How to maintain cranes in hot summer？

The high temperature in summer will have a great impact on the mechanical performance, electrical system and hydraulic system of the crane. Good maintenance can effectively avoid equipment failure, extend service life and ensure operation safety. The following are the maintenance points of cranes in high temperature summer:

1. Maintenance of mechanical structure and transmission system
Key maintenance of lubrication system
High temperature will accelerate the oxidation and deterioration of lubricating oil/grease. It is necessary to shorten the oil change cycle according to the requirements of the manual (for example, the original oil change of 6 months can be advanced to 4-5 months in summer), and use high temperature resistant lubricating oil (for example, gear oil should use a higher viscosity grade model to avoid poor lubrication caused by viscosity drop at high temperature).
Check whether each lubrication point (such as bearings, pins, gear meshing) is unobstructed, ensure that the lubricating oil fully covers the friction surface, and pay special attention to the track lubrication of the trolley and trolley running mechanism to prevent high temperature dry friction from causing increased wear of components.
For cranes stored in the open air, it is necessary to clean the dust and sand on the guide rails and chains to prevent impurities from mixing with lubricating oil to form "abrasives" and accelerate component wear.
Anti-deformation and corrosion of metal structures
High temperature exposure will cause the temperature of the crane's metal structure (such as the main beam and outriggers) to rise suddenly, and it is easy to produce "thermal expansion and contraction" stress after encountering rain, which may cause weld cracking in the long run. It is necessary to regularly check key welds (such as the connection between the main beam and the end beam), and timely repair and anti-rust treatment if cracks are found.
The air is humid in summer, and the metal surface is prone to rust. It is necessary to apply anti-rust paint or grease to the exposed metal parts (such as hooks, pulleys, bolts), especially pay attention to equipment in corrosive environments such as the seaside and chemical plant areas, and increase the frequency of anti-rust treatment.
2. Electrical system maintenance
Heat dissipation and insulation protection
High temperature will cause difficulty in heat dissipation of electrical equipment such as motors, controllers, and distribution boxes. It is necessary to regularly clean the dust and oil on the surface of the equipment to ensure that the heat dissipation holes are unobstructed (such as using compressed air to blow the motor fan cover and the heat dissipation grille of the distribution box).
Check whether the insulation layer of cables and wires is aged or cracked due to high temperature, and pay special attention to the bends of mobile cables (such as trolley power supply cables and boom cables). If the insulation layer is found to be damaged, it needs to be replaced immediately to avoid short circuit or leakage.
For cranes operating outdoors, a sunshade can be installed outside the electrical control cabinet, or non-essential power can be cut off when the machine is shut down to reduce the equipment's no-load heating.
Motor and control system inspection
The motor is prone to overload at high temperatures, and the motor housing temperature needs to be checked (normally it should not exceed 70-80℃, which can be detected by an infrared thermometer). If the temperature is too high, it may be poor heat dissipation or bearing wear. The bearing clearance needs to be disassembled and checked, and the worn bearings need to be replaced and high-temperature grease added.
Check the contacts of electrical components such as contactors and relays. High temperature can easily cause oxidation and adhesion of the contacts. The contacts need to be polished with fine sandpaper to ensure good contact; at the same time, clean the dust in the contactor to prevent arc discharge from causing faults.
3. Hydraulic system maintenance
Temperature control and cleaning of hydraulic oil
High temperature will reduce the viscosity of hydraulic oil and enhance its fluidity, but it will also accelerate the oxidation of oil, produce sludge and impurities, and cause wear of hydraulic pumps, cylinders, and valve groups. It is necessary to check the temperature of hydraulic oil regularly (the normal working temperature should be 30-60℃, and the machine needs to be shut down for cooling if it exceeds 70℃). If it is frequently overheated, it is necessary to check whether the radiator is blocked.
Clean up dust, catkins and other debris on the surface of the hydraulic oil radiator (such as finned radiator) to ensure heat dissipation efficiency; if necessary, install an auxiliary cooling fan, or wrap insulation cotton outside the hydraulic oil tank to reduce the impact of high environmental temperature on the oil.
Regularly replace the hydraulic oil filter element (it is recommended to replace it every 200 hours in summer), and check the color and transparency of the oil. If it is blackened, emulsified or impurities are precipitated, the hydraulic oil needs to be replaced immediately to avoid clogging the oil circuit or scratching the inner wall of the cylinder.
