KROHNE VFM 3100 EN - Manual (Page 6)

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1. Installation
1.1 Introduction
1.1.1 Description
The VFM 3100 F/W-T (Figures 1 and 2) measure fluid (liquid, gas, or
steam) flow rates using the principle of vortex shedding.
Fluid flowing through the VFM 3100 body passes a specially shaped
vortex shedder that causes vortices to form and shed alternately
from the sides of the shedder at a rate proportional to the flow rate of
the fluid. These shedding vortices create an alternating differential
pressure that is sensed by a detector located above the shedder. A
pulsed voltage is generated by the detector with a frequency that is
synchronous with the vortex shedding frequency. This voltage is then
conditioned by the electronic module to produce either a pulse rate
signal or an analog (4 to 20 mA dc) signal.
1.1.2 Fundamental Installation Requirements
Meters shall be installed to meet all applicable local installation regu-
lations, such as hazardous location requirements, electrical wiring
codes, and mechanical piping codes. Persons involved in the instal-
lation should be trained in these code requirements in order to ensu-
re that the installation takes maximum advantage of the safety fea-
tures designed into the VFM 3100.
Figure 2. VFM 3100 W-T Sandwich Body Figure 1. VFM 3100 F-T Flange Body