CN114837758A

CN114837758A - Method for mounting last-stage blade vibration monitoring sensor for nuclear turbine

Info

Publication number: CN114837758A
Application number: CN202210386141.6A
Authority: CN
Inventors: 冯振; 李念光; 方立彪
Original assignee: Nanjing Foi Measurement And Control Technology Co ltd
Current assignee: Nanjing Foi Measurement And Control Technology Co ltd
Priority date: 2022-04-13
Filing date: 2022-04-13
Publication date: 2022-08-02

Abstract

The invention belongs to the field of blade vibration monitoring in the operating state of a steam turbine. The installation of the sensor of the last stage blade of the nuclear power turbine is a difficult problem of a blade vibration monitoring system, and not only the fixing mode of a sensor probe is considered, but also the fixing of a sensor cable and how to discharge the sensor cable out of a cylinder body are considered. In order to solve the problem, the invention designs a method for mounting a last-stage blade vibration monitoring sensor of a nuclear turbine. The design adopts a thread installation mode to install the sensor probe on the partition plate of the low-pressure cylinder of the steam turbine, and the sensor lead-out wire is fixed at the position of the cylinder body in the low-pressure cylinder in a way of riding a horse card and adding screws. All sensor cables were collected together at the mid-section of the low pressure cylinder and all of them were introduced into a bent copper tube. In order to prevent the sensor cable from being detached easily when the cylinder is opened during the maintenance of the steam turbine, the sensor cable is provided with a disconnectable cable plug. After the copper pipe penetrates out of the outer cylinder body of the low-pressure cylinder of the steam turbine, each cable in the copper pipe is sealed by a metal flange head so as to meet the sealing requirement of the steam turbine. The invention consists of four parts: the sensor comprises a sensor probe, a sensor cable, a sensor connecting wire cable plug and a sensor extending wire, wherein the sensor probe is installed in a mode that 2 the sensor cable is fixed on a cylinder body, 4 the sensor extending wire is sealed after being transmitted out of an outer cylinder.

Description

Method for mounting last-stage blade vibration monitoring sensor for nuclear turbine

Technical Field

The invention relates to a mounting mode of a blade sensor of a blade vibration monitoring system.

Background

The turbine moving blade is a key part for the operation of the turbine, and bears the high-speed impact of airflow while keeping high-speed rotation for a long time, and particularly, the operating condition of the turbine low-pressure final-stage moving blade is severe. When a crack is generated in the operation process of the low-pressure last-stage moving blade and the crack is generated after the crack is expanded to the blade, the unit is forced to stop, and then the great economic loss is caused, so that the monitoring of the operation condition of the low-pressure last-stage blade of the steam turbine is very important. Under general conditions, the operation condition of the turbine blade can be well reflected by monitoring the vibration of the turbine blade. In recent years, the on-line monitoring of the vibration of the turbine blade is more and more emphasized in China, and the installation and the development of a turbine vibration monitoring system are also greatly promoted. The blade sensor is used as a first component of a turbine blade vibration monitoring system, and the installation of a blade sensor probe and the cylinder penetrating fixation of a cable are always difficult problems. The problem is solved, and the method is a necessary condition for installing the turbine blade vibration monitoring system and also a preposed requirement for the operation of the turbine blade vibration monitoring system.

Disclosure of Invention

The invention aims to solve the problems of the installation mode of a blade sensor probe in a turbine blade vibration monitoring system, the fixation of a sensor cable on a cylinder body and the sealing of the sensor cable penetrating out of the cylinder body.

The purpose of the invention is realized by the following technical scheme:

1. installation mode of the sensor probe: the sensor probe shells were uniformly 90mm in length, 30mm in diameter and M30 x 2 in thread. And drilling and tapping at the last stage blade partition plate of the low-pressure cylinder of the steam turbine, wherein the thread is M30 x 2, and the sensor probe is installed at the designated position of the blade partition plate of the steam turbine in a thread mode. And to gather the sensor outlets together.

