一.Overview of horizontal deteriorating centrifuges
1.Working Principle Explanation
Horizontal deteriorating centrifuge is mainly composed of drum, screw, differential speed system and so on. The working principle is to use the density difference between solid and liquid phases, under the action of strong centrifugal force produced by the high-speed rotating drum, the solid particles with larger specific gravity settle to the inner wall of the drum to form the mud layer, while the liquid with small density overflows through the overflow holes at the big end of the drum. The differential speed between the spiral and the drum causes the scraping screw to push the mud out of the rotating body, increasing solid-liquid separation.
2.Areas of application
Horizontal deteriorating centrifuge plays an important role in many fields. In the field of wastewater treatment, it can effectively remove suspended solids and sludge in wastewater, reduce the concentration of wastewater discharge, and realia environmental protection treatment. In the field of chemical industry, it can be used to separate various chemical raw materials, intermediates, products, etc., and improve product quality and recovery rate. In the food field, it can be used to separate fats, proteins, fruit juices, etc., to improve the quality and taste of food. In addition, it is also widely used in the fields of pharmaceuticals and mining, such as extracting, concentrating and separating drug components to improve drug purity and production efficiency; it is also used in mineral processing, failings recovery, etc., to improve resource mutilation and recovery rate.
二.Maintenance of horizontal deteriorating centrifuges
1.Daily maintenance points
Daily maintenance is essential to ensure the normal operation of the horizontal deteriorating centrifuge. First of all, you should check whether the equipment is clean around every day, clean up the dust and debris in time, and keep the environment around the equipment tidy. At the same time, carefully check whether there is any abnormal vibration in the equipment, and if vibration is found, it is necessary to stop the machine immediately to check the cause, because vibration may lead to rapid damage to the bearings on the bearing block, damage to the hood device and other damage, as well as loose bolts and other problems. In addition, pay attention to listening to the bearings whether there is an abnormal voice, once the abnormal sound, may be the precursor of bearing wear, need to be checked and dealt with in a timely manner. Ensure that the temperature of the bearing housing does not exceed 80 ℃, infrared thermometer and other tools can be used to monitor the temperature, if the temperature is too high, it may be the lack of oil or the bearing began to be damaged, you need to investigate the cause in a timely manner. Check the torque readings to understand the operating status of the equipment. If the torque is abnormal, there may be problems such as spiral wear. Check whether the differential oil leakage and whether the bearing seat oil leakage, if found oil leakage phenomenon, should be dealt with in a timely manner, to prevent oil leakage affects the performance of the equipment and cause potential safety hazards. Finally, check whether the elastic joint is deformed to ensure that all parts of the equipment are firmly and reliably connected.
2.Common Problems and Solutions
Vibration Problems
Problems that can arise from vibration include rapid bearing damage in the housing, damage to hood mechanisms, etc., excessive fatigue of rotating parts, and loose bolts. When equipment vibrates abnormally, it is important to stop operation and follow up to find the cause. If the centrifuge vibrates suddenly, the equipment may not have been thoroughly flushed during the shutdown, sludge may have built up between the screw and the drum, or the filtrate regulator plate may have come loose, and the tungsten carbide tiles interested on the screw may have come loose. If the centrifuge vibrates gradually, it may be due to spiral wear, damage to the spiral thrust bearing and the bearing in the housing, clearance in the groove shaft, damage to the damping block, loosening of the tightening screws of the downstream feed pipe, uneven blockage of the filtrate return pipe, etc.
Solution: For sudden vibration, the equipment should be thoroughly flushed, the sludge between the screw and the drum should be cleaned, and the filtrate regulating plate and tungsten carbide tiles should be checked and tightened. For gradual vibration, check the wear of the screw, replace the damaged bearings and damping blocks, tighten the loose screws, and clean the clogged filtrate return pipe.
Noise problems
If the centrifuge generates abnormal noise during operation, there may be problems such as worn bearings in the bearing housing, loose screws in the main machine cover or dry sludge discharge box, damaged or worn damping blocks.
Solution: Check the bearings in the housing and replace them if they are badly worn. Check the installation position of the screw to ensure that it is firm and not loose. Check the damping block and replace it if it is damaged or worn.
Overheating problems
Overheating is categorical as bearing housing overheating and reducer overheating. Housing overheating can be caused by overfilling grease bearings or by running out of grease and the bearings starting to break down. Reducer overheating can be caused by prolonged high torque, considerable speed difference between the output ring and the input or eccentric shaft, incorrect amount of grease or lubricant, incorrect type of grease or lubricant, premature damage to the reducer, too much tension on the belt, and so on.
Solution: For overheating of the bearing housing, if there is too much grease, wait a few hours for the bearing housing to cool down to normal temperature, if there is a lack of grease or if the bearing is damaged then add grease or replace the bearing. For reducer overheating, check and adjust the torque, make sure the speed difference between the output ring and the input shaft or eccentric shaft is within reasonable range, check whether the amount and type of grease or lubricant is correct, if the reducer is damaged too early, you can hand disc the eccentric shaft to check whether it rotates freely, adjust the tension of the triangle belt.
