Roundo PRH PRV plate straighteningmachines

ROUNDO
Plate straightening Machines
Type 
Plate straightening Machines Type PRH
The PRH machines are used for straightening of steel plates in dimensions within the machine's capacity. PRH machines are produced in a wide range of sizes for plate thicknesses from 1 up to 70 mm and for plate widths up to 4000 mm. The smallest plate size that can be straightened depends on the shape of the plates, but generally the minimum plate length is twice the top roll centre distance. The minimum plate width is limited by the feeding possibility, but since all ROUNDO machines have roller bearings, these machines can handle smaller widths than other types. Depending on size and execution the machines can be epuipped with three, four or eve bottom rolls and two, three oг four top rolls. Often the PRH machines are equipped with an extra pair of infeeding rolls, in order to get easy in feeding of the plate. This pair of rolls is also called pinching rolls.
The Pinching rolls optional
The purpose of the pinching rolls is to simplify the operation of the machine. They also improve the feeding of the plate through the machine. The top pinching roll is hydraulically adjustable up and down, and the lower pinching rоll is fixed. The pinching pressure can be preset and the floating function maintains a constant pressure against the un straightened plate. The position of the top pinching roll can be read by digital readouts on the control desk. straightening rolls
After the pair of pinching rolls, there are 5, 7 or 9 straightening rolls which will perform the actual straightening of the plate. The top 2, 3 or 4 straightening rolls are hydraulically and independently adjustable up and down by means of switches in the control desk. The lower 3, 4 or 5 straightening rolls are fixed. Each of the top straightening rolls has its own set of digital readouts showing their position.

Working principle
For example, when using a 7 roll machine, you would place the leadíng edge of the plate on the lower pinching roll and pinch the plate. Adjust the first top straightening roll down, so the roll bends the plate beyond the yield point. The next top straightening roll is adjusted to a position a little higher than the first one and the last top straightening roll is adjusted even further up. Depending on the required straightening tolerance, it may be necessary to pass the plate through the straightening machine two or more times.

MACHINE DESIGN
All welded plate frame, stress relieved and accurately machined.
Rolls
All forged steel rolls. As an option the rolls can be hardened and ground.
Support Rolls
The lower straightening rolls are supported in the middle by fixed support rolls to increase the thickness range of the machine. Some machines with short roll length are made without support rolls.
Bearings
All rolls are journalled in SKF speherical roller bearings, sealed and greased for many years of operation.
Drive
Smaller models
All bottom rolls are driven from a central gear box motor that transmits the torque via steel gears to the bottom rolls.
Laroer models
All bottom rolls aгe driven by separate high torque hydraulic motors with planetary gearboxes.
As an option the rolling speed can be infinitely variable from 0 7 m min.
Top roll adjustment
Each end of each top roll has a hydraulic cylinder that moves the roll up or down. The top rolls can either be adjusted parallel against the bottom rolls or tilted if required.
Hydraulic system
The hydraulic unit is placed on the machine and is
completely sealed, filled with oil when the machine is delivered.
Electric unit
The electric unit is placed on the machine, completely equipped when delivered. At installation, only one incoming power cable is required.
Control unit
The main control unit includes all push buttons, joysticks, digital readouts, etc. Two emergency stops are placed on the machine.