Ensuring Accuracy and Efficiency: A Comprehensive Guide to Conveyor Belt Scale Maintenance

Conveyor belt scales are critical components of various industries, from mining and agriculture to manufacturing and logistics. They play a vital role in accurately measuring and controlling the flow of materials, ensuring efficient operations, and optimizing resource utilization. To maintain the reliability and accuracy of conveyor belt scales, regular maintenance is essential. This article will delve into the intricacies of conveyor belt scale maintenance, covering the importance of maintenance, common maintenance tasks, and best practices to ensure seamless operations.

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The Importance of Conveyor Belt Scale Maintenance

Conveyor belt scales are used for a wide range of applications, including measuring bulk materials, monitoring production processes, and managing inventory. Their significance lies in their ability to provide real-time data that helps businesses make informed decisions, improve efficiency, and control costs. However, without proper maintenance, these scales can become inaccurate, leading to financial losses, production inefficiencies, and safety hazards. Here's why conveyor belt scale maintenance is crucial:

Accuracy and Consistency: Conveyor belt scales must provide precise and consistent measurements to support accurate record-keeping and process control. Regular maintenance ensures that the scale remains calibrated and reliable.

Compliance: Many industries, such as mining and agriculture, are subject to regulatory standards and trade certifications. Proper maintenance helps meet these requirements, avoiding potential fines or legal issues.

Cost Efficiency: Accurate measurements enable companies to optimize resource use, reduce waste, and minimize operational costs. Unreliable scales can lead to overuse or underuse of materials, resulting in financial losses.

Safety: Malfunctioning conveyor belt scales can create safety hazards. For instance, an inaccurate measurement may lead to overloading, potentially damaging equipment or causing accidents.

Common Conveyor Belt Scale Maintenance Tasks

Maintaining conveyor belt scales involves a series of tasks aimed at ensuring their proper operation. While the specific requirements may vary depending on the scale's type, here are some common maintenance tasks:

Regular Calibration: Calibration is the process of adjusting the scale to ensure it provides accurate measurements. Calibration should be performed at scheduled intervals or whenever there is a significant change in the operating conditions.

Cleaning and Inspection: Regularly inspect the scale for debris, material buildup, or damage. Clean the conveyor belt and scale components to prevent interference with the measurements.

Belt Alignment: Proper alignment of the conveyor belt is crucial for accurate measurements. Misalignment can result in uneven material distribution and measurement errors.

Sensor Check: Inspect sensors, load cells, and other electronic components for damage or wear. Ensure they are properly connected and functioning.

Belt Tension: Maintain the correct tension in the conveyor belt. Too much or too little tension can affect the scale's accuracy and lead to premature wear.

Roller and Idler Inspection: Check rollers and idlers for wear and damage. Replace any worn or damaged components to prevent belt misalignment.

Sealing: Ensure that the scale is adequately sealed to protect it from environmental factors such as moisture, dust, and temperature fluctuations.

Software Updates: If your conveyor belt scale relies on software for data processing, keep it up to date to benefit from improvements and bug fixes.

Best Practices for Conveyor Belt Scale Maintenance

To ensure the longevity and accuracy of conveyor belt scales, consider implementing these best practices:

Establish a Maintenance Schedule: Create a comprehensive maintenance schedule that includes regular inspections, calibrations, and cleaning. Stick to this schedule diligently.

Document Maintenance Activities: Keep detailed records of all maintenance activities, including calibration results, repairs, and replacements. This documentation can be valuable for compliance and troubleshooting.

Train Personnel: Train your staff on proper maintenance procedures and safety protocols. Ensure that they understand the importance of their role in scale maintenance.

Use Quality Components: When replacing parts, opt for high-quality, manufacturer-recommended components to maintain the scale's accuracy and reliability.

Monitor Performance: Implement a monitoring system that continuously tracks the scale's performance. This can help detect issues early and prevent costly downtime.

Emergency Plan: Have a contingency plan in place in case the scale experiences a critical failure. This plan should include procedures for shutting down operations and addressing safety concerns.

Conclusion

Conveyor belt scales are indispensable tools for industries that rely on material handling and production processes. Proper maintenance of these scales is essential to ensure their accuracy, efficiency, and safety. By adhering to a well-defined maintenance schedule, performing regular inspections, and following best practices, businesses can maximize the benefits of conveyor belt scales while minimizing the risk of inaccuracies, downtime, and costly repairs. In doing so, they can maintain a competitive edge in their respective industries and enhance their overall operational efficiency.

Conveyer Belt Scales. What Are They?

