The RNG/RWG/RWBG series vortex shedding flow meter family is designed to provide accurate and repeatable gas flow
measurement. These meters employ a patented ultrasonic technique to measure a form of turbulence created in the flow
stream. This turbulence, known as the Von Karman Vortex Street, is related to the flow through the pipe.
The RNG/RWG/RWBG series flow meter is a microprocessor based device, with HART compatible communications. The
primary output of the meter is a 2 wire, 4…20 milliampere (mA) current which is proportional to the flow.
With HART communications, users have the capability to remotely configure the meter. Typical operations, like re-scaling the
analog output, can be performed in comfort using a standard PC or HART 275/375/475 Communicator.
The wafer style meters are for pipe diameters four inches or less, and are installed between 150 lb flanges, or are
manufactured with pipe extensions and 150 lb flanges welded on the ends. These meters are calibrated in volumetric flow
units, that is Actual Cubic Feet per Minute (ACFM). Flow rates for the wafer style meters are listed in Table 2 .
The insertion style meters are retractable meters that are installed through the walls of a pipe or duct larger than four inches.
These meters can be installed through a 2 in. full port valve, which permits the unit to be retracted or inserted manually
without shutting down the system. Flow rates for the Insertion style meters are shown in Table 3.
DANGER
CAUTION SHOULD BE USED WHEN INSERTING OR RETRACTING AT PRESSURES EXCEEDING 60 PSIG (4.14 BARG).
SPECIFICATIONS
WaferInsertion
Mounting Requirements Mounts between two 150 lb. flanges Options for 2 in. NPT, 2 in. 150# Flange, 2 in. 300# Flange, DN50 Flange
Operating Pressure–5…250 psig (–0.34 …17 barg)
Operating Temperature–20…300° F (–28…150° C)
Ambient Temperature–20…155° F (–28…68° C)
Accuracy±1% of Reading over the upper 90% of the flow range
Flow measured in feet / second @ 14.69 psia, 60° F (meter / second
@ 1.013 bar, 16° C)
Pipe Size
in. (mm)
4 (102)
6 (152)
8 (203)
10 (254)
Table 3: Velocity Ranges for RNG Series
Velocity fps (mps)
MinimumMaximum
2 (0.6)140 (43)
Page 5 June 2018VRX-UM-00374-EN-06
Page 6
Installation
INSTALLATION
The flow meter is shipped completely assembled, tested and ready to install in its permanent location. See Figure 2 on page
7 through Figure 5 on page 9 for the applicable outline dimensions for specific meters.
Straight-Run Piping Considerations
The sensor should be installed with 20 diameters, or more, of straight, unobstructed, full area pipe upstream of the flow meter
installation and 10 diameters, or more, downstream. This condition provides the fully developed, symmetrical flow profile that
is necessary to obtain accurate and repeatable results. The first obstruction up and downstream should be a full area elbow. If
the minimum straight run is not possible, the general rule is to have 80% of the straight run upstream and 20% downstream
from the flow meter installation.
High intensity ultrasonic noises should not be located upstream or downstream from the sensor. Common ultrasonic noise
sources include the following:
• Slightly cracked valves operating with large pressure drops.
• Small pipe leaks in high pressure systems.
• Venturies operating at near-sonic flow rates.
• Sonic nozzles.
If these ultrasonic noise sources cannot be eliminated, the meter should be mounted with at least one elbow between the
flow meter and the noise source.
Installation Location
The RNG/RWG/RWBG series meters uses ultrasonics to measure flow. An ultrasonic noise can interfere with this technique,
therefore high intensity, ultrasonic noise sources should not be located upstream or downstream from the meter. Common
mechanical ultrasonic noise sources include the following:
• Slightly cracked valves operating with large pressure drops.
• Small pipe leaks in high pressure systems.
• Venturies operating at near-sonic flow rates.
• Sonic nozzles.
If these ultrasonic noise sources cannot be eliminated, the meter should be mounted with at least one elbow between the
flow meter and the noise source.
Temperature and Pressure Tap Locations
User supplied pressure and temperature sensors should be mounted downstream from the flow meter. The pressure sensor
should be approximately 3 to 5 pipe diameters and the temperature sensor approximately 4 to 8 pipe diameters downstream.
Mechanical Installation
The meter should be installed with at least 20 pipe diameters of straight pipe upstream and 10 pipe diameters downstream.
This condition provides the fully developed, symmetrical flow profile that is necessary to obtain accurate and repeatable
results. Shorter upstream/downstream piping may be used although a shift in calibration may occur. If severe turbulence or
distorted flow profiles are present, flow straighteners should be used. See “Additional Installation Requirements” on page 17
for additional information.
