Their patent expired many years ago.

THey are in the rubber business. THey have been in the rubber busness for over 60 years. They owned a major rubber plantation in Liberia until the recent civil war decimated their installations. ■

Dear Mr. Khalid,

I do not have the factual history of patent made by Bridgestone. Possibly, they or a Japanese company sold their patent to Germany. Now a days there are many manufacturers of pipe conveyors and they can have their patent pertaining to the specialised features of their make.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Dear Mr Mulani

To the best of My knowledge Japan Pipe Conveyor was responsible for initial devlopment of pipe conveyor First pipe conveyor was installed in 79 and patented the pipe formation technology. Japan pipe conveyor sold its rights to bridge stone corporation . Bridge stone appointed licensees all over the world.Like Dosco , krupp Robins etc They sold pipe conveyors thru their licencees. Due to high price these conveyors could not be installed in developing countries, who could not afford them.

To the best of my knowledge Bridge stone licencees have to take pipe conveyor belt , pipe conveyor idlers, panels from Bridge Stone

In early ninetees patent rights of Bridge stone started expiring and other manufacturers who were having expertise in high capacity and long distance belt conveyors started developing pipe conveyors.

Now the market is very very competitive and many manufacturers started manufacturing pipe conveyor belt and new pipe conveyor suppliers have option to purchase belt from any of the reputed supplier and use their own make panel/idlers

A R SINGH ■

dear khalid, salam wale kum.

If your goodself will see/read first line written by hon. mr mulani,he himself has agreed that he does not has the facts,so the point raised by you about wrong information does not exists.

regards, anil seth ■

Dear Mssr. Mulani & Khalid,

Bridgestone did not give JPC patent rights to any German companies. THe German companies waited for the patents to expire.

As I have stated before in the forum, Conveyor Dynamics, Inc. (CDI) was contracted by Bridgestone in about 1992 to develop a rheology based pipe conveyor power formulation. THis work took about 2 years. To my knowledge, CDI is the only company to hold this technology.

Prior to this development, Bridgestone used a German based power equation for their pipe conveyor or JPC (Janpanese Pipe Conveyor) program or so I was told.

Dear Mr. Mulani please share with us the patentable features the German companies hold for pipe conveyors. ■

Dear Khalid,

Sentence 1: yes

Sentence 2: each have developed thier own ■

Dear Mr khalid

Pipe conveyor hose power calculation is not very big issue all pipe conveyor suppliers are having their own methods to calculate power ratings.

However in case of hgh capacity and long distance pipe conveyors you have to take expert advise. same is also applicable on belt conveyors

pl also note power in case of pipe conveyor depends on belt characterstics like regidity etc.

A R SINGH ■

Dear Sirs

If I could clarify some points regarding pipe conveyors and patents.

(JPC) Japan Pipe Conveyor company (Subsequently taken over by Bridgestone) developed the pipe conveyor system in the late 1970's with various patents being put in place in the early to mid 1980's these were for the system and the belting with expiry dates of 20 - 25 years.

In the early to mid 1980's Bridgestone issued licencee agreements to companies in various countries i.e. UK, Germany, Austria, USA, Italy, S.Africa.

Some of these still exist, some have gone, and some have been added.

Some still have a working arrangement with Bridgestone who's combined worldwide experience and reference list is by far greater than any other system of this type.

Paul Holt

Dosco Overseas Eng Ltd.

UK ■

Dear Paul HOLt

You are correct combined worldwide experience and reference list of bridge Stone is by far greater than any other system of this type.

I have seen M/s Koach have alone supplied more than 180 installations in world.To day if we consider one single manufacturer who have supplied more installations and who is having credit of suppling largest pipe conveyor installation

This is just for our knowledge

A R SINGH ■