CN115691845A

CN115691845A - Temperature and humidity sensor for monitoring leakage of coolant in nuclear power station

Info

Publication number: CN115691845A
Application number: CN202211318820.6A
Authority: CN
Inventors: 杨勇; 程蜀炜; 高虎; 郭潜; 乔宗璞; 王万海; 崔小强; 王瑞; 赵乾; 张凯
Original assignee: Lianyungang Jierui Electronics Co Ltd
Current assignee: Lianyungang Jierui Electronics Co Ltd
Priority date: 2022-10-26
Filing date: 2022-10-26
Publication date: 2023-02-03

Abstract

The invention discloses a temperature and humidity sensor for monitoring leakage of a nuclear power station coolant, which is mainly used for detecting the air temperature and humidity change between the outer surface of a main pipeline and the inner surface of an insulating layer, carrying out online detection on the sealing performance of a primary circuit of a reactor device, and judging the leakage condition of the coolant through the abnormal change of the temperature and the humidity when the coolant leaks. The temperature and humidity sensor consists of a remote probe, a transmission cable and a signal processing module. The remote probe is placed in a loop in which the coolant is likely to leak, and is connected to a signal processing module in a control room, which is several tens to several hundreds of meters away, through a cable, and the signal processing module performs signal conversion, filtering and amplification processing on the remote probe, and finally outputs voltage signals related to temperature and humidity. The temperature and humidity sensor can effectively realize the on-line detection of the coolant leakage condition which possibly occurs when the nuclear reactor operates, and is stable and reliable.

Description

Temperature and humidity sensor for monitoring leakage of coolant in nuclear power station

Technical Field

The invention belongs to the technical field of auxiliary monitoring of nuclear power stations, and particularly relates to a temperature and humidity sensor for monitoring leakage of a coolant of a nuclear power station.

Background

In the past, nuclear energy as an efficient and clean energy has the ability to play an important role of no alternatives in responding to energy challenges, and meanwhile, how to ensure the safety of nuclear power is one of the hot spots of people's attention. In the operation of the nuclear power plant, a plurality of auxiliary monitoring devices are provided for discovering abnormal conditions in time and processing the abnormal conditions in time so as to ensure the operation safety of the nuclear power plant. It is desirable to detect a primary coolant leak in a nuclear reactor plant circuit in a normal operating mode, a failure mode, and a "small" makeup coolant leak mode when operating the power unit at different power levels.

In the field of chemical plants, processing plants and the like, digital temperature and humidity sensors are generally used for detecting leakage of pipeline gas and liquid, and the sensors are integrated chips, directly output voltage or digital signals related to environmental changes, and then connect the output signals to a processing module of a monitoring room through a long line for further processing. The integrated chip temperature and humidity sensor is directly used, is simple and reliable to install and debug and is suitable for most industrial occasions, but has the defects that the integrated chip temperature and humidity sensor is an active device, nuclear radiation resistance is difficult to achieve, and the integrated chip temperature and humidity sensor cannot be normally used in a nuclear radiation environment. When nuclear reactor coolant leaks, nuclear radiation may occur, so direct use of an integrated chip-based temperature and humidity sensor is not feasible.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provide a temperature and humidity sensor for monitoring leakage of coolant in a nuclear power station.

The technical solution for realizing the purpose of the invention is as follows: the temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power station comprises a remote probe, a transmission cable and a signal processing module, wherein the remote probe is arranged in a loop in which the coolant is likely to leak, namely the loop to be monitored, and is connected to the signal processing module in a control room with the length ranging from dozens of meters to hundreds of meters through the transmission cable, and the signal processing module is used for carrying out signal conversion, filtering and amplification processing on the remote probe and outputting voltage signals related to temperature and humidity.

Furthermore, the remote probe comprises a shell, and a humidity-sensitive capacitor, a thermistor, an internal circuit board and a cable which are arranged in the shell, wherein the internal circuit board comprises a reference resistor, a reference capacitor and a micro relay and is used for realizing the switching of the self-checking function; when the temperature and humidity sensor is in a self-checking state, the signal processing module supplies power to the micro relay, the micro relay is closed, the thermistor and the humidity sensitive capacitor are switched to the nominal reference resistor and reference capacitor on the circuit board, and whether devices, wiring and a signal processing circuit of the temperature and humidity sensor are abnormal or not is judged by reading the values of the reference resistor and the reference capacitor.

Further, the signal processing module comprises a thermistor signal processing circuit and a humidity-sensitive capacitor signal processing circuit;

the thermistor signal processing circuit specifically comprises: converting the thermistor signal into a direct-current voltage signal, performing primary voltage amplification, isolating the voltage signal from a primary amplifying circuit, filtering the isolated voltage, performing secondary voltage amplification, and outputting a final voltage signal related to temperature;

the humidity-sensitive capacitor signal processing circuit specifically comprises: performing primary amplification on the humidity-sensitive capacitor signal to obtain amplified alternating current harmonic, wherein the amplitude of the alternating current harmonic is in direct proportion to the capacitance value of the humidity-sensitive capacitor; then isolating the alternating current harmonic wave, converting the alternating current harmonic wave into a direct current signal, and then filtering; and finally, performing secondary amplification on the voltage, and outputting a final voltage signal related to the humidity.

