JP4545048B2 - Gate valve - Google Patents

Description

  The present invention relates to a gate valve installed in a transportation line that mainly transports a fluid containing particulate matter in a coal gasification plant that gasifies coal and uses it as fuel for a gas turbine or the like.

Conventionally, a coal gasification plant has been attracting attention as an effective use of abundant coal. Such a coal gasification plant has a transportation line for transporting a fluid containing particulate matter such as coal as a fuel of a gasification furnace and unburned matter generated in the gasification furnace between the component devices, A valve for shutting off and sealing the fluid is provided in terms of operational control and safety.
Such a valve that operates in the atmosphere under the granular material may impede the operation of the valve body due to the entry and accumulation of the granular material into the valve box, and the entry of the granular material into the valve box. Measures to prevent this are required.
Further, depending on the operating conditions on the plant side, the sealing performance under high temperature and high pressure and the durability in high frequency operation may be required at the same time.
In addition, since the fluid transportation line containing particles generally has a large valve diameter and it is not easy to remove the valve from the system, it is possible to easily replace parts in the installed state during valve inspection and maintenance. It is desirable to have a valve structure.

Conventionally, for example, a through-conduit gate valve disclosed in Patent Document 1 has been proposed as a valve for a granular material that prevents the granular material from entering the gap of the valve box and accumulating in the valve box. In the conventional through-conduit gate valve, a secondary seal is provided outside the primary seal that seals the valve box and the flow path to prevent entry of particles into the valve box.
Further, as a gate valve that reduces the wear of the seal due to the abrasive fluid, there is a slurry gate valve disclosed in Patent Document 2, for example.
This is provided with a duplex partition plate that opens sequentially, first shuts off the fluid with the upstream partition plate, and then operates the downstream partition plate to prevent damage to the downstream seal part when the partition plate is half open. .

Further, as a gate valve that can be adjusted from the outside without complicating the valve structure and without disassembling the valve, for example, there is a gate valve shown in Patent Document 3. FIG. 11 shows the structure of the gate valve 100 shown in Patent Document 3.
This is because the main valve seat piece 107 and the sub valve seat piece 109 sandwich the front and back of the valve element 105 having the opening 101 and the closing portion 103, and the main valve seat piece 107 and the sub valve seat piece 109 are respectively front and rear. A seal surrounding the flow path 111 is provided. The main valve seat piece 107 is advanced and retracted by a bolt 113, and the contact pressure is maintained by the wedge effect. And the gate valve 100 is opened and closed by the valve element 105 moving up and down.

Japanese Patent Laid-Open No. 5-141548 JP-A-5-196153 JP 54-142625 A

However, the one disclosed in Patent Document 1 has a complicated double seal structure and has a problem that durability is low such that the seal is easily damaged because the seal is disposed on the movable part.
Moreover, since the thing shown by patent document 2 cannot prevent the fluid approaching into the valve box in intermediate opening, when applying to the fluid containing a granular material, a granular material accumulates in a valve box, There is a problem that the operation of the gate valve is hindered.
In the case of the fluid shown in Patent Document 3, since fluid cannot enter the valve box at an intermediate opening similarly to Patent Document 2, in the case of fluid containing powder, the powder is deposited in the valve box. There is a problem that the operation of the gate valve 100 is hindered.
When the gate valve is used at a high temperature, the contact surface pressure to the valve element 105 by the main valve seat piece 107 is adjusted by tightening the bolt 113. A gap for absorbing the thermal expansion of the main body 115 cannot be accurately given to the seal portion. Further, when the tightening of the main valve seat piece 107 is loosened, there is a problem that even if the bolt 113 is loosened, the main valve seat piece 107 does not follow and the main valve seat piece 1070 and the valve element 105 cannot be fixed.
Further, a seal packing 117 is provided on the sliding surface of the valve element 105. The powder particles easily enter the seal packing 117, and the seal packing 117 is liable to be damaged by sliding the powder particles. There is a problem that it is difficult to maintain the sealing function.
Further, in the disassembling work in the inspection and maintenance of the valve, there is a problem that the cover 119 is removed, the main valve seat piece 107 is extracted, the upper flange 121 is further removed, and the valve element 105 and the sub valve seat piece 109 are taken out. There is a point.
In view of the above-mentioned conventional problems, the present invention prevents malfunction due to accumulation of powder particles in the valve box, has good sealing properties and high durability, has a simple structure, and is easy to check and maintain. It aims at providing the gate valve which can be performed.

