The key link of the coal analytics procedure is sampling according to the standard. The reliable sample is the prerequisite for getting a reliable coal analytic result. What is coal sample? Coal samples are composed of several sub-samples taken from the coal conveyor belt or from railcar, truck with coal. The coal sample represents the average quality of the corresponding coal during sampling. As we know, the ASTM standard stipulated the sampling method includes how to make the sample from the conveyor belt and truck, railcar with coal, which sampling tools can be used and how to arrange the sampling point. So Top-Sampler is pleased to introduce some coal sample machines to you.
There are two main types to make coal sample that are auger sampling system and the cross belt sampling system. The auger sampling system is used for the railcar and truck with coal and other bulk material like iron ore, wood pellets, etc. the cross belt sampler is used in the conveyor belt.
Due to the use of artificial sampling on large coal conveyor belts neither collects representative samples of coal nor is it safe, it is necessary that the coal moving stream applies to the mechanical sampling machine. What is cross belt sampler? How to choose cross belt sampler? Top Sampler will introduce the cross belt samplers for you.
Multi-stage sampling system
At first, we would like to introduce the multi-stage sampling system. The multi-stage sampling system is a complete coal sampling procedure includes the sampling system, sample preparation system and the residue return system. The common sampling systems are the secondary-stage sampling system and tertiary-stage sampling system.
The secondary-sampling system is applied to the coal flow lower than 2000ton/ hour and the material size is smaller than 100mm. In the secondary-stage sampling system, the primary sampler sends the sample to the conveyor feeder and then to the sample crusher to be crushed. Then these samples will send to the secondary sampler so that require the final sample and the sample will collect in the bottles.
The tertiary-stage sampling system is applied to the coal flow higher than 2000 ton/ hour and the material size is bigger than 100mm. there is a third sampler in the tertiary-stage sampling system. The primary sampler makes the first sample to the secondary sampler through the conveyor belt and requires the sample which meets the ASTM D 2234. Then the samples will be sent to the sample crusher and the third sampler so that requiring the final sample finally.
Types of cross belt sampler
Nowadays, there are two types of cross belt samplers in the market that are head belt sampler and the central belt sampler. Both of the head belt sampler and the central belt sampler are the primary sampler.
Central belt sampler
The central belt sampler is used in the middle of coal conveyor belt. The main character of the central belt sampler is scrape sampler. The scrape sampler cuts the moving coal stream crosswise. The central cross belt sampler has a simple structure, and the mass of the single sample is smaller. So the central belt sampler is applied to the small sampling system and middle-sized sampling system.
Head belt sampler
The head belt sampling system is composed of rotating hopper, rotating cutter and feeder. The head belt sampler is the main machines in the head sampling system and it is used to the head of the conveyor belt. ASTM D 7430 has stipulated the sampling device speed that the speed of the sampling device should under 457mm/s so that the head belt sampler can avoid remaining the coal bulks on the conveyor belt after the head belt sampler worked.
Sampling equipment selection
How to choose the suitable sampling machine? How to judge this sampling equipment is suited for you? The determinant is can the sampling equipment get the representative sample or not. You should also consider these elements:
First, you should consider the coal types and the sampling unit. A sampling unit is one of the units into which an aggregate is divided for the purpose of sampling. Each unit is regarded as individual and indivisible when the selection is made. The sampling unit and the coal types are the basic elements to determine the number of subsamples. And the subsample is the key element to ensure the sample precision.
Second, you need to consider the top size of coal bulk. The top size of the coal is the only condition to determine the open size of the sieve mesh.
Third, you need to consider the moisture and density of coal. These parameters are determined the size of the sample.
Besides, you should consider what kind of sample preparation system machines to support your sampling system machines.
Top Sampler provides sample preparation system machines like sample crusher and vibrating screen machine. You can contact us directly. We are pleased to answer your questions!