Overload problem
Mainly abnormal motor overload, there may be lubricating bearing oil problems, bearings may begin to break down, drum speed accelerated, material discharge torque has increased, one of the bearings on the bearing housing is damaged, filtrate outlet clogged, dry sludge discharge box stuffed with dry sludge, solids seeping into the frame, solid particles discharged from the filtrate drying up in the narrow passages between drum flanges and filtrate boxes, sludge drying up between the inlet pipe and screw conveyor housing, sludge drying up on feed bearings, sludge drying up between feed bearings, sludge drying up on feed bearings, and sludge drying up on feed bearings. The sludge dries up between the feed pipe and the screw conveyor shell, and the two screws supporting the drum at the end of the feed bearing seat are not fully loosened.
Solution: Check if the oil lubricating the bearings is normal, if there is any problem, replace the grease. Check whether the bearing is damaged, if so, replace the bearing. Adjust the speed of the drum, clean the dry knots in the filtrate outlet, the dry mud discharge box, the frame, and between the feed pipe and the screw conveyor shell, and make sure the screws are fully loosened.
三.Horizontal deteriorating centrifuge selection guide
1.Anti-corrosion performance considerations
In the selection of horizontal deteriorating centrifuges, anti-corrosion performance is one of the important factors for consideration. Since the materials separated by the centrifuge may have a certain degree of cohesiveness, the materials in contact with the materials must be able to meet the requirements of corrosion resistance to ensure safe use. Structural components material type, sealing ring, gasket material, surface treatment measures and filter cloth material and so on should be determined in the selection. In the selection of the nature of the material will be informed of the manufacturer, so that the manufacturer can be separated according to the characteristics of the media proposed centrifuge material selection recommendations, and specified in the order to ensure that the centrifuge corrosion requirements.
2.Explosion-proof performance requirements
If the centrifuge material (or environment) contains organic solvents and other flammable and explosive substances, then the centrifuge should have explosion-proof performance. Explosion-proof performance depending on the process of explosion-proof requirements to determine. In fact, the centrifuge to achieve the true meaning of explosion-proof, in the mechanical, electronic control, accessories and other aspects of the configuration to take a variety of measures. Such as electronic control systems, should be configured with explosion-proof barrier, non-contact energy braking system, electrostatic grounding, explosion-proof automatic control, etc.; mechanical systems, the need to use explosion-proof motors, explosion-proof lighting, anti-collision measures, anti-static drive belt, etc.; explosion-proof accessories, there should be nitrogen protection, nitrogen on-line detection, on-site explosion-proof control buttons, etc.. Therefore, for occasions with explosion-proof requirements, the user should specify the separated medium, explosion-proof requirements and levels when ordering, configure the corresponding devices and take appropriate measures to meet the explosion-proof requirements.
3.Separation performance evaluation
Separation performance is a basic function of horizontal deteriorating centrifuges, which needs to be evaluated in terms of separation effect, washing effect, processing capacity, degree of automation and so on. At the beginning of the order, due to the differences in the nature of the material, including the viscosity of the material, particle size, density, solid-liquid ratio of the slurry and other factors, it is difficult to accurately determine the effect of the final separation, and the separation factor of the centrifuge is generally used to measure the separation effect of the centrifuge. Separation factor and drum speed and drum diameter, and the angular velocity of the drum into a square relationship, that is, where: for the separation factor, for the drum angular velocity (r / s), for the drum diameter (mm), for the acceleration of gravity. The washing here refers to the washing of the filter cake, for some materials, the filter cake also needs to be washed by the washing liquid, and some even need to be washed several times to meet the requirements, which needs to be configured with a washing pipe. The washing effect, washing time and washing tube aperture, arrangement position, structure form has a great influence. The processing capacity of the centrifuge and the physical and chemical properties of the material and separation requirements, generally the number of cycles an hour and a single run to estimate the weight of the cake.
4.Supporting equipment selection
When selecting horizontal deteriorating centrifuges, priority should be given to the selection of complete sets of equipment in order to achieve good operating results. At present, the centrifugal sludge deteriorating equipment of many companies at home and abroad has excellent overall integration performance, and its coagulant dosing device, coagulant pump, sludge pump, automatic control system and so on are supplied with the centrifuge supporting. With the support of the automatic control system, the operation of all the equipment in the sludge deteriorating system and process parameters can be continuously monitored, for example, the level of sludge collecting tank, the operation of sludge pump, sludge flow rate, the operation status of coagulant pump, coagulant flow rate, screw speed, screw torque, drum speed, speed difference, etc. can be observed in real time, and real-time adjustments can be made according to the needs. These equipment form an organic whole under the support of the automatic control system, and the equipment perform very well with each other. Therefore, in the selection of equipment should try to use a complete set of equipment, to avoid only the choice of centrifuge host and the other choice of coagulant preparation system, sludge feed screw pumps, dosing screw pumps and so on. Even if you choose other related equipment, you should consult the centrifuge supplier as much as possible, and the selected equipment should be able to work well with the centrifuge’s self-control system, so that the sludge deteriorating system can achieve good operating results.