What are the adjustable fan speed and air flaps used for in Memmert ovens?

In Memmert Fan assisted ovens (UF series) the fan speed and air flap positions can be adjusted - but what affect does this have on the system, and when would you use this feature? [caption id="attachment_7741" align="aligncenter" width="301"] The UF110 Memmert fan assisted laboratory oven[/caption]

Fan - for temperature uniformity

The fan inside fan assisted ovens helps to circulate the air around the chamber, giving a more uniform temperature throughout (avoiding "hot" and "cold" spots). When the unit is heating up to a set target temperature, the fan is usually set to 100% to keep the air moving and create this uniformity. This might later be turned down once temperature has been reached. [caption id="attachment_6903" align="aligncenter" width="428"] Air flow patterns vary in fan assisted or natural convection ovens, but all Memmert units ensure great temperature distribution through several key technical features[/caption] There are also other ways in which Memmert units minimize temperature variation - see our previous post about this here. In UF ovens the fan is adjustable in 10% steps. On single display models this must be changed manually, on twin display models this change can be programmed in as part of the overall squence of events. This is just one of the differences between single and twin display types. Remember if you're working with powders, or want to avoid strong evaporation a natural convection oven may be more suitable than a fan assisted oven - see our previous post about this here.  

Air Flaps - for cooling, air exchange or venting

The air flaps on the UF series ovens can be adjusted in 10% steps, again this must be manually changed on single display models but can be pre-programmed on twin display types. The air flaps may be opened for; Cooling - since the ovens do not have active cooling, if the temperature needs to be reduced the fan will stay at 100% and the air flap is opened to 100%. This allows maximum air exchange, so the temperature in the chamber falls. Venting - if you are using the oven for drying and are driving off a lot of water vapour, the air flap may be opened to let this moisture escape. NB this will simply allow the moisture out into the room, so bear this in mind. If there are fumes or vapours being given off during heating which cannot be vented into the room (e.g. harmful or corrosive vapours or gases that may reduce the oxygen content of the atmosphere) they should not be vented in this way. For harmful vapours and gases, fit a plug in tube extension to the ventilation port on the rear of the oven, and ensure the vapours are directed from this to a HVAC system or fume hood to avoid exposure.   For more information about Memmert ovens, choosing a suitable oven and customising it to suit your application, just follow the links above or contact us;