阅读说明：本技术 热涂镀锌锅液位测量系统及控制方法 (Hot-coating galvanizing pot liquid level measuring system and control method ) 是由 李良洪 李汀瑞 杨芃 何明生 王毅 吕超 王育林 夏念平 于 2020-06-24 设计创作，主要内容包括：本发明公开了一种热涂镀锌锅液位测量系统,包括锌锅、浮动平台、液位测量仪、加锌装置、抽锌泵装置及PLC控制器,所述锌锅内装有锌液；所述浮动平台悬浮于锌液面,且浮动平台上固定有一被测目标物；所述液位测量仪安装在位于锌锅上方的固定支架上,液位测量仪的测量端向下且正对被测目标物；所述加锌装置与锌锅内部连通；所述液位测量仪、加锌装置和抽锌泵装置分别与PLC控制器电连接。本发明还提供了一种热涂镀锌锅液位控制方法。本发明的有益效果为：采用浮动平台作为测量载体,利用浮动平台上的被测目标物的高度变化来显示锌锅内的锌液液位变化,可有效排除锌锅内复杂环境因素的不利影响,提高了锌液液位测量精度。(The invention discloses a liquid level measuring system of a hot-coating galvanizing pot, which comprises a zinc pot, a floating platform, a liquid level measuring instrument, a zinc adding device, a zinc pumping pump device and a PLC (programmable logic controller), wherein zinc liquid is filled in the zinc pot; the floating platform is suspended on the zinc liquid level, and a measured target object is fixed on the floating platform; the liquid level measuring instrument is arranged on a fixed support above the zinc pot, and the measuring end of the liquid level measuring instrument faces downwards and is opposite to a measured target object; the zinc adding device is communicated with the inside of the zinc pot; the liquid level measuring instrument, the zinc adding device and the zinc pumping pump device are respectively and electrically connected with the PLC. The invention also provides a liquid level control method of the hot-coating galvanizing pot. The invention has the beneficial effects that: the floating platform is used as a measuring carrier, and the change of the liquid level of the zinc liquid in the zinc pot is displayed by utilizing the height change of a measured target object on the floating platform, so that the adverse effect of complex environmental factors in the zinc pot can be effectively eliminated, and the measurement precision of the liquid level of the zinc liquid is improved.)

1. A hot coating galvanizing pot liquid level measurement system is characterized by comprising a zinc pot, a floating platform, a liquid level measuring instrument, a zinc adding device, a zinc pumping pump device and a PLC (programmable logic controller), wherein zinc liquid is filled in the zinc pot; the floating platform is suspended on the zinc liquid level, and a measured target object is fixed on the floating platform; the liquid level measuring instrument is arranged on the fixed support above the zinc pot, and the measuring end of the liquid level measuring instrument faces downwards and is opposite to the measured target object and is used for measuring the height of the measured target object; the zinc adding device is communicated with the inside of the zinc pot and is used for adding zinc ingots into the zinc pot; an inlet pipeline of the zinc pumping pump device is connected with an overflow groove in the furnace nose, and an outlet pipeline of the zinc pumping pump device is connected with an external zinc pot; the liquid level measuring instrument, the zinc adding device and the zinc pumping pump device are respectively and electrically connected with the PLC; the liquid level measuring instrument detects the height signal of a measured target object in real time and transmits the height signal to the PLC, the PLC calculates the liquid level variation value h of zinc liquid in the zinc pot according to the height signal of the measured target object, and controls the zinc adding device to automatically add zinc in real time according to the function relation Q between the zinc ingot adding quantity Q and the liquid level variation value h when the set strip steel runs, wherein F (h); meanwhile, the PLC controls the zinc pumping pump device to start zinc pumping according to the set liquid level height in the furnace nose, and zinc ash is discharged out of the strip steel coating area along with zinc liquid overflow.

2. The system for measuring the liquid level of a hot-dip galvanizing pot according to claim 1, wherein the floating platform is an inverted cone-shaped closed cavity, and a measured object is fixed on the upper surface of the floating platform; the buoyancy force of the floating platform in the zinc liquid is larger than the total weight of the floating platform and the measured target.

3. The system for measuring the liquid level of the hot-dip galvanizing pot according to claim 1, wherein the floating platform symmetrically extends outwards from two sides of the lug seat, the lug seat is provided with a guide positioning hole, the guide positioning hole is in sliding fit with a vertically arranged guide rod, and the upper end of the guide rod is arranged on the fixed support.