Seal and pipeline inspection
High temperature will accelerate the aging of rubber seals (such as O-rings and oil seals) of hydraulic pipelines, and oil leakage is prone to occur. It is necessary to focus on checking whether there is leakage at the cylinder piston rod, hydraulic pump inlet and outlet pipes, and joints. If the seals are hardened or cracked, replace them with high-temperature resistant seals (such as fluororubber, which can withstand temperatures above 200°C) in time.
Avoid long-term exposure of hydraulic pipes to direct sunlight. Wrap the heat-insulating sleeve to prevent the pipes from deforming or the joints from loosening due to high temperature.
4. Cooling system and tires (for tire cranes)
Engine cooling system maintenance (automobile cranes, tire cranes)
Check the coolant level, ensure that the water tank and auxiliary water tank are full of coolant (use regular antifreeze, do not add tap water directly to avoid high-temperature scaling and clogging of the water tank), and check whether the cooling water pipes are leaking and whether the water pipe joints are loose.
Clean the catkins, dust and other debris on the surface of the water tank to ensure smooth ventilation of the heat sink; check the tightness of the fan belt (the belt deflection should be 10-15mm) to avoid belt slippage at high temperatures, resulting in insufficient heat dissipation and causing engine overheating.
Start the engine regularly and observe whether the water temperature gauge is within the normal range (80-90℃). If it frequently exceeds 95℃, check whether the thermostat is malfunctioning and whether the water pump is working properly. Replace the faulty parts if necessary.
Tire maintenance (tired crane)
High-temperature road surface will increase the tire temperature and the tire pressure is easy to exceed the standard. The tire pressure needs to be checked before operation every day (refer to the standard in the manual. It can be appropriately reduced by 0.1-0.2bar in summer to avoid excessive tire pressure and tire blowout after exposure to the sun).
Avoid parking tires on high-temperature ground (such as asphalt road) for a long time. Wooden boards or rubber pads can be used for heat insulation; check whether there are foreign objects such as stones and glass in the tire pattern, and clean them in time to prevent the tire rubber from being softened at high temperature and pierced by sharp objects.
If the tire tread is found to have cracks, bulges or wear to the warning line, it needs to be replaced immediately to avoid safety accidents caused by the decrease in tire strength at high temperature.
V. Maintenance of other key components
Braking system performance guarantee
High temperature will cause difficulty in heat dissipation when the brake pad (shoe) rubs against the brake drum (disc), and "thermal decay" (decreased braking effect) is prone to occur. It is necessary to check the brake clearance regularly (if the drum brake clearance is too large, adjust it in time), clean the oil on the brake pad (avoid high temperature slipping), and ensure sensitive braking.
The hydraulic brake system needs to check the brake fluid level and quality. The brake fluid is easy to vaporize and produce air blockage at high temperature. If the brake fluid is turbid or has bubbles, it needs to be completely replaced and exhausted.
Electrical components and control system
The filter element of the cab air conditioning system needs to be cleaned regularly to ensure normal heat dissipation and ventilation to avoid affecting the operator's status due to excessively high driving room temperature; at the same time, check whether the air conditioning refrigerant is sufficient to prevent the air conditioning from failing at high temperature.
Check the sensitivity of limit switches and sensors (such as height limiters and weight limiters). High temperature may cause electronic components to malfunction, and special instruments need to be calibrated to ensure normal safety protection functions.
VI. Daily operation and storage precautions
Avoid long-term operation during high temperature periods: try to arrange operations in the cool time in the morning and evening. When the temperature is high at noon (such as above 35℃), you can stop the machine for a rest and let the equipment cool down naturally.
Open-air storage protection: Cranes that are not used for a long time need to be parked under a sunshade or covered with a rainproof cloth to avoid direct sunlight and heavy rain; the negative pole of the battery needs to be disconnected to prevent high-temperature self-discharge.
Post-operation inspection: After the end of each day's operation, clean the oil and dust on the surface of the equipment, check whether there are abnormal heating and leakage signs on each component, and report problems in time to avoid small faults accumulating into big problems.
The core of crane maintenance in hot summer is "anti-high temperature, anti-aging, and anti-overload". By targeted maintenance of the weak links of each system, the equipment failure rate can be effectively reduced to ensure safe and efficient hoisting operations.