INNOVATIVE DEVELOPMENTS IN PVC PRESSURE PIPE SYSTEMS AND UNCONVENTIONAL APPLICATIONS

First Brazilian

PVC Congress. Sao Paulo, June 2005.

Mike Osry

DPI Plastics (Pty) Ltd. South Africa

Objectives• Advantages of PVC which have made it the preferred material for pressure pipes for mains water supply and irrigation in most Countries of the world.

• Innovative developments in PVC pipe technology and unconventional applications which demonstrates the materials:

- Versatility

- Cost effectiveness

- Long-term durability

What is PVC?

• Polyvinyl Chloride – Unplasticised PVC

or PVC-U.

• Polymerisation of Vinyl Chloride

manufactured from oil and salt.

• Only 43% of PVC made from non-renewable

Petroleum feed-stock and 57% from

salt.

• Supplied in powder form to Pipe

Manufacturers.

What is PVC?/Cont.• Mixed in high-speed mixers with stabilisers and other additives.

Dryblend suitable for extrusion into PVC pipes.

• PVC is very versatile and formulations can be made to give special properties:

- High strength PVC-U pressure pipes.

- Impact modified PVC pressure pipes (PVC-M) with greater toughness.

- Sewer and drainage pipes with filler for greater stiffness and cost benefits.

- Products with high resistance to sunlight (e.g. rainwater gutters).

Extrusion of PVC Pressure Pipes

• Twin Screw Extruders designed to provide the right combination of shear and heat.

• Gellation, the melting of the PVC polymer particles through heat (185oC) and shear – the key to the development of PVC’s excellent properties.

Outside diameter and wall thickness is accurately controlled to close tolerances.

Extrusion of PVC Pressure Pipes/Cont.

• Socketed in-line to standard 6m lengths.

• Sealing rings inserted.

• Pipe now ready to use.

PVC-U: Historical Overview

• World’s leading plastic pipe resin – over two-thirds ofglobal demand (by weight).

• Proven durability over approximately 60 years : WHY?

• Continuous Improvements:

- PVC Polymer

- Raw Material Formulations

- Extrusion equipment

- Properties and quality of PVC-U pipes.

- Quality testing and quality management systems (ISO 9001-2000)

Development of Tough PVC Pipes

Motivation:

Harsh environments such as mining and civil construction sites

Trend to larger diameters and pressure classes

Handling and installation

Predictability of long-term performance

Safety in underground mining

Example of a harsh environment!

Impact Modified PVC Pipes in Mining• Extreme conditions of temperature, transport, handling and installation.

• Gold mines now down to 5 000m underground.

• Major requirement is safety.

- Rock face temperature underground : 50oC.

- Ambient temperature >40oC, humidity 90%.

- To cool environment – pipes with chilled water at 5oC.

- Pipes made to SANS 1283.

20 metre high energy impact test

Impact Modified PVC in Mining/Cont.

Impact Test Samples of PVC Mine Pipe Showing Toughness Properties

(20kg mass from 20m height)

Mine pipe Jointing - Minelok

• Pipes are suspended along haulage ways (not burried).

• Therefore pipes require a positive locking joint to resist end thrust.

• ‘Victaulic’ steel flanged joint especially developed for PVC mine pipes.

• Steel Minelok ends pressed onto PVC pipes – interference fit.

• PVC pipes fully compatible with steel pipes used in mines.

Minelok Steel End Coupling

PVC Mine Pipe Coupling System

Installation with Bent Pipes! (2500m)

Mineflo Pipes Conveying Chilled Water (5oC)

Note suspension of pipes underground

Mineflo Pipes for Chilled Water

Chilled Water PVC Pipe Installation in Mine Haulage Way

Backflo Pipes in Mining

• High pressure return of slurries and slimes back underground.

• Work on existing mine dumps to extract gold and return underground.

• Prevents the Johannesburg ‘Mine Dump Skyline’!

Airflo PVC Pipes

• 7 bar compressed air in mines (rock drilling, pipe installation, etc.)

• Pipes must be ‘fail-safe’ under all conditions – stored energy effects.

• High toughness and ductility – high speed detonation tests.

Drainflo PVC Pipes

• Used for draining water back out of mines.

Hi-Impact Pipes – Johannesburg City Council

• These tough pipes used extensively by Johannesburg City.

• Ease of handling and installation vs. steel pipes.

• End-thrust resistant joints reduce need for thrust blocks in installations.

• Made to SANS 1283.

Material and Energy Efficient Pressure Pipes

Motivation:

• Limited capital resources.

• Critical need for potable water in developing countries.

• Reduce poverty and disease.

• Improve quality of life.

Ultraflo PVC-M Pressure Pipes

• Successful history and proven durability with modified PVC pressure pipes in mining environment.

• Toughness as important a property as strength.

• PVC-M pressure pipes made to SANS 966-Part 2.

• Also made in UK, Australia and New Zealand to local standards.

• Pipes in 6m lengths with integral socket and rubber seal.

Ultraflo PVC-M Pressure Pipes/Cont.

• Ease of manufacture, especially in large diameters – up to 630mm or greater.

• Larger pipe bore and increased hydraulic capacity.

• Working pressures of 6, 10, 16, 20 and 25 bar.

• Ease of transport, handling and installation.

• Over 40 000 km installed in Southern Africa over 10 years (one manufacturer).

Biaxially Oriented PVC (PVC-O)

• In-line process with high output rates per meter.

• High strength and toughness.

• Cost effective – higher pressures up to 20 and 25 bar.

• Material efficient product with excellent handling and installation.

• Increased hydraulic capacity.

• Resistance to pressure surges and fatigue caused by pressure cycling.

• Made to SANS 1808-85: 2004.

A construction site illustration of the toughness properties of PVC-O Pipes

Worldwide Use of PVC Pressure Pipes

• PVC Pressure pipes used for almost 60 years.

• Advances in:

- PVC polymer raw material

- Pipe extrusion technology

- Quality management systems and testing procedures

- Pipe Quality

- Pipeline design

- Ease of installation

• All ensure long lifetime and low operation costs.

• Current Life Cycle Assessment now assumes a Lifetime of 100 years.

• In the USA, the use of PVC is more than three times that of HDPE and double that of ductile iron.

• PVC is the world’s leading plastic-pipe material (over 66% of global usage).

Worldwide Use of PVC Pressure Pipes/cont.

THANK YOU FOR YOUR ATTENTION

THE FUTURE IS IN OUR DREAMS