JPH0355377B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a system for transferring large amounts of powdered material from a receiving hopper, such as a flyash dust collector hopper, to a pressurized air conveyor line. be.

Description of the Prior Art In certain industries, large quantities of powdered materials are generated. Various problems exist in orderly transferring powdered materials from units producing large quantities of such materials to transfer systems, and these problems are exacerbated by the nature of the powdered materials. This makes it extremely difficult to design a system that processes this in an orderly manner.

The most difficult problem is posed by the fly ash produced by power plants' high efficiency coal-fired furnaces and collected in precipitators. Large coal-fired power generating equipment generates a large amount of flyash. Fly ash is a substance that is extremely difficult to handle because it is as fine as heavenly pollen and extremely abrasive, and also tends to harden on the hopper and conveyor. This makes it difficult to flow such materials with reasonable uniformity into devices such as, for example, pressure-type pneumatic conveyors, which are very effective in transporting powdered materials.

(Object of the Invention) Therefore, the object of the present invention is to provide a device for flowing powder material such as flyash, which is extremely difficult to handle, into a pressure type pneumatic conveyor device with appropriate uniformity. and systems.

SUMMARY AND EFFECTS OF THE INVENTION In accordance with the present invention, powder material is transferred from a receiving hopper of a precipitator to a pressurized air conveyor line by a mechanical transfer conveyor system. The powder material falls by gravity from the mechanical transfer conveyor to the pressure mechanical conveyor, from which the powder material then flows into the pressurized air conveyor line.

The receiving hopper and mechanical transfer conveyor operate at approximately atmospheric pressure. The pressure screw conveyor, on the other hand, varies periodically between the receiving hopper pressure and a pressure equal to the pressure in the pressurized air conveyor line.

In one feed cycle, the bottom gate valve between the pneumatic conveyor and the pneumatic conveyor line is initially closed, and the gate valve between the pneumatic transfer conveyor and the pneumatic conveyor is closed. It's open. The transfer mechanism, conveyor means within the pressure mechanical conveyor and the conduits for moving the material from the receiving hopper operate continuously. At the time of receiving material within a cycle, the pressure mechanical conveyor must be at the same pressure as that of the receiving hopper and transfer conveyor, which is approximately atmospheric pressure.

At the end of the controlled material reception period to effectively fill the pressure conveyor casing, the top gate is closed, the vent valve from the pressure mechanical conveyor is closed, and the pressure in the pressure mechanical conveyor casing is increased. A pressure valve is opened to raise the pressure to the same level as the pressure in the compressed air conveyor line. Once such pressure equilibration has taken place, the bottom gate valve is opened and the continuously operating pressure conveyor mechanism transfers material from the pressure mechanical conveyor casing into the pressurized air conveyor line during the material discharge period of the cycle. to move to.

After all of the material in the pneumo-mechanical conveyor casing has been efficiently discharged, the bottom gate and pressure valve are closed and the vent valve for the pneumatic-mechanical conveyor casing is opened to return the apparatus to the receiving hopper pressure. The top gate is then opened and a new cycle begins. The cycles are controlled to efficiently and completely fill and empty the pressure mechanical conveyor casing.

In the plant, the receiving hopper is divided into two or more sets. For convenience, the acceptance hopper is described herein as being divided into two sets (and). When the pressure machine of the -A section is in the first or filling phase of the cycle, the pressure mechanical conveyor for the -B section is in the second or discharge phase of the cycle. The pneumatic mechanical conveyors of the -A and -B sections are 1/4 cycle out of phase from the operating cycle of the pneumatic mechanical conveyors of the -A and -B sections.

In addition, both ends of the pressure-mechanical conveyor casing simultaneously receive material from two conveyors, and a plurality of conveyors are provided within the casing, which convey material from both ends of the casing towards a central cross-section of the casing. and is driven to feed into the pressurized line through a bottom gate valve located at the central cross-sectional location.

The transfer conveyor mechanism and the pressure conveyor mechanism are preferably augers, and the pressure conveyor mechanism is provided with two augers spiraling in opposite directions on one axis.

Due to the above-mentioned characteristics, the system of the present invention is suitable for handling large quantities of powdered materials which are difficult to flow through equipment such as pressure-type pneumatic conveyors with reasonable uniformity and are therefore extremely difficult to handle. It is also possible to efficiently completely fill and empty the conveyor casing of the system, making it possible to efficiently and completely fill and empty the conveyor casing of the system, making it possible to efficiently fill and empty the conveyor casing of the system. This can have the effect of enabling orderly transfer from the system to the system for transferring them.

