JPH0213193B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a three-way valve, and particularly to a three-way valve used in a bottom-blowing converter, etc., to control the flow when gas mixed with solid powder is blown below the surface of molten metal. This invention relates to a three-way valve suitable for switching roads.

[Prior Art] As shown in German Patent No. 2838983 or Japanese Unexamined Patent Publication No. 57-29521, etc., in a bottom blowing converter,
A large amount of scrap is used, and a mixture of, for example, coal powder and methane gas is blown through several bottom tuyeres, and at the same time oxygen gas is blown through the remaining tuyeres to melt the scrap, and then the scrap is installed in the gas passage. A method has been proposed in which the molten metal in the furnace is smelted by switching the flow path of the switching valve, and continuing to blow oxygen gas containing quicklime powder through the tuyere, which had previously been blown with methane gas containing coal powder. There is.

Furthermore, Japanese Patent Laid-Open No. 56-33415 discloses an example of the structure of a switching valve. The outline is shown in Figure 1. Fine particle fuel with carbon suspended in carrier gas is introduced from the hole at the bottom of Figure 1, oxygen is introduced from the pipe at the top right of Figure 1, and these are fed into the molten iron bath (not shown) from the tuyere at the top of Figure 1. selectively sent. In the figure, 2 is a movable valve body, 4 is a seal, 6 is a valve housing, and 8 is a bellows.
When the pressure of oxygen introduced from the pipe in the upper right corner of the figure does not reach a predetermined value, the state shown is as shown, and fine fuel particles are introduced from the lower hole and fed into the molten iron bath from the upper tuyere. . On the other hand, when the oxygen pressure reaches a predetermined value, the valve body 2 moves in the direction of extending the bellows 8, blocking the fine particle fuel inlet and sending oxygen into the molten iron bath from the upper tuyere. .

[Problems to be Solved by the Invention] However, in this switching valve, when the movable valve body 2 and the seal 4 are closed, there is a risk that powder in the fine fuel particles may be caught. Furthermore, when used for a long time, the sealing performance deteriorates, and there is a possibility that reliable switching between the two types of powder gases becomes impossible.
Furthermore, in the case of two types of powder-containing gases that need to be avoided when switching the valve, such as methane gas containing lime powder and oxygen gas containing quicklime powder, the two types of powder-containing gases must be mixed inside the switching valve. There is a risk of mixing. On the other hand, when the two types of powder-containing gases are mixed, the lime in the gas may burn and the switching valve may overheat. If the seal 4 is deformed or burnt out due to this overheating, it becomes impossible to seal, which is extremely dangerous. In addition, the bellows 8 is abraded by the blown powder and holes are formed.
This may result in a mixture of different types of powder-containing gases, which may cause an explosion.

An object of the present invention is to provide a three-way valve that reliably prevents mixing of two types of powder-containing gases and prevents the gas pressure on the tuyere side from decreasing when switching the flow paths.

Another object of the present invention is to prevent particulate matter carried by the gas from getting caught in the gap between the valve body and the valve housing, and to have excellent durability and maintain sufficient airtightness over a long period of time. The purpose is to provide a three-way valve.

[Means for Solving the Problems] In order to achieve the above object, the present invention arranges a valve body having a main passage in a valve housing having two inlets, and rotates the valve body by a rotation drive device. In a three-way valve in which the main passage faces one of the inflow ports to switch the flow path, when the valve body is in a rotational position in the middle of switching, the main passage and a fluid supply source outside the three-way valve face each other. The present invention proposes a three-way valve in which the valve body and the valve housing are each provided with a purge fluid supply passage that communicates with the valve body and the valve housing.

Specifically, the valve body rotation drive device includes a cylinder device including a piston driven by fluid from a fluid supply source, and means for converting linear motion of the piston into rotational motion of a shaft of the valve body. Contains.

In order to achieve the other objects mentioned above, the present invention also provides a valve body having a main passage arranged in a valve housing having two inlets, the valve body being rotated by a rotary drive device, and a valve body having a main passage being rotated by a rotation drive device. In a three-way valve that switches the flow path by facing either one of the inflow ports, a purge that faces the main passage and communicates with a fluid supply source outside the three-way valve when the valve body is in a rotational position in the middle of switching. A three-way valve is proposed in which fluid supply passages are provided in the valve body and the valve housing, respectively, and a pressurized fluid supply passage is provided in the valve housing that communicates the gap between the valve body and the valve housing with a fluid supply source. It is something.