Furthermore, the thermistor signal processing circuit comprises a constant current source, a first primary amplification circuit, a first signal current isolation circuit, a second-order filtering and biasing circuit and a second-order amplification circuit;

the constant current source comprises a constant current source chip, the first primary amplification circuit comprises an instrument amplifier and a first resistor, the first signal current isolation circuit comprises a signal current isolation chip, and the second-order filtering and biasing circuit comprises a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first slide rheostat, a first capacitor and a second capacitor; the second-stage amplification circuit comprises a first operational amplifier, a seventh resistor, an eighth resistor, a second slide rheostat and a third capacitor;

one end of the thermistor is grounded, the other end of the thermistor is connected with a pin 7 and a pin 8 of the constant current source chip and a pin 2 of the instrumentation amplifier, and simultaneously, the thermistor is grounded through a capacitor, and a pin 3 and a pin 6 of the constant current source chip are respectively connected with-12V and +12V voltages; pin 1 of the instrumentation amplifier is connected with pin 8 thereof through a first resistor, pin 7 and pin 4 of the instrumentation amplifier are respectively connected with +12V and-12V voltages, pin 5 is grounded, pin 6 is connected with pin 15 of the signal galvanic isolation chip, pin 1 and pin 9 of the signal galvanic isolation chip are connected with +12V voltages, pin 2 and pin 10 are connected with-12V voltages, pin 8 and pin 16 are grounded, pin 7 is connected with pin 3 of the first operational amplifier through a fifth resistor and a sixth resistor which are connected in series, the common end of the fifth resistor and the sixth resistor is grounded through a first capacitor, the common end of the sixth resistor and pin 3 of the first operational amplifier is grounded through a second capacitor, and is simultaneously connected with the sliding end of the first slide rheostat through a fourth resistor, one fixed end of the first slide rheostat is connected with +12V voltages through a second resistor, and the other fixed end is connected with-12V voltages through a third resistor; the pin 2 of the first operational amplifier is grounded through an eighth resistor and is simultaneously connected with the pin 6 of the first operational amplifier through a third capacitor, a seventh resistor and a second slide rheostat which are connected with the third capacitor in parallel and are connected in series are arranged between the pin 2 and the pin 6 of the first operational amplifier, the sliding end of the second slide rheostat is connected with the pin 6 of the first operational amplifier, and the pin 7 and the pin 4 of the first operational amplifier are respectively connected with voltages of +12V and-12V.

Furthermore, the humidity-sensitive capacitance signal processing circuit comprises an alternating current harmonic circuit, a second primary amplifying circuit, a second signal current isolating circuit, a detection circuit, a second-order filtering circuit and a second-order amplifying circuit;

the alternating current harmonic circuit comprises an alternating current harmonic isolation transformer and a humidity sensitive capacitor; the second primary amplifying circuit comprises a second operational amplifier, a fourth capacitor and a ninth resistor; the second signal current isolation circuit comprises a signal isolation transformer and a fifth capacitor; the detection circuit comprises a third operational amplifier, a tenth resistor, an eleventh resistor, a first diode and a second diode; the second-order filtering and second-order amplifying circuit comprises a fourth operational amplifier, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a third slide rheostat, a fourth slide rheostat, a sixth capacitor, a seventh capacitor and an eighth capacitor;

the primary side of the alternating current harmonic isolation transformer is connected with an alternating current power supply, one end of the secondary side of the alternating current harmonic isolation transformer is grounded, the other end of the secondary side of the alternating current harmonic isolation transformer is connected with a pin 2 of a second operational amplifier through a humidity-sensitive capacitor, the pin 2 is connected with a pin 6 of the second operational amplifier through a fourth capacitor and a ninth resistor which are connected in parallel, a pin 3 of the second operational amplifier is grounded, and a pin 7 and a pin 4 of the second operational amplifier are respectively connected with +12V and-12V voltages; a pin 6 of the second operational amplifier is connected with one end of a primary side of the signal isolation transformer through an electrolytic capacitor, the other end of the primary side is grounded, two ends of a secondary side of the signal isolation transformer are connected and grounded through a fifth capacitor, one end of the secondary side of the signal isolation transformer is connected with a pin 2 of the third operational amplifier through a sixteenth resistor, the pin 2 is connected with the pin 6 of the third operational amplifier through a tenth resistor and a first diode which are connected in series, and is connected with the pin 6 of the third operational amplifier through an eleventh resistor and a second diode which are connected in series, wherein the negative electrode of the first diode and the positive electrode of the second diode are connected with the pin 6 of the third operational amplifier; pin 3 of the third operational amplifier is grounded, and pin 7 and pin 4 are respectively connected with +12V and-12V voltages; the common end of the tenth resistor and the first diode is connected with a pin 3 of the fourth operational amplifier through a twelfth resistor and a thirteenth resistor which are connected in series, the pin 3 is grounded through a seventh capacitor, and the common end of the twelfth resistor and the thirteenth resistor is grounded through a sixth capacitor; the pin 2 of the fourth operational amplifier is grounded through a fourteenth resistor, is connected with the pin 6 of the fourth operational amplifier through a fifteenth resistor and a third slide rheostat which are connected in series, and is simultaneously connected with the pin 6 of the fourth operational amplifier through an eighth capacitor, wherein the sliding end of the third slide rheostat is connected with the pin 6; pin 1 of the fourth operational amplifier is connected with pin 8 thereof through a fourth sliding rheostat, the sliding end of the fourth sliding rheostat and pin 7 of the fourth operational amplifier are connected with +12V voltage, and pin 4 of the fourth operational amplifier is connected with-12V voltage.

