JPH0240402A - Disassembly of inner lid of manhole of feed water heater - Google Patents

Abstract

PURPOSE:To make it possible to remove easily the inner lid from an elliptical opening by installing an arm in the circumference of a manhole and providing the arm with a shaft which are movable up and down and slidable by the operation of a handle. CONSTITUTION:To the manhole 6 of the water chamber of a heater 1 an arm 5 is fixed by a handle 4. The arm 5 is provided with a shaft 11 which is lifted up and down by the rotational operation of a handle 10. To the shaft 11 a shaft 7 is connected which is slid right and left by the operation of a handle 13. And, the shaft 7 can be rotated by 90 deg. by a handle 12. When the inner lid 2 of the manhole 6 is removed, at first the shaft 7 is adjusted to the height of the center of the manhole 6 by the handle 10, and the shaft 7 is inserted by the handle 13 to connect the inner lid 2 by pin. Next, a york 3 and bolt 8 are removed and the shaft 7 is further pushed in to bring the inner lid 2 to the free state. The lid 2 is then rotated by 90 deg. by the handle 12 and after the longitudinal direction of the inner lid 2 is positioned in the up-and-down direction, it is positioned horizontally to be pulled out easily from the opening.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for disassembling the inner cover of a manhole for maintenance of a feedwater heater supplied to a power plant, and is particularly applicable to high-bore feedwater heating where the inner cover is heavy. Concerning how to open and close the manhole of the vessel.

[Conventional technology]

Conventionally, when disassembling a water heater manhole, the shaft with a handle that connects to the inner cover is suspended from a chain block, and disassembly and restoration are carried out manually.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the inner lid is lifted and moved manually in an unstable state. Therefore, there is a high potential for injury such as getting caught during work as there is no consideration given to accident prevention and quality control.
Because the inner cover is unstable, there are problems such as the risk of damaging the manhole seal. Figure 1 shows the conventional decomposition method. The inner cover 2, which weighs approximately 100 kg, is connected to the shaft 4 suspended from a hook on the ceiling by turning a chain block, and disassembled using the handle 5. To remove the inner cover 2 from the oval opening, follow the steps below. It is necessary to perform the following operations.

(1) Connect the inner cover 2 and shaft 4 by turning the pin and connect the inner cover 2
Remove the yoke 3 and bolts and nuts 8 that are fixing the.

(2) Push the inner lid 2 inside by operating the handle 5.

At this time, since the weight of the inner lid acts, balance is maintained using the handle 5.

(3) Rotate the handle 5 by 90'' to align the longitudinal direction of the inner lid 2 with the vertical direction.

(4) Turn the vertically oriented inner lid 90 degrees around the shaft pin to make it horizontal.

(5) The inner cover 2 in the horizontal direction is lowered from the center of the manhole opening in the circle, so the chain block 6
Raise your level.

(6) Pull the handle 5 outward and pull it out of the water heater 1.

In this way, a heavy object of over 100 kg is lifted at the - point,
It is unavoidable to turn the sleeve and work in an unstable state, making it difficult to move smoothly, and unavoidable risks such as getting caught due to unexpected center of gravity shifts due to unbalance. .

An object of the present invention is to provide a method for reliably and safely removing and attaching a heavy inner lid.

[Means for solving the problem] The above purpose is achieved by attaching an arm supporting the inner cover to the water heater manhole or its surroundings, and attaching a shaft that can be slid by rotating the arm and operating the handle. This is achieved by supporting and moving the inner lid in a stable state.

In addition, in plants that are already in operation, it is impossible to fix the arm to the water heater ice chamber and manhole using welding or bolts, so it can be fixed using a handle installed near the manhole. do.

[Effect]

Using the handle of the water heater manhole, secure the arm with a bolt. The shaft installed vertically from the arm adjusts the height of the inner lid to the center of the opening part by operating the handle when pulling it out from the installed state. Further, the horizontally attached shaft operates to push the inner cover inside, rotate it 90', make it horizontal, and then pull it out to the outside.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

Attach the handle 5 to the ice chamber manhole 6 of the water heater 1.
Fix it using. Connected to the arm 5 is a shirt 1-11 which can be moved up and down by rotating a handle 1o, and a shaft 7 which can similarly be slid left and right by operating a handle 9 to the shaft 11. The shaft 7 has a structure that can be rotated by 90' with the handle 12. To remove the manhole inner cover 2 of the feed water heater 1, operate the handle 1o and move the shaft 7 to the height of the center of the manhole 6, that is, Adjust to the center height of the inner lid 2. next,
Operate the handle 9 to connect the inner cover 2 with the pin 13, and remove the yoke 3 and bolt 8. Next, handle 9
Operate to push the inner M2 inward to make it free. Next, operate the handle 12 to rotate it 906 times,
Adjust so that the longitudinal direction of the inner lid 2 is in the vertical direction. After reaching this state, the inner lid 2 is tilted downward around the pin 13 to bring it into a horizontal state. The center of the horizontal inner lid 2 is
Since it is below the center of the opening of the manhole 6 and the opening is oval, there will be interference, so operate the handle °10 and raise it until the center of the inner cover 2 matches the center of the opening of the manhole 6. .

Next, the inner cover 2 is moved to the outside of the water chamber 1 by operating the handle 9 and removed. As described above, the support height adjustment and horizontal movement of the inner lid 2 can be performed in a stable state and can be performed reliably, so there is no danger of accidents such as getting caught, and work safety is increased. Further, it is possible to protect the inner cover 2 and the seal portion inside the manhole 6, which are important for preventing leaks during operation, from bruises caused by contact during operation. In addition, since contact with parts that remain unchanged during disassembly can be prevented, quality can be maintained by preventing damage to the sealing part. In addition, there is no need for work such as welding or screw processing on the ice chamber of the feed water heater or manhole, and it can be used in all operating plants.

〔Effect of the invention〕

According to the present invention, the inner cover of the feed water heater can be supported and moved by operating the handle, and the disassembly and installation work of the inner cover can proceed in a stable state, thereby increasing the safety of the work.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, and FIG. 2 is an explanatory diagram of the prior art. 1. Water heater, 2. Inner lid, 3. Yoke, 4.
・Handle, 5... Arm, 6... Manhole, 7, 11
... Shaft, 8... Bolt, 9... Missing number, 10.
12゜13...handle, 14...pin.

Claims (1)

[Claims] 1. A method for disassembling the manhole inner cover of a feedwater heater for thermal or nuclear power plants using a device consisting of an arm attached to the manhole or its surroundings and a slidable shaft.