SEAL VALVE FOR A PCI SYSTEM OF A BLAST FURNACE

Abstract

A valve for a PCI system of a blast furnace including a valve housing with an inlet opening, an outlet opening and a maintenance opening, a maintenance door that is adapted to close the maintenance opening in an operating position during operation of the valve and that is removable from the maintenance opening into a maintenance position, a valve member movably mounted to the maintenance door, wherein, when the maintenance door is in the operating position, the valve member is movable between a closed position for closing the valve and an open position, and, when the maintenance door is in the maintenance position, the valve member is accessible from outside the valve housing.

Claims

1. A seal valve of a pulverized coal injection, PCI, system of a blast furnace, comprising: a valve housing with an inlet opening, an outlet opening and a maintenance opening, a maintenance door that is adapted to close the maintenance opening in an operating position during operation of the seal valve and that is removable from the maintenance opening into a maintenance position, a valve member movably mounted to the maintenance door, wherein, when the maintenance door is in the operating position, the valve member is movable between a closed position for closing the seal valve and an open position, and, when the maintenance door is in the maintenance position, the valve member is accessible from outside the valve housing, wherein the maintenance door is pivotably mounted to the valve housing to be pivotable about a first pivot axis (B) for movement between the operating position and the maintenance position.

2. The seal valve according to claim 1, wherein the seal valve is adapted for connection to a PCI conveying hopper.

3. The seal valve according to claim 1, wherein in the maintenance position, the valve member is disposed outside the valve housing.

4. The seal valve according to claim 3, wherein the valve housing comprises a planar flange surrounding the maintenance opening and the maintenance door rests against the flange in the operating position.

5. The seal valve according to claim 1, wherein the valve member is pivotable, about a second pivot axis (C), between the closed position and the open position.

6. The seal valve according to claim 5, wherein the valve member is a disc-like valve flap.

7. The seal valve according to claim 6, wherein the first pivot axis (B) is perpendicular to the second pivot axis (C).

8. The seal valve according to claim 1, wherein the seal valve comprises a valve seat inside the valve housing, wherein in the closed position, the valve member sealingly engages the valve seat to close the seal valve, and in the open position, the valve member is removed from the valve seat.

9. The seal valve according to claim 8, wherein the valve seat is detachably connected to the valve housing.

10. The seal valve according to claim 9, wherein the valve seat is removable through the maintenance opening.

11. The seal valve according to claim 8, wherein a sealing element with double sealing system is provided between said valve seat and said valve member, said double sealing system comprising a metallic seal and a soft seal.

12. The seal valve according to claim 8, wherein said valve seat comprises a heating element.

13. The seal valve according to claim 1, wherein said seal valve is designed so that the valve member is spaced-apart from an inner surface of the valve housing when being moved between the open position and the closed position.

14. The seal valve according to claim 1, wherein a drive shaft for transmitting a drive force from a drive unit outside the valve housing to the valve member is guided through the maintenance door.

15. The seal valve according to claim 14, wherein during operation, the drive unit is mounted to the maintenance door and the connection between the maintenance door and the valve housing is designed so that the drive unit remains mounted to the maintenance door when the door is moved to the maintenance position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Preferred embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

[0032] FIG. 1 is a first perspective view of an inventive seal valve with a maintenance door in an operating position;

[0033] FIG. 2 is a second perspective view of the seal valve from FIG. 1;

[0034] FIG. 3 is a perspective view of the seal valve FIG. 1 with the maintenance door in a maintenance position;

[0035] FIG. 4 is a top view of the seal valve from FIG. 1;

[0036] FIG. 5 is a sectional view according to the line of V-V in FIG. 4;

[0037] FIG. 6 is a sectional view according to the line VI-VI in FIG. 4 with a valve member in a closed position;

[0038] FIG. 7 is a sectional view corresponding to FIG. 6 with the valve member in an open position; and

[0039] FIG. 8 is an enlarged view of the sealing element of the seal valve of FIG. 6.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0040] FIGS. 1-7 show an inventive seal valve 1 that can be connected to the outlet of a conveying hopper that is part of a PCI (pulverized coal injection) system of a blast furnace. The seal valve 1 comprises a valve housing 2, which can be made of one or several pieces of steel. The valve housing has an inlet opening 2.1 and an outlet opening 2.2, which are aligned along a central axis A and are symmetric with respect to the central axis A. As indicated in FIG. 6, the seal valve 1 can be connected to an inlet pipe 20 at the inlet opening 2.1 and to an outlet pipe 21 at the outlet opening 2.2. The inlet pipe 2.1 may be an outlet pipe of a PCI conveying hopper and the outlet pipe 21 may be a PCI charging line leading to the tuyeres.

