Wouldn’t one by one online refer to batch system rather loss in weigh type? What if flow rate from ship loader is not constant? Error will creep back in the mind of the client.

If I am correct to assume hoppers are on load cells then I think it is a simple case of checking calibration of the load cells. Reputed supplier has noting to do with it, every load cell needs calibration and have to be recalibrated after certain time anyway as suggested by the supplier. Easiest way is to load the hopper with calibrated dead weights and read the display. If required then reprogram the controller. You will probably need a crane and some weights why trouble a consultant?

Success ■

Raw material is unloaded by ship loader and is loaded on Jetty conveying system by ship loader.

Is it a ship-unloader.

In a commercial transaction involving shipping. Quantity written in Bill of Lading (certified after draft survey) is the one acceptable for transaction. The wieghing systems on loader conveyors (for loading a ship) / conveyors starting from unloader hoppers (for unloading a ship) can only be taken as confirmatory checks.

Copper concentrate is an expensive commodity and 0.5% inaccuracy means a deviation of 300 T in a 60000 T shipment. ■

I agree with both Lyle and Mantoo. Both methods of checking the calibration are valid. No need for a consultant. For the weighed load check use a validated weigh bridge, for the static weights used validated static weights. Couldn't be simpler really. If your customer really wants to spend money on a consultant then so be it, they can pay me to do it!

Jon Scarrott ■

Reg : Online Weighing hopper

For this application, use 3 load cells for bin measurement. The discharge of the bin through weigh Belt (measuring unit) arrangements so that u can know the exact material discharged from the bin. This system gives the accuracy up to 0.5%.

Ensure the all the mechanical arrangements of the weigh belt should be mounted on the bin.

Thanks and Regards

S.Ethiraj

Senior Executive – Service

Transweigh India Ltd

Mumbai – India. ■

I side with Vinayak. Why are you using a scale for accuracy in billing. All scales have a margin of error. Bulk commodities in large quantities that are being transported by ship should always be invoiced according to draft survey. Scales on the unload system are only to confirm unload rates. Sounds like you need a surveyor rather than a consultant. ■

Dear Mr. A R Singh

What ever the technical discussions I am accepted, but I understood your requirement. Your asking accuracy range is very difficult (0.01) may be the first cross checking time it will come but there is no guarantee for long term.

As per your reply you are using 3nos load cell, but how you are discharging the material from the bin. Like this system you will get the measurement based on discharge only.

This is possible to implement (on line hopper weighing) but the accuracy will come 0.5% only.

Thanks

S.Ethiraj ■

Dear Mr.Singh,

If we can inspect the system we may offer some solution.Kindly give your contact details to our email Id

Thanks & regards

V.Sundar

newtonws@gmail.com ■

Originally Posted by arsingh

Dear Sir

One of our clients is looking for reputed consultant to review accuracy of on line weighing hoppers.

Raw material is unloaded by ship loader and is loaded on Jetty conveying system by ship loader. At the Discharge point of Jetty conveyor two weigh hoppers are provided for on line weighing one by one . Weighing system is supplied by a very reputed supplier.

Raw material weighed is copper ore and our client have to pay for ore as per weight indicated by weighing system.

Our client doubts about system accuracy and looking for reputed consultant in weighing field

A R SINGH

Dear Friend,

I think it will better that you use a belt scale instead of bin scale, you just need to interlock conveyor drive with belt scale, we use it in a sand refinery plant and are sure about that system. ■