JP2976172B2 - Gas shut-off valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shut-off valve which can shut off a gas even when particles are attached.

[0002]

2. Description of the Related Art In the production of silicon semiconductor wafers, as is well known, polycrystalline silicon is produced, and then the polycrystalline silicon is monocrystallized to produce a monocrystalline silicon ingot. In the production of polycrystalline silicon, silicon is generally precipitated in the form of a rod to produce rod-shaped polycrystalline silicon. In recent years, however, silicon has been precipitated in the form of particles, for example, silicon particles having a diameter of about 1 to 1.5 mm. Producing bodies has been proposed and put into practical use. In the production of such silicon particles, silicon particles are caused to flow through a flow line together with a gas such as a monosilane gas. As disclosed in US Pat. Nos. 5,202,099 and 5,205,998 and the drawings,
In order to shut off the flow of silicon particles and gas, if necessary, a particle shutoff valve utilizing a phenomenon in which particles stay at an angle of repose on a specific surface is provided, and such a particle shutoff valve is provided. One or two or more gas shut-off valves are disposed downstream of.

[0003]

As a gas shut-off valve disposed in the flow line, a known shut-off valve for selectively shutting off gas by the cooperation of a valve seat member and a valve member is used. When used, the following problems have been found to occur. That is, when the flow of the particles and the gas is shut off in the flow line, the flow of the particles is first shut off by operating the particle shutoff valve, and thereafter, the flow is disposed downstream of the particle shutoff valve. Activate the gas shutoff valve to shut off the gas. Since the particulate shutoff valve is operated upstream of the gas shutoff valve prior to the activation of the gas shutoff valve, a large amount of particles do not flow into the gas shutoff valve when the gas shutoff valve is activated. However, it is not possible to eliminate substantially any particles present in the gas shut-off valve when the gas shut-off valve is activated, and there are some particles present in the gas shut-off valve. If the granular material is interposed between the valve seat member and the valve member which are brought into close contact with each other, the close contact between the valve seat member and the valve member becomes insufficient, and the shutoff of the gas becomes insufficient. It becomes something. In addition, the granular material is damaged due to the granular material being caught between the valve seat member and the valve member, and the valve seat member and the valve member are worn in a relatively short time. Will not work as required.

The present invention has been made in view of the above-mentioned facts, and a technical problem of the present invention is that it is possible to sufficiently shut off gas even when particles are attached to the gas, and also to prevent gas from being blocked. It is an object of the present invention to provide an improved gas shut-off valve in which the wear of the valve seat member and the valve member is prevented as much as possible with the accompanying damage of the granular material.

[0005]

In order to achieve the above technical object, according to the present invention, an upstream annular seal portion and a downstream annular seal portion are formed on one of a valve seat member and a valve member. Gas injection means for injecting gas into the valve housing is provided between the upstream annular seal portion and the downstream annular seal portion when the valve member is moved to the shut-off position.

That is, according to the present invention, as a gas shut-off valve for achieving the above technical object, a valve housing in which an introduction passage and an outlet passage are provided, and the introduction passage and the outlet passage in the valve housing. Shutoff means for selectively shutting off communication with the road, the shutoff means comprising a stationary annular valve seat member,
A movable valve member that can be moved between a shut-off position and a non-cut-off position, and gas injection means, and one of the valve seat member and the valve member has an upstream annular seal portion and a downstream annular member. A gas shut-off valve, wherein the gas injection means injects gas into the valve housing between the upstream annular seal and the downstream annular seal. Provided.

Preferably, when the valve member is moved from the non-blocking position to the blocking position, the other of the valve member and the valve seat member is first brought into close contact with the upstream annular seal portion, Thereafter, it is brought into close contact with the downstream annular seal portion. It is preferable that the upstream side annular seal portion and the downstream side annular seal portion are formed on the valve seat member. Preferably, the gas injection means includes a plurality of injection holes opened on the inner peripheral surface of the valve seat member, and gas is injected from the injection holes into the valve housing. The introduction passage is disposed at an upper end portion of the valve housing, and when the valve member is located at the shut-off position, the valve member is opposed to and below the inflow opening located at the lower end of the introduction passage. And the valve member is advantageously retracted laterally with respect to the inlet opening when the valve member is in the non-blocking position.

