High-pressure back flushing device and back flushing method for instrument sampling pipe

Abstract

The invention discloses a high-pressure blowback device and a blowback method for an instrument sampling pipe, and relates to the technical field of pressure monitoring instruments, the high-pressure blowback device comprises a blowback pipeline, a multi-way electromagnetic valve and a controller; a communicating port, a back flushing port and a pressure tapping port are formed in the multi-way electromagnetic valve, the communicating port is used for being communicated with the sampling pipe, the back flushing port is communicated with the air outlet end of the back flushing pipeline, and the pressure tapping port is used for being communicated with a pressure monitoring instrument; the air inlet end of the blowback pipeline is used for introducing a blowback medium; and the controller is electrically connected with the multi-way electromagnetic valve and is used for switching the communication port to be communicated with the back flushing port and the pressure tapping port respectively, so that long-term stable operation of the pressure monitoring instrument is ensured, and the manual operation frequency can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure monitoring instruments, in particular to a high-pressure back flushing device and method for instrument sampling pipes. BACKGROUND

[0002] Instrument pressure transmitters include positive pressure transmitters, negative pressure transmitters and differential pressure transmitters. Due to construction or other reasons, the length of some monitoring instrument sampling pipes may reach about 15 meters, and the monitored pressure medium may be gas, dust or mixed gas. Long-term sampling may cause dust deposition to block the sampling pipe, and long-term sampling of gas and ammonia mixed medium may cause crystallization to block the sampling pipe. In order to solve the blocking problem of the monitoring instrument sampling pipe, the traditional method is mainly manual cleaning and maintenance. However, manual cleaning not only has a large workload, but also has high labor intensity, and cannot timely find and handle the blocking problem of the sampling pipe. During the cleaning process, the instrument needs to be taken out of the device monitoring system for a long time, which affects the safe production and operation of the power plant. SUMMARY

[0003] The purpose of the present application is to provide a high-pressure back flushing device and method for instrument sampling pipes to solve the problems existing in the prior art, to ensure the long-term stable operation of the pressure monitoring instrument, and to reduce the number of manual operations.

[0004] To achieve the above-mentioned purpose, the present application provides the following scheme: the present application provides a high-pressure back flushing device for instrument sampling pipes, comprising a back flushing pipeline, a multi-way electromagnetic valve and a controller;

[0005] A communication port, a back flushing port and a pressure taking port are formed on the multi-way electromagnetic valve, the communication port is used to communicate with the sampling pipe, the back flushing port communicates with the gas outlet end of the back flushing pipeline, and the pressure taking port is used to communicate with the pressure monitoring instrument;

[0006] The gas inlet end of the back flushing pipeline is used to introduce back flushing medium;

[0007] The controller is electrically connected with the multi-way electromagnetic valve, and is used to switch the communication port to communicate with the back flushing port and the pressure taking port, respectively.

[0008] Optionally, a pressure reducing valve is arranged on the back flushing pipeline.

[0009] Optionally, a first stop valve is arranged on the back flushing pipeline, and the first stop valve is located on the gas inlet side of the pressure reducing valve.

[0010] Optionally, the pressure monitoring instrument is a pressure transmitter, and a transmitter connector of the pressure transmitter communicates with the pressure taking port.

[0011] Optionally, the transmitter connector and the pressure taking port are in threaded communication.

[0012] Optionally, the pressure monitoring instrument is a differential pressure transmitter, and the differential pressure transmitter is matched with two multi-way electromagnetic valves and two sampling pipes;

[0013] The three-valve group matched with the differential pressure transmitter is connected to the pressure tapping ports of the two multi-way electromagnetic valves through high-pressure connectors and low-pressure connectors, respectively.

[0014] The outlet ends of the backflushing pipelines are connected to the backflushing ports of the two multi-way electromagnetic valves through backflushing branch pipes, respectively.

[0015] The two sampling pipes are connected to the communication ports of the two multi-way electromagnetic valves.

[0016] Optionally, the high-pressure connector and the low-pressure connector are threadedly connected to the two pressure tapping ports, respectively.

[0017] Optionally, the sampling pipe is provided with two second stop valves, which are arranged in sequence along the flow direction of the medium in the sampling pipe.