2. Fixing of the sensor cable: according to the installation position of the sensor probe, outgoing lines at the tail part of the sensor probe are respectively gathered together and are respectively arranged into an upper group and a lower group, sensor cables of the upper group and the lower group are respectively arranged into a layer and are tiled on the outer wall of an inner cylinder body of a low-pressure cylinder of the steam turbine, and the sensor cables are fixed on the inner cylinder body of the low-pressure cylinder through a horseback and screws.

3. A sensor cable joint: collect all sensor cables on the inner casing of steam turbine low pressure jar, make the cable joint of sensor be located the mid-plane department of low pressure jar to install water joint on the cable joint and protect, prevent that water from getting into to connect the department and leading to haring sensor signal transmission.

4. Preparing a bent copper pipe, punching at a proper position of an outer cylinder of a low-pressure cylinder of a steam turbine, penetrating the copper pipe out of the outer cylinder, sealing the copper pipe and the copper pipe at the position where the copper pipe penetrates out of the outer cylinder of the low-pressure cylinder by a welding method, manufacturing a metal seal at the outlet of the copper pipe, forming a through hole in the metal seal, mounting a metal gland head on each through hole, welding the metal seal at the outlet of the copper pipe, penetrating a sensor cable out of the cylinder body through the metal gland heads on the through holes, and sealing the part of the sensor cable penetrating out of the cylinder body by using the metal gland heads.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the sensor probe is convenient and quick to install, and does not need an additional fixing tool.

(2) The cable is fixed firmly, has the metal armor protection moreover, the condition of cable wearing and tearing can not appear.

(3) The low-pressure cylinder split surface is provided with the disconnectable cable joint, so that the sensor probe at the upper end is not required to be detached when the cylinder is opened to overhaul the steam turbine, and the cable joint is only required to be disconnected.

(4) The sensor cable is collected in the copper pipe, the outlet of the copper pipe is sealed in a metal welding mode, a through hole is formed in the metal seal, a metal flange head is installed at the through hole, the sensor cable is sealed through the metal flange head, and the sealing performance of the steam turbine cylinder body is guaranteed.

Drawings

Fig. 1 is a general view of a sensor mounting manner.

Fig. 2 shows a sensor mounting method.

FIG. 3 is a schematic view of a sensor cable interface.

Fig. 4 is a sensor cable cylinder fixing diagram.

FIG. 5 is a sensor cable seal diagram.

Detailed Description

The invention aims to solve the problems that in the installation of a turbine blade monitoring system, the installation mode of a blade sensor probe is complex and changeable, a sensor cable is difficult to fix and protect, the cylinder outlet position of the sensor cable is difficult to seal, and the like. Embodiments are further described below with reference to the accompanying drawings.

As shown in figure 1, the sensor probes are arranged on the upper side and the lower side of a last-stage blade partition plate of the low-pressure cylinder, a group of sensor probes are arranged on the upper side of the last-stage blade partition plate of the low-pressure cylinder, and a group of sensor probes are arranged on the lower side of the last-stage blade partition plate of the low-pressure cylinder. On the upper side of the last-stage blade partition plate, the sensor probes are symmetrically arranged, and the installation interval of every two sensor probes is 10 degrees. Sensor probes on the lower side of the last-stage blade partition plate are installed from seven o 'clock directions to eight o' clock directions, and every two sensor probes are also spaced by 10 degrees. The sensor probe is installed by drilling and tapping on the last-stage blade partition plate (8) of the low-pressure cylinder, and the installation thread is M30 x 2. The shell (9) of the sensor probe is 90mm in uniform length, 30mm in diameter and provided with M30 x 2 threads, and the shell of the sensor probe is screwed into the mounting hole formed in the last-stage blade partition plate according to the threads during mounting without mounting and fixing a tool and an additional screw.

