Size press having a detachable throttle

The invention relates to a method and device in a size press in which a nip is formed by a pair of rolls. A paper or board web is passed through the nip. The rolls are provided with surface-sizing units for applying films of size or coating agent onto faces of the rolls. Each surface-sizing unit comprises an application zone defined by a coating member, a front edge of the application zone and a feed chamber. The coating agent, such as a size, is fed, through holes or corresponding nozzles that have been formed into a wall of a feed pipe, into the feed chamber under pressure out of the feed pipe which is arranged transverse to the machine direction. The coating agent is fed out of the feed chamber into the application zone through a throttle placed between the feed chamber and the application zone. The throttle comprises a perforated plate or equivalent which extends across the width of the machine and which is detachably fixed to the frame constructions of the surface-sizing unit by fastening members.