CN116212727A - High-precision intelligent dynamic air distribution system and air distribution method thereof - Google Patents
High-precision intelligent dynamic air distribution system and air distribution method thereof Download PDFInfo
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- CN116212727A CN116212727A CN202310075919.6A CN202310075919A CN116212727A CN 116212727 A CN116212727 A CN 116212727A CN 202310075919 A CN202310075919 A CN 202310075919A CN 116212727 A CN116212727 A CN 116212727A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/22—Control or regulation
- B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
- B01F35/2211—Amount of delivered fluid during a period
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/10—Mixing gases with gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/10—Maintenance of mixers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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Abstract
The invention designs a high-precision intelligent dynamic air distribution system and an air distribution method thereof, which can improve the control precision of standard air and dilution air flow, reduce the residual of an internal pipeline of a dynamic dilution instrument and reduce the drift influence caused by long-term operation of the dynamic dilution instrument, thereby improving the calibration accuracy of an analysis instrument. The invention adopts the electromagnetic proportional valve, the pressure sensor and the air resistor to carry out closed-loop control on the gas flow, and can greatly improve the detection precision of small-flow gas by using the pressure as the flow detection parameter. The detection precision of the pressure sensor is higher than that of the traditional mass flow sensor; according to the invention, an automatic purging and cleaning method is adopted, so that all pipelines of the dynamic diluting instrument can be purged and cleaned before each sample injection while the use of various standard gases is met, the cross contamination of samples is avoided, and the accuracy is improved; the invention adopts the automatic calibration method of the flow control module, and can effectively avoid the drift problem of the flow control module caused by long-term operation.
Description
Technical Field
The invention relates to the technical field of dynamic air distribution systems, in particular to a high-precision intelligent dynamic air distribution system and an air distribution method thereof.
Background
The dynamic air distribution system is widely applied to the fields of instrument research and development, environmental air monitoring and the like at present, and is prepared into standard air with different gradient concentrations by using high-concentration standard air and is used for calibrating laboratory analysis instruments and environmental air on-line detection equipment, and the accuracy of instrument calibration mainly depends on the repeatability and long-term stability of the dynamic air distribution system. At present, a plurality of mass flow controllers are generally adopted in a dynamic gas distribution system in the market to respectively control the flow of standard gas and the flow of diluent gas, so that the standard gas and the diluent gas are mixed according to a certain proportion to prepare the standard gas. The existing dynamic air distribution system has the following defects in actual application:
1. the existing dynamic gas distribution system generally adopts a mass flow controller to detect and control the flow of standard gas or diluent gas, but the control precision of the mass flow controller is influenced by the detection precision and the measuring range of a mass flow sensor of the mass flow controller, and the dynamic gas distribution system has the following characteristics: 1. the larger the measuring range of the mass flow sensor is, the lower the detection precision is; 2. the mass flow sensor has a minimum detection value, and when the detection flow is smaller than the minimum detection value, the detection accuracy is greatly reduced; 3. the higher the detection accuracy of the mass flow sensor, the higher the cost. And the flow sensor measurement is affected by temperature or pressure, and drift exists in long-term use.
2. At present, a plurality of environmental air detection devices are usually arranged in an environmental detection station room, and a dynamic air distribution system usually uses a plurality of standard gases for calibrating the plurality of environmental air detection devices. When the dynamic gas distribution system switches standard gas, residues exist in the internal pipeline of the dynamic gas distribution system, so that the calibration accuracy of the analysis instrument is reduced. The self-cleaning function of the existing dynamic air distribution system generally only cleans the rear end pipeline of the mass flow controller, and the front end pipeline still has residues, so that the standard gas is polluted, and the calibration accuracy of an analysis instrument is reduced.
