Created on:2021-08-02 10:03

Hydraulic fault diagnosis and maintenance of hydropower equipment_ Inspection and analysis of hydraulic failure of hoist

水电设备液压故障诊断与维修_ 启闭机液压故障检查分析
Hydraulic fault diagnosis and maintenance of hydropower equipment_ Inspection and analysis of hydraulic failure of hoist

某水电站挡水建筑物为碾压混凝土拱坝,坝顶布置有4孔溢洪道,其工作弧门分别由4台2×80t液压启闭机驱动;冲砂底孔工作弧门的液压启闭机为1×63t。启闭机机房和控制室位于坝顶。
The water retaining structure of a hydropower station is a RCC arch dam. There are four spillways on the top of the dam, and the working radial gates are composed of four sets and two gates × 80t hydraulic hoist drive; The hydraulic hoist of the working radial gate of the bottom flushing hole is 1 × 63t。 The hoist room and control room are located on the dam crest.

(1)液压启闭机现状
(1) Present situation of hydraulic hoist

    每台启闭机均有各自独立的启闭液压缸、控制阀组及电气控制部分。表孔液压启闭机由液压站(表孔1、4号闸门和2、4号闸门为2台启闭机共用一液压站)、控制阀组、2只80t启闭液压缸及电气控制机构等部分组成;底孔液压启闭机有独立的液压站、控制阀组和电气控制系统。液压站电机液压泵总成为一备一用;控制阀组采用两位插装换向阀。
Each hoist has its own independent hydraulic cylinder, control valve group and electrical control part. The surface hole hydraulic hoist is composed of hydraulic station (No.1 and No.4 gates and No.2 and No.4 gates share one hydraulic station), control valve group, two 80t hydraulic cylinders and electrical control mechanism; The bottom hole hydraulic hoist has independent hydraulic station, control valve group and electrical control system. Hydraulic station motor hydraulic pump assembly is one for standby and one for use; The control valve group adopts two position cartridge directional valve.

    启闭机均未设专用液压锁定单元,利用两位插装换向阀组兼作液压锁。该方案在启闭机运行初期较为有效,但使用一段时间和一定次数后,插装换向阀组锁定效果降低,启闭机启升闸门至工作高位后,闸门因自重而下滑;另外,插装换向阀组安装在控制室,当闸门被举升至工作高位后,从液压缸至换向控制阀组的管道(最长回路约50m) 一直处于高压状态,如果管路损坏,液压缸的有杆下腔泄漏,闸门会在自重作用下快速关闭,无法控制。
There is no special hydraulic locking unit for the hoist, and the two position cartridge directional valve group is used as the hydraulic lock. The scheme is more effective in the initial stage of the operation of the hoist, but after a period of time and a certain number of times, the locking effect of the cartridge directional valve group is reduced, and the gate slides down due to its own weight after the hoist lifts the gate to the working high position; In addition, the cartridge directional valve group is installed in the control room. When the gate is lifted to the working high position, the pipeline from the hydraulic cylinder to the directional control valve group (the longest circuit is about 50m) is always in a high pressure state. If the pipeline is damaged and the lower chamber of the hydraulic cylinder is leaking, the gate will close quickly under the self weight and cannot be controlled.

    在汛期泄洪中的闸门是不允许出现这种意外的,因此必须增设液压缸锁定单元。另外,启闭机两液压缸同步控制为手动,属早期产品。
In flood season, this kind of accident is not allowed in the sluice gate, so the locking unit of hydraulic cylinder must be added. In addition, the synchronous control of the two hydraulic cylinders of the hoist is manual, which is an early product.

(2)启闭机故障表现及检查情况
(2) Hoist fault performance and inspection

    ①故障表现启闭机能正常开启、关闭闸门,但提升闸门至工作高位后不能锁定,各闸门不同程度地存在下滑量偏大的问题。24h下滑量普遍大于1m,最大下滑量达2.4m,严重超标。
① The fault shows that the hoist can open and close the gate normally, but the gate can not be locked after lifting to the working high position, and the sliding amount of each gate is too large to some extent. The 24-hour sliding amount is generally more than 1 m, and the maximum sliding amount is 2.4 m, which seriously exceeds the standard.

    ②故障检查仔细检查启闭机外观、液压缸、阀组和管网,均未发现肉眼可观测到的外漏油现象。解体液压缸检查时,发现液压缸活塞密封环都不同程度地存在磨损、翻边、卷曲、缺边、断裂等损伤,无一完好,特别是底孔启闭机液压缸活塞密封环呈完全粉碎性老化破坏;各液压缸支承环均存在一定磨损,部分支承环尺寸超差,最大间隙达0.75mm;各液压缸缸筒内壁有不同程度拉伤,拉伤部位均分布在液压缸工作位置缸筒下方,有一定规律,最为严重的是在长约6m、宽约10cm范围内有明显分散型拉痕;液压缸缸内尾部有一定程度锈蚀;两位插装换向阀阀芯密封锥面有一定磨损环痕。
② Fault inspection: carefully check the appearance of the hoist, hydraulic cylinder, valve group and pipe network, and no visible external oil leakage is found. When the hydraulic cylinder was disassembled for inspection, it was found that the piston seal rings of the hydraulic cylinder were worn, flanged, curled, missing edge and broken to varying degrees, and none of them were in good condition, especially the piston seal rings of the hydraulic cylinder of the bottom hole hoist were completely crushed and aged; The bearing rings of each hydraulic cylinder are worn to a certain extent, some of them are out of tolerance, and the maximum clearance is 0.75mm; There are different degrees of strain on the inner wall of each hydraulic cylinder, and the strain parts are distributed under the working position of the hydraulic cylinder, with a certain regularity. The most serious is that there are obvious scattered strain marks in the range of about 6m in length and about 10cm in width; The rear part of the hydraulic cylinder is corroded to a certain extent; There is a certain wear ring mark on the sealing cone of the spool of the two position cartridge directional valve.