Conveyor belt scales, also known as belt scales or weigh belt scales, are an essential tool for a wide range of industries. These scales are used to measure the weight of materials as they are transported on a conveyor belt, providing an accurate and continuous weight measurement.

Belt scales are an important part of most bulk material handling facilities. A conveyor belt scale weighs items on a moving conveyor belt by weighing the belt load and measuring belt speed.

how does it work?

Conveyor belt scales consist of a weigh bridge, a load cell, and a belt speed sensor. The weigh bridge is mounted underneath the conveyor belt, and the load cell measures the weight of the material on the belt. The belt speed sensor is used to measure the speed of the belt, and the weight and speed measurements are combined to calculate the flow rate of the material.

Benefits

One of the key advantages of conveyor belt scales is their ability to provide a continuous weight measurement. Unlike static scales, which require the material to be weighed individually, conveyor belt scales can provide a constant weight measurement as the material moves along the conveyor belt. This makes them ideal for applications where a continuous flow of material is being transported, such as in mining, quarrying, and other bulk material handling operations.

Another advantage of conveyor belt scales is their accuracy. These scales are designed to provide highly accurate weight measurements, with a resolution of up to 1/10,000 of the load being measured. This level of precision is essential for ensuring the efficiency and safety of industrial operations.

Closing words

Overall, conveyor belt scales are an essential tool for a wide range of industries. They provide a continuous and accurate weight measurement, helping to ensure the efficiency and safety of material handling operations.

At American Scale we strive to bring you informed and useful content on all things scale systems related, including products from the top scale manufacturers. Be sure to check out our truck scale articles about truck scale foundation or how much do truck scales cost. We even have a guide to warranties. To learn more about bench scales, it would be good to check out our other articles such as “Bench Scale Basics'' and “How Much Does A Bench Scale Cost?”. These articles will help with the basics of bench scale ownership. Also, take a look at our “Common Problems With Bench Scales'', to help prolong the lifespan on your scale.

Belt Scales 101

Understanding Belt Scales

Belt scales are a unique method of retrieving accurate weight measurements in a more logistically challenging environment. They are not like a truck scale with a steel deck, nor is it like a bench scale with stainless steel components. Belt scales are scales on conveyor belts to ensure accurate and consistent material flow rates. Conveyor belts are supported by weigh frames that consist of load cells, rollers or idlers resting on the load cells, and speed sensors typically installed in tail pulleys on the conveyor belt. As material is carried on the conveyor, the load is measured by the load cells while speed and distance are collected by the speed sensors. This data is processed and displayed as pounds or kilograms per hour and total weight, on a weight indicator. Operators can control the flow of material to keep the supply to production lines consistent. Weigh frames are connected to weight integrators or process controllers that can communicate to peripheral equipment such as computers and printers.

CALIBRATING BELT SCALES

Calibrating your scale is essential to ensuring that you have an accurate measuring scale. Many scale manufacturers will have a Belt scale calibration that is a lot different from a conventional scale. A regular calibration schedule is good to keep your scale running optimally. If the material weighed on your belt scale is sold based on weight, you should contact a certified scale technician to perform regular inspections and calibrations as required by your local agency. A zero calibration should be performed daily; this is done by running the conveyor belt while it is empty to check the load cells and indicator register no weight on the scale. The load cells will be different from typical analog and electronic load cells.

MATERIAL COMPARISON CALIBRATION

To calibrate a Legal for Trade belt scale, you must perform a material comparison calibration. For this method, you need access to a certified scale such as a truck scale or a railroad scale. Material that passes over the belt scale must be weighed on the certified scale either before or after it’s weighed on the belt scale.

Use enough material for the belt scale to run for a minimum of 10 minutes or match the load obtained at maximum flow rate in one revolution of the belt to meet local agency requirements. After the material weight has been compared on both scales, a span adjustment can be performed on the belt scale to match the certified vehicle scale.

STATIC CALIBRATION

A static test weight calibration is most likely the simplest calibration method to perform. Belt scales require specialty calibration weights due to the unique design of a belt scale. Some systems allow weights to be semi-permanently attached to the weigh frame so the weight can be applied to the load cells as needed. For belt scale systems that don’t have this option, using a hanging weight set to check the load cells without the conveyor running is an alternative option.

A failed conveyor belt scale can bring the whole bulk handling operation grinding to a halt. So surely it is necessary to opt for reliability above all else.

The quarrying contract commits to removing a certain quantity of rock or gravel every single day. These numbers must be achieved – and have to be verifiable. If the company is engaged to load cargo for rail or sea transport, container after container has to be filled without the risk of overloading them. When working on a major demolition project specific targets for recycling building materials such as concrete and masonry must be met. In all these scenarios, uninterrupted operation is vital. When being forced to halt the conveyor belts unexpectedly because of a breakdown, valuable production time or the passage of goods will be lost.

