1
DESCRIPTION
GATE VALVE
TECHNICAL FIELD [0001]
The present invention relates to a gate valve utilized in an apparatus, such as a coke oven, that uses various gases (particularly high-temperature gases).
Priority is claimed on Japanese Patent Application No. 2009-235040, filed October 9, 2009, the content of which is incorporated herein by reference.
BACKGROUND ART [0002]
In coke ovens for iron manufacture, the coal carbonization gas (Coke Oven Gas, hereunder referred to as COG) that is generated at the time of carbonization of the coal is recovered at a collection piping and utilized as a fuel. At this time, since the generated COG is a high temperature of approximately 850°C or up to approximately 900°C, in principle it is possible to achieve energy savings by recovering the sensible heat of the gas. However, tar, which is a high-boiling gas, is contained within the COQ and this has a property in which, if the temperature of the COG decreases to 700°C or below, the tar within the COG is condensed. Once the tar is condensed, the properties change following condensation, and they commonly change to properties in which the tar does not easily evaporate even when reheated. Furthermore, the COG also has a property in which the carbon, including hydrocarbons such as methane, decomposes at high temperatures of 700°C or above, and is precipitated as solid carbon (soot) (this phenomenon is referred to

2 as coking). Since this solid carbon, once precipitated, is mutually strongly bonded, it does
not easily become a hydrocarbon even if the temperature is lowered again.
[0003]
In the conventional technology, supposing a case where the high-temperature COG is flowed through a pipeline installation (pipelines, valves, air blowers, and the like), this tar and solid carbon are deposited within the pipeline installation in large quantities. Consequently, the operation of the pipeline facility becomes difficult. Therefore, conventionally, when the COG generated in coke ovens is discharged from a riser tube of the coke oven, it is immediately water-cooled down to room temperature. At this time, the tar is condensed and separated from the COQ and is mixed into the cooling water and removed. Therefore, only the low-boiling gas (this is referred to as dry COG) within the room temperature COG is recovered as fuel. Since dry COG does not have any special operational problems, a general industrial pipeline facility can be applied, and the gas flow of the pipeline can be freely controlled. [0004]
On the other hand, in the riser tube, gas from which the tar has not been removed (here referred to as wet COG) is contacted against the riser tube inner surfaces. Therefore coking with respect to the riser tube inner surfaces cannot be avoided. Furthermore, there are cases where the temperature of the COG becomes low in the series of processes of the coal carbonization operation, and at this time, the condensate of the tar included in the COG is deposited on the riser tube inner wall surfaces, and a rigid fixed layer is formed. When the operation is continued in a state where these deposits are formed, the pipeline of the riser tube becomes obstructed. Therefore, in the pipeline of the riser tube, an operation that bums off the carbon deposited on the riser tube inner surfaces is necessary at frequent intervals, daily for example. Such problems of tar deposition and coking that occur in the

3 riser tube are not limited to the riser tube, and are problems that are common to pipelines
through which wet COG is flowed.
[0005]
For example, in a method of installing a flow regulating valve between a riser
tube and a dry main disclosed in Patent Document 1, the temperature of the COG flowing
through the flow regulating valve is already low as a result of spray water application.
Furthermore, since the flow-through of the gas cannot be blocked by the flow regulating
valve alone, a water sealed valve is separately required. An isolation valve for wet COG is
disclosed in Patent Document 2. However in this isolation valve, the valve seat and the
valve body are both continuously in contact with the wet COQ and severe coking and
condensing and solidifying of the tar occurring at these surfaces cannot be avoided.
Therefore frequent cleaning operations are necessary. Furthermore, in Patent Document 3,
waste heat recovery is achieved by providing air piping in the riser tube, and heating the air
that flows through the interior of the air pipe by means of the high-temperature COG flow
within the riser tube. However, in the case of this device, if the amount of cooling of the
COG is large, COG immediately condenses and solidifies on the air piping surfaces as tar,
thereby adhering to the surface of the air piping. As a result, in addition to the heat transfer
being inhibited, a problem arises in that the riser tube is blocked. Furthermore, there is a
problem in that only a small portion of the sensible heat of the COG can be recovered. In
this manner, in a case where the sensible heat of the high-temperature wet COG is utilized,
rather than recovering the waste heat, it is considered to be advantageous to promote a
useful chemical reaction (gas reforming) of the COG that can be performed only in
high-temperature conditions.
[0006]

4 Since it is necessary to open and close the pipeline at the riser tube, normally two
valves are provided, one at the riser tube top cover and one at the dry main cover. The riser
tube top cover dissipates the residual gas within the coke oven following completion of
carbonization, into the atmosphere so that it bums, and the space between the riser tube top
cover and the riser tube is water sealed when the coal is being carbonized. Alternatively, in
order to avoid adhesion of the riser tube top cover to the riser tube due to precipitation of
the deposits, a construction in which a spacing is provided beforehand between the riser
tube and the cover, so that the COG is not completely sealed, has been formerly employed.
Furthermore, the dry main cover is a cover of the pipeline that connects the riser tube and
the dry main, and this is also water sealed in a case where the pipeline is closed. In this
manner, in the conventional technology, as a construction of a valve that may contact with
wet COG, a construction in which the valve is maintained at a low temperature, or is not
completely sealed, is used.
[Prior Art Documents]
[Patent Documents]
[0007]
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2004-107466.
[Patent Document 2] Japanese Examined Utility Model Application, Second Publication No. S62-39077.
[Patent Document 3] Japanese Unexamined Utility Model Application, First Publication No. S58-7847. [Non-Patent Documents] [0008]
. [Non-Patent Document 1] Association of Powder Process Industry and

5 Engineering, Japan: Fluidized Bed Handbook, Baifukan, 1999.
DISCLOSURE OF INVENTION [Problems to be Solved by the Invention] [0009]
In order to utilize the sensible heat of the COG in a wet COG state, a valve that controls the flow-through of the high-temperature state wet COG within the COG pipeline and can open and close the pipeline is essential. However, in valves (covers) of the conventional technology, problems occur, such as the wet COG being unable to be completely sealed, the wet COG being made a low temperature, or it being necessary to frequently terminate the operation (coal carbonization) and remove the tar or the solid carbon deposited on the valve inner surfaces. [0010]
Therefore, the present invention takes into consideration the above problems with an object of providing, between ducts, a gate valve through which it is possible to flow a gas for an extended period, in particular a wet COG from room temperature to approximately 850°C or approximately 900°C. [Means for Solving the Problem] [0011]
To address the above problems and to achieve the object, the present invention adopts the following measures.
That is to say, (1) a gate valve according to an aspect of the present invention comprises: a granular sealant that is made to flow in a temperature range from room temperature to 900 °C; a valve casing wherein the sealant is stored at a bottom portion thereof; a first duct which is connected to the valve casing and through which a gas flows

6 in from the outside toward the inside of the valve casing; a second duct which is connected
to the valve casing and through which the gas flows out from the inside toward the outside
of the valve casing; a valve body which lowers down to a valve body lowering position
where it is at least partially buried in the sealant and blocks the flow of the gas from the
first duct toward the second duct, and rises to a valve body rising position where it is
arranged above a siirface of the sealant and allows the gas to flow in from the first duct
toward the second duct; and a valve body raising and lowering device that raises and
lowers the valve body between the valve body lowering position and the valve body rising
position.
(2) Preferably the gate valve disclosed in (1) above further comprises: a fluidized bed gas supply switching mechanism that has fluidized bed gas piping which supplies a fluidized bed gas from the exterior of the valve casing to an interior to fluidize the sealant, and the fluidized bed gas supply switching mechanism switches the flow of the fluidized bed gas, so that the fluidized bed gas is supplied to an interior of the valve casing through the fluidized bed gas piping during a movement period in which the valve body moves between the valve body lowering position and the valve body rising position, and the fluidized bed gas is not supplied to the interior of the valve casing in periods other than the movement period.
(3) A gate valve according to an aspect of the present invention comprises: a valve casing which includes at least a fluidized bed that is made to flow a granular sealant that has little physical property change over a temperature range from room temperature to a high temperature of 900°C;
a high-temperature gas outlet pipe connected to the valve casing above the surface of the fluidized bed; a high-temperature gas inlet pipe connected to the valve casing such that, at least in an opened state of the valve, the aperture is arranged above the

