KSB pump_ Hydraulic model testing Solids transport in waste water pipes

Summary

This video demonstrates the behavior of various solids in wastewater pipelines at different flow velocities. Using a model with horizontal and vertical pipe sections, the experiment observes how broken glass, smooth and rough stones, steel parts, and mixed solids move through the system. Key findings show that particle size, shape, and density affect settling speed, with higher flow velocities required to transport solids through vertical sections. The experiment highlights how lighter or smoother particles move first, while denser or irregular-shaped solids need faster flows, providing valuable insights for designing pipelines that prevent blockages and ensure efficient solid transport.

Takeaways

• 💧 Wastewater pipelines must prevent deposition of solids such as fibers, sand, and gravel.
• 🔧 The experiment uses a model with horizontal and vertical pipes, a pump, and a collection basket to study solid transport.
• 🟢 Solids are introduced through a filler pipe into the horizontal section of the pipeline.
• ⚙️ Flow velocity is controlled using a pump and gate valves, and measured during the test.
• 🪨 Different solids behave differently based on density, size, and surface structure.
• 📈 Broken glass pieces start moving at ~0.4 m/s and are fully transported at ~0.7 m/s through the vertical riser.
• 🔵 Smooth round stones start moving at ~0.4 m/s and are fully transported at ~0.8 m/s.
• 🟤 Rough stones begin moving at ~0.45 m/s and are fully transported at ~0.8 m/s.
• 🛠️ Small metal parts start moving at ~0.6 m/s and require ~1.7 m/s for complete vertical transport.
• 🔄 Mixed solids separate during transport, with glass and stones moving first, and metal parts last.
• 📊 Vertical pipe transport requires higher flow velocities than horizontal transport.
• ⚖️ The settling speed of particles depends on size, shape, and density, with coarse, spherical particles settling faster.
• 🧩 Understanding flow velocities is essential to avoid blockages in wastewater pipelines.

Q & A

What is the main purpose of the pipeline solids transport experiment?

The main purpose is to investigate and demonstrate how different solids behave in a pipeline at various flow velocities and to understand the conditions required to prevent deposition of solids like fibers, sand, gravel, and other materials.

What does the experimental setup consist of?

The setup includes horizontal and vertical pipe riser sections, a water tank with a pump to circulate water, a metal basket to collect transported solids, measuring equipment, and gate valves to control flow velocity.

How are solids introduced into the pipeline in the experiment?

Solids are fed into the horizontal pipe through a filler pipe.

At what flow velocity do pieces of broken glass start moving in the horizontal pipe?

The pieces of broken glass start moving at approximately 0.4 meters per second.

Why do solids tend to come to rest in the bend at the base of the vertical pipe riser?

Solids come to rest at the bend due to changes in flow direction and velocity, which reduces the water’s ability to transport heavier or irregularly shaped particles.

How does the behavior of round smooth stones differ from broken glass during transport?

Round smooth stones start moving at a slightly higher velocity (0.4–0.45 m/s) and require a slightly higher velocity (0.8 m/s) to be fully transported up the vertical pipe compared to broken glass, which moves more easily at lower velocities.

What flow velocity is required to fully transport small metal parts like nuts and bolts through the vertical pipe riser?

All remaining small metal parts are transported out of the vertical pipe riser at approximately 1.7 meters per second.

What general trend is observed regarding the flow velocity needed in horizontal versus vertical pipe sections?

The flow velocity required to transport solids in vertical pipes is higher than that required in horizontal pipes due to gravity acting against upward movement.

How do mixed solids behave when transported through the pipeline?

Mixed solids separate according to density and shape; glass and stones start moving at lower velocities, while heavier metal parts require higher velocities. Some solids move along the horizontal pipe, rest at bends, and are later transported at higher flow rates.

Which factors influence the settling speed of particles in the pipeline?

The settling speed depends on particle size, shape, and density. Coarse, nearly spherical gravel settles faster than fine sand or organic fibers.

Why is understanding these flow velocities important for wastewater pipeline design?

Knowing the minimum flow velocities for different solids helps prevent clogging, ensures efficient transport, and guides the design of pumps, pipe diameters, and vertical risers to maintain proper wastewater flow.

At approximately what velocity do rough stones begin moving along the horizontal pipe?

Rough stones start moving along the horizontal pipe at approximately 0.5 meters per second.