[0018] Optionally, the controller is electrically connected to the pressure monitoring instrument.

[0019] The application further provides a backflushing method, which comprises the following steps:

[0020] Before backflushing operation: the multi-way electromagnetic valve is in the first working position, the communication port and the pressure tapping port of the multi-way electromagnetic valve are in communication, and the communication port and the backflushing port of the multi-way electromagnetic valve are disconnected, so that the pressure monitoring instrument monitors the real-time pressure of the sampling pipe through the pressure tapping port.

[0021] During backflushing operation: the multi-way electromagnetic valve is in the second working position, the communication port and the pressure tapping port of the multi-way electromagnetic valve are disconnected, and the communication port and the backflushing port of the multi-way electromagnetic valve are connected, so that the backflushing pipeline and the sampling pipe are connected, and the sampling pipe is backflushed.

[0022] The application has the following technical effects compared with the prior art:

[0023] The high-pressure backflushing device for the sampling pipe of the pressure monitoring instrument disclosed by the application is used to solve the problem that the sampling pipe matched with the pressure monitoring instrument is easily blocked when the pressure needs to be monitored and the medium is sampled, and the monitoring value is distorted, thereby affecting the production process. The controller is electrically connected to the multi-way electromagnetic valve, and is used to switch the communication port to be connected to the backflushing port and the pressure tapping port, respectively, so that the backflushing pipeline and the sampling pipe are connected through the multi-way electromagnetic valve during backflushing operation, and manual cleaning and maintenance can be replaced, especially for the pressure monitoring instrument in a high-risk environment, the number of manual operations is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0025] Figure 1 In an example disclosed by the present application, the gas circuit schematic diagram in the high-pressure backflush undisturbed control principle of the sampling pipe of the pressure transmitter;

[0026] Figure 2 In an example disclosed by the present application, the control logic diagram in the high-pressure backflush undisturbed control principle of the sampling pipe of the pressure transmitter;

[0027] Figure 3 In an example disclosed by the present application, the gas circuit schematic diagram in the high-pressure backflush undisturbed control principle of the sampling pipe of the differential pressure transmitter;

[0028] Figure 4 In an example disclosed by the present application, the control logic diagram in the high-pressure backflush undisturbed control principle of the sampling pipe of the differential pressure transmitter;

[0029] In the high-pressure backflush device for the sampling pipe of the instrument, 1 is a backflush pressure source, 2 is an instrument backflush pressure main pipe, 3 is a first stop valve, 4 is a pressure reducing valve, 5 is a pressure transmitter, 6 is a pressure diaphragm capsule, 7 is a multi-way electromagnetic valve, 8 is a second stop valve, 9 is a process main pipe, 10 is a high-pressure side diaphragm capsule, 11 is a low-pressure side diaphragm capsule, 12 is a differential pressure transmitter, 13 is a three-valve group, and 14 is a sampling pipe. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, and all other embodiments obtained by those of ordinary skill in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0031] The present application aims to provide a high-pressure backflush device and method for the sampling pipe of an instrument, so as to solve the problems in the prior art, ensure the long-term stable operation of the pressure monitoring instrument, and reduce the number of manual operations.

[0032] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0033] As Figures 1 to 4As shown, the application provides a high-pressure back flushing device for instrument sampling pipe, which is applied to pressure monitoring instrument, and the pressure monitoring instrument includes but is not limited to coal mill outlet air pressure positive pressure pressure transmitter, coal mill outlet air and powder mixture positive pressure differential pressure transmitter, economizer outlet flue gas pressure negative pressure differential pressure transmitter, furnace negative pressure differential pressure transmitter, steam turbine circulating water inlet pressure positive pressure pressure transmitter, steam turbine circulating water outlet pressure positive pressure pressure transmitter, desulfurization island outlet flue gas pressure negative pressure differential pressure transmitter, desulfurization island inlet flue gas pressure negative pressure differential pressure transmitter, denitration outlet flue gas pressure negative pressure differential pressure transmitter, denitration inlet flue gas pressure negative pressure differential pressure transmitter, denitration SCR reaction zone pressure positive pressure pressure gauge and the like. And the sampling medium corresponding to the pressure monitoring instrument includes but is not limited to gas, gas-liquid mixture, gas-dust mixture, liquid and liquid-particle mixture and the like. Wherein, the pressure monitoring instrument is matched with a sampling pipe 14, and the joint of the pressure monitoring instrument is communicated to the process mother pipe 9 through the sampling pipe 14.

