sewage treatment plants have a large number of processing facilities (or structures) and auxiliary production facilities. production process equipment such as grille waste traps, pumps, mixers, blowers, injection equipment, sludge thickener dewatering machines, mixing and mixing equipment, air diffusers, electric valves, etc. the failure of these process equipment will affect the operation of the sewage plant or cause the entire plant to stop.
1. operation and maintenance of grille decontamination machine
the grille should be a ready-to-use, not only emphasizes the maintenance of commonly used grid decontamination machines, but also requires regular maintenance of spare equipment, and many processing plants have seen cases where operating equipment and spare equipment are damaged together.
1 when the equipment is installed, care should be taken to adjust the gap between the fixed part and the moving part (such as the guide rail and the slider) to ensure that the decontamination unit moves up and down smoothly. adjust the position of each trip switch and the impact block, determine the time interval of the time relay, etc., so that the equipment completes the complete cycle action according to the design stipulated procedure.
2 after adjusting to normal, no-load test run for several hours, no trouble before entering the water into operation.
3 the refueling parts such as motor, reducer and bearing should be replaced with lubricating oil and grease as required. if regular ropes are used, grease should be applied regularly. this operation can prolong the service life of the equipment, and it can also prevent equipment damage due to wear.
4 regularly check the running status of the motor, reducer, etc., replace the worn parts in time, and replace them when the wire rope breaks stock more than the allowable range. at the same time, major and medium repair cycles should be determined and maintenance should be done on time.
5 regularly check whether the toggle bracket assembly is flexible, eliminate foreign objects in the clip, and check if the screws of each component are loose. the equipment of the grid decontamination machine is also greatly shaken, and the phenomenon of loose screws cannot be avoided.
2. daily management and maintenance of gates and valves
the maintenance of the gates and valves is of great significance. under normal circumstances, routine maintenance will not pay special attention, but once it is damaged, the losses caused are also great.
1 use and maintenance of gates and valves
a. lubrication parts of gates and valves are mainly made of screws, gears of deceleration mechanisms, and worm gears. these parts should be greased once every three months, or added according to specific conditions to ensure flexible rotation and prevent rust. some of the gate or valve screws are exposed and the exposed screws should be cleaned and greased with new grease at least once a year. some internal spiral gates have long-term screw contact with the sewage, and the attached dirt should be cleaned and greased with water-resistant paint. this operation is cumbersome, but it is very good for the operation of the device.
b. when using an electric brake or valve, pay attention to whether the hand wheel is disengaged and whether the lever is in an electric position. if you do not pay attention to the disengagement, once the protective device fails when the motor is started, the handle may rotate at high speed to injure the operator. this operation focuses on the operator's safety. in the event of an accident, not only will the operation be affected, it will also cause incalculable damage to the operator.
c. when manually opening or closing the gate or valve, it should be noted that the general force should not exceed 15kg. if you feel strenuous, it means that the valve stem has rust, stuck, or bent brake rods. if you increase the arm force, you may damage the valve. the rod should be rotated after troubleshooting; when the gate is closed, the gate handle should be reversed one or two turns, which is conducive to the gate restart.
d. the torque limit mechanism of the electric brake and the valve not only acts as an over-torque protector, but also acts as a backup parking protection when the stroke control mechanism fails during operation. its operating torque is adjustable and should be adjusted at any time within the torque range specified in the instructions. a few gate valves rely on torque limiting mechanisms to control the pressure of the gate or valve plate, such as some flap valves, conical mud valves, etc. if the adjustment torque is too small, it will not close tightly; otherwise it will damage the connection. rod, should pay special attention to the adjustment of the torque.
e. the opening and closing indicator of the valve and valve should be adjusted to the correct position. when adjusting, first close the valve or valve, and then turn the pointer to zero and then gradually open; when the gate or valve is fully open, the pointer should just point to the full open position. the correct instructions are helpful for the operator to grasp the situation and also help to find faults. for example, when the pointer is not in the fully open position and the motor is stopped, it should be judged that the valve may be stuck.
f. long-term closed sewage valves, sometimes forming a dead zone near the valve, where there will be sediment deposits, which will create resistance to the opening and closing of butterfly valves. if you find that the resistance increases when you open the valve, do not hard open, you should do repeated opening and closing action to promote the water to wash away the sediment, and then open the valve after the resistance decreases. at the same time, if there are frequent sand accumulations near the valve, the valve should be opened several minutes at a time to facilitate the removal of accumulated sand. similarly, for valves and valves that do not open and close for a long time, they should be run once or twice regularly to prevent rusting or silt dead.
