Fume Hood Exhaust Blowers

HEMCO offers a complete line of belt-drive and direct-drive exhaust blowers designed specifically for laboratory environments. These blowers are chemical resistant and available in both standard and explosion-proof models to safely remove hazardous fumes and maintain proper airflow.

Blower Types

Belt Drive Blowers

Standard (STD) belt drive steel blower and impeller wheel are epoxy coated for superior chemical resistance. Explosion-proof blowers (EXP) have epoxy coated, non-sparking aluminum impeller wheel. V-belt drive and adjustable pulleys permit field balancing. Seven discharge positions to suit installation. Weather housing is furnished. Motor has thermal overload protection. Specify: 115 V single phase, 230 V single phase, 230/460 V three phase or 208 V (consult factory). 1 year manufacturer’s warranty.

Available in 115V single phase, 230V single phase, 230/460V three phase, or 208V (consult factory).

Catalog Number and Static Pressure
cfm	A Inlet Diameter	B Outlet Size	1/2” Static Pressure			3/4” Static Pressure			1” Static Pressure			1 1/2” Static Pressure
cfm	A Inlet Diameter	B Outlet Size	HP	STD	EXP	HP	STD	EXP	HP	STD	EXP	HP	STD	EXP
296	8 7/8”	10 1/8” x 4 1/8”	1/4	51701	51801	1/4	51702	51802	1/4	51703	51803	1/4	51704	51804
474	8 7/8”	10 1/8” x 4 1/8”	1/4	51705	51805	1/4	51706	51806	1/4	51707	51807	1/2	51708	51808
652	8 7/8”	10 1/8” x 6 3/8”	1/2	51709	51809	1/2	51710	51810	1/2	51711	51811	1/2	51712	51812
800	8 7/8”	10 1/8” x 6 3/8”	1/2	51713	51813	1/2	51714	51814	1/2	51715	51815	3/4	51716	51816
914	9 7/8”	11 1/2” x 8 1/4”	1/2	51717	51817	3/4	51718	51818	--	--	--	--	--	--
1044	9 7/8”	11 1/2” x 8 1/4”	1/2	51719	51819	1/2	51720	51820	1/2	51721	51821	--	--	--
1175	9 7/8”	11 1/2” x 8 1/4”	1/2	51722	51822	1/2	51723	51823	3/4	51724	51824	--	--	--
1240	9 7/8”	11 1/2” x 8 1/4”	1/2	51725	51825	1/2	51726	51826	3/4	51727	51827	3/4	51728	51828

Direct Drive Blowers

Direct drive steel blower and impeller wheel are epoxy coated for superior chemical resistance. Explosion proof blowers have epoxy coated non-sparking aluminum impeller wheels. Motor is 115V, 1 phase and has thermal overload protection. 1 year manufacturer’s warranty.

Available in 115V single phase, 230V single phase, 230/460V three phase, or 208V (consult factory).

Catalog Number and Static Pressure
A Inlet Diameter	B Outlet Size	HP	STD	EXP	1/4” SP	1/2” SP	3/4” SP	1” SP
A Inlet Diameter	B Outlet Size	HP	STD	EXP	cfm	cfm	cfm	cfm
6”	7” X 4-3/8”	1/6	51177	51178	565	515	440	300
8”	8-3/4” X 5-7/16”	1/3	51179	51180	935	875	800	712
9”	10-1/8” X 4-1/8”	1/2	51181	51182	1050	980	920	850
9”	10-1/8” X 5-1/8”	3/4	51183	51184	1260	1220	1180	1100

Polypropylene Belt Drive Blowers

High efficiency impellers produce low power consumption, reduced operating costs, and quiet operation. 20 forward curved blades in fire retardant polypropylene. Non-sparking and chemical resistant for hostile or hazardous environments. Non-static and oil resistant V-belt with cast iron pulleys and adjustable tensioning. 1 year manufacturer’s warranty.

Available in 115V single phase, 230V explosion-proof non-sparking. Other three phase options available.

Catalog Number and Static Pressure
cfm	A Inlet Diameter	B Outlet Diameter	0.5” Static Pressure HP			0.75” Static Pressure HP			1.0” Static Pressure HP
cfm	A Inlet Diameter	B Outlet Diameter	HP	STD	EXP	HP	STD	EXP	HP	STD	EXP
400	6”	6”	1/4	51450	51850	1/4	51460	51860	1/4	51470	51870
800	8”	8”	1/4	51451	51851	1/3	51461	51861	1/3	51471	51871
1000	8”	8”	1/2	51452	51852	1/2	51462	51862	1/2	51472	51872
1200	10”	10”	1/2	51453	51853	1/2	51463	51863	1/2	51473	51873
1600	10”	10”	1	51754	51854	1	51464	51864	1	51474	51874

Variable Speed Control

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, 50/60 Hz
Cat.No. 51402

Blower Selection Guide

When selecting an exhaust blower for your laboratory ventilation system, consider the following:

Required airflow (CFM) — determined by fume hood size, sash opening, and face velocity requirements
Static pressure — based on duct length, diameter, number of fittings, and total system resistance
Duct size and layout — longer runs and more elbows increase resistance and require a larger blower
Chemical exposure — corrosive environments require polypropylene or epoxy-coated construction
Explosion-proof requirements — flammable materials require non-sparking, explosion-proof models

Installation & Design Recommendations

Mount blowers at the end of the duct system, typically roof-mounted, so ducting runs under negative static pressure. If a blower is mounted inside the building, any duct leak on the outlet side could force hazardous fumes into the building interior.
Keep duct runs as short and straight as possible. Size duct diameter to keep velocity under 1,800 FPM to reduce noise and static pressure.
Select a blower that delivers the required CFM and static pressure at the lowest practical impeller RPM to minimize noise.
Use vibration isolators when mounting blower assemblies to minimize noise transmission.
Use a flexible connection at the fan inlet to isolate mechanical noise from the ductwork.
Design the exhaust system with the fewest possible elbows. Use radius-type elbows and avoid abrupt changes in cross-sectional area.
Blowers at altitudes above 1,000 feet may require a correction factor. Contact the factory for details.