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  new to PVC PIPE manufacturing help me ?

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Author Topic:   new to PVC PIPE manufacturing help me ?

Posts: 3
Registered: Jun 2004

posted June 04, 2004 09:39 AM     Click Here to See the Profile for Kvs   Click Here to Email Kvs     Edit/Delete Message   Reply w/Quote
would like to know the points to look while buying a new extruder for PVC pipe and difference between single screw barell and twin screw barell ? please help me

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jonathan lapointe

Posts: 1
From:granby quebec Canada
Registered: Jul 2004

posted July 15, 2004 11:30 AM     Click Here to See the Profile for jonathan lapointe   Click Here to Email jonathan lapointe     Edit/Delete Message   Reply w/Quote
well for me i think the price of twin screw extruder is really high and take a lot of maintenance.i work with both single and twin screw extruder and can not see a really big difference between.but every one have is opinion!

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Posts: 74
From:Silver City, NM, USA
Registered: Jun 2001

posted August 02, 2004 10:29 AM     Click Here to See the Profile for 2beeps   Click Here to Email 2beeps     Edit/Delete Message   Reply w/Quote
I'd guess that over 90% of PVC pipe worldwide is produced on counter-rotating twin screw extruders--either conical or parallel.This "battle"(single vs.twin) was fought-and won- back in the late 60's and early 70's. Despite the higher initial cost, a twin screw will more than pay for itself due to several factors:

1) Less overweight to maintain minimum wall thickness (5-6% vs. 8-10% for single screws). This is material GIVEN away, since pipe is sold by the length.Twins deliver a much more even melt flow to the die,since they essentially act as positive displacement gear pumps.

2) Lower power requirement for a given output rate, and generally higher outputs for similar sized extruders.

3) Lower formulation costs--lower shear twins need less stabilizer in their formulations.

4) Lower exit melt temp.--easier sizing.

All the above of course assumes the extrusion is carried out using powdered dryblend PVC compound.

Cheers, Skip

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