Next, a detailed explanation will be given with reference to the drawings. Referring first to FIGS. 1-5, a typical system utilizing the present invention generally consists of sets of 16 receiving hoppers each in a precipitator. Each set includes an A section of eight acceptor hoppers, each generally designated 10A; a B section of eight acceptor hoppers, each generally designated 10B; and a B section, generally designated 20A and 20B. and a transfer screw conveyor means for transferring the powder material from each receiving hopper 10A and 10B; for example, as shown generally in FIG.
a surge hopper for each said section as indicated at 0A; a pressure screw conveyor, indicated generally at 40A and 40B, for each section; a pressurized air conveyor means, indicated generally at 50; Screw conveyor 40A and 40B
To vary the air pressure within and vent the surge hoppers 30A and 30B, two air and valve systems, such as those shown generally at 60A in FIG. and a control device that operates according to the cycle. The components and arrangement of the control system are well known to those skilled in the art and detailed electrical and hydraulic circuits etc. are not believed to be necessary. It is within the ordinary skill of the art for those skilled in the art to construct a material processing system according to the present invention from the description herein and to cycle the material processing system in accordance with the requirements of FIG. You don't need anything more than technology.

1 and 3, one transfer screw conveyor means 20A moves the material from the four receiving hoppers 10A, and one pressure screw conveyor 40A or 40B connects the two transfer screw conveyors. 20A or 20B and thus each pressure screw conveyor 40A or 4
It is clear that OB processes material from eight receiving hoppers 10A or 10B.

1 and 3, the direction of movement of the fly ash above the receiving hopper row in the precipitator is indicated by arrows. The precipitator typically removes 75-85% of the fly ash contained in the gas stream flowing from right to left in FIG. Specifically, when the gas containing fly ash flows in the direction of the arrow, approximately 80% of it is removed by the rightmost receiving hopper in FIG. The removed 80% of the fly ash is then dropped into the cylindrical housing 21c, where it is conveyed from left to right in FIG. 3 to pressure screw conveyor 40A or 40B. The gas flow in the precipitator having 80% of its flyash removed, i.e. containing the remaining 20% flyash, is then transferred to the second receiving hopper from the right in FIG. fly attachment is removed. Therefore, this second receiving hopper from the right removes 16% of the flyash from the remaining 20% of the flyash and drops it into the cylindrical housing 21b. Similarly, the third receiving hopper from the right in FIG. 3 removes 3.2% fly ash from the gas flow in the precipitator, and the most downstream, leftmost receiving hopper removes 0.64% fly ash from the gas flow in the precipitator. They are respectively dropped into the cylindrical housing 21a.

With this arrangement, the largest amount of fly ash is conveyed over the shortest distance to the pressure screw conveyor 40A or 40B, while smaller amounts of fly ash are conveyed over longer distances, reducing wear on the transfer screw conveyor means 20A and 20B. It will be minimal.

Next, the structure of the various components of the system will be described. Each receiving hopper 10A and 10B consists of a conventional bin 11 for receiving ash from a fly ash collector of a coal combustion furnace in a fly ash processing system. A cutoff valve 12 is arranged at the lower end of each bottle 11 . The isolation valve 12 is connected to the transfer screw conveyor means 20 by means of an expansion joint 13.
Connected to A.

With particular reference to FIGS. 3 and 4, each transfer screw conveyor means 20A and 20B is best illustrated in FIGS. 3 and 4 and includes a series of cylindrical housings 21a, 21b and 21c, and It is provided with boxes 22a and 22b. The housing has an inlet pipe 23 that connects to the expansion joint 13. Auger shafts 24a, 24b and 24c extend over the entire length of the housings 21a, 21b and 21c, respectively, and auger shafts 24a, 24b and 24c, respectively, extend over the entire length of the housings 21a, 21b and 21c, and auger shafts 24a, 24b and 24c, respectively,
a, 25b and 25c are provided. Augers 25a and 25b overlap at transfer box 22a.

One end portion of each auger shaft 24a, 24b and 24c has a thrust bearing 26a, 26b and 26c, respectively.
The other end portion is journalled 27a, 27.
b and 27c. The end is connected to the electric motor 29
The output shafts of the gear boxes 28a, 28b and 28c are driven by gear boxes 28a, 28b and 29c. The required driving force is, of course, dependent on the length, diameter and pitch of the various augers, the specific gravity and frictional properties of the material being conveyed, and the extent to which the material being conveyed is air-floated within the conveyor housing. It will be determined depending. The horsepower rating of the electric motor will therefore be calculated individually for each system based on known engineering knowledge.

