---a marine deck crane with one or more hydraulic telescopic booms
The hydraulic telescopic boom crane is a marine deck crane with one or more hydraulic telescopic booms. This crane is highly suitable for various general operations in harsh marine environments.
YFM Hydraulic Telescopic Boom Crane mainly uses high-strength steel. Its special jib structure absorbs additional acting forces, protecting the crane from overload and providing extremely high resistance.
The YFM Hydraulic Telescopic Boom Crane is equipped with reinforcing parts and double-layer plates to achieve a smooth transition between elastic and rigid points and prevent the occurrence of stress concentration points.
The YFM cranes are designed to consider the special conditions of marine applications, such as harsh environments, dynamic load situations, and excessive lateral loads and stresses that the crane endures during operation.
Products Data
A marine deck crane of a telescopic boom type with two hydraulic extensions booms for a customer
| Crane Data | ||
| Dynamic moment on base | 4.600 | kN*m (dynamic factor 1.25 |
| Sea state | Harbour conditions | Calm Sea (SWH=0.6mtr) |
| Slewing torque | 500 | kN*m (List/Trim = 5º/2º) |
| Crane weight | ~22.000 | Kg (crane + winch) |
| Oil flow, Q, recommended | 250 | l/min |
| Working pressure required | 300 | bar |
| Oil tank capacity recommended | 1.000 | Ltr (later ) |
| Slewing sector | 360° | Unlimited, |
| Slew time | 0.6 | Rpm @ Q l/min |
| No. of slewing gear | 2 | - |
| Luffing time | 75 | sec (average in/out/) |
| Extension time | 75 | sec (average in/out) |
| E-power supply required: | 24V / 50Hz | Stabilized power supply - 5A |
| Design Data | ||
| Design temperature | -10ºC~+45ºC | |
| Flag state | The Netherlands | |
| Capacity by a hook at the boom end | SWL | Outreach |
| Single fall use | 7.500kg | 3.50-20.00mtr |
| Quarterly fall use | 26.600kg | 11.00mtr |
| 17.700kg | 15.25mtr | |
| 14.000kg | 19.50mtr | |
| Main Winch Data | ||
| Safe Working Load (SWL) | 7.500kg | on 3rd layer-single fall- |
| Number of falls | Quarterly fall | |
| Hook speed, Quarterly fall, single fall | 0-6 m/min, 0-25 m/min | With 26.600 kg line pull With 7.500 kg line pull |
| Wire rope length | 90m | |
| Max. lowing depth | 75m | Under boom tip (hook travel-single fall) |
| Hook stop up, limit switch | Electric type | Stainless steel proximity switch |
| Hook stop down, limit switch | Electric type | Stainless steel proximity switch |
Note: The parameters of this table are conventional configurations and can be redesigned according to users' working conditions.
What safety devices does a crane have?
The necessary components and safety devices are installed to operate the marine crane for its intended purpose and safe operation; the crane's safety system comprises the following:
- Relief valves set to values corresponding to the ship crane capacities protect all primary hydraulic circuits from overpressure.
- A main over-pressure valve to ensure the safety of the entire hydraulic system.
- Slewing machinery: a load-holding valve that freezes the motion of the slewing motor in case of hydraulic pressure drop and a failsafe multi-disc brake.
- All hydraulic cylinders have a hydro-piloted block load holding valve that freezes the motion in case of a hydraulic pressure drop.
- Every lever of operation is spring loaded and returns automatically to zero position (deadman's- handle) once force is no longer applied to the lever.
- A hydraulic overload (limiting moment) device ensures that all crane functions stop during winch overload. When the marine crane is stopped, the only allowable motion is lowering the load; all other movements are blocked.
What work needs to be done regarding Marine cranes for surface treatment in a marine environment?
To enable the marine crane to function as a lifting device in an environmentally friendly, stable, and long-lasting manner in a marine environment, we spare no effort to provide the most suitable surface treatment method for the marine environment：
- All steel plates undergo careful stress relief and are shot-blasted (SA 2.5) to remove all rust and impurities before painting.
- The crane and all its components are thoroughly washed before painting to eliminate oil and dust from all surfaces and ensure maximum paint adhesion. This also applies to the slewing bearing, gearboxes, brake valves, and motors.
- Crane components are disassembled, sandblasted, painted piece by piece, and reassembled.
- Special attention is given to sealing flanges, openings, and cavities where seawater may enter or accumulate.
- The marine paint system includes one layer of zinc primer applied right after shot blasting, two intermediate layers of epoxy paint, and one layer of polyurethane topcoat, with a total thickness of 280µm.
- Platforms and railings are galvanized.
- The column, booms, and other steel members with openings exposed to the weather are also painted on the inside.
- All pins are made of 42CrMo4, and their exposed areas are painted separately from the rest of the crane. After installation, the lugs of the pins are sealed to prevent seawater from entering.
- The piston rod of the luffing cylinder(s) is made of S355 steel with a LUNAC 2+ surface treatment, providing the highest resistance to the salty environment. The cylinder rods of the extension cylinders are treated on the rod surface with Nikrom® 500.
- All hydraulic pipelines are made of stainless steel (AISI 316). The pipe and hose couplings treated with cadmium are protected by Denso tape or equivalent.
- The external hydraulic hoses are heavy-duty and resistant to sunlight and seawater.
- Where possible, all hydraulic hoses are bundled together and protected by a hard plastic spiral cover.
- Surfaces of flanges, bolt threads, pin lugs, etc., where steel is in contact with steel, are protected by a special marine grease to prevent adhesion and rusting.
- The heads of the bolts fixing the slew bearing and slew gear(s) to the crane's rotating column are covered by plastic caps filled with marine grease.
- All nuts and bolts are made of stainless steel (AISI 316), except for connections that require high-tensile bolts (which are zinc-plated).
- All grease nipples are made of stainless steel (AISI 316).
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