The present invention employs the following means in order to solve the above problems.
That is, the gate valve according to the present invention is an inflow in which a flow path that forms a part of the transport line is formed in a gate valve installed in a transport line that transports a fluid containing granular materials in a coal gasification plant. And a valve box having a portion and a discharge portion, and provided between the inflow portion and the discharge portion so as to extend in an opening / closing direction perpendicular to the axial direction of the flow path and to be movable in the opening / closing direction. A valve body, a wedge plate provided extending between the valve body and the inflow portion in the opening / closing direction, and a valve plate extending between the valve body and the discharge portion extend in the opening / closing direction. And a guide member that engages with the valve body and moves the valve body in the opening and closing direction, and the valve body is substantially orthogonal to the flow path and substantially parallel to each other. A first sliding surface on the inflow portion side and a second sliding surface on the discharge portion side are provided, and the opening / closing direction A valve body passage hole penetrating so as to constitute a part of the flow path is provided on one side of the intermediate position, and the wedge plate has a first surface in contact with the first sliding surface on the valve body side. Three sliding surfaces and an inclined support surface whose height gradually decreases toward the other side from the substantially intermediate position in the opening and closing direction on the inflow portion side, and the third sliding surface from the inclined support surface A wedge plate channel hole that penetrates toward the surface and forms a part of the channel, and the third sliding surface has a length that is at least the diameter of the valve body channel hole on one side in the opening and closing direction. The guide plate is provided with a fourth sliding surface in surface contact with the second sliding surface on the valve body side, and penetrated so as to constitute a part of the flow path. The guide plate channel hole has the fourth sliding surface on one side in the opening / closing direction with a length that is at least the diameter of the valve body channel hole. And a wedge plate concave ring provided at the inner end of the inflow portion so as to face the inclined support surface and surrounding the wedge plate channel hole of the inclined support surface. A first seal member having elasticity is mounted between the groove and the inclined surface, and a second seal member having elasticity is provided so as to surround the flow path between the guide plate and the discharge portion. A first urging means capable of urging the wedge plate to the other side in the opening / closing direction, and being disposed on the other side in the opening / closing direction of the first urging means, opening and closing the wedge plate. A second urging means capable of urging to one side of the direction, and the first seal member and the second seal member include a spiral gasket having a plurality of elasticity in the flow path axial direction, and characterized by being constituted by a metallic sealing plate through which it is so between the spiral gasket To do.

According to the present invention, a fluid flow path is formed by the flow paths of the inflow and discharge sections, the wedge plate flow path holes, and the guide plate flow path holes. Then, the valve body is slid by the moving means, and the valve body passage hole is formed so as to penetrate if the valve body passage hole overlaps the wedge plate passage hole of the wedge plate and the guide plate passage hole of the guide plate, The gate valve will be opened. Further, when the valve body is slid along the wedge plate and the guide plate to one side in the opening / closing direction by the moving means from this state, the valve body channel hole moves to one side, and the wedge plate The overlap of the flow path hole and the guide plate with the guide plate flow path hole gradually decreases, and finally does not overlap. That is, the gate valve is closed.
At this time, the flow path formed by the inflow portion and the wedge plate flow path hole of the wedge plate is sealed by the first seal member, and the flow path formed by the discharge portion and the guide plate flow path hole of the guide plate Is sealed by a second seal member.

The wedge plate has a third sliding surface at least on the one side in the opening / closing direction of the wedge plate channel hole with a length equal to or longer than the diameter of the valve body channel hole, and the guide plate has a guide plate channel hole. Since the fourth sliding surface exists at least on the one side in the opening / closing direction with a length equal to or larger than the diameter of the valve body passage hole, the valve body passage hole and the third sliding surface It is covered by the four sliding surfaces. That is, the opening surface of the valve body passage hole is covered and sealed by the third sliding surface and the fourth sliding surface at any point in the opening / closing operation of the gate valve.
On the other hand, the valve body passage hole is provided on one side of the intermediate position in the opening / closing direction of the valve body, so that the first slide longer than the diameter of the valve body passage hole is provided on the other side of the valve body passage hole. A moving surface and a second sliding surface are present. For this reason, the wedge plate channel hole is covered by the first sliding surface of the valve element and the guide plate channel hole is covered by the second sliding surface of the valve element until the valve element slides to one side and the gate valve closes. It will be broken and sealed.
As described above, since the gap between the flow path and the inside of the valve box is sealed at any opening degree, the fluid containing the granular material transported through the flow path is prevented from entering and depositing inside the valve box. be able to.
Further, since the valve element, which is a movable part, and the wedge plate and the guide plate are sealed by surface contact, the durability is high and the sealing efficiency can be improved.

Further, the first seal member and the second seal member are constituted by a spiral gasket having a plurality of elasticity in the flow path axis direction, and a metal seal plate interposed between the spiral gaskets. Therefore, the thermal expansion of the valve box is dispersed and absorbed by the plurality of spiral gaskets. For this reason, since the thermal expansion applied to each spiral wound gasket is within the elastic limit, excessive contact surfaces on the first sliding surface, the second sliding surface, the third sliding surface, and the fourth sliding surface The application of pressure can be prevented, and the operation reliability can be remarkably improved.
  Further, even if the spiral gasket is deformed, the sealing plate can keep the airtightness.