Disclosure of Invention
In order to solve the technical problems, the invention designs the high-precision intelligent dynamic gas distribution system and the gas distribution method thereof, which can improve the control precision of standard gas and dilution gas flow, reduce the residual of the internal pipeline of the dynamic gas distribution system and reduce the drift influence caused by long-term operation of the dynamic gas distribution system, thereby improving the calibration accuracy of an analysis instrument.
The invention adopts the following technical scheme:
the high-precision intelligent dynamic gas distribution system is characterized by comprising a sample injection valve module, a flow control module, a gas mixing module, an output valve module, a circuit control module, a case and a display operation module, wherein at least 3 gas input ports and 2 gas output ports are arranged on the surface of the case; the gas input port is respectively connected with standard gas, purge gas and diluent gas; the gas outlets are respectively connected with different detection devices;
the sample injection valve module is provided with at least two paths of input flow paths and 1 path of output flow paths, and the input flow paths are provided with electromagnetic valves for switching different input flow paths and controlling different standard gases or purge gases to enter the inside of the instrument; the output flow path is provided with a pressure sensor for measuring the pressure of the input gas;
the flow control module is provided with at least 2 flow control components, at least 1 flow control component is connected with the sample injection valve module and the gas mixing module and used for controlling the input flow of standard gas, and at least 1 flow control component is connected with the dilution gas and the gas mixing module and used for controlling the input flow of dilution gas;
the flow control assembly is used for forming closed-loop control on the flow of the gas by the MCU, the detection module and the execution module;
the gas mixing module is provided with at least two gas input ports for communicating with a flow control assembly on the flow control module;
the detection module is used for detecting the gas flow, feeding back a detection signal to the MCU, processing the detection signal into a flow signal by the MCU, feeding back an adjustment signal to the execution module, and adjusting the output flow of the pipeline according to the signal;
the output valve module is provided with 1 path of input flow path and at least 2 paths of output flow path, the input flow path is provided with a detection element for detecting total flow of output gas, and the output flow paths are provided with electromagnetic valves for controlling the output gas to enter the set detection equipment.
Preferably, the electromagnetic valve of the sample injection valve module is at least 1 two-position three-way electromagnetic valve or two-position five-way electromagnetic valve or three-position five-way electromagnetic valve or at least 1 two-position three-way electromagnetic valve or two-position five-way electromagnetic valve or three-position five-way electromagnetic valve.
Preferably, the execution module is an electromagnetic proportional valve, and the detection module includes: pressure sensor and air resistance.
Preferably, the air resistor is a back pressure element for forming stable air resistor, and the back pressure element is ruby air resistor or small-caliber stainless steel pipeline or capillary column.
The gas distribution method of the high-precision intelligent dynamic gas distribution system comprises the following steps:
s1: after the dynamic air distribution system is started, communication and air tightness check are automatically executed, and the flow control module is automatically calibrated;
s2: according to the test method, setting a test sequence and an automatic maintenance period, wherein each row of sequence is provided with a standard gas type, a standard gas concentration, an output gas total flow, an output gas concentration and an output port type, and the execution times are counted, and the MCU automatically calculates the standard gas flow and the dilution gas flow according to set parameters;
s3: after the self-checking is finished, the sample injection valve module enters a purging mode, and after the self-cleaning operation is finished, the sample injection valve module is switched to a sample injection mode;
s4: the flow control module adjusts the flow of the standard gas and the flow of the diluent gas to set values and outputs the set values to the gas mixing module respectively;
s5: the gas is mixed and then output to the output valve module, and the output valve module controls the switch of the electromagnetic valve according to the set output port to enable the mixed gas to be output from the set output port.
Preferably, the automatic calibration method of the flow control module in step S1 comprises the following steps:
a1, the output valve module closes other output ports and opens a calibration output flow path;
a2, setting 0% opening amount of the electromagnetic proportional valve, and measuring output flow;
a3, if the output flow is not stable for a certain time, judging that self-calibration fails, and outputting the opening degree of the proportional valve and the actual test flow;
a4, if the output flow is stable, the flow calibