Safe heat preservation structure for hydrogen fluoride pipeline flange

Abstract

The utility model relates to a safe heat preservation structure for a hydrogen fluoride pipeline flange, which comprises two sections of pipelines containing anhydrous hydrogen fluoride, the pipeline flange used for being in butt joint with the two sections of pipelines and a sealing gasket located in a flange butt joint seam, a conductive wire is arranged on the periphery of the flange butt joint seam in the circumferential direction, and a heat preservation layer is wrapped outside the conductive wire. The thermal insulation layer is wrapped with a protective layer; a monitoring module is arranged outside the protective layer, and the two ends of the conductive wire penetrate through the heat preservation layer and the protective layer and extend out of the protective layer to be connected with the monitoring module. The monitoring module is in signal connection with the alarm module, and the monitoring module outputs a signal to the alarm module when the conductive wire is broken due to the corrosion effect of leaked hydrogen fluoride.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation of chemical pipelines, and in particular to a thermal insulation structure of a hydrogen fluoride pipeline flange. Background Art

[0002] Hydrogen fluoride is a colorless gas with a pungent odor at room temperature and pressure. It is a binary compound composed of fluorine and hydrogen. It liquefies below 19°C and has strong water absorption. Its unique chemical properties make it occupy an important position in many industrial fields, but at the same time, it is also a very dangerous substance. As a monobasic weak acid, hydrogen fluoride and its aqueous solution are toxic. Long-term contact or inhalation of hydrogen fluoride can have serious effects on human health. This compound can corrode bones and teeth, cause deformities, and seriously damage the physiological structure of the human body. What's more serious is that hydrofluoric acid can be absorbed by the human body through multiple pathways such as the skin, mucous membranes, respiratory tract and gastrointestinal tract, thereby causing poisoning reactions. Symptoms of poisoning may include skin burns, difficulty breathing, nausea and vomiting, and may even be life-threatening.

[0003] In industrial applications, such as the preparation of refrigerants and lithium battery electrolytes, HF is often used in an anhydrous state. As an important raw material, the safety of hydrogen fluoride transportation is of vital importance. Due to production needs, the temperature of anhydrous hydrogen fluoride needs to be maintained at a low temperature of -5°C to 0°C when it is transported in pipelines. In order to ensure the temperature of hydrogen fluoride during transportation, rubber and plastic insulation cotton is usually used for insulation. Rubber and plastic insulation cotton has been widely used in chemical production for its good insulation performance and stability. However, as the weak link in the pipeline system, the flange connection may cause hydrogen fluoride leakage due to material aging, loose connection and other reasons during long-term use. This leakage is difficult to detect by toxic gas detectors because the flange is wrapped with rubber and plastic insulation cotton. In this way, the leakage phenomenon is difficult to be discovered in time. Moreover, the leaked hydrogen fluoride is easily adsorbed by the rubber and plastic insulation cotton wrapped outside the flange, and then absorbs a certain amount of water to form an insulation material equivalent to being immersed in a hydrofluoric acid solution of a certain concentration. This contaminated rubber-plastic insulation cotton is difficult to identify in appearance, so it brings great hidden dangers to subsequent maintenance work. Maintenance personnel have no way to predict the leakage at the flange in advance, which greatly increases the risk of damage to maintenance personnel caused by the leakage at the flange. Once exposed to these rubber-plastic insulation cottons containing hydrogen fluoride, it is likely to cause skin burns, inhale harmful gases, and then show symptoms of poisoning, which may even threaten life in severe cases. Therefore, sufficient attention and effective measures must be given to the insulation work at the flange connection of hydrogen fluoride pipelines.

[0004] Patent CN203656468U discloses a chemical pipeline flange leak detection device wrapped with insulation material, in which a leak detection tube is arranged at the bottom of the flange connection, and the end of the leak detection tube exposes the insulation material layer. After the leak detection tube is inserted into the bottom of the flange connection at a vertical angle of 30-60°, the insulation material is installed, and the end of the leak detection tube is kept exposed to the insulation material layer. When the material leaks from the flange connection, the leaked material will flow out of the leak detection tube and be discovered. However, in reality, if the material leaks out slowly, the insulation material will quickly absorb the leaking material and it will not flow out of the leak detection tube. This technical solution cannot detect the leakage of the insulation flange in the first place. Summary of the invention

[0005] In order to solve the problem that hydrogen fluoride leakage at the flange connection of hydrogen fluoride pipeline is not easy to be discovered in time, and the leaked hydrogen fluoride is easily absorbed by the rubber-plastic insulation cotton wrapped outside the flange, thereby threatening the health and life of maintenance personnel, the inventor has designed a safe insulation structure for hydrogen fluoride pipeline flange, which ensures that once hydrogen fluoride leakage occurs at the hydrogen fluoride pipeline flange, it can be discovered in time.

