JPS6171832A - Stock material supply apparatus - Google Patents

Abstract

PURPOSE:To stably supply stock gas to a reaction vessel for a long time, by providing a means for supplying gas, which is not reacted with the stock solution filling a stock material tank and used as the nuclei of gas bubbles generated by the boiling of the stock solution, into the stock solution for a long period of time. CONSTITUTION:When the supply of a stock material is started, a stock material tank 1 is heated by a heater 3 to adjust a stock solution 2 to predetermined temp. and the upper space 4 of the stock material tank 1 is filled with stock gas with predetermined pressure equal to or higher than atmospheric pressure. For example, in order to adjust the pressure of the stock gas to 1kg/cm<2>G when the stock solution 2 is SiCl4, the stock solution 2 is heated to 80o. Next, an automatic valve 10 is closed while an automatic valve 7 is opened to send the stock gas to a reaction vessel. The flow amount of the stock gas is con trolled by a flow control apparatus 8. When the supply of the stock gas is finished, the automatic valve 7 is closed and the automatic valve 10 is opened to purge piping 5 with nitrogen gas.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is capable of stably producing liquid raw materials such as SIC14+GeCl4 used in the production of fiber base materials or semiconductors in large quantities and stably while precisely controlling the flow rate. It relates to a raw material supply device that can introduce raw materials into a reaction vessel.

<Prior Art> A case will be described in which the raw material supply device is a manufacturing device for optical fiber base material. The manufacturing method of the base material for the original fiber is VAD.
Law is known as law, external law is law, internal law is law, etc. Among these, in the VAD method, which requires continuous supply of raw material gas for a long period of time, raw material gas obtained by vaporizing liquid glass raw material is sent to a reaction vessel at a pressure higher than atmospheric pressure, and is burned in a hydrogen oxide burner or a plasma burner to form a glass medium. is produced, deposited on a rotating starting member to produce a rod-shaped porous preform, and further this porous preform is spun into an optical fiber. For this reason, a raw material supply device that continuously and stably supplies a large amount of raw material gas to the reaction vessel has become necessary. Similarly, a raw material supply device is used which continuously supplies raw material gas to the reaction vessel, even if it is externally attached or internally sealed. Also in semiconductor processes, similar raw material supply devices that feed raw material gases at pressures above or below atmospheric pressure are widely used. An example of such a raw material supply device is shown in FIG. According to the raw material supply device shown in FIG. 3, an airtight raw material tank 1 contains a raw material liquid 2 that reacts with oxygen or moisture in the atmosphere, and the outer periphery of the raw material tank 1 is used to vaporize the raw material tL2. A heater 3 is installed. The upper space 4 of the raw material tank 1 is filled with raw material gas obtained by vaporizing the raw material liquid at the vapor pressure at the temperature of the raw material tank 1, and between the upper space 4 of the raw material tank 1 and the reaction vessel (not shown). A pipe 5 for supplying raw material gas is arranged.

The piping 5 is provided with an open/close pulp 6, an automatic pulp 7, and a flow rate control device 8. The flow rate control device 8 includes a mass flow meter (
mass flow controllers) are widely used. A pipe 9 with an automatic pulp 10 interposed therebetween is connected to the primary side of the flow rate control device 8, and nitrogen gas is supplied through the pipe 9. The automatic valve 10 is interlocked with the automatic pargua, and when raw materials are being supplied, the automatic pargua is open and the automatic pulp 10 is closed to allow the raw material to flow into the reaction vessel, and when raw materials are not being supplied, the automatic pargua is closed and the automatic pulp 10 is closed. is opened and nitrogen gas flows into the pipe to purge the pipe to protect it.

The procedure for introducing the raw material gas into the reaction vessel using the raw material supply device shown in FIG. 3 is as follows. When raw materials are not being supplied, the automatic pulse 110 is closed, the automatic pulse 110 is open, and the piping 50 on the side opposite to the reactor is insulated with nitrogen gas.

