JPH0215449B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a powder supply method for supplying powder such as pulverized coal, cement, water treatment agent, etc. from one hopper to another hopper. A powder replenishment device that replenishes powder from a hopper whose interior is pressurized can be considered, but in this case,
If the air supply pipe that communicates with the pressure gas source is opened at the top of the hopper, pressure will be applied to the powder surface in the hopper when the hopper is pressurized, compressing the powder and making it adhere tightly. There is a problem in that when the powder is dropped by gravity from the powder discharge port provided at the lower end, the discharge condition becomes poor. This invention solves the aforementioned problems by placing the pneumatic pipe as close as possible to the powder outlet of the hopper, thereby compressing the powder when introducing pressurized gas to increase the pressure inside the hopper. The object of the present invention is to provide a powder supply method that prevents the powder from coming into close contact and allows smooth discharge of the powder. That is, the present invention includes a service hopper having an airtight structure, and a pollination hopper that is connected to a powder discharge port at the lower part of the service hopper via a joint having an on-off valve, so that the internal pressure of both hoppers is approximately equalized. In the powder supply method, the powder in the hopper is supplied to the pollination hopper while maintaining the powder in the pollination hopper. Connect the air supply pipe with the opening at the tip to the service hopper so that H≦3d, where the distance from the tip to the powder discharge port of the service hopper is H, and the diameter of this powder discharge port is d. Powder is supplied to the service hopper with the on-off valve of the pressure regulating pipe and the on-off valve between both hoppers closed and with the upper space open to the atmosphere, and then the service hopper is airtight. Then, the internal pressure of the service hopper and the pollination hopper is equalized by supplying pressurized gas from the air supply pipe, and then the on-off valve of the air supply pipe is closed, and the on-off valve of the pressure regulating pipe and the opening and closing between the two hoppers are open the valve,
This is a powder supply method characterized by supplying powder in a service hopper to a pollination hopper. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In the figure, 1 is a service hopper, and a powder supply port 2 provided at the upper end of this hopper 1 is connected to a joint 6 with on-off valves 4 and 5 provided above and below a flexible pipe 3 as a feeding means. It is connected to a certain storage hopper 7. This storage hopper 7 is fixed to a device frame (not shown). The powder discharge port 8 provided at the lower end of the service hopper 1 is provided at the upper end of a pollination hopper (indicated as a weighing hopper 9 in the following examples) located below the service hopper 1. Powder inlet 10 and joint 1
1. This joint 11 has on-off valves 13 and 14 located above and below the flexible pipe 12.
are provided for each. A rotary quantitative powder supply device 15 for pneumatically feeding powder is integrally connected to the lower part of the measuring hopper 9, and a powder delivery port 16 is provided at the lower end of the powder supply device 15. This powder delivery port 16 is connected to an ejector-type pneumatic mixer 19 installed below the powder supply device 15 by a powder delivery pipe 18 having a flexible pipe 17 in place. A powder pneumatic pipe 20 is connected to the discharge side. Further, the service hopper 1 and the weighing hopper 9 are respectively supported by weighing devices 21 and 22, such as load cells, which are fixed to a device frame (not shown). Pressure gas inlets 23, 24 and 25 of the service hopper 1, metering hopper 9 and powder supply device 15 are formed by openings at the ends of air supply pipes 29, 30 and 31 having on-off valves 26, 27 and 28, respectively, These air supply pipes 29, 30, 31 are connected to on-off valves 26, 27, 28 and both hoppers 1,
9. Flexible pipes 32, 33, and 34 are provided between the powder supply device 15, and the air supply pipe 2
9, 30, and 31 are in communication with the air supply pipe 35 to the mixer 19 and a pressure gas source such as the same blower (not shown). Also, weighing hopper 9
An on-off valve 3 is provided at the pressure gas outlet 36 provided at the top of the
A depressurizing pipe 39 having pipes 7 and 38 is connected, and the tip of this pipe 39 is open to the atmosphere. The opening/closing valves 37 and 38 of the pressure relief pipe 39 are connected to the upper end of the service hopper 1 through a communication pipe 40, forming a pressure regulating pipe that connects the upper spaces of the service hopper 1 and the weighing hopper 9. . Opening/closing valve 1 of the joint 11 provided between the two hoppers 1 and 9
One end of a purge pipe 41 having an on-off valve 42 is communicated with the portion other than the flexible pipe 12 between 3 and 14, and the other end of this pipe 38 is open to the atmosphere. The pressurized gas inlet 23 of the service hopper 1 is placed as close as possible to the powder outlet 8. That is, at least inside the service hopper 1, the air supply pipe 23 is inclined at an angle of 60° to 90° with respect to the horizontal plane, and a tip opening, that is, a pressurized gas inlet 23 is disposed directly above the powder discharge port 8. The distance to the powder discharge port 8 is H, and the distance to the powder discharge port 8 is
Letting the diameter of d be H≦3d. Next, the operation of the powder measuring device configured as described above will be explained. When the powder supply device 15 is driven with the powder being charged up to the upper limit in the metering hopper 9, gas such as air whose pressure has been adjusted to the required pressure is supplied from the pressure gas source to the air supply pipes 30, 31, 35 to the metering hopper 9, powder supply device 15 and pneumatic mixer 19. As a result, the powder in the weighing hopper 9 is cut out in predetermined amounts by the rotation of the rotor of the powder supply device 15 under the action of gravity and pressure gas, passes through the powder delivery pipe 18, and is mixed for pneumatic feeding. The powder is sent to the powder container 19, and since pressure gas is also sent thereto, the powder is mixed with this gas and supplied to the required equipment and devices through the powder pneumatic pipe 20. In this case, if the pressure in the service hopper 1 is lower than the pressure in the metering hopper 9, the on-off valve 3 of the pressure relief pipe 39
7. Opening/closing valve 1 of joint 11 between both hoppers 1 and 9
3, 14, Air supply pipe 29 of service hopper 1
The on-off valve 26 is closed to prevent the pressure in the metering hopper 9, the powder supply device 15, and the pneumatic mixer 19 from decreasing. Then, since the inside of the service hopper 1 is empty, powder is put into the service hopper 1 from the storage hopper 7 when the amount of powder in the weighing hopper 9 decreases a little. That is, the on-off valves 37, 13,
14 and 26 remain closed, and the on-off valves 38 and the on-off valves 4 and 5 of the joint 6 between the service hopper 1 and the storage hopper 7 are opened, and the powder is transferred from the storage hopper 7 into the service hopper 1 by gravity. let it fall.
In this case, the gas in the service hopper 1 is replaced by the powder falling into the service hopper 1 and released into the atmosphere through the communication pipe 40 and the on-off valve 38 of the depressurization pipe 39 through the atmosphere side portion. The feeding of the powder to the service hopper 1 is completed before the powder in the weighing hopper 9 reaches the lower limit, and the powder in the service hopper 1 reaches the upper limit. When the powder in the service hopper 1 reaches the upper limit, it is detected by a level meter (not shown), etc.
The on-off valves 38, 4, and 5 are closed, and the on-off valve 26 is opened.
As a result, pressurized gas is introduced into the service hopper 1 from the air supply pipe 29. In this case, the on-off valves 37, 13, and 14 remain closed. When the pressure in the service hopper 1 increases until it becomes equal to the pressure in the weighing hopper 9, the service hopper 1 and the weighing device 2 of the weighing hopper 9
1 and 22, the on-off valve 26 is closed, and this state is maintained until the powder in the weighing hopper 9 reaches the lower limit. The supply of powder from the metering hopper 9 to the pneumatic mixer 19 continues during the above-described feeding of the powder to the service hopper 1 and the pressure equalization operation between the service hopper 1 and the metering hopper 9. Weighing hopper 9
When the powder inside reaches the lower limit, it is detected by an appropriate means and the on-off valves 37, 13, 14 are opened. As a result, powder is replenished from the service hopper 1 to the weighing hopper 9 by gravity within a short time. In this case, the air in this hopper 9 is replaced with the powder supplied to the weighing hopper 9 and is led to the service hopper 1 via a part of the pressure relief pipe 39 and the communication pipe 40, so that both hoppers 1, The pressure inside 9 is kept equal. When all of the powder in the service hopper 1 is replenished to the weighing hopper 9 and the powder in this hopper 9 reaches its upper limit, this is detected and the on-off valve 3
7, 13, and 14, and repeat the above-described operation. When the on-off valve 26 is opened to introduce pressurized gas into the service hopper 1 from the air supply pipe 29, the air supply pipe 29 is placed near the powder discharge port 8 at the lower end of the service hopper 1. 23, the pressure of the pressurized gas is applied from the bottom to the top of the powder, and the powder is not compressed and brought into close contact with each other. Therefore, the on-off valves 13 and 14 are opened while maintaining the internal pressures of the service hopper 1 and the weighing hopper 9 evenly, and the service hopper 1 is opened.
When replenishing the powder from the service hopper 9 to the weighing hopper 9, the powder is smoothly dropped and discharged from the service hopper 1 by gravity. Here, when examining the powder discharge state in the service hopper 1 by changing the distance H from the tip of the air supply pipe 29, that is, the distance H from the pressure gas inlet 23 to the powder discharge port 8, the results shown in Table 1 are obtained. I got it.
In this experiment, the diameter d of the powder discharge port 8 was 250 mm.
The discharge status was investigated when H was set to 100, 200, 400, 600, 700, and 800 mm.

