TYPES OF VACUUM BLOWERS

page 4, Vacuum Blowers

There are many types of vacuum pumps on the market to choose from. Vacuum blowers are a must to consider in CNC vacuum table applications where a large volume of air is required.

Positive Displacement Blowers:

Like the rotary vane pump the motor can be either direct drive or belt driven.

Instead of carbon impeller blades it has two rotors that rotate in opposite directions.

When the rotors pass the air inlet it captures air from the blower housing and sends compressed air out the exhaust vent in the process of creating the necessary vacuum. The sudden release of compressed air creates significant noise. This is one of the really large disadvantages of using Vacuum blowers.

Typically positive displacement vacuum blowers have noise levels in excess of 90dB and require some consideration in creating sound enclosures to bring this down to acceptable industrial levels.

Rarely can these blowers produce more than 15"Hg, but produce large volumes of air flow for flow-through MDF vacuum tables.

Regenerative Blower:

The motor either directly or belt drives a pump impeller drawing air in one side and exhausting out the other side to create a vacuum. The design does not allow for a perfect fit between the impeller blades and its housing so some air pressure is lost in the process, creating less than a prefect vacuum.

These blowers cap out at about 11"Hg but do generate a large volume of air flow like the positive displacement blowers. Great for holding down large sheets with less challenging clamping requirements, like thin wood veneers.

Maintenance is minimal, but noise is a big issue.. ask for a decibel rating for the blower that you are considering. Remember that 60 dB is human voice and say 85dB is the maximum sound level a human can safely tolerate.. but then even at this level your lab our council would expect employees to use hearing protection.

Now although cnc vacuum tables are the top of the line way to go you for many applications, there are situations where you may want to consider T-slot or T-track table options or maybe a hybrid systems that optimize hold-down devises with the integration of both technologies.

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