KR840002178B1 - Reactant delivery system method - Google Patents

Abstract

Deposition equipment used to form material for light-guide tubes consists of sealed storerooms (18, 20, 22), which contain liq. raw material; heating devices (24, 26, 28) to heat the storerooms; pumping equipment to supply the reaction vapor; a burner to form the reaction product, a flow control valve (48, 50, 52), a flow velocity converter (66, 68, 70), a controller (60, 62, 64), an operation device for the controller (54, 56, 58), a pouring device for the reaction soot (74, 76, 78, 80, 82), and a system controller (72).

Description

Deposition apparatus for forming material of optical waveguide

1 is a schematic view of a deposition apparatus for forming a blank of a light waveguide according to the present invention.

2 is a partial cross-sectional view of the burner used in the deposition apparatus of FIG.

The present invention relates to a vapor deposition apparatus for forming a material of an optical waveguide by directly directing a reaction product of vaporized raw material or vapor to a starting member.

The material thus formed is drawn into an optical waveguide.

It has been found that if any prerequisite is met, the light beam propagates into the discontinuous mode within the elongated transparent body, for example a filament of glass or the like. The size of the filament, the radial change in the refractive index and other conditions are combined to determine the effectiveness of the filament as a transmission medium for optical communication. The internal properties of the filaments must be tightly controlled to transmit light without excessive dispersal between propagation modes and to transmit light only in predetermined modes.

A filament suitable for use as an optical waveguide is formed by heating a cylindrical material of a transparent dielectric material such as glass and drawing it into a predetermined elongate structure. The structural properties of the waveguide are closely related to the properties of the material to be drawn, in particular, the refractive index gradient. Reflect.

According to the general method, the drawn material is formed by coating a rotating cylindrical starting member with a continuous layer of sinterable glass soot. The soot is formed by the deposition of fine siliceous particles applied to the surface of the material through an oxidation reaction flame mechanism.

Flames used for sintering and depositing particles on the surface of glass materials are well known to those having ordinary skill in the art as "hydrolysis flames". However, the exact phenomenon is not yet fully understood, but recent studies suggest that the actual reaction is more suitable for oxidation. Therefore, in the examples of the present invention, this reaction will be defined as "oxidizing", and it should be noted first that the exact nature of this chemical reaction is not very important to the practice of the present invention. A siliceous matrix matrial, such as silicon tetrachloride, is fed to the burner that ejects the flame in the form of steam, and other materials defined as additives are also controlled at certain points in order to change the optical properties of the final product. Supplied in quantities. Embodiments of the present invention have been described in connection with the production of silicate glass, but silica-free glass containing, for example, germanium may also be formed by the apparatus of the present invention.

Various evaporated or sprayed materials combine with oxygen in the burner flame to form tiny spherical particles that remain molten and propel toward the surface of the material by flame force. In this way, deposits, commonly referred to as " soots, " are deposited along the helical trajectory, with the various layers immersed to form a continuum.

In other known processes, various steam raw materials are also introduced into a heated tube, which is deposited in a continuous layer in the tube and then the tube collapses to leave the molten material. The material is then sequentially heated and drawn into elongated filaments.

Generally, the raw materials are brought into a gaseous state and transported due to the necessity of supplying the hydrolysis burner in a substantially constant flow to form a material containing uniform properties and to distribute the glass forming suit evenly. A system for controlling the rate of gas incorporation and carrier gas flow has been invented. However, due to the large number of factors that determine the amount of vapor introduced into the hydrolysis flame at any point in time, variations in the deposition rate of various vapor deposition processes often result in unnecessary, non-uniform properties in the formed material.

Attempts have been made to use a carrier gas to deliver the reaction vapors, in which a column with a packing is used, and a pump is provided for circulating the liquid raw material through the packing. Pressurized carrier gas flows through the introduction tube into the packing, and steam of the raw material is embedded in the carrier gas. The gas leaves the column through the vent and goes to where it will be deposited. However, even if the steam flow rate is accurately controlled, the pressure and temperature in the liquid raw material reservoir must be precisely controlled. Therefore, it is highly desirable to provide a control system for delivering gaseous raw materials to a hydrolysis burner consistently without precisely controlling the temperature and pressure in the raw material reservoir.

U. S. Patent No. 4, 173, 305 by the Applicant refers to a device for supplying a precisely controlled amount of reaction vapor to a discharge means, in which the various product components are in liquid form in a reservoir. An improved pump is connected to each reservoir to deliver a predetermined amount of liquid component to the mixing stage so that the various liquids are thoroughly mixed and then sprayed.

