SF6 gas density transmitter based on micro-melting sensor

Abstract

The utility model discloses an SF6 gas density transmitter based on a micro-melting sensor, which comprises a filler neck, a shell is mounted on the filler neck, and a connector is mounted at the end part of the shell; wherein the shell is internally provided with a sensor, the sensor is connected with the filler neck, the sensor is connected with the connector through a circuit board, through the arranged sensor, pressure entering the lower end of the filler neck of the transmitter can act on a diaphragm in the micro-melting sensor, the diaphragm can generate weak deformation, and the pressure can be transmitted to the micro-melting sensor. And the resistance of the four strain gauges sintered on the diaphragm is changed. According to the utility model, the micro-melting sensor is adopted, the silicon strain gauge is adopted by the sensor and is combined with the stainless steel diaphragm into a whole through high-temperature sintering, and the sensor is of an integral structure, has no welding seam, does not need a sealing element inside, has no leakage hidden danger, and is small and exquisite in appearance and low in cost; and secondly, a high-temperature sintering technology is adopted, the working temperature range is wider, and the product performance is more stable.

Description

Technical Field

[0001] The utility model relates to the technical field of transmitter devices, in particular to an SF6 gas density transmitter based on a micro-melting sensor. Background Art

[0002] SF6 high-voltage electrical equipment in substations, such as high-voltage circuit breakers, mutual inductors, fully enclosed switchgear GIS, and insulated switchgear, need to monitor their working status to ensure safety during operation. The existing transmitter is a silicon piezoresistive SF6 gas density transmitter, which is mainly used to monitor the density of SF6 gas in SF6 high-voltage equipment in various substations.

[0003] Existing silicon piezoresistive SF6 gas density transmitters use side sealing rings on the core or weld the core to the joint base. When the seals age or the welds are welded, there is a risk of leakage, which affects product quality. Secondly, the diaphragm base used in the core of the silicon piezoresistive sensor is made of stainless steel and is filled with silicone oil after welding. At ultra-low and high temperatures, the internal silicone oil properties change, affecting the stability of the product in high and low temperature environments. In addition, the sensor is large in size, the cost remains high, the supplier is single, and the supply cycle is long, which affects the delivery time. Utility Model Content

[0004] In view of the above defects or shortcomings, the purpose of the present invention is to provide an SF6 gas density transmitter based on a micro-melting sensor, which has a simple process and low cost, can not only ensure the quality reliability of the transmitter, but also simplify the product structure.

[0005] In order to achieve the above objectives, the technical solution of the utility model is:

[0006] An SF6 gas density transmitter based on a micro-melting sensor comprises: a pipe nozzle, a shell mounted on the pipe nozzle, and a connector mounted at the end of the shell; wherein a sensor is mounted in the shell, the sensor is connected to the pipe nozzle, and the sensor is connected to the connector via a circuit board.

[0007] A circuit board mounting seat is installed in the housing, and the circuit board is mounted on the circuit board mounting seat.

[0008] The circuit board is mounted on the circuit board mounting seat by screws.

[0009] The sensor is a micro-melting pressure sensor.

[0010] The sensor is integrated with a temperature measuring device.

[0011] The input end of the sensor is provided with a thread, and the input end of the sensor is connected to the inlet of the nozzle via the thread.

[0012] The upper end of the described connector can be connected to a display instrument.

[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0014] The present utility model provides an SF6 gas density transmitter based on a micro-melt sensor. Through the provided sensor, the pressure entering the lower end of the transmitter nozzle can act on the diaphragm inside the micro-melt sensor, causing a slight deformation of the diaphragm and resulting in changes in the resistance of the 4 strain gauges sintered on the diaphragm. When the bridge is powered by a voltage, a voltage output proportional to the pressure will be generated. After temperature compensation and signal amplification processing by the circuit board, it is then converted into a standard signal output of (4 - 20) mA, corresponding to the density of the SF6 gas inside the device. The present utility model uses a micro-melt sensor, which uses a silicon strain gauge and is integrated with a stainless steel diaphragm through high-temperature sintering. It is a monolithic structure without welds and does not require internal seals, eliminating leakage hazards. Moreover, it has a small size and low cost. Secondly, with the high-temperature sintering technology, the working temperature range is wider and the product performance is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the SF6 gas density transmitter of the present utility model based on a micro-melt sensor;

[0016] Figure 2 is the working principle of the SF6 gas density transmitter of the present utility model;

[0017] Figure 3 is the circuit diagram of the SF6 gas density transmitter of the present utility model.

