Closed gas path automatic dilution gas detection alarm calibrating system and calibrating method

Abstract

The closed gas path automatic dilution gas detection alarm calibrating system and method, the measurement service network platform controls the local calibration software of the CCD camera and the host computer through the Web server, sends instructions to the PLC controller through the calibration software, the PLC controller controls the rotor flowmeter, the electromagnetic valve, the motor and the gas dilution device according to the received signals, and feeds back the collected signals to the PLC controller after the action is completed, the PLC controller transmits the received signals to the calibration software for processing and judgment, the measurement service network platform adopts 5G network to quickly process the received and sent commands, the created database has data protection function and can prevent data loss and string modification, the calibration system can effectively trace the calibration results through the national secondary gas standard substance in six steel cylinders, the CCD camera monitors the on-site situation and the calibration process of the gas detection alarm in real time, and the concentration value recorded by the calibrated alarm can be obtained by processing the photographed image.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of instrument calibration, in particular to a closed gas path automatic dilution gas detection alarm calibrating system and method. BACKGROUND

[0002] The portable gas detection alarm is an instrument that can measure the concentration of specific gas in the working environment, and has sound and light alarm function. It can measure combustible, explosive and toxic and harmful gas at the same time. Users can choose different instruments according to the specific site gas leakage type. Commonly used are three-in-one and four-in-one gas detection alarms, which mainly detect combustible gas, hydrogen sulfide gas, carbon monoxide gas and oxygen. Portable gas detection alarm is mainly used in petrochemical plants and dangerous chemical storage warehouses and other environments and places where combustible and toxic and harmful gas leakage may occur. Relevant personnel wear it when entering these leakage danger areas, real-time measure whether there is gas leakage that endangers personnel safety in the environment and sound and light alarm, and the measurement performance is confirmed according to the requirements of the relevant metrology technical specifications, such as JJG 693-2011 Combustible Gas Detection Alarm, JJG 915-2008 Carbon Monoxide Detection Alarm, JJG 695-2003 Hydrogen Sulfide Gas Detector and JJG 365-2008 Electrochemical Oxygen Detector.

[0003] According to the above metrology technical specification requirements, the general metrology equipment is mainly composed of gas standard substance, flow controller, pressure reducing valve, pipeline, stopwatch and calibration cover. Its principle is that the gas standard substance in the steel cylinder is sent into the flow controller (rotary flow meter) through the pipeline, the rotary flow meter is adjusted according to the product instruction, and the gas standard substance is sent into the gas inlet of the portable gas detection alarm.

[0004] The whole process needs to be operated on site by metrology personnel. In the calibration process, the data uncertainty introduced by human factors is large and the efficiency is low, which cannot meet the calibration of a large number of portable gas detection alarms.

[0005] At present, the research on gas alarm calibration in China mainly includes the following several units. One unit in Shandong independently designs a set of toxic and harmful alarm detector device with visual recognition function, but it cannot meet the repeatability requirement of combustible gas detection regulation. In addition, China Testing Research Institute has developed an automatic detection device for detecting fixed combustible, explosive and harmful gas alarm, but it is only suitable for detecting fixed gas alarm and has low automation degree.

[0006] The above alarm detector device cannot simultaneously meet the calibration of commonly used gases in composite gas detection alarm, such as combustible gas, carbon monoxide, oxygen and hydrogen sulfide. SUMMARY

[0007] The application aims to provide a closed gas path automatic dilution gas detection alarm calibrating system and method.

