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How to choose a Weiss chamber to suit your applications

We often get enquiries from potential Customers who know they need a test chamber but don’t know where to start to decide what type of chamber they want. In this article we show you the main considerations and where they lead you in the Votsch range. This range is vast so we have narrowed it down by excluding parts of the range and concentrated on the most popular parts of the range. Amongst the parts excluded are ovens that have no cooling, vacuum ovens, thermal shock chambers, corrosion, emission, light testing, splash, stability, extra-large, PV testing and vibration chambers.

Weiss Technik brochure cover

First let us explain the chamber type nomenclature:

W: Weiss.

T: Temperature only, K: Climate i.e. with humidity control.

S or L (if present): Special i.e. non-standard, or Laboratory size.

3 denotes third generation i.e. Simpac control.

-XXX: these 2 or 3 numbers tell us the internal volume e.g. 40 = 40 litres, 1500 = 1500 litres.

/0, /40 or /70: /0; can reach 0°C and is suitable for constant temperatures, /40; can reach -40°C, /70; can reach -70°C.

-X: this may be present if it is a special chamber and denotes the ramp rate this chamber can achieve when empty e.g. -5= 5°C/min.


An example would be WK 3-480/70/15. This third generation special Weiss chamber controls humidity as well as temperature. It has a 480 litres test space, can cool to -70°C and can ramp up and down at 15°C/min when empty.


And so to the basic questions which would mostly apply to all manufacturers:


  1. Is humidity control required? WT or WK
  2. What low temperature is required? ≤ 0, ≤-40 or ≤-70°C?
  3. What is the highest temperature required?
  4. What test space dimensions/volume are required?
  5. Is a special ramp rate required? If so with what maximum thermal mass and what dissipated heat, if any?
  6. What ramp rates will be required with this maximum thermal mass?
  7. Do the ramps need to be linear?
  8. Will the test samples emit any corrosive or combustible gases/liquids? Do the test samples have explosive potential? (ATEX considerations)
  9. Will any option be required e.g. extra shelves, wheels, door with window, extra ports, low dew points.


For safety reasons if combustion or explosion is possible a detailed checklist is filled out and submitted to Votsch for a detailed quote.


Usually DACTEC can issue a technical and a costed quote within 24 hours after we have lead the Customer through the above considerations and ensured that the chamber(s) offered will perform the tests required.






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