JPH01124744A - Automatic drain for monitor sampling device - Google Patents

Abstract

PURPOSE:To detect the automatic drain being in a bad condition before an influence is exerted on a monitor and to carry on its operation by arranging plural float switches which operate at different water levels. CONSTITUTION:A drain enters a drain pot 14 through a drain intake valve 15 and pooled. When the water level reaches a certain level, the float switch 17 operates and the drain entrance valve 15 is closed while a drain outlet valve 16 is opened, thereby discharging the drain. Then the float switch 17 returns to its original position after the drain is all discharged, and the drain outlet valve 16 is closed while the drain intake valve 15 is opened, so that the drain is injected into the drain pot 14 again. If such abnormality that a float switch 17 of low level fails to operate occurs at this time, a float switch 19 of high level controls the water level of the automatic drain as a substitute for the float switch of low level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an auto-drain for a sample collection device that continuously collects samples in, for example, a radiation gas monitor in a nuclear facility.

[Conventional technology]

Figure 5 shows a process gas with high humidity in a nuclear facility, such as a condenser and an air extractor in a nuclear power plant.

The configuration of a radiation gas monitor used for monitoring the radioactivity of exhaust gas is shown. In the figure, 13 is a pipe through which process gas flows, 1 is a sampling pipe that samples gas from this pipe 13, 2 is a sampling device that sucks the gas and preprocesses it to a state suitable for radiation detection, and 3 is a sample collection device that collects gas in a state suitable for radiation detection. A radiation detector 4 that detects radioactivity is an inter-device piping that connects the sample collection device 2 and the radiation detector 3.

In the sample collecting device 2, 5 is an inlet valve, 6 is a dryer that dehumidifies the sucked gas, 7 is an auto drain that automatically drains the drain generated in the dryer 6, 8 is a filter that removes dust, 9 is a flow meter, 1° is the pressure gauge, 11 is the pump, 1
2 is an outlet valve.

FIG. 6 shows the prior art of the auto drain 7.
In the figure, 14 is a drain bot, 15 is a drain inlet valve,
16 is a drain outlet valve, 17 is a float switch, and 18 is a flow 1-.

Next, the operation of the auto drain 7 will be explained. Drain is collected in the drain bot 14 through the drain inlet valve 15. When the water level reaches a certain level, the float switch 17 is actuated to close the drain inlet valve 15 and open the drain outlet valve 16 to drain water. When draining is completed, the float switch 17 returns to its original position, the drain outlet valve 16 closes, the drain inlet valve 15 opens, and the drain pot 1 closes.
4, the drain is filled with water again.

[Problem that the invention seeks to solve]

Since the conventional auto drain 7 is configured as described above, there is no warning function or backup function in advance for drainage failure caused by water scale adhering to the float switch 17, and the drain does not reach the sample. There was a problem in that it invaded the inside of the sampling device 2 and the radioactivity detector 3, and it took time to recover, resulting in the monitor not being able to take measurements for a long time.

This invention was made in order to solve the above-mentioned problems, and is a monitor sampling device that prevents the monitor from missing readings by utilizing the backup function with one-touch operation before the condensate enters the subsequent stage in case of auto drain abnormality. The purpose is to obtain an auto drain for use.

[Means for solving problems]

The auto drain for a monitor sample collection device according to the present invention includes:
A plurality of float switches, for example two float switches, operating at different water levels, one placed at a lower level where it normally comes into contact with water, and the other placed at an upper level where it normally does not come into contact with water. It is.

[Effect]

In the auto drain of this invention, while the lower level float switch is operating normally, the water level is controlled by the auto drain only by the lower level float switch.6However, the lower level float switch is operating. When an abnormality that causes a failure occurs, a higher level float switch will control the water level of the auto drain instead of this lower level float switch.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows 14 in Figure 0, which is a configuration diagram of the auto drain 7.
15 is a drain pot that collects drain, and 15 is a drain inlet valve.
16 is a drain outlet valve, 17 and 19 are float switches that operate at a set water level, and 18.20 is a float.

Float switch 17 is placed at a lower level that comes into contact with water in normal operation, and float switch 19 is placed at a higher level than float switch 17 so that it does not normally come into contact with water.

Further, FIG. 2 is a control logic diagram for controlling the operation of the auto drain 7 of this embodiment. In the figure, reference numeral 21 denotes a changeover switch, which is used to cancel an alarm that is issued when an abnormality occurs in the float switch 17° or 19. 22 is a selector switch 21 and a float switch 1
23 is an inverter that inverts the output of changeover switch 21, 24 is an AND gate fed with the outputs of float switch 17 and inverter 23, and 25 is an AND gate that receives the outputs of float switch 19 and inverter 23. 26 is an OR gate that receives the outputs of AND gates 22 and 24, 27 is an OR gate that receives the outputs of OR gate 26 and AND gate 28, and 29.30 are timers each operated by the output of OR gate 27. circuit (hereinafter referred to as timer A or timer B), 31 is a timer circuit operated by the output of timer B (hereinafter referred to as timer C)
, 32 inverts the output of timer C31 and outputs AND gate 2.
8, 33 is an inverter that inverts the output of timer A29, 34 is a solenoid valve for drain inlet valve 15 that operates in response to the output of this inverter 34, 35
is a drain outlet valve 1 that operates according to the output of timer B30.
6 is the solenoid valve, 36 is the OR gate 26, and timer C3.
1 is an AND gate that receives the output of 1; 37 is an OR gate that receives the outputs of this AND gate 36 and the AND gate 25;
Reference numeral 38 is a display device that displays an alarm based on the output of the OR gate 37.

