Device and method for mounting, fastening and thermal protection of high-frequency pressure sensor for inner cylinder of steam turbine

Abstract

The invention discloses a steam turbine inner cylinder-oriented high-frequency pressure sensor installation fastening and thermal protection device and method, the device comprises a shielding case and a supporting seat, and a wire hole is reserved above the shielding case and is used for leading out a cable of a high-frequency pressure sensor and monitoring real-time transmission of parameters; a stainless steel pipe is welded above the wire guide hole according to the size of a cable and is used for protecting and guiding the extending cable; a boss below the shielding cover reserves a protruding space for a protruding positioning bolt in the middle of the high-frequency pressure sensor, and upper screw holes which are evenly distributed in the circumferential direction are formed in the boss and used for being connected with the supporting base. Lower screw holes which are uniformly distributed along the circumferential direction are reserved in a boss at the upper part of the supporting seat and are used for connecting a shielding cover; the shielding cover and the supporting seat are connected in a sealed mode through screws and nuts which are evenly distributed in the circumferential direction, and the high-frequency pressure sensor is arranged in the shielding cover. According to the invention, fastening and thermal protection of the sensor body and the cable can be realized while the high-frequency pressure sensor is utilized to accurately measure the internal steam pressure of the low-pressure cylinder.

Description

Technical Field

[0001] The invention belongs to the technical field of operating status monitoring of steam turbine generator sets in power plants, and relates to a device and method for installing, fastening and thermally protecting a high-frequency pressure sensor of an inner cylinder of a steam turbine. Background Art

[0002] The operating status monitoring of the steam turbine relies on the precise measurement and real-time transmission of parameters of various sensors.

[0003] High-frequency pressure sensors are designed for rapidly changing pressure scenarios. Their operating frequency is usually between a few kilohertz and tens of kilohertz. They can be used to measure steam pressure inside turbines and provide engineers with on-site operation and maintenance references. Since these sensors are designed for fast response, their response time is usually in microseconds. This enables them to capture changes in pressure in a very short period of time, thereby providing highly timely data, usually with higher accuracy and sensitivity. For the design of high-frequency pressure sensors, lightweight and high-strength materials are usually selected, and typical threaded connection methods are adopted.

[0004] The high-flow, high-pressure steam inside the turbine is in a high-speed flow state, and the turbine cylinder is also in a state of strong vibration; therefore, the traditional threaded installation method has poor fastening properties, and fixing the sensor on the cylinder by direct welding is prone to thermal damage to the high-frequency pressure sensor. Therefore, the current conventional installation method can no longer meet the fastening and thermal protection requirements of high-frequency sensors on the inner cylinder of the turbine.

[0005] Therefore, at this stage, there is an urgent need to invent a method for installing, fastening and thermally protecting a high-frequency pressure sensor facing the inner cylinder of a steam turbine. Summary of the invention

[0006] In view of the shortcomings of existing high-frequency pressure sensors in monitoring steam pressure inside a steam turbine, the present invention provides a high-frequency pressure sensor installation, fastening and thermal protection device and method for an inner cylinder of a steam turbine.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of a steam turbine mainly comprises a shielding cover and a support seat, wherein:

[0009] A wire hole is left above the shielding cover for leading out the cable of the high-frequency pressure sensor and real-time transmission of monitoring parameters;

[0010] A stainless steel tube is welded above the wire hole according to the cable size to protect and guide the extended cable;

[0011] The boss below the shielding cover reserves a protruding space for the positioning bolt protruding in the middle of the high-frequency pressure sensor, and is provided with upper screw holes evenly distributed along the circumference for connecting the support seat;

[0012] The upper boss of the support seat is reserved with lower screw holes evenly distributed along the circumference for connecting the shielding cover;

[0013] The shielding cover and the supporting seat are sealed and connected by screws and nuts evenly arranged in the circumference, and the high-frequency pressure sensor is built therein.

[0014] A method for installing, fastening and thermally protecting a high-frequency pressure sensor facing the inner cylinder of a steam turbine using the above device comprises the following steps:

[0015] Step S1, placing the front probe of the high-frequency pressure sensor into a support seat to support the high-frequency pressure sensor;

[0016] Step S2, placing the main structure of the high-frequency pressure sensor into the shielding cover;

[0017] Step S3, the bottom support seat and the upper shielding cover are connected and fastened by screws and nuts evenly distributed in the circumference, and the built-in high-frequency pressure sensor is fully protected during welding and startup;

[0018] Step S4, welding the lower edge of the upper part of the support seat protruding to both sides to the outer side of the low-pressure inner cylinder through holes, and extending the lower probe into the inner cylinder to monitor the internal steam pressure;

[0019] Step S5, welding a stainless steel tube above the wire hole according to the cable size, one end of the stainless steel tube is connected to the shielding cover, and the other end is welded to the punching position of the low-pressure outer cylinder sensor, and the low-pressure outer cylinder is vacuum-sealed.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention can achieve fastening and thermal protection of the sensor body and cables while accurately measuring the steam pressure inside the low-pressure cylinder using a high-frequency pressure sensor;

[0022] 2. The present invention can effectively realize thermal protection of the built-in high-frequency pressure sensor during welding, fixing and startup without occupying a large space through the shielding cover and the support seat with adapted outer dimensions;

[0023] 3. The present invention connects the shielding cover and the support seat by screws and nuts, so that the device becomes an integral structure. At the same time, the support seat is welded to the outside of the low-pressure inner cylinder and a steel pipe with a wire hole is added to fasten the high-frequency pressure sensor and protect the sensor cable.

[0024] 4. The device designed by the present invention has a simple structure, the preparation materials are easy to obtain, and the processing is easy to achieve;

[0025] 5. The present invention has great universality and is easy to implement in production. Its adaptable shape and function are also applicable to other types of sensors with the same fastening and thermal protection requirements, and can be extended to other fastening and thermal protection of sensors under high temperature and high pressure conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a high-frequency pressure sensor shield;

[0027] Figure 2 It is a cross-sectional view and a top view of the high-frequency pressure sensor support seat;

[0028] Figure 3 It is a schematic diagram of the overall structural fastening of the high-frequency pressure sensor installation and thermal protection device. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0030] The present invention provides a high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of a steam turbine, the device is composed of an upper shielding cover 7 and a lower support seat 8, the shielding cover 7 and the support seat 8 are sealed and connected by four sets of screws and nuts evenly arranged in the circumference, and the high-frequency pressure sensor is built therein;

[0031] The size of the shielding cover 7 needs to be adapted to the size and shape of the high-frequency pressure sensor. A wire hole 1 is reserved above the shielding cover 7 for leading out the cable of the high-frequency pressure sensor and real-time transmission of monitoring parameters; the boss below the shielding cover 7 reserves a protruding space for the positioning bolt 2 protruding in the middle of the high-frequency pressure sensor, and is provided with four groups of upper screw holes 3 evenly distributed along the circumference for connecting the support seat;

[0032] The size of the support seat 8 also needs to be compatible with the size and shape of the high-frequency pressure sensor. The diameter of the upper boss of the support seat 8 needs to be compatible with the size of the boss below the shielding cover, and four groups of lower screw holes 4 are evenly distributed. The inner diameter of the lower screw hole 4 can be slightly smaller than that of the upper screw hole 3, which is convenient for upper and lower buckling and centering bolting. At the same time, the margin of the screw hole diameter will also reserve space between the shielding cover 8 and the screw, effectively reducing the heat conduction of high-temperature steam;

[0033] The lower edge 5 of the upper boss of the support seat 8 is chamfered to facilitate welding with the outer side of the inner cylinder of the low-pressure cylinder, thus playing a role in fixing the integrated device;

[0034] The shielding cover 7 and the support seat 8 are both cylindrical and made of SUS304 stainless steel, forming a complete side surface outside the high-frequency pressure sensor. The melting point of the shell is higher than the welding temperature of the sensor, which can achieve thermal protection for the built-in high-frequency pressure sensor during welding and fixing. At the same time, 304 stainless steel can also prevent steam corrosion;

[0035] A stainless steel tube is welded above the wire hole 1 according to the size of the cable to protect and guide the extended cable;

[0036] One end of the stainless steel tube is connected to the top of the shielding cover, and the other end is welded to the punching position of the low-pressure outer cylinder sensor, and is vacuum-sealed at the low-pressure outer cylinder.

