Title: Flow Meter
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- ???? ??? ????????? SCFM ? SCCM
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(Rotameter) - ????? ???? ?? ?????? ????? ???? ?? ????
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6????? ??? ???? ??????? ???? ( ???????) (PD)
- ?????? ???? ?? ???? ??? ????? ??? ???? (Positive
Displacement) - ?? ?????? ?? ??? ???? ???? ??? ???
- ?? ??? ???? 1 ???? ??? ?????? ???? ?? ????
- ?????? ???? ?? ???? ????? ???? ??? ?? ???? ??
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9??? ??? ?????? Nutating Disk
- ?????? ??? ?????? ???? ?? (?????)
- ???? ???? ????? ???? ?? ?? ??? ????? ?? ?? ????
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??? - ????? ????? ?? ???? ??? ?? ???????? ????? ?
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10(No Transcript)
11??? ??? ?? ??? ??? ????? Oval Flow meterLobed
Impeller Flow meter
- ???? ?????? ???? ??? ??? ?? ? ??????
- ??? ?? ? ????? ?? ??? ???????? ???
- ???? ????? ?? ???? ?? ??? ????? ???? ? ?? ???
???? ?? ????? ????? ????? ?? ??? - ??? ?? ??? ?? ???? ???? ? ????? ????? ???
??????? ???? ?????? (??????) - ?????? ??????? ??? ??????? ?? ? ????? ???? ????
??? ?? ?? ???? 0.1 ? ???? ?? ???
12??? ??? ??? ?? Vane type positive displacement
flow meter
- ???? ?? ???? ????
- ??? ?? ?? 0.5 ????
13????? ?????? ????? ?? ?????? ???????Obstruction
Flow meters OR Differential pressure flow meters
- ???? ????? ?????? ??? ??? ???? ???? ???? ?????
????? ???? ????? ????? ?? ???
?? ???? ????? ?????? ? ??????? ?? ???? ??? ?????
?? ?????? ????
????? ???????
???? ?? ?????? ???? ??? ???? ?? ?? ???? ?? ????
??? ???? ?? ?????? ????
K ????? ?? ???? ????? ?????? ????? Constant of
flow obstruction device
????? ?????? ??? ????? ????? ???? ?? ??? ?????
??? Cd ?? ??? ????? ( ?????? ?? ???? ) ? ?????
?????? ? ??? ??????? ????? ????
14?????? ??????
Orifice Plate1- ????? ????? ??? ??? ???? ?
????? ??? ?? ??? ???? ???? ????
2- ?????? Venturi Tube
- ???? ??? ??? 0.98 ??? 0.95
- ??? ???? ? ??? ???? ????? ??
- ???? ???? ? ???? ?? ???? ????
- ???? ???? ?? ???? ????
153- ???? ?? ?????? Nozzle
????? ?????? ?????? ??? ??? ???? ????? ????? ???
??? ???? ? ????? ???? ??? ?? ???? ?? ???
164- ??????? ?? ???? ??? ?? Segmental Wedge
5- ??????? ?? ????? ?????? ??? V-Cone
176- ??????? ?? ?????? Elbow
?? ???? ?????? ???? ?? ???? ? ???? ?????? ?? ???
????? ???? ?? ???? ?????? ???? ????? ??? ???? ??
????? ???? ???
18?????? ????? ?? ????? ??????
- ????? ???? ?? ????? ?? ?? ?? ??? ????? ???? ????
???? ?????? ?? ???? ? ??? ??? - ?? ????? ??? ????? ???? ? ????? ??? ?????? ????
?? ???? ??? ?? ????? ???? - ?????? ????? ????? ??? ????? ???? ? ?????
????????? - ????? ???? ????? ???? ? ???? ???? ????? ?????????
- ?? ????? ???? ???? ?? ???? ????? ??? ????
- ????? ???? ????? ????????? ? ???? ???? ????? ????
- ?? ??????? ?? ??? ? ?? ??? ????
19??????? Rotameter OR Variable Area Flowmeters
- ?????????? ??? ??? ?? ??? ???? ?????