7 surface of the fluidized bed; a valve body that, in a closed state of the gate valve, is
arranged at a valve body lowering position, which is a position in which the valve body is
at least partially buried in the sealant such that the flow-through of the high-temperature
gas between the high-temperature gas inlet pipe and the high-temperature gas outlet pipe is
blocked using the sealant, and additionally in an opened state of the gate valve, is arranged
at a valve body rising position, which is a position in which the entire valve body is present
above the surface of the sealant; a valve body raising and lowering device that changes the
arrangement of the valve body between the valve body lowering position and the valve
body rising position; fluidized bed gas piping that is coimected to a lower portion of, or
below, the sealant, for supplying fluidized bed gas which combusts carbide mixed into the
sealant, to the valve casing; and a fluidized bed gas switching mechanism that switches the
gas that combusts the carbide, to a supplying state or a stopped state.
(4) Preferably in the gate valve disclosed in (1) or (2) above, when the valve body
lowers to the valve body lowering position, a space of an interior of the housing is divided
■ -into a first space which includes an interior of the valve body, and a second space which is a remaining space.
(5) Preferably in the gate valve disclosed in (1) or (2) above, when the valve body lowers to the valve body lowering position, the sealant which has been pushed out by the valve body, divides a space of the periphery of the valve casing into a first space which includes an interior of the first duct, and a second space which includes an interior of the second duct.
(6) Preferably in the gate valve disclosed in from (1) to (5) above, a pad that inhibits dispersal of the sealant is loaded on an upper surface of the sealant.
(7) Preferably in the gate valve disclosed in from (2) to (5) above, the fluidized bed gas is an oxidative gas that contains oxygen.

8 (8) Preferably in the gate valve disclosed in from (1) to (5) above, the sealant is
composed of one type, or two or more types, selected from alumina, magnesia, zirconia,
stabilized zircon, titanium oxide, silicon nitride, and silicon carbide.
[Effects of the Invention]
[0012]
According to the gate valve disclosed in (1) above, a granular sealant that can be fluidized in a temperature range from room temperature to a high temperatiire of approximately 850°C or approximately 900°C is stored at the bottom portion of the valve casing. When the gate valve is in an opened state, the valve body is raised to the valve body rising position, and the gas flows between the first duct and the second duct. Furthermore, when the gate valve is in a closed state, the valve body is lowered to the valve body lowering position, and the flow of the gas between the first duct and the second duct is blocked. At this time, even when tar or solid carbon is generated within the sealant, since the sealant can be fluidized, the tar or the solid carbon is dispersed within the sealant by means of the sealant flowing. Consequently, there is no need to remove, tar. or solid carbon within the valve casing, and hence it becomes possible to flow a gas (particularly a wet COG from room temperature to approximately 850°C) for long periods within a pipeline.
Furthermore, by using a granular material as the sealant of the gate valve, in which large changes in the physical properties, such as phase changes, thermal decomposition, sintering, or phase transformations, do not occur even at a high temperature of approximately 850°C or approximately 900°C, the sealing properties of the valve are ensured over a wide temperature range. In contrast, in sealing methods of the conventional technology, such as in the case of a water sealed valve for example, since the water cannot be maintained as a liquid phase at high temperatures as a result of a phase

9 change, water sealed valves cannot be applied. Moreover, even in a case where solid
granules are utilized as a sealant, in a case where granules with a phase transformation
material property, for example, are used over a temperature range from room temperature
to 850°C, the granules are gradually crushed as a result of unavoidable sudden changes in
the density at the time the phase change occurs. Consequently, there is a problem in that
the particle size distribution of the granules cannot be maintained at an optimal fixed value,
and hence granules with a phase transformation material property are not preferable as a
sealant.
[0013]
Furthermore, in the gate valve, it is normal to use different materials in
combination between the components of the gate valve according to the required functions.
In a case where such a gate valve is utilized in a broad temperature range, differences in
thermal expansion between the components occur. Consequently, with regard to the
contact between the components, such as the contact between the valve seat and the valve
body for example, it is difficult in mechanical processing, to maintain so-called fit in the
same state over a broad temperature range. Moreover, in a case where the valve is utilized
at a high temperature of approximately 850°C or 900°C, in the long term, deformation of
the material due to creep cannot be avoided. Therefore even if the operation temperature is
constant, it is difficult to maintain the same fit over the long term. Gate valves of the
conventional technology have a construction in which sealing of a working fluid is
performed by clamping the valve body to the valve seat. If the fit of the valve changes, a
gap opens between the valve body and the valve seat, and the sealing becomes incomplete.
Furthermore, a problem arises in which the contact force between the valve body and the
valve seat becomes excessive, such that the valve body becomes unable to move. On the
other hand, in the gate valve of an embodiment of the present invention, essentially, the

10 sealing is performed by burying the valve body in a layer of a sealant (depth of more than
30 mm and less than 1 m for example) with a high mobility. Therefore there is no need to
consider the fit, and the problems mentioned above can be avoided.
[0014]
Generally, since the wet COG contacts the sealant, coking or tar condenses and solidifies on the sealant. However, since a comparatively large amount of a granular sealant is used, coking and tar is not condensed and solidified. Hence it is insusceptible to the adverse effects toward the sealing property. That is to say, in the gate valve of an embodiment of the present invention, the sealant is fluidized and stirred. Therefore even in a case where coking occurs on a portion of the sealant on the surface layer, the precipitated carbon is rapidly dispersed into the entire layer. Consequently, the effects of the deterioration of the sealing property and the fluidity of the sealant can be reduced. Furthermore, in the gate valve of an embodiment of the present invention, by frequently burying the valve body in the sealant, an effect in which the sealant polishes the valve body can be obtained. Therefore there is the effect that deposits on the valve body surface are removed. [0015]
In a case where a granular sealant is used, the gas flow that flows through the sealant layer cannot be completely blocked, as in a liquid seal. However, by providing a comparatively thick (deep) sealant layer (depth of more than 30 mm and less than 1 m for example) to increase the gas flow resistance, this flow amount is reduced to a level that can be ignored so that in effect gas sealing is performed. Therefore, in a case where gas sealing is performed by the sealant layer, wherein the valve body is buried in the sealant as with the gate valve disclosed in (1) above, it is preferable for the valve body to be buried comparatively deeply in the sealant, for example to a position of a depth of more than 10

11
mm and less than 1 m from the surface of the sealant.
Generally, in order to deeply insert a valve body with a comparatively large cross-sectional area into a stationary sealant layer, a large thrust and a device with a high rigidity are necessary. Therefore, the device becomes large. Furthermore, since the contact stress between the sealant and the valve body also becomes large, problems occur such as wearing of the valve body progressing readily. On the other hand, in the gate valve disclosed in (1) above, by fluidizing the sealant within the valve casing at the time the valve body is moved within the sealant, the resistance when the valve body moves within the sealant can be significantly reduced. Consequently, the problems mentioned above can be avoided. [0016]
Furthermore, in the case of the gate valve disclosed in (1) above, the valve body raising and lowering device lowers the valve body and at least partially buries the valve body in the sealant, so that the flow of gas between the first duct and the second duct is blocked. Moreover, the valve body raising and lowering device raises the valve body so that the gas flows between the first duct and the second duct. In this manner, by fiimishing the valve body raising and lowering device, it is possible to easily and certainly raise and lower the valve body between the valve body lowering position and the valve body rising position. [0017]
In the case of the gate valve disclosed in (2) above, by means of the fluidizing gas supply switching mechanism corresponding to the movement of the valve body, the fluidized bed gas is supplied into the valve casing through the fluidized bed gas piping. In this manner, by supplying the fluidized bed gas into the valve casing as necessary, the sealant can be efficiently made a fluidized bed.

12 In the case of the gate valve disclosed in (4) above, at the time the valve body is
lowered to the valve body lowering position, the interior of the valve casing is divided by
means of the valve body into the first space which includes the interior of the valve body,
and the second space which includes the interior of the valve casing. Therefore the flow of
gas between the first duct and the second duct is blocked. Consequently, contamination or
corrosion of the valve body and the like, by the gas (gas components of the wet COG for
example) can be reduced.
Furthermore, in the case of the gate valve disclosed in (5) above, at the time the
valve body is lowered to the valve body lowering position, the space of the valve casing
periphery is divided by means of the sealant pushed out by the valve body, into the first
space which includes the interior of the first duct, and the second space which includes the
interior of the second duct. Therefore the flow of gas between the first duct and the second
duct is blocked. Consequently, contamination or corrosion of the valve body and the like,
by the gas (gas components of the wet COG for example) can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS [0018]
FIG. 1 is a schematic view showing a state in which the gate valve of a first embodiment of the present invention is opened.
FIG. 2 is a schematic view showing a state in which the gate valve is closed.
FIG. 3 is a schematic view showing a state in which the gate valve of a second embodiment of the present invention is opened.
FIG. 4 is a schematic view showing a state in which the gate valve is closed.
FIG. 5 is a schematic .view showing a state in which the gate valve of a third embodiment of the present invention is opened.

13 FIG. 6 is a schematic view showing a state in which the gate valve is closed.
FIG. 7 is a schematic view showing a state in which the valve is opened according to a fifth embodiment of the present invention.
FIG. 8 is a schematic view showing a state in which the valve is closed according to the fifth embodiment of the present invention.
FIG. 9 is a schematic view of a device configuration illustrating another embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION [0019]
Hereunder is a detailed description of the preferred embodiments of the present
invention with reference to the attached drawings. In the present specification and the
drawings, components having substantially the same fianctional configuration are denoted
by the same reference symbols, and duplicate descriptions are omitted.
[0020] ^
(First Embodiment)
An opened state of a gate valve 100 is shown in FIG. 1, and a closed state of the gate valve 100 is shown in FIG. 2. Furthermore, the arrow F in FIG. 1 shows the direction of the flow of the working gas (gas components of the wet COG for example).
The gate valve 100 described in the present embodiment is a high-temperature furnace gas gate valve used in a high-temperature fiimace. This high-temperature furnace gas gate valve 100 is furnished with: a granular sealant 5, which is made to flow in a temperature range from room temperature to a high temperature of approximately 850°C or approximately 900°C; a valve casing 1 in which the sealant 5 is stored at a bottom portion 1 A; a high-temperature gas inlet pipe (first duct) 3 that is coimected to the valve

14 casing 1 through which a high-temperature working gas (gas) flows in; a high-temperature
gas outlet pipe (second duct) 4 that is connected to the valve casing 1 through which a
high-temperature working gas flows out; and a valve body 2 that moves in a vertical
direction. Hereunder, the high-temperature gas inlet pipe 3 may be simply described as an
"inlet pipe 3", and the high-temperature gas outlet pipe 4 may be simply described as an
"outlet pipe 4".
With regard to the high-temperature gas inlet pipe 3, at least when the gate valve 100 is in an opened state, the aperture 3 A is arranged above a surface 5 A of the sealant 5, and the interior IB and the exterior IC of the valve casing 1 are connected. Furthermore, the high-temperature gas inlet pipe 3, specifically, extends from the bottom portion 1A of the valve casing 1 to the interior IB of the valve casing 1 through the sealant 5.
The high-temperature gas outlet pipe 4 is provided on a side surface ID of the valve casing 1 above the surface 5 A of the sealant 5, and connects the interior IB and the exterior IC of the valve casing 1.
Furthermore, during the closed state of the gate valve 100 shown in FIG. 2, the valve body 2 is lowered to the valve body lowering position, where it is at least partially buried in the sealant 5 and blocks the flow of the high-temperature working gas between the inlet pipe 3 and the outlet pipe 4. Moreover, during the opened state of the gate valve 100 shown in FIG. 1, the valve body 2 is raised to the valve body rising position, where it is arranged above the surface 5 A of the sealant, and allows the flow of the working gas between the inlet pipe 3 and the outlet pipe 4. The interior 2A of the valve body 2 is hollow, and when the gate valve 100 is closed, the inlet pipe 3 is inserted into the interior 2A of the valve body 2. [0021] (Construction of Gate Valve)

15 As shown in FIG. 1, when the gate valve 100 is opened, the high-temperature
working gas flows into the valve casing 1 from the high-temperature gas inlet pipe 3, and
flows out from the high-temperature gas outlet pipe 4. The position of the valve body 2 at
this time is referred to as the valve body rising position. As shown in FIG. 2, when the gate
valve 100 is closed, the valve body 2 in which the lower end 2B is buried in the sealant 5,
divides the space of the interior IB of the valve casing 1 into a first space (a space that
includes the interior of the valve body 2) 19 on the inlet pipe 3 side and a second space 20
(a space that includes the interior of the valve casing 1) on the outlet pipe 4 side, and the
flow of the high-temperature working gas from the inlet pipe 3 to the outlet pipe 4 is
blocked. The position of the valve body 2 at this time is referred to as the valve body
lowering position. Here, the first space 19 is formed by the inner wall of the valve body 2,
the outer wall of the inlet pipe 3, and the surface 5A of the sealant 5, and the second space
20 is formed by the inner wall of the valve casing 1, the outer wall of the valve body 2, and
the surface 5 A of the sealant 5.
Small quantities of the working gas may flow through the gaps (interior) of the
sealant 5. However, in a case where the burial depth of the valve body 2 in the sealant 5 is
sufficient, the gas flow resistance of the sealant 5 is sufficiently large, and in effect, gas
sealing can be achieved. For example, even in a case where a pressure difference of 100 Pa
is applied between the first space 19 on the high-temperature gas inlet pipe 3 side and the
second space 20 on the high-temperature gas outlet pipe 4 side, it is possible to make the
working gas flow rate flowing through the fluidized bed of the sealant 5 less than 1 mm/s.
The burial depth of the valve body 2 in the sealant 5 can be made more than 30 mm and less
than 1 m for example. In a case where the burial depth is a shallower burial amount than 30
mm, the sealing property of the sealant 5 is insufficient, and in a case where the burial
depth is a deeper burial amount than 1 m, the device becomes too expensive compared to

