The corrugated cardboard sheet manufacturing system including a production state information acquisition device; a control value information acquisition device for acquiring control value information of a control element of a corrugated cardboard sheet manufacturing apparatus exerting an influence on the warp of a corrugated cardboard sheet; a warp information acquisition device for acquiring information of a warp amount of the corrugated cardboard sheet; a storage device for storing a performance data set including at least production state information, the control value information, and the warp information; a pre-control table storing a standard control value of the control element set in accordance with a production state; a correction table for correcting the standard control value to set an initial control value; an update device for updating the correction table by reflecting the performance data set; and control device for performing feedforward control of the control element using the initial control value.

The hot plate (11) includes an upper plate (61) joined to a lower plate (63) along respective sides parallel to each other. A heat transfer fluid circulation chamber (65) is defined between the upper plate (61) and the lower plate (63), with at least a first inlet (83) of the heat transfer fluid and at least a first outlet (87) of the heat transfer fluid. The lower plate (63) has two downwardly bent edges (63.2), extending along the sides of the upper plate joined to the lower plate. Stiffening ribs (79) are joined to the lower plate (63), along the heat transfer fluid circulation chamber, and to the downwardly folded edges (63.2s) of the lower plate (63).

A new method is disclosed for monitoring the operation of a corrugated board production plant, the method provides for detecting at least one operational parameter of a functional unit of the plant, for example a current absorbed by a motor. Then, the current value of a statistical function of the operational parameter is calculated in a current temporal window. The maximum value and the minimum value of the same statistical function are calculated based on historicized data of the operational parameter in question. By comparing the current value of the statistical function and the maximum and minimum values, a piece of information of predictive diagnostics is obtained.

A new method is disclosed for monitoring the operation of a corrugated board production plant, the method provides for detecting at least one operational parameter of a functional unit of the plant, for example a current absorbed by a motor. Then, the current value of a statistical function of the operational parameter is calculated in a current temporal window. The maximum value and the minimum value of the same statistical function are calculated based on historicized data of the operational parameter in question. By comparing the current value of the statistical function and the maximum and minimum values, a piece of information of predictive diagnostics is obtained.

The method includes the step of pulling the corrugated board along hot plates by means of an upper flexible member and a lower flexible member driven by two electric motors. By at least one electric parameter of the drive motor of the lower flexible member, the correct operation of the traction device and in particular the correct ratio of the linear feeding speeds of the two flexible members is checked. The method provides an iterative check of the controlled electric parameter and a possible correction of the speed of the flexible members to maintain the desired speed ratio.

The method includes the step of pulling the corrugated board along hot plates by means of an upper flexible member and a lower flexible member driven by two electric motors. By at least one electric parameter of the drive motor of the lower flexible member, the correct operation of the traction device and in particular the correct ratio of the linear feeding speeds of the two flexible members is checked. The method provides an iterative check of the controlled electric parameter and a possible correction of the speed of the flexible members to maintain the desired speed ratio.

The method includes the step of pulling the corrugated board along hot plates by means of an upper flexible member and a lower flexible member driven by two electric motors. By at least one electric parameter of the drive motor of the lower flexible member, the correct operation of the traction device and in particular the correct ratio of the linear feeding speeds of the two flexible members is checked. The method provides an iterative check of the controlled electric parameter and a possible correction of the speed of the flexible members to maintain the desired speed ratio.

The hot plate (11) includes an upper plate (61) joined to a lower plate (63) along respective sides parallel to each other. A heat transfer fluid circulation chamber (65) is defined between the upper plate (61) and the lower plate (63), with at least a first inlet (83) of the heat transfer fluid and at least a first outlet (87) of the heat transfer fluid. The lower plate (63) has two downwardly bent edges (63.2), extending along the sides of the upper plate joined to the lower plate. Stiffening ribs (79) are joined to the lower plate (63), along the heat transfer fluid circulation chamber, and to the downwardly folded edges (63.2s) of the lower plate (63).

The method includes the step of pulling the corrugated board along hot plates by means of an upper flexible member and a lower flexible member driven by two electric motors. By at least one electric parameter of the drive motor of the lower flexible member, the correct operation of the traction device and in particular the correct ratio of the linear feeding speeds of the two flexible members is checked. The method provides an iterative check of the controlled electric parameter and a possible correction of the speed of the flexible members to maintain the desired speed ratio.

Provided are a humidifying device and a corrugating machine whereby release of heat from heated water is suppressed and a liner paper is humidified. A humidifying device for humidifying a surface liner paper affixed to a core paper via a starch glue has a liquid application roller for applying heated water to the surface liner paper, provided downstream from a preheater for heating the surface liner paper prior to the affixing; and a chamber facing the peripheral face of the liquid application roller and provided with an internal space to which the heated water is supplied. The chamber further has an opening for supplying the heated water to the peripheral face of the liquid application roller, and is formed so that the length of the opening in the direction orthogonal to the axial direction of the liquid application roller is less than the diameter of the liquid application roller.