Service levels will fall below what is expected. There could even be the risk of a hefty fine for breach of contract or for safety failings. A small but sophisticated piece of machinery, a belt scale is fitted to a conveyor belt to continuously measure the quantity of material being carried. The scale determines the amount of material by simultaneously weighing the belt load and measuring the belt speed. But if it develops a fault, this means that the conveyor belt comes to a standstill.

MAINTAINING YOUR BELT SCALE (WITH TIPS)

As mentioned before in the article, creating a regular service schedule for your scale will help keep your belt scale. To prevent common problems from shortening the lifespan of your scale, then setting up a maintenance schedule will help keep your scale running properly. The scale should be checked frequently to determine when calibration is required. It is recommended that zero calibration be checked every other day and that calibration be checked every week for several months after installation. Observe the results and lengthen the period between calibration checks, depending upon the accuracy desired.

Here are some tips to help keep your belt scale operating properly:

• Cleaning: Keep the scale area clean of rocks, dust and material build-up. Also clean surrounding scale accessories (scoreboard, remote display, junction box, scale indicators)

• Lubrication: The weigh idlers should be greased one to two times yearly. Overloading the weigh idlers with grease can change the tare weight and place the scale out of calibration. A zero calibration is necessary after greasing.

• Idler Alignment: The alignment of the scale service idlers to close tolerance is the single most important step in the installation of a belt weighing system. In order to minimize the dynamic effects of the moving belt and to provide a straight belt path through the scale, the weigh area idlers must be aligned to close tolerance.

• Belt Tension: It is important that the conveyor conditions remain constant at all times. Therefore, gravity-type take-ups are recommended on all conveyors where belt scales are installed. Conveyors which do not have a constant tension device will require calibration whenever the belt tension changes and the take-up is readjusted.

• Residue on Belt: Material can form a film on the belt which is carried continually around the belt and is never discharged. This condition is often true when handling wet, fine material. Belt scrapers may correct this condition. If the film can’t be removed, the zero will have to be adjusted. Any change in the build-up of the film adhering to the belt will require further adjustment.

CLOSING WORDS

Belt scales are a great way to keep production flow up and still get consistent accurate weight measurements. They are a good way to ensure that your operation does not have a slow down period as well as get heavy materials weighed and distributed. Be sure to visit our belt scale products page to see which scales are offered. At American Scale we are dedicated to providing unparalleled customer service and information. We have articles about truck scale installation, weighing applications, as well as truck scale foundations and warranties. Also be sure to check out our article about belt scale accuracy, to check out methods on ensuring scale accuracy as well as other articles like How much do truck scales cost.

Types Of Belt Scale Maintenance

Regular Belt Scale Maintenance

Regular belt scale maintenance is imperative to make sure your scale stays in proper working order and lasts for a long time. This maintenance should include clearing the scale area of debris, checking the condition of the idlers, check the scale frame and the conveyor belt, and zero testing the scale daily. Before maintenance can even begin make sure you install your belt scale in the correct location, checkout this blog post to learn more.

Clean Around The Belt Scale Frame

The most important part of belt scale maintenance is keeping the weigh frame clean. Debris in the scale area is generally caused by material falling off the conveyor belt and building up. This material can get wet and even freeze. Material buildup will cause issues like mechanical binding, inaccurate zero test results, and incorrect totalizing.

 If a belt scale weigh frame has just five pounds of buildup, the scale could register several extra tons every hour, causing a false totalization. In colder weather, we recommend running the conveyor belt for 10 to 15 minutes without a load to warm up the belt and make it more pliable.

Don’t Forget About The Belt Scale Speed Sensor

The speed sensor on the belt scale also needs periodic attention. The speed sensor (wheel sensor on return belt or a shaft-mounted encoder), it must be clear of debris use.

Keep Your Belt Scale In Top Shape

Performing a daily zero test on the belt scale is recommended and will help the user determine if and when the scale needs to be inspected. In good weather, the zero test should have normal results close that are showing good repeatability. If the zero test isn’t showing good repeatability, the belt scale should be checked for ice buildup.

 After clearing debris away from the belt scale frame, perform another zero test, and then run a span test (or static calibration test). If the span test results are not normal compared to periodic span tests, it is best to call a certified scale dealer to perform a thorough inspection and any calibrations necessary.

Belt Scale Calibration Program

Having a regularly scheduled calibration program with your scale company is always recommended to keep your belt scale weighing and performing at top shape. At the end of the day, performing a material calibration is the best method to use.

