Mills with central discharge are fitted with a double outlet diaphragm. The material is transported from both head sides of the mill towards the diaphragm, then out through the openings in the mill shell.
Modern diaphragms are designed to control the material flow and balance the material level in the first grinding chamber. The special feature of the Christian Pfeiffer intermediate diaphragms is that it directs the material into the second chamber separately from the air flow. This separation of material and air flow means that there is no unused zone behind the diaphragm. The material is fed directly into the second chamber at the backside of the diaphragm. As a result, the effective grinding length of the mill is fully utilized. In many cases, an increase in production of 3 - 6% can be achieved by the intermediate diaphragm MONOBLOC.
The structure of a diaphragm has usually a service life of 10 years. Thanks to the Christian Pfeiffer MONOBLOC design and the floating connection, our diaphragms achieve significantly longer service lives in practice. The slotted and backside plates are replaceable wear parts that are highly dependent on the ground material.
According to the customer, the structure of the oldest Christian Pfeiffer diaphragm was in use in Latin America for 40 years.
The width and size of the slots define the material throughput and limit the maximum particle size that can pass the diaphragm. If the size reduction is insufficient, coarse particles get stuck in the slots of the diaphragm plates and become lodged. This reduces the throughput capacity and disrupts plant operation. It is therefore important to design the slots in such a way that material cannot get stuck permanently. Thanks to the circumferential slot arrangement and the milled groove for ball guidance, the cleaning effect by the grinding balls is very high. The material that has settled in the slots are pressed through by the passing balls and do not remain in the diaphragm.
Making grinding processes as efficient as possible is a science in itself – one to which we dedicate our entire expertise and spirit of innovation. From the invention of the first MONOBLOC diaphragm to the technical fine-tuning of the separator QDK. How we became what we are today.