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CN-121990114-A - Easily-laid thermal salt profile observation system and laying method thereof

CN121990114ACN 121990114 ACN121990114 ACN 121990114ACN-121990114-A

Abstract

The invention discloses an easy-to-lay warm salt profile observation system and a laying method thereof. The device is constrained into a compact integrated structure before being put in, self-driven switching from a constrained state to an observed state is realized based on time sequence dissolution of a controllable degradable material after water is put in, and the water-soluble bracket, the binding band and the buckle are preferably selected from a PVA/CMC system, so that the device has both dry and wet state strength and predictable dissolution rate. The cable adopts piecewise linear constraint and sets up progressively decreasing locking force from bottom to top, realizes that the bottom section releases the orderly expansion of cable earlier, upper segment later release cable, reduces initial disturbance and promotes and expand the success rate. The arc surface lifting and the anti-skid limiting are used for reducing the flow around interference, and the arc surface lifting and the anti-skid limiting are matched with the flexible connection of the shallow draft floating body, the small floating ball arranged along the cable and the bottom counterweight, so that the chain shape tends to be vertical after being unfolded, and the method is suitable for continuous observation of the warm salt profile in the depth range of about 5-100 m.

Inventors

  • QIU ZHONGFENG
  • MA CHANGLAN
  • Shi Xuanshuo
  • DING MENGJIAO
  • LIU YONGXI

Assignees

  • 南京信息工程大学

Dates

Publication Date
20260508
Application Date
20260401

Claims (10)

  1. 1. The system is characterized by comprising an overwater floating body unit, an underwater observation unit, a connecting cable and a water-soluble auxiliary device, wherein the system is constrained to be a compact integrated unit by the water-soluble auxiliary device before being laid, the system finishes the laying in a vertical distribution form of 'suspension on water-underwater suspension' of 'integrated laying' in a water area, and the water-soluble auxiliary device firstly dissolves and releases the connecting cable and then dissolves and disintegrates the bracket according to a preset time sequence after entering water, so that the underwater observation unit sinks and expands into a warm salt profile observation chain within a range limited by the length of the connecting cable, and then self-driven switching from a 'constraint state' to an 'observation state' is finished.
  2. 2. The system of claim 1, wherein the water-soluble auxiliary device comprises a water-soluble scaffold formed from polyvinyl alcohol (PVA) and its modified material and/or carboxymethyl cellulose (CMC), a binding band and a buckle, the material having a tensile strength in the dry state of not less than 30MPa, a wet tensile strength in the immersed state of not less than 5MPa for 30min, a dissolution rate in fresh water at 25 ℃ of 1.2mm/h, a dissolution rate in seawater at 35%o salinity of 1.0mm/h, a dissolution rate deviation of not more than ± 0.1mm/h, a biodegradation rate in 30 days of not less than 90%, and a dissolution product COD of not more than 30mg/L.
  3. 3. The system according to claim 1 or 2, wherein the connecting cable is arranged in three or more sections of a 'piecewise linear constraint', a group of water-soluble binding belts are arranged every 40m, locking structures with descending constraint strength are sequentially arranged along the cable from bottom to top, the locking force is gradually reduced from 10N, 8N, 6N and 4N to 2N, the bottom binding belt is dissolved preferentially after entering water to explain the lower section of the paying-off cable, and the upper binding belt is dissolved to form a 'bottom-up' orderly release process.
  4. 4. The system according to any one of claims 1 to 3, wherein the supporting arm of the water-soluble bracket is provided with a cambered surface lifting structure, the cambered surface radius is 4cm, an anti-slip pad with the friction coefficient more than or equal to 0.6 is arranged at the contact position with the cable, and the underwater observation unit is fixed at the center of the bracket through a water-soluble buckle with the clamping force more than or equal to 5kg and keeps a gap of 5cm with the inner wall of the bracket so as to reduce the interference on water flow and probe sampling.
  5. 5. The system of any one of claims 1 to 4, wherein the water-soluble material forms a hydration layer of about 0.5mm and reduces the surface hardness from about 30HD to about 20HD during 0-30 min, and the overall strength of the bracket remains equal to or greater than 90% of the initial value, wherein the strap is preferentially degraded by small cross section during 30 min-6 h, wherein the bottom strap breaks first at about 2h, the top strap breaks down at about 4h, and the cable is fully released, and wherein the bracket cross-connectors are preferentially thinned to increase the mesh aperture and reduce the resistance, and wherein the longitudinal main struts break down from the buckle after about 6h with a load bearing capacity below the weight of the observation unit.
  6. 6. The system of any one of claims 1 to 5, wherein the floating body unit on water has a draft of 5-8 cm in still water, the floating body is spaced from the top of the bracket by about 1.5m and connected by high-strength fiber ropes to relieve the change of posture caused by waves, and the system is compressed to a nearly cylindrical shape with a diameter of about 50cm and a height of about 60cm before being deployed, so that the system is convenient for manual handling or mechanical lifting.
  7. 7. The system of any one of claims 1 to 6, wherein a sub-float ball having a buoyancy of about 1N is provided along the connection line every 2m, and a weight of about 500g is provided at the bottom end so that the deployed cable tends to hang vertically in the water flow and form an approximately catenary posture with a cable verticality deviation of 5 ° or less.
  8. 8. The system of any one of claims 1 to 7, wherein the underwater observation unit comprises a temperature salt sensor array distributed along the depth direction, the observation depth range is limited to about 5-100 m by the cable length, no solid residue exists in the water body after the water-soluble bracket and the binding belt are completely dissolved, and the dissolved product meets the COD limit value of the pollution control standard of the GB 1886-2001 sewage ocean disposal engineering.
  9. 9. A laying method of an easy-to-lay thermal salt profile observation system is characterized by comprising the steps of integrally putting the system in any one of claims 1 to 8 into a water area, sequentially laying cables in a manner of dissolving binding bands from bottom to top according to a preset time sequence after water-soluble materials absorb water, gradually degrading transverse connecting ribs and longitudinal main supporting columns of a support until the cables are disassembled from a buckle, guiding the cables to form vertical overhang by virtue of floating balls and counterweights, and limiting the sinking depth of an underwater observation unit, so that the thermal salt sensor array completes profile unfolding and enters an observation state.
  10. 10. The method of claim 9, wherein the water absorbing-dissolving-disassembling process comprises the steps of forming a hydration layer and reducing surface hardness by water in the range of 0-30 min, releasing the lower section of the cable by breaking the bottom binding belt in the range of 30min to about 2h, releasing the whole section of the cable by disassembling the top binding belt in the range of about 4h, disassembling the support after about 6h when the support bearing capacity is reduced below the gravity of the underwater observation unit, completely dissolving the support and the binding belt after about 6-8 h, switching the system completion state and starting section observation.

