Sampling apparatus for use in explosive environments, a dryer comprising such a sampling apparatus, and method of estimating the flowability of a sample

A dryer comprising:

• a drying chamber having an upper end and a lower end;
• an inlet for a liquid feed to be dried;
• an outlet for dried particles at the lower end of the drying chamber;
• and
• a sampling apparatus comprising:
• a product stream of particles of a mean size of up to 500 μm;
• a displaceable arm having a sample container, the displaceable arm having a first position where the sample container is inserted into a first zone such that a sample of particles is collected into the sample container, and a second zone where the displaceable arm is outside the product stream, wherein the second zone is within a housing with an opening for the displaceable arm;
• and
• an interface between the first zone and the second zone, the interface comprising one or more of a closable member, a gate valve, an air knife, a lock, or an access gate filled by the displaceable arm,
• wherein the first zone is within the drying chamber or in a duct attached thereto.

A method of estimating a flowability of a sample of particles, the method comprising:

• providing a sample of particles having a mean size distribution between 10 μm and 500 μm and a moisture content between 0.5% and 7%;
• placing the sample of particles in a sample container with a vibrator;
• vibrating the sample container at a first frequency between 1 Hz and 100 kHz;
• measuring a height of the sample in the sample container until the height of the sample no longer decreases upon further vibration;
• and
• estimating the flowability of the sample by comparing a first height measurement, an intermediate height measurement, and a final height measurement.