Nutrient dosing · PR-PMP-001

Gravimetric pump calibration

Name: FlavoRotor
Brand: FlavoRotor

A complete channel-specific procedure for converting motor commands into measured liquid volume with uncertainty and drift.

Markdown JSONRevised 2026-07-26

In brief

A complete channel-specific procedure for converting motor commands into measured liquid volume with uncertainty and drift.

Principle

Each pump dispenses into a vessel on a calibrated balance. Mass gain is converted to volume using fluid density at the measured temperature. The test is repeated across channel, dose, speed, tube condition and hydraulic head.

C-1

V_i=\frac{m_{\mathrm{after},i}-m_{\mathrm{before},i}}{\rho(T)}

Delivered volume for repetition i.

ExplanationThe mass gained by the receiving vessel is converted into liquid volume using density at the measured temperature.

C-2

Q_i=\frac{V_i}{\Delta t_i}

Mean flow for repetition i.

ExplanationMean flow is delivered volume divided by run time.

The gravimetric chain follows traceable liquid-volume and uncertainty principles: balance performance, test-liquid density, evaporation, timing, repeatability and calibration state are recorded. Large published peristaltic-pump datasets show why repeated measurements and drift analysis are necessary, but their performance values are not transferred to FlavoRotor.

Test matrix

Factor	Levels
Channel	1, 2, 3, 4
Rotor speed	5, 15, 30 and 60 rev/min
Commanded dose	0.5, 1, 2, 5 and 10 mL
Repetitions	minimum 20 per primary condition
Fluid	deionised water and each representative stock class
Tube state	new, mid-life and replacement threshold
Hydraulic condition	minimum, nominal and maximum inlet head; installed outlet path
Direction	forward; reverse purge characterised separately

Calibration statistics

C-3

\bar V=\frac{1}{N}\sum_{i=1}^{N}V_i

Mean delivered volume.

ExplanationThe arithmetic mean combines all repeated delivery measurements.

C-4

\mathrm{bias}=\bar V-V_{\mathrm{set}}

Absolute systematic error at a test point.

ExplanationBias is the difference between the mean delivered volume and the requested volume.

C-5

\mathrm{CV}=100\,\frac{s}{\bar V}

Coefficient of variation for repeatability.

ExplanationThe coefficient of variation expresses repeatability spread as a percentage of the mean.

C-6

\mathrm{RMSE}=\sqrt{\frac{1}{N}\sum_{i=1}^{N}\left(V_i-V_{\mathrm{set}}\right)^2}

Combined deviation from the requested volume.

ExplanationRMSE combines all deviations from the requested volume into one error value.

Repeatability, bias, residual analysis and method precision are reported using declared statistical procedures rather than a single R² value.

Channel model

C-7

\hat V_j=a_jN_{\mathrm{cmd}}+b_j

First candidate model for channel j; residuals determine whether speed, pressure or nonlinear terms are required.

ExplanationThe first calibration model links command count to delivered volume; residuals show whether a more complex model is needed.

Predefined engineering acceptance gates

Metric	Gate for initial reservoir dosing
Relative bias	≤ ±3% for doses ≥1 mL within the declared range
Repeatability	CV ≤2% for doses ≥1 mL
Channel model	residual structure absent and R² reported, not used alone
Drift	≤5% before recalibration or tube replacement
Cross-channel contamination	none detected above method limit
Backflow/siphon	no uncontrolled transfer in the installed hydraulic range

These are FlavoRotor acceptance criteria, not claimed achieved performance. Published multi-channel pump data guide the method but are not copied as FlavoRotor results.

FlavoRotor design provenance

The system-specific configuration on this page is traced to the supplied FlavoRotor engineering records.

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