Page 6 June 2018VRX-UM-00374-EN-06
Page 7
Installation
FlowFlow
RWG/RWBG Wafer Meter Installation
The labeling of the flow direction on the meter should be aligned with the flow in the pipe. If liquids or condensate can be
present in the flow, the meter should be installed so that liquids will not accumulate on the ultrasonic transducers (the small
buttons on either side of the vortex strut).
The RWG/RWBG series wafer meters are designed to mount between two ANSI 150 lb flanges. The meter should be mounted
so its inside diameter is centered inside the pipe. See Figure 1.
OTE:NGaskets (not provided) are necessary between the sensor and the ANSI flanges. Ensure that these gaskets are
properly installed and do not protrude into the flow stream.
The RWGxxF series flanged meters are designed to mount between two ANSI 150 lb flanges. See Figure 4 on page 8.
OTE:NGaskets (not provided) are necessary between the ANSI flanges. Insure that these gaskets are properly installed and
do not protrude into the flow stream.
AVOID BENDING THE VORTEX STRUT OR DAMAGING THE TRANSDUCERS DURING INSTALLATION. DO NOT REMOVE
COVER PLATES WHILE UNIT IS OPERATING.
4.38"
+.12
C
-.00
CORRECT
(Meter Centered In Pipe)
Figure 1: Wafer position in the piping
5.75
Cable Entry
Accommodates
.19/.25 Dia Cable
3/4 -14 NPT Connector
The RNG series insertion meters are designed to mount on a standard ANSI 150 lb, 2 in. pipe flange. If the main line can be
depressurized easily, then a simple installation consisting of a 2 in. nozzle and a 2 in. ANSI 150 Class flange may be used. This
permits the shortest shaft length which minimizes the clearance space. The measuring window should be installed in the
center of the line for line sizes 12 in. or less (see Figure 5 on page 9). For line sizes larger than 12 in., the measuring window
should be installed 25% to 50% of the way into the pipe. It is recommended that the internal dimensions of the line be
measured for accurate readings.
Insertion meters can be used in any size pipe four inches and larger in diameter. In order to calculate accurate volumetric,
mass, and standard flow measurements, it is recommended to enter the exact pipe size into the meter. Normally this
operation, along with overall meter configuration, is performed at the factory. However, the user can enter the pipe diameter
on site using the Badger Meter HART Interface or a HART 275/375/475 communicator.
OTE:NThe torque requirement for the Conax fitting is 90…100 ft-lb. See Figure 5 on page 9. See “Additional Installation
Requirements” on page 17 for additional installation information and flow profiling.
C Maximum
Retracted
B Maximum
13.0" Maximum at
Maximum Insertion
4.50" Maximum
Retracted
Insertion
4.38"
5.75
FLOW
.75"
4.50"
Maximum
FLOW
Figure 5: Outline dimensions for RNG insertion meters
Where de-pressurizing the line for flow meter maintenance is impossible or undesirable, the “hot tap” method of installation
is used. This method involves inserting the flow meter through a 2 in. (51 mm) spool piece and a 2 in. (51 mm) full port valve
and will require a longer shaft length as well as greater clearance space for removal and installation.
DANGER
CAUTION SHOULD BE USED WHEN INSERTING OR RETRACTING AT PRESSURES EXCEEDING 60 PSIG (4.14 BARG).
Figure 6 shows a sample hot tap installation. With the exception of the spool piece, which must be a minimum of
4.5 in. (114.3 mm), all of the dimensions are suggestions only. Actual dimensions may vary depending on customer’s own hot
tap configuration.
To calculate the required insertion flow meters stem length:
• For pipe diameters less than or equal to 24 in. (609 mm): Calculate the distance from the center line of the pipe to the top
of the flow meter mounting flange.
• For pipe diameters greater than 24 in. (609 mm): Calculate the distance from the top of the flow meter flange to a point
1/4 of the pipe diameter into the pipe.
When flow profiling is required, calculate the distance from the bottom of the pipe to the top of the flow meter mounting
flange and subtract 2 in. (51 mm). Next round this distance up to the next largest 12 in. (305 mm) increment. This is the stem
length that should be ordered.
Determined
By Stem
Length
Spool Piece
4.50" Minimum
2" Full Port
Valve
4.38"
13.05" Maximum at
Maximum Insertion
FLOW
5.75
Cable Entry
Accommodates
.19/.25 Dia Cable
3/4 -14 NPT Connector
Standard ANSI
2 Inch 150 Lb. Flange
4.50" Maximum
Retracted
Determined
By Stem
Length
4.50"
Maximum
Flow
Figure 6: Hot tap configuration for RNG insertion gas meters
DANGER
USE CAUTION WHEN INSERTING OR RETRACTING AT PRESSURES EXCEEDING 60 PSIG (4.14 BARG).
