JPS5840126B2 - Moisture separator level switch test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drain water level detection level switch (hereinafter referred to as
(abbreviated simply as level switch).

In turbine plants, moisture separators are installed to remove moisture contained in steam flowing into the turbine, and this level switch detects the water level of condensate accumulated in the moisture separator. , the turbine operation is stopped when the water level reaches a level that interferes with turbine operation.

In recent plants, this level switch is multiplexed (for example, 2-out-of-3 system) to improve the reliability of drain detection and to improve the reliability and safety of the entire plant.

However, in order to improve reliability even in the case of multiplexing, it is necessary to improve the reliability of the level switch itself.

To do this, check the operation of the level switch regularly,
Efforts must be made to prevent malfunctions and malfunctions.

Conventionally, the operation of the plant had to be stopped to perform this operation check, which caused a decrease in the plant's operating rate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a moisture separator level switch test device that eliminates the above-mentioned drawbacks and allows periodic operation checks of the level switch without interfering with plant operation. .

In order to achieve this object, the present invention provides a moving means for moving a float up and down without depending on the level of moisture stored in a moisture separator, and an upper and lower limit of the float that is moved up and down by this moving means. and an electric signal generating means for excluding an electric signal specifying stopping and canceling the flow of the medium passing through the moisture separator.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of the present invention, in which a moisture separator 1
2. A steam port 16, a steam outlet 17, and a drain pipe 14 are provided, and steam 18 flows in from the steam inlet 16, separates the drain 13 into the moisture separator 12, and discharges from the steam outlet 1T to the turbine. Inflow.

The level switch 20 is installed in parallel with the moisture separator 12, and has a level switch body 8 which houses a float 9 and has a rod 7 whose lower end is connected to the float 9 so as to be movable up and down.
, a limit switch 5 for detecting the upper limit position of the water level, and a limit switch 6 for detecting the lower limit position of the water level, which are operated by the rod T, and the level switch main body 8 has one end connected to the upper and lower parts thereof, and the other end connected to the moisture separator. The moisture separator 12 is connected to the moisture separator 12 through a drain detection pipe 11 connected to the container 12 .

A link mechanism 10 is engaged with the end of the rod 7 opposite to the float 9.

This link mechanism 10 is connected to a piston 15 that slidably slides within an air cylinder 4 mounted on the level switch body 8.

The air inlet 4a of the air cylinder 4 is connected to the air outlet 21a of the solenoid valve 2 via the air pipe 3, and the compressed air 1 is guided to the upper part of the piston 15 in the figure.

The piston 15 is pushed down against the restoring spring 19 by the compressed air introduced from the air intake port 4a, and the rod 7 is moved upward via the link mechanism 10.

The solenoid valve 2 has an air intake port 21b that communicates with a compressed air source (not shown), an air discharge port 21c that discharges intake compressed air, an air discharge port 21a that connects to the air intake port 4a of the air cylinder 4, and the solenoid valve 2. slides freely inside the
It includes a spool 22, one end of which is coupled to the electromagnetic part 2a.

When the electromagnetic valve 2 is energized, the spool 22 moves in the direction of the electromagnetic part 2a against the restoring spring 23, closes the air outlet 21c, and establishes electrical continuity between the air intake port 21b and the air outlet 21a.

When the solenoid valve 2 is demagnetized, the spool 22 is
returns to its original position, the compressed air intake port 21b closes,
The air outlets 21b and 21c are electrically connected, and the restoring spring 19 of the air cylinder 4 causes air to be discharged from the air outlet 21c toward the vent of the solenoid valve 2.

Along with this operation, the piston 15 and the link mechanism 10
The rod 7 moves downward through the.

With the above configuration, the float 9 moves up and down together with the rod 7,
The up and down movement can be confirmed by the operation signals of the water level upper and lower limit position limit switches 5 and 6.

Since the electric circuit of the turbine plant is configured so that the turbine stops when the water level upper limit position limit switch 5 is activated, the signal that excites the solenoid valve 2 excludes the signal that stops the turbine at the water level upper limit position. Electric signal generating means (not shown) is attached to the electric circuit.

This exclusion is canceled by an electric signal from the water level lower limit position limit switch 6.

The test procedure of this level switch test device will be explained.

(1) Energize the solenoid valve 2, attract the spool 22 and introduce the compressed air 1, and the piston 15 of the air cylinder 4
is pushed down and the float 9 is pushed up via the link mechanism 10.

(2) The rod 7 integrated with the float 9 operates the water level upper limit switch 5. Continue excitation of the solenoid valve 2 at step 1, and test the operation of the limit switch 5.

