Dissolved oxygen and temperature combined sensor

Abstract

The invention discloses a dissolved oxygen and temperature combined sensor, comprising a dissolved oxygen and temperature signal unit, an oxygen permeation membrane and electrolyte unit and a shield unit. The signal unit is composed of a signal piece, a fixed positive pole embedded into one end of the signal piece, a temperature module arranged in the positive pole, and a replaceable negative polewound on the outside of the signal piece. The positive and negative poles are separately connected with an electric wire, and the temperature module is connected with the two electric wires. The oxygen permeation membrane and electrolyte unit is a hollow pipe with a full open upper end and a partially open lower end; internal threads are arranged in both the upper and lower open ends, the internal thread at the upper end is connected with an external thread of the signal unit, the internal thread at the lower end is connected with a pressing block with an external thread, an oxygen permeationmembrane and a sealing ring are arranged between the pressing block and the pipe wall; electrolyte is filled into a closed space in the hollow pipe. The shield unit is arranged on the membrane and the electrolyte unit in a sleeving manner. According to the dissolved oxygen and temperature combined sensor provided by the invention, the service life and the maintenance period of the dissolved oxygen sensor can be greatly prolonged, the response time of reaching the stable measured value is reduced, and the maintenance process is simpler.

Description

technical field [0001] The invention belongs to the field of water quality detection and water treatment, and in particular relates to a two-in-one sensor for dissolved oxygen and temperature. Background technique [0002] Dissolved oxygen is defined as molecular oxygen in the air dissolved in water called dissolved oxygen (DO), which is expressed in milligrams of oxygen per liter of water, and the unit is mg / L. Dissolved oxygen usually has two sources: one source is when the dissolved oxygen in the water is less than the dissolved oxygen in the atmosphere (that is, when it is not saturated), the oxygen in the atmosphere infiltrates into the water body; the other source is the oxygen released by plants in the water through photosynthesis . Therefore, the dissolved oxygen in the water will be continuously replenished due to the incorporation of oxygen in the air and the photosynthesis of green aquatic plants. However, when the water body is polluted by organic matter, or th...

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Problems solved by technology

[0004] 1. The electrolyte of the existing polarographic dissolved oxygen sensor with film coating and external power supply has a short service life and must be replaced frequently: this type of sensor needs to consume electrolyte during measurement, resulting in less and less electrolyte, resulting in short maintenance cycles

[0005] 2. Polarographic dissolved oxygen sensors with film-coated primary batteries have a short service life: this type of sensor does not need to consume electrolyte for measurement, but will continue to oxidize and consume negative (anode) metal

The negative electrode (anode) of the existing film-coated primary battery polarographic dissolved oxygen sensor cannot be replaced, resulting in a short service life of the sensor

[0006] 3. The temperature response of the two existing dissolved oxygen sensors is slow, resulting in a long response time for the measured value of dissolved oxygen to reach a stable value: the installation position of the temperature sensing module for measuring temperature and temperature compensation is not optimal, that is, there is no recent degree The temperature module is close to the water body to be measured, resulting in slow heat transfer of the temperature module or being covered by foreign objects, which affects the measured value of dissolved oxygen and has a long response time

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