After opening the fibres in the blow room, the stock fibre is pneumatically transported to the carding machines (cards). Carding machines align the fibres and create a loose cord of fibre known as sliver. Then, the sliver is delivered to the spinning process for twisting into fine yarn. Carding machines generate high volumes of fibre and dust, particularly from raw cotton. They require specific suction directly connected to each machine in order to operate properly. Modern cards can process up to 500 lb. ( kg.) /minute of raw cotton and may generate 5 to 7 lb./ minute of waste dust.
Dust from raw cotton is known to be highly dangerous to humans and has proven to cause lung disease over time. Filtration system for this process must be highly efficient in removing the micro dust before any air is returned to the space occupied by personnel. The suction pressure level must be considered in the design of the air filtration system.
Luwa applies the Preseparator as the first stage of filter due to the high load of fibres from carding. The LDF rotary drum filter (or alternately the MCV or APF compact filters) for final stage filtration. The FDF Fine Dust Filter and WSA waste separator are applied for waste dust removal and fibre reclaim. A Pre-Filter is used to recover the fibres and a Fine Filter is used to filter the dust, this configuration is used for all kind of Fibres.
The Luwa Air Washer is applied for controlling temperature and humidity. Luwa B600 axial flow fans are used for primary air movement with ducting used for distributing air overhead and for the suction from cards since return air is heavily laden with fibre and dust. Normally there is sufficient suction from the cards to provide all the return air to the filters and meet the air conditioning requirements.
