Glycon's SmartBarrel

(patent number 7,409,775)

Eliminate guess-work and stay productive

Processors have always known that wear reduces productivity and causes increased energy consumption. In fact, a worn screw can actually be more detrimental to processing than an improperly designed screw. Until now, there has never been a convenient way to monitor wear without interrupting production and incurring high labor costs.  Consequently, most processors put it off and repair or replace worn components only when their process has deteriorated when it is no longer practical to operate. Now SmartBarrel™ gives processors a way to monitor wear, determine the wear rate, eliminate the guesswork and change out components at a strategic time, before process efficiency declines.

How SmartBarrel Works

The SmartBarrel system is installed when a new processing machine is purchased or when the screw and barrel are being refurbished. Monitoring ports (similar to pressure transducer ports) are drilled in the barrel at one or more locations where liner wear can be anticipated. Then a plug, specially machined from material that is similar to that of the barrel, is installed in the hole. After the new plasticating unit is installed on the machine, baseline measurements are taken before production starts. The plugs are removed from the barrel and a digital-indicating fixture is mounted over the hole to measure the distance through the barrel to the flight surface. Then all the plugs are placed in a fixture that takes a reading of their dimensions.

Once the critical baseline measurements of the screw and barrel plugs are recorded, production can begin. Subsequent measurements can be taken whenever it is convenient: when a heater is being changed, or other maintenance is being performed. The measuring process takes only minutes. Machines running abrasive polymers or fillers can be checked frequently; non-abrasive materials, less frequently. Once three or four readings have been taken and correlated with machine hours, machine cycles or volume of material processed, a “rate of wear” can be determined.

The Glycon SmartBarrel tool kit comes complete with everything a processor needs to organize a program to monitor screw and barrel wear, including digital indicator and fixtures used for taking accurate wear measurements on both the screw and barrel plugs.

Mind the Gap!

How can you tell when screw and barrel wear is causing production standards to decline and profitability to suffer?

The melting and mixing characteristics of the typical plasticating unit are defined by the interaction of the rotating screw and stationary barrel. So as wear inevitably widens the radial clearance “gap” between screw and barrel, the process degrades. Initially, a small amount of wear has very little effect on productivity. Minor adjustments to screw speed and temperature settings are usually all that’s necessary to maintain rates. However, tests show that, at a certain point, the radial clearance gap between the screw and the barrel reaches a critical point where energy costs soar and throughput declines dramatically (Figure 1).

Measuring the wear-induced gap the old-fashioned way- by shutting down, allowing the machine to cool, disassembling the machine and then taking manual measurements- is labor-intensive, time-consuming and costs valuable production time. With SmartBarrel, on the other hand, measurements can be taken in a matter of minutes, even while the machine is near processing temperature, so it is not necessary to endure prolonged shutdown to track wear. By correlating wear measurements with process data (screw speed, melt temperature, power consumption, etc.) the processor can determine when wear begins to have a serious impact on efficiency and profitability (Figure 2).

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