JPH08201185A - Thermocouple device - Google Patents

Abstract

PURPOSE: To improve vibration strength and increase stiffness with a double structure up to thermo well and prevent steam leakage by forming a part to be inserted into the thermo well of a protection cylindrical body in one structure of a thin cylinder. CONSTITUTION: The tip of an inner cylinder 4 is inserted into a ring (h) and is welded 9a. The inside of the tip of an outer cylinder 3 is inserted into the outside of the ring (h) and is welded 9d. A ring-shaped bracing 5 with a slight clearance with the outer cylinder 3 is welded 9c to the inner cylinder 4 at a specific interval. Also, a mounting fitment 6 is inserted into the base edge part of the outer cylinder 3 and is welded 9b. Then, a thermocouple 1 is inserted until its tip comes into contact with the inner cylinder 4 and is fixed to the taper screw part via a packing 8 using a mounting bolt 7, where the thin cylinder 2, the inner cylinder 4, the outer cylinder 3, and the thermocouple 1 from a protection cylinder body, and the mounting fitment 6, the mounting bolt 7, and the packing 8 form an airtight fixing means, thus obtaining a reliable thermocouple device without any vibration during use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocouple device for detecting steam temperature in a steam turbine casing.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a conventional thermocouple device.
In FIG. 3, the inner surface of the inner casing 14 is arranged adjacent to the outer surface of the blade ring 13. A thermowell 11 is provided on the outer surface of the inner casing 14. There is an outer casing 15 that covers the inner casing 14, and the outer surface of the outer casing 15 is covered with a heat insulating material 16. The thermocouple protection cylinder 010 is inserted into the blade ring 13 from the outside of the outer casing 15 via the thermowell 11, and detects the temperature of the steam flowing in the steam turbine casing 12. Protective cylinder 010 is the outer compartment 1
It is welded to the insertion part of No. 5 by 17a. Further, the base end side protrudes from the heat insulating material 16 to enable inspection of the thermocouple 01.
The thermowell 11 is welded 17b to the inner casing 14.

FIG. 4 shows a sectional view of a conventional protective cylinder 010.
The protective cylinder 010 is formed by welding pipe materials 03 and 02 having two diameters, large and small. A plug 021 provided with a thermocouple holding hole is welded to the tip of the small diameter tube 02 inserted into the thermowell 11.

The thermocouple 01 is hermetically fixed at the end on the large diameter tube 03 side with a mounting bolt 07 via a packing 08.

[0005]

The above-mentioned conventional device has the following problems.

(1) The thermowell 11 projects into the steam flow of high temperature and high pressure, and vibrates by receiving a large steam fluid excitation force. This vibration also excites the protective cylinder 010 and the thermocouple 01. Since the protective cylinder 010 vibrates with the portion in contact with the thermowell 11 and the welded portion of the outer casing 15 of the protective casing 010 as the base point, the tip plug 021 welded portion, the outer casing 15 welded portion 17a of the large diameter pipe 03, and the large diameter pipe 03 and small-diameter pipe 02 A large stress may be generated near the joint and a crack may be generated.

(2) Since steam also flows in the space sandwiched between the outer casing 15 and the inner casing 14, if the protective cylinder 010 is damaged, the steam leaks from the thermocouple mounting portion 18 and is in a dangerous state. Become.

(3) Since the thermocouple 01 is held only by the tip plug 021 and the thermocouple mounting portion 18, it is likely to vibrate significantly, and the signal line is likely to be broken due to the vibration.

[0009]

The present invention employs the following means to solve the above-mentioned problems.

That is, as the thermocouple device, a blade ring, an inner casing having an inner surface adjacent to the outer face of the blade ring and having a thermowell for insertion on the outer face, and an outer casing covering the inner casing. , A thermocouple protective tube that is inserted from the outside of the outer casing and is inserted into the blade ring through the thermowell and welded to the outer surface of the outer casing, and the thermocouple protective casing extends to the thermowell portion. Is formed of a double cylinder, and the thermowell portion is formed of a thin cylinder having a small diameter and a closed end, and a protective cylinder body, and an outer cylinder provided at a plurality of locations of the inner cylinder of the double cylinder. An annular steady rest having a slight gap, a thermocouple inserted until the tip hits the inner cylinder, and a fixing means for hermetically holding the thermocouple at the base end of the double cylinder.

[0011]

By the above means, the portion of the protective cylinder body to be inserted into the thermowell has a thin cylinder integral structure.
Vibration strength is improved. That is, the conventional tip plug is eliminated and there is no welded portion having weak structural strength.

Further, since the thermowell has a double structure, the rigidity is remarkably increased as compared with the conventional one. Furthermore, even if a crack should occur in the outer cylinder, airtightness can be maintained in the inner cylinder,
Steam leakage is prevented.

The double cylinders come into contact with each other via the steady rests, so that each of them is not easily shaken by itself, and the vibration is suppressed.
Further, since the inner diameter is small over the entire length of the protective cylinder main body, the diameter difference from the thermocouple to be inserted is small, and the vibration of the thermocouple is suppressed.

As described above, vibration during use,
A highly reliable thermocouple device can be obtained without stress concentration.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 and 2, a, b, c and d indicate corresponding parts.