Next, referring to FIGS. 3 and 5, each surge hopper 30A and 30B is connected to the bottom supply pipe 3.
It consists of a bottle 31 with 2. Flange 33 of bottom supply tube 32 is bolted to a mating flange of transfer screw housing 21c. As shown in FIG. 3, each surge hopper bin 31 has an auger shaft 24c extending therethrough. The auger 25c terminates on the inlet side of the bin. A discharge port 34 is provided below each surge hopper bin 31 . The outlet connects via an expansion joint 35 to an upper material control gate valve, indicated generally at 36. A controlled gate valve is a device in which gate actuation is provided by any suitable pneumatic or other fluid cylinder 37.

As shown in FIG. 5, each pressure screw conveyor 40A and 40B includes a cylindrical, practically gas-tight casing 41 with an inlet tube 42 located near each end of the casing. The flange portion of the inlet pipe is connected to the lower side of one of the upper gate valves 36, that is, to the outlet side. casing 41
One end of the auger shaft 43 inside is supported by a journal 43a provided at one end of the casing.
A drive wheel or sprocket 44 is provided at the other end. Screw conveyor members 45a and 45b spirally spiraled in opposite directions are attached to the auger shaft 43, respectively. The electric motor 46 has a drive belt or chain 47, and the auger shaft 43 is driven in a direction to move the material from the ends of the casing 41 toward the central cross-section of the casing in FIG.

An outlet pipe 48 is provided in the central cross section of the casing 41.
is provided, the flange of the tube being connected to the flange of the bottom material control gate valve, indicated generally at 49. Control gate valve 49, like upper gate valve 36, has its gate actuation by means of any suitable pneumatic or other fluid cylinder 49a.

The compressed air conveyor 50 illustrated in FIG. 1 includes a line 51 connected to a source 52 of low pressure air.
The conduit 51 is located directly below the four pressure screw conveyors 40A and 40B and is connected to the four inlet pipes 5.
3. Each inlet pipe has one bottom gate 49
It is joined to the lower side, that is, the outlet side, with a flange.
Conduit 51 is of the conventional type normally used to transport powdered materials to storage silos.

Referring now to FIG. 2, air and valve system 60A includes pressure conduit 61 and high pressure air line 62 operatively connected to low pressure air source 52.
FIG. 2 depicts all valves of air and valve system 60A at 0.1 seconds after the start of the cycle. All valves in the system are closed except for vent valve 63, which is open. The vent valve is connected to the pressure screw conveyor inlet pipe 42 via conduit 64.
is communicated with the receiving hopper 10A.

System 60A also includes a pressurized diaphragm valve 65 and check valve 66 that control the flow of low pressure air from line 61 into pressure screw conveyor inlet pipe 42. A vent valve 67 is also provided for controlling the venting of air via a vent line 68 leading from the central region of the pressure screw conveyor casing 41 to the receiving hopper 10A. Vent valve 67 is opened and closed by one fluid cylinder 37 which actuates upper material control gate valve 36. In addition to the vent line 68 from the central portion of the pressure screw conveyor 40A, there is a vent valve line 69 from the surge hopper 30A connected to the vent line 68 above the vent valve 67. Therefore, the surge hopper 30A is always in communication with the receiving hopper 10A and is therefore maintained at a receiving hopper pressure of approximately atmospheric pressure.

Referring now to FIG. 6, the diagram shows the entire system in continuous operation. Pressure air conveyor 50, transfer screw conveyor means 20A
and 20B and pressure screw conveyors 40A and 40B are all operated continuously until the system is shut down. A section top gate valve 36 and bottom gate valve 49 are closed, A section vent valve 63 is open, A section vent valve 67 is closed, and A section pressure valve 65 is closed. The B section bottom gate valve 49 is open so that the pressure screw conveyor 40B is feeding powder material to the pressure air conveyor 50. B section upper gate valve 36 is closed;
B section vent valves 63 and 67 are closed;
And the pressure valve 65 of the B section is open.

At 12 seconds, the A section upper gate valve 36 and vent valve 67 both open and remain open until 56.4 seconds into the cycle, so material is fed to pressure screw conveyor 40A for 44.4 seconds. . The upper gate valve 36, the vent valve 63, and the vent valve 67 all close at 56.4 seconds, and the pressure valve 65 increases the pressure in the pressure screw casing of the pressure screw conveyor 40A to the same pressure as the pressure air conveyor 50. Open. 3.6 seconds are provided to generate pressure in the pressure screw casing,
The A section bottom gate valve 49 then opens at 60 seconds into the cycle so that the pressure screw conveyor 40A can feed material to the pressure air conveyor 50. This feeding action continues for 60 seconds, or until the 120 second mark of the cycle. At this time, the bottom gate valve 49 and the pressure valve 65 are closed, and the vent valve 6
3 is the casing 4 of the pressure screw conveyor 40A
1 to return to the receiving hopper pressure.

