By Suzi Fraser Dominy
The new mill project was started in 1997 and scheduled for completion in 2000, as part of Nisshin’s centenary celebrations. A struggling Japanese economy set back construction, but October 2002 saw the 500 tonne wheat (360 tonnes flour) per day G-Mill finally come on stream, bringing the capacity of the Tsurumi plant to 2,150 tonnes per day.
The original 100-year-old Tatebayashi Mill could now be retired. With the loss of its 230 tonnes, Nisshin Flour Milling’s net capacity has thereby increased from 8,080 to 8,350 tonnes per day.
Built at a cost of Y9 billion (approximately U.S.$75 million), the G-Mill occupies a 1,200 square meter dedicated building alongside the A, B, C, D, E and F Mills in the 26 acre Tsurumi mill complex in the Keihin industrial area of Tokyo Bay.
Earthquakes are an ever-present threat in Japan. Nisshin has spared no expense in ensuring that the new mill is as well protected as possible.
Even from the outside, the G-Mill looks different from most, with clean lines and large windows on all eight floors. Step inside and the impression is confirmed. The mill, supplied mainly by Buhler AG of Switzerland, is a showcase in every respect and visits from customers and the public are both encouraged and accommodated in the design.
In the ground floor reception area, visitors as well as mill operators, must don not only the hats and white coats customary for any mill tour, but also paper over-shoes, as part of the strict hygiene standards. From here, a spacious elevator is taken, which opens onto an observation deck on each of the seven milling floors, where the milling processes can be viewed through large picture windows.
Clean and green
Inside the air-tight production rooms, filtered air is pumped through to each floor at a rate of 3,300 cubic meters per minute, keeping the pressure slightly positive and providing an effective hygiene measure. During Tokyo’s hot and humid summer months, the air is cooled to lower the ambient temperature. This close attention to hygiene is evident throughout the plant, from the use of sealed coating to the flooring to the reduction of dead spaces that might harbor insects and the use of easy-to-clean rollermills.
Nisshin has ensured that the G-Mill is not only clean but green as well, earning it ISO-14001 environmental management certification to add to its ISO 9000 series quality qualification. Oil-free compressors, high efficiency transformers and motors, energy efficient, capacity-controlled fans and blowers and a centralized control system for the lighting are among measures incorporatedinto the mill design.
Automated for efficiency and quality
It was Nisshin’s objective to build a technologically advanced flour mill: "the mill of the 21st century," with a high level of automation and built-in tracking systems from grain intake to finished product, to reduce labor costs and ensure complete control of production and product quality. The result is a fully automated mill, from wheat intake silos, through blending, tempering, finished flour selection from each sifter, to flour silo selection and inventory management. It is designed to be manned by a single operator, although in these early days it is temporarily staffed by two operators, working 3 shifts per 24 hours, five days a week. Downtime will be reduced as fine-tuning is completed and optimal running parameters established.
The efficiency of the G-Mill raises the Tsurumi plant production performance to 4,150 tonnes per worker per year as compared with the company’s average of 3,700 tonnes/worker per year, itself well above Japan’s national average of 1,590 tonnes/worker per year.
Consistent flour quality is one of the most important benefits that automation has brought to the plant. Automated features installed for this purpose include: vibro-dischargers for the wheat tempering silos to prevent plugging at the bottom of the bin and ensure stable discharge; controlled flow rate to the 1st break rolls and frequency controllers for every detacher in the mill to allow operators to adjust the grind. On-line NIR monitors check finished product quality around the clock.
The G-Mill is a dedicated bread flour plant, supplying bakeries in the Tokyo district. Japanese consumers are known for their discernment and gauging bread quality is no exception. In addition to the 12 sifters and 13 purifiers, 35 rollstands make up the tally of key equipment — a little higher than the number one would typically see in a western mill of comparable capacity. Nisshin’s management explained that since cooked rice is white, Japanese consumers have come to equate whiteness with quality; to get the high extraction rates and low ash demanded by their customers, a long, gentle process is necessary.
The plant uses no chemicals, either as flour improvers or for sanitation purposes, relying instead on its stringent quality control and hygiene standards. For pest control, a double-impact infestation control system is applied after grinding and handling, ahead of packaging and bulk loadout. The G-Mill has its own quality control center on the first floor, which is divided into two sections. In the first, routine analyses, such as ash, moisture and protein, particle size determination by micro-track, bacteria counts and HPLC (High Pressure Liquid Chromatography) are carried out. The second is a test bakery and noodle testing room, which is also used for product development to meet the requirement for the wide range of noodle products demanded by the Japanese consumer. In common with the rest of the mill, both are on full view to visitors through large windows from an observation area.
Bulk and unit storage capacity has had to be expanded in the Tsurumi complex to accommodate the additional requirements of the G-Mill. 2,800 tonnes of bulk flour storage capacity has been added to the existing 9,500 tonnes.
Tsurumi sources U.S., Canadian and Australian wheats and uses both wheat and flour blending methods to produce 250 different flour products. Mills A-F produce cake flour, bread flour, durum, Chinese and Japanese noodle flour, while the G-Mill is a dedicated bread flour mill.
Tsurumi ships 45% of its output in bulk. The mill has nine bulk loadout stations, each with their own rebolting sifter system.
Packaging for the whole Tsurumi plant is centralized. Five lines handle 25kg flour packaging, with further lines dedicated to 1kg and 500g household flour, durum, shorts and feed.
Capacity of the automatic rack warehouse has been increased by 176,000 bags, bringing it to a total capacity of 504,400 bags. An additional 398,000 bags can be stored in a flat warehouse.