16 the sealing performance that can be achieved. Therefore, by making the burial depth more
than 30 mm and less than 1 m, the sealing property is improved, the costs are reduced, and
a gate valve 100 with an excellent sealing performance can be provided.
[0022]
(Fluidized bed Gas Supply Switching Mechanism)
The fluidized bed gas supply switching mechanism S is furnished with; a fluidized bed gas supply source 9, a fluidized bed gas piping 11 that supplies the fluidized bed gas, which fluidizes the sealant 5, to the valve casing 1,21 and 31, and that connects the interior IB, 2 IB and 3 IB of the valve casing 1,21 and 31 to the exterior IC, 21C and 31C, and a fluidized bed gas valve 12. The fluidized bed gas supply switching mechanism S supplies fluidized bed gas to the interior IB of the valve casing 1 through the fluidized bed gas piping 11 during the movement period, in which the valve body 2, 22 and 32 moves between the valve body lowering position and the valve body rising position, and in periods other than the movement period, the flow of the fluidized bed gas is switched such that the fluidized bed gas is not supplied to the interior IB of the valve casing 1. That is to say, the fluidized bed gas supply switching mechanism S switches the gas flow rate supplied to the fluidized bed gas supply opening 10 provided on the lower portion IF of the valve casing 1.
The switching of the gas flow rate is directly achieved by changing the degree of opening of the fluidized bed gas valve 12. In the present embodiment, since the fluidized bed gas supply is stopped during periods where the valve body 2 is not raised or lowered, a fimction that stops the gas is necessary for the fluidized bed gas valve 12. In a case where the degree of opening of the valve is made the two types of open or close, a gate valve can be used for the fluidized bed gas valve 12. Furthermore, in a case where the degree of opening of the valve is set at finer steps, the fluidized bed gas valve 12 can be made a flow

17 regulating valve furnished with a shutoff function. Commercially available products can
be used for these gate valves and flow regulating valves. Furthermore, in a case where the
degree of opening of the valve is adjusted using a flow regulating valve, a separate flow
meter can be provided to the pipeline, and the degree of opening of the valve can be
controlled based on this output value. The method of adjusting the degree of opening of
the valve may be performed manually, or may be automatically controlled by providing a
separate control device and a valve actuator.
[0023]
Furthermore, even in a case where the gas for combusting the carbide is used as the fluidized bed gas, the same mechanism as mentioned above can be used. [0024]
The fluidized bed gas piping 11, which supplies the fluidized bed gas for fluidizing the sealant 5 and the fluidized bed gas for combusting the carbide within the sealant 5, to the valve casing 1 may be separately provided. Alternatively, the fluidized bed gas piping 11 can. be shared with the assimiption that a gas supply switching mechanism, such as a three-way valve, is separately supplied for each supply source of the fluidized bed gas type. [0025]
In order to improve the gas sealing property, when the valve is closed, that is to say, when the high-temperature gas inlet pipe 3 is inserted into the interior 2 A of the valve body 2, a cover 18 that makes contact with the upper end of the high-temperature gas inlet pipe 3 may be provided on the interior 2A of the valve body 2. Since the formation of deposits from coking or tar condensation and solidification on such a cover 18 or the surface of the high-temperature gas inlet pipe 3 cannot be avoided, it is generally difficult to completely block the flow of the working gas into the outlet pipe with the cover 18 alone.

18 However, since working gas that has flowed in from the inlet pipe 3 makes contact with the
cover 18 at the time the working gas flows through the gap between the cover 18 and the
upper end of the high-temperature gas inlet pipe 3, a pressure loss occurs. Furthermore,
the working gas flowing from the gap toward the outlet pipe 4 is blocked by the sealant. In
this manner, by providing both the cover 18 and the sealing property of the sealant 5, the
sealing property of the entire high-temperature furnace gas gate valve 100 can be
improved.
[0026]
In order to raise and lower the valve body 2 between the valve body rising position and the valve body lowering position, a valve body raising and lowering device 8 connected to the valve body 2 is operated. Bellows 14 are provided between the valve body 2 and the valve casing 1 to maintain a hermetically sealed state of the valve casing 1. Furthermore, the bellows 14 absorbs the effect of relative displacement between the valve body 2 and the valve casing 1. That is to say, the bellows 14 have an elastic property that expands and contracts in the extending direction of the bellows 14, while maintaining the inside of the bellows 14 in an airtight state. Therefore, even if the valve casing 1 and the valve body 2 move relatively, the space of the interior IB of the valve casing 1 is maintained in a gas-tight state.
When the valve body 2 is moved from the valve body rising position to the valve body lowering position, if the sealant 5 is in a stationary state, the driving resistance is large, and it is not preferable since a large and powerful driving device becomes necessary. Therefore, in the present embodiment, at the time the valve body 2 is raised and lowered within the sealant 5, the sealant 5 that is stationary in the interior IB of the valve casing 1 is fluidized and is made a fluidized bed. By raising and lowering the valve body 2 within the sealant 5, which has been made a fluidized bed, the force (resistance) against the driving

19 force is reduced. Thereafter, the bed fluidization of the sealant 5 is stopped, and the sealing
property of the sealant 5 is recovered. Thus, the valve body 2 can be stably inserted deep
into the layer of the sealant 5 with a comparatively small driving force. In order to make
the valve casing 1 a fluidized bed, the fluidized bed gas is flowed into the fluidized bed gas
piping 11, and the fluidized bed gas is supplied into the valve casing 1 from the fluidized
bed gas inlet 10 on the lower portion IF of the valve casing 1. The fluidized bed gas
supplied into the valve casing 1 is dispersed by a dispersion plate 6, and when it flows
through the layer of the sealant 5 arranged on the dispersion plate 6, the sealant 5 is
fluidized by the fluid resistance,
[0027]
When the gate valve 100 shown in FIG. 2 is closed, even if the fluidized bed gas
is supplied to the fluidized bed of the sealant 5 in this manner, the gas cannot flow out into
the first space 19 on the inlet pipe 3 side. Therefore there is a case where the sealant 5 of
the region R sandwiched by the inner wall of the valve body 2 and the outer wall of the
inlet pipe 3 is not fluidized. In such a case,,there is a possibility of the sealant 5 that is not
fluidized to move upward accompanying the rising of the valve body 2, and a portion of the
sealant 5 to drop onto the aperture portion 3 A of the inlet pipe 3. In order to prevent this
phenomenon, a projection 17 may be provided on the upper end peripheral portion of the
inlet pipe 3 toward the outside. By providing the projection 17, accompanying the rising of
the valve body 2, the sealant 5 that is attached to the inside of the valve body 2 can be
forcibly dropped prior to the lower end 2B of the valve body 2 being positioned above the
aperture portion 3 A of the inlet pipe 3. Consequently, the dropping of the sealant 5
attached to the inside of the valve body 2 into the inlet pipe 3 from the aperture portion 3 A
can be prevented.

20 In general, the pull-out resistance when such a pull-out is performed is a vastly
smaller value compared to the driving force necessary for deeply inserting the valve body
2 into the stationary sealant 5. Consequently, it is not necessary to use an excessively
powerful valve body raising and lowering device 8 in order to perform such a pull-out.
[0028]
In the present embodiment, when the gate valve 100 is opened, the working gas is flowed into the valve casing 1 from the high-temperature gas inlet pipe 3 and the working gas is flowed out from the high-temperature gas outlet pipe 4. In contrast to such an operation, a flow path system may be employed wherein when the gate valve 100 is opened, the high-temperature working gas is flowed into the valve casing 1 from the high-temperature gas outlet pipe (first duct) 4 and the working gas is flowed out from the high-temperature gas inlet pipe (second duct) 3. Furthermore, in the present embodiment, the opening and closing of the gate valve is achieved by raising and lowering the valve body 2 using the valve body raising and lowering device 8. In contrast to such a construction, as a valve there are no problems even if the valve body 2 is fixed, and the opening and closing of the gate valve is performed by raising and lowering the valve casing 1 by means of a separately provided valve casing raising and lowering device. In this case, a bellows that expands and contracts (absorbing the relative displacement) accompanying the raising and lowering of the valve casing 1 may be provided separately between the high-temperature gas inlet pipe 3 and the valve casing 1, and between the high-temperature gas outlet pipe 4 and the valve casing 1 for example. [0029] (Second Embodiment)
In the state of FIG. 2, the gas which is able to combust the carbonaceous materials as a fluidized bed gas, is supplied to the valve casing 1 from the fluidized bed gas

