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 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
program are:
Kilowatthour Meter: Measures the total power consumed.
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Demand Meter: This meter, usually part of a kilowatthour meter,
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measures the average power consumption over specific time periods.
Power Factor Meter: Power factor meters, located where the main
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service enters the facility, permit continual monitoring of the power
factor for the entire installation. The data contribute to computing
consumer billing.
Power Survey Recorders and Analyzers: Typically monitor and record
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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
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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
meters.
Differential Pressure Meters: These are the most common type meters
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in use and include orifice, venturi, flow nozzle, and pitot tube.
Used to measure the difference in pressure between two points in the
system.
Positive Displacement Meters: Oscillating piston and nutating disk
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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
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design type meters have widespread application.
Open Charnel Meters: This type of meter is used almost exclusively to
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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
flumes.
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