Container X-ray Inspection System
A container inspection center is usually close to a seaport container terminal. The center consists of two types of inspection facilities. The first of them is for checking the containers of cargo by utilizing big size equipment for X-ray during being loaded on the trailers. The second one is for single checking of all cargo in a container whenever the trailer inspection by X-ray shows a portion of cargo that is suspicious. Generally there are four different methods that are used for inspection.
In the first stage of inspection, a large-size X-ray DR (digital radiography) device, this device is used to inspect full containers sitting on their trailers. In case that inspection shows that the cargo is suspicious, the container and trailer are repositioned to a near position for inspection in order to get the inspector to open the container and check all cargo inside them one by one.
After the first shielding door opens, the trailer is pulled to the center of the inspection zone and halted. The trailer conveyor is then removed from under the trailer’s front wheels and returns to its original position in the entrance zone. At that point, the trailer conveyor takes over by once again raising the trailer’s two front wheels. After the shielding door is closed the entire container is exposed to X-rays emitted from two directions relative to the direction the container is heading, both horizontal and vertical. After the X-ray process ends, the No. 2 shielding door opens and the trailer is pulled into the exit zone. The waiting driver then boards the trailer and drives it from the inspection facility. After the X-rays pass through the container and are attenuated, a detector detects and measures them. If the X-rays are strong enough then the detector can easily convert them into electric analog signals and sends them to a computer for image-processing.
In case the result images identify objects that are suspicious and located in the container, extra processing increases the contrast sensitivity level which then magnifies the items inside for determining them accurately. The inspection images are transmitted to an electronic image data server, and the computer receiving the inspection data transmits the information to a data server. From there, the horizontal images, vertical images, and declared information are all transmitted to an inspector’s computer monitor. Containers are inspected at the rate of 20/h.
Conveying device the trailer conveyor is fixed to a trailer’s two front wheels and pulls the trailer forward. As the trailer is pulled forward at a set speed, the perpendicular X-ray beams from the vertical and horizontal X-ray sources pass through the container. The structure of the trailer conveyor is designed so as not to interfere with the X-ray inspections. A control for interlock prohibits the conveyor of the trailer from colliding with the shielding doors or together.
Safety equipment Safety equipment is installed to determine whether anyone is in the inspection zone, and an interlock prevents the X-ray equipment from operating when someone is detected. The following safety equipment is fitted to the facility: (1) Buzzer for confirming that the driver has alighted from the trailer (2) Safety confirmation device (device for confirming moving objects) (3) Surveillance camera (4) Emergency stop switch.