2 common faults and solutions of gates and valves
a, valve closures damage and solutions to the reasons for damage due to improper closure material selection; the closed-circuit valve is often used as a regulating valve, high-speed flow of the medium to quickly wear the sealing surface. the solution is to identify the cause of the damage and switch to a suitable material or the closed circuit valve is not used as a regulating valve.
b. when the sealing ring does not tightly fit the sealing member and the closing member (the valve body and the valve seat), the sealing ring should be repaired. the ribbing of the valve seat and valve body is poor, so the valve seat is inclined and should be replaced when it cannot be repaired. when the valve seat is tightened, the force is not properly applied and the sealing member is damaged. during the operation, force should be applied to avoid damaging the valve. the valve does not comply with the installation procedures before installation. if the dirt and dust in the body cavity of the valve body are not well cleaned, welding slag, rust, dust, or other mechanical impurities remain on the surface, causing scratches, dents, and other defects on the sealing surface to cause valve failure. . strictly follow the installation procedures to ensure the installation quality.
c. leaking fillers in the filling room the entire packing is filled in the room. the packing should be filled in the correct way.
3, centrifugal blower operation and maintenance
1 when the blower is running, check the blower fan regularly. exhaust pressure and temperature, cooling water or oil level, pressure and temperature, air filter pressure difference. do a daily record reading, and analyze and contrast.
2 regularly inspect the air filter to keep it working properly.
3 pay attention to the influence of intake air temperature on blower (centrifugal) operating conditions, such as exhaust volume flow, operating load and power, possibility of surge, etc., and timely adjust the throttle device of the inlet guide vane or butterfly valve to overcome the intake air the influence of temperature changes on the volumetric flow rate and operating load makes the blower safe and stable.
4 regularly pay attention to and regularly listen to the sound of the unit's operation and the vibration of the bearing. if abnormal sound or vibration is found to be aggravated, take immediate measures. if necessary, stop and check, find out the cause, and troubleshoot.
5 the centrifugal blower unit must not be operated in the surge area.
6 according to the instructions, do a good job of inspection and maintenance of the motor or gear box.
7 when one of the following conditions occurs in the operation of the blower, stop immediately and check:
a. sudden vibration of the unit or friction sound in the casing;
b. emission of smoke from any bearing;
c. suddenly the bearing temperature rises above the permissible value, and various measures cannot be taken to reduce it.
d. 200h should be changed after the first drive. if the oil being replaced has not deteriorated, it can be reused after filtration by the filter. after 500 hours of driving for the first time, the oil sample was analyzed. after the oil sample analysis was performed once a month, it was found that the oil should be replaced immediately. the oil number must comply with the regulations and other brands of oil are strictly prohibited.
e. check the pumping position in the fuel tank. it must not be lower than the minimum oil level line to see if the oil pressure maintains the normal value. always check the oil temperature at the bearing outlet, should not exceed 60 °c, and adjust the amount of cooling water in the oil cooler according to the situation, so that the oil temperature before the water inlet bearing is maintained at 30 ~ 40 °c.
f. clean the oil filter regularly. always check the air filter for resistance changes. clean and maintain it regularly to keep it working. g. the unit is prohibited to operate in the surge area. centrifugal blowers are generally placed indoors. once a major fault occurs, it will not only cause operational problems, but it may also threaten the normal operation of other blowers. it is the focus of daily maintenance.
h. check and maintain the motor according to the requirements of the motor specification. motor troubleshooting:
4, pump switch
pump switching is divided into two cases, namely normal switching and emergency switching. normal switching for standby pump, in order to avoid long-term deactivation of the backup pump, shaft bending, deformation and other phenomena occur, and in order to perform normal maintenance and overhaul of the running pump, the pumps need to be switched periodically.
the principle of normal switching is: first stop and then stop. the steps are as follows:
1 press start to start the backup pump. after the backup pump is operating normally, keep the pressure flow of the system basically inconvenient (observe the pressure gauge and flow meter), slowly open the outlet valve of the backup pump, and close the outlet valve of the small pump until it is completely closed. . according to the normal stop operation, it is necessary to stop the pump and do a good job of maintenance to make it in a good standby state.
