Measuring Load Birdsboro Leveler

[AWeigel]

Hi, My name is Andrew, I work at a steel mill in Coatesville PA. I'm looking into measuring load in the housing of a 5 over 4 Birdboro Plate Leveller. I imagine I could place a strain gauge on each post of the leveller housing to do this. This strain gauge must talk to a PLC so that we can record the data and continuously monitor. The seperating force on the leveler can be ~10 million pounds.

Another way to do this would be with load cell type devices backing up holding mechanism for the rolls that work on the steel plate.

The idea of this leveler is to take out shape defects in 1-4inch thick plate steel by yielding it upwards and then back downwards gradually less and less untill flat.

My question is where can I buy a strain gauge or load cell for this application? Thanks

 

[IceStationZebra]

First, a strain gage does not measure force directly. You don't buy a strain gage rated for X lbs. What you are measuring is how much the piece of steel is stretching. You would need to gage a piece that doesn't have much overdesign to get a reasonable resolution.

Another problems with strain gages is going to be the adhesive. You didn't mention if this is done hot or cold - but most of the long term and especially high service temp adhesives require elevated temperature cures. Basically you put the part into a heat treat oven for several hours. My very quick check of Vishay showed the highest adhesive service temp to be 700°F, but I bet there are higher temp adhesives available for use in turbines, etc.

I only know of 3 companies that make strain gages - Vishay, HBM & Kyowa. Omega sells Kyowa in plain packaging.

A load cell is basically several strain gages (usually a bridge) applied to a specially designed part that maximizes resolution and prevents any side loads from influencing the reading. Load cells come in several "standard" packages but most manufacturers would be willing to custom engineer a cell for your machine. As for a manufacturer just google it and you will find a couple dozen.

In my opinion the load cell is by far the best route for dependability and resolution. With either route you can amplify the bridge output and feed it into your PLC.

ISZ

 

[Compositepro]

On such a large machine your best approach is probably to strain gage appropriate parts of the machine and calibrate them for load. Any load cells would probably have to be custom made and would be much more difficult to install. This approach is not unusual on large presses.