21 inlet 10 via the fluidized bed gas piping 11. The fluidized bed gas passes through the
interior of the sealant 5 and combusts and removes the carbonaceous materials mixed into
the sealant 5. As a result of the combustion, the generated carbon dioxide gas is discharged
to the outside of the valve from the outlet pipe 4 along with the fluidized bed gas reaching
the upper surface of the sealant 5. In the present embodiment, the fluidized bed gas is
supplied in a state in which the valve body 2 is not moved within the sealant 5. Therefore
it is not necessary to fluidize the sealant 5 by means of the fluidized bed gas. Consequently,
the supplied quantity of the fluidized bed gas can be set smaller than the flow rate that can
fluidize the sealant 5. As a result, by adjusting the supplied quantity of the fluidized bed
gas, the combustion rate of the carbonaceous materials mixed into the sealant 5 can be
made a preferred range. For example, by setting the fluidized bed gas supplied quantity
sufficiently small, the overheating of the valve interior resulting from the combustion of
the carbonaceous materials can be prevented.
[0030]
(Third Embodiment)
An opened state of a gate valve 200 is shown in FIG. 3, and a closed state of the gate valve 200 is shown in FIG. 4. Furthermore, the arrow F in FIG. 3 shows the direction of the flow of the working gas. [0031]
The present embodiment uses a portion of a high-temperature gas inlet pipe (flrst duct) 23 as the valve body. Specifically, the high-temperature gas inlet pipe 23 extends from an upper portion 21D of a valve casing 21 upwards toward an interior 21B and the upper portion 21D of the valve casing 21, and the lower end 23C side of the high-temperature gas inlet pipe 23 is inserted into the interior 21B of the valve casing 21 and an upper end 23B is connected to an exterior 21C. As a result of this configuration, the

22 high-temperature working gas is flowed into the interior 2 IB of the valve casing 21 from
the lower end 23C via the upper end 23B of the high-temperature gas inlet pipe 23.
When the gate valve 200 is opened, the high-temperature working gas flows into the valve casing 21 from the high-temperature gas inlet pipe 23, and flows out from a high-temperature gas outlet pipe (second duct) 24. The position of the valve body (high-temperature gas inlet pipe 23) at this time is referred to as the valve body rising position. When the gate valve 200 is closed, as a result of the lower end 23 C of the high-temperature gas inlet pipe 23 being buried in the sealant 5, the interior 2 IB of the valve casing 21 is divided into a first space 19 (a space including the interior of the valve body 22) on the high-temperature gas inlet pipe 23 side, and a second space 20 (including the interior of the valve casing 21) on the high-temperature gas outlet pipe 24 side. Consequently, the flow-through of the high-temperature working gas from the high-temperature gas inlet pipe 23 to the high-temperature gas outlet pipe 24 is blocked. The position of the valve body (high-temperature gas inlet pipe 23) at this time is referred . -. to as the valve body lowering position. The raising and lowering of the high-temperature gas inlet pipe 23 is achieved by means of a valve body raising and lowering device 8 connected to the high-temperature gas inlet pipe 23. The change in the relative position of the valve casing 21 and the inlet pipe 23 is absorbed by a bellows 14, and the sealing properties of the valve casing 21 are ensured. The burial amount of the valve body (high-temperature gas inlet pipe 23) into the sealant 5, and the positional relationship between the high-temperature gas outlet pipe 24 and the fluidized bed of the sealant 5, are the same as in the first embodiment. [0032]
As shown in FIG. 4, when the gate valve 200 is in a lowered state, there is a case where even when fluidization of the sealant 5 is attempted, the sealant 5 within the

23 high-temperature gas inlet pipe 23 is not fluidized (particularly prominent in cases where
differences in the quantity of thermal expansion occur between the high-temperature gas
inlet pipe 23 and the sealant 5, and the sealant 5 receives a compressive force). At this time,
if the high-temperature gas inlet pipe 23 is raised, the sealant 5 rises together with the
high-temperature gas inlet pipe 23 without dropping. Further, irrespective of the gate
valve 200 being opened, the sealant 5 remains in the interior 23D of the high-temperature
gas inlet pipe 23, and a problem occurs in that the high-temperature gas inlet pipe 23 is
blocked. In order to prevent this phenomenon, a sealant removing device 15 (sealant
removing member) that is provided on the bottom portion 21A of the valve casing 21 and
is inserted into the interior 23D of the inlet pipe 23, at least in the closed state of the gate
valve 200, may be provided on the dispersion plate 6. In the sealant removing device 15,
the diameter of the upper end is set larger than the lower end. Consequently, when the
high-temperature gas inlet pipe 23 is raised, the central portion of the sealant 5 lifted up
together with the high-temperature gas inlet pipe 23 that is remaining in the interior 23 D of
the. high-temperature gas inlet pipe 23. is scraped off by the upper end of the sealant.
removing device 15. When a portion of the sealant 5 is scraped off, the compressive force
acting on the sealant 5 is unloaded. Consequently, the sealant 5 bound to the interior of the
high-temperature gas inlet pipe 23 drops as a result of gravity, and the blocking of the
high-temperature gas inlet pipe 23 can be avoided. It is preferable for the upper end of the
sealant removing device 15 to be arranged above the surface 5 A of the sealant 5 when it is
in a stationary state in which the sealant 5 is not fluidized.
[0033]
In the same manner as the first embodiment, the flow direction of the
high-temperature working gas may be inverted (a flow path system that flows the working
gas out from the high-temperature gas outlet pipe 24 to the high-temperature gas inlet pipe

24 23). Furtheraiore, it is not a problem if the valve casing 1 is raised and lowered instead of
the valve body (high-temperature gas inlet pipe 23).
[0034]
(Fourth Embodiment)
An opened state of a gate valve 300 is shown in FIG. 5, and a closed state of the gate valve 300 is shown in FIG. 6. Furthermore, the arrow F in FIG. 5 shows the direction of the flow of the working gas. [0035]
The present embodiment differs from the first embodiment in the position of a high-temperature gas inlet pipe 33 (first duct) and the configuration of a valve body 32. That is to say, as shovm in FIG. 5, an inlet pipe 33 is provided on a side surface 3 IE of a valve casing 31. Furthermore, as shown in FIG. 6, by means of the valve body 32 moving from an upper portion 3 ID of the valve casing 31 toward a bottom portion 31 A, the valve body 32 is buried in the sealant 5. As a result of the valve body 32 being buried in the sealant 5, the position of the surface 5 A of the. sealant 5 rises, and the sealant 5 flows into the interior of the inlet pipe 33 and into the interior of an outlet pipe 34. Consequently, an aperture 33A of the inlet pipe 33 and an aperture of the 34A of the outlet pipe 34 are blocked.
Furthermore, in the stationary state shown in FIG. 5 in which the sealant 5 is not fluidized, the surface 5 A of the sealant 5 is positioned such that it does not flow into the aperture 33 A of the inlet pipe 33 or into the aperture 34A of the outlet pipe (second duct) 34.
When the gate valve 300 shown in FIG. 6 is closed, the interior 3 IB of the valve casing 31 is divided by the sealant 5 excluded by the valve body 32, into a first space 19 (a space including the interior of the high-temperature gas inlet pipe 33) on the

