D3 Prep Water Meters

Meter Yoke

• A special device that assists in the installation of small meters and helps protect them.

• Yoke holds the stub ends of the pipe in proper alignment and maintains proper spacing to support the meter.

Positive Displacement Meter

• The most commonly installed water meter.

• Used primarily for residential metering

• Water moves through a chamber of known volume and causes piston or disc to move as it passes through

• Movement of disc/piston is transferred to register which totalizes the volume of water that has passed through the meter.

• Sizes ranges from 3/5 of an in to 2in

• After time goes on meter experiences wear, they will register less than the actual volume of water passing through them

• Not intended for continuous, high flow rates applications since it will damage the meter, it should also not be operated @ max capacity for very long

Compound Meter

• A combination of two meter (positive displacement and turbine) designed to accurately measure flow over a wide range.

• Used in applications where the customers usage varies widely throughout the day

• The three main parts to meter are the turbine meter, positive displacement meter and an automatic valve arrangement.

• During high flow rates the auto valves allows the water go thur the turbine meter and when flow is reduced the auto valve closes and diverts flow thur positive meter.

Current Meter

• A propeller or turbine type of meter used to meter the water going to large industrial customers that continuously take large volumes of water.

• Accuracy of meters drops off significantly as the flow rate drops to the lower end of the meter’s limit

• Good practice to add strainer prior to meter to protect it from sediment

Detector-check Meter

Used in applications where daily use is low, but an emergency condition may require high flow rates

• Ex: Fire suppression sprinkler system

• under normal conditions, water usage is metered by a positive displacement type meter due to check valve that doesn’t open until low pressure conditions due to fire flow requirements are detected

Turbine Meter

Flowing water turn a rotor that is recorded on the flow meter’s register; the revolutions are almost directly proportional to the volume of flow.

• Used in large applications.

MultiJet Meter

Uses a multiblade rotor that is mounted on a spindle within cylindrical measuring chamber.

Propeller Meter

Flowing water causes a propeller to rotate and this movement is transmitted to the register to record the flow volume.

• Used when flow is fairly consistent and does not change abruptly

Proportional Meter

Has a restriction in the pipe that requires a portion of the flow to go through a meter and be recorded.

• Requires a multiplication factor to calculate the actual flow through the system and used for large flow applications.

Venturi Meter

A tapered constriction in the pipeline that creates a pressure differential that changes depending on the rate of flow through it.

Orifice Meter

A thin plate that restricts flow through the system and creates a differential pressure on each side of the plate.

• This differential pressure is proportional to the flow rate.

Magnetic Meter

Utilizes a magnetic field to measure flow based on the principle that relative motion between a conductor (water) and a magnetic field will induce a voltage.

• The voltage produced is proportional to flow.

Ultrasonic Meter

Uses sound waves to measure flow by utilizing the Doppler effect.

• The flowing water changes the frequency of the sound waves and this frequency change is proportional to the flow rate.

Customer Metering

• Most water systems meter the water that is delivered to each customer for the purpose of billing and monitoring for watering loss.

• The volume of water used and the rate of usage will determine the type of meter installed at the customer’s location

Positive Displacement Piston Meter

Moves back and forth as a known volume of water passes through, each rotation is transferred to the register through a magnetic drive and gears and is recorded.

Positive Displacement Nutating-disc

A flat disc is placed within the measuring chamber and rotates (wobbles) as water flows through. Rotation is transferred to the register where the volume is recorded.

Larger customer meters options

• Compound Meters

• Current-Meters

• Detectors-check Meters

Meter Selection

• Depends on expected maximum demand

• Normal system pressure

• Friction losses in line

• Ranges of flow rate expected

• its normal to install a meter that is one size smaller than the service line.

Residential meters sizes

Positive displacement meters are either 5/8 or ¾ of an inch in size

Commercial meters

Positive displacement meters that are 1, 1 1/2, or 2in are commonly used for apartment buildings, businesses, public buildings & small industries.

Commercial Meter guidelines

• If the flow rate will range between 5% & 35% of the meter’s rated capacity and accuracy at very low flow rates is not important, then a positive displacement meter should be used.

• If accuracy at low flow rate is required and a large capacity is needed, a compound meter is the best choice.

• If a large capacity is the main requirement and flow will be greater than 10% of max rating, then a turbine meter is the best choice.

Installation Locations

• Has many options of placement, can be installed indoor or outdoor

• Commercial & residential installations in areas that have strong winters often reside indoors, in warmer there usually located between the curb and sidewalk.

Indoor Installations

• Pipes first enters the building

• must be located where can be accessed for reading & repair

• If the building electrical system uses the plumbing system as a ground & meter yoke as a ground and meter yoke isn’t in use, electrical ground must be installed across the meter.

Outdoor Installations For Small Meters

• Locate meter on public property if possible

• locate away from vehicle traffic

• Box lid should be fit tightly and be flush with ground

• Piping should be 1-2in away from the meter box side in areas where ground frost is a problem

Outdoor Installations For Large Meters

• Are no standards but some recommendations should be followed

• Meter must be properly supported so as not to put stress on the water piping

• There must be adequate work space in the vault

• 20in vertical wall clearance & 24in of head space

• Test valves should be installed to allow for volumetric tests & thrust blocking should be installed with meters as required