4. The system of claim 3, wherein the guide positioning hole is in clearance fit with the guide rod.

5. The system for measuring the liquid level of a hot dip galvanizing pot according to claim 3, wherein the guide positioning hole is designed as a blind hole, and the lower end of the blind hole is closed.

6. The system for measuring the liquid level of a hot dip galvanizing pot according to claim 3, wherein a protective sleeve is mounted on the outer peripheral surface of the guide rod.

7. The system for measuring the liquid level of the hot-dip galvanizing pot according to claim 1, wherein the measured object is a steel flat plate, and the radius R of a coverage area is more than or equal to 150 mm; the measured target object is placed at the surface center of the floating platform, and the surface center of the floating platform is collinear with the emission center of the measuring end of the liquid level measuring instrument.

8. The system for measuring the liquid level of the hot-dip galvanizing pot according to claim 1, wherein the liquid level measuring instrument is 1.5 to 2m away from the zinc liquid level; the liquid level measuring instrument is provided with an air cooling protection device or a water cooling protection device.

9. A liquid level control method for a hot-coating galvanizing pot is characterized by comprising the following steps:

step one, providing a liquid level measuring system as claimed in any one of claims 1 to 8 and installing: installing the fixed support, the liquid level measuring instrument, the measured target object and the guide rod in place, placing the floating platform in a zinc pot, and checking whether the floating platform is blocked; the liquid level measuring instrument, the zinc adding device and the zinc pumping pump device are respectively connected with the PLC by related data lines;

step two, switching on a switch of the liquid level measuring instrument to detect the height H of the measured target object before the zinc pot starts to operate₀；

Step three, the strip steel coating begins, namely the liquid level in the zinc pot descends, and the liquid level measuring instrument dynamically measures the height H of the measured target object_t；

Step four, the liquid level measuring instrument inputs the liquid level measuring signal into the PLC controller, and the PLC controller calculates and obtains the liquid level variation value H of the zinc liquid, wherein H is H_t-H₀Controlling a zinc adding device to add zinc ingots into a zinc pot to compensate the consumption of the zinc pot according to the functional relation Q between the zinc ingot adding amount Q and the liquid level variation value h, wherein the functional relation Q is F (h), and the liquid level of the zinc pot is kept stable;

step five, setting a difference value of the main liquid level higher than the overflow liquid level of the furnace nose in the PLC according to the requirement of the coating product on the furnace nose overflow, and controlling the zinc pumping pump device to work according to the maintained liquid level difference; and adjusting the flow of the zinc pumping pump device, keeping the liquid level of the zinc pot higher than the constant value of the overflow liquid level, and discharging zinc ash through overflow of the overflow groove.

Technical Field

The invention relates to the technical field of metallurgical steel rolling, in particular to a hot-coating galvanizing pot liquid level measuring system and a control method.

Background

In the hot galvanizing production process, the accurate control of the liquid level of the zinc pot plays an important role in the hot galvanizing process, and has double significance as an important link of liquid level control, namely zinc pot liquid level measurement. On the one hand, the method provides basis for the zinc adding amount of the zinc pot. The strip steel coating continuously consumes the zinc content in the zinc liquid, and needs to be supplemented by putting zinc ingots into a zinc adding system, and the process is completed by liquid level control. The zinc adding speed (zinc input) is adapted to the absorption capacity (zinc consumption) of the strip steel coating, the strip steel coating takes away zinc in the zinc liquid, the concentration and the liquid level of the zinc liquid can be reduced, and the quantitative data is completed by the liquid level measuring system, so that the zinc adding system is guided to supplement zinc ingots in time, the liquid level of a zinc pot is kept stable, and the zinc plating process is ensured to be carried out smoothly. On the other hand, support is provided for stable overflow of the ash discharging furnace nose. In the existing high-grade hot-dip galvanized strip steel production unit, a furnace operator is internally provided with a zinc ash discharge system, and the ash discharge furnace nose is designed by a zinc liquid overflow thought. The zinc pumping pump device is connected with the zinc ash discharging groove, after the zinc pumping pump device is started, the zinc liquid level in the zinc ash discharging groove is reduced, the zinc liquid in the furnace nose overflows to the zinc ash discharging groove, the zinc ash floating on the surface of the zinc liquid is brought into the zinc ash discharging groove through the overflow of the zinc liquid and is discharged out of the furnace nose along with the zinc pumping pump device, and therefore the influence of the zinc ash on the surface quality of a coating is reduced.

