An opening for more side-load reefers
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Operators who want refrigerated trailers with curtainsiders need to look around. Bill Brock has been helping them do it and has come up with three names
COMPLETE side access over the length of the platform for enclosed dry-freight body types has been readily available in one form or another on both rigid and semi-trailer chassis for a long time.
With a wider need for temperature controlled vehicles, which in more recent times may be used to carry anything from computer parts to tomatoes, the same degree of speedy accessibility is, for some operators, now a desirable feature. However its not usually available on conventional reefer-bodied vehicles.
In order to find out what the industry has to offer I contacted six trailer manufacturers. The two best known names in the business, Crane Fruehauf and York, confessed that they are not into the side-access, insulatedbody field. When I tried to contact Bona!lack at Norwich, which is known to specialise in conventional insulated and refrigerated vehicles, I was told that the staff were on holiday.
My list was rapidly depleting, but the next three contacts, with Craven Tasker, Boalloy and Lawrence David, bore fruit in the form of three variations on the same theme.
The Tautliner from Boalloy set the pattern for curtainsided vehicles built to carry dry freight and the company was again well ahead of the opposition when in 1978 it introduced its lnsuliner. It is now much improved.
Polyurethane roof insulation has been increased in depth from 38mrn (1.5in) to 101mm (4in) and a refrigeration unit has been added to the front, normally insulated, bulk-head. The rear doors are now 76mm (3in) thick.
Specification can be flexible but it cannot be denied that inclusion of floor insulation also improves performance considerably.
However, the key to the lnsu liner's thermal performance is said to lay in the patented, quilted side-curtain material containing a spongy filling made up of thousands of tiny air bubbles. Vertical pockets located at 508mm (20in) centres house the tensioning straps attached to stainless steel buckles; steel side-pillars are boxed in with grp, so reducing the effect of an otherwise obvious heat path.
Special pelmets and floor seals enable this design to operate at internal temperatures of between —8 and 5°C. An lnsuliner can be as much as one ton lighter than a comparable conventional reefer. ATP approval has not yet been obtained as its terms of reference relate to a rigid construction, but Boalloy will resubmit its vehicle if the wording of the specification can be changed.
In contrast to the end to end opening of the Boalloy curtain sider, Lawrence David employs a full-length, lift-up insulated
curtain. Tests have shown that ii is possible to maintain tempera. ture differences by as much as 35°C. In practical terms it should be possible to maintain goods al freezing point while the outside ambient temperature is about normal.
As with its dry freight, Rollersider counterpart, the curtain is lifted to roof level, allowing clear unobstructed loading over the full length of the body. The curtains are raised by an electric motor, remote controlled by push buttons on the front bulkhead.
The insulated version is constructed from a double layer of polyester fabric impregnated with wear resistant pvc on both sides of a 12mm (0.471n) flexible polyurethane foam sandwich.
Thermal seals at the base of the curtain incorporate double rubber-sealing strips located in an aluminium-alloy extrusion fitted to the side rave. At both end pillars, the curtain butts against a fine brush seal verlapped on the outside by a axible plastic sealing strip.
Along the top ledge, boarded ibric looped to the inner edge f the roof rail and plastic seal bolted to the roof rail, elimiates heat losses over the top of le curtain.
Sealing at the perimeter is assted by vertical tension. This in be improved by winding the irtain against the full-length tuular bar suspended from the ase.
Typically, a 12m (40ft) trailer ill include 15cm (6in) of insulaDin in the bulkhead, 10cm (4in) the roof and 7.5cm (3in) in the Dors. These measurements can a altered to match requirelents. The bulkhead is framed I steel, has an aluminium-alloy uter skin and a plastic-faced lywood lining covering the inilation. The doors have double ibber-seals with a special P)ction design on the inner Jge.
Craven Tasker's Taskload ailers, designed with side-slidig doors to meet EEC requiretents for carrying food, can be Jpplied in three versions: insulted, refrigerated and dry eight.
The advantages of three-way 7;cess are common to all, allowig considerable delivery flexiility.
The sliding doors along each de are hinged outward on top fliers to clear each other, while t their bottom edge there is no ottom guide rail. A single lockig bar with fully retracting lamping cams provides posiye location when closed and istant unobstructed access at
floor level behind any of the individual panels when released.
Doors, extending from the floor to roof, can include various degrees of insulation — from chilled to frozen conditions. Maximum thickness would not normally exceed 76mm (3in).
Craven Tasker's recent development in its refrigerated and insulated range has been with the Super Taskload; this is a response to a demand for increased internal width. Because the doors overlap, the maximum usable internal width is measured between the two innermost doors.
Within the maximum permitted overall width of 2.5m (8ft 2.51n) Craven Tasker now claims to be able to provide an internal working width of over 2.43m (8ft), enough to accommodate two metric pallets side by side. Built to meet DoE recommended levels of load restraint, the doors will withstand more than half of the weight of the payload. A front bulkhead with up to 100mm (4in) of insulation is at least twice as strong and well able to support the additional weights imposed by a freezer unit.
The roof, incorporating composite roof rails, employs a onepiece aluminium roof panel and up to 152mm (6in) of insulation materials. Various floor constructions can be selected from softwood, plywood, composite with aluminium, or treadplate overlay and specified with a maximum of 127mm (5in) of insulation.
Boalloy, Lawrence David, and Craven Tasker all offer internal load-restraint systems if required.
Each of their systems is able to maximise on accessibility, payload and internal volume, but falls short of ATP specifications required for international transport.
However, for a wide range of food products the level of temperature control they provide will meet with approval from UK customers who increasingly demand delivery of produce in as fresh a condition as it left the farm. But it should be said that none of these body systems yet meets the level of temperature control available with the fully fledged reefer body.