Bulk Tanker Discharge (Flour)

WJB Stephenson - GWF, Australia
(not verified)
Posted in: , on 1. Oct. 2002 - 11:30

The question I wish to pose concerns the problem which we, and I'm sure many other operators of bulk tankers encounter when the load transfer is completed. The product in question is flour and typically we are delvering to a bulk storage bin at a Baker customer. At the end of the transfer when there is no more flour to discharge, the resistance in the conveying line reduces dramatically and the compressed air in the tanker discharges to the bin at a much increased rate. This increase in air flow temporarily overloads the bin filter and pressurises the bin often causing the emission of dust to atmosphere.

One solution is to increase the size of the filter on the bin but if you have many customers this is an expensive exercise.

I feel that there is scope for the development of an airflow control valve that responds directly to blowline pressure and maintains the flow of air from the tanker at the normal conveying air flow rate.

Is it possible that such a valve has already been developed? Or, is there another solution?

Re: Bulk Tanker Discharge (Flour)

Posted on 1. Oct. 2002 - 10:58

Dear Mr. Stephenson,

The flow control valve that you need is a standard for dense phase conveying systems. You can get it from several vendors but if you need my recommendation please let me know.

This control valve has a PID loop that controls the flow of gas into the conveying line based on the conveying pressure.


Amrit Agarwal (Tim)

Pneumatic Conveying Consultants

Patrick Cole
(not verified)

Tanker Discharge

Posted on 9. Oct. 2002 - 06:42

We have had the same over pressure problem discharging sugar tankers in Victoria Auistralia. The silos were fitted with 10mbar explosion vents which where burst by the tanker over pressure in the silo at the end of discharge.

We were unable to convince the trucking company who own the truck to fit valves to the truck conveying system.

We over-came the issue by fitting a fast acting butterfly valve in the conveying line to the silo from the truck this valve was activated directly (not going through a control system) by a pressure transduce fitted to the silo. This also cut the power to the trucks blower. The drivers soon discovered that they need to control the pressure or the power is cut to the blower.

If you need further information I can advise you of our engineer in Sydney who hanled this project, contact details.