25 high-temperature gas inlet pipe 33 side, and a second space 20 (a space including the
interior of the high-temperature gas outlet pipe 34) that includes the interior of the
high-temperature gas outlet pipe 4. When the gate valve 300 shown in FIG. 5 is opened,
the high-temperature working gas flows into the valve casing 31 from the
high-temperature gas inlet pipe 33 and flows out from the outlet pipe 34. The position of
the valve body 32 at this time is referred to as the valve body rising position. When the
gate valve 300 is closed, the valve body 32 with the lower end 32A buried in the sealant 5
excludes (pushes out) a portion of the sealant 5 into the high-temperature gas inlet pipe 33
and the high-temperature gas outlet pipe 34, so that the aperture 33A of the
high-temperature gas inlet pipe 33 and the aperture 34A of the high-temperature gas outlet
pipe 34 are blocked. Consequently, the space of the valve casing 31 periphery is divided
into the first space 19 on the high-temperature gas inlet pipe 33 side and the second space
20 on the high-temperature gas outlet pipe 34 side, and the flow of the high-temperature
working gas from the high-temperature gas inlet pipe 33 to the high-temperature gas outlet
pipe 34 is blocked. The position of the valve body at this -time is referred to as the valve
body lowering position. Furthermore, the "space of the valve casing 31 periphery" is a
space that is in communication with the valve casing 31 (including the interior space of the
valve casing 31 itself), and refers to a space in which the sealant 5 is movable. The space
of the valve casing 31 periphery is, specifically, the space within the inlet pipe 33 and the
outlet pipe 34 in the present embodiment for example. The raising and lowering of the
valve body 32 is achieved by a valve body raising and lowering device 8 connected to the
valve body 32. By providing a bellows 14, the change in the relative position of the valve
casing 31 and the valve body 32 is absorbed, and the sealing properties of the valve casing
31 are ensured.
[0036]

26 In the same manner as the first and the third embodiments, it is not a problem if
the flow direction of the high-temperature working gas is inverted (a flow path system that
flows the working gas out from the high-temperature gas outlet pipe 34 to the
high-temperature gas inlet pipe 33), or if the valve casing 31 is raised and lowered instead
of the valve body 32.
[0037]
(Fifth Embodiment)
The present embodiment is described using FIG. 7 (opened state) and FIG. 8 (closed state) for a gate valve 400 in which a pad 121 has been added to the device of FIG. 1 and FIG. 2. The pad 121 is configured by two pads, namely an inside ring-shaped pad, and an outside ring-shaped pad. The valve can be opened and closed by passing the valve body 2 through between the inner and the outer pads. The pad 121 is loaded on the sealant 5. The working gas flowed into the valve casing 1 from the inlet pipe 3 generates a vigorous gas flow within the valve casing 1. However, in the present embodiment, due to the pad 121, this vigorous gas flow does not directly make contact with the sealant 5 ,. and hence the amount of sealant 5 that is dispersed by the gas flow within the valve casing 1 can be inhibited. [0038] (Sixth Embodiment)
The present embodiment is described using the device of FIG. 9, in which the valve casing 1 of the device of FIG. 1 and FIG. 2 is arranged within a heating furnace 124. The temperature of the heating furnace 124 is made room temperature, and a fan 122 is connected to the outlet pipe 4 to aspirate the air. After aspirating room temperature air from the inlet pipe 3 serving as the working gas, and introducing this to the valve casing 1, it is discharged from the outlet pipe 4. Any dispersed sealant 5 is recovered by providing a

27 filter 123 in the outlet pipe 4 outlet. The outlet pipe 4 is provided with a flow meter 125
and a pressure gauge 126. By adopting such a device configuration, the characteristics of
the gate valve can be measured. That is to say, by performing aspiration with the fan 122 in
the opened state of the valve, and using the measured values of the flow rate and the
pressure at this time, the pressure loss coefficient of the valve can be obtained (pressure
loss coefficient = 2 x pressure measured value / [inlet pipe flow rate]^). Next, by aspirating
with the fan 122 in the closed state of the valve, and using; the flow rate at this time, the
measured value of the pressure, and the pressure loss coefficient obtained above, the leak
rate of the valve can be obtained. Furthermore, by performing aspiration with the fan 122
for a fixed time, and weighing the mass of the particles collected at the filter 123 in this
period by taking out the filter, the sealant dispersion mass flow rate can be obtained.
[0039]
For example, an inlet pipe and an outlet pipe of a diameter of 80 mm is connected to a valve casing of a diameter of 200 mm and a height of 600 mm, and zircon beads of a diameter of 60 to 120|im are laid with a thickness of 80 mm on the bottom portion of the valve casing as the sealant. Here, in the case of a gate valve in which the valve body lower end can be buried to a depth of 50 mm, the leak rate of the valve can be made 0.005% or less of the valve capacity coefficient (Cv value). In a case where the aspiration is performed in the opened state of this valve at a flow rate of 50 m /h, the sealant dispersion mass flow rate can be made 70 g/h. [0040]
Furthermore, the driving device of the valve may be an air cylinder, and the driving force at the time of valve closure can be obtained from the supplied air pressure to the air cylinder during the valve closure action. Regarding the driving force when air of a pressure of 0.001 MPa is supplied into the valve casing 1 from the fluidized bed gas piping

28 11 as the fluidized bed gas, by performing the valve closure operation under different
driving force conditions, the minimum driving force necessary for valve closure (required
driving force for valve closure) can be obtained. For example, in the case of the valve
mentioned above, the required driving force for valve closure can be made 10 N or less.
[0041]
(Seventh Embodiment)
By adopting entirely the same conditions as the sixth embodiment, except for loading an alumina fiber ring-shaped pad of a thickness of 40 mm on the sealant with the same method as FIG. 7 and FIG. 8, the leak rate of the valve can be made a Cv value of 0.005% or less, and the sealant dispersion mass flow rate in a case where aspiration is performed in the opened state at a flow rate of 50 m /h, can be made 25 g/h. [0042] (Eighth Embodiment)
By adopting entirely the same conditions as the seventh embodiment, except for using zircon,beads of a diameter of 120 f^m to 400 4im.,as..the sealant, the leak rate of.the. valve can be made a Cv value of 0.1% or less, and the sealant dispersion mass flow rate in a case where aspiration is performed in the opened state at a flow rate of 50 m^/h, can be made 1 g/h. [0043] (Valve casing)
When a fluidized bed gas of an appropriate pressure is supplied from the bottom portion 1 A, 21A and 31A of the valve casing 1,21 and 31 to the interior of the valve casing 1,21 and 31, the sealant 5 acts as a fluidized bed. Furthermore, regarding the fluidized bed applied in the present embodiment, as disclosed in Non-Patent Document 1 mentioned above, standard design methods have been established. That is to say, regarding the setting

29 of; the diameter and the height of the valve casing, the particle size of the sealant, the
thickness of the sealant layer, the gas supply pressure and flow rate, the construction of the
dispersion plate, and the like, they can be appropriately designed based on standard design
methods in the manner disclosed in Non-Patent Document 1. The diameter of the valve
casing 1,21 and 31 can be for example 100 mm or more and 1 m or less. The height of the
valve casing 1 can be for example 100 mm or more and 4 m or less. The layer thickness of
the sealant 5 can be for example 30 mm or more and 1 m or less. The aperture diameter of
the high-temperature gas inlet pipe 3,23 and 33 and the high-temperature gas outlet pipe 4,
24 and 34 within the valve casing 1,21 and 31 can be for example 10 mm or more and 300
mm or less. Furthermore, punched metal or a metallic mesh can be used for the dispersion
plate 6. The fluidized bed gas may be supplied using a generic grid tube or a porous cap
instead of the dispersion plate 6.
[0044]
It is preferable for the fluidization configuration of the fluidized bed of the
sealant 5 to be designed such that it becomes uniform fluidization. However it may be
bubbling fluidization to the extent that slagging does not occur. The purpose of
fluidization of the sealant 5 in the present embodiment is simply to reduce the resistance of
the sealant 5, and the fluidization may be minimal. That is to say, it is acceptable if the
flow rate of the supplied fluidized bed gas is set to a flow speed slightly greater than the
minimum fluidization flow speed unique to the selected sealant 5. In a case where the
fluidized bed gas flow rate is set in this manner, for example the thickness when the
fluidized bed gas is blowing in (maximum thickness of the fluidized bed) is maintained at
less than 2 times that when it is stationary. If the gas flow rate supplied to the valve casing
1,21 and 31 is far greater than the flow rate corresponding to the minimum fluidization
flow speed, a portion of the fluidized sealant 5 is discharged into the high-temperature gas