According to the present invention, when the wedge plate is urged to the other side in the opening / closing direction by the first urging means, the inclined support surface of the wedge plate approaches the inclined surface of the inflow portion and the first seal member is compressed. The When the first seal member is compressed, the wedge plate is pressed against the valve body by the reaction force. Since this pressing force is transmitted from the valve plate to the guide plate and from the guide plate to the second seal member, the contact pressure of the first seal member and the second seal member and the contact between the valve body, the wedge plate and the guide plate The contact pressure can be increased. The increased state can be fixed by operating the second urging means to urge the wedge plate to the other side.
On the other hand, when the first seal member is loosened and the wedge plate is biased to one side in the opening and closing direction by the second seal member, the inclined support surface of the wedge plate is separated from the inclined surface of the inflow portion, and the first seal member is extended. The When the first seal member is extended, the pressing force of the first seal member is weakened, and the contact pressure between the first seal member and the second seal member and the contact pressure between the valve body, the wedge plate and the guide plate are reduced. Can do. The reduced state can be fixed by operating the first urging means to urge the wedge plate to one side.
Thus, by operating the first urging means and the second urging means and appropriately adjusting the position of the wedge plate, the contact pressure of the first seal member and the second seal member, the valve body and the wedge plate, The contact surface pressure with the guide plate can be adjusted and maintained.

  In the gate valve according to the present invention, the moving means is disposed on either one side or the other side of the valve body and is detachably engaged with the valve body, so that the movement of the valve box is performed. An opening that can be opened and closed is provided on the opposite side to the means in the opening and closing direction.

According to the present invention, by opening the opening, the sliding trace between the wedge plate and the guide plate is observed and inspected, and the degree of wear damage is also observed on the sliding surface including the valve body or other parts. Judgment can be made and whether or not inspection is necessary can be determined in advance. Also, check the state of the powder particles staying inside the valve box, and the necessity of adjusting and checking the contact pressure of the first seal member and the second seal member and the contact pressure of the valve body, wedge plate and guide plate Can be determined.
Further, by opening the opening and detaching the moving means from the valve body, the wedge plate and the guide plate can be taken out from the valve body. Therefore, maintenance such as inspection inside the valve box or replacement assembly of internal parts can be performed without removing the valve box from the pipe.

  In the gate valve according to the present invention, a sprayed layer is provided on the surfaces of the first sliding surface, the second sliding surface, the third sliding surface, and the fourth sliding surface. Features.

As described above, since the thermal spray layer is provided on the surfaces of the first sliding surface, the second sliding surface, the third sliding surface, and the fourth sliding surface, it can be used in a high temperature corrosive environment and in a powdery state. Even when sliding in a granular atmosphere, the sealing performance of these sliding surfaces can be maintained for a long time.
As the thermal sprayed layer, abrasion resistance, excellent material corrosion resistance and sliding mechanical properties are suitable, chrome carbide (Cr 3 _{C 2)} as an example.

  Further, in the gate valve according to the present invention, the flow path is formed in a substantially vertical direction with the discharge portion disposed on the lower side, and the other end portion of the guide plate has the guide plate flow path hole. The valve box is held at a position substantially below one end of the guide plate with a gap corresponding to the thermal expansion of the valve box between the guide plate and the guide plate. And a spring having a spring force for supporting the weight of the guide plate, the valve body and the wedge plate is provided between the holding portion and the guide plate.

According to the present invention, the other end of the guide plate is positioned to extend to the other side from the guide plate channel hole, so that the valve body having a center of gravity on the other side from the valve body channel hole is provided. Even when sliding, the valve body is always guided by the guide plate and slid stably.
Since the wedge plate and the guide plate are arranged so as to be biased to one side, the center of gravity of the wedge plate, the valve body and the guide plate is located on one side from the guide plate channel hole. For this reason, a downward moment always acts on one end of the guide plate in the sliding state of the valve body.
Since this downward moment is supported by a spring provided between the holding portion and the guide plate, the guide plate, the valve body and the wedge plate are always kept horizontal, so that the valve plate performs a stable operation. Can do.
In addition, since the holding portion is provided below the substantially end portion on one side of the guide plate with a gap corresponding to the thermal expansion of the valve box between the guide plate and the holding portion even if the valve box is thermally expanded. Will not abut against the guide plate and push up.

  Further, the gate valve according to the present invention is characterized in that a guide plate is detachably provided on the inner surface of the valve box facing the valve body with a minute gap.

In this way, the guide plate is provided with a minute gap on the inner surface of the valve box facing the valve body, so even if the valve body shakes due to the presence of a minute amount of powder or the like, It is possible to prevent a problem from occurring due to contact with the valve box simply by contact.
In addition, since the guide plate is detachably attached to the valve box, if wear caused by contact and sliding of the valve plate occurs, it can be handled by replacing only the guide plate, facilitating maintenance. It can be carried out.

