Dwyer Instruments, a US company, make a wide range of flow instruments
for air and liquids.  I am sure they'd have a web presence and may
have what you are looking for.

Regards,

Colin MacKinnon

 [ Dwyer Instruments, Inc., Michigan City, IN  See "Variable
 [ Area Glass Flowmeter" at http://www.dwyer-inst.com/
 [ Spencer Chase reported in MMD 960830 that the Dwyer Magnahelic
 [ suction gauge is distributed by W. W. Grainger Co.  -- Robbie