阅读说明：本技术 一种用于冻融阀放料的中频感应线圈及其使用方法 (Medium-frequency induction coil for discharging of freeze-thaw valve and use method thereof ) 是由 裴广庆 陈树彬 凡思军 唐景平 钱敏 邹兆松 薛天锋 胡丽丽 于 2021-08-17 设计创作，主要内容包括：本发明涉及核废料玻璃固化领域,具体涉及一种新型中频感应线圈及其使用方法。中频感应线圈分为直筒型和纺锤型；直筒型线圈设置上段、中段和下段,上段和下段铜管间距小于中段；纺锤型线圈设置上段、中段和下段,上段和下段铜管直径小于中段。这两种线圈结构,结合底部水冷闸阀,实现温度梯度可控,放料启动和停止操作简单,可有效避免漏料管内玻璃析晶和底部玻璃拉丝,适合长期服役。(The invention relates to the field of nuclear waste glass solidification, in particular to a novel medium-frequency induction coil and a using method thereof. The medium-frequency induction coil is divided into a straight cylinder type and a spindle type; the straight-tube coil is provided with an upper section, a middle section and a lower section, and the distance between copper tubes of the upper section and the lower section is smaller than that of the middle section; the spindle-shaped coil is provided with an upper section, a middle section and a lower section, and the diameters of copper pipes of the upper section and the lower section are smaller than that of the middle section. The two coil structures are combined with a bottom water-cooling gate valve, so that the temperature gradient is controllable, the starting and stopping operations of discharging are simple, the devitrification of glass in the material leakage pipe and the drawing of bottom glass can be effectively avoided, and the material leakage pipe is suitable for long-term service.)

1. The utility model provides a medium frequency induction coil for freezing and thawing valve blowing, includes hourglass material pipe (1) and winding induction coil (2) on this hourglass material pipe (1), its characterized in that: the induction coil (2) is sequentially divided into an upper section (3), a middle section (4) and a lower section (5) from top to bottom;

and the coil distance I and the coil diameter D of the upper section (3) and the lower section (5) are set, and the coil distance L and the coil diameter D of the middle section (4) meet the following conditions:

l < L or D < D.

2. The medium-frequency induction coil for discharging of a freeze-thaw valve according to claim 1, which is characterized in that: the upper section (3) is close to the crucible bottom, and during discharging, namely during induction heating, the temperature of the material leakage pipe is higher than the liquid phase temperature of glass and lower than 1050 ℃.

3. The medium-frequency induction coil for discharging of a freeze-thaw valve according to claim 1, which is characterized in that: L/L is equal to 1.1-3, preferably 1.5-2.

4. The medium-frequency induction coil for discharging of a freeze-thaw valve according to claim 1, which is characterized in that: the D/D is equal to 1.1-1.5, preferably 1.2-1.3.

5. The use method of the medium frequency induction coil for discharging of the freeze-thaw valve as claimed in any one of claims 1 to 4, wherein: the method comprises the following steps:

step 1, setting a temperature rise program on an intermediate frequency controller, setting the temperature rise rate to be 20-50 ℃/min, and setting the highest temperature to be T_L+50 ℃ wherein, T_LIs the liquidus temperature of the glass;

step 2, starting a discharging process, and starting a medium-frequency heating power supply;

after 3.30-50 min, discharging the glass in the material leaking pipe to the material receiving tank;

step 4, calculating a discharging rate according to a real-time weight signal fed back by the material receiving tank, outputting a power control signal by an intermediate frequency controller, and controlling the viscosity of the molten glass by combining the temperature control of the molten glass in the crucible, wherein the discharging rate is controlled to be 2-8 kg/min;

step 5, slowly reducing the medium-frequency heating power 1-2 min before the weight of the glass receiving tank reaches the target weight, ensuring that molten glass at the lower section of the material leakage pipe is emptied to avoid glass drawing, and still leaving part of solid glass at the upper section and the middle section to realize material blocking;

and 6, when the weight of the glass receiving tank reaches the target weight, closing the intermediate frequency heating, and closing the water-cooling gate valve to finish a round of discharging process.

