Bell Jars

Bell jars are glass containers which are shaped like a bell. Although they are predominately made from glass, they can also be manufactured in metal such as stainless steel. This type consists of base plates, base wells and feed-through collars; it also needs a viewing window as it is not transparent. Bell jars can be used to create and contain a low-quality vacuum. The jar is placed on the base and vented to a hose fitting which is connected to a vacuum pump. The lower edge forms a flange of heavy glass and its bottom is smooth for better contact. The vacuum creates a compression force so there is no need for a seal. This can only be used in applications below atmospheric pressure. The second use of a bell jar is for preservation. This is constructed of much thinner glass and as the base flange is delicate, it is not suitable for creating a vacuum. Instead, it can be used as a basic form of protection for fragile objects or specimens. Bell jars are mainly used in educational facilities to create a low-cost vacuum for experiments. In professional laboratories, they may be used for preservation but a more efficient vacuum chamber is used instead of a bell jar.

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  • Elite Thermal Systems Ltd

  • Lab Unlimited UK