In-Motion Weighing Systems

In-Motion Weighing Systems

In-Motion Weighing Systems

In-Motion Weighing Systems devices are designed to capture and record axle weights and gross vehicle weights as vehicles drive over a measurement site. Unlike static scales,in-motion weighing systems are capable of measuring vehicles traveling at a reduced or normal traffic speed and do not require the vehicle to come to a stop. This makes the weighing process more efficient, and, in the case of commercial vehicles, allows for trucks under the weight limit to bypass static scales or inspection.

Road applications

Especially for trucks gross vehicle and axle weight monitoring is useful in an array of applications including:

• Pavement design, monitoring, and research
• Bridge design, monitoring, and research
• Size and weight enforcement
• Legislation and regulation
• Administration and planning

In-motion weighing scales are often used for size and weight enforcement, such as the Federal Motor Carrier Safety Administration's Commercial Vehicle Information Systems and Networks program.In-motion weighing systems can be used as part of traditional roadside inspection stations, or as part of virtual inspection stations. Recent years have seen the rise of several specialty in-motion weighing systems. One popular example is the front fork garbage truck scale. In this application, a container is weighed—while it is full as the driver lifts, and again while it is empty as the container is returned to the ground. The difference between the full and empty weights is equal to the weight of the contents.

Rail applications

In-motion weighing system is also a common application in rail transport. Known applications are

• Infracharging
• Asset protection (imbalances, over loading)Asset management
• Maintenance planning
• Legislation and regulation
• Administration and planning

System's basics

There are two main parts to the measurement system: the track-side component, which contains hardware for communication, power, computation, and data acquisition, and the rail-mounted component, which consists of sensors and cabling. Known sensor principles include:

• strain gauges: measuring the strain usually in the hub of the rail
• fiber optical sensors: measuring a change of light intensity caused by the bending of the rail
• load cells: Measuring the strain change in the load cell rather than directly on the rail itself.
• laser based systems: measuring the displacement of the rail

Yards and main line

Trains are weighed, either on the main line or at yards. In-motion weighing systems installed on the main lines measure the complete weight of the trains as they pass by at the designated line speed. In-motion weighing on the mainline is therefore also referred to as coupled-in-motion weighing: all of the railcars are coupled. In-motion weighing at yards often measure individual wagons. It requires that the railcar are uncoupled on both ends in order to weigh.In-motion weighing at yards is therefore also referred to as uncoupled-in-motion weighing. Systems installed at yards usually works at lower speeds and are capable of higher accuracies.

Air applications

Some airports use airplane weighing, whereby the plane taxis across the scale bed, and its weight is measured. The weight may then be used to correlate with the pilot's log entry, to ensure there is just enough fuel, with a little margin for safety. This has been used for some time to conserve jet fuel. Also, the main difference in these platforms, which are basically a transmission of weight application, there are Check Weighers, also known as dynamic scales or in-motion scales.

Sources

Wikipedia In-Motion Weighing Systems