Technical Field

The invention relates to the field of nuclear waste glass solidification, in particular to a medium-frequency induction coil for discharging of a freeze-thaw valve and a using method thereof.

Background

The main working principle of the medium-frequency induction heating power supply is that three-phase input voltage is rectified into direct current through a rectifier diode, then the direct current is connected to an inverter through an alternating current contactor, finally the medium-frequency alternating current voltage is output to a transformer through an IGBT full-bridge inverter, then alternating current is output to an induction coil, and induced current is generated on a metal material (a material leakage pipe). Therefore, the leakage pipe is a heating body and is also a flow passage of high-temperature melt.

The Chinese atomic energy science research institute discloses a high-temperature melt medium-frequency induction heating discharging device (CN201610478762.1) for a cold crucible, which is relatively simple in structure, is not beneficial to emptying glass near a material leakage port, is easy to generate glass drawing and affects the use reliability of a high-radioactivity environment.

Japanese Doryokuro Kakunenryo Kaihatsu discloses a structure of a cold crucible freeze-thaw valve (US1984/4460398), and the freeze-thaw valve adopts double medium frequency induction heating to realize accurate control of discharging and closing operations. Meanwhile, after the glass remained near the material leakage port before the discharging is closed is heated continuously by the lower intermediate frequency heating, the emptying operation can be completed, so that the high-radioactivity glass wire drawing can be avoided. But the structure is relatively complex and not conducive to remote disassembly and assembly and maintenance.

Meanwhile, how to control the longitudinal temperature gradient of the leakage pipe is an important parameter for completing repeated discharging without causing glass crystallization, and the patents do not relate to the technology.

Disclosure of Invention

In order to overcome the defects of medium-frequency induction heating of the existing leakage pipe, the invention discloses a medium-frequency induction coil applicable to discharging of a freeze-thaw valve and a using method thereof.

The utility model provides a medium frequency induction coil for freezing and thawing valve blowing, includes leaking the material pipe and twines the induction coil on this leaks the material pipe, and its characteristics are characterized in that: the induction coil is sequentially divided into an upper section, a middle section and a lower section from top to bottom;

establish coil interval I, the coil diameter D of upper segment and hypomere, the coil interval L of middle section, coil diameter D, then satisfy the following condition:

l < L or D < D.

The upper section of the coil is close to the bottom of the crucible, and the temperature of the material leaking pipe at the position during material discharging (during induction heating) is higher than the liquid phase temperature T of glass_LBut should not exceed the long-term reliable working temperature of the leakage pipe, generally below 1050 ℃, and optimally below 1000 ℃.

Furthermore, the middle section of the coil is the central part of the coil, and the temperature of the material leakage pipe at the position is relatively low when the material is discharged, but the temperature of the material leakage pipe gradually approaches the temperature of the upper section due to the heat transfer effect of the material leakage pipe along with the time. After the emptying is finished, the temperature at the position can be rapidly reduced, the viscosity of the high-temperature glass is rapidly increased, and the material blocking is realized.

Further, the lower section of the coil is the lowest part of the coil and is close to the discharge hole of the leakage pipe. Before discharging is finished, the heating power of the coil is slowly reduced, the temperature at the position can be reduced and is still higher than the upper limit temperature of devitrification of glass, the high-temperature glass at the position can be emptied, and glass drawing is avoided.

Furthermore, the lower section of the coil is optimally the leakage pipe which leaks 1-3 cm. The leakage is too much, the temperature at the position is lower than that of the position where the coil covers the material leakage pipe due to the rapid heat dissipation of the discharge port, if the temperature is lower than the liquid phase temperature of glass for a long time, the glass is crystallized, and the material leakage port is blocked after the material is discharged for many times, so that the material discharging failure is caused.