To learn more about the different belt scale manufactures, checkout this blog post.

Closing Words

At American Scale we strive to bring you informed and useful content on all things scale related. Be sure to check out our legal for trade truck scale system articles about truck scale foundation or how much do truck scales cost. We even have a guide to warranties. We also have articles on scale accessories, common problems to prolong your scales lifespan, weighing applications as well as what scale indicator works best with your junction box. To learn more about bench scales, it would be good to check out our other articles such as “Bench Scale Basics'' and “How Much Does A Bench Scale Cost?”. These articles will help with the basics of bench scale ownership.

I Need A Belt Scale – What Info Do I Need?

We get a lot of calls from customers that want a new belt scale and aren’t sure what information to provide us. This article will help explain some basic requirements that any scale dealer will need to start working on a belt scale project.

If you don’t know the answer to these questions – DO NOT worry! We can go through them together to figure out the best scale for your application. To learn more about the different companies that make belt scales checkout this blog post.

Info about the application / material being weighed:

Basic questions we will ask include:

1.       What type of application is this scale going to be used for?

a.       Inventory
b.       Load out
c.       Blending
d.       Batching control

2.       What accuracy are you trying to achieve?
3.       What is the maximum flow rate of the material (tons / hour)?
4.       What is the minimum flow rate of the material (tons / hour)?
5.       What does the material consist of?
6.       What is the size of the material?
7.       What is the density of the material (lb / cubic foot)?
8.       Is the material corrosive?

Info about the conveyor

Basic questions we will ask include:

1.       What is the conveyor type (stationary, stacker, portable, mobile crushing equipment)?
2.       What is the make of the conveyor?
3.       What is the model of the conveyor?
4.       What is the conveyor angle?
5.       What is the belt length (feet)?
6.       What is the belt width (inches)?
7.       What is the belt speed (feet / minute)?
8.       What is the idler spacing?
9.       What type of idlers do you have (standard trough, offset, channel inset, flat, catenary, etc)?
10.   What is the condition of the belt?
11.   Does the belt have splices? If so, what type?
12.   Is the area where the scale is going to be installed an explosive environment? 

Additional info that will help spec out your belt scale project

Basic questions we will ask include:

1.       What is the power source (110VAC, 240 VAC, 12-24VDC)?
2.       Where will the integrator (scale head) be installed?
3.       How far is the scale head from the scale frame?
4.       Do you want the scale to communicate with your control / automation system?

a.       What protocol are you looking for (Analog output, Ethernet IP, DeviceNet, Profibus, etc.)

5.       Do you want a remote display?
6.       Do you want to include a self storing test weight system (we recommend it!)?
7.       Do you want to control many belt scales from one integrator?
8.       Do you want to receive and/or monitor your data on your phone of the web?

 Last but not least, if you get us these dimensions, you are really ahead of the game!

To see what belt scales American Scale offers checkout our belt scales page.

Closing Words

At American Scale we strive to bring you informed and useful content on all things scale related. Be sure to check out our legal for trade truck scale system articles about truck scale foundation or how much do truck scales cost. We even have a guide to warranties. We also have articles on scale accessories, common problems to prolong your scales lifespan, weighing applications as well as what scale indicator works best with your junction box. To learn more about bench scales, it would be good to check out our other articles such as “Bench Scale Basics'' and “How Much Does A Bench Scale Cost?”. These articles will help with the basics of bench scale ownership.

Where To Install My Belt Scale?

Belt Scale Installation Considerations

So you are getting a belt scale…or you already bought one. Here are some things you need to consider when installing it.

Belt Scale Location:

First off, NEVER install a belt scale near the hopper dump or material load point. The belt in this area will be turbulent and this will affect accuracy and performance of the scale. If at all possible, you should place the belt scale in an area where the conveyor belt has completely settled. You generally want three to four idlers on each side of the scale to make it as smooth as possible.  Installing the belt scale near the head pulley or the tail pulley can cause similar accuracy and performance issues.

In addition, you should choose a location on the belt that has constant tension. Constant tension improves accuracy and overall performance. If possible, installing the scale near the tail section of the conveyor helps to eliminate tension variations. Many conveyors have tensioning devices to eliminate tension issues on the whole conveyor system.

Lastly, you should avoid installing the scale on steep areas and areas where the conveyor changes slope. Steep areas increase the chance of material rolling backwards which would impact the weighments. Curved locations may cause the belt to lift up when empty.