[0034] The high-pressure back flushing device for instrument sampling pipe disclosed by the application includes a back flushing pipeline, a multi-way electromagnetic valve 7 and a controller. The multi-way electromagnetic valve 7 is provided with a communication port, a back flushing port and a pressure taking port. The communication port is used for communicating with the sampling pipe 14. Specifically, the two ends of the sampling pipe 14 are respectively communicated with the communication port and the process mother pipe 9. The back flushing port is communicated with the gas outlet end of the back flushing pipeline. The pressure taking port is used for communicating with the pressure monitoring instrument. The gas inlet end of the back flushing pipeline is used for introducing back flushing medium. Preferably, the gas inlet end of the back flushing pipeline is communicated with an instrument back flushing pressure mother pipe 2. The instrument back flushing pressure mother pipe 2 is communicated with a back flushing pressure source 1. The same instrument back flushing pressure mother pipe 2 can be applied to multiple high-pressure back flushing devices for instrument sampling pipe.

[0035] And preferably, the blowback medium provided by the blowback pressure source 1 is matched with the medium in the process main pipe 9. For example, in a direct-fired coal pulverizing system of a thermal power plant: the blowback medium provided by the blowback pressure source 1 is dry and oil-free high-pressure compressed air from an air compressor, a filter system, and an air drying system. The medium in the process main pipe 9 is a mixture of coal powder and primary air (referred to as a primary air-powder flow), which is directly blown to a boiler burner through a coal powder pipeline and is injected into a furnace for combustion by the burner. The process control system needs to monitor the positive pressure value of the process main pipe 9 in real time through the sampling pipe 14 to adjust the boiler control system. Because the coal powder mixture is prone to block the sampling pipe, clean high-pressure compressed air needs to be used for blowback to unblock. For another example, in the core part of the nitrogen oxide emission of the SCR reaction zone of a denitration system of a thermal power plant: the blowback medium provided by the blowback pressure source 1 is dry and oil-free high-pressure compressed air from an air compressor, a filter system, and an air drying system, or high-pressure nitrogen gas used in an explosion-proof and high-humidity environment. The medium in the process main pipe 9 is reducing agent ammonia gas. The boiler tail flue gas enters the SCR reactor after passing through an economizer. In the flue gas inlet of the reactor, the ammonia gas is uniformly injected into the flue gas through an ammonia injection grid. The mixed gas flows through the catalyst layer and reacts at 300-400°C. After the reaction, the flue gas enters an air preheater and a subsequent dust removal and desulfurization system. In the SCR system, the sampling pipe 14 is prone to be blocked by dust or ammonium salt. This leads to the process control system being unable to accurately monitor the ammonia injection amount and uniformity, which may cause excessive ammonia injection and further cause ABS generation and air preheater blockage. The blocked sampling pipe 14 is like a “blind controller”, which, if left unchecked, will cause a catastrophic chain failure. Real-time monitoring combined with active protection is the only way to avoid ABS vicious cycle.

[0036] In the embodiment, the controller is electrically connected with the multi-way electromagnetic valve 7 for switching the communication port to be connected with the blowback port and the pressure taking port, respectively. The controller preferably adopts a distributed control system (Distributed Control System).

[0037] In the embodiment, the multi-way electromagnetic valve 7 is a two-position three-way electromagnetic valve, the valve core of which can be switched between two working positions. When the valve core is in the first working position, the communication port and the pressure taking port are in a communication state, and the communication port and the blowback port are in a disconnected state. When the valve core is in the second working position, the communication port and the pressure taking port are disconnected, and the communication port and the blowback port are connected.

[0038] In the embodiment, the pressure collection of the application is completed by the pressure monitoring instrument, logical judgment is made by the controller according to the parameters set by the operator, the controller outputs the judgment result to the multi-way electromagnetic valve 7, and drives the multi-way electromagnetic valve 7 to act, to perform the back flushing operation, and outputs the real-time value of the collected pressure and the alarm information according to the logical judgment, and the whole pressure collection, logical judgment, and operation execution (including alarm output) are a closed-loop operation process, which only needs to be adjusted according to the process and the site condition.

