Blanking rate stability online monitoring method and device and application thereof

Abstract

The invention relates to a blanking rate stability on-line monitoring method and device and application of the blanking rate stability on-line monitoring device, and the on-line monitoring device comprises a blanking device which can convey raw materials to manufacturing equipment; the speed measuring device can acquire data of the blanking rate and transmit the data of the blanking rate to the online control system; the online adjusting device can act on the discharging device to adjust and control the discharging speed, and information of the current operation state of the online adjusting device is transmitted to the online control system; and the on-line control system can control the on-line adjusting device and / or the real-time discharging device to regulate and control the discharging speed according to the data of the discharging speed and the information of the current operation state of the on-line adjusting device. According to the online monitoring device for the stability of the blanking rate, the blanking rate can be remotely monitored and controlled in real time, the stability of the blanking rate is kept, and the product quality and the production efficiency are improved.

Description

Technical Field

[0001] The invention relates to an online monitoring technology, and in particular to an online monitoring method and device for the stability of a material feeding rate and application thereof. Background Art

[0002] Quartz glass is a special functional material composed of a single component of silicon dioxide. Due to its physical and chemical properties that cannot be replaced by other materials, it plays an indispensable role in the fields of modern information industry, aerospace, optics, photovoltaics, semiconductors and other national strategic emerging industries. With the wide application of quartz glass in optics, electronics, semiconductors and other fields, the quality requirements for quartz glass are getting higher and higher.

[0003] Quartz sand is an important raw material for preparing quartz glass. In the traditional preparation process, quartz sand is prone to incomplete and uneven melting, resulting in defects such as bubbles, spots, and stripes in the quartz glass, which seriously affects the quality of the quartz glass.

[0004] Therefore, how to further improve the quality of quartz glass is very important. Summary of the invention

[0005] The main purpose of the present invention is to provide an online monitoring method, device and application of the stability of material feeding rate. The technical problem to be solved is how to improve the stability of material feeding rate and thus improve the quality of the product, so as to make it more suitable for practical use.

[0006] The purpose of the present invention and the technical problem to be solved are achieved by adopting the following technical solutions. According to the present invention, an online monitoring device for the stability of material feeding rate is provided, which comprises:

[0007] A material unloading device, the aforementioned material unloading device receives the operating parameters input by the online control system and executes the instruction of conveying raw materials;

[0008] A speed measuring device, the speed measuring device can obtain data of the material feeding rate and transmit the data of the material feeding rate to the online control system;

[0009] An online regulating device, wherein the online regulating device can regulate the material discharging rate by acting on the material discharging device, and transmit information on the current operating state of the online regulating device to the online control system; and

[0010] The aforementioned online control system can control the aforementioned online adjustment device and / or the aforementioned material discharge device to regulate the aforementioned material discharge rate according to the aforementioned material discharge rate data and the information of the current operating status of the aforementioned online adjustment device.

[0011] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0012] Preferably, in the aforementioned online monitoring device for material unloading rate stability, the material unloading device comprises a material storage bin, the aforementioned speed measuring device comprises a gravity sensor, and the aforementioned gravity sensor is arranged at the bottom of the aforementioned material storage bin.

[0013] Preferably, the above-mentioned unloading rate stability online monitoring device, wherein the unloading device comprises a unloading pipe, a feeder and a storage bin, the above-mentioned unloading pipe connects the above-mentioned storage bin and the above-mentioned feeder; and,

[0014] The aforementioned online adjustment device comprises a vibrator, and the aforementioned vibrator is installed outside the aforementioned material discharge pipe. The aforementioned material discharge rate can be regulated by adjusting the vibration frequency and / or vibration amplitude of the aforementioned vibrator.

[0015] Preferably, in the aforementioned online monitoring device for feeding rate stability, the functional relationship between the feeding rate and the vibration frequency of the aforementioned vibrator is as follows:

[0016]

[0017] Wherein, v is the aforementioned feeding rate, in g / min;

[0018] f is the vibration frequency of the aforementioned vibrator, in Hz.

