Memmert UN75 Universal Oven, space-saving heating and drying oven with natural convection, 74 litres, up to 300 °C

The Memmert UN75 universal oven has the same compact footprint as the smaller UN55, but is significantly taller, thereby offering 74 litres of internal volume and space for up to 6 trays instead of 4, without taking up any more floor space in the laboratory. Like all models in the UN series, it operates using purely natural convection within a temperature range of 20 to 300 °C. For laboratories with limited floor space but a growing sample load, the UN75 is therefore the obvious solution: greater throughput with the same footprint, rather than a larger, wider cabinet.

Natural convection even with six shelves

Even with up to six shelves, the Memmert UN75 universal oven does not require an air turbine or a forced-air fan. Heat rises purely by thermal convection; dust or light sample components are not stirred up by a fan. The operating temperature range starts at a minimum of 5 °C above room temperature and extends up to 300 °C. Those who run many batches on several levels simultaneously and require vibration-free conditions – for example, when handling loose powders or fibres – benefit from the additional number of shelves without sacrificing the advantages of natural convection. A Pt100 temperature sensor of DIN Class A in a 4-wire configuration provides a setting accuracy of 0.1 °C up to 99.9 °C and 0.5 °C from 100 °C.

ControlCOCKPIT SingleDISPLAY: a single operating interface for the entire series

Like the other UN models, the UN75 is operated via the ControlCOCKPIT SingleDISPLAY, an adaptive, multifunctional digital PID microprocessor controller with a TFT colour graphic display. Temperature can be set in Celsius or Fahrenheit, as can the position of the exhaust air damper, programme duration, time zone and summer/winter time. A digital countdown timer with target time can be set from 1 minute to 99 days; the SetpointWait function only starts the process time once the setpoint temperature has been reached. The data logger can be read via the Ethernet interface, and a time-limited trial version of the AtmoCONTROL software is available for download. Anyone wishing to use the same operating logic across several UN models will find it unchanged in the UN75.

Capacity and dimensions of the Memmert UN75 universal chamber

The interior measures 400 x 560 x 330 mm, whilst the external dimensions are 585 x 944 x 514 mm; with the same footprint as the UN55, it is therefore around 16 cm taller. Two electropolished stainless steel wire shelves are included as standard, and the cabinet can accommodate up to six inserts in total. The maximum load capacity is 120 kg for the entire unit and 20 kg per shelf. The interior consists of easy-to-clean stainless steel, reinforced with deep-drawn ribbing, featuring integrated, protected all-round heating on all four sides; the housing is made of textured stainless steel with a fully galvanised sheet steel rear panel. The UN75 is connected to 230 V (approx. 2,500 W) or 115 V (approx. 1,800 W), in each case at 50/60 Hz.

Selection guide: Footprint versus usable volume

Within the UN series with natural convection, the internal volume ranges from 32 to 749 litres. Two models share the same footprint and differ only in their overall height; it is worth taking a closer look at this when making your selection.

The UN55 and UN75 have the same footprint; the UN75 is simply taller and therefore offers two additional shelves. If there is no longer sufficient floor space in the laboratory, or if a significantly larger capacity is required, the Memmert UN110 universal cabinet, with a capacity of 108 litres and a larger footprint, is the next step up. For smaller sample quantities, the Memmert UN30 universal cabinet is often sufficient. The complete range of climate cabinets and incubators can be found under Climate Cabinets & Incubators.

Distinction: natural convection versus forced air circulation

If, instead of six shelves, you require particularly rapid and uniform heat distribution – for example, with tightly packed samples of varying sizes – you are better served by a forced-air model from the UF series. These units feature an electronically controlled fan and reach their operating temperature range from 10 °C rather than 5 °C above room temperature; in return, the heat is actively distributed throughout the interior. An example of a comparable size is the Memmert UF160 universal cabinet with a capacity of 161 litres. For samples sensitive to dust or air movement, such as powders laid out in the open, the natural convection of the UN75 remains the more suitable solution. Like all standard models in the UN series, the UN75 uses the ControlCOCKPIT SingleDISPLAY; the TwinDISPLAY configuration with two displays is reserved for the ‘plus’ variants of the series.

Safety in accordance with DIN 12880

The UN75 features adjustable electronic temperature monitoring and a mechanical temperature limiter of protection class 1 in accordance with DIN 12880, which switches off the heating when the temperature reaches approximately 20 °C above the maximum cabinet temperature – an important safeguard, particularly when several batches are running simultaneously overnight. A self-diagnostic system assists with fault-finding, and three freely selectable temperature values can be calibrated. The unit bears CE and EAC markings as well as a UL test mark.