The pressurized fluid supply passage may be a passage branched from a purge fluid supply passage within the valve housing.

[Operation] When switching the flow path, the three-way valve of the present invention introduces purge fluid into the main passage inside the valve body, replaces the fluid that had been flowing inside the valve body with the purge fluid, and then introduces the fluid to be switched. It is designed to do so. Therefore, when switching the flow paths, mixing of the two types of powder-containing gases is reliably prevented. Also,
Even when switching the flow path, the gas pressure on the tuyere side is maintained at a predetermined value or higher by the purge gas pressure, and there is no possibility that materials in the converter will flow back to the switching valve side.

In the present invention, the valve housing is further provided with a pressurized fluid supply passage that communicates the gap between the valve body and the valve housing with the fluid supply source, and the internal pressure of the gap is always higher than that of the flow path. A three-way valve that does not allow entrained powder particles to get caught in the gap between the valve body and the valve housing, has excellent durability, and can maintain sufficient airtightness over a long period of time can be obtained.

[Embodiment] Next, an embodiment of the three-way valve according to the present invention will be described with reference to FIGS. 2 to 8 of the drawings.

FIG. 2 is a longitudinal sectional view of an embodiment of the three-way valve according to the present invention. This three-way valve 10 is installed in the middle of a gas supply passage connected to the tuyere of a bottom-blowing converter.

In FIG. 2, the housing 12 includes a main housing 14 and a bolt 16 attached to the main housing 14.
A housing cap 18 is attached to the housing cap 18. 19 is an O-ring for sealing, and 20 is a valve body housing portion formed in the housing 12.
The main housing 14 includes a first inlet 22 and a second inlet 24 that communicate the valve body housing 20 with the outside, and can supply gas A and gas B, respectively. On the other hand, housing cap 1
8 is provided with an opening 26.

A ball-shaped valve body 28 is housed in the valve body storage portion 20 . The valve body 28 has a shaft 30 as a rotation shaft.
and 31, and is supported by the housing 12 by bearings 32 and 34. Valve body 28
A main passage 36 is provided inside the main passage 36, one end of which serves as an opening 38 on the side peripheral surface of the valve body 28, and the other end serves as an outlet 40 of the three-way valve 10. This outlet 40 communicates with a tuyere of a bottom blowing converter (not shown). A ring-shaped large-diameter seal member 42 is attached to a seal retainer 44 at the openings of the first inlet 22 and the second inlet 24 facing the valve body 28.
The valve body 28 is supported by the elastic member 46 and biased in a direction to press the valve body 28, thereby preventing gases A and B from flowing into a gap 80, which will be described later.

This valve body 28 is rotated by a drive device 48. The drive device 48 includes a cylinder 50, a piston 52 housed in the cylinder 50, and a piston 5.
2, a rack 56 fixed to the rod 54, and a spring 58 for causing the piston 52 to move back. On the other hand, a shaft 60 is connected to the valve body 28, and a pinion 62 that meshes with the rack 56 is attached to the tip of the shaft 60. Pressure P _A or P _B is transmitted to the cylinder 50 from the purge fluid supply line 64 via the pressure control valve 66 and the flow rate adjustment valve 68 to move the piston 52 . Note that the flow rate control valve 68 is provided to reduce pressure fluctuations within the cylinder 50 due to the flow of purge fluid during flow path switching, which will be described later. When a pressure P _B greater than that which overcomes the spring 58 is transmitted from the purge fluid supply line 64, the piston 52 moves forward in the right direction in the figure. Accordingly, Rack 5
6 moves to rotate the pinion 62, and the valve body 28
Rotate in the positive direction. Purge fluid supply line 6
When the pressure transmitted from the piston 4 to the cylinder 50 is a relatively small pressure P _A , the repulsive force stored in the spring 58 causes the piston 52 to move back to the left in the figure. In response to the leftward movement of the rack 56, the pinion 62 and the valve body 28 rotate in the opposite direction.

