The new MTK tank container plant in Sunderland, England, demonstrates the efficiencies possible when concentrating on only two product lines. The $18-million plant will produce 20-ft framed beam tank containers for international shipping and 25-ft swap body tanks (domestic containers) for the European market.

The initial plan had been to build only 20-ft ISO IMO-1 tanks in large-volume orders, but the longer swap tanks were added because of the growth in the market of these popular, non-ISO tanks. These larger tanks are built in three of the most popular swap body lengths, with frames set at 7.15 meters (231/2 feet), 7.45 meters (241/2 feet), and 7.82 meters (25' 8"), and the tanks extend beyond the frame. Capacities range up to 35,000 liters (9,250 gallons).

The proven designs of both the ISO tanks and the swap tanks are licensed from Westerwalder Eisenwerk GmbH of Weitefeld, Germany. WEW is continuing to build specialized tanks and to fill orders for small numbers of tanks, but has licensed MTK Containers to build the large orders. The two companies work closely together to develop joint markets.

Shipbuilding Center The site of the newly built plant on the northeastern coast of England some 70 miles from Scotland is an advantage, says Peter Hughes, sales director. It is located on the River Wear, with Port of Tyne on one side and Tees Port on the other, both giving excellent access to continental Europe. These three harbors also have good highway and rail links to the rest of the UK. Most of the MTK containers are shipped by water, either loaded from the big chemical plants at Teeside or empty to Rotterdam across the English Channel.

Sunderland is an old shipbuilding center with an active metalworking industry and many skilled workers. The shipbuilding industry closed down in the 1980s, leaving high unemployment and fewer job opportunities in its wake. Government incentives played a part in MTK's choice of the site, and so did the highly trained workforce. Most component suppliers are within 100 miles of the MTK plant and can respond quickly. This makes it easier to operate on a just-in-time basis and to guarantee delivery of containers on a precise date.

Production of tank containers in the new building is on a flow-line basis. Maximum flexibility is built into the layout so that changes and special equipment mounting do not present a problem. Customers can make changes to certain specifications as late as seven days before the delivery date.

Build time is minimized by automatic processes and advanced technology such as real-time X-ray of welds. By computerizing the X-ray machine, 100% of the circumferential welds and a portion of the other tank welds can be X-rayed, producing an immediate verification of weld quality as well as a permanent record without waiting for film development. Certification inspectors are on the line so that each container can be fully certified and documented by the time it reaches the end of the line.

The plant's production line can build concurrently 20-ft ISO tank containers and the longer swap body tanks. The production flow line is divided into five zones: (1) rolling the steel, welding the barrel with dished heads, and X-raying the completed tank; (2) making all attachments to the barrel; (3) attaching the tank to the container frame; (4) performing water and air tests, shot-blasting, pickling, passivating and sealing the tank, followed by painting of the frame; and (5) insulating and cladding the tank and adding walkways, decals, remote control devices, and data plates. A full inspection is performed before the tank leaves each zone. After final inspection, the container is fully certified.

Precision Engineered Fit Production Director Ron Deakin says that when welding the barrel, the engineering trick is to be as simple as possible on the production floor by doing the precision engineering on paper and calculating cuts for a good fit on the line. Sheets are sheared by a laser-guided cutter. Matched pairs of dished heads are accurate to within plus-or-minus 0.3 mm of the 7500 mm (about 241/2 feet) circumference of the tank. Close tolerance provides the good fit necessary for plasma TIG welding.

The plasma TIG welding is automatic using pure argon as a backing purge. Each 20-ft ISO tank has about 75 linear feet of plasma TIG welding. Because of the precisely engineered fit of the shell-to-head joint, Deakin says the rejection rate is less than one percent.

Welding of manways, fittings, and container frames, on the other hand, employs MIG welding using a CO2 and argon blend as the shielding gas.

Pressure Testing, Calibration After the tank and container frame have been assembled and fully inspected, the tank is pressure-tested and calibrated. This is a single operation, as the weight gain after filling the tank with water for pressure testing indicates the interior capacity. The 20-ft ISO tanks are designed for 4-bar (58 psi) service and are tested hydrostatically at 6-bar (87 psi). The 25-ft swap tanks are designed for 3-bar (43 psi) service and are tested at 4.5 bar (65 psi).

The typical ISO IMO Type 1 full-frame tank container has a tare weight of 3700 kg (8,140 lb) to 3,850 kg (8,500 lb) depending on tank capacity. The current range extends to 25,000 liters (6,600 gal).

The calibrated and pressure-tested container moves to the degreasing station and the pickling station, both computer controlled. Next is an enclosed chamber where the end frames are grit-blasted with aluminum oxide granules to prevent contamination and then primed. Final painting of the end frames is in a subsequent station. The tank is also passivated and rinsed, then blasted with hot air. At this point the tank is clean and completely dried.

The clean tank is completed under a plastic tent over the workstation to keep out any dust. Fittings are added and the tank is pressurized to one bar (15 psi) to test for any leaks around the fittings.After passing the air pressure test, the tank is sealed to prevent any air contamination. The tank is ready for immediate use on delivery with no extra cleaning required.

Certified on Assembly Line Full-time inspectors for Bureau Veritas are on line during both shifts so that the tank is fully certified by the time it is sealed. Documentation is ready by the time the tank is shipped. Certification also is available in electronic format, CD or EDI.

Insulating the completed tank in zone 5 is one of the simplest procedures. Prefoamed panels of polyurethane foam insulation cast to the exact shape are hung on the tank and strapped down. Aluminum cladding is cut and fit on the line. Walkways are added and remote controls are connected. Decals and data plates are applied.

At this point, the tank container is complete, and it is moved to the storage yard for pick-up. The plant site has storage space for 160 tank containers.

Window to the Workshop

All offices are on the mezzanine level, above material storage. A long window that stretches almost the entire length of the plant looks out onto the shop floor. This window into the workshop is an important element in the layout of the plant, says Deakin. It gets every employee involved in the all-important production process.

The window overlooking the shop floor extends from the employee cafeteria, where team leaders can hold their team meetings in the quiet of the office but in full view of most of the container assembly stations. The window extends through the general office where engineers, bookkeepers, and personnel managers work and are never very far from a view of the people and processes they administer. The window extends into the private offices where the production engineer can see work in process and the personnel manager has a wide-angle view of the production floor.

Besides the certifications required by the many regulations covering the container industry and hazardous materials carriers, MTK Containers has applied for ISO 9001 and expects to receive certification in early 1999.

MTK Containers Limited is truly an international company supplying an international market. It is European invested, UK-based, operating under licenses from a German company, and receiving its certifications from a French agency. Its line of swap tanks is particularly popular in traffic between the UK and Europe, and its ISO tank containers will travel by ship, rail, and truck throughout the world.

MTK Containers Limited, Sunderland Enterprise Park (East), West Quay Road, Sunderland, Tyne & Wear, SR5 2TD, United Kingdom. o