 Other considerations:

Inclement weather can cause major issues with belt scales. For one, freezing temperatures and moisture can cause ice and frost to build-up on the belt scale. Rain can mix with the material and add weight to the measurement. Wind can cause turbulence in the belt if the material is not very heavy. If possible, we recommend that you cover your belt scale with a conveyor cover if possible.

 Crusher, vibratory feeders, hammer/pug mills and other vibratory equipment should be avoided as well. If possible, the belt scale should be isolated from vibratory equipment and any / all electrical noise.

 Power – think about what type of power is going to power the scale integrator (aka indicator; aka scale head). The common types of power are 120VAC, 240VAC, 12-24DC. In addition to the power, running conduit is an important part of belt scale installation. Conduit is required for the power cables as well as the homerun cable that connects the scale to the integrator.

 These are just a few considerations you should think about before installing your belt scale.

Closing Words

At American Scale we strive to bring you informed and useful content on all things scale related. Be sure to check out our legal for trade truck scale system articles about truck scale foundation or how much do truck scales cost. We even have a guide to warranties. We also have articles on scale accessories, common problems to prolong your scales lifespan, weighing applications as well as what scale indicator works best with your junction box. To learn more about bench scales, it would be good to check out our other articles such as “Bench Scale Basics'' and “How Much Does A Bench Scale Cost?”. These articles will help with the basics of bench scale ownership.

Is My Belt Scale Accurate?

Is my belt scale weighing accurately?

We often have customers call regarding their belt scale, and they generally want to know how accurate the scale is. Usually, if they are calling, they don’t think the belt scale is right and they want to see what can be done to get more accurate weight data.

There are a few things to look at when assessing your belt scale.

 1. Environment & Scale Condition:

The first thing is the physical environment and the condition of the scale. There should be no build up of material around the belt scale. A lot of time, material will fall off the conveyor belt and get lodged in between the load cell assemblies and the conveyor frame. Also check the wires to make sure that none of them have been pinched, cut, or damaged. In general, the load cell wires terminate inside a junction box and that junction box goes to the scale head (or integrator). Check all the wiring including the wiring that goes from the speed sensor to the integrator. The two types of speed sensors you may have are generally one of the following:

• an arm with a wheel that tracks along the return side of the belt

• an encoder that is installed on the tail pulley with magnets

2. Scale Installation Location:

If all the wiring seems to be in good shape, you should look at where the scale was installed on the conveyor. You want to make sure and have three to four idlers of distance on either end of the scale. This is to make sure there is no “noise” in the system. Basically, you want the material to be traveling as smooth as possible while it is going across the scale. We’ve seen belt scales installed directly under a load out – that is not going to provide good data. You also want to check if the previously mentioned idlers (three to four before and after the scale) are on the same plane as the scale. You can do this by tying a string on the first idler and then pulling it out covering several in a row. The belt scale should be on the same plane as all the idlers before and after. If it is not, you can use shims to raise and lower idlers as necessary.

3. Belt Scale Parameters

Lastly, you want to check that the parameters were set up in the indicator correctly. A belt scale is a weigh in motion scale and certain variable data (belt length, belt speed, etc.) has to be set up correctly in the integrator in order for the  scale to weigh accurately. Belt scales are more complex than typical static scales (think static truck scale) and therefore not all scale technicians are familiar with them. There are several different belt scale manufacturers out there and each one has their own flavor of set up and software.

At the end of the day, the best place to start is to make sure the scale and surrounding area is clean and free of debris. Having a good preventative maintenance plan to prevent a lot of issues that you may encounter with your belt scale.

What Is A Belt Scale?

So what is a belt scale? A belt scale is a weigh in motion scale that is used to continuously measure material flow rates and totalize material amounts being transported on a conveyor belt.

Belt scales are an integral part of most bulk material handling facilities. Belt scale systems monitor raw material feed to crushers, mills, screens, boilers, preparation plants, and coal-fired power plants to ensure process material feed rates and maintain overall quality.

Belt scales are used in production and logistics, for measuring throughput and consumption in production plants, internal balancing of supply and discharge, load limit signaling, and batching at loading stations or metering hopper control. Belt scales provide vital information for the effective management and efficient operation of your business. The material weight is determined by weighing the belt load and incorporating other factors such as the belt speed and belt length.

Most belt scales on the market today are rugged and dependable. They often come as a single, dual, or four idler scale – in general the more idlers, the more accurate your scale is going to be. Many manufacturers offer self-storing calibration weights to make routine calibrations and checks quick, safe and simple.

Belt scales are common in the follow industries:

- aggregate & asphalt
- bioenergy
- cement
- chemicals
- energy & power
- food & beverage
- plastics
- pulp & paper