Storm sewer discharges
Industrial process discharge
Irrigation water
Holding pond overflow

Palmer-Bowlus flumes are available with various approach section lengths. In applications where a full approach section is not integral to the flume, the upstream piping forms the approach section. Free Flow's standard flume
lengths are as follows:

Fabricated in one piece
Consists of throat section with floor section and side ramps.
Edges of ramps feathered to allow an installation resulting in smooth transition surfaces.
Designed to be installed into lower half of existing pipe. Secured in place with epoxy.
Depth measurements are made in upstream piping.
Reduced discharge capacity due to limited sidewall height.

Fabricated in one piece
Consists of end & top flanges, throat section with sidewalls.
Depth measurements are made in upstream piping.

Palmer-Bowlus Flume 2.5D Length (Actual length = 2.5D + 6")

Fabricated in one piece
Consists of end & top flanges, throat section, and short upstream approach
section to allow an attached stilling well, bubbler tube, head gauge, or sensing element cavity.
Available with pipe stub end with either flat face fiberglass pipe flanges or neoprene couplings & SS band clamps.
Depth measurements are made in the integral approach section of flume.
Stilling wells, depth gauges & bubbler tubes can be provided with this flume.

        Fabricated in one piece
        Consists of end & top flanges, throat section, and full upstream approach           section to allow an attached stilling well, bubbler tube, head gauge, or
        sensing element cavity.
        Available with flat face fiberglass pipe flanges or neoprene couplings with           pipe stub ends.
        Depth measurements are made in the integral approach section of flume.

Palmer-Bowlus Cutback (Exit Type) Flume

Palmer-Bowlus flumes can have the downstream upper sidewalls cut back to allow the flume to be partially inserted in a pipe leaving a manhole. Allows the use of a longer or larger flume in confined areas and facilitates installation. An optional bulkhead to help make a watertight seal is available. The following flumes can have a cutback modification: 2D+2", 2.5D+6", 4D+1".

Free Flow Palmer-Bowlus Flume, Model SC, Standard Construction

Model SC Flumes are intended for below grade installation in concrete with the
following features:

Fabricated from reinforced polyester fiberglass with white gel-coat finish on wetted surfaces to enhance the self scouring properties of the flume.
Gel-coat finish on all exterior surfaces to prevent deterioration due to UV exposure.
1/4 inch minimum wall thickness for rigidity.
Integral "V" type ribs on exterior.
Removable fiberglass crossbraces across top to maintain dimensional accuracy.

Free Flow Palmer-Bowlus Flume, Ruggedized Construction

Model RC flumes are intended for free standing, above grade applications. Support is only required at intermediate points on the underside. Model RC flumes allow quick installation with minimal down time and field installation costs. Model RC flumes have the same features as SC with:

Additional "V" ribs on exterior
Heavier wall & flange thickness
Additional crossbracing on top of flume
Wider end and top flanges for greater rigidity

Free Flow Palmer-Bowlus Flumes, Special Materials Construction

SMC construction provides enhanced resistance to specific chemicals and
elevated temperatures.

304 or 316 stainless steel construction
Vinyl ester or other special gel-coats & resins

Free Flow Palmer-Bowlus flumes are available with optional accessories to facilitate
their installation and use.  Options include:

Head Gauge
Free Flow head gauges allow the discharge of the flume to be checked at any instant.
          Flush mounted in flume at time of manufacture.
          Fabricated with a clear 1/16" fiberglass laminate to gauge markings.
          Gauge markings in depth. Units: Feet, by 1/10th & 1/100th Ft.
          Head gauges are located at D/2 upstream from the throat ramp.
          Gauge zero elevation to correspond to "wet zero".
          Gauge markings on curved section of flume wall have elongated markings              to result in correct depth readings.

Anchor Clips
Fiberglass anchor clips on the flume exterior allow flume floor & sidewalls to be wired to surrounding reinforcing bars, or other anchoring points, to secure flume in place to insure proper alignment after installation.

Stilling Wells
Free Flow attached stilling wells provide a calm water surface where depth measurements may be taken with greater accuracy.  Stilling wells permit the
most accurate depth measurements possible, especially in larger size flumes.  Attached stilling wells allow the shortest connecting passage possible to prevent plugging of the port.  Stilling wells are fabricated with the same materials & finish as the flume with a top flange for mounting brackets for depth transducers.
Stilling wells extend below the floor of the flume to insure that the depth in the well reflects the actual depth in the flume and an optional bottom drain on well facilitates well cleaning.   Standard well sizes available: 8" dia. or 12" dia.

Stilling Well Connections & Remote Stilling Wells
A stilling well connection consists of a pipe stub NPT connection to allow piping to a remote well or an oversized stilling well.  The standard stilling well connection is 304 stainless steel 2" Male NPT threaded pipe nipple.  A remote stilling well will have the same material and construction to match the flume's construction.

Inlet & Outlet Pipe Connections

Pipe connections on the inlet & outlet of Palmer-Bowlus flumes provide a quick and efficient means to obtain a watertight installation. Several styles of pipe end connections are available: