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For dry foods, wet cleaning is not always the best solution. How to clean hygienically without introducing new microbiological risks.

Flour dust does not only arise during cleaning. The cause often lies in filling, packing and emptying flour bags.

A laboratory result is only as reliable as the sample it is based on. With powders and granules, the sampling determines whether a test result says anything about the actual product quality.

A homogeneous blend in the blender is no guarantee of a homogeneous end product. During discharge, conveying and transfer to the tablet press, powder segregation can occur, causing variation in API concentration.

An automatic powder sampler can work correctly and still collect a non-representative sample. Segregation, the position of the sampler and the sampling method determine how reliable the result is.

Vacuum drying removes electrolyte solvents from battery material. With controlled condensation and closed filling, emissions and dust stay limited.

An automatic powder sampler can work perfectly and still give a distorted picture. Sampling from a moving product stream and taking several increments are the basis for a reliable result.

A centrifuge with irregular discharge loses stability in the separation process. Air entrainment, an undersized pipe and insufficient venting are the most common causes.

Negative pressure protects the operator from potent powder, while sterile product protection calls for HEPA filtration and controlled airflow. With a well-designed pressure cascade and validated containment, you can combine both goals.

Can meropenem be produced in an existing cephalosporin facility? The answer depends on demonstrable physical segregation, not just on cleaning between batches.

A homogeneous blend is not automatically a homogeneous end product. Where segregation occurs during filling and how to prevent it.

ATEX zones determine which equipment you may use where explosive atmospheres can occur. For gas, zones 0, 1 and 2 apply. For dust, zones 20, 21 and 22 apply. The zone determines the minimum equipment category.

Gas or dust?

Gas explosions are caused by flammable gases, vapours or mists. Dust explosions occur when combustible dust is suspended in the air in sufficient concentration. In powder handling, dust is the main concern, so the dust zones matter most.

The dust zones 20, 21 and 22

• Zone 20: an explosive dust cloud is present continuously, for long periods or frequently.
• Zone 21: an explosive dust cloud occasionally occurs during normal operation.
• Zone 22: an explosive dust cloud is not expected and only occurs briefly in case of a malfunction.

How is a zone determined?

The zone follows from the likelihood and duration of an explosive atmosphere. This assessment belongs in the explosion protection document. Determine zones per installation and per operating situation.

Which equipment belongs to which zone?

• Zone 20: at least category 1D (Da).
• Zone 21: at least category 2D (Db). Category 1D is also allowed.
• Zone 22: at least category 3D (Dc). Category 2D or 1D is also allowed.

Equipment with a higher category is always allowed. The category is shown on the nameplate. Check it before you order.

Why this matters for powders

Powders dust up during filling, transport and mixing. Fine fractions stay airborne longer. That is why the dust zone often determines the choice of motors, sensors, lighting and conveying equipment. Static electricity is an additional risk, so make sure the installation is properly earthed.

Frequently asked questions

What is the difference between zone 20 and zone 22?

In zone 20 the explosive dust cloud is present continuously or for long periods. In zone 22 it only occurs briefly in case of a malfunction.

Which category do I need for zone 21?

At least category 2D. Category 1D is also allowed.

Who determines the zone classification?

The owner of the installation, based on a risk assessment. We help with equipment selection and documentation.

Want to know which category you need for your installation? Contact us.