Pipe systems for hydro-power plants

Pipe systems for hydro-power plants “Poliester Grupa” as a company has due to long tradition in processing and utilisation of polyester, particularl...
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Pipe systems for hydro-power plants

“Poliester Grupa” as a company has due to long tradition in processing and utilisation of polyester, particularly production of GRP pipes, and collaboration with world most famous international companies from this area, gained enormous experience and knowledge. Reference list of projects proves this.

01.

Production process Polyester pipe is manufactured of unsaturated polyester resin reinforced with glass fibre with addition of additives and fillers. Usual name for these pipes is GRP pipes or fibreglass pipes. By different combinations of glass fibre, polyester resin and filler, it is possible to acquire a pipe with big span of mechanical and physical-chemical characteristics, a pipe capable to comply with a wide spectrum of operation requirements. Production procedure for manufacturing of these pipes is continuous; it is possible to acquire a pipe of different lengths, and production process uses a combination of choppable and continuous glass fibre which give a high performance qualities to the pipes. Fibreglass composite technology enables polyester pipe to be successfully compared with pipes of traditional materials, concerning longevity – price ratio, which represents a base for performance qualities. Since fibreglass composites provide such an extraordinary combination of properties enabled by ratio price/performances, the number and kind of products manufactured efficiently, effectively and in a good quality of composite materials, increases each year. Composites reinforced by glass fibre have proved it's qualities in a pipelines made in a cold environment of Alaska, under hot sun of Arabic desert, in chemically aggressive environment of Mexico golf and in a beauty of the latest car models. These composites can be accommodated to any of these circumstances, and even more, because a combination of thermo-active resin, glass fibre and suitable process, gives a product far more worth than a pure sum of it's components.

protecting glass fibre foil

roving flow glass fibre saw sand and chopped roving

engine drive

Graphic outline of pipe production process

polymerisation

C glass computer and control display

finished pipe dosage pumps

day containers

02.

Pipe wall structure

Layer

Construction

Purpose

Inner layer

"C" glass

Protection

Border layer

Chopped glass fibre

Protection

Inner structure layer

Continuous glass fibre and chopped glass fibre

High coefficient of structure reinforcements

Core

Silica sand and chopped glass fibre

Durable - hard core

Outer structure layer

Continuous glass fibre and chopped glass fibre

High coefficient of structure reinforcements

Outer layer

"C" glass

Protection

Note: Resin is implied in each layer

Outer layer Outer structure layer

Pipe wall structure Core

Inner structure layer Border layer Inner layer

03.

Advantages of the product: Long and efficient operating life Costly cathode protection is not necessary Costly lining, coating and painting are not necessary Law maintenance costs Hydraulic properties remain unchanged for a long period Withhold properties both in very hot and cold climate Low weight (1/4 of cast iron pipe weight or 1/10 of concrete weight) which facilitates installation on heavy grounds Extraordinary wall sleekness Water hammer pressure approximately 50% lower compared to still and cast iron under the same circumstances Produced in long pipe sections Double muff joints with rubber gaskets are produced of reinforced polyester Pipe specifications comply with world wide standards Production is based on advanced technology Easy to install. Expensive installation equipment is unnecessary. Transportation costs are low. Minimal silt precipitation contributes to very low maintenance cost Lower number of joint points decreases installation time. Easy joining – shorter installation time. Non-permeable and efficient couplings are constructed to eliminate infiltration and leakage. Joining connections are not necessary. Enables flexible changes of pipeline axes. Enables high quality specification of the product. Permanent quality ensured for all purposes. UV Stability provided.

Physical – chemical characteristics Density .................................................................................................................................................................................... (1800-2100) kg/m3 Elasticity module ............................................................................................................................................................................... (6 -24 )GPa Circumferential elasticity module – tensile and bending ................................................... 17 000 MPa – low pressure pipes 24 000 MPa – high pressure pipes Elasticity module longitudinal - tensile and bending ..................................................................................... (6000-12 500) MPa Tensile strength circumferential ............................................................................................................................................ (130-700) MPa Tensile strength axial ..................................................................................................................................................................... (30-60) MPa Bending strength circumferential ........................................................................................................................................... 140-500 MPa Elongation to break ................................................................................................................................................................................ 1,5-2,0 % Linear spreading coefficient ................................................................................................................................................ 24-30·10 -6 1/°K Max. temperature of transported media ............................................................................................................................................. 50 °C Temperature conductibility coefficient ............................................................................................................................ 0,14-0,25 W/mK

Hydraulic characteristics Absolute hoarseness .................................................................................................................................................................. “ k“ = 0,012 mm Hazen Villiams constant .................................................................................................................................................................... “ C“ = 150 Manning constant ............................................................................................................................................................... “ n“ = 0,0095-0,012

04.

