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What is Float And Board-Level Gauge | Benefits of Level Gauge

Float And Board-Level Gauge

FIDICON is a pioneer in the field of manufacturing Float and board level gauge (Model NO. FDI-FBLI-401) in India since 2002 years of designing, manufacturing, installation and service of the same. Level gauge manufactured by FIDICON are user friendly and easy to install. It comes in many ranges and can be tailor made as per the requirements of customers. 


Float and board level gauge/indicator 

For the measurement of level of fluids at various industrial applications level indicators are used. These devices are used to determine the level of liquid in tanks, drums. Pressure vessels etc. 


For needs of different applications there are many level indicators to suit the purpose. In highly commercial industries normally, fluids are used in many forms. In absence of proper devices, it will be very difficult to find the quantity and level of fluid stored in a vessel/container etc. In many situations where the nature of fluid is dangerous or sometimes the place it is manually impossible to find the level in which the liquid is stored because the nature of the material, then the level indicators are of utmost importance. 


Level indicators should be selected depending on the type of application used e.g., in the process industry, tubular level indicators are used for better visual liquid level indication. If it is for non-contact type level measurement, then radar type indicators or ultrasonic type indicators are to be used.


Industrial needs:

1) Chemical industries

2) Petrochemicals

3) Fertilizers &;

4) Pharmaceuticals, etc


Industrial application:

To Measure Level in


1) Drums

2) Tanks

3) Pressure vessels

4) Boilers, etc


Types of level measuring instrument:


1) Side Mounted Heavy Duty Tubular Level Indicator

2) Reflex Level Gauge

3) Float and Board Type Level Indicator

4) Float and Board Type Magnetic Level Indicator (Vapor seal Type)

5) Side Mounted Magnetic Level Indicator

6) Top Mounted Level Indicator

7) Top Mounted Magnetic Level Indicator

8) Side Mounted Magnetic Level Indicator with Transmitter

9) Top Mounted Magnetic Level Indicator with Transmitter

10) Displacer level switch

11) Capacitance level indicator switch

12) Fork type level switch

13) Side Mounted Magnetic Level Indicator with Transmitter

14) Top Mounted Magnetic Level Indicator with Transmitter


And many more….


Float and board type level gauge :

This type of float & Board type level gauge/indicator basically works on the principle of buoyancy. The float is well connected to the counterweight along with a pointer through flexible wire ropes. The pointer slides along the guide against a graduated scale to indicate corresponding levels inside the tank.


What is Float and board level gauge?

Float &; Board is a type of level gauges &; is a weighing liquid level measuring system finds it’s application for non-pressurized storage tanks &; vessels. It is actually a balanced counterweight system with an arrow-shaped pointer which eases the indication process.


Working principle of Float and board level gauge


1-The working principle of Float &; Board level indicator is based on the buoyancy principle (Archimedes’ Principle) and is linked as per balanced counter weight system.


2-Float inside the tank and counter weight (scale pointer) connected by the rope wire which moves freely on the pulley assembly indicating the height.


3-When the storage tank is empty, the float will be located inside the bottom most part of the tank &; the scale pointer located at zero level on external scale.

4-When the liquid level rises in the tank, the float moves upward and scale pointer moves downward on the graduated scale to show liquid level inside the storage tank.


5-In case of turbulence in tank liquid level use of float guide rope wire assembly with anchor for stability of float is recommended.


6-Float &; board level gauge is a simple in construction &; economical level measuring instrument. It consists of scale board, pointer, pulley, pulley housing, connection pipe, wire rope, float, guiding flanges, process flanges &; anchor plate.


7-Top &; side mounting brackets are provided to mount the scale board outside of the tank. Connection pipe, pulley, guiding flanges are mounted on the top of the tank. 


8-Scale board is also mounted on the side of the tank. Anchor plate is fitted on the bottom of the tank. Float is set to float on the liquid level surface.


9-Float and board level indicator is attached to a multi stand wire rope, which passes through Friction less specially designed pulleys.


10-The pulleys in turn are connected to a pointer, which moves on a graduated scale by the side of the tank.


What special :

Most of the times, the float & board type level indicator has dust proof pulley housing. It comes with a bush bearing for a smooth rotation of pulley.


The pointer has rollers and adjustable brackets for easy mounting. It has a non-corroding board with controlled cross section geometry and a wide painted scale with prominent multi colour marking. The indicator has a slack float with large diameter for higher accuracy. This level indicator is very easy for transportation & installation.