The tail outgoing line (7) of the sensor probe is bent and attached to the inner cylinder body of the low-pressure cylinder and is fixed by a horsecard and screws. The low-pressure cylinder inner cylinder body is punched and tapped at equal intervals, the two parts are divided into a left part and a right part (24), cables of the upper half cylinder body are collected together (22), and the cables are fixed on the inner cylinder body by virtue of a riding clamp (23) and screws. The cables of the lower cylinder half are also brought together and fixed to the inner cylinder with a horsecard and screws. All sensor cables are collected on the cylinder wall in the low-pressure cylinder. And adjusting the cable position to enable the cable joint to be positioned near the middle split surface of the low-pressure cylinder. And a waterproof joint (14) is additionally arranged to protect the joint. Loosening and tightening nuts (12) at two ends of the waterproof joint are screwed, the clamping claw (13) can be contracted to seal incoming wires at two ends, and water vapor is prevented from entering. Put into crooked copper pipe (5) with all sensor extension lines behind the joint, the extension line of sensor installs metal armor protective layer additional, prevents that copper pipe kneck friction fish tail sensor cable.

After the copper pipe that is equipped with the sensor cable spreads out the outer jar, need to seal copper pipe with a metal seal of copper pipe welding, wherein install metal glan head on the metal seal and reserve the through wires mouth as the sensor cable, glan head quantity and sensor quantity need keep the same, adopt welded mode to seal the metal seal and be connected to behind the copper pipe, wear out the sensor cable again from the glan head, wear out the compelling nut (38) of glan head after the sensor line wears out the glan head and screw up, can lead to clamping jaw (36) shrink to seal the sensor cable.

Claims

1. A method for installing a last-stage blade vibration monitoring sensor for a nuclear turbine is characterized by comprising the following steps of:

the mounting mode (1,2) of the sensor probe; fixing (3) a sensor cable in a low-pressure cylinder of the steam turbine; a cable plug (4) which can be disconnected and is arranged at the position of the sensor cable, which is close to the middle split surface; the sensor cable is gathered and deeply enters the copper pipe (5); the sensor extension cable penetrates through a seal (6) at the position of the copper pipe.

2. The method of mounting a sensor probe of claim 1. The method is characterized in that: the sensor probe shell (9) is installed on a partition plate (8) of a last stage blade of the low-pressure cylinder in a threaded installation mode. The sensor probe coil part (10) does not extend out of the last stage blade diaphragm. The outgoing line (7) at the tail end of the sensor probe is provided with a metal armor protective layer.

3. The sensor cable fixation at the cylinder of claim 1, characterized in that:

the sensor cable (22) is fixed on the low-pressure cylinder inner cylinder wall (21) through a horsecard (23) and a screw (24).

4. The sensor cable breakable cable junction according to claim 1, wherein: the middle of the sensor cable (11) is provided with a cable joint (15) which can be disconnected, and a waterproof joint (14) is arranged at the joint for protection, so that the cable joint is prevented from water inflow.

5. The seal of the sensor extension cable where it exits the copper tubing of claim 1, wherein: a metal seal (31) is welded at the outlet of the copper pipe, a through hole (33) is formed in the metal seal, and a Glan head (32) is installed at the through hole to seal a sensor cable passing through the sensor cable.

6. The housing (9) of a sensor probe according to claim 2, characterized in that: the housing material was 304 stainless steel, 90mm in length, 30mm in diameter, and M30 x 2 as a thread.

7. The sensor cable (22) of claim 3, wherein: the outside of the cable is wrapped with a metal armor protective layer; the sensor cable joint (15) is a metal joint, and is pushed, pulled and self-locked and quickly pulled and inserted.

8. The horsecard (23) according to claim 3, characterized in that: flat, inner diameter size 28mm, material 304 stainless steel.

9. The watertight joint (14) according to claim 4, characterized in that: waterproof grade: IP68, having clamping grips (13) at both ends for loosening and tightening the nut (12).

10. A Glan head (32) according to claim 5, characterized in that: the material is 304 stainless steel. The wire outlet is provided with a clamping claw (36), a thread (37) and a packing nut (38), and the clamping claw, the thread (37) and the packing nut are fixed on the metal seal by utilizing nuts (35) at two ends.