[Table] It is clear from this result that when the distance H exceeds 3d, the powder is compressed by the pressure air introduced.
Due to the close contact, an arch of powder is generated in the hopper, making it impossible to discharge the powder. However, if H≦3d, the compressed air passes through the powder bed and rises, loosening the compacted powder again and fluidizing it, which prevents the compaction and adhesion of the powder in the hopper. In particular, the range of 0.5d≦H≦2d is preferable for powder replenishment. Further, the above-mentioned operations are automatically controlled by sending a detection signal to a control panel, and using electrical means or compressed air in conjunction with the same based on commands from the control panel. Furthermore, in this embodiment, a means is provided in the weighing hopper to detect the abnormal lower limit of the powder and stop the entire device, and the weighing device of the weighing hopper adjusts the electric motor of the powder feeding device according to the pressure inside the weighing hopper. It is preferable to control the rotation speed and make the powder supply amount appropriate. Furthermore, the present invention can be widely applied to a powder replenishment device from a hopper that introduces pressurized gas into the hopper and has an airtight structure, but as in the embodiment,
There is a great advantage in applying this method to a device in which a hopper for replenishing powder and a hopper for replenishing powder are communicated with each other to replenish powder while maintaining an even pressure. As explained above, the powder replenishment device of the present invention has a powder supply port provided at the upper end and a powder discharge port provided at the lower end, and an on-off valve provided at the bottom of the discharge port to form an airtight hopper. The tip of the air pipe that communicates with the pressure gas source via the on-off valve is opened, and the distance from the tip of the air pipe to the powder discharge port of the hopper is H, and the powder discharge port is Since the diameter of the outlet is d, it is arranged so that H≦3d, so that when pressure gas is introduced from the air pipe into the hopper to increase the internal pressure, the powder is not compressed and brought into close contact. Therefore, there is an effect that the powder can be smoothly discharged from the discharge port.