2 emergency switching when the pump runs, emergency switching or emergency stop should be taken if one of the following situations occurs: the motor current is too high, or one phase is burned out or the motor is on fire. the temperature of the bearing suddenly rises, smoke is emitted, and the shaft is in danger. when the shaft and shaft have a broken fracture sound. when the pump has a severe cracking sound. when a personal safety accident occurs.
when the process requires emergency switching or emergency stop, the principle of emergency switching is to stop and open first. the steps are as follows: immediately press the “stop” button to stop the operation of the accident pump. the spare pump is activated immediately as normal operation. close the pump outlet valve of the accident machine. if any maintenance is required, please ask the electrician to pull off the power and hang up the signboard. contact the serviceman to repair the decommissioned pump so that it is in perfect standby condition.
5. correct use of dosing equipment
the good operation of the dosing device in the operation of the sewage treatment plant directly affects the quality of the effluent, and it is mostly manual operation, which requires the operator to pay attention to it. in order to ensure the effectiveness of the treatment, the following points should be taken care of regardless of the type of coagulant or device used.
1 to ensure that the equipment is in good condition and that all the pharmaceuticals are adequate;
2 quantitative calibration of the metering device of the device for the injection of drugs to ensure that the dose of the drug complies with the technological requirements;
3 fully ensure that the pharmaceutical meets the quality requirements of the process requirements;
4 regularly check the quality of the original sewage to ensure that the dosage is adapted to the changes in water quality and the requirements for water discharge;
5confirm the concentration of the drug reservoir and the drug pool when handing over the shift;
6 regularly check the pipeline for the injection to prevent the pipeline from being blocked or broken to ensure the normal operation of the pumping system;
7 when the flow-breaking phenomenon occurs, check and repair as soon as possible.
6, sludge dewatering machine operation and maintenance management
sludge treatment systems have always been a source of headaches for sewage treatment plants. the complete operation of the equipment does not guarantee that the dewatering can achieve the best results. once damaged, it is a threat to the sewage treatment process.
1 routine maintenance management
a. observe and check the dewatering effect of the dehydrator regularly. if the solid content of the mud cake is found to be decreased, the separation liquid is turbid, and the solid recovery rate is decreased, the situation shall be analyzed in a timely manner and measures shall be taken to solve the problem.
b. routine flushing time should be ensured for the dewatering machine so that when the dewatering machine stops, the inside of the machine and the whole body are rinsed thoroughly to ensure cleanliness and reduce odor. it is very difficult to clean the mud afterwards. every day to ensure more than 6h rinse time, flushing water pressure is generally not less than 0.6mpa. in addition, the inside of the airframe should be cleaned periodically to ensure cleanliness and reduce odor.
c. pay close attention to observing the operating conditions of the sludge dewatering device. take corrective measures against abnormal phenomena to ensure normal operation. such as to prevent the filter belt from slipping, filter plugging, and filter belt deviation. prevent the coarse sand and scum winding on the spiral in the centrifugal dehydrator. d. since the sludge separation effect of the sludge dewatering machine is affected by the temperature of the sludge, it is necessary to intensify the insulation or increase the dosage of sludge in the winter.
e. according to the requirements of the dehydrator manual, do observation and maintenance of the observation items of the regular observation items. such as water pressure gauges, mud pressure gauges, oil pressure gauges and tension gauges and other operational control instruments.
f. always check the wear of the dewatering machine wear parts and replace them if necessary. for example, filter cloth, roller.
g. find out in time whether the coarse sand in the dehydrator enters the mud to affect the filter belt or the drum or the screw conveyor. if the damage is serious, it shall be immediately shut down and replaced.
