To Measure Rate of Flow in Open Channels
FIBERGLASS REINFORCED POLYESTER for Corrosion ResistanceAlso available in STAINLESS STEEL
P A R S H A L L F L U M E S
For the Finest inCorrosion Resistant Equipment,
Look to Plasti-Fab.®
P A R S H A L L F L U M E S
• Maintenance Free• Dimensionally Stable• Easily Installed• Lightweight• Accurate• Economical
Bul. PF2.1
ACCURATE, ECONOMICAL, LONG-LASTINGFRP flumes are more rugged and cost less thanstainless steel, plus they’re more accurate anddurable than concrete.
THREE FLOATWELL OPTIONSFlumes are available with a 2" threadedconnection on either side for installation with aseparate floatwell or bubbler system.
A second option is an attached floatwell, sized 12"or 8", and attached to either side of the flume.
Plasti-Fab’s remote floatwell is the third option. A 2" threaded tap is provided on the flume andfloatwell for interconnecting piping, and a 1" blow-out connection is also provided on the well.
HEAD GAUGESSupplied on all Plasti-Fab flumes, the head gaugeis molded into the side of the flume during thefirst stage of construction, ensuring a smoothside-wall surface.
FRP grating provides safety on our larger flumes.
We have the right flume for you.
This small flume is removableduring the peak season at afood processing plant.
Abrasive flows at a copper mineare no problem for a flume
lined with 1⁄4" of natural rubber.
Double flumes aredesigned to accepthigher flow rates inthe future.
PARSHALL FLUMESPARSHALL FLUMES
Made to order. This flume was built to fit theunique piping of a pulp mill.
CORROSION RESISTANTFiberglass Reinforced Polyester (FRP) providesmaximum protection against chemical attack bycorrosive liquids.
WIDE RANGE OF SIZESSizes to fit your specific needs.
DIMENSIONALLY STABLEPrefabricated Plasti-Fab Parshall Flumes assuredimensional accuracy.
EASY INSTALLATIONOur lightweight, high-strength flumes are heavilyribbed for equal effectiveness in free-standinginstallations or as liners in concrete.
CLEAN WHITE SMOOTH SURFACESMinimize build-up of all types of organisms.
RUGGED CONSTRUCTIONBuilt with 2" flanges on ends and top, and heavyangle bracing across top flanges.
Designed to fit into a systemof double-wall piping, this
flume features a spill-containment structure.
FREE FLOW-MGD
84'' 6'' 12'' 24'' 48'' 72'' 120''3'' 9'' 18'' 36'' 60'' 96''144''
.01 1 1.0 10 100
25
20
15
10
5
0
HA
INC
HES
1''
2''
STANDARD DEPTH OR SPECIAL DEPTH Plasti-Fab Parshall Flumes are available in all of the dimensionsshown on the back page. Flumes requiring more or less depththan those shown can be custom built at an additional cost.
SHORT SECTION FLUMESThis space-saving design omits the diverging section (the partdownstream from the throat) without affecting the Parshall flume’saccuracy. Our short section flumes are available at no extra cost,and many engineers have found them to be an excellent problem-solving option.
The purpose of the diverging or exit section of a flume is to reducehead loss through the flume and reduce downstream erosion(which can be very important in many installations includingirrigation). Without the diverging or exit section, a flume’s flowmeasurement system remains intact.
FREE FLOW vs SUBMERGED FLOWIn the free flow condition, the downstream water level doesnot affect the level of the water upstream.
Technically speaking, in free flow the flow of water passesthrough critical depth, usually near the flume crest (theentrance to the throat).
In the submerged flow condition, the tail water depth issufficiently high to affect the upstream depth, and it istherefore necessary to measure head at two places in theflume to determine the flow (Ha and Hb).
The point at which the flow changes from free flow tosubmerged flow is called transition submergence and isexpressed as a percentage, which is the ratio Hb/Ha. In therange of sizes from 1 inch to 8 feet, this ratio varies from55% to 78%. In all sizes above 10 feet, transitionsubmergence is 80%.
Recent work has produced easy-to-use free flow andsubmerged flow calibration curves for each of the standardsizes of flumes. (Source: Utah Water Lab.) Whileinstrumentation is now available to record submerged flowelectronically, Plasti-Fab engineers encourage our clients todesign for free flow whenever possible.
Special fitting situations often require custom appendages.
A built-in energyabsorber andtranquilizing rackaccomplish both slowing and calming offast-moving inlet water.
A flume with a view! The clear polycarbonatecover permits flowobservation at asemiconductor plant.
While FRP isstandard, all of our sizes areavailable instainless steel.
FREE FLOW DISCHARGEThe discharge graph on this page is for free flow conditions only anddoes not apply in cases of submerged flow. As a rule of thumb, a freeflow condition exits if the level at the downstream gauging point doesnot exceed 2/3 of the level of the upstream gauge, when both aremeasured above the crest of the flume.
