Positive displacement liquid flow meters are the most accurate volumetric measurement system for marine applications. Those highly accurate meters are suitable for a wide range of liquids from low-density LPG to viscous petrochemical products. This S-Keeper 7™ companion is a must-have for a real fuel consumption management to increase the ship efficiency.

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How do they work? Imagine to fill a glass by water flowing from your kitchen tap, as soon as it is totally filled you move it away and they you place another empty glass under the tap and so on…Knowing the volume of the glass and the quantity of glasses filled is enough to calculate the quantity of water just flowed. Increasing the process flow means only the glass exchanging is faster but the single glass volume is identical.

Simple. But not easy.

Manufacturing a purely mechanical device with no maintenance at all, with no drift, designed to last for 20 years and more it is not easy. Since 1938 VAF Instruments BV has dedicated its business only to design and manufacture the best solutions for an uncompromising excellence: quality with no frills at all only for demanding Customers. Hundreds of thousands of meters delivered in almost 80 years of production have given to VAF Instruments BV the opportunity to be the most preferred supplier of the top 100 shipyards and market leader in maritime measurement systems today.

VAF Instruments liquid flow meters are approved by 14 independent classification agencies, which is more than any other flow meter can boost on. VAF’s range of products covers flow rates from 1 liter/hour up to 960 m3/hour. Specific models are suitable for operating pressures up to 320 bar and a standard choice of high quality materials cover almost every service condition.

Unlike most flow meters, including Coriolis and other Positive Displacement flow meters, VAF Instruments liquid flow meters have a superior customized rangeability. They are not only accurate on a high flow rate, but keep their accuracy on the lowest rates. VAF Instruments liquid flow meters are all calibrated on <10%, 40% and 100% and any other flow rate that is required.

The VAF instruments portfolio encompasses several models each one designed to solve a specific application, here a short summary for an easy selection:


Pistons principle: the meter consists of four radial pistons, actuated in turn by the head pressure of the liquid. The pistons are linked to a crankshaft which is connected by a magnetic coupling to an LCD type rate-totaliser or to a mechanical totaliser with or without electric pulse transmitter.

Sliding vane principle: the meter consists of a specially shaped housing in which a rotor can rotate freely. Two pairs of vanes are placed into four slots in the rotor. Each pair is positioned by a rod and can move in and out of the rotor. The radial movement of the vanes is guided by the special inner shape of the housing. This patented construction provides a constant seal between the inlet and the outlet of the meter. The incoming liquid forces the rotor to rotate. The rotation of the rotor is transferred via a magnetic coupling to a read out device.

Also available VAF Instruments liquid filters/deaerators to be used in combination with VAF flowmeters. The use of liquid filters protects downstream equipment against abrasive particles and clogging. The sturdy, compact construction and the particularly large filtering area ensure that these liquid filters are on the ‘safe side’ even in tough and unfavorable conditions. The design permits trouble-free operation at all time and easy cleaning. The use of a deaerator tank is to prevent, especially at start up, large quantities of air or gas entering the process liquid.

Apart from the positive displacement flow meters TECNOVA HT also supplies a range of other types of flow meters such as turbine-, magnetic inductive-, Coriolis effect- and ultrasonic flow meters. Please contact us for more information on these products.