Page 33 - Plastics News October 2019

FEATURES

6WHSV WR 0RUH (I¿FLHQW &HQWUDO 3QHXPDWLF &RQYH\LQJ

Joseph Dziedzi
Depending on when you bought and installed it, there are ways to tweak your central pneumatic conveying
system to improve its performance and save you some money.

n our economy today, as energy costs rise and the cost of the box or the gaylord, the material source has run out
Iof manufacturing increases, it is becoming more of RI PDWHULDO RU WKH EDJ OLQHU KDV REVWUXFWHG WKH ÁRZ RI
a challenge to stay competitive in regional and global material. Be sure that the supply of material is constantly
environments. Manufacturers are constantly looking ÁRZLQJ LQWR WKH SLFN XS SRLQW
for ways to improve their processes and boost their The perfect vacuum or pressure piping system consists
competitiveness. Plastics processors who have central of one straight length of piping with no bolted couplers,
pneumatic material-handling systems are already QR GLYHUWHU SRLQWV QR HOERZV DQG QR ÁH[ KRVH 7KLV LV
EHQHÀWLQJ IURP ORZHU SULFHV RI EXON UHVLQ SXUFKDVHV an example of a system with minimal obstacles and
compared with lower-volume purchases. Depending on minimal pressure drop, assuming it is properly sized for
when the centralized conveying system was installed, the system. But it’s not realistic. In the real world, piping
there may be ways to make incremental improvements must always be routed up or down and around in a plant
WR HQKDQFH SHUIRUPDQFH HIÀFLHQF\ DQG XOWLPDWHO\ DGG to avoid obstacles to get the material from the source
savings to the bottom line.
to the destination or use point.
Piping should always be installed with the minimum
number of elbows and should use the shortest amount
RI ÁH[LEOH KRVH 5HGXFH H[FHVVLYH DPRXQWV RI ÁH[ KRVH
at quick-coupling stations. Reduce long loops of coiled
ÁH[LEOH KRVH DQG SDUH WKH DPRXQW RI ÁH[LEOH KRVH WKDW
connects the hard piping to the quick-change stations
and/or material probes. These are quick and easy ways
to gain conveying capacity by eliminating pressure losses
It is easiest to start at the beginning of the line and follow within the conveying system.
the pellet, powder or granulate on its journey from the
source or the pick-up point. It is good practice to adjust Elbows that are installed back to back can cause material
your conveying system at the pick-up point, with your WR GURS RXW RI WKH DLU VWUHDP $GG D VXIÀFLHQW OHQJWK RI
wand or take-off tube, so that it will provide a good straight pipe between them. This will allow the material
mixture of air and material. This will allow the material to pick up in the air stream and gain velocity, improving
WR ÁRZ VPRRWKO\ WKURXJKRXW WKH V\VWHP ZLWKRXW VOXJJLQJ WKH RYHUDOO V\VWHP HIÀFLHQF\
Using the right type of pick-up device can enhance Air leaks in piping will reduce the system capacity and,
\RXU V\VWHP SHUIRUPDQFH DQG LPSURYH HIÀFLHQF\ )RU in some cases, can lead to material slugging or lines
long-distance conveying, it is typical to use a dual-tube plugging. Check for loose bolted couplers between piping
take-off compartment, which draws material from the connections and worn or missing gaskets. Fix or replace
EDFN RI WKH ER[ 7KLV PDNHV LW HDVLHU IRU WKH DLU ÁRZ WR them and tighten all couplers. Replace worn-out piping
entrain the material as it travels through the pipe to and elbows. Set up a regular inspection schedule for
its destination at the process machine. Finding a good system piping. Running a system with air leaks and worn
mixture of air to material is critical to proper conveying. piping will reduce the potential rate of the system. In
extreme cases, there will be plugged lines and multiple
One of the most common issues in a conveying system, maintenance issues with the system.
DQG RQH WKDW FDQ HDVLO\ HQKDQFH DQG LPSURYH HIÀFLHQF\
LV WR NHHS PDWHULDO ÁRZLQJ LQWR WKH SURFHVV $ VLPSOH UXOH 5HGXFLQJ H[FHVV SLSLQJ HOERZV DQG ÁH[ KRVH LQ D V\VWHP
WR IROORZ LV ´3XW WKH ZDQG LQ WKH ER[ µ 0DQ\ WLPHV D ZLOO LPSURYH FRQYH\LQJ V\VWHP HIÀFLHQF\ DQG UHGXFH WKH
system issue is caused by lack of material supply. This overall energy required to run it. Eliminating air leaks
typically occurs when the material probe has fallen out will allow the energy put into the system to be used for

33 October 2019 Plastics News