Memmert UN75pa paraffin cabinet, virtually gas-tight heating cabinet for pathology, 74 litres, +20 to +80 °C, TwinDISPLAY

The Memmert UN75pa paraffin cabinet is not a universal oven, but a dedicated unit for sample preparation in pathology: 74 litres’ internal volume, a temperature range limited to +20 to +80 °C, and an internal chamber that is virtually gas-tight as standard, which retains paraffin vapours within the unit. Unlike the UN75, the UN75pa comes as standard with TwinDISPLAY, featuring two redundant Pt100 sensors, HeatBALANCE and AutoSAFETY. The unit operates using natural convection and has no air turbine. For sections being prepared for microscopy, this ensures reliably constant temperatures without any air movement inside the chamber.

Restricted temperature range for paraffin applications

The temperature range of the UN75pa is 20 to 80 °C, which is considerably narrower than that of the UN75 (20 to 300 °C), as the paraffin embedding does not require higher temperatures. The working temperature range starts at a minimum of 5 °C above room temperature, the same as for all Memmert units with natural convection. Two DIN Class A Pt100 sensors in a 4-wire configuration monitor each other and provide a setting accuracy of 0.1 °C across the entire range. As no air turbine is fitted, the heat rises purely by convection, without a fan stirring up dust or circulating paraffin vapours inside the chamber.

A virtually gas-tight interior: standard rather than optional

Whilst a gas-tight interior is only available as an optional extra (K2/K3) on the UN75, it comes as standard on the UN75pa. This retains paraffin vapours in the interior instead of letting them escape into the laboratory, an important aspect of health and safety in pathology. Combined with the ControlCOCKPIT TwinDISPLAY control system, which is fitted as standard, the UN75pa offers HeatBALANCE for fine-tuning the distribution of heating power, as well as AutoSAFETY for additional over- and under-temperature monitoring with visual and audible alarms.

Capacity and dimensions of the Memmert UN75pa paraffin cabinet

The internal dimensions are 400 x 560 x 330 mm; the external dimensions of the housing are 585 x 944 x 514 mm, and the net weight is approximately 66 kg, with the same footprint as the UN75 and UF75. 2 electropolished stainless steel grid shelves are included as standard; up to six shelves can be fitted in total. The maximum total load is 120 kg, with a maximum of 20 kg per shelf. The interior consists of easy-to-clean, deep-drawn ribbed, virtually gas-tight stainless steel with protected, integrated 4-sided all-round heating; the housing is made of textured stainless steel with a fully galvanised sheet steel rear panel. The UN75pa can be connected either to 230 V (approx. 1,250 W) or to 115 V (approx. 900 W), in both cases at 50/60 Hz; this results in significantly lower power consumption than the forced air circulation models in the series, as the temperature only needs to be raised to 80 °C rather than 300 °C.

Distinction: Paraffin cabinet versus universal oven UN75/UF75

The UN75pa is not a universal oven and should not be regarded as such. Anyone looking for a natural convection oven with a full temperature range up to 300 °C for general laboratory drying is in the right place with the Memmert universal oven UN75. If, on the other hand, you need active air circulation for shorter heating times, you’ll find this in the Memmert universal oven UF75. For paraffin embedding in other sizes, Memmert also offers the Memmert UN30pa paraffin cabinet (32 litres), the Memmert UN110pa paraffin cabinet (108 litres) and the Memmert UN160pa paraffin cabinet (161 litres), each with the same limited temperature range and gas-tight interior as the UN75pa described here.

Safety according to DIN 12880, enhanced by AutoSAFETY

In addition to the adjustable electronic temperature monitoring and AutoSAFETY, the UN75pa is fitted with a mechanical temperature limiter of protection class 1 according to DIN 12880, which switches off the heating when the temperature reaches approximately 20 °C above the maximum cabinet temperature, in the case of this model, this occurs at around 100 °C. The display also allows you to select either an adjustable temperature monitor of protection class 3.1 or an adjustable temperature limiter of protection class 2. An integrated 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 distance of 15 cm from the wall and a minimum distance of 20 cm from the ceiling must be maintained; a minimum of 5 cm is sufficient on either side in relation to the wall or an adjacent unit. The unit may be installed 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 %, non-condensing. Electrically, the UN75pa is designed for overvoltage category II and pollution degree 2; it must only be transported in an upright position. The virtually gas-tight interior, made of easy-to-clean stainless steel, can be cleaned using standard laboratory cleaning agents; paraffin residues should be removed regularly to prevent the seals of the gas-tight interior from sticking together. As an electrical appliance, the UN75pa is subject to the Electrical and Electronic Equipment Act at the end of its service life and must not be disposed of with household waste; see Regulatory information below.

