JPH0248840B2 - DENNETSUKANPURAGUSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger tube plug device for a heat exchanger, and more particularly to a shell-and-tube heat exchanger having a downcomer pipe in the center. The present invention relates to a plug device for installing plugs in.

The heat exchanger heat transfer tube serves as a boundary between the primary fluid and the secondary fluid, and if the heat transfer tube is damaged, the two may become mixed with each other. Especially when the fluids on the primary and secondary sides are different and chemical reactions between the two become a problem, or when the
If the next side contains radioactive material, it is necessary to promptly detect the damage and form a new boundary. Possible methods for forming a new boundary include replacing the damaged heat exchanger tube with a new one, repairing the damaged portion of the heat exchanger tube, and installing plugs on the tube plate (both ends of the heat exchanger tube). In the case of large-scale equipment such as nuclear reactor plants, it is practical to perform this work with the heat exchanger left in place, but the work efficiency is extremely poor.
There is also a requirement to ensure the quality of the repaired part, and the most suitable method for repairing damaged heat exchanger tubes seems to be to install a plug in the tube sheet part.

A known technique for installing a plug in a tube sheet portion is shown in FIG. 1. A maintenance nozzle is installed in the water chamber containing the tube plate, and equipment is inserted through this nozzle to perform inspection and plugging work. This is the method used for heat exchanger tube plugs in steam generators.

Further, FIG. 2 shows an example of a published patent in which a plug is constructed using a downcomer pipe of a heat exchanger. This is most similar to the present invention, but since the heat transfer tubes are arranged in a very dense manner, a highly accurate positioning mechanism is required, but no countermeasure has been taken. is considered to be the problem.

The purpose of the present invention is to provide a heat exchanger tube plug device that, when a heat exchanger tube of a heat exchanger is damaged, approaches the tube sheet through the downcomer pipe in the center of the heat exchanger, detects the position of the damaged heat transfer, and installs a plug on the tube sheet. The object of the present invention is to provide a positioning mechanism.

A shell and tube type heat exchanger with a floating head is shown in FIG. The heat transfer tube 1 is connected to upper and lower tube sheets 2, and a secondary fluid flows inside the tube and a primary fluid flows outside the tube. When a heat exchanger tube is damaged, plugs are installed in the upper and lower tube plate portions 2 to form a new boundary.
To access the tube sheet for this work, for the upper tube sheet, the plug device is inserted through the maintenance hole provided in the end plate of the secondary side upper water chamber 8, but for the lower tube sheet, the plug device is inserted through the secondary inlet. The water chamber 8 at the lower part of the secondary side is passed through the downcomer pipe 3 connected to the nozzle 6.
Insert the plug device into the The downcomer pipe 3 is located at the center of the heat exchanger, but since it has a small diameter and a long length, it is necessary to make the equipment more compact, and the distance to the work place is longer, which reduces the overall size of the equipment. It is necessary to ensure rigidity and positioning accuracy. Furthermore, since the work space is limited, it is necessary to optimize the functions, arrangement, etc. of each part of the device.

In the present invention, the vertical drive and rotation mechanism of the device is integrated into the upper part of the downcomer pipe, and radial positioning in the water chamber is achieved by the operating head moving on an arm that opens radially like an umbrella. In the heat exchanger tube plug device designed to accomplish this, all of these operations can be performed remotely using a control device.

A heat exchanger tube plug device of the present invention is shown in FIG. The plug device includes a turning drive mechanism 14 and a vertical drive mechanism 1.
5, a clamp mechanism 16, an arm 17, an arm opening/closing mechanism 18, an operation head 19, a support cylinder 20, and a control device 21.

The turning drive mechanism and the vertical drive mechanism are shown in FIG. The vertical drive mechanism is composed of a flange 22 and a jack up device 23 of a gas pressure cylinder, and when the device is set, the verticality and vertical direction of the entire device are adjusted, and once set, it is fixed. The swing drive mechanism moves the device in the circumferential direction to approach any tube plate hole position, and the swing drive motor 25 applies rotational force to a gear 26 integrated with the support cylinder 20 to rotate the entire device. Swirl.

