GLASS REINFORCED PLASTIC
PIPES
CONTINUOUS
MANUFACTURING LINE
Technical
report
Index
1 GENERAL
ON CONTINUOUS GLASS REINFORCED POLYESTER PIPE PRODUCTION
2 G.R.P.
PRODUCT CHARACTERISTICS
2.1 GRP
Pipes Wall Description
2.2 End
Couplings
2.3 Fittings
2.4 Advantages
in G.R.P. Application
2.5 Inspection
and testing
3 RAW
MATERIALS
3.1 Resins
3.2 Glass
Reinforcements
3.3 Auxiliary
Raw Materials
4 FACTORY
DESCRIPTION
4.1 Production
Capacity
4.2 Factory
Layout And Installations
4.2.1 Total Extension
4.2.2
4.2.3 Sand Store and Feeding System
4.2.4 "E" And "C" Glass Fiber Distribution System
4.2.5 Resin feeding and mixing system
4.2.6 Utilities and Ancillary Installations
4.2.7 Electric Installations
4.2.8 Service Buildings
4.2.9 Open Spaces
5 PIPE
MANUFACTURING PROCESS DESCRIPTION
5.1 Continuous
Pipe Technological Process Description
5.2 Manufacturing
production rate (mt/hr.)
6 PRODUCTION
EQUIPMENT
6.1 Continuous
F.W. Machine
6.1.1 Mandrel
6.1.2 Resin dosing station.
6.1.3 Polymerization Oven
6.1.4 Process Parameters Control Device
6.1.5 Computer Control of F.W. Machine
6.1.6 Gauging, chamfering and cutting device
6.1.7 Dust and Styrene suction system
6.1.8 Pipe lifting and supporting planes
6.1.9 Pipe antitorque supporting equipment
6.2 Sleeve Coupling Manufacturing Machine
6.3 GRP
pipe sleeve joint joining equipment
6.4 Maintenance
7 PERSONNEL
REQUIREMENT
7.1 General
7.2 Process
Equipment Personnel
7.3 Fitting
Manufacturing, Prefabrication, Testing and Handling
7.4 Total
Manpower
8 TRAINING
OF LOCAL PERSONNEL
8.1 Location
Of Courses
8.2 Personnel
To Be Trained And Course Duration
8.3 Preliminary
Design
8.4 Know
How And Engineering
8.4.1 Basic Design
9 TECHNICAL
SERVICES AND PLANT COMMISSIONING
9.1 Plant
Erection Supervision
9.2 Start
Up, Commissioning and Training
9.3 Acceptance
Test Procedure
9.3.1 Purpose
9.3.2 Content and method
9.4 General
Assistance
9.5 Running
Assistance
9.6 Training
on Site
10 EXCLUSIONS
FROM THE SUPPLY
11 ACTIVITIES
The present proposal covers the
implementation of a new factory for the manufacture of glass reinforced plastic
(G.R.P.) pipes through the establishment of :
-
Continuous line for the continuous production of pipes with
diameters from 300 to 2600
The project covers the
installation of the production facilities relevant to the manufacture of pipes
with diameters ranging from 300 up to
The G.R.P. pipe wall consists of three
layers perfectly adherent with one another, each having different
characteristics and properties in relation to their function. The properties of
chemical resistance and impermeability are, anyway, equivalent for the three
layers which are namely:
§
liner:
It is in direct contact with the conveyed
fluid and guarantees the maximum resistance to the chemical attack from the
fluid itself. Moreover, the liner presents an internal surface particularly
smooth, without defects, cracks or delaminated zones. The liner is composed of
one glass veil and one glass mat tape resin impregnated and is produced in two steps
(inner liner and outer one)
§
filament or mechanical
resistant layer:
Its function is to render the pipe wall
resistant to the stresses due to the design conditions (stresses due to the
internal and/or external pressure, flexural strength due to the external loads
etc.) and generated by transport and laying operations. The thickness of the
filament depend, then, upon the design conditions. The mechanical layer is
composed of winded glass filament roving chopped glass, sand aggregate, glass
mat reinforcement, all polyester resin impregnated.
§
gel coat or external
layer:
It has a thickness of about
The pipe coupling is made by a GRP sleeve
with continuous elastomeric gaskets with double or triple lips.
