Roots Blower Help Line: Blower Ingesting Product

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Blowers are only designed to move air (gas), not solids. Overtime ingesting product can cause major damage to the blower.

This unit has ingested product for quite some time. Most likely failure to filter the inlet air caused contamination.

The product is now lodged inside of the impeller lobes and has abraded the tips and ends of both impellers. The wear of the impeller tips will reduce the efficiency of the blower. Where is the product going once it passes through the blower? Is the silencer starting to clog?

Ingesting-Product-2Impellers are worn from exposure to product (fly ash) in process. Caught early, most impellers are repairable by welding and machining. For a blower in vacuum service, contamination is a potential problem that might only be caught once you see the product exiting the discharge pipe!

For a pressure blower, contamination of the blower could be from running the blower backwards, or a failed/missing check valve. Introduction of material in the blower can also damage the blower by causing an inertia event:

  • Spinning and then suddenly stopping
  • Resting and then suddenly starting
  • In both cases, energy can be directed in ways that are bad for the blower

An inertia event is usually when a blower is in operation and it comes to a sudden stop.  The force of the sudden stop/slow-down is often very detrimental to the blower, i.e., bent and/or broken shafts, twisted drive shafts, cracked headplates and cylinders.  Also, a blower can be spinning backwards from a faulty check valve and then be brought online, which applies enormous forces to the drive shaft as it has to overcome the inertia of the impeller spinning in the opposite direction.

Ingesting-Product-3The flyash has collected inside of the blower due to insufficient air filtration. The build-up on the back of the flange and at the headplate is common when material travels through a blower. The impellers will erode faster than the cylinder. Severe contamination of the blower can cause grooves at the cylinder headplate joints

Root Blower Help Line: Schedule Maintenance

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This summer remember to schedule maintenance so you can take a vacation, not your blower!

As summer comes into full effect, the conditions that your blowers operate under could be changing too, and this needs to be taken into consideration before you go on vacation. Make sure to have a clear schedule that other coworkers would be able to follow while you are away.
Your blower is a simple machine that just moves air, and it needs you to allow it do its work by:

  •  Changing your air filter before it is clogged
    – Call us for replacement air filters
    – Ask about restriction gauges to determine the best time to change your filters
  •  Aligning your drives and properly tensioning your belts
    – Call for belts, sheaves, bushings, and tension gauges
    – Ask about field service and training
  • Giving your process air a clear path to do the work it’s designed to do!
    – All valves fully open? They should be…
    – Pressure relief valve working? We have them…
    – Pressure gauges working? We have these too!

A quick review of your blower process could catch a problem before a breakdown!

Remember: air in, air processed, and air out!

Roots Blower Help Line: Standard Vibration Test for Blower Packages

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R&M preforms a vibration test for standard blower packages

This is a video of a full load vibration test of an R&M Equipment Company standard fully assembled blower package. We are using a Howden Roots 616 RAM blower and a 125HP drive motor operating at a system pressure of 10 PSIG. This test allows us to verify that all of the equipment is aligned properly, leveled and that the supporting structure is sufficiently designed to operate this equipment in a continuous application.

High vibration levels can lead to blower damage. It is important to have a well built package and properly install the package to maintain low vibration levels. It is also recommended to monitor vibration levels on a regular basis. Should you have a sudden or drastic increase in vibration, please contact us with questions as this indicates a problem.

This is one test we preform here at R&M, we can also preform mechanical run testing, noise level testing. We can also preform testing on site.

For a full speed & load vibration test, the procedure is as follows:

  • The design load will be created by a butterfly valve regulated to create the appropriate pressure drop.
  • The vibration levels for the blowers and motors will be measured on three planes horizontal, vertical, and axial under full load. The base will be measured in the vertical plane.
  • The blower recorded levels must meet the Roots vibration criteria for rotary lobe blowers. Vibration levels less than 0.45 is considered very good. Levels of 0.45 thru 0.62 are considered good. Levels of 0.62 thru 1.0 are considered satisfactory. Levels greater than 1.0 need review by the factory. If any measurements exceed the limits, adjustments will be made as necessary and the equipment will be re-tested until the specifications are met.
  • The NEMA criterion for vibration of un-loaded motors is 0.15in/sec. There are no criteria in NEMA for the vibration levels of loaded motors.
  • The base levels must meet the R&M standard level of 0.60″/sec.
  • Data recorded on the test form: T001