Techtrol VFSL Instruction Manual

Vibrating Fork Point Level Switch for
Liquids – VFSL

1. Operation

The electronically stimulated fork vibrates at it's mechanically resonance frequency of approx.330 Hz. If the
liquid media covers the fork, the damping of the vibration is detected electronically and a corresponding signal
output is actuated. The vibration of the fork has self-cleaning properties. The light deposit on the container
wall does not affect the operation of switch.
Switch is available in two constructions
1) Two part system as sensing fork probe and controller
2) Integral system with built in controller

1.1. Applications

All types of liquids, Plastic industry, powder, granular etc. Light free flowing power etc.

2. Installation

The switch has screwed mounting, which can be side mounted on the container wall at the desired level of the
material to be controlled. The fork tines should be horizontally or pointed slightly downward. It can be also
mounted from tank top.
2.1 Precautions during Installation –
 The tines should not be bent or position distorted.

During filling operation, the material should not fall directly onto the tines. Otherwise protection
shield should be provided over the tines.
 During installation of probe with screwed mounting, turn the hexagonal mounting nut of the probe
and not the housing.
 For side mounting location the tines position should be such that the material can flow freely
through them.
 The knife-edges of the tines should face the ground plane in horizontal mounting position.
 The tines should extend far enough into the vessel so that they are free to vibrate despite the
build-up on the vessel wall.
 The extended probe should be mounted in such a way that it does not extend further than
necessary in the vessel.
 Turbulence during pneumatic conveying can cause operational problems and can be avoided by
shielding the tines by windscreen.
 For remote mounting of the electronics switching unit/ controller, the probe connection cable gland
of the Cast Aluminum housing of the Switching unit should point towards ground plane.
INSTRUCTION MANUAL
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