[0008] In order to achieve the above-mentioned purpose, the technical scheme of the application is as follows:

[0009] The closed gas path automatic dilution gas detection alarm calibrating system comprises a metrology network service platform, a CCD camera, a gas dilution device, a measuring platform, an upper computer and a PLC controller. The measuring platform comprises an upper layer cabinet and a lower layer cabinet, and the upper layer cabinet and the lower layer cabinet are separated by a partition. A plurality of standard gas storage bottles are arranged on one side of the lower layer cabinet. A placing cabinet is arranged on one side of the upper layer cabinet. The gas dilution device is arranged in the middle of the upper layer cabinet. The standard gas storage bottles are communicated with the gas inlet of the gas dilution device through a gas conveying pipeline. The gas dilution device is fixed to the upper end of a sealing support. The lower end of the sealing support is fixedly connected with the upper end of the partition. A double-layer rotary workbench is arranged in the sealing support. The rotary workbench is driven to rotate by a motor. The gas outlet of the gas dilution device is connected with a single-channel side of a three-way pipe. The double-channel side of the three-way pipe is respectively communicated with the gas detection alarm gas inlets of the upper and lower layers of the rotary workbench. The upper computer and the PLC controller are arranged on the other side of the upper layer cabinet. The upper computer and the CCD camera are in communication connection with the metrology network service platform through a Web server. The PLC controller is controlled by the upper computer. The signal ends of the PLC controller, the motor and the gas dilution device are connected. An air pump and a gas discharge device are arranged in the middle of the lower layer cabinet. An exhaust valve is arranged on the partition. The air pumping pipeline of the air pump is communicated with the inside of the sealing support through the exhaust valve.

[0010] Further, a pressure reducing valve is arranged at the gas outlet of each standard gas storage bottle. The gas outlet of the pressure reducing valve is connected with the gas inlet end of the gas conveying pipeline.

[0011] Further, a rotor flowmeter is arranged in each gas conveying pipeline. An electromagnetic valve is arranged at the gas outlet end of each gas conveying pipeline. The signal ends of the rotor flowmeter and the electromagnetic valve are connected with the PLC controller.

[0012] Further, the gas outlets of all the gas conveying pipelines are connected with the gas inlet of a gas converging tank. The gas outlet of the gas converging tank is connected with the gas inlet of the gas dilution device. The gas converging tank and the rotor flowmeter are arranged in the same plane.

[0013] Further, the gas detection alarms are installed at equal intervals on the circumference with the rotary workbench rotating shaft as the center and the rotary workbench diameter quarter distance as the radius.

[0014] The portable gas detection alarm calibrating method based on the closed gas path automatic dilution comprises the following steps:

[0015] Step S1) The metrology network service platform accesses the calibration software in the host computer through the Web server, edits the current calibration parameters in the calibration software through the metrology network platform, and places the calibrated gas detection alarm in the lower two layers of the rotating workbench;

[0016] Step S2) Open the CCD camera to monitor the scene, adjust the CCD camera to clearly display the information on the gas detection alarm display screen, and adjust the motor, electromagnetic valve, rotor flowmeter and gas dilution device in the calibration software;

[0017] Step S3) Open the six standard gas storage bottle pressure reducing valves, open the electromagnetic valves corresponding to the oxygen and 99.999% high-purity nitrogen gas storage bottles through the metrology network service platform, start the gas dilution device and preheat for more than 30 minutes, adjust the rotor flowmeter to make the flow in the oxygen and nitrogen pipelines reach 500 mL / min and 1000 mL / min respectively, and after the adjustment is completed and stable, control the concentration of the input oxygen standard substance and nitrogen standard substance through the metrology network service platform, and set the dilution concentration value;

[0018] Step S4) Start the gas dilution device, open the motor when the gas dilution device reaches the set oxygen concentration, rotate the rotating workbench at a certain speed to make the sealed support uniformly filled with diluted oxygen, and open the exhaust gas discharge device;

[0019] Step S5) The CCD camera captures the oxygen concentration displayed by the gas detection alarm, and the average value of three concentration values of each calibrated gas detection alarm is imported into the corresponding database of the calibration software;

[0020] Step S6) After recording all the calibrated gas detection alarms, close the gas dilution device, electromagnetic valve and rotor flowmeter of the oxygen pipeline, and close the exhaust gas discharge device after the oxygen concentration in the sealed support returns to 20.9%, so that the sealed support continues to be in a closed state;