[0006] The specific technical solutions are as follows:

[0007] A safe thermal insulation structure for hydrogen fluoride pipeline flanges, comprising two sections of pipelines containing anhydrous hydrogen fluoride, a pipeline flange for butting the two sections of pipelines, a sealing gasket located in a flange butt joint, and a conductive wire is arranged circumferentially outside the flange butt joint, the conductive wire is wrapped with a thermal insulation layer, and the thermal insulation layer is wrapped with a protective layer; a monitoring module is arranged outside the protective layer, two ends of the conductive wire pass through the thermal insulation layer and the protective layer, and extend outside the protective layer to be connected to the monitoring module; the monitoring module is connected to an alarm module signal, and when the conductive wire is broken due to the corrosion of leaked hydrogen fluoride, the monitoring module outputs a signal to the alarm module.

[0008] The safe thermal insulation structure for hydrogen fluoride pipeline flange is further designed in that the thermal insulation layer is a rubber-plastic thermal insulation cotton layer formed by circumferential wrapping.

[0009] The safe thermal insulation structure for hydrogen fluoride pipeline flange is further designed in that the protective layer is a stainless steel layer wrapped outside the thermal insulation layer.

[0010] The safe thermal insulation structure for hydrogen fluoride pipeline flange is further designed in that the conductive wire is a glass conductive fiber with cuprous sulfide as the conductive layer.

[0011] The safe thermal insulation structure for hydrogen fluoride pipeline flange is further designed in that the joint of the pipeline flange is wrapped with an insulating ring, and the inner wall of the insulating ring has a plurality of convex ridges arranged at intervals. When hydrogen fluoride leaks, it seeps out through the gaps between the convex ridges.

[0012] The safe thermal insulation structure for hydrogen fluoride pipeline flange is further designed in that the ring body of the insulating ring is provided with a through hole.

[0013] The safe thermal insulation structure for hydrogen fluoride pipeline flange is further designed in that the conductive wire is a metal wire that is easily corroded by hydrogen fluoride.

[0014] The beneficial effects of the utility model are:

[0015] When hydrogen fluoride leaks out, it will quickly react with the conductive wire, and the resistance value will increase instantly. When the monitoring module detects that the resistance exceeds the normal range, it will trigger the alarm module to prompt the staff to repair the flange leakage in time. When glass conductive fiber is used, glass reacts with hydrogen fluoride more quickly, directly causing the conductive wire to break. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0017] Figure 2 It is a schematic diagram of the insulating ring installation structure. DETAILED DESCRIPTION

[0018] The present invention is further described below with reference to the accompanying drawings and embodiments:

[0019] A safe thermal insulation structure for hydrogen fluoride pipeline flanges, comprising two sections of pipelines 1 containing anhydrous hydrogen fluoride, a pipeline flange 2 for butting the two sections of pipelines, a sealing gasket located in a flange butt joint, and a conductive wire 3 is circumferentially arranged outside the flange butt joint, and a thermal insulation layer 4 is wrapped outside the conductive wire, wherein the thermal insulation layer is a rubber-plastic thermal insulation cotton layer formed by circumferential wrapping.

[0020] The insulation layer is wrapped with a protective layer 5, which is a stainless steel layer wrapped outside the insulation layer. A monitoring module 6 is arranged outside the protective layer, and the two ends of the conductive wire pass through the insulation layer and the protective layer, and extend outside the protective layer to connect with the monitoring module, wherein the conductive wire should be insulated at the contact point when passing through the protective layer; the monitoring module is connected to the alarm module 7 by signal, and when the conductive wire is broken due to the corrosion of leaked hydrogen fluoride, the monitoring module outputs a signal to the alarm module.

[0021] The conductive wire can be a metal wire that is easily corroded by hydrogen fluoride, such as conventional metals such as iron and aluminum; a glass conductive fiber with cuprous sulfide as a conductive layer can also be selected. When glass conductive fiber is used, the strong corrosion effect of hydrogen fluoride on silicon dioxide can also ensure that the conductive wire is quickly disconnected when encountering hydrogen fluoride.

[0022] In order to ensure that when hydrogen fluoride leaks, the conductive wire directly contacts hydrogen fluoride and reacts quickly, and no insulation protection treatment is performed on the surface of the conductive wire, the conductive wire is usually directly wrapped around the sealing gasket of the flange joint to prevent the conductive wire from contacting the flange. In order to further ensure this isolation effect, the joint of the pipeline flange is wrapped with an insulating ring 8 made of plastic material, and the inner wall of the insulating ring has a number of convex ridges 81 arranged at intervals. When hydrogen fluoride leaks, it seeps out through the gaps between the convex ridges. In addition, a through hole 82 is provided in the ring body of the insulating ring. The conductive wire is wrapped around the outer ring of the insulating ring 8.

