RSP Design
Free engineering tools

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Quick calculators our engineers use every day, for hold tubes, line velocity, tanks and standardization. Results are estimates for planning, not a substitute for a stamped design. Need the rule behind the number? Search the PMO →

Calculator 01

HTST hold tube

Sanitary hold tube length, including the 180° return bends. Flow enters at the bottom and leaves at the top, sloping up ¼" per foot.

See it on the plant tour: HTST pasteurizer →
gpm
sec
ft

Return bends figured at a centerline radius of 1.5 × OD; the PMO counts fitting centerline length as straight pipe. The ×2.0 basis matches the PMO HHST formula L = 588·Q·t/D². The 161°F / 15 s minimum and ¼"/ft upward slope are from the PMO. Search the PMO for holding tube →

Total hold tube length (centerline)–ft
Velocity
–
Passes
–
180° bends
–
Last pass
–
Hold volume
–
Min rise
–

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Calculator 02

Velocity + CIP check

Line velocity, pressure drop through sanitary tube and fittings, and whether CIP flow meets 5 ft/s.

See it on the plant tour: CIP silo wash →
gpm
ft
qty
qty

Sanitary sweep fittings figured at K = 0.30 per 90° elbow and 0.45 per 180° return. Valves and equipment are not included.

Line velocity–ft/s
Total pressure drop
–
Straight tube
–
Elbows + returns
–
Reynolds no.
–
Min gpm @ 5 ft/s
–
Gal per 100 ft
–

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Calculator 03

Tank volume

Vertical cylindrical tank or silo, straight side only.

See it on the plant tour: raw milk silos →
ft
ft
80%

Milk is figured at 8.6 lb/gal. Heads and cones add volume and are not included.

Volume at fill level–gal
Full capacity
–
Milk at level
–
Gal per inch
–

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Calculator 04

Standardization

How much cream and how much milk to blend to hit your target fat.

See it on the plant tour: separator + standardization →
%
%
%
lb

Example: 40% cream + 3.5% milk to make 10.5% half & half. The target has to fall between the two. Gallons use 8.6 lb/gal.

For a 10,000 lb batch you need
Cream (A)––
Milk (B)––
Ratio A : B
–
Cream share
–
Fat in product
–

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Calculator 05

Quick conversions

Type in either box. Milk is figured at 8.6 lb/gal.

See it on the plant tour: raw milk receiving →

Handy plant-floor numbers: 161°F = 71.7°C · 45°F = 7.2°C · 1 bar = 14.5 psi.

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These tools give planning estimates only. Final design, sizing and regulatory acceptance should be confirmed by a qualified engineer and your regulatory agency.