Thermo Scientific HB-S2000, Руководство пользователя

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Sarasota 2000 Ultrasonic Multipath
Flowmeter
Section 1 INTRODUCTION Page 1-1 Thermo Fisher Scientific
INTRODUCTION
1 INTRODUCTION
1.1 Applications
The Thermo Scientific Sarasota 2000 is a velocity x area open channel flowmeter which uses
the ultrasonic “time of flight”, also known as the “transit time” method.
Unlike traditional methods of open channel flow measurement which use weirs or flumes, the
transit time method creates no obstruction and assumes no relation between level and flow. It
will correctly determine flow throughout its designed range by measuring water velocity and
cross section area (see Section 1.2).
The method is tolerant of backwater effects caused by tides, downstream confluence or
blockages. Unlike a weir or flume it does not drown out at high flow conditions.
The method employs the transmission of ultrasonic “beams” which can be affected by factors
which impede or deflect them. For this reason the method should not be used in situations of:
•
Aerated water
•
Weed growth between the transducers (unless it is regularly cut)
•
High levels of suspended solids (greater than 2000 mg/l) *
•
Gradients of salinity (the actual value of salinity is, however, unimportant)
•
Gradients of temperature (the actual temperature is, however, unimportant)
* In relatively small channels (up to 5 metres) the method is more tolerant of suspended solids
and therefore is often used in sewage applications.
Though described as an open channel method, the flowmeter may be used in closed
conduits, including those which run full. In the latter case, the cross section area is defined by
the conduit geometry without the need to measure water level.
Suitable applications include water flow measurement of:
•
Rivers
•
Canals
•
Aqueducts
•
Irrigation conduits
•
Sewage discharges
•
Sewage works
•
Industrial discharges
•
Power generation
Note that although the flowmeter is most often used for open channels or part filled conduits,
it is often used for conduits which always run full. Under these circumstances it is not
necessary to have a depth input but steps need to be taken to ensure that the flowmeter
always takes the conduit as full. This is done via the encoder depth input. The conduit shape
must still be entered.