[0019] Preferably, the above-mentioned online monitoring device for the stability of material feeding rate, wherein the above-mentioned material feeding device comprises a feeder and an air delivery pipe, wherein the above-mentioned air delivery pipe transmits a carrier gas and is connected to the above-mentioned feeder; and

[0020] The aforementioned online regulating device comprises a gas flow controller, and the aforementioned gas flow controller can regulate the aforementioned material discharge rate by adjusting the flow rate of the aforementioned carrier gas.

[0021] Preferably, in the above-mentioned online monitoring device for the stability of the material feeding rate, the functional relationship between the material feeding rate and the flow rate of the above-mentioned carrier gas is as follows:

[0022]

[0023] Wherein, v is the aforementioned feeding rate, in g / min;

[0024] Q is the flow rate of the aforementioned carrier gas, and its unit is L / min.

[0025] Preferably, in the aforementioned online monitoring device for material unloading rate stability, the online control system regulates the material unloading rate by controlling the feeding motor of the aforementioned material unloading device.

[0026] Preferably, the aforementioned online monitoring device for the stability of the material discharge rate, wherein the aforementioned stability online control system includes a monitoring control center and a PLC controller, and the aforementioned monitoring control center is connected to the aforementioned online adjustment device and the aforementioned material discharge device through the PLC controller.

[0027] The purpose of the present invention and the technical problem solved by the present invention are also achieved by adopting the following technical solutions. According to a method for online monitoring of the stability of a material feeding rate proposed by the present invention, the steps include:

[0028] (1) The unloading device receives the operating parameters input by the online control system and executes the instructions for conveying raw materials;

[0029] (2) The speed measuring device monitors the real-time feeding rate of the raw materials and transmits the obtained real-time parameters to the aforementioned online control system;

[0030] (3) the online adjustment device transmits the current operating status data information to the aforementioned online control system; and,

[0031] (4) The aforementioned online control system substitutes the acquired data information into the formula for data calculation, compares the calculated result with the judgment value, and obtains the adjustment parameter that satisfies the system input value. The aforementioned online control system controls the aforementioned online regulating device and the aforementioned unloading device according to the adjustment parameter, and regulates the unloading rate to keep the unloading rate stable.

[0032] The purpose of the present invention and the technical problems solved therein are also achieved by adopting the following technical solutions: The present invention proposes the application of any of the above-mentioned online monitoring devices for feeding rate stability in the field of quartz glass preparation.

[0033] By means of the above technical solution, the method, device and application of online monitoring of material feeding rate stability of the present invention have at least the following advantages:

[0034] The object of the present invention is to provide an online monitoring device for the stability of a material feeding rate. After the online control system obtains the material feeding rate, it controls the online regulating device and / or the material feeding device, wherein the online regulating device acts on the material feeding device to achieve real-time regulation of the material feeding rate. The online monitoring device for the stability of a material feeding rate of the present invention can achieve remote real-time monitoring and control of the material feeding rate, maintain the stability of the material feeding rate, avoid blocking and breaking of the material during the material feeding process, and thus improve product quality and production efficiency.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of an online monitoring device for material feeding rate stability disclosed in some embodiments of the present invention.

[0037] Description of reference numerals:

[0038] 1. Feeding device; 2. Speed ​​measuring device; 3. Online adjustment device; 4. Online control system; 11. Storage bin; 12. Feeding pipe; 13. Feeder; 14. Feeding pipe; 15. Air pipe; 16. Rotating motor. DETAILED DESCRIPTION

[0039] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the method and device for online monitoring of the stability of the material feeding rate proposed by the present invention, its specific implementation, structure, features and effects thereof, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0040] The present invention proposes an online monitoring device for material feeding rate stability, such as Figure 1 As shown, it includes:

[0041] The unloading device 1 receives the operating parameters input by the online control system 4 and executes the instruction of conveying raw materials;

[0042] The speed measuring device 2 can obtain the data of the material feeding rate and transmit the data of the material feeding rate to the online control system 4;

[0043] An online regulating device 3, wherein the online regulating device 3 can regulate the material discharging rate by acting on the material discharging device 1, and transmit information on the current operating state of the online regulating device 3 to the online control system 4; and,

[0044] The aforementioned online control system 4 can control the aforementioned online regulating device 3 and / or the aforementioned unloading device 1 to regulate the aforementioned unloading rate according to the aforementioned unloading rate data and the information of the current operating status of the aforementioned online regulating device 3.