According to the gate valve of the present invention, it is possible to prevent the fluid containing the particulates transported through the flow path from entering and depositing inside the valve box at any opening between the flow path and the inside of the valve box. Can do.
Further, since the valve element, which is a movable part, and the wedge plate and the guide plate are sealed by surface contact, the durability is high and the sealing efficiency can be improved.
Further, by operating the first urging means and the second urging means to appropriately adjust the position of the wedge plate, the contact pressure of the first seal member and the second seal member, the valve body, the wedge plate, and the guide plate The contact surface pressure can be adjusted and maintained.

Below, the gate valve 1 concerning one Embodiment of this invention is demonstrated using FIGS. 1-10. The gate valve 1 of this embodiment is used for a transportation line that transports high-temperature powder.
FIG. 1 is a front view showing a transverse section of the gate valve 1. FIG. 2 shows a plan view of the gate valve 1, and the lower half shows a cross section thereof.
The valve box 3 includes a substantially cylindrical valve box body 5, a one-side lid (opening) 7 that opens and closes one (A) side of the valve box body 5, and the other (B) side of the valve box body 5. And a lid 9 on the other side for opening and closing.
The valve box body 5 is installed such that its axial direction is horizontal. An inflow portion 13 having an inflow passage 11 and a discharge portion 17 having a discharge passage 15 are provided at a substantially intermediate position in the axial direction (opening / closing direction) 25 of the valve box body 5. The axial centers of the inflow channel 11 and the exhaust channel 15 are substantially the same and extend in the vertical direction (the axial direction of the channel) 27.
An inclined surface 19 opened on one side is formed at the inner end of the inflow portion 13.

Between the inflow portion 13 and the discharge portion 17, a wedge plate 21, a valve body 23, and a guide plate 25 are respectively provided extending horizontally in the axial direction 25 of the valve box body 5 from the inflow portion 13 side. Yes.
The valve body 23 is a plate member having a substantially rectangular shape with one side protruding in a semicircular shape, and has an upper sliding surface (first sliding surface) 27 and a lower sliding surface (second sliding surface) 29 on the top. And are provided. Further, the valve body 23 is provided with a valve body passage hole 31 penetrating from the upper sliding surface 27 to the lower sliding surface 29 on one side of the intermediate position in the opening / closing direction 25.

  The wedge plate 21 is a substantially oval plate member, and a wedge plate sliding surface (third sliding surface) 33 that is in surface contact with the upper sliding surface 27 is provided on the valve body 23 side. The wedge plate 21 is provided with an inclined support surface 35 that protrudes in a cylindrical shape from the substantially intermediate position in the opening / closing direction 25 on the inflow portion 13 side to the other side and whose upper end gradually decreases toward the other side. A wedge plate channel hole 37 penetrating from the inclined support surface 35 toward the wedge plate sliding surface 33 is provided. The inclined support surface 35 is provided with a concave annular groove 39 surrounding the periphery of the wedge plate channel hole 37. Further, the wedge plate sliding surface 33 exists at least as long as the diameter of the valve body passage hole 31 from one end portion of the wedge plate 21 to one end portion of the wedge plate passage hole 37. It is configured.

The guide plate 25 is a plate member having a substantially rectangular shape with one side protruding in a semicircular shape, and a guide plate sliding surface (fourth sliding surface) 41 that is in surface contact with the lower sliding surface 29 on the valve body 23 side. Is provided.
The guide plate 25 is provided with a guide plate channel hole 43 penetrating in the vertical direction 27 at a position on the other side from a substantially intermediate position in the opening / closing direction 25. The guide plate sliding surface 41 is configured to exist at least as long as the diameter of the valve body channel hole 31 from the one side end of the guide plate 25 to the one side end of the guide plate channel hole 43. ing. Further, the other end portion of the guide plate 25 is located at a center of gravity where the guide plate 25, the valve body 23 and the wedge plate 21 are integrated in a state where the valve body passage hole 31 overlaps the guide plate passage hole 43. Is also located on the other side.
On the discharge portion 17 side of the guide plate 25, a guide plate concave annular groove 45 surrounding the periphery of the guide plate channel hole 43 is provided.
On the upper surface of the discharge part 17, a protrusion 47 (see FIG. 8) surrounding the periphery of the discharge flow path 15 is provided so as to fit with the guide plate concave annular groove 45.

Next, the sealing structure of the wedge plate 21 and the inflow portion 13 and the guide plate and the discharge portion 17 will be described with reference to FIGS.
An inflow portion seal gasket (first seal member) 57 is provided in the concave annular groove 37 of the wedge plate 21 so as to protrude from the inclined support surface 35 as shown in FIG. The inflow portion seal gasket 57 includes three spiral gaskets 59 and two seal plates 61.
As shown in FIG. 8, a discharge portion seal gasket 63 having the same structure as the inflow portion seal gasket 59 is provided between the guide plate concave annular groove 45 of the guide plate 25 and the protruding portion 47 of the discharge portion 17. Yes.
As shown in FIG. 9, the spiral wound gasket 59 is formed by arranging a plurality of metallic hoop materials 65 at intervals in a filler 63. The hoop material 65 is curved in a substantially square shape and is configured to allow elastic deformation in the vertical direction.
The seal plate 61 is made of metal and has a function of being installed in close contact with the groove walls of the concave annular groove 37 and the guide plate concave annular groove 45 to maintain airtightness.

