Multiple Plankton Sampler

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Smart Sampling at its best – with the improved MultiNet generation of the Multiple Plankton Sampler, the world’s leading sampling system for horizontal, oblique and vertical collections in successive water layers. The MultiNet can be delivered in 4 sizes (apertures): Mini (0.125 m²), Midi (0.25 m²), Maxi (0.5 m²) and Mammoth (1 m²). Depending on the model 5 or 9 net bags are attached to the stainless steel frame with strong canvas part by means of zip fasteners. The net bags are opened and closed by means of levers which are triggered by a battery powered Motor Unit. The commands for actuation of the net bags are given via single or multi-conductor cable between the Underwater Unit and the included Deck Command Unit. A wide selection of mesh sizes for the net bags is available to meet the requirements of all standard and non-standard applications. For common horizontal collections a mesh size of 300 microns is recommended (mesh sizes from 100 to 780 microns available), for vertical collections mesh sizes from 55 to 780 microns are applicable. For mesh sizes below 100 microns it is recommended to use an enhanced net bag (for example a double-layered net bag: one with 55 microns plus one with 300 microns )
An integrated Pressure Sensor (measuring range according to customers’ requirements) allows continuous supervision of the current operating depth. Depth values and all relevant system data are shown on the LCD-display of the Deck Command Unit. Two Electronic Flow Meters with automatic angle compensation are mounted to the Underwater Unit: one inside the frame for the determination of the amount of water passing through the open nets, one outside the opening for the determination of clogging effects. For horizontal collections a V-Fin Depth Depressor is attached to the MultiNet. To carry out vertical collections, a stainless steel support is securely attached to the net buckets and enables a quick lowering to depth.
OPERATION
In its initial position the MultiNet is brought to water with all net bags closed and the water flowing freely through the frame. The instrument can be lowered with high speed to the greatest desired depth. There the first net bag is opened by push-button control from the Deck Command Unit. At the end of the horizontal collection resp. after passing the intended depth interval in case of vertical operation, the first net bag is closed by a second command. The second net is opened simultaneously. This procedure is repeated for the remaining net bags and the Deck Command Unit indicates the number of the currently active net bag. During operations of Mini and Midi versions the last net (no. 5) remains open to collect plankton from the smallest desired depth up to the water surface. Using the Maxi and Mammoth versions the last net (no. 9) can be closed before reaching the water surface.
OFFLINE USE
In case that a conducting cable is not available on board, the required sampling depth can be pre-programmed via personal computer. The activation of the net bags is then carried out automatically according to the pre-selected depth intervals. All measuring data are stored inside the internal data memory of 16 MByte during the operation and can be read out by a PC when the MultiNet is back on board.

