轮机全部课件英语lesson

1、Harbin Engineering UniversityLesson 19Cargo handling equipment(货物装卸设备)Harbin Engineering UniversityThe various items of machinery and equipment can be found outside of the machinery space.Harbin Engineering UniversityThese include deck machinery such as mooring equipment(系缆设备), anchor handling equip

2、ment(抛锚设备), cargo handling equipment and hatch covers(舱口盖). Harbin Engineering UniversityOther items include lifeboats(救生艇) and liferafts(救生筏), emergency equipment, watertight doors, valve actuator, stabilizers(减摇装置) and bow thrusters(船头推进器). Harbin Engineering UniversityThe cargo handling equipment

3、 will now be described.Harbin Engineering UniversityCargo winches are used with various derrick(吊杆) systems arranged for cargo handling. Harbin Engineering UniversityThe unit is rated according to the safe working load to be lifted and usually has a double speed provision(装置) when working at half lo

4、ad.Harbin Engineering UniversityIn the cargo winch, spur reduction gearing transfers the motor drive to the barrel shaft. Harbin Engineering UniversityA warp end(卷绕端) may be fitted for operating the derrick topping lift (顶牵索) (the wire which adjusts the derrick height). Harbin Engineering University

5、Manually operated band brakes may be fitted and the drive motor will have a brake arranged to fail-safe(故障保护), i.e. it will hold the load if power fails or the machine is stopped.Harbin Engineering UniversityA derrick rig(装置) is known as union purchase(双杆联吊装置). Harbin Engineering UniversityOne derri

6、ck is positioned over the quayside and the other almost vertically over the hold(货舱). Harbin Engineering UniversityTopping wires fix the height of the derricks and stays(稳索) to the deck may be used to prevent fore and aft movement.Harbin Engineering UniversityWinchesDerricksTopping wiresCargo handli

7、ngwiresHarbin Engineering UniversityCargo handling wires run from two winches and join at the hook. Harbin Engineering UniversityA combination of movements from two winches enables lifting, transferring and lowering of the cargo.Harbin Engineering UniversityCranes have replaced derricks on many mode

8、rn ships. Harbin Engineering UniversityPositioned between the holds, often on a plateform which can be rotated through 360, the deck crane provides an immediately operational unit requiring only one man to operate it.Harbin Engineering UniversityVarious types of crane exist for particular duties. Ha

9、rbin Engineering UniversityIn a general cargo crane, three separate drives provide the principal movements: Harbin Engineering Universitya hoisting(起升) motor for lifting the load, a luffing(变幅) motor for raising or lowering the jib(boom), and a slewing(旋转) motor for rotating the crane. Harbin Engine

10、ering UniversityThe crane is usually mounted on a pedestal(底座) to offer adequate visibility to the operator. Harbin Engineering UniversityFor occasional heavy loads, two cranes can be arranged to work together. Harbin Engineering UniversityThe operating medium for deck crane motors may be hydraulic

11、or electric.Harbin Engineering UniversityThe use of hydraulic drives in cranes, winches and similar equipment is now accepted as a conventional method of drive in many case. Harbin Engineering UniversityMany reasons can be suggested for the use of hydraulic systems in marine engineering:Harbin Engin

12、eering Universitya) A convenient method of transferring power over relatively long distances from, say, a central pump room to remote operating sites. Harbin Engineering Universityb) Fully variable speed control of both linear and rotary motion, with good inching capability and smooth take up of loa

13、d. Harbin Engineering Universityc) High static forces or torques can be achieved and maintained indefinitely(无限期地). Harbin Engineering Universityd) Complete safety and reliability is assured under the most difficult environmental conditions; Harbin Engineering Universityoverload conditions are safeg

14、uarded by using a relief valve to limit maximum output torques or forces. Harbin Engineering UniversityThe wide range of high torque, low speed motors are available for driving winch drums directly so dispensingwith(免除) the need to fit reduction gearing. Harbin Engineering UniversityMotors of this t

15、ype are more common on larger cranes where reduction gearboxes would be expensive. Harbin Engineering UniversityAll fixed capacity motors, whether high or low speed, require a high flow at low pressure to obtain high light hook speeds and consequent short cycle times. Harbin Engineering UniversityWi

16、th large cranes this can e an embarrassmentand one solution with low speed motors is to use the two speed type to double the speed and half the output torque at light hook load. Harbin Engineering UniversityHigh speed motors with reduction gearing have the advantage that the brake can be mounted on

17、the high speed shaft and so be much smaller and cheaper. Harbin Engineering UniversityBecause of the availability of standard low cost gearboxes this arrangement is popular on light cranes. Harbin Engineering UniversityVariable capacity axial piston motors have the important advantage that light hoo

18、k speeds can be increased up to four times from a given oil flow by reducing the motor capacity to 25 per cent of the maximum. Harbin Engineering UniversityHydraulic Crane The hoisting of the cargo is effected by a hoisting winch driven by a hydraulic motor that Harbin Engineering Universitythat pro

