Like any precision equipment, weighbridges require regular maintenance and calibration to ensure accurate results and long-term reliability.
In this article, we will explore the best practices for maintaining and calibrating your weighbridge to keep it functioning optimally and providing accurate readings.
1. Understanding Weighbridge Calibration
Calibration ensures that your weighbridge truck scale is reading weights accurately according to a known standard. The process involves adjusting the system so it can accurately measure the weight of objects placed on it, usually by comparing the readings to certified test weights or load cells.
Weighbridge calibration should be performed at regular intervals—typically annually—and whenever you suspect any issues with its accuracy, such as if the weighbridge has been moved, subjected to extreme weather, or after any repair work.
Signs Your Weighbridge Needs Calibration:
- Frequent discrepancies between expected and actual readings
- Displaying inconsistent weight readings
- Showing out-of-range values or error messages
- Difficulty zeroing out the weighbridge truck scale
- Structural changes to the weighbridge, such as settlement or misalignment
2. How to Calibrate Your Weighbridge?
Weighbridge calibration can be complex, and it’s often best left to certified technicians. However, it is important to know the basic steps involved. Calibration typically follows a process similar to this:
a. Initial Setup
Start by setting the weighbridge to “zero” to ensure that no weight is detected when no load is present. Make sure the platform is level, and the weighbridge is clean and clear of any obstructions.
b. Applying Test Weights
Once the weighbridge is prepared, you will apply known test weights. These should be certified reference weights, which are of known and verified accuracy. Apply a sequence of known weights in a prescribed pattern, starting from lower weights and progressing to higher ones.
c. Record the Weighing Results
After each test weight is placed on the platform, record the value displayed by the weighbridge. Compare these results to the actual weight of the load to identify any discrepancies.
d. Adjust Calibration Settings
If discrepancies are found, the calibration settings on the weighbridge’s indicator or software may need to be adjusted. This could involve modifying the calibration factor, scaling factor, or other settings that control the conversion of load cell signals to weight measurements.
e. Recheck and Verify
After adjusting the settings, repeat the test weights procedure to verify that the scale is reading correctly. The weighbridge truck scale should display results within a certain tolerance range—typically 0.1% of the applied load.
f. Document Calibration
After completing the calibration, record the process details, including the calibration date, test weights utilized, and any adjustments performed. Regular documentation helps track the history of your weighbridge and is useful for audits or compliance.
3. Weighbridge Routine Maintenance Checklist
Regular maintenance is key to ensuring the longevity and accuracy of your weighbridge. A well-maintained weighbridge will function more efficiently, reduce downtime, and save costs over time.
a. Visual Inspections
Perform regular visual inspections to check for obvious damage or wear, such as:
- Cracks or deformities in the platform or frame
- Loose bolts or components
- Signs of rust or corrosion
- Broken or frayed cables and wires
- Accumulation of debris, dirt, or foreign objects on the scale
b. Cleaning the Weighbridge
A clean weighbridge ensures that contaminants do not affect its performance, and it makes the inspection process easier. Regularly clean the platform, ramps, load cells, and any exposed areas. Use mild cleaning agents and avoid harsh chemicals that could damage components. Clean any debris that could obstruct the vehicle’s sensors or load cells.
c. Lubrication and Moving Parts
Lubricate all moving parts, such as the ramp hinges, to prevent rusting and reduce friction. Regular lubrication also helps prolong the life of the weighbridge’s mechanical components and keeps the scale moving smoothly.
d. Inspecting Load Cells
Load cells are integral to the weighbridge’s functioning as they measure the weight being applied to the platform. Inspect them for:
- Physical damage or corrosion
- Loose connections
- Signs of wear or dirt accumulation
- Proper mounting
e. Checking the Indicator and Display Unit
Ensure that the indicator and display unit is functioning properly. Check for any error codes, display issues, or faulty readings. Regularly test the system by weighing a known quantity and comparing it to the expected weight.
f. Testing the Weighing Accuracy
Regularly test the accuracy of the weighbridge by weighing a test load or known weight. You can finish the accurancy test in the form of test weights or calibrated reference materials. Record the results and check if the readings fall within the allowable tolerance level.
4. Weighbridge Components to Monitor for Maintenance
A weighbridge consists of several components that require attention to ensure optimal performance. These include:
- Deck Surface: The surface of the weighbridge must be free from debris, cracks, and wear that could impact the accuracy of measurements.
- Load Cells: These are the sensors that measure the weight of the vehicle. Load cells should be checked regularly for damage or misalignment.
- Indicator and Display: The weighbridge’s digital display and indicator should be inspected for proper functionality. Ensure that the display is clear and readable.
- Hydraulic System (for pit-mounted weighbridges): If your weighbridge uses a hydraulic system, the pressure and fluid levels need to be monitored.
- Cables and Wiring: Inspect the wiring for wear or corrosion. Faulty wiring can lead to inaccurate readings or complete system failure.
- Weighbridge Pits: If applicable, the pit should be checked for debris, water accumulation, or any structural issues that could affect the weighbridge’s performance.
- Supporting Structure: Check for any rust, cracks, or instability in the supporting framework of the weighbridge.
5. Additional Tips for Maintaining Weighbridge Accuracy
- Avoid Overloading: Never overload the weighbridge beyond its rated capacity. Excessive weight can damage load cells and other components.
- Use of Protection: Install protective covers to shield load cells and cables from weather conditions and physical damage.
- Monitor Environmental Factors: Be mindful of temperature fluctuations, moisture levels, and ground conditions as they can influence the accuracy of your weighbridge. Regular checks will ensure your weighbridge is calibrated to take these factors into account.
- Professional Servicing: While routine checks can be done in-house, it’s recommended to have the weighbridge professionally serviced every 1-2 years. A professional technician can perform in-depth diagnostics and repairs that may not be visible during regular inspections.