The coating strip steel can continuously consume the zinc liquid in the zinc pot, and in order to keep the liquid level of the zinc pot stable, zinc ingots are required to be continuously added so as to meet the requirements of the galvanizing production process. The zinc adding amount of the zinc adding system is closely related to the accuracy of the zinc liquid level control system, the stability of the liquid level of the zinc pot has great influence on the galvanizing process, and the zinc adding system is required to automatically add zinc according to the tiny change of the liquid level. At present, the liquid level of a zinc pot is directly measured by adopting a liquid level measuring instrument, and the influence of the actual working environment of the zinc pot, such as zinc slag fishing, zinc liquid pumping, strip steel disturbance, equipment vibration and the like, can cause the actual measured value to have large errors, the data measurement fluctuation is large, the production process requirements of high-quality galvanized plates are difficult to meet, the bottleneck restricting the production of high-grade hot galvanized plates is formed, and the quality of galvanized products is hindered from being further improved. Therefore, it is necessary to develop a liquid level measuring system and a control method with high precision and stable performance.

Disclosure of Invention

The invention aims to provide a hot coating liquid level measuring system with high detection precision and stable performance and a control method thereof aiming at the defects of the prior art.

The technical scheme adopted by the invention is as follows: a hot coating galvanizing pot liquid level measuring system comprises a zinc pot, a floating platform, a liquid level measuring instrument, a zinc adding device, a zinc pumping pump device and a PLC (programmable logic controller), wherein zinc liquid is filled in the zinc pot; the floating platform is suspended on the zinc liquid level, and a measured target object is fixed on the floating platform; the liquid level measuring instrument is arranged on the fixed support above the zinc pot, and the measuring end of the liquid level measuring instrument faces downwards and is opposite to the measured target object and is used for measuring the height of the measured target object; the zinc adding device is communicated with the inside of the zinc pot and is used for adding zinc ingots into the zinc pot; an inlet pipeline of the zinc pumping pump device is connected with an overflow groove in the furnace nose, and an outlet pipeline of the zinc pumping pump device is connected with an external zinc pot; the liquid level measuring instrument, the zinc adding device and the zinc pumping pump device are respectively and electrically connected with the PLC; the liquid level measuring instrument detects the height signal of a measured target object in real time and transmits the height signal to the PLC, the PLC calculates the liquid level variation value h of zinc liquid in the zinc pot according to the height signal of the measured target object, and controls the zinc adding device to automatically add zinc in real time according to the function relation Q between the zinc ingot adding quantity Q and the liquid level variation value h when the set strip steel runs, wherein F (h); meanwhile, the PLC controls the zinc pumping pump device to start zinc pumping according to the set liquid level height in the furnace nose, and zinc ash is discharged out of the strip steel coating area along with zinc liquid overflow.

According to the scheme, the floating platform is an inverted cone-shaped closed cavity, and a measured target object is fixed on the upper surface of the floating platform; the buoyancy force of the floating platform in the zinc liquid is larger than the total weight of the floating platform and the measured target.

According to the scheme, the two sides of the floating platform symmetrically extend outwards to form the lug seats, the lug seats are provided with the guide positioning holes, the guide positioning holes are in sliding fit with the vertically arranged guide rods, and the upper ends of the guide rods are installed on the fixed support.

According to the scheme, the guide positioning hole can be in clearance fit with the guide rod.

According to the scheme, the guide positioning hole is designed to be a blind hole, and the lower end of the guide positioning hole is closed.

According to the scheme, the protective sleeve is installed on the outer peripheral surface of the guide rod.

According to the scheme, the measured target is a steel flat plate, and the radius R of a coverage area is more than or equal to 150 mm; the measured target object is placed at the surface center of the floating platform, and the surface center of the floating platform is collinear with the emission center of the measuring end of the liquid level measuring instrument.

According to the scheme, the distance between the liquid level measuring instrument and the zinc liquid level is 1.5-2 m; the liquid level measuring instrument is provided with an air cooling protection device or a water cooling protection device.

The invention also provides a liquid level control method of the hot-coating galvanizing pot, which comprises the following steps:

step one, providing the liquid level measuring system and installing: installing the fixed support, the liquid level measuring instrument, the measured target object and the guide rod in place, placing the floating platform in a zinc pot, and checking whether the floating platform is blocked; the liquid level measuring instrument, the zinc adding device and the zinc pumping pump device are respectively connected with the PLC by related data lines;

step two, switching on a switch of the liquid level measuring instrument to detect the height H of the measured target object before the zinc pot starts to operate₀；

Step three, the strip steel coating begins, namely the liquid level in the zinc pot descends, and the liquid level measuring instrument dynamically measures the height H of the measured target object_t；

