OPPORNUN ITI ES FOR INNOVATORS
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There is no such thing as a standard, general-purpose tanker — which leaves manufacturers and operators free to decide on ther own specifications, materials and equipment
• The range and opportunity for innovation in tanker design and construction is wide, providing for rigid and semi-trailer operation from 3.5 to 38 tonnes gross to carry materials as diverse as water, acids, petrol, hot bitumen, powder and food products.
There are about 20 tanker builders in the UK and competition is healthy which, in the long term, may be the industry's salvation, as there is a great deal of interest being generated by firms such as LAG, Hobur, Van fool, Magyar and Trailor, located on the other side of the Channel.
In the general purpose market Britain's largest trailer manufacturer, Crane Fruehauf, is geared up to match large production runs of the continentals.
Smaller companies, too, are able to compete on equal footing satisfying customer demand for the non-standard tanker.
There are many shapes and sizes in more specialised application, and even if they look the same they may be constructed from one or other of the various materials such as stainless steel, aluminium, mild steel or even FRP (fibre reinforced plastic).
A good idea is not necessarily a passport to success as demonstrated by Holiming Oy a Finnish company. Back in 1982 it produced a rigid tanker vehicle of monocoque construction with a 6 x 2 axle arrangement for operation at 22 tonnes. It offered an excellent kerb weight of only 7.5 tonnes, complete with 300kg of discharge equipment, ready for the road. The 4.2min aluminium tank served as the backbone of the vehicle onto which cab, engine, transmission, axles and ancilliary equipment was attached.
Compact air bags were used to suspend both front and rear axles giving the option of a lifting tag axle at the rear but more importantly allowing a low C of G at about 400mm lower than that of a similar vehicle with a chassis.
Lack of fire shielding around the engine prevented it from complying with UK Petroleum Regulations, but we know that about 50 vehicles were in service with major oil companies in Finland before the company ceased to trade the following year.
M and G's FRP tanker developed and improved since 1975 is, however, still enjoying only a limited success. Since the design was changed, 18 months ago, to cater for 38 tonne operation, the company has sold 33 trailer tankers to major oil companies. The initial purpose of this revolutionary design was to combine a high payload with increased impact protection, while carrying white spirit.
In the US, Mobil Oil has found a use for the FRP tanker in transporting lubricating oil. The closed mould construction, comprising an outer skin and inner cells of FRP, separated by a core of flame retardant polyurethane foam, insulates and maintains the product at a temperature of about 80°C.
M and G claims to be the first compair in the UK to have carried out a conversion to bottom loading and vapour recovery.
Crane Fruehauf, through Fruehauf of America, has been discussing its introduction since 1980. Because of higher Lbient temperatures in the States, Lich result in vapour problems, it has en standard on American tanker ilers since the early 1950s.
Bottom loading enables the driver to erate at ground level and vapour revery gives benefits in safety, is better vironmentally and provides a return for ! oil company.
Over the next few years the oil indus, is committed to introduce bottom ding at new and existing terminals. Strategically placed vapour recovery Eves, air-operated cut-off buttoms and interlock bar over the bottom loading Eves ensure that all the fuel is conned within the system and prevents .t vehicle being driven away.
The 38 tonne M and G tanker weighs Dut 5450kg ready for the road, but fol. ving a current weight reducing exere its unladen weight may be reduced 5250kg.
The design is competitive on cost with ilt trailers built from aluminium but both Id steel and stainless steel are s,•aper. They cannot match the FRP liter's payload.
Using a similar double wall construcn, M and G also build tanks of up to e compartments on 24.38 tonne rigid assis.
Pearce and Wright Engineers, a Liverol-based company, has produced all sses of bulk liquid tankers for about 15 ars. It has developed a very light [Hess steel tank trailer with a 30,000 e capacity for operation at 38 tonnes, lich approaches the M and G tanker's 3tweight. It is a general-purpose Liter, built on the stainless steel ring nciple, providing a tare weight of i00kg which includes side guards, :-.ess ladders, hose troughs, chassistinted rear underrun bumpers, and ackets.
More than 65% of the tankers in use tre built to carry bulk liquid of one type another.
As protection against some of the )re corrosive elements of some cares the tanks can be lined with glass, ter or some form of epoxy resin. P and W's general purpose tanks are
of cylindrical section, with an internal diameter of 1905mm. With up to seven outer rings over its length it is self-supporting so that it can be mounted with its belly close to the axles, to bring the height of the C of G as low as possible.
While tanks do not need to conform to Type Approval as such, there are various codes of practice and standards of construction. Statutory instrument 1059 relates to the carriage of hazardous substances: ADR is the international agreement on the carriage of dangerous goods and the IMO certificate, obtained Only after independent inspection throughout the build, will allow the container to be used to carry hazardous loads on board ship.
Tanks can last as long as 20 years or more outliving their original running gear and chassis several times, so inevitably a major part of the tank manufacturers' activities is devoted to repairs, reburbishment and upgrading tanks to match the changes in regulations.