The particularity of the operation of Marine elevator
Because the Marine elevator still needs to meet the normal use requirements in the course of ship navigation, the swing heave in the operation of the ship will have a great impact on the mechanical strength, safety and reliability of the elevator, and can not be ignored in the structural design. There are six forms of ship’s swaying in wind and waves: roll, pitch, yaw, heave (also known as heave), roll and heave, of which roll, pitch and heave have relatively great influence on the normal operation of ship equipment. In the Marine elevator standard, it is stipulated that the ship roll within ±10°, the swing period is 10S, the pitch is within ±5°, the swing period is 7S, and the heave is less than 3.8m, and the elevator can operate normally. The elevator should not be damaged if the maximum roll Angle of the ship is within ±30°, the swing period is 10S, the maximum pitch Angle is within ±10°, and the swing period is below 7S.
In view of such conditions, the horizontal force on the guide rail and car of the Marine elevator is greatly enhanced when the ship is rocking, and the mechanical strength of the structural components in this direction should be improved accordingly to avoid the accident of stopping the elevator caused by structural deformation or even damage.
The measures taken in the design include reducing the distance between the guide rails and increasing the section size of the guide rails. The elevator door should be equipped with a device to prevent natural opening and sudden closing when the hull shakes, so as to avoid the wrong action of the door system or cause safety accidents. The drive engine adopts seismic design to prevent the accident of capsizing and displacement when the hull shakes greatly. The rocking vibration of the ship during operation will also have a greater impact on the suspension parts of the elevator, such as the accompanying cable transmitting signals between the car and the control cabinet, measures should be taken to add protection to prevent danger, so as not to cause mutual entanglement with the elevator parts in the shaft due to the swaying of the accompanying cable, damaging the equipment. The wire rope should also be equipped with anti-falling devices and so on. The vibration frequency generated by the ship during normal navigation is 0 ~ 25HZ with a full amplitude of 2mm, while the upper limit of vertical vibration frequency of the elevator car is generally below 30HZ, indicating the possibility of resonance. Therefore, appropriate preventive measures should be taken to avoid resonance. The connectors in the control system should take anti-loosening measures to avoid system failure caused by vibration. The elevator control cabinet should carry out impact and vibration test.
In addition, in order to ensure the safety of equipment and improve the automation level of the system, it can be considered to set up a ship’s oscillation detection device, which will send an alarm signal when the sea state indicator exceeds the normal working range acceptable to the Marine elevator, stop the operation of the elevator, and stabilize the car and counterweight respectively in a certain position of the elevator shaft through the navigation fixed device, so as to avoid the inertia oscillation of the car and counterweight with the hull. Thus causing damage to elevator parts.