Greyline Instruments DFS 5.1, User Manual

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DFS 5.1 Doppler Flow Switch
TRANSDUCER INSTALLATION
MOUNTING LOCATION
- The position of the sensor is one of the most important considerations for
reliable flow monitoring. The same location guidelines apply to Doppler as to most other types of flow
switches.
VERTICAL OR HORIZONTAL PIPE - Vertical pipe runs
generally provide evenly distributed flow conditions. On
horizontal runs the sensor should be positioned at 3 or 9
o’clock to avoid concentrations of gas at the top of the pipe
and solids on the bottom.
Generally the sensor must be mounted away from flow disturbances such as valves, pumps, orifice
plates or venturis which tend to increase flow velocity or cause cavitation. Velocity increasing devices
often cause cavitation and erratic operation. As a guideline, mount the sensor 20 diameters upstream and
30 diameters downstream from velocity increasing devices.
Turbulence Increasing Devices: Elbows, flanged
connections and tees tend to introduce desirable
conditions of an evenly distributed flow profile with
some air or gases entrained in the flow. Sensor
mounting
6 diameters upstream and 10 diameters
downstream from these disturbances is generally
optimum.
The transducer is designed to mount longitudinally on a straight section of pipe. Do not attempt to
mount it on bends, elbows or fittings. The DFS senses flow in either direction.
Prepare an area 2 inches wide by 3 inches long for transducer bonding by removing all paint, scale and
rust. Thoroughly degrease the surface to which the transducer will be bonded. The objective of site
preparation is to eliminate any discontinuity between the transducer and the pipe wall which would
prevent acoustical coupling.
For semi permanent or temporary bonding, the following are recommended:
a) Dow Corning silicon compound #4. (Greyline Part #CC)
b) Electrocardiograph gel.
c) Petroleum gel.
The above are arranged in their order of preferred application. B & C are suggested only for room
temperature application.
DO NOT USE: Silicon RTV compound (silicon rubber) .