Next, the operation will be explained with reference to the time charts of FIGS. 3 and 4. Drain flows into the drain pot 14 via the drain inlet valve 15 and is collected therein.

When the water level in the drain pot 14 reaches the set lower level (time T in FIG. 3), the float switch 17 is activated and its output signal is sent to the timer A29. The signal is applied to timer B30, timer A stops operating, and timer B starts operating. Then, the electromagnetic valves 34 and 35 operate in sequence, the drain inlet valve 15 closes, and the drain outlet valve 16 opens, stopping the flow of drain into the drain pot 14 and draining the drain.

When the timer B times out and draining is completed (time T2 in FIG. 3), the float switch 17 returns to its original position, and the IT solenoid valves 4 and 35 operate in sequence to close the drain outlet valve 1.
6 is closed, and the drain inlet valve 15 is opened again, and the flow of drain into the drain pot 14 is resumed.

As shown from time T in Fig. 3 onward, if a failure occurs in which the float switch 17 does not return to its original position after being turned on and does not turn off, the water level continues to rise again after draining for -degrees, and the upper The level float switch 19 is turned on (time T 4 ).

Therefore, the output signal of the float switch 19 is sent to the display 38 via the AND gate 25 and the OR gate 37.
W information is displayed. Therefore, in this case, when the selector switch 21 is switched to the "on" side, the AND gate 24
, 25 are closed, thereby turning off the indicator 38 and canceling the alarm, and thereafter, the AND gate 22 is opened and the output of the float switch 19 is set to the timer A29. B2
O.

C31 and is also sent to the display 38.

That is, the solenoid valves 34 and 35 are controlled only by the float switch 19 in place of the defective float switch 17, and therefore the drain inlet valve 15 and the drain outlet valve 16 are controlled.

If the float switch 17 becomes defective and remains off, the drain inlet valve 15 remains closed, making it impossible to inject drain into the drain pot 14. In that case (after time T1□ in the time chart of FIG. 4), the state of the float switch 17 after draining water from the drain pot 14 is checked, and an alarm is displayed on the display 38. When the selector switch 21 is turned on, the alarm state is canceled and the float switch 19 then controls the water level in the drain pot 14 instead of the float switch 17, as described above.

As explained above, in the auto drain according to the present invention, since the upper level float switch is not normally in contact with water, it reliably sends a report that enables proactive response to water level abnormalities without having to switch.

Furthermore, after the control is switched, it is possible to start from a state where there is no limescale deterioration, so a highly reliable device can be obtained.

Furthermore, by adding an abnormality detection timer, it is possible to detect an abnormality in the descent of the float, and all abnormalities can be detected together with the detection of an abnormality in the rise by the upper level float switch.

In the above embodiment, an auto drain for a radiation gas monitor sample collection device was shown, but it can also be used for purposes other than radiation gas monitors.

It is particularly effective for use in negative pressure systems or systems where pressure fluctuates significantly and U-seal drainage is generally not applicable.

Further, in the above embodiment, only the alarm display is performed when the float switch is abnormal, but the alarm sound may be emitted instead, or only one of the alarm display and the alarm sound, or even both. may be executed simultaneously.

Further, in the above embodiment, the number of float switches is two, but it is of course possible to provide three or more float switches.

〔Effect of the invention〕

As described above, according to the present invention, an auto drain is configured by including a plurality of float switches, for example, two float switches that operate at different water levels, so auto drain malfunctions can be detected before they affect the monitor. Since operation can be continued by switching control of a defective float switch to control of another normal float switch, a highly reliable monitoring system can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an auto drain for a radiation gas monitor sample collection device according to an embodiment of the present invention, Fig. 2 is a logic circuit diagram for controlling the above embodiment, and Figs. 3 and 4 are alarm and switching diagrams. A timing chart explaining the operation of the switch, FIG. 5 is a configuration diagram of a conventional radiation gas monitor, and FIG. 6 is a sectional view of a conventional auto drain. 14 is a drain pot, 15 is a drain inlet valve, 16 is a drain outlet valve, 17 and 19 are float switches, 29.30
．． 31 indicates a timer circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant Mitsubishi Electric Corporation

Claims (4)

[Claims] (1) The auto drain for the monitor sampling device, which automatically drains the drain generated when continuously sampled humid gas is dehumidified, is equipped with multiple float switches that operate at different water levels of the drain. Features: Auto drain for monitor sample collection device. (2) The water level of one of the float switches is set at a lower level that comes into contact with water during normal operation, and the other
2. The auto drain for a monitor sampling device according to claim 1, wherein the water level of the stand is installed at an upper level that does not normally come into contact with water. (3) The auto drain for a monitor sample collecting device according to claim 1, further comprising a timer circuit that detects an abnormality when the lower level float switch is abnormally lowered. (4) An auto for a monitor sample sampling device according to claim 1, characterized in that when the lower level float switch is abnormal, the operation of the lower level float switch is switched to the higher level float switch. Drain.