The following diatribe or rant is a dramatization, the names have been changed to protect the innocent...
Friday started off as any other day, only a bit better than most days because it was a Friday! Things at the plant had been running smooth, business seemed to be improving and we all hoped "free parking" in the company lot would soon be reinstated. Three dollars a day to park in the company lot seemed fair at first but after a while it all adds up!
All systems were purring along, in fact things were going well, perhaps too well. Many routine maintenance "tasks" had been put on the back burner due to some staff reductions. Sadly one of the easiest PM chores to ignore had to do with checking the filters in our baghouse. No one ever really wants to climb up on the roof unless of course it is July 4th!
Little did we know that a small tear had began in one of the bag filters. Steadily the bag filter leak grew larger and larger allowing more dust to escape from the broken bag. The weakened bag filter continued to fail, more dust was escaping. It was almost as if the dust wanted to run away from the bag house that had held it captive.
Suddenly a failure of catastrophic proportion occurred, a domino effect caused by air flow, dust, and failing bags, raged through the baghouse. Only one small bag remained intact to prevent all of the dust from exploding into the atmosphere. Quickly, under the extraordinary amount of pressure and debris, the last bag filter gave way. A cloud of dust roared from the bag house in a menacing swirl of darkness, temporarily darkening the sky over the "pay to park" company lot.
Alright, I am no Stephen King...but a situation like this could occur if you have a filter failure in a baghouse. One of the best ways to monitor particulate emissions is to install a simple device designed to detect broken bags in a dust collector before a catastrophic failure occurs.
Monitor offers a product we call the DustAlarm. The DustAlarm is a broken bag detector, or a triboelectric particle emission monitor, the DustAlarm is designed to notify you when the amount of dust in the air flow begins to increase due to a pending filter failure.
The DustAlarm broken bag detector provides reliable and economical detection of leaks and filter failures in many powder and bulk solid industries. As mentioned, the DustAlarm is a triboelectric particle emission monitor. Triboelectric measurement has been used for years for broken bag detection, the phenomenon, also called "particle impingement" or "frictional electrification" pertains to the resulting charge transfer when one material rubs or impacts another. The result of a dust particle collision with a stainless steel probe is the generation of electrical signals which are continuously monitored and analyzed by the electronics. When the signal exceeds a preset level (such as what occurs when a bag begins to fail), a time delay is initialized. If the signal remains above the preset level for the duration of the delay, alarm relay outputs are "energized". These relays can be used to go to an alarm or to shut down your system to allow you to inspect your bag filters and determine which filter is beginning to fail.
For more information on the DustAlarm please refer to sales bulletin # 723. If you have any questions concerning your application please give us a call. One of our application engineers can work with you to make sure that the DustAlarm will help prevent the sky's above you from growing dark!
Director of Sales