JPS58155317A - Water level measuring device - Google Patents

Abstract

PURPOSE:To display the amount of water in a container stably and accurately even though the conditions in the container are fluctuated to a large extent, by always supplying cooling water from the lower parts of a pressure difference pipe, which communicates the container with a reference level device, so that the temperature of the water in the differential pipes and the reference level device does not exceed a boiling point. CONSTITUTION:The reference level device 1 is communicated to the container 3 by the pressure difference pipes 2A and 2B. A differential pressure gage 4 is provided in the middle of the pressure difference pipe 2B. A cooling water supply pipe 8 is connected to the pressure difference pipe 2B on both sides of the differential pressure gage 4. A cooling water pump 9 is connected to the cooling water pipe 8. The cooling water of the specified amount described above is constantly injected to the lower end parts 1 of the pressure difference pipe 2B by the cooling water pump 9 through the cooling water supply pipe 8. Thus the temperature of the a water in the reference level device 1 and the container 3 can be maintained at the low value. Even though the pressure in the container 3 is decreased to an atmospheric pressure, possibility of boiling is completely eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water level measuring device, and more particularly to a water level measuring device suitable for measuring the amount of water held in a container of a boiler wharf in a power plant.

Figure #I1 is a schematic diagram showing an example of the configuration of a conventional water level measuring device and the degree distribution of water in a differential pressure conduit. Reference plane 1i! 1 communicates with the inside of the container 3 through two differential pressure conduits 2B, and a differential pressure needle 4 is inserted into the lower part of the differential pressure conduit 2B at Tm. The symbol "m" in the graph on the right side of the figure indicates the normal distribution of water in the differential pressure conduit 2B, and the coolant above the position indicated by the dotted line can evaporate. In addition, the dashed-dotted line shown by the code|symbol B crosses the reference surface.

In the nine prior art examples shown above, the water level in the reference surface vessel l is maintained by draining the steam from the inside of the container 3.

In this rounded differential pressure conduit 2B, subcooling is low near the base IIk surface width 1, and when there is a sudden pressure reduction in 1111I8, and there is a pressure fluctuation that drops to atmospheric pressure, the differential pressure conduit! ! Some parts of B where the water temperature is about 100C or higher are #I
However, the reference direction B may not be constant. i12
The diagram shows two people in a differential pressure conduit.

2B and reference plane 4! ! Water in 1 is boiling under reduced pressure
t-showing. When such a phenomenon occurs, the differential pressure 11t4 may not accurately indicate the amount of water held in the container 3.

Therefore, examples of countermeasures against the above-mentioned problems are shown in FIGS. 3 and 4. In the example shown in FIG. 3, the cooling pipe S is provided by making the differential pressure pipe 2B double. Cooling water W is injected into this cooling pipe s to cool the water in the differential pressure conduit 2B. This prevents the reference plane from lowering due to reduced pressure boiling of the water in the differential pressure conduit 2B. However, in such a structure, it is necessary to install a dual-purpose conduit, which is difficult to manufacture, and furthermore, it is difficult to check for leaks in the differential pressure conduit 2B, which is disadvantageous in terms of maintenance. The structure is as follows.

In the example in Figure 4, the reference rjj lost due to reduced pressure boiling
A branch pipe is provided in the differential pressure conduit 2B to supply water in the J unit from outside the system, and an injection valve 6 and a pump 7, which open when an abnormality signal 8 is received, are installed in this branch pipe to forcefully The structure is such that the cooling water is injected into the T-differential pressure conduit 2B or the reference plate 1 to recover the water in the reference plate 1. However, in such a structure, after the water in the reference surface vessel l is lost, the water level indication until it recovers is abnormal69, and it is also difficult to determine whether or not to inject water from the outside with the pump 7 and to set the injection amount. G-shuku, f!
The design of the equipment is complicated and difficult.

An object of the present invention is to provide a water level indicator that can stably and accurately indicate the amount of water held in a container even when the conditions in the container vary significantly. By constantly supplying cooling water from the lower level tS of the differential pressure conduit that runs seven times between the inside of the 11 vessel and the reference surface vessel,
The above objective is achieved by preventing the temperature of the water in the differential pressure conduit and the box Q11 from rising above one boiling point.

Hereinafter, an embodiment of the present invention will be described according to an lsS diagram, using the same reference numerals for S products as in the conventional example.

Figure 5 shows the water level needle #III of the present invention! Implementation of illumination 9
110 approximately ll configuration and 9 approximately i5! showing the temperature distribution of water in the differential pressure conduit. 1 standard WJ device 1, which is the wiring, has 2 people on the differential pressure conduit.