In order to start raw material supply from such a state, first, the heater 3 is heated to heat the raw material liquid in the raw material tank, and the raw material gas pressure in the upper space 4 of the raw material tank is raised to a predetermined level above atmospheric pressure. do. For example, in order to make the raw material gas pressure about IK9/dG when the raw material liquid is s 1 cz4, the temperature of the raw material gas tank is heated to 80°C. Next, the automatic pulp 10 is closed, the automatic pulp guar is opened, and the raw material gas is sent to the reaction vessel. At this time, the flow rate control device 8 controls the feed rate of the raw material gas to a required flow rate. At the end of supplying the raw material gas, the automatic gas valve is closed, the automatic gas valve 10 is opened, and the inside of the pipe 5 is flushed with nitrogen gas. If the supply of raw material gas is not restarted in a further short time, the heater 3 is turned off and the raw material tank 1 is cooled.

<Problems to be solved by the invention> When raw material gas is supplied using a raw material supply device as shown in FIG. If so, stable supply can be achieved.

However, if the flow rate of the raw material exceeds 1.5 A/m, the raw material liquid will begin to boil in the raw material tank, and if care is not taken to maintain a stable boiling state, bumping will occur, and the flow rate will be controlled stably. This may cause problems that may lead to failure or even damage to the device. One solution to ensure stable boiling is to always have a source of bubbles in the raw material liquid. For example, by making the bottom of the raw material tank rough, or by adding a porous material that does not react with the raw material liquid to the raw material liquid. It was being put into place. However, the core of the bubbles generated from these bubble generating sources is gas having a vapor pressure higher than the pressure of the raw material tank, which is adsorbed to these bubble generating sources. Therefore, if the bubble generation source is placed in the raw material liquid for a long period of time, the gas adsorbed to the porous body will be lost, and the bubble generation source will no longer generate bubbles. For this reason, the raw material liquid is removed periodically,
It was necessary to purge the inside of the raw material tank with a gas that does not react with the raw material liquid, such as nitrogen gas. As a result, nitrogen gas and the like reach the inner wall of the raw material tank again and are adsorbed by the porous body, thereby restoring the bubble generation function.

The present invention has been made in view of the drawbacks of the prior art, and is a raw material supply device capable of continuously supplying a gas that does not react with the raw material liquid, which becomes the core of foaming of the raw material liquid, while keeping the raw material liquid in the raw material tank. The purpose is to provide the following.

Means for Solving Problems> The configuration of the raw material supply device according to the present invention that achieves the above object includes a raw material tank containing a raw material liquid that reacts with oxygen or moisture in the atmosphere, and a raw material liquid in the raw material tank. In a raw material supply device equipped with a means for heating, a pipe for guiding the raw material gas vaporized in the raw material tank to a reaction vessel, and a device for opening/closing and controlling the flow rate interposed in the pipe, the raw material liquid is Means for continuously supplying gas to the raw material liquid over a long period of time while keeping the raw material tank constantly filled with gas that does not react with the raw material liquid and becomes the core of bubbles generated by boiling of the raw material liquid. It is characterized by having the following.

Embodiment> An embodiment of the raw material supply device according to the present invention will be described with reference to the drawings. The first factor is a configuration diagram of an embodiment of the raw material supply device of the present invention in the original fiber preform manufacturing device. According to FIG. 1, an airtight raw material tank 1 contains a raw material liquid of the original fiber base material, for example, 5IC14, which reacts with oxygen or moisture in the atmosphere.
, GeCl4, and other liquid glass raw materials are maintained.

Further, a heater 3 is attached to the outer periphery of the raw material tank 1 to maintain the raw material liquid 2 at a predetermined temperature. The upper space 4 of the raw material tank 1 is filled with the saturated vapor pressure of the heated raw material liquid.
A piping 5 is led out from the upper space 4 and communicates with a reaction vessel (not shown) via an opening/closing pulp 6 and an automatic palguar t amount control device 8. A distribution g9 in which an automatic pulp 10 is interposed is connected to the primary side of the flow rate control device 8.

