Roll arrangement and method for cooling a roll

A roll arrangement for use in a machine for producing a fibrous material web comprising:

• a roll having an axis and two axial faces,
• the roll further including a hollow space positioned inside the roll, the hollow space being substantially impermeable to gas and liquid;
• a heating device heating a circumferential surface of the roll;
• a heat exchanger arranged in the hollow space;
• a vaporizable fluid positioned in the hollow space;
• and
• axial bores coupled to the hollow space arrangement and positioned to receive the liquid phase of the vaporizable fluid from the heat exchanger.

A method for cooling a roll jacket of a roll for use in a machine for producing a fibrous material web, the roll jacket being heated by an exterior heat source, the roll including a hollow space at least partially filled with a vaporizable fluid, the roll being coupled with a heat exchanger, and axial bores being coupled to the hollow space, the method comprising:

• vaporizing the vaporizable fluid in the hollow space;
• condensing the vapor on the heat exchanger by a coolant flow through the heat exchanger;
• rotating the heat exchanger within the hollow space to centrifugally disperse the condensed liquid within the hollow space;
• and
• receiving the condensed liquid from the heat exchanger in the axial bores.

A method for maintaining a uniform temperature of a roll for use in a machine for producing a fibrous material web, the roll being heated on the exterior of the roll via an external heating device, the roll including a hollow space partially filled with a vaporizable fluid, the roll being coupled with a heat exchanger, and axial bores being coupled to the hollow space, the method comprising:

• vaporizing the vaporizable fluid in the hollow space;
• condensing the vapor on the heat exchanger;
• rotating the heat exchanger within the hollow space to centrifugally disperse the condensed liquid within the hollow space;
• and
• receiving, in the axial bores, the condensed liquid from the heat exchanger.

A roll arrangement for use in a machine for producing a fibrous material web comprising:

• a roll having an axis and two axial ends, the roll including a hollow space arrangement on an interior of the roll;
• a heating device that acts on an exterior of the roll;
• a heat exchanger positioned in the hollow space arrangement;
• a vaporizable fluid positioned in the hollow space arrangement, the vaporizable fluid having a liquid phase and a gas phase;
• and
• a switch for selectively switching off the heat exchanger while the heating device acts on the roll exterior.

A roll arrangement for use in a machine for producing a fibrous material web comprising:

• a roll having an axis and two axial faces,
• the roll further including a hollow space positioned inside the roll, the hollow space being substantially impermeable to gas and liquid;
• a heating device heating a circumferential surface of the roll;
• a heat exchanger arranged in the hollow space;
• a vaporizable fluid positioned in the hollow space;
• and
• a switch for selectively deactivating the heat exchanger while the heating device is heating the circumferential surface of the roll.