Bulk-End Dump, Hoppers, Belly Dumps, Scales/Gauges

Thought I would start a discussion for us bulk haulers, about scales or gauges. How accurate are the "Load Leveling" air gauges? How would you really calibrate them?

In the short time I've been driving, while loading at various places, like the Salt Plant in Lyons, or grain elevators, I've heard drivers state their gauges are fairly accurate, and can tell within a few hundred pounds. Maybe they're using actual digital scales, don't know.

I have air pressure suspension gauges. I've been trying to get that "accuracy" when loaded. Most of the time when my front gauge reads 60 and my rear/trailer reads 70, my weight has been very close to 85.5k gross. This is having 24k loaded on the front, and the remaining in the rear, which would be around 27-28k. Doesn't seem like too much of a problem, and could probably be checked against a CAT scale. I might do this in the near future just to be sure.

Thursday I loaded rock first thing in the morning at our local quarry. While they have a loader operator load you, and his loader has scales, and he is very good, you weigh yourself, and prepare your own scale ticket, all hand written, no stamping. Well according to the scale, my gross was about 84k. My gauges however looked like it should have been an 85.5k load. Now the next load was salt at Lyons.

For bulk de-icing salt, you are loaded while sitting on the scale, from an overhead bin/chute. I was told that these are some of the more accurate scales that we load from. WRONG!! On Thursday I arrived after 3pm, when they change shifts. Since the de-icing salt has been very slow, they do not run more than one load point. Most of the time, I load out of Load Point #2. This time it was Load Point #1. They load me, up to 85.5k. I then go back to the main scale, where the BOL are done. Well they over-loaded me. There was about an 800# difference in the 2 scales. So they sent me to Load Point#2 to off-load some. After doing so I was weighed on LP#2's scale, which showed me to have a 85,480 gross. So I go back to the main scale, and It shows me to still be over by 20# (85,520).

My air gauges even with the additional 800# over, did not reflect any noticeable difference. I'm not placing much trust in the air gauges. Even though while empty they both reflect the same pressure, which they should.

For the most part, the routes I run do not take me across DOT scales. I've only had to scale 3x, two of them I was empty. The one time I was loaded, grossing 85,400 by the elevator's scale, and was ok going across the MO DOT scale at Harrisonville.

 

Mine are increments of 10.

 

Here's a pic of the "scales" (gauges) in my truck. As you can see they're Suspension Leveling gauges. The scale is PSI to the airbags. So how do you tell how much weight that's been added?



As you can see in the photo, both are registering around 60 psi. Now if the loader, which was being done by overhead bin, while I'm setting on a scale, loaded my trailer as I wanted, each increment would represent about 4k lbs. I had him load 24k in the front, and the balance (about 29k) in the rear, up to 85.5k GVW. If I remember correctly, I had around 52,000 net. My truck/trailer empty weight is around 32,200.