JP2011132090A - Method and apparatus for supplying zinc vapor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for supplying zinc vapor, supplying zinc vapor at a constant supply rate to an apparatus using zinc vapor. <P>SOLUTION: In the method for supplying zinc vapor by exhausting evaporated zinc vapor from a zinc evaporator and supplying the zinc vapor to a subsequent stage apparatus while supplying molten zinc 2 to a zinc evaporator 1, the molten zinc is supplied at a constant supply rate to the zinc evaporator; the height of liquid level of zinc in the zinc evaporator is measured; and zinc in the zinc evaporator is evaporated so as to make constant the height of liquid level of zinc. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a zinc vapor supply method and a zinc vapor supply apparatus for supplying zinc vapor to an apparatus in which zinc vapor is used, and particularly to supply zinc vapor to a reactor for producing polycrystalline silicon. The present invention relates to a zinc vapor supply method and a zinc vapor supply apparatus.

With the spread of solar cells in recent years, the demand for polycrystalline silicon is increasing rapidly. Conventionally, the Siemens method (Siemens Method) is mentioned as a method of manufacturing a high purity polycrystalline silicon. The Siemens method is a method of reducing trichlorosilane (SiHCl ₃ ) with hydrogen (H ₂ ). Polycrystalline silicon produced by the Siemens method has a very high purity of eleven-nine (11-N) and is used as silicon for semiconductors. Although the silicon for solar cells has also used a part of the product manufactured as this silicon for semiconductors, it does not require a purity as high as 11-N, and the Siemens method consumes a lot of power. There is a need for an inexpensive manufacturing method suitable for silicon.

Under such circumstances, a method for producing polycrystalline silicon by a zinc reduction method has been proposed as a method for producing silicon for solar cells, and the reaction thereof is represented by the following formula (1):
SiCl ₄ + 2Zn = Si + 2ZnCl ₂ (1)
It is shown by.

  In the method for producing polycrystalline silicon by the zinc reduction method, the purity of the produced polycrystalline silicon is about six-nine (6-N), which is lower than that of silicon for semiconductors, but compared with the Siemens method. It is a production method that is excellent in reaction efficiency and advantageous in production cost as much as about 5 times.

  As a method for producing polycrystalline silicon by a zinc reduction method, there is a method for producing polycrystalline silicon in which silicon tetrachloride vapor and zinc vapor are supplied to a reaction furnace to deposit polycrystalline silicon in the reaction furnace. In order to stably produce polycrystalline silicon by such a polycrystalline silicon production method, it is important that the raw material vapor is supplied into the reaction furnace at a constant supply rate.

  Since the boiling point of silicon tetrachloride vapor is as low as 57.6 ° C., the flow rate of the vapor can be measured with a flow meter, so the flow rate can be installed to control the supply rate of the silicon tetrachloride vapor. According to the "Handbook" (edited by the Chemical Society of Japan), the boiling point of zinc is very high at 907 ° C, so it is difficult to measure the steam flow rate with a gas flow meter. It was difficult to control.

  As a method for measuring the flow rate of zinc, for example, as a flow rate measurement of molten zinc in a molten metal plating apparatus, the moving speed of particles in the molten zinc, the area of the cross section in the tank orthogonal to the flow of molten zinc, and the density of molten zinc (Patent Document 1).

  In addition, when supplying zinc by continuous hot dip galvanization, there is a premelt method in which zinc is melted in advance and supplied to the zinc pot. Measurement has been reported (Patent Document 2).

JP 2001-288548 A (paragraph number 0020) Japanese Patent Laid-Open No. 3-207843 (second page, lower right column, third line)

  However, both of the methods described in Patent Documents 1 and 2 are methods for measuring the flow rate of molten zinc, and are not methods for measuring the flow rate of zinc vapor.

  Conventionally, when supplying zinc vapor to a device using zinc vapor, there is no method for accurately measuring the supply rate of zinc vapor, and therefore there is no method for supplying zinc vapor to the device at a constant supply rate.

