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Pipes and bends

(Mechanical Engineers society)

Lahore Pakistan. Created by: Irfan Yousaf From: University of Lahore

TOPICSTOPICS History of pipesHistory of pipes Materials used in pipesMaterials used in pipes Types of pipesTypes of pipes Design considerationsDesign considerations Bending of pipesBending of pipes Forces acting on bendsForces acting on bends Head loss in bendsHead loss in bends Wear resistance bendsWear resistance bends Applications Applications

HISTORYHISTORY The first use of pipe was by ancient agriculturalists The first use of pipe was by ancient agriculturalists

who diverted water from streams and rivers into who diverted water from streams and rivers into their fields. Archeological evidence suggests that their fields. Archeological evidence suggests that the Chinese used reed pipe for transporting water the Chinese used reed pipe for transporting water to desired locations as early as 2000 B.C.to desired locations as early as 2000 B.C.

During the first century A.D. , the first lead pipes During the first century A.D. , the first lead pipes were constructed in Europe. In tropical countries, were constructed in Europe. In tropical countries, bamboo tubes were used to transport water.bamboo tubes were used to transport water.

Colonial Americans used wood for a similar Colonial Americans used wood for a similar purpose. In 1652, the first waterworks was purpose. In 1652, the first waterworks was made in Boston using hollow logs.made in Boston using hollow logs.

Development of the modern day welded steel Development of the modern day welded steel pipe can be traced back to the early 1800s. In pipe can be traced back to the early 1800s. In 1815, William Murdock invented a coal 1815, William Murdock invented a coal burning lamp systemburning lamp system

An early notable method for producing metal tubes quickly An early notable method for producing metal tubes quickly and inexpensively was patented by James Russell in 1824. In and inexpensively was patented by James Russell in 1824. In his method, tubes were created by joining together opposite his method, tubes were created by joining together opposite edges of a flat iron strip.edges of a flat iron strip.

Russell's method was not used long because in the next year, Russell's method was not used long because in the next year, Comelius Whitehouse developed a better method for making Comelius Whitehouse developed a better method for making metal tubes.metal tubes.

This process, called the butt-weld process is the basis for our This process, called the butt-weld process is the basis for our current pipe-making procedures.current pipe-making procedures.

DEFINITION OF PIPE DEFINITION OF PIPE

A A pipepipe is a tubular section or hollow cylinder, is a tubular section or hollow cylinder, usually but not necessarily of circular cross-usually but not necessarily of circular cross-section, used mainly to convey substances section, used mainly to convey substances which can flow — liquids and gases (fluids)..which can flow — liquids and gases (fluids)..

MATERIALS USED FOR PIPESMATERIALS USED FOR PIPES

Pipe are made in many materials including Pipe are made in many materials including ceramic, fiberglass, many metals, concrete ceramic, fiberglass, many metals, concrete and plastic.and plastic.

In the past wood and lead were commonly In the past wood and lead were commonly used.used.

Metallic pipes are commonly made from steel Metallic pipes are commonly made from steel or ironor iron

a.a. carbon steelcarbon steel

b.b. stainless steel stainless steel

c.c. galvanized steelgalvanized steel

Aluminum pipe or tubing may be utilized Aluminum pipe or tubing may be utilized where iron is incompatible with the service where iron is incompatible with the service fluid or where weight is a concern.fluid or where weight is a concern.

Copper tubing is popular for domestic Copper tubing is popular for domestic water (potable) plumbing systems.water (potable) plumbing systems.

Copper used where heat transfer is Copper used where heat transfer is desirable (i.e. radiators or heat desirable (i.e. radiators or heat exchangers).exchangers).

Plastic materials polyvinyl chloride (PVC).Plastic materials polyvinyl chloride (PVC).

chlorinated polyvinyl chloride (CPVC).chlorinated polyvinyl chloride (CPVC).

fibre reinforced plastic (FRP).fibre reinforced plastic (FRP).

polypropylene (PP).polypropylene (PP).