[0039] The high-pressure back flushing device for the sampling pipe of the instrument disclosed in the application is used to solve the problem that the sampling pipe 14 matched with the pressure monitoring instrument is easy to be blocked when the medium needs to be sampled and monitored, and the monitoring value is distorted, thereby affecting the production process. The controller is electrically connected with the multi-way electromagnetic valve 7, which is used to switch the communication ports to be communicated with the back flushing port and the pressure taking port respectively, so that the back flushing pipeline and the sampling pipe 14 are communicated through the multi-way electromagnetic valve 7 during the back flushing operation, thereby being able to replace the manual cleaning and maintenance, especially for the pressure monitoring instrument in a high-risk environment, and greatly reducing the number of manual operations.

[0040] Further, first of all, it needs to be pointed out that if the back flushing pipeline is connected to the sampling pipe 14 through a stop valve, the stop valve is in a closed state when the medium pressure in the process mother pipe 9 is monitored, and the stop valve needs to be opened to back flush the blocked sampling pipe 14 when the sampling pipe 14 needs to be back flushed, but the pressure monitoring instrument will bear the same back flushing pressure during the back flushing process, but when the pressure monitoring instrument adopts a differential pressure transmitter 12 and a micro-pressure pressure gauge, etc., the high back flushing pressure will cause the deformation or even damage of the low-pressure gauge diaphragm of the differential pressure transmitter 12 and the micro-pressure pressure gauge; in the application, the pressure monitoring instrument can be isolated first through the action of the multi-way electromagnetic valve 7 when the sampling pipe 14 is back flushed at high pressure, and then the sampling pipe 14 is back flushed through the back flushing pipeline, so as to protect the pressure monitoring instrument from the influence of the back flushing pressure, and the pressure monitoring instrument remains unchanged after isolation. The parameters before isolation are unchanged, so as to achieve the purpose of non-disturbance back flushing of the sampling pipe 14 by the pressure monitoring instrument.

[0041] Further, under the condition that the diameter of the sampling pipe 14, the sampling medium, and the production process remain unchanged, the back flushing pressure, time, and back flushing effect are theoretically proportional, provided that the pressure resistance of the pressure diaphragm is considered, and the high pressure generated during the back flushing operation cannot damage the pressure diaphragm. When the back flushing operation is performed, the multi-way electromagnetic valve 7 is set first to cut off the communication between the pressure monitoring instrument and the sampling pipe 14, and then the back flushing pipeline and the sampling pipe 14 are connected, to back flush the sampling pipe 14, so as to reduce the back flushing time while ensuring the back flushing effect, only by increasing the back flushing pressure, so as to realize the back flushing of the sampling pipe 14 at high pressure, to reduce the back flushing time under the premise of improving the back flushing effect.

[0042] In a specific embodiment, a pressure reducing valve 4 is arranged on the back flushing pipeline. The pressure reducing valve 4 is arranged to adjust the back flushing pressure in the back flushing pipeline and achieve the required back flushing pressure. Before the back flushing operation, the pressure of the pressure reducing valve 4 is set according to the sampling medium and the required condition on site, so as to meet the requirements of short back flushing time and improved back flushing effect. Further, the pressure in the back flushing pipeline can be adjusted by adjusting the pressure reducing valve 4, so as to reduce the influence on the working condition of the process mother pipeline 9.

[0043] In a specific embodiment, a first stop valve 3 is arranged on the back flushing pipeline. The first stop valve 3 is arranged on the gas inlet side of the pressure reducing valve 4. The first stop valve 3 is arranged to realize the on-off function of the back flushing pipeline.

[0044] In a specific embodiment, the high pressure back flushing device for the sampling pipeline of the pressure monitoring instrument mainly includes a pressure transmitter 5 and a differential pressure transmitter 12. In order to prevent the sampling pipeline 14 of the pressure transmitter 5 and the differential pressure transmitter 12 from being blocked, the pressure receiving element of the differential pressure transmitter 12 mainly includes two parts, i.e. a high pressure side diaphragm capsule 10 and a low pressure side diaphragm capsule 11. The pressure receiving element of the pressure transmitter 5 only includes one pressure diaphragm capsule 6. During the back flushing operation, the pipeline between the back flushing pressure and the diaphragm capsule is cut off, and the back flushing pressure is increased, so as to ensure the back flushing effect and reduce the back flushing time. The system control logic of the differential pressure transmitter 12 and the pressure transmitter 5 during the back flushing operation is basically the same.

