JPH0346338Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention relates to the structure of a cover plate that plays an important role in preventing leakage in high-temperature and high-pressure water level gauges, particularly in multi-port water level gauges.

<Conventional technology and its problems> For high-temperature, high-pressure water level gauges, a multi-port is used that uses a round, reinforced hard glass with a diameter of about 30 mm for the glass plate due to the strength and safety of the glass used. A type water level gauge is used. On the other hand, this means that the number of locations where leakage occurs increases in proportion to the number of glass plates, and if leakage occurs at one location, the entire water level meter must be stopped. In addition, steam leakage is dangerous for operators due to the high pressure of over 100 kg/ ^cm2 , and if steam leakage occurs for a long time, the boiler will stop due to steam leakage within the periodic inspection interval. Therefore, there is a strong demand for a leak-free water level gauge. However, the working pressure of water level gauges has recently increased to 200 kg/cm ² g.
Since a boiler close to that of water is used, a highly reliable water level gauge suitable for the boiler is required. Since the number of parts that make up a water level gauge is not that large, it seems likely that the request can be met immediately, but each part must be carefully considered and how leakage prevention will be handled. There is a strong demand for extending the period until replacement, that is, the life of one port. However, when conducting these studies, there are limits to factory experiments, and it is necessary to study the results of using a practical high-pressure boiler in collaboration with the customer. Another problem is that it takes several months for the results of a single modification to be seen, requiring long-term patient observation and dedication while paying special attention to the safety of the engineers in charge. In addition, in the conventionally used multi-port water level gauges shown in Figures 7 and 8, Micafacing 1
The legs of the cover plate 4 and the protrusion of the glass plate 12, which have a great effect on cracking, deformation, and leakage, are not properly controlled. Also, if the cover plate 4 is tightened only with a conventional torque wrench, the cover plate 4 will not come apart. There is a high possibility that this will lead to cracking, deformation, and leakage of the mica facing 11. As mentioned above, setting the protrusion of the glass plate 12 from the cover plate 4 and preventing uneven tightening of the cover plate 4, that is, preventing damage to the mica facing 11, must be solved as soon as possible in order to improve the reliability of the multi-port water level gauge. This has become an extremely important issue.

Regarding the prevention of deformation of the mica facing, there is an invention disclosed in Japanese Patent Application Laid-open No. 169621/1983 filed by the applicant of the present application.

By combining the device according to the previous proposal and the means of the present invention, leakage prevention effects can be achieved even without the use of particularly skilled workers.

<Purpose of the invention> The present invention eliminates the drawbacks of the conventional technology described above, and improves the maximum working pressure of 200
The object of the present invention is to provide a high-temperature, high-pressure multi-port water level gauge suitable for a boiler with a Kg/cm ² g and evaporation rate of 1200 T/H, and particularly a cover plate tightening device used therein.

<Summary of the Means> In short, this invention consists of a transparent member consisting of a glass plate and a sealing member placed on the front and back sides of the glass plate, a water level gauge main body provided with a port for attaching the transparent member, and a transparent member. In a water level gauge equipped with a flange-shaped cover plate and cover bolts for crimping and fixing to a port part, stopper parts of the same height are provided at multiple locations on the see-through member side of the cover plate flange part, and the cover plate is fixed by the cover bolts. This water level gauge is characterized by its ability to tighten uniformly.

<Example 1> An example of this invention will be described below with reference to the drawings. The actual boiler that was installed and tested for the modification of the water level gauge parts had a maximum operating pressure of 146 kg/cm ² g and evaporation amount.
705T/H, steam temperature 339℃. The external appearance of the water level gauge used in the test is as shown in Figure 7, and the dimension between the mounting parts (distance between mounting flange centers) L is approximately
It is 530mm. The water level gauge 1 is provided with seven port portions 2 on the front and rear surfaces for attaching see-through members. A pair of see-through members 3 are attached to each of the front and rear sides of the port portion 2, which are held down by a cover plate 4 and fastened to the water level meter body by a cover vault 5. Light is supplied to each port 2 from the illustrated light source 6 through the red-green colored glass plate 7, the lens 8, and the transparent member 3. In this case, depending on whether or not water is coming to the port section 2, the red and green light rays have different refractive indexes depending on the water and steam regions, so the steam region is displayed as red and the water region is displayed as green. This shows that the water level in the drum is between the red port and the green port.

The transparent member 3 includes, in order from the steam or canned water side (in short, the main body 1a side), a vortex gasket 9, a metal gasket 10, a mica facing 11,
It consists of a glass plate 12 (a side cushion gasket 13 surrounding this glass plate), a protective mica 14, and a buffer gasket (cushion gasket) 15. The main body 1a is provided with two heat-retaining steam passages 1b to keep the temperature of the main body uniform and to prevent distortion of the seat where the micro-cutting gasket that protects the glass plate comes into contact. This idea successively improves the defective parts of each component that makes up the high-temperature, high-pressure multi-port water level gauge.
When solving the problem, this was done regarding the tightening device for gaskets, which has a particularly important function in terms of leakage.