(3) Even if the limit switch 5 operates, the circuit for stopping the turbine is excluded, so the turbine plant continues normal operation regardless of the operation of this level switch test device.

(4) When the water level upper limit switch 5 operates, the solenoid valve 2 is demagnetized, the air in the air cylinder 4 passes through the air outlet 21c of the solenoid valve 2, is discharged from the vent, and the float 9
Return to the original position and operate the water level lower limit position limit switch 6 to test the operation of this limit switch 6.

Here, the turbine stop signal cancels the exclusion, so the water level upper limit position limit switch 5 returns to the normal state of stopping the turbine when the level of the drain 13 in the moisture separator 12 occurs.

Next, an example of a circuit that automatically performs the above-mentioned test will be explained with reference to FIG.

In Figure 2, the same symbols as in Figure 1 indicate the same things,
25 is an OR circuit, 26 is an AND circuit, and 2T is a signal holding circuit.

When the push button 28 is pressed, an output is turned on to the OR circuit 25 and the solenoid valve 2 is energized.

The above output is held by the signal holding circuit 27, and the solenoid valve 2 continues to be energized until the water level upper limit position signal 29 is generated.

The generation of the water level upper limit position signal 29 is confirmed by lighting the upper limit indicator lamp 30.

On condition that the push button 28 is released and the water level upper limit position signal is generated, the AND circuit 26 operates and a turbine stop signal is generated.

Therefore, the turbine does not stop while the push button 28 is in operation.

The solenoid valve 2 is demagnetized by the generation of the water level upper limit position signal 29.
The water level lower limit position signal 31 is generated, the lower limit indicator lamp 32 lights up, the push button 28 is turned off, and the test ends.

If the level switch 20 is malfunctioning, the upper and lower limit indicator lamps 30 and 32 will not light up, so the malfunction can be known from this.

Next, another embodiment of the present invention will be explained with reference to FIG.

In FIG. 3, the same reference numerals as in FIG. 1 indicate the same components.

The rod 34 is the water level upper and lower limit position limit switch 5
and 6, whose end opposite to the float 9 is connected to an electromagnetic solenoid 35.

Therefore, by energizing the electromagnetic solenoid 35, the float 9 of the level switch 20 can be lifted.
The level switch 20 can be tested using the same explanation as the embodiment described in FIG.

An example of a circuit that automatically performs the test shown in Figure 3 is shown in Figure 4.
As shown in the figure.

In FIG. 4, the same reference numerals as in FIG. 2 indicate the same components.

When the push button 28 is pressed, the output is turned on to the OR circuit 25 and the electromagnetic solenoid 35 is excited.

The following operations are the same as those explained in FIG.

As mentioned above, there is a moving means that moves the flow up and down regardless of the water level of the drain in the moisture separator, and a medium that passes through the moisture separator at the upper and lower limits of the float that moves up and down by this moving means. Since we have installed an electric signal generation means that excludes the electric signal that commands the stoppage and cancellation of the inflow of water, it is possible to test the operation of the level switch even while the plant is operating, so that it is possible to prevent the plant from stopping due to a malfunction of the level switch. Alternatively, it is possible to prevent problems in turbine operation due to an excessive rise in the water level in the moisture separator due to malfunction of the level switch, and this can contribute to improving the reliability and safety of the entire plant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a test device for a moisture separator level switch according to the present invention, and FIG. 2 is a circuit diagram showing an example of a circuit that automatically performs a test in a testing device of an incorrect embodiment. 3 are block diagrams showing another embodiment of the present invention, and FIG. 4 is a circuit diagram similar to FIG. 2 of another embodiment. 1...Compressed air, 2...Solenoid valve, 4.
...Air cylinder, 5...Water level rise position limit switch, 6...Water level lower limit position limit switch, T...Rod, 8...
Level switch body, 9...Float, 10.
... link mechanism, 12 ... moisture separator,
20... Level switch, 35... Electromagnetic solenoid.

Claims (1)

[Claims] 1 A moisture separator that separates the moisture contained in the medium passing through the vessel, a float that moves up and down in response to the level of moisture stored as drain in this moisture separator, and a container that houses this float. a level switch body having a means for communicating with a position for storing drain of the moisture separator, and a means for stopping and releasing the flow of the medium passing through the moisture separator at the upper and lower limit positions of the float; A testing device for a moisture separator level switch, comprising an electric signal generating means for commanding, a moving means for moving the float up and down based on an operation signal, and upper and lower limits of the float that is moved up and down by the moving means. a moisture separator level switch testing device, characterized in that the test device for a moisture separator level switch is provided with another electric signal generating means for excluding an electric signal instructing the stoppage and cancellation of the flow of the medium passing through the moisture separator.