Free-Floating Lever Dual Gravity Drain Traps 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 and 6-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 Engineering Department. 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 Engineering Department 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.