Volume meters are devices that measure the volume of a substance, typically a fluid or a gas, passing through a set point in a circuit or system. These meters do not measure flow rates or pressure but rather the total amount of material passing through them. Volume meters are commonly used to measure consumer consumption for billing purposes or as process metering devices in production facilities. Typical gas volume meters include diaphragm, rotary and turbine meters, and fluid volume meters include compound meters, turbine and multi-jet types. Both gas and fluid meters display measurements on an integral readout.
The accurate measurement of process or consumer usage of gas and fluid products requires a device capable of measuring total material volumes. This type of volume meter measures the total amount of material flowing through rather than the flow rates or internal system pressure. Generally located at fluid or gas entry points, volume meters are used to update monthly billing details for consumers or to establish system performance in manufacturing installations. The most common volume meter types feature an integral readout, typically a combination of rotary dial and odometer-type indication or a digital readout.
Both fluid and gas volume meters feature several distinct types of measurement mechanisms. Turbine-type meters are common to both applications and consist of a small internal propeller that is turned by the fluid or gas passing through the meter. The rotary motion is transferred to an electronic or mechanical counter that advances the readout. In both cases turbine meters are not suitable for systems with high flow rates.
Other common gas volume meter types include orifice and diaphragm meters. Orifice meters are differential types and rely on a machined internal orifice with a pressure sensor on either side. As gas passes through the orifice, a flow disturbance is created with a resultant pressure differential. The meter uses the different pressure readings between the two sensors to calculate the total volume of gas passing through the meter. Diaphragm meters utilize the continuous flexing of two or more diaphragms in the gas flow path to advance the readout.
Water volume meters generally fall into two categories: displacement and velocity meters. A displacement volume meter is very accurate at low flow rates and includes oscillating piston and nutating disc types. Both of these meter types use the rotary or reciprocating movement of an internal mechanism placed in the water flow path to advance the readout. This meter type will typically feature an internal sieve or filter to stop small stones and grit from damaging the internal moving parts.
Velocity volume meters include variants such as single- and multi-jet meters. These meters feature one or several internal ports that direct a jet of water against an impeller that then rotates and drives the metering mechanism. Other types of velocity meters include the electromagnetic and ultrasonic meters that use ultrasound or electromagnetic induction to measure the fluid volume. This type of volume meter is particularly well suited to waste water applications, as there are no internal moving parts to be damaged or clogged by suspended solids.