DREVO Adaptive Air Buoyancy System

DREVO Adaptive Air Buoyancy System

Inflatable additional buoyancy cylinders for the DREVO River Cargo Platform L-7 Expand

1. Concept

DREVO Adaptive Air Buoyancy System (AABS)— a system of automatically deployable and inflatable balloons designed to temporarily increase displacement, reduce draft, compensate for overload and improve platform stability.

The cylinders are located along the outer sides of the main pontoons and, when folded, are stored in protected niches. As the load increases, they expand, fill with air, and create additional displacement volume.

The main principle:

Additional cylinders increase buoyancy reserve, but do not replace a strong hull, calculated load capacity and center of gravity control.

2. Main tasks of the system

AABS is used for:

temporary increase in lifting capacity;

reducing draft when passing through shallow water;

compensation for uneven loading;

increasing transverse stability;

emergency support of the platform in case of damage to the pontoon;

stabilization during loading;

improving safety during self-unloading;

transportation of light bulk cargo;

return of the overloaded platform to the nearest shore station.

3. Physical principle

Additional buoyancy is determined by the volume of water displaced by the cylinders.

In fresh water:

1 m3 of immersed volume creates approximately 1 000 kg of theoretical lifting force;

0.5 m³ — about 500 kg;

2 m³ — about 2,000 kg;

4 m³ — about 4,000 kg.

However, the entire theoretical volume cannot be considered as useful carrying capacity.

It is necessary to take into account:

incomplete immersion of cylinders;

the weight of the cylinders themselves and the compressor system;

dynamic loads;

roll and trim;

freeboard reserve;

the influence of currents and waves;

the possibility of damage to one of the cylinders.

The practically safe additional working load should be about50–70% of the theoretical buoyancy of the cylinders.

4. Proposed configuration

For a 7.0 m long platform, four main cylinders are provided:

left front;

left rear;

right front;

right rear.

Additionally, two aft stabilizing cylinders can be installed for self-unloading.

Size of one main cylinder

Preliminary dimensions:

The exact volume depends on the shape of the cylinder and the available space along the pontoons.

5. System options

AABS-2

Two side cylinders.

Total additional volume:

1.5–2.5 m³.

Theoretical buoyancy:

1.5–2.5 t.

Recommended additional operating load:

0.8–1.5 t.

Applicable for:

compensation of average overload;

reduction of sediment;

increasing stability.

AABS-4

Four sectional cylinders.

Total additional volume:

3–5 m³.

Theoretical buoyancy:

3–5 t.

Recommended additional operating load:

1.5–3 t.

Applicable to large platformRCP L-7 Expand.

AABS-6 Heavy

Four side and two aft cylinders.

Total additional volume:

5–7 m³.

Theoretical buoyancy:

5–7 t.

Operationally used reserve:

about 2.5–4 tons.

This option only applies to:

on calm water;

at reduced speed;

on short routes;

under constant stability control.

6. Recommended diagram for RCP L-7 Expand

Optimal basic configuration:

Theoretical additional buoyancy:

about 4,000 kg.

Rational operational reserve:

about 2,000–2,800 kg.

Thus, a platform with a basic nominal load of 2–3 tons can transport for a short time:

up to 4–5 tons with the system fully deployed;

only if the frame strength and safe positioning of the center of gravity have been confirmed.

Cylinders do not automatically increase the permissible load of the power frame, deck, unloading mechanisms and container fastenings.

7. Design of cylinders

Multilayer construction is recommended.

Inner sealed layer

Materials:

thermoplastic polyurethane;

reinforced polyurethane elastomer;

butyl rubber sealed chamber.

Power layer

Used:

polyester fabric;

aramid fiber;

High-strength fabric with diagonal reinforcement.

Protective outer layer

Protects against:

stones;

branches;

metal waste;

ultraviolet;

petroleum products;

abrasion.

Possible materials:

reinforced Hypalon/CSM;

TPU with additional protective shell;

replaceable polyurethane pads.

8. Sectioning

Each long cylinder must be divided into at least three independent air chambers.

For example:

front section;

central section;

rear section.

If one chamber is damaged, most of the buoyancy is retained.

Each camera receives:

separate valve;

pressure sensor;

emergency check valve;

safety valve;

possibility of independent inflation.

9. Accommodation

Cylinders are installed:

outside the main pontoons;

below the cargo deck;

as low as possible relative to the center of gravity;

symmetrically on both sides.

In the folded position they are:

in rigid protective cassettes;

behind folding or sliding panels;

above the line of constant friction with water.

When activated, the cassette opens, the balloon comes out and inflates.

10. Inflation system

There are two possible air sources.

Electric compressor

The main option.

Advantages:

multiple use;

smooth volume regulation;

lack of replaceable high-pressure cylinders.

