In the complex network of modern industrial production, hydrocyclone has become an important part of the production process in many industries. From the fine screening of ore in the field of mineral processing, to the coal industry to achieve efficient separation of coal and impurities, and then to the oil industry to help purify crude oil, hydrocyclone by virtue of its unique working principle and excellent performance for the industry’s stable and efficient production to provide a solid guarantee.
In the mineral processing industry, after the ore is mined out, it often contains a variety of different components of minerals, which need to be separated and graded through fine in order to extract valuable metals. Hydrocyclone uses centrifugal force to effectively separate coarse and fine particles in the ore slurry, so that the subsequent beneficiation process can more accurately process ores of different particle sizes. This not only improves the beneficiation efficiency, but also enhances the metal recovery rate and reduces the waste of resources. In the coal industry, coal will be mixed with a large number of impurities and water in the process of mining and transporting, which affects the quality and combustion efficiency of coal. Hydrocyclone can be used in coal washing, desliming and dewatering. In the process of washing, it can separate coal from gangue and other impurities, and improve the purity of coal; in the desliming and dewatering process, it can effectively remove fine particles of impurities and moisture in coal, reduce the ash and moisture content of coal, and improve the quality of coal, so as to make it more in line with the market demand.
一.Hydrocyclone common failure analysis
Although hydrocyclone for industrial production to bring a lot of convenience, but its long-term operation process, it is inevitable that will encounter a variety of failures, not only affect the normal operation of the equipment, but also may lead to a series of problems such as reduced productivity, product quality instability, and so on, to the enterprise to bring economic losses. Therefore, an in-depth understanding of the common failures of hydrocyclone and its causes, and master the corresponding solution is crucial to ensure the smooth progress of production.
1.Pressure fluctuations
In the operation of hydrocyclone, stable feed pressure is the key to normal operation of the equipment and achieve good classification results. Once the feed pressure fluctuations will have a serious negative impact on the performance of the equipment. When the feed pressure fluctuates, the capacity of the hydrocyclone will fluctuate. Too high a pressure will make the slurry flow rate inside the equipment too fast, resulting in a decline in classification accuracy, coarse particles and fine particles may not be effectively separated; too low a pressure will reduce the processing capacity, unable to meet the production requirements.
The reasons for the fluctuation of feed pressure are more complicated. Pump tank level drop is one of the common reasons, when the level is too low, the pump can not fully inhale the slurry, it will cause to feed the ore is not enough, and then cause pressure fluctuations. In some mines in mineral processing production, due to the instability of the ore supply system, resulting in frequent drops in the pump tank level, making the hydrocyclone feed pressure fluctuations drastic, seriously affecting the grading effect. In addition, air entering the pump can also lead to insufficient ore feeding, triggering pressure fluctuations. If the sealing performance of the pump is poor, or there are loopholes in the installation process, air may be mixed into the slurry, destroying the continuity of the slurry and affecting the normal work of the pump.
Debris entering the pump to cause clogging is also an important factor leading to pressure fluctuations. In actual production, the slurry may be mixed with a variety of impurities, such as ore fragments, wood chips, metal flakes and so on. Once these impurities into the pump, it will block the pump impeller, import and export pipelines and other parts, hindering the normal flow of slurry, so that the pump efficiency is reduced, resulting in pressure fluctuations to the mine.
For these problems, corresponding measures can be taken to solve the problem. When the pressure fluctuation caused by the decline in the pump tank level, you can increase the level to stabilise the pressure. Specific operations can be timely replenishment of slurry to the pump tank, or adjust the flow rate of the ore supply system to ensure that the pump tank level remains within a reasonable range. Closing one or two cyclones can also reduce the diversion of the slurry and improve the feeding pressure of a single cyclone; reducing the pump speed can likewise reduce the flow rate of the slurry and make the pump work more stable, thus alleviating pressure fluctuations.
If the pressure fluctuation is caused by pump clogging or wear, the pump needs to be overhauled. For clogged pumps, the pump should be promptly cleaned of debris, check the impeller, import and export piping and other parts of the blockage, and unclogging and cleaning. For worn pumps, repair or replace the relevant parts according to the degree of wear. If the impeller is lightly worn, it can be repaired and polished; if the wear is serious, it is necessary to replace the impeller with a new one. At the same time, the pump should be regularly maintained and serviced, such as adding lubricants, checking sealing performance, etc., in order to extend the service life of the pump and reduce the occurrence of pressure fluctuations.
2.Clogging failure
The clogging fault of hydrocyclone is one of the common problems affecting its normal operation, and timely and accurate judgement of the clogging situation is vital to ensure the smooth progress of production. In actual production, the overflow and underflow discharge can be observed to determine whether the hydrocyclone is clogged. When there are more coarse particles in the overflow, and the overflow and underflow flow is reduced, or even the underflow flow is cut off, and at the same time the sand is discharged in the form of a column, these are the obvious signs of hydrocyclone clogging. In addition, if the hydrocyclone long time violent vibration, also indicates that the equipment may be clogged.
The clogging part is mainly concentrated in the inlet and bottom flow mouth. When the overflow and underflow flow are reduced, it is likely that the hydrocyclone inlet is clogged. This is like a person’s throat being stuck by a foreign object, resulting in food and air not being able to pass through properly. At this point, the feed valve of the blocked hydrocyclone should be quickly closed, removed, and the blockage should be carefully removed. During the cleaning process, pay attention to safety to avoid being splashed by the slurry or scratched by the clogged material.