PIPEPIPE

A hollow cylinder or tube used to A hollow cylinder or tube used to conduct a liquid, gas, or finely conduct a liquid, gas, or finely divided solid.divided solid.

TYPES TYPES

1- SEAMLESS PIPES1- SEAMLESS PIPES

2- ERW ( ELECTRICAL RESISTANT WELDED)2- ERW ( ELECTRICAL RESISTANT WELDED)

3-CDW (COLD DRAWN ELECTRICALLY WELDED)3-CDW (COLD DRAWN ELECTRICALLY WELDED)

TYPES OF PLASTIC PIPESTYPES OF PLASTIC PIPES1- PVC ( POLY VINYL CHLORIDE) 1- PVC ( POLY VINYL CHLORIDE)

2- PPRC ( POLY PROPYLENE CHLORIDE )2- PPRC ( POLY PROPYLENE CHLORIDE )

SEAMLESS PIPESSEAMLESS PIPES

Seamless (SMLS) Steel Pipe is made from a solid round steel ‘billet’ which is heated and pushed or pulled over a form until the steel is shaped into a hollow tube. The seamless pipe is then finished to dimensional and wall thickness specifications in sizes from 1/8 inch to 26 inch OD.

ERW PIPESERW PIPES

ERW (Electrical Resistant Welded) pipe cold formed from a ribbon of steel pulled through a series of rollers and formed into a tube which is fused through a electric charge.Common sizes for ERW Steel Pipe range from 2 3/8 inch OD to 24 inch OD in a variety of lengths to over 100 feet. Surface finishes are available in bare and coated formats.

THE ELECTRICAL WELDING IS APPLICABLE FOR LESS THICKNESS OF PIPES

CDW PIPESCDW PIPES

CDW (Cold Drawn electrically Welded) pipes are formed by passing a metal sheet through rollers to giving the circular shape and then welded.

PVC PIPESPVC PIPES

PPRC PIPES PPRC PIPES

PIPE DESIGN & MANUFACTURINGPIPE DESIGN & MANUFACTURING SKETCHSKETCH DRAWDRAW GIVING DIMENSIONS GIVING DIMENSIONS STRESS ANALYSISSTRESS ANALYSIS MANUFACTUREDMANUFACTURED

THICKNESS CALCULATIONSTHICKNESS CALCULATIONS

                     internal pressure

                  working pressure

                  maximum surge pressure

CALCULATION OF FRICTION LOSSESCALCULATION OF FRICTION LOSSES

For laminar flow (For laminar flow (RR < 2000 in pipes), < 2000 in pipes), ff can can be deduced analyticallybe deduced analytically

f = 64/R

For turbulent flow (For turbulent flow (RR > 2000 in pipes), > 2000 in pipes), ff is is

determined asdetermined as

The increase of Reynolds number will be the decrease in friction factor and after a interval the friction factor will remain constant.

e/D = Relative roughness of pipe

EXTRUSION LINEEXTRUSION LINE

EXTRUSION LINE IS INVOLVE IN THE EXTRUSION LINE IS INVOLVE IN THE PROCESS OF PIPE MANUFACTURING.PROCESS OF PIPE MANUFACTURING.

Methods of bending pipesMethods of bending pipes

Bending Methods For Bending Pipe Bending Methods For Bending Pipe and Tubeand Tube : :

Ram Style Bending:Ram Style Bending:

Ram style bending is the Ram style bending is the simplest and cheapest method of bending pipe simplest and cheapest method of bending pipe and tube.  The pipe or tube is restrained at two and tube.  The pipe or tube is restrained at two eternal points and the ram advances on the eternal points and the ram advances on the central axis and deforms the pipe.central axis and deforms the pipe.