Suggested configuration:

two independent compressors;

productivity of each 500–1,500 l/min;

working pressure up to 0.5 bar;

separate backup circuit.

Compressed air cylinders

Emergency option.

Used for:

quick release;

electrical system failures;

damage to the main pontoon.

Compressed gas should not be the only activation method.

11. Deployment time

Approximate values:

The system can inflate only the required sections, not the entire set at once.

12. Automatic control

DREVO AI receives data from:

container load cells;

precipitation sensors;

roll sensors;

trim sensors;

NOSE;

cylinder pressure sensors;

surveillance cameras;

current and wave sensors.

The system automatically detects:

which balloon needs to be inflated;

required air volume;

permissible speed;

the need to stop loading;

Is the route to the coastal station safe?

Example:

the left aft sector is overloaded;

the left rear cylinder is automatically inflated;

If necessary, the right rear cylinder is partially inflated to increase overall stern buoyancy.

13. Operating modes

Normal

The cylinders are folded.

The main buoyancy of the pontoons is used.

Stability Assist

The cylinders are partially inflated.

Used by:

during loading;

when operating the manipulator;

with uneven load;

during parking.

Shallow Water

The balloons are fully or partially inflated to reduce draft.

Heavy Cargo

Cylinders create additional displacement when transporting heavy cargo.

Docking Support

The stern cylinders stabilize the platform during self-unloading.

Emergency Float

All working chambers automatically inflate when:

damage to the pontoon;

a sharp increase in precipitation;

dangerous move;

water entering the body.

14. Effect on sediment

Additional cylinders can reduce draft, but the effect depends on the shape of the main hulls.

Approximately an additional volume of 2–4 m³ can:

compensate for 2–4 tons of full displacement;

reduce the draft of the loaded platform by approximately 0.10–0.30 m;

increase the freeboard;

ensure passage of smaller sections.

The exact change in draft is determined by hydrostatic calculation of the hull.

15. Influence on width

When the cylinders are deployed, the overall width of the platform increases.

This limits:

passing through narrow channels;

work at bridge supports;

mooring;

transportation by land.

Before inflating, DREVO AI must check the free space around the platform.

16. Effect on water resistance

Fully inflated side bladders:

increase hydrodynamic resistance;

reduce speed;

impair maneuverability;

increase sensitivity to crosswinds.

Recommended restrictions:

17. Loads on fasteners

Each cylinder transmits significant vertical and lateral forces to the frame.

With a lifting force of one cylinder of 800 kg, its fastenings must be designed for at least:

static load 800 kg;

dynamic load 1,200–1,600 kg;

longitudinal forces from the current;

impact loads from debris and waves.

Recommended:

at least four power attachment points per section;

load distribution through the longitudinal beam;

the safety factor of fasteners is not less than 2;

separate emergency restraining straps.

18. Protection from damage

The following is provided:

rigid external bump stops;

replaceable protective pads;

mesh covers;

leak detectors;

automatic pressure maintenance;

emergency isolation of the damaged chamber.

Cylinders should not be the first point of contact with:

bridge supports;

along the shore;

large boulders;

metal structures.

19. Restrictions

Additional air tanks do not solve the following problems:

insufficient strength of the power frame;

cargo deck overload;

weak self-unloading mechanism;

too high center of gravity;

poor cargo securing;

uneven loading;

insufficient power of the propellers.

The system increases buoyancy, but does not automatically make dangerous cargo safe.

20. Updated load capacity

The last line does not indicate permission for the scheduled transportation of 6 tons. This is an emergency or special mode requiring separate engineering approval.

21. Updated system mass

This tare weight reduces some of the additional payload capacity.

22. Recommended final configuration

For the first prototype it is recommended:

four independent cylinders;

total volume 3–4 m³;

operational reserve of lifting capacity 1.5–2.5 t;

two electric compressors;

emergency receiver;

three-section design of each cylinder;

automatic roll control;

speed limit with the system open;

mechanical protection of cylinders;

prohibition of automatic increase of the permitted mass without DREVO AI verification.

Conclusion

The system of inflatable additional cylinders significantly expands the possibilitiesDREVO River Cargo Platform L-7 ExpandIt allows for a reduction in draft, stabilization of the platform, compensation for uneven loading, and the creation of a temporary buoyancy reserve of up to several tons.

It is most rational to use cylinders in three cases:

for transportation of light bulk cargo;

for short-term increase in buoyancy during overload;

as an emergency platform rescue system.

For a basic configuration, it is reasonable to provide about4 m³ of additional air volume, which provides approximately4 tons theoreticaland around2–2.8 tons of safely usable additional buoyancy.

The final permitted load capacity must be determined not only by buoyancy, but also by frame strength, platform stability, center of gravity height, load distribution, and self-unloading system capabilities.