Meanwhile, at 60 seconds into the cycle, the bottom gate valve 49 of the -B section is closed and the pressure valve 65 of the -B section is also closed. Also, -
The ventilation valve 63 of the B section is open at the same time. At 72 seconds into the cycle, the -B section upper gate valve 36 and vent valve 67 open and material is fed from surge hopper 30B to pressure screw 40B from 72 seconds into the cycle to 116.4 seconds.
At that point, the upper gate valve 36, vent valve 63 and vent valve 67 of the B section are closed and the pressure valve 65 of that section is opened again. 120 cycles
At second, the bottom gate valve 49 of the B section opens again to supply material for 60 seconds.

The above times are not exact as all of the various valve actuations require at least 0.1 seconds.

As previously mentioned, the A and B sections of the set of acceptor hoppers are controlled in time to be one quarter cycle after the A and B sections of the set. The entire system therefore supplies material to the pneumatic conveyor 50 at a very stable rate.

It is, of course, to be understood that the systems disclosed herein are exemplary and that various modifications are possible depending on operating conditions. For example, the set could consist of only 12 receiving hoppers 10A, in which case the transfer screw would be short enough to require only two sections instead of three. is possible.

If the plant layout calls for six rows of receiving hoppers and three pressure screw conveyors, the pressure screws may be operated at low speed and feed pressure conveyor 50 in 180 second cycles;
The two pressure screws may be modified to feed material to the pressure conveyor at any time.

Although the system is shown and described as applied to a precipitator, it is equally applicable to any apparatus requiring the transfer of powdered material from a receiving hopper to a pressure conveyor.

Modifications can be easily thought of by those skilled in the art,
It is to be understood that the above detailed description is for ease of understanding and is not intended to limit the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a typical system implementing the invention. FIG. 2 is a diagram of the air and valve system for the A section surge hopper and pressure conveyor. FIG. 3 is an enlarged cross-sectional view taken substantially along line 3--3 of FIG. Fourth
The figure is a schematic cross-sectional view taken substantially along line 4--4 of FIG. 3. Figure 5 is substantially line 5 of Figure 3.
FIG. 5 is a schematic cross-sectional view taken along line -5. FIG. 6 is a cycle diagram for the system shown in FIG. 10A, 10B: Acceptance hopper, 20A, 20
B: Transfer screw conveyor means, 30A: Surge hopper, 36: Upper material control gate valve, 40A,
40B: Pressure screw conveyor, 41: Pressure screw conveyor casing, 42: Casing inlet, 43: Auger shaft, 45a, 45b: Screw conveyor member (auger), 48: Casing outlet,
49: Bottom material control gate valve, 50: Pressurized air conveyor means, 51: Conduit, 52: Low pressure air source.

Claims (1)

