Startups can be Absolute Hell on Inline Instrumentation

Here’s something you may have experienced before. 

You’ve been down for your scheduled shut down and it’s time to start the process back up.  As the pumps start to circulate, you hear all of that awful knocking as the lines fill and stock starts to move again.

All of a sudden, some of your inline consistency instrumentation goes dead as a doornail.  You pull the sensor out of the line and notice that the sensing element has been bent, or has been completely sheared off.

So what happened? 

Most likely, your inline consistency sensing element just got nailed with a slug of stock that had been dewatering while sitting in the line during your downtime.  At start up, that dewatered slug – or log - started flying down the line as the process was coming up and slammed into your sensor at light speed.

It’s as if you just had a sledge hammer hit your instrument.  No wonder the sensor got damaged, huh?

So, now that you know that, how do you prevent it from happening again?

Here are a couple of ideas:

Install breaker bars both upstream and downstream of your sensor body.  Breaker bars are pieces of dumb metal – ours are cylindrical – that will hopefully break up those dewatered slugs of stock before they slam into your sensor.  It doesn’t work all of the time, of course, but it will work most of the time.  Breaker bars are cheap insurance that should be installed in front and back of every inline sensor in your mill.

By the way, we keep a good supply of these in stock ready to go at a moment’s notice.

A better idea is to install one of our C5000 retractable consistency sensors instead of the one you are currently using.  The C5000 sensor body was designed to be pulled out of the line so that it could be hot swapped while the process is active.  It can also be pulled out of the line during a start up so that dewatered slugs of stock will pass by harmlessly.  The sensing element can then be reinserted in the line once things settle down.

Nifty idea, that.