How to improve the working efficiency of excavators in earth-moving work
Digging is one of the main tasks of an excavator. Today, I will share with you 5 tips on how to improve work efficiency during digging.
used Excavator loading
First, when digging, the arm cylinder is generally used as the main force, and the boom cylinder is used as the auxiliary force. The angle of the bucket teeth should be adjusted according to the travel trajectory of the arm. The bucket teeth must be "inserted" into the soil, not "slapped" into the soil. After inserting to a certain depth, the bucket is hooked and the arm is lifted. In this way, it is a perfect digging action.
Second, if you are digging along the edge of the soil and the soil is relatively hard, it is best to use only two or three bucket teeth to cut the soil first, and then dig it up together. This can effectively improve the overall work efficiency.
Third, when loading or other operations that require efficiency, each bucket of digging must be filled. After lifting the bucket, try to stop all other actions and only do the rotation action with all your strength. In this way, the rotation action speed will be the fastest.
Excavator loading a truck
Fourth, when digging and rotating, the bucket is not horizontal, but slightly open, so that the soil will not be thrown out from behind the bucket due to inertia, and the bucket will open faster when unloading the soil.
Fifth, when unloading soil, it is not necessary to pour out the soil entirely by opening the bucket. Instead, it is faster to use the bucket rod to instantly retract and then open it to throw the soil out.
For mechanical construction companies, the good or bad technical condition of construction machinery is a direct factor in the normal production of the company. Most of the current construction machinery adopts electromechanical and hydraulic integration, and the normal operation of the hydraulic system is a major sign of its good technical condition. Qualified hydraulic oil is the guarantee for the reliable operation of the hydraulic system. Correct maintenance is the basis for the reliable operation of the hydraulic system. To this end, the author makes a rough discussion on the maintenance of the hydraulic system of construction machinery based on work practice.
1 Choose suitable hydraulic oil
Hydraulic oil plays the role of transmitting pressure, lubrication, cooling and sealing in the hydraulic oil system. Improper selection of hydraulic oil is the main cause of early failure and reduced durability of the hydraulic system. Hydraulic oil should be selected according to the brand specified in the random "Instruction Manual". When substitute oil is required in special circumstances, its performance should be the same as that of the original brand. Hydraulic oils of different brands cannot be mixed to prevent chemical reactions and performance changes in the hydraulic oil. Dark brown, milky white, and smelly hydraulic oil is deteriorated oil and cannot be used.
2 Precautions for regular maintenance
At present, some engineering machinery hydraulic systems are equipped with intelligent devices, which have warning functions for certain hidden dangers of the hydraulic system, but their monitoring range and accuracy are limited. Therefore, the inspection and maintenance of the hydraulic system should combine the monitoring results of the intelligent device with regular inspection and maintenance.
2.1 250h inspection and maintenance
Check the attachments on the filter screen, such as excessive metal powder, which often indicates oil pump wear or cylinder pull. In this regard, it is necessary to diagnose and take corresponding measures before starting. If the filter screen is damaged or dirt accumulates, it should be replaced in time, and the hydraulic oil should be replaced at the same time if necessary.
2.2 500h inspection and maintenance
After the engineering machinery has been running for 500h, the filter element should be replaced regardless of its condition, because it is difficult to detect the slight damage of the filter element with the naked eye. If it is operated at high temperature for a long time, the filter element should be replaced in advance.
2.3 1000h inspection and maintenance
At this time, the filter should be cleaned, the hydraulic oil tank should be cleaned, the filter element and hydraulic oil should be replaced, and the oil change time for long-term high-temperature operation should be appropriately advanced. It is most economical to guide the oil change through oil quality detection and analysis, but it is important to pay attention to the extended use of hydraulic oil. It should be tested every 100h to timely detect and replace the deteriorated hydraulic oil.
2.4 7000h and 10000h inspection and maintenance
At this time, the hydraulic system of the construction machinery needs to be inspected by professionals and necessary adjustments and repairs should be made. According to practice, imported hydraulic pumps and hydraulic motors must be overhauled after working for 10,000h, otherwise the hydraulic pumps and hydraulic motors may be damaged due to disrepair, which is fatal to the hydraulic system.
3 Prevent solid impurities from mixing into the hydraulic system
Clean hydraulic oil is the life of the hydraulic system. There are many precision parts in the hydraulic system, and some are equipped with damping holes or gaps. If solid impurities invade, it will cause the precision parts to be strained, carded, and the oil channel to be blocked, endangering the safe operation of the hydraulic system. The general ways for solid matter to invade include: unclean hydraulic oil; unclean refueling tools; careless refueling, repair and maintenance; hydraulic component desquamation, etc. Solid impurities can be prevented from invading the system from the following aspects:
(1) Hydraulic oil must be filtered when refueling, and refueling tools should be reliably clean. Do not remove the filter at the refueling port of the hydraulic oil tank to increase the refueling speed. Refueling personnel should use clean gloves and work clothes.