Description

Easily-laid thermal salt profile observation system and laying method thereof Technical Field The invention relates to the technical field of warm salt profile observation, in particular to an easy-to-lay warm salt profile observation system and a laying method thereof. Background In marine environment monitoring, temperature and salt profile data are important bases for understanding the density structure of seawater and the transportation of substances. The existing laying mode is mostly dependent on respectively assembling the floating body, the observing unit and the mooring rope on a deck or a shore base, then putting the floating body, the observing unit and the mooring rope one by one through manual or hoisting equipment and completing tripping and unfolding on the water surface or under water. Such "split" deployment is sensitive to operating windows and sea conditions, often requiring diving or temporary restraint removal with long-pole tools, multiple steps, long time, and susceptibility to safety risks and deployment failure once sea conditions are abrupt. Meanwhile, because the cable and the probe are often integrally restrained or released at one time in an early stage, sudden instability and winding are easy to form, so that collision of an observation unit, knotting of the cable or deflection of the posture are caused, and the forming of a profile chain and the quality of subsequent data are influenced. In order to reduce underwater operation, the technology adopts a timing release, corrosion pin or easy-to-release structure to passively release the binding piece after entering water, but the release rhythm is difficult to finely control along the depth direction, and is often expressed as 'in-phase' unbinding, namely, the cable and the bracket are almost released at the same time, instant stress suddenly changes, the disturbance to the gesture in the initial unfolding stage is large, and local looping is easy to occur in surface turbulence. In addition, the prior temporary support often supports the observation unit by a rigid straight beam or a plane bracket, the support surface and the water flow form additional detours, and local disturbance in the adjacent area of the probe is aggravated, so that the representative drop of sampling and the poor alignment in time and space are caused. In order to improve verticality, some schemes uniformly distribute floating balls on the cable or increase bottom weights, but the sectional constraint and mechanical balancing design matched with the release time sequence is lacked, and the profile chain is still easy to generate larger lateral deflection and swing in a complex flow field. On the other hand, temporary constraint and support materials often adopt non-degradable binding bands, buckles or metal pieces, so that the temporary constraint and support materials are difficult to recycle after being placed, the maintenance cost is increased, and the problem of potential ocean garbage is brought. Even if a hydrolyzable or degradable material is adopted, because the strength and the dissolution rate are difficult to be compatible, the conditions of unmatched dry-wet two-state strength, namely softening and unstability or long-time indistinct are frequently caused, the release process is unpredictable, the deployment success rate is affected, and secondary impact is also possibly caused on observation equipment. The prior art lacks systematic collaborative design among Yi Bu release, controllable time sequence, low disturbance expansion, stable posture and green recovery-free, and is difficult to consider the dual requirements of high-success-rate deployment and high-quality profile observation in a long-term unattended scene. Disclosure of Invention The invention provides an easy-to-lay warm salt profile observation system. The invention solves the technical problems by the following technical proposal: The system comprises an overwater floating body unit, an underwater observation unit, a connecting cable and a water-soluble auxiliary device, wherein the system is constrained into a compact integrated unit by the water-soluble auxiliary device before being laid, the system finishes the laying in a vertical distribution form of 'suspension on water-underwater suspension' of 'integrated laying' in a water area, and the water-soluble auxiliary device firstly dissolves and releases the connecting cable and then dissolves and disintegrates a bracket according to a preset time sequence after entering water, so that the underwater observation unit sinks and expands in a range limited by the length of the connecting cable to form a warm salt profile observation chain, and further self-driven switching from a 'constraint state' to an 'observation state' is finished. In a specific embodiment, the water-soluble auxiliary device comprises a water-soluble bracket, a binding band and a buckle, wherein the water-soluble bracket is formed by polyvinyl alcohol (PVA) a