Standards Here is review of standards applied for production, testing and quality verification of polyester pipes.

1. STANDARDS FOR CONTROL AND TESTING OF RAW MATERIALS Standards for control and testing of resin quality 1. ISO 2555 - viscosity testing 2. ISO 25353 - gel time testing 3. ISO 2811 - density testing 4. ISO 3251- Styrene content determination 5. ISO 2114 /-Acid number determination 6.ISO 584 / Resin reactivity.

Standards for control and testing of reinforcement fibre 1.ISO 1889- Linear density determination (tex) 2.ISO 3344- Moister content determination 3. ISO 1887 - Loss on ignition 4. ISO 3268- (OC R110) Tensile strength and reduction factor 5.ISO 2078 -Glass type 6. SNO5320- Resin wet out time

Standards for control and testing of silica sand 1.OC R 115/-Carbonate content 2.OC R 114- Moister content 3.OC R 112- Loss on ignition 4.OC R 116- Resin wet out time 5.ASTM E11- Granulation

Standards for control and testing of styrene 1.ASTM D2121 - Polymer content in styrene monomer

Standards for control and testing of methilethilketonperoxide (MEKP) Co octoate 1.ISO 2555 - Viscosity testing 2.ISO 2535 - Ignition time testing 3.OC R111 - water content in MEKP

05.

Standards

2. STANDARDS FOR CONTROL AND TESTING OF PIPES 1.ASTM D3567 2.AWWA C950 3.ASTM D3517 4.ASTM D3754 5.ASTM D3262 6.ASTM D2412 7.ASTM D2583 8.ASTM D 790 9.ASTM D2290 10.ASTM D 638 11.ASTM C 581

Standard procedure for determination of pipe and fitting dimension Standard for high pressure pipes for water supply Standard specification for fibreglass pipes for high pressure Standard specification for fibreglass pipes for sewage and industrial waste water Standard specification for sewage pipes Pipe stiffness and deflection Hardness acc. Barcol Bending properties of plastic materials Circumferential tensile strength Elongation properties of plastic materials Standard procedure for determination of chemical resistance of resin used in structures with reinforcement of glass fibre purposed for transport of liquid 12.ASTM D4161 Standard specification for joints of fibreglass with usage of flexible gaskets of elastomer 13.ASTM D1172 Laminate structure (pipe) 14. ASTM D3839 Standard procedure for underground installation

Production programme Pipe programme Pipe diameters POLIESTER pipes are available in wide spectrum of diameters along with necessary fittings and accessories. POLIESTER pipes can be delivered with following nominal standard diameters DN (mm). Pipe diameters DN (mm) 300

700

1300

1900

350

800

1400

2000

400

900

1500

2100

450

1000

1600

2200

500

1100

1700

2300

600

1200

1800

2400

06.

Pressure classes Pipes are delivered in pressure classes from 1 bar to 32 bar, and it should be underlined that all pipes pressure class over 1 bar are 100% tested on test pressure according to required test standard. Pressure class Designation

Operating pressure

PN

KPa

bar

1

100

1

2,5

250

2,5

6

600

6

10

1000

10

16

1600

16

20

2000

20

25

2500

25

32

3200

32

hydrostatic pressure testing

Stiffness class Pipe stiffness is capability to overtake crown load of ground and traffic, as well as negative inside pressure. POLIESTER pipe are delivered with following tangential initial stiffness (STIS) EI/D3

Stiffness class

stiffness and deflection testing

Designation

Stiffness

SN

Pa

1250

1250

2500

2500

5000

5000

10000

10000

Lengths Standard lengths of polyester pipes are 6 m and 11,8 m. All lengths up to 11,8 m can be delivered.

