The present invention relates to a drier for a web of material, in particular for an offset printing machine, comprising an essentially closed housing with an inlet slot and an outlet slot for the web of material, while in the housing provision is made on either side of the web of material for air nozzles, which are fed via one or more of fans with the atmosphere in the housing, said housing also having at least one heating appliance provided with a combustion unit for heating the atmosphere inside the housing.
Such a drier is known, for example from German "Offenlegungsschrift" No. 2412446. In this known drier the combustion gases from the combustion unit are discharged to the outside via a heat exchanger, and the air circulating inside the housing is heated up by means of said heat exchanger. This known drier has a number of disadvantages, relating to the complex and expensive design, in which a large number of control valves are necessary, requiring expensive control and regulating devices. Besides, the heat exchanger takes up a large amount of space.
An object of the present invention is to provide a drier having a compact design and a high efficiency.
Another object of the invention is to provide a drier in which the exhaust gases can be discharged to the outside air without any problem.