Batch Yarn as it leaves winding

Batch Mass kg

Regain as Wound %

Low, because spinning runs air-conditioned and dry

Target Regain %

Standard Regain %

The trade convention for this fibre. Cotton is 8.5

Steam & Value What it costs and what it is worth

Steam per kg of Moisture kg/kg

Includes heating the yarn and the chamber losses

Steam Cost cost/kg

Yarn Price cost/kg

Weight Gained

— kg

Moisture restored to the batch

Mass, Steam & Value

Oven-Dry Mass: — kg
Mass at Target Regain: — kg
Mass at Standard Regain: — kg
Weight Gain: — %
Regain Headroom to Standard: — %
Further Mass Available: — kg
Moisture Added: — kg
Steam Required: — kg
Steam Cost: — cost
Value of the Weight Gained: — cost
Net Gain per Batch: — cost

Regain is moisture on OVEN-DRY weight, not on the wet weight, and the distinction matters at every step here: 8.5 percent regain is 7.83 percent moisture content, and a mill that treats the two as interchangeable will consistently over- or under-shoot its target. The whole calculation runs through the oven-dry mass for exactly that reason. Conditioning to the standard regain is legitimate and conventional; conditioning ABOVE it is not, and the practical limit is not the arithmetic but the buyer, since a batch invoiced above standard regain will be adjusted at test and may attract a claim. The headroom figures are given so the distance to that line is visible, not as a target to reach. Moisture also does not stay where it is put: yarn conditioned to 7.5 percent and stored in a dry warehouse will drift back down over weeks, so the gain is realised only if the yarn is despatched reasonably promptly, and the twist setting - which is the technical reason for conditioning - is the part that persists. The steam figure covers the chamber and its losses but not the vacuum pump, and cycle time rather than steam is usually what limits throughput on a conditioning plant.

Yarn Vacuum Conditioning: Regain, Weight and Steam — free, with the formula and a worked example, at Textile School.