19、vides a constant torque in both directions of rotation and at all speeds within the regulation range of the motor. Harbin Engineering UniversityThe winch is equipped with a mechanical belt brake that acts on the outside of the rotating motor housing. Harbin Engineering UniversityDuring operation, th

20、e brake is released by means of oil pressure which compresses a spring. Harbin Engineering UniversityThe crane jib is raised and lowered by means of a luffing winch which is constructed in a similar manner to the hoisting winch. Harbin Engineering UniversityThe pumps are axial piston pumps and are d

21、riven by a common 3-phased synchronous motor(三相同步电动机) at a constant speed of rotation. Harbin Engineering UniversityThe capacity of the pump is changed by turning the swashplate. Harbin Engineering UniversityThe crane is turned by a hydraulic motor of the same type as that described above, in that t

22、he rotor turns a pinion which engages with a toothed ring on the crane housing. Harbin Engineering UniversityAn oil cooler is used to remove the heat generated in the oil during the operation of the crane. Harbin Engineering UniversityThe system is also provided with a preheater for heating the oil

23、in cold weather. Harbin Engineering UniversityIf the temperature of the oil reaches 85oC, a thermostat(温度调节装置) in one of the oil lines switches off the electric motor. Harbin Engineering UniversityPressure relief valves are built into the system to protect the system and the crane against excessive

24、loads. Harbin Engineering UniversityAll moving parts in the hydraulic system are lubricated by means of the oil in the system. Harbin Engineering UniversityThe crane housing, which is a welded construction on a rigid baseplate, contains all the mechanical machinery, the hydraulic system and the elec

25、tric equipment. Harbin Engineering UniversityThe tops of the crane housing and the jib carry blocks(滑轮组) for wires for the hoisting of the cargo and the raising of the jib. Harbin Engineering UniversityAll of the blocks have enclosed ball bearing. Harbin Engineering UniversityBoth the luffing winch

26、and the winch for turning the crane are operated from the same control handle. Harbin Engineering UniversityA small movement of this control handle either forwards or backwards results in the build up of oil pressure in the control oil line and the piston in the brake cylinder releases the brake. Ha

27、rbin Engineering UniversityMovement of the control handle further than the position for releasing the brake starts the luffing winch. Harbin Engineering UniversityThe crane jib is raised or lowered by moving the control handle backwards or forwards respectively. Harbin Engineering UniversityThe spee

28、d at which the jib is raised or lowered is proportional to the distance the handle is moved. Harbin Engineering UniversityChanges in speed are effected by changing the pressure of the oil that is supplied to the control cylinder and which regulates the pump by means of a servomotor(伺服电动机马达). Harbin

29、Engineering UniversityThis changes the oil flow and thus the speed of the rotor in the hydraulic motor. Harbin Engineering UniversityThe safety system consists of: a main safety valve; two pressure reducing valves. Harbin Engineering UniversityThe slewing winch, which is almost identical to luffing

30、winch, is controlled by using the same handle as that used for the luffing winch. Harbin Engineering UniversityA small movement of the control handle to the right or left gives rise to oil pressure in the brake cylinder and releases the brake on the slewing winch. Harbin Engineering UniversityMoveme

31、nt of the control handle to the right or left in excess ofthe positions that release the brake starts the crane moving to the right or left respectively. Harbin Engineering UniversityThe closed hydraulic system consists of an axial piston pump with variable output and a hydraulic motor mutually conn

32、ected through oil pressure lines. Harbin Engineering UniversityThe amount of oil flowing through the system and the direction of flow are regulated by means of a servomotor. Harbin Engineering UniversityWhen in operation, it is unavoidable that a small amount of oil escapes through leakage, and in o

33、rder to compensate for these leaks the system is connected to a feed pump. Harbin Engineering UniversityFor pumping up, two check valves are used, and a bypass valve limits the pressure to 17-25 bar. Harbin Engineering UniversityThe safety system is designed for a certain maximum pressure, and the w

34、orking pressure must therefore be limited. Harbin Engineering UniversityFor this reason there is included a main relief valve that connects the pressure side of the system to its suction side if the permissible pressure is exceeded. Harbin Engineering UniversityA double check valve with a common spr

35、ing ensures that the relief valve always operates, regardless of which of the oil lines is the pressure side. Harbin Engineering UniversityReading materialsMooring equipment(系泊，系缆设备)Harbin Engineering UniversityWinches with various arrangements of barrels are the usual mooring equipment used on boar

36、d ships. Harbin Engineering UniversityIt usually consists of a driving motor, a reduction gear, a winch barrel or drum and one or two warp ends. Harbin Engineering UniversityThe winch barrel or drum is used for hauling in(拖) or letting out(放) the wires or ropes which will fasten the ship to the shor

