Method for along-the-cable underwater profile measurement

Abstract

A method includes: a guide cable and an observation platform is provided, a profiler is mounted, and a trigger gear is set at the bottom of the guide cable; a weight drop-off gear is set at the top of the guide cable, when the observation platform is located at the top of the guide cable, one weight is released by the weight drop-off gear onto the observation platform so that the observation platform descends along the guide cable owing to additional gravity, and when the observation platform descends to the given position of the trigger gear at the bottom of the guide cable, the release gear releases the weight on the observation platform so that the observation platform returns by its own buoyancy to the top along the guide cable; another weight is subsequently released by the weight drop-off gear so that the observation platform repeats the foregoing reciprocating motion.

Description

TECHNICAL FIELD[0001]The present invention relates to the field of the water environment monitoring technologies and more specifically to a new method for along-the-cable underwater profile measurement.BACKGROUND[0002]Presently, there are two basic methods for along-the-cable underwater profile measurement.[0003]A first method is that the mobile observation platform ascends or descends under the water through controlling the buoyancy and gravity of the observation platform. The method has been applied in most of the basic schemes for the current formed equipment, for instance, a mobile sealed compartment is connected with an outer oil sac which is connected with an inner oil sac via a solenoid valve and an oil pump is pressurized by an electronic circuit controlled air pump in the compartment to discharge the oil from the inner oil sac to the outer oil sac so as to increase the volume of the drain water from the platform, thus increasing the buoyancy of the platform to make the plat...

AI Technical Summary

Benefits of technology

This approach enables continuous, long-term observation of water profiles at any depth without battery limitations, with adjustable descending speed and measurement frequency, simplifying the platform design and extending measurement capabilities beyond previous limitations.

Problems solved by technology

Although the method can easily control, through its circuit, the slight buoyancy of the platform and change the buoyancy without additional electric power consumption during platform motion, it has the following challenges:1. The mechanical control part in the compartment is complex and requires a precision air pump, oil pump, solenoid valve and accurate measurements with related sensors;2. All power is sourced from batteries which have a huge influence on the gravity of the sealed compartment, the design of compartment body is closely related to the quantity of batteries, their service life directly determines the overall design, that is, the battery may affect the whole method;3. The method, with limited working water depth, is mostly applied to the measurements for the water depth less than or within 2000 m at present, and for the water depth more than 2000 m, the power consumption of the batteries required for pumping the oil to the outer oil sac because the increase of water depth cannot keep balance with the battery efficiency, the overall design of the compartment cannot satisfy further power consumption, thus resulting in failure to complete further measurements.

The method has the advantages including simple mechanical design part, minor influence of the water depth and simplicity in electronic control but has several difficulties:1. Every step of platform motion will consume electricity, which constitute a huge challenge to the batteries, and like the first method, there are corresponding requirements on the design of the electronic compartment, the times of the working profiling determines the quantity of the batteries, thus determining the design size of the electronics compartment.2. The platform, with limited motion speed, requires the motor for every meter of motion in the process of ascending and descending, and huge electricity consumption is required with the increase of the platform motion speed, which constitute a huge challenge to the reliability of the inner motor and outer roller.

It can be seen that the power energy storage mechanism (battery and motor) and measurement mechanism are provided on one platform for the above-mentioned two measurement methods so that there is a problem that the energy for controlling the platform motion is restricted by the battery, thus exerting a decisive influence on the overall design.

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