The parts described in the conventional example are designated by the same reference numerals and the description thereof will be omitted, and the parts relating to the present invention will be mainly described.

Details of the thermocouple protection cylinder 10 inserted from the outside of the outer casing 15 in FIG. 3 are shown in FIGS.

The portion starting from the thermowell 11 is formed by a thin tube 2 having a small diameter and a closed tip, and its base end portion g is expanded conically on the base end side. A coaxial projecting ring h is formed on the end face of the base end portion.

The tip of the inner cylinder 4 is inserted inside the ring h and welded 9a. The inside of the tip of the outer cylinder 3 is inserted into the outside of the ring h and welded 9d. A ring-shaped steady rest 5 having a slight clearance with the outer cylinder 3 is welded 9c to the inner cylinder 4 at a predetermined interval.

The inner cylinder 4 is slightly shorter than the outer cylinder 3, has the same inner diameter as the inner diameter of the thin cylinder 2, and has a minimum necessary diameter for inserting the thermocouple 1.

The mounting member 6 has an outer diameter substantially equal to the inner diameter of the outer cylinder 3, a stepped recess having a diameter substantially equal to the outer diameter of the inner cylinder 4, and a taper screw at the base end. The fitting 6 is inserted into the base end of the outer tube 3 and welded 9b. The thermocouple 1 is attached by inserting the thermocouple 1 into the inner cylinder 4 until its tip hits, and fixing the thermocouple 1 to the taper screw portion with a mounting bolt 7 via a packing 8.

The thin cylinder 2, the inner cylinder 4, the outer cylinder 3 and the thermocouple 1 are the protective cylinder body. Further, the mounting bracket 6, the mounting bolt 7, and the packing 8 are airtight fixing means.

The protective cylinder body is inserted from the outside of the outer casing 15 through the thermowell 11 as usual, and is welded 17a outside the outer casing 15.

With the above construction, the following operational effects can be obtained.

(1) The thin cylinder 2 at the tip of the protective cylinder body 10 that comes into contact with the thermowell 11 has an integrated structure, and the strength during vibration increases.

(2) Since the base portion of the protective cylinder main body 10 has a double structure, the rigidity is high, and even if a crack is formed in the outer cylinder 3, the inner cylinder 4 is kept airtight and vapor leakage can be prevented.

(3) The outer cylinder 3 and the inner cylinder 4 come into contact with each other through the steady rests 5, so that each of them becomes difficult to shake independently.
Vibration can be suppressed.

(4) Since the diameter difference between the inner diameter and the thermocouple 1 is small over the entire length of the protective cylinder body 10, vibration of the thermocouple 1 can be suppressed.

[0029]

As described above, the present invention has the following effects.

(1) Since the portion of the protective cylinder body to be inserted into the thermowell has an integrated structure of a thin cylinder, vibration strength is improved. That is, the conventional tip plug is eliminated and there is no welded portion having weak structural strength.

(2) Since the thermowell has a double structure, the rigidity is significantly increased as compared with the conventional one. Furthermore, even if a crack should occur in the outer cylinder, airtightness can be maintained in the inner cylinder, so vapor leakage is prevented.

(3) The double cylinders come into contact with each other through the steady rests, so that each of them is less likely to shake and vibrations are suppressed.

(4) Since the inner diameter is small over the entire length of the protective cylinder main body, the diameter difference from the thermocouple to be inserted is small,
Vibration of the thermocouple is suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermocouple protection cylinder according to an embodiment of the present invention.

FIG. 2 is a partial detailed view of FIG. 1 of the same embodiment.

FIG. 3 is an overall configuration diagram of the embodiment and a conventional example.

FIG. 4 is a sectional view of a thermocouple protection cylinder of the conventional example.

[Explanation of symbols]

 1 Thermocouple 2 Thin Cylinder 3 Outer Cylinder 4 Inner Cylinder 5 Steady Rest 6 Thermocouple Mounting Bracket 7 Mounting Bolt 8 Packing 9a, 9b, 9c, 9d, 9e Weld 10 Protective Cylinder Main Body 11 Thermowell 12 Vehicle Interior 13 Wing Ring 14 Inner compartment 15 Outer compartment 16 Heat insulation material 17a, 17b Welded portion 18 Thermocouple mounting portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeo Nishijima 9-1 Motofunamachi, Nagasaki Yamazato Sangyo Co., Ltd. Nagasaki Sales Office

Claims (1)

[Claims] 1. A vane ring, an inner casing having an inner surface adjacent to the outer face of the same and having a thermowell for insertion on the outer face, an outer casing covering the inner casing, and an outer casing of the outer casing. It has a thermocouple protection tube that is inserted from the outside and inserted into the blade ring through the thermowell and welded to the outer surface of the outer casing, and the thermocouple protection tube is a double tube up to the thermowell portion. The protective cylinder body is formed from a thin cylinder with a small diameter and a closed tip from the thermowell portion, and a small gap is provided between the inner cylinder of the double cylinder and the outer cylinder. An annular steady rest, a thermocouple inserted until the tip hits the inner cylinder, and a fixing means for hermetically holding the thermocouple at the base end of the double cylinder. Thermocouple device.