Practical Pointers | Fives North American

NOZZLE MIX SYSTEMS

INSTALLATION FOR NOZZLE-MIX BURNERS

1. Install a limiting orifice valve between the regulator and burner. 2. If the minimum gas inlet pressure exceeds the maximum air pressure by 2 or more osi, simply cross-connect the regulator's vent to the main air line downstream of the control valve, as in Figure 3.

5 pipe dia. minimum

3 dia. min.

air

Control Valve

Limiting Orifice Valve impulse line

shutoff

Nozzle Mixing Burner

Air/Gas Ratio Regulator

Figure 3

3. If the minimum gas pressure at the regulator inlet is not at least 2 osi more than the maximum air pressure available at the burner, then a bleeder must be installed in the air pressure impulse line, as shown in Figure 4, with the amount of bleed set so that maximum impulse pressure is 2 osi less than the gas inlet pressure. (See page 34 and the Bleeder bulletin) This arrangement should be used only when combustion chamber pressures are atmospheric (open burner). 4. If gas and air pressure are not known, make a "trial and error" setting of the bleeder by lighting the burner and bringing it to high fire as described in step 3. Then successfully reduce the impulse to the regulator by means of a bleed until you find a bleeder setting that produces an effect on the flame. This is the correct bleeder setting for all firing rates. Readjust the limiting orifice gas valve. (If gas pressure is not constant set the bleeder for the next lower impulse pressure)

† Or pressure drop for which the regulator size was selected.

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