2 analysis and elimination of abnormal problems
a. the reason for the decrease in the solid content of the filter cake and its solution are as follows. the effect of tempering is not good. generally due to insufficient dosage. when the incoming mud changes and dehydration performance decreases, it should be tested again to determine the appropriate dosage. sometimes it is due to improper drug concentration, high concentration of the drug, the flocculant is not easy to fully dissolve, although the amount of drug is enough, but the effect of conditioning is not good. it is also sometimes due to an unreasonable position of the dosing point that causes the flocculation time to be too long or too short. the above conditions should be tested and adjusted. the speed is too high. if the belt speed is too large and the mud cake is thin, resulting in a decrease in solid content, the belt speed shall be reduced in time. generally, the thickness of the mud cake is 5-10 mm. filter belt tension is too small. at this time, sufficient pressing force and shearing force cannot be ensured and the solid content is reduced. increase the tension appropriately. filter plugged. after the filter belt is clogged, water cannot be filtered out and the solid content is reduced. the operation should be stopped and the filter belt should be washed.
b. reasons for the reduction of solids recovery rate and control measures are as follows: the belt speed is too high, which leads to running materials in the extrusion area, and the belt speed should be reduced appropriately. too much tension leads to running in the squeezing area and makes part of the sludge pressure filter belt, with the loss of filtrate, should reduce the tension.
c. reasons for the sliding of the filter belt and the control countermeasures are as follows: into the mud overload, the load should be reduced. the filter belt tension is too small and the tension should be increased. the roller cylinder is bad and should be repaired or replaced in time.
d. the reasons for the frequent running of the filter belt and its control countermeasures are as follows: inhomogeneous mud feeding, uneven spreading on the filter belt, should be adjusted into the mud or replace the flat mud device. local damage or excessive wear of the barrel should be checked and replaced. the relative position between the barrels is not balanced and adjustments should be checked. the corrective device is not sensitive and should be checked for repair.
e. the cause of the plugging of the filter belt is severe and the control countermeasures are as follows: each flushing is not complete, the flushing time or the flushing water pressure should be increased. the strain on the filter belt is too high and the tension should be reduced appropriately. overdosed. pam overdosed, viscosity increased, often blocked filter cloth, in addition, not fully dissolved pam, it is easy to plug the filter. the amount of sand in the mud is too large, and it is easy to plug the filter cloth. the operation control of the sewage pretreatment system should be strengthened.
7, sludge dewatering supporting screw pump operation and maintenance management
1 prior to the initial start of the screw pump, all structures and pipelines should be cleaned to prevent debris from entering the pump body. a lot of hard debris will reduce the life of the stator and rotor.
2 the inlet and outlet valves should be opened before start-up. when starting, they should be filled with medium, no idling is allowed, and the conveyed medium has cooling and lubrication effects on the pump body.
3 before the first operation and after the overhaul, the accuracy of the concentricity should be checked to ensure stable operation.
4 in the course of operation, loosening of the base locust will cause the body's vibration, movement, pipeline rupture and so on. in particular, bolts at joints of universal joints and flexible shafts often check bolts for their firmness.
5 during normal operation, the stuffing box will be dripping water, and the water will play a role of lubrication. normally it should be 50 to 100 drops per minute. when it is over, it should be tightly bolted or replaced. the lubrication parts of the screw pump mainly include gearboxes, rolling shafts and couplings inside the bearings. the lubricant used in different parts is not the same, and it is lubricated according to the instructions in the operation.
6 patrols the running screw pump, 2h during the day. 4h in the evening. wells should pay attention to the following matters.
a. are the anchor bolts, flanges, and couplings loose?
b. is the gearbox oil level normal, whether it is leaking oil, warming, and whether the bearing heats up.
c. pay attention to the vacuum gauge on the suction pipe and the pressure gauge on the mud pipe. you can find out if the pump is idling and if the pipe is blocked. d. whether there is abnormal sound when listening to the operation.
7 carefully fill in the operation records, the main records of the contents of the working time and cumulative time, media status, bearing temperature, plus oil records, filler dripping water, and large and medium repair records.
8 the stator and rotor should be replaced regularly. the replacement method and cycle should be referred to the relevant requirements of the operating instructions.
