HorizonPSI Addresses Process Issues in Systems
Part III Pneumatic Conveying Troubleshooting Series: HorizonPSI Addresses Process Issues in Systems
Have you ever thought about how one event in your life affected multiple situations in your day? Sometimes it’s the simplest of circumstances that cause the discomfort, but you’re battling so many responsibilities you don’t know where to start your diagnosis. Have you ever thought the same way about your process system? Often times a simple change within your system can cause problems. Human errors, change in humidity, a failed part or new ingredients could cause an issue with your system?
In Part III of our Pneumatic Conveying Troubleshooting Series, we will describe some common process issues and how to remedy these situations.
A process issue is a broad term used to describe a situation created by something acting outside of normal specifications causing poor results. Often, process issues are simple fails whose causes are easy to fix, but might go undetected for a variety of reasons. These things often happen when someone doesn’t realize how one change to a system can affect equipment up or downstream from the change. For instance, your facility is expected to increase output, so they increase the pounds per hour or increase the number of product changes per day. Therefore, employees are working quicker and not able to pay attention to simple issues and forget to change their system setup and then an issue surfaces.
It is not uncommon for operators or maintenance staff to be faced with one of the following process issues which can affect your system’s ability to convey.
Process Issues:
- Overfilling System Causes Line to Shut Down
- Ruptured Explosion Vent
- Moisture Inside Convey Lines
- System Settings Inadequate for Product Changes
- Convey Line Restrictions
Issue: Overfilling System Causes Line to Shut Down
A common issue that our Field Service Technicians experience is a reported pressure spike within a system causing a shut down and appearing as if there is a clog. After a brief inspection, the system would be restarted and perform just fine - until it happens again. As we all know, production interruptions are frustrating and cost money.
What our Field Service Technicians often find as the cause of the shutdown is the system being over filled, thus creating a high pressure signal. When a system is sized and controls are set to receive a particular amount of material or pressure, and that value is exceeded, it will build up pressure if it isn’t able to discharge that material before the sensor is triggered. When these convey systems are restarted, there is often a lag in the supply of new material, so it appears to be fixed, until it happens again. This situation often happens when production is increased, but other areas of the process line are not calibrated to handle the additional load.
Diagnosis:
When high pressure alarms sound, don’t always assume the convey line is clogged. Review the overall system set up to make sure all components and sensors are calibrated for the increase in production.
Issue: Ruptured Explosion Vent
Another issue our Field Service Technicians frequently run into is a ruptured explosion vent. The rupture can occur because of excessive/increased internal pressure or vacuum in the storage vessel or receiver. Similar to overfilling your system, increases in production can cause increases in pressure or vacuum that could rupture an explosion vent. These situations are often quickly diagnosed because of pressure/vacuum or explosion vent monitoring, but sometimes there could be other issues.
Diagnosis:
Have you changed any of your fans or pumps recently? A ruptured explosion vent can also occur if fans or pumps are being ran the wrong direction. Always check the wiring on a replacement fan or pump to make sure it runs the way your system is designed. Remember, the only way to fix a ruptured explosion vent is by purchasing a new one.
Issue: Moisture Inside Convey Lines
Moisture causes many dry ingredients to clump which affects how the materials convey often causing them to clog the line. Moisture can also cause stickiness inside the pipe lines from ingredient residue. So where is the moisture coming from? Finding the cause of the moisture within the system could focus on the product separator (cyclone), but where do you look when ingredients clump before they are processed?
Diagnosis:
Look for high moisture conditions in your ingredient receiving and storage. Proper ingredient storage or proper dehumidification of rooms or silos can reduce the risk of ingredient moisture and the resulting product clumping or change in consistency. Extreme differences in internal temperatures versus outside temperatures is hard on ingredient receiving and storage, so be aware of seasonal changes affecting your process. Also look for condensation in your intermediate storage, which might be more exposed to humidity if positioned away from dehumidified rooms. Should you experience line residue, consult our Field Service Team on our ReelKleen solution for cleaning convey lines.
Issue: System Settings Inadequate for Product Changes
Difficulties moving ingredients after product changes is an issue that you might encounter. In general, a range of blower settings can be used to convey multiple materials or products. Current settings could be in service for several years without a convey problem. So, what do you do when a slightly different formula is introduced and the product is similar, but you can’t make rate or the system doesn’t perform?
Diagnosis:
If your product changes, over time the performance of the ingredients could eventually be outside the current convey system settings causing performance issues with your system. Product consistency could be significantly different in one product change from what the system was originally designed for, or it could be an evolution of changes that cause the problem. Evaluating convey line sizes, blower speeds and airlock/feeder settings is a good start, if you have the expertise. If not, it may be a good idea to have your system resized by a HorizonPSI Field Service Technician and Engineering resource.
Issue: Convey Line Restrictions
You have material backing up in the convey line causing a high pressure spike and a shut down. You explore all the “normal” reasons for the blockage without finding the problem. At this point, you might be thinking, where else should I look?
Diagnosis:
An example of a convey line restriction is magnets. Magnets are used in many different processes to remove foreign metal objects from entering the product flow and contaminating the product. A magnet restricting an outlet is another place to look. One of our Field Service Technicians ran into a recent issue where a customer had a tray of magnetic bars across the outlet of their system and the magnet tray was a part of the system for a couple years. At installation, it appeared as if the magnetic bars were spaced far enough apart that they would not restrict the flow of product. However, they were not spaced far enough apart. The kibble started to orient in a way that would clog the outlet and cause a high pressure spike and sometimes a clog in the customer’s line. The solution was that the customer purchased a new tray of magnets that were spaced further apart. This is a great reminder that just about any restrictions put in the pipe line or on the inlets or outlets can cause any number of problems for a convey system.
At HorizonPSI, we understand your process must work for you to be successful. We are committed to safety and stand behind our service. Our Field Service Technicians are experienced and knowledgeable as well as OSHA trained. If you’d like to talk with a technician or schedule an on-site audit or evaluation, please contact Stephen Nelson, Director - Technical Services, at (785) 856-8110 or snelson@horizonpsi.com. After all, our business is your business.
