Parshall Flumes Solutions
Parshall flumes are the most widely used type of flume in the industry. Developed in 1922 by Ralph L Parshall, the Parshall flume was designed for the United States Bureau of Reclamation. Then it was used for permanent flow monitoring installations. Today, it does the same, however includes many options and accessories and is used for many reasons.
Options & Accessories
TRACOM has worked with various wastewater management companies across the world for over 30 years. We understand that each system is different and needs various items to run most efficiently. This is why we provide a long list of options and accessories for Parshall flumes. Contact a specialist today to see which options work best for your company’s needs!
- Ultrasonic mounting brackets
- Bubble tubes
- Sample tubes
- Submerged probe cavities
- Stilling wells (attached and detached)
- Staff gauges
- Removable probe holders
- Inlet and outlet end adapters
- Pipe stubs
Flanged end connections - Flow straighteners
- Fiberglass grating
- Inlet and outlet wingwalls
- Multi-piece construction
- Nesting
- Chemically resistant gel coal
Benefits
- Wide Flow Ranges
- Resistance to Submersion
- Simple Flow Meter Calibration
- Self-Cleaning Design
Applications
- Sewage Treatment Plant Influent and Effluent
- Industrial Process Discharge
- Irrigation and Agricultural Runoff
- Dam Seepage
- Watershed Monitoring
Contact Us
Related Blogs
Free vs Submerged Flow in Parshall Flumes
When you have a Parshall flume, one of the most important factors is being able to recognize the difference between free flows and submergence. While …
Frequently Asked Questions
A Montana flume is essentially a shortened Parshall flume. It removes the throat and discharge section of the Parshall, allowing the same measurement options as a Parshall, at more than half the length. The downside is that a free-flow drop is recommended, as pipe stubs cannot be installed onto a Montana.
Tracom sells Parshall flumes. We make 1″, 2″, 3″, 6″, 9″, 12″, 18″, 24″, 30″, 36″, 48″, 60″, 72″, 84″, 96″, 120″, and 144″ sizes. The Parhsall flume size refers to the width of the flume at the throat section.
Technical Details
| Size & Style | Recommended Flow Rates |
|---|---|
| 1” | 2 – 85 GPM |
| 2” | 3 – 210 GPM |
| 3” | 4 – 834 GPM |
| 6” | 22 – 1,754 GPM |
| 9” | 40 – 3,979 GPM |
| 12” | 146 – 7,336 GPM |
| 18” | 227 – 11,021 GPM |
| 24” | 296 – 14,853 GPM |
| 30” | 366 – 18,721 GPM |
| 36” | 434 – 22,618 GPM |
| 48” | 567 – 30,484 GPM |
| 60” | 995 – 38,426 GPM |
| 72” | 1,181 – 46,431 GPM |
| 84” | 1,828 – 54,489 GPM |
| 96” | 2,076 – 62,591 GPM |
| 120” | 2,575 – 162,414 GPM |
| 144” | 3,057 – 275,541 GPM |
| Note: 1” and 2” Parshall flumes are not recommended for sanitary flows | |
- 1 inch Parshall Flume Discharge Table
- 2 inch Parshall Flume Discharge Table
- 3 inch Parshall Flume Discharge Table
- 6 inch Parshall Flume Discharge Table
- 9 inch Parshall Flume Discharge Table
- 12 inch Parshall Flume Discharge Table
- 18 inch Parshall Flume Discharge Table
- 24 inch Parshall Flume Discharge Table
- 30 inch Parshall Flume Discharge Table
- 36 inch Parshall Flume Discharge Table
- 42 inch Parshall Flume Discharge Table
- 48 inch Parshall Flume Discharge Table
- 60 inch Parshall Flume Discharge Table
- 72 inch Parshall Flume Discharge Table
- 84 inch Parshall Flume Discharge Table
- 96 inch Parshall Flume Discharge Table
- 120 inch Parshall Flume Discharge Table
- 144 inch Parshall Flume Discharge Table
- 180 inch Parshall Flume Discharge Table
- 1 inch Parshall Flume with 4 inch Stubs
- 1 inch Parshall Flume
- 2 inch Parshall Flume with 4 inch Stubs
- 2 inch Parshall Flume with 6 inch Stubs
- 2 inch Parshall Flume with 8 inch Stubs
- 2 inch Parshall Flume
- 3 inch Parshall Flume with 6 inch Stubs
- 3 inch Parshall Flume with 8 inch Stubs
- 3 inch Parshall Flume with 10 inch Stubs
- 3 inch Parshall Flume
- 6 inch Parshall Flume with 8 inch Stubs
- 6 inch Parshall Flume with 12 inch Stubs
- 6 inch Parshall Flume with 15 inch Stubs
- 6 inch Parshall Flume with 18 inch Stubs
- 6 inch Parshall Flume with Nested 2 inch Parshall Flume
- 6 inch Parshall Flume with nested 3 inch Parshall Flume
- 6 inch Parshall Flume
- 9 inch Parshall Flume Nested in 48 Inch Parshall
- 9 inch Parshall with 12 Inch Stubs
- 9 inch Parshall with 18 inch Stubs
- 9 inch Parshall with 24 Inch Stubs
