Section 6. METER TYPES
1. CATEGORIES OF METERS. Meters discussed in this manual fall under two
categories: those used for electric energy and those that measure fluid flow.
1.1 Electric Meters. The basic meters used in an electric energy management
Kilowatthour Meter: Measures the total power consumed.
Demand Meter: This meter, usually part of a kilowatthour meter,
measures the average power consumption over specific time periods.
Power Factor Meter: Power factor meters, located where the main
service enters the facility, permit continual monitoring of the power
factor for the entire installation. The data contribute to computing
Power Survey Recorders and Analyzers: Typically monitor and record
several parameters such as load power, real power, reactive power,
apparent power, power factor, and voltage and current for single-,
two-, and three-phase circuits.
Ammeters: Used to measure current flow to identify and isolate system
or equipment energy losses.
1.2 Steam, Water, and Gas Meters. Steam, water, and gas flowmeters can be
categorized by principle of operation, which yields the classifications
below. Table 2-1 is a compilation of important parameters for these types of
Differential Pressure Meters: These are the most common type meters
in use and include orifice, venturi, flow nozzle, and pitot tube.
Used to measure the difference in pressure between two points in the
Positive Displacement Meters: Oscillating piston and nutating disk
meters are most often used in the measurement of potable water.
Diaphragm meters are used in the measurement of natural gas.
Velocity Meters: Turbine, vortex shedding, electromagnetic, and sonic
design type meters have widespread application.
Open Charnel Meters: This type of meter is used almost exclusively to
measure waterflow in open conduits where a full flow is not required.
Characteristically, three sides of the flow are bound by some type
of wall with the remaining side being a free surface. Typical open
conduits include tunnels, nonpressurized sewers, partially filled
pipes, canals, streams, and rivers. Meters of this type are weirs and