The Effect of Inclined Suction Nozzles on Vaccum Pneumatic Conveyor System Performance

Suction nozzles have been used for many years as the entraining device for the vacuum pneumatic unloading of bulk commodities from the holds of ships of all sizes. Much research work has been undertaken to improve the performance of these devices when used in a vertical attitude. However, the operation of these nozzles is often at an angle other than vertical due to the way in which the devices are manhandled. This paper presents the findings of an initial programme of work undertaken to assess the effect on the performance of vacuum pneumatic ship unloaders when the suction nozzle is presented to the material to be off-loaded at an angle inclined to the vertical. A range of products have been tested to assess whether product characteristics have an effect on the sensitivity of the vacuum pneumatic conveying system to the nozzle angle.