Further, a porous body 11 that does not react with the raw material liquid is inserted into the raw material tank 1, and a pipe 12 is connected to the porous body 11, and a gas that does not react with the raw material liquid 2, such as a gas that does not react with the raw material liquid 2, is connected to the porous body 11 and , connected to a nitrogen gas supply.

Note that a mass flow meter (mass flow controller) is widely used as the flow rate control device.

In such an apparatus, the following procedure is used to introduce the raw material gas to the reaction vessel. When raw material gas is not being supplied, the automatic pulp 7 is closed, the automatic pulp 10 is opened, and the reaction vessel side of the piping 5 is filled with nitrogen gas. To start water supply in such a situation, first turn on heater 3.
The raw material tank 1 is heated to bring the raw material liquid 2 to a predetermined temperature, and the upper space 4 of the raw material tank 1 is filled with raw material gas at a predetermined pressure equal to or higher than atmospheric pressure. For example, when the raw material liquid is 5iCZ4, in order to make the pressure of the raw material gas about IKf/cJG, the raw material liquid 2 is heated to 80°C. Next, the automatic pulp 10 is closed, the automatic pulp guar is opened, and the raw material gas is sent to the reaction vessel. The flow rate of the source gas is controlled by a light amount control device 8. When the supply of raw material gas is finished, the automatic pulp 7 is closed, the automatic pulp 10 is opened, and the inside of the pipe 5 is filled with nitrogen.
Parts with gas. If the supply of raw material gas is not restarted in a further short time, the heater 3 is turned off) and the raw material tank is cooled. When the raw material gas is not being supplied, the open/close pulp 13 is opened for a short time to send nitrogen gas to the piping 12, and the porous body 1
1), it is possible to replenish the porous body with gas that becomes the nucleus of bubbles when the raw material liquid boils. Note that even when the raw material liquid is continuously replenished and the porous body 11 is always in the raw material liquid 2, bubble generation from the porous body can be continued. It is not necessary to supply nitrogen gas to the porous body 11 too often; for example, it is sufficient to supply nitrogen gas to the porous body 11 once every five times the raw material gas is supplied. Of course, it is even more sufficient to carry out the process every time the raw material gas supply is finished.

An experiment was conducted to confirm the effectiveness of the raw material supply device of the present invention using the device shown in FIG.

The raw material tank 1 was a container capable of containing 5 iCl of the raw material liquid, and the raw material gas was supplied at a rate of 5 tc14/m for 6 hours a day. Further, the raw material liquid 2 in the raw material tank 1 was maintained at 3.5-51 using a continuous replenisher. As a result of this experiment, when nitrogen gas was supplied to the porous body 11 for about 1 minute once every 3 days when the raw material gas was not supplied,
Even after 10 days, sufficient bubbles were generated from the porous body 11, and stable boiling of the raw material liquid was maintained. In the case where nitrogen gas was not supplied to the porous body 11, almost no bubbles were generated from the porous body 11 on the 10th day.

As described above, according to the present invention, the raw material liquid 2 is supplied to the raw material tank 1.
It has become possible to continue supplying gas that does not react with the raw material liquid, which forms the nucleus of boiling bubbles, into the raw material liquid while maintaining the state in which the liquid is contained. For this reason, the raw material liquid can be kept boiling stably, and it has become possible to send a large amount of raw material gas to the reaction vessel while stably controlling the flow rate.

In the above-described embodiments of the present invention, by supplying gas that does not react with the raw material liquid to the porous body while the raw material gas is not being supplied, the nucleus of bubbles generated by boiling in the porous body is always formed. There are some products that adsorb gas, but the gist of the present invention is to take measures to ensure that there is always gas in the raw material liquid that will form the nucleus of bubbles (due to boiling). As in the conventional example, things adsorbed to the inner wall of the raw material tank,
It does not need to be adsorbed onto a porous body as in the above embodiments, and may be constantly supplied from the outside.