Compared with the prior art, the invention has the following remarkable advantages:

1) The temperature and humidity sensor used by the invention is a thermistor and a humidity sensitive capacitor which are passive devices and are not influenced by nuclear radiation irradiation, and can work normally, stably and reliably in a nuclear radiation environment possibly existing when a nuclear reactor coolant leaks.

2) The thermistor uses constant current source power supply, and the constant current source power supply can avoid voltage loss on the line and prevent electromagnetic interference. The humidity-sensitive capacitor uses high-frequency alternating current carrier signal transmission, the signal transmission distance is long, and the distortion degree is small.

3) In the process of transmitting the remote signals of the humidity-sensitive capacitor, electromagnetic interference can be possibly caused, and the coaxial shielding cable is used as the cable for transmitting the remote signals of the humidity-sensitive capacitor, so that external interference can be prevented from entering, and the long-distance transmission of the humidity-sensitive capacitor signals without characteristic distortion is realized.

The present invention is described in further detail below with reference to the attached drawing figures.

Drawings

Fig. 1 is a block diagram of a temperature and humidity sensor.

FIG. 2 is a block diagram of the components of the remote probe.

FIG. 3 is a circuit diagram of the internal circuit board of the remote probe.

Fig. 4 is a thermistor signal processing circuit diagram.

FIG. 5 is a circuit diagram of a humidity sensitive capacitor signal processing circuit.

FIG. 6 is an overall cross-sectional view of the remote probe.

Fig. 7 is a partial cross-sectional view of the moisture-sensitive resistor and the thermal capacitor inside the metal cap.

FIG. 8 is a schematic view of the vertical installation of the remote probe

FIG. 9 is a schematic view of a horizontal mounting of the remote probe.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad application.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

In one embodiment, referring to fig. 1, a temperature and humidity sensor for monitoring leakage of coolant in a nuclear power plant is provided, which includes a remote probe, a transmission cable, and a signal processing module, wherein the remote probe is placed in a loop where coolant may leak, i.e., a loop to be monitored, and is connected to the signal processing module in a control room, which is several tens to several hundreds of meters away, through the transmission cable, and the signal processing module performs signal conversion, filtering and amplification processing on the remote probe, and outputs a voltage signal related to temperature and humidity.

Further, in one embodiment, referring to fig. 2, the remote probe comprises a housing, and a humidity-sensitive capacitor, a thermistor, an internal circuit board and a cable arranged in the housing, wherein the internal circuit board comprises a reference resistor, a reference capacitor and a micro relay for switching the self-checking function. The schematic diagram of the internal circuit board is shown in fig. 3, wherein U1 is a micro relay, R1 is a reference resistor, C3 is a reference capacitor, R2 is a thermistor, and C4 is a humidity sensitive capacitor. When the temperature and humidity sensor is in a self-checking state, the signal processing module supplies power to the micro relay coil, the micro relay is closed, the thermistor and the humidity sensitive capacitor are switched to the reference resistor and the reference capacitor on the circuit board, and the values of the reference resistor and the reference capacitor are read to judge whether devices, wiring and a signal processing circuit of the temperature and humidity sensor are abnormal or not.

In fig. 1, 1 and 2 are thermistor connections, 3 and 4 are micro relay connections, 5 and 7 are humidity-sensitive capacitor coaxial shielding layers, and 6 and 8 are humidity-sensitive capacitor connections. Preferably, the two wires of the humidity-sensitive capacitor use coaxial shielding cables to prevent interference signals from entering, and long-distance transmission of humidity-sensitive capacitor signals without characteristic distortion is realized.

Further, in one embodiment, the signal processing module comprises a thermistor signal processing circuit and a humidity-sensitive capacitor signal processing circuit;

(1) The thermistor signal processing circuit is shown in fig. 4, the thermistor is powered by a constant current source of 500uA and converted into a direct current voltage signal, the voltage is amplified by a primary amplifier, and then the voltage is isolated from the primary circuit by a voltage isolation chip. The isolated voltage is filtered by a second-order filter circuit, the signal voltage is amplified to a proper value by a second-order amplifying circuit, and the finally output voltage is linearly related to the environment temperature of the thermistor.