Mandrel Bending:Mandrel Bending: Mandrel bending of pipe and tube is used where Mandrel bending of pipe and tube is used where

the bent pipe and tube are to have absolutely the the bent pipe and tube are to have absolutely the least amount of deformation possible.least amount of deformation possible.

The pipe and tube is supported internally The pipe and tube is supported internally with a flexible mandrel support that bends with the with a flexible mandrel support that bends with the pipe or tube, and ensures that the interior is not pipe or tube, and ensures that the interior is not deformed. The pipe or tube is drawn through a deformed. The pipe or tube is drawn through a counter bending die onto fixed radius former die, counter bending die onto fixed radius former die, and the hole process ensures the best possible and the hole process ensures the best possible bends.bends.

Rotary Draw Bending:Rotary Draw Bending:

This is the most commonly used style of This is the most commonly used style of bender for bending pipe and tube where bender for bending pipe and tube where maintaining a good finish and constant maintaining a good finish and constant diameter is important.diameter is important.

The pipe or tube is drawn through The pipe or tube is drawn through stationary counter- bending die onto fixed stationary counter- bending die onto fixed radius former die.radius former die.

Ring Roll Bending:Ring Roll Bending: Ring roll Bending is used for bending pipe Ring roll Bending is used for bending pipe

and tube to large Center Line Radius, i.e. and tube to large Center Line Radius, i.e. to large circumferences. to large circumferences.

Pipe and tube ring roll benders Pipe and tube ring roll benders comprise 3 rolls on separate shafts that comprise 3 rolls on separate shafts that roll the pipe through the rolls while the top roll the pipe through the rolls while the top roller exerts downward pressure on the roller exerts downward pressure on the top roll to deform the pipe. top roll to deform the pipe. 

Forces acting on Forces acting on pipe bendspipe bends

Resulting force due to Mass flow and Resulting force due to Mass flow and Flow Velocity:Flow Velocity:

The resulting force in x-direction due to mass flow The resulting force in x-direction due to mass flow and flow velocity can be expressed as:and flow velocity can be expressed as:

Rx = m v (1 - cosβ)         Rx = m v (1 - cosβ)                 = ρ A v2 (1 - cosβ)        = ρ A v2 (1 - cosβ)                = ρ π (d / 2)2 v2 (1 - cosβ)       = ρ π (d / 2)2 v2 (1 - cosβ)       

The resulting force in y-direction due to mass flow The resulting force in y-direction due to mass flow and flow velocity can be expressed as:and flow velocity can be expressed as:

Ry = m v sinβ        Ry = m v sinβ                = ρ A v2 sinβ        = ρ A v2 sinβ                = ρ π (d / 2)2 v2 sinβ            = ρ π (d / 2)2 v2 sinβ           

The resulting force on the bend due to force in x- The resulting force on the bend due to force in x- and y-direction can be expressed as:and y-direction can be expressed as:

R = (Rx2 + Ry2)1/2        R = (Rx2 + Ry2)1/2        

Resulting force due to Static PressureResulting force due to Static Pressure

The pressure and the end surfaces of the bend creates The pressure and the end surfaces of the bend creates resulting forces in x- and y-directions.resulting forces in x- and y-directions.

The resulting force in x-direction :The resulting force in x-direction : Rpx = p A (1- cos β)             Rpx = p A (1- cos β)                     = p π (d / 2)2 (1- cos β)        = p π (d / 2)2 (1- cos β)        Rpx = resulting force due to pressure in x-direction (N)Rpx = resulting force due to pressure in x-direction (N)

The resulting force in y-direction can be expressed asThe resulting force in y-direction can be expressed asRpy = p π (d / 2)2 sinβ       Rpy = p π (d / 2)2 sinβ       where where Rpy = resulting force due to pressure in y-direction (N)Rpy = resulting force due to pressure in y-direction (N)The resulting force on the bend due to force in x- The resulting force on the bend due to force in x-

and y-directionand y-direction : : Rp = (Rpx2 + Rpy2)1/2        Rp = (Rpx2 + Rpy2)1/2        

Head loss in pipe bends:Head loss in pipe bends: Minor loss is caused when there is additional component is Minor loss is caused when there is additional component is

added to the straight pipe such as tees, elbows and bend. added to the straight pipe such as tees, elbows and bend. This minor loss will contribute to head loss due to the This minor loss will contribute to head loss due to the friction across bends and elbows. friction across bends and elbows.

