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Photo | Bosch Rexroth AG

Mobile concrete pumps – Zoomlion soaring to record heights in China

November 2013

 

One of the world’s largest construction implements has been engineered in China. Using a hydraulic system, Zoomlion’s concrete pump conveys building material up to dizzying heights of over 100 meters.

 
 

Nowhere are cities currently growing faster than in China. In conurbations such as Shanghai and Beijing, skyscrapers seem to be springing up like mushrooms. To keep up with this growth, construction companies need building equipment to match. One such piece of equipment is the portable concrete pump from Chinese construction machinery manufacturer Zoomlion. It reaches up impressively into the sky, to a height of exactly 101.18 meters. That is the absolute pinnacle in this field – and even attracted interest from Guinness World Records. Apart from its sheer size, the Zoomlion pump is of course also convincing in its technology: A glance into the inner workings of the concrete pump reveals state-of-the-art hydraulics.

Flexible but strong

The design of a machine like the concrete pump always has to satisfy conflicting expectations. The placing boom must of course be robust right to the tip, but nevertheless flexible enough for versatile service. That naturally has an impact on the selection of components. “The limited load bearing capacity requires all the main components to be highly efficient with as low dead weight as possible,” as Binxing Wu, chief engineer at Zoomlion, explains. He and his team were thus delighted when the latest axial piston pump, model A4VG, was presented to them at a meeting with long-term supplier Bosch Rexroth.

A few PowerPoint slides were enough to convince the Zoomlion engineers that they had found their new feed pump. All the items in the specification were ticked off: high operating pressure, large displacement volume, and highly integrated functions tailored to the required application. From a safety point of view, too, the axial piston pump passed with flying colors, despite the stringent requirements.

In order to avoid accidents or damage, no critical vibrations can be permitted to arise in the placement boom, despite its enormous length. The axial piston pump, however, switches so rapidly and gently that no such vibrations can occur. Furthermore, the integrated pressure relief system prevents pressure peaks from developing in the system.

Challenges in integration

On paper, everything was as it should be. Now the ball was in the project engineers’ court, as they had to integrate the axial piston pump into the system as a whole. The greatest challenge in that regard was – as almost always in international projects – the different standards in the different countries. The engineers had to make a number of adjustments to joints and connections for the axial piston pump to run smoothly in Chinese machines. “In cases like this, of course, our regional company in the country concerned makes our work a lot easier,” as Christian Frick, project engineer at Bosch Rexroth in Germany, explains. “Working together with our Chinese colleagues and in a number of personal meetings with the customer we were enabled to grasp all of Zoomlion’s needs very rapidly.”

The project partners took the hurdles in delivery periods and logistics just as smoothly, although time was especially scarce in the project. Work started in the spring of 2012, and the machine was to be complete by October. Here, too, communication was everything. Sales and logistics in the two companies cooperated so efficiently that in the end the best possible process was adopted and the concrete pump arrived promptly for the presentation.

“The use of our axial piston pump in the concrete pump has a favorable effect on the Chinese market. It puts the products from Zoomlion and Rexroth on a new level,” is the assessment of Zhicai Zhang, Bosch Rexroth’s Trade Sector Manager for concrete machines in China. “On the basis of the demand and market feedback, this concrete pump, more than 100 meter tall, has excellent potential for the future,” as Binxing Wu of Zoomlion confirms. Both are convinced that even more world records will soon be broken in China with the aid of modern hydraulic technology.