(3)启闭机故障原因分析
(3) Failure analysis of hoist

    启闭机能正常启、闭闸门,说明控制阀组及液压站各项功能基本正常;闸门开启至工作高位后下滑量严重超标,说明启闭机液压系统存在较为严重的泄漏;无外漏油发生又说明泄漏存在于启闭机液压系统内部。根据故障现象和检查情况分析,泄漏部位在液压缸和控制阀组。
The normal opening and closing function of the gate indicates that the functions of the control valve group and the hydraulic station are basically normal; After the gate is opened to the working high position, the sliding amount seriously exceeds the standard, which indicates that there is serious leakage in the hydraulic system of the hoist; No external oil leakage occurs, which indicates that the leakage exists in the hydraulic system of the hoist. According to the analysis of fault phenomenon and inspection situation, the leakage parts are hydraulic cylinder and control valve group.

    ①液压缸内泄漏 启闭机上次大修已有5年多时间,运行时间较长及液压缸各密封环和支承结构磨损、老化、损坏,以及缸筒内壁拉伤是造成液压缸内泄的主要原因。闸门被提升并锁定于开闸工作高位后,液压系统停止工作,液压缸进出油道均被切断,有杆下腔在闸门自重作用下会产生较高压力,而无杆上腔有体积增大倾向,压力相对较低,两油腔间会形成一压力腔。当液压缸两油腔密封结构损坏时,在压力差的作用下会形成由有杆下腔向无杆上腔漏油的泄油回路;有杆下腔液压油泄漏往无杆上腔,体积减少,活塞下移,表现为闸门在自重作用下下滑。这种密封结构损坏引起的液压缸内两腔间泄漏现象即是液压缸内泄。活塞密封环损坏、缸筒内壁拉伤和活塞支承环尺寸超差,都会在液压缸内两腔间形成压力泄漏回路,产生内泄。
① It has been more than five years since the last overhaul of the hydraulic cylinder leakage hoist. The main causes of the leakage are the long running time, the wear, aging and damage of the sealing ring and supporting structure of the hydraulic cylinder, and the strain of the inner wall of the cylinder. After the gate is lifted and locked in the high position of opening, the hydraulic system stops working, the inlet and outlet oil passages of the hydraulic cylinder are cut off, and the lower chamber with rod will produce higher pressure under the self weight of the gate, while the upper chamber without rod has a tendency to increase in volume, and the pressure is relatively low, and a pressure chamber will be formed between the two oil chambers. When the sealing structure of the two oil chambers of the hydraulic cylinder is damaged, the oil leakage circuit from the lower chamber with rod to the upper chamber without rod will be formed under the action of pressure difference; The hydraulic oil in the lower chamber of the rod leaks to the upper chamber of the non rod, the volume decreases, and the piston moves down, which shows that the gate slides down under its own weight. The leakage phenomenon between the two cavities in the hydraulic cylinder caused by the damage of the sealing structure is the leakage in the hydraulic cylinder. The damage of piston sealing ring, the strain of inner wall of cylinder and the size of piston supporting ring out of tolerance will form a pressure leakage circuit between the two cavities in the hydraulic cylinder, resulting in internal leakage.

    ②系统泄漏启闭机提升闸门至工作高位后,是利用两位插装换向阀阀芯密封锥面作高位锁定。两位插装换向阀阀芯锥面多次动作后会有一定量的磨损;阀芯锥面一侧为有杆下腔压力油,另一侧为回油道,油压基本为0;在油压差的作用下:液压缸的有杆下腔高压油会通过磨损处泄漏回油箱,形成系统泄漏,使液压缸的有杆下腔体积减小,活塞下移,表现为闸门下滑。
② After the system leakage hoist lifts the gate to the working high position, the two position cartridge directional valve core sealing cone is used for high position locking. There will be a certain amount of wear after the cone of two position cartridge directional valve acts for many times; One side of the cone surface of the valve core is the pressure oil in the lower chamber of the rod, and the other side is the oil return passage, and the oil pressure is basically 0; Under the effect of oil pressure difference: the high pressure oil in the lower chamber of the hydraulic cylinder with rod will leak back to the oil tank through the wear place, forming system leakage, reducing the volume of the lower chamber of the hydraulic cylinder with rod, and moving the piston downward, which shows that the gate slides down.

    ③液压缸内泄与系统泄漏同时存在 在年久失修、下滑量较大的液压启闭机中,一般同时存在液压缸内泄和系统泄漏。本启闭机也是两种泄漏情况都存在,但以液压缸内泄漏为主,系统泄漏为辅。值得一提的是液压缸内泄和系统泄漏也存在于启门和闭门过程中,当泄漏发展到一定程度时,启闭机将无法工作。
③ Hydraulic cylinder leakage and system leakage exist at the same time in the hydraulic headstock gear which is in disrepair for a long time and has a large amount of sliding, generally there are hydraulic cylinder leakage and system leakage at the same time. There are two kinds of leakage in the hoist, but the leakage in the hydraulic cylinder is the main one, and the system leakage is the auxiliary one. It is worth mentioning that the hydraulic cylinder leakage and system leakage also exist in the process of opening and closing the door. When the leakage develops to a certain extent, the hoist will not work.

Home    Article    Hydraulic fault diagnosis and maintenance of hydropower equipment_ Inspection and analysis of hydraulic failure of hoist