A condenser throat structure with bypass function

Abstract

The present invention relates to a condenser throat structure with a bypass exhaust function, including a condenser throat shell, wherein one end of the condenser throat shell is provided with an exhaust steam exhaust port, and the upper side is provided with a bypass exhaust port, and a guide orifice plate is installed between the exhaust steam exhaust port and the bypass exhaust port. The guide orifice plate is parallel to the lower plate of the condenser throat shell. The condenser throat structure of the present invention is simple and does not occupy additional space compared with the traditional structure. The fixation of the pressure reducing device and the shell with welding is changed to a bolt connection, which reduces the possibility of vacuum damage caused by leakage of the condenser, and after the guide orifice plate is used to separate most of the bypass steam flow from the exhaust steam flow, the exhaust steam and the bypass steam body no longer affect each other. The orifice plate design reduces the impact force of the bypass steam flow on the guide orifice plate, which is beneficial to increase the structural strength of the guide orifice plate and the stability during operation.

Description

Technical Field

[0001] The invention relates to a condenser for a marine steam turbine, in particular to a throat structure of the condenser. Background Art

[0002] In a marine environment, the output conditions of steam turbines change frequently, and the steam consumption varies greatly between conditions. However, the total amount of steam consumed by the system requires the turbine to change less when the turbine changes its condition. Therefore, a bypass system is required to absorb excess working steam when the turbine is running at low power or shut down. Therefore, the bypass system is an indispensable structure in a marine steam turbine system.

[0003] The side discharge structure is composed of multiple parts, generally consisting of a pressure reducing structure, a temperature reducing structure, and a connection structure at the throat of the condenser.

[0004] At present, the bypass structure of the condenser throat mostly adopts the plug-in structure. Figure 1 shown.

[0005] The plug-in structure directly inserts the bypass pipe into the throat of the condenser, and then welds the bypass pipe to the throat shell. When the structure is in operation, the bypass steam is discharged into the throat of the condenser through the plug-in structure, and then enters the condenser to exchange heat with the cooling water.

[0006] In this structure, the intubation pipe is installed in the middle of the throat of the condenser. When the turbine is operating normally, the exhaust steam must bypass the bypass intubation pipe before it can enter the condenser to exchange heat with the cooling water. This will cause a certain pressure loss. And this structure has certain risks when the bypass structure is used synchronously when the turbine is running. The accumulation of high-pressure steam generated by the bypass mechanism in the throat can also easily increase the steam pressure in the throat of the condenser, thereby causing the back pressure of the turbine to increase and ultimately causing the overall output power of the turbine to decrease.

[0007] There are also certain risks in welding the connection between the insert structure and the throat shell of the condenser. The high-speed steam flow passing through the bypass pipe during use can easily cause pipeline vibration and other phenomena. After long-term use, the welding position between the insert structure and the throat shell is likely to loosen, resulting in gaps, and outside air rushing into the condenser. Ultimately, the vacuum inside the condenser is destroyed and the output power of the steam turbine decreases. Summary of the invention

[0008] In order to improve the flow state of the bypass structure of the condenser throat, the present invention proposes a condenser throat structure with a bypass function.

[0009] To achieve the above-mentioned purpose, the technical solution of the present invention is: a condenser throat structure with a bypass exhaust function, comprising a condenser throat shell, one end of the condenser throat shell is provided with a waste steam exhaust port, the upper side is provided with a bypass exhaust port, and a guide orifice plate is installed between the waste steam exhaust port and the bypass exhaust port.

[0010] Furthermore, the guide orifice plate is parallel to the lower plate of the throat shell of the condenser.

[0011] Furthermore, a plurality of support plates are installed between the guide hole plate and the upper plate of the condenser throat shell.

[0012] Furthermore, the support plate is connected to the guide hole plate and the upper plate of the condenser throat shell by welding.

[0013] Furthermore, the connection position between the guide hole plate and the throat shell of the condenser is fixed by welding.

[0014] Furthermore, the cold exhaust steam discharge port is connected to the exhaust cylinder of the steam turbine by means of bolt connection, so as to receive the exhaust steam discharged from the steam turbine in the axial direction.

[0015] Furthermore, the bypass discharge port is connected to the pressure reducing device by means of bolt connection, and is used to vertically receive the bypass steam discharged from the bypass device on the upper side of the throat shell of the condenser.

