The Palmer-Bowlus flume is well know in the sanitary field, and has been used in the Los Angeles area for over 60 years. It’s primary application is in pipelines, in round bottom channels or in manholes where it is often preferred because of cost and ease of installation that can minimize construction expense.
The Palmer-Bowlus flume should always be used on a same size or larger pipeline or channel. Placing the flume on a smaller sized line greatly increases the probability of inlet turbulence or submergence and reduces the upper range of flow to less than the full pipe capacity of the smaller line. With a normal downstream water tail condition the Palmer-Bowlus flume will give accurate free flow readings up to 80-85 percent submergence. Numerous standard variations are used to help solve flow and installation problems.
- Palmer-Bowlus with Approach – 4D + 1″ length – often called “Permanent Type”, is the most common. An integral Head Gage is correctly located in the approach section to simplify setup and installation of continuous monitoring instruments. In poorly defined channels the approach section helps to “smooth out” the approaching flow.
- Short Section Palmer-Bowlus with Approach – 3D + 1″ length – includes the Head Gage and can often be used in straight, well defined channels having the same “D” dimension as the flume where space is an issue.
- Palmer-Bowlus without Approach – 2D + 2″ length – may be permanently installed in straight, well defined channels having the same “D” dimension as the flume. Flow monitoring equipment must be independently located at the correct measuring point in front of the flume and must be accessible.
- Palmer-Bowlus Insert Flume – 2D + 2″ length – may be used for temporary or permanent installation in same size straight-line channels with smooth well defined dimensions. “D” equals the flume O.D. on Inserts. This makes it possible to set the flume into a pipe having the same I.D. without being “pinched”. A gage is not included.
- Palmer-Bowlus Cutback or “Exit Type”– 2D + 2” length – is similar to the Insert flume but the top half of the downstream straight wall is cutaway so the flume can be slipped into the downstream pipe. Again the flume I.D. and pipe O.D. must match. Flow accuracy in the upper flow range may be affected.
- Palmer-Bowlus RT (rubber tire) flumes are available for temporary flow studies and can be purchase in sizes from 4″ to 12″ diameter.