Description
Expansion adapter KNS 12/21 to HNS 14/23 is a compact ground-joint transition piece that steps a smaller cone joint up to the next common socket size in laboratory glassware. It comprises a cone (Kern) NS 12/21 and a socket (Hülse) NS 14/23, produced in accordance with DIN 12257 for full interchangeability within standard Normschliff assemblies.
This article is part of Hose connectors, adapters & fittings, in Tubing, hoses & fittings.
Supplied as a single piece weighing 0,012 kg net, this lightweight expansion adapter is intended for fine-scale apparatus where a modest increase in joint diameter is required. Typical applications include small distillation bridges, micro-reaction setups and analytical glass trains that combine NS 12/21 and NS 14/23 components. The adapter is manufactured by Witeg and originates from Baden-Württemberg, Germany.
Its short, precise geometry supports stable alignment and reliable sealing when connecting instruments or flasks of neighbouring joint sizes. Research and teaching laboratories that standardise on DIN taper joints can use this piece to extend existing glassware without custom fabrication, maintaining vacuum integrity and mechanical fit across the transition.
Key features
- Pack size: 1 pc
- Cone joint: NS 12/21
- Socket joint: NS 14/23
- Standard: DIN 12257
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Questions about Expansions adapter ST 12/21 -> ST 14/23
What is this article?
Expansions adapter ST 12/21 -> ST 14/23 is the article on this page. Luminix Health distributes Witeg for laboratory use. It sits in Hose connectors, adapters & fittings, inside Tubing, hoses & fittings, in Labware.
A hose connector or adapter joins two lines, or steps one bore down to another. The barb diameter has to match the tube, and the thread has to match the stopcock or the bottle. Most leaks are a mismatch here, not a hole in the tube.
Tubing is how a liquid or a gas moves between two vessels without being poured. Silicone stays flexible and survives repeated autoclaving. PTFE resists almost every solvent and is stiff. PVC is the ordinary flexible line for water and for mild aqueous work. The fitting, not the tube, is what usually leaks: the barb, the thread and the stopcock have to match the tube bore. Glass and plastic apparatus around these lines is indexed under ISO laboratory ware.
Which category should I open next?
The category is Tubing, hoses & fittings. The sub-category is Hose connectors, adapters & fittings. The catalogue is Labware.
Shelves beside this one are PVC, PTFE & other tubing, Stopcocks & valves, Silicone tubing and Tubing accessories.
What should I check before I order?
When this page shows a safety data sheet, use that manufacturer file. Hazard text does not belong in the sales description. For a pack size, a grade or a certificate that is not on the page, send a quote request or contact the team.
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Luminix Health distributes this article from the heart of Europe. Articles in stock ship within 2–5 business days. Standard delivery is free from €250 excl. VAT. Cold-chain goods and dangerous goods under ADR are never included in that free delivery. The terms are in the Shipping Policy. The full brand index is on shop by brand. Who we are is on about us.
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The seven catalogues are Labware, Lab chemicals, Lab instruments, Lab consumables, Chromatography equipment, Lab safety equipment and Life Science & Microbiology.