[0021] Step S7) Open the electromagnetic valve corresponding to the hydrogen sulfide gas storage bottle, adjust the rotor flowmeter to make the pipeline flow reach about 500 mL / min, keep the nitrogen pipeline flow at 1000 mL / min, control the concentration of the input hydrogen sulfide gas standard substance and nitrogen standard substance through the metrology network service platform, and input the dilution concentration value, then replace the oxygen with carbon monoxide and methane, and repeat steps S4-S6;

[0022] Step S8) After completing all gas calibration, close all pressure reducing valves and gas dilution devices, open the exhaust valve and exhaust pump, and discharge the exhaust gas to a safe area through the gas discharge device;

[0023] Step S9) importing various gas data results recorded in the calibration software into the calibration certificate template, calculating through corresponding formulas and issuing the calibration certificate.

[0024] Further, in the step S1, the calibration parameters include the number of the gas detection alarm to be calibrated, the nameplate information of the gas detection alarm, the ambient temperature and humidity.

[0025] Further, the other gases include hydrogen sulfide, carbon monoxide and combustible gas.

[0026] The calibration system of the present application adopts a double-layer automatic rotating platform structure, can place multiple gas detection alarms at the same time, improves the calibration efficiency, the multi-path gas conveying gas path can perform calibration of multiple gas types, the whole device adopts airtight and explosion-proof structure, and the waste gas discharge device is installed in the middle of the lower layer of the measuring platform of the calibration device, effectively preventing the leakage of toxic and harmful gases from causing harm to personnel;

[0027] The remote metering service platform of the present application can communicate and transmit data with the local CCD camera, upload the photographed alarm data, and can access the online monitoring and control of the whole calibration process of the gas detection alarm through the network. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a front structure schematic diagram of the measuring platform of the present application;

[0029] Figure 2 It is a side structure schematic diagram of the measuring platform of the present application;

[0030] Figure 3 It is a structure schematic diagram of the gas conveying gas path and the rotating workbench of the present application;

[0031] Figure 4 It is a three-dimensional structure schematic diagram of the measuring platform of the present application;

[0032] Figure 5 It is a system structure schematic diagram of the present application.

[0033] REFERENCE NUMERALS:

[0034] 1 standard gas storage bottle, 2 placing cabinet, 3 pressure reducing valve, 4 rotameter, 5 gas dilution device,

[0035] 6 measuring platform, 61 upper layer cabinet, 62 lower layer cabinet,

[0036] 7 waste gas discharge device, 8 upper computer, 9 PLC controller, 10 sealing support,

[0037] 11 three-way pipe, 12 gas detection alarm, 13 gas manifold tank, 14 electromagnetic valve,

[0038] 15 Gas delivery path, 16 Motor, 17 Rotary worktable. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] This invention discloses a portable gas detection alarm calibration system based on automatic dilution in a closed gas path, including a metering network service platform, a CCD camera, a gas dilution device 5, a measurement platform 6, a host computer 8, and a PLC controller 9, such as... Figure 1 As shown, the measurement platform 6 includes an upper cabinet 61 and a lower cabinet 62, which are separated by a stainless steel partition. A number of standard gas storage cylinders 1 are provided on one side of the lower cabinet 62, and a placement cabinet 2 is provided on one side of the upper cabinet 61. The gas dilution device 5 is located in the middle of the upper cabinet 61 and is fixed to the upper end of the sealing bracket 10. The lower end of the sealing bracket 10 is fixedly connected to the upper end of the partition.

[0041] The standard gas storage cylinder 1 is connected to the inlet of the gas dilution device 5 via a gas delivery pipeline. In use, the outlets of all gas delivery pipelines 15 are connected to the inlet of a gas manifold 13. Figure 3 As shown, the outlet of the gas manifold 13 is connected to the inlet of the gas dilution device 5, and the gas manifold 13 and the rotor flow meter 4 are located on the same plane.