[0045] Specifically, the unloading device 1 receives the operating parameters input by the online control system 4, executes the instruction of conveying raw materials, and conveys the raw materials to the manufacturing equipment. For example, the unloading device 1 includes a storage bin 11, a unloading pipe 12, a feeder 13, a rotating motor 16, a feeder pipe 14 and an air supply pipe 15. The storage bin 11 is connected to the feeder 13 through the unloading pipe 12, the upper end of the feeder 13 is connected to the bottom end of the unloading pipe 12, the lower end of the feeder 13 is respectively connected to the feeder pipe 14 and the air supply pipe 15, and the feeder 13 is connected to the rotating motor 16. The storage bin 11 and the feeder 13 can be made of polytetrafluoro polymer material; the unloading pipe 12, the feeder pipe 14 and the air supply pipe 15 can be made of PVC material.

[0046] The online monitoring device for material feeding rate stability of the present invention can realize remote real-time monitoring and control of the material feeding rate, timely adjust the material feeding rate, maintain the stability of the material feeding rate, avoid material blockage and material breakage during the material feeding process, and thus improve product quality and production efficiency.

[0047] Preferably, in the aforementioned online monitoring device for material feeding rate stability, the material feeding device 1 comprises a material storage bin 11, the aforementioned speed measuring device 2 comprises a gravity sensor, and the aforementioned gravity sensor is arranged at the bottom of the aforementioned material storage bin 11. Specifically, the gravity sensor can be installed on a fixed frame on the material storage bin 11.

[0048] Preferably, the aforementioned online monitoring device for the stability of the material discharge rate, wherein the material discharge device 1 comprises a material discharge pipe 12, a feeder 13 and a storage bin 11, the aforementioned material discharge pipe 12 connects the aforementioned storage bin 11 and the aforementioned feeder 13; and the aforementioned online adjustment device 3 comprises a vibrator, the aforementioned vibrator is installed on the outside of the aforementioned material discharge pipe 12, and the aforementioned material discharge rate can be regulated by adjusting the vibration frequency and / or vibration amplitude of the aforementioned vibrator.

[0049] Preferably, in the aforementioned online monitoring device for feeding rate stability, the functional relationship between the feeding rate and the vibration frequency of the aforementioned vibrator is as follows:

[0050]

[0051] Wherein, v is the aforementioned feeding rate, in g / min;

[0052] f is the vibration frequency of the aforementioned vibrator, in Hz.

[0053] Specifically, the experimental data of the material feeding rate and the vibration frequency of the vibrator were collected and sorted, and the above functional relationship was established through curve fitting analysis.

[0054] Preferably, the aforementioned unloading rate stability online monitoring device, wherein the unloading device 1 includes a feeder 13 and an air supply pipe 15, wherein the air supply pipe 15 transmits a carrier gas and is connected to the aforementioned feeder 13; and the aforementioned online regulating device 3 includes a gas flow controller, which can adjust the unloading rate by adjusting the flow of the aforementioned carrier gas. Specifically, the gas flow controller can be a gas flow meter, which passes the carrier gas into the feeder 13 through the air supply pipe 15 and can adjust the flow of the carrier gas.

[0055] Preferably, in the above-mentioned online monitoring device for the stability of the material feeding rate, the functional relationship between the material feeding rate and the flow rate of the above-mentioned carrier gas is as follows:

[0056]

[0057] Wherein, v is the aforementioned feeding rate, in g / min;

[0058] Q is the flow rate of the aforementioned carrier gas, and its unit is L / min.

[0059] Specifically, the experimental data of the material feeding rate and the carrier gas flow rate were collected and sorted, and the above functional relationship was established through curve fitting analysis.

[0060] Preferably, in the aforementioned online monitoring device for material unloading rate stability, the online control system 4 regulates the material unloading rate by controlling the feeding motor of the aforementioned material unloading device 1 .

