Interchangeable Laboratory Glassware

This section covers the comprehensive range of interchangeable jointed ware for every day laboratory work, which can be used efficiently for inter-connecting laboratory apparatus.

The range of interchangeable glassware is large and provides many products with standard ground sockets such as boiling flasks and Erlenmeyer flasks with a host of jointed tubular items, condensers and dropping funnels. The versatility of these joints enables any system to be easily and rapidly assembled and in operation provide an efficient, reliable connection which can be confidently used under a wide range of laboratory operating conditions.

All apparatus with interchangeable joints are manufactured from finest quality borosilicate glass which gives maximum resistance to thermal and mechanical stress and chemical attack.

In order to help the reader to locate the data he requires, we have divided the contents into sections as mentioned below which broadly classify the components according to their most common applications.

-          Adapters

-          Bottles

-          Condensers

-          Columns

-          Flasks

-          Funnels

-          Reactors

-          Stirrers

-          Stopcocks

-          Stoppers

-          Tubes

-          Assemblies

In a laboratory a condenser is a piece of laboratory glassware used to cool hot vapors or liquids. A condenser usually consists of a large glass tube containing a smaller glass tube running its entire length, within which the hot fluids pass. The ends of the inner glass tube are usually fitted with ground glass joints which are easily fitted with other glassware. During reflux, the upper end is usually left open to the atmosphere or vented through a bubbler or a drying tube to prevent the ingress of water or oxygen.

The outer glass tube usually has two hose connections, and a coolant (usually tap water or chilled water/anti-freeze mixture) is passed through it. For maximum efficiency, and to maintain a smooth and correctly directed thermal gradient so as to minimize the risk of thermal shock to adjacent glassware, the coolant usually enters through the lower fitting, and exits through the higher fitting. Maintaining a correct thermal gradient (i.e. entering coolant at the cooler point) is the critical factor. Multiple condensers may be connected in series. Normally a high flow rate is not necessary to maintain a cooling surface.

Condensers are often used in reflux, where the hot solvent vapors of a liquid being heated are cooled and allowed to drip back. This reduces the loss of solvent allowing the mixture to be heated for extended periods.  Condensers are used in distillation to cool the hot vapors, condensing them into liquid for separate collection. For fractional distillation, an air or Vigreux condenser is usually used to slow the rate at which the hot vapors rise, giving a better separation between the different components in the distillate.

In a laboratory a flask is a piece of laboratory glassware used for making solutions or for holding, containing, collecting or sometimes volumetrically measuring chemicals, samples, solutions, etc.   for chemical reactions or other processes such as mixing, heating, cooling, dissolving, precipitation, boiling (as in distillation), or analysis.

In laboratory and other scientific settings, they are usually referred to simply as flasks. Flasks come in a number of shapes and a wide range of sizes, but a common distinguishing aspect in their shapes is a wider vessel "body" and one (or sometimes more) narrower tubular sections at the top called necks which have an opening at the top. Laboratory flask sizes are specified by the volume they can hold, typically in metric units such as milliliters or liters .

At the opening(s) at top of the neck of some glass flasks such as round-bottom flasks or sometimes volumetric flasks, there are outer (or female) tapered (conical) ground glass joints. Some flasks, especially volumetric flasks, come with a stopper or cap for capping the opening at the top of the neck. Reaction flasks, which are usually spherical (i.e. round-bottom flask) and are accompanied by their necks, at the ends of which are ground glass joints to quickly and tightly connected to the rest of the apparatus (such as a reflux condenser or dropping funnel). The reaction flask is usually made of thick glass and they can tolerate large pressure differences, with the result that you can keep two both in a reaction under vacuum, and pressure, sometimes simultaneously.

In a laboratory a funnel is a piece of laboratory glassware used for transferring fluids. There are many different kinds of funnels that have been adapted for these specialized applications. Filter funnels, thistle funnels, separating funnels and dropping funnels which allow the fluids to be added to a flask slowly. For solids, a powder funnel with a wide and short stem is more appropriate as it does not clog easily.

Separating Funnels & Dropping Funnels are fitted with a stopcock which allows the flow of to be controlled. Dropping funnels are useful for adding reagents slowly, i.e. drop-wise. This may be desirable when the quick addition of the reagent may result in side reactions, or if the reaction is too vigorous.

Pressure-equalizing dropping funnels have an additional narrow-bore glass tube from the bulb of the funnel, to the ground glass joint around the stem. Without means to equalize the pressure between a sealed receiving flask and the bulb of the funnel, the flow of fluid will rapidly come to a halt.