A wide range of fittings and special pieces
can be manufactured in G.R.P. They present, therefore, the same
characteristics, both chemical and mechanical, of the pipes. Fittings are
manufactured manually employing male moulds or pipes pieces to be joined
together. Ends of fittings can be bell and spigot type provided with sealing
gaskets or plain type to be joined by welding to adjacent pipes or other
fittings. The normal production of the new factory includes:
-
90° or 45° bends (by
moulds)
-
concentric and eccentric
reducers (by moulds)
-
fixed flanges and stub end
(by moulds)
-
blind flanges (by moulds)
Moreover, other special pieces such as
manholes, flanged pipes equal and reduced tees etc. can be manufactured by
welding together fittings and/or pipes sections.
Glass reinforced plastic pipes represent
the ideal solution for the adduction of any kind of water, chemicals, effluent
and sewers, because they combine the advantage of corrosion resistance, typical
of plastics, with a mechanical strength which can be compared with the steel
one. Typical properties that result in advantages in G.R.P. pipes application
can be summarized as follows:
-
Low weight of pipes
lengths that allows for the use of light laying and transport means.
-
Possibility of nesting of
different diameters of pipe thus allowing additional saving in transport
operations.
-
Length of sections larger
than other materials ones.
-
Easy installation
procedures due to the kind of mechanical bell and spigot joint.
-
Corrosion resistance, both
of the external wall in contact with the conveyed fluid. No protections such as
coating, painting or cathodic are then necessary.
-
Smoothness of the internal
wall that minimizes the head losses and avoids the formation of deposits.
-
High mechanical resistance
due to the glass reinforcement.
-
Absolute impermeability of
pipes and joints both from external to internal and vice-versa.
-
Very long life of the material
virtually infinite, which does not need maintaining.
-
Workability of the
material in site employing simple equipment.
Before starting up production a check is
made on the quality and characteristics of the resins relatively to the
temperature and relative humidity in the production shops.
Optimum values of viscosity and temperature
to be applied to the resin are pre-established, and the percentage of catalyst
to be employed in the production phase is determined.
Controls in the production shops:
-
control of lay-up (unit
weight per square meter of resin and glass, type of resin and type of
reinforcement)
-
internal quality control
-
check on the type of glass
reinforcement used
-
dimensional control of the
positioning of the accessories according to technical specifications
-
check on thickness
-
Check on
post-polymerization treatment (on continuous pipes). Continuous pipes
manufactured are put into an oven having forced circulation of hot air and
undergo heat treatment there. The purpose of this treatment is to complete the
cross-linking of the resinous matrix. The degree of polymerization is directly
related to the percentage of residual styrene monomer, which is established by
laboratory analysis.
-
Chemical tests: The
quantity of styrol in the solution is deduced by comparing its peak with the
peak of precisely known quantity toluene. A maximum of naught point two percent
of free monomer is accepted (naught point five percent is permissible by law).
-
Checking the weights: As
it is withdrawn from the post-polymerization oven the product is weighed to
ascertain the difference between the real weight and the weight foreseen in the
theoretical construction sheets.
-
Checking the Barcol
hardness: Measurement of the hardness gives an indication of the degree of
polymerization. This test is carried out on fifty percent of the products made.
The raw materials employed for the
manufacturing of pipes are mainly polyester resins and glass reinforcements in
the form of veils, chopped strands, woven roving and continuous filaments.
The polyester resins belong to the group of
alkyd resins and present themselves in the form of colorless or slightly amber
viscous liquids. In the commercially available state, the resin composition is
represented by long linear chain, obtained by esterification of dicarboxyl
acids with glycols and then dissolved in one or more saturated liquids
monomers. One of the basic characteristics of polyester resin, is the presence
of unsaturated bonds arising from the use of maleic anydride or other
unsaturated components during the esterification. During pipes or tanks
manufacturing, the resin hardens due to the polymerization reactions between
the unsaturated radicals contained in the polyester chain. The resin then becomes
a cross linked structure and assumes all the characteristics of thermosetting
products such as, for example, the condensate of phenol, melamine or urea with
formaldehyde. Polymerization reactions and hardening of resins, is promoted by
special catalyst systems which are able to act even without the presence of
high temperatures or pressure. The pipes and tanks production is in fact
carried out at ambient temperature and atmospheric pressure. The mentioned
cross linked bond can be represented by the following scheme:
A.B.A.B.A.B.A.B.
. .
C C
. .
A.B.A.B.A.B.A.B.
.
C
.
A.B.A.B.A.B.A.B.
where:
A represents a polyoxydryl alcohol .
B represents an unsaturated acid
C represents an unsaturated product such as
styrol
By varying the nature of the components of
the resin (that is, by using glycols of different types and acids with a higher
or lower weight) it is possible to obtain resins having different mechanical,
thermal or chemical properties. The most employed resin in pipes manufacturing
are the following:
·
Polyester resins based on
bisphenol or bisphenol A in a solution of styrol monomer.