Specifically, the thermistor signal processing circuit comprises a constant current source, a first primary amplification circuit, a first signal current isolation circuit, a second-order filtering and biasing circuit and a second-order amplification circuit;

the constant current source comprises a constant current source chip U1, the first primary amplification circuit comprises an instrument amplifier U2 and a first resistor R101, the first signal current isolation circuit comprises a signal current isolation chip U3, and the second-order filtering and biasing circuit comprises a second resistor R201, a third resistor R202, a fourth resistor R1, a fifth resistor R301, a sixth resistor R302, a first slide rheostat RP1, a first capacitor C33 and a second capacitor C34; the two-stage amplification circuit comprises a first operational amplifier U4, a seventh resistor R401, an eighth resistor R501, a second slide rheostat RP3 and a third capacitor C35;

one end of the thermistor is grounded, the other end of the thermistor is connected with a pin 7 and a pin 8 of the constant current source chip and a pin 2 of the instrumentation amplifier U2, and the thermistor is grounded through a capacitor C201, and a pin 3 and a pin 6 of the constant current source chip are respectively connected with-12V and +12V voltages; pin 1 of an instrumentation amplifier U2 is connected with pin 8 thereof through a first resistor R101, pin 7 and pin 4 of the instrumentation amplifier U2 are respectively connected with +12V and-12V voltages, pin 5 is grounded, pin 6 is connected with pin 15 of a signal current isolation chip U3, pin 1 and pin 9 of the signal current isolation chip U3 are connected with +12V voltages, pin 2 and pin 10 are connected with-12V voltages, pin 8 and pin 16 are grounded, pin 7 is connected with pin 3 of the first operational amplifier U4 through a fifth resistor R301 and a sixth resistor R302 which are connected in series, a common end of the fifth resistor R301 and a common end of the sixth resistor R302 are grounded through a first capacitor C33, a common end of the sixth resistor R302 and the pin 3 of the first operational amplifier U4 is grounded through a second capacitor C34, and simultaneously connected with a sliding end of the first sliding rheostat RP1 through a fourth resistor R1, one fixed end of the first sliding rheostat RP1 is connected with +12V voltage through a second resistor R201, and the other fixed end is connected with +12V voltage through a third resistor R202-12V voltage; the pin 2 of the first operational amplifier U4 is grounded through an eighth resistor R501, and is simultaneously connected with the pin 6 of the first operational amplifier U4 through a third capacitor C35, a seventh resistor R401 and a second slide rheostat RP3 which are connected with the third capacitor C35 in parallel and are connected in series are simultaneously arranged between the pin 2 and the pin 6 of the first operational amplifier U4, the sliding end of the second slide rheostat RP3 is connected with the pin 6 of the first operational amplifier U4, and the pin 7 and the pin 4 of the first operational amplifier U4 are respectively connected with voltages of +12V and-12V.

(2) The humidity-sensitive capacitor signal processing circuit is shown in fig. 5, the humidity-sensitive capacitor is powered by an alternating current harmonic wave with the frequency of 20KHz and the amplitude of 0.5V, the humidity-sensitive capacitor signal is subjected to a first-stage amplifier to obtain an amplified alternating current harmonic wave, and the amplitude of the alternating current harmonic wave is in direct proportion to the capacitance value of the humidity-sensitive capacitor. Then, after the alternating current harmonic waves are isolated by a signal isolation transformer, the alternating current harmonic waves are rectified into direct current signals through a high-precision detection circuit, and then clutter is filtered through a second-order filter circuit. Finally, the secondary amplifier is used for carrying out bias adjustment and further voltage amplification to obtain final output voltage, and the final output voltage is linearly related to the environmental humidity of the humidity-sensitive capacitor.

Specifically, the humidity-sensitive capacitor signal processing circuit comprises an alternating current harmonic circuit, a second first-stage amplification circuit, a second signal current isolation circuit, a detection circuit, a second-order filtering circuit and a second-stage amplification circuit;

the alternating current harmonic circuit comprises an alternating current harmonic isolation transformer T1 and a humidity sensitive capacitor; the second-stage amplifying circuit comprises a second operational amplifier U5, a fourth capacitor C301 and a ninth resistor R2; the second signal current isolation circuit comprises a signal isolation transformer T2 and a fifth capacitor C401; the detection circuit comprises a third operational amplifier U6, a tenth resistor R601, an eleventh resistor R801, a first diode D1 and a second diode D2; the second-order filtering and second-order amplifying circuit comprises a fourth operational amplifier U7, a twelfth resistor R901, a thirteenth resistor R502, a fourteenth resistor R701, a fifteenth resistor R204, a third slide rheostat RP4, a fourth slide rheostat RP7, a sixth capacitor C36, a seventh capacitor C37 and an eighth capacitor C38;

