JPS61295925A - Device for cutting out powder body - Google Patents

Abstract

PURPOSE:To adjust the feeding quantity of a fluidized powder body rapidly and in a wide range by providing a variable valve at the outlet of a tank and momentarily measuring the variation in the whole weight of said tank and adjusting the opening angle of said variable valve. CONSTITUTION:A variable throttle valve 30 is provided at the outlet part of a tank 10 holding a powder body A, and the opening of the variable throttle valve 30 is adjusted by an actuator 31 which is operated by air pressure. The weight of the tank 10 including the powder body A is converted into a electric signal by means of a converter 34, and measured by a measuring part 35. The cut-out speed of the powder body is operated based on the output signal of the measuring part 35, by an arithmetic unit 36, whose output signal is inputted into an opening adjuster 32 to operate an actuator 31. Accordingly, a powder body of a high mixing ratio can be fed at a wide range of cut-out speeds and, further, the powder body can be smoothly transferred without causing a blocking phenomenon of a nozzle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, injecting powder such as a desulfurizing agent or dephosphorizing agent into a container holding molten metal such as molten iron or molten copper, or applying pressure The present invention relates to a powder cutting device that supplies powder into a container.

[Conventional technology and problems]

This type of powder cutting device uses a carrier gas to transport the powder, and performs desulfurization, dephosphorization, and other chemical reactions in molten metal quickly, homogeneously, and efficiently. In order to maintain the mixing ratio of powder and carrier gas (weight of powder cut, weight of carrier gas) at the desired ratio,
Generally, it is required to increase this ratio and to uniformly fluidize the powder and supply it continuously and stably.

Further, it is desirable that this powder supply device be able to quickly and widely adjust the amount of powder supplied in accordance with various phenomena that occur during the reaction process within the molten metal.

FIG. 2 shows a conventional powder supply device, and in this figure,
Powder A held in tank 10 is forced through supply passage 11 to blowing lance 12 and blown into molten metal B from this lance 12 .

A breathable member 14 is provided inside the bottom 13 of the tank 10, and a pressure chamber 15 formed between the bottom 13 and the breathable member 14 is supplied with gas from a gas supply source 17 via a gas passage 16. , gas is sent, thereby fluidizing the powder A. The fluidized powder passes through the fixed nozzle 18 due to the differential pressure between the upper part 22 of the tank 10 and the outlet side of the nozzle 18, as will be described later, and flows out into the supply passage 11 via the on-off valve 19. The powder in the supply passage 11 is transferred to the lance 1 by the gas pressure-fed from the supply source 17 through the gas passage 20.
Transferred to the 2nd side. On the other hand, the gas path a 2x connects the supply source 17 and the upper part 22 of the tank 10, and pressurizes the inside of this upper part 22.

The supply flow rate of powder to the lance 12 is controlled by the differential pressure before and after the nozzle 180.
It is controlled by the pressure difference between the pressure P2 at point M of No. 2 and the pressure P at point N in the supply passage 11. For this reason, the control unit 23 converts the pressure P at point N into an electric signal using the converter 24 and takes in the pressure P at point M.
2 is converted into an electric signal by the converter 25 and taken in. Based on these signals, the differential pressure ΔP (=pz - PI) is detected and the opening degree of the control valve 26 is adjusted. In addition, the gas passage 20
The opening degree of the carrier gas control valve 27 provided in the gas passage 2
The carrier gas control unit 28 controls the gas flow rate within 0 to a predetermined value.

In the conventional apparatus having such a configuration, the powder flow rate, that is, the cutting speed changes depending on the differential pressure ΔP, and has a relationship as shown in FIG. 3, for example. In addition, in the figure,
φ1. φ2. φ3 indicates the diameter of the nozzle 18, φ1>φ2
〉There is a relationship of φ3.

As can be understood from this figure, when the diameter of the nozzle 18 is small (φ3), the cutting speed does not change greatly even if the differential pressure changes greatly. It is necessary to change the diameter to a larger one. On the other hand, if the diameter of the nozzle 18 is made too large, the cutting speed will be greatly affected by the differential pressure, making it difficult to control with high precision. However, in the conventional device, the diameter of the nozzle 18 has a certain range, and the variable range of the powder cutting speed by adjusting the differential pressure is about 1:3.

As a powder supply device having a fixed nozzle for one day as described above, the one described in Japanese Patent Publication No. 7238/1983 is known.

Furthermore, West German Patent No. 1147756 and West German Patent No. 118
9453, Austrian Patent No. 253417,
A configuration is disclosed in which a variable nozzle is provided in place of the fixed nozzle. However, with these variable nozzles, when the valve body is slightly displaced from the fully closed position and the flow path area is small, powder tends to clog the flow path within this variable nozzle, making it difficult to provide a stable powder supply. In order to prevent such disadvantages, the mixing ratio of powder and gas must be reduced.

In view of the above points, the present invention is a powder supply device that increases the mixing ratio of powder and gas, widens the variable range of the powder cutting speed, and prevents the powder from clogging the nozzle. The purpose is to obtain.

[Means for solving problems]

The powder supply device according to the present invention includes a tank that holds powder and is provided at an outlet of the tank, sprays gas onto the powder to fluidize the powder, and discharges the fluidized powder. and a valve body provided on the downstream side of the fluidizing means and reciprocating in a direction substantially perpendicular to the cutting direction of the powder,
A variable throttle valve that changes the flow path area through which the fluidized powder passes, and a pressure control that applies a pressure difference between the upstream side and the downstream side of the variable throttle valve and can change this differential pressure. It is characterized by comprising means.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, and the same parts as those of the conventional device shown in FIG. 2 are designated by the same reference numerals. In FIG. 1, a variable throttle valve 30 is provided at the outlet of a tank 10 that holds powder A, and the flow path formed by this variable throttle valve 30 is substantially bent in the direction of movement. Variable throttle valve 30
An actuator 31 that adjusts the opening degree of the throttle valve 31 is disposed outside the tank 10 and on the side of the variable throttle valve 30. This actuator 31 is an air cylinder device having a structure in which a piston is moved by air pressure, and is supplied with high pressure air from an opening adjuster 32 to move the piston, thereby adjusting the opening of the variable throttle valve 30. .

The opening adjuster 32 drives the actuator 31 according to the speed at which the powder A is taken out from the tank 10. In order to obtain this cutting speed, powder A is placed on the side of the tank 10.
A weighing device 33 is provided to measure the weight of the tank 10 including the weight of the tank 10. The weighing device 33 includes a converter 34 that converts the weight of the tank 10 into an electrical signal, and a weighing section 35 that measures the ever-changing weight of the tank 10 from the output signal of the converter 34. The output signal of the measuring unit 35 is differentiated with respect to time in the calculator 3G to calculate the cutting speed of the powder, and the output signal of the calculator 36 indicating the magnitude of this cutting speed is input to the opening degree regulator 32. . Thus, the opening adjuster 32 drives the actuator 31 to change the opening of the variable throttle valve 30.

The other configurations in FIG. 1 are the same as those in FIG. 2, and their explanation will be omitted.

4 and 5 show a preferred construction of variable throttle valve 30. FIG. Inside the annular body 41 fixed to the outlet portion of the tank 10, there is a first annular member 4 that narrows downward.
2 and a second annular member 43 that extends downward are fitted. Therefore, the first and second yJ-shaped members 42, 4
No. 3 has the smallest flow path area at these joint parts, and the hole 44 formed in this joint part has an oval shape (FIG. 4). A slide plate 45 that changes the opening degree of the hole 44 is reciprocated in the left-right direction in the figure by an actuator 31, and has a semicircular notch 46 formed at its tip. Accordingly, the opening area of the hole 44, that is, the flow path area changes with the displacement of the slide plate 45, and in this embodiment, the notch 46 is formed so that the flow path has a circular shape when the flow path area is the minimum.

The base 47 of the slide plate 45 protrudes into the casing 48, and the connecting member 49 is inserted into the casing 48.
The piston rod 50 of the actuator 31 is connected to the piston rod 50 of the actuator 31 via. The actuator 31 has inlet ports 51 and 52
High-pressure air is introduced from one side, thereby moving the piston rod 50 forward and backward to displace the slide plate 45. Note that the sensor 53 is for detecting the amount of displacement of the piston rod 50 to detect the opening degree of the variable throttle valve 30.

This embodiment operates as follows.

The differential pressure between a point M in the tank upper part 22 and a point N in the supply passage 11 is adjusted, and the opening degree of the variable throttle valve 30 is changed to set the powder cutting speed to a predetermined value. For example, when keeping the powder cutting speed constant, the differential pressure is fixed at a constant value, and the calculator 36
The opening degree of the variable throttle valve 30 is finely adjusted via the opening degree adjuster 32. In particular, when the opening degree of the variable throttle valve 30 is large, the cutting speed is susceptible to changes in differential pressure as explained in FIG. It can be done. On the other hand, when changing the cutting speed of the powder continuously, it is sufficient to change the differential pressure and the opening degree of the variable throttle valve 300. That is, in conventional devices that use a fixed nozzle, if the powder cutting speed is to be changed significantly, the fixed nozzle must be replaced, but according to this embodiment, the opening degree of the variable throttle valve 30 can be changed. It is easy to operate.

Tables 1 and 2 below show a comparison between the performance of the example device and the performance of the conventional device when specific powder is blown into molten iron under specific conditions using N2 gas.

Margin table below 1 Powder: Mill scale powder □□□ Degree: 150 mesh
under 100%) Table 2 Powder: Carbide desulfurization IJJ (a degree: 150 x
sh under 100%) As understood from the above tables, according to this example, it is possible to supply powder with a high concentration of about 1800, and the cutting speed is about 7.
It can be changed by a factor of two. However, in this example, if the differential pressure is varied within a range of 3 times, the cutting speed will be increased by approximately 20%.
It can be changed by a factor of two.

