For yeast driers type 500G and larger hydraulic motors are provided, ensuring an absolutely uniform rotation of the cylinder. The hydraulic unit also controls the function of the scraper bar and the operation of the dipping trough.
The driers type 50 - 400 are supplied with slip-on gear drive, while the scraper bar and dipping trough are operated hydraulically. The speed of the cylinder is infinitely variable by means of an adjustable drive.
Construction and Operation
The Ponndorf Yeast Drier is a so-called Single Cylinder Sump Drier. The rotating cylinder picks up a thin yeast coating when touching the yeast in the so-called sump or trough beneatch the cylinder. Only a small part of the yeast in the trough is taken by the drier. The remaining yeast flows to the overflow channel and is returned by a pump to the autolysis vessel. Thus sedimentation and the forming of lumps is avoided. The yeast coat dries on the heated rotating cylinder and is scraped off by a hydraulically operated blade and falls into a crushing screw. A fan further pulverizes the crushed yeast and blows it into the dry yeast storage silo for further packaging by means of a bagging scale.
The drier cylinder is heated with steam. The steam inlet and outlet is a maintenance-free connecting head. A vapour hood is installed above the cylinder with an exhaust fan for the hot vapour.
The plant can operate without permanent supervision. All components of the drying plant are mounted on a common base frame making additional foundations unnecessary.
The dipping trough can be cleaned during operation. The trough is hydraulically lowered until all the yeast flows into the overflow channel. The yeast scraping blade may be exchanged during operation as well as the blade is simply inserted in a pocket and can be changed without any tools.
For the driers type 400 - 1200 the drier cylinder is made of cast iron and for the driers type 50 - 300 of steel. In both cases the cylinder surface is finish-ground.