Radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor

Abstract

The invention discloses an irradiation-resistant and high-temperature-resistant dual-redundancy pressure sensor, belongs to the technical field of sensor manufacturing, and aims to solve the problem that the pressure of a highly-corrosive metal coolant is difficult to measure in a high-temperature irradiation environment. A pressure sensing cavity is used for containing a medium to be measured, a pressure sensing assembly obtains the pressure difference between the pressure sensing cavity and a vacuum cavity in a sensing mode and transmits the pressure difference to a force measuring ring through a center connecting rod, the force measuring ring generates deformation quantity, the center connecting rod generates displacement, and an iron core of the LVDT is driven to deviate from a middle point. A secondary coil of the differential transformer LVDT generates unequal induced electromotive force so as to generate output voltage; the dynamometer ring and the differential transformer LVDT realize dual-redundancy measurement of pressure parameters. The cooling device is used for cooling the nuclear reactor.

Description

Technical Field

[0001] The present invention relates to a radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor, belonging to the technical field of sensor manufacturing. Background Art

[0002] The coolant of a nuclear reactor refers to the working medium used to cool the core of the nuclear reactor and carry out the heat released by the core out of the nuclear reactor, also known as the heat carrier. In addition to the heat generated by the nuclear fission of nuclear fuel, other components also generate heat due to the absorption of γ-rays and moderation of neutrons. Therefore, appropriate cooling is also required for related components, in-core structures, reflectors, shielding layers, etc.

[0003] In the nuclear field, high-temperature sodium-potassium and lead-bismuth high-temperature liquid alloys are commonly used as the coolant for the reactor core. Due to different design characteristics and operating requirements of different types of reactors, the working pressure of the coolant also varies. The working pressure of the coolant directly affects the working state of the reactor core and is an important parameter of the reactor cooling system.

[0004] However, due to its high temperature, irradiation environment and strong corrosiveness of liquid metal, it is difficult to measure the pressure. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of difficult pressure measurement of strongly corrosive metal coolants in a high-temperature irradiation environment, and provide a radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor.

[0006] The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor of the present invention includes:

[0007] The pressure sensing cavity is used to hold the medium to be measured. The pressure sensing component senses the pressure difference between the pressure sensing cavity and the vacuum cavity, transmits the pressure difference to the force measuring ring through the central connecting rod. The force measuring ring generates a deformation, the central connecting rod generates a displacement, driving the iron core of the differential transformer LVDT to deviate from the middle point, and the secondary coil of the differential transformer LVDT generates unequal induced electromotive forces, thereby generating an output voltage;

[0008] The force measuring ring and the differential transformer LVDT achieve dual-redundancy measurement of pressure parameters.

[0009] Preferably, strain gauges are arranged on the force measuring ring, and the strain gauges generate deformations through the strain at the sensitive part.

[0010] Preferably, the strain value ε of the strain gauge on the force measuring ring is:

[0011]

[0012] The deflection f at both ends of the force measuring ring is:

[0013]

[0014] Among them, F represents the applied load, R represents the average radius, E represents the elastic modulus, a represents the width, and e represents the thickness;

[0015] The maximum force value of the force measuring ring is:

[0016] σ max = Eε.

[0017] Preferably, the maximum displacement of the iron core of the differential transformer LVDT from the midpoint is 0.8 mm.

[0018] Preferably, both the pressure sensing cavity and the vacuum cavity are vacuum sealed cavities;

[0019] The pressure sensing cavity is used to place the force measuring ring and the differential transformer LVDT in a vacuum sealed cavity composed of a metal shell, a bellows, and a sintered tube seat;

[0020] The vacuum cavity is used to isolate the pressure sensing bellows from the medium.

[0021] Preferably, the stiffness K of the bellows = 3.34 N / mm; the effective area A = 5.62 cm 2 ;

[0022] The load F under full scale action 0 is:

[0023] F 0 = PA;

[0024] Among them, P represents the full scale pressure.

