Introduction, Types of Conduits, Types of Pressure Pipes Part 1

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Introduction, Types of Conduits, Types of Pressure Pipes Part 1

Introduction, Types of Conduits, Types of Pressure Pipes Part 1. In the vast landscape of civil engineering, the intricate network of conduits and pressure pipes forms the backbone of infrastructure projects worldwide. These essential components serve as conduits for fluids, ensuring the smooth flow of water, gases, or other substances critical for various applications. As we embark on a comprehensive exploration, it's imperative to delve into the fundamentals, unravelling the intricacies of different conduit types and pressure pipe systems.

In this inaugural instalment of our series, "Introduction, Types of Conduits, Types of Pressure Pipes," we embark on a journey through the foundational concepts that underpin these vital elements of civil engineering infrastructure. By dissecting the core principles and exploring the diverse array of conduits and pressure pipes available, we pave the way for a deeper understanding of their significance in the realm of construction and development.

Throughout this series, we aim to provide invaluable insights into the various types of conduits and pressure pipes, equipping professionals, enthusiasts, and aspiring engineers alike with the knowledge necessary to navigate the complexities of modern infrastructure projects. From traditional materials like concrete and steel to innovative solutions such as fiberglass and PVC, each type offers unique advantages and applications, shaping the landscape of civil engineering with its distinct characteristics.

Furthermore, by incorporating the most searched keywords and leveraging the latest advancements in civil engineering practices, our exploration transcends mere theoretical discourse, offering practical insights and actionable information that resonate with industry professionals and enthusiasts alike. From underground utilities to above-ground distribution systems, the significance of conduits and pressure pipes cannot be overstated, making them focal points of innovation and development in the field of civil engineering.

Join us on this enlightening journey as we unravel the complexities, explore the nuances, and celebrate the ingenuity behind conduits and pressure pipes. Together, let us embark on a quest to deepen our understanding, broaden our horizons, and forge new pathways towards a future where infrastructure stands as a testament to human progress and innovation.

What is Conduits?

  1. Water supply system consists of various components such as sources of water supply, treatment plants, and distribution networks.
  2. For carrying or transporting water from one component to another, we need conduits.
  3. Conduits may be either open or closed type, it depends on the weather energy is provided by gravity or by pumps.
    Examples: Open channels, tunnels, and pipelines.
  4. Open channels are designed to convey water under the condition of atmospheric pressure.
  5. Pressure tunnels are constructed to cross rivers and valleys.
  6. Pipelines usually follow the profile close to the ground quite closely.
  7. Pipelines may require different valves, joints, manholes, and pumping stations.

types of conduits

Depending upon characteristics and conditions of flow, the conduits may be classified into:

1. gravity conduits:-

  • a) Water flows under a mere action of gravity.
  • b) The hydraulic gradient line will coincide with the water surface and will be parallel to the bed of the conduits.
  • c) Gravity conduits can be in the form of the following:
    • i) Canals
    • ii) Flumes
    • iii) Aqueducts

2. pressure conduits:-

  • a) The water flows under pressure above atmospheric pressure.
  • b) The hydraulic gradient line is obtained by joining water surface elevations in piezometers installed in conduits at various places.
  • c) Pressure conduits can follow the natural available ground surface and can go freely up and down hills, thus requiring a lesser length of the conduit.
  • d) The major head loss caused by pipe friction can be found in the following formulas:
    • Darcy - Waisbach Formula
      • hf = f x l x v2
        • f = coefficient of friction
        • l = length of pipe
        • v = velocity of water
    • Manning's Formula
      • V = (1/n) x R2/3 x S1/2
        • R = Hydraulic radius
        • S = Slope
    • Hazen - William's Formula
      • V = 0.85 x CH x R0.63 × S0.54
        • C, is the coefficient of hydraulic capacity.
        • CH has dimension of L-0.37 T-1
        • Smoother the pipe, the greater the value of CH
        • S is the slope of the energy line.
      • Modified Hazen-William's Formula
        V = 143.53 x CR x R0.6575 x S0.5525
        Where CR = Dimensionless coefficient of roughness.

types of pressure pipes

1. metallic pipes:-

  1. Unlined Metallic Pipes.
  2. Metallic Pipes lined with cement Mortar.
    • The following types of Metal pipes are used:
      • i) Cast Iron pipes.
      • ii) Steel pipes
      • iii) Wrought Iron pipes
      • iv) Copper, Lead, and Brass pipes.

