Crucible Sleeve, Set

Quick Answer: The Crucible Sleeve, Set is a group of flexible rubber sleeves in different sizes that hold a filter crucible airtight in a funnel or crucible holder. A crucible sleeve set lets a Gooch or sintered glass crucible be used for suction filtration on a filtering flask.

Sealing a Crucible Into a Suction Line

In gravimetric analysis a precipitate is often collected in a filter crucible, weighed with the crucible, and the mass of product found by difference. The crucible has no stem of its own, so it needs an adapter to sit on a filtering flask. A rubber sleeve does that job: it is fitted into a funnel or holder, the crucible is pushed into the sleeve, and when suction is applied the rubber is pulled tight around the crucible wall so that all air and liquid must pass through the filter bed.

Because crucibles come in several diameters and tapers, sleeves are supplied as a set so that the closest fit can be chosen. A low form Gooch crucible with sintered disc is a typical partner, and the same principle applies to porcelain Gooch crucibles packed with a filter mat. Rubber cones that seal a funnel directly into a flask neck do a related but different job and are listed separately as filtration rubber cones.

The exact form of the sleeves in this set, and the crucible sizes they suit, should be checked against your crucibles before ordering.

Specifications

Applications

• Gravimetric determination of sulfate as barium sulfate or chloride as silver chloride
• Filtering and washing precipitates that are then dried and weighed in the crucible
• Collecting fine solids on sintered crucibles in college analytical practicals
• Filtering crystals that must be dried in the same vessel they were collected in

Care & Handling

• Moisten the sleeve slightly so the crucible slides in without tearing the rubber.
• Release the vacuum before pulling the crucible out, otherwise the sleeve can tear or the filter bed can be disturbed.
• Rinse sleeves in distilled water after use so salt residues do not dry into the rubber.
• Keep sleeves out of drying ovens and muffle furnaces; only the crucible goes in.

Why Choose LabEquip

Crucible sleeves are ordered mainly by colleges, analytical teaching labs and quality-control rooms that run gravimetric methods. LabEquip lists this set under General Lab Products; send the crucible sizes you use via the contact page.

Frequently Asked Questions

What is a crucible sleeve used for?

It forms an airtight seal between a filter crucible and the funnel or holder it sits in, so that suction draws liquid through the crucible’s filter rather than around its sides.

Which crucibles fit these sleeves?

They are intended for filter crucibles such as Gooch and sintered glass types. The set contains several sizes so that the sleeve which grips your crucible most closely can be chosen.

Why is my filtration slow even with the sleeve fitted?

If the seal is good, a slow rate usually means a clogged filter: very fine precipitate, a sinter of too fine a porosity, or a filter mat packed too tightly. Digesting the precipitate in warm mother liquor to grow larger particles often helps.

Can the sleeves go into the oven with the crucible?

No. Remove the crucible from the sleeve before drying or igniting it. Rubber would soften or burn, and any residue would add to the weighed mass.

How is a crucible sleeve different from a filter cone?

A filter cone seals the stem of a Buchner or Hirsch funnel into the neck of a filtering flask. A crucible sleeve seals the stemless crucible itself into a funnel or holder above the flask.

How do I avoid tearing the sleeve?

Wet the rubber, push the crucible in with a slight twist, and always release the vacuum before removing it. Store the sleeves flat and clean so they do not harden.

Last Updated: September 2026