Page 10 June 2018VRX-UM-00374-EN-06
Page 11
Electrical Installation
ELECTRICAL INSTALLATION
Electrical connections for the meter are made using screw terminals located inside the enclosure. To access these terminals,
remove the lid from the enclosure. The functions of these terminals are illustrated in Figure 7.
To install the cable, route it through the cable entry located on either side of the enclosure and attach the wires to the
appropriate terminals.
EMC NOTIFICATION
The ultrasonic sensing technology employes a 160 kHz carrier frequency and the flow meter is sensitive to radiated and
conducted noise at or near this frequency. Precautions must be taken not to subject the flow meter or associated cabling
to sources of RF noise that could interfere with the ultrasonic carrier. Any such interference can cause degradation in flow
meter performance.
+
4-20MA
NC
EP RTN
EP PWR
EP OUT
EP IN
Cable Shield
Ground
Chassis
Ground
Figure 7: Flow meter terminal functions
Terminal
Designator
Function
4-20 mA +Loop Power (+28 VDC maximum)
4-20 mA –Loop Power (–)
NCNot Used
EP RTNPressure Sensor Power Supply Return
EP PWRPressure Sensor Power
EP OUTPower Out to Pressure Sensor
EP INPressure Sensor Input
The vortex meter is available in two versions: CE or intrinsically safe for hazardous areas. A display is not available with the
intrinsically safe meter. The nameplate specifies the certifications that apply to the meter. Te electrical installation instructions
for both types of meters are the same, except the intrinsically safe meter has special consideration specified in this user
manual and in the control drawing accompanying the meter. The CE version is shown below.
Page 11 June 2018VRX-UM-00374-EN-06
Page 12
Instructions Specic to Hazardous Area Installations
INSTRUCTIONS SPECIFIC TO HAZARDOUS AREA INSTALLATIONS
See the European ATEX Directive 94/9/EC, ANNEX II, 1.0.6 and the Vortex Intrinsically Safe Flow Meters Control Drawing for
RWG, RWBG and RNG Meters (shipped with the product; also available at badgermeter.com).
The following instructions apply to equipment covered by certificate number SIRA 03ATEX2543.
1. The equipment may be used in zones 1 and 2 only with ammable gases and vapors with apparatus groups IIA and IIB and
with temperature classes T1, T2, T3 and T4. It is not suitable for zones where IIC gases or vapors may be present.
2. The equipment is only certied for use in ambient temperatures in the range –40° F (–40° C) to +176° F (+80° C) and should
not be used outside this range.
3. The equipment has not been assessed as a safety related device (as referred to by Directive 94/9/EC ANNEX II, Clause 1.5).
4. Installation, inspection and maintenance of this equipment shall be carried out by suitably trained personnel in
accordance with the manufacturer’s instructions and the applicable codes of practice (e.g., EN 60079-14 and EN 60079-17
in Europe).
5. Only spare parts supplied by Badger Meter may be used and installed in accordance with Badger Meter instructions.
The certification marking is as follows:
WIRING
A two conductor foil shielded cable made of 14…22 AWG solid or stranded wire is required to make connections to the flow
meter (for example, Consolidated Wire P/N 5573-CL).
The shield is required to be attached to one of the shield ground points as illustrated in Figure 7 on page 11. The other end
of the shield should not be grounded.
When using the Zener Diode Barrier the maximum load resistance for the power depends on the supply voltage (see Figure 8
on page 14).
If a Barrier/Isolator is being installed, refer to the Barrier/Isolator manufacturers data sheet for maximum resistive loading on
the output. (Excitation voltage input to meter must be 15V DC minimum when output is at 20 mA)
The flow meter requires a minimum of 15V DC at the meter’s 4…20 mA (+) and (–) terminals to operate. With all loop loads
installed in the loop, the voltage at the meter must be at least 15V DC or the meter will operate erratically if at all. The
maximum load resistance for the meter depends on the supply voltage. The higher the supply voltage the greater the loop
load the meter will support.
The current sense resistor used in HART communications should be installed only for setup or troubleshooting as the current
sense resistor is an unnecessary loop load when the meter is operating under normal conditions.
OTE:NCurrent loops with large loads may work satisfactorily at low loop current outputs but cease to function as the output
current increases. The reason for this is that as the current increases the voltage drop across the sum of the loop loads
will increase in direct proportion to the current output. At some current output unique to that particular loop the
voltage drop across the sum of the loop loads will leave less than the minimum 15V DC required at the meters input
terminals.
