Air pressure discharge vehicles

Powdered limestone products are generally transported by air pressure discharge vehicles. Whiting and precipitated calcium carbonate are also dispatched in bags. 

Sheeted tipper waggons or covered rail hoppers are generally the most economical form of transport for lump and granular quicklimes which have been screened to remove the fines (e.g. < 5 mm particles). Air pressure discharge vehicles are used for fines and ground lime products and may also be used on product with a top size of up to 20 mm. Intermediate Bulk Containers are also used. 

Air pressure discharge vehicles are able to blow directly into the storage bunker, which should be as described in section 17.3.4 and fitted with a filter to remove dust from the conveying air. The filter should be weatherproof and watertight and should discharge the collected dust into the bunker. A pressure relief device should be fitted as well as the usual accesses and safety features. 

Hydrated lime is generally supplied to small users in paper sacks or intermediate bulk containers (IBCs or big bags ) of 0.5 or 11 capacity. Where larger amounts are used, the product is delivered in air pressure discharge vehicles (APDVs). 

Delivery costs often amount to 50 % of the ex-works price, depending on the distance and mode of transport. Screened products are mainly transported in bulk using tipper trucks, which are sheeted to exclude rain and to prevent dust emission. Ground quicklime and hydrated lime are transported in air pressure discharge vehicles. Such vehicles can also be used for screened products with a top size below 20 mm. Smaller quantities are packed in intermediate bulk containers of 0.5 or 11 capacity, and in paper sacks. 

Finely divided products, such as ground quicklime and hydrated lime, are loaded into air pressure discharge tankers for transport. A flexible chute is used, which fits the loading hatch of the vehicle, and incorporates an extraction hood connected to a vacuum filter system. The hood removes both displaced and conveying air emerging from the hatch. 

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