the mouth of the supply conduit, are best shown in Figures 2 and 3, which illustrate details of the area where the supply conduit terminates at the conveyor belt.
I
Conveyor belt 9 may be connected in the usual way with a prime mover, such as a motor, for movement over two pulleys 10 and 11. In operation, belt 9 circulates in a clock-wise direction, as viewed in Fig. 1. The right-hand pulley 11 is so positioned that the point where the abrasive or other particles lying on the belt leaves the same under the influence of gravity is located over the center of supply orifice 6 in gas line 1. The supply conduit 8, conveyor belt 9 and pulleys 10 and 11 are all housed in a gas-tight housing coupled at the top with particle container 7 and at the bottom terminating in the, preferably tapered, supply orifice 6.
In order to ensure that, at any counter-pressure encountered at the effluent end of line 1, the desired quantity of abrasive or other particles is supplied to the gas stream, there is provided an equalizing conduit 13. Conduit 13 is connected, on the one hand, with the interior of said container 7, preferably at the top thereof, and, on the other hand, with the gas supply line 1, at a location intermediate the supply orifice 6 and the aperture plate 4. Equalizing conduit 13 preferably terminates in gas line 1 with a mouth located in the direction of flow of the gas, so that the conduit captures a little of the gas supplied.
As a result, via the equalizing conduit, a pressure can be generated within container 7, said pressure being a little higher than the pressure in conduit 1 adjacent to supply orifice 6. The result is a positive pressure for the introduction of the abrasive or other particles into the stream of gas, independent of the counter-pressure experienced by the gas. Those skilled in the art will appreciate that the counter-pressure is determined by the diameter and the degree of fouling of the pipe being cleaned. The particle supply orifice 6 preferably also terminates in supply line 1 via a mouth extending at an angle, whereby the abrasive or other particles are essentially supplied in the direction of flow of the gas. Vortices adjacent to the abrasive supply inlet orifice are thereby substantially prevented.
In order that abrasive or other particles may be supplied from the container to the conveyor belt without any problems even at low velocities of the conveyor belt, it has been determined that it is beneficial-to bevel the end of supply conduit 8 relative to the supporting surface of the conveyor belt, as is clearly shown in Figures 2 and 3.
It has been found that, by means of the dispensing apparatus according to the invention, even small quantities of abrasive or other particles can be supplied to a stream of gas in a highly accurate manner. The quantity of abrasive to be dispensed depends on the gas throughput, and can be controlled by adapting the velocity of the conveyor belt. The propelling gas laden with abrasive or other particles is supplied via a discharge conduit, not shown, to a suitable injection nozzle.
It has also been found that by means of the apparatus and process of the invention, pipes having a diameter ranging between 0.5 and 7.5 cm can be cleaned in an extremely effective manner without there being any residual carbonaceous, corrosion and/or precipitate layers in the pipes.
13~78 Although the invention has been described in the foregoing with reference to an exemplary embodiment it is noted that the invention is not so limited to the particular details of the illustrated embodiment. Various modifications can be made without departing from the scope of the invention For example, various means, well known to those skilled in the art, can be used for the control of the gas stream in gas line 1, and for delivering particles from container 7 to particle supply orifice 6. In place of conveyor belt 9, for example, a transporting wheel, mounted for rotation under supply conduit 8 and provided with recesses along its circumference for receiving particles and transporting said particles to supply orifice 6, can be employed. For this purpose the transporting wheel must be capable of rotating in the same plane as, e.g. pulley 10. It will be appreciated that other means can be utilized for the delivery of particles in a controlled manner from container 7 to particle supply orifice 6. When employed, the conveyer belt may be flat instead of channel shaped, and there are also various obvious design alternatives for the shape of container 7, supply conduit 8, and supply orifice 6.
