This apparently simple question has a twist at the end when it refers to 'boxes' being conveyed. There is no information about the aspect ratio of the boxes, the spacing of the boxes, how they are oriented at the transfer point or are synchronised to merge and avoid clashes, so I believe the answer is indeterminate. The situation would seem to call for a 'meshing' device to control the release of alternate boxes and a spacing margin of safety, as they presumably cannot 'shuffle' in a converging path like cans or conventional particulate solids. ■

Transverse conveyor speed is indeed indeterminate and also immaterial.You need to consider box speed across the transfer table. You have not given any indication of the heights available and so it must be assumed that a transfer table helps.

There will have to be a couple of side walls and so there is no issue. Incoming boxes sit idle on the transverse rollers and on the transfer table until there is a gap in the main line. If the slopes are right and the box size spectrum is reasonable the incoming box holds back the mainstream until a gap develops to accommodate the incoming box. Slopes are the answer and must be very carefully calibrated. Similar impingement principles can be extended to belt conveying and the friction coefficient needs to be low.

Box and pallet handling is more widespread, sophisticated and competitive than bulk particulate handling and you will get a better idea by surfing websites more appropriate to your application. There are also Youtube videos showing animations of similar situations. ■

Hello,

This thread is of November 2015, so it is obvious that I am responding very late. However, I am considering that the information may be of some use to someone.

Two bagging machines operating in a synchronised manner, and then say discharge on their individual conveyor no. 1A and 1B. Then both are discharging onto third conveyor say conveyor no. 2. This can have 2 kinds of situation:

Situation 1: All 3 conveyors have a common speed such that conveyor 1A and 1B bags will have longer spacing. When these conveyors discharge onto 3rd conveyor, the spacing / pitch of the bags will become half. However, initially speed is chosen such that one bag will not lie on other bag. In your case, read box instead of bag.

Situation 2: Conveyor 1A and 1B have speed say 0.5 mps and conveyor 2 has speed say 1.0 mps. In this case, the spacing / pitch of the bags will appear same on conveyor 1A, 1B and 2.

I think such situation is likely to be quite common in fertiliser plant and cement plant.

Ishwar G. Mulani

Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 2012.

Author of Book: ‘Belt Feeder Design And Hopper Bin Silo’

Advisor / Consultant for Bulk Material Handling

System & Issues.

Pune, India. Tel.: 0091 (0)20 25871916

Email: conveyor.ishwar.mulani@gmail.com

Website: www.conveyor.ishwarmulani.com ■