Section 3 Mechanical Equipment for Civil Works

Article 74. (Article 74) General requirement

1.Maintenance works

The purpose of the maintenance work at the hydromechanical equipment is to keep the equipment safe and certain conditions for the long time.

The checks of the equipment must be implemented periodically as a general rule, but additional checks are conducted as needed for example before/after natural disaster.

At the maintenance work and/or check, it is necessary to get rid of trashes in order to operate the gates certainly as well as to replace disposables.

Periodical checks by actual operation are desirable to keep the equipment in good condition.

Article 75. (Article 75) Conditions of gates

1.1Rust and wear

Corrosion at the bottom of the gate may develop rapidly, and corrosion caused by galvanic corrosion may become seriously at the limited part of a gate. Attention must be paid sufficiently to these phenomena at the maintenance.

Deterioration of the coating causes corrosion of the base metal. Therefore, condition of the coating must be checked carefully. Also the coating must be checked frequently as much as possible by means of observation, measuring thickness and so on.

The typical point at the visual check for coating is whether the following phenomena occurred or not;

-Blistering

-Cracking

-Peeling

-Chalking

2.Movement of gate

At a gate operation, the movement of gate leaf must be stable and an abnormal vibration and an abnormal sound must not occur. In addition, a gate must not be hooked unevenly. If a gate is hooked unevenly, there may be problems in water tightness and resting condition.

3.Positioning of gate

In many cases, a gate must be operated for detailed control of the reservoir water level and discharge volume. Therefore, position of the gate must be recognized correctly.

4.Water leakage from gate

Seal part of a gate may lose the function because it must endure under friction, pressure, deterioration, deformation and damage caused by intervened trashes. Attention must be paid to the above matter, and a seal rubber must be replaced if it is damaged.

5.Operating condition

When a gate is kept at minute opening (crack opening) for a long time, Vibration may occur and seal rubber may be damaged. Attention must be paid to the gate position.

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