阅读说明：本技术 一种可变行程打壳气缸 (Variable stroke crust breaking cylinder ) 是由 不公告发明人 于 2020-12-19 设计创作，主要内容包括：一种可变行程打壳气缸是指在传统铝电解槽上使用的打壳下料系统,其中打壳深度可以随着电解槽内融体总高而变化,实现智能控制。从而使锤头打入电解质(甚至铝液)减小,避免长包和锤头过分磨损和热腐蚀。当锤头由于长期使用变短时,可通过自动增加打击深度,确保有效打入槽内锤头深度。(A variable stroke crust breaking cylinder is a crust breaking and blanking system used on a traditional aluminum electrolytic cell, wherein the crust breaking depth can be changed along with the total height of a fused body in the electrolytic cell, and intelligent control is realized. Thereby reducing the electrolyte (even aluminum liquid) injected into the hammer head and avoiding the excessive abrasion and thermal corrosion of the ladle and the hammer head. When the hammer shortens because long-term the use, the accessible increases the strike degree of depth automatically, ensures effectively to strike the interior hammer depth of groove.)

1. The precise control and the automatic depth adjustment control of the crust breaking depth are carried out aiming at the crust breaking cylinder of the aluminum electrolytic cell, and the hardware composition characteristic item is as follows: a special flowmeter is installed on a crust breaking air source on an electrolytic bath, an upper cavity and a lower cavity pressure sensor are installed on each crust breaking cylinder, and executing actions such as crust breaking blanking signals, pressure sensor signals and flowmeter signals are acquired and calculated by adopting an electromagnetic valve group (cylinder end cover integration or split) for cylinder control and an electrical control box is installed on each bath to output the self-adaptive height adjustment of the crust breaking hammer head.

2. The electric control box carries out the acquisition and operation of crust breaking and blanking signals, pressure sensor signals and flowmeter signals to output the self-adaptive height adjustment of the crust breaking hammer head and the like according to the claim 1, wherein the characteristic items of the self-adaptive height adjustment of the crust breaking hammer head are as follows: the crust breaking depth calculation and control method of the crust breaking cylinder comprises the following steps: crust breaking cylinder depth h0=4 meter flow/pi x D2 (upper chamber pressure sensor value).

3. The electric control box carries out the acquisition and operation of crust breaking and blanking signals, pressure sensor signals and flowmeter signals to output the self-adaptive height adjustment of the crust breaking hammer head and the like according to the claim 1, wherein the characteristic items of the self-adaptive height adjustment of the crust breaking hammer head are as follows: the calculation control method for the return stroke height of the crust breaking cylinder comprises the following steps: the return crust breaking cylinder depth h = crust breaking cylinder depth h0-4 meter flow/pi x D2 (upper chamber pressure sensor value).

4. The electric control box carries out the acquisition and operation of crust breaking and blanking signals, pressure sensor signals and flowmeter signals to output the self-adaptive height adjustment of the crust breaking hammer head and the like according to the claim 1, wherein the characteristic items of the self-adaptive height adjustment of the crust breaking hammer head are as follows: according to the requirements of field control, the stroke of an air cylinder is divided into equal divisions of 5 mm-150 mm intervals, the typical value is divided into equal divisions of 10 mm-60 mm intervals, the initial value of the air cylinder is set as a certain crust-breaking depth value, the depth of a hammer head is adjusted in a self-adaptive mode by detecting the pressure change slope (or flow time change slope) of a lower cavity of the crust-breaking air cylinder, when the slope exceeds the normal average slope by more than 10%, the impact depth is adjusted upwards to serve as the reference impact depth, and the specific over-slope value and the up-adjustment depth value are actually determined.

5. The electric control box carries out the acquisition and operation of crust breaking and blanking signals, pressure sensor signals and flowmeter signals to output the self-adaptive height adjustment of the crust breaking hammer head and the like according to the claim 1, wherein the characteristic items of the self-adaptive height adjustment of the crust breaking hammer head are as follows: according to the requirements of field control, the stroke of an air cylinder is divided into equal divisions of 5 mm-150 mm intervals, the typical value is divided into equal divisions of 10 mm-60 mm intervals, the initial value of the air cylinder is set as a certain crust breaking depth value, the depth of a hammer head is adjusted in a self-adaptive mode by detecting the pressure change slope (or the upper cavity flow time change slope) of an upper cavity of a crust breaking air cylinder, when the slope of a certain position exceeds the normal average slope by more than 50%, downward-adjusting striking depth is used as the reference striking depth and material blocking related program control is carried out, and specifically, the exceeding slope value and the downward-adjusting striking.