[0041] The housing 2 comprises a planar flange 2.3 that is parallel to the central axis A. A maintenance door 3 is connected to the flange 2.3 by two hinges 4, which define a first pivot axis B. FIGS. 1 and 2 show the seal valve 1 with the maintenance door 3 in an operating position, in which it is disposed in tight contact with the flange 2.3. In order to provide a tight and pressure resistant connection, a plurality of bolts 5 connect the maintenance door 3 with the flange 2.3 by engaging a corresponding plurality of threaded bores 2.6. As can be seen e.g. in FIG. 3, a valve member or valve flap 9 is pivotably connected to the maintenance door 3 by an arm 10. Thus, the valve flap 9 can rotate about a second pivot axis C with respect to the maintenance door 3. The second pivot axis C is perpendicular to the first pivot axis B, which in turn is parallel to the central axis A. As can be seen in FIGS. 6 and 7, the extreme positions of the pivot movement are a closed position (shown in FIG. 6) in which the valve flap 9 sealingly engages a valve seat 8 that is connected to the valve housing 2 by bolts 13, and an open position (shown in FIG. 7). The valve flap 9 has a circular disc-like shape which corresponds to an annular cross-section of the valve seat 8. In order to improve the tightness of the connection between the valve flap 9 and the valve seat 8, and annular elastic sealing element 14 is integrated into the valve seat 8. Alternatively, the elastic sealing element may be integrated in the valve flap 9. It is understood that in the closed position of FIG. 6, no pulverized coal can enter the valve housing 2 through the inlet opening 2.1.

[0042] This changes when the valve flap 9 is moved into the open position shown in FIG. 7, in which the valve flap 9 is removed from the valve seat 8 by a rotation of approximately 90° about the second pivot axis C. The corresponding motion is indicated by the double arrow. It should be noted that during the movement and even when the valve flap 9 is in the open position, it is spaced-apart from an inner surface 2.5 of the valve housing 2. Therefore, it is extremely unlikely that the motion of the valve flap 9 could be blocked or hindered by coal particles inside the valve housing 2. While only the closed position and the (fully) open position are shown, it will be understood that one or several intermediate positions of the valve flap 9 are conceivable. The movement of the valve flap 9 is driven by a drive unit 15 that is arranged outside the valve housing 2 and is mounted to the maintenance door 3. The drive force is transferred from the drive unit 15 to the valve flap 9 by a drive shaft 11 that is guided through the maintenance door 3 and to which the arm 10 is connected.

[0043] FIGS. 1, 2 and 4-7 show the seal valve 1 with the maintenance door 3 in an operating position, i.e. the position of the maintenance door 3 during operation of the seal valve 1. FIG. 3 however shows the maintenance door 3 in a maintenance position. In order to move the maintenance door 3 into this position, operation of the seal valve 1 has to be stopped temporarily and the bolts 5 have to be loosened. Afterwards, the maintenance door can be removed from a maintenance opening 2.4 that is surrounded by the flange 2.3. As can be seen in FIG. 3, the maintenance opening 2.4 is also surrounded by another elastic sealing element 7, which improves the tightness of the connection between the maintenance door 3 and the valve housing 2. The maintenance opening 2.4 provides access to the inside of the valve housing 2. The maintenance door 3 is moved into the maintenance position by a pivot movement about the first pivot axis B. It should be noted that the drive unit 15 remains connected to the maintenance door 3, i.e. the combined weight of maintenance door 3 and the drive unit 15 is supported by the hinges 4. The fact that the drive unit 15 does not need to be dismantled greatly facilitates any maintenance operation, in particular a precautionary inspection.

[0044] Since the valve flap 9 is mounted to the maintenance door 3, it is moved outside of the valve housing 2 when the maintenance door 3 is pivoted into the maintenance position. Therefore, any inspection, maintenance, cleaning, repair or replacement of the valve flap 9 can easily be performed. Furthermore, the maintenance opening 2.4 provides easy access to the inside of the valve housing 2. Above all, the present seal valve allows for easily accessing an elastic sealing element 14 integrated into the valve seat 8, which is most likely to require replacement. Also, it is possible to access the bolts 13 that connect the valve seat 8 to the valve housing 2. By loosening these bolts 13, the valve seat 8 can be disconnected from the valve housing 2 and can afterwards be moved outside the valve housing 2 through the maintenance opening 2.4. This greatly facilitates repair or replacement of the valve seat 8 or the sealing element 14. Moreover, the inner surface 2.5 of the valve housing 2 can be inspected, cleaned or repaired by the access provided through the maintenance opening 2.4.

[0045] As can be seen more clearly from FIG. 8, the sealing element 14 can be provided in the form of a double sealing system, comprising a metallic seal 14.1 and a soft seal 14.2. The metallic seal 14.1 is formed by two metallic elements, one on each of the valve seat 8 and the valve flap 9. The soft seal 14.2 can be lodged in one of the metallic elements and be in contact with the other metallic elements when the valve flap 9 is in its closed position. A heating element 14.3 may further be arranged in the valve seat 8 to provide the valve seat with a heated surface to prevent any accretions on the seat surface.

[0046] All these operations do not require dismantling the seal valve 1 from the PCI system. Therefore, any shutdown time of the PCI system—or at least part of it—can be minimized. In particular precautionary inspection of any part of the seal valve 1 can be performed easily, which enables to detect any possible problems at an early stage.

[0047] As can be noticed from the drawings, the valve housing is formed as a shell that provides an inner volume or chamber. Referring to the orientation of FIG. 7, the housing 2 has a top portion, with the inlet opening 2.1 an door 3, and a funnel-shaped bottom portion. The top portion has a top wall with the inlet opening connecting with tubular later walls with the maintenance opening, the lateral walls converging in the lower portion to form the funnel shape. The valve seat 8 is removably mounted to the inner side of top wall. For ease of maintenance, seal valve is configured such that the lower seat 8 region, with sealing element 14, is at a level coinciding with the maintenance opening 2.4, and that the seat 8 can pass through the maintenance opening 2.4. Hence, when the maintenance door 3 is opened, the operator has a direct view on the seat 8 and can easily access it.