Most products need some kind of in-line post-processing after the reacting and mixing stages. In grease manufacture, the usual methods that we use in our projects are: Homegenising, filtering, de-aerating and packaging grease. Having the right equipment can be critical to the performance and appearance of the product.
These are the principle in-line machines:
The two main types of pump we use in our projects are gear pumps and progressing cavity pumps. Gear pumps are good over a wide range of temperatures and viscosities or grease consistencies. Progressing cavity pumps are equally good in handling hgh viscosities but have the additional advantage of being able to create a full vacuum on suction if fitted with a rubber stator. One issue to watch, though, is to ensure the stator has the right temperature rating to avoid it softening or melting when in use.
There are two main types of Colloid Mill that we normally use in our projects, one has a ribbed stator and rotor and the other has a smooth stator and rotor.
Ribbed stator and rotor combinations are popular with grease manufacturers as the actions pounds the grease as well as shearing it. The smooth type is useful if you need to know exactly what size you are milling to.
Some grease plants use a homogenisers instead of mills. A homogeniser consists of an exceedingly high pressure reciprocating pump feeding a spring loaded orifice. This gives shear in two planes instead of one and are regarded as being technically superior to colloid mills. However, they cost more and have a high wear rate, requiring regular scheduled maintenance.
We use basket, duplex and scraped surface self-cleaning filters.
These are popular for EP and Anti-Wear Grease manufacture where there are no solid powders in the mix, to remove undissolved soap or soap raw materials. This ensures the grease gives bearings quieter running in service than most unfiltered greases. It is sometimes a QA Requirement by certain customer.
We have a design of orifice type de-aerators for clarifying cloudy products that us unique to us. If necessary, we can incorporate a vacuum chamber to remove a greater proportion of air.
De-aerators can either be gravity or line-fed depending on the plant set-up. We can also incorporate automatic shut-off equipment to allow the de-aerator to double as a gravimetric filling machine.
Filling and Packaging Equipment
Generally, we favour gravimetric filling because it matches the units by which the grease is sold, but can do volumetric filling machinery for smaller packages if the need arises.