(2) When disassembling the hydraulic oil tank refueling cap, filter cap, inspection hole, hydraulic oil pipe and other parts during maintenance, avoid dust when the hydraulic system oil channel is exposed, and the disassembled parts must be thoroughly cleaned before opening. For example, when disassembling the hydraulic oil tank refueling cap, first remove the dirt around the tank cap, loosen the tank cap and remove the debris remaining in the joint (do not rinse with water to prevent water from seeping into the tank), and open the tank cap only after confirming that it is clean. If you need to use wiping materials and hammers, you should choose wiping materials that do not remove fiber impurities and special hammers that hit rubber attached to the surface. Hydraulic components and hydraulic hoses should be carefully cleaned and blown dry with high-pressure air before assembly. Choose a genuine filter element with good packaging (if the packaging is damaged, the filter element may be unclean even if it is intact). Clean the filter at the same time as the oil change. Before installing the filter element, use a wiping material to carefully remove the dirt inside the filter housing.
(3) The hydraulic system cleaning oil must use the same brand of hydraulic oil as the system, the oil temperature must be between 45 and 80°C, and the impurities in the system must be removed as much as possible with a large flow rate. The hydraulic system must be cleaned more than three times, and the oil must be discharged from the system while it is hot after each cleaning. After cleaning, clean the filter again, replace the new filter element and add new oil.
4 Prevent air and water from invading the hydraulic system
4.1 Prevent air from invading the hydraulic system
At normal pressure and temperature, the hydraulic oil contains 6% to 8% air by volume. When the pressure is reduced, the air will be released from the oil, and the bubbles will burst, causing "cavitation" of the hydraulic components and generating noise. A large amount of air entering the oil will aggravate the "cavitation" phenomenon, increase the compressibility of the hydraulic oil, make the operation unstable, reduce the working efficiency, and cause the actuator to "creep" and other adverse consequences. In addition, air will also oxidize the hydraulic oil and accelerate its deterioration. To prevent air intrusion, the following points should be noted:
1) After maintenance and oil change, the air in the system should be removed according to the "Instruction Manual" that comes with the machine.
2) The suction pipe of the hydraulic oil pump must not be exposed to the oil surface, and the suction pipe must be well sealed.
3) The seal of the oil pump drive shaft should be good. When replacing the oil seal at this location, a "double-lip" genuine oil seal should be used. It cannot be replaced with a "single-lip" oil seal, because the "single-lip" oil seal can only seal oil in one direction and does not have the function of sealing air. After the overhaul of a Liugong ZL50 loader in our unit, the hydraulic oil pump had continuous "cavitation" noise, the oil level in the oil tank automatically increased, and other faults. After checking the repair process of the hydraulic oil pump, it was found that the oil seal of the hydraulic oil pump drive shaft was misused with a "single-lip" oil seal.
4.2 Prevent water from invading the hydraulic system
Excessive water in the hydraulic oil will cause the hydraulic components to rust, the oil to emulsify and deteriorate, the strength of the lubricating oil film to decrease, and accelerate mechanical wear. In addition to preventing water intrusion during maintenance, it is also necessary to tighten the lid of the oil storage barrel when not in use, and it is best to place it upside down; hydraulic oil with high water content must be filtered multiple times, and the dried filter paper must be replaced each time it is filtered. When there is no special instrument for detection, the hydraulic oil can be dripped onto the hot iron plate. It can only be refilled when there is no steam coming out and burning immediately.
