For pressures to 1,000 psig (69 bar)
Armstrong free-floating lever dual gravity drain traps are identical
to Armstrong’s 2-LD, 3-LD, 6-LD, 32-LD, 33-LD, and 36-LD, except float
weights are modified to make them suitable for draining water from a
light liquid. If you wish to use them for draining any liquid with a
specific gravity other than 1.00, consult the Armstrong Application
Floats for dual gravity drain traps are weighted with quenching oil,
which, in the unlikely possibility of float failure, may be dispersed
through the system. If this is a hazard, consult the Armstrong
Application Engineering Department.
NOTE: Armstrong can design dual gravity traps for venting light
liquids from above heavier liquids. Consult the Armstrong Application
Viscosity considerations for dual gravity traps
The operation of dual gravity traps depends upon a float that will
sink in the light liquid and float in the heavy liquid. When the
specific gravities of the two liquids are very close, the available
operating forces are, therefore, also very small. Viscous fluids may
impair the ability of the trap to respond to changing liquid levels.
Consult Armstrong’s Application Engineering Department if your
application involves fluids more viscous than 70 cs, which is
approximately the viscosity of a light machine oil.
Installation and Maintenance