|
|
 
Surface Velocity Meters
Aquaflow Probe - Model 6900
 The Aquaflow Probe is an economical
lightweight water velocity instrument that is excellent for storm
water runoff studies, measuring flows in streams and partially filled
pipes. The Aquaflow Probe is a convenient flow meter but does not meet
USGS accuracy standards. The anodized aluminum telescoping handle is
available in lengths that extend from 3 ft. to 6 ft. and from 5 ft. to
15 ft. The key feature is unique, free rotating turbo-prop propeller
sensor protected inside a 2" diameter PVC housing. The housing may be
placed directly on the bottom of pipes or streams for measuring flows
down to 2" in depth. The unit may be extended up to 25 feet in length
for measuring sewers and from bridges using standard PVC pipe and
electrical extension cables. A 3 ft. mylar coated staff gage graduated
in hundredths and centimeters is attached directly to the lower
section of the probe for instantly measuring water depth and probe
position. The waterproof digital read-out , located on the top of the
handle, displays instantaneous velocity as well as true velocity
averaging. Two button keypad also allows readout of maximum velocity,
time, chronometer and totalizer. Easily replaced internal watch type
batteries power the unit for up to two years. Each Flow Probe is
shipped complete in a padded carrying case.
 
TOP
|
Item No. |
DESCRIPTION |
WEIGHT |
|
110-040 |
Aquaflow Probe 3 ft. to 6 ft. |
10 lbs. |
|
110-045 |
Aquaflow Probe 5 ft. to 15 ft. |
10 lbs. |
Surface velocity measurements are often the best
available measurements in extreme floods with dangerous velocities.
Often it is just not possible to safely or economically allow velocity
measurement equipment or personnel into the river. In these cases
there are two very good options:
The optical current meter is designed to measure
surface velocities in open channels without immersing equipment in the
stream. However, because it measures only surface velocity, the
optical meter is not considered a substitute for conventional
equipment in those situations where good measurements can be made by
standard techniques. It is a device that has extended the capability
of making discharge measurements to a range of situations under which
standard current-meter techniques cannot be used. Those situations
include flood velocities that are too high to measure by conventional
meter - for example, supercritical velocities in floodways - or the
presence of a debris load during flood periods that makes it hazardous
to immerse a current meter. Basically, the meter is a stroboscopic
device consisting of a low-power telescope, a single oscillating
mirror driven by a cam, a variable-speed battery-operated motor, and a
tachometer. The water surface is viewed from above through the meter,
while gradually changing the speed of the motor to bring about
synchronization of the angular velocity of the mirror and the surface
velocity of the water. Synchronization is achieved when the motion of
drift or disturbances on the water surface, as viewed through the
meter, is stopped. A reading of the tachometer and height of the meter
above the water surface are the only elements needed to compute the
surface velocity. A unique feature of the optical current meter is the
automatic correction that is made for variations in the direction of
the streamlines of flow. If the flow approaches the cross section at
an angle other than the perpendicular, and if the axis of the
oscillating mirror in the meter is parallel to the cross section, then
at the null point of observation, the water will appear to move
laterally across the field of view. The meter measures only the
velocity vector normal to the cross section and there is no need to
apply horizontal angle corrections.
|
Range of Velocities
that can be measured with optical current meter |
Observation Height
(D) Feet |
Maximum Velocity
Feet/Sec |
Minimum velocity for
+ 5% resolution Feet/Sec |
M/S |
| 6 (1.52 m) |
25 (7.62 m) |
1.6 |
0.49 |
| 10 93.05 m) |
50 (13.2 m) |
3.2 |
0.98 |
| 16 (4.57 m) |
75 (22.9 m) |
4.5 |
1.41 |
| 20 (6.1 m) |
100 (30.5 m) |
6.4 |
1.95 |
|
Item No. |
DESCRIPTION |
WEIGHT |
PRICE |
ORDER |
|
111-005 |
Ukiah Optical Current Meter |
30 lbs. |
Call |
Call |
top
This Microwave Water Surface Current Meter (MWSCM) is designed
for measuring the current speed easily in a river and other open
channels without contacting the water. It reduces the risk and
improves measurements in floods with extremely fast moving water.
It is a high tech current meter which can measure the current
speed safely and accurately in any flood condition. Current speed
is computed by the measured frequency difference, Doppler
Frequency, between the transmitting frequency from the antenna and
the frequency to the antenna after reflecting from the water
surface. The frequency signal is transmitted through an antenna
reflecting from the water surface. The Doppler frequency is
calculated by the comparison of the transmitted frequency signal
and the received frequency signal. The weak signal is amplified
and the speed of water surface is calculated through A/D
transformation and FFT. This provides:
Safe and simple measurement of current speed during floods
without damage to measurement instruments and danger to
personnel and multiple persons required during the measurement.
One person can measure speed easily without contacting water.
It can be used with 110 or 220 V or 12V DC battery and is easy
to move to the measurement site.
It can measure the current speed of a flood at night since the
microwave is not affected by the darkness.
It can save the measured data and transfer it to a personal
computer.
|
Item No. |
DESCRIPTION |
WEIGHT |
|
111-012 |
Microwave
Surface Current Meter |
45 lbs. |
top
|
