Application:

Tumbling barrels are used to clean iron and steel castings by rubbing. The cleaning process takes place in a rotary barrel by means of abrasive iron or steel media in the form of very fine star-shaped castings.
Tumbling barrels are used to clean:

• small iron and steel castings of simple and compact shapes,
• thick-wall medium-size castings of not complex shapes,
• all kinds of forgings,
• any steel parts of small sizes and compact shapes,
• castings and steel parts which are not very demanding in respect of their appearance.

Considering tumbling barrels of batch operation type DOZAMET – Nowa Sól offers:

• the OB-750 tumbling barrels (of barrel inner dia. 725 mm),
• the OB-1000 tumbling barrels (of barrel inner dia. 1000 mm).

To increase capacity of tumbling barrels DOZAMET offers additional equipment for mechanical loading and unloading of objects to be cleaned. Tumbling barrels of continuous operation are much more efficient than the barrels of batch operation because they do not require breaks necessitated by loading or unloading.
Cleaning is effected in rotary horizontal or inclined barrels. Cleaning action results from:

• rubbing of objects exclusively against one another,
• rubbing of objects against one another with the help of additional abrasive media.
• The following materials can be used as abrasive media:
• fine hardened iron or steel castings in various shapes, most often stars of wavy surface,
• rejected small castings,
• disintegrated parts of gating systems,
• other abrasive media required in cleaning processing, ex. liquids. 

Advantages:

As the upper part of cleaned load descends, objects of the load mutually dislocate each other. That phenomenon brings about rubbing and hitting of elements of the load against one another. The process of mutual dislocation results in:

• cleaning of load,
• polishing of cleaned elements,
• breaking sharp edges,
• rounding off sharp edges.

A slight inclination of a tumbling barrel intensifies the process of mutual dislocation of elements thus shortening cleaning time and making it more efficient.
Use of abrasive media also makes cleaning more efficient and accelerates cleaning process by approx. 25%. Abrasive media of small dimensions enter cavities and recesses difficult to access, fills empty spaces between elements thus increasing abrading area and results in quicker and more precise cleaning. The amount of abrasive media, most often iron tumbling stars, constitutes 3-10% of the cleaned load weight. Dimensions of stars generally range from 20 to 65mm.
In consideration of operation mode tumbling barrels can be divided into:

• tumbling barrels of batch operation,
• tumbling barrels of continuous operation.

Tumbling barrels of batch operation are filled with a load up to approx. 75% of barrel capacity. Performance of tumbling barrels of batch operation depends on size and shape of load, amount of abrasive media and mechanisation degree and loading and unloading. Ex. mean time of cleaning (tumbling) castings is:

	Unit	Iron castings	Steel castings
Very small castings	h	~0:45	~1:30
Small castings	h	~1:00	~2:00
Medium castings	h	~1:20	~2:30

Technical specifications:

	Unit	OB-750	OB-1000
Tumbling barrel capacity	m3	0,68	1,35
Nominal weight of load	kG	1500	2700
Max. unit weight of castings	kg	50	60
Mean tumbling time of load	h	1,25 ÷ 1,75	0,6 ÷ 1,3
Approx. capacity in 8h operation at manual loading and unloading	kG	3000 ÷ 6000	9000
Required amount of abrasive media in barrel	kG	130	250
Drive motor power	kW	7,5	7,5
Required capacity of dust extraction equipment	m3/s	0,36	0,83
Required vacuum at connection pipe	Pa	550	550

An example of diagram of the OB-1000 Tumbling Barrel