- ????? ?? ????? ???? ???? ?? ?? ??? ????? ????
????? - ???? ?? ????? ????? ?? ???? ?? ?? ???? ????
- ??? ?? ???? ?? ????? ?? ??? ??
- ????? ?????? ? ?????? Buoyancy
- ?? ????? ??? ????? ???
- ??? ?????? 1-5 ????
- ???? ???? ?? ??? ???? ??? ???
20???? ????? ???????
- ?? ?????? ???? ??? ???? ?? ????? ????? ????? ????
?? ???
?f ? ?b ????? ???? ? ????? ? Vb ??? ?????
?? ??? ???? ??? ?? ???? ????? ???? ???? ????? ?
?? ???? ????
Cd ???? ????? ?????. ????? ?? ??? ??????? ?
???? ????? ?? ?? ?? ???? ???? ???? ????
D ??? ???? ?? ????? d ?????? ??? ????? y ?????
????? ????? ?? ????? a ???? ??????? ????
21Spring and Piston Flow Meters
- Piston-type flowmeters use an annular orifice
formed by a piston and a tapered cone. The piston
is held in place at the base of the cone (in the
"no flow position") by a calibrated spring. Their
simplicity of design and the ease with which they
can be equipped to transmit electrical signals
has made them an economical alternative to
rotameters for flowrate indication and control.
22????? ??? ??? ????? ??? ????
23??? ??? ????? ?? ??? ???? Target Flow meter
- ??????? ?? ???? ???? ?? ??? ?? ?? ?????
- ???? ???? ?????? ?? ????? ???? ?? ??? ???
- ????? ??? ???? ?????? ??? ?????? ???? ?? ???
- ??? ???? 0.5 ????
- ?????? ????? 0.1 ????
24(No Transcript)
25??? ??? ??????? Turbine Flow meter
- ????? ?? ????? ?? ???? ?? ?? ?? ???? ?? ??????
??? - ???? ???? ?????? ?????? ?? ???? ???? ???
- ?? ????? ????? ??? ?????? ?? ???? ???? ??? ????
?? ??? - ??? ???? 1 ????
- ????? ?????? ???? ? ??? ?? 100 centistokes
26f ?????? ???? K ???? ????? ?????? ????? ?? ??? ?
???? ????????? ????
27??? ??? ???????? Electromagnetic Flow meter
- ???? ???? ????? ?? ???? ????? ???????? ???? ?????
????? ?? ???? (????? ??????) - ???? ?????? ?? ???????? ?? ?? ????? ??????
- ????????? ???????? ?? ????
- ???? ?????? ?? ???????? ???? ?? ???????? ????
- ????????? ???? ?? ???? ?? ?????? ?? ???
EBLv
28(No Transcript)
29??? ??? (??????) ??? ??? Hot Wire Anemometer
- ????? ?????? ???? ??? ????
- ?????? ???? ???? ?? ?? ??????? ???????
- ???? ???
- ??? ??? ???? ?? ???? ?????? ?? ???? ???? ????
?????? ?? ???? ???? ??? ?? ??? - q(abv0.5)(Tw-T?) (King)
- q i2 Rwi2R ref (1?(Tw-Tref))
- ?? ?????? ???? i ? RW?? ???? ????????? ??? ????
???? ?? ???? ????
a ? b ???? ??? ?????? q ???? ?????? ???? v
???? ???? Tw ???? ??? T ? ???? ???? ?? ?????
????
30??? ??? ??? ??? (?????.....)
- ????? (????????) ???? ? ???? ????? ?????
- ??????? ???? ????? ?????? ?? ???? ???? ???
??? ???? ???Aw
?? ?????? ???? ???? ???? Tf ???? ???? ???? ?????
?? ???? ??? ????? ???
31- ???? ????? ???? ?????? ?????
- ??????? ????? ?????? ?? ???? ???? ???