FIG. 9 is an enlarged partial cross-sectional view of section A in FIG. 8. Each gasket including the vortex 9 is located between the port seat 1c of the main body and the cover plate 4, and plays an important role in maintaining airtightness of steam of 146 kg/cm ² g and temperature of 339°C. That is, each gasket including the vortex gasket 9 maintains airtightness between the port seat 1c and the cover plate 4. Moreover, the temperature of the water level gauge main body changes depending on the steam temperature when starting the boiler and during pressure raising/lowering work such as stopping the boiler, and accordingly, the cover vault 5 for tightening the cover plate 4 and other related parts change depending on the respective temperatures. It expands and contracts, and as a result, the dimension f between the port seat 1c and the metal gasket 10 changes slightly. Also, during operation, the glass plate 12 receives forces of 146 kg/cm ² g and 1505 kg/cm ² g through the mica facing 11, and the vortex gasket 9 is responding and following suit. That is, the metal gasket and mica facing must be in contact with each other with elasticity at their contact surfaces while receiving a force of 1505 kg/cm ² g. The vortex gasket has an annular coil retaining ring 9a, as shown in cross section in FIG. ) is a thin steel plate with a dogleg cross section wrapped with asbestos 9c in the shape of a sandwich, and the thickness (corresponding to the f dimension) is usually 5.3 mm. Conventionally, such gaskets were tightened using a torque wrench, but due to the influence of rust, etc., the distance g between the cover plate 4 and the port seat 1c was not necessarily constant, and the distance g between the squares of each port 2.0～
It was tightened to a varying value of around 3.6mm.
Therefore, cracks and peeling 11a of the mica occur as shown in the damage diagram of the mica facing 11 in FIG. 11, and this causes many chances of damage to the mica facing 11 and the metal gasket 10. Also, if you carefully observe the damaged mica facing, it will crack at the contact surface with the glass corner.
1b occurs, and as a result of actual machine experiments, there are cases where the protrusion of the cover plate 4 and glass plate 12 is larger than 0.45 mm before tightening, and after tightening.
Mica facing 11 for items larger than 0.2mm
This causes many chances of damage to the metal gasket 10. This invention is intended to improve these drawbacks, and its structure is shown in FIGS. 1 to 3. In this invention, stoppers 16a having a length of about 3.0 mm are provided at the four corners of the cover plate to define the tightening limit. The stoppers at the four corners come into contact with the water level gauge body evenly, eliminating uneven tightening of gaskets and making it possible to extend the replacement interval for each part without damaging the mica facing. In addition, gauges 16b and 16c are provided on the upper end side of the uppermost cover plate to form a stepped half-moon recess to measure the protrusion of the glass plate, which plays an important role in preventing damage to the mica facing. When the cover plate, buffer gasket 15, protect mica 14, and glass plate 12 are assembled and the lower end surfaces of the cover plates are connected, the gap shown in Fig. 4 is measured with a gap gauge, and the glass plate is assembled. This is to determine whether or not it is appropriate. (0.45mm before tightening, 0.20mm after tightening) This greatly increases the effect of preventing damage to mica facing. Also, there is no need to prepare gauges each time at the site.

<Example 2> Figures 5 and 6 show the cover plate 4 and port seat 1a.
The idea behind the idea of quantifying the distance between is the same, but the structure is different. In this embodiment, a spacer plate 17 of about 3.0 mm is inserted in place of the square stopper 16a of the cover plate.

<Effects of the idea> By implementing this idea, results over a one-year period show that the interval between replacing gaskets due to steam leakage can be extended by approximately 60%, and maintenance work that was previously performed by unskilled personnel has been achieved. This has the effect of completely eliminating the leakage that often occurs during re-operation, resulting in a reliable product, and it has various effects such as making it possible to easily modify existing equipment.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a cover plate showing an embodiment of the present invention, Fig. 2 is a Z-Z view of Fig. 1, and Fig. 3 is a WW view of Fig. 2, showing a glass protrusion gauge. FIG. 4 is a front view of a gauge cover plate showing how it is used, with a half-moon stepped recess formed on the upper end surface of the cover plate to serve as a gauge, and FIG. 5 is a drawing of the spacer plate of the second embodiment. Fig. 6 is a Y-Y view of Fig. 5, Fig. 7 is an external view of the multi-port water level gauge, Fig. 8 is an explanatory diagram showing the see-through member exploded, and Fig. 9 is a view of part A of Fig. 8. Enlarged partial sectional view,
FIG. 10 is a plan view showing damage to the metal gasket, and FIG. 11 is a plan view showing damage to the mica facing. 1...Water level gauge body, 16...Cover plate,
16a...stopper, 17...spacer plate.

Claims (1)

[Scope of utility model registration request] A transparent member consisting of a glass plate and a sealing member placed on the front and back sides of the glass plate, a water level gauge body having a port for attaching the transparent member, and a flange-shaped flange for crimping and fixing the transparent member to the port. A water level gauge provided with a cover plate and cover bolts, characterized in that stopper portions of the same height are provided at multiple locations on the see-through member side of the cover plate flange portion to enable uniform tightening of the cover plate with the cover bolts. water level gauge.