[0061] Preferably, the aforementioned online monitoring device for the stability of the material feeding rate, wherein the stability online control system 4 includes a monitoring control center and a PLC controller, and the aforementioned monitoring control center is connected to the aforementioned online adjustment device 3 and the aforementioned material feeding device 1 through the PLC controller. Specifically, the PLC controller (Programmable Logic Controller) refers to a programmable logic controller, which is a digital operation controller with a microprocessor for automatic control, and can load control instructions into the memory at any time for storage and execution. For example, the monitoring control center is connected to the vibrator, the gas flow meter, and the rotating motor 16 through the PLC controller to control the vibration frequency of the vibrator, the carrier gas flow rate, and the feeder 13 to monitor the material feeding rate.

[0062] The present invention provides a method for online monitoring of material feeding rate stability, the steps of which include:

[0063] (1) The unloading device 1 receives the operating parameters input by the online control system 4 and executes the instruction of conveying raw materials;

[0064] (2) The speed measuring device 2 monitors the real-time feeding rate of the raw materials and transmits the acquired real-time parameters to the aforementioned online control system 4;

[0065] (3) the online regulating device 3 transmits the current operating status data information to the aforementioned online control system 4; and,

[0066] (4) The aforementioned online control system 4 substitutes the acquired data information into the formula to perform data calculation, compares the calculated result with the judgment value, and obtains the adjustment parameter that satisfies the system input value. The aforementioned online control system 4 controls the aforementioned online regulating device 3 and the aforementioned unloading device 1 according to the adjustment parameter, and regulates the unloading rate to keep the unloading rate stable.

[0067] The present invention proposes the application of any of the above-mentioned online monitoring devices for feeding rate stability in the field of quartz glass preparation. Quartz glass is prepared using quartz sand as raw material. The online monitoring device for feeding rate stability provided by the present invention is used to monitor and control the feeding rate of quartz sand in real time, so that the feeding rate of quartz sand is kept stable, so that the quartz sand is melted completely and evenly during the preparation process, and defects such as bubbles, spots, and stripes are avoided in the quartz glass, thereby improving the quality of the quartz glass.

[0068] The present invention will be further described below in conjunction with specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0069] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well known to those skilled in the art; unless otherwise specified, the methods described are all methods well known in the art. Unless otherwise defined, the technical terms or scientific terms used should have the common meanings understood by ordinary technicians in the field to which the present invention belongs.

[0070] Example 1

[0071] This embodiment provides an online monitoring device for the stability of material feeding rate. Figure 1 shown.

[0072] The online monitoring device for material feeding rate stability includes:

[0073] The material unloading device 1 receives the operation parameters input by the online control system 4, executes the instruction of conveying raw materials, and conveys the raw materials to the manufacturing equipment. The material unloading device 1 includes a storage bin 11, a material unloading pipe 12, a feeder 13, a rotating motor 16, a feeder pipe 14 and an air supply pipe 15. The storage bin 11 is connected to the feeder 13 through the material unloading pipe 12, the upper end of the feeder 13 is connected to the bottom end of the material unloading pipe 12, the lower end of the feeder 13 is respectively connected to the feeder pipe 14 and the air supply pipe 15, and the feeder 13 is connected to the rotating motor 16.

[0074] The speed measuring device 2 obtains the data of the material feeding rate and transmits the data of the material feeding rate to the aforementioned online control system 4. The speed measuring device 2 includes a gravity sensor, which is arranged at the bottom of the storage bin 11 and installed on a fixed frame on the storage bin 11.

[0075] The online regulating device 3 regulates the unloading rate by acting on the unloading device 1, and transmits the information of the current operating state of the online regulating device 3 to the aforementioned online control system 4. The online regulating device 3 includes a vibrator and a gas flow controller. The vibrator is installed on the outside of the unloading pipe 12, and the unloading rate can be regulated by adjusting the vibration frequency and / or vibration amplitude of the vibrator. The gas flow controller can regulate the unloading rate by adjusting the flow rate of the carrier gas in the air supply pipe 15. The gas flow controller is a gas flow meter, and the gas flow meter passes the carrier gas into the feeder 13 through the air supply pipe 15, and can regulate the flow rate of the carrier gas.

