Fan flow synchronizer

Abstract

The fan synchronizer is a small flow tube 5, 2″ IPS or smaller, connected between the supply fan 13 duct and return and/or exhaust fan 16 duct that allows flow through the tube 5 to issue a signal from an in line flow meter device 2 that will control the supply fan 13 and return/exhaust fan 16 to be synchronized to hold a set flow difference throughout the system flow range without series flow instability. The purpose is to maintain, in a variable flow system, a positive or negative building or room pressure difference to atmosphere, avoiding series flow instability of the fans.

1 . Synchronize and track return/exhaust fan  16  flow with supply fan  15  flow by sensing flow through a 2″ IPS maximum pilot line  5  and flow sensor  2  between the supply fan  15  discharge duct and the return/exhaust fan  16  inlet duct when static pressure controls supply fan  15  and variable flow system has a positive pressure to atmosphere. 
     
     
         2 . Synchronize and track supply fan  15  flow with exhaust fan  16  flow by sensing flow through a 2″ IPS maximum pilot line  5  and flow sensor  2  between the exhaust fan outlet duct and supply fan inlet duct when static pressure  10  controls the exhaust fan  16  and the variable flow system is controlled to negative pressure versus the atmosphere. 
     
     
         3 . Control room pressure positive to atmosphere by sensing flow through tube  5  flowing from room sensor  3  to atmosphere sensor  3  and air flowing into room from supply source  20  at a higher rate than controlled air leaving through the exhaust damper  22 . 
     
     
         4 . Control room pressure negative to atmosphere by sensing flow from atmosphere to room through tube  5  flowing from sensor  3  from atmosphere to sensor  3  in the room then out through controlled exhaust damper  22  at a rate higher than the air supplied by the inlet supply duct  20 .