  Accordingly, an object of the present invention is to provide a zinc vapor supply method and a zinc vapor supply device capable of supplying zinc vapor to an apparatus using zinc vapor at a constant supply rate.

  As a result of intensive studies to solve the problems in the prior art, the inventors of the present invention discharged molten zinc vapor from the zinc evaporator while supplying molten zinc to the zinc evaporator. When supplying to the apparatus, while supplying the molten zinc to the zinc evaporator at a constant supply rate, the height of the zinc liquid level in the zinc evaporator is measured, and the zinc liquid level is measured. It is found that by controlling the temperature of the zinc evaporator so that the height is constant and evaporating the zinc in the zinc evaporator, zinc vapor can be supplied to the subsequent apparatus at a constant supply rate. The present invention has been completed.

  That is, the present invention (1) is a method of supplying a constant amount of zinc vapor, in which molten zinc is supplied to the zinc evaporator, and the evaporated zinc vapor is discharged from the zinc evaporator and supplied to the subsequent apparatus. While supplying the molten zinc to the zinc evaporator at a speed and measuring the height of the zinc liquid level in the zinc evaporator, the height of the zinc liquid level is kept constant. The present invention provides a method for supplying zinc vapor characterized by evaporating zinc in a zinc evaporator.

  Further, the present invention (2) includes a zinc evaporator, molten zinc supply means for supplying molten zinc to the zinc evaporator at a constant speed, and zinc for discharging the evaporated zinc from the zinc evaporator. A non-contact distance measuring device for measuring a distance between a vapor discharge pipe and a zinc liquid level in the zinc evaporator; and a distance between the zinc liquid level and the non-contact distance measuring device. Control means for calculating a zinc liquid level from the distance, and outputting an output control signal to the heater of the zinc evaporator so that the zinc liquid level is constant. A zinc vapor supply device is provided.

  According to the present invention (3), the non-contact distance measuring device generates a laser beam for distance measurement modulated at a predetermined modulation frequency, and the laser beam for measurement is measured. A laser beam transmitter that emits light toward a point, a light receiver that receives reflected light reflected from the measurement point, and a phase difference detector that detects a phase difference between the reflected light and the laser beam for measurement And a zinc vapor supply device according to the present invention (2), characterized in that it is a laser-type distance measuring device having a calculation unit for calculating the distance from the phase difference to the measurement point. is there.

  ADVANTAGE OF THE INVENTION According to this invention, the supply method of the zinc vapor | steam which can supply zinc vapor | steam to the apparatus using zinc vapor | steam with a fixed supply speed, and the supply apparatus of zinc vapor | steam can be provided.

It is a schematic diagram which shows the supply apparatus of the zinc vapor | steam of this invention.

  The zinc vapor supply method of the present invention and the zinc vapor supply apparatus of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing a zinc vapor supply apparatus of the present invention. In FIG. 1, for convenience of explanation, the zinc evaporator and the zinc melter are shown in cross-sectional views.

  In FIG. 1, a zinc vapor supply device 20 includes a zinc evaporator 1, a heater 7 for heating the zinc evaporator 1, a zinc melter 2, and a heater 9 for heating the zinc melter 2. And a granular zinc meter 3, a laser beam generator 18 for generating a distance measuring laser beam, and transmitting the distance measuring laser beam to a zinc liquid surface 23 in the zinc evaporator 1 and The laser beam transmitter / receiver 4 that receives the reflected light reflected from the zinc liquid surface 23, the reflected light received by the laser beam transmitter / receiver 4 and the distance measuring laser beam Calculated by the phase detector 5 for detecting the phase difference, the calculator 22 for calculating the distance from the laser beam transmitter / receiver 4 to the zinc liquid level 23 from the phase difference, and the calculator 22. From the laser beam transmitter / receiver 4 to the zinc liquid surface 23 And a control means 6 for controlling the output of the heater 7 of the zinc evaporator 1 based on the release, the.

