Automatic Tissue Processor with Thermostat

Quick Answer: The Automatic Tissue Processor with Thermostat is a histology instrument that takes fixed tissue through dehydrating, clearing and molten paraffin stages automatically, with a thermostat holding the heated stages at a set temperature. An automatic tissue processor with thermostat is used to prepare tissue for embedding and microtome sectioning.

Temperature Control in Paraffin Processing

Paraffin wax only infiltrates tissue while it is molten, and it should not be much hotter than it needs to be. Wax that cools sets in the tissue before infiltration is complete, while wax that is overheated hardens tissue and makes it brittle on the microtome. The thermostat on this processor holds the heated stages, normally the wax baths, at the temperature you set for the paraffin in use.

Before the wax, the instrument takes cassettes through fixative, a series of alcohols that remove water, and a clearing agent such as xylene that mixes with both alcohol and wax. Automating the transfers means the sequence can run unattended, commonly overnight. The listing names the thermostat rather than a programmable controller; for stored programmes, compare the microprocessor version. Station count and basket capacity are not stated.

Once processed, tissue is embedded in a wax block and sectioned, for example on the Rotary Microtome, Erma Type.

Care & Handling

• Check the thermostat setting of the automatic tissue processor with thermostat against a thermometer in the wax bath from time to time, and match it to the melting point printed on your paraffin.
• Stand the processor under extraction or in a ventilated room, since formalin and xylene vapours need controlling.
• Replace wax when it turns cloudy with carried-over clearing agent, and wipe spills before they set.
• Switch off and let the heated stages cool before cleaning around them.

Applications

• Processing tissue for paraffin sections in teaching histology laboratories
• Preparing animal organs for students to section and stain
• Routine overnight processing in smaller pathology and research labs

Specifications

Why Choose LabEquip

Colleges running histology practicals and smaller laboratories processing modest numbers of blocks tend to choose the thermostat model. It is listed in the LabEquip Microscope & Optics range; send your block numbers through the contact page.

Frequently Asked Questions

What does the thermostat control on a tissue processor?

It keeps the heated stages, normally the molten paraffin baths, at a set temperature. This keeps the wax liquid enough to infiltrate tissue without overheating it.

How does it differ from the microprocessor tissue processor?

The listing identifies this model by its thermostat, while the microprocessor model is identified by programmable control of step times. If you need several stored schedules or a delayed start, the microprocessor version is the one to compare.

Why does overheated wax cause problems?

Tissue held in wax that is too hot becomes hard and brittle, so sections crumble or crack on the microtome. Keeping the wax a few degrees above its melting point avoids this.

Can I use xylene substitutes?

Many laboratories use less hazardous clearing agents in place of xylene. Make sure the substitute suits the processor’s containers and seals and your paraffin, and allow for its different clearing time.

What happens to tissue after processing?

Cassettes go to an embedding station, where tissue is oriented in a mould of fresh wax to form a block. The cooled block is trimmed and sectioned on a microtome, and the sections are floated onto slides and stained.

How often should reagents be changed?

It depends on the number of cassettes run, but alcohols and clearing agent pick up water and fat over time. A regular rota, moving the least-used reagent up the sequence and adding fresh at the end, keeps dehydration reliable.

Last Updated: September 2026