[Brief explanation of drawings]

The figure is a configuration explanatory diagram showing an embodiment of the present invention. 1...Service hopper, 2...Powder inlet, 5...
On-off valve, 8... Powder discharge port, 13... On-off valve, 23...
Pressure gas inlet, 26...opening/closing valve, 29...air supply pipe.

Claims (1)

[Claims] 1. A service hopper with an airtight structure, and a pollination hopper connected to a powder discharge port at the lower part of the service hopper via a joint having an on-off valve, and maintains the internal pressure of both hoppers almost equally. In the powder supply method for supplying the powder in the hopper to the pollination hopper, the upper spaces of both hoppers are connected by a pressure regulating pipe via an on-off valve and communicated with a pressure gas source via an on-off valve. Arrange the air supply pipe with the opening at the tip in the service hopper so that H≦3d, where the distance from the tip to the powder discharge port of the service hopper is H, and the diameter of this powder discharge port is d. supplying the powder to the service hopper with the on-off valve of the pressure regulating pipe and the on-off valve between both hoppers closed and with the upper space open to the atmosphere, and then making the service hopper airtight, Pressure gas is sent from the air supply pipe to equalize the internal pressure between the service hopper and the pollination hopper, and then the on-off valve of the air supply pipe is closed, and the on-off valve of the pressure regulating pipe and the on-off valve between both hoppers are opened. , a powder supply method characterized by supplying powder in a service hopper to a pollination hopper.