  • Technical Data
  • Multiple Plankton Sampler

  • Accessories
  • Ordering Information
Underwater Unit Type Mini
No. 438 120
Type Midi
No. 438 130
Type Maxi
No. 438 140
Type Mammoth
No. 438 180
Dimensions (w x l x h) 65 cm x 90 cm x 80 cm 80 cm x 90 cm x 95 cm 120 cm x 110 cm x 135 cm 150 cm x 120 cm x 160 cm
Net Opening 35.5 cm x 35.5 cm
= 0.125 m²
50 cm x 50 cm
= 0.25 m²
71 cm x 71 cm
= 0.5 m²
100 cm x 100 cm
= 1 m²
Net Bags 5 pcs., length: 160 cm 5 pcs., length: 250 cm 9 pcs., length: 365 cm 9 pcs., length: 550 cm
Standard Mesh Size 300 µm 300 µm 300 µm 300 µm
Plastic Net Buckets 5 pcs., 11 cm dia. 5 pcs., 11 cm dia. 9 pcs., 11 cm dia. 9 pcs., 11 cm dia.
Soft Net Buckets 5 pcs., 11 cm dia. 5 pcs., 11 cm dia. 9 pcs., 11 cm dia. 9 pcs., 11 cm dia.
Overall length ready for operation (from bridle to net bucket 470 cm 560 cm 800 cm 1000 cm
Weights
Net Frame approx. 75 kg approx. 100 kg approx. 260 kg approx. 390 kg
Stainless Steel Support approx. 30 kg approx. 50 kg approx. 70 kg approx. 100 kg
V-Fin Depth Depressor approx. 22 kg approx. 22 kg approx. 70 kg approx. 70 kg
Materials
Net Frame Stainless Steel Stainless Steel Stainless Steel Stainless Steel
Motor Unit and Battery Housing Titanium Titanium Titanium Titanium
Net Bags MOnyl MOnyl MOnyl MOnyl
Net Buckets PVC/Canvas PVC/Canvas PVC/Canvas PVC/Canvas
V-Fin Depth Depressor Aluminium, lead-weighted Aluminium, 
lead-weighted
Aluminium, 
lead-weighted
Aluminium, 
lead-weighted
Operational Depth Standard 3000 metres Standard 3000 metres Standard 3000 metres Standard 3000 metres
Pressure Sensor Standard 3000.0 dbar
±0.1% f.s.
(other ranges on request)
Standard 3000.0 dbar
±0.1% f.s.
(other ranges on request)
Standard 3000.0 dbar
±0.1% f.s.
(other ranges on request)
Standard 3000.0 dbar
±0.1% f.s.
(other ranges on request)
Offline-Set Data memory: 16 MB Data memory: 16 MB Data memory: 16 MB Data memory: 16 MB
Electronic Flow Meter 2 pcs., 0.0 … 9.9 m/s 2 pcs., 0.0 … 9.9 m/s 2 pcs., 0.0 … 9.9 m/s 2 pcs., 0.0 … 9.9 m/s
Connection Plug SUBCONN IL 2 M SUBCONN IL 2 M SUBCONN IL 2 M SUBCONN IL 2 M
Cable Counter Plug SUBCONN IL 2 F SUBCONN IL 2 F SUBCONN IL 2 F SUBCONN IL 2 F
Cable Connection Electro-mechanical single- or multi-conductor cable, one pole can be in contact with sea water
Towing Cables Type Mini
No. 438 120
Type Midi
No. 438 130
Type Maxi
No. 438 140
Type Mammoth
No. 438 180
Breaking load for shallow water applications
(up to 500 m)
approx. 1500 kg approx. 2000 kg approx. 4000 kg approx. 8000 kg
For deep sea applications (from 500 m up to 3000 m) approx. 5000 kg approx. 8000 kg approx. 12000 kg approx. 18000 kg
Max. Cable
Resistance (go-and-return line)
1000 Ohms 1000 Ohms 1000 Ohms 1000 Ohms
Deck Command Unit: Metal housing for use in 19″ rack or as table housing, not for use on deck; push-button control for net changing; indication of net number, pressure, battery status, … LCD-display with LED backlight; Interface for Personal Computer (RS 232)
Power Supply
Underwater Unit 3 Lithium Batteries DL 123 A/3V, sufficient for approx. 100 hours operation
Deck Command Unit 85 – 260 VAC 85 – 260 VAC 85 – 260 VAC 85 – 260 VAC
Towing Speed Recommended for nets with 300 microns standard mesh size
Horizontal Collections max. 4 knots max. 4 knots max. 4 knots max. 4 knots
Vertical Collections max. 1 m per sec. max. 1 m per sec. max. 1 m per sec. max. 1 m per sec.
CT-Set The CT-Set consists of one conductivity sensor, one temperature sensor and an additional electronics board which are completely integrated into the Motor Unit of the MultiNet. From the CTD data the system computes salinity, density and sound velocity according to UNESCO formulas
Pitch and Roll Sensor The Pitch and Roll Sensor has been developed for measurements of pitch angle and roll angle of the Underwater Unit of the MultiNet. It allows continuous supervision of the current orientation during horizontal operations.
Products  
438 120 MultiNet Type Mini, 0.125 m²
438 130 MultiNet Type Midi, 0.25 m²
438 140 MultiNet Type Maxi, 0.5 m²
438 180 MultiNet Type Mammoth, 1 m²
Accessories  
450 500 CT-Set for MultiNet
Conductivity sensor: 0 … 65 ± 0.01 mS/cm,
Temperature sensor: -2 … +32 ± 0.005°C
Data rate: 1 Hz (1 data set per second)
438 161 Pitch and Roll Sensor
Channel Pitch: + 60° … – 60° ± 1° related to the horizontal
Channel Roll: + 60° … – 60° ± 1° related to the horizontal
Spare Parts  
438 123 Spare Net Part (one single net) for MultiNet Type Mini
438 127 Spare Canvas Part for MultiNet Type Mini
438 133 Spare Net Part (one single net) for MultiNet Type Midi
438 137 Spare Canvas Part for MultiNet Type Midi
438 143 Spare Net Part (one single net) for MultiNet Type Maxi
438 147 Spare Canvas Part for MultiNet Type Maxi
438 183 Spare Net Part (one single net) for MultiNet Type Mammoth
438 187 Spare Canvas Part for MultiNet Type Mammoth
438 150 Spare Plastic Net Bucket, consisting of:
a) Fixing Ring with over centre fasteners for attaching to the end of a net
b) PVC-Net Bucket with side window, covered with sieve gauze
438 930 Soft Net Bucket with bolt rope
438 935 Mounting ring for Soft Net Bucket
438 116-in Electronic Flow Meter (inner) for MultiNet
438 116-out Electronic Flow Meter (outer) for MultiNet

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