the primary side of the alternating current harmonic isolation transformer T1 is connected with an alternating current power supply, one end of the secondary side is grounded, the other end of the secondary side is connected with a pin 2 of a second operational amplifier U5 through a humidity-sensitive capacitor, the pin 2 is connected with a pin 6 of the second operational amplifier U5 through a fourth capacitor C301 and a ninth resistor R2 which are connected in parallel, a pin 3 of the second operational amplifier U5 is grounded, and a pin 7 and a pin 4 are respectively connected with +12V and-12V voltages; a pin 6 of the second operational amplifier U5 is connected to one end of a primary side of the signal isolation transformer T2 through an electrolytic capacitor C103, the other end of the primary side is grounded, two ends of a secondary side of the signal isolation transformer T2 are connected and grounded through a fifth capacitor C401, one end of the secondary side is connected to a pin 2 of the third operational amplifier U6 through a sixteenth resistor R203, the pin 2 is connected to the pin 6 of the third operational amplifier U6 through a tenth resistor R601 and a first diode D1 which are connected in series, and is connected to the pin 6 of the third operational amplifier U6 through an eleventh resistor R801 and a second diode D2 which are connected in series, wherein a negative electrode of the first diode D1 and a positive electrode of the second diode D2 are connected to the pin 6 of the third operational amplifier U6; pin 3 of the third operational amplifier U6 is grounded, and pin 7 and pin 4 are respectively connected with +12V and-12V voltages; the common end of the tenth resistor R601 and the first diode D1 is connected with the pin 3 of the fourth operational amplifier U7 through a twelfth resistor R901 and a thirteenth resistor R502 which are connected in series, the pin 3 is grounded through a seventh capacitor C37, and the common end of the twelfth resistor R901 and the thirteenth resistor R502 is grounded through a sixth capacitor C36; pin 2 of the fourth operational amplifier U7 is grounded through a fourteenth resistor R701, and is connected to pin 6 of the fourth operational amplifier U7 through a fifteenth resistor R204 and a third sliding rheostat RP4 which are connected in series, and is connected to pin 6 of the fourth operational amplifier U7 through an eighth capacitor C38, wherein a sliding end of the third sliding rheostat RP4 is connected to pin 6; the pin 1 of the fourth operational amplifier U7 is connected with the pin 8 thereof through a fourth slide rheostat RP7, the slide end of the fourth slide rheostat RP7 and the pin 7 of the fourth operational amplifier U7 are connected with +12V voltage, and the pin 4 of the fourth operational amplifier U7 is connected with-12V voltage.

Further, in one embodiment, referring to fig. 6, the remote probe is mounted on a probe base on the detected pipeline, located at the detected position, and includes a metal protection cap 1, a thermistor 2, a humidity sensitive capacitor 15, a pin assembly, a wire conduit 4, a probe circuit board 8, a probe housing 7, an upper cover 9 and a wire conduit; a metal protective cap is sleeved outside one end of the pin insertion assembly, a thermistor and a humidity sensitive capacitor are arranged inside the metal protective cap, and a cable is arranged at the other end of the metal protective cap, inserted into the wiring pipe and fixedly connected with one end of the wiring pipe; the other end of the wiring pipe is fixedly connected with the lower end of the probe shell, an upper cover is arranged at an opening at the upper end of the probe shell, the wiring pipe, the probe shell and the upper cover form a probe inner cavity, a probe circuit board is arranged in the cavity of the probe shell and used for judging whether devices, wiring and a signal processing circuit of the thermistor and the humidity-sensitive capacitor are abnormal or not and transmitting detected temperature and humidity signals to an external signal processing module; the side wall of the probe shell is provided with a wire outlet pipe for placing a transmission cable between the probe and an external signal processing module thereof; when the probe works, the metal protective cap, the thermistor and the humidity sensitive capacitor inside the metal protective cap are completely arranged in a monitoring environment. And the probe inner cavity formed by the wiring pipe 4, the probe shell 7 and the upper cover 9 is used for encapsulating and protecting the sealing structure glue 14.

Further, in one embodiment, the remote probe is mounted on the probe base on the pipe to be tested by a probe mounting nut 6 that is sleeved on the outside of the wiring pipe.

Further, in one embodiment, the remote probe further comprises a nut limiting ring 5 sleeved outside the wiring pipe and used for limiting the probe mounting nut 6.

And the probe inner cavity formed by the wiring pipe 4, the probe shell 7 and the upper cover 9 is used for encapsulating and protecting the sealing structure glue 14.

Further, in one embodiment, referring to fig. 6 and 7, the pin assembly 3 includes a gold-plated pin 104, a glass bead 102 and a pin housing 103, wherein the glass bead 102 is formed by sintering the gold-plated pin 104 and the pin housing 103 at a high temperature to form a whole, and the pin is insulated from the housing. One end of the pin housing 103 is provided with an external thread for mounting the metal protection cap 1, and the other end is inserted into the routing tube 4 and fixed with the routing tube 4 by brazing. One side of the gold-plated pin 104 is soldered to the thermistor 2 and the humidity-sensitive capacitor 15, and the other side is soldered to a wiring harness 105 connected to the circuit board.