Step four, the liquid level measuring instrument inputs the liquid level measuring signal into the PLC controller, and the PLC controller calculates and obtains the liquid level variation value H of the zinc liquid, wherein H is H_t-H₀Controlling a zinc adding device to add zinc ingots into a zinc pot to compensate the consumption of the zinc pot according to the functional relation Q between the zinc ingot adding amount Q and the liquid level variation value h, wherein the functional relation Q is F (h), and the liquid level of the zinc pot is kept stable;

step five, setting a difference value of the main liquid level higher than the overflow liquid level of the furnace nose in the PLC according to the requirement of the coating product on the furnace nose overflow, and controlling the zinc pumping pump device to work according to the maintained liquid level difference; and adjusting the flow of the zinc pumping pump device, keeping the liquid level of the zinc pot higher than the constant value of the overflow liquid level, and discharging zinc ash through overflow of the overflow groove.

The invention has the beneficial effects that: the floating platform is used as a measurement carrier, and the change of the liquid level of the zinc liquid in the zinc pot is displayed by utilizing the height change of a measured target object on the floating platform, so that the adverse effect of complex environmental factors in the zinc pot can be effectively eliminated, the measurement precision of the liquid level of the zinc liquid is improved, and the performance of a measurement system is stable; the zinc liquid level of accurate measurement utilizes PLC controller to realize intelligent zinc and stove nose overflow ash removal, keeps zinc pot steady operation, promotes hot dip galvanized sheet surface quality, has reduced the product and has changed the rate of judgement.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a sectional view a-a of fig. 1.

Wherein, 1, a liquid level measuring instrument; 2. a PLC controller; 3. a floating platform; 4. a zinc adding device; 5. a zinc pumping pump device; 6. a target object to be measured; 7. a guide bar; 8. a protective sleeve; 9. fixing a bracket; 10. a zinc pot.

Detailed Description

For a better understanding of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

As shown in fig. 1 and 2, the liquid level measuring system for the hot-dip galvanizing pot comprises a zinc pot 10, a floating platform 3, a liquid level measuring instrument 1, a zinc adding device 4, a zinc pumping pump device 5 and a PLC controller 2, wherein zinc liquid is filled in the zinc pot 10; the floating platform 3 is suspended on the zinc liquid level, and a measured target object 6 is fixed on the floating platform 3; the liquid level measuring instrument 1 is arranged on a fixed support 9 positioned above a zinc pot 10, the measuring end of the liquid level measuring instrument 1 faces downwards and is opposite to a measured target object 6, and the liquid level measuring instrument is used for monitoring the height of the measured target object (the height variation value of the measured target object 6 is the liquid level variation value of zinc liquid in the zinc pot 10); the zinc adding device 4 is communicated with the interior of the zinc pot 10 and is used for adding zinc ingots into the zinc pot 10; an inlet pipeline of the zinc pumping device 5 is connected with an overflow groove in the furnace nose, and an outlet pipeline of the zinc pumping device 5 is connected with an external zinc pot 10; the liquid level measuring instrument 1, the zinc adding device 4 and the zinc pumping pump device 5 are respectively and electrically connected with the PLC 2. In the invention, a liquid level measuring instrument 1 detects a height signal of a measured target object 6 in real time and transmits the height signal to a PLC (programmable logic controller) 2, the PLC 2 calculates a liquid level variation value h of zinc liquid in a zinc pot 10 according to the height signal of the measured target object 6, and controls a zinc adding device 4 to automatically add zinc in real time according to a set functional relation Q between the zinc ingot adding quantity Q and the liquid level variation value h when strip steel runs, wherein F (h); meanwhile, the PLC 2 controls the zinc pumping pump device 5 to start zinc pumping according to the set liquid level height in the furnace nose (usually, the set liquid level of the zinc pot 10 is 1mm higher than the liquid level of the overflow groove), so that zinc ash is discharged out of the strip steel coating area along with the overflow of zinc liquid.

Preferably, the floating platform 3 is an inverted cone-shaped closed cavity, and the upper surface of the floating platform 3 is fixed with the target object 6 to be measured; the buoyancy force of the floating platform 3 in the zinc liquid is larger than the total weight of the floating platform 3 and the measured target 6. In this embodiment, the floating platform 3 is made of 316L stainless steel metal material, and the main body is a cone-shaped sealed cavity (other sealed cavities with symmetrical structures are also possible). The volume of the sealed cavity is required to satisfy that the buoyancy generated when the floating platform 3 and the object 6 to be measured are put into the zinc liquid is larger than the total weight of the floating platform 3 and the object 6 to be measured, so that the floating platform 3 and the object 6 to be measured can be suspended in the zinc liquid. When the space of the sealed cavity is designed, the buoyancy force of the device immersed in the zinc liquid is larger than the total weight of the floating platform 3 and the measured target 6, and G is less than or equal to gamma V (G is the sum of the mass of the floating platform 3 and the mass of the measured target 6, kg; gamma is the density of the zinc liquid, kg/m)³(ii) a V is sealingVolume of cavity, m³(ii) a The volume of the steel plate immersed in the zinc bath by the floating platform 3 is disregarded).