[0008]

In the gas shut-off valve of the present invention, when the valve seat member and the valve member cooperate, the upstream annular seal portion and the downstream annular seal formed on one of the valve seat member and the valve member. Gas injection means injects gas into the valve housing between the first and second portions. Therefore, when the other of the valve seat member and the valve member is brought into close contact with the upstream annular seal portion and the downstream annular seal portion formed on one of the valve seat member and the valve member, the gas is injected from the gas injection means. The residual gas is removed from the space between the other of the valve seat member and the valve member and the upstream annular seal portion and the downstream annular seal portion by the gas. Thus, the other of the valve seat member and the valve member and the upstream-side annular seal portion and the downstream-side annular seal portion are brought into close contact with substantially no intervening granular material therebetween, thereby ensuring gas shutoff. . The interposition of particles between the other of the valve seat member and the valve member and the upstream annular seal portion and the downstream annular seal portion is sufficiently suppressed, and the valve seat is damaged together with the damage of the particles accompanying the gas. Wear of the member and the valve member is prevented as much as possible.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a preferred embodiment of a particulate shutoff valve according to the present invention.

FIG. 1 illustrates a preferred embodiment of a gas shut-off valve constructed in accordance with the present invention. The illustrated gas shut-off valve, which is preferably used as a gas shut-off valve in a polycrystalline silicon particle manufacturing plant, includes a valve housing indicated by reference numeral 2 as a whole, and the valve housing 2 includes an upper housing member 4 and a lower housing member. 6 is comprised. The upper housing 4, which can be formed from a suitable metal material such as carbon steel or stainless steel, has a main portion 8 having a substantially frustoconical cylindrical shape whose lower surface is entirely open. An annular connecting flange 10 is formed at a lower end of the main part 8. A shallow annular recess 12 for lining is formed on the outer surface of the connecting flange 10, that is, on the inner peripheral edge of the lower surface. A cylindrical projection 14 extending upward is formed at an upper end of the main portion 8, and an annular connecting flange 16 is formed at an upper end of the cylindrical projection 14. Cylindrical projection 14
The inner peripheral surface has a relatively large diameter upper part 18 and a relatively small diameter lower part 2.
0, an annular shoulder surface 22 facing upward is formed on the inner peripheral surface of the cylindrical projection 14. A shallow concave portion 24 for lining is formed on the outer surface of the connecting flange 16, that is, on the inner peripheral edge of the upper surface. An annular recess 25 for accommodating a sealing O-ring (not shown) is also formed on the upper surface of the connection flange 16.
In the main portion 8 of the upper housing member 4, a relatively small-diameter purge gas introduction cylindrical protrusion 26 extending leftward is formed on the left side in FIG. 1.
An annular connecting flange 28 is formed at the tip of the. As can be clearly understood from FIG. 1, the inner surface of the upper housing 2 as described above (except for the portion where the valve seat member described later is disposed, the recess 1 in the connecting flanges 10 and 16).
2 and 24 and the outer periphery of the connecting flange 28 (including the inner peripheral edge on the left side) are provided with a lining 32 preferably made of a fluororesin such as polytetrafluoroethylene.