[0025] Preferably, a heating ring and a thermocouple are arranged outside the pressure sensing cavity. The temperature of the pressure sensing cavity is detected in real time by the thermocouple. When the temperature is lower than the solidification temperature point of the metal medium, the heating ring is used for heating.

[0026] Preferably, a limiting nut is arranged on the central connecting rod to limit the overload pressure.

[0027] Preferably, the differential transformer LVDT adopts a three-section solenoid coil.

[0028] Advantages of the present invention: The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor proposed by the present invention uses a force measuring ring and a differential transformer to achieve dual-redundancy pressure measurement, and has the characteristics of high temperature resistance and radiation resistance. It can realize the pressure measurement of the high-temperature and strongly corrosive liquid metal coolant in the reactor core. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of the radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor of the present invention;

[0030] Figure 2It is the principle block diagram of the radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor of the present invention;

[0031] Figure 3 It is the schematic diagram of the sensitive element of the radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor of the present invention;

[0032] Figure 4 It is the structural schematic diagram of the force-measuring ring of the present invention;

[0033] Figure 5 It is the structural schematic diagram of the bellows of the present invention;

[0034] Figure 6 It is the equivalent principle block diagram of the differential transformer LVDT of the present invention;

[0035] Figure 7 It is the schematic diagram of the three-section solenoid coil of the differential transformer LVDT of the present invention. Specific embodiments

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0038] Next, the present invention will be further described in conjunction with the accompanying drawings and specific embodiments, but it is not a limitation of the present invention.

[0039] Embodiment 1:

[0040] Next, in conjunction with Figures 1-7 This embodiment will be described. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor described in this embodiment includes:

[0041] The pressure sensing cavity is used to hold the medium to be measured. The pressure sensing component senses the pressure difference between the pressure sensing cavity and the vacuum cavity, transmits the pressure difference to the force-measuring ring through the central connecting rod. The force-measuring ring generates a deformation, and the central connecting rod generates a displacement, driving the iron core of the differential transformer LVDT to deviate from the midpoint. The secondary coils of the differential transformer LVDT generate unequal induced electromotive forces, and then an output voltage is generated;

[0042] The force-measuring ring and the differential transformer LVDT realize the dual-redundancy measurement of pressure parameters.

[0043] Further, a strain gauge is provided on the force measuring ring, and the strain gauge generates a deformation due to the strain at the sensitive part.

[0044] Still further, the strain value ε of the strain gauge on the force measuring ring is:

[0045]

[0046] The deflection f at both ends of the force measuring ring is:

[0047]

[0048] Wherein, F represents the applied load, R represents the average radius, E represents the elastic modulus, a represents the width, and e represents the thickness;

[0049] The maximum force value of the force measuring ring is:

[0050] σ max = Eε.

[0051] Still further, the maximum displacement of the iron core of the differential transformer LVDT deviating from the midpoint is 0.8 mm.

[0052] Still further, both the pressure sensing chamber and the vacuum chamber are vacuum sealed chambers;

[0053] The pressure sensing chamber is used to place the force measuring ring and the differential transformer LVDT in a vacuum sealed chamber composed of a metal shell, a bellows, and a sintered tube seat;

[0054] The vacuum chamber is used to isolate the pressure sensing bellows from the medium.

[0055] Still further, the stiffness K of the bellows is 3.34 N / mm; the effective area A is 5.62 cm 2 ;

[0056] The load F under full scale operation 0 is:

[0057] F 0 = PA;

[0058] Wherein, P represents the full scale pressure.

[0059] Still further, a heating ring and a thermocouple are provided outside the pressure sensing chamber. The temperature of the pressure sensing chamber is detected in real time by the thermocouple, and when the temperature is lower than the solidification temperature point of the metal medium, the heating ring is used for heating.

[0060] Still further, a limit nut is provided on the central connecting rod to limit the overload pressure.

[0061] Still further, the differential transformer LVDT adopts a three-section solenoid coil.