[0076] The online control system 4 can control the online regulating device 3 to adjust the material feeding rate according to the material feeding rate data and the information of the current operation state of the online regulating device 3.

[0077] Example 2

[0078] This embodiment provides an application of an online monitoring device for material feeding rate stability and a method for online monitoring of material feeding rate stability.

[0079] This embodiment adopts the online monitoring device for feeding rate stability in embodiment 1. Feeding device 1 receives the quartz sand feeding rate of 61g / min input by the online control system 4, and executes the instruction of conveying quartz sand; speed measuring device 2 monitors the real-time feeding rate of quartz sand in storage bin 11, and displays that the quartz sand feeding rate is 53g / min, and transmits the acquired real-time rate to online control system 4; the current operating status of online regulating device 3 displays that the vibration frequency of the vibrator is 0Hz, and the gas flow rate of the gas flowmeter is 0L / min, and transmits the current operating status data information to online control system 4; online control system 4 receives the real-time feeding rate of quartz sand of 53g / min, and substitutes it into the above formula It is concluded that 0<f<1, which meets the calculation requirements. The online control system 4 continues to perform the calculation and substitutes the input quartz sand feeding rate of 61g / min into the above formula. It is found that when f=2Hz, v=60g / min, which is close to the input quartz sand feeding rate of 61g / min (Δ≤1). The online control system 4 controls the online regulating device 3 to adjust the vibration frequency of the external vibrator of the feeding pipe to 2Hz according to the calculated adjustment parameter (f=2). The speed measuring device 2 measures the quartz sand feeding rate again, showing that the quartz sand feeding rate is 60g / min, and the feeding device resumes stable transportation.

[0080] Example 3

[0081] This embodiment provides an application of an online monitoring device for material feeding rate stability and a method for online monitoring of material feeding rate stability.

[0082] This embodiment adopts the online monitoring device for feeding rate stability in embodiment 1. Feeding device 1 receives the quartz sand feeding rate of 75g / min input by online control system 4, and executes the instruction of conveying quartz sand; speed measuring device 2 monitors the real-time feeding rate of quartz sand in storage bin 11, and displays that the quartz sand feeding rate is 66g / min, and transmits the acquired real-time rate to online control system 4; the current operating status of online regulating device 3 displays that the vibration frequency of the vibrator is 0Hz, and the gas flow rate of the gas flowmeter is 0L / min, and transmits the current operating status data information to online control system 4; online control system 4 receives the real-time feeding rate of quartz sand of 66g / min, and substitutes it into the above formula It is concluded that 3<f<4, which meets the calculation requirements. The online control system 4 continues to perform the calculation and substitutes the input quartz sand feeding rate of 75g / min into the above formula. It is found that when f = 5 Hz, v = 72.8 g / min, which is much different from the input quartz sand feeding rate of 75 g / min (Δ>1), and does not meet the execution requirements. The online control system 4 continues to perform the calculation and substitutes the obtained quartz sand feeding rate v = 72.8 g / min into the above formula. It is concluded that 5<Q<6, which meets the calculation requirements. Line control system 4 continues to perform calculations and substitutes the input quartz sand feeding rate of 75g / min into the above formula. When Q=6L / min, v=74.1g / min, which is close to the input quartz sand feeding rate of 75g / min (Δ≤1). The online control system 4 controls the online regulating device 3 to adjust the vibration frequency of the external vibrator of the feeding pipe to 5Hz and the carrier gas flow rate in the feeder to 6L / min according to the calculated adjustment parameters (f=5; Q=6). The speed measuring device 2 measures the quartz sand feeding rate and shows that the quartz sand feeding rate is 74.1g / min. The feeding device resumes stable transportation.

