Diaphragms, mill shell linings and grinding balls

The efficiency of ball mills can be significantly increased by the quality of your components. For this reason Christian Pfeiffer continues to develop their mill components, enriching the market again and again with their innovations. In the process, the focus is on high functionality and wear resistance together with low specific energy consumption, low maintenance needs, and high availability. Here you can read everything about our diaphragms, slotted and backside plates, mill shell linings and grinding balls.

Diaphragms
With innovative Monobloc® construction

Reduced energy needs, increased efficiency: The installation of a diaphragm can increase the economy of a grinding plant enormously. The Monobloc® frame developed by Christian Pfeiffer is very stable, durable, and especially tough in use. This diaphragm construction is seen as today's most advanced state-of-the-art solution for modern grinding plants.

Intermediate diaphragm

Material flow control and grain size limitation

Thanks to the material flow control and the limitation of the largest grain size by the intermediate diaphragm, the material stays in the first grinding compartment until it reaches optimum size; only then it moves into the second compartment  The separation of air and material flow, a major development by Christian Pfeiffer, ensures that so-called dead zones (zones without material being ground) directly behind the intermediate diaphragm are avoided. The result is a clearly more efficient grinding process.

Technical details

  • Separation of the ball mill into two (or three) compartment using the intermediate diaphragm
  • Each compartment is filled with different ball charges and sizes
  • Optimum material flow control and grain size limitation
  • Unique separation of air and material flows in the low-wear material flow arrangement: Avoidance of dead zones and lower wear on the grinding balls on the intermediate diaphragm – use of the entire grinding length of the second (and third) grinding compartment
  • 'Floating' installation reduces tension between the mill tube and the diaphragm structure. In this way: There is no tension between the intermediate diaphragm and the mill tube, the mill tube is stabilized, while at the same time, relative movements and deformations of the diaphragm are avoided
  • The structure of the intermediate diaphragm in the Monobloc® version supports the mill tube and works against deformation
  • Easier maintenance and replacement of main wear zones through division of the slotted and backside plates into two to four rings

Discharge diaphragm

Individual adjustment to the grinding plant

The discharge diaphragm allows the ground material to pass, but retains the grinding balls in the grinding chamber. Christian Pfeiffer adjusts the diaphragm individually to the existing grinding plant, fixing it either on the discharge mill head or floating on the mill shell.

Technical details

  • Ground material passes through the intermediate diaphragm, grinding balls are retained
  • Fixation on discharge mill head or on the mill shell possible
  • Adjustment of the inner diaphragm plates enables adjustment to the required maximum mill filling level
  • Easier maintenance and replacement of main wear zones through division of the slotted plates into two to four rings

Open lifter diaphragm

For mills with integrated drying chamber

By means of the open lifter diaphragm, the drying chamber integrated into the mill tube is separated from the grinding compartment. The steel grades used can easily withstand the up to 400°C hot gases found in the drying compartment.

Technical details

  • Separation of grinding compartment and drying chamber integrated into the mill tube
  • Use of steel grades with almost identical thermal expansion coefficients, in order to withstand the high temperatures (300–400°C) and high axial pressure
  • Extremely high mechanical and thermal loads can be absorbed
  • Adjustment of the diaphragm plates enables the adjustment of the central opening to the required maximum mill filling level
  • Construction of the diaphragm in Monobloc® version: supports the mill tube and resists deformation. Can also be supplied in segmented design
  • Easier maintenance and replacement of main wear zones through division of the slotted backside plates into two to four rings

Double outlet diaphragm

For mills with central discharge

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.

Technical details

  • For mills with central discharge (opposite material flow direction)
  • Optimum material loads in the grinding chambers through special retention rings in the diaphragm
  • Adjustment of the diaphragm plates enables the adjustment of the central opening to the required mill filling level

Slotted and backside plates for diaphragms

Hardened rolled steel and innovative design

All diaphragm plates from Christian Pfeiffer are produced using highly wear- and breakage resistant rolled steel, which is a superior material compared to plates produced using cast material. The innovative design of the slotted and backside plates makes the entire grinding process even more efficient, and ensures a long service life for the equipment.