[0023] The device for alarming due to a sudden change in the resistance value of the monitored object belongs to the common prior art. The main technical means adopted in this embodiment are as follows:

[0024] Power module: Provides stable DC power, including AC-DC power adapter: such as MEAN WELL GST-45A12, outputs 12V DC. And, power cord: standard power plug cord, connecting the power adapter to the DC socket inside the device.

[0025] Monitoring module: contains a conductive wire to be monitored and a current / voltage detection circuit to detect whether the conductive wire is broken. Specifically, the current / voltage detection circuit can use a resistor connected in series at both ends of the conductive wire and a voltage comparator (such as LM393) to detect whether the voltage at both ends of the conductive wire is below a threshold, thereby determining whether the conductive wire is broken. Connection method: The conductive wire is connected in series with a small resistance resistor and then connected to a voltage comparator, and the output of the comparator is connected to the digital input pin of the microcontroller.

[0026] Signal processing module: receives the signal from the monitoring module, determines the state of the conductive wire, and controls the alarm output. Specifically, it is a microcontroller: such as Arduino Uno R3, which is responsible for receiving the signal from the monitoring circuit, executing the judgment logic, and controlling the alarm output. Connection method: The digital input pin of the microcontroller is connected to the output of the voltage comparator, and the digital output pin is connected to the alarm module.

[0027] Alarm module: including sound and light alarm and / or wireless signal transmitter. Specifically including sound and light alarm: such as buzzer and LED light. And GSM / GPRS module (optional): such as SIM800L, used to send SMS alarm. Connection method: The positive poles of buzzer and LED light are connected to the digital output pins of microcontroller, and the negative poles are connected to the ground wire. GSM / GPRS module is connected to microcontroller through UART interface.

[0028] The power module provides a stable DC power supply for the entire system. When the conductive wire is normal, the voltage at both ends of it remains within a normal range, and the voltage comparator outputs a low-level signal to the microcontroller. When the conductive wire is broken due to corrosion, the voltage at both ends of it drops rapidly, and the voltage comparator outputs a high-level signal to the microcontroller. After receiving the high-level signal, the microcontroller determines that the conductive wire is broken and controls the sound and light alarm to send an alarm signal. If the GSM / GPRS module is selected, a text message alarm will be sent to the preset mobile phone number at the same time.

Claims

1. A safe thermal insulation structure for hydrogen fluoride pipeline flange, characterized in that: The invention comprises two sections of pipelines containing anhydrous hydrogen fluoride, a pipeline flange for butting the two sections of pipelines, a sealing gasket located in the flange butt joint, and a conductive wire is arranged circumferentially outside the flange butt joint, the conductive wire is wrapped with a thermal insulation layer, and the thermal insulation layer is wrapped with a protective layer; a monitoring module is arranged outside the protective layer, two ends of the conductive wire pass through the thermal insulation layer and the protective layer, and extend outside the protective layer to be connected with the monitoring module; the monitoring module is connected with an alarm module signal, and when the conductive wire is broken due to the corrosion of leaked hydrogen fluoride, the monitoring module outputs a signal to the alarm module.

2. A safe thermal insulation structure for hydrogen fluoride pipeline flange according to claim 1, characterized in that: The heat-insulating layer is a rubber-plastic heat-insulating cotton layer formed by circumferential wrapping.

3. A safe thermal insulation structure for hydrogen fluoride pipeline flange according to claim 1, characterized in that: The protective layer is a stainless steel layer wrapped outside the heat-insulating layer.

4. A safe thermal insulation structure for hydrogen fluoride pipeline flange according to claim 1, characterized in that: The conductive filament is a glass conductive fiber with cuprous sulfide as the conductive layer.

5. A safe thermal insulation structure for hydrogen fluoride pipeline flange according to claim 1, characterized in that: The butt joint of the pipeline flange is wrapped with an insulating ring, and the inner wall of the insulating ring has a plurality of convex ridges arranged at intervals. When hydrogen fluoride leaks, it seeps out through the gaps between the convex ridges.

6. A safe thermal insulation structure for hydrogen fluoride pipeline flange according to claim 5, characterized in that: The ring body of the insulating ring is provided with a through hole.

7. A safe thermal insulation structure for hydrogen fluoride pipeline flange according to claim 5, characterized in that: The conductive wire is a metal wire that is easily corroded by hydrogen fluoride.

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