30 outlet pipe 4,24 and 34 and the high-temperature gas inlet pipe 3,23 and 33. Hence this is
undesirable. The aperture 3A, 23A and 33A of the high-temperature gas inlet pipe 3,23
and 33 and the aperture 4A, 24A and 34A of the high-temperature gas outlet pipe 4,24 and
34 within the valve casing 1,21 and 31 should be arranged at a location higher than the
upper end position reached by the sealant 5 at the time the sealant 5 is fluidized (maximum
thickness of the fluidized bed).
[0045]
(Valve Body Raising and Lowering Device)
In a case where the valve body raising and lowering device 8 is arranged outside the furnace (above the furnace wall 16 of the furnace), a commercial actuator capable of raising and lowering movement can be utilized. For example, an air cylinder, a hydraulic cylinder, a rack and pinion propulsion unit, a ball screw drive unit, or a linear motor can be used. The device may be miniaturized by using a heat resistant actuator for the valve body raising and lowering device 8, and installing this inside the furnace. The method for . adjusting the raising and lowering position of the valve body 2, 22 and 32 may be performed manually, or may be automatically controlled by providing a separate distance meter or load meter, and a control device. The stroke of the valve body raising and lowering device 8 may be for example 50 mm or more and 2 m or less. [0046] (Heating Device)
The heating device 13 for heating the fluidized bed gas is a device for preheating the fluidized bed gas in order to prevent cooling of the valve by the fluidized bed gas, and is selectively installed. The heating device 13 may be a generic fuel gas combustion type heat exchanger, or the gas may be heated by simply setting the fluidized bed gas piping

31 channel longer so that the gas is heated by the heat input to the pipeline from the furnace
body.
[0047]
(Material Properties of Structural Material of Gate Valve)
Provided that the device arranged within the furnace has the required strength, rigidity, and durability in an environment from room temperature to a high temperature of approximately 850°C or 900°C, then any device can be utilized. For example, for the bellows 14, which is a deforming component, metals, such as heat resistant stainless steel, heat resistant cobalt alloy, or heat resistant nickel alloy, such as Inconel or Hastelloy, or heat resistant ceramic fibers having flexibility, such as tyranno fiber, can be used. With regard to components other than the bellows 14, in addition to the materials mentioned above, graphite, a carbon fiber reinforced carbon composite material, alumina, calcia, magnesia, silicon carbide, fused quartz, muUite, zirconia, Portland cement, alumina cement, silicon nitride, or the like, can be used. In a case where materials with a low resistance to oxidation, such as graphite, are used for the members that constitute the... ._ , high-temperature furnace gas gate valve, by maintaining the interior of the furnace as a non-oxidative atmosphere, such as a nitrogen atmosphere, then these qualities of materials can be applied. [0048]
Since there are no special restrictions with respect to the devices installed outside of the furnace, commercial devices with standard quality of materials can be used. [0049] (Sealant)
Provided that the sealant is a granular material that, from room temperature to a high temperature of approximately 850°C or approximately 900°C, has a strength that can

32 endure fluidization, and in which chemical reactions with the working gas, or thermal
decomposition, phase changes, substantial sintering, and phase transformations of itself do
not occur, then any material can be used. For example, fused quartz, alumina, calcia,
magnesia, zircon, stabilized zirconia, titanium oxide, silicon nitride, or silicon carbide can
be used. In particular, when the gate valve is utilized at a temperature of 800°C or higher,
it is preferable to use alumina, magnesia, zircon, stabilized zirconia, titanium oxide, silicon
nitride, or silicon carbide from the viewpoint of particle stability.
[0050]
It is preferable for the particle size of the sealant to be a diameter of 10 |j,m or more and 1 mm or less, and more preferably 40 ^m or more and 500 fim or less. Furthermore, it is particularly preferable for the average particle size to be a diameter of 100 |j,m or more and 300 p,m or less. If the particle size is smaller than a diameter of 10 [im, the surface force on the particles is excessive, and hence even if the gas is supplied from the bottom portion of the fluidized bed, the entire sealant layer cannot be fluidized.
.. Furthermore, if the .particle size is larger than a diameter of 1 mm, although the sealant 5
will be fluidized if the fluidized bed gas supply flow rate is increased, giant bubbles are generated within the fluidized bed of the sealant, which burst at the fluidized bed surface of the sealant. A problem occurs in that the sealant stirred up by this bursting is discharged downstream, and hence this is undesirable. It is preferable for the shape of the sealant to be spherical.
The "particles with little physical property changes" mentioned above is primarily a granular material in which the sealant, from room temperature to a high temperature of approximately 850°C or approximately 900°C, has a strength that can endure fluidization, and in which chemical reactions with the working gas, or thermal decomposition, phase changes, substantial sintering, and phase transformations of itself do

33 not occur, and indicates particles (clusters) in a state where carbonaceous materials (solid
state and liquid state) originating from a working gas, such as a COG, are mixed therein.
For example, if carbonaceous materials such as tar, are deposited on particles that, from
room temperature to a high temperature of approximately 850°C or approximately 900°C,
have a strength that can endure fluidization, and in which chemical reactions with the
working gas, or thermal decomposition, phase changes, substantial sintering, and phase
transformations of itself do not occur, the physical properties of these particles are
expected to slightly change. However, if a granular material that from room temperature
to a high temperature of approximately 850°C or approximately 900°C, has a strength that
can endure fluidization, and chemical reactions with the working gas, or thermal
decomposition, phase changes, substantial sintering, and phase transformations of itself do
not occur, accounts for the majority of the mass of the sealant, the sealant at this time
essentially has, from room temperature to a high temperature of approximately 850°C or
approximately 900°C, a strength that can endure fluidization. Furthermore, with regard to
... the sealant, chemical reactions .with the working gas, or thermal decomposition,, phase
changes, substantial sintering, and phase transformations of itself do not occur, that is to
say, it can be the that it is a granular material with little physical property changes. In the
first and the second aspects of the invention, it is not necessary to specially consider
whether or not such contaminants are present within the sealant. However in the third
aspect of the invention, there is a characteristic in the point that the carbonaceous materials
mixed within the sealant and that themselves form a type of sealant, are combusted and
removed. Therefore the presence of such contaminants in the sealant becomes a
prerequisite.
[0051]

34 With regard to these sealants, a commercial sealant may be used, or a chemically
synthesized sealant may be used.
[0052]
(Fluidized bed gas)
Provided that the fluidized bed gas that fluidizes the sealant is a gas that does not corrode and contaminate the device or the sealant, and has a material property in which a strong reaction does not occur with the working gas, then any gas can be used. For example, a gas such as nitrogen, carbon dioxide, helium, argon, methane, natioral gas, LPG, or dry COG can be used. [0053]
As the fluidized bed gas that can combust the carbonaceous materials, provided it can gasify the carbonaceous materials by reacting with the carbonaceous materials, and does not corrode the device or the sealant, then any material can be used. For example, air, oxygen, water vapor, and the like, can be used.
.[0054] - . ...-, ;.. . . .^ .
(Pad)
The pad is preferably a substance that is stable in the usage temperature range of the valve, and is lightweight such that the flow of the sealant is not hindered, and porous or fibrous ceramics can be used for example. As the ceramic, alumina, silicon carbide, and the like, can be used with respect to a wide range of working gas types. In a case where a non-oxidative working gas is made a prerequisite, carbon can also be used. [0055]
From the viewpoint of not being easily moved by the air flow within the valve casing, it is desirable for the pad to be thick. On the other hand, if the pad is thick, there is