The invention as disclosed herein can be used to effectively control the rate at which abrasives or other cleaning materials, or other desired particles, are metered into a propelling gas stream. While the invention is particularly advantageous in the metering of small quantities of particles into propelling gas streams for injection into small diameter heat exchanger tubes and the like, it will be appreciated that the invention can also be advantageously employed for the controlled injection of cleaning materials into propelling gas streams for introduction into larger sized furnace tubes to be decoyed and cleaned, pipelines to be cleaned and dried, and other such applications in which the direct, self-compensating pressure equalizing conduit described above can assure that a desired quantity of particles can be supplied to a propelling gas stream regardless of the varying counter-pressure that may be operative in the downstream pipe or other conduit into which the article entrained propelling gas stream is being introduced through a discharge conduit and injection head. The invention thus enhances the effectiveness of the use of particles entrained in a gas stream in such applications, by insuring that a controlled quantity of particles can be employed in a desired manner in accordance with established procedures and experience pertaining to the treatment of such tubes, pipelines or other conduits.
Claims (22)
1. An improved apparatus for dispensing particles into a propelling gas stream comprising:
(a) a propelling gas supply line subject to varying counter-pressure at the discharge end thereof, resulting from conditions pertaining in a downstream conduit into which said propelling gas stream entrained with particles is to be dis-charged;
(b) control means for controlling the flow of gas in said supply line, said control means including an apertured plate capable of generating a pressure in said supply line and a valve upstream of the apertured plate for control-ling the velocity of the propelling gas in said supply line;
(c) a supply container for particles to be dispensed into said propelling gas stream;
(d) dispensing means for supplying a controlled quantity of particles from said supply container to said gas supply line; and (e) a pressure equalizing conduit com-municating between the interior of said supply container and said gas supply line, said pressure equalizing conduit being positioned in said supply line at a point intermediate said apertured plate and the point downstream at which said dispensing means supplies particles to said gas supply line, the pressure at the point where the equalizing conduit is coupled to the gas supply line being a little higher than the pressure at the point at which said dispensing means supplies particles to said gas supply line, said pressure equalizing conduit being adapted to pass a small portion of the total propelling gas stream to said supply container; whereby a controlled quantity of particles can be dispensed into the propelling gas stream regardless of variations that may exist in the counter-pressure at the discharge end of the gas supply line.
(a) a propelling gas supply line subject to varying counter-pressure at the discharge end thereof, resulting from conditions pertaining in a downstream conduit into which said propelling gas stream entrained with particles is to be dis-charged;
(b) control means for controlling the flow of gas in said supply line, said control means including an apertured plate capable of generating a pressure in said supply line and a valve upstream of the apertured plate for control-ling the velocity of the propelling gas in said supply line;
(c) a supply container for particles to be dispensed into said propelling gas stream;
(d) dispensing means for supplying a controlled quantity of particles from said supply container to said gas supply line; and (e) a pressure equalizing conduit com-municating between the interior of said supply container and said gas supply line, said pressure equalizing conduit being positioned in said supply line at a point intermediate said apertured plate and the point downstream at which said dispensing means supplies particles to said gas supply line, the pressure at the point where the equalizing conduit is coupled to the gas supply line being a little higher than the pressure at the point at which said dispensing means supplies particles to said gas supply line, said pressure equalizing conduit being adapted to pass a small portion of the total propelling gas stream to said supply container; whereby a controlled quantity of particles can be dispensed into the propelling gas stream regardless of variations that may exist in the counter-pressure at the discharge end of the gas supply line.
2. The apparatus of Claim 1 in which said dispensing means comprises a conveyor belt adapted to transport particles supplied thereon from said supply container at a controlled rate to a supply orifice in communication with the interior of said supply line.
3. The apparatus of Claim 2 and including a supply conduit for passing particles from said supply container to said conveyor belt.
4. The apparatus of Claim 2 and including means for controlling the rate of circulation of said conveyor belt.
5. The apparatus of Claim 3 in which said supply conduit terminates a small distance above said conveyor belt.
6. The apparatus of Claim 5 in which said conveyor belt is a channel-shaped belt, said supply conduit terminating a small distance above the bottom of said channel-shaped belt.
7. The apparatus of Claim 6 in which said supply conduit terminates at an acute angle relative to the bottom of said channel-shaped belt.
8. The apparatus of Claims 2 or 3 in which said supply orifice for dispensing particles into the propelling gas stream in said supply line in tubular and tapers inward in the direction of said supply line.