37、e. Harbin Engineering UniversityThe warp end is used when moving the ship using ropes or wires fastened to bollards(系船柱) ashore and wrapped around the warp end of the winch.Harbin Engineering UniversityThe motor drive is passed through a spur gear transmission, a clutch(离合器) and thus to the drum and

38、 warp end. Harbin Engineering UniversityA substantial frame supports the assembly and a band brake is used to hold the drum when required. Harbin Engineering UniversityThe control arrangements for the drive motor permit forward or reverse rotation together with a selection of speeds during operation

39、.Harbin Engineering UniversityMooring Winch Mooring winches provide the facility for tensioning(拉紧, 使紧张) the wire up to the stalling capacity of the winch, usually 1.5 times full load, Harbin Engineering Universitythereafter the load is held by the prime mover brake or barrel brake when the power is

40、 shut off. Harbin Engineering University The winch cannot pay out wire unless the brake is overhauled or recover wire unless manually operated, thus wires may e slack. Harbin Engineering UniversityAutomatic mooring winches provide the manual control previously described but in addition incorporate c

41、ontrol features such that, Harbin Engineering Universityin the automatic setting, the winch may be overhauled and wire is paid off the barrel at a pre-determined maximum tension; Harbin Engineering Universityalso wire is recovered at a lower tension should it tend to e slack(松弛). Harbin Engineering

42、UniversityThus there is a certain range of tension, associated with each step of automatic control, when the wire is stationary. Harbin Engineering UniversityIt is not practical to reduce this range to the minimum possible as this result in hunting(振荡，不稳定) of the controls. Harbin Engineering Univers

43、ity It should be noted that the principal reason for incorporating automatic controls with the features described is to limit the render(绞上，拖) value of the winch and avoid broken wires; Harbin Engineering Universityalso to prevent mooring wires from ing slack. Harbin Engineering UniversityLoad sensi

44、ng devices are used with automatic mooring winches, e.g. spring-load gearwheels and torsion bars are widely used with steam and electric winches; Harbin Engineering Universityfluid pressure sensing either steam or hydraulic oil pressure, is also used where appropriate. Harbin Engineering UniversityT

45、he majority of automatic mooring winches are spur geared to improve the backward efficiency of the gear train(齿轮系) for rendering, Harbin Engineering Universitythe gearing and bearings being totally enclosed and lubricated from the oil sump. Harbin Engineering UniversityOn larger mooring winches wher

46、e a barrel brake is fitted, it is now common practice to design the brake to withstand the breaking strength(断裂强度或负荷) of the mooring wire. Harbin Engineering UniversityWorm geared (蜗杆传动的) automatic mooring winches are mon as the multi-start(多头) feature required to improved gear efficiency reduces th

47、e advantage of worm gear i.e. the high gear ratio. Harbin Engineering UniversityB. Anchor handling equipment(抛锚设备)Harbin Engineering UniversityThe windlass(锚机) is the usual anchor handling device where one machine may be used to handle both anchors. Harbin Engineering UniversityA more recent develop

48、ment, particularly on larger vessels, is the split(分离的) windlass where one machine is used for each anchor.Harbin Engineering UniversityChain or cable lockerSpurling pipeCable lifterAnchorHarbin Engineering UniversityThe rotating units of a split windlass consist of a cable lifter(锚链轮) with shaped s

49、nug(凸起) to grip the anchor cable, Harbin Engineering Universitya mooring drum for paying out or letting go of mooring wires and a warp end for warping duties. Harbin Engineering UniversityEach of these unites may be separately engaged or disengaged by means of a dog clutch(爪形离合器), although the warp

50、end is often driven in association with the mooring drum.Harbin Engineering UniversityA spur gear assembly transmits the motor drive to the shaft where the various dog clutches enable the power take-off.Harbin Engineering UniversitySeparate band brakes are fitted to hold the cable lifter and the moo

51、ring drum when the power is switched off.Harbin Engineering UniversityThe cable lifter unit is mounted so as to raise and lower the cable from the spurling pipe(锚链管), which is at the top and center of the chain or cable locker(锚链舱).Harbin Engineering UniversityAnchor capstans(起锚绞盘) are used in some

52、installations where the cable lifter rotates about a vertical axis. Harbin Engineering UniversityOnly the cable lifter unit is located on deck, the driving machinery being on the deck below.Harbin Engineering UniversityC. Preliminaries(准备工作) for operating the hydraulic deck machineryHarbin Engineeri

53、ng UniversityFilling the deck machinery with oil Oil specially made for operation of hydraulic pump, hydraulic motor and hydraulic equipment should be used.Harbin Engineering UniversityIn case such oil is not available, turbine oil of a good quality may be used. Harbin Engineering UniversityUse of water, light oil, heavy oil, animal or vegetable oil and also ordinary machine oil is strictly prohibited.Harbin Engineeri