From 2B & ζ! It communicates with 3. Differential pressure conduit 2B
A differential pressure gauge 4 is inserted in the middle of the am.
A cooling water pump 9 is connected to this cooling water supply pipe 8. The differential pressure conduit 2B and the reference Iti device IK are constantly supplied with p cooling water by the cooling water pump 9 through the cooling water supply pipe 8.

i16 Figures (A) to (C) are the above 5! It is a figure which shows the range 8 of the cooling water injection amount of example A. (A) shows the temperature change in the reference direction with respect to the amount Q of cooling water injected from the differential pressure conduit 2B into the reference surface 1) 1 shown in Fig. 7, and (B) shows the temperature change in the reference direction with respect to the same amount of water Q. Showing the f-diameter, (C)
indicates the dynamic pressure that the differential pressure needle 4 receives with respect to the same amount of cooling water Q. Note that d in the figure indicates the existing pipe diameter, and H indicates the actual JII diameter.
The appropriate range of cooling water amount in the example is shown, and P shows the dynamic pressure that affects the instrument error. Furthermore, the amount of injected cooling water Q includes the amount of steam condensed within the reference surface vessel 1.

Range 8H of the amount of injected cooling water is the amount that maintains the water temperature at the reference surface sufficiently low (approximately 100 [1' WI) from (A), and (B) continues into the reference surface container l. In the differential pressure conduit 2B, To is small at a flow rate where the siphon effect (the effect that the differential pressure conduit 2B is blocked by cooling water due to excessive flow rate) does not occur, and furthermore (C
) is determined so that the constant error of the differential pressure gauge 4 caused by the dynamic pressure of the injected cooling water is within a sufficiently low range.

According to this embodiment, the cooling water is supplied from the lower end of the differential pressure conduit 2B to 1
By constantly injecting the amount of water into the reference plane 1 or into the container 3 by injecting the amount of water into the container 3 through the cooling water supply '#8 using the cooling water pump 9, the temperature inside the container 3 is kept low. Even if t drops to atmospheric pressure, the temperature of the water in the differential pressure conduit 2B is maintained below 100r.
There is no possibility of I# rising, and the differential pressure needle 4 has the effect of always being able to stably and accurately indicate the amount of water held in the container 3. Also, the water level gauge is rounded so that the temperature of the water in the differential pressure conduit 2B can be kept constant at all times, the density of the differential pressure needle 4 can be easily corrected, and the water level gauge is more accurate than conventional ones. There are effects that can be achieved. Furthermore, in this example, 9 tons of new cooling water pumps are installed, but if water from the make-up water system is used to supply the cooling water to the container 3, the same effect can be obtained by simply installing #8 for the cooling water supply, and the savings can be greatly reduced. There is no need to change the equipment, and it is effective not only for installation in new plants but also for back-hitting existing plants.

As described above, according to the present invention, it is possible to provide a water level needle side device that can stably and accurately indicate the amount of water held in a container even when conditions within the container vary significantly. .

[Brief explanation of drawings]

Figure s1 is an explanatory diagram showing a schematic configuration example of the conventional water level needle side device and the temperature distribution of water in the differential pressure conduit, and Figure 2 is an explanatory diagram showing the conventional water level needle side device and the temperature distribution of water in the differential pressure conduit. Show IS! Figure 3 and Figure 814 show an example of the structure of the water level needle of the 9th grade with measures taken to prevent depressurization fs#, and a fic explanatory diagram.
FIG. 5 is an explanatory diagram showing a structural example of an embodiment of the water level needle device of the present invention and the temperature distribution of water in the differential pressure conduit;
6(A) to 6(C) are diagrams for determining the amount of cooling water to be injected in this embodiment, and FIG. 7 is an enlarged schematic diagram of the base unit of this embodiment. l...Reference level device, 2A, 2B...Differential pressure conduit, 3...
・Container, 4... Differential pressure needle, 8... Cooling water supply pipe, 9.
... Cooling water pump No. 10 No. 20 No. 30 83- No. 40 No. 30

Claims (1)

[Scope of Claims] L: A reference plane device for measuring the amount of cooling water held in the container, and a differential pressure conductor communicating with this reference WJ device t-S line;
A water level measuring device comprising a differential pressure needle interposed in the middle of a differential pressure conduit, the water level needle device being characterized in that cooling water is constantly injected into the differential pressure conduit. 2. Claim #I1, characterized in that a cooling water supply pipe connected to the vicinity of the low position of the differential pressure conduit and a pump for sending cooling water to the cooling water supply pipe are installed together. Thief's water level measuring device.