Refractometric and Gravimetric Monitoring of Cold Pad Batch Alkali Ratios
Refractometric and gravimetric tracking stabilizes cold pad batch alkali ratios, preventing reactive dye hydrolysis and securing shade repeatability.
Baumé Hydrometer Scale
Density Measurement
Relative density scales provide a standardized method for determining the concentration of liquid chemicals based on the buoyancy of a weighted glass float. The baumé hydrometer scale allows mill operators to quickly check the strength of acids and alkalis without complex laboratory equipment. It relates the specific gravity of a solution to a simplified degree reading.
Mechanical Function
Buoyancy forces acting on a calibrated glass spindle cause it to sink to a specific depth corresponding to the liquid density. When using the baumé hydrometer scale, the user reads the value at the meniscus level where the liquid surface meets the graduated stem. Higher concentrations of caustic soda result in a higher reading as the liquid becomes more dense and supportive of the float.
Temperature Correction
Thermal expansion changes the volume of a liquid and therefore affects its measured density. A baumé hydrometer scale is typically calibrated at a specific reference temperature such as 15 or 20 degrees Celsius. To obtain an accurate reading in a hot dyeing environment, the operator must apply a correction factor or cool the sample to the calibration temperature.
Neglecting this adjustment leads to pronounced errors in chemical dosing.
Process Integration
Rapid testing of mercerising baths and bleach liquors ensures that the chemical concentration stays within the limits required for effective fibre modification. Monitoring the baumé hydrometer scale during the mixing of bulk chemicals prevents the use of overly dilute or dangerously concentrated solutions.