Dresser 409 JH RCS whispair. 406 RCS H whispair. 
Dual 30 HP motors. 406 min-max is 145-583 cfm (4.13-16.5 cubic meters/min) @ 1750-4000 rpm on pressure
and 159-604 cfm (4.5-17.1 cubic meters/min) @ 1750-4000 rpm on vacuum. 
The 409 has 221-875 cfm (6.25-24.7 cubic meters/min) @ 1750-4000 rpm on pressure 
and 242-906 cfm (6.85-25.65 cubic meters/min) @ 1750-4000 rpm on vacuum. 
Includes a shell and tube heat exchanger used to cool down products that can become tacky when heated, 
with 250 psi (17.2 bar) max shell pressure, 150 psi (10.3 bar) max tube pressure and 350 Deg. F. (176 Deg. F.) max. operating temp. 
Unit is mounted on a common painted steel frame. 
Last used to convey sugar and wheat flour in a food operation.