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 general-purpose cabinet, but a dedicated unit for specimen preparation in pathology: it has an internal volume of 74 litres, a temperature range limited to +20 to +80 °C, and an interior that is virtually gas-tight as standard, which retains paraffin vapours within the unit. Unlike the structurally identical UN75, the UN75pa comes as standard with TwinDISPLAY, featuring two redundant Pt100 sensors, HeatBALANCE and AutoSAFETY, even though 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 extends from 20 to 80 °C, which is significantly narrower than that of the UN75 (20 to 300 °C), as paraffin embedding does not require higher temperatures. The operating temperature range starts at a minimum of 5 °C above room temperature – the same formula 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 control accuracy of 0.1 °C across the entire range. As there is no air turbine fitted, heat rises purely by convection, without a fan stirring up dust or circulating paraffin vapours inside the chamber.

Virtually gas-tight interior: standard rather than an option

Whilst a gas-tight interior is only available as an optional extra (K2/K3) at an additional cost on the UN75, it comes as standard on the UN75pa. This keeps paraffin vapours contained within the interior rather than allowing them to 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 despite the use of natural convection, 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. The data sheet does not explicitly state why Memmert has opted for TwinDISPLAY rather than SingleDISPLAY in this model, even though the unit operates using natural convection; however, the increased safety requirements when working with paraffin vapours are an obvious reason.

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; the net weight is approximately 66 kg; and it has the same footprint as the UN75 and UF75. Two electropolished stainless steel wire shelves are included as standard; a total of up to six shelves can be fitted. The maximum total load is 120 kg, with up to 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 115 V (approx. 900 W), in both cases at 50/60 Hz; this represents significantly lower power consumption than the forced-air models in the series, as the temperature only needs to be raised to 80 °C rather than 300 °C.

Distinction: Paraffin cabinet versus UN75/UF75 universal cabinet

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 will find the Memmert UN75 universal oven suitable. Those who, instead, require active air circulation for shorter heating times will find this in the Memmert UF75 universal oven. 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 featuring the same limited temperature range and gas-tight interior as the UN75pa described here.

Safety in accordance with DIN 12880, enhanced by AutoSAFETY

In addition to the adjustable electronic temperature monitoring and AutoSAFETY, the UN75pa features a mechanical temperature limiter of protection class 1 in accordance with DIN 12880, which switches off the heating at approximately 20 °C above the maximum cabinet temperature – in the case of this model, therefore, at around 100 °C. The display also allows you to select either a temperature selector monitor of protection class 3.1 or a temperature selector 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 mark.

Installation, operation and disposal

For operation, a minimum distance of 15 cm from the wall and a maximum distance of 20 cm from the ceiling must be maintained; a minimum of 5 cm is sufficient on the sides relative to the wall or an adjacent unit. 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 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 its limited temperature range and 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
• Sample preparation using paraffin in science and research
• Training and education, for example in practical training in pathology or histology

Reason for investment: Equipment tailored to the specific purpose

The UN75pa is supplied with 2 electropolished stainless steel wire shelves; the cabinet is designed to accommodate up to 6 inserts, whilst the TwinDISPLAY and the gas-tight interior are already included in the base price, rather than being available as optional extras as with the Memmert UN75 universal cabinet. 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 data logging. If you require a different size for paraffin embedding, you will find it in the Memmert UN30pa paraffin cabinet, the Memmert UN110pa paraffin cabinet or the Memmert UN160pa paraffin cabinet. For pharmaceutical or standards-compliant applications, we arrange calibration, IQ/OQ/PQ and maintenance services, including those accredited by DAkkS.

Frequently asked questions before purchase

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

Why does a natural convection unit have TwinDISPLAY?
The data sheet does not explicitly explain this; TwinDISPLAY with HeatBALANCE and AutoSAFETY comes as standard on the UN75pa, even though the unit operates without a fan, presumably due to the increased safety requirements when working with paraffin vapours.

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

How many samples can fit into the UN75pa at the same time?
Two wire shelves are included as standard; up to 6 trays, 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 UN75 universal cabinet or the Memmert UF75 universal cabinet is the more suitable choice.

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

Is the UN75pa suitable for continuous operation?
The mechanical temperature limiter, protection class 1 in accordance with DIN 12880, in combination with AutoSAFETY, switches off the heating element in the event of an overtemperature of approximately 20 °C and is designed for unattended operation.

Is fresh air actively circulated in the UN75pa?
No, the UN75pa operates using natural convection without an air turbine or recirculation fan; the heat rises purely by thermal action, which prevents the swirling of paraffin vapours inside the room.

Technical details

Contents

• 1x Memmert UN75pa paraffin cabinet
• Factory calibration certificate (calibration at 80 °C)
• Fully insulated stainless steel door with 2-point locking (compression door seal)
• 2x stainless steel grating, 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.

Customised requirements & procurement service

Options available for the UN75pa include a fully glazed door, a lockable door, a reversible door hinge, a wall bracket, a stacking kit and levelling feet. A USB-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 a different size of paraffin cabinet or assistance in selecting the right unit for your pathology practice? Through our procurement service, LT Laborhandel will be happy to assist you with procurement and configuration.