07.

Fittings and accessories A wide range of GRP fittings and accessories is available along with pipe programme. This includes: bends, branches, flanges, reducers (concentric and non/concentric) e. t .c. Concentric reducers are used for transition from one to another nominal diameter, and are used primary on pressure pipes. High flexibility of material enables manufacturing of individual fittings based on measures on customers requirement.

"T" branch

Bend 1°-90°

Sloping branch

08.

Flange

Reducer

Specificity of products POLIESTER GRP pipe systems enable solutions for applications characterised by high requirements in regard to huge strength of glass fibres and high level of corrosion resistance of resin. Such combination of mechanical and chemical properties make them ideal for small hydro-power plants.

Characteristics of POLIESTER pipe systems in regard to certain features Flow velocity/ hydraulic properties

++

Corrosion resistance

++

Ratio kg/m

++

UV resistance

+

Heat expansion

+

Chemical resistance

+

Thermal insulation

+

Operation life

++

All production processes are certified by third side and company is certified with certificates like ISO:9001 and other. Pipe systems comply with standards of different countries like ASTM, EN, DIN, BSI, ISO, AWWA and many other international and local standards and certificates.

09.

Nominal project testing pressure Very important qualification test of POLIESTER pipe for application on small hydro-power plants is inner pressure of pipeline. Pressure class must be higher or equal to projected working pressure. It is based on pressure value which the pipe is to withstand at the age of 50 years, and is calculated according to equation:

Pressure tension

PN = HDB(50 years) / FS

HDS

Security factor =1.8

PN

Time

50 years

PN – pressure class HDB (50 years) pressure value which the 50 years old pipe will withstands FS – Security factor, taken FS = 1,8 for operating time of 50 years

Simple transportation 10.

Lay ing o f the p ipe

Pressure declination Elevation loss or pressure decline occurs in all pipe systems, because of level changes, shafts, turbulence caused by direction changes and friction inside pipes and fittings. There are many mathematical methods to determine elevation loss in fibreglass pipes. Most often used methods are those by Hazen-Williams, Manning, Darcy-Weisbach. Acceptability of each of them depends on assumptions. All these methods are applied to fibreglass pipes and they imply comparatively smooth internal surface of a pipe. As indicated in the table of hydraulic characteristics, one may say that absolute harshness is 0,012 mm, Hazen/ Williams constant "C"=150, Manning constant "n"=0,0095/0,012, coefficient of linear expansion (24-30) x10 1/°C. It can also be specified that relation between "hoop" load on circumference and axial reaction is around 0,25, while for the opposite case Poisson's coefficient is a bit smaller. Those who deal with pipe installation know for a great while ago that fibreglass pipes have considerably lower friction coefficient than the pipes of carbon steel. It is very important to get to see the importance of lower friction factor in terms of energy saving and price reduction during working life of a system. Greatest savings come from reductions on pumping costs of a system. Energy consumption often falls to a half. POLIESTER fibreglass pipes do not exhibit any corrosion (they do not change with time), compared to other materials which are corrosive, where corrosion directly affects harshness of those pipes. In these pipe lines, it is possible to use velocities up to 4 m/s when the water is clean and do not contain any abrasive material.

11.

Hydraulic shock (water hammer) Inner shock or pressure surge, generally known as hydraulic shock, occurs as a result of abrupt change of fluid velocity within a system. Passing pressure is a wave which is moving very fast increasing and decreasing pressure in the systems, depending on origin of flow and direction of wave movement. Sudden closure of the valve can cause the shock wave, by transferring kinetic energy of moving fluid into potential energy which has to be distributed. Sudden outlet of the air and setting on and off the pumps can cause shock wave. The size of hydraulic shock is a function of fluid properties and velocity, elasticity module of pipe material, length of the line and change of velocity in fluid quantity movement. Accordingly high compliance (low elasticity module) in fibreglass pipes contributes the effect of self-suppressing as pressure wave moves along pipe system. In fibreglass pipes hydraulic shock is approximately 50% of that in for steel pipe systems under similar conditions. POLIESTER fibreglass pipes according to standard applied, allow pressure waves up to 40% of nominal pressure.