  The granular zinc meter 3 is a granular zinc meter for measuring a certain amount of granular zinc at regular intervals and supplying it to the zinc melter 2. That is, the granular zinc meter 3 supplies granular zinc to the zinc melter 2 at a constant supply rate. A method of supplying granular zinc to the zinc melter 2 at a constant supply rate using the granular zinc meter 3 is not particularly limited. For example, from the inside of the granular zinc storage unit of the granular zinc meter 3 The granular zinc meter 3 so that a set amount of granular zinc is metered at regular time intervals (for example, 30 g of granular zinc is metered every 30 seconds) and fed to the zinc melter 2. A method of programming the control unit, for example, a screw feeder type supply method of controlling the rotation speed of the screw feeder so that 30 g of granular zinc is supplied every 30 seconds. At that time, the amount of granular zinc measured per measurement interval, the number of rotations of the screw feeder, etc. are determined according to the zinc zinc supply rate to the device installed at the subsequent stage of the zinc vapor supply device 20. It is suitably selected so as to be the same as the installation value of the supply speed.

  The granular zinc weighed by the granular zinc meter 3 passes through the granular zinc supply unit 11 of the granular zinc meter 3 and the granular zinc supply pipe 24 connected to the granular zinc supply unit 11, The melter 2 is supplied. In addition, the shape of zinc measured by the granular zinc meter 3 is not limited to a granular shape, and can be measured by the granular zinc meter 3 and can be supplied at a constant supply speed. Any size is acceptable.

  The zinc melter 2 is a zinc for melting the solid zinc supplied from the granular zinc meter 3 by heating to a temperature equal to or higher than the melting point of zinc using the heater 9 to obtain molten zinc 16. The melter. The granular zinc supply pipe 24 is connected to the zinc melter 2. The zinc melter 2 is provided with an overflow pipe 12, and the molten zinc 16 overflows by the amount of granular zinc supplied from the granular zinc meter 3 to the zinc melter 2. It is discharged from the zinc melter 2 and supplied to the zinc evaporator 1.

  Then, by supplying granular zinc from the granular zinc meter 3 to the zinc melter 2 at a constant supply rate, the molten zinc 16 overflows from the zinc melter 2 at a constant discharge rate. The molten zinc 16 is supplied to the zinc evaporator 1 at a constant supply rate. That is, in FIG. 1, the granular zinc meter 3, the granular zinc supply pipe 24, the zinc melter 2, and the overflow pipe 12 supply molten zinc to the zinc evaporator 1 at a constant supply rate. It is the supply means 25 (the part enclosed with the dashed-dotted line of the code | symbol 25 in FIG. 1) 25 of molten zinc.

  The heating temperature of the zinc melter 2 is a temperature equal to or higher than the melting point of zinc, and is usually 420 to 850 ° C, preferably 600 to 800 ° C.

  The zinc evaporator 1 is a zinc evaporator for generating zinc vapor by heating and evaporating the zinc 15 to a temperature not lower than the boiling point using the heater 7. The zinc evaporator 1 is connected to the overflow pipe 12. The zinc evaporator 1 is provided with a zinc vapor discharge pipe 8, and the zinc vapor discharge pipe 8 is connected to a subsequent apparatus. And the zinc vapor | steam 10 which generate | occur | produced in this zinc evaporator 1 is supplied to the apparatus of a back | latter stage through this discharge pipe | tube 8 of zinc vapor | steam.

  The heater 7 of the zinc evaporator is an electric heater and receives an output control signal 21 output from the control means 6. When the output control signal 21 is a signal for increasing the output, the heater 7 increases the output to increase the temperature in the zinc evaporator 1, and when the output control signal 21 is a signal for decreasing the output, the heater 7 The output is lowered to lower the temperature in the zinc evaporator 1.

  In addition, above the zinc evaporator 1, that is, above the zinc liquid level 23 in the zinc evaporator 1, the laser beam transmitter / receiver 4 is installed.