[0042] like Figure 2 and Figure 3 As shown, the sealed bracket 10 is equipped with a double-layered rotating worktable 17. The rotating worktable 17 is driven to rotate by the motor 16. The outlet of the gas dilution device 5 is connected to the single-channel side of the three-way pipe 11. The double-channel side of the three-way pipe 11 is connected to the inlet of the gas detection alarm 12 on the upper and lower layers of the rotating worktable 17, respectively. The gas detection alarm 12 is installed at equal intervals on the circumference with the rotation axis of the rotating worktable 17 as the center and a radius of one-quarter of the diameter of the rotating worktable 17.

[0043] like Figure 4As shown, the host computer 8 and the PLC controller 9 are installed on the other side of the upper cabinet 61, and the host computer 8 and the CCD camera can be connected in communication with the metering network service platform through the Web server, the host computer 8 is installed with calibration software, the host computer 8 can control the CCD camera and the PLC, and a calibration report can be issued, the PLC controller 9 is connected with the signal end of the motor 16 and the gas dilution device 5, and the signal output end of the CCD camera is connected in communication with the hard disk storage of the host computer 8.

[0044] The gas outlet of each standard gas storage bottle 1 is provided with a pressure reducing valve 3, the gas outlet of the pressure reducing valve 3 is connected with the gas inlet end of the gas delivery gas path 15, each gas delivery gas path 15 is provided with a rotor flow meter 4, and the gas outlet end of each gas delivery gas path 15 is provided with an electromagnetic valve 14, and the signal ends of the rotor flow meter 4 and the electromagnetic valve 14 are connected with the PLC controller 9.

[0045] The middle part of the lower cabinet 62 is provided with an air suction pump and a gas discharge device, the partition plate is provided with an exhaust valve, and the air suction pipeline of the air suction pump is communicated with the inside of the sealed support 10 through the exhaust valve.

[0046] As shown in the figure, Figure 5 The metering service network platform controls the local calibration software of the CCD camera and the host computer 8 in real time through the Web server, sends instructions to the PLC controller 9 through the calibration software, the PLC controller 9 controls the rotor flow meter 4, the electromagnetic valve 14, the motor 16 and the gas dilution device 5 to act according to the received signal, and after the action is completed, the collected signal is fed back to the PLC controller 9, the PLC controller 9 transmits the received signal to the calibration software for processing and judgment, the metering service network platform uses 5G network to quickly process the received and sent commands, the created database has data protection function and can prevent data loss and tampering, and the calibration system can effectively trace the calibration result through the national secondary gas standard substance in six steel cylinders.

[0047] The Web server can control the calibration software and the CCD camera through a mobile phone and a computer network terminal, the CCD camera can monitor the on-site situation of the gas detection alarm 12 and the calibration process in real time, and can record the concentration value of the calibrated gas detection alarm 12 by processing the photographed image.

[0048] The portable gas detection alarm calibration method based on the automatic dilution of the closed gas path comprises the following steps:

[0049] Step S1) The calibration software in the host computer 8 is accessed by the metrology network service platform through the Web server, the current calibration parameters are edited in the calibration software through the metrology network platform, the calibration parameters include the number of the calibrated gas detection alarm 12, the nameplate information of the gas detection alarm 12, the environmental temperature and humidity, the calibrated gas detection alarm 12 normally running after starting is placed in the upper and lower two layers of the rotating workbench 17;

[0050] Step S2) The CCD camera is opened to monitor the on-site situation, the CCD camera is debugged to clearly display the information on the display screen of the gas detection alarm 12, the motor 16, the electromagnetic valve 14, the rotor flowmeter 4 and the gas dilution device 5 are debugged in the calibration software;

[0051] Step S3) The six standard gas storage bottles 1 are opened, the oxygen and 99.999% high-purity nitrogen storage bottles corresponding electromagnetic valves 14 are opened through the metrology network service platform, the gas dilution device 5 is started and preheated for more than 30 minutes, the rotor flowmeter 4 is adjusted to make the flow rates in the oxygen and nitrogen pipelines reach 500 mL / min and 1000 mL / min respectively, the concentration of the input oxygen standard substance and nitrogen standard substance is controlled through the metrology network service platform, and the dilution concentration value is set;

[0052] Step S4) The gas dilution device 5 is started, the motor 16 is opened after the gas dilution device 5 reaches the set oxygen concentration, the rotating workbench 17 rotates at a certain speed, the sealed support 10 is uniformly filled with diluted oxygen, and the waste gas discharge device 7 is opened;

[0053] Step S5) The CCD camera captures the oxygen concentration displayed by the gas detection alarm 12, the concentration value is captured three times for each calibrated gas detection alarm 12, and the average value is input into the corresponding database in the calibration software;

[0054] Step S6) After the records of all the calibrated gas detection alarms 12 are completed, the gas dilution device 5, the electromagnetic valve 14 of the oxygen pipeline and the rotor flowmeter 4 are closed, the waste gas discharge device 7 is closed after the oxygen concentration in the sealed support 10 returns to 20.9%, and the sealed support 10 continues to be in a closed state;

[0055] Step S7) The electromagnetic valves 14 corresponding to other gas storage bottles are opened, the rotor flowmeter 4 is adjusted to make the pipeline flow rate reach about 500 mL / min, the nitrogen pipeline flow rate is kept at 1000 mL / min, after the debugging is completed and stabilized, the concentration of the input other gas standard substance and nitrogen standard substance is controlled through the metrology network service platform, and the dilution concentration value is input, then hydrogen sulfide, carbon monoxide and combustible gas are used to replace oxygen in turn, and steps S4-S6 are cycled;

[0056] Step S8) After all the gas calibration is completed, close all the pressure reducing valves 3 and the gas dilution device 5, open the exhaust valve and the exhaust pump, and discharge the exhaust gas to a safe area through the gas discharge device;

[0057] Step S9) Import the various gas data results recorded in the calibration software into the calibration certificate template, calculate through the corresponding formula, and issue the calibration certificate.

[0058] The tee pipe 11 of the application is made of polytetrafluoroethylene, and the measuring platform 6, the gas conveying pipeline 15, the sealing support 10 and the gas collecting tank 13 are made of stainless steel.

[0059] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A closed-circuit automatic dilution gas detection alarm calibration system, characterized in that, The system includes a metering network service platform, a CCD camera, a gas dilution device, a measurement platform, a host computer, and a PLC controller. The measurement platform comprises an upper cabinet and a lower cabinet, separated by a partition. One side of the lower cabinet houses several standard gas storage cylinders, and one side of the upper cabinet houses a storage cabinet. The gas dilution device is located in the middle of the upper cabinet. The standard gas storage cylinders are connected to the inlet of the gas dilution device via gas delivery pipelines. The gas dilution device is fixed to the upper end of a sealed support, and the lower end of the sealed support is fixedly connected to the upper end of the partition. The sealed support contains a double-layer... The rotating worktable is driven by a motor. The outlet of the gas dilution device is connected to the single-channel side of a three-way pipe, and the dual-channel side of the three-way pipe is connected to the gas detection alarm inlets on the upper and lower layers of the rotating worktable, respectively. The host computer and PLC controller are located on the other side of the upper cabinet. The host computer and CCD camera are both connected to the metering network service platform via a web server. The PLC controller is controlled by the host computer and is connected to the signal terminals of the motor and the gas dilution device. A vacuum pump and a gas emission device are located in the middle of the lower cabinet. The partition is equipped with... The system includes an exhaust valve, and the exhaust pipe of the air pump is connected to the interior of the sealed support via the exhaust valve. Each standard gas storage cylinder has a pressure reducing valve at its outlet, and the outlet of the pressure reducing valve is connected to the inlet of the gas delivery path. Each gas delivery path is equipped with a rotor flow meter, and each gas delivery path has a solenoid valve at its outlet. The signal terminals of the rotor flow meter and the solenoid valve are connected to a PLC controller. The outlets of all gas delivery paths are connected to the inlet of a gas manifold, and the outlet of the gas manifold is connected to the inlet of a gas dilution device. The gas manifold and the rotor flow meter are located in the same location. In a planar configuration, the gas detectors are evenly spaced on a circle with the rotating axis of the rotating table as the center and a radius equal to one-quarter of the diameter of the rotating table. The metering network service platform controls the CCD camera and the local calibration software on the host computer in real time via a web server. The calibration software sends instructions to the PLC controller, which controls the rotor flow meter, solenoid valve, motor, and gas dilution device to perform actions based on the received signals. After the actions are completed, the collected signals are fed back to the PLC controller, which then transmits the received signals to the calibration software for processing and judgment.