FIG. 6 shows the opening degree, that is, the opening area S of the hole 44 with respect to changes in the slide plate 45 when the hole 44 of the variable throttle valve 30 is oval, and FIG. 7 shows the opening area S of the variable throttle valve 30.
Slide plate 4 when hole 44 of 0 is circular
5 shows the opening degree of the hole 44, that is, the opening area S with respect to the displacement of 5. Both notches 46 are semicircular, and in the case of FIG. 6, the opening degree is O when the displacement of the slide plate 45 is 00, and in the case of FIG. 7, the opening degree is O when the displacement of the slide plate 45 is 0.
When , the opening degree is not 0. As can be understood from these figures, the hole 4 is formed by the slide plate 45 having the notch 46.
When changing the opening degree of slide plate 4, the opening degree is
It increases approximately in proportion to the displacement of 5. Further, when the hole 44 has a circular shape, the opening degree does not change much when the displacement of the slide plate 45 is around the minimum and maximum values.

Therefore, when the hole 44 is opened and closed by the slide plate 45 having the notch 46, the opening area S is relatively large (1, and the shape of the opening is a narrow slit) even when the displacement of the slide plate 45 is small. Rather, it is wide with a bulge in the center, so the powder passes smoothly through this opening.

FIG. 8 (al, (bl is the hole 44 of the variable throttle valve 30)
This is an example in which the left side edge 44a is formed not in an arc shape but in a triangular shape, that is, a straight portion is formed in this edge 44a. On the other hand, the slide plate 45 has a
Triangular notch 46 pointing in the opposite direction to the edge 4.43
The hole 44 is completely closed at the most advanced position. However, the slide plate 45
When is displaced to the right in the figure, as shown in Figure 8(b), the opening is 0 until the first displacement A, but increases in a quadratic curve until the next displacement A2. , then increases linearly to full throttle.

According to the embodiments described above, powder having a high mixing ratio can be supplied at a wide range of cutting speeds, and moreover, the powder is always smoothly transferred without causing any clogging phenomenon in the nozzle. In addition, control of sudden changes in cutting speed, which was possible only in mechanical cutting devices such as screw feeders, is also possible in nozzle type cutting devices (powder feeding devices). Furthermore, this embodiment has a simpler structure than a mechanical cutting device and has fewer worn parts, so maintenance and inspection are not required over a long period of time, and parts can be easily replaced. In the case of the above embodiment, even if the cutting speed is low, cutting is not performed intermittently but continuously, and as a result, pulsation in the supply passage 11 can be prevented.

Further, according to the above embodiment, it is easy to store a cutting speed pattern in a process computer or the like in advance and control the cutting speed in accordance with the pattern. Furthermore, since the actuator 31 is located outside the tank 10, maintenance and inspection of the actuator 31 is easy.

Note that as the actuator 31, a hydraulic cylinder or a motor may be used instead of the air cylinder.

Further, in place of the notch 46, even if a hole is bored at the tip of the slide plate 45, the same effects as in each of the above embodiments can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the mixing ratio of powder and gas is increased, the variable range of the powder cutting speed is expanded,
Moreover, the effect that the powder is always smoothly supplied without causing any clogging phenomenon can be obtained.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a system diagram showing a conventional device, and FIG. 3 is a graph showing changes in powder cutting speed with respect to differential pressure between the upper part of the tank and the supply passage. Fig. 4 is a plan view showing the variable throttle valve, Fig. 5 is a sectional view showing the variable throttle valve, Fig. 6 is a graph showing an example of changes in the opening degree of the variable throttle valve with respect to the slide plate, and Fig. 7 is the slide. FIG. 8 is a graph showing another example of the change in the opening degree of the variable throttle valve with respect to the plate (al is a plan view showing another example of the slide plate and the hole; FIG.
b) is a graph showing the change in opening degree in the example of FIG. 8 (al). 10...tank, 13...bottom, 14...
- Breathable member, 15... Pressure chamber, 17... Gas supply source, 30... Variable throttle valve, 45... Slide plate. Figure 2 Figure 3 Figure M5 Displacement Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A tank that holds powder, and a tank that is provided at the outlet of this tank and that sprays gas onto the powder to fluidize the powder and discharge the fluidized powder. The area of the flow path through which the fluidized powder passes is changed by a fluidizing means and a valve body provided on the downstream side of the fluidizing means and reciprocating in a direction substantially perpendicular to the cutting direction of the powder. What is claimed is: 1. A powder cutting device comprising: a variable throttle valve that controls the flow of the variable throttle valve; and pressure control means that applies a differential pressure between the upstream side and the downstream side of the variable throttle valve and is capable of changing the differential pressure. 2. The variable throttle valve includes a fixed nozzle and a slide plate that reciprocates in a direction substantially perpendicular to the powder flow path to change the size of the flow path, and at the tip of the slide plate, The powder cutting device according to claim 1, characterized in that a notch or a hole is formed. 3. The powder cutting device according to claim 1, wherein the fixed nozzle has a circular or substantially oval cross section. 4. The powder cutting device according to claim 1, wherein the powder cutting direction in the variable throttle valve substantially coincides with the direction of gravity.