35 a problem in that the valve becomes larger. Consequently, for the thickness of the pad, a
range from 2 mm to approximately 500 mm is preferable.
[0056]
(High-Temperature Working Gas)
The working gas (high-temperature gas) used in the present embodiment is not limited to the wet COG described to this point. The invention is applicable to all gas types such as zinc vapor or petroleum gas containing heavy fuel oil for example, in which the contamination or the corrosion of the valve seat or the valve body as a result of the gas components becomes a problem, and in which it is necessary to continuously maintain the temperature from room temperature to a high temperature of 850°C. [0057]
The foregoing has described in detail the preferred embodiments of the present invention with reference to the attached drawings. However the present invention is not limited to these examples. It will be clear to those having conventional knowledge of the technical field to which the present invention belongs, that various modifications and =. revisions can be considered within the scope of the technical ideas disclosed in the claims, and naturally these also are considered to belong to the technical scope of the present invention.
For example, the sealant was fluidized by the fluidized bed gas supply switching mechanism S. However instead of this, the valve body 2 may stir the sealant 5 by an opening and closing action of the gate valve 100, 200, 300. [0058]
Furthermore, it is preferable for the majority of the component members of the gate valve, for example the valve casing 1, the valve body 2, the inlet pipe 3, the outlet pipe 4, the fluidized bed gas piping 11, and the heating device 13, to be arranged within the

36 fiimace. Consequently, the temperature difference between the components of the gate
valve can be reduced. In the conventional technology, in valves that flow through a
high-temperature gas, the inside of the valve which is the contact area with the
high-temperature gas, is maintained at a high temperature, and by maintaining the outside
of the valve at a low temperature, the strength and the operability of the valve is ensured.
With such a design as a prerequisite, if a heating device is not provided for the valve, the
high-temperature gas that passes through the interior of the valve is cooled by the valve.
Consequently, for example at the time wet COG is flowed through, there is a problem in
that tar is precipitated on the valve inner surfaces. Furthermore, a method is also
considered for avoiding heat extraction from the high-temperature gas passing through the
interior of the valve by providing a heating device on the inside of the valve. In this case,
the temperatiire difference between the inside and the outside of the valve is large.
Therefore it is difficult to control the inside of the valve at a uniform and a constant
temperature. Furthermore, in these valves of the conventional technology, a large
. temperature difference is applied between the components of the valve. Therefore in a
case where the valve is utilized at a high temperature such as 850°C, a problem occurs in
that a large thermal stress is generated, and the lifetime of the valve is markedly reduced.
By arranging the gate valve within the fiamace which is maintained at virtually the same
temperature as the high-temperature gas (gas) passing through the interior of the valve, the
temperature of the entire gate valve can be maintained uniformly and constantly.
Consequently, the problems in the conventional technology mentioned above can be
avoided.
[Brief Description of the Reference Symbols]
[0059]
100, 200, 300 High-temperature fiimace gas gate valve (gate valve)

37 1,21,31 Valve casing
2, 22, 32 Valve body
3, 23, 33 High-temperature gas inlet pipe (first duct)
4, 24, 34 High-temperature gas outlet pipe (second duct)
5 Sealant
5A Sealant surface
6 Dispersion plate
8 Valve body raising and low^ering device
10 Fluidized bed gas inlet
11 Fluidized bed gas piping
12 Fluidized bed gas valve

19 First space on inlet pipe side
20 Second space on outlet pipe side 121 Pad
. .■..•■122 Fan . . .■,:.,.■..,...x...... ..... : ._.
123 Filter
124 Furnace
125 Flowmeter
126 Pressure gauge
S Fluidized bed gas supply switching mechanism

38 CLAIMS
1. A gate valve comprising:
a granular sealant that is made to flow in a temperature range from room temperature to 900°C;
a valve casing wherein the sealant is stored at a bottom portion thereof;
a first duct which is connected to the valve casing and through which a gas flows in from the outside toward the inside of the valve casing;
a second duct which is connected to the valve casing and through which the gas flows out from the inside toward the outside of the valve casing;
a valve body which lowers down to a valve body lowering position where the
valve body is at least partially buried in the sealant and blocks the flow of the gas from the
first duct toward the second duct, and rises to a valve body rising position where the valve
body is arranged above a surface of the sealant and allows the gas to flow in from the first
. duct toward the second duct; and ,.,../.
a valve body raising and lowering device that raises and lowers the valve body between the valve body lowering position and the valve body rising position.
2. The gate valve according to claim 1, frirther comprising;
a fluidized bed gas supply switching mechanism that has fluidized bed gas piping which supplies a fluidized bed gas from the exterior of the valve casing to an interior to fluidize the sealant,
and the fluidized bed gas supply switching mechanism sv^tches the flow of the fluidized bed gas, so that the fluidized bed gas is supplied to an interior of the valve casing through the fluidized bed gas piping during a movement period in which the valve body

39 moves between the valve body lowering position and the valve body rising position, and
the fluidized bed gas is not supplied to the interior of the valve casing in periods other than
the movement period.
3. A gate valve for the inside of a high temperature furnace comprising:
a valve casing which includes at least a fluidized bed that is made to flow a granular sealant that has little physical property change over a temperature range from room temperature to a high temperature of 900°C;
a high-temperature gas outlet pipe connected to the valve casing above a surface of the fluidized bed;
a high-temperature gas inlet pipe connected to the valve casing such that, at least in an opened state of the valve, the aperture is arranged above the surface of the fluidized bed;
a valve body that, in a closed state of the gate valve, is arranged at a valve body lowering position, which is a position in which the valve body is at least partially buried in the sealant such that the flow-through of high-temperature gas between the high-temperature gas inlet pipe and the high-temperature gas outlet pipe is blocked using the sealant, and in an opened state of the gate valve, is arranged at a valve body rising position, which is a position in which the entire valve body is present above the surface of the sealant;
a valve body raising and lowering device that changes the arrangement of the valve body between the valve body lowering position and the valve body rising position;
a fluidized bed gas piping that is connected to a lower portion of, or below, the sealant, for supplying fluidized bed gas which combusts carbide mixed into the sealant, to the valve casing; and

40 a fluidized bed gas switching mechanism that switches the gas that combusts the
carbide, to a supplying state or a stopped state.
4. The gate valve according to claim 1 or 2, wherein
when the valve body is lowered to the valve body lowering position, a space of an interior of the housing is divided into a first space which includes an interior of the valve body, and a second space which is a remaining space.
5. The gate valve according to claim 1 or 2, wherein
when the valve body is lowered to the valve body lowering position, the sealant which has been pushed out by the valve body, divides a space of the periphery of the valve casing into a first space which includes an interior of the first duct, and a second space which includes an interior of the second duct.
6. The gate valve according to any one of claims 1 to 5, wherein a pad that inhibits dispersal of the sealant is loaded on an upper surface of the sealant.
7. The gate valve for the inside of the high temperature furnace according to any one of claims 2 to 5, wherein the fluidized bed gas is an oxidative gas that contains oxygen.
8. The gate valve for the inside of the high temperature furnace according to any one of claim 1 through claim 5, wherein the sealant is composed of one type, or two or more types, selected from alumina, magnesia, zirconia, stabilized zircon, titanium oxide, silicon nitride, and silicon carbide.