Alfons Haar

Taking control of fuel cocktails


We hope you had an opportunity to read our article in the RA 1st edition 2019. In this 2nd edition, we focus on curbing and preventing fuel cocktails and mixtures of auto fuels into target storage tanks.

Road fuel tankers fitted with meters can be classified into two types – “Wet” and “Dry” systems.

We hope you had an opportunity to read our article in the RA 1st edition 2019. In this 2nd edition, we focus on curbing and preventing fuel cocktails and mixtures of auto fuels into target storage tanks.

Simply explained “Wet” meters always retain a certain volume of liquid after completing a delivery. Whereas, “Dry” meters empty the contents completely.

Historically the fuel transport industry has used “wet” meters. Typically, vane or gear type in design.

Normally fuel tankers transporting petrol and diesel on the same load have two meters – One dedicated to petrol and the other for diesel for the obvious reason to keep the two products separate. Even then there is no guarantee that a product cross-over accident can be avoided. These dual systems are equipped with a multitude of valves which the vehicle operator needs to deal with, often with unfortunate mishaps.

Of late there are single “wet” meter systems on our roads, transporting Petrol and Diesel in the same tanker. The motive behind having only one meter in this case is purely cost saving (fair enough). However, the opinion or misconception out there, is that the residual amount of fuel left behind in the meter can be ignored. As bizarre as this sounds, it seems acceptable for some to deliver a different product on top of that left behind in the “wet” meter system.

How much is allowed?

Ask any Oil company to agree on an allowable % mixing of Petrol in Diesel or vice versa. The last official amount I managed to find was 0%.

Depending on the type of “wet” meter a left-over of 10-15Litres can remain. Then one needs to consider the product left behind in the pipelines, let’s say conservatively another 8-10lts. So, we now have about 20lts residual petrol or diesel left behind in such a system. Assuming a compartment load of about 6000Lts petrol. That equates 0,33% diesel into petrol. The problem becomes worse considering the opposite if you have residual petrol. Since diesel is heavier than petrol the same compartment loaded volume is now less at approx. 5300Lt = 0,377% petrol in diesel. And, a 0.1% contamination of petrol into diesel, lowers the flashpoint of the product by 3degC. Diesel into petrol lowers the octane rating – Get the picture?

Off-spec fuel with these types of systems is thus a reality.

However, the real issue lies when the fuel transporter has partly loaded volumes or leftovers, which are a normal occurrence.

A gravity delivery is normally 1000Lts minimum allowed……we are now 2% mixed. A pumped delivery can be lower – For 500Lts Diesel pumped over 20Lts Petrol residual, you will have a whopping 4% mixture.

The point is, there is no way to control the percentage mix in these single “wet” meter systems, unless additional complex and costly draining systems are installed. The above analyses assumes only the minimum product leftover. Nothing prevents higher volumes of leftover in such systems, since it requires the operator to ensure full drainage. Do they even know the residual volume leftover to make a responsible decision? – I doubt.

Enter PreciPURE, TURBINE metering system

– The TURBINE is a “dry” meter, thus emptying itself completely before a changeover of product type is started. This design provides the benefit of having only one meter installed instead of two as commonly used. Now with only one meter, the system becomes lighter, simpler and lower on maintenance and ownership costs.

PreciPURE takes care of the “cocktail problem”. It provides a complete solution to metering and fuel handling with a level of automation included. By its design, the PreciPURE system takes care of many of the functions and decisions the fuel truck vehicle operator normally must deal with.

All operations and system functions are handled via a single human interface, called the CountMASTER. The CountMASTER is an electronic register through which the operator loads and unloads the bulk tank vehicle. No additional buttons or levers are needed while operating a PreciPURE, leaving the operator safely focused on the task at hand.

PreciPURE is equipped with a hydraulically driven pump and can thus take care of gravity as well as pumped deliveries of fuels to site.

Additional optional features available include;

  • Security sealing of loading points and access manlids.
  • “Retained Product Monitoring System / RPMS” – RPMS checks for any left on board inside the compartment before loading. The first step in preventing mixtures.
  • Engine management system control – Reducing truck idling times, Lowering fuel emissions and fuel costs.

Bernard Burgess,

Managing Director – Alfons Haar South Africa

(T) 021 945 1191

comments powered by Disqus


This edition

Issue 70


RoadAhead_Mag Automation with the help of advanced technology and a growing demand for lower costs typically associated with proc… 4 months - reply - retweet - favorite

RoadAhead_Mag In this edition of The Road Ahead Magazine, the editor speaks about effective #Leadership and the #Springboks. Rea… 5 months - reply - retweet - favorite

RoadAhead_Mag #UDTrucksSA has introduced its high-level technology All-New Quon extra heavy range. This includes four 6x4 rigid m… 5 months - reply - retweet - favorite