If this occurs, the loop load must be reduced enough so that—at the maximum current output for the system—the
voltage at the meter’s power input terminals remains at least 15V DC
The external pressure sensor is limited to a 5 foot (1.5 meter) cable length.
Page 12 June 2018VRX-UM-00374-EN-06
Page 13
Operation
Various wiring configurations are shown in Figure 8 on page 14 and Figure 9 on page 15.
OPERATION
Power Terminals
The 4…20 mA terminals (+ and –) are used for the flow meter’s power supply.
Current Output
The current output is accessed through the 4…20 mA + and – terminal loop and provides an output current proportional to
the flow measured by the meter. This output is a standard 4…20 mA output, where 4 mA corresponds to no flow and
20 mA indicates 100 percent (full scale) flow. The current output will not be accurate if the load resistance on the current
output terminal is too high.
Load Table for Flow Indicator or Control System Using
Zener Diode Barrier
Power Supply Voltage24 V26 V
Maximum Voltage Drop3 V5 V
Maximum Resistances136 Ω225 Ω
For Loads Greater Than 225 Ω, see Optional Wiring Diagram
Figure D - Load TABLE
Table 4: Load table
Barriers and Barrier Isolator Examples
Stahl9001/01-280-100-101 Zener Barrier
TurckMK33-221-Ex0-HL/24V DC (2 Channel)
TurckMK33-111-Ex-HLi/24V DC (1 Channel)
Table 5: Barriers and isolator examples
HART Communication
The vortex meter has the capability of HART Communication. However, it is not required that it be used. In most cases, the
meter is configured at the factory per the customer’s specifications. The user need only install the meter and connect power.
If HART Communication is desired a current sense resistor must be placed in series within the current loop.
The value of the resistor can range from 170…600 Ω and be rated at 0.25 watt or larger. The placement of the resistor is
illustrated in the wiring diagrams. The resistor will add to the total loop resistance and will raise the value of the required
power supply voltage if it remains in the loop.
There are two ways to communicate to the meter via the HART interface: the Badger Meter HART Interface or a
HART Communicator. The Badger Meter HART Interface is a PC-based software program that runs on Windows® 98,
Windows NT, Windows ME, Windows XP, Windows Vista® and Windows 7 operating systems.
The HART 275/375/475 Communicator is a handheld device that can communicate with any HART device that is registered
with the HART Communication Foundation. The HART 275/375/475 Communicator also provides access to all settings that
can be configured by the user. The 275 provides a menu driven interface. See Figure 10 on page 16 to view the menu map
for the HART 275 Communicator.
OTE:NHART 275 Communicator requires Badger Meter drivers for proper communications. (See communicator owner’s
manual for driver listing).
Page 13 June 2018VRX-UM-00374-EN-06
Page 14
Wiring Diagrams
WIRING DIAGRAMS
The wiring diagrams illustrated below are for installations where no 4…20 mA pressure sensor is used.
Optional wiring diagram for loads > 225Ω
Figure 8: Without 4…20 mA output pressure transducer
Page 14 June 2018VRX-UM-00374-EN-06
Page 15
Wiring Diagrams
If an analog pressure gauge is used, it must be wired as shown below to avoid inadvertent current paths.
A single supply can be used to power the flow meter and the external pressure sensor. The 4…20 mA flow indication must be
taken from the source side of the loop.
Badger Meter Vortex flow meters are designed to ensure long term accuracy and reliability. The stainless steel body and selfcleaning strut are specifically designed to withstand the rigors of industrial environments. As a result, periodic adjustment or
re-calibration is not normally required. Technical assistance is also available directly from Badger Meter, providing complete
re-calibration and repair service for the flow meter at a reasonable cost.
Preliminary Checks
DANGER
DO NOT OPEN ENCLOSURE IN HAZARDOUS AREAS WITH POWER APPLIED.
• Is the flow meter cable installed correctly?
• Is the proper power supplied to the proper terminals?
• Is the flow meter wired for 2 wire 4…20 mA operation.
• Is the shield tied to the shield ground terminal and only the shield ground terminal?
ADDITIONAL INSTALLATION REQUIREMENTS
Introduction
Installing a flow meter is something which requires careful consideration. It cannot just be placed in a line somewhere and
be expected to fulfill its purpose adequately. The geometry and condition of the pipe runs in the area of the installation must
be considered to ensure the best and most accurate operation of the flow-meter. This appendix provides suggestions for
optimum installations.