    2. non-metallic pipes:-

    • Reinforced concrete, Prestressed concrete, asbestos cement.
    • Plastic pipes: PVC, Polyethene, Glass Reinforced Plastic, etc.

    Important notes:-

    Normally, the design period of pipelines is considered 30 years

    metallic pipes:-

    1. Cast Iron Pipes:-

    1. Most widely used in water supply for a drink as well as distributary mains.
    2. Manufactured by two methods:
      • i) Sand Moulding
      • ii) Centrifugal Process.
    3. McWane pipes are cast by sand moulding in a horizontal position.
    4. Pit Cast pipes are cast by sand moulding in a Vertical position.
    5. Horizontally cast pipes are 100% stronger in Tension and 50 % stronger in rupture than vertically casted pipes.
    6. Cl Pipes are not used for pressure > 700 KN/m2.
    7. These pipes have a long life up to 100 years or so, consequently, they are strong, durable, and easy to join.
    8. To prevent corrosion, they are generally coated with a bituminous layer. Larger sizes may be provided with cement mortar (1:2) lining, whereas smaller sizes for those used in water supply distribution are coated with zinc.

    2. Steel Pipes:-

    1. Used as water mains passing over bridges and culverts of longer spans.
    2. Such steel pipes having a coating of cement mortar from inside as well as outside are known as Hume steel pipes.

    3. wrought iron Pipes:-

    1. Due to easy workability, they are used for water distribution lines inside the building (Service Connection).
    2. These pipes are liable to be affected by acidic and alkaline water.

    4. copper, lead and brass Pipes:-

    1. Copper pipes are used in acidic and alkaline environments as they are highly resistant to acid and alkalis.
    2. Copper pipes are used for carrying hot water inside buildings and factories.
    3. Brass pipes are harder than copper pipes and are used for decorative plumbing.
    4. Lead pipes are more common in sanitary plumbing.

    non- metallic pipes:-

    Most commonly used non-metallic pipes are:

    1. prestressed concrete Pipes:-

    1. They can be made to withstand higher pressure.
    2. Prestressed concrete pipes are cheaper than other pipes above 300 mm. in diameter.
    3. They are also corrosion-resistant.

    2. Reinforced Cement concrete pipes:-

    1. Mostly used as water mains.
    2. They are available in diameters from 200 mm to 1800 mm.
    3. Longitudinal reinforcement is 0.25% of the gross area of concrete.

    3. Vitrified Clay pipes:-

    1. Not used for pressure pipes.
    2. Extensively used for carrying sewage.

    4. asbestos pipes:-

    1. Silica and cement are converted under pressure to a stiff material called asbestos.
    2. Asbestos pipes are not suitable for use in sulphate soil.
    3. They are highly resistant to corrosion.
    4. They are flexible and may permit 12o deflection.

    points to remember

    • Cast iron and ductile iron pipes are joined by socket and spigot joints.
    • Cast iron pipes have socket/spigot ends suitable for lead caulked joints and ductile iron pipes suitable for mechanical joints.
    • PCC pipes are used for low head up to 15 m, and RCC for medium head up to 75 m and Pre-stressed Concrete for a high head.

    forces acting on pressure conduits:-

    1. The structural design of the pressure pipe should be carried out, so as to enable them to withstand the various forces likely to come on them.
    2. The following forces generally come into play in the pressure conduits.
      • Internal pressure of water including water hammer pressure to be resisted by using material strong in tension.
      • Pressure due to external loads in the form of backfill, traffic load, etc., to be resisted by using material strong in compression.
      • Longitudinal stress created due to unbalanced pressure at bend, or at points of change of cross-section to be resisted by holding the pipe firmly by anchoring in massive blocks of concrete or stone masonry.

    Disadvantages of steel pipes:-

    • The steel pipes are likely to be rusted by slightly acidic or alkaline water. The outside earth in contact with these pipes also helps in the process of rusting pipes in some cases. The rivets used in the joints for these pipes form the nucleus for the process of rusting.
    • The maintenance cost of these pipes is high.
    • These pipes require more time for repairs during a breakdown, and hence, these are not suitable for distribution pipes.
    • These pipes cannot withstand high negative (or vacuum) pressures.
    • The steel pipes are likely to deform in shape under the combined actions of external and internal loads.

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