UV stability of the pipe All pipelines of fibreglass are subjected to changes when exposed to sun light. This is superficial phenomena caused by degradation of resin due to ultraviolet radiation. Appearance change rate depends on intensity of sun light and the exposure time. If the resin is heavily degraded on surface, quality is spoiled, glass fibres become visible. They prevent further degradation by absorbing ultraviolet radiation with no damage. Superficial degradation (deterioration of surface quality) has very small influence on operational properties of pipeline system. Prevention or control over atmospheric influence on surface can be attained by painting with paint of quality solvent. Paint adhesion is enhanced if painting is done after a period of exposing to atmospheric influence. In previous long lasting and wide experience in areas of Alaska, under intensive sunshine of Arabic desert, in chemically aggressive environment of Mexican golf, there was no evidence of a structure influence on ultraviolet radiation on long operating life of POLIESTER fibreglass pipes.

Laying of pipes

12.

Pipe installation Installation of POLIESTER pipes can be done in two ways: In trenches – by burring. In underground installation, outside load of material above the buried fibreglass pipe , along with all movable loads, like traffic f. ex. , will induce deflection on circumference of the pipe, which must not be higher than projected. Pipe and material around (soil) accomplish a certain structural system, where both are important for system functioning. As a result, deformation and tension in buried fibreglass pipes strongly depend on, on pipe properties as well as on soil properties. Above ground installation: a) - installation (laying) of fibreglass pipeline directly on field surface b) - fixing (laying) of fibreglass pipeline above the field surface. Requirements for installation of pipeline are basically the same, f. ex. deflection, thermal expansion. Designing a pipeline according to latest technical standards represent a half way to long-lasting and functional pipe system. In order to attain the best result, it is necessary to approach installation very carefully taking care of all details. Final choice of installation type depends on different parameters. For underground installation, It is obligatorily recommended to perform geological -technical soil research , and for slopes steeper than 150 verification based on founded geological-technical research is needed, taking in consideration that stability of supports is directly connected with ground properties.

Above ground pipe installation on steep slopes has many advantages: Easy control of installation quality Changes on the ground (settlement, sliding) are easy to detect, and a problem can be solved fast. Calculation of support type is easier than assessment of soil structure. The load on pipe system is lower, and this is important for pipe anchoring. Any problem on pipe system can be easily solved.

Joint systems for fibreglass pipes There are many systems and variations in those, which satisfy requirements of national standards, and are available for fibreglass pipe products. Many systems comply with requirements of specific projects. Main categories in jointing polyester pipes: Polyester coupling Metal coupling Butt and strap (frontal) connecting joint Flange

13.

POLIESTER coupling Polyester coupling is symmetrical bilateral sliding joint of polyester reinforced with glass fibre. It is delivered with rubber sealing rings and rubber profile - stopper in the middle of coupling. Sealing rings (provide tightness) and stopper (ensures correct position of pipe and sleeve) are placed in chamfers of a coupling, which are precisely mechanically treated. Three parameters contribute efficient sealing with polyester coupling: • Sealing with flippers • Gasket compression • Wedge shaped chamfers Polyester pipe couplings non restrained, guard inner pressure, but not an axial force which can be guarded by restrained pipe couplings. Couplings can be delivered installed on one end of the pipe, or separately if requested.

stopper coupling body

gasket

Graphic outline of joint with polyester coupling

POLIESTER coupling elements pipe beginning pipe end

gasket stopper coupling body

Polyester coupling

Metal coupling Metal coupling - Straub, Teekay and other, are used for pipe joining, as well as for repair operations on pipeline. It may be with opening possibility or fixed. It consists of still mantle with inside rubber sliding gasket. The mantle can be made of stainless steel or coated with special paint.

Metal coupling fixed

Metal coupling with hinge

14.

Butt and strap joint Butt and strap joint is used for joints which need to withhold axial tensions of closure (for pipelines laid under water surface). Joint is made of glass fibre and polyester resin. Joint length and thickness depend on pipe diameter and working pressure. It is mainly used directly in site. This type of joint also guarantees safe and long-lasting type of connection which takes axial loads.