2. A calibration method for an automatic dilution gas detection alarm in a closed gas path, characterized in that, Includes the following steps: Step S1) The metrology network service platform accesses the calibration software in the host computer through the Web server, edits the current calibration parameters in the calibration software through the metrology network platform, and places the gas detector alarm under calibration, which is powered on and running normally, in the upper and lower layers of the rotating workbench. Step S2) Turn on the CCD camera to monitor the scene, adjust the CCD camera to clearly display the information on the gas detector alarm display screen, and adjust the motor, solenoid valve, rotor flow meter and gas dilution device in the calibration software; Step S3) Open the pressure reducing valves of the six standard gas storage bottles, and open the solenoid valves corresponding to the oxygen and 99.999% high-purity nitrogen storage bottles through the metering network service platform. The gas dilution device is turned on and preheated for more than 30 minutes. Adjust the rotor flow meter to make the flow rates in the oxygen and nitrogen pipelines reach 500 mL / min and 1000 mL / min respectively. After the debugging is completed and stabilized, control the input concentration of oxygen standard material and nitrogen standard material through the metering network service platform, and set the dilution concentration value. Step S4) Start the gas dilution device. After the gas dilution device reaches the set oxygen concentration, turn on the motor and rotate the worktable at a certain speed to make the sealed support uniformly filled with diluted oxygen. Then turn on the exhaust gas emission device. Step S5) The CCD camera captures the oxygen concentration displayed by the gas detector alarm. The concentration value of each gas detector alarm to be calibrated is captured three times and the average value is taken and imported into the corresponding database of the calibration software. Step S6) After recording all the gas detectors under calibration, close the gas dilution device, the solenoid valve of the oxygen pipeline and the rotor flow meter. After the oxygen concentration in the sealed bracket recovers to 20.9%, close the exhaust gas emission device to keep the sealed bracket in a sealed state. Step S7) Open the solenoid valve corresponding to the other gas storage bottle. The other gases include hydrogen sulfide, carbon monoxide and combustible gas. Adjust the rotor flow meter to make its pipeline flow reach about 500 mL / min. Keep the nitrogen pipeline flow at 1000 mL / min. Control the input concentration of other gas standard substances and nitrogen standard substances through the metering network service platform, and input the dilution concentration value. Then replace oxygen with hydrogen sulfide, carbon monoxide and combustible gas in sequence, and repeat steps S4 to S6. Step S8) After completing all gas calibrations, close all pressure reducing valves and gas dilution devices, open the exhaust valves and vacuum pumps, and discharge the exhaust gas to a safe area through the gas emission device. Step S9) Import the various gas data results recorded in the calibration software into the calibration certificate template, calculate and issue the calibration certificate through the corresponding formula. In step S1, the calibration parameters include the number of gas detectors to be calibrated, the nameplate information of the gas detectors, and the ambient temperature and humidity.

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