5 Precautions during operation
5.1 Engineering machinery operation should be gentle and smooth
Engineering machinery operation should avoid roughness, otherwise it will inevitably produce impact loads, causing frequent engineering machinery failures and greatly shortening its service life. The impact load generated during operation will, on the one hand, cause early wear, fracture, and breakage of the engineering machinery structure, and on the other hand, cause impact pressure in the hydraulic system, which will damage the hydraulic components, premature failure of the oil seal and the high-pressure oil pipe joint and the compression joint of the hose, leaking or bursting the pipe, and frequent operation of the overflow valve will cause the oil temperature to rise. Our unit has newly purchased a UH171 front shovel excavator. During operation, the bucket door oil pipe will leak or burst every 4 to 6 days. The oil pipe is a pure imported product, and there is no quality problem after inspection. Through on-site observation, it was found that the bucket door was strongly hit against the limit block and door frame when it was opened and closed. To effectively avoid the impact load: the operating procedures must be strictly followed; the hydraulic valve should not be opened or closed too violently or too quickly; avoid causing the working device components to move to the extreme position to produce strong impact; hydraulic equipment without impact function cannot use the working device (such as the bucket of the excavator) to violently impact the working object to achieve the purpose of crushing. There is another issue worth noting: the operator must remain stable. Because the free clearance of each equipment control system is different, the clearance of the connection parts is different due to the different degree of wear, and the output of the engine and hydraulic system is also different. These factors give the equipment personality. Only when the operator of the equipment carefully explores and corrects his own operating actions to adapt to the personality of the equipment, can he develop good operating habits that conform to the personality of the equipment after long-term operation. The construction machinery industry adheres to the system of fixed people and fixed machines, which is also one of the factors.
5.2 Pay attention to cavitation and overflow noise
Always pay attention to the sound of the hydraulic pump and the overflow valve in the operation of construction machinery. If the hydraulic pump has "cavitation" noise, the cause should be found out and the fault should be eliminated before use. If an actuator moves slowly without load and is accompanied by the overflow sound of the overflow valve, it should be stopped immediately for inspection.
5.3 Strictly implement the handover system
When the handover driver parks the construction machinery, the safety and convenience of the inspection by the successor driver should be ensured. The inspection content includes whether the hydraulic system is leaking, whether the connection is loose, whether the piston rod and hydraulic hose are damaged, whether the low-pressure oil inlet pipe of the hydraulic pump is connected reliably, and whether the oil level of the hydraulic oil tank is correct. In addition, the vent holes of the normal pressure hydraulic oil tank should be checked and cleaned to keep them unobstructed to prevent the vent holes from being blocked and causing a certain vacuum in the hydraulic oil tank, which makes it difficult or damaged for the hydraulic oil pump to absorb oil.
5.4 Maintain a suitable hydraulic oil temperature
The operating temperature of the hydraulic system is generally controlled between 30~80℃. If the oil temperature of the hydraulic system is too high, it will cause: the viscosity of the hydraulic oil will decrease, which may cause leakage and reduce efficiency; the strength of the lubricating oil film will decrease, which will accelerate the wear of the machinery; carbides and sludge will be generated; oil oxidation will accelerate, and the oil quality will deteriorate; oil seals and high-pressure hoses will age prematurely, etc. In order to avoid excessive temperature; do not overload for a long time; pay attention to the radiator, and the heat sink should not be contaminated by oil to prevent dust from adhering to the heat dissipation effect; maintain a sufficient amount of oil to facilitate the circulation and heat dissipation of the hydraulic oil; do not operate all day in the hot summer, and avoid the high temperature at noon. When the hydraulic oil temperature is too low, its viscosity is high, the fluidity is poor, the resistance is large, and the working efficiency is low; when the oil temperature is below 20℃, sharp turns are prone to damage the hydraulic motor, valves, pipelines, etc. At this time, warm-up operation is required. After starting the engine, run it at idle speed for 3~5 minutes without load, then increase the engine speed with a medium-speed throttle, and manipulate the handle to make any action of the working device (such as the excavator bucket) to the extreme position, and keep it for 3~5 minutes to allow the hydraulic oil to heat up through overflow. If the oil temperature is lower, the warm-up operation time needs to be appropriately increased.
5.5 Control of hydraulic oil tank air pressure and oil volume
When working, pay attention to the hydraulic oil tank air pressure of the pressure type hydraulic oil tank at any time, and its pressure must be kept within the range specified in the "Instruction Manual". When the pressure is too low, the oil pump will be damaged due to insufficient oil suction; when the pressure is too high, the hydraulic system will leak oil, which may easily cause the low-pressure oil circuit to burst. For engineering machinery after maintenance and oil change, after exhausting the air in the system, check the oil level according to the "Instruction Manual" specified in the "Instruction Manual", park the engineering machinery on a flat place, and check the oil level again after the engine is turned off for 15 minutes, and replenish it if necessary.
5.6 Other precautions
During the operation of engineering machinery, prevent flying stones from hitting hydraulic cylinders, piston rods, hydraulic oil pipes and other components. If there are small scratches on the piston rod, use oilstone to grind off the edges around the small spots in time to prevent damage to the sealing device of the piston rod. It can continue to be used without oil leakage. For engineering machinery that has been shut down for more than 24 hours, oil should be added to the hydraulic pump before starting to prevent damage due to dry grinding of the hydraulic pump.