Referring to FIG. 2 together with FIG. 1, a cylindrical introduction member 34 is mounted on the cylindrical protrusion 14 formed at the upper end of the main portion 8 of the upper housing member 4. As will be further described later, the polycrystalline silicon particles are caused to flow together with the gas containing the monosilane gas through the cylindrical introduction member 34, and such silicon particles are extremely high in purity and may be contaminated by contact with substances other than silicon. Is desired to be avoided. Therefore, the tubular introduction member 34 is advantageously formed from annealed polycrystalline silicon. The tubular introduction member 34 has a cylindrical upper portion 36 having a relatively large outer diameter, a cylindrical intermediate portion 38 having a relatively small outer diameter, and a frustoconical cylindrical shape whose outer diameter is gradually reduced downward. Has a lower part 40,
An annular shoulder surface 4 facing downward is provided on the outer peripheral surface of the cylindrical introduction member 34.
2 are formed. The outer diameter of the upper part 36 of the cylindrical introduction member 34 is made to correspond to the inner diameter of the upper part 18 of the cylindrical projection part 14, and the outer diameter of the intermediate part 38 of the cylindrical introduction member 34 is lower than the lower part 20 of the cylindrical projection part 14. It corresponds to the inside diameter of. As shown in FIG. 1, the cylindrical introduction member 34 is inserted into the cylindrical protrusion 14 of the upper housing member 4 from above, and a shoulder surface 42 formed on the outer peripheral surface thereof.
A shoulder surface 22 formed on the inner peripheral surface of the cylindrical protrusion 14.
, So that it is supported at the required mounting position. The frustoconical cylindrical lower part 40 of the cylindrical introduction member 34 is projected downward into the upper housing 4 beyond the lower end of the cylindrical projection 14. The tapered inclination angle α on the outer peripheral surface of the truncated conical cylindrical lower portion 40 may be about 10 to 30 degrees. The tubular introduction member 34 is formed with an introduction passage 44 extending therethrough, and an inflow opening 46 is defined at a lower end thereof. The cross-sectional shape of the introduction path 44 and the shape of the inflow opening 46 may be circular. The lower end of the introduction path 44 is formed in a truncated cone shape whose inner diameter gradually increases downward. Conveniently, as shown in FIG. 1, the introduction channel 44 extends substantially vertically and the inflow opening 46 is positioned substantially horizontally.

Continuing with FIG. 1, the lower housing member 6 of the valve housing 2 is also connected to the upper housing member 4.
Similarly, it can be formed from an appropriate metal material such as carbon steel or stainless steel. The lower housing member 6 has a truncated-cone-shaped main portion 48 whose outer diameter and inner diameter are gradually reduced downward, and the upper surface thereof is entirely open. An annular connecting flange 50 is formed at the upper end of the lower housing member 6. On the outer surface of the connecting flange 50, that is, on the inner peripheral edge of the upper surface, a shallow concave portion 52 for lining is formed. Further, an annular concave portion 56 for accommodating the sealing O-ring 54 is formed on the upper surface of the connecting flange 50. At the lower end of the lower housing member 6, a cylindrical projection 58 extending downward is formed,
An annular connecting flange 60 is provided at the lower end of the cylindrical projection 58.
Are formed. The inner peripheral surface of the cylindrical protrusion 58 is defined by an upper portion 62 having a relatively large diameter and a lower portion 64 having a relatively small diameter, and the inner peripheral surface of the cylindrical protrusion 58 has an annular shoulder surface 66 facing downward. Are formed. The inner surface of the lower housing member 6 (including the concave portion 52 of the connecting flange 50 and the outer surface of the connecting flange 60, that is, the inner peripheral edge of the lower surface) is also made of a fluororesin similarly to the inner surface of the upper housing member 4. A lining 68 is provided which is convenient.