[0018] Figure 1 In, 1 - nozzle; 2 - sensor; 3 - housing; 4 - circuit board mounting seat; 5 - screw; 6 - circuit board; 7 - connector. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present utility model will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0020] Such as Figure 1 、 2As shown, the utility model provides an SF6 gas density transmitter based on a micro-melting sensor, comprising: a take-over nozzle 1, a shell 3 is mounted on the take-over nozzle 1, and a connector 7 is mounted on the end of the shell 3; wherein, a sensor 2 is mounted in the shell 3, the sensor 2 is connected to the take-over nozzle 1, and the sensor 2 is connected to the connector 7 via a circuit board 6.

[0021] Preferably, a circuit board mounting seat 4 is installed in the housing 3 , and the circuit board 6 is mounted on the circuit board mounting seat 4 . The circuit board 6 is mounted on the circuit board mounting seat 4 by screws 5 .

[0022] It should be noted that the sensor 2 described in the present invention is a micro-melting pressure sensor, and a temperature measuring device is integrated into the sensor 2. The input end of the sensor 2 is provided with threads, which connect the input end of the sensor 2 to the inlet of the nozzle 1 via the threads. The sensor is connected to the amplification circuit board via the four-core wires on the micro-melting sensor. The lower end of the sensor is designed with threads, which connect it to the nozzle. The circuit board is fixed to the circuit board mounting base with screws and installed in the housing. The lower end of the housing is threadedly connected to the nozzle, and the upper end is connected to the Hirschmann connector. When pressure enters the pressure port at the lower end of the transmitter nozzle, it acts on the diaphragm in the micro-melting sensor, causing the diaphragm to slightly deform, causing the resistance of the four strain gauges sintered on the diaphragm to change. When the bridge is powered by voltage, a voltage output proportional to the pressure is generated. After temperature compensation and signal amplification by the circuit board, it is converted into a standard 4-20mA signal output corresponding to the density of the SF6 gas in the device.

[0023] Furthermore, the upper end of the connector 7 can be connected to a display instrument. When the SF6 gas density transmitter is connected to an XMT intelligent display instrument, it can also display and control SF6 gas density (output alarm and lockout switch signals). Communication with a computer system is achieved through the RS485 communication interface on the XMT, meeting the remote online monitoring requirements of operating equipment parameters in smart grids.

[0024] In the present invention, the function of the connector 7 is to transmit the (4-20) mA current signal to a standard digital multimeter through the wiring terminals on the connector 7 to display data, thereby playing the role of electrical connection and making signal transmission more convenient and faster.

[0025] Further, such as Figure 3 As shown, the circuit board 6 in the present invention includes a constant voltage source circuit, a transmission circuit and an anti-interference circuit.

[0026] Constant voltage source circuit: After preliminary filtering by inductor and capacitor, LM317 adjustable three-terminal voltage regulator performs primary voltage stabilization, and then precision voltage regulator diode performs secondary voltage stabilization to obtain a very stable 5V DC regulated power supply;

[0027] Transmitter circuit: Using chips imported from Germany, the sensor's millivolt signal is converted into a standard (4-20) mA current output through a signal processing circuit;

[0028] Anti-interference circuit: Since the SF6 gas density transmitter is used in a high-voltage substation with severe on-site electromagnetic interference, the circuit design adds lightning protection tubes, TVS tubes and other anti-interference devices to reduce the impact of electromagnetic interference on the circuit.