9 screw pump common faults
a, can not start because of the following reasons. the new pump or the new stator has too much friction and liquid lubricant can be added. unsuitable voltage, control circuit failure, phase loss operation. the body content of the pump is large and there is blockage. when the machine stops, the media precipitates and agglomerates. the outlet was blocked and the inlet valve was open. winter freezes. universal joints, etc. were blocked by a large number of windings and could not be turned.
b. the reasons for the lack of mud are as follows. imports and exports blocked and imported valves did not open. universal joints or flexible connections are disconnected. the stator is badly damaged. turn against.
c. the reason for the low traffic is as follows. stator wear, internal leakage. speed is too low. inhalation pipe leak. the operating temperature is too low, so that the stator shrinks and the seal is not good. shaft seal leakage.
d. the reason for excessive noise and vibration is as follows. loose parts of bolts. damaged bearings (with bearing or gearbox heating). severe wear of stator or rotor (small amount of mud at this time). there is no medium in the pump and it is running. stator rubber is aged and carbonized. the motor deceleration 不同 is not concentric with the pump shaft or the coupling is damaged. couplings wear loose. transmission gear wear pitted.
e. the cause of the stuffing box heating is as follows. the packing is too tight. poor filler quality or improper use.
f. the reason why the stuffing box leaks too much water is as follows. improper use of fillers. the packing is not compacted or fails. shaft wear too much.
8. operation and maintenance of submersible sewage pump
whether it is a sewage treatment plant or a sewage treatment plant, the pumps must be the most used. the transmission of sewage and sludge is done by pumps. submersible sewage pumps can be said to be the heart of a sewage treatment plant (station). some areas can be free-flowing, but there will also be spare pumps, which are easily overlooked.
1 before starting the pump, check whether the impeller rotates flexibly and whether there is oil in the oil chamber. the direction of rotation should be correct after power-on.
2 check that the cable is particularly damaged or broken, and that the inlet seal of the junction box cable is in good condition. if any leakage or leakage is found, handle it in a timely manner.
3 do not use the pump cable as a hanging wire to avoid danger.
4 regularly check the insulation resistance between the motor phases and relative ground, which shall not be lower than the allowable value. otherwise, it shall be disassembled for gun repair, and at the same time check whether the electric pump grounding is solid and reliable.
5 put the person in clean water for several minutes after the pump is stopped to prevent deposits in the pump and ensure the cleanliness of the pump.
6 the pump should be removed from the water. do not immerse it in water for a long time to reduce the chance of motor stator windings getting wet. when the temperature is very low, it is necessary to prevent the pump housing from freezing.
7 the seal between the impeller and the pump body should not be worn and the clearance must not exceed the allowable value, otherwise the seal ring should be replaced.
8 after running for six months, check the sealing condition of the oil chamber of the apricot pump. if the oil in the oil chamber is emulsified or if water is precipitated, the 10-30 oil and mechanical seals should be promptly replaced.
9 do not disassemble the parts of the electric pump. do not bang it when it needs to be disassembled. hit it hard to avoid damaging the seal. under normal conditions, one year after the workpiece should undergo a major repair, replace worn wear parts and check the condition of the fasteners.
9, daily management and maintenance of metering pumps
the metering pump is an important basis for the operator to observe whether or not the equipment is operating properly. in particular, those who have just learned to debug and operate need more attention.
1 daily management of metering pumps
a. the oil level in the tank should be maintained and supplemented regularly.
b. the amount of leakage at the packing seal is no more than 8 to 15 drops per minute. if the leakage exceeds the amount, it should be dealt with promptly.
c. observe the temperature of each major part. the motor temperature does not exceed 70°c. the temperature of the lubrication oil in the transmission case does not exceed 65°c. the stuffing box temperature does not exceed 70°c. if the pump is decommissioned for a long time, the medium in the pump cylinder should be used. drain cleanly and clean the surface. apply exposed oil on the exposed surface.
2 see table 6-5 for the common faults and disposal methods of the pump.
10. pipeline operation management and maintenance
the common process pipelines in sewage treatment plants include sewage pipes, sludge pipes, liquid chemical pipes, compressed air pipes, water supply pipes, and biogas pipes. generally it can be divided into liquid transport pipelines and gas transport pipelines according to the difference of its transport medium. liquid transport pipelines can be further divided into pressurized liquid transport pipelines and pressureless liquid transport pipelines, while gas transport pipelines are mostly low pressure pipelines, and the main ones are air pipelines.
(1) maintenance of pressurized liquid conveying pipelines pipes are often used in sewage (pressure) piping, sludge piping, water supply piping, etc. the abnormal problems that may occur during operation and solutions are as follows.
1 pipeline leakage generally, leakage of water may occur due to loose joints or loosening of pipes, or corrosion of pipes. corrosion of pipes may occur in concrete, reinforced concrete, or buried soil. pipes in pipelines or supporting pipelines, when the support strength is not enough or damage, the joints of the pipeline is easy to loosen. in case of leakage or leakage of the pipeline caused by the above phenomena, in addition to the timely replacement of pipelines and good pipeline leakage, the maintenance work such as support and anti-corrosion should be strengthened.
2 when there are noisy pipelines in pipelines for non-buried installations, abnormal noise can be heard. the main reasons are:
a. the flow velocity in the pipeline is too large;
b. the connection between the pump and the pipeline or the foundation construction is incorrect;
c. deformation of the internal section of the pipeline (such as bending pipes, pressure relief devices) or reduction (partial obstruction);
d, valve seals, etc. can not see loose and shake. the above abnormal problems can be taken to solve corresponding measures, such as replacing pipes or valve fittings, changing the inner section of the pipeline or clearing the pipeline, and doing a good job of preventing and shocking the water pump.
(3) cracks or breakages (bubbles) in pipelines. for example, due to the shallow burial of pipelines, the number of trucks passing through will become crushed; the gate valve will close too tight and cause damage due to water hammer; the pipeline will be damaged by stray soil erosion and water pressure; high and damaged. cracks or damage should be replaced in time.
4 when pipelines are frozen and cracked and pipes are laid above the freezing depth of soil, sewage (muddy) pipelines are susceptible to freezing and cracking. the solution to this problem is to re-lay pipelines and re-insulate the sewers (for example, replace soil around the pipeline with slag, wood chips, or coke, and pad the 20-30 cm sand layer in the above material), or appropriately increase the temperature of the conveying medium. .
(2) non-pressure liquid transport non-pressure transmission pipelines for sewage treatment plants (stations), mostly sewage pipelines, sludge pipelines, overflow pipelines, etc., are generally cast iron pipelines, stern pipelines (or earthenware pipelines), and are continuous with sockets. steel pipe welded or flanged. the common failure of pressureless piping system is water leakage or pipeline blockage. the routine maintenance work is to eliminate the leakage point and clear the blocked pipeline.
1 the leaking of pipes caused by water leakage is mostly due to lax pipe connections, or pipe fittings with trachoma and cracks. leakage caused by lax interface, should deal with interface re-treatment, if it still does not work, you must remove the interface with a hand hammer and curved chisel, reconnect; if the pipe or pipe fittings have blisters, cracks or breakage caused by leakage, it should be promptly damaged pipe fittings or pipe sections are replaced, and the casing joints are connected with the original pipelines. if there are other reasons, such as vibration, the joints are not strict, corresponding measures should be taken to prevent the pipelines from being damaged again.
(2) causes of pipe blockage caused by pipe plugging in addition to the user not paying attention to dropping hard blocks, rags, cotton yarns, etc. into the pipe, the main reason is that the pipe slope is too small or the slope of the pipe causes the flow rate in the pipe to be too slow, and impurities in the water deposit in the pipe. block the pipe. if there is a problem with the laying slope of the pipeline, the slope of the pipeline should be adjusted according to the relevant requirements. when blocked, it can be dredged manually or mechanically. maintenance personnel should always check whether the pipeline is leaking or blocked. the inspection well should be closed to prevent debris from falling.
(3) common faults and remedies for compressed air piping there are two common types of faults in compressed air piping.
(1) the cause of gas leakage from piping system leakage is often due to the poor quality of the materials and accessories or poor installation quality. the sinking of the brackets in the pipeline causes serious deformation and cracking of the pipeline. the water in the pipeline is severely frozen and the pipes or fittings are ruptured.
2 pipe plugging pipe plugging is characterized by insufficient supply pressure and air volume, and a large pressure drop. the cause is generally caused by impurities or fillers coming off the pipe, the valve being damaged, and the water in the pipe freezing. the method to eliminate this type of failure is to remove the impurities in the pipe, repair or replace the damaged valve, and remove the accumulated water in the pipe in time.
article source: new environmental protection classroom
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