6. The mounting of upper and lower cavity pressure sensors on each crust breaking cylinder according to claim 1, with possible performance-degrading simplifications, characterized by: only the upper cavity is provided with the pressure sensor, and the lower cavity sensor is cancelled, so that the functions in patent rights 2 and 5 can be realized; the precise positioning function in patent claim 3 is cancelled, and the flow time change slope of the lower cavity is adopted for adjustment in patent claim 4.

7. According to claim 1, an electrical control box is mounted on each tank to collect crust breaking and blanking signals, pressure sensor signals and flowmeter signals and calculate and output self-adaptive height adjustment of the crust breaking hammer head, wherein the electrical control box can be an operation control unit taking a single chip microcomputer, a PLC and the like as a core, can be independently made into a control box, can integrate functions into the tank control box, and can be integrated into a whole through an embedded system structure and a pneumatic control cabinet or a valve block.

Technical Field

Metallurgy of non-ferrous metals.

Background

The aluminum production in the electrolytic aluminum industry in China accounts for about 50 percent of the whole world, and the existing capacity is nearly 3500 million tons. But the key equipment of the electrolytic cell, namely the crust breaking cylinder, is not fully researched at home and abroad. The traditional crust breaking cylinder mainly adopts a whole-course crust breaking mode, and the longer crust breaking time is controlled to ensure that the cylinder can be crust broken in place. Therefore, the cylinder crust breaking hammer is easy to stick to a bag, and is easy to be corroded and abraded by heat. This in turn leads to the following problems: the workload of the inspection personnel of the electrolytic cell is large; the sticking length causes the material to easily drop into the melt of the tank directly, and the effect is caused; the feed opening has large heat dissipation and serious anodic oxidation; short service life of the hammer head and the like. If the crust breaking hammer head of the electrolytic cell can accurately change along with the height of the electrolyte liquid level, the problems can be effectively solved. Revolutionary technological changes will occur.

In recent years, China has raised the research enthusiasm of an intelligent crust breaking and blanking system of an electrolytic cell, but the research is mainly focused on the principle application in the following aspects, and the reliability of the effect is poor. a. Collecting the voltage (or current) of a nucleus body in the electrolytic bath to earth, wherein the force of the doctor is taken as a representative; b. a pressure sensor or a pressure switch is arranged to detect the pneumatic characteristics of the cylinder for control; c. and fixed stroke control is carried out by installing a fixed stroke switch on the end cover. In the above technologies, the class a can theoretically detect that the hammer contacts with electrolyte or aluminum liquid, but because the ideal condition cannot be ensured on site, the detection reliability cannot meet the production and use requirements; in the b-type technology, the operation characteristics of the air cylinder can be judged through pressure curve change or pressure switch characteristic points, and the pressure switch needs to be judged to be operated to the end by combining with an end cover mechanical valve. And c, directly installing a switch valve on the end cover of the cylinder, and judging the in-place condition of the striking cylinder. On the basis of this, rough judgment control is performed in combination with time and other signals. The above methods can not realize the accurate adjustment of the striking hammer head along with the height of the electrolyte liquid level.

Disclosure of Invention

The device is mainly applied to the transformation and new construction of an upper crust breaking and blanking system of an aluminum electrolytic cell, and hardware and software control parts such as a special flowmeter, a cylinder with a pressure sensor, a circuit control panel and the like form hardware. By applying the related technology, the long packing rate of the traditional crust breaking and blanking system is reduced by more than 80%, the material blocking rate is reduced by more than 80%, and the service life of the crust breaking hammer head is prolonged by 3-6 times. The technical effect is very obvious.

For an electrolytic bath crust breaking and blanking system, 3-10 crust breaking and blanking system devices are usually provided, 1-10 special flow sensors (with a typical value of 1-3) can be installed in each bath, 1 each of an upper cavity pressure sensor and a lower cavity pressure sensor is installed in each crust breaking cylinder, and only the upper cavity pressure sensor can be installed. The electrolytic bath crust breaking and blanking control signal, the cylinder pressure sensor signal, the special flowmeter signal and the like are all introduced into the control panel.

When each flowmeter is controlled to bear the crust breaking cylinder to operate independently, accurate control of the air stroke can be achieved. According to the ideal gas correlation equation, the following equation is obtained: the crust breaking stroke calculation formula of the crust breaking cylinder is as follows: crust breaking cylinder depth h0=4 flowmeter flow/pi x D2 (upper chamber pressure sensor value), crust breaking depth determination during return stroke: h0-h =4 × flow count value/pi D2 (lower cavity pressure sensor), crust breaking depth adaptive adjustment: according to the requirements of field control, the stroke of 300mm at the lower part of the cylinder is set to be 10 equal parts, each equal part is 30mm, and the depth of the hammer head is adjusted in a self-adaptive mode through the striking head. When a cylinder out leakage problem occurs, the above calculation will generate deviation, so a leakage detection technology is adopted to determine the leakage of the cylinder. This can be done as follows: detecting the full-pressure leakage of the lower cavity, measuring a flowmeter when the pressure of the lower cavity reaches the system pressure after return stroke, and obtaining the full-pressure leakage data of the lower cavity; and detecting the full-pressure leakage of the upper cavity, wherein the pressure of the upper cavity reaches the system pressure during crust breaking, and the data of the detected flow meter is the full-pressure leakage value of the upper cavity. This data can be used for alarm service or trip corrections.

