WB-X800P I-Beam Steel Pit Type Truck Scale

What does a pit installation give the site?

The ramps at either end of a surface-mounted scale demand a considerable length on top of the platform itself. WB-X800P has no ramps: the platform sits in the pit and its top surface finishes level with the surrounding paving. The scale becomes a section of the internal road. A lorry drives straight on, is weighed, and leaves on the same plane to continue on its way.

This arrangement is decisive in particular situations. If the distance between the factory gate and the office or production hall is short, a ramped scale will not fit in that space. If vehicles must turn as soon as they leave the scale, a trailer coming down a ramp finds no room to turn. If the lane holding the scale is shared with forklifts, loaders or pedestrians, a raised platform becomes an obstacle. A pit installation solves all three at once.

Having the platform at road level also makes a difference to driving. With no ramp to climb, there is no throttle or braking load on the scale; horizontal forces fall, weighings settle sooner and the platform’s structure is strained less.

Structure of the I-beam steel platform

The platform’s backbone is built from rolled IPE I-sections. The I section gives high resistance to bending and takes heavy wheel loads down to the cells without inflating the platform’s own weight. The beams are covered with a top plate at least 10 mm thick; this lower limit is set so that the concentrated load from the wheel of a loaded mining truck or a full concrete mixer is spread without the surface sinking.

For a steel platform working in a pit, surface protection and ventilation matter as well. The underside never sees daylight and stays damp, so the corrosion protection of the paint system, the welds and the beam seats over each cell should be discussed before installation. On sites crossed by vehicles carrying fertiliser, salt or chemicals, this is settled at the quotation stage.

The compression load cells under the platform have a nominal capacity of 30 t, stainless steel bodies and IP68 protection; their accuracy class is OIML R60 C4. Standard mounting kits limit the side force a braking or angled vehicle applies to the platform and keep the measurement from drifting.

Planning platform size and capacity

WB-X800P is built 3 m wide in nine lengths between 6 and 22 m. Capacity is kept low on short platforms and high on long ones, because platform length also limits the total weight of a vehicle that can stand on it:

• Short vehicles: a 6 m platform on four cells at 40 t only; an 8 m platform, also on four cells, at 40–60 t
• Rigid trucks: 10 or 12 m on six cells, rated 40–60 t
• Heavy trucks: 14 m on six cells, rated either 60 or 80 t
• Articulated lorries: 16 or 18 m on eight cells, rated anywhere from 60 up to 100 t
• Drawbar and long combinations: 20 or 22 m on ten cells, rated anywhere from 60 up to 100 t

With a pit-type scale, the length decision is even more permanent than with surface models; extending the platform means rebuilding the pit. So, besides today’s fleet, the longest combination that may reach the site in the coming years should be taken into account. For capacity, a reasonable margin is left above the heaviest loaded vehicle. For example, if trucks leaving a quarry approach 70 t when loaded, choosing 100 t rather than 80 t leaves a safe band for overloaded trips.

Divisions run from 20 to 50 kg and work together with the indicator’s dual-range weighing. Tare weighings of empty vehicles are read in the lower range with a fine step, loaded vehicles in the upper range with a step that suits the capacity.

Use by sector

Mining and quarries. Trucks carrying ore and aggregate are heavy and have short wheelbases, so they put their load on a small area of the platform. The I-beam structure and thick deck plate are chosen for that concentrated load. Having the scale at road level at the quarry exit also removes the problem of climbing a ramp on muddy tyres.

Construction and ready-mix concrete. Mixers, tippers and plant pass through the same entrance all day. A pit-type scale works within that traffic without cutting across the site or plant road.

Steel industry. In scrap buying and in billet and coil dispatch, both incoming and outgoing tonnage carry commercial consequences. For heavy, concentrated loads, a premium load-bearing structure helps measurement stay consistent over the long term.

Agriculture and livestock. At businesses that weigh vehicles carrying feed, silage, grain or livestock at the gate, a scale offering a level crossing to everything from a tractor with trailer to an articulated lorry makes daily work easier.

Weighing indicator and software

On the electronic side of the measuring chain sits an indicator whose analogue-to-digital stage is a 24-bit sigma-delta design. A 1/30000 conversion resolution and vibration-filtering software give a stable value despite the shaking of a heavy vehicle with its engine running. The indicator’s dual-range function allows a finer interval in the lower range for legal-for-trade weighing, and its 26 mm backlit LCD digits suit an operator reading from a distance. The weighbridge software archives weighings and turns them into reports in five file types (spreadsheet, XML, PDF, HTML and TXT), and an optional web database provides remote access. Once traffic lights and plate recognition are added, the queue at the factory entrance runs in a more orderly way.