  In FIG. 1, the laser beam generator 18, the laser beam transmitter / receiver 4, the phase difference detector 5, and the calculator 22 are represented by a laser-type distance measuring device 17 (one reference numeral 17 in FIG. 1). Part surrounded by a chain line). The laser type distance measuring device 17 is a distance between the zinc liquid level 23 and the laser type distance measuring unit 17, more specifically, the zinc level 23 and the laser beam transmitting / receiving unit 4; It is a distance measuring device for measuring the distance. The laser beam generator 18 is a laser beam generator for measuring distance, that is, a laser beam transmitted toward the zinc liquid surface 23. The laser beam transmitter / receiver unit 4 A laser beam transmitter / receiver for transmitting a distance measuring laser beam toward the zinc liquid surface 23 and receiving reflected light reflected by the zinc liquid surface 23, and detecting the phase difference The unit 5 is a phase difference detection unit for detecting the phase difference between the reflected light and the distance measuring laser beam, and the calculation unit 22 calculates the zinc liquid level 23 and the laser beam from the phase difference. It is a calculation part which calculates the distance with the transmission part / light-receiving part 4.

  In the laser type distance measuring device 17, first, the laser beam generator 18 generates a distance measuring laser beam modulated at a predetermined modulation frequency, and then the generated distance measuring laser beam. Is transmitted toward the zinc liquid surface 23 from the laser beam transmitter / receiver 4. The transmitted laser beam for distance measurement is reflected by the zinc liquid surface 23, so that the reflected light is received by the laser beam transmitter / receiver 4. Next, the phase difference detection unit 5 detects a phase difference between the reflected light and the distance measuring laser beam, and outputs a detected phase difference signal 26 to the calculation unit 22. Next, the calculation unit 22 calculates the distance between the zinc liquid level 23 and the laser beam transmitter / receiver 4 (the zinc liquid level 23 and the laser distance measuring device 17 from the phase difference). Distance) is calculated, and a signal indicating the calculated distance between the zinc liquid level 23 and the laser beam transmitting / receiving unit 4 is output to the control means 6.

  The control means 6 is connected to the calculation unit 22 of the laser type distance measuring device 17, and the liquid level 23 of the zinc transmitted from the calculation unit 22 and the transmitter / receiver unit 4 of the laser beam. A signal 19 of a distance (a distance between the zinc liquid level 23 and the laser-type distance measuring device 17) is captured. First, the control means 6 captures and records the value of the distance between the zinc liquid level 23 and the laser beam transmitting / receiving unit 4 at the start of supply of zinc vapor. The height of the zinc liquid level 23 at the start of zinc vapor supply is calculated from the distance between the zinc liquid level 23 at the start of zinc vapor supply and the laser beam transmitting / receiving unit 4. That is, by measuring the distance between the zinc liquid level 23 at the start of zinc vapor supply and the laser beam transmitter / receiver 4, the height of the zinc liquid level 23 at the start of zinc vapor supply is measured. Will be measured.

  Next, the value of the distance between the zinc liquid surface 23 during supply of zinc vapor and the laser beam transmitter / receiver 4 is taken in at regular time intervals. The height of the zinc liquid surface 23 during supply of zinc vapor is calculated from the distance between the zinc liquid surface 23 during supply of zinc vapor and the laser beam transmitter / receiver 4. That is, the height of the zinc liquid surface 23 during the supply of zinc vapor is measured by measuring the distance between the zinc liquid surface 23 during the supply of the zinc vapor and the laser beam transmitter / receiver 4. It will be.

  And every time the value of distance is taken in, the distance between the zinc liquid surface 23 at the start of supply of the zinc vapor and the laser beam transmitter / receiver 4, and the zinc liquid surface during supply of the zinc vapor The difference in distance between the laser beam transmitter 23 and the light receiving unit 4 (at the start of supply of zinc vapor-at the time of each intake during supply of zinc vapor) is calculated. From the difference in distance, the difference between the height of the zinc liquid surface 23 at the start of supply of zinc vapor and the height of the zinc liquid surface 23 at the time of taking in the value of each distance during supply of zinc vapor is grasped. .