Further, in one embodiment, with reference to fig. 6 and 7, the metal protection cap 1 is provided with internal threads to be assembled with the pin assembly housing 103, the thermistor 2 and the humidity-sensitive capacitor 15 are disposed in an inner cavity of the metal protection cap 1, a plurality of windows 101 are left on the side surface and the head of the housing of the metal protection cap 1, and the reserved windows 101 ensure that the environment where the thermistor 2 and the humidity-sensitive capacitor 15 are located is consistent with the monitored environment.

Preferably, the metal protection cap is cylindrical, and the windows on the side surface of the shell are uniformly distributed along the cylindrical surface.

Further, in one embodiment, one end of the wiring tube 4 is fixed to the probe housing 7, the other end of the wiring tube is fixed to the pin housing 103, the nut limiting ring 5 is fixed to the outer diameter of the wiring tube 4, and the fixing modes are all hard soldering. The probe mounting nut 6 is sleeved outside the wiring pipe, and the probe mounting nut 6 is mounted with a probe base on the detected pipeline through external threads; the wiring harness 105 inside the probe passes through the wiring tube 4 and is connected with the circuit board 8, and the wiring harness 105 and the circuit board 8 are fixed in a soldering mode.

Further, in one embodiment, the probe housing 7 and the upper cover 9 are installed by internal and external threads, the probe circuit board 8 is fixed in the cavity of the probe housing 7 by using screws, and the probe circuit board 8 includes a reference resistor, a reference capacitor and a micro relay for switching the self-checking function. When the temperature and humidity sensor is in a self-checking state, the signal processing module supplies power to the micro relay, the micro relay is closed, the thermistor and the humidity sensitive capacitor are switched to the nominal reference resistor and reference capacitor on the circuit board, and the values of the reference resistor and the reference capacitor are read to judge whether devices, wiring and a signal processing circuit of the temperature and humidity sensor are abnormal.

Further, in one embodiment, the transmission cable 11 adopts a shielded cable to prevent signal interference; the cable protection tube 12 has a protection effect on the remote transmission cable, the inside of the cable protection tube is a metal corrugated tube, and the outside of the cable protection tube is a layer of heat-shrinkable sleeve; the cable protection tube stabilizing block 10 is fixed with the metal corrugated tube of the cable protection tube 12 in a brazing mode, the cable protection tube locking nut 13 is fixed with the probe shell 7 in a threaded mode, and the cable stabilizing block 10 is limited in the wire outlet tube of the probe shell 7 after the threads are screwed tightly, so that the cable protection tube 12 is fixed.

When the invention is used, the mounting nut 6 is screwed into the pillar of the mounting base on the monitoring point by combining with the figures 8 and 9, the mounting pillar is fixed with the monitored pipeline through a clapboard, a lining plate, a mounting flange and the like on the mounting base, thereby fixing the whole probe at the detected position. The metal protective cap 1, the thermistor 2 and the humidity-sensitive capacitor 15 inside the metal protective cap are arranged in a monitoring environment, so that the thermistor 2 and the humidity-sensitive capacitor 15 can sense the change of the monitoring environment in real time, the humidity-sensitive capacitor 2 is used as a sensitive element to measure relative humidity, and the thermistor 15 is used to measure relative temperature. And a standard resistor and a standard capacitor are arranged in the probe circuit board 8 and are mainly used for periodic self-checking and testing of the channel. When the coolant leaks, the air temperature and the air humidity between the outer surface of the monitored main pipeline and the inner surface of the heat insulation layer change, the resistance value and the capacitance value output by the probe correspondingly change, the signal processing module is used for carrying out signal conversion, filtering and amplification processing on the remote probe, and finally, a related voltage signal is output to calculate and detect the coolant leakage.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and the embodiments and descriptions are only illustrative of the principles of the invention, and any modifications, equivalent substitutions, improvements and the like within the spirit and principle of the invention should be included within the scope of the invention without departing from the spirit and scope of the invention.

Claims

1. The temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power station is characterized by comprising a remote probe, a transmission cable and a signal processing module, wherein the remote probe is arranged in a loop in which the coolant possibly leaks, namely the loop to be monitored, and is connected to the signal processing module in a control room which is dozens of meters to hundreds of meters away through the transmission cable, and the signal processing module is used for carrying out signal conversion, filtering and amplification processing on the remote probe and outputting voltage signals related to temperature and humidity.

2. The temperature and humidity sensor for monitoring leakage of coolant in nuclear power plant according to claim 1, wherein the remote probe comprises a housing, and a humidity-sensitive capacitor, a thermistor, an internal circuit board and a cable which are arranged in the housing, wherein the internal circuit board comprises a reference resistor, a reference capacitor and a micro-relay, and is used for realizing switching of a self-checking function; when the temperature and humidity sensor is in a self-checking state, the signal processing module supplies power to the micro relay, the micro relay is closed, the thermistor and the humidity sensitive capacitor are switched to the nominal reference resistor and reference capacitor on the circuit board, and whether devices, wiring and a signal processing circuit of the temperature and humidity sensor are abnormal or not is judged by reading the values of the reference resistor and the reference capacitor.