9. The apparatus of Claims 1 or 2 in which said pressure equalizing conduit terminates in said gas supply line with its mouth portion facing upstream in the direction of gas flow in said gas supply line so as to facilitate capture of a small portion of the propelling gas passing through said line.
10. The apparatus of Claims 1 or 2 in which said pressure equalizing conduit extends to the top portion of said supply container.
11. The apparatus of Claims 1 or 2 in which said propelling as supply line contains an injeciton nozzle at the downstream end thereof.
12. The apparatus of Claim 2 in which said injection nozzle is adapted to inject particle-entrained gas to the interior of said downstream conduit to be treated by said particles.
13. The apparatus of Claim 12 in which said downstream conduit comprises pipes having a diameter of from about 0.5 to about 7.5 cm.
14. The apparatus of Claim 13 in which said downstream conduit comprises heat exchanger tubes.
15. An improved process for dispensing particles into a propelling gas stream comprising:
(a) maintaining a propelling gas stream in a line subject to varying counter-pressure at the discharge end thereof, resulting from conditions pertaining to a downstream conduit into which said propelling gas stream entrained with particles is being discharged;
(b) passing a controlled quantity of said particles from a supply container to said propelling gas stream;
(c) controlling the flow of gas in said propelling gas stream at a point upstream from the point at which said particles are passed into said propelling gas stream, with an apertured plate positioned upstream from said point at which said particles are passed into the propelling gas stream generating a pressure in said line and a control valve upstream of said apertured plate controlling the velocity of the propelling gas stream in said line;
(d) equalizing the pressure between the supply container and said propelling gas stream at an intermediate point between the point at which said particles are passed into said gas stream and the upstream point at which the flow of gas in said propelling gas stream is controlled, the pressure at the intermediate point being a little higher than the pressure at the point at which said particles pass into the gas stream, said pressure equalizing comprising direct fluid communication between said propelling gas stream and said supply container, with a small portion of the propelling gas stream being passed to said supply container, whereby a controlled quantity of particles can be passed into the propelling gas stream regardless of variations that may exist in the counter-pressure at the downstream end of said propelling gas stream.
(a) maintaining a propelling gas stream in a line subject to varying counter-pressure at the discharge end thereof, resulting from conditions pertaining to a downstream conduit into which said propelling gas stream entrained with particles is being discharged;
(b) passing a controlled quantity of said particles from a supply container to said propelling gas stream;
(c) controlling the flow of gas in said propelling gas stream at a point upstream from the point at which said particles are passed into said propelling gas stream, with an apertured plate positioned upstream from said point at which said particles are passed into the propelling gas stream generating a pressure in said line and a control valve upstream of said apertured plate controlling the velocity of the propelling gas stream in said line;
(d) equalizing the pressure between the supply container and said propelling gas stream at an intermediate point between the point at which said particles are passed into said gas stream and the upstream point at which the flow of gas in said propelling gas stream is controlled, the pressure at the intermediate point being a little higher than the pressure at the point at which said particles pass into the gas stream, said pressure equalizing comprising direct fluid communication between said propelling gas stream and said supply container, with a small portion of the propelling gas stream being passed to said supply container, whereby a controlled quantity of particles can be passed into the propelling gas stream regardless of variations that may exist in the counter-pressure at the downstream end of said propelling gas stream.
16. The process of Claim 15 in which particles are passed from said supply container to a conveyor belt from which said particles are supplied at a controlled rate to a supply orifice for injection into the propelling gas stream.
17. The process of Claim 16 in which the rate at which particles are supplied to the supply orifice is controlled by controlling the rate of circulation of the conveyor belt.
18. The process of Claim 15 in which the pressure is equalized between said propelling gas stream and the top portion of said supply container.
19. The process of Claim 15 and including passing the particle-entrained propelling gas stream to an injection nozzle at the downstream end of the line containing said propelling gas stream.
20. The process of Claim 19 and including injecting said particle-entrained gas through said injection nozzle to the interior of said downstream conduit to be treated by said particles.
21. The process of Claim 20 in which said downstream conduit comprises pipes having a diameter of from about 0.5 to about 7.5 cm.
22. The process of Claim 21 in which said downstream conduit comprises heat exchanger tubes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8104940 | 1981-10-30 | ||
| NL8104940A NL8104940A (en) | 1981-10-30 | 1981-10-30 | DEVICE FOR DOSING AN ABRASIVE IN A GAS FLOW. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1216616A true CA1216616A (en) | 1987-01-13 |
Family
ID=19838300
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000414035A Expired CA1216616A (en) | 1981-10-30 | 1982-10-22 | Apparatus for dispensing an abrasive into a gas stream |
Country Status (8)
| Country | Link |
|---|---|
| BE (1) | BE894863A (en) |
| CA (1) | CA1216616A (en) |
| DE (1) | DE3240120A1 (en) |
| ES (1) | ES516992A0 (en) |
| FR (1) | FR2515558B1 (en) |
| GB (1) | GB2108399B (en) |
| IT (1) | IT1153605B (en) |
| NL (1) | NL8104940A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2772464B2 (en) * | 1993-10-22 | 1998-07-02 | 昭和炭酸株式会社 | Powder supply unit |
| CN103707200A (en) * | 2013-12-06 | 2014-04-09 | 天津市工业搪瓷厂 | Rapid feeding device of shot blasting machine used for reaction kettle |
| CN107263332A (en) * | 2017-05-26 | 2017-10-20 | 东台市建东机械制造有限公司 | A kind of pellet transmission mechanism of numerical control compressed air shotblasting machine |
| DE102018133068B4 (en) * | 2018-12-20 | 2020-10-22 | gemeinnützige KIMW Forschungs-GmbH | Dosing device for dosing a powdery substance |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE231679C (en) * | ||||
| GB104511A (en) * | 1916-03-03 | 1917-09-27 | Carl Weller & Cie | Improvements in or relating to Spraying Apparatus more particularly for Sand Blast Machines, Whitewashing and Painting Sprayers and the like. |
| US2651404A (en) * | 1948-04-02 | 1953-09-08 | United Concrete Pipe Corp | Machine for applying coatings |
| US2569952A (en) * | 1948-07-27 | 1951-10-02 | Ian M Ridley | Cement gun apparatus |
| FR1045562A (en) * | 1949-03-14 | 1953-11-30 | Gaz De France | Method and device for the production of a compressed mixture of a fluid and a fine particle product |
| US3139705A (en) * | 1962-12-10 | 1964-07-07 | Histed Howard | Sandblast machine with precision sandfeed, remotely started and stopped |
| BE801288A (en) * | 1973-06-22 | 1973-10-15 | Soudure Autogene Elect | POWDER DISPENSER |
-
1981
- 1981-10-30 NL NL8104940A patent/NL8104940A/en active Search and Examination
-
1982
- 1982-10-22 CA CA000414035A patent/CA1216616A/en not_active Expired
- 1982-10-26 GB GB08230583A patent/GB2108399B/en not_active Expired
- 1982-10-28 IT IT23968/82A patent/IT1153605B/en active
- 1982-10-29 DE DE19823240120 patent/DE3240120A1/en not_active Withdrawn
- 1982-10-29 BE BE2/59893A patent/BE894863A/en not_active IP Right Cessation
- 1982-10-29 FR FR8218143A patent/FR2515558B1/en not_active Expired
- 1982-10-29 ES ES516992A patent/ES516992A0/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB2108399A (en) | 1983-05-18 |
| IT8223968A0 (en) | 1982-10-28 |
| GB2108399B (en) | 1985-04-24 |
| IT1153605B (en) | 1987-01-14 |
| ES8400900A1 (en) | 1983-12-01 |
| BE894863A (en) | 1983-04-29 |
| FR2515558B1 (en) | 1988-07-29 |
| NL8104940A (en) | 1983-05-16 |
| FR2515558A1 (en) | 1983-05-06 |
| DE3240120A1 (en) | 1983-05-11 |
| ES516992A0 (en) | 1983-12-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |