JP2003028588A - Plate heat exchanger and its maintenance method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate heat-exchanger and its maintenance method, in which covering for receiving radioactive fluid in a maintenance time is eliminated, and a heat-transfer plate can be washed in the as-is state of the heat exchanger without disassembling the plate. SOLUTION: In the plate heat-exchanger, upper and lower guide-bars 4, 5 respectively are placed in a fixed frame 1. A floating frame 6 is placed between a guide-bar support 7 and the fixed frame 1. Heat exchangers 8 are placed between the floating frame 6 and the fixed frame 1. A receiving pan 16 for the heat exchanger is placed below the heat exchanger 8. The pan 16 receives the radioactive fluid dropping in the maintenance work of the heat exchanger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate heat exchanger for handling a radioactive fluid in a nuclear power plant or the like and a maintenance method therefor.

[0002]

2. Description of the Related Art A plate heat exchanger is used as a part of a heat exchanger that handles a radioactive fluid such as a nuclear power plant. An example of this plate heat exchanger is shown in FIGS.
Will be described.

FIG. 7 shows a side view of the plate heat exchanger. In FIG. 7, reference numeral 1 is a fixed frame, and the fixed frame 1 is erected on a floor surface 3 of a foundation 2. The fixed frame 1 has two upper and lower upper guide bars 4 along the horizontal direction.
And the lower guide bar 5 is attached.

The upper guide bar 4 and the lower guide bar 5 are provided with a floating frame 6 which moves laterally, and the ends of the upper guide bar 4 and the lower guide bar 5 are attached to a guide bar support 7. The lower ends of the floating frame 6 and the guide bar support 7 are erected on the floor surface 3 of the foundation 2.

The heat exchanger 8 is provided between the fixed frame 1 and the floating frame 6 and between the upper guide bar 4 and the lower guide bar 5.
As shown in FIG. 8, the heat exchanger 8 has a wave-shaped heat transfer plate 9
Is composed of several tens to several hundreds, which are tightened by tightening bolts 10 and are united so that they can be disassembled freely. The heat transfer plate 9 is provided with a primary-side flow path hole 12 and a secondary-side flow path hole 13 by partitioning a gasket 11, and the secondary-side flow path hole 13 is provided with a ring-shaped gasket 11.

[0006] The primary side fluid and the secondary side fluid alternately flow between a plurality of heat transfer plates 9, 9 in which the primary side fluid and the secondary side fluid are superposed by the flow passages defined by the gasket 11, and heat exchange is performed via the heat transfer plate 9. Done. In FIG. 7, reference numeral 14 is a primary side fluid inflow pipe, and 15 is a primary side fluid outflow pipe.

On the other hand, in order to clean the heat exchanger 8, especially the heat transfer plate 9 and replace the gasket 11, it is necessary to perform regular maintenance. When performing the maintenance work, the tightening bolt 10 is removed and the floating frame is moved. 6 is moved to the guide bar support 7 side along the upper and lower guide bars 4 and 5 to widen the gap between the heat transfer plates 9 and, if necessary, removed from the upper and lower guide bars 4 and 5 to clean the heat transfer plate 9 and Replace gasket 11.

[0008]

When performing maintenance work on the plate heat exchanger, the heat exchange body 8 and the heat transfer plate 9 are removed. At this time, the radioactive fluid accumulated in the heat exchange body 8 is removed from the floor. Drip to surface 3. Therefore, it is necessary to cover and cure the floor surface 3 with, for example, a poly sheet so that those radioactive fluids do not scatter, and when cleaning the heat transfer plate 9, the radioactive fluid that adheres scatters, so that heat exchange is performed. There is a problem that the body 8 must be moved to a washable place.

The present invention has been made to solve the above-mentioned problems, and it is not necessary to perform treatment such as curing to receive the radioactive fluid that drip during maintenance work.
Without disassembling the heat exchanger, the heat transfer plates can be washed while the heat transfer plates are bound together, and further, the radioactive fluid can be minimized from leaking to the outside. A plate-type heat exchanger and a maintenance method thereof are provided.

[0010]

The invention according to claim 1 is
A fixed frame that is erected on the foundation, upper and lower guide bars attached in two steps in the horizontal direction of this fixed frame, and the end portions of the upper guide bar and the lower guide bar are fixed to stand on the foundation. A guide bar support to be installed, a floating frame interposed between the guide bar support and the fixed frame and erected movably upright on the foundation, and a plurality of sheets provided between the floating frame and the fixed frame. It is characterized by comprising a heat exchange body in which heat transfer plates are assembled and bound so as to be disassembled freely, and a heat exchange body tray provided below the heat exchange body.

According to the present invention, when the radioactive fluid accumulated in the heat exchange body drops during maintenance of the heat exchanger, it can be collected by the heat exchanger tray, so that it is necessary to cure it with a poly sheet such as a polyethylene sheet. It is also possible to prevent contamination of the surroundings.

According to a second aspect of the present invention, there is provided a fixed frame which is erected on a foundation, an upper guide bar and a lower guide bar which are vertically attached to the fixed frame, and the upper guide bar and the lower guide bar. Between the guide bar support fixed at the end and standing on the foundation, a floating frame interposed between the guide bar support and the fixed frame and movably standing on the foundation, and between the floating frame and the fixed frame. On the foundation so as to surround the heat exchange body, which is provided in a plurality of heat transfer plates and is bundled so as to be disassembled freely, the fixed frame, the guide bar support, and a maintenance area laid around them. And a maintenance area saucer installed in.

According to the present invention, even if the radioactive fluid accumulated in the heat exchanger is dropped on the plate type heat exchanger and the maintenance area, it can be collected by the tray for the maintenance area, and the internal fluid can be collected even during the maintenance work. Diffusion of radioactive fluid can be prevented.

The invention according to claim 3 is characterized in that a drain pipe is attached to the heat exchange element tray or the maintenance area tray. According to the present invention, by attaching the drainage pipe to the tray, the radioactive fluid drainage pipe generated during the maintenance work can be discharged through the drainage pipe, so that the radioactive fluid need not be treated and the maintenance work can be facilitated.

The invention according to claim 4 is characterized in that an isolation wall extending upward from an inner peripheral edge of the maintenance area tray is provided. According to the present invention, a clean room is constituted by the saucer, the isolation wall, and the ceiling, and when cleaning is performed in the state of the heat exchange body in which a plurality of heat transfer plates are bound during maintenance work, the radioactive fluid is prevented from scattering to the outside. It can be prevented.

The invention according to claim 5 is characterized in that the heat exchange element is integrally removed from the upper guide bar, and a removal guide bar having a suspending portion is provided. According to the present invention, by making a part of the guide bar detachable, the heat exchange element can be integrally suspended in the guide bar and can be removed and transported to the decontamination area.

According to a sixth aspect of the present invention, a heat exchange element is provided between the fixed frame and the floating frame, and a plurality of heat transfer plates are assembled and united so that they can be disassembled. The guide bar is provided on the other side of the floating frame. In a maintenance method for a plate heat exchanger having a support, a saucer is provided below a maintenance area including the area where the heat exchanger is installed and maintenance work is performed, or below the heat exchanger, and an inner peripheral portion of the saucer is moved upward. An isolation wall or a flexible poly sheet is provided toward the plate, and the plate heat exchanger or the heat transfer plate is cleaned in the isolation wall or the flexible poly sheet. According to the present invention, the heat transfer plate of the heat exchanger can be washed by setting a clean area in which the entire heat exchanger is cured with a poly sheet or the like using the saucer.

According to a seventh aspect of the present invention, after cleaning the partition wall or the upper end opening of the flexible poly sheet to form a clean room, the plate heat exchanger or the heat transfer plate is washed. Is characterized by.

According to the present invention, in the state of the heat exchange body in which a plurality of heat transfer plates are bound in the clean room formed by the isolation wall and the ceiling, the tightening bolts are loosened and the gap is expanded to clean and clean the gasket. Exchanges can be made.

In the invention according to claim 8, a detachable guide bar is provided on the upper guide bar provided between the fixed frame and the guide bar support, and the heat guide is provided at the position of the detachable guide bar. The heat exchanger may be moved to the maintenance area after the heat exchanger is moved and attached to the removal guide bar integrally. According to the present invention, by partially removing the guide bar, it is possible to remove the heat exchanger as a unit in a suspended state and transport it to the decontamination area.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIG. FIG. 1 is a side view showing a part of a plate heat exchanger according to the present embodiment in a vertical cross section. In FIG. 1, the same parts as those in FIG. .

The present embodiment differs from the conventional example shown in FIG. 7 in that a heat exchanger tray 16 is provided directly below the heat exchanger 8 and below the fixed frame 1 and the floating frame 6. The other parts are the same as those in FIG.

According to the present embodiment, when the radioactive fluid accumulated in the heat exchanger 8 drops during maintenance of the heat exchanger, it can be received and collected by the heat exchanger tray 8. There is no need to cure with policy etc.,
It is possible to prevent contamination of the surroundings.

Next, a second embodiment according to the present invention will be described with reference to FIGS. 2 (a) and 2 (b). FIG. 2A is a side view showing a part of the present embodiment in a vertical cross section, and FIG.
It is a top view of (a), and in FIG. 2, the same parts as those in FIG. 7 are designated by the same reference numerals, and the description of the overlapping parts will be omitted.

The present embodiment is different from the first embodiment in that a maintenance area tray 17 is provided instead of the heat exchanger tray 16. Maintenance area saucer 17
2 includes a plate heat exchanger including the fixed frame 1 to the guide bar 7 as shown in FIG. 2B, and the heat exchanger is removed, dismantled, washed, and a gasket is also included.
It is laid on the floor surface 3 of the foundation 2 within a range that covers and covers the entire maintenance area 18 including a work place where the replacement of 11 and the binding and assembly of the heat transfer plate 9 are performed.

According to this embodiment, since the radioactive fluid dripping during the maintenance work of the heat exchanger can be received by the maintenance area tray 17, it is not necessary to cure it with a poly sheet or the like, and the surrounding environment is not polluted. It can be prevented.

A third embodiment according to the present invention will be described with reference to FIG. FIG. 3 is a side view showing a part of the present embodiment in a longitudinal sectional view, and the present embodiment is the same as the second embodiment.
As shown in FIG. 3, the drainage pipe 19 is attached to the tray 17 for the maintenance area. The downstream side of the drainage pipe 19 passes through the inside of the foundation 2 and is connected to an outside, for example, a radioactive waste liquid treatment tank (not shown).

According to the present embodiment, the radioactive fluid generated at the time of maintenance can directly flow out through the drain pipe 19, so that it is not necessary to treat the radioactive fluid in the maintenance area 18. The drain pipe 19 may be provided in the heat exchange element tray 16 in the first embodiment.

Next, a fourth embodiment according to the present invention will be described with reference to FIGS. 4 (a) and 4 (b). This embodiment is the second
In the embodiment of the present invention, as shown in FIG. 4A, a partition wall 20 is provided upright from a peripheral portion in the maintenance area tray 17 and a ceiling plate that closes an upper end opening of the partition wall 20. There is 21. Note that FIG.
It is a top view of (a), The isolation wall 20 isolates the maintenance area 18 required for maintenance work.

The maintenance area 18 is shown in FIG. 4 (b).
As is clear from the above, it is a range including the area necessary for performing the work of the entire plate heat exchanger and the maintenance area.

According to the present embodiment, the maintenance area 18 is surrounded by an isolation wall surrounding the maintenance area 18.
By arranging 20 in a standing manner, it is possible to prevent the radioactive fluid from scattering outside when the cleaning work is performed in a state where the plurality of heat transfer plates 9 are bound together. In addition to regular cleaning,
You can also do jet cleaning work. The ceiling plate 21 can be removed for maintenance work.

Next, a fifth embodiment according to the present invention will be described with reference to FIGS. 5 (a) and 5 (b). This embodiment is the third
In the embodiment, the simple type flexible isolation wall 22 is provided by using a poly sheet or the like instead of the isolation wall 20. That is, the maintenance method of the plate heat exchanger in which the entire heat exchanger using the maintenance area tray 17 and the maintenance area 18 are configured in a clean room cured with a flexible sheet such as a poly sheet to wash the heat transfer plate 9 Is.

According to the present embodiment, even if the cleaning work is performed with the heat transfer plate 9 attached to the heat exchanger body 8, the entire surface is covered with the isolation wall 22.
It is possible to prevent the radioactive fluid from scattering to the outside.

Next, a sixth embodiment according to the present invention will be described with reference to FIGS. FIG. 6 (a) shows the operation of the plate heat exchanger, FIG. 6 (b) shows the same maintenance work, and FIG. 6 (c) shows the suspension of the heat exchange element 8 in FIG. 6 (b). 6 (d) shows a side view of FIG.

In this embodiment, a detachable guide bar 4a is provided on a part of the upper guide bar 4 so that it can be pulled upward, and a ring-shaped protrusion 23 is provided on the upper surface of the detachable guide bar 4a. The suspension wire 24 for suspending the protrusion 23 is configured to be attached to the protrusion 23.

The removal guide bar 4a is formed at both ends thereof with downwardly-inclined inverted C-shaped taper portions 4b so as to be detachable. In addition, the transmission plate 9 is shown in FIG.
As shown in (d), dovetail-shaped notch grooves 25 are formed at both upper and lower ends, and the lower end portions of the ring-shaped projections 23 are engaged with the notch grooves 25 so as to be detachably attached.

According to the present embodiment, the upper guide bar 4
The heat exchanger 8 can be removed by removing a part of
By being configured to be lifted as shown in (d), the heat exchanging body 8 is suspended from the removing guide bar 4a and removed as a unit, and the maintenance area 18
And, although not shown, it is possible to move to another decontamination area. As a result, the heat exchange element 8 can be handled in an integrated state, so that it is possible to minimize the leakage of the radioactive fluid to the outside.

[0038]

According to the present invention, since the radioactive fluid accumulated in the heat exchanger during the maintenance work can be received by the tray, the floor surface curing treatment with a poly sheet or the like becomes unnecessary.

According to the maintenance method of the present invention, the plate heat exchanger can be isolated from the outside.
Cleaning work can be performed with the heat transfer plate attached to the heat exchanger. Further, since the heat exchange element can be easily moved in an integrated state, leakage of the radioactive fluid from the maintenance area to the outside can be minimized.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment according to the present invention.

FIG. 2A is a side view showing a second embodiment according to the present invention, and FIG. 2B is a plan view of FIG.

FIG. 3 is a side view showing a third embodiment according to the present invention.

4A is a side view showing a fourth embodiment according to the present invention, and FIG. 4B is a plan view of FIG.

5A is a side view showing a fifth embodiment according to the present invention, and FIG. 5B is a plan view of FIG.

FIG. 6A is a side view showing a state during operation according to a sixth embodiment of the present invention, FIG. 6B is a side view showing a state during maintenance, and FIG. The side view at the time of suspension, (d) is a front view of (c).

FIG. 7 is a side view showing a conventional plate heat exchanger.

8 is a development view of the heat transfer plate group in FIG.

[Explanation of symbols]

1 ... Fixed frame, 2 ... Foundation, 3 ... Floor surface, 4 ... Upper guide bar, 4a ... Removal guide bar, 4b ... Tapered portion,
5 ... Lower guide bar, 6 ... Floating frame, 7 ... Guide bar support, 8 ... Heat exchanger, 9 ... Heat transfer plate, 10 ... Tightening bolt, 11 ... Gasket, 12 ... Primary side flow passage hole, 13 ...
Secondary side flow path hole, 14 ... Primary side fluid inflow pipe, 15 ... Primary side fluid outflow pipe, 16 ... Heat exchanger pan, 17 ... Maintenance area pan, 18 ... Maintenance area, 19 ... Drain pipe, 20 ... Isolation wall, 21 ... Ceiling board, 22 ... Simple flexible isolation wall, 23
… Ring-shaped projections, 24… Suspended wires, 25… Notched grooves.

Claims (8)

[Claims] 1. A fixed frame that is erected on a foundation, an upper guide bar and a lower guide bar that are attached in two steps in the horizontal direction of the fixed frame, and fixed ends of the upper guide bar and the lower guide bar. A guide bar support standing upright on the foundation, a floating frame interposed between the guide bar support and the fixed frame and movably standing upright on the foundation, and between the floating frame and the fixed frame. A plate-type heat exchange characterized by comprising a heat exchange body provided with a plurality of heat transfer plates assembled and united so as to be disassembled, and a heat exchange body tray provided below the heat exchange body. vessel. 2. A fixed frame which is erected on a foundation, an upper guide bar and a lower guide bar which are vertically attached to the fixed frame, and end portions of the upper guide bar and the lower guide bar which are fixed to each other. A guide bar support erected on the foundation, a floating frame interposed between the guide bar support and the fixed frame and movably erected on the foundation, and a plurality of sheets provided between the floating frame and the fixed frame. A heat exchanging body in which heat transfer plates are assembled and bundled so as to be dismantled, and a maintenance area installed on the foundation so as to surround the fixed frame, the guide bar support and a maintenance area laid around them. A plate-type heat exchanger, comprising: a saucer. 3. The plate heat exchanger according to claim 1, wherein a drain pipe is attached to the tray for the heat exchanger or the tray for the maintenance area. 4. The plate heat exchanger according to claim 2, further comprising an isolation wall extending upward from an inner peripheral edge of the maintenance area tray. 5. The plate heat exchanger according to claim 1, wherein the upper guide bar is provided with a detaching guide bar for detaching the heat exchange body as a unit and having a suspending portion. 6. A plate type heat exchanger having a heat exchange body, in which a plurality of heat transfer plates are assembled and united so as to be disassembled, between a fixed frame and a floating frame, and a guide bar support is provided on the other side of the floating frame. In a maintenance method for an exchanger, a pan is provided below a maintenance area including the area where the heat exchanger is installed and maintenance work is performed or below the heat exchanger, and an isolation wall or a flexible wall is provided upward from an inner peripheral edge of the pan. A maintenance method for a plate heat exchanger, wherein a policy is provided, and the plate heat exchanger or the heat transfer plate is washed in the isolation wall or the flexible polysheet. 7. The cleaning operation of the plate heat exchanger or the heat transfer plate is performed after closing the upper end opening of the isolation wall or the flexible poly sheet to form a clean room. 6. The maintenance method of the plate heat exchanger according to 6. 8. A removable guide bar is provided on an upper guide bar provided between the fixed frame and the guide bar support, and the heat exchanger is moved to the position of the removable guide bar. 7. The plate-type heat exchanger maintenance method according to claim 6, wherein the heat exchanger is lifted and integrally attached to the removal guide bar, and the heat exchanger is moved to the maintenance area.