1
Eclipse ThermJet Design Guide No. 205, 3/5/07
High/low air & gas control (pulse firing)
A burner system with high/low control gives a high or low fire
input to the process. No input between high and low fire is
possible.
1. Air
Low fire:
A control input closes the solenoid valve
4
. As a result
the CRS valve
5
quickly moves to low fire.
High fire:
A control input opens the solenoid valve
4
. As a result
the CRS valve
5
quickly moves to high fire.
2. Gas
Low fire:
A control input closes the solenoid valve
1
.
Low fire gas passes through the butterfly valve
3
.
High fire:
A control input opens the solenoid valve
1
.
a.
b.
a.
b.
NC
Automatic
shut-off by
zone
NC
Automatic
shut-off at
the burner
P
to other Zones
to other Zones
to other Burners
Main gas
shut-off
valve train
to other Burners
➊
➋
➍
➌
➎
to other Zones
to other Zones
Main gas
shut-off
valve train
to other Burners
to other Burners
➊
➋
➍
➌
➎
P
P
Main gas
shut-off
valve train
➊
➋
➌
➍
➎
If fast high/low control is not necessary, the CRS valve can be
replaced with a two-position automatic butterfly valve.
Multiple burners
Automatic shut-off by zone
Single burner
Multiple burners
Automatic shut-off at the burner
Figure 3.3:
High/Low air & gas control (pulse firing)
Step 2:
Control Methodology
(continued)
