PRESSING DOWN ON A WEIGHTY PROBLEM
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• It takes a brave transport manager to develop a special vehicle for his fleet. The costs can be immense, and the potential for mishap can be enormous.
If you get it right, however, and come up with a vehicle which suits your needs far better than anything available on the market, the savings can be tremendous.
David Round, British Vitas fleet engineer, began developing a special trailer for moving the company's foam products in November 1986.
He travelled to the Netherlands to see operators using trailers with moveable roofs that can be lowered to compress large volumes of foam.
When he returned to Britain, Round found few British trailer manufacturers were interested in developing a similar vehicle suited to British Vita's needs. "We talked to a whole number of companies," he says, "but very few were prepared to carry it through."
Eventually, Round chose Carrymaster for the work. There began six months of intense development involving several radical changes from the original design.
"We tried two different types of hydraulic ram," he says, "and I decided that the roof needed to be specially strengthened. With a conventional roof we experienced problems with bowing, so we beefed it up and lined it with plywood."
There was close co-operation between Carrymaster and Round to ensure the vehicle met British Vita's requirements precisely.
"It is unique in the sense that it is a trailer with a curtainsided body," says Round. "On the Continent they use van bodies which tend to have smaller dimensions. We have opted for the maximum aperture, because, when compressed, foam behaves like a concertina — it doesn't splay out. The trailer is certainly unique in this country."
The roof is raised and lowered by hydraulic rams. "We use both AC and DC supplies," says Round. "When loading the vehicle we can take AC power from the loading bay, and at the destination we use DC power from the battery to raise and lower the roof. There are extra batteries on the vehicle and they are on trickle charge during each journey."
Unlike those trailers operating on the Continent, the Carrymaster trailer's lifting rams work together to ensure that the roof is raised and lowered evenly.
"The main motor works to a valve block," says Round, "which provides power to each of the rams independently. It's rather like Hydragas suspension — the rams work to compensate each other. If the foam blocks in the trailer are uneven, the system will divert power to ensure the load is compressed properly."
The major benefit for British Vita of using a compression trailer is increased carrying capacity. "With a compression trailer we can carry more than four tonne of foam when fully laden, whereas a conventional trailer will carry between oneand-a-half and two tonnes.
"The problem with foam blocks," he adds, "is that they have different densities. If you look at standard blocks, we can get 16 on a conventional trailer, and 27 on the compression trailer. Customers usually want a mix of products, and that way you can get up to 35 blocks on the compression trailer. To move that many we might have had to use two-and-a-half conventional trailers."
WHY NO DRAWBARS?
Given the volume benefits of the compression trailers, why didn't Round go for drawbars? "We looked at drawbars but rejected them on several counts. We try to load as many foam blocks in as short a time as possible, and we are based in a mill designed for cotton production. We have loaded a continental drawbar with a compression roof here, but we found that very difficult physically because there wa; insufficient space. When you get out to some of our outstations you need very tight turning circles," As it is, the compression trailer allows British Vita to squeeze up to 126m3 of foam in a space which normally takes 42m3 of foam. "The compression trailer has not helped us reduce our fleet," says Round, "though it may have knocked out a sub-contractor — we're moving twice what we can do conventionally."
The trailer's development costs have been written off as a one-off expenditure, says Round. To buy the compression trail er now would cost around 227,300, compared with between 211,500 and 212,000 for a conventional trailer. Round estimate that the compression trailer produces say ings of around .2135 per trip.
At an average of four trips per week, he calculates the compression trailer produces savings of around £24,600 a year. In other words, for British Vita's operations, the trailer pays for itself (though not for its development costs) in around 117 trips, or 30 weeks.
"I'm sure we will go for more of these compression trailers," says Round, whose British Vita foam fleet currently consists of 20 tractors and 50 trailers. "The compression trailer has been eating into the work of our sub contractors a little bit and that has been very beneficial for us."
The trailer has also provided unforeseen benefits.
"Our drivers prefer the compression trailer because it is more stable than our conventional trailers, particularly in high winds," says Round. "It's 16 feet (5m) high with a tandem axle — we normally use single axles but on the compression trailer we wanted stability. That was the prime thing, but it also allows us to carry heavier loads on return journeys."
Now the compression trailer is used not only for carrying foam for British Vita, but also for carrying return loads of polystyrene for sister company Kay Metzeler.
British Vita has been operating the compression trailer since 10 August last year, long enough to highlight any major problems with the design_ There have been few problems; indeed, according to Round, "It performs very well."
Drivers not only prefer the trailer's stability, they also like its ease of loading, states Round. "On the continental compression trailers, the rams don't work in unison, so they have to mess about a bit more," he says. "Our drivers have needed no special training in loading. One man with a forklift truck can load the trailer and it is becoming a very slick operation. It does take longer to load the compression trailer, but then it carries more."
SCANIA ON ORDER
Mercedes-Benz tractors predominate in the British Vita fleet and to haul the compression trailer Round has opted for a 1625, down plated to 28 tonnes. With the increased capital cost of the towed vehicle, Round is looking for operational savings from his tractor fleet. To that end he has ordered a Scania 93 which he hopes will provide a comparison on fuel.
Developing a new trailer for the fleet has had important implications for British Vita's operations. Thorough development work has ensured that the design works properly, and is providing tremendous operational savings for the company.
Round takes the credit for having the vision to try something new, and Carrymaster deserves mention for accepting the development work when other trailer companies were not prepared to get their fingers burnt. Both Carrymaster and British Vita look set to benefit from the success of the development. Nothing ventured, nothing gained. . .