A cylindrical lead-out member 70 is mounted on the cylindrical protrusion 58 of the lower housing member 6. This tubular lead-out member 70 is, similarly to the tubular lead-in member 34 in the upper housing member 4, advantageously formed of polycrystalline silicon that has been annealed to avoid contamination of silicon particles. . The tubular lead-out member 70 has an upper portion 72 having a relatively large outer diameter and a lower portion 74 having a relatively small outer diameter, and an annular shoulder surface 76 facing downward is formed on the outer peripheral surface of the tubular lead-out member 70. ing. Cylindrical lead-out member 7
An annular ridge 78 protruding upward is formed on the inner peripheral edge of the upper end surface of the ridge.
Are formed. The outer diameter of the upper portion 72 of the cylindrical protruding member 70 is made to correspond to the inner diameter of the upper portion 62 of the cylindrical protruding portion 58, and the outer diameter of the lower portion 74 of the cylindrical protruding member 70 is smaller than that of the lower portion 64 of the cylindrical protruding portion 58. Corresponds to the inner diameter.
The cylindrical lead-out member 70 is inserted into the cylindrical protrusion 58 of the lower housing member 6 from above, and a shoulder surface 78 formed on the outer peripheral surface is formed on the inner peripheral surface of the cylindrical protrusion 58. By being brought into contact with the shoulder surface 66 which is provided, it is supported at a required mounting position. A lead-out passage 80 extending substantially vertically is formed in the tubular lead-out member 70. Outgoing path 80
Has a circular cross-section, the inner diameter of which is gradually reduced downward in the upper half, and the inner diameter is maintained unchanged in the lower half. As will be described in more detail later, the silicon particles flowing into the valve housing 2 from the introduction path 44 provided in the upper housing member 4 together with the gas containing the monosilane gas before the lower housing 80 There is a possibility of collision or contact with the inner surface of the member 6. In view of this fact, on the inner surface of the lower housing member 6, in addition to the lining 68, a plurality of protective members 82, which are conveniently formed of annealed polycrystalline silicon, are provided. ing. Main part 4 of lower housing member 6
Protective members 8 arranged circumferentially along the inner surface of 8
2 has a truncated cone shape corresponding to the inner surface of the main portion 48 of the lower housing member 6 as a whole, and a projection 84 is formed on the outer edge of the lower end surface of the protection member 82. Each of the protection members 82 is inserted into the lower housing member 6 from above, and a lower end surface thereof is brought into contact with an upper end surface of the tubular lead-out member 70. More specifically, a protrusion 84 formed on the lower end surface is provided. Is opposed to an annular ridge 78 formed on the upper end surface of the tubular lead-out member 70 and positioned radially outward, and the lower end surface thereof is brought into contact with the upper end surface of the tubular lead-out member 70 by , Supported at the required mounting position. As is clearly shown in FIG.
Cooperate to define a truncated cone shape whose inner diameter is gradually reduced downward, and the truncated cone shape is the upper half of the lead-out passage 80 formed in the tubular lead-out member 70. Smoothly follows the truncated cone shape in.

The upper housing member 4 and the lower housing member 6 are arranged at the lower end of the upper housing member 4 and the upper end of the lower housing member 6 as clearly shown in FIG. The connecting flanges 50 are aligned and connected to each other. In this connection, the shaft of the bolt 86 is inserted into holes formed in the connection flanges 10 and 50 at a plurality of positions spaced apart in the circumferential direction, and a nut 88 is screwed onto the protruding end of the shaft of the bolt 86. This is accomplished by dressing up.

Referring to FIGS. 1 and 2, a shut-off means 90 for selectively shutting off the communication between the introduction passage 44 and the exit passage 80 is provided in the valve housing 2. The shut-off means 90 includes a stationary annular valve seat member 92 and a movable valve member 94. The valve seat member 92 is preferably formed of a fluorine-based resin such as polytetrafluoroethylene, is generally annular, and has a substantially rectangular cross-sectional shape. The valve seat member 92 is substantially horizontal to the upper housing member 4 by allowing the valve seat member 92 to penetrate at a plurality of circumferentially spaced positions at a required position at the upper end of the main portion 8 of the upper housing member 4. It is secured by screwing a set screw 96, which advantageously has a fluororesin coating, to the annular inner surface. It is important that the valve seat member 92 be formed with an upstream annular seal portion 98 and a downstream annular seal portion 100. As clearly shown in FIG. 2, the upstream annular sealing portion 98
The valve seat member 92 is defined by an annular projecting piece that projects radially inward from the upper end of the inner peripheral surface of the main portion and then projects downward. An annular groove is formed on the lower surface of the valve seat member 92 at a certain distance from the inner peripheral edge, and an annular hanging piece defining the downstream annular seal portion 100 is formed on the inner peripheral side of the annular groove. On the outer peripheral surface of the valve seat member 92, a sealing O
An annular recess 104 in which the ring 102 is accommodated is formed. The valve seat member 92 is further provided with gas injection means indicated by reference numeral 110 as a whole. The gas injection means 110 will be described in detail. An annular recess is formed in the upper half of the outer peripheral surface of the valve seat member 92, and the annular recess allows the upper end of the side wall of the main portion 8 of the upper housing member 4 to be connected to the valve seat. An annular ventilation passage 111 is defined between the member and the member 92. The valve seat member 92 further includes a number of injection holes 106 (FIGS. 1 and 2 show only one of them) that extends slightly inward from the annular recess radially inward and downward. ) Is formed. Such an injection hole 1
Reference numerals 06 are arranged uniformly over the entire circumferential direction of the valve seat member 92, and each of the injection holes 106 is formed between the upstream annular seal portion 98 and the downstream annular seal portion 100 formed in the valve seat member 92. An opening is formed on the inner peripheral surface of the valve seat member 92 between them. A through hole 108 is formed at the upper end of the side wall of the main portion 8 of the upper housing member 4, and the downstream end of the through hole 108 is communicated with the annular air passage 111. The upstream end of the through hole 108 is connected to a pressurized gas source 113 via a flexible hose, a feed control valve, or the like (not shown). Such gas injection means 11
0 is a gas, which is conveniently nitrogen gas, is passed through a plurality of injection holes 10 through a through hole 108 and an annular ventilation passage 111.
6 and is injected into the valve housing 2 from the injection hole 106.

