Like the Palmer-Bowlus flume - which it is a type of - the Lagco flume was specifically designed to measure the flow of sewage and other wastestreams in circular pipes, conduits, and channels.
The Lagco flume can be used on either a temporary or permanent basis - although temporary installations have become less common with the advent of low profile area velocity sensors as well as radar and laser based flow meters. Lagco flumes have been used to measure industrial discharges, municipal sewer flows, and influent / effluent flows at wastewater treatment plants.
Lagco Flume Accessories
As with our Palmer-Bowlus flumes, Openchannelflow offers a range of accessories to assist you in customizing your Lagco flume. In general, the accessories offered are one of four types:
Piping / end connections
Flow condition options
Flow meter mounts
Sampler / parameter mounts
Custom configurations (nesting, surge boxes, etc.)
Lagco flumes are not offered with extended sidewalls.
Lagco Flume Applications
Typical Lagco flume installations:
- Wastewater treatment plants flows
- Sewage collection systems
- Industrial pre-treatment discharges
- Seepage monitoring at dams
- Cross jurisdiction flows
The Lagco flume utilizes both vertical and lateral restrictions of the flow stream - reducing the flow area in throat of the flume to increase flow velocity. As with the Palmer-Bowlus flume, the Lagco flume has a raised throat ramp (D/6 tall). The sidewalls, however, are vertical contractions versus the trapezoidal contractions of the typical Palmer-Bowlus layout. The flume has a U-shaped cross section to minimize the transition of flow through the flume.
The result is that flow is accelerated through the throat by the combination of change in floor elevation and vertical constriction of the sidewalls. Unlike the more common Parshall flume, there is no need to accommodate a change in elevation. Both the inlet and outlet of the Lagco flume are at the same elevation.
As with other flumes (i.e. Cutthroat, Palmer-Bowlus, RBC), the design of the Lagco is dimensionless, with each flume size based upon a standard design. The dimensions for a Lagco rely on only one dimension, D - the channel width. Once D is know, all other dimensions of a Lagco flume can be determined.
variations of tHE LAGCO flume:
- Permanent Style with Integral Approach
- Permanent Style without Approach
- Insert Style
- Cutback (Insert) Style
Each variation serves a particular purpose. For a more in depth discussion of the various Palmer-Bowlus styles, their layouts and applications, refer to the Dimensions section of this site.
The point of measurement in a Palmer-Bowlus flume is located a distance D/2 upstream of the beginning of the throat ramp (where D is equal to the flume size).
Palmer-Bowlus flumes are of the Long-Throated type. As a result, they can be calculated by computer analysis (versus Short-Throated flumes like the Parshall which are empirical devices and must be laboratory calibrated).
Over the years 18 sizes of Palmer-Bowlus flume have been marketed, with throat sizes from 4 to 72-inches. In practice, it is rare to see Palmer-Bowlus flumes in sizes above 24-inches.
The Lagco flume was researched in the early 1960s and introduced in 1965 by the F.B. Leopold Company, Inc. Palmer-Bowlus flume is the result of the investigations started in the 1930's by two engineers of the Los Angeles County Sanitation Department, Harold Palmer and Fred Bowlus, into adapting Venturi flumes for use in sanitary sewers.
The goal of their investigations was to develop a simple, low cost flume that adapted easily to the round pipes and U-channels found in sanitary sewer applications.