The main housing 14 and the valve body 28 are provided with purge fluid supply passages 70 and 72, respectively, which communicate the main passage 36 with the outside of the three-way valve 10. The opening 76 of the passage 72 on the body 28 side is the valve body 28
The main passages 36 of the main passages 70 and 72 are arranged so as to face each other and to be in communication with each other when the passages 70 and 72 are in the middle of switching the flow paths.

3 and 4 are enlarged views showing the area around the opening 76. FIG. Figure 3 is - of Figure 2.
FIG. 4 is a horizontal cross-sectional view of FIG. 2 as viewed in the negative direction. A purge fluid supply passage 70 provided in the main housing 14 is supplied with purge fluid from a purge fluid supply line 64 via a conduit 78 . In addition, the valve body 28 and the housing 12
A purge fluid supply passage 82 communicating with the gap 80 is provided in the main housing 14 so that purge fluid can be supplied to the gap 80 under pressure.

Note that the opening 74 of the passage 70 has the first inlet 2
Similarly to the second inlet port 2 and the second inlet port 24, a ring-shaped small-diameter seal member 84 is disposed supported by a retainer 86 and an elastic member 88 to prevent leakage of the purge fluid.

Now, Fig. 2 shows a high pressure P _B in the cylinder 50.
is applied, and the piston 52 is shown in its most pushed-in state. At this time, the main passage 36 is in communication with the second inlet 24, and the gas B is flowing from the main passage 36 toward the tuyere of the bottom blowing converter. From this state, the pressure in the purge fluid supply line 64 is reduced, and the pressure applied to the cylinder 50 is set to P _A . the result,
Due to the repulsive force of the spring 58, the piston 52
moves to the left in the figure, the valve body 28 rotates, and the main passage 36 comes to communicate with the first inlet 22. During the rotation of the valve body 28 for this flow path switching, the main passage 36 is connected to the first inlet 22 and the second inlet.
It is in a state where it is not communicating with any of the inflow ports 24. In this state, the purge fluid supply passages 70 and 72 communicate with each other, and high-pressure purge fluid is supplied from the purge fluid supply line 64 to the main passage 36.

FIG. 5 is a diagram illustrating the state of connection between the opening 74 side and the opening 76 when looking in the direction of the axis 31 of the valve body 28 from the opening 74 side. FIG. 5a shows a state in which the first inlet 22 is in communication with the main passage 36. When the valve body 28 rotates in the directions 101, 102, and 103 from this state, the area of communication between the openings 74 and 76 gradually increases, and the purge fluid begins to flow. Then, after reaching the maximum communication state of c, further arrow 10
4, 105, and the flow of the purge fluid ends. The valve body 28 is opposite to the arrows 201 and 20.
2, . . . , 205, the purge fluid is supplied to the main passage 36 through the passages 70 and 72 by an operation opposite to that described above.

Figures 6 and 7 show gases A and B and purge fluid (gas in this example) C during this switching.
FIG. 2 is a diagram showing changes in flow rate over time. As shown in FIG. 6, when the arrows 101 to 105 rotate, gas C is supplied to the main passage 36 while gas A is being switched to gas B, and gas A in the main passage 36 is replaced with gas C. After that, gas B is allowed to flow into the main passage 36, and mixing of gas A and gas B is completely prevented. Also, as shown in Fig. 7, arrow 2
01 to 205, gas C is supplied to the main passage 36 in the middle of switching from gas B to gas A, the main passage 36 is purged, and gas B and gas A are mixed. Completely prevented.

In addition, since the purge fluid is always supplied under pressure from the passage 82 to the gap 80 between the valve body 28 and the housing 12, gas A or gas B is prevented from flowing into the gap 80, and these gases are prevented from flowing into the gap 80. The particles contained in the gas are reliably prevented from entering the gap 80.

As mentioned above, when the piston 52 is returned to the left in FIG. 2, a smaller pressure P _A is transmitted to the cylinder 50 than when it is moved to the right. As can be seen, this pressure P _A is such that the pressure of the purge fluid introduced into the main passage 36 is sufficient to overcome the static pressure of the molten metal on the tuyere. Also, pressure P _B during forward movement and pressure P _A during backward movement
It is desirable to set the elastic constant of the spring 58 to such an extent that the difference between the two values does not become excessively large.