The movable valve member 94 in the shut-off means 90
Can be appropriately moved between a blocking position shown by a two-dot chain line in FIG. 1 and a solid line in FIG. 2 and a non-blocking position shown by a solid line in FIG. More specifically, referring to FIG. 3 together with FIGS. 1 and 2, the upper housing member 4 is formed with a bulging portion 112 extending vertically in FIG. 3, and extends through the bulging portion 112. An existing support shaft 114 is rotatably mounted. The support shaft 114 has a pair of bearing members 116 and 118 mounted on the upper housing member 4.
And is displaced laterally (to the right in FIG. 1) from an inflow opening 46 formed at the lower end of the tubular introduction member 34 as clearly understood from FIG. 1, it extends substantially horizontally in a direction perpendicular to the plane of the paper and in a vertical direction in FIG. FIG.
As clearly shown in FIG. 1, a pair of sealing means 115 and 117 are disposed between the inner peripheral surface of the bulging portion 112 and the outer peripheral surface of the support shaft 114. Sealing means 115 and 11
7 includes inner O-rings 119 and 121 and outer O-rings 123 and 125;
Discharge paths 127 and 129 are formed in the bulging portion 112 between the bulging portion 112 and the outer O-rings 123 and 125. If a gas such as monosilane leaks through the inner O-rings 119 and 121, the leaked gas is sent to the abatement apparatus (not shown) via the exhaust passages 127 and 129. A cover 12 is provided on the outer end (lower end in FIG. 3) of the bulging portion 112 of the upper housing member 4.
0 is a suitable fixing means such as a fastening screw (not shown)
Has been fixed by. One end of the support shaft 114 penetrates the cover 120 and extends downward in FIG. 3, and the extension end of the support shaft 114 is connected to an electric motor or an air motor via a speed reducing means 122 which may be a reduction gear train. And the like. The inner surface of the bulging portion 112 exposed in the valve housing 2 is also provided with a lining which may be made of a fluorine resin, and the surface of the support shaft 114 exposed in the valve housing 2 is made of a fluorine resin. Advantageously, a good coating is applied.