FIG. 2 shows a configuration diagram of another embodiment of the raw material supply device according to the present invention. In the example shown in FIG. 2, the porous body 11 is connected to the tip of the pipe 12 in the example shown in FIG. It's now 16. The automatic pulp 16 is opened during raw material supply and sends an inert gas such as nitrogen gas to the raw material tank 1. Further, a flow rate control device 17 is interposed in the piping 12 . In this embodiment shown in FIG. 2, when feeding the raw material gas to the reaction vessel, a raw material gas piping system 5 and a nitrogen gas piping system 1 are used.
The automatic pulp 7.16 with 2 opens and closes in conjunction with each other to send the raw material gas to the reaction vessel. While the raw material gas is being sent to the reaction vessel, a small amount of nitrogen gas, which becomes the nucleus of bubbles generated by boiling of the raw material liquid, flows through the pipe 12 into the raw material liquid 2 through the nozzle 1,
5 is constantly supplied. In the case of this embodiment as well, it is possible to continue generating gas that does not react with the raw material liquid, which becomes the nucleus of bubbles generated by boiling in the raw material liquid 2, while maintaining the state in which 1 yen of the raw material liquid 2 is contained in the raw material tank. I wish I could do it,
By stably continuing boiling, the raw material gas can be sent to the reaction vessel while stably controlling the flow rate. In this case, in the experiment, the flow rate of the nitrogen gas that does not react with the source gas is 3Qcc/I &
It was confirmed that boiling could be continued at a sufficient temperature.

Note that the raw material gas to be sent to the reaction vessel is not limited to pressures above atmospheric pressure; if the pressure is below atmospheric pressure, simply inserting a siphon pipe into the raw material tank l will remove the inert gas that forms the nucleus of bubbles. Guided into tank 1.

<Effects of the Invention> According to the raw material/supply device according to the present invention, a means is provided in which a gas serving as the core of bubbles generated by boiling is always present in the raw material liquid in the raw material tank. A device that supplies a gas that does not react with the raw material gas to the porous body while gas is not being supplied, so that the porous body adsorbs the gas that forms the nucleus of bubbles generated by boiling, or a raw material tank. By continuously replenishing the raw material liquid into the tank, the raw material liquid is kept in the raw material tank, and the flow rate of the raw material gas is maintained at the desired value by the flow rate control device.
By continuing to supply a gas that does not react with the raw material liquid, which becomes the nucleus of boiling bubbles, into the raw material liquid, a large amount of raw material gas can be stably supplied to the reaction vessel for a long period of time.

In the above-described embodiments of the present invention, a raw material supply device for manufacturing optical fiber base materials has been described, but the raw material supply device according to the present invention can also be widely used as a raw material supply device for manufacturing semiconductor materials. It is something that can be done.

[Brief explanation of the drawing]

1 and 2 are block diagrams of an embodiment of a raw material supply apparatus according to the present invention, and FIG. 3 is a block diagram of a conventional raw material supply apparatus. In the drawings, 1 is the raw material tank, 2 is the raw material liquid, 3 is the heater, 4 is the upper space of the raw material tank, 5.9.12 is the piping, 6.13 is the open/close pulp, 7.10.16 is the automatic pulp, 8 11 is a porous body, 15 is a nozzle, and 17 is a flow rate control device.

Claims (1)

[Claims] a raw material tank containing a raw material liquid that reacts with oxygen or moisture in the atmosphere; a means for heating the raw material liquid in the raw material tank;
In a raw material supply device equipped with a pipe that guides the raw material gas vaporized in the raw material tank to a reaction vessel, and a device loaded in the pipe for opening/closing and controlling the flow rate, the raw material liquid is constantly filled in the raw material tank. It is characterized by comprising a means for continuously supplying gas, which does not react with the raw material liquid and becomes the core of bubbles generated by boiling of the raw material liquid, into the raw material liquid for a long period of time while maintaining the same state. Raw material supply equipment.