News
Tidal gates are built in coastal areas or near estuaries, which are used to block tide, store fresh water, discharge flood and drain waterlogging. When the tide rises, close the gate to prevent the tide from flowing back into the river, and retain the fresh water of inland rivers to meet the needs of water diversion and shipping. At low tide, when the tide level is lower than the river level, open the gate to discharge flood, drain waterlogging, scouring and silting. The tide gate has the characteristics of two-way water retaining and frequent operation. According to this working condition and operation requirements, the HED has been improved in structure, anti-corrosion and control.
Seawater anti-corrosion treatment technologies such as cold spraying or hot-dip galvanized aluminum alloy are mostly used on the surface of the gate body. It is required that all structural components should be welded or even not welded during on-site assembly to avoid damaging the coating. The HED is an optimized assembly structure, in which the main structure is divided into two parts: the gate body and the base, which are connected by pin shaft. The bottom shaft of the whole gate body is optimized as a full-length shaft structure to reduce gaps and greatly improve the water stop effect. The gate body adopts the process of integral welding and local cutting of the base hole to minimize deformation. The water stop at the end of the bottom shaft is made of flat cloth rubber material which is easy disassembled. As a vulnerable part, it greatly reduces the maintenance cost. The position for installing encoder is reserved at the bottom shaft to lay a solid foundation for product upgrading.
The load on both sides of the HED changes according to the change of water retaining height on both sides of the gate, that is, the load on both sides of the gate is a functional relationship with the change of water retaining height on both sides of the gate. The load on one side of the HED may change from tension to pressure or from pressure to tension, and the changed load is borne by the double acting hydraulic cylinder of the hydraulic system. The oil filling and oil return sequence of the rod cavity and rodless cavity of the double acting hydraulic cylinder changes the tension or pressure borne by the piston rod of the hydraulic cylinder. The control program of the HED sends different commands to the directional control valve in the hydraulic system according to the change of the load, so as to ensure the execution of the oil filling and oil return sequence of the rod cavity and rodless cavity of the hydraulic cylinder. Thus, it can ensure the implementation of two-way water retaining function of HED.
According to the specification requirements of JTS153-3-2007, DLT5358-2006 and the operating conditions of HED, the anti-corrosion technical requirements are applied by different areas. The anti-corrosion of atmospheric area shall be protected by coating or metal spraying layer. The anti-corrosion of splash area and water level change area should be protected by heavy anti-corrosion coating or metal thermal spraying layer plus closed coating, or resin mortar or coated organic composite layer with composite anti-corrosion metal layer. The anti-corrosion of underwater area can be protected by cathodic protection and coating or cathodic protection alone. When cathodic protection is used alone, anti-corrosion measures during construction shall be considered. Cathodic protection shall be adopted for the anti-corrosion of the submerged area. When the sacrificial anode is buried in the sea mud, appropriate anode materials shall be selected, and the reduction of driving voltage and current efficiency shall be considered.
As the driving device of HED, the service life of hydraulic cylinder directly affects the operation safety of the overall structure. Therefore, anti-corrosion technology and process requirements are put forward separately for hydraulic cylinder. The hydraulic cylinder barrel and other parts adopt the technical requirements for anti-corrosion in the water level change area. For the piston rod, the surface ceramic plating process is adopted. This process adopts wear-resistant ceramic coating, which has extremely high mechanical strength which can reach 130Mpa and stiffness which can effectively resist the impact force and shear stress of materials. The combination system has high strength due to the chemical combination formed by compound strengthening measures and special treatment. It also has excellent toughness and earthquake resistance, good integrity, good environmental compatibility and no environmental pollution.
In view of the adverse marine climate and the risk of overturning beyond the design standard during the operation of the two-way tide retaining gate, a special anti-overturning device is set at the upstream and downstream sides of the tide retaining gate. A fin type limit block is added at the riverside of the tide retaining gate, and a rubber limit belt (installation place of driving device) is added at the seaward survey.