  During zinc vapor supply, since zinc is in a boiling state, the zinc liquid level 23 may fluctuate so as to wave. Therefore, when the zinc liquid level 23 fluctuates so as to wave, for example, the distance is measured 10 times per second, and the control means 6 is made to take in the value of the distance 10 times. The average value of the 10 distance values is calculated, and the calculated average distance is adopted as the distance value representing this one second, and the difference in the distances (at the start of zinc vapor supply-during zinc vapor supply) (At each time of taking in), and when there are one or more peaks in the distribution of the values of the 10 times, the longest value among them is the distance representing this 1 second. You may employ | adopt as a value of. Furthermore, the difference in the distance may be calculated by adopting an average value for 10 seconds of the distance value representing 1 second as the distance value representing 10 seconds. Alternatively, when the measurement is performed 100 times in 10 seconds and there is one or more peaks in the distribution of measurement distances, the average value of the top 1 to 10 distances among them is the distance representative of the 10 seconds. The difference between the distances may be calculated by adopting the above value. Further, the control means 6 can be programmed so that such a calculation is performed.

  The control means 6 is connected to the heater 7 of the zinc evaporator, and the zinc liquid level 23 and the laser beam transmitter / receiver at the start of supply of zinc vapor and at the time of each intake are calculated. Heater of the zinc evaporator so that the height of the zinc liquid level 23 is constant at the height of the zinc liquid level 23 when the supply of zinc vapor starts. 7 outputs an output control signal 21. In other words, based on the difference in the height of the zinc liquid level 23 at the start of supply of zinc vapor and at the time of each intake, the height of the liquid level 23 of zinc is calculated as follows. An output control signal 21 is output to the heater 7 of the zinc evaporator so that the height of the zinc liquid surface 23 is constant. The control means 6 is an electronic computer programmed to output such an output control signal.

  Specifically, when the difference in distance between the start of supply of zinc vapor and each intake is a negative value, that is, the liquid level of zinc is greater at the time of each intake than at the start of supply of zinc vapor. When the height of 23 is low, an output control signal 21 for lowering the output is output to the heater 7 of the zinc evaporator so as to lower the temperature of the zinc evaporator 1, while the supply of zinc vapor is started. When the difference in the distance at each intake is a positive value, that is, when the height of the zinc liquid surface 23 is higher at each intake than at the start of the supply of zinc vapor, the zinc An output control signal 21 for increasing the output is output to the heater 7 of the zinc evaporator so as to raise the temperature of the evaporator 1. In FIG. 1, the transmission path of each signal is indicated by a dotted line.

  Further, the zinc evaporator 1 may be provided with an inert gas supply pipe for making the inside of the zinc evaporator 1 an inert gas atmosphere. In this case, from the inert gas supply pipe, The supplied inert gas moves to the subsequent apparatus through the zinc evaporator 1 and the zinc vapor supply pipe 8. Examples of the inert gas include nitrogen gas, helium gas, neon gas, argon gas, xenon gas, etc. Among these, nitrogen gas is preferable.

  The zinc melter 2 may be provided with an inert gas supply pipe for making the inside of the zinc melter 2 an inert gas atmosphere.

  A method for supplying zinc vapor using the zinc vapor supply device 20 shown in FIG. 1 will be described. First, the zinc evaporator 1 is heated by the heater 7 and the zinc melter 2 is heated by the heater 9 to melt the zinc in the container. Next, the temperature of the zinc evaporator 1 is raised to a temperature equal to or higher than the boiling point of zinc to boil the zinc. From the point of time when the boiling of zinc starts, the granular zinc meter 3 is used to start the supply of granular zinc to the zinc melter 2 and the zinc vapor 10 is discharged from the zinc vapor discharge pipe 8. Then, supply of zinc vapor to the subsequent apparatus is started. Further, using the laser type distance measuring device 17, the height of the zinc liquid surface 23 in the zinc evaporator 1 (the distance between the zinc liquid surface 23 and the laser beam transmitter / receiver 4). ) Measurement is started, and the control means 6 records the value at the start of the supply of zinc vapor.