[0045] It should be noted that if the back flushing pipeline is arranged at a suitable position of the sampling pipeline 14 close to the pressure monitoring instrument, and the back flushing medium is provided by the back flushing pressure source 1 to flush the sampling pipeline 14, the problem of the blocked sampling pipeline 14 can be solved. However, the range of the pressure transmitter 5 used for different process pressures is also different. In particular, the differential pressure transmitter 12 has a special structure, and the pressure difference between the high pressure side and the low pressure side cannot be too large, otherwise the differential pressure transmitter 12 will be damaged. Therefore, the maximum pressure of the instantaneous back flushing of the pressure transmitter 5 must be less than the upper limit pressure of the range of the pressure transmitter 5. The high pressure side and the low pressure side of the differential pressure transmitter 12 need to be back flushed at the same time, and the back flushing pressure of the two sides must not exceed the maximum static pressure of the diaphragm capsule. The pressure difference between the high pressure side and the low pressure side cannot be too large. If a pressure regulating valve is arranged on each back flushing pipeline to limit the back flushing pressure and protect the pressure monitoring instrument, the higher the back flushing pressure, the higher the flushing efficiency and quality. However, since the pressure monitoring instrument also bears the back flushing pressure, the back flushing pressure of the sampling pipeline 14 with large dust and easy crystallization cannot reach the high efficiency and high quality flushing result due to the limited range of the pressure monitoring instrument.

[0046] In the embodiment, preferably, the pressure monitoring instrument is a pressure transmitter 5, a transmitter joint of the pressure transmitter 5 is communicated with the pressure tapping, before the back flushing operation, the pressure of the pressure reducing valve 4 is set according to the sampling medium and the required condition of the site. And before the back flushing operation, the communication port of the multi-way electromagnetic valve 7 and the pressure tapping are in communication, the communication port of the multi-way electromagnetic valve 7 and the back flushing port are in disconnection, at this time, the pressure transmitter 5 monitors the real-time pressure of the sampling pipe 14 through the pressure tapping. During the back flushing operation, the electromagnetic valve coil of the multi-way electromagnetic valve 7 is electrified, the spool of the multi-way electromagnetic valve 7 is actuated, the communication port of the multi-way electromagnetic valve 7 and the pressure tapping are disconnected, the communication port of the multi-way electromagnetic valve 7 and the back flushing port are communicated, and then the back flushing pipeline and the sampling pipe 14 are connected, and the sampling pipe 14 is back flushed until the high pressure back flushing operation of the sampling pipe 14 is completed. At this time, the monitoring value of the pressure transmitter 5 is the value before the multi-way electromagnetic valve 7 is actuated, and the high and low of the back flushing pressure cannot affect the pressure diaphragm chamber 6 of the pressure transmitter 5, so the size of the back flushing pressure is no longer limited by the upper limit of the range of the pressure transmitter 5, only the back flushing effect and quality need to be considered to adjust the back flushing pressure.

[0047] The transmitter joint is communicated with the pressure tapping in a threaded manner, so that the pressure transmitter 5 can be directly connected with the multi-way electromagnetic valve 7, avoiding the use of other pipelines to connect the transmitter joint and the pressure tapping, and reducing the possibility of further clogging.

