Underwater Tools: Hydraulic & Pneumatic Systems Guide

Posted on Sep 7, 2024 in Technology

Underwater Tools

Hydraulic Tools

Operation: Based on the transmission of energy through fluid.

  • Energy is harnessed by a hydraulic motor, transforming it into mechanical work energy.

Component Parts:

  • Engine: An explosion or mechanical generator supplying electric power to the hydraulic pump.
  • Hydraulic Pump: Communicates mechanical energy to the engine through the fluid. Maintains adequate flow and pressure.
  • Fine Filter: Filters impurities from the oil to prevent system clogging.
  • Gauge: Indicates oil pressure in the output circuit.
  • Hydraulic Accumulator: A small steel and neoprene cylinder dipped in nitrogen at 100 ata, absorbing pressure shocks and maintaining constant oil pressure and flow. Includes a pressure relief valve to limit maximum pressure.
  • Non-Return Valve: Prevents fluid backflow.
  • Quick Connector: Connections between the central hydraulic hose and hydraulic tool distribution. Blocked upon connection to retain fluid.
  • Hose Distribution: Transports fluid to the hydraulic unit and the tool, returning it to the plant.
  • Deposit: Stores hydraulic fluid without pressure. Cools, removes impurities, and eliminates bubbles.
  • Hydraulic Tools: Converts pressure and flow into two types of movement:
    • Rotary Movements: Drills, brushes, etc.
    • Linear Movements: Hoists, hydraulic trifors.
    • Reciprocating: Piledriver, punching.

Pneumatic Tools

Definition: Tools driven by compressed air, using air as the fluid to transmit energy.

System Components:

  • Compressors: Rotary-type air pressure generators, powered by diesel or electricity. Minimum flow rate is 3500 to 15000 l/air at a pressure of 7 ata.
  • Hoses: Standard diameter is 2 inches, length ranges from 3 to 15 m. Equipped with quarter-turn couplings for compressor connection. Air enters the tool’s engine and is expelled outwards.
  • Lubrication Elements: Located at the compressor outlet, supplying oil to the entire system and the tool. Essential for underwater tools.
  • Tools: Operate on the principle of air entering the engine, generating pressure that produces two types of movement:
    • Rotary Movements: Drills, impact wrenches, etc.
    • Reciprocating: Hammers, cutters.
    • Agreeing Movements: Drills, hammer drills, etc.

Evaluation of Pneumatic vs. Hydraulic Tools:

Pneumatic Tools:
  • Cheaper
  • More manageable with only one hose
  • More difficult energy supply
  • Compressed air can be used by divers
Hydraulic Tools:
  • Smaller
  • Greater versatility
  • Total torque and rpm control
  • No bubble emission
  • Quieter
  • Greater tool durability
  • Increased working depth
  • More power

Compressors

Pressure: The force exerted by the compressor.

  • At 0°C and 760 mm/Hg, there are 2.7 x 1019 molecules with space between them, allowing for compression.
  • Air acts as the energy carrier.

Compressor Operation:

  • Takes outside air and elevates its pressure to power the tool and produce work.
  • The driving force provides energy for air compression.
  • The motor can be explosive, combustion-based, or electric.
  • Motor characteristics depend on the air volume it can provide.
  • The compressor delivers air at a specified pressure above atmospheric pressure, storing it in a tank or drum to meet the tool’s needs. A manometer indicates pressure in the shell (in atmospheres or kg/cm2).
  • Suitable pressure for pneumatic tools is 6 ata.
  • Higher pressure can cause tool wear, fatigue, and increased risk for the diver.
  • Valves must be connected to a compressor control system, operating in a vacuum with the boiler’s maximum allowable pressure.
  • A charge controller keeps the engine at full power when air is not needed.

Compressor Regulation:

  • Depends on compressor power, the tool used, and its operation.
  • Air consumption variations cause pressure differences in the kettle.
Regulation by Safety Valve:
  • A safety valve is placed in the compressed air duct leading to the kettle and set to a maximum pressure.
  • When compressed air is not consumed, pressure in the kettle increases until it reaches the set maximum, triggering the safety valve to release excess air.
Regulation by Pilot Valve:
  • The system operates the compressor in a vacuum, minimizing engine power consumption.
  • Vacuum operation can be achieved by closing the inlet and outlet during air intake or by using a pilot/regulator valve between the compressor and the boiler, driven by reservoir air.

Types of Hand Tools

Cutting Tools:

Wood and Metal Saws:
  1. Materials of Manufacture:
    • High-speed steel or carbon steel
    • Steel
  2. Tooth Pitch:
    • Number of teeth per 25 mm
  3. Tooth Set:
    • Arrangement of teeth on the blade
  4. Tooth Shape:
    • Straight with spacing
    • Rounded with spacing
  5. Wood Cutting Saws:
    • Made of mild steel
    • ¾ teeth per 25 mm
    • Clear tooth set
    • Straight teeth
  6. Metal Cutting Saws:
    • Made of fast, ultra-fast steel
    • 12 to 15 teeth per 25 mm
    • Straight tooth set
    • Rounded teeth
Crowbar:
  • Used to cut metal by impact (chains, ropes, sheaves, etc.)
  • Types:
    • Flat: for cutting or deforming
    • Vedado or cross-cutting: for cables
    • Semicircular: for stranding
    • Diamond punches
Files and Rasps:
  • Rasps:
    • Made of cast steel or cast iron with large, triangular teeth
    • Used for shaping and smoothing soft materials
    • Types: straight, round, and medium reeds
  • Files:
    • Made of hardened steel with fine striations in one or more directions
    • Used for abrading and smoothing
    • Types: straight and half-round rods

Drilling Tools:

  • Brace
  • Chest Drill
  • Manual Drills
Drill Bits:
  • Classified by base and purpose
  • According to the base: tapered shaft, straight shaft, SDS Plus
  • According to purpose:
    • For metal: high-speed steel, steel and cobalt, steel and titanium
    • For concrete or rock: from nVidia, diamond
    • For wood
Reaming:
  • Used to improve the finish or enlarge hole diameter up to 25 mm
  • Shapes:
    • Straight flute: manual
    • Spiral grooves: machines
    • Cuff
    • Cone

Threading Tools:

Interior Taps:
  • Made of high-speed steel with 4 cutting planes
  • Types:
    • Taper: to align and start thread cutting
    • Intermediate: to continue and finish cutting through holes
    • Bottoming: to finish cutting blind holes
Interior Die:
  • Types include taper, intermediate, bottoming, and key taps
Exterior Taps or Bolt Taps:
  • Used for manufacturing or repairing threaded bolts
  • Types:
    • Nut Taps: requires no special key, only for bolt repair
    • Solid Taps: creates new hexagonal screws
    • Section Taps: for threading bolts with diameters larger than designed

Pneumatic Operating Machines

Definition: Tools that convert compressed air pressure and flow into energy.

Components:

  • Air motor
  • Compressor: compresses air at a given pressure and flow, storing it in the kettle
  • Compressor Types:
    • Piston: lower flow, higher pressure, less oil
    • Diaphragm: lower flow and pressure, less oil
    • Rotary Vane: lower flow and pressure, silent
    • Screw: most commonly used, higher flow and pressure
    • Lobe (Roots): forces air, medium flow, low pressure
    • Radial Turbochargers: high flows and pressures, very complex
    • Axial Turbochargers: large flows, high pressures, high operating speed, very complex

Filtration and Lubrication Elements:

  • Water Separator: eliminates condensation in the circuit
  • Flow Regulator: controls pressure and flow supply
  • Lubricator: provides constant oil supply for tool lubrication

Hoses:

  • Transmit the pressure and flow required for machine operation
  • Lengths range from 3 to 25 m
  • Equipped with 2, 3, or 4-arm crab connectors

Tools:

  • Convert air flow rate and pressure into mechanical energy (rotation or percussion)
  • Motor can be vane, screw, or piston type

Pneumatic Tool Types:

  • Rotary: drills, grinders, radial drills, screwdrivers
  • Percussion: hammer breakers, sheet cutters, hammer drills

Pneumatic Dredge

  • A vacuum tube (10-20 cm diameter) with a rigid section (1-1.5 m) at the beginning
  • A pressurized air nozzle pointing towards the surface is located in the first few centimeters of the tube
  • Used for removing mud and sand in small areas
  • Maximum aspiration depth of 2 m
  • Intake pipe must be nearly vertical

Lifting Balloons

Definition: A flexible container filled with air, utilizing Archimedes’ principle to lift objects from the seabed to the surface.

Types of Lifting Balloons:

Open:
  • Require a safety valve
  • Open at the bottom
  • Lift the maximum force for which they are designed
Closed:
  • Require a safety valve
  • Lift any weight within their design capacity

Hydraulic Machines

Types:

Closed Circuit:
  • Operate with oil or other fluids, transferring energy to the tool’s hydraulic motor
Open Circuit:
  • Operate with water or the fluid in which they are immersed, utilizing pressure for cleaning, cutting, stripping, etc.

Components:

  • Hydraulic Pump: Converts hydraulic energy into fluid kinetic energy
  • Hoses: Carry oil to and from the tool
  • Tool: Converts fluid kinetic energy into mechanical energy (rotation, percussion, etc.)

Central Hydraulics:

Components:
  • Hydraulic Pump: Driven by an electric or internal combustion motor, raising pressure from 60 to 2000 bar
  • Reservoir: Stores fluid for cooling
  • Filters: Prevent clogging of the pump and tool
  • Accumulator: Equipped with a non-return valve to keep hoses full

Hoses:

  • Reinforced flexible hose, withstanding pressures from 60 to 2000 bar
  • Equipped with quick couplings and non-return valves
  • Always coupled
  • Pressure loss occurs per meter or diameter of the hose

Tools:

Types:
  • Rotary Drilling: manual drills, fixed drills, drilling rigs, borers, impact wrenches
  • Cutting: grinders, radial grinders, diamond saws
  • Cleaning: brushes and pumps
  • Percussion: hammers and nailers
  • Other: tractel, bolt tensioner

Hydraulic Cleaning Tools

Pressure Washers:

  • Use water at 500 to 2000 bar for cleaning
  • Used to clean metal structures, boat hulls, and cut soft mud or stone
  • Equipped with a reaction force barrel to counterbalance the main gun and the diver
  • Jamming can be dangerous for the diver

Cavitation Cleaning Machines:

  • Achieve similar results as high-pressure water cleaning
  • Water pressure is 10 to 15 bar
  • Safe for the diver
  • Can clean metal parts, plastics, rubbers, and marine fouling
  • Pistol is small and recoil-free

Hydraulic Vacuum:

  • Similar to a vacuum cleaner but uses special pumps instead of compressed air
  • Advantages:
    • Aspirates at any angle due to suction
    • Smaller size with the same suction power
  • Disadvantages:
    • Aspiration depth decreases with depth, and discharge occurs near the diver

Attachment Fittings

Chemical Anchors:

  • Used for attaching metal plates or anchors
  • Can be placed underwater
  • High load resistance
  • Almost unlimited stability against water action
  • Types:
    • Blisters:
      • Three components: epoxy resin, catalyst, amalgamator
      • Types include glass and flexible
    • Anchors:
      • Made of stainless steel
      • Chamfered tip
      • With nut and washer
  • Placement Tools: Ancillary tools for inserting anchors and mixing components securely
  • Accessories: Threaded elements for anchoring and securing objects

Placement of Chemical Anchors:

  1. Make the hole:
    • Use a hydraulic or pneumatic drill with the correct drill bit size
    • Drill perpendicular to the surface
    • Drill to the exact depth
  2. Clean the hole:
    • Use a ramrod or compressed air
  3. Insert the blister:
    • In the specified direction
    • Ensure it does not break
  4. Place the anchor:
    • Use a rotary or percussion tool
  5. Attach the nut:
    • After the setting is complete
    • With the correct torque

Pistols and Bolts:


– Tool attachment that fires explosive rounds, firing piers, pins, punches, rolls, etc.. …
– The advantage is that it carries out threading, drilling and bolted into a single movement, thus facilitating the work of the diver in the repair and quick fasteners.

– Types:
– Gun Bolt bolted submersible submersible COX COX.
– Hammer of amphibian cartridge tornado T6-U.