Rosahl MDL-3 Electric Micro-Dehumidifier

The MDL-3 by Rosahl is a compact flat-membrane dehumidifier module for volumes of up to 0.5m³ (500l)..

Operation Principle

Like all Rosahl dehumidifiers the MDL-3 is based on a solid-state polymer membrane. When supplied with a 3V DC voltage, moisture on one side is being decomposed into Hydrogen ions and Oxygen, the Hydrogen ions pass the membrane and recombine with air Oxygen to moisture again on the other side and get discharged.

Storage of 3D-Print Filament Spools

With an applicaple air volume of 500 liters the Rosahl MDL-3 membrane is suitable for storage of single filament spools e.g., in a 50-80 litre "Kreher® Waterproof Storage Box" with space for ~15-20 spools (alternatively Ikea "Samla" box, which has to be sealed separately). With pre-dried filament spools (especially spools made of cardboard contain quite high moisture) a continous storage at approx. 15% rH and less is achievable. We made a 3D printable mounting frame for the MDL-3 membrane plus USB-C power supply module, see the further product images. The 3D models can be downloaded on Printables.com.

Which Membrane Suits What Application?

The following table reflects our own applications with different membranes and usage scenarios in our climate zone with max. 65-70%RH and could serve as a guide for membrane selection.

(1) This is the specified applicable volume by the manufacturer. For 3D print filament storage at low humidity levels around 15%, we recommend to oversize the membrane at least by a factor of 5 or 6. Achievable end-humidity depends on various factors like box sealing, temperatur, outside humidity level. In regions with high air humidity it might be beneficial to oversize the membrane more.
(2) The Bambu Lab AMS comes with some manufacturing variations and can be less properly sealed as stated. Given this, also an M-1J1R or M-2J1R can give decent results but it is recommended to carefully check for potential leakages and proper/tight gasket sealing before chosing a membrane size. It might hence be beneficial to oversize the membrane more. If in doubt, contact us prior to selecting/ordering.

Power Supply

The Rosahl MDL-3 dehumidifer requires a 3V DC supply voltage and draws in continous operation i.e., when the moisture level in the volume stabilized to a low level, just around 2W power.
Due to the membrane being intrinsically hygroscopic, it absorbs humidity if no supply voltage is present. This moisture needs to be discharged on startup and leads to a significantly higher inrush-current that the regular operating current. During startup the supply voltage shall still not drop below 2V, otherwise moisture discharge is not possible or significantly delayed. Suitable current supplies are fold-back current limiting sources, which regulate the output current further down than pure constant current sources and hence maintain a certain output voltage. We provide suitable USB-C voltage regulator modules with fold-back current limiting, which can be used stand-alone or mounted into our 3D-print mounting frame/covers.

• USB-C 5V->3V/3A voltage regulator module for Rosahl MDL-3 dehumidifier

Technical Parameters MDL-3

Applicable Volume	~0.500m³
Dehumidifying Performance	4g/day
Supply Voltage	2.9-3.3VDC
Power Consumption	2W (20°C/60%rH)
Rated Current	900mA (dep. of rH)
Inrush Current	7A
Operating Temperature	-10°C - +50°C
Connecting Type	Solder/flat connectors

 

 

Further Information

• MDL-3 Produktspezifikation
• Instruction Manual

Scope of Delivery

The Rosahl MDL-3 dehumidifier comes as single unit.

Complete Kits

A full kit with the MDL-3 membrane, VREG2 USB-C power supply module and assembly material is available as well.

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Manufacturer Information
RYOSAI TECHNICA CO., LTD., 8-1-1 Tsukaguchi-Honmachi, Amagasaki-City, Hyogo, 661-0001 Japan, Email: ryosai_sales@ryoyo.co.jp