[0048] In the embodiment, as another preferred, the pressure monitoring instrument is a differential pressure transmitter 12, the differential pressure transmitter 12 is equipped with two multi-way electromagnetic valves 7 and two sampling tubes 14; the differential pressure transmitter 12 is equipped with a three-valve group 13, the high-pressure joint and the low-pressure joint of the three-valve group 13 are respectively communicated to the pressure tapping ports of the two multi-way electromagnetic valves 7, it should be noted that the three-valve group 13 is combined with the means of the differential pressure transmitter 12 itself, which belongs to the prior art, so for the communication of the multi-way electromagnetic valve 7 and the differential pressure transmitter 12, it is communicated on the three-valve group 13 through the multi-way electromagnetic valve 7, specifically, the differential pressure transmitter 12 high-pressure side diaphragm box 10 communicates the high-pressure joint of the three-valve group 13, the differential pressure transmitter 12 low-pressure side diaphragm box 11 communicates the low-pressure joint of the three-valve group 13; the air outlet ends of the back flushing pipeline are respectively communicated with the back flushing ports of the two multi-way electromagnetic valves 7; the two sampling tubes 14 are both communicated to the communication ports of the two multi-way electromagnetic valves 7. Before the back flushing operation, the pressure of the pressure reducing valve 4 is set according to the sampling medium and the required situation on site. And before the back flushing operation, the communication ports and the pressure tapping ports of the two multi-way electromagnetic valves 7 are in a communication state, the communication ports and the back flushing ports of the two multi-way electromagnetic valves 7 are in a disconnected state, at this time, the high-pressure side and the low-pressure side of the differential pressure transmitter 12 respectively monitor the real-time pressure of the two sampling tubes 14 through the two pressure tapping ports respectively and display the differential pressure value. When back flushing, the electromagnetic valve coils of the two multi-way electromagnetic valves 7 are powered at the same time, the spools of the two multi-way electromagnetic valves 7 act synchronously, the communication ports and the pressure tapping ports of the two multi-way electromagnetic valves 7 are disconnected, the communication ports and the back flushing ports of the two multi-way electromagnetic valves 7 are connected, thereby connecting the back flushing pipeline and the two sampling tubes 14, and synchronously back flushing the two sampling tubes 14 until the high-pressure back flushing operation of the two sampling tubes 14 is completed. At this time, the monitoring value of the differential pressure transmitter 12 is the differential pressure value before the action of the two multi-way electromagnetic valves 7, the high and low of the back flushing pressure cannot affect the differential pressure transmitter 12 high-pressure side diaphragm box 10 and the low-pressure side diaphragm box 11, so the size of the back flushing pressure is no longer limited by the maximum range of the differential pressure transmitter 12, and is no longer limited by the damage of the differential pressure transmitter 12 caused by the excessive differential pressure, only the back flushing effect and quality need to be considered to adjust the back flushing pressure of the differential pressure transmitter 12. Especially for the differential pressure transmitter 12 with a small differential pressure range, the risk of damaging the differential pressure transmitter 12 caused by the excessive differential pressure between the high-pressure side diaphragm box 10 and the low-pressure side diaphragm box 11 during back flushing is eliminated.

[0049] Among them, the high-pressure joint and the low-pressure joint are respectively communicated with the two pressure tapping ports by threads, so that the three-valve group 13 equipped with the differential pressure transmitter 12 can be directly connected with the two multi-way electromagnetic valves 7, avoiding connecting the three-valve group 13 and the pressure tapping port by other pipelines, reducing the possibility of further blockage.

[0050] In a specific embodiment, two second stop valves 8 are arranged on the sampling pipe 14, and the two second stop valves 8 are arranged in sequence along the flow direction of the medium in the sampling pipe 14. The two second stop valves 8 are arranged to realize the on-off function of the sampling pipe 14. When one of the second stop valves 8 fails, the other second stop valve 8 can still complete the cutting work.

[0051] In a specific embodiment, the controller is electrically connected with the pressure monitoring instrument. During the operation, on the one hand, if the multi-way electromagnetic valve 7 fails and the back flushing pressure leaks to the pressure diaphragm chamber of the pressure monitoring instrument, causing the pressure to exceed the set safety pressure of the pressure diaphragm chamber, the controller can monitor the pressure change of the pressure monitoring instrument. When the pressure exceeds the set safety pressure, the controller will immediately control to stop the back flushing operation. Specifically, the controller can control the pressure regulating valve 4 to adjust the pressure, or in the mode that the first stop valve 3 is arranged on the back flushing pipeline, the first stop valve 3 is preferably an electromagnetic valve, which is electrically connected with the controller, and then the controller drives the first stop valve 3 to act, so as to cut off the back flushing pipeline. On the other hand, if the back flushing pressure leaks to the pressure diaphragm chamber of the pressure monitoring instrument due to other reasons, the controller can control the multi-way electromagnetic valve 7 to act, so as to disconnect the communication state between the back flushing pipeline and the sampling pipe 14, and restore the communication state between the pressure monitoring instrument and the sampling pipe 14.

