Drainage pumps at pump stations are for preventing rivers from flooding. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) is drastically changing the way it orders the pumps. Previously, MLIT installed custom-made large pump units by small-quantity production. Now, public and private sectors will work together to develop compact, general-purpose, mass-produced-type pumps to lower costs.

Behind this shift was a succession of drainage pump breakdowns amid the frequent flood disasters in recent years. Repairing or exchanging parts of custom-made products require extra cost and time. This can be solved by using general-purpose, mass-produced compact units. Also, pumps would become affordable for municipalities with a weak financial basis.

By involving automakers with no prior experience in supplying drainage pumps, MLIT plans to make a compact-unit prototype within this fiscal year, and conduct verification tests from next fiscal year by installing the units in some pump stations.

Custom-Made: Engine 40 Million Yen, Reducer 23 Million Yen

In current practice, the Regional Development Bureau (local agency of MLIT) orders drainage pumps, and companies like Ebara and Kubota Kikou provide them. The inside of a drainage pump consists of three main parts: the engine, which is the power source, the reducer (transmission) that reduces the engine speed and converts to power (torque), and the pump that sucks up and discharges water.   

According to MLIT’s data, the engine part costs over 40 million yen by custom order, and large units can cost 75 million yen. A custom-made reducer costs about 23 million yen. The price of the pump part is not disclosed in MLIT’s data. As for maintenance, the item for custom-made product inspection shows 15 million yen as the annual cost. 

Pump Station Failure at Kuma River Flood Disaster

Because the drainage pumps are custom made, a breakdown leads to prolonged damage. The torrents of rain in Kumamoto Prefecture in July 2020 submerged the pumps at the pump station in the Kuma River system. The engines had to be replaced, but being custom made, it had to be made from scratch and took 10 months to complete.

In June 2019, at the Misato Pump Station (Misato-shi, Saitama Prefecture) along the Edo River, engine malfunction in one of the five pumps was found during a routine check. It took a week to repair, and until then, the pump station had to make it through by the processing capacity of remaining four units. In October that year, typhoon No. 19 hit the Kanto region, and the Misato Pump Station was put in operation as water levels rose rapidly in the Edo River. “We don’t know what would have happened if the pump was under repair,” a person involved looked back with a shudder. 

From One Custom-Made Large Unit to Multiple General-Purpose Compact Units

MLIT was acutely aware that the long-held practice of “custom-made, small-lot, large unit” orders was not only costly, but imposed significant consequences from breakdowns and malfunctions. So they revised the old mindset, and established the policy to: (1) develop a low-cost compact pump unit by combining general-purpose products, and (2) instead of installing one large pump, have multiple units of the newly developed compact pumps; thus maintaining the processing capacity. General-purpose products can be easily replaced when they break down.

To materialize this policy, they must first develop a compact pump. The MLIT expert committee held repeated discussions. Based on proposals like, “the same level of horsepower could be gained by general-purpose automobile engines instead of a custom-made one,” and “General-purpose reducers for cars or industrial use would be sufficient,” they decided the technical specifications. When MLIT disclosed the engine, reducer, and pump specifications, and asked private companies to provide products and technical cooperation, several companies applied.  

Toyota Industries Exhibits Its Prowess

The following companies took part in the development of the compact unit:

Engine: Toyota Industries Corporation, Mitsubishi Motors Corporation, Mitsubishi Fuso Truck and Bus Corporation

Reducer: Manufacturers of belts and other reducer parts

Pump: Ebara Corporation, DMW Corporation

Toyota Industries and Mitsubishi Motors will take part in the project by providing their existing products for the engines.

Although Toyota Industries had never supplied products for drainage pumps in the past, they will provide the 1GD-FTV type diesel engine for this project. This engine is used for Toyota Motor’s Land Cruiser Prado and HiAce, with accumulated production of 1.2 million units.

The diesel specification for the engine was MLIT’s request. Since pumps are intended for use at times of disaster, diesel oil would be the preferred fuel for its ease of handling, thus diesel engine was selected.

Attaching an existing automobile product to a drainage pump requires technical contrivance.

When a car goes uphill, the engine speed goes down, so you step on the accelerator to increase the speed. With cars, people can maintain a constant speed with the accelerator, but not with a drainage pump. If the water level changes and the load fluctuates, the engine speed must be kept constant. Cars have drivers who steps on and off the pedal, but drainage pumps do not have someone constantly controlling the accelerator. Toyota Industries will change the electronic control unit (ECU) specification to suit drainage pumps to enable automatic control of speed.

Mitsubishi Motors Also Provides Engine

Mitsubishi Motors offered their diesel engine for Delica D:5. They too have no experience providing products for drainage pumps. Since it is their first time, the company will connect the engine to the reducer and pump, make fine adjustments, and extract the issues.

Engine Price Drops from 40 Million to Below 2 Million Yen

So how much cost reduction can we expect from a compact pump combining general-purpose, mass-produced products? According to MLIT’s calculations, based on power output required for a compact pump, a custom-made engine costs over 40 million yen, but a general-purpose auto engine would be about 750 thousand to 2 million yen. As for the reducer, 23 million yen for a custom-made could be slashed to several hundred thousand to 5 million yen.

However, we must note that a custom-made large unit has a higher processing capacity per unit. Yet, considerable cost reduction can be expected by replacing a custom-made unit with several compact pumps. 

Also, compact units can reduce routine check costs significantly, which is about 15 million yen a year for a custom-made large unit. This is because inspection items for car engines can be applied to compact pump units.

New Unit’s Standards Become Future Requirement

MLIT and the participating companies are currently adjusting the fit of the parts (suriawase) to develop the compact unit, which will be installed and tested in a medium-scale pump station as early as January. When the function is confirmed, the standards will be fixed as tender requirements. The bidders such as pump providers are required to use engines and reducers that meet the standards. Therefore, the engines, reducers, and pumps of the companies participating in this project are likely to be adopted. 

If MLIT actively orders the compact units, price per unit will become cheaper with the economy of scale, making the price affordable for municipalities with financial limitations. More purchase from municipalities will create a favorable cycle of cheaper unit price.

Mitsubishi Motors and Toyota Industries Suffer Flood Damages

In the future, orders by the MLIT and municipalities for compact pumps will create a new demand of about 100 engine units a year for Toyota Industries and Mitsubishi Motors. However, for these companies that have produced over a million units, demand for 100 or so units contributes little to their bottom line. As for technical reviews, they only charge necessary expenses. So why are they taking part in the technical reviews for nothing, without returns?

Mitsubishi Motors and its business partners suffered damages in the 2008 Okazaki flooding and 2018 Okayama flooding at its Okazaki and Mizushima plants. Nishina Industrial, a Toyota Industries subsidiary, suffered damages in the 2019 Nagano Prefecture flooding. The companies say providing engines and technological cooperation is a social contribution to reduce the number of flood victims. The sales personnel at Toyota Industries explains their aim, saying, “If we develop affordable drainage pumps, even municipalities with weak financial base can buy them.” For the participating companies, the project is more like social contribution.

 (Fusako Taneichi, editorial staff)