Materials Handling and Transfer Piping Systems Piping System

Materials Handling and Transfer “Piping Systems”

Piping System Definition: Interconnected piping subjected to the same design conditions. Piping system components 1. Pipes 2. Fittings (flanges, threaded, welded) 3. Valves 4. Expansion joints 5. Strainers 6. Traps 7. Inline instruments 8. Supports (anchors)

Identification Systems ASTM System

PVC pipes take the letter D

Pipes specifications: Pipes are specified according to wall thickness by a standard formula for schedule number ØOn increasing schedule number, the pipe wall thickness increase

What is the nominal diameter? The ND code is a code that rounds off the diameter of the pipe to get an even number to work with, not the exact diameter. The American version is called NPS (Nominal Pipe Size) and is in English units. ND is the European version and is based on millimeters. For example, If you want 2" Pipe, NPS calls it 2" and ND calls it 50 mm. but the actual outside diameter is neither 2" or 50 mm. They just use these nice round numbers cause it is easier.

Pipe Sizing 1 - Wall Thickness tm: is the minimum required thickness Dm: mean diameter 2 - Optimum Diameter

Fittings and other piping auxiliaries. Are used to: A- Connect pieces of pipes together B- Change the flow direction C- Regulate the flow D- Obtain desired conditions in a flow system Types of fittings 1 - Threaded fittings( screwed) [for small size] 2 - Flanges [for diameter 3 in. ] 3 - Welding

Threaded (screwed) fittings

Threaded (screwed) fittings

Flanged fittings

Flanged fittings

Piping Systems Problems 1 - Solidification and corrosion 2 - Thermal expansion 3 - Liquid pockets

Liquid pockets They can be caused by gas/liquid getting into a liquid/gas pipe. Sometimes the pressure or temperature of the fluid within a pipe will change and that can allow phase change, or gases to escape out of a liquid, or gases to condense. e. g. Steam lines contain hot gaseous steam, but as this steam cools down, condensate(liquid water) starts forming. If water within a pipe gets hot some may boil (causes "boiler rumbling"). Carbonated drinks hold a lot gas when under pressure, when it's realized the gas/liquid separate. Air holds a fair bit of moisture, Increase it's pressure, or drop it's temperature and moisture will drop of it. Similar thing with natural gas.

Øliquid pockets can cause problems as slug of liquid can then be forced down the pipe at high speed. When it hits something, it's comes to a very quick stop. The liquid is effectively incompressible and so it's KE is converted into a VERY fast rise in pressure, and that can rupture the pipe/fitting (Water hammer).

Steam trap A steam trap is a device used to discharge condensate and non condensable gases with a negligible consumption or loss of live steam. Most steam traps are nothing more than automatic valves. They open, close or modulate automatically. The three important functions of steam traps are: ØDischarge condensate as soon as it is formed. ØHave a negligible steam consumption. ØHave the capability of discharging air and other non-condensable gases.

How to overcome the solidification problem in pipelines? Pipe Launcher

Smart Pig

Smart Pig

Smart Pig Inside the Pipe

Magnetic sensor Pipe wall Pig body

Pipe Expansion and Support ØAny piping system must be fully supported, able to expand during operation and sufficiently flexible to allow movement as a result. ØAll pipes will be installed at ambient temperature. ØPipes carrying hot fluids such as water or steam operate at higher temperatures. ØIt follows that they expand, especially in length, with an increase from ambient to working temperatures. ØThis will create stress upon certain areas within the distribution system, such as pipe joints, which, in the extreme, could fracture.

Calculation of the amount of expansion The amount of the expansion is readily calculated using Equations, or read from an appropriate chart. Expansion coefficients (α) (mm/m °C x 103)

A chart showing the expansion in various steel pipe lengths at various temperature differences

ØThe fixed or 'anchor' points 'A' provide a datum position from which expansion takes place. ØThe sliding support points 'B' allow free movement for expansion of the pipe work, while keeping the pipeline in alignment. ØThe expansion device at point 'C' is to accommodate the expansion and contraction of the pipe.

Pipe Support Chair and roller Chair roller and saddle

Expansion Fittings 1 - Full loop ØThis is simply one complete turn of the pipe and, on steam pipe work, should preferably be fitted in a horizontal rather than a vertical position to prevent condensate accumulating on the upstream side.

2 - Horseshoe or lyre loop

3 - Expansion loops Expansion loop

Expansion loop capacity for carbon steel pipes

4 - Sliding joint

5 - Expansion bellows Simple expansion bellows An expansion bellows, has the advantage that it requires no packing as does the sliding joint type.

Expansion bellows

Expansion bellows

ØBellows may incorporate limit rods, which limit over-compression and over-extension of the element.