[0052] In the embodiment, the controller is electrically connected with the alarm mechanism. When the controller obtains the signal that the data of the pressure monitoring instrument is abnormal, the controller outputs the signal to the alarm mechanism to drive the alarm mechanism to alarm, so as to remind the operator. Then, the operator resets the alarm mechanism after dealing with the related fault, and then the back flushing operation can be continued.

[0053] In the embodiment, before the normal back flushing operation, the pressure upper limit alarm and the pressure lower limit alarm are set in the controller according to the safety pressure range of the pressure diaphragm chamber of the pressure monitoring instrument. When the controller detects that the real-time collected pressure of the pressure monitoring instrument exceeds the set safety pressure range, the controller will immediately control to stop the back flushing operation.

[0054] The whole device is also provided with a monitoring system. Since the controller is electrically connected with the multi-way electromagnetic valve 7, the controller sets that the number of back flushing operations in a period cannot exceed a set number. Otherwise, the controller will immediately cut off the automatic back flushing mode, for example, by controlling the multi-way electromagnetic valve 7 to disconnect the communication between the back flushing pipeline and the sampling pipe 14, and the controller will alarm to remind the operator. At this time, the operator needs to check the situation on site to prevent high-frequency back flushing operation caused by pipeline damage and leakage. Under normal circumstances, during the back flushing operation, the monitoring system monitors that the value of the pressure monitoring instrument is the value of a scanning period before the back flushing operation, and the influence of the back flushing operation on the monitoring system can be basically ignored, so as to avoid affecting the safe production and operation of the power plant.

[0055] Furthermore, during the entire closed-loop operation of the present invention, when performing a backflushing operation, the pipeline between the pressure membrane box and the sampling tube 14 is first cut off under the sampling pressure state. At this time, the pressure displayed by the monitoring system is the sampling pressure of the sampling tube 14 before the backflushing operation. Moreover, because the membrane box is isolated, the backflushing pressure is theoretically not limited by the maximum pressure of the membrane box. While ensuring the backflushing effect and increasing the backflushing pressure, the backflushing time can be greatly shortened, and the impact time of the backflushing operation on the monitoring system can be reduced.

[0056] In specific use, the type of pressure monitoring instrument is selected according to the site: (1) When the monitoring instrument is a pressure transmitter 5, according to Figure 1 The gas circuit principle diagram of the pressure transmitter sampling tube high pressure backflush disturbance-free control principle shown in the figure, Figure 1 The control logic diagram of the pressure transmitter sampling tube high pressure backflush disturbance-free control principle shown in the figure is used to select a suitable pressure transmitter 5 in combination with the on-site process, set the control logic parameters, and implement them. (2) When the monitoring instrument is a differential pressure transmitter 12, according to Figure 1 The gas circuit principle diagram of the differential pressure transmitter sampling tube high pressure backflush disturbance-free control principle shown in the figure, Figure 1 The control logic diagram of the differential pressure transmitter sampling tube high-pressure backflushing disturbance-free control principle shown is used to select a suitable differential pressure transmitter 12 in combination with the on-site process, set the various control logic parameters, and implement them.

[0057] A backflushing method is also provided, comprising the following steps:

[0058] Before backflush operation: the multi-way solenoid valve 7 is in the first working position, the communication port and the pressure port of the multi-way solenoid valve 7 are in a connected state, the communication port and the backflush port of the multi-way solenoid valve 7 are in a disconnected state, and the pressure monitoring instrument monitors the real-time pressure of the sampling tube 14 through the pressure port;

[0059] During backflushing operation: the multi-way solenoid valve 7 is in the second working position, the connecting port of the multi-way solenoid valve 7 and the pressure port are disconnected, the connecting port of the multi-way solenoid valve 7 and the backflushing port are connected, and then the backflushing pipeline and the sampling tube 14 are connected, and the sampling tube 14 is backflushed.