[0016] The beneficial effects of the present invention are:

[0017] The throat structure of the condenser of the present invention is simple and does not occupy additional space compared with the traditional structure. The fixing of the pressure reducing device to the shell is changed from welding to bolt connection, which reduces the possibility of vacuum damage caused by leakage of the condenser. After the guide orifice plate is used to separate most of the bypass steam flow from the exhaust steam flow, the exhaust steam and the bypass steam body no longer affect each other. The orifice plate design reduces the impact force of the bypass steam flow on the guide orifice plate, which is beneficial to increase the structural strength of the guide orifice plate and the stability during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram of the existing intubation structure;

[0019] Figure 2 It is a front view of the throat structure of the condenser of the present invention;

[0020] Figure 3 for Figure 2 Left sectional view of

[0021] Figure 4 This is a schematic diagram of the main steam valve stem application example;

[0022] Among them: (a) the steam turbine is running at full load, (b) the steam turbine is bypassed when it is shut down, and (c) the steam turbine is bypassed at the same time when it is running at low load. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] A new condenser throat structure of the present invention. The structure consists of a guide hole plate 1, a support plate 2, and a condenser throat shell 3. The assembly positions of each part are detailed in Figure 2 , as shown in 3.

[0025] A waste steam discharge port A is provided at one end of the throat shell 3 of the condenser, and a bypass discharge port B is provided on the upper side. The waste steam discharge port receives the waste steam discharged from the steam turbine axially, and is connected to the exhaust cylinder of the steam turbine by bolt connection. The bypass discharge port receives the bypass steam discharged from the bypass structure vertically on the upper side of the throat, and is connected to the pressure reducing device by bolt connection. A guide orifice plate 1 is installed between the waste steam discharge port and the bypass discharge port. The guide orifice plate 1 is parallel to the lower plate of the condenser throat shell 3; a plurality of support plates 2 are installed between the guide orifice plate 1 and the upper plate of the condenser throat shell 3, and the support plate 2 is connected to the guide orifice plate 1 and the upper plate of the condenser throat shell 3 by welding, and the connection position of the guide orifice plate 1 and the condenser throat shell 3 is also fixed by welding.

[0026] During installation, the upper plate of the condenser throat shell 3 and the support plate 2 are welded first, and then the support plate 2 and the guide orifice plate 1 are welded. Then the welding stress relief and post-weld machining of the welded assembly are performed. After that, the upper plate of the condenser throat shell 3 is welded to the remaining plates of the condenser. The installation steps between the condenser throat and the condenser are the same as those of the ordinary condenser.

[0027] Figure 4 The operation of the condenser throat under various working conditions is shown in Figure 2.

[0028] Figure 4 (a) shows the throat flow when the bypass pipe is closed when the turbine is running at full load. After the exhaust steam enters the condenser, part of the steam enters the upper side of the guide orifice plate through the holes on the guide orifice plate, so that the steam fills the entire condenser throat chamber, and the condensation tube bundle area on the rear side of the throat chamber can evenly contact the exhaust steam.

[0029] Figure 4 (b) shows the flow in the throat when the turbine is shut down and bypassing. After the bypass steam enters the throat, part of the bypass steam flows into the lower side of the throat through the holes on the guide orifice plate, while most of the bypass steam flows into the condensation tube bundle area along the guide orifice plate.

[0030] Figure 4 (c) in the figure shows the throat flow of the steam turbine when it is in low power state and with small flow bypass. A part of the bypass steam enters the lower part of the throat through the holes on the guide orifice plate. Since the steam volume is small, it will not affect the exhaust steam discharge. Therefore, the back pressure and output power of the steam turbine can be guaranteed.

Claims

1. A condenser throat structure with a bypass function, comprising a condenser throat shell, characterized in that: A waste steam discharge port is provided at one end of the condenser throat shell, and a bypass discharge port is provided on the upper side, and a guide orifice plate is installed between the waste steam discharge port and the bypass discharge port; the guide orifice plate is parallel to the lower plate of the condenser throat shell; a plurality of support plates are installed between the guide orifice plate and the upper plate of the condenser throat shell; the support plate is connected to the guide orifice plate and the upper plate of the condenser throat shell by welding; the connection position of the guide orifice plate and the condenser throat shell is fixed by welding.

2. The condenser throat structure with bypass function according to claim 1, characterized in that: The exhaust steam discharge port is connected to the exhaust cylinder of the steam turbine by bolt connection, and is used to receive the exhaust steam discharged from the steam turbine in the axial direction.

3. The condenser throat structure with bypass function according to claim 1, characterized in that: The bypass discharge port is connected to the pressure reducing device by bolt connection, and is used to vertically receive the bypass steam discharged from the bypass device on the upper side of the throat shell of the condenser.

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