The 3 Most Overlooked Baghouse Preventative Maintenance Tasks
Baghouses can require much maintenance to keep in good working order. At times, maintenance planners and technicians might feel that some tasks are less important than others think and so they skip certain items. However, baghouse manufacturers that make those preventative maintenance schedules know that it’s actually many of the smaller, seemingly unimportant tasks that actually are the most crucial.
Let’s look at three specific tasks found on most dust collector PM schedules that are often overlooked and learn why they are absolutely essential to avoid more serious problems further down the line.
Regular Cleaning Differential Pressure Air Lines to Ensure Accurate DP Readings
We can say that differential pressure is the most important data metric to monitor on a baghouse. Carefully monitoring differential pressure gives vital insight into the current condition of the baghouse, including the filters, the airflow, collection efficiency, and more. Using this information, operators and technicians can make informed decisions about when to replace the filter bags, how to set the pulse jet cleaning system (frequency, on-time, off-time, pulse pressure, etc.) and have a reasonable guide to emissions levels from the unit among other things.
While so many operational decisions resting on this data metric, many facilities do not take steps to ensure these readings are accurate.
Eventually, dirt will make its way into the air lines running between the unit and the controller/gauge and cause problems. Starting with dust accumulating on the taps inside the unit, the air lines can then become clogged, bent or broken, or dirt can travel down the lines and foul the gauge or sensor.
A proper maintenance schedule will include the monthly or even weekly cleaning of these lines with compressed air. Technicians should disconnect the lines at the controller/gauge and blow back into the collector to remove any build up inside the lines.
Some may skip these tasks because they do not feel they are valuable, or out of ignorance. But when these lines become blocked and gauges and controllers provide false DP readings operators essentially must run blind. Many operational problems and poor maintenance planning decisions can often be traced back to false DP readings.
Read more info about this here: Baghouse Differential Pressure – How To Troubleshoot False Readings
Repairing and Maintaining Diaphragm Valves (Pulse Jet Baghouses)
Poorly maintained diaphragm pulse valves have a dramatic effect on the efficiency and effectiveness of a pulse jet baghouse. Leaking diaphragms waste huge amounts of (often very expensive) compressed air. More seriously, worn out diaphragms decrease the effectiveness of the cleaning pulses, which results in poor bag cleaning. Inadequately cleaned bags creates higher operating differential pressure increasing operating costs and lowers suction throughout the system (product dropout and damage to vented equipment).
Keeping the diaphragm valves in good working order is fairly simple and relatively inexpensive. Extra diaphragm repair kits should be kept on hand so malfunctioning valves can be repaired without delay.
Repairing and fine-tuning the pulse valves is often the cheapest way to save money on dust collector operation. By replacing worn diaphragms and setting the cleaning system properly frequently results in savings of 10% to 20% in operational costs and extends filter life significantly.
Repairing and fine-tuning the pulse valves is often the easiest way to save money on dust collector operation. By replacing worn diaphragms and setting the cleaning system properly frequently results in savings of 10% to 20% in operational costs and extends filter life significantly.
In addition to a visual inspection, it is often possible to tell which valves require maintenance simply by listening to them as they fire. Valves in good condition will have a quick, crisp sound when they fire, whereas valves needing repair will have a long, flat, sound. (Like a person holding their breath that gets punched in the stomach and gets the breath knocked out of them.)
Regular Leak Testing
Dye leak testing is the only sure way to diagnose problems in a baghouse with certainty. Regular leak testing helps operators to identify damaged bags before they start leaking excessively and causing emissions and performance issues. Maintenance technicians and planners can also use leak testing as part of a preventative maintenance process in order to diagnose problems elsewhere in the system that could be affecting the filters such as abrasion, chemical attack or temperature excursions.
On occasion, a defective filter will fail early and need to be replaced. In other instances there may be a temporary or unanticipated event that can cause of premature failure of filters. Once identified these should be investigated to ensure the incident does not occur again, and determine the extent of the damage done to the system. Examples may include: abrasion, thermal durability, and chemical attack.
For these reasons its often good to make sure your facility has enough leak testing powder on hand to perform at least one complete leak test on all of its systems.
While dye leak testing will always have its place, the use of triboelectric bag leak detection systems (also known as broken bag detectors) can speed up the process. Triboelectric detectors install after a baghouse and monitor PM emissions. They are sensitive enough to register PM levels far below the maximum emissions limit from EPA or other sources. This enables them to detect the slightest rise in emissions indicating a bag has begun to leak. Operators can even use the data to pinpoint the leak to the particular unit, compartment and even row within a pulse jet. This saves time and prevents a minor leak from escalating to exceeding a plant’s emissions limits and thus becoming a reportable event.
Do Not Skip The Little Tasks–They Are the Most Important!
When maintenance budgets get squeezed often decision makers think that cutting the “small” tasks and diverting attention to the “larger” tasks proves the best option. However, when it comes to baghouse maintenance often the little tasks are the most important and provide the most return on investment.