The Dawson EMV-300 is a metric excavator-mounted vibrator designed for piling operations, including driving and extracting piles. It is a versatile tool that can be easily adapted to various excavators, providing a highly productive pile driving machine. The EMV-300 is suitable for driving and extracting sheet piles, H-beams, and other pile types.
Function Description:
The EMV-300 operates by generating high-speed contra-rotating eccentric weights that produce vertical vibratory forces. These vibrations are transmitted to the pile, creating a powerful hydraulic grip that allows the pile to be vibrated at the same speed and displacement as the gearbox itself. This vibration effect fluidizes the soil around the pile tip, making it easier to drive or extract the pile. The fluidizing effect allows soil particles to shuffle themselves around, creating space for the pile to move into or out of the ground. The EMV-300 is particularly effective in cohesive and extremely dense soils, as well as in sands and gravels where vibrators work best. The dense clay soil does not allow soil particles to shuffle easily, but the EMV-300's vibratory action can still cause a fluidizing effect.
The EMV-300 is powered by the excavator's hydraulic system, which supplies adequate pressure and flow rate. It features a built-in flow regulator that limits the oil flow rate supplied to the drive motor, ensuring optimal performance and preventing excessive bearing loads. An additional safety feature is the flow regulator sequence valve, which prevents the vibrator from running until the adequate clamping force has been applied to the pile.
Important Technical Specifications:
- Static Moment: 4.6 Kg.m (400 lbs.in)
- Frequency: 2400 r.p.m. (2400 r.p.m.)
- Centrifugal Force: 300 kN (67,420 lbs)
- Amplitude: 12.7 mm (0.58 ins)
- Max. Hydraulic Flow Rate: 130 l/min (34 gpm)
- Min. Hydraulic Flow Rate: 250 l/min (67 gpm)
- Max. Hydraulic Pressure: 350 bar (5,076 psi)
- Max. Hydraulic Power: 76 kW (102 hp)
- Dynamic Mass: 625 Kg (1,380 lbs)
- Total Mass: 860 Kg (1,890 lbs)
- Max. Pile Mass: 7000 Kg (15,400 lbs)
- Max. Push/Pull Force: 15,000 Kg (33,000 lbs)
- Max. Push/Pull Deflection: 146 mm (5.75 ins)
- Dimensions:
- A: 835 mm (32.8 ins)
- B: 150 mm (6 ins)
- C: 250 mm (10 ins)
- D: 880 mm (34.6 ins)
- E: 425 mm (17 ins)
- F: 927 mm (36.5 ins)
- G: 1200 mm (47.25 ins)
- H: 75 mm (3 ins)
- Min. Pile Width: 250 mm
- Max. Pile Thickness: 30 mm
Usage Features:
- Mounting: The EMV-300 is mounted to the excavator's bucket using a shear pin and adaptor brackets. Different adaptor brackets are available for various excavators and machine sizes. The bucket must be removed prior to installing the EMV.
- Hydraulic Connections: The EMV-300 requires specific hydraulic fittings for pressure and return lines (metric 20 S) and a drain line (metric 15 L). Quick release couplings are recommended for easy installation and removal.
- Preparations: Before driving/extracting piles, ensure the equipment is functioning correctly and that the EMV method of piling is implemented efficiently. Bundles of sheet piles should be set out on the job site, and piles should be adequately lubricated.
- Driving Piles: The excavator bucket ram control function is used to operate the vibrator. The vibrator should be lowered onto the pile, ensuring the pile is pitched correctly. The clamp should be fully engaged on the pile top, and the lifting chain fitted. The vibrator should be started gently and gradually increased to full speed.
- Extracting Piles: Similar to driving, the vibrator is lowered onto the pile, and the clamp is engaged. The vibrator is started, and the extraction force is gradually increased. The pile should be extracted until the pile foot is almost extracted, then the vibrator should be stopped, and the pile pulled out the remaining short distance.
- Safety: Operators must be suitably qualified and trained. The working area should be well-lit and clear of underground obstacles. The danger area around the vibrator is defined as a 15m (50') radius. Personal protective equipment, including ear protection, must be worn.
Maintenance Features:
- Daily Maintenance:
- Grease the two grease points on the EMV300 (one on the Saddle Swivel and the other on the side of the Clamp Body).
- Visually inspect all visible screws, bolts, fittings, etc., for tightness.
- Visually inspect all hydraulic hoses and fittings for leaks or damage.
- Check the gear oil level in the vibrator.
- Inspect the lifting chain and chain clamp for damage.
- Inspect the condition of the Hard Jaws for wear.
- Every 50 Working Hours:
- Change the oil in the vibrator gearbox. Remove the drain plug from the bottom of the gearbox and the breather/filler plug from the top. Allow the oil to drain completely into a suitable container. Replace the drain plug and fill with new clean oil through the breather/filler hole until the oil level in the gearbox is approximately half-way up the sight glass (approximately 4 litres or 1.05 US gallons).
- Re-fit the breather/filler plug using a new seal and tighten.
- The old oil must be taken to a certified waste disposal centre.
- Every 1000 Working Hours:
- The unit should be inspected and serviced by the manufacturer or an approved Dawson distributor. This includes a comprehensive check for structural integrity, wear, and potential problems.
- Troubleshooting: The manual provides detailed troubleshooting steps for common issues such as the EMV clamp not closing, the unit not vibrating, the unit not running at the correct speed, oil blowing out of the motor blow-off valve, oil blowing out of the gearbox breather valve, and the clamp closing itself immediately after being opened.
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