Badger Meter Vortex Meters - Manual (Page 4)

2 Form No. 09-VRX-UM-00007
GENERAL INSTALLATION INFORMATION
Prior to installation, the following items should be considered.
1) The vortex transmitter contains electronic circuitry which can be affected by high electromagnet-
ic or electrostatic fields. Care should be taken to locate the installation in an area away from large
electrical motors, transformers, or other devices which can produce such interference.
2) Proper grounding is required to eliminate electrical noise which may be present within the fluid
and piping system or in the near vicinity of the vortex transmitter. For non-conductive piping sys-
tems, an exterior grounding strap should be used to provide a path to earth ground. For conduc-
tive piping systems, a properly grounded pipe will require no additional preparation.
FLOW RATE AND RANGE REQUIREMENTS
Most manufacturers state flow range capabilities by publishing the maximum allowed flow rates. Then
they provide a turndown ratio to determine minimum flow rate. To use the turndown ratio, simply divide
the maximum rate by the ratio to determine the minimum rate. Racine vortex flow meters have a 12:1
turndown ratio at a viscosity of 1 cSt. Higher viscosities will reduce the turndown.
NOTE: The ¼” NPT and ½” flare end meters have a standard turndown ratio of 8:1
PIPING REQUIREMENTS
Turbulence in the pipe line can affect the accuracy of most flow meters. Sources of turbulence are
pumps, valves, or changes-in-direction in the line. To avoid these potential problems, it is standard prac-
tice to place the meter a certain distance from the turbulence source. These distances are indicated in
Pipe Diameters (PD). For example, 10 PD means place the flow meter ten times its inside diameter away
from the source of turbulence. Downstream distances between the meter and a valve or a change-in-
direction must also be followed.
The best accuracy is achieved with at least 20 PD upstream and 5 PD downstream for RVL vortex flow
meters. If an upstream elbow is closely coupled to another elbow creating a change in plane, 27 PD is
required upstream and 10 PD downstream. (see Figure 2, 3, and 4)
When the diameter of the meter is smaller than the pipe line, at least 20 PD of pipe with the same diam-
eter as the meter upstream, and 2 PD downstream is needed. Overall, 25 PD of straight run prior to the
meter is required (see Figure 5). If there is a plane change in the installation, this IN OUT requirement in-
creases to 25 PD upstream (30 overall). The downstream requirement is now 2 PD of pipe with the same
diameter as the meter, and a minimum of 5 PD overall of straight run. If there is a valve downstream the
usual 10 PD between the meter and a valve is still required.
If the required piping parameters are not met, there will be a reduction in accuracy.
NOTE: Pulsating flow will affect accuracy (pressure pulses will not).