Topside Housekeeping
Take a walk around the outside of the truck scale. Examine the entire deck, scale pit, foundation and approaches for any major structural or surface problems.  Scale owners with scales that have any deterioration need to fix them right away.   Any deck and approach repair is not merely cosmetic; those damages will have a negative effect on the scale.  Flaking rust and crumbling concrete falling into the pit will add maintenance costs now, but in the future they will reduce the scales’ usefulness.

Check Deck Clearance
If you have a pit scale, while still outside the pit, use a crowbar to check the weighbridge for free movement both with and without a vehicle on the scale. If binding seems to be an issue, check the pit wall-to-deck clearance. If clearance looks good all around, with no debris between the walls and the deck, you’ve done all you can topside. The binding problem is coming from below. Get your boots, gloves, hornet spray and lights, and get ready to head into the pit to look things over (or better yet, call your scale guy instead).  Just remember to check the oxygen level in the pit before you go down in the pit.

Keep it Clean Under the Truck Scale
The most common cause of incorrect weighments is debris in the pit binding movement. Clean all dirt from each component. Remember, even though most scales these days are electronic, they still have moving parts underneath. Load cells still need to be able to deflect through their capacity range.  We recall the story we heard recently of a customer requesting a service call to figure out what was causing his scale to weigh incorrectly. It was a pretty urgent situation because the scale had been red tagged and his whole business was shut down while they tried to figure out the problem. Well, the service guy soon discovered the problem – a single piece of gravel wedged between the weighbridge and side of the foundation!

To cut down on future problems, the scale owner needs to invest in flexible T-Grip or T-Strip molding. These moldings, while being flexible enough to work with the movement of the scale, will keep debris from causing problems and eventual damage to the truck scale. Depending on the scale design, the molding might only be necessary to cover the end gaps where the trucks enter and exit the scale. Scales weighing open trucks or messy operations will also need side molding to protect against spillage falling into the pit.

Load Cell / Lever Hybrids
When you have a hybrid lever scale converted to digital readouts with an S-beam load cell, you need to check a few more items during the inspection.  Replace any damaged load cell cables rather than splicing them. Cable splices are prone to moisture entry, leading to a new host of problems. For further moisture safeguards, replace j-box desiccant, or fill the box with Waterguard Gel.

If rodent or radio frequency interference are problems, switch to a cable offering both rodent protection and EMI/RFI protection.  We recommend the EL147RP load cell cable. For protection against rodents only, run the cable through conduit or in the Rice Lake SURVIVOR® Cable Armor.  Finally, get a complete scale calibration with certified test weights with proven accuracy.  Actually, your best choice is to set up a quarterly service agreement with your local scale company.  They have the expertise and equipment to keep your truck scale running smooth year round.  In central North Carolina, the choice would be Central Carolina Scale out of Sanford, NC.

Unlike check rod binding, bumper bolt displacement is easy to spot.  Bumper bolts need to be tight so they don’t move on their own, yet maintain clearance when the scale is both empty and loaded.  Seasonal temperature and weather changes can cause concrete and steel to expand and bumper bolts can bind tight against the contact area.  If binding occurs, adjust bumper bolts to maintain proper amount of clearance for all conditions. Rice Lake SURVIVOR scales do not have bumper bolts.

The CLC rating is not a measure of weighbridge strength or rigidity, because weighbridge deflection is not measured in the NTEP test. It is irrelevant if the load weighbridge sags 1/10th of an inch, or 10 inches, as long as the scale weighs within the accepted tolerance. The scale’s CLC weight rating passes in either case. A high CLC rating could be given to an extremely flexible deck sitting on load cell mounts which are capable of accurately handling the side loading resulting from a severely sagging weighbridge.

The Rice Lake SURVIVOR® truck scale line boasts a 45 ton (90,000 pounds) CLC rating. With most legal highway weight limits being a fraction of Rice Lake’s rating, owners of a SURVIVOR scale can expect a long lifespan through the most rigorous weighing processes of two million weighments or more. NTEP provides a set of procedures for the uniform testing and evaluation of weighing equipment. For a truck scale to be NTEP-certified Legal-for-Trade, the entire truck is weighed, not just a single axle or group of axles. The SURVIVOR series is approved for up to 270,000 pound full scale capacity with a 90,000 pound CLC rating, earning NTEP certification up to 14 feet wide. NTEP has additional guidelines for truck scales, such as the required length of approach ramps. For clarification on your state’s requirements, contact a qualified dealer who can help you determine the best site for your scale to meet those guidelines. For North Carolina, contact Central Carolina Scale in Sanford NC.

Truck Scale Indicator

Cardinal’s 225 Navigator features transflective technology which allows the 225’s display to be viewed under any lighting conditions from direct sunlight to total darkness. One-inch-high (25 mm) weight characters make viewing easy. View up to 3 scales with total weight simultaneously with the optional dual scale input board; no special software is needed with Cardinal 225 Navigator digital weight indicator.

Entering, viewing, and storing truck names is easy with the 225 Navigator’s convenient Truck ID menu.  Complete alphanumeric descriptions for truck and material prompts make storing and recalling tare weight values quick and simple.

Concrete Deck
While a concrete deck needs approximately 21 to 28 days to cure, it offers greater resistance to rust and corrosion from road salt and generally requires less maintenance than steel decks, helping to extend the life of the scale. A concrete surface also yields better traction with rain and snow. Because of their design, concrete decks distribute the load over a wider area than steel decks.  Rice Lake SURVIVOR® Series concrete deck truck scales are poured at the job site and typically have cure strength of 4,000 PSI at 28 days. The concrete is reinforced with steel rods and a minimum of two wide-flange main beams and seven wide-flange beams below. The Rice Lake SURVIVOR® concrete deck design incorporates galvanized steel sheets working in conjunction with I-beams to ensure that concrete remains above the neutral axis of the weighbridge.

Many low cost models contain concrete below the neutral axis. Concrete below the neutral axis increases tension causing the deck to crack and eventual weighbridge failure.

Steel Deck
A steel deck typically involves less initial cost – there is no investment in concrete or the labor to pour it. A steel deck scale weighs less, which makes it easier to move or relocate if needed. It can be fully operational within a day, reducing production downtime.  Rice Lake SURVIVOR steel deck truck scale designs are consistent with the design standards used by the American Association of State Highway and Transportation Officials (AASHTO) and the federal Road and Bridge department. The diamond checkered steel tread plate is supported by wide flange structural I-beams positioned longitudinally with traffic flow.

Many other manufacturers use lighter beams, C-channels in the middle of the bridge or space beams further out from the center of the module to reduce the cost of the scale. Over time, this type of bridge can bow or dimple, causing inaccuracies in weighments, scale downtime and eventually complete failure.

One of the biggest reasons for choosing a pit type installation is space – or lack of it. A pit installation requires less space than a pitless installation due to the approaches, as sloped approaches to grade are generally required for pitless foundations. However, pit type scales require sump pumps and drains, and are more vulnerable to accelerated rust and corrosion due to the potential of standing water in the pit.