  Then, using the granular zinc meter 3, the granular zinc is supplied to the zinc melter 2 at a constant supply rate, and the molten zinc is caused to overflow from the zinc melter 2 by the amount of the supplied granular zinc. Thus, while supplying molten zinc to the zinc evaporator 1 at a constant supply rate, the zinc evaporator 1 evaporates zinc and discharges the zinc vapor 10 from the zinc vapor supply pipe 8.

  At this time, using the laser type distance measuring device 17, the height of the zinc liquid surface 23 in the zinc evaporator 1 (the zinc liquid surface 23 and the laser light transmitting / receiving unit 4 Distance) is measured, and based on this value, the height of the zinc liquid surface 23 becomes constant at the height of the zinc liquid surface 23 at the start of supply of zinc vapor. The temperature of the zinc evaporator 1 is adjusted to adjust the evaporation rate of zinc in the zinc evaporator 1.

  In this way, by supplying molten zinc to the zinc evaporator 1 at a constant supply rate, zinc vapor can be supplied to the subsequent apparatus at a constant supply rate. That is, in the zinc vapor supply method of the present invention, the height of the liquid surface 23 of the zinc in the zinc evaporator 1 becomes constant while supplying molten zinc to the zinc evaporator 1 at a constant supply rate. Thus, by evaporating the zinc in the zinc evaporator 1, the supply amount of the molten zinc and the evaporation amount of the zinc vapor become the same. Therefore, in the zinc vapor supply method of the present invention, if the molten zinc supply rate is made constant, zinc vapor can be supplied to the subsequent apparatus at the same constant rate. In addition, when using this zinc vapor supply device 20 in FIG. 1, if the supply rate of granular zinc by the granular zinc meter 3 is made constant, zinc vapor can be supplied at the same constant rate. .

  That is, the zinc vapor supply apparatus of the present invention includes a zinc evaporator, molten zinc supply means for supplying molten zinc to the zinc evaporator at a constant speed, and exhausted evaporated zinc from the zinc evaporator. A non-contact type distance measuring device for measuring a distance between a zinc vapor discharge pipe for measuring the zinc vapor level in the zinc evaporator, and a non-contact type distance measuring device for measuring the distance between the zinc liquid level and the non-contact type distance measuring device The distance level signal is input, the height of the zinc liquid level is calculated from the distance, and an output control signal is output to the heater of the zinc evaporator so that the height of the zinc liquid level is constant. And a zinc vapor supply device.

  The molten zinc supplying means according to the zinc vapor supplying apparatus of the present invention is an overflow type zinc melting apparatus and a constant supply speed to the zinc melting apparatus, like the molten zinc supplying means 25 shown in FIG. A combination with a solid zinc feeder capable of supplying solid zinc is preferable, but the present invention is not limited to this, and it is possible to supply molten zinc to the zinc evaporator 1 at a constant supply rate. If it is.

  The heater of the zinc evaporator according to the zinc vapor supply apparatus of the present invention is not particularly limited, but it is preferable that the response to the output control signal from the control means is fast, and the temperature can be quickly controlled. An electric heater is preferred.

  Further, the zinc vapor supply method of the present invention is a zinc vapor supply method in which the molten zinc is supplied to the zinc evaporator, while the evaporated zinc vapor is discharged from the zinc evaporator and supplied to the subsequent apparatus. While the molten zinc is supplied to the zinc evaporator at a constant supply rate, the height of the zinc liquid level in the zinc evaporator is measured so that the zinc liquid level becomes constant. The zinc vapor supply method is characterized by evaporating zinc in the zinc evaporator.