As shown in FIG. 6, the clamp mechanism presses three or more shoes 27 passing through the support shell 3 against the inner surface of the downcomer pipe 3 to center and steady the device.
7. Consists of wedge 29. The downcomer pipe 3 is a cylinder concentric with the tube plate, and operates a gas pressure cylinder 28 coaxially fixed to the support shell 20 to move a wedge 29 fixed to the piston shaft inside the shoe 27. By pushing in the shoe 27, the shoe 27 is pushed outward and pressed against the inner surface of the downcomer pipe 3, thereby centering and steadying the device.

As shown in FIG. 7, the arm opening/closing mechanism includes a drive motor 30, an arm 17, an arm support 31, a drive screw consisting of a male screw 32 and a female screw 33, and a female screw 3.
It is composed of a link 34 that connects the third part and the arm 17. The fulcrum of the arm and both ends of the link 34 are connected by pins. A drive motor 30 fixed to the support body 20 rotates a male screw directly connected to the motor shaft, and moves a female screw engaged with the male screw up and down. The arms connected by the links are opened and closed by moving the female threaded portion up and down. The descending pipe is very narrow, and when the plug device is suspended, the arm is closed and the opening and closing operations are performed in the lower water chamber 8. Operate the plug with the arm in a horizontal position.

The arm 17 is equipped with the equipment necessary for operating the plug, and has tooth grooves to allow movement in the radial direction, and the operating head travels on the arm by driving a gear that meshes with this arm using a motor.

One type of operation head is installed for one arm. Necessary operation heads include a tube hole detection device, a tube hole cleaning device, a plugging device, a plug inspection device, a work monitoring camera, etc., but any combination may be used depending on space or work requirements. After confirming the tube plate hole of the damaged heat transfer tube with the tube hole detection device, the device's rotation drive mechanism is activated and the tube plate hole is successively approached and worked on.

The support shell 20 is for supporting the device and ensuring rigidity, and is a hollow cylinder. A cable for supplying power to the device, a conduit for compressed gas, etc. are passed through the inside and connected to the outside.

The operation of the plug device, except for the initial setup of the device,
An external control device is installed so that everything can be controlled remotely.

This device has the advantage that positioning is easy and accurate, a series of plug operations can be performed efficiently, and work can be done in environments where access is difficult, such as under high radiation.

According to the present invention, when installing a plug on the lower tube sheet of a shell-and-tube heat exchanger, the accessibility to the tube sheet portion is improved, the positioning of the device is easy and highly accurate, and the plug It has the advantage of increased reliability, improved work efficiency, and the ability to work in environments with high radiation levels that are difficult to access due to remote control and a television monitor.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of known technology, Figure 3 is an explanatory diagram of a shell and tube heat exchanger, Figure 4 is a configuration diagram of the present invention, and Figure 5 is a turning and vertical drive mechanism of the device. FIG. 6 is an explanatory diagram of the clamp mechanism, and FIG. 7 is an explanatory diagram of the arm opening/closing mechanism. DESCRIPTION OF SYMBOLS 1...Heat exchange tube, 2...Tube plate, 3...Descent plate, 4...Primary inlet nozzle, 5...Primary outlet nozzle, 6...Secondary inlet nozzle, 7...Secondary outlet nozzle, 8...Water chamber, 9... Maintenance hole, 10...Plug device, 11...Operation rod, 12...Swivel axis, 13...Arm, 14...Swivel drive mechanism, 15...Vertical drive mechanism, 16...Clamp mechanism, 17...Arm mechanism, 18...Arm opening/closing mechanism, 19...Operation head, 20...Support cylinder, 21
...control device, 22 ... flange, 23 ... jack up device, 24 ... bearing, 25 ... swing drive motor, 26 ... gear, 27 ... shoe, 28 ... gas pressure cylinder, 29 ... wedge, 30 ... arm drive motor, 31 ... arm Support, 32...Male thread, 33
...Female thread, 34...Link.

Claims (1)

[Claims] 1. In a device for plugging tube plate holes through downcomer pipes of heat exchangers, there is a mechanism that drives the entire device in the axial and circumferential directions, a clamp mechanism that fixes the device concentrically with the downcomer pipe, and a It is characterized by consisting of an arm mechanism that opens and closes the tip of the device like an umbrella outside, a multi-operation head equipped with the necessary devices for the heat exchanger tube plug installed on the arm, and a control device that controls these. Heat exchanger tube plug device.