The water sampler should have sufficient strength, be flexible, convenient and reliable to use. The parts in contact with the water sample should be made of inert materials such as stainless steel and polytetrafluoroethylene. Before using the sampler, it should first be washed off with detergent to remove oil stains, then rinsed with tap water, and finally rinsed with 10% hydrochloric acid. After rinsing with tap water, it is ready for use.
1. Sampler type
(1) Surface sampler
For sampling related to water quality chemical analysis, open containers (such as buckets or bottles) can be immersed in the surface of the river for underwater collection.
(2) Sealed immersion device
The sealed immersion device is composed of a closed container filled with air (or inert gas), which is lowered to the required depth by a cable, and then the sealing device (such as a ring plug) is opened, with water replacing the air (or inert gas). This device is mainly suitable for sampling at specified depths.
(3) 3 Open pipe or cylinder device
This type of device is composed of tubes or cylinders, with folding pages or valves at both ends. When the device is lowered, the folding pages or valves open and water flows freely through; when it is lifted, they close. Such a device is suitable for sampling stagnant water or rivers with low flow rates.
(4) Suction device
It is usually regarded as a convenient method for collecting water samples. The suction system consists of a suction pipe immersed in water and a peristaltic pump.
(5) Automatic sampling device
The automatic device can continuously sample or collect a group of samples without human supervision. It is particularly suitable for situations where samples are mixed and water quality changes over time are studied.
2. According to the local actual situation, the following types of water quality samplers can be selected
Upright sampler. It is suitable for water sample collection in rivers, lakes and reservoirs with gentle water flow.
(2) Horizontal sampler. When used in combination with lead fish, it is suitable for collecting water samples from deep and fast-flowing rivers in mountainous areas.
(3) Acrylic water sampler. It is composed of a bucket body, two semi-circular upper covers with shafts and an active bottom plate, etc. It is mainly used for the collection of aquatic biological samples and is also suitable for the collection of water quality samples except for bacterial indicators and oil.
(4) Automatic sampler. Water samples can be drawn by using an electric sampling pump that starts and stops at regular intervals, or by using the pressure generated by the water level difference between the inlet surface and the surface surface for sampling, or by automatically sampling proportionally with changes in flow rate, etc. This type of sampler is suitable for collecting time or space mixed integration samples, but is not suitable for the determination of items such as oil content, pH, dissolved oxygen, electrical conductivity, and water temperature.