When detecting that the hammer is stuck, the striking depth of the cylinder is 20mm upwards, and the upward adjustment is not more than 60mm within one hour. The flow rate of the action flowmeter and the value of the pressure sensor at the moment are continuously collected when the crust breaking is carried out on the crust breaking cylinder at a certain point within 2 hours. And calculating the crust breaking depth. When the normal crust breaking depth of the last time is reached, the control system sends an instruction to perform the action of the cylinder return electromagnetic valve. When the cylinder returns, the slope of the accumulated flow and the time of the return flow meter is calculated. Before reaching the highest point, when the slope is more than 10% of the normal slope, the previous reference crust breaking depth is set to be reduced by one unit (the value is set to be within the range of 10 mm-60 mm). Similarly, when the crust breaking cylinder does not reach the bottom, the slope of the upper cavity pressure sensor exceeds the normal value by more than 50% (or the slope pressure value reaches the maximum value of the system), the material blocking control mode is entered, and the standard crust breaking depth before material blocking is increased by one unit (the value in the range of 10 mm-60 mm is set) after the normal operation is carried out. And adjusting or changing the control strategy according to the site by adjusting the crust breaking depth unit each time. And are not discussed in this patent.

Case 1: the electrolytic cell series. There are 6 crust breaking cylinders, 6 alumina blanking cylinders and 2 aluminum fluoride blanking cylinders. And a 1-path gas source main pipe is used for supplying gas for each blanking cylinder on the feeding groove. The flowmeter is arranged on the gas source main pipe, each crust breaking cylinder is provided with a pressure sensor at the upper cavity and the lower cavity), 1 pipe source { (1) can be saved, the spring small force (2) on the single acting cylinder is changed, 2-bit 4-way sensors are used, all the cylinders are controlled by the electromagnetic valve group, and the electric cabinet adopts a single chip microcomputer structure and introduces crust breaking and blanking signals, 12 paths of pressure sensor signals, flowmeter signals and the like of the electrolytic tank control box. And performing crust breaking and blanking actions through related control operation.

Case 2: each electrolytic cell of a certain electrolytic series is provided with 4 crust breaking cylinders, 4 alumina blanking cylinders and 2 aluminum fluoride blanking cylinders. The original alumina and aluminum fluoride are controlled by an electrically controlled 2-position 4-way valve in a pneumatic control box. The electromagnetic switch (stop) valve is changed to carry out blanking through a pneumatic control 2-position 4-way valve on a control gas control groove, and a main gas source of a blanking cylinder is connected through a main gas source pipeline. The original crust breaking cylinder is controlled by a 2-position 5-way air control valve on the crust breaking cylinder on the groove through control air through an electromagnetic switch (stop) valve of an air control box, and the control is changed into single-point control. Each crust breaking cylinder is spaced apart during operation and spaced apart during operation from the blanking cylinder. Therefore, the data of the pressure sensors on the flowmeter and the crust breaking cylinder, crust breaking signals of the cell controller and the like are calculated in the control panel, and the crust breaking position can be adjusted.

Case 3: 7 crust breaking cylinders, 7 alumina blanking cylinders and 1 aluminum fluoride blanking cylinder of an electrolytic cell of an electrolytic series. A flowmeter is arranged on the main gas pipe, and an electric control stop valve is arranged in parallel with the flowmeter. When realizing that the stop valve closes under the single-point crust breaking unloading condition, when realizing the multiple spot crust breaking, can open the stop valve through the electric cabinet.

Case 4: an electrolytic cell of a certain electrolytic series is provided with 8 crust breaking cylinders, 8 alumina blanking cylinders and 2 alumina blanking cylinders, and 2 paths of main air sources for independent air supply are adopted. Each main air source is provided with 1 flowmeter, and 4 crust breaking cylinders, 4 alumina blanking cylinders and 1 aluminum fluoride blanking cylinder are borne. The operation control is carried out by adopting a cylinder valve head and an electromagnetic valve. A pressure sensor is arranged on the upper cavity of each crust breaking cylinder, and 8 paths of pressure sensor signals and 2 paths of flow meter signals are led into an electric control box. And the electric cabinet controls 8 crust breaking cylinders, 8 alumina blanking cylinders and 2 aluminum fluoride blanking cylinders. Accurate striking control of the crust breaking cylinder is carried out on the crust breaking cylinder, self-adaptive height adjustment is carried out, and no long bag or material blockage is ensured.