One end of a substantially L-shaped support arm 126 is fixed to the support shaft 114 by an appropriate fixing means (not shown) such as screwing or bonding. A substantially disk-shaped support member 128 is attached to the other end of the support arm 126. More specifically, a recess 130 is formed on the lower surface of the other end of the support arm 126 in the state shown in FIG. 2, and a through hole extending from the recess 130 to the upper surface is formed.
Then, the shaft of the fastening bolt 132 is extended through the through hole, and the shaft of the fastening bolt 132 is
The support member 128 is attached to the other end of the support arm 126 by being screwed to the center of the lower surface of the support arm 128. The recess 130 formed in the support arm 126
, A cover member 134 is press-fitted, and the head of the fastening bolt 132 located in the recess 130 is covered with the cover member 134. Conveniently, the support arm 126, support member 128, and cover member 134 are formed from a fluorinated resin such as polytetrafluoroethylene. If desired, the support arm 126, support member 128, and cover member 134 can be formed from other suitable members, such as steel, and can be coated with a fluorocarbon resin. The valve member 94 is mounted on a support member 128. The valve member 94 itself can also be formed from a fluorine-based resin such as polytetrafluoroethylene. As will be apparent from the description below, the surface of the valve member 94 is slightly contacted with polycrystalline silicon particles, and if desired, is annealed to avoid contamination of the silicon particles contacted with it. The valve member 94 can also be formed from the treated polycrystalline silicon. A circular concave portion 136 having an inner diameter slightly larger than the outer diameter of the support member 128 is formed on the back surface of the valve member 94 which has a disk shape as a whole, and the support member 128 is screwed into the concave portion 136, that is, the concave portion. The support member 1 is attached to a female thread formed on the inner peripheral surface of the 136.
The valve member 94 is mounted on the support member 128 by screwing and mounting a male thread formed on the outer peripheral surface of the support member 128. The upper surface of the valve member 94 is advantageously formed with a recess 138, which is advantageously spherical. It is important that the shape of the upper peripheral edge or side surface of the valve member 94 is set so as to act on the valve seat member 92 as follows. That is, when the valve member 94 is moved from the non-blocking position shown by the solid line in FIG. 1 to the blocking position shown by the solid line in FIG. 2 and shown by the two-dot chain line in FIG. When the valve member 94 is moved to the position indicated by the two-dot chain line 94A in FIG. 2, the valve member 94 is moved to the upstream side annular seal portion 9 of the valve seat member 92.
Closer to 8. At this point, the valve member 9
4 is still slightly separated from the downstream annular seal portion 100 of the valve seat member 92. Next, the valve member 94
2 is moved to the shut-off position shown by the solid line in FIG. 2 and by the two-dot chain line in FIG. 1, as can be clearly understood from FIG. 2, the valve member 94 is connected to the downstream annular seal portion 1 of the valve seat member 92.
00, so that a cut-off between the inlet path 44 and the outlet path 80 is ensured.

By appropriately rotating the support shaft 114 by the drive source 124, the valve member 94 is moved to the position shown in FIG.
2 is moved between a blocking position shown by a two-dot chain line and a solid line in FIG. 2 and a non-blocking position shown by a solid line in FIG. If desired, a blocking position restriction piece and a non-blocking position restriction piece acting on the support shaft 114 or the support arm 126 (not shown)
Can be provided so that the valve member 94 can be positioned with sufficient precision in the shut-off position and the non-cut-off position. As will be clearly understood with reference to FIGS. 1 and 2, when the valve member 94 is positioned in the shut-off position,
The valve member 94 is brought into close contact with the upstream annular seal portion 98 and the downstream annular seal portion 100 of the valve seat member 92, and a concave portion 138 formed on the upper surface of the valve member 94 is provided.
Inflow opening 46 defined at the lower end of tubular introduction member 34
, Below and preferably substantially concentrically. On the other hand, as clearly understood from FIG.
4 is positioned at the non-blocking position, the valve member 94
Retreats laterally with respect to the inflow opening 46.

In the above-described embodiment, the upstream-side annular seal portion 98 and the downstream-side annular seal portion 100 are formed in the valve seat member 92.
When the valve member 94 is formed with an upstream-side annular seal portion and a downstream-side annular seal portion in an appropriate form, the valve member 94 is first moved when the valve member 94 is moved from the non-blocking position to the blocking position. The upstream annular seal portion of the member 94 can be made to be in close contact with the valve seat member 92, and then the downstream annular seal portion of the valve member 94 can be made to be in close contact with the valve seat member 92.