- 9 inch Parshall Flume with nested 3 Inch Parshall Flume
- 9 inch Parshall Flume
- 12 inch Parshall Flume with 18 Inch Stubs
- 12 inch Parshall Flume with 30 Inch Stubs
- 12 inch Parshall Flume with Nested 3 Inch Parshall
- 12 inch Parshall Flume with Nested 6 Inch Parshall
- 12 inch Parshall Flume with Nested 9 Inch Parshall
- 12 inch Parshall Flume
- 18 inch Parshall Flume with 36 Inch Stubs
- 18 inch Parshall Flume with Nested 9 Inch Parshall
- 18 inch Parshall Flume
- 24 inch Parshall Flume with 36 Inch Stubs
- 24 inch Parshall Flume
- 30 inch Parshall Flume
- 36 inch Parshall Flume
- 48 inch Parshall Flume
- 60 inch Parshall Flume
- 72 inch Parshall Flume
- 84 inch Parshall Flume
- 96 inch Parshall Flume
- 144 inch Parshall Flume
- Parshall Flume Master Dimensions
- Parshall Flume with End Adapters Master Dimensions
Flumes are specially shaped, engineered, and static piece of equipment that restrict flow causing an acceleration. This restriction of flow creates a relationship between the fluid level in the flume and the rate of flow allowing for easy sight measurement.
Flumes accelerate fluid from a subcritical flow to a critical or supercritical flow through a few different methodologies:
- Constricting the side walls of the flume.
- Creating slope by manipulating the floor.
- A combination of the above.
Once at a critical or supercritical flow a single head measurement can be used to determine the rate of flow at a single, defined point, notated as Ha. The relationship of fluid level at Ha and rate of flow can be either calculated through theory and formula (long-throated) or determined through lab testing (short-throated).
Accuracy of Flumes
Under perfect conditions flumes can be accurate within + (2-5%). Once installed, field conditions can cause accuracy to be closer to + 10%. These are similar accuracies to other open channel flow measurement devices such as wiers.
Advantages of Flumes
While both weirs and flumes measure open channel flow, flumes have some clear advantages.
- Measure higher rates of flow.
- Less head loss.
- Easily pass debris.
- Smaller footprint
- Available in many styles and sizes
- Easier to maintain
- More resistant to downstream effects such as submergence.
Classes of Flume
Depending on the style of flume, each of these sections will have a different shape and proportion. The key difference lies in the type of throat, thus breaking flumes into two classes:
- Long-throated Flumes – Control the rate of flow with a throat long enough to create a laminar flow while still contained within the throat section. By creating a laminar flow, the discharge rate of long throated flumes can be calculated using fluid mechanics concepts and Ha can be measured anywhere above the throat section of the flume.
- Short-throated Flumes – A bit of a misnomer, short-throated flumes may actually be quite large in specified length. They control the flow rate in a curvilinear manner rather than laminar-ly. Due to their curvilinear nature, each style and size of flume has its own highly specific relationship between rate of flow and Ha. Unlike their long-throated counterparts, each style and size of short throated flume has their own set point of measurement Ha. Calibration for this class of flume has been done empirically using other more accurate flow measurement devices to create each flumes discharge table.
Most flumes have the same 3 basic sections.
Converging section
This section funnels subcritical flow (FLOW MUST BE SUBCRITICAL) into the throat section.
The point of measurement is in this section for all types of flumes. This point is fixed for short throated flumes while variable for long throated flumes
Throat section
Further constricting flow and accelerating it from subcritical to critical or supercritical, this section is essential for the proper functioning of the flume. It is here where the most drastic construction of the sidewalls and elevation changes occur.
Diverging section
Now that the fluid is at a supercritical flow, it can potentially cause downstream scour and erosion. It is the job of the diverging section to slow the flow and help protect the downstream channel.
Note that not all flumes have this section, most notably the H-style and Montana Flumes. These two styles are recommended to discharge vertically into a collection bowl or a pool.