Viscosity = 3.5 - 4 poises.
Reactivity = medium.
This type of resin provides good chemical
inertness coupled to high mechanical strength in the laminate.
·
Polyester resins based on
isopthalic acid in a solution of styrol monomer.
Viscosity = 4 - 5 poises.
reactivity = medium to high.
This kind of resin assures good mechanical
strength to the laminate and is the best solution, both under the point of view
of economics, reliability and resistance for manufacturing goods to be used to
transport any kind of water.
·
Vinylester resins in a
solution of styrol monomer.
This resin is employed when hot high
corrosive products have to be handled and conveyed.
All the employed resins are, in any case,
thermosetting type that means that the shape of the products, assumed after the
polymerization, is not affected by heating and then high stability at
temperature is assured. The same or different resins, if compatible, can be
employed to manufacture the various layers of pipes.
Glass fibers are produced in the form of
continuous filament, as per the following briefly described process. Various
components are mixed together in order to obtain a basic compound characterized
by a definite composition. The compound is then sent to a furnace, where is
melted at high temperature so as to produce glass. The molten glass is then
drawn into precision size controlled thin filaments. Filaments are successively
processed into roving, mat, yarn or cut strands that are the basic
reinforcements for the thermosetting resins. Glass necessary to produce pipes
are the following:
·
"C" glass tape.
It is in the form of veil with continuously
and uniformly distributed fibers over the whole surface and with a porosity and
stiffness such as to enable handling in the cutting and applying operations.
The veil is packed in rolls and presents
itself as a tape
The main characteristic of the veil is the
high chemical resistance and is, in fact, employed to manufacture the first
layer of the liner of pipes (inner liner).
·
"E" glass
chopped strand mat tapes.
It consists of chopped glass fibers not
woven. The chopped fibers are distributed without any preferential orientation
but in order to assure a regular specific weight to the tape.
The fibers are bonded together with a
polyester base binder. The mat tapes packed in rolls, present a width of
·
"E" glass
filament roving.
It consists of strand of continuous glass
filament roving supplied in rolls. More parallel strands are employed to
manufacture the mechanical resistant layer of pipes. Density or size of roving
is defined in grams per kilometer of single filament (
Filaments are sized with a special sylan
finish that imparts a taping effect to improve the efficiency in winding
operations.
·
"E" glass woven
roving tapes.
It is a tissue made of strands of
continuous filament roving oriented in the two main directions.
They are treated with binders in order to
impart excellent adaptability to the shape of the moulds without any wrinkling,
empty spaces or irregular dripping of the resin to be applied.
The woven roving tapes are employed to
manufacture the mechanical resistant layers of hand made fittings.
The auxiliary raw materials are necessary,
in limited quantities, to promote or inhibit the polymerization reactions in
order to better control and select the working phases both for pipes.
Ultraviolet rays inhibitor agents are employed to increase the already great
resistance to weathering.
The main auxiliary raw materials are
namely:
·
Catalyst for polyester
resins: 50% solution of methyl ethyl ketone peroxide in dimethylphtalate.
·
Accelerator : solution of
cobalt naphtenate in styrene.
·
Inhibitor : 10% solution
of ter-butyl-catechol in styrene.
·
Thixotropic agent :
micronized silica gel.
·
Solution of paraffin in
styrene.
·
Polyvinyl alcohol.
·
U. V. rays inhibitor.
·
Silica sand
Range of producible pipes and factory
capacity, are sized in order to satisfy the local needs of potable water lines
and networks, irrigation and sewer systems.
The proposed factory
is sized for an average manufacturing capacity of 12000 ton/year of finished fiberglass
pipes with average diameters of 300 -
2600 mm, dia.
The factory should cover a rectangular
shape plane area of about
The manufacturing unit consists of steel or
reinforced concrete structure shed of rectangular shape plan and is divided
into a process area and service zones.
The shed of the process area is sustained
by two rows of columns providing
The floor is made of leveled concrete
The shed covers the following
installations:
-
Process area for pipes:
Process area for pipes
including bell coupling
One
overhead traveling crane (5 tons capacity)
Fittings manufacturing
area
-
Services areas:
Resin mixing room
Glass storage area
Warehouse (shelves, welding and drilling
machine, grinders and tools, spare parts).
Quality control laboratory
Dressing rooms, showers and toilets
Pressure test equipment for pipes