Installation, operation and disposal

For operation, a minimum clearance of 15 cm from the wall and a maximum clearance of 20 cm from the ceiling must be maintained; a minimum of 5 cm clearance is sufficient on either side from the wall or an adjacent unit. Due to the unit’s considerable height of around 94 cm, it is advisable to check the available headroom at the intended installation site in advance. Installation is permitted at altitudes of up to 2,000 m above sea level, at an ambient temperature of 5 °C to 40 °C and a relative humidity of no more than 80 per cent, non-condensing. Electrically, the UN75 is designed for overvoltage category II and pollution degree 2; it must only be transported in an upright position. At the end of its service life, the UN75, as an electrical appliance, is subject to the Electrical and Electronic Equipment Act and must not be disposed of with household waste.

Typical applications

With an internal volume of 74 litres on a compact footprint and up to 6 shelves, the Memmert UN75 universal cabinet is ideal wherever multiple sample runs are carried out simultaneously but no additional floor space is available.

• Parallel drying of multiple sample batches in a confined space
• Vibration-free drying of dust- or air-sensitive materials
• Tempering, ageing and baking of material samples on multiple levels
• Material testing in industrial quality assurance
• A useful addition to laboratories wishing to upgrade from the UN30 or UN55 to greater capacity

Investment rationale: more levels instead of more floor space

The UN75 is supplied with 2 electropolished stainless steel grating trays as standard; the cabinet is designed to accommodate up to 6 trays. Customers wishing to utilise all six levels should order additional grating trays or perforated sheets accordingly. A full-view glass door is available for visual inspection without opening the door, along with interior lighting and a power socket for additional measurement equipment. Wall brackets or a stacking kit help to make even better use of the available floor space. For long-term data logging, an AtmoCONTROL software licence is recommended instead of the time-limited trial version; for applications subject to standards, calibration and IQ/OQ/PQ services are available, including those accredited by DAkkS.

Frequently asked questions before purchase

Why does the UN75 have more slots than the larger UN110?
The UN75 is significantly taller than the UN55 whilst occupying the same floor space, and therefore offers 6 slots instead of 5, even though the UN110 has a larger total volume of 108 litres and a larger footprint. The number of slots depends more on the height than on the volume alone.

Does the UN75 fit into the same space as a UN55?
Yes, the footprint is identical at 585 x 514 mm; at 944 mm high, the UN75 is only around 16 cm taller than the UN55, which is 784 mm high.

What is the total load capacity of the UN75?
Up to 120 kg distributed across a maximum of 6 shelves, with a maximum of 20 kg per shelf.

Is natural convection still sufficient with six levels?
For the vast majority of drying and tempering processes, yes. However, where there are very large temperature differences between the shelves or the load is very dense, a forced-air model such as the UF160 can operate more uniformly.

What is the accuracy of the temperature control?
As with the other models in the UN series, it is 0.1 °C up to 99.9 °C and 0.5 °C from 100 °C onwards, measured using a DIN Class A Pt100 sensor with 4-wire technology.

Is the UN75 suitable for unattended operation?
The mechanical temperature limiter, which complies with Protection Class 1 according to DIN 12880, switches off the heating in the event of an overtemperature of approximately 20 °C and is designed for night-time or weekend operation.

Technical details

Contents of delivery

• 1x Memmert UN75 universal cabinet
• Factory calibration certificate (calibration at 160 °C)
• Fully insulated stainless steel door with 2-point locking (compression door seal)
• 2x stainless steel grating, electropolished

Regulatory information

The Memmert UN75 universal cabinet is registered with the Stiftung Elektro-Altgeräte Register (Stiftung EAR) under WEEE registration number DE 66812464.

Customised requirements & procurement service

Options available for the UN75 include fully transparent glass doors, interior lighting and a power socket, reinforced grating and perforated sheets, slide-in or floor-standing drip trays, as well as wall brackets, levelling feet and a stacking kit. A USB-to-Ethernet adapter and AtmoCONTROL software licences are available for data acquisition. In addition, we arrange calibration, IQ/OQ/PQ and maintenance services, some of which are DAkkS-accredited. Do you require any of these accessories or assistance in selecting the right universal cabinet for your application? Through our procurement service, LT Laborhandel will be happy to assist you with procurement and configuration.