What is the relationship between vertical lift and velocity for water sampling?
As the vertical lift (the vertical distance between the level of the water source and the water sampler’s pump) increases, the speed of the fluid through the sampling system decreases. Consequently, greater speed is needed to compensate for a larger gain in height and to preserve a more representative sampling of large particles and suspended solids. To maintain the necessary velocity, a larger pump may be required.
In general, the following statements are true regarding vertical velocity:
- Increasing the inner diameter of the tubing decreases the velocity. (The larger the tubing, the slower the fluid flows.)
- Decreasing the pump power decreases the velocity. (The smaller the pump, the slower the fluid flows.)
- Increasing the vertical lift decreases the velocity. (The higher the fluid needs to travel, the slower the fluid flows.)
- Increasing the altitude at which the water sampler is located decreases the velocity. (The higher the altitude, the slower the fluid flows.)