YH crosshead guide wheel host damage cause crankshaft damage

YH crosshead guide wheel host damage lead to 2021 - crank shaft damage 02 - 01 basic information about the host models: MAN B& December 6 l50mc W power: 7330 kW1998 by Shanghai hudong zhonghua juki make accident after September 17, 2000, YH round 13th sailing voyage from the Netherlands to Indonesia on the Indian Ocean, 09 00, suddenly crankcase oil mist detector alarm host, the host automatically slow down. Immediately stop check, found No. 5 cylinder crank box, crosshead thrust slider fall off of the side plate; Thrust slider lateral plate 6 fixed stud all roots from the slider is cut off, thrust slider lateral plate break; Cross fixed connecting rod small end thrust block two fixed bolt pulled from the bolt head, thrust block off; Connecting rod moved forward, resulting in the connecting rod edge to take off the lead. 18, 0900, after open the connecting rod big end tile, found that the crank pin shaft neck finish, wear serious, have obvious scratch, hair and crack; On tile to take off the lead. For air floating on the sea for self-study to solve have impossible, only seal cylinder to the port of Aden in yemen recently. On September 24 arrived in Aden anchorage GOLTEN company ship shaft grinding; At the same time contact the MAN B& W company arrange the service engineer on board. GOLTEN shaft grinding work on October 19, crank pin straight neck grinding small 4. 5 mm。 Due to the local endemic, service engineer and spare parts are not to ship in time. To save on shipping date seal cylinder sailed to Colombo repair. October 30, YH arrived at the port of Colombo, GOLTEN company and MAN B& W company service engineer aboard guidance, installation and commissioning of the crew and the host other cylinder after screening, do trial voyage, on their way from Colombo to Indonesia, the normal working condition of host. The cause of the accident, YH 1 round the development of the host machine damage accident process: first, the No. 5 cylinder cross thrust slider plate fixed bolt because of stress from the roots of the side cut, then again after the crosshead fixed bolt snap of thrust block, causing displacement of the connecting rod small end. , because of the large connecting rod small end lubricated by cross oil, a connecting rod small end shift ( Ward) Cut the crank pin bearing oil, the connecting rod big end off oil, bearing axis, crank pin ablation crack. The oil temperature to produce oil and gas in No. 5 cylinder smoke detector alarm, host, automatic deceleration. 2, connecting rod big end and ovality of the crank pin exceeds bid badly. For check the measurement in the accident, found No. 5 cylinder crank pin ovality of 0. 27 mm, and the B& W specification requires less than 0. 02 mm； The connecting rod big end ovality reached 0. 28 mm, and the B& W specification requires less than 0. 03 mm。 Because of the connecting rod big end ovality and crank pin ovality, the crank pin cannot be completely fit with the crank pin. In the each stroke of the functioning of the host, connecting rod big end bearing and not smooth operation, appear to beat; Before and after the big-end bearing dynamic, connecting rod small end swing. Appear before and after the direction of the side thrust, so that the thrust force. The side thrust with the motion of the connecting rod, is an alternating force, fixed bolt is broken by the alternating stress; Before and after the cross in the up and down by the direction of force component, the thrust slider guide vane stress zhangs, make the fixed sliding vane of 6 bolts all cut off. Finally because of the crosshead pin thrust slider side panel off and moved forward, connecting rod small end thrust block off and backwards, make the oil circuit is cut off. Lead to big end off oil, holding shaft. Accident lesson YH round the accident was caused by a host to build quality is poor. Although the repair expenses shall be borne by the manufacturer, but impact greatly on ship safety operation, shipment delay benefit to suffer great losses, the company has profound lesson! 1, the new shipbuilding supervision personnel, should be the important equipment of measurement data verification, validation, seriously. To ensure that new creation quality and operation safety of the ship. 2, operating in the first two years of work on new production of ship's crew, more should be strictly in accordance with the requirements of the specification, earnestly check the maintenance of important equipment, such as the host internal check the bolts for looseness signs, to each part of the host bearing clearance inspection, etc. , so that early detection, eliminate hidden dangers, prevent accidents. （ Source: the home of Chinese seafarers)