The material vapor is sent to a discharge means such as a reaction burner or the like. Raw material vapors react in a flame according to conventional methods and are deposited on a substrate to form the material of an optical waveguide. However, the apparatus disclosed in U.S. Patent Nos. 4, 173 and 305 may control the amount of various reaction product components precisely, but there is a disadvantage that the price is expensive because output pumps and the like are used.

In addition, the device disclosed in the prior art US Patent No. 4, 062, 665 is equipped with a pipe for supplying a carrier gas such as argon, hydrogen, oxygen to the raw material reservoir, the reservoir is bathed at a constant temperature Housed within to maintain the liquid component at the desired desired temperature to maintain a constant vapor pressure, but the apparatus according to the invention heats the liquid raw material in the reservoir to a temperature sufficient to convert the heating means into a vapor of sufficiently high pressure. The vapor pressure in each reservoir is varied above a sufficiently high vapor pressure.

In other words, the present invention uses a heating means to raise the steam pressure to a sufficiently high pressure, unlike US Patent No. 4, 062, 665, which maintains a constant steam pressure in each reservoir.

It is an object of the present invention to deliver waveguide product to a reaction burner or the like without the need for carrier gas and without the need to accurately control the temperature and pressure in the raw material reservoir, and without the need for expensive components such as pumps in the US patent. To control the dense vapor flow of the material.

In summary, the present invention provides at least two or more sealed reservoirs 18, 20, 22 containing liquid raw materials therein, and heating means 24, 26, 28 for heating the respective reservoirs; A vapor deposition apparatus for forming a material of an optical waveguide comprising a pumping means for supplying reaction vapors and a means such as burner 12 for forming a reaction product,

A flow rate control valve 48, 50, 52, a flow rate converter 66, 68, 70 for detecting and converting the flow rate in relation to the pumping means, a controller 60, 62, 64, and the flow rate control A controller operating mechanism (54, 56, 58) for operating the valve and means (74, 76, 78, 80, 82) for injecting a reaction suit forming gas into the vapor downstream flow of the control valve; System control unit 72 for supplying a control signal to each of the controllers (60, 62, 64),

In order to deliver the waveguide forming material in the form of steam from the reservoirs 18, 20, 22 to the burner 12 without the need for the pumping means and the carrier gas, it is contained in the reservoirs 18, 20, 22. The heating means 24, 26, 28 heat-control the liquid raw materials in the reservoirs 18, 20, 22 to a sufficiently high temperature so as to convert the liquid raw materials into sufficiently high vapor pressures. 22 from the steam flow controller (48, 54, 60, 66 or 50, 56, 62, 68 or 52, 58, 64, 70) or the reaction burner (for the respective reservoirs 18, 20, 22); 12) characterized in that the conveying.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As illustrated in FIG. 1, one layer of the glass suit is applied to the substantially cylindrical axis or to the starting member 10 by means of a release, such as flame hydrolysis burner 12. The starting member 10 is usually translated relative to the burner 12 to form a cylindrical preform 16. Hereinafter, the formation of a material that can be drawn into an optical waveguide will be described.

As is known to those skilled in the art, the substrate or starting member 10 is sequentially removed sequentially by mechanical or chemical processes to leave only the deposited material. The cylindrical material is drawn sequentially into elongated waveguides, the properties of the elongated waveguides reflect the composition of the reaction product components. In the present invention, instead of a flame process for depositing a predetermined reaction product on the outer surface of the starting member 10, a steam reaction is performed in a heated region of the base tube, and so-called glass deposition is performed on the inner surface of the tube. The same applies to the "internal vapor phase oxidation method".

Components optimally injected into the reaction product are typically maintained in pressurized tank reservoirs 18, 20 and 22. The reservoirs 18, 20 and 22 have a heater 24 for maintaining the temperature of the reactants sufficiently high to maintain the temperature at a level sufficient to adequately flow the material into the burner 12 at the vapor pressure in the reservoir. (26) (28) is provided. The minimum vapor pressure for flowing the vapor to the burner is 4 psig. The maximum pressure in the reservoir is limited by a device such as the flow controller described below, with a preferred maximum operating pressure of 650 psig. The temperature controllers 30, 32, and 34, which maintain the raw materials in the respective reservoirs 18, 20, and 22 at an appropriate temperature, use Model 383 Robert shaw Controller or Eurotherm Controller, which are currently widely used commercially. do. Each of the pressure sensors 36, 38, 40 supplies a control signal to the temperature controllers 30, 32, 34, respectively. Thus, the pressure in the reservoir is monitored and the information thus produced is used to control the operation of the heating means 24, 26, 28. The valves 42, 44 and 46 installed in the pipes 41, 43 and 45 are respectively connected to the respective reservoirs in order to control the flow of steam as necessary and to completely block various steam flows for exchange of the reservoirs. It is connected. Flow control valves 48, 50 and 52 are provided in the respective pipes 41, 43 and 45, respectively, to control the flow rate of each steam from the reservoirs 18, 20 and 22.