Further, the ratio L/L of the coil space L of the middle section of the straight-tube coil to the coil space L of the upper section and the lower section of the straight-tube coil is equal to 1.1-3, and the optimal ratio is 1.5-2. The proportion is too large, the temperature gradient of the material leakage pipe is large, the material leakage is difficult to control, and the crystallization temperature control during material discharging is difficult to realize; the proportion is too small, the temperature gradient of the material leakage pipe is small, and the rapid material blocking and the glass drawing during material discharging can not be realized.

The ratio D/D of the coil diameter D of the middle section of the spindle-shaped coil to the coil diameters D of the upper section and the lower section of the spindle-shaped coil is equal to 1.1-1.5, and the optimal ratio is 1.2-1.3. The proportion is too large, the temperature gradient of the material leakage pipe is large, the material leakage is difficult to control, and the crystallization temperature control during material discharging is difficult to realize; the proportion is too small, the temperature gradient of the material leakage pipe is small, and the rapid material blocking and the glass drawing during material discharging can not be realized.

The water-cooling gate valve is an automatic switch valve which is filled with cooling water, the valve is opened during discharging, and the valve is automatically closed after discharging is finished, so that quick discharging is completed.

The use method of the medium-frequency induction coil for discharging the freeze-thaw valve is characterized by comprising the following steps: the method comprises the following steps:

step 1, setting a temperature rise program on an intermediate frequency controller, setting the temperature rise rate to be 20-50 ℃/min, and setting the highest temperature to be T_L+50 ℃ wherein, T_LIs the liquidus temperature of the glass;

step 2, starting a discharging process, and starting a medium-frequency heating power supply;

after 3.30-50 min, discharging the glass in the material leaking pipe to the material receiving tank;

step 4, calculating a discharging rate according to a real-time weight signal fed back by the material receiving tank, outputting a power control signal by an intermediate frequency controller, and controlling the viscosity of the molten glass by combining the temperature control of the molten glass in the crucible, wherein the discharging rate is controlled to be 2-8 kg/min;

step 5, slowly reducing the medium-frequency heating power 1-2 min before the weight of the glass receiving tank reaches the target weight, ensuring that molten glass at the lower section of the material leakage pipe is emptied to avoid glass drawing, and still leaving part of solid glass at the upper section and the middle section to realize material blocking;

and 6, when the weight of the glass receiving tank reaches the target weight, closing the intermediate frequency heating, and closing the water-cooling gate valve to finish a round of discharging process.

The two coil structures are combined with the bottom water-cooling gate valve, so that the temperature gradient is controllable, the material discharging starting and stopping operations are simple, and the bottom wire drawing can be effectively avoided. Specifically, the method comprises the following steps: for the straight-tube coil, when discharging (heating), because the coils of the upper section and the lower section of the leakage pipe are arranged more densely and the magnetic induction intensity is higher, the temperature of the upper section and the lower section of the leakage pipe is higher than that of the middle section, the straight-tube coil can not only quickly transfer heat to solid glass at the top end of the leakage pipe (near the bottom of a crucible), but also prevent the crystallization of the glass caused by the low temperature of the lower end of the leakage pipe in the discharging process; when the glass is closed (cooled), the temperature of the middle section of the leaking pipe is lower than the temperature of the upper section and the lower section, the viscosity of the glass at the position is gradually increased, the middle section glass can be quickly cooled to complete material blocking, residual glass liquid at the lower end of the leaking pipe can be emptied, and glass drawing is avoided.

Compared with the prior art, the invention has the beneficial effects that:

(1) the intermediate frequency induction coil of the device is designed into a segmented structure, the distance between the upper section and the lower section of the straight cylinder is smaller than that of the middle section, the optimal temperature gradient can be realized during heating, high-temperature glass crystallization is avoided during starting, and quick material blocking and glass drawing are avoided during closing;

(2) the medium-frequency induction coil of the device is designed to be of a segmented structure, the diameters of the upper section and the lower section of the spindle are smaller than that of the middle section, the optimal temperature gradient can be realized during heating, high-temperature glass crystallization is avoided during starting, and quick material blocking and glass wire drawing are avoided during closing.