[0037] The present invention provides a method for installing, fastening and thermally protecting a high-frequency pressure sensor facing the inner cylinder of a steam turbine using the above-mentioned device. First, the high-frequency pressure sensor is placed inside a shielding cover and a support seat, and screwed together from top to bottom. During welding, fixing and starting the machine, thermal protection of the high-frequency pressure sensor is achieved. Then, considering the structure of the inner cylinder, the high-frequency pressure sensor is welded together with the protective device on the cylinder by welding to achieve installation and fastening of the high-frequency pressure sensor. At the same time, a wire hole is reserved at the top of the shielding cover to facilitate the lead-out of the cable. The changes in the internal steam pressure can be displayed remotely in real time through the DCS system, which is convenient for operation and maintenance personnel to monitor. The specific implementation steps are as follows:

[0038] Step S1, place the front probe of the high-frequency pressure sensor into the support seat to support the high-frequency pressure sensor. The lower diameter of the support seat is adapted to the probe size, and the upper diameter is slightly larger to provide screw hole space for connecting the shielding cover.

[0039] Step S2: Place the main structure of the high-frequency pressure sensor into a shielding cover. The shape and size of the shielding cover must be adapted to the high-frequency pressure sensor, and a space is reserved at the bottom for the positioning bolts protruding from the middle of the high-frequency pressure sensor.

[0040] Step S3, the bottom support seat and the upper shielding cover are connected and fastened by 4 sets of screws and nuts evenly distributed circumferentially to form a complete side surface on the outside, so as to achieve comprehensive protection for the built-in high-frequency pressure sensor during welding, fixing and startup.

[0041] Step S4, welding the lower edge of the upper part of the support seat protruding to both sides to the outer side of the low-pressure inner cylinder through holes, and extending the lower probe into the inner cylinder to monitor the internal steam pressure;

[0042] Step S5, weld a stainless steel tube above the wire hole according to the cable size, one end of the stainless steel tube is connected to the shielding cover, and the other end is welded to the punching position of the low-pressure outer cylinder sensor, and the low-pressure outer cylinder vacuum transfer seal is applied. If the data transmission of the high-frequency pressure sensor is normal during the startup process, it means that the entire device has achieved vacuum and can isolate high-temperature steam.

Claims

1. A high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of a steam turbine, characterized in that The device comprises a shielding cover and a supporting seat, wherein: A wire hole is left above the shielding cover for leading out the cable of the high-frequency pressure sensor and real-time transmission of monitoring parameters; A stainless steel tube is welded above the wire hole according to the cable size to protect and guide the extended cable; The boss below the shielding cover reserves a protruding space for the positioning bolt protruding in the middle of the high-frequency pressure sensor, and is provided with upper screw holes evenly distributed along the circumference for connecting the support seat; The upper boss of the support seat is reserved with lower screw holes evenly distributed along the circumference for connecting the shielding cover; The shielding cover and the supporting seat are sealed and connected by screws and nuts evenly arranged in the circumference, and the high-frequency pressure sensor is built therein.

2. The high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of the steam turbine according to claim 1 is characterized in that The lower edge of the upper boss of the support seat is chamfered.

3. The high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of the steam turbine according to claim 1 is characterized in that The shielding cover and the supporting seat are both cylindrical.

4. The high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of a steam turbine according to claim 1 or 3, characterized in that The shielding cover and the supporting seat are both made of SUS304 stainless steel.

5. The high-frequency pressure sensor installation, fastening and thermal protection device facing the inner cylinder of the steam turbine according to claim 1 is characterized in that One end of the stainless steel tube is connected to the top of the shielding cover, and the other end is welded to the punching position of the low-pressure outer cylinder sensor, and is vacuum-sealed at the low-pressure outer cylinder.

6. A method for installing, fastening and thermally protecting a high-frequency pressure sensor facing the inner cylinder of a steam turbine using the device according to any one of claims 1 to 5, characterized in that The method comprises the following steps: Step S1, placing the front probe of the high-frequency pressure sensor into a support seat to support the high-frequency pressure sensor; Step S2, placing the main structure of the high-frequency pressure sensor into the shielding cover; Step S3, the bottom support seat and the upper shielding cover are connected and fastened by screws and nuts evenly distributed in the circumference, and the built-in high-frequency pressure sensor is fully protected during welding and startup; Step S4, welding the lower edge of the upper part of the support seat protruding to both sides to the outer side of the low-pressure inner cylinder through holes, and extending the lower probe into the inner cylinder to monitor the internal steam pressure; Step S5, welding a stainless steel tube above the wire hole according to the cable size, one end of the stainless steel tube is connected to the shielding cover, and the other end is welded to the punching position of the low-pressure outer cylinder sensor, and the low-pressure outer cylinder is vacuum-sealed.

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