In the spiral wound gasket 59, when the hoop material 65 is used in an elastic deformation region, the hoop material 65 behaves like a spring and can be restored. Therefore, the amount of compression per spiral wound gasket 59 can be reduced. The number of gaskets is determined so as to be within the elastic deformation region of 65.
Further, since the reaction force of the inflow portion seal gasket 57 and the discharge portion seal gasket 63 becomes the contact pressure of the metal sliding surface between the valve body 23, the wedge plate 21 and the guide plate 25, the gasket reaction generated at the time of absorbing thermal expansion. If the contact pressure on the metal sliding surface becomes excessive due to an increase in force, the metal sliding surface may be damaged due to seizure or the like.
For this reason, by using a plurality of spiral wound gaskets 59 in an overlapping manner, an increase in the contact pressure of the metal sliding surface when absorbing thermal elongation is reduced. Therefore, the number of spiral gaskets 59 is determined in consideration of the critical contact pressure of the metal sliding surface.
The general crushing allowance of the spiral wound gasket 59 is 1.2 mm, but in the present embodiment, consideration is given to the restoring force and the reaction force increase of the inflow portion seal gasket 57 and the discharge portion seal gasket 63 due to thermal elongation. The crushing allowance is limited to 1/4 to 1/5 (0.24 mm to 0.3 mm).

A protrusion 49 is provided on the upper surface of one side of the wedge plate 21. An adjustment bolt (first urging means) 51 screwed to the valve box body 5 is provided on one side of the protrusion 49, and a bolt (second urging means) screwed to the valve box body 5 is provided on the other side. 53 is provided so that engagement is possible.
Further, the upper sliding surface 27 and the lower sliding surface 29 of the valve body 23, the wedge plate sliding surface 33 of the wedge plate 21, and the guide plate sliding surface 41 of the guide plate 25 are excellent in high temperature sliding characteristics. Chrome carbide (Cr ₃ C ₂ ) is thermally sprayed, which has characteristics such as very little attacking on the counterpart material, and also has wear resistance and corrosion resistance in a granular material atmosphere.
A guide plate 67 is detachably attached to the inner peripheral surface of the valve box body 5 with bolts 69 with a minute gap between the valve plate 23 and the valve plate 23 along the left and right surfaces. In addition, on both ends of the guide plate 67 in the opening and closing direction, flanges 71 that fit the valve box body 5 are provided. The sliding surface of the guide plate 67 is made of a material excellent in mechanical slidability and wear resistance, such as a cobalt-based alloy.

Next, the moving means 73 will be described. The moving means 73 is installed on the other side of the valve box 3. When a rotational driving force is applied to the rotating body by the operating device 77 or the handle, the screw rod 79 screwed to the rotating body moves in the opening / closing direction. The valve rod 75 attached to one end of the screw rod 79 moves in the opening / closing direction as the screw rod 79 moves.
At the other end portion of the valve body 23, an inverted T-shaped engagement groove 55 whose inner side is widened in a plan view is provided. On the other hand, a hanger portion 81 is provided at one end of the valve stem 75. The hanger portion 81 is a block having a cross section of an ellipse in cross section, the length of the short axis is smaller than the width D of the entrance portion of the engagement groove 55, and the length B of the long axis is the entrance portion of the engagement groove 55. It is set to be larger than the width D of the engagement groove 55 and smaller than the width A of the widened portion of the engagement groove 55. Accordingly, as shown in FIG. 6, when the long axis of the hanger portion 81 is engaged with the widened portion of the engaging portion 55, the valve plate 23 opens and closes as the valve stem 75 moves in the opening and closing direction. Move in direction 25. On the other hand, when the valve rod 75 is rotated by 90 ° from the state of FIG. 6, the short shaft of the hanger portion 81 is positioned in the engagement position relationship, so that the engagement groove 55 is not engaged.

Next, the holding unit 83 will be described with reference to FIG.
A pair of left and right holding portions 83 are provided below the substantially end portion on one side of the guide plate 25. The holding portion 83 is provided with a holding shaft 85 attached to the valve box body so as to be movable in the vertical direction. The upper portion of the holding shaft 85 is enlarged in diameter, and the lower portion of the enlarged diameter portion is configured to be supported by a holding shaft attachment plate 87 fixed to the lower portion of the guide plate.
A gap α corresponding to the thermal expansion of the valve box is provided between the upper end of the holding shaft 85 and the guide plate 25. A spring 89 is mounted between the holding shaft 85 and the guide plate 25 to balance the weight of the guide plate 25, the valve body 23, and the wedge plate 21.

