Niskin water sampler
Topic outline
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It consists of a water sampler made of polyvinyl chloride and a lid. The upper and lower lids are closed by the elasticity of a rubber tube or a metal spring (Figure 1). To remove the sample water from the water sampler, open the air vent at the top of the sampler and push in the water sampling port (PET cock) at the bottom of the sampler. The detailed structures of the upper and lower lids, the air vent, and the water sampling port (Pette cock) are shown in Figure 2. All of them are sealed with O-rings to prevent seawater from mixing with other seawater.
Fig. 1 Structure of Niskin water sampler
上蓋 Top Lid
採水筒 Water sampling bottle
ゴムチューブ(又はバネ) Rubber tube (or spring)
下蓋 Lower cover
空気孔(エアベント) Air vent
プッシュロッド Push rod
ワイヤクランプ Wire clamp
リリースブロック Release block
ナイロンテグス Nylon Tegs
採水口(ペットコック) Water sampling port (PET cock)
Fig. 2 Niskin water sampler Aperture mechanism
蓋 Lid
Oリング O-ring
空気孔 Air Hole
エアベントバルブ Air vent valve
空気 Air
採水口 Water sampling port
ガイドピン Guide pin
プルディスク Pull Disk
ペットコック Petcock
海水 Seawater
穴 Hole
ガイドピン Guide Pin
a) O-rings are fitted into the upper and lower openings of the water collection bottle, and the O-rings and the lid are sealed tightly together to maintain a tight seal. b) A screw-in valve (air vent valve) with a T-shaped hole is inserted into the air hole. When the valve is screwed in, the O-ring is crushed and the hole in the valve is blocked. Conversely, when the valve is loosened by twisting it, air enters the water sampling bottle. c) A T-shaped through-hole cock (petcock) is inserted into the water sampling port, and by sliding the cock back and forth, the water sampling port can be opened and closed. When the cock is pulled out, the hole is blocked by two O-rings. When the cock is pushed in, the hole is released and seawater flows out. The pull disk, which serves as a handle for sliding the cock, has a small hole in it, and this hole must be aligned with a metal rod (guide pin) protruding from the water sampling cylinder in order to push the cock in, making it difficult to accidentally release the cock.
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The water sampler with the lid open is attached to a wire rope, lowered to the desired depth, and then the lid is closed to collect the water ( Fig. 3 ).
Fig. 3 Niskin water sampler fixed to wire rope
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Setting up the water sampler
Before attaching the water sampler to the wire rope, leave the lid of the sampler open ( Fig. 4 and Fig. 5 ). Also, make sure that the water sampling port and air hole are closed.
Fig. 4 How to open the lid and set it on the trigger
上蓋 Upper Lid
下蓋 Lower Lid
プッシュロッド Push Rod
トリガーピン Trigger pin
スナップフック Snap hook
a) Open the top lid. Pass the tegus through the inside of the handle and secure the end of the tegus to the trigger pin. The trigger pin slides with the up-and-down movement of the push rod. b) Open the lower lid. Hook the snap hook at the end of the tegus onto the tegus on the upper lid. c) Set is complete.
Fig. 5 Notes on opening the lid
If a strong impact is applied when opening the lid, the edge of the water sampler may be chipped and the seal of the water sampler may be compromised. If the rubber (or spring) is pulled in the direction of extension (upward for the top lid) and then knocked down, the lid can be opened without applying impact.
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Attachment to the wire rope
Attach the water sampler to the wire rope, with the weight suspended and taut, using the fixture (clamp) provided on the back (Fig. 6).
Fig. 6 Fixing method to wire rope
ワイヤーロープ Wire Rope
蝶ナット Wing Nut
固定ブロック Fixing Block
クランプボルト Clamping Bolt
Fix the water sampler by fitting the wire rope into the groove of the clamp bolt and tightening the wing nut. Fix in two places in this order: upper part, then lower part.
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