The gas shut-off valve as described above is suitably used as a gas shut-off valve in a plant for producing polycrystalline silicon particles. In this case, as shown by a two-dot chain line in FIG.
The upper end of the valve housing 2 is connected to a pipe member 140 (a lining made of a fluorine-based resin and a protection member made of polycrystalline silicon are also provided on the inner surface of the pipe member). It is connected to a polycrystalline silicon particle deposition means (not shown) via a valve (not shown). In the means for depositing polycrystalline silicon particles, a monosilane gas is used as is well known to those skilled in the art. Therefore, when the particulate shut-off valve is in a non-operating state, that is, in a non-cut-off state, silicon particles are supplied to the gas shut-off valve through the pipe member 140 together with a gas containing monosilane gas. At this time, the valve member 94 of the shut-off means 90 is located at a non-cut-off position indicated by a solid line in FIG. Accordingly, the gas and the silicon particles supplied from the pipe member 140 to the introduction passage 44 flow into the valve housing 2 from the inflow opening 46, flow down the valve housing 2 substantially vertically, and pass through the discharge passage 80. And flows out of the valve housing 2. At the lower end of the valve housing 2, as shown by a two-dot chain line in FIG.
A pipe member 142 (a fluorinated resin lining and a protection member made of polycrystalline silicon are also provided on the inner surface of the pipe member) is connected. The pipe member 142 is substantially the same as the illustrated gas shut-off valve. It is connected, for example, to a collecting vessel (not shown) via a good additional gas shut-off valve (not shown). Accordingly, the gas and the silicon particles are conveyed from the pipe member 142 to the collection container through the additional gas shut-off valve in which the valve member in the shut-off means is located at the non-cut-off position. As can be clearly understood with reference to FIG. 1, when the valve member 94 is in the non-blocking position, the valve member 94 is retracted laterally with respect to the inlet opening 46 so that the inlet Silicon particles flowing into the valve housing 2 from the opening 46 and flowing down the valve housing 2 do not substantially collide with the valve member 94.

When shutting off the flow of gas and silicon particles, first, the above-mentioned particle shut-off valve, which is disposed upstream of the gas shut-off valve, is brought into an operating state, that is, a shut-off state.
The passage of gas is allowed, but the flow of silicon particles is cut off. Therefore, supply of a large amount of silicon particles to the gas shutoff valve through the pipe member 140 is stopped. Thereafter, the gas shut-off valve is shut off, and the additional gas shut-off valve disposed downstream thereof is shut off. When the gas shut-off valve is set to the shut-off state, for example, the valve member 94 of the shut-off means 90 is turned off as shown in FIG.
Are moved from the non-blocking position shown by the solid line to the position shown by the two-dot chain line 94B in FIG. 2 and temporarily stopped. When the valve member 94 is moved to a position indicated by a two-dot chain line 94B in FIG.
Is close to the valve member 94 (however, there is still a slight gap between the upstream annular seal portion 98 and the valve member 94 to such an extent that the silicon particles can pass through). Next, the many injection holes 10 of the gas injection means 110
From 6, gas is injected into the valve housing 2 between the upstream annular seal portion 98 and the downstream annular seal portion 100 of the valve seat member 92. The injection of the gas causes the valve member 9
The attached silicon particles are removed from the upstream annular seal 98 and the downstream annular seal 100 of the valve seat member 4 and the valve seat member 92. At this time, some silicon particles are caused to flow down through the introduction path 44, and the silicon particles are
May be deposited on the concave portion 138. In a preferred embodiment, the valve member 94 is returned to the non-blocking position shown by the solid line in FIG. 1 again, and the silicon particles on the concave portion 138 of the valve member 94 are dropped. Further, the operation of moving the valve member 94 to the position shown by the two-dot chain line 94B in FIG. 2 and then returning it to the non-blocking position shown by the solid line in FIG. 1 is repeated. Thereafter, the valve member 94 is moved toward the shutoff position indicated by the two-dot chain line in FIG. When the valve member 94 is moved to a position indicated by a two-dot chain line 94A in FIG. 2, the upstream annular seal portion 98 of the valve seat member 92 is brought into close contact with the valve member 94. Therefore, the gas injected into the valve housing 2 from the large number of injection holes 106 is prevented from flowing upstream, and is directed intensively to the lower portion of the valve member 94 and the downstream annular seal portion 100 of the valve seat member 92. Thus, residual adhesion of silicon particles in these portions is sufficiently and reliably removed. Next, the valve member 94 is positioned at the shut-off position indicated by the two-dot chain line in FIG. 1 and the solid line in FIG.
Is brought into close contact with the valve member 94 and thus the valve seat member 92.
The gas is shut off sufficiently and reliably by cooperation of the valve member 94 and the valve member 94. Then, the downstream annular seal portion 10 of the valve seat member 92 is provided.
Substantially at the same time as or after 0 is brought into close contact with the valve member 94, the injection of gas from the injection hole 106 is stopped. Up to this point, the injection of gas from the injection hole 106 can be continuously performed. However, if desired, the gas is injected only when the valve member 94 is located closer to the shut-off position than the position indicated by the two-dot chain line 94B in FIG. , In other words, the valve member 94
When is located on the non-blocking position side of the position shown by the two-dot chain line 94B in FIG. 2, the gas injection can be interrupted.