Preferably, the two sides of the floating platform 3 symmetrically extend outwards to form the ear seats, the ear seats are provided with guide positioning holes, the guide positioning holes are in sliding fit with the guide rods 7 which are vertically arranged, and the upper ends of the guide rods 7 are installed on the fixed support 9. In this embodiment, the guide positioning hole can be in clearance fit with the guide rod 7, and the fit clearance in a thermal state is about 1mm, so that the floating platform 3 can conveniently slide up and down along with the fluctuation of the liquid level of the zinc liquid along the guide rod 7. Preferably, in order to prevent the zinc liquid from being blocked when the zinc liquid is immersed into the guide positioning hole, the guide positioning hole is designed to be a blind hole, and the lower end of the blind hole is closed. Preferably, a protective sleeve 6 is installed on the outer peripheral surface of the guide rod 7 to prevent the guide rod 7 from being damaged by splashing of the metal liquid.

Preferably, the measured target 6 is a steel flat plate, and the radius R of a coverage area is more than or equal to 150 mm; the measured target object 6 is placed at the surface center of the floating platform 3, and the surface center of the floating platform 3 is collinear with the emission center of the measuring end of the liquid level measuring instrument 1.

Preferably, the distance between the liquid level measuring instrument 1 and the zinc liquid level is 1.5-2 m; the liquid level measuring instrument 1 is provided with an air cooling protection device or a water cooling protection device; the liquid level measuring instrument 1 can be a laser liquid level measuring instrument 1 or a radar liquid level measuring instrument 1, and the measuring precision is within the range of +/-1 mm; due to the safety requirement of high-temperature environment, the liquid level measuring instrument 1 has an anti-explosion function.

Preferably, the zinc adding device 4 is arranged at the edge of the zinc pot 10, the zinc adding process is controlled by the PLC 2, and zinc ingots are added into the zinc pot 10 through the conveying mechanism.

The invention provides a liquid level control method of a hot-coating galvanizing kettle 10, which comprises the following steps:

step one, providing and installing the components of the liquid level measuring system: installing a fixed support 9, a liquid level measuring instrument 1, a measured target object 6 and a guide rod 7 in place, placing a floating platform 3 in a zinc pot 10, and checking whether the floating platform 3 is blocked; the liquid level measuring instrument 1, the zinc adding device 4 and the zinc pumping pump device 5 are respectively connected with the PLC 2 by related data lines;

step (ii) ofSecondly, a switch of the liquid level measuring instrument 1 is switched on, and the height H of the measured object 6 before the zinc pot 10 starts to operate is detected₀；

Step three, the strip steel coating begins, namely the liquid level in the zinc pot 10 is reduced, and the liquid level measuring instrument 1 dynamically measures the height H of the measured target object 6_t；

Step four, the liquid level measuring instrument 1 inputs a liquid level measuring signal into the PLC 2, and the PLC 2 calculates and obtains a liquid level variation value H of the zinc liquid, wherein H is H_t-H₀Controlling the zinc adding device 4 to add zinc ingots into the zinc pot 10 to compensate the consumption of the zinc pot 10 according to the functional relation Q between the zinc ingot adding amount Q and the liquid level variation value h, wherein the functional relation Q is F (h), and the liquid level of the zinc pot 10 is kept stable;

step five, setting a difference value of the main liquid level higher than the overflow liquid level of the furnace nose in the PLC controller 2 according to the requirement of the coating product on the furnace nose overflow in the stable control state of the liquid level of the zinc pot 10, and controlling the zinc pumping pump device 5 to work according to the maintained liquid level difference; the flow of the zinc pumping pump device 5 is adjusted, the liquid level of the zinc pot 10 is kept higher than the constant value of the overflow liquid level, the overflow groove stably overflows, and zinc ash in the furnace nose is continuously discharged out of a coating area.

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereto, and although the present invention has been described in detail with reference to the embodiments, it will be apparent to those skilled in the art that modifications can be made to the technical solutions described in the above-mentioned embodiments, or equivalent substitutions of some technical features, but any modifications, equivalents, improvements and the like within the spirit and principle of the present invention shall be included in the protection scope of the present invention.