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拦污格栅trash rack,设在进水口前,用于拦阻水流挟带的水草、漂木等杂物(一般称污物)的框栅式结构。
来源:拦污格栅格网制造专家作者:老张网址:http://www.chinakelan.com浏览数:897 
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  拦污格栅由边框、横隔板和栅条构成(见图,支承在混凝土墩墙上,一般用钢材制造。栅条间距视污物大小、多少和运用要求而定。水电站用的栅条间距取决于水轮机型号及尺寸,以保证通过格栅的污物不会卡在水轮机过流部件中为准。泄水隧洞和泄水孔一般不设拦污格栅,如洞径或孔径不大,而沉木较多需要设置时,栅条间距宜加大。拦污给栅所受荷载,除自重外,主要是污物堵塞后,在栅前后由于水位差形成的水荷载,一般按 2~4m水头考虑。拦污格栅的栅面尺寸决定于过栅流量和允许过栅流速。为减少水头损失和便于清污,一般要求过栅流速不大于1.0m/s左右。格栅可以做成固定的或能够起吊的。

  拦污格栅Dirt blocking grid,设在进水口前,用于拦阻水流挟带的水草、漂木等杂物(一般称污物)的框栅式结构制作标准参考图集90s503。

  拦污格栅在平面上可以布置成直线形或呈半圆的折线形,在立面上可以是直立的或倾斜的,依水流挟带污物的性质、多少、运用要求和清污方式决定。水头较高的坝后式水电站的进水口常用直立半圆形;进水闸、水工隧洞、输水管道多用直线形。

  深式进水口的拦污格栅高度与水库水位和清污方式有关。对于不需要经常清污的,其顶部高程可略高于防洪限制水位(见水库特征值);需要经常清污的,则应高于需要清污的最高水位。高度较大的拦污格栅,可做成几节,每节的尺寸可根据起吊能力确定。

  在寒冷地区的冬季,需要对拦污格栅采取防冻措施。常用的方法有:①将低压(50V)电流通到拦污格栅,利用金属结构本身的电阻发热来防冻,此法简便,但耗电量大;②在栅前水面下,利用压缩空气将水库下层温度较高的水体带到水面,维持拦污栅前后一段范围内不结冰,此法多用于大型水库。

  污物清理可用人工或清污机。人工清污适用深度较浅,一般不超过5m。当拦污栅位于水下较深时,多用清污机清污;必要时也可设置两道拦污格栅,需要清污时,先将备用拦污格栅放入检修门槽内,而后将工作拦污格栅吊出进行清理。

The dirt blocking grid is composed of a frame, a transverse partition board and a bar strip (see figure, which is supported on the wall of the concrete pier, and is generally made of steel. The distance depends on the size of dirt, how much and the application requirements. The spacing of the grid used for the hydropower station depends on the type and size of the water turbine to ensure that the dirt in the grid is not stuck in the flow passage of the turbine. Discharge tunnel and drain hole generally no trash grille, such as hole diameter or diameter is small, and the wood more need to set when the grid spacing should be increased. The load to the grid, in addition to the dead weight, mainly dirt blocking, before and after the gate due to the water level difference between the formation of water load, generally by 2 ~ 4m head. The gate size depends on the surface of the trash rack and allow a gate gate over flow velocity. In order to reduce the head loss and facilitate cleaning, the flow rate is not more than 1.0m/s. The grid can be made into a fixed or capable of lifting.

Dirt blocking grid trash grille, is arranged on the water inlet, for arresting flow with water, floating wood and other debris (generally called dirt) box gate type structure.

Trash grille in the plane can be arranged in a straight line or a zigzag semicircle, the facade can be vertical or inclined, depending on the nature and flow with how much dirt, use requirements and clean-up decisions. High head Bahou hydropower station vertical semicircular water inlet used; intake, hydraulic tunnel and water pipelines with straight line.

Deep water inlet grille height and water level of the reservoir trash and cleaning mode. For the need for frequent cleaning, the top elevation can be slightly higher than the flood control limit water level (see reservoir characteristic value); the need for regular cleaning, it should be higher than the highest water level required to clean up. High trash grille, can be made into several sections, each section size can be determined according to the lifting capacity.

In the cold area of winter, the need to take measures to stop the sewage grid. The commonly used methods are: the low voltage (50V) current to the trash grille, using resistance heating metal structure itself to antifreeze, the method is simple, but the power consumption is large; in the gate before the surface, the higher the temperature of reservoir water to the surface of compressed air, maintain no sewage gate before and after freezing range, this method is mainly used in large reservoir.

Dirt cleaning can be used for manual or cleaning machine. Manual cleaning application depth is shallow, generally not more than 5m. When the rack is located in deep water, multi- purpose cleaning machine in cleaning; if necessary, can also set up two sewage interception grille, need decontamination, first standby trash grille in gate slot, and then work to clean up trash grille hanging out.




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