Unveiling the Heart of a Crane: How Does the Hydraulic System Drive a Thousand-ton Boom?

The core secret of why a crane can easily lift a thousand-ton load lies in its "heart" - the hydraulic system. This seemingly simple oil circuit system actually contains exquisite physical principles and engineering wisdom.

I. Three core Components of the hydraulic system

Hydraulic pump

The hydraulic pump is responsible for converting mechanical energy into hydraulic energy, just like the human heart pumps blood. Common gear pumps have a simple structure and low cost, while large cranes mostly use plunger pumps, whose working pressure can reach an astonishing 35 megapascals, equivalent to 350 atmospheres of pressure.

Control valve group

These precise valves are like traffic command centers, precisely controlling the flow direction and pressure of the oil. The directional control valve determines the extension and retraction of the cylinder, the pressure control valve prevents the system from overloading, and the flow control valve can precisely adjust the movement speed.

Hydraulic cylinder

Single-stage oil cylinders are suitable for short-stroke operations, while multi-stage telescopic oil cylinders can extend like telescopes, providing a larger working range for cranes. These cylinders can convert hydraulic energy into powerful mechanical force.

Ii. The Power Code of Hydraulic Oil

The reason why the hydraulic system is so powerful lies in the application of PASCAL's Law. This physical principle tells us that in a closed container, pressure can be transmitted uniformly. By applying a small force to the small piston, a huge output force can be generated on the large piston.

The choice of hydraulic oil is also of vital importance. High-quality hydraulic oil needs to have a high viscosity index and be able to maintain stable performance at extreme temperatures ranging from minus 30 degrees to 100 degrees. At the same time, it should also have anti-foaming properties to prevent cavitation damage caused by bubble formation.

Iii. Breakthroughs in Modern Hydraulic Technology

Modern cranes adopt electro-hydraulic proportional control technology, which has enhanced the control accuracy to an astonishing ±0.5%, far exceeding the ±5% level of traditional mechanical valves. The response speed has also been significantly improved, making the operation more precise and smooth.

More advanced systems are also equipped with energy recovery devices. When the boom is lowered, it can convert gravitational potential energy into electrical energy for storage, significantly improving energy utilization efficiency. This innovative design makes the crane both powerful and environmentally friendly.

Iv. Common Faults and Maintenance

The most common fault of the hydraulic system is the excessively high oil temperature. When the temperature exceeds 80 degrees, it will accelerate the aging of the oil, and the cooling system must be checked in time. Another common problem is slow operation, which is often caused by oil contamination. The filter element needs to be replaced regularly. It is recommended to carry out maintenance every 500 hours of operation.