The flow control valves 48, 50, 52 are electronically controlled by the actuators 54, 56, 58 of the controller 60, 62, 64 to make the system easier to operate. It is necessary to be. For this purpose the controller actuators 54, 56, 58 are respectively connected to the flow control valves 48, 50, 52 and steam from the reservoirs 18, 20, 22. It is operated by the controllers 60, 62 and 64 to control the flow of the in some way. Flow rate converters 66, 68 and 70 are arranged to detect the flow rate with the pipes 41 and 43 and 45, respectively, to convert the flow rate. The signals drawn by the transducers 66, 68, 70 are applied to the controllers 60, 62, 64 so that the flow rate of the vapor can be controlled. The flow rate control valve, the controller operating mechanism, the controller, and the converter, which are indicated by the above-described examples 48, 54, 60, and 66, respectively, are collectively called a flow rate speed controller. Such a controller is a flow rate system of the prior art, and an example of such a controller is a product of "Tylon" Tylon model FC-260 "of Tylon, Inc., Terrance, California. 54 constitutes an electric heater connected to the valve 48 which constitutes a differential expansion tube with a ball which is relatively moving relative to the valve seat to convert the ball-to-seat opening. Each of the controllers 60, 62 and 64 has a setpoint input terminal connected to a system controller 72 composed of a computer or a microprocessor programmed to supply appropriate control signals to each controller. Device 72 includes an AD converter with a Mode1 3911A controller, a Model 1500 CAMAC crete (kinetic systems, Inc.) connected to a PDP 11/34 computer using a VT52 video terminal, and a programmer console. It consists of an All, DEC writer, RK11T disc and software, all of which are manufactured by Digital Equipment, Inc. The flow of steam from pipes (41) (43) (45) is connected to burner (12). The steam outlet pipes 41, 43, 45 and 71 must be heated to a temperature at least heated to the pressurized tank reservoirs 18, 20 and 22. Oxygen also oxygen source 74 The downstream flow of the combined steam must be introduced into the tube 71. The oxygen flow rate is controlled by a flow controller consisting of a valve 76, a motor 78, a controller 80 and a transducer 82. The flow rate of oxygen is controlled as a function of the flow rate of the vapor component so that an appropriate amount of oxygen is introduced into the system, although it may be desirable to inject some oxygen into the reaction steam, this step is not necessary and is one of the advantages of the system. Carrier gas is not used as a means of transporting the reactant vapor. Therefore, more dense flow of reaction product components can be achieved.

While oxygen needs to form various oxides that make up the soot formed in the flame of burner 12, such oxygen may be provided at the burner. A partial cross sectional view of the burner 12 is illustrated in FIG. 2, where an orifice 86 located at the center of the burner face 84 is surrounded by concentric rings of the orifices 88, 90 and 92. have. Reaction steam is discharged from the orifice 86, which is likely to be heated by the flame generated by the oxygen and fuel gas emitted from the orifice 90. A flow of oxygen, called an inner shield, is released from the orifice 88, which prevents the reaction of the reaction components in front of the burner. The flow of oxygen, also called the outer shield, is released from the orifice 92. The burner design is similar to that described in US Pat. No. 3, 698, 936, except that the annular slot provides an inner shield in the present patent application and there is no outer seal orifice. All orifices of burner 12 may be supplied by a manifold similar to that of US Pat. No. 3,698,936.

Referring again to FIG. 1, the flue gas and oxygen supplied to the burner 12 by the tube 14 are ejected from the burner and ignited. Additional oxygen is supplied by the tube 15. The reaction vapor supplied by the tube 71 reacts in the flame to form a glass suit. Chlorine or other materials that have been previously combined with the matrix and additives are separated from the materials and combine with hydrogen from the hydrocarbon fuel to form hydrochloric acid. The inherent nature of the reaction depends on the components present and the particular application of the invention. Such a reaction itself does not form part of the present invention, and it is contemplated that other components than those described herein may be used without departing from the spirit of the present invention. In addition, deposition apparatuses of the same type as the above-described internal vapor deposition apparatus or other mechanisms for transferring some additives to the substrate may be used for use with the present invention. In the description of the present invention additional oxygen above the theoretical amount required for the combustion of the fuel without oxygen as the carrier gas is sent to burner 12 in the manner described in connection with FIG.

For use in the system described in the formation of optical waveguides having SiO ₂ , GeO ₂ and B ₂ O ₃ , the pressurized tank reservoirs 18, 20 and 22 each hold SiCl ₄ , GeCl ₄ and BCl ₃ . . Of course, many other glass forming reagents can also be used which can be sent in vapor form. The temperature controllers 30, 32, 34 are adjusted so that the vapor pressure in each reservoir is high enough that steam can be sent to the burner or other means of utilization through the flow controller. Although a minimum pressure of 4 psig is used, in a practical embodiment the pressure in the reservoir is maintained at about 12 psig. To provide this pressure, the temperatures of SiC1 ₄ , GeCl ₄ and BCl ₃ are maintained at about 76 ° C., 105 ° C. and 30 ° C., respectively.

The system controller 72 opens the valves 42, 44 and 46 to allow the valves 48, 50 and 52 to pass a predetermined amount of steam through the burner 12, thereby fitting the respective flow controllers. Provide a setpoint signal. Appropriately improved fluidized oxygen is also introduced into the burner with the reaction steam. The vapor reacts with oxygen in the flame to form the soot deposited on the surface of the soot preform 16. The shaft 10 is removed from the finished preform, which is heat cured from a single glass material that can be received into the optical waveguide by conventional methods.

In order to radially change the refractive index of the waveguide structure, the proportions of the various components change in a predetermined manner during the formation of the material.

To accomplish this purpose, the system controller 72 generates command signals for various flow controllers at predetermined times such that the type or amount of additive changes. Typically, this change reduces the refractive index of the final glass article with increasing preform radius. Therefore, the flow control valves 48, 50 and 52 adjust the flow of the reaction steam as appropriate. The enclosed form of the steam delivery system allows the reaction vapor to be delivered to the deposition apparatus extremely accurately. Therefore, precise control of the pressure and temperature of the liquid in the reservoir is not necessary and only the pressure therein needs to be kept high enough so that steam can be transferred to the burner through the flow controller.

It will be appreciated that an improved system for delivering gaseous raw materials to the deposition means in a precisely controlled manner has been described above.

As described above, in the present invention, the at least one reservoir contains a liquid composed of a silicon compound, and the other reservoir contains a liquid composed of an additive for determining the refractive index of the material of the siliceous optical waveguide. It is characterized by introducing oxygen as the reaction soot forming gas.

The invention also provides means for controlling the temperature of the heating means (30, 32, 34) for each reservoir, and a control signal for controlling the temperature of the heating means to ensure a predetermined vapor pressure in each reservoir. A pressure sensor (36, 38, 40) disposed in each reservoir for providing to a controller, and means for delivering steam from each reservoir to be combined with the reaction burner by the pumping means. do.

As described above, it is to be understood that the present invention is not limited to the specific embodiments described and that other changes and adaptations may occur to those skilled in the art. For example, the external vapor deposition method is described in detail with reference to the accompanying drawings, but the system itself is also applied to the internal vapor deposition method, and the vapor flow in the deposition means must be controlled within a narrow range. Accordingly, it will be understood that various modifications and variations may be made without departing from the scope of the present invention.

Claims (1)

At least two sealed reservoirs 18, 20, 22 containing liquid raw material therein, heating means 24, 26, 28 for heating each reservoir and pumping for supplying reactive vapors A vapor deposition apparatus for forming a material of an optical waveguide composed of means and means such as burner 12 for forming a reaction product, A flow rate control valve 48, 50, 52, a flow rate converter 66, 68, 70 for detecting and converting the flow rate in relation to the pumping means, a controller 60, 62, 64, and the flow rate control Controller actuating mechanisms 54, 56, 58 for operating the valve, means 74, 76, 78, 80, 82 for injecting a gaseous reaction suit into the vapor downstream flow of the control valve; And a system controller 72 for supplying the control signal to each of the controllers 60, 62, and 64, In order to deliver the waveguide forming material in the form of vapor from the reservoirs 18, 20, 22 to the burner 12 without the need for the pumping means and the carrier gas, it is contained in the reservoirs 18, 20, 22. The heating means 24, 26, 28 heat-control the liquid raw materials in the reservoirs 18, 20, 22 to a sufficiently high temperature so as to convert the liquid raw materials into sufficiently high vapor pressures. 22 from the steam flow controller (48, 54, 60, 66 or 50, 56, 62, 68, or 52, 58, 64, 70) or the reaction burr for each reservoir (18, 20, 22). Deposition apparatus for forming the material of the optical waveguide, characterized in that the transfer to the inner (12).

Images