W A 2/3A or B C D E F G H J K2/3( W / 2+4)
1" 1'-29/32" 0'-917/32" 1'-2" 0'-321/32" 0'-619/32" 0'-9" 0'-3" 0'-8" 0'-93/4" 11/8" 3/4"
2" 1'-45/16" 0'-107/8" 1'-4" 0'-55/16" 0'-813/32" 0'-9" 0'-41/2" 0'-10" 0'-97/8" 111/16" 7/8"
3" 1'-63/8" 1'-01/4" 1'-6" 0'-7" 0'-103/16" 2'-0" 0'-6" 1'-0" 2'-1" 21/4" 1"
6" 2'-07/16" 1'-45/16" 2'-0" 1'-31/2" 1'-35/8" 2'-0" 1'-0" 2'-0" 2'-3" 41/2" 3"
9" 2'-105/8" 1'-111/8" 2'-10" 1'-3" 1'-105/8" 2'-6" 1'-0" 1'-6" 2'-9" 41/2" 3"
12" 4'-6" 3'-0" 4'-47/8" 2'-0" 2'-91/4" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
18" 4'-9" 3'-2" 4'-77/8" 2'-6" 3'-43/8" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
24" 5'-0" 3'-4" 4'-107/8" 3'-0" 3'-111/2" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
30" 5'-41/4" 3'-63/4" 5'-3" 3'-6" 4'-63/4" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
36" 5'-6" 3'-8" 5'-43/4" 4'-0" 5'-17/8" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
48" 6'-0" 4'-0" 5'-105/8" 5'-0" 6'-41/4" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
60" 6'-6" 4'-4" 6'-41/2" 6'-0" 7'-65/8" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
72" 7'-0" 4'-8" 6'-103/8" 7'-0" 8'-9" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
84" 7'-6" 5'-0" 7'-41/4" 8'-0" 9'-113/8" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
96" 8'-0" 5'-4" 7'-101/8" 9'-0" 11'-13/4" 3'-0" 2'-0" 3'-0" 3'-3" 9" 3"
120" 14'-31/4" 6'-0" 14'-0" 12'-0" 15'-71/4" 4'-0" 3'-0" 6'-0" 4'-6" 1'-11/2" 6"
144" 16'-33/4" 6'-8" 16'-0" 14'-8" 18'-43/4" 5'-0" 3'-0" 8'-0" 5'-6" 1'-11/2" 6'
FLUME DETAILS NOT
SHOWN IN THIS DRAWING:
(1) 2" Side and bottom ribs whichprovide rigidity.
(2) Top cross ties or temporarywood stiffeners.
(3) 2" side clips for anchoring inconcrete
®
OPTIONAL INTEGRALFLOAT WELL
2" FLANGE ALLAROUND
FLOW2/3AA
D
W C
B F G
H
K
E
J
GAGE
HaHb
• FLOW MEASUREMENT FLUMES
• WEATHERPROOF SHELTERS
• PACKAGED STORMWATER MANHOLES
• PACKAGED METERING MANHOLES
• ROTATING SCUM SKIMMERS
• TITESEAL GATES
• FLAP VALVES
• CORROSION RESISTANT PIPE HANGERS
• ROOF AND EQUIPMENT HATCHES
• GAUGES
• FLOW MEASUREMENT FLUMES
• WEATHERPROOF SHELTERS
• PACKAGED STORMWATER MANHOLES
• PACKAGED METERING MANHOLES
• ROTATING SCUM SKIMMERS
• TITESEAL GATES
• FLAP VALVES
• CORROSION RESISTANT PIPE HANGERS
• ROOF AND EQUIPMENT HATCHES
• GAUGES
AA WWoorrlldd ooff SSoolluuttiioonnss iinn WWaasstteewwaatteerr CCoonnttrrooll..AA WWoorrlldd ooff SSoolluuttiioonnss iinn WWaasstteewwaatteerr CCoonnttrrooll..Plasti-Fab
®is the recognized leader in
corrosion resistant equipment for water and wastewater treatment and control, specializing in Reinforced Copolymer (FRP)
equipment for industry and infrastructure. Our equipment is resisting corrosion in abusive environments al l around the world. Contact one of our technical experts today to discuss how your specific requirements wil l be met with Plasti-Fab
®quality
products and custom services.
Plasti-Fab®is the recognized leader in
corrosion resistant equipment for water and wastewater treatment and control, specializing in Reinforced Copolymer (FRP)
equipment for industry and infrastructure. Our equipment is resisting corrosion in abusive environments al l around the world. Contact one of our technical experts today to discuss how your specific requirements wil l be met with Plasti-Fab
®quality
products and custom services.
HANDY FACTS TO REMEMBER
1 cu.ft. = 7.48 gals1 mgd = 694.4 gpm1 mgd = 1.55 cfs1 cfs = 449 gpm1 cfs = 0.646 mgd
SETTING FLUMESProper setting and size isnecessary for successfuloperation. Frequently theelevation of the crest of theflume is governed by themaximum allowable head.Where the crest of the flume ismore than 6" above thechannel bottom, a short slopingapproach to the inlet end ofthe flume should be provided.Flumes must always be set withthe inlet section level.
P L A S T I - F A B, I N C.P O B o x 1 0 0T u a l a t i n , O r e g o n9 7 0 6 2 - 0 1 0 0
p h o n e : 5 0 3 6 9 2 - 5 4 6 0f a x : 5 0 3 6 9 2 -114 5
e-mai l : sa les@plast i - fab.comweb: www.Plast i -Fab.com
P L A S T I - F A B, I N C.P O B o x 1 0 0T u a l a t i n , O r e g o n9 7 0 6 2 - 0 1 0 0
p h o n e : 5 0 3 6 9 2 - 5 4 6 0f a x : 5 0 3 6 9 2 -114 5
e-mai l : sa les@plast i - fab.comweb: www.Plast i -Fab.com
Bul. No. PF2.1 Copyright © 2001 by Plasti-Fab, Inc. (JD&C1698/STAC-2M) 5/01 Plasti-Fab® is a Registered Trademark of Plasti-Fab, Inc. Printed in the U.S.A.
