MOLLET VF6 Vibro Level Indicator Instruction Manual

MOLLET VF6 Vibro Level Indicator

Safety instructions

1. The installation, initial operation and maintenance must be done by a qualified expert with electrical know-how.
2. Check before installation whether the measuring device is in compliance with the specification of the point of measurement as process and ambient temperature as well as the measuring range.
3. Use in potentially explosive atmospheres only devices with W – identification marking.
4. For the electrical connection take notice of the local and statutory rules and regulations and/or the VDE 0100.
5. Consider the data of the name plate on the device.
6. A fuse (max. 4 A) and a main switch have to be connected in series to the voltage supply.
7. Switch off the voltage supply before you open the measuring devive (dangerous voltages in case of contact).
8. Check the cable entry, cable gland and clamping nut, to see if they are sitting correctly and are sealed.
9. Put the device into operation only when the unit is closed and the cover sealing is intact.
10. Changes and repairs of the device are allowed only in so far as it is permitted in the operating instructions.

Prior to the use of the device in potentially explosive atmospheres please, read and obey the

Special conditions and guidance for safe use in the attached Explosions protection information and observe the operating instruction.

Use of the device

Intended use

• The device is used as a level limit switch for bulk solids in silos, bins and so on.

Normal operation

• Please operate the measuring device only according the intended use.
• Use the measuring device only within the specified temperature ranges for process and ambience.
• Protect the electronics compartment against pollution.
• In case the measuring device becomes damaged, please stop operation immediately.

Improper use

• Ignoring safety regulations and operating instruction.
• Operation of the measuring device in inappropriate use.
• Installation of spare parts that are no original parts.
• Removal, addition or modification of components as far as it is not described in the documentation of the manufacturer.
• Violation of applicable standards and laws.

Receiving department and storage

Receipt of goods

• Please check whether packaging or content are damaged.
• Please check whether the supplied goods are incomplete or do not comply the requirements as set out in your order.

Storage

• For storage and transportation the measuring device has to be packed shock-resistant.
• Store the device at a place protected against moisture and dust.
• Take care that the probe will not be bended.
• Temperature range for storage -40 °C … +85 °C

Function

• Oscillation of the mini vibration rod with a resonance frequency of approx. 460 Hz is stimulated by the electronic.
• As soon as the vibration rod has been covered by bulk solids, the oscillation will be damped.
• The electronic detects the damping and switches the relay signal.
• If the filling level sinks below the vibration rod, the rod starts vibrating with its resonance frequency again and the relay switches back.

Information for use
Please obey the following for the use of the Vibro level indicator:

• Switch point dependent of bulk density (t/m³; kg/l):
• with heavy bulk solids only the tip of the rod has to be covered for damping the vibration.
• with light bulk solids the complete rod has to be covered for damping the vibration.
• In order to keep the ambient temperature of the PCB below +60°C
• protect the housing from direct sunlight by installing a sun shield.
• protect the housing against temperature transfer from the silo in cases the process temperature exceeds 60°C by installation of a heat barrier between the enclosure and the bin wall or use the high temperature option E1.
• The measuring device must not be mounted in or near the filling
• The measuring device must not be mounted in or near the filling stream.
• The falling bulk solids could damage the probe.

Electrical data

• Wide range electronic C8
• Supply voltage 20 … 250 V AC / DC
• Power consumption € 3 VA / 3 W
• Signal relay potential free change-over-contact (SPDT)
• Capacity of contact 5 A / 250 V AC or 150 W at DC
• Connection clamps maximum 1.5 mm²

Technical data

Material

• Round-housing Aluminium coated, RAL7001
• Process connection and probe Stainless steel 1.4301 / 304
• Mini vibration rod Stainless steel 1.4301 / 304
• Suspension cable sheath Polyurethane
• Cable entry
• Type of protection Maintenance
• Maximum load for the end of the vibration rod
• Maximum tensile force at suspension cable of type VF65

 Versions/Dimensions

VF62 Compact sensor

VF63 Rod extension sensor VF65 Suspension cable sensor

High temperature up to 150 °C

 Possibilities for installation

Side mounting or vertical mounting

• VF62 and VF63 can be mounted either from the side or vertical.
• For side mounting it is recommended to screw the measuring device slightly downwards (approx. 20°) so that bulk solids can flow off.
• The measuring device has to be mounted in such a way that the filling stream cannot damage it.
• In case the filling stream reaches the probe nevertheless, it has to be protected by a suitable protection roof.
• If the probe is used as empty indicator in the lower area of bins/silos with heavy bulk solids, a protection roof has always to be installed.
• VF65 is suitable for top mounting only.
• A suitable sealing, (like Teflon tape), must be applied onto the thread and the VF has to be s crewed into the provided socket with a 36 mm open end wrench.

Protection against bulk solids crashing down upon the rod
Level indicators must not be affected by flying bulk goods particles e.g. from injection pies, filling pipes or down pipes. Therefore the bulk solids stream should be directed or redirected accordingly, or the level indicator should be placed so that bulk solids cannot impact directly onto the probe and vibration rod.

Flush installation

Protection against moisture by alignment of cable glands

The cable glands must always point downwards to prevent moisture seeping inside the housing. If the housing is not in the correct position after the probe has been firmly screwed into the bin wall, proceed as follows:

• remove the screw in the middle of the cover (4 mm Allen key) and open the housing.
• resolve t he spacer nut M6 in the center of the enclosure (10 mm wrench) a little bit until the enclosure is turnable.
• turn the housing into the correct position so that the cable glands are pointing downwards.
• tighten the spacer nut M6 again, torque 3 to 4 Nm.
• put on the housing cover and tighten the screw, torque 3 Nm.

Allowed temperatures

• Ambient temperature at the probe (process temperature)
• T(process) -20°C … +80°C
• Ambient temperature at the electronic housing
• Ta -20°C … (+50°C) +60°C
• Due to the process temperature of 80 °C reduced maximum allowed ambient temperature at the electronic housingMaximum allowed ambient temperature at the electronic housing is dependent of the process temperature.

Bulk solids temperatures up to 150 °C
The high temperature option E1 enables the use of the level indicators for bulk solids temperatures up to 150 °C.

• in order to protect the electronic against overheating by heat transfer from the process, a decoupling for high temperatur E1 is installed between probe and electronic housing.
• use for process temperatures above 80 °C only level indicators with the high temperature option E1.
• due to high process temperatures the maximum allowed ambient temperature at the electronic housing is reduced (see diagram)
• please mind for exchange of electronics that only PCBs with the marking „Special Model HT“ may be used.

Electrical connection Wide range electronic C8

Setting of sensitivity

• Adjustment by jumper at A – B – C Position A: highest sensitivity level for light bulk solids with a density above 0.02 kg/l
• Position B: standard sensitivity level (factory setting) sufficient for most bulk solids.
• Position C: lowest sensitivity level
• for heavy materials with high densities which may form a deposit on the vibrating rod.
• Light materials can not be detected at this setting!

Maintenance

The Vibro level indicators require no maintenance.

• For applications with materials that are a little bit sticky we recommend to clean the vibrating blade of the instrument in certain periods of time.
• If the instruments are exposed to corrosive atmosphere, they must be inspected in certain periods of time regarding corrosion of probe and enclosure in order to ensure the tightness of the instruments.

Disposal

• Level indicator VF can be recycled.
• Disposal of the VF is subject to the environmental legislation of the respective country in effect for the operator’s premises.

Returns

• Remove all adherent material residues of filling material from the measuring device. Be aware of seal grooves and cracks where material residues could stick.
• In particular if the bulk goods or liquids has been dangerous to health, e. g. flammable, toxic, caustic or cancer-producing.

Furthermore please state

• Chemical and physical characteristics of the bulk goods or liquid
• Description of the application
• Description of the failure occurred
• Operating time of the measuring device.

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