Typical applications

With a limited temperature range and a virtually gas-tight interior, the Memmert UN75pa paraffin cabinet is specifically designed for sample preparation using paraffin.

• Preparation of microscopic slides in pathology
• Paraffin embedding of tissue samples for histological examination
• Paraffin-based sample preparation in science and research
• Training and apprenticeships, for example in clinical pathology or histology

Investment rationale: Equipment tailored to the specific purpose

The scope of delivery for the UN75pa includes 2 electropolished stainless steel grid shelves; the cabinet is designed to accommodate up to 6 shelves, whilst TwinDISPLAY and the gas-tight interior are already included in the base price, rather than being available as optional extras as with the Memmert universal oven UN75. A full-view glass door is available as an option for visual inspection without opening the door, as are a lockable door, a reversible door hinge and a potential-free alarm contact for connection to a building management system. A USB-to-Ethernet adapter and AtmoCONTROL software licences are available for continuous logging. Anyone requiring a different size for paraffin embedding will find it in the Memmert UN30pa paraffin cabinet, Memmert UN110pa paraffin cabinet or Memmert UN160pa paraffin cabinet. For pharmaceutical or standards-governed applications, we provide calibration, IQ/OQ/PQ and maintenance services, including DAkkS calibration on request.

Frequently asked questions before making a purchase

Why is the temperature range limited to 80 °C?
Paraffin embedding in pathology does not require higher temperatures; the UN75pa is specifically designed for this application and is therefore not a substitute for a universal oven.

Why does a natural convection unit have TwinDISPLAY?
TwinDISPLAY with HeatBALANCE and AutoSAFETY comes as standard on the UN75pa, even though the unit operates without an air turbine.

Is the gas-tight interior really completely gas-tight?
According to the technical data sheet, the interior is virtually gas-tight, not completely hermetic; this is a specific standard feature of the paraffin cabinet, unlike the UN75, where the same design is only available as an option.

How many samples can fit into the UN75pa at any one time?
Two grid shelves are included as standard; up to six shelves, each with a maximum load of 20 kg, are possible, giving a total load capacity of up to 120 kg.

Can I also use the UN75pa for standard laboratory drying?
Technically, yes, up to 80 °C; however, for the full temperature range up to 300 °C, the Memmert universal oven UN75 or the Memmert universal oven UF75 is the right choice.

What other sizes are available for paraffin cabinets?
Memmert also offers the Memmert paraffin cabinet UN30pa (32 litres), the Memmert paraffin cabinet UN110pa (108 litres) and the Memmert paraffin cabinet UN160pa (161 litres), each operating on the same principle.

Is the UN75pa suitable for continuous operation?
The mechanical temperature limiter, which complies with Protection Class 1 as per DIN 12880, in combination with AutoSAFETY, switches off the heater in the event of an overtemperature of approximately 20 °C and is designed for unattended operation.

Does the UN75pa actively circulate fresh air?
No, the UN75pa operates using natural convection without an air turbine or recirculation fan; the heat rises purely by thermal action, which prevents paraffin vapours from swirling around inside the unit.

Technical details

Scope of delivery

• 1x Memmert paraffin cabinet UN75pa
• Factory calibration certificate (calibration at 80 °C)
• Fully insulated stainless steel door with a 2-point locking system (compression door lock)
• 2x stainless steel grid shelf, electropolished
• Virtually gas-tight interior (standard fitment, not an accessory)

Regulatory information

The Memmert UN75pa paraffin cabinet is registered with the Stiftung Elektro-Altgeräte Register (Stiftung EAR) under WEEE registration number DE 66812464.

Individual requirements and procurement service

Accessories available for the UN75pa include, amongst others, a full-view glass door, a lockable door, a reversible door hinge, a wall bracket, a stacking kit and levelling feet. A USB-to-Ethernet adapter and AtmoCONTROL software licences are available for data logging. In addition, we arrange calibration, IQ/OQ/PQ and maintenance services, including DAkkS calibration on request. Do you require a different size of paraffin cabinet or assistance in selecting the right unit for your pathology practice? Through our procurement service, we are happy to assist you with procurement and configuration.