[0029] The functional principle of this utility model is:

[0030] like Figure 2 As shown in the figure, SF6 gas density monitoring is achieved by measuring the pressure of the SF6 gas inside the equipment at a reference temperature of 20°C. The transmitter's operating principle is that pressure acts on the stainless steel diaphragm inside the micro-melting sensor through the pressure interface at the lower end of the nozzle 1. After the diaphragm slightly deforms, the circuit board converts the SF6 gas pressure and temperature into electrical signals, which are then simultaneously fed into the chip. Temperature compensation software embedded in the chip performs calculations and converts these signals into a (4-20) mA standard current output corresponding to the SF6 gas pressure inside the equipment at a reference temperature of 20°C.

[0031] The advantages of the utility model are:

[0032] (1) Pressure measurement uses a micro-melting pressure sensor. The micro-melting sensor has an integral structure, no welds, and no leakage hazards, making the sealing performance of the transmitter measurement system stable and reliable.

[0033] (2) Temperature measurement uses a temperature measuring device integrated inside the pressure sensor, so that pressure and temperature signals can be obtained simultaneously from one device interface, making the transmitter compact and easy to install and use.

[0034] (3) The temperature compensation software design not only takes into account the pressure-temperature characteristics of SF6 gas, but also performs personalized compensation for the specific parameters of different sensors, so that the transmitter has higher temperature compensation accuracy.

[0035] (4) The transmitter circuit design includes anti-interference devices such as lightning protection tubes, TVS tubes, and varistors, which have strong anti-interference capabilities.

[0036] The working process of this utility model is:

[0037] Density measurement: When the pressure in the SF6 gas equipment enters the inner cavity of the nozzle 1 and acts on the diaphragm of the pressure-sensitive element at the lower end of the sensor 2, the diaphragm will produce a slight deformation, causing changes in the resistance of the 4 strain gauges sintered on the diaphragm. Power is supplied through the connector 7. When the bridge is powered by voltage, a voltage output proportional to the pressure will be generated. After temperature compensation and signal amplification by the circuit board 6, it is converted into a standard signal output of (4 - 20) mA, corresponding to the density of the SF6 gas in the equipment.

[0038] Display function: After the SF6 gas density transmitter is connected to the XMT type intelligent display instrument, it can also realize the display and control of the SF6 gas density. Communication with the computer system is achieved through the RS485 communication interface on the XMT to meet the requirements of remote online monitoring of the operating equipment parameters in the smart grid.

[0039] For those skilled in the art, it is obvious that the above specific factual examples are only the preferred solutions of the present invention. Therefore, the improvements and changes that those skilled in the art may make to some parts of the present invention still embody the principle of the present invention and achieve the purpose of the present invention, and all belong to the scope protected by the present invention.

Claims

1. An SF6 gas density transmitter based on a micro-melting sensor, characterized in that, include: A filler nozzle (1) is provided, wherein a housing (3) is mounted on the filler nozzle (1), and a connector (7) is mounted at the end of the housing (3); wherein a sensor (2) is mounted in the housing (3), the sensor (2) is connected to the filler nozzle (1), and the sensor (2) is connected to the connector (7) via a circuit board (6).

2. The SF6 gas density transmitter based on a micro-melting sensor according to claim 1, characterized in that, A circuit board mounting seat (4) is installed in the housing (3), and the circuit board (6) is installed on the circuit board mounting seat (4).

3. The SF6 gas density transmitter based on a micro-melting sensor according to claim 1, characterized in that, The circuit board (6) is mounted on the circuit board mounting seat (4) via screws (5).

4. The SF6 gas density transmitter based on a micro-melting sensor according to claim 1 or 2, characterized in that, The sensor (2) is a micro-melting pressure sensor.

5. The SF6 gas density transmitter based on a micro-melting sensor according to claim 4, characterized in that, The sensor (2) is integrated with a temperature measuring device.

6. The SF6 gas density transmitter based on a micro-melting sensor according to claim 4, characterized in that, The input end of the sensor (2) is provided with a thread, and the input end of the sensor (2) is connected to the inlet of the nozzle (1) via the thread.

7. The SF6 gas density transmitter based on a micro-melting sensor according to claim 1, characterized in that The upper end of the connector (7) can be connected to a display instrument.

8. The SF6 gas density transmitter based on a micro-melting sensor according to claim 1, characterized in that, The circuit board (6) comprises a constant voltage source circuit, a transmission circuit and an anti-interference circuit.

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