The most suitable location for automatic sample collection from moving streams is the discharge end of belt conveyor. Here the complete material stream is intercepted at regular intervals.
Sample increments are taken by an automatic mechanical sampler installed at the end of the head pulley and the sample is taken from the entire transverse cross-section of a continuously moving stream.
The mechanically operated oscillating screw type sampler collects representative samples when oscillating screw intercepts the material perpendicular to the material flow.
1. All particles in the lot to be sampled are accessible to the sample collection system and each individual particle gets an equal chance of being selected and included in the sample.
2. The oscillating screw intercepts complete cross-section of the falling stream at the head end.
3. The surface of the sampler aperture is always in line with falling stream trajectory thus maximizing the material contact and collection.
4. The speed of the oscillating screw sampler remains constant and does not exceed the belt speed.
5. The apertures of sampler is wide enough to prevent lump exclusions.
6. At the material receiving stage the sampler opening always has parallel edges.
7. The sample is collected from free flowing vertical stream.
8. On collection the sampler transfers the increment entirely without any loss or spillage and without any part of the sampler aperture restricting the collected material flow.
The swinging motion of sample collection system is relatively simple and ensures that the sampler screws intercept the complete stream.
The system eliminates ~80% of the sample collection errors (statistical errors) attached to the conventional manual sample collection systems and provides reliable samples.
The collected samples truly represent the sampled lot as the periodicity of sample collection is every 10-15 minutes (Programmable) and the samples are automatically collected from the entire falling stream of belt cross section.