A Solihull company is making waves in the marketplace - pilling up successful sales of an alternative to the traditional stopcock.
By opening the stopcock and lowering the level tube any desired quantity of the gas can be aspirated over.
Fasten the short length of wood to the Long piece using either screws or nails and your stopcock key is ready to use.
He then took a globe of copper fitted with pump and stopcock, and discovered that he could pump out air as well as water.
However, you also mention that it is difficult to fully close the stopcock.
It is then run back into the measuring tube by lowering the level tube, the stopcock is closed, and the volume noted.
One tube, called the "measuring tube," is provided with a capillary stopcock at the top and graduated downwards; the other tube, called the "level tube," is plain and open.
The "Regency portable fountain," patented in 1825 by Charles Plinth, was the prototype of the modern siphon, from which it differed in having a stopcock in place of a spring valve.
The clip is removed, the stopcock opened, and the level tube of the measuring apparatus raised, so that the gas passes into the first bulb.
The outside stopcock is very useful and you should familiarize yourself with it.
The test gas is brought to the stopcock, by means of a fine tube which has been previously filled with water or in which the air has been displaced by running the gas through.
They are responsible for their supply up to and including the water stopcock.
To use the apparatus, the measuring tube is completely filled with water by pouring water into both tubes, raising the level tube until water overflows at the stopcock, which is then turned.
Water is not a problem but any other obstruction will prevent you from locating the stopcock and so will need cleaning out.
Whilst the water is turned off, it would be more sensible to have a new stopcock fitted rather than repair the old one.