3. The temperature and humidity sensor for nuclear power plant coolant leak monitoring of claim 1, wherein the signal processing module includes a thermistor signal processing circuit and a humidity-sensitive capacitance signal processing circuit;

4. The temperature and humidity sensor for monitoring leakage of coolant from nuclear power plants of claim 3, wherein said thermistor signal processing circuit includes a constant current source, a first primary amplification circuit, a first signal galvanic isolation circuit, a second order filtering and biasing circuit, and a second amplification circuit;

the constant current source comprises a constant current source chip (U1), the first primary amplification circuit comprises an instrument amplifier (U2) and a first resistor (R101), the first signal current isolation circuit comprises a signal current isolation chip (U3), and the second-order filtering and biasing circuit comprises a second resistor (R201), a third resistor (R202), a fourth resistor (R1), a fifth resistor (R301), a sixth resistor (R302), a first slide rheostat (RP 1), a first capacitor (C33) and a second capacitor (C34); the two-stage amplification circuit comprises a first operational amplifier (U4), a seventh resistor (R401), an eighth resistor (R501), a second slide rheostat (RP 3) and a third capacitor (C35);

one end of the thermistor is grounded, the other end of the thermistor is connected with a pin 7 and a pin 8 of the constant current source chip and a pin 2 of the instrumentation amplifier (U2), and the thermistor is grounded through a capacitor (C201), and a pin 3 and a pin 6 of the constant current source chip are respectively connected with-12V and +12V voltages; pin 1 of the instrumentation amplifier (U2) is connected with pin 8 thereof through a first resistor (R101), pin 7 and pin 4 of the instrumentation amplifier (U2) are respectively connected with +12V and-12V voltages, pin 5 is grounded, pin 6 is connected with pin 15 of the signal galvanic isolation chip (U3), pin 1 and pin 9 of the signal galvanic isolation chip (U3) are connected with +12V voltage, pin 2 and pin 10 are connected with-12V voltage, pin 8 and pin 16 are grounded, pin 7 is connected with pin 3 of the first operational amplifier (U4) through a fifth resistor (R301) and a sixth resistor (R302) which are connected in series, the common ends of the fifth resistor (R301) and the sixth resistor (R302) are grounded through a first capacitor (C33), the common ends of the sixth resistor (R302) and pin 3 of the first operational amplifier (U4) are grounded through a second capacitor (C34), and the sliding end of the first sliding rheostat (RP 1) is connected with the fixed end of the first sliding rheostat (RP 1) through a second resistor (R201 and a fixed end of the first sliding rheostat (R1) is connected with another fixed end of the first resistor (R12V resistor (R201 and the fixed end of the second rheostat (R12); the pin 2 of the first operational amplifier (U4) is grounded through an eighth resistor (R501), and is simultaneously connected with the pin 6 of the first operational amplifier (U4) through a third capacitor (C35), a seventh resistor (R401) and a second slide rheostat (RP 3) which are connected with the third capacitor (C35) in parallel and are connected in series are arranged between the pin 2 and the pin 6 of the first operational amplifier (U4), the sliding end of the second slide rheostat (RP 3) is connected with the pin 6 of the first operational amplifier (U4), and the pin 7 and the pin 4 of the first operational amplifier (U4) are respectively connected with voltages of +12V and-12V.

5. The temperature and humidity sensor for monitoring leakage of coolant from nuclear power plants as claimed in claim 3, wherein said humidity-sensitive capacitance signal processing circuit includes an AC harmonic circuit, a second first-stage amplification circuit, a second signal galvanic isolation circuit, a detection circuit, and a second-order filtering and second-stage amplification circuit;

the alternating current harmonic circuit comprises an alternating current harmonic isolation transformer (T1) and a humidity sensitive capacitor; the second-stage amplifying circuit comprises a second operational amplifier (U5), a fourth capacitor (C301) and a ninth resistor (R2); the second signal current isolation circuit comprises a signal isolation transformer (T2) and a fifth capacitor (C401); the detector circuit comprises a third operational amplifier (U6), a tenth resistor (R601), an eleventh resistor (R801), a first diode (D1) and a second diode (D2); the second-order filtering and second-order amplifying circuit comprises a fourth operational amplifier (U7), a twelfth resistor (R901), a thirteenth resistor (R502), a fourteenth resistor (R701), a fifteenth resistor (R204), a third sliding rheostat (RP 4), a fourth sliding rheostat (RP 7), a sixth capacitor (C36), a seventh capacitor (C37) and an eighth capacitor (C38);