In the above embodiment, the valve body 28 is driven by a drive device 48 that is driven by introducing the pressure of the purge fluid.
However, the present invention is not limited to this. The valve body 28 may be rotated by, for example, a motor. Furthermore, although the above embodiment relates to an example in which the three-way valve 10 is employed in a bottom-blowing converter tuyere, it is clear that the present invention can be widely applied to three-way valves that avoid mixing of two types of fluids such as gases. It is.

[Effects of the Invention] According to the present invention, when switching the flow path, purge fluid is introduced into the valve body main passage, the fluid in the valve body main passage is replaced with the purge fluid, and then another fluid is introduced. Therefore, mixing of the two types of fluids is reliably prevented.

Furthermore, there is no fear of a drop in tuyere gas pressure during switching, and gas switching can be performed stably.

Further, in the three-way valve of the present invention, the pressure of the purge fluid is constantly transmitted to the gap between the valve body and the housing, thereby preventing particles and the like from flowing into this gap. Therefore, no particles or the like are caught between the valve body and the housing, and the valve body has excellent durability and can maintain sufficient airtightness for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a conventional three-way valve, FIG. 2 is a sectional view of an embodiment of a three-way valve according to the present invention, and FIG.
The figure is a cross-sectional view along the arrows of the embodiment in FIG. 2, FIG. 4 is a cross-sectional view along the arrows of the embodiment in FIG. 2, and FIGS.
is a diagram showing a change in the communication area between the openings 74 and 76,
6 and 7 are diagrams showing changes over time in the flow rates of gases A, B, and C, and FIG. 8 is a diagram showing changes over time in the control pressure when the valve body is rotated. DESCRIPTION OF SYMBOLS 10... Three-way valve, 12... Housing, 14... Main housing, 16... Bolt, 18... Housing cap, 20... Valve body storage part, 22... First inlet, 2
4...Second inlet, 26...Opening, 28...Valve body, 3
0, 31... Valve body shaft, 32, 34... Bearing, 3
6... Main passage, 38... Opening, 40... Opening (outlet),
42... Seal member, 44... Seal retainer, 46
...Elastic member, 48...Drive device, 50...Cylinder,
52... Piston, 54... Rod, 56... Rack,
58... Spring, 60... Shaft, 62... Pinion, 64... Purge fluid supply line, 66... Pressure control valve, 68... Flow rate adjustment valve, 70... Purge fluid passage, 72... Passage, 74, 76... Opening, 78... Pipe path, 80... gap, 82... passage, 84... seal, 8
6... Retainer, 88... Elastic member, 101-105
...forward rotation direction, 201-205...reverse rotation direction.

Claims (1)

[Scope of Claims] 1. A valve body having a main passage is arranged in a valve housing having two inlets, and the valve body is rotated by a rotational drive device, so that the main passage is connected to one of the inlets. In a three-way valve that switches a flow path by facing the valve body, when the valve body is in a rotational position in the middle of switching, a purge liquid supply passage that faces the main passage and communicates with a fluid supply source outside the three-way valve is connected to the valve. A three-way valve, characterized in that the valve body and the valve housing are respectively provided. 2. The three-way valve according to claim 1, wherein the rotational drive device for the valve body includes: a cylinder device including a piston driven by fluid from the fluid supply source; and means for converting the rotational movement of the body axis into rotational movement. 3. A valve body having a main passage is arranged in a valve housing having two inlets, and the valve body is rotated by a rotary drive device, so that the main passage is opposed to one of the inlets to form a flow path. In the three-way valve for switching, when the valve body is in a rotational position in the middle of switching, a purge fluid supply passage that faces the main passage and communicates with a fluid supply source outside the three-way valve is connected to the valve body and the valve housing. A three-way valve, wherein the valve housing is provided with a pressurized fluid supply passage that communicates a gap between the valve body and the valve housing with the fluid supply source. 4. The three-way valve according to claim 3, wherein the pressurized fluid supply passage is a passage branched from the purge fluid supply passage within the valve housing.