Current Meters And Open Channel Meters
Current Meters and Open Channel Meters have been a speciality of Valeport’s since the company was first formed in 1969. The company started making instruments for measuring the speed of the water in London’s River Thames, since then our product range has grown, but our expertise in current flow measurement remains.
Whichever type of instrument your require, whether it’s the traditional impeller mechanism, or the high accuracy electromagnetic type, Valeport can offer a solution. Configurations are available that are suitable for use in a wide variety of applications, from hand held measurements in the smallest streams, through modelling experiments in the laboratory, to self-contained instruments for navigable rivers, estuaries, ROVs and the deep ocean.
Our impeller instruments use the simple premise of measuring the speed of rotation of a helix in the water. PTFE bearings eliminate the need for specialised lubricants and the magnetic contact closure minimises the moving parts in the system – this also allows the sensor itself to be remote from the measuring electronics (ideal in deep water applications).
The electromagnetic sensors use the Faraday Principle to measure the water speed. As a conductor (water) moves through an electromagnetic field (generated by the sensor), it generates a voltage that is measured by the sensor electrodes. Modern day signal conditioning electronics and filtering techniques allow highly accurate measurements to be made, and there is a choice of sensor shapes and sizes to suit the application. The solid state sensors and standard titanium / polyurethane construction provide excellent corrosion resistance, and depth ratings up to 5000m.
Model 106 Lightweight Current Meter
A low cost, lightweight alternative to larger flow meters, ideal for use in applications where the superior durability and depth rating of Valeport’s larger meters is not necessary. Utilising the standard Valeport 125mm diameter impeller, the Model 106 features speed and direction parameters as standard, with further options of temperature and depth.
Data (logged or real time) is compatible with Valeport’s DataLog™ software. The instrument is manufactured from titanium and polymers, giving excellent resistance to corrosion, whilst maintaining a small size and low weight. These features make the Model 106 the ideal instrument for coastal and estuarine applications, and other light duty survey work.
The Model 106 Current Meter is a light weight, cost effective impeller current meter, designed for real time current measurement or short to medium term autonomous deployments. Titanium construction ensures durability, and the optional temperature and pressure sensors increase the versatility of the instrument. Ideal for use in rivers and coastal applications, or from small boats, the Model 106 is simple to use with either the Windows based PC software supplied, or an optional dedicated display unit.
Sensors
| Speed | |
| Type : | High Impact Styrene Impeller |
| Size : | 125mm diameter by 270mm pitch |
| Range : | 0.03 to 5m/s |
| Accuracy : | ±1.5% of reading above 0.15m/s ±0.004m/s below 0.15m/s |
| Direction | |
| Type : | Flux gate compass |
| Range : | 0 to 360° |
| Accuracy : | ± 2.5° |
| Resolution : | 0.5° |
| Temperature | |
| Type : | Thermistor |
| Range : | -5 to 35°C |
| Accuracy : | ± 0.2°C |
| Resolution : | 0.01°C |
| Pressure | |
| Type : | Strain Gauge Transducer |
| Range : | 50, 100, 200 or 500 dBar |
| Accuracy : | ± 0.2% Range. |
| Resolution : | 0.025% Range |
Data Acquisition
The current meter works on a basic 1 second cycle, during which the impeller counts are taken and a single compass heading reading is made. From this, East and North velocity vectors are calculated, which are then summed over the averaging period. The additional parameters of temperature and pressure (if fitted) are sampled once every sample period, and averaged over the averaging period.
Data Recovery
Direct to PC via communications port. Maximum RS232 data rate of 19200 baud.
Switching On/Off
The meters are switched on and off through software control, either by the DataLog™ software or by using the Model 8008 CDU. However, for autonomous, self-recording operation the 106 is supplied with a SubConn switch cap that fits in place of a direct cable connection.
Display Unit
The Model 106 may be used with a dedicated display unit for real time operations allowing instrument setup and data display.
| Size : | 244 x 193 x 94mm, 2kg |
| Protection : | IP67 (10 secs @ 0.3m) |
Memory
512 Kbyte Solid State Memory. Each parameter record uses 2 bytes. As an example, this gives a duration of over 1 week with full parameter sampling every 10 seconds, or 220 days with sampling every 5 minutes.
| Power | |
| Internal : | 1 x D cell. 1.5v alkaline cell gives approximately 30 days at 10 second sample rate, or 56 days at 5 minute sample rate. 3.6v Lithium cell gives approximately 90 days at 10 second sample rate, or 180 days at 5 minute sample rate. |
| External : | For external supply, 12-20v DC is required. Power can also be taken from the Model 8008 CDU. |
Communications
Fitted with Subconn MCBH10F (Brass)
RS232 to PC over cable lengths up to 200m.
Digital Current Loop to Model 8008 CDU, or to PC over longer
cable lengths (requires additional adaptor).
Physical
| Instrument | |
| Material : | Titanium, acetal and ABS plastic |
| Size : | 640mm x 50mm Ø tail 133mm wide x 270mm high |
| Weight : | 3kg (air), 2kg (water) |
| Depth Rating : | 500m |
| Shipping | |
| Model 106 Size : | 84 x 42 x 39cm |
| Model 106 Weight : | 17 kg |
| 50m Cable Size : | 42 x 33 x 49cm |
| 50m Cable Weight : | 11kg |
Software
System is supplied with DataLog x2Windows based PC software, for instrument setup, data extraction and display of tabular and graphical data plots. DataLog x2 is license free.
Ordering
| 0106001SC | Model 106 Self-Recording/Direct Reading Fitted with: ? Speed and Direction sensors Supplied with: – Communications lead (3m Y lead) – Switch Cap – Software – Operating manual, Tool kit and transit case. |
| 0106003SC | As 0106001SC plus Temperature option |
| 0106004SCXX | As 0106001SC plus Depth option |
| 0106005SCXX | As 0106001SC plus Temperature & Depth |
| Note : | (XX denotes pressure transducer range) |
| 0105005SC | Control Display Unit set, comprising deck lead and Model 8008 CDU. |
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