**Relative Humidity in Spinning Mill:**

The relative humidity is the ratio of the amount of water vapour present in a unit volume of air to the amount of water vapour required to saturate a unit volume of air under the same temperature and pressure. This is expressed as a percentage. Humidity is absolute terms is the amount of water vapour present in a given of air. In yarn spinning mill must has to maintain relative humidity. In case of low relative humidity fly dust produced then production will decrease. If relative humidity becomes high then production will also decrease. So, maintaining optimum relative humidity is one of the major tasks for a successful spinner. In this article, I will discuss relative humidity for example.

**How to Maintain Relative Humidity in Yarn Spinning Mill**

Moisture regain is normally calculated as a percentage of the moisture contained in the material on its oven-dry or bone dry weight.

Moisture content is the amount of moisture contained in the material and is expressed as a percentage of its original weight.

A woven dry or bone dry cotton when left in standard conditions of relative humidity and temperature, namely 65% and 68’F respectively (as per UK and USA and continent) is supposed to have moisture regain of 8 ½ %. India has a slightly different standard because of the general weather conditions.

…………………………………Original weight – Oven dry weight

Moisture regain% = ………………………………………………………….. ×100

…………………………………………….Original weight

Conditioned weight = Oven dry weight + 8 ½ %

…………………………………….Original weight – Oven dry weight

Moisture content% = …………………………………………………………… × 100

…………………………………………………..Original weight

**Mathematical Problems and Solutions:**

**Mathematical Problem no: 01**

A sample of 110 grains of cotton is found to have an oven-dry weight of 100 grains. Calculate the moisture regain, moisture content and conditioned weight of the cotton?

**Solution:**

………………………………110 – 100

Moisture regain = ……………..……… × 100

……………………………………100

= 10%

**Read More: Relation between Moisture Regain and Moisture Content**

………………………………..110 – 100

Moisture content = ……………..……… ×100

…………………………………….110

= 8.09%

Conditioned weight = 100 +8 ½ %

= 100+8.5

= 108.5 grains (ANS.)

**Mathematical Problem no: 02**

A sample cotton yarn piece of 325 yards has a bone dry weight of 40 grains. Find the conditioned count of the yarn i.e.After the yarn conditioned.

**Solution:**

Conditioned weight = 40 + 8.5%

= 43.4 grains

Conditioned count = (7000 × 325 ) ÷ (840 × 43.3)

= 62.4 nearly (ANS.)

Author of this Article:Amit Kumar DasFounder of "টেক্সটাইল ম্যানিয়া" Blog Pabna Textile Engineering College, Pabna, Bangladesh Cell: 01770 456240 Email: [email protected]