Belt(s) won’t run? I’ll bet it’s not the pump.

Belt(s) won’t run?  I’ll bet it’s not the pump.

 1 of 3 – Mechanical

This is the first of three articles about Telebelt belt-related problems.

From time to time, I get calls involving a belt that won’t run, or runs very slowly.  The call I like the least is, “My feeder (or main) belt quit running.  I replaced the pump, but it still won’t run.”

With over 800 Telebelts in the field, we are looking at more than 2,100 piston pumps.  We don’t hear of pump failures very often.  Even if we go back to the Super Swinger 105s, of the early 90s, many are still running original pumps.

So, again, I’ll bet it’s not the pump.

Rule # 1 – Check to see if it will run with manual control.  If it will, the problem is probably electrical or in the radio.  If not, it’s mechanical or hydraulic.

Things that stop belts: 

  • Mechanical problems
  • Electrical problems
  • Hydraulic problems
  • Truck or engine failure.  This is beyond the scope of this series.

Let’s deal with mechanical problems, since they are the easiest to spot.

Are the PTO shafts turning? 

  • Actually look at them.  I once spent an hour on the phone with an operator who has just moved and set back up and his belts wouldn’t work.  I finally got him to look under the rig, where he found a pump drive shaft lying on the ground.
  • Is the PTO engaged?  Snow and ice can jam a PTO linkage.  Pins can fall out.  Air lines can leak.  PTO shaft gears can strip.

Do the hoses jerk, like there is pressure?  Does the belt move a little?  Put a pressure gauge on the test port.  If there is 280 bar, and nothing is moving, look for:

  • A seized 5” pulley
  • A seized feeder drive pulley
  • Over-tensioned scraper – Yes, that can stall a belt.  It can also stall a belt that is heavily loaded.
  • Rocks packed at tail pulley (feeder) or drive pulley (main).
  • Rocks packed at the heel of the arm back from the tip section (arm 3 on a TB-105 or 110, arm 4 on a TB-130).  There is supposed to be a v-scraper there to guard the close clearance between the heel pulley and the steel end frame.
  • Feeder motor hoses kinked.  Active (hydraulic lift) feeder machines (TB130, 80 & 110) can do this if the feeder is slewed more than one time around.  On 105’s, feeder lines can get pinched in the transfer.  Also check 105 feeder line quick connects to make sure they have not backed out.
  • Is more torque required?  This is as much a hydraulic issue as mechanical.  Most Telebelt feeders operate just fine with 130cc motors.  Belts that are heavily loaded, paving for example, might require 160cc motor.

Do you think oil is flowing but there is not much pressure? 

  • Feeder – check for stripped drive pulley collet or broken motor shaft.
  • The Main has 2 motors that plug into splined adapters welded into the ends of the pulley shaft.  If the welds on an adaptor break, that motor will be free to spin.  You will hear oil going through the motor.  Operators have finished pours by capping the lines to the “bad” side motor, thus forcing the other motor to drive the pulley.
  • Check main motors for broken shafts.

Are the belts tight enough? 

  • Feeder belt pulleys are more likely to slip, especially if they are the old-style steel-lagged pulleys.  Maintain feeder tension at 1,500 to 1,800 PSI.
  • Once in a while, you will find a ready-mix driver that will wash what he spills.  If he gets the back side of a loose feeder belt wet, the drive pulley might slip. 
  • Main conveyor pulleys are less likely to slip, even if the belts are real loose.  Worn or missing drive pulley rubber lagging leaves a steel surface that will slip.  Maintain main belt tension at 1,000 to 1,200 PSI.
  • Keep lagging grooves, on main and feeder drives, free of grout buildup.

 

 

Q&A Session- Question 2: I am constantly approached by people selling belt, why should I use Putzmeister belting?

ANSWER:

Putzmeister belts have a long track record and proven history of performance. The material specifications and splice procedures are intended for concrete conveyors and the Telebelt application. These details have evolutionized over many years of trail, research, testing, design, and actual use and application. Other belts made with other materials have been tried and tested over those years, and none of the alternatives have ever measured up in longevity. The splice design and methods have changed many times over the years, and Putzmeister has updated the splice design as recently as a couple of years ago.

We have had long-time loyal customers try “bargain” priced belt and most or all of them have come back to using Putzmeister belting and splicing. We have tried everything from urethane belts to “poly” and “poly-blend” fabric belts. We have experimented with “cold splices” and countless variations of splice prep and have always come back to the vulcanized, step and bias splice presently used because of longevity as related to application.

Those of you that have also tried alternative belts and splice methods may have heard that our pulleys are too small. Our chosen belt and splice design takes in to account the size of the pulleys and the fact that we have an aggressive and effective scraper. The splice design reduces that amount of splice area that is going around a pulley or across the scraper. It is a good “rule of thumb” to remember when talking to a belt salesman that that is exactly what he is, a belt salesman. We are an equipment manufacturer that builds machines that use belts, and therefore have a vested interest in how that belt performs in our machine. Our reputation and that of our product depend on it! Some old time worn clichés may apply when shopping for belting;

  1. If it sounds too good to be true it probably is.
  2. Sometimes you do get what you pay for.
  3. And…..Buyer beware.

We realize that technology does change and our industry is no different. We are alert and open minded to product improvement if and when changing technology offers it. However, until any “better mouse-trap” has a field track record that can compare remotely to the forty years plus of design, testing and field application of our present belting and splice design and methods, we humbly recommend that our customers go with a known commodity when considering replacement belts for their Telebelt.