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Test Equipment - Volume and dimension measuring stand


This test stand is designed to accurately measure the change in volume and dimensions of a pressure vessel at different pressures.

The test stand consists of a solid base that the bottle stands on with a back support for the air inlet hose, and scale measurement.

Test stand with bottle full of water standing on the base.

Measuring change in length

A nozzle adaptor is fitted to the top of the bottle to allow an air supply to be connected. Attached to the nozzle adapter is a needle that extends out to one side. the needle is adjusted to point at the scale attached to the stand.

As the bottle is pressurised the top of the bottle stretches vertically and a reading can be taken from the needle.

Measuring change in circumference

A strip of paper with a printed scale is attached at one end with tape to the bottle. The other end of the strip is wrapped once around the bottle.

The end of the strip is attached to a hanging weight via a thread. This hanging weight provides necessary tension on the strip as the bottle expands. The end of the paper strip is reinforced with a piece of clear tape.

A mark is placed on the inner part of the strip section so that the scale can be read in relation to it.

As the bottle is pressurised the circumference will increase and the position of the mark relative to the scale will move. The difference between the two readings is the amount of circumference change under pressure.

Measuring change in volume

The bottle is completely filled with water all the way up to the neck. A zero mark is made at the bottom of the meniscus. The bottle is then pressurised to the desired level. The water level drops in proportion to the pressure applied. A mark is then made for the new meniscus level. The volume above the water level is volume increase as a result of the bottle stretching.

When the bottle is depressurised enough water is emptied until the meniscus lines up with the pressurised mark. The bottled is placed on a scale and weighed. Water is then added to the bottle until it reaches the unpressurised mark and the bottle is weighed again.

The difference in weight in grams represents the volume increase in mL.



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