When purchasing a new scale make it a point to understand how the weighbridge is designed. The quantity, type, size, and spacing of the I-beams are a good indication of a scale’s ability to handle demanding truck traffic.

Preventive maintenance priorities

Common sense maintenance initiatives for the following truck scale components can help avoid unexpected breakdowns and prolong equipment life.

1. Calibration. Every truck scale should be calibrated and tested by a state licensed servicing agency using no less than 25,000 pounds of certified test weight. The scale’s calibration interval is determined by its frequency of use. At a minimum, calibration should be conducted once every six months. For more heavily used scales, monthly or quarterly checks may be necessary. These calibrations will improve accuracy and expose potential problems before they become serious.

2. Weighbridge. Weighbridge maintenance is essential to prolonging the life of your equipment and keeping it in top operating condition. Removing the scale from the foundation, sandblasting all of its steel surfaces, and repainting it with a high solids urethane primer and top coat is something that should be done every eight to 10 years depending on environmental factors. Coating the underside of the weighbridge with an asphalt emulsion coating will also substantially reduce rust and corrosion of the weighbridge on non-visible surfaces.

3. Foundation. A scale’s performance is only as good as the integrity of its foundation. Keeping this foundation clean and free of mud, water, and debris will improve the performance of your scale. Material buildup around load cell stands, exposed cables, and wet junction boxes should be avoided. A quick visual check of sump pumps and drains should be done on a monthly basis. The concrete’s condition and the approach or pit coping should also be inspected regularly. Any cracks in the concrete or heaving due to frost can have an adverse effect on scale performance. Head walls and pit walls should be checked for alignment and structural defects. Approaches to and away from the scale should be level and ensure a smooth transition of truck traffic on and off the scale platform.

4. Load cells. Load cells are the heart of every electronic scale. They should be inspected for frayed cables, cracked or loose connectors, loose bolts, improper alignment, and potential buildup of mud and debris around the load cell. Canister type load cells should also be checked for rust or holes. Even stainless-steel load cells can rust. To reduce damage from lightning or surge voltage, a transient bypass cable should be installed at the load cell. This can dramatically reduce the effects of ground surges.

5. Junction box. Internal condensation is one of the most common problems associated with junction boxes. Moisture can occur not only from heavy rain and snow, but also from changes in barometric pressure and temperature. A stainless-steel junction box promotes internal condensation and is often more vulnerable to this type of problem. Newly developed junction boxes are made from fiberglass reinforced polyester and can reduce or eliminate the effects of internal condensation. These boxes also contain superior gasket design to help equalize pressure within the box.

6. Bumper bolts. Although there are truck scale designs that eliminate the need for bumper bolts, many older designs still require them. Frequent inspection is required on these models.