The quality of emulsion cranes (cranes used in emulsion environments) needs to be comprehensively evaluated from six core dimensions: structural design rationality, material corrosion resistance, manufacturing process accuracy, hydraulic system reliability, safety protection effectiveness, and operational stability. The specific analysis is as follows:

1、 Rationality of structural design: balance between load-bearing capacity and protection

structural optimization

The high-quality emulsion crane adopts finite element analysis (FEA) to optimize the main beam and leg structure, ensuring uniform stress distribution in the emulsion splash zone (such as the boom and the bottom of the frame), and avoiding strength reduction caused by local corrosion.

Example: A certain model of emulsion crane reduces the accumulation of emulsion at the bottom of structural components by increasing the inclination angle of the legs (from 5 ° to 8 °), resulting in a 40% decrease in bottom corrosion rate.

sealing design

The key parts (such as the hydraulic cylinder piston rod and pin shaft connection) adopt a double-layer sealing structure (O-ring+dust ring) to prevent emulsion from penetrating and causing lubrication failure.

Data: The failure rate of hydraulic systems caused by seal failure has decreased from 12%/year for single-layer seals to 3%/year for double-layer seals.

2、 Corrosion resistance of materials: full chain protection from substrate to coating

Substrate selection

High corrosion resistant steel (such as 316L stainless steel) is used for easily corroded components such as hydraulic cylinder piston rods and pin shafts, with a pitting corrosion equivalent (PREN) of ≥ 30, much higher than the 12-15 of ordinary carbon steel (Q235).

Comparison: In an environment with an emulsion pH of 7.5 and chloride ions of 150mg/L, the corrosion rate of 316L stainless steel is only 0.002mm/year, while Q235 steel reaches 0.15mm/year.

Coating system

The high-quality coating adopts a three-layer structure of "epoxy zinc rich primer (80 μ m)+epoxy mica iron intermediate paint (120 μ m)+polyurethane topcoat (60 μ m)", with a salt spray resistance time of ≥ 2000 hours and adhesion of ≥ 5MPa.

Case: After 5 years of use, the emulsion suspension coating of a certain enterprise still maintained a gloss retention rate of 85% for the topcoat, while the coating without a three-layer structure experienced extensive peeling after 3 years.

3、 Manufacturing process accuracy: details determine reliability

welding quality

The key welds (such as the connection between the main beam and the support legs) are welded using fully automatic welding technology, with a weld penetration depth of ≥ 80% and a porosity rate of ≤ 0.5%, which is much higher than the manual welding with a penetration depth of 60% and porosity rate of 3%.

Testing: Through ultrasonic testing (UT), the first pass rate of high-quality welds reaches 99%, while manual welds only reach 85%.

assembly accuracy

The assembly clearance of hydraulic cylinders, pulley systems and other components should be controlled within the range of 0.1-0.3mm to avoid emulsion infiltration due to excessive clearance.

Data: Hydraulic cylinders with excessive assembly clearance have a 60% reduction in seal life and a 3-fold increase in failure rate.

4、 Reliability of hydraulic system: dual guarantee of anti pollution and corrosion resistance

Hydraulic oil selection

Choose anti emulsification hydraulic oil (such as ISO VG46 anti-wear hydraulic oil), with an oil-water separation time of ≤ 15 minutes (ASTM D1401 standard), much lower than the 30 minutes of ordinary hydraulic oil.

Case: Due to the use of ordinary hydraulic oil, the lubrication performance of the emulsified oil in a certain emulsifying crane decreased, and the service life of the hydraulic pump was shortened from 5000 hours to 1500 hours.

Hydraulic pipeline design

The pipeline is made of 316L stainless steel material, with a bending radius of ≥ 5 times the pipe diameter, to avoid emulsion retention caused by pipeline deformation.

Comparison: The corrosion perforation time of stainless steel pipelines is ≥ 10 years, while that of ordinary carbon steel pipelines is only 3-5 years.

5、 Effectiveness of Safety Protection: From Passive Protection to Active Monitoring

Electrical protection

The electrical cabinet adopts an IP65 protection level, and the internal wiring is laid to avoid emulsion splashing areas, and a moisture-proof heater is installed (automatically started when the temperature is ≤ 5 ℃).

Data: The electrical failure rate of IP65 protection is only 1/5 of IP54.

safety device

Equipped with safety devices such as overload limiter (accuracy ± 3%) and lifting height limiter (action error ≤ 50mm), and certified by CE.

Case: A certain emulsion crane had its main beam deformed due to the failure of an overload limiter, and the repair cost reached 30% of the equipment value. However, high-quality safety devices can prevent such accidents.

6、 Operational stability: performance retention for long-term use

No load and load testing

High quality emulsion cranes need to pass tests such as no-load operation (≥ 5 minutes), step-by-step loading at rated pressure 25% -100% (each level ≥ 15 minutes), and continuous operation at full load (≥ 3 hours) to ensure no leakage, vibration, or abnormal noise.

Standard: When operating at full load, the oil temperature should be ≤ 85 ℃ and the volumetric efficiency should be ≥ 95%.

Overload test

Run at 1.25 times the rated pressure for 15 minutes, then run without load for 5 minutes, three consecutive times without any faults, to verify the structural strength and reliability of the hydraulic system.

Case: A certain emulsion crane failed the overload test and experienced a hydraulic cylinder explosion during use, resulting in the equipment being scrapped.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment