TECHNOLOGY

Watertight Seals

Tunnel construction involved in undersea tunnels or in city redevelopment tends to involve deep depths. A major technological theme in work at great depths is technology that is resistant to high water pressure. The precision components inside the shield machine must be protected from underground water pressure and earth pressure at great depths. We have developed and commercialized unique seals that can withstand high water pressure. These seals have been used in many construction projects under strict conditions, such as high water pressure, long-distance excavation, and high-speed rotation, so they are highly reliable.

• Cutter Drive Unit Main Seals

  Cutter Drive Unit Main Seals protect rotation bearing from external materials, such as sand, groundwater, and additives. Therefor the requirement for the main seal is to be able to sufficiently withstand cutter excavation earth pressure, ground water pressure, and additive injection pressure, and so on. Our seals produced by our company have been confirmed through testing to be able to withstand high water pressure up to 2.0 MPa.

  

• Articulation Seals

  Some shield machines are equipped with an articulation device as an auxiliary mechanism for small curve negotiation, and the machine consists of some bodies connected with a joint and can make an angle during construction in curve areas. Articulation seals are equipped in this joint part in order to prevent the intrusion of water. As with the cutter drive unit main seals, these seals have been confirmed through testing to be able to withstand high water pressure up to 2.0 MPa.

  

Tail Seals

Our company produces testing equipment with segment diameters of φ1 m, and conducts water pressure tests of high-water-pressure seals. The testing machines make it possible to perform excavation of the segment at the actual speed. Through these tests, we have confirmed that the tail seals of our company have a water pressure resistance of 2.0 MPa when combined with tail sealer.