Technical articles, downloadable documentation and answers to the questions we hear most from the field.
The two most confused units in the blower world. SCFM is a mass flow reference at standard conditions (68°F, 14.7 PSIA, 36% RH). ACFM is the actual volumetric flow at the conditions the blower sees at its inlet. Sizing errors happen when the two are swapped.
Ask about thisFor rotary PD blowers, horizontal shaft orientation with vertical airflow is preferred. It keeps splash lube distributing correctly, drains water condensate naturally, and simplifies pipe routing.
Ask about thisNameplate gone? You can identify most Roots, Sutorbilt and Tuthill units from a handful of physical measurements — shaft height, casing bore, and rotor length. We keep a cross-reference chart at the ready.
Ask about thisBelt drive gives you speed flexibility and cheaper motor replacement. Direct drive gives you fewer parts to maintain and a quieter package. Here's how we help customers decide.
Ask about thisNot without a few checks first. Confirm the oil is at the sight-glass mid-point in the orientation the blower will operate in, verify the drive alignment and belt tension (or coupling gap for direct-drive), rotate the shaft by hand to confirm free movement, and bump the motor to verify direction. Only then bring it up to full speed against the inlet filter and discharge silencer in place.
The gear end takes ISO 220 rotary blower oil in most ambients (ISO 320 in high ambient, ISO 100 in cold service). The drive end is grease-lubricated — use Mobil Polyrex EM or an approved equivalent. Never mix greases and never over-fill; over-lubrication is the #1 cause of premature bearing failure.
Lock out the motor and try to rotate the input shaft by hand with a strap wrench. If it will not turn at all, either debris has entered the airend, timing gears have shifted, or a bearing has failed. Do not attempt to force it — contact our service team and we'll diagnose remotely before you ship it in.
Watch the differential pressure across the filter. As a rule, clean or change when the differential reaches 15 inches of water column. Running a plugged filter starves the blower, raises discharge temperature, and shortens bearing and gear life.
Small drops of grease under the drive end are normal — the seals are designed to purge slightly to keep the process side clean. A steady drip or oil (not grease) coming out is a different matter and should be inspected. Send us a photo and model number and we'll advise.
Send us clear photos of the airend from both ends, the drive shaft, and any visible casting numbers. Our team can identify almost any Roots, Sutorbilt, Tuthill (MD Pneumatic), Cycloblower or Duroflow unit from photographs, and we can walk you through a physical measurement if needed.
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(800) 955-6188Sizing & Packaging Blowers
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