[0060] Compared with existing backflushing operations, the backflushing method disclosed in the present invention can replace manual cleaning and maintenance, especially in high-risk environments, greatly reducing the number of manual operations. In a specific example, for a differential pressure transmitter 12 with a smaller differential pressure range, the risk of damaging the instrument due to excessive differential pressure between the high-pressure side diaphragm box 10 and the low-pressure side diaphragm box 11 during backflushing operations is eliminated. For the pressure transmitter 5, the risk of damaging the instrument due to the backflushing pressure exceeding the maximum static pressure of the diaphragm box during backflushing operations is eliminated. Increasing the backflushing pressure and reducing the backflushing time ensures the backflushing effect.

[0061] The adaptive changes according to the actual requirements are within the protection scope of the present application.

[0062] It should be noted that, for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting in any respect, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0063] The principles and implementation manners of the present application are described by using specific examples, and the above embodiment descriptions are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In conclusion, the content of the present description should not be understood as a limitation of the present application.

Claims

1. A high-pressure backflush device for an instrument sampling tube, characterized in that: Including backflush pipeline, multi-way solenoid valve and controller; The multi-way solenoid valve is provided with a communication port, a backflush port and a pressure port, the communication port is used to be connected to the sampling tube, the backflush port is connected to the air outlet end of the backflush pipeline, and the pressure port is used to be connected to the pressure monitoring instrument; The air inlet end of the backflush pipeline is used to introduce the backflush medium; The controller is electrically connected to the multi-way solenoid valve and is used to switch the communication port to be connected to the backflush port and the pressure taking port respectively.

2. The high-pressure backflushing device for instrument sampling tube according to claim 1, characterized in that: A pressure reducing valve is provided on the back-blowing pipeline.

3. The high-pressure backflushing device for instrument sampling tube according to claim 2, characterized in that: A first stop valve is provided on the backflush pipeline, and the first stop valve is located on the air inlet side of the pressure reducing valve.

4. The high-pressure backflushing device for instrument sampling tube according to claim 2, characterized in that: The pressure monitoring instrument is a pressure transmitter, and a transmitter connector of the pressure transmitter is connected to the pressure port.

5. The high-pressure backflushing device for instrument sampling tube according to claim 4, characterized in that: The transmitter connector is in threaded communication with the pressure port.

6. The high-pressure backflushing device for instrument sampling tube according to claim 2, characterized in that: The pressure monitoring instrument is a differential pressure transmitter, and the differential pressure transmitter is equipped with two multi-way solenoid valves and two sampling tubes; The three-valve group matched with the differential pressure transmitter, its high-pressure connector and low-pressure connector are respectively connected to the pressure ports of the two multi-way solenoid valves; The air outlet end of the back-blowing pipeline is connected to the back-blowing ports of the two multi-way solenoid valves through a back-blowing branch pipe; The two sampling tubes are both connected to the communication ports of the two multi-way solenoid valves.

7. The high-pressure backflushing device for instrument sampling tube according to claim 6, characterized in that: The high-pressure joint and the low-pressure joint are respectively connected to the two pressure ports through threads.

8. The high-pressure backflushing device for instrument sampling tubes according to claim 4 or 6, characterized in that: The sampling tube is provided with two second stop valves, and the two second stop valves are arranged in sequence along the flow direction of the medium in the sampling tube.

9. The high-pressure backflushing device for instrument sampling tubes according to claim 1, characterized in that: The controller is electrically connected to the pressure monitoring instrument.

10. A backflushing method, characterized in that: The high-pressure backflushing device for an instrument sampling tube according to any one of claims 1 to 9 is applied, comprising the following steps: Before backflush operation: the multi-way solenoid valve is in the first working position, the communication port and the pressure port of the multi-way solenoid valve are in a connected state, the communication port and the backflush port of the multi-way solenoid valve are in a disconnected state, and the pressure monitoring instrument monitors the real-time pressure of the sampling tube through the pressure port; During backflushing operation: the multi-way solenoid valve is in the second working position, the connecting port and the pressure taking port of the multi-way solenoid valve are disconnected, the connecting port and the backflushing port of the multi-way solenoid valve are connected, and then the backflushing pipeline and the sampling tube are connected, and the sampling tube is backflushed.

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