Closed Loop Slug Dose Volume

Also known as slug dose · one-shot dose

Vp=CVsρwρpV_p = \frac{C \, V_s \, \rho_w}{\rho_p}

Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!

Learning zone

Closed loops are not fed continuously — they get slugged. You want a target ppm in the loop, you know roughly how many gallons the loop holds, and the drum in your hand is a liquid whose label gives a density in pounds per gallon. Convert the required mass of product to a volume you can actually pour: 200 ppm into 1000 gallons needs 200 × 0.001 × 8.34 = 1.67 lb of product, and at 9.5 lb/gal that is 0.176 gal — about 22.5 fluid ounces. Measure it in a graduated pitcher, not by eye.

Chemical density is the part people skip. Nitrite and molybdate inhibitors commonly run 9.5–10.5 lb/gal, glycol-based products near 8.6, and concentrated caustic 12.7 — assuming water density can put you 25% off. Field practice: pour the slug into a bypass feeder (a pot feeder), open the isolation valves, and give the loop at least three full turnovers before you test. Testing ten minutes after dosing produces a beautifully wrong result and a second unnecessary slug on top of it.

Closed Loop Slug Dose Volume
Vp=CVsρwρpV_p = \frac{C \, V_s \, \rho_w}{\rho_p}
Where
  • VpV_p= Product volume to add
  • VsV_s= System volume
  • CC= Target concentration
  • ρp\rho_p= Product density
Missing one of these? Work it out first, then come back