Most flow meter manufacturers define installation conditions in terms of upstream and downstream straight pipe lengths
from the point of installation. Unfortunately this is not the only requirement, and one needs to consider other peripheral
conditions, such as proximity and style of bends, and other equipment installed in the line. By doing this, you avoid problems
of turbulence, swirl, and sonic noise.
Turbulence
Turbulence is a disturbance of the flow caused by bends and obstructions in the flow stream (it is this phenomena which
makes the vortex flow meter work). Fortunately turbulence dies out fairly quickly, so by positioning the flow meter well away
from bends and obstructions this potential problem of measuring flow in turbulent conditions is overcome (see Figure 12).
Swirl
Unlike turbulence, swirl will not die away. Once created it will continue until dissipated on the next pipe bend in the system.
Swirl occurs after two bends, in close proximity, which are at an angle to each other. When designing an installation, keep the
flow meter out of any line which has two adjacent bends upstream (see Figure 13).
Sonic Noise
Sonic noise is created by valves (either flow control or pressure control valves) which are slightly open. Like swirl, sonic noise
will only dissipate on a bend so it is important to install flow meters out of the line of sight of valves. Sonic noise is caused by
liquid attaining sonic velocities through a slightly open valve that has a pressure difference across it. This noise travels both
up and down stream from the valve so you have to ensure that the flow meter is installed well away from the valve, preferably
around a bend (see Figure 14).
Velocity Prole
When using an RNG series insertion flow meter, it is necessary to consider the effects of the velocity profile across the pipe or
duct to optimize accuracy.
Page 17 June 2018VRX-UM-00374-EN-06
Page 18
Additional Installation Requirements
In large pipes, the flow moves slowly at the pipe walls but is at maximum velocity in the center of the pipe creating a
continuously variable velocity across the pipe (see Figure 11). This velocity variation is called the velocity profile of the pipe,
and can be measured and plotted by using the insertion flow meter to measure velocities at various noted positions across
the pipe. As the maximum velocity is in the center of the pipe, it follows that if the flow meter is positioned in the center, it will
not measure average flow. The rule-of-thumb position is 25% of the way into the pipe, but the optimum position can only be
obtained by measuring the profile and working out the correct position from that.
1⁄8
¼
½
Flow
Figure 11: Typical velocity profile
Figure 12: Turbulence caused by bend or obstruction
Figure 13: Swirl caused by two bends in different planes and in close proximity to one another
Figure 14: Upstream/downstream sonic noise caused by slightly opened control valves
Page 18 June 2018VRX-UM-00374-EN-06
Page 19
Additional Installation Requirements
Flow Proling
If the flow meter is long enough to be inserted to the far side of the pipe, the flow through the pipe may be profiled at various
flow rates. The goal is to find a point in the pipe that remains a consistent percentage of the average flow rate over a wide
range of flow. A sample flow profile is shown in Table 6. In this example, the flow rate of a 48 in. pipe is measured every six
inches across the diameter of the pipe beginning and ending 3 in. from the near and far sides of the pipe. The distance in
inches from the nearside of the pipe is shown. Measurements are taken at a low, medium and high average flow. In Table 7,
the flow rate at each measurement point has been converted to a percentage of the average flow. It can be seen that point
number three (15 in. from the near side of the pipe) reads a consistent 102 percent of the average flow. The meter should be
placed in this position and the output should be divided by 1.02 to obtain the correct reading. Flow profiling will generally
improve measurement quality in insertion meter installations.
Flow
Low Flow1.902.002.042.062.062.042.001.902.0
Medium Flow5.585.916.126.216.246.186.065.706.0
High Flow10.9211.7012.2412.4812.6012.4812.1811.4012.0
Distance (in)39152127333945
Medium Flow93.098.5102.0103.5104.0103.0101.095.0
12345678Average (FPS)
Flow
12345678
Low Flow95.0100.0102.0103.0103.0102.0100.095.0
High Flow91.097.5102.0104.0105.0104.0101.595.0
Table 7: Flow profile normalized data
Flow Rate at Measurement Point (FPS)
Table 6: Flow profile raw data
Flow Rate at Measurement Point (%)
Reducing the Pipe Diameter
To decrease the variation of flow profile, the piping can be narrowed at the flow meter as shown in Figure 15. This will smooth
the flow and increase the effectiveness of flow profiling. Nearly any angle can be used on the down-stream side of the meter
to restore the original pipe diameter. However, if the angle of piping is seven degrees or less, nearly all the pressure drop
caused by the narrow pipe section will be recovered.
Figure 15: RNG insertion gas meter installed in a reduced pipe