[0083] It can be seen from Examples 1-3 that the online monitoring device for feeding rate stability provided by the present invention obtains measurement parameters by setting sensors, monitors and controls the feeding rate stability of quartz sand in real time, and monitors key process parameters and quality indicators in real time. It can promptly discover and correct problems in the preparation process, avoid blockage and breakage in the feeding process, improve product quality and production efficiency, realize the automation of online monitoring information processing of feeding rate stability, significantly improve the reliability of the online monitoring and adjustment system, and greatly reduce the workload of engineering personnel.

[0084] In addition, the material feeding rate stability online monitoring device provided by the present invention can also provide data analysis and reporting functions to help enterprises optimize and improve the production process. When the monitoring value exceeds the warning value range, the system will issue a warning in time to prompt the staff to check the operation of the device and the cause of the failure to ensure that the entire system can operate safely and stably.

[0085] The technical features in the claims and / or the specification of the present invention may be combined, and the combination is not limited to the combination obtained by reference in the claims. The technical solution obtained by combining the technical features in the claims and / or the specification is also within the protection scope of the present invention.

[0086] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. An online monitoring device for material feeding rate stability, characterized in that: It includes: A material unloading device, which receives operating parameters input by the online control system and executes instructions for conveying raw materials; A speed measuring device, which can obtain data of material feeding rate and transmit the data of the material feeding rate to the online control system; An online regulating device, which can regulate the material discharge rate by acting on the material discharge device and transmit information about the current operating state of the online regulating device to the online control system; and The online control system can control the online regulating device and / or the unloading device to regulate the unloading rate according to the data of the unloading rate and the information of the current operating state of the online regulating device.

2. The online monitoring device for material feeding rate stability according to claim 1, characterized in that: The feeding device comprises a material storage bin, and the speed measuring device comprises a gravity sensor, and the gravity sensor is arranged at the bottom of the material storage bin.

3. The online monitoring device for material feeding rate stability according to claim 1, characterized in that: The feeding device comprises a feeding pipe, a feeder and a storage bin, wherein the feeding pipe connects the storage bin and the feeder; and The online adjustment device comprises a vibrator, which is installed outside the feeding pipe. The feeding rate can be regulated by adjusting the vibration frequency and / or vibration amplitude of the vibrator.

4. The online monitoring device for material feeding rate stability according to claim 3 is characterized in that: The functional relationship between the material feeding rate and the vibration frequency of the vibrator is as follows: Wherein, v is the feeding rate, in g / min; f is the vibration frequency of the vibrator, in Hz.

5. The online monitoring device for material feeding rate stability according to claim 1, characterized in that: The unloading device comprises a feeder and an air delivery pipe, wherein the air delivery pipe transmits a carrier gas and is connected to the feeder; and, The online regulating device comprises a gas flow controller, and the gas flow controller can regulate the material discharge rate by adjusting the flow rate of the carrier gas.

6. The online monitoring device for material feeding rate stability according to claim 5, characterized in that: The functional relationship between the material discharge rate and the flow rate of the carrier gas is as follows: Wherein, v is the feeding rate, in g / min; Q is the flow rate of the carrier gas, in L / min.

7. The online monitoring device for material feeding rate stability according to claim 1, characterized in that: The online control system regulates the material unloading rate by controlling the feeding motor of the material unloading device.

8. The online monitoring device for material feeding rate stability according to claim 1, characterized in that: The online control system comprises a monitoring control center and a PLC controller, and the monitoring control center is connected to the online regulating device and the unloading device through the PLC controller.

9. A method for online monitoring of material feeding rate stability, characterized in that: The steps include: (1) The unloading device receives the operating parameters input by the online control system and executes the instructions for conveying raw materials; (2) The speed measuring device monitors the real-time feeding rate of the raw materials and transmits the acquired real-time parameters to the online control system; (3) the online adjustment device transmits the current operation status data information to the online control system; and, (4) The online control system substitutes the acquired data information into the formula to perform data calculation, compares the calculated result with the judgment value, and obtains the adjustment parameters that meet the system input value. The online control system controls the online regulating device and the unloading device according to the adjustment parameters, and regulates the unloading rate to keep the unloading rate stable.

10. Application of the online monitoring device for feeding rate stability according to any one of claims 1 to 8 in the field of quartz glass preparation.

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