Bloquer la chaleur

Quick Answer: Bloquer la Chaleur is a heating block for round-bottom flasks that sits on a hotplate stirrer and holds the flask in a deep metal well. The French name on the listing is a garbled translation of “bloc chauffant”, which simply means heating block.

About the Name and the Block

Read literally, “bloquer la chaleur” means “block the heat” in French, which is the opposite of what the item does. It appears to be an automatic translation of “bloc chauffant”, the usual French term for a heating block. The page therefore describes the item by its function. The listing photograph shows a dark grey, matt-finished block with a broad circular foot and a tall collar around a deep, straight-sided well.

A deep, straight-sided well is a clue to how blocks of this shape are commonly used: a round-bottom flask sits low in the well, or the well accepts a separate insert shaped for a particular flask size. The listing does not say whether inserts are included or which flask sizes the block serves, so that is the one detail to settle before ordering.

Like other dry heating blocks, this one sits on the flat top of a hotplate or hotplate magnetic stirrer, and heat moves by conduction from the top plate into the flask. The tall collar surrounds more of the flask wall than a shallow adapter would, which helps keep the flask contents at an even temperature during long reactions.

Practical Uses

• Heating reaction flasks under reflux without an oil bath
• Keeping a flask warm and stirred during a slow addition from a dropping funnel
• Solvent removal or concentration from a round-bottom flask at a controlled temperature
• Demonstrating dry-block heating as a safer option than open oil baths in a teaching lab

Specifications

Care and Safe Use

• Stand the block on a hotplate whose top plate is at least as wide as the block’s foot
• Clamp the flask neck and any condenser to a support rod before heating
• Remember that a dark matt finish gives no visual clue of temperature; allow a long cool-down
• Clean the well with a soft cloth only after cooling, and keep inserts, if used, dry and free of residue

Why Choose LabEquip

This block is usually requested by chemistry labs that already run heating magnetic stirrers and want flask heating without the mess of an oil bath. LabEquip can confirm which flask sizes the well serves and quote the block with clamps and a support rod from the general lab products range; contact us with your flask sizes.

Frequently Asked Questions

What does Bloquer la chaleur mean?

Literally it means block the heat in French. On this listing it is a mistranslation of bloc chauffant, the French term for a heating block, so the item is a heating block for flasks.

Does the block heat the flask by itself?

No. It has no heater of its own. It sits on a hotplate or hotplate stirrer and passes the heat from the top plate to the flask by conduction.

Why does the well look deeper than on other flask adapters?

A deep, straight well surrounds more of the flask and often takes a separate insert shaped for one flask size. Ask us whether inserts are included and which flask sizes they suit when you enquire.

Is a heating block safer than an oil bath?

In several ways, yes. There is no hot oil to spill or catch fire and no oil vapour. The block still reaches high temperatures, so gloves, clamping and careful placement remain necessary.

Can I use the block for low-boiling solvents?

Yes, provided the hotplate is set well below the level that would cause bumping, a stir bar or boiling chips are used, and a condenser is fitted for reflux work.

Why does my flask heat more slowly in the block than I expected?

Heat only passes where glass touches metal. If the flask sits loosely, or the well is dirty, transfer drops. A correctly sized insert and a clean contact surface usually fix this.

Last Updated: September 2026