Rion VM-230A Acoustical Capacity Meter

SKU: VM-230A

Overview

The Rion VM-230A is a non-invasive instrument that measures capacity of objects using acoustic detection. This instrument can rapidly measure the capacity of a combustion chamber without the use of liquids like in the traditional Archimedes or Burette based methods.

Applications

The automotive industry is the primary market for this instrument, as it is used regularly to measure the volume of a combustion chambers in cylinder heads.

Features

Dry, non-contact method: No immersion in liquid is required, making it ideal for the measurement of cylinder heads by placing the meter on top of the combustion chamber cavity.
Measurements are completed in around 2 seconds.
Accuracy of measurement is within ±0.05 cm³ when measuring roughly 50 cm³ under standard conditions (20 °C, 50% RH)
Attachments can be used to measure spark plug cavities as well.

Measurement Principle

The VM230A’s reference loudspeaker will generate a sine signal inside a sound source chamber.
This method works by taking measurements in two chambers—
- V₁: Sound source chamber with known volume.
- V₂: Combined volume of the attachment space plus the unknown object volume (V₂ =Vx + V₀).
Calibration via capacity reference containers (three) refines accuracy; for a 50 cm³ object, precision can reach ±0.05 cm³.
The system measures tiny changes in pressure (ΔP₁ in the known chamber and ΔP₂ in the test space) due to sound propagation.
The ratio of these pressure changes is proportional to the volume—allowing calculation of V₂, and thus the target object’s actual volume.
Beware of acoustic leakage. Even a small amount of dust can create a gap between the measuring chamber attachment and the measurement target which can render results unreliable.

Downloads

VM-230 and VM-240 Datasheet

Measuring the Capacity of an Engine Combustion Chamber Using Sound

Rion VM-230A Acoustical Capacity Meter

SKU: VM-230A

The Rion VM-230A is a non-invasive instrument that measures the capacity of objects using acoustic detection.