The operation of the gate valve 1 according to this embodiment described above will be described.
First, adjustment of the seal contact surface pressure will be described.
When the protrusion 49 is biased to the other side in the opening / closing direction 25 by the adjusting bolt 51, the wedge plate 21 is biased in the same direction. As a result, the inclined support surface 35 of the wedge plate 21 approaches the inclined surface 19 of the inflow portion 13, so that the spiral gasket 59 of the seal gasket 57 is compressed. When the spiral gasket 59 is compressed, the wedge plate 21 is pressed against the valve body 23 by the reaction force. This pressing force is transmitted from the valve plate 23 to the guide plate 25 and from the guide plate 25 to the guide plate seal gasket 63, so that the wedge plate sliding surface 33 and the upper surface are interposed between the seal gasket 57 and the inclined surface 19. The contact pressure and the contact pressure between the sliding surface 27, between the lower sliding surface 29 and the guide plate sliding surface, and between the guide plate seal gasket 63 and the protrusion 47 can be increased. The wedge plate 21 can be fixed in this increased state by urging the projection 49 to the other side by the bolt 53.

Conversely, when the adjustment bolt 51 is loosened and the projection 53 is urged to one side in the opening / closing direction 25 by the bolt 53, the inclined support surface 35 of the wedge plate 21 is separated from the inclined surface 19 of the inflow portion 13. The gasket 57 is extended. When the seal gasket 57 is extended, the reaction force of the seal gasket is weakened, and the contact pressure between the seal gasket 57 and the guide plate seal gasket 63 and the contact pressure between the valve body 23 and the wedge plate 21 and the guide plate 25 are reduced. Can do. The reduced state can be fixed by operating the adjustment bolt 51 to urge the protrusion 49 to one side.
As described above, the adjustment bolt 51 and the bolt 53 are operated to finely adjust the position of the wedge plate 21 in the opening / closing direction 25 as appropriate, so that the contact pressure of the seal gasket 57 and the guide plate seal gasket 63 and the valve body 23 and the wedge are adjusted. The contact pressure between the plate 21 and the guide plate 25 can be adjusted, and the state can be maintained.

Next, the opening / closing operation of the gate valve will be described with reference to FIGS.
3 shows a state where the gate valve 1 is fully opened, FIG. 4 shows a state where the gate valve 1 is at an intermediate opening, and FIG. 5 shows a state where the gate valve 1 is fully closed. .
In the gate valve 1, a fluid channel is formed by the inflow channel 11, the wedge plate channel hole 37, the guide plate channel hole 43, and the discharge channel 15. Then, when the valve body 23 is slid in the opening / closing direction 25 by the moving means 73 and the valve body passage hole 31 overlaps the wedge plate passage hole 37 of the wedge plate 21 and the guide plate passage hole 43 of the guide plate 25. A flow path penetrating in the vertical direction is formed, that is, the gate valve is opened.

FIG. 3 shows a state in which the valve body 23 has moved to the other side and the valve body flow passage hole 31 is substantially completely overlapped with the wedge plate flow passage hole 37 and the guide plate flow passage hole 43, that is, the gate valve 1 is fully opened. The state is shown.
When the valve body 23 is slid along the wedge plate sliding surface 33 of the wedge plate 21 and the guide plate sliding surface 41 of the guide plate 25 to the one side in the opening / closing direction by the moving means 73 from this state. Then, the valve body passage hole 31 moves to one side, and the overlap between the wedge plate passage hole 37 of the wedge plate 21 and the guide plate passage hole 43 of the guide plate 25 is gradually reduced (see FIG. 4). Do not overlap (see FIG. 5). That is, the gate valve is closed.
At this time, the channel formed by the inflow channel 11 and the wedge plate channel hole 37 of the wedge plate 21 is sealed by the seal gasket, and the discharge channel 15 and the guide plate channel hole 43 of the guide plate 25 The flow path formed by is sealed by a guide plate seal gasket 63.

The wedge plate 21 has a wedge plate sliding surface 33 on the one side in the opening and closing direction of the wedge plate passage hole 37 with a length at least as long as the diameter of the valve body passage hole 31, and the guide plate 25 has Since the guide plate sliding surface 41 is present on the one side in the opening / closing direction of the guide plate channel hole 43 at least as long as the diameter of the valve body channel hole 31, the valve body 21 slides from fully open to fully closed. During the movement, the valve body passage hole 31 is covered with the wedge plate sliding surface 33 and the guide plate sliding surface 41. That is, the opening surface of the valve body passage hole 31 is covered and sealed by the wedge plate sliding surface 33 and the guide plate sliding surface 41 at any time of the opening / closing operation of the gate valve 1.
On the other hand, since the valve body channel hole 31 is provided on one side of the valve body 23 in the opening / closing direction, the other side of the valve body channel hole 31 has a diameter larger than that of the valve body channel hole 31. A long upper sliding surface 27 and a lower sliding surface 29 are present. Therefore, the wedge plate channel hole 37 remains on the upper sliding surface 27 of the valve element 23 until the valve element 23 slides from the fully open state (see FIG. 3) to one side and the gate valve 1 is closed (see FIG. 5). Thus, the guide plate channel hole 43 is covered and sealed by the lower sliding surface 29 of the valve body 23.

