Rosahl RS1 Electric Micro-Dehumidifier

The RS1 by Rosahl is a compact flat-membrane dehumidifier module for volumes of up to 5 litres.

Operation Principle

Like all Rosahl dehumidifiers the RS1 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 5 liters the Rosahl RS1 membrane is suitable for storage of single filament spools e.g., in 4 litre "cereal boxes". Picture 4 shows such a solution with 3D-printed mounting parts (cover/plug with RS1 mounting hole, cover for power supply module with sealing, PTFE tube outlet, spool rollers up to 67mm width, cover plug for PTFE tube when not used). The STL files for these are available for download at Printables.com and can be printed on your own. 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.

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 RS1 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 0.2W 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/500mA voltage regulator module for Rosahl RS1 dehumidifier

Technical Parameters RS1

Applicable Volume	~5000ccm (5l)
Dehumidifying Performance	210mg/day
Supply Voltage	2.9-3.3VDC
Power Consumption	220mW (20°C/60%rH)
Rated Current	105mA (dep. of rH)
Inrush Current	1.8A
Operating Temperature	-10°C - +50°C
Connecting Type	Soldering

 

 

Further Information

• RS1 Product Specification
• Instruction Manual

Scope of Delivery

The Rosahl RS1 dehumidifier comes as single unit with gasket.

Complete Kit

A complete kit with RS1 membrane, VREG1 USB-C power supply module, assembly material and hygrometer 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