Drawings

Fig. 1 is a schematic structural diagram of a straight-tube coil according to a first embodiment of the mid-frequency induction coil structure of the present invention.

Fig. 2 is a schematic structural diagram of a spindle-type coil according to a second embodiment of the mid-frequency induction coil structure of the present invention.

In the figure: 1-a material leakage pipe; 2-an induction coil; 3-upper section; 4-middle section; 5, a lower section; 6-water-cooled gate valve.

Detailed Description

The invention will be further described with reference to the following examples and the accompanying drawings, without limiting the scope of protection.

Example 1: a straight-tube coil (as shown in fig. 1), wherein the coil distance L between the upper section 3 and the lower section 5 is smaller than the coil distance L between the middle section 4;

690 alloy leakage pipe with the outer diameter of 40mm and the inner diameter of 1 is selected6mm and a total length of 170 mm. The total length of the straight tube type intermediate frequency coil is 100mm, the coil length L of the upper section and the lower section is designed to be 36mm, the middle section length L is designed to be 28mm (L/L ≈ 1.3), and the inner diameter is 60 mm. Selecting a liquid phase temperature T_LIs 900 ℃ borosilicate glass.

The discharging method of the high-temperature glass comprises the following steps:

(1) setting a temperature rise program on an intermediate frequency controller, wherein the temperature rise rate is set to be 40 ℃/min, and the highest temperature is 950 ℃;

(2) starting a discharging flow, and starting a medium-frequency heating power supply;

(3) after 40min, the glass in the material leaking pipe begins to be discharged to the material receiving tank;

(4) calculating a discharging speed according to a real-time weight signal fed back by the material receiving tank, wherein the discharging speed is controlled to be 4 kg/min;

(5) when the weight of the glass receiving tank reaches the target weight, slowly reducing the medium-frequency heating power for 2 min;

(6) and when the weight of the glass receiving tank reaches the target weight, closing the intermediate frequency heating, and closing the water-cooling gate valve to finish a round of discharging process.

When in use, the flow rate of the high-temperature glass in the material leaking pipe is stable, and the influence on the flow rate due to crystallization is avoided; when the material is discharged, the material can be blocked within a few minutes, and the glass drawing does not occur at the material leakage port.

Example 2: spindle type coils (as shown in fig. 2), i.e. the upper and lower coil diameters D are smaller than the middle coil diameter D.

690 alloy leakage pipe is selected, the outer diameter is 45mm, the inner diameter is 16mm, and the total length is 180 mm. The total length of the spindle type intermediate frequency coil is 120mm, the diameter D of the upper section coil and the lower section coil is 65mm, the diameter of the middle section coil is 78mm (D/D is 1.2), and the length of the upper section, the middle section and the lower section are 40 mm. Selecting a liquid phase temperature T_LIs 900 ℃ borosilicate glass.

The discharging method of the high-temperature glass comprises the following steps:

(1) setting a temperature rise program on an intermediate frequency controller, wherein the temperature rise rate is set to be 40 ℃/min, and the highest temperature is 930 ℃;

(2) starting a discharging flow, and starting a medium-frequency heating power supply;

(3) after 35min, the glass in the material leaking pipe begins to be discharged to the material receiving tank;

(4) calculating a discharging speed according to a real-time weight signal fed back by the material receiving tank, wherein the discharging speed is controlled to be 3.5 kg/min;

(5) when the weight of the glass receiving tank reaches the target weight, the medium-frequency heating power is slowly reduced for 1.5 min;

(6) and when the weight of the glass receiving tank reaches the target weight, closing the intermediate frequency heating, and closing the water-cooling gate valve to finish a round of discharging process.

When in use, the flow rate of the high-temperature glass in the material leaking pipe is stable, and the influence on the flow rate due to crystallization does not occur; when the material is closed, the material can be blocked in several minutes, and the glass drawing does not occur at the material leakage port.