The steam discharged from the steam turbine is merged into the low-pressure steam pipe network. Generally, the distance between the steam turbine and the pipe network is relatively long. Therefore, the first consideration in the flexible design of the pipeline is to set a fixed frame or a set of limit frames at appropriate positions to prevent external The influence of the pipe on the steam turbine, thereby narrowing the scope of the complex flexible design pipeline and improving the reliability of the flexible design. The location of the fixed frame or the limit frame should ensure that the pipelines adjacent to the machine have available flexibility. The combined effect not only prevents the outer tube from exerting force on the steam turbine, but also allows the pipelines adjacent to the machine to thermally expand and displace relatively freely. Avoid generating large thrust on the machine in the limit direction.
There is a safety valve pipeline branch in front of the check valve of the exhaust steam pipeline. This pipeline is set to ensure the effective output of the steam turbine. The impact of the pipeline cannot be ignored. It should be included in the flexible analysis of the entire exhaust pipeline system. Metal bellows expansion joints can be used in special cases where the circuit is not allowed to be detoured and the pipeline is not flexible enough. In order to prevent the steam in the cylinder from leaking along the shaft end, the steam turbine is equipped with a steam seal system. A small amount of leaked steam is discharged into the steam cooler along the steam seal pipe. The temperature of the steam seal pipe is not high, and the diameter of the pipe is not very large, so its flexibility problem is easily overlooked. Its temperature is generally below 150, sometimes it can reach 220, and the diameter is generally not greater than DN200mm. Facts have shown that if it is not well designed, it will still cause serious consequences for the turbine legs to rise, so the consideration of its flexibility is an indispensable link in the flexible design of the entire steam turbine pipeline.
The support includes brackets, hangers and various limit brackets. Setting an effective form of support at an appropriate location can not only prevent the steam turbine from bearing the weight of the pipeline, but also change the force and displacement distribution according to expectations and expectations, and effectively use the flexibility of the existing pipeline to reduce the force and torque of the pipeline on the steam turbine. The support on the steam turbine pipeline can be roughly divided into two categories, one is the load-bearing frame used to support the weight of the pipeline, which is divided into a rigid support hanger that does not allow the thermal displacement of the pipeline downward and a spring support hanger that allows the thermal displacement of the pipeline ; The other is the limit frame used to limit the horizontal displacement of the pipeline and block the horizontal thrust. The horizontal pipeline in front of the steam turbine has a downward displacement, so the support hanger on the pipeline supporting the weight of the pipeline should be a spring support hanger, and its horizontal distance from the turbine nozzle should not be too long, otherwise the riser will fall or The skew tendency will cause the machine flange and the pipeline flange to be out of parallel and misaligned during the pipeline installation inspection.
Changxing Mingwang Rubber & Plastic Technologies Co.,Ltd. , https://www.cxmingwang.com