[0062] In the present invention, a radiation-resistant high-temperature dual-redundancy pressure sensor mainly consists of an electrical connector, a circuit component, a sintered socket, a force-measuring ring, an overload protection nut, a linear variable differential transformer (LVDT), a vacuum chamber, a heating ring, a pressure-sensing chamber and other components. Its characteristics are as follows: the force-measuring ring and the differential transformer are used to achieve dual-redundancy measurement of pressure parameters. As Figure 1 shown.

[0063] The pressure-sensing chamber uses a corrugated component to achieve medium isolation. Under the action of the medium pressure, the bellows transfers the pressure to the force-measuring ring through the core rod. The force-measuring ring generates strain under the action of the core rod, and the pressure measurement is realized by measuring the strain at the sensitive part of the force-measuring ring.

[0064] The iron core of the differential transformer is connected to the core rod. Under the action of the medium pressure, the core rod moves with the force-measuring ring by a maximum displacement of 0.8 mm. The change in the position of the iron core causes a change in the output of the differential transformer. The output is linearly related to both the displacement of the iron core and the magnitude of the pressure. Detecting the output of the differential transformer can achieve pressure testing.

[0065] The product has two vacuum chambers. The force-measuring ring and the differential transformer are located in the vacuum chamber 1 composed of a metal shell, a bellows and a sintered socket. The sealed space is a vacuum environment, which avoids the contact between the internal components and the external air, and improves the service life of the product. The vacuum chamber 2 is isolated from the medium through the pressure-sensing bellows and serves as a pressure-sensing reference chamber.

[0066] A heating ring and a thermocouple are installed outside the pressure-sensing chamber, which can detect the temperature of the pressure-sensing chamber in real time and can heat through the heating ring to avoid the solidification of the metal medium in the pressure-sensing chamber.

[0067] The limit nut can limit the displacement of the core rod to avoid structural damage caused by overload pressure.

[0068] The working principle of this pressure sensor is as follows: as Figure 2 shown, using the pressure difference between the sodium-potassium alloy in the pressure-sensing chamber and the reference vacuum chamber, the free end of the pressure-sensing component transfers the force to the force-measuring ring through the central connecting rod. The magnitude of this force is measured by strain electrical measurement technology and is linearly related to the pressure in the pressure-sensing chamber. This force causes the force-measuring ring to produce a corresponding deformation, and the central rod generates a certain displacement. With the help of the iron core connecting rod structure, the iron core in the vacuum-isolated differential transformer deviates from the midpoint, resulting in unequal induced electromotive forces in the two secondary coils of the differential transformer, generating an output voltage. The output voltage is linearly corresponding to the change in the displacement of the iron core.

[0069] As Figure 3As shown, the sensor relies on the front-end sealed bellows to transfer pressure to the force measuring ring. Strain gauges are attached to the force measuring ring to sense the strain of the force measuring ring and output a voltage signal. At the same time, the differential transformer measures the deformation displacement of the force measuring ring. The force measured by the force measuring ring and the displacement measured by the differential transformer are both linearly related to the measured pressure, realizing the dual-redundancy measurement of pressure.

[0070] As Figure 5 shown, the main function of the bellows is to isolate the high-temperature sodium-potassium alloy pressure source from the reference cavity and convert the working pressure effect into a load. The selection of the effective area of the bellows directly determines the size of the load.

[0071] The stiffness K of the bellows is 3.34 N / mm; the effective area A is 5.62 cm 2 ;

[0072] The load F under full-scale action 0 is:

[0073] F 0 = PA = 140.5 N;

[0074] where P represents the full-scale pressure, P = 250 kPa.

[0075] As Figure 6 shown, it is the equivalent principle block diagram of the differential transformer LVDT. Under ideal conditions (neglecting the parasitic capacitance of the coil and the core loss), the equivalent circuit of the LVDT is as Figure 3 shown: where e1 is the excitation voltage of the excitation winding; L1 and R1 are the inductance value and resistance value of the excitation winding; L21 and L22 are the inductance values of the left and right output windings; R21 and R22 are the resistance values of the left and right output windings; M1 and M2 are the mutual inductance values between the excitation winding and the left and right output windings respectively. In the initial state, the iron core is in the middle position, and the induced voltage of the secondary coil e1 = e2, then the output voltage U2 = e1 - e2 = 0. When the expansion valve spool drives the iron core to deviate from the middle position, the mutual inductance M of the two coils changes. At this time, e1 ≠ e2, U2 ≠ 0, and within a certain range, the displacement is linearly related to the output voltage.