  In the zinc vapor supply method of the present invention, a non-contact distance measuring device is installed above the zinc liquid surface in the zinc evaporator, and the zinc liquid surface and the non-contact distance measuring device are It is preferable to measure the height of the zinc liquid level in the zinc evaporator by measuring the distance.

  Examples of the non-contact type distance measuring device according to the zinc vapor supply device of the present invention and the zinc vapor supply method of the present invention include the laser type distance measuring device 17 shown in FIG. It is not limited, and any non-contact type distance measuring device capable of measuring the distance from the zinc liquid surface 23 in a non-contact type may be used. Other examples of the non-contact type distance measuring device include devices such as an ultrasonic method, an infrared method, a high frequency method, a differential pressure method, and an image processing method.

  The non-contact type distance measuring device includes a laser beam generator that generates a laser beam for distance measurement modulated at a predetermined modulation frequency, and a laser beam transmitter that transmits the laser beam for measurement toward a measurement point. A light receiving unit that receives reflected light reflected from the measurement point, a phase difference detection unit that detects a phase difference between the reflected light and the laser beam for measurement, and the measurement target from the phase difference A laser-type distance measuring device having a calculation unit for calculating the distance to the point is preferable.

In the present invention, the laser beam modulated at a predetermined modulation frequency is a laser beam modulated with a sine wave of an arbitrary frequency, and the oscillation wavelength is preferably 1060 nm or 1310 nm. In addition, to detect the phase difference between the reflected light and the measurement laser light, a reference light branched from the same light source is prepared separately from the measurement laser light continuously irradiated toward the measurement point. The phase difference between the reference light and the reflected light reflected from the measurement point is added to the phase detector, and the difference output is integrated to detect the phase difference. Further, the distance from the phase difference to the measured point is “C: speed of light (km / s), f: modulation frequency (MHz), Δφ: phase (degree), ΔL: distance to the measured point. For example, when the modulation frequency f is 700 MHz, it is calculated by the following calculation formula.
ΔL = (((C / f) × Δφ) / 2) / 360
= (((300,000 / 700) × Δφ) / 2) / 360
= 0.595 x Δφ
If there is a resolution of 1/3 as the phase detection capability, the distance resolution is 0.198 mm.

  Examples of the laser-type distance measuring device include laser types described in JP-A-2009-198477, JP-A-2004-507742, JP-A-7-35861, JP-A-6-138231, and the like. A distance measuring device is mentioned.

  The device for supplying zinc vapor according to the zinc vapor supply device of the present invention and the zinc vapor supply method of the present invention is not particularly limited as long as it is a device using zinc vapor, for example, silicon tetrachloride vapor and A reaction furnace to which zinc vapor is supplied, for producing polycrystalline silicon such that silicon tetrachloride vapor reacts with zinc vapor in the reaction furnace, and polycrystalline silicon is deposited in the reaction furnace. A reaction furnace is mentioned. Other examples include an apparatus for producing zinc white (zinc oxide) in which zinc vapor reacts with oxygen.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

