Bitumen Laboratory Equipment: the Colloid Mill

Colloid Mill

Colloid Mill. Colloid mills are used for creation of bitumen emulsions in laboratory conditions. It consists of a body, a conical rotor on a shaft, a stator and a product supply funnel.

The body is made of cast metal with openings for anchor bolts to secure the mill to the bench. There are two horizontal shelves in the body with seats for shaft bearings.

The walls of the body has an opening for drive belt, a seat for the drive wheel and emulsion outlet. There is also a stator seat in the mill’s body.

The stator is case of carbon steel as two cylinders of different diameters, connected by the conical parts. There is a threaded opening in the small diameter cylindrical part for the load funnel and two openings for handles. The conical part features two openings for heating connectors. A conical part is installed into the larger threaded cylindrical part and secured with four bolts. The internal surface of this part is used for emulsification and must be thoroughly machined.

Steam or a hot liquid is supplied into the space between the outer surface of the part and the internal surface of the stator. A gasket seals the gap between the part and the stator. When the part is worn or damaged, it can be replaced.

The rotor is made of steel in the shape of a cut cone with thoroughly machined working surface. The corresponding part has the same conical shape. The toros is installed on the conical part of the shaft and is secured accordingly.

To prevent emulsion from entering the bearings, a guard disk with a downward bend is installed on a support and secured with a pin.

A wheel with a smooth surface for a flat belt is secured to the shaft.

The loading funnel is made of steel sheets with double walls for heating. The inlet is screwed into the stator. The heating jacket of the funnel is connected to the heating chamber of the stator by a flexible hose.

To prevent foreign metallic objects from entering the mill, the funnel is quipped with a 1 mm metal mesh.

The gap between the rotor and the stator is adjusted by vertical movement of the stator along the threading of the body, turning it by handles.

The mill operates as follows. Materials (bitumen and emulsifier solution) are supplied to the funnel, and from there into the gap between the rotor and the stator, where the materials are pulverized and emulsified. The emulsion is ejected to the outlet by rotating vanes.

After operation, the mill is flushed with a hot emulsifier solution. The funnel is removed, the stator is extracted and all surfaces are thoroughly cleaned.