Technical details

  • Manufactured using highly wear and breakage resistant special rolled steel with up to 60 HRC
  • Plate slots with optimum narrow conical openings for optimum material flow and high process stability prevent natural blockages: The material is transported onward only after it has been sufficiently ground.
  • Innovative fastening system: Bolt fastening with conical swages ensure accurate fitting for the plates. Efficient use of the plate up to a residual thickness of 8–10 mm. Utilization rate of 75% compared to 60% in conventional systems. Thanks to the use of tear-off bolts, fitting errors are effectively reduced and the plates are securely fixed to the frame. 
  • Long service life thanks to simple maintenance and partial replacement of the wear parts: Depending on the mill diameter, the slotted plate construction is divided into two to four rings. In the event of wear, only those plate rings that are most affected need to be replaced
  • If required, special slotted plates with lifters for those areas subjected to the most wear

Mill shell linings
Innovative shape for dynamic grinding movements

The quality of the shell lining is decisive for the production potential of the grinding processes, because the dynamics of the grinding media movement inside the mill is mainly defined by the shape of the mill shell lining. For this reason, Christian Pfeiffer optimally designed shell linings which, thanks to different fastening systems (bolted lining, semi-bolted lining, and boltless lining) can be individually tailored to specific mill requirements.

Progressive activator lining

Improved impact energy in the first grinding compartment

The progressive lifting shape of the lining is ideal for the grinding process in the first compartment. Here the material is ground using grinding balls with a larger diameter. The activator lining transports the grinding balls upwards with minimum slippage, thus producing optimum impact energy.

Technical details

  • Greater lifting heights produce higher impact energy
  • Distribution of the ball load, so that the material is moved effectively into the material bed
  • Controlled wear of the lining as a result of the grinding balls rolling over the lifters: The profile and effectiveness of the liner remain unchanged

Classifying lining

Efficient grinding in the second grinding compartment

The classifying lining provides efficient finer grinding of the coarse ground material. In the second compartment the material is primarily ground using pressure and friction, whereby the classifying lining retains the grinding balls with the largest diameter at the beginning of the compartment and the successively smaller balls at the end of the grinding path.

Technical details

  • Efficient grinding: Balls with the largest diameter are retained at the beginning of the compartment, balls with the smallest diameter at the end of the grinding path
  • A combination of classifying with two types of lifter plates is possible, with wave liners or progressive activator plates. Both kinds of lifter plates lead to a cascading motion of grinding balls, and an optimum material transport through the second compartment

CSL lining (compact spiral lining)

For second grinding compartment or mono-chamber mills

The compact spiral lining is mostly used in mono-chamber mills, or mills with a long second grinding compartment. The large number of progressive activator plates means that the ball load is moved optimally. The plow plates increase the energy transfer once again, creating a certain moderate sorting effect for the grinding balls, which improves the grinding power inside the ball charge.

Technical details

  • Designed for mono-chamber mills and mills with a second grinding compartment
  • In comparison with conventional linings, there is a higher energy transfer per ton of grinding balls as a result of the balls being mixed: The periodic interruption of a pure rolling movement by the grinding balls through the plow plates improves the grinding effect of medium-sized particle sizes
  • Because of the spirally arranged plow plates for this lining version, a completely bolted mill cylinder is definitely required.
  • A combination of two types of lifter plates is possible, with wave liners or low lifter plates

Drying chamber elements

For the drying chamber of raw mills

Drying chamber elements are used in raw mills, where a pre-drying of the feed material is required. Their function is to pick up the moist feed material and to transport it into the hot gas airflow. This way an effective drying of the material is achieved.

Technical details

  • Variable lifter angle depending on the moisture of the feed material
  • Variable versions of wear protection depending on the abrasiveness of the feed material
  • Bolted fastening for safe and easy installation and dismantling

Allmax® grinding balls
Wear resistant due to high-alloy steel

The Allmax® grinding balls are exceptionally wear resistant, thanks to the use of high-alloy steel with 11 to 19% chromium content. In the course of years of research and development, the alloys have been optimally adjusted to market requirements.

Technical details

  • Available sizes: from 17 to 100 mm diameter
  • High hardness level from 60 to 65 HRC
  • A horizontal casting process, together with regular chemical and microscopic tests, guarantees the breakage resistance, an optimum geometric shape, ideal microstructure formation, complete saturation in the gating area, and a casting without voids or cavities.
  • The Allmax I® grinding ball (11 - 13% chromium content) is especially suitable for grinding cement (raw material and clinker), especially in the 2nd and 3rd compartment of a tube mill for cement and raw meal grinding
  • The Allmax II® grinding ball (17 - 19% chromium content or more) is especially suitable for use in the first grinding compartment in raw meal and cement mills