Pipes Jammed - Causes !!
Most of the project Engineers must have seen Pipes getting Jammed in Pneumatic conveying system. Be it Newly Purchased or newly commissioned. Ever wondered why??
Basic causes are listed below.
- Inadequate conveying blower.
- Smaller Pipe line size.
- Wrongly selected bends
- Smaller Bag Filters.
- Issues with timer
- Improper compressed air supply.
- Sticky and moist material being used.
Read further solutions for all above cases.
Inadequate Conveying Blower
An inadequate conveying blower cannot generate adequate force required to convey material to the desired distance. There are 2 parameters that are to be checked in a blower. First is the Flow rate and second is the pressure it can generate. Both the parameters should be adequately designed . Otherwise it will result failed system. Just by increasing the power of the blower or pressure will not solve your problem.
Smaller Pipe Line Size
Open the fridge and put him in. This logic wont work here. Pipe line sizes are properly designed to accommodate the flow of air and material. The size of pipes should be designed with a close watch on the material that is to be conveyed through the system and flow of air required for the material. Higher sized pipe will also result in jamming of pipes. and smaller pipes will also result in jamming of pipes. Velocity of air through the pipes is also an important parameter required to be considered while sizing of pipes. Cost cutting is a major factor in selection of smaller pipes.
Wrongly Selected Bends
This problem is generally not seen in systems designed by a professional. However, One should keep in mind that a Longer radius bend is always preferred in a Pneumatic Conveying System. Short bends tend to offer more resistance to flow of material and cause jamming of material in the pipes. Position of hte bends is also very important. In case the bends are not positioned properly then the it can compound the existing problems in the systems and result in jamming of pipes.
Smaller Bag Filter
This problem is quite frequent one. Most of the Peumatic conveying sytstems fails due to smaller bag filters. This probelm is almost subsequent to the previously stated issues like smaller pipes etc. The flow when designed is inadequate then the subsequent design of bag filter is also smaller. This results in jamming of pipes. When a designer designs a pneumatic conveying system with a lesser flow to reduce the cost of hte system. He also designs a bag filter that is suitable for a smaller flow. When designing a bag filter due consideration should be given to the actual air flow required and at least a 20% access area should be provided. Also the selection of bags should also be done properly. However, that topic is out of the scope of this topic. We will write a different blog on it.
Issues with Timer
Timer is one of the smallest part of the bag filter. But it is the most important part of the bag filter. If the timer fails bag filter will fail within few mins. A solid state sequential timer is suitable for this job. A proper on and off time for pulsing should be provided. In case the timer is not properly configured then it will lead to failure of bag filter, and subsequently the pipes will get jammed. We would recommend to have a spare timer with the stores always
You can see the complete programming and working of the timer in our videos in this link. https://youtu.be/osP9xD-Af5w
Improper compressed air supply
This reason is completedly in the hands of the user of this system. Sometimes a study flow of compressed air is not given to the system. In such cases, the bags don’t get cleaned properly and this leads to jamming of pipes. A study flow of 5-6 kg air should be given to the bag filter. In case there are cases of non-study flow of compressed air has been observed before it is recommended to have a separate compressor for this application.
Sticky and Moist Material being used.
Sticky and moist material should never be used in a pneumatic conveying system. This type of material leads to the choking of bags by making the bag wet. Subsequently, the bag doesn’t get cleaned and will eventually get jammed. Further, the pipes will also get jammed. Only Dry and free-flowing materials should be used.