If the underflow flow is reduced or cut off, it is very likely that the underflow port is clogged. The bottom flow port is like the human body’s excretory organs, once blocked, it will lead to the waste can not be discharged normally. In this case, you can remove the flange connecting the bottom flow port and clean the debris in the bottom flow port. When cleaning, use the appropriate tools, such as hooks, shovels, etc., to ensure that the blockage is completely removed.
In order to effectively prevent the occurrence of clogging, facilities to stop the entry of coarse materials and debris can be installed in the feed pool of the hydrocyclone group, such as the installation of a debris removal screen. The debris screen can intercept the coarse particles and debris in the slurry and prevent them from entering the hydrocyclone. At the same time, the feed pool should be emptied in time when stopping the car to avoid the clogging phenomenon caused by precipitation and high concentration when driving again.
3.Bottom flow abnormalities
In the operation of the hydrocyclone, the state of the underflow is one of the important indicators to reflect whether the equipment is working properly. Under normal circumstances, the underflow discharge of the hydrocyclone should be ‘umbrella-shaped’, which indicates that the grading effect of the equipment is good, and the coarse particles in the slurry can be discharged smoothly from the underflow mouth. However, in actual operation, the underflow may have abnormal concentration and discharge.
When the concentration of the underflow is too large, the underflow will appear ‘columnar’ or intermittent ‘lumpy’ discharge. High underflow consistency can be caused by a number of factors, with high feed slurry consistency or a small underflow opening being common causes. When the concentration of feed slurry is too high, the content of solid particles in the slurry increases, making the concentration of the bottom stream increase accordingly; while the bottom stream opening is too small, it will limit the discharge speed of the bottom stream, resulting in the accumulation of bottom stream at the bottom stream opening and the concentration increases. For this situation, you can first make up the appropriate amount of water at the feed to dilute the concentration of the feed slurry and reduce the concentration of the underflow. If the concentration of the bottom stream is still large after replenishing water, it is necessary to replace the larger bottom stream port to increase the discharge rate of the bottom stream, so that the concentration of the bottom stream will return to normal.
On the contrary, if the bottom stream is discharged in an ‘umbrella shape’, but the concentration of the bottom stream is less than the required concentration, it may be caused by the low concentration of the feed material. At this point, it is necessary to increase the feed concentration to meet the production requirements. The feed concentration can be increased by adjusting the feed system, increasing the feed volume or increasing the solids content of the feed.
二.Hydrocyclone maintenance points in detail
1.Routine inspection and maintenance
Daily inspection and maintenance is to ensure the long-term stable operation of hydrocyclone foundation, can be timely found and solve potential problems, to extend the service life of the equipment. In the daily inspection, it is necessary to carry out a detailed inspection of all key parts of the equipment.
First of all, it is necessary to check whether the bolts of each ministry are complete and whether there is any looseness. Check whether the cyclone discharge port is blocked. When the discharge port is clogged, the cyclone will vibrate fiercely, and once the discharge port is found to be clogged, it should be shut down immediately to clean it up, so as to avoid further deterioration of the clogging situation. At the same time, it is necessary to check the wear and tear of the sand sinking port and overflow port. The sand sinking mouth and overflow mouth are the channels for the discharge of the ore slurry, which will be subject to the scouring and wear of the ore slurry in the course of long-term use. If the wear is serious, it will affect the grading effect and discharge state of the equipment.
Whether there is a leakage phenomenon in each connection of the equipment should not be ignored. Once the phenomenon of ore leakage is found, the leakage point should be found in time and corresponding measures should be taken to repair, such as replacing seals, tightening connection bolts and so on.
The flexibility and role of the pneumatic gate also need to be checked. The pneumatic gate is used to control the flow and flow direction of the slurry, if the pneumatic gate is not flexible or does not work, it will affect the normal operation of the hydrocyclone. When checking, the pneumatic gate should be operated to observe whether it can be opened and closed normally and whether the action is smooth.
In addition, it is also necessary to regularly clean the debris in the air compressor air filter, and it is generally recommended to clean it once a week. The role of the air filter is to filter dust and impurities in the air, preventing them from entering the inside of the air compressor and causing wear and tear on the air compressor. If the air filter is clogged, it will lead to insufficient air intake into the air compressor, affecting its efficiency and performance.
2.Wear and tear maintenance
Hydrocyclone in the operation process, due to the solid particles in the slurry in the high-speed flow of the internal components of the equipment to produce a strong scouring effect, wear and tear problems are inevitable.
As one of the main parts of the cylinder wall subjected to slurry scouring, its wear directly affects the service life of the equipment. In order to reduce the wear of the cylinder wall, wear-resistant materials can be used to make the cylinder wall, such as high hardness alloy materials, wear-resistant ceramics and so on. These wear-resistant materials have excellent wear resistance and impact resistance, and can effectively resist the scouring of the slurry.
The inlet is also easy to wear parts, because the slurry in the entry of the cyclone, will produce a large impact on the inlet. Wear on the inlet can be addressed by installing wear-resistant bushings at the inlet. Wear-resistant bushings can be replaced periodically at a relatively low cost and can effectively protect the inlet body. When the feed opening is found to be seriously worn, the wear-resistant bushing should be replaced in time to ensure smooth feeding and normal operation of the equipment.
Good maintenance of hydrocyclone is the key to guarantee its stable operation, prolong service life and improve production efficiency, which is of great significance in many aspects.
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