Butt and strap joint

Flanged joint Flanged joint - offers as well reliable jointing and possibility of disassembling in some further phase if necessary. This joining is suitable also for connecting with pipes of other material, as well as valves and various other accessories. Two types of junction with flanges are delivered: • Previously moulded stable flanges on parts of polyester pipe. • Previously moulded movable polyester flanges and muff on polyester pipe.

Joint with stable flanges

15.

Joint with movable flanges

Consulting assistance Our technical support is at your disposal in all areas regarding POLIESTER pipe system: •Assistance in design and selection of most suitable materials considering pressure, stiffness, temperature and corrosion. •Assistance in selecting configuration of pipe installation with all elements. •Assistance with hydraulic pressure calculations. •Assistance with stress calculations for pipeline. •Assistance in form of supervising of construction works.

Reference list Of many projects of small hydro-power plants (SHP), abstracted are some with base characteristics indicated in table below.

Ref. nr.

Buyer - Country

Name

DN (mm)

Stiffness (Pa)

Pressure (bar)

Length (m)

1.

MHE „ERS“ Laktaši, BH

Sućeska I

DN 800 -900

SN 5000

PN 6 -25

4100

2.

MHE „Gorno Belički izvori“ Skopje, Macedonia

Belica I Belica II

DN 600-700

SN 1250 -2500

PN 1 -25

10000

3.

„Eling Inženjering“ d.o.o. Banja Luka, BH

2 power plants

DN 1500 1800

SN 1250 -2500

PN 1 -6

2400

4.

MHE „Ezero“ Skopje, Macedonia

Ohrid I Ohrid II Ohrid III

DN 300-600

SN 1250 -2500

PN 1 -32

3400

5.

„ Rose Wood“ Gornji Vakuf, BiH

3 power plants

DN 4001000

SN 5000

PN 6 -32

6000

6.

„ Paloč“ d.o.o. Gornji Vakuf, BiH

3 power plants

DN 600-800

SN 5000 - 10000

PN 6 -32

7100

7.

MHE „Zagradačka“d.o.o. Prozor, BiH

Zagradačka

DN 500-600

SN 5000

PN 10 -25

1400

8.

Elektro grupa „Jajce” Jajce, BiH

Voljevac

DN 1500 1700

SN 5000

PN 6

1400

9.

„ Vesna S“ d.o.o. Bugojno, BiH

1 power plant

DN 500-700

SN 5000

PN 6 -16

1100

10.

„ Tehel“ d.o.o. Sarajevo, BiH

1 power plant

DN 700

SN 5000

PN 20

500

11.

Vlašić“„ d.o.o. Travnik, BiH

1 power plant

DN 500

SN 5000

PN 10 - 20

1600

12.

„ ECO ENERGY“ d.o.o.Tuzla, BiH

Osanica 4

DN 700

SN 5000

PN 6 - 16

300

13

ADRIJA PRODUKT d.o.o. ZENICA - BiH

Bistričak

DN900-1000

SN 5000

PN6 -10

2100

14

ELKATA - Romania

Elkata

DN350 -1100

SN5000

PN6 -16

5800

15

HIDRO KOP BANJA LUKA- BiH

Paklenica

DN400-500

SN10000

PN10 -16

4000

16

ING EKO PROZOR RAMA -BIH

Duščica

DN1200

N5000

PN6

920

17

MHE „ERS“ Laktaši, BiH

Sućeska II

DN 600-500

SN 5000

PN 6 -30

4100

18

MPP Jedinstvo Sevojno - Serbia

Džep

DN 7001000

SN 5000

PN 10

2700

Note

16.

17.

2400

2300

2200

2100

2000

1900

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

800

700

600

500

450

400

350

300

DN (mm) PN (bar)

SN (Pa) 1

2,5

6 10 16 20 25 32

2500 1

2,5

6 10 16 20 25 32

5000 1

2,5

6 10 16 20 25 32

10 000

Following table shows production programme of GRP POLIESTER pipes

Poliester Grupa d.o.o. Priboj ul. Pribojske čete br. 44 31330 Priboj Srbija

All data and recommendations found in this brochure are given with great care and accuracy. However manufacturer does not accept responsibility for any kind of problems, which may arise as a result of possible errors in this brochure, and in particular with no previous mutual consultations.

18.