Claims: 1. A powder material transfer system for transferring powder material from a receiving hopper to a pressurized air conveyor line, comprising: a substantially airtight, substantially horizontal casing;
a powder material inlet tube attached to the top of the casing and communicating with the inside thereof; a powder material inlet tube attached to the bottom of the casing spaced apart from the powder material inlet tube and communicating with the inside of the casing and the pressurized air conveyor line; a powder material outlet pipe communicating through an upper part thereof, a mechanical conveyor disposed within said casing for transferring powder material through said casing from said powder material inlet pipe to said powder material outlet pipe; a mechanical conveyor means; a tube connected to the bottom of the receiving hopper and a powder material inlet tube of the pressure mechanical conveyor means and surrounding the powder material; a mechanical conveyor disposed within the tube surrounding the powder material; a transfer conveyor means; a first valve means in the powder material inlet pipe for controlling the movement of powder material into the casing; and a first valve means for controlling the movement of powder material from the casing to the pressurized air conveyor line. a second valve means in said powder material outlet pipe for cycling; a casing air pressure varying means for varying the air pressure in said casing between a low near atmospheric pressure and a higher line pressure; and successive cycles. and control means for filling the casing with powder material at the lower pressure and emptying the casing at the higher line pressure. 2. The powder material transfer system of claim 1, wherein a plurality of receiving hoppers are provided in a row, and the transfer conveyor means extends below the row of receiving hoppers and is connected to the bottom of all receiving hoppers. 3. Each receiving hopper in the receiving hopper row receives progressively less powder material from one end of the receiving hopper row to the other in the direction of the gas flow of the precipitator, until the receiving hopper receives the largest amount of powder material. 3. The powder material transfer system of claim 2, wherein the receiving hopper is the receiving hopper closest to the powder material inlet tube of the casing. 4. A second receiving hopper row comprising a plurality of receiving hoppers is provided adjacent to the first receiving hopper row,
A second transfer conveyor having a tube surrounding the powder material and a mechanical conveyor disposed within the tube extends below the second row of receiving hoppers and extends over the entire second row of receiving hoppers. connected to the bottom of the receiving hopper; furthermore, the casing of the piezo-mechanical conveyor means has a second powder material inlet pipe connected to said second transfer conveyor means; A powder material outlet pipe is disposed between the powder material inlet pipe of and the second powder material inlet pipe for said second receiving hopper row, and a mechanical conveyor within the casing transports the powder material between said two powder material inlets. 3. A powder material transfer system as claimed in claim 2, adapted to transfer powder material from a tube to said powder material outlet tube. 5 third and fourth hopper rows of a plurality of receiving hoppers are provided, third and fourth transfer conveyor means are arranged below the third and fourth hopper rows and all hopper rows of each hopper row are provided; said third and fourth transfer conveyor means each having a powder material enveloping tube and a mechanical conveyor disposed within said powder material enclosing tube, said third and fourth transfer conveyor means having a second airtight casing; a second pressure-mechanical conveyor means comprising: a second gas-tight casing having an inlet connected to said third and fourth transfer conveyor means for receiving powder material; A second mechanical conveyor is disposed in the casing for transferring the powder material to a pressurized air conveyor line, and a second mechanical conveyor of said second pressure mechanical conveyor
first and second valve means for controlling the movement of powder material into and out of the second hermetic casing, the air pressure within the second hermetic casing being reduced to near atmospheric pressure; casing air pressure variation means for varying the pressure between the pressure and a higher line pressure; periodically filling the second hermetic casing with powder material at the lower pressure and emptying the second hermetic casing at the higher line pressure in a second successive cycle offset by 5. A powder material transfer system according to claim 4, which operates in accordance with claim 4. 6. A system for transferring powdered material from a receiving hopper row consisting of a plurality of receiving hoppers to a pressurized air conveyor line, the system being below said receiving hopper row capable of receiving powdered material from all said hoppers at all times. an auger transfer conveyor means provided, and a substantially airtight and substantially horizontal casing;
a powder material inlet tube attached to the top of the casing and connected to the inside of the casing and one end of the auger transfer conveyor means, a powder material inlet tube provided at the bottom of the casing spaced from the powder material inlet tube and connected to the inside of the casing; a powder material outlet tube in communication and through an upper portion thereof to the pressurized air conveyor line, within the casing for transferring the powder material from the powder material inlet tube to the powder material outlet tube through the casing; pressure auger conveyor means having a continuously operating auger conveyor located in the casing; first valve means in the powder material inlet pipe for controlling the movement of the powder material into the casing; and a second valve means in said powder material outlet pipe for controlling the movement of powder material into an air conveyor line; and controlling the air pressure in said casing between a low near atmospheric pressure and a higher line pressure. casing air pressure varying means for varying the pressure at said pressure auger conveyor means, a first valve means first opening and a second valve means simultaneously closing to transport powder material at said low pressure from said auger transfer conveyor means to said pressure auger conveyor means. casing until said casing is substantially full, then said first valve means closes and the pressure within said casing increases to said higher line pressure, and then said second valve means closes and the pressure within said casing increases to said higher line pressure; a continuous cycle in which means are opened to allow an auger conveyor within said casing to empty said casing, and at the same time cause an auger transfer conveyor means to transfer powder material towards a powder material inlet pipe; and control means for producing a powder material transfer system. 7. A pressure-mechanical conveyor device for a powder material transfer system for transferring powder material from a receiving hopper to a pressurized air conveyor line, comprising: a substantially gas-tight casing; first and second powder material inlet tubes arranged at the bottom of the casing and adapted to be attached to the powder material transfer conveyor for receiving powder material from the powder material transfer conveyor; a powder material outlet tube located therebetween and adapted to be attached to the pressurized air conveyor line for delivering powder material to the pressurized air conveyor line; a mechanical conveyor disposed within the casing for transferring the powdered material to the outlet pipe; and a mechanical conveyor disposed within said casing for varying the internal pressure of the casing between a low pressure close to atmospheric pressure and a higher line pressure. and vent valve means.