- For a hot-wire anemometer powered by an
adjustable current to maintain a constant
temperature, Tw and Rw are constants. The fluid
velocity is a function of input current and flow
temperature - where a, b, and c are coefficients obtained from
calibration (c 0.5). - The temperature of the flow Tf can be measured.
The fluid velocity is then reduced to a function
of input current only
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34??? ??? ????? ?? ???? (?????? ????)Pressure Probe
- ???? ?????? ???? ????? ??? ????? ?????? ?????
????? - ???? ???
- ???? ?? ??????? ? ????? ??? ? ???
- ?? ??? ?????? ?? ?? ???? ?? ???? ???? ? ?? ?????
?? ???? ?? ???? ???? - ?????? ???? ???? ???? Pitot Tube ?????? ?? ???
35?????? ?????? ???? ?? ???? ?? ?? ?????? ???? ????
???? V1 ?? ????? ??? ??? ???
?????? ???? ?? ????
??? ???? ???????? ?? ?? ?? ???? ????? ???
?????? ???? ????
36Pitot Tube (Cont)
- ?????
- ?????? ?? ?? ????? ?????
- ?????
- ???? ??? ?? ??? ???? ???? ?? ??? ?????
- ?? ??? ??? ???? ???? ?? ???? ?????
- ???? ???? ????? ??? ???? ?? ?? ??????? ???
- ?? ?????? ????? ???? ??????? ????
37?????? ???? ??? ?? ????? ?? ???
- ??????? ?? ??? ?????
- ?????? ???? Parshall flume
- ?????? ???? ????
- ?? 0.01 3000 cfs
- ?????? ???? ?? ??? ???? ??
- ?????? ???? ???? ???? ?? ?? ?????? ???? ???
- ???? ???? ?? ???? ????
- ???? ?? ?? ?? ?????
- ???? ?? ??? ???? ?? ????
- ??????? ?? ???? ???? ????? ??? Ha Q
- ??? Hb ???? ?? 0.7 Ha ???? ???? ??? ? ??? ??
??? 1 ?? 8 ??? - Q4WHa1.522W0.026
38(No Transcript)
39??????? Weirs
- ????? ?? ????? ?? ?? ???? ????? ?? ??? ???? ??
???? - ??? ???? ???? ?? ????
Q weir discharge (m3/s) B weir base width
(m) H head above weir crest excluding
velocity head (m) Cscw 1.81 0.22 (H /Hc )
40????? Orifice
- V (2gh)0.5
- QCA (2gh)0.5
- C ????? ?? ??? ????? ?? ???? ????? ????
41?????? ???? ????? ???? ???
- ?? ???? ????? ???? ?? ?? ??????
- ?? ???? ?????? ???? ??? ???? ?? ???? ??? ????
????? - ?????? ???? ???? ? ????? ???? ?? ?????? ????
42The mass flow meter uses the science of
particle acceleration and its resultant forces
to measure flow rate and total weight at
accuracies of /- 0.5. It consists of a
partitioned measuring wheel, mounted on a drive
shaft inside a central dust tight housing. The
drive shaft is driven by an electric
motor mounted outside the housing. Material
enters the unit through an off-center inlet and
discharges through a center outlet below the
measuring wheel.
In operation, the measuring wheel rotates at a
constant speed. Material entering the unit flows
into the top of the measuring wheel and is
deflected outward in a radial direction creating
a "Coriolis force". This force is detected as a
change in torque which is detected by a strain
gauge load cell. Best of all, unlike other flow
meters the performance is not affected by
material density, friction or in-feed drop
height.
43DEFLECTION CHUTE MEASURING
- The deflection chute measuring system for Solids
Flow Meter is also based on reactive force but a
curved guide chute is used in place of an impact
plate. As a result, impact or shock is replaced
by radial acceleration and chute deflection that
a load cell detects. This signal is then
electronically processed to produce flow rate and
total weight values at accuracies generally
better than /- 2 and with repeatability of
0.5. - Ideal for relatively high flow rates of
free-flowing or pulverized materials. - 30 to 600 tons per hour.
- Material temperatures from 0 to 500 F (260 C).
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