Hollowed glass stoppers

Secure Sealing Solutions with Hollowed Glass Stoppers

When you're running reactions that need atmospheric control but still require access for probes or gas exchange, standard solid stoppers just won't cut it. Hollowed glass stoppers solve this problem by combining leak-proof sealing with internal accessibility—you get the secure closure your experiment demands without sacrificing functionality.

Manufactured from borosilicate glass 3.3, these stoppers handle everything from cryogenic temperatures down to -80°C up to extreme heat at +500°C. The precision-ground joints create reliable seals while the hollow center accommodates thermometers, stirring rods, gas inlet tubes, or sampling probes without compromising your closed system.

Ventilation Design Features for Pressure Control

The hollow construction isn't just about tool insertion—it's engineered for controlled gas exchange and pressure equalization. When you're working with vacuum distillation setups or fermentation monitoring, pressure differentials can crack glassware or blow seals. The central channel allows gradual pressure normalization while maintaining isolation from external contaminants.

Compare this to using a Separatory Funnel with a PTFE screw stopcock for liquid-liquid extractions—both require precise pressure management, but hollowed stoppers give you that control in sealed reaction vessels. For gas chromatography sample prep, you can purge headspace through the hollow center while keeping your sample isolated. The design works particularly well with Buchner Flask setups when you need vacuum filtration with simultaneous gas monitoring.

Material Composition and Chemical Resistance

Borosilicate glass 3.3 construction means these stoppers resist attack from:

• Strong acids and bases across the pH spectrum
• Organic solvents including chlorinated compounds
• Oxidizing agents used in analytical procedures
• Thermal shock during rapid temperature changes

Maximum working pressure reaches 1.5 bar, sufficient for most laboratory applications. The chemical inertness matters when you're running overnight reactions—no leachables contaminating your results, no degradation affecting seal integrity.

Compatible Glassware and Size Selection

Available in standard taper sizes from 10/30 through 45/50, manufactured to DIN/ISO specifications. Match these with your existing round-bottom flasks, distillation columns, or reaction vessels. The ground glass joints mate perfectly with Funnels and specialized equipment like the Funnel Separatory pear shape ISO4800 when you're scaling up separations.

Sizing tip: Measure your glassware's joint size before ordering—a 24/40 stopper won't seal a 29/42 opening. For pharmaceutical research and quality control work, keep multiple sizes in stock since different procedures require different vessel volumes. Autoclavable and solvent-washable, these stoppers maintain dimensional accuracy through hundreds of use cycles.