Bernoulli’s equation relates pressure, velocity and elevation Bernoulli’s equation relates pressure, velocity and elevation between any two points in the between any two points in the

flow. But since the equation have some restriction, a new flow. But since the equation have some restriction, a new term must be introduce. term must be introduce.

P1/ρg + V1/2g + z1= P2/ρg + V2/2g + z2 + hL P1/ρg + V1/2g + z1= P2/ρg + V2/2g + z2 + hL Head loss is added because in real life situation there are Head loss is added because in real life situation there are

losses. This situation can be proved by calculation of the losses. This situation can be proved by calculation of the drop in the flow rate. Minor losses expressed in terms of drop in the flow rate. Minor losses expressed in terms of loss coefficient, Kι and defined as:loss coefficient, Kι and defined as:

Kι = hι / (V²/ (2g). Kι = hι / (V²/ (2g).

Types of bendsTypes of bends

Short radius bend Long radius Short radius bend Long radius bendbend

Wear Resistant Pipe, Fittings and BendsWear Resistant Pipe, Fittings and Bends To achieve both technical and economical To achieve both technical and economical

wear protection, many factors have to be taken into wear protection, many factors have to be taken into account. The choice needs to be based on the account. The choice needs to be based on the application. The best solution for long life and application. The best solution for long life and economical abrasion protection depends upon the economical abrasion protection depends upon the proper selection of the wear resistant pipe linings as proper selection of the wear resistant pipe linings as well as a knowledge of expected cost.well as a knowledge of expected cost.

A wide range of different materials with A wide range of different materials with different characteristics can be chosen to protect different characteristics can be chosen to protect against wear. Pipe linings made of mineral, metallic against wear. Pipe linings made of mineral, metallic or ceramic materials have proven to work well.or ceramic materials have proven to work well.

Clear Advantages of Using Wear Resistant Clear Advantages of Using Wear Resistant Pipe Linings:Pipe Linings:

Long lifetime and maintenance free operation Long lifetime and maintenance free operation NO operation interruption or production losses NO operation interruption or production losses NO contamination of the conveyed materials due to NO contamination of the conveyed materials due to

abrasion, mixture or oxidation abrasion, mixture or oxidation Physiologically harmless, suitable for food products Physiologically harmless, suitable for food products Smooth surface to achieve good flowability and to Smooth surface to achieve good flowability and to

avoid plugs avoid plugs Reduced pressure losses and lower energy cost Reduced pressure losses and lower energy cost No spilled material to clean up No spilled material to clean up

Applications of pipes and bendsApplications of pipes and bends Pipes and bends have got applications on a large Pipes and bends have got applications on a large

scale. They are used almost everywhere in scale. They are used almost everywhere in every industry.every industry.

1.1. Pipes are used to transfer different sort of fluids Pipes are used to transfer different sort of fluids in our industries. in our industries.

Pipes and bends are used in dams and Pipes and bends are used in dams and turbines as penstocks and hollow turbines as penstocks and hollow shafts.shafts.

Have widely range of applications in Have widely range of applications in automobile industry as well.automobile industry as well.

They are also used in roof fabrication of They are also used in roof fabrication of roofs of buildings.roofs of buildings.

They are also used in many household They are also used in many household applications.applications.

Pipes are used to transfer fluids i.e Pipes are used to transfer fluids i.e gas and liquids from one place to gas and liquids from one place to another . Even from one country to another . Even from one country to other as well.other as well.