Instead of the operation mode of the valve member 94 as described above, for example, the valve member 94 can be simply continuously moved from a non-blocking position shown by a solid line in FIG. 1 to a blocking position shown by a solid line in FIG. . In this case, the valve member 94 is positioned at a position indicated by a two-dot chain line 94B in FIG.
4A, the gas injection can be started, and the gas injection can be stopped after the valve member 94 reaches the shut-off position indicated by the solid line in FIG. 2 or thereafter. Valve member 9
Even after the shutter 4 has been moved to the shut-off position, some silicon particles may enter the valve housing 2 through the introduction path 44, but such silicon particles are formed on the upper surface of the valve member 94. It is housed in the recess 138.

When the additional gas shut-off valve is shut off substantially simultaneously with or immediately after the gas shut-off valve is shut off, the gas shut-off valve is formed on the upper housing member 4 of the valve housing 2. A purge gas, which may be nitrogen gas, is introduced through an introduction path defined in the projection 26. The purge gas and the gas containing the monosilane gas present in the valve housing 2 are appropriately passed through a discharge passage (not shown) formed in the upper housing 4 and a pipe member (not shown) connected thereto. Abatement equipment (not shown)
Is discharged. When the flow of the gas and the silicon granules is restarted, the additional gas shutoff valve, the gas shutoff valve and the granule shutoff valve may be sequentially opened.

[0024]

According to the gas shut-off valve of the present invention, the gas can be shut off sufficiently reliably even when the gas is accompanied by particles, and in addition, the particles are damaged and the valve member and the valve seat member are damaged. Wear can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a preferred embodiment of a gas shutoff valve configured according to the present invention.

FIG. 2 is an enlarged vertical sectional view showing a part of the gas shut-off valve of FIG.

FIG. 3 is a partial cross-sectional view showing the gas shut-off valve of FIG. 1;

[Explanation of symbols]

 2: valve housing 4: upper housing member 6: lower housing member 44: introduction path 46: inflow opening 80: outlet path 90: shut-off means 92: valve seat member 94: valve member 98: upstream annular seal portion 100: downstream side Annular seal portion 106: injection hole 110: gas injection means

Claims (5)

(57) [Claims] 1. A valve housing having an introduction path and an output path disposed therein, and a shutoff means for selectively shutting off communication between the introduction path and the output path within the valve housing. The shut-off means comprises a stationary annular valve seat member, a movable valve member that can be moved between a shut-off position and a non-cut-off position, and gas injection means. On one side, an upstream-side annular seal portion and a downstream-side annular seal portion are formed, and the gas injection unit supplies gas into the valve housing between the upstream-side annular seal portion and the downstream-side annular seal portion. A gas shut-off valve for injecting. 2. When the valve member is moved from the non-blocking position to the blocking position, the other of the valve member and the valve seat member is first brought into close contact with the upstream annular seal portion,
After that, it is brought into close contact with the downstream side annular seal portion,
The gas shut-off valve according to claim 1. 3. The valve seat member according to claim 1, wherein the upstream annular seal portion and the downstream annular seal portion are formed on the valve seat member.
A gas shut-off valve as described. 4. The gas injection means according to claim 1, wherein said gas injection means includes a plurality of injection holes opened on an inner peripheral surface of said valve seat member, and gas is injected into said valve housing from said injection holes. 3. The gas shut-off valve according to any one of 3). 5. The introduction passage is disposed at an upper end of the valve housing, and when the valve member is located at the shut-off position, the valve member is connected to an inflow opening located at a lower end of the introduction passage. The valve member according to any of the preceding claims, wherein the valve member retreats laterally with respect to the inflow opening when the valve member is positioned opposite to and below the non-blocking position. Gas shut-off valve.