By order of a Belgian machine factory, Hydrauvision Systems has developed the drive and the controls for a heavy hydraulic press. The client was a leading manufacturer of construction elements such as roofing and façade panels. The company is the Belgian market leader in solutions for roofs, façades and walls.
The hydraulic press is used to remove water from fibre cement panels. By compressing a stack of panels under high pressure, the water is pressed out and a dry panel remains. Compression is followed by a process that will give the panels the desired final strength.
A stack of 50 fibre cement panels, measuring 2.6m x 1.8m, has a maximum thickness of 1.8m. The panels are separated by thin stainless steel plates. To be able to remove a maximum amount of water from the panels, as quickly as possible, a pressure force of no less than 13,000t is required.
The hydraulic press comprises a yoke containing six cylinders. These pressure cylinders have a maximum operating pressure of 350 bar, which represents a total pressure force of up to 14,000t. The drive consists of a hydraulically controlled plunger pump with electric pressure control and an electric motor of 90kW.
Packages of 1.8m x 2.6m x 1.8m
The pressure load consists of wet fibre cement panels that are separated by thin stainless steel plates. The total height of the load to be pressed is 1.8m and the surface area is 2.6m x 1.8m. This pressure load is moved into the press by means of a trolley.
As soon as the pressure load is inside the press, four rapid traversing cylinders will make sure that the other block, containing the whole load, including the underlying pressure cylinders, are swiftly pulled against the upper block of the press. During this rapid traverse, the six pressure cylinders are pulled out, whereby underpressure may be created. This put special requirements on the sealing. In the end, a triple sealing system with leak detection was opted for.
Checking 100 times per second
The press has been provided with a synchronising system consisting of four sensors, which monitor the position of the lower block. The sensors have an accuracy of five microns. The operation of the press is realised by means of an advanced PLC system, which ‘reads’ and processes the signals of the position sensors 100 times per second.
The four rapid traversing cylinders as well as the six pressure cylinders each have their own servo valve, which are driven by the PLC independently from each other. This way, the position of the cylinders can be controlled in a highly precise manner. As a result, the lower block of the press is kept perfectly level, both during the rapid traverse and during the actual compression, with a maximum deviation of 1mm between the corners of the lower block.
After the lower block has come to a standstill, this deviation is further reduced to a value below 0.2mm.The press is operated around the clock, making approximately 48 pressure runs each day, five days a week.
For more information, please contact HydrauRent.
