Practical Pointers | Fives North American

NOZZLE MIX SYSTEMS

use a short nipple between the bleeder's "A" connection and the controlled air pipe (see page 9)

Bleeder set for 50% ‡

R M

A

air

16 osi

5D

3D

8 osi

4 pipe dia.

2 osi drop

10 pipe dia.

10 osi

8 osi

Gas/Air Ratio Regulator

8 osi

spring adjustment

USE OF A BLEEDER

The supply pressure (say 10 osi) minus pressure drop through the air/gas ratio regulator (say 2 osi) equals the available outlet pressure (8osi). The impulse pressure must be lowered to this value or less. The available outlet pressure (8osi) divided by the air pressure (say 16 osi) equals 50%; so the bleed should be set to give 50% or less of the air pressure as impulse pressure. Then 6 osi air will give 3 osi impulse; 0.5 osi air, 0.25 osi impulse; etc. The same is true for any selected percentage. As part of the lighting procedure, it will be necessary to open the limiting orifice (gas adjusting) valve wider than for cases where gas pressure equals air pressure. ± Several %'s are available by changing bleed orifices - see Bulletin 8654/55

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