the primary side of the alternating current harmonic isolation transformer (T1) is connected with an alternating current power supply, one end of the secondary side is grounded, the other end of the secondary side is connected with a pin 2 of a second operational amplifier (U5) through a humidity-sensitive capacitor, the pin 2 is connected with a pin 6 of the second operational amplifier (U5) through a fourth capacitor (C301) and a ninth resistor (R2) which are connected in parallel, a pin 3 of the second operational amplifier (U5) is grounded, and a pin 7 and a pin 4 are respectively connected with +12V and-12V voltages; a pin 6 of a second operational amplifier (U5) is connected with one end of a primary side of a signal isolation transformer (T2) through an electrolytic capacitor (C103), the other end of the primary side is grounded, two ends of a secondary side of the signal isolation transformer (T2) are connected and grounded through a fifth capacitor (C401), one end of the secondary side is connected with a pin 2 of a third operational amplifier (U6) through a sixteenth resistor (R203), the pin 2 is connected with the pin 6 of the third operational amplifier (U6) through a tenth resistor (R601) and a first diode (D1) which are connected in series, and is connected with the pin 6 of the third operational amplifier (U6) through an eleventh resistor (R801) and a second diode (D2) which are connected in series, wherein the negative electrode of the first diode (D1) and the positive electrode of the second diode (D2) are connected with the pin 6 of the third operational amplifier (U6); pin 3 of the third operational amplifier (U6) is grounded, and pin 7 and pin 4 are respectively connected with +12V and-12V voltages; the common end of the tenth resistor (R601) and the first diode (D1) is connected with a pin 3 of a fourth operational amplifier (U7) through a twelfth resistor (R901) and a thirteenth resistor (R502) which are connected in series, the pin 3 is grounded through a seventh capacitor (C37), and the common end of the twelfth resistor (R901) and the thirteenth resistor (R502) is grounded through a sixth capacitor (C36); pin 2 of the fourth operational amplifier (U7) is grounded through a fourteenth resistor (R701), and is connected with pin 6 of the fourth operational amplifier (U7) through a fifteenth resistor (R204) and a third slide rheostat (RP 4) which are connected in series, and is simultaneously connected with pin 6 of the fourth operational amplifier (U7) through an eighth capacitor (C38), wherein the sliding end of the third slide rheostat (RP 4) is connected with pin 6; the pin 1 of the fourth operational amplifier (U7) is connected with the pin 8 thereof through a fourth slide rheostat (RP 7), the slide end of the fourth slide rheostat (RP 7) and the pin 7 of the fourth operational amplifier (U7) are connected with a voltage of +12V, and the pin 4 of the fourth operational amplifier (U7) is connected with a voltage of-12V.

6. The temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power plant as recited in claim 2, wherein the remote probe is mounted on a probe base on the pipeline to be detected, is located at the position to be detected, and comprises a metal protection cap, a humidity-sensitive capacitor, a thermistor, a pin assembly, a wiring tube, an internal circuit board, a probe shell, an upper cover and a wiring tube; a metal protective cap is sleeved outside one end of the pin insertion assembly, a humidity-sensitive capacitor and a thermistor are arranged inside the metal protective cap, and a cable is arranged at the other end of the metal protective cap, inserted into the wiring pipe and fixedly connected with one end of the wiring pipe; the other end of the wiring pipe is fixedly connected with the lower end of the probe shell, an upper cover is arranged at an opening at the upper end of the probe shell, the wiring pipe, the probe shell and the upper cover form an inner cavity of the probe, a sealing structural adhesive is encapsulated in the inner cavity, and an internal circuit board is arranged in a cavity of the probe shell; the side wall of the probe shell is provided with a wire outlet pipe used for placing a transmission cable between the probe and the signal processing module; when the probe works, the metal protective cap, the humidity-sensitive capacitor and the thermistor inside the metal protective cap are completely arranged in a monitoring environment.

7. The temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power plant as claimed in claim 6, wherein the pin assembly includes a gold-plated pin, a glass bead and a pin housing, the gold-plated pin is mounted inside the pin housing through the glass bead to form a whole, the gold-plated pin is insulated from the pin housing, the gold-plated pin is provided with a moisture-sensitive capacitor and a thermistor at one end thereof, and is connected to a cable connected to the internal circuit board at the other end thereof.

8. The temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power plant according to claim 7, wherein a cable protection tube stabilizing block, a cable locking nut and a cable protection tube are arranged in the outlet tube, a metal corrugated tube is arranged in the cable protection tube, and a layer of heat-shrinkable sleeve is arranged outside the cable protection tube; the transmission cable between the remote probe and the signal processing module is arranged in the cable protection pipe, the cable protection pipe stabilizing block is fixed with the metal corrugated pipe of the cable protection pipe, the cable protection pipe locking nut and the probe shell are installed and fixed in a threaded mode, and the cable stabilizing block is limited in the wire outlet pipe of the probe shell after the threads are screwed to fix the transmission cable protection pipe.

9. The temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power plant as claimed in claim 8, wherein the remote probe is mounted on the probe base of the detected pipeline through a probe mounting nut sleeved outside the wiring pipe, and the probe mounting nut is limited through a nut limiting ring sleeved outside the wiring pipe.

10. The temperature and humidity sensor for monitoring the leakage of the coolant in the nuclear power plant as recited in claim 6, wherein a plurality of windows are formed in the side surface and the head of the shell of the metal cap, the metal cap is cylindrical, and the windows on the side surface of the shell are uniformly distributed along the cylindrical surface.