In this way, since the gap between the fluid flow path and the internal space of the valve box 3 is sealed at any opening, the fluid containing the granular material transported through the flow path enters and accumulates inside the valve box 3. Can be prevented.
Further, since the valve body 23, which is a movable part, and the wedge plate 21 and the guide plate 25 are sealed by surface contact by the sliding surfaces, the durability is high and the sealing efficiency can be improved. .
Since the chrome carbide sprayed layer is provided on the surfaces of the upper sliding surface 27, the lower sliding surface 29, the wedge plate sliding surface 33 and the guide plate sliding surface 41, it is possible to generate powder in a high temperature corrosive environment. Even when sliding in a granular atmosphere, the sealing performance of these sliding surfaces can be maintained for a long time.

The wedge plate 21, the valve body 23 and the guide plate 25 are supported by the discharge portion 17 and the holding portion 83.
Since the center of gravity of the wedge plate 21 and the guide plate 25 is biased to one side, the center of gravity of the wedge plate 21, the valve body 23 and the guide plate 25 is from the guide plate channel hole 43 regardless of the position of the valve body 23. Located on one side. For this reason, a downward moment is acting on the end of one end of the guide plate 25 at all times.
The downward moment is supported by a spring 89 provided between the holding shaft 85 and the guide plate 25, so that the guide plate 25, the valve body 23 and the wedge plate 21 are always kept horizontal.
Further, since the other end portion of the guide plate extends from the guide plate channel hole to the other side, the valve body 23 having a center of gravity on the other side of the valve body channel hole 31 is on the other side. Even if it moves, the valve body 23 is guided by the guide plate 25.
Therefore, since the valve body 23 is supported by the guide plate 25 and is slid substantially horizontally, a stable operation can be performed.
The level of the guide plate 25 is adjusted by moving the holding shaft 85 up and down.
Further, since the holding shaft 85 is provided with a clearance α corresponding to the thermal expansion of the valve box between the holding plate 85 and the guide plate 25, the holding shaft 85 contacts the guide plate 25 even if the valve box 3 is thermally expanded. Will not push up.

Since the valve body 25 is connected to the valve rod 75 with a gap, for example, there is a possibility of meandering from side to side during operation. Further, the valve body 23 may be shaken by factors such as the presence of a minute amount of powder particles that have entered the sliding surface.
If the valve body 23 swings to the left and right during sliding, the valve body 23 slides while coming into contact with the guide plate 67, so that the valve body 23 does not come into contact with the valve box body 5 to cause a problem. Further, since the guide plate 67 is made of a material having excellent machine slidability, seizure, galling, etc. do not occur even when contact sliding occurs. Even when the valve body 23 comes into contact with the guide plate 67 and slides, the guide plate 67 is restricted from sliding by the flange 71.
In addition, since the guide plate 67 is detachably provided on the valve box body 5, when the valve body 23 comes into contact and slides and wears, it can be dealt with by replacing only the guide plate 67, Maintenance can be performed easily.
By providing the flange, it is possible to prevent the guide from loosening due to the load in the stroke direction.

Next, disassembly and inspection of the gate valve 1 will be described.
When inspecting the inside, first, the one-side lid 7 is removed. Thereby, the one side end is greatly opened. From this open part, the sliding traces of the wedge plate 21 and the guide plate 25 are observed and inspected, the degree of wear damage is also judged on the sliding surface including the valve body 23 or other parts, and the necessity of inspection is required. Can be determined in advance.
Further, the state of the granular material staying in the valve box 3 is confirmed, the contact pressure of the seal gasket 57 and the guide plate seal gasket 63, the space between the upper sliding surface 27 and the wedge plate sliding surface 33, and the guide plate slide. It is possible to determine whether or not the contact surface pressure between the moving surface 41 and the lower sliding surface 29 needs to be adjusted and checked.
Further, by rotating the valve stem 75 by 90 °, the valve rod 75 and the valve body 23 are disengaged from each other, and a space is created in this state where the valve body 23 is taken out from the open portion. Can be taken out. For this reason, it is possible to perform maintenance such as inspection inside the valve box or replacement assembly of internal parts without removing the valve box from the piping.
Incorporation of new parts can be easily performed by this reverse procedure. A valve stem detent 91 is fixed to the valve stem 75 with a taper pin 93 so that the connection with the valve body 23 is not removed during operation.