Example 1
Using the zinc vapor supply device 20 shown in FIG. 1, zinc vapor was supplied as follows.
<Startup>
The temperature setting of the zinc evaporator 1 was set to 950 ° C., the temperature setting of the zinc melter 2 was set to 700 ° C., nitrogen was supplied into the zinc evaporator 1 and the zinc melter 2 to form a nitrogen atmosphere, and heating was started. .
<Supply of molten zinc>
From the time when the temperature of both the zinc evaporator 1 and the zinc melter 2 is 500 ° C. or more, the granular zinc meter 3 measures 50 g of granular zinc every minute and supplies it to the zinc melter 2. The overflowing molten zinc was supplied to the zinc evaporator 1. At this time, the supply rate of the molten zinc which overflows from the zinc melter 2 and is supplied to the zinc evaporator 1 is 50 g / min. Note that nitrogen was continuously supplied into the zinc evaporator 1 and the zinc melter 2 to form a nitrogen atmosphere.
<Measurement of zinc liquid level>
The height of the zinc liquid level 23 when the temperature of the zinc evaporator 1 reaches 950 ° C. is measured, and the value is recorded in the control means 6 as the zinc liquid level 23 at the start of the supply of zinc vapor. I let you. Even after the supply of molten zinc to the zinc evaporator 1 was started, the measurement of the height of the zinc liquid surface 23 was continued as it was.
<Control of zinc liquid level>
The output of the heater of the zinc evaporator was controlled by the control means 6 so that the height of the zinc liquid level 23 became constant at the height of the zinc liquid level 23 at the start of supply of zinc vapor.
<Laser type distance measuring instrument 17>
Presize gauge frequency: 700MHz
Beam diameter: 2mm
Separation capacity: 0.15mm
Measurement: 1 time / 0.1 seconds

  Zinc vapor was supplied for 40 hours as described above. Meanwhile, the height of the zinc liquid surface 23 was kept constant, and the temperature of zinc in the zinc evaporator 1 was 950 ° C.

  Next, the supply rate of granular zinc was changed from 50 g per minute to 70 g per minute, and the supply of zinc vapor was continued. As a result, the height of the zinc liquid surface temporarily increased, but thereafter kept constant. At this time, the temperature of zinc in the zinc evaporator 1 was 964 ° C.

  According to the present invention, since zinc vapor can be supplied at a constant supply rate, a production process using zinc vapor, for example, a production process of polycrystalline silicon by a zinc reduction method can be stably performed.

DESCRIPTION OF SYMBOLS 1 Zinc evaporator 2 Zinc melter 3 Granular zinc metering device 4 Laser light transmission part and light receiving part 5 Phase difference detection part 6 Control means 7 Zinc evaporator heater 8 Zinc vapor discharge pipe 9 Zinc melter heater 10 Zinc Steam 11 Granular zinc supply part 12 Overflow pipe 15 Zinc 16 Molten zinc 17 Laser type distance measuring device 18 Laser light generation part 19 Distance signal 20 Zinc vapor supply device 21 Output control signal 22 Calculation part 23 Zinc liquid level 24 Granular zinc Supply pipe 25 Molten zinc supply means 26 Phase difference signal

Claims (3)

  In the method of supplying zinc vapor, the molten zinc is supplied to the zinc evaporator, and the evaporated zinc vapor is discharged from the zinc evaporator and supplied to the subsequent apparatus. In the zinc vapor supply method, the molten zinc is supplied to the zinc evaporator at a constant supply rate. While supplying zinc, the height of the zinc level in the zinc evaporator is measured, and the zinc in the zinc evaporator is evaporated so that the level of the zinc level is constant. A method for supplying zinc vapor.   A zinc evaporator, molten zinc supply means for supplying molten zinc to the zinc evaporator at a constant rate, a zinc vapor discharge pipe for discharging evaporated zinc from the zinc evaporator, and the zinc evaporation A non-contact type distance measuring device for measuring the distance from the zinc liquid level in the vessel, and a distance signal between the zinc liquid level and the non-contact type distance measuring device are input, and the zinc is calculated from the distance. And a control means for outputting an output control signal to a heater of the zinc evaporator so that the height of the liquid level of the zinc is constant and the height of the liquid level of the zinc is constant. Steam supply device.   The non-contact type distance measuring device generates a laser beam for distance measurement modulated at a predetermined modulation frequency, and transmits a laser beam for transmitting the laser beam for measurement toward a measurement point. A light receiving unit that receives reflected light reflected from the measurement point, a phase difference detection unit that detects a phase difference between the reflected light and the measurement laser beam, and the measurement target from the phase difference The apparatus for supplying zinc vapor according to claim 2, wherein the apparatus is a laser-type distance measuring device having a calculation unit for calculating a distance to a point.