Proper placement and use of fume hoods and blowers are important laboratory ventilation requirements. HEMCO offers the following suggestions to help in your laboratory layout. For technical support please contact HEMCO.
Laboratory Blower Recommendations
1. Blowers should be mounted on the roof in-order that
the ducting leading to the blower inlet is under negative
static pressure. If exhaust blowers are mounted inside
the building, all ducting connected to the blower outlet
will be under positive static pressure, if a leak were to
develop in the section of the duct inside the building,
toxic and or hazardous fumes could be forced out of
the ductwork and into that area of the building.
2. To achieve the lowest practical noise level in the
exhaust system, we suggest that the following
measurements be used when there is no conflict
with other specifications of the system:
a. Use vibration isolators or mounting blower exhaust
b. Install a blower fan that will deliver the correct CFM
and static pressure with the lowest practical impeller
wheel RPM. If possible, use a duct size large enough
to keep duct velocity under 1800 FPM velocity.
c. Use a flexible connection at the fan inlet to isolate
mechanical transmission of noise from the ducting
between the hood and the exhaust blower.
d. Exhaust blower system should be designed with the
fewest possible elbows or other fittings. Use radius
type elbows & avoid using square elbows. Use
gradual tapered transitions where necessary, & avoid
abrupt changes in configuration or cross sectional area.
3. When ordering an exhaust blower, specify the
orientation of discharge desired. Vertical up blast
discharge is the most common and will be supplied unless otherwise specified.
4. All fans are shipped with clockwise rotation when viewed from the motor end of the assembly.
5. For normal usage, the standard for both the blower housing and impeller wheel is epoxy coated.
6. Blowers used for hood exhaust at altitudes above
1,000 feet, may require a correction factor to
provide the correct CFM and static pressure.
Contact factory for details relating to your
Motor speed control can be used to manually adjust blower cfm. Adjustable speed control for 3-phase motors 3/4 to 10 horsepower at 230/460 volts and 50/60Hz. these drives provide high operation efficiency and constant input power factor throughout the entire speed range of 3 to 60Hz. Drives are rugged, reliable and backed by years of manufacturing and application experience in motors and controls. These drives are tailored to the variable torque loads in fans or fume hoods.1/2 -5HP 230V 3ph, 50/60Hz................................................Cat.No. 51402
Laboratory Polypropylene Fume Scrubbers
Laboratory Fume and Vapor Clean Aire Scrubbers
Scrubber systems offer high efficiency & minimal maintenance on meeting pollution control requirements.