It is sectional drawing which shows the front of the gate valve concerning one Embodiment of this invention. It is a top view of FIG. The full open state of the gate valve concerning one Embodiment of this invention is shown, (a) is sectional drawing which shows a front, (b) is XX sectional drawing of (a), (c) is Y-- of (a). It is Y sectional drawing. The intermediate opening state of the gate valve concerning one Embodiment of this invention is shown, (a) is sectional drawing which shows a front, (b) is ZZ sectional drawing of (a), (c) is (a). It is UU sectional drawing. The full close state of the gate valve concerning one Embodiment of this invention is shown, (a) is sectional drawing which shows a front, (b) is VV sectional drawing of (a), (c) is W of (a). It is -W sectional drawing. It is a top view which shows the other side edge part of the valve body concerning one Embodiment of this invention. It is a fragmentary sectional view showing the seal gasket concerning one embodiment of the present invention. It is a fragmentary sectional view showing the guide plate seal gasket concerning one embodiment of the present invention. It is sectional drawing which shows the spiral wound gasket concerning one Embodiment of this invention. It is a front view which fractures | ruptures and shows the holding | maintenance part concerning one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the conventional gate valve.

DESCRIPTION OF SYMBOLS 1 Gate valve 3 Valve box 7 One side cover 19 Inclined surface 21 Wedge plate 23 Valve body 25 Guide plate 27 Upper sliding surface 29 Lower sliding surface 31 Valve body flow-path hole 33 Wedge plate sliding surface 35 Inclined support surface 37 Wedge Plate passage hole 39 Concave annular groove 41 Guide plate sliding surface 43 Guide plate passage hole 51 Adjustment bolt 53 Bolt 57 Seal gasket 59 Spiral wound gasket 61 Seal plate 63 Guide plate seal gasket 67 Guide plate 73 Moving means 83 Holding portion 89 Spring

Claims (5)

In a gate valve installed in a transportation line that transports fluid containing particulates in a coal gasification plant,
A valve box having an inflow portion and a discharge portion in which a flow path constituting a part of the transport line is formed;
A valve body that extends between the inflow portion and the discharge portion in an opening / closing direction orthogonal to the axial direction of the flow path and is movably provided in the opening / closing direction;
A wedge plate provided extending between the valve body and the inflow portion in the opening and closing direction;
A guide plate provided extending in the opening and closing direction between the valve body and the discharge portion;
Moving means that engages with the valve body and moves the valve body in an opening and closing direction;
The valve body is provided with a first sliding surface on the inflow portion side and a second sliding surface on the discharge portion side which are substantially orthogonal to the flow path and substantially parallel to each other, and are intermediate in the opening / closing direction. A valve body passage hole penetrating so as to constitute a part of the passage is provided on one side of the position,
The wedge plate has a third sliding surface in surface contact with the first sliding surface on the valve body side, and a height from the substantially intermediate position in the opening / closing direction on the inflow portion side to the other side. A wedge plate channel hole which is provided with a gradually decreasing inclined support surface and which penetrates from the inclined support surface toward the third sliding surface and constitutes a part of the channel, on one side in the opening and closing direction. Provided so that the third sliding surface exists at least at a length equal to or larger than the diameter of the valve body passage hole,
The guide plate has a fourth sliding surface that is in surface contact with the second sliding surface on the valve body side, and a guide plate channel hole that penetrates to constitute a part of the channel. The fourth sliding surface is provided on one side in the opening and closing direction so that the fourth sliding surface exists at least in a length equal to or larger than the diameter of the valve body passage hole.
An inclined surface facing the inclined support surface is formed at the inner end of the inflow portion,
A first seal member having elasticity is mounted between the inclined surface and the wedge plate concave annular groove provided surrounding the wedge plate channel hole of the inclined support surface,
A second seal member having elasticity is attached so as to surround the flow path between the guide plate and the discharge portion,
The valve box has a first urging means capable of urging the wedge plate to the other side in the opening / closing direction, and is disposed on the other side of the opening / closing direction of the first urging means, and the wedge plate is arranged in one of the opening / closing directions. A second urging means capable of urging to the side ,
The first seal member and the second seal member are constituted by a spiral gasket having a plurality of elasticity in the flow path axis direction and a metal seal plate interposed between the spiral gaskets. A gate valve characterized by The moving means is disposed on either one side or the other side of the valve body, and is detachably engaged with the valve body,
2. The gate valve according to claim 1, wherein an opening that can be opened and closed is provided on the opposite side of the valve box in the opening and closing direction. The thermal spray layer is provided in the surface of said 1st sliding surface, said 2nd sliding surface, said 3rd sliding surface, and said 4th sliding surface, The Claim 1 or Claim 2 characterized by the above-mentioned. The gate valve described. The flow path is formed in a substantially vertical direction in a form in which the discharge portion is disposed on the lower side,
The other end of the guide plate is positioned to extend to the other side of the guide plate channel hole,
The valve box is provided with a holding portion with a gap corresponding to the thermal expansion of the valve box between the guide plate and a substantially lower end on one side of the guide plate.
The partition according to any one of claims 1 to 3 , wherein a spring having a spring force for supporting the weight of the guide plate, the valve body and the wedge plate is provided between the holding portion and the guide plate. valve. The inner surface of the valve body where the valve body is facing, gate valve according to any one of claims 1 to 4, characterized in that the guide plates leaving a small gap is provided detachably.

Images