[0076] The LVDT coil is designed as a solenoid type. Although the sensitivity of this type of LVDT is relatively low, its indication range is large, the free stroke can be arranged arbitrarily, and the manufacturing and assembly are relatively convenient. Therefore, it has the widest application. The common coil arrangement forms of the solenoid type LVDT are one-section type, two-section type, and three-section type. The one-section type has high sensitivity, but the zero voltage of the three-section type is smaller. Therefore, the three-section type coil is selected, as Figure 7 is the schematic diagram of the three-section solenoid coil of the differential transformer LVDT.

[0077] Figure 4 is the structural schematic diagram of the force measuring ring. The strain value ε of the strain gauge of the force measuring ring is:

[0078]

[0079] The deflections f at both ends of the force measuring ring are as follows:

[0080]

[0081] The maximum force value of the force measuring ring is:

[0082] σ max = Eε = 218 N / mm 2 ;

[0083] 218 N / mm 2 <1260 N / mm 2 , meeting the strength requirements.

[0084] The sensor sensitivity is:

[0085] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Accordingly, it should be understood that numerous modifications may be made to the exemplary embodiments, and other arrangements may be designed, provided that the spirit and scope of the present invention as defined by the appended claims are not departed from. It should be understood that the different dependent claims and the features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a separate embodiment may be used in other described embodiments.

Claims

1. A radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor, characterized in that: It includes: The pressure-sensing chamber is used to hold the medium to be tested. The pressure-sensing component senses the pressure difference between the pressure-sensing chamber and the vacuum chamber, and transmits the pressure difference to the force-measuring ring through the central connecting rod. The force-measuring ring generates a deformation variable, and the central connecting rod generates a displacement, which drives the iron core of the differential transformer LVDT to deviate from the middle point. The secondary coil of the differential transformer LVDT generates unequal induced electromotive force, and then generates an output voltage; The force measuring ring and the differential transformer LVDT realize dual-redundancy measurement of pressure parameters.

2. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 1, characterized in that: The force measuring ring is provided with a strain gauge, which generates a deformation amount through the strain at the sensitive part.

3. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 2, characterized in that: The strain value ε of the strain gauge of the force measuring ring is: The deflection f at both ends of the force measuring ring is: Where F represents the applied load, R represents the average radius, E represents the elastic modulus, a represents the width, and e represents the thickness; The maximum force of the force measuring ring is: s max =Ee.

4. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 1, characterized in that: The maximum displacement of the core of the differential transformer LVDT from the midpoint is 0.8 mm.

5. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 1, characterized in that: The pressure-sensing cavity and the vacuum cavity are both vacuum-sealed cavities; The pressure sensing chamber is used to place the force measuring ring and the differential transformer LVDT in a vacuum sealed chamber formed by a metal shell, a bellows and a sintered tube seat; The vacuum chamber is used to isolate the pressure-sensitive bellows from the medium.

6. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 1, characterized in that: The stiffness of the bellows is K = 3.34 N / mm; the effective surface A = 5.62 cm 2 ; The load F0 under full scale is: F0=PA; Wherein, P represents the full scale pressure.

7. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 1, characterized in that: A heating ring and a thermocouple are arranged outside the pressure sensing chamber, and the temperature of the pressure sensing chamber is detected in real time by the thermocouple. When the temperature is lower than the solidification temperature of the metal medium, the heating ring is used for heating.

8. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 1, characterized in that: A limit nut is arranged on the central connecting rod to limit the overload pressure.

9. The radiation-resistant and high-temperature-resistant dual-redundancy pressure sensor according to claim 7, characterized in that: The differential transformer LVDT adopts a three-section solenoid coil.

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