Design and standards:

Designed in accordance with ANSI, DIN, JIS, ISO and various other international standards


Testing of level gauge


1.) Flange dimension check

2.) Scale verification


For more brief procedure, kindly contact our QC team

Email us : qc@fidicondevices.com

Contact us: +91 6358970219


Application / Benefits of Level Gauge :

  • Even with large changes in liquid density, the immersion of a large diameter float will change very little, thus density has little effect on accuracy.
  • Float systems are simple and easy to understand.
  • Even if the primary requirement is the transmitted signal, local indicators can continue to operate, even on loss of power.


The industry we serve :


1) Chemical, petrochemical industry, Refineries

2) Pharmaceutical industry

3) Marine industry

4) Water & wastewater treatment plants

5) Pressure vessels, Storage tanks

6) Others


Features :


1) Simple

2) Easy Mounting

3) Low Maintenance

4) Economical Measurement Solution

5) Assured Level Indication without power supply


Float and board level gauge installation :



  • Ensure that all the components of gauge are received in good condition.
  • Ensure wire rope received is of required measuring range.


Precautions for Float and board level gauge Installation:

  • During installation, tank should be in totally empty condition
  • Selection of Location
  1. a) There should be no objects which shall hinder the float.
  2. b) Ensure that the float position inside the tank should be such that agitation on it will be


  1. c) The position of the mounting nozzle should be far away from the liquid filling pipe to protect the float from damage and faulty readings due to turbulence.
  2. d) Ensure that tank structures/fittings do not come in the way of calibrated gauges boards.

Instruments required- Welding machine, combination/crimping plier, 10/11 spanner, and adjustable.


Guided Construction x Ground Level Tank


Welding operation on Tank


  • Welding of Nozzles – Locate position of the measuring nozzle at least 500 mm from the tank inner wall maintaining 650 mm distance from center of measuring nozzle to gauge board. Ensure that there is a clearance of min 100 mm between the float & other internal parts.
  • position of guide nozzles and distance between them is maintained according to float size.
  • Bore appropriate holes at located positions and weld the nozzles on to the holes in an upright position.
  • Welding of Conduit Support – weld `conduit support' on tank top and ensure that it is parallel to the gauge.
  • Welding of Gauge Bracket Supports– They are welded on side of the tank wall for mounting the gauge boards.
  • In case of tank in service or plastic tanks, construct a support structure or a pole should be grouted along the side of the tank wall and weld these bracket support on it.
  • Start welding the gauge support from the tank top.


Mounting of Gauge Board

  • Gauge boards are supplied in 1 meter long with graduations on its front side.
  • The number of gauge boards are supplied according to measuring range and they have to be assembled at site and mounted with graduations in descending order (i.e., `Zero' graduation on board at the top).
  • Slide the bracket on the gauge board from its rear side and fix it on the holes provided on it with nuts and bolts and connect all the gauge boards to each other.
  • Now hold the gauge board assembly vertical so that zero graduation on the gauge board is at top and attach the gauge board to gauge support with nuts and bolts.
  • In case the switches are provided, fix the switch bracket on the rear side of the respective gauge board where the switching is required.

Fitting of Protection Conduit

  • Mount protection conduit and pulley assembly on measuring nozzle.
  • Fix process connection on measuring nozzle of the tank.
  • Attach vertical limb of pulley assembly to conduit support with ‘U’ bolt.
  • Ensure that the centre of vertical protection conduit and pointer are in line, so that float wire remains in plumb and does not brush with gauge board surface.


Measuring Rope Fitting

  • For guided construction, 3 no of wire ropes are supplied according to measuring range. Take measuring wire rope, open both the pulley enclosure covers and insert measuring wire rope through the pulley enclosure on process connection side. Unfold the measuring rope carefully to avoid any loops / kinks. Insert it through a vertical limb of protection conduit and it is then tied to the float bush inside the tank.
  • Pass the other end of float wire rope through horizontal protection conduit over the second pulley and vertical protection conduit.
  • Now check for smooth movement of the wire rope on both the pulleys by moving it in & out.
  • This end of wire rope is to be connected to pointer, the excess rope should be coiled and kept well clear of gauge board and should not obstruct the movement of pointer.
  • Slide the pointer on gauge board.


Guide Ropes

  • Now take guide wire, tie one end of it to the spring tension rod.
  • Unfold the rope carefully to avoid kinks or loops and pass the end of guide rope inside the tank through guide nozzle.
  • Tie one end of the guide rope to the spring tension rod.
  • Bolt the tensioner flange on guide nozzle flange.
  • Repeat this procedure for other guide rope.
  • Go inside the tank from the manhole, remove the twist in the wires.
  • Now insert the guide rope through the rope guides on the float.
  • Fix this free end of guide wire ropes to a knob on the weld able anchor plate or weighted anchor pipe with fastener.
  • Also fix up the measuring rope to float knob.
  • Hold the anchor on a support below it. (Take a brick wooden log of 50 mm height as support). Locate the position of bottom anchor plate by lowering a plumb line through the guide nozzles.
  • Check all three wires are parallel. Remove spring housing and tighten the tension adjuster nut to provide adequate tension to guide ropes and refit the spring housing.
  • Remove the support and weld anchor plate to tank bottom in metal tanks. However, for nonmetal tanks or tanks in service, the guide ropes can be weighed down by the anchor pipe filled with sand.
  • Ensure that pointer is at top and reads `Zero', when float is resting on bottom anchor.
  • The equipment is now ready for use.


Read Also: What Are The Types Of Level Gauges And Their Applications?


Taking Gauge into Operation

  • Pull the pointer manually downward over the gauge board till it reaches its bottom end to ensure that the float lifts upward to the tank top freely. Now raise the pointer slowly and ensure the float moves downwards freely.

Do not remove your hold from the wire rope otherwise the float will get damaged.


  • Fill the tank with liquid, check the reading on gauge board and compare the same with the dip measurement. In case of large error, adjust the level indicating pointer accordingly.



Correct installation of all mounting accessories on the tank is very important for accurate indication of level.


Unguided Construction x Ground Level Tank

In this construction guide ropes, tensioner and anchor plate are not supplied. However, installation of unguided construction is similar to guided construction. Hence follow the instructions mentioned above.


Guided Construction x Elevated (Overhead) Tank

In this case, the gauge board is mounted either on 1) side of the tank wall, or 2) at ground level, below the elevated tank.


  • If the mounting of the gauge board is on side of the tank wall, follow the same installation instructions mentioned in guided construction x ground level tank.
  • For gauge board mounting below elevated tank.
  • Measuring wire rope is supplied considering elevated height of the tank.
  • Fix conduit support on side wall of the tank and gauge board support on column support of the tank.
  • If the tank column supports are not in line with tank side wall, then erect a grouted pole of suitable length on the ground such that it comes in line with tank side wall and fix gauge support on the pole.
  • Fix extended protection conduit on conduit support and gauge board on the gauge support.
  • For remaining installation follow the steps mentioned in Guided Construction x Ground Level Tank.


Underground Tank x Half Pointer Travel

  • Level gauge is supplied with full travel up to 4 meters range for underground tanks. For range between 4 to 8 meters it is supplied with half travel.
  • Installation of FBG with half pointer travel.
  • Erect the grouted pole of suitable length on the ground for mounting of scale board
  • Measuring rope supplied is of suitable length for the given measuring range. Guide wire rope lengths are according to measuring range. Gauge board supplied is suitable for half travel with LC of 10 mm and pointer is attached with pulley Follow all the instructions as mentioned in 4.1 for guided constructions.
  • Weld M16 bolt/screw on the gauge board at top.
  • One end of measuring wire rope is connected to float knob inside the tank and other free end is inserted through conduit pipe (vertical limb). It then is then passed over the pulley attached to the pointer and then hang it on bolt.


Pointer with Pull Chain is provided optionally for highly viscous liquids which tend to solidify at

ambient temperature. It consists of nylon rope with PP handle. It used to take out the float during maintenance. It also facilitates periodic testing of float for correct position.


Recommended Services/Maintenance for Float and board level gauge

  • Periodic inspection is necessary to keep your gauge/Level Indicator in good working condition.
  • Wipe the float to remove sediments particles and visually examine for any damages.
  • After maintenance, ensure that switch (If applicable) enclosure cover is fitted with its gasket for ‘IP66’ weather proofness.
  • After detaching measuring rope from elbow pulley, check movement of pulley by removing pulley cover and ensure that it rotates smoothly around its shaft. Check for wear & tear and clean the pulleys if necessary.


Recommended Spares for float and board level gauge :


1) Float

2) Pulleys

3) Wire/Rope

4) Pointer

5) Anchor Plate


Recommended disposal for Float and board level gauge :

  • Give it back to us & we will take care of recycling & possible disposal.
  • User can dis-assemble the product in multiple stages
  • 1-Metals / alloys
  • 2-PTFE/Polymer etc.
  • 3-Any other.
  • The above may be handed over (state pollution board), authorized re-cycler item-wise.


Notice :

1-The given content on this manual could be changed any time without prior notice.

2-All the rights reserved by FDIPL (Fidicon Devices India Pvt. Ltd) only. Reproduction, transmission of this documents in any form or by any means without the written permission of

FDIPL is prohibited.

3-The written content on this manual neither does decree the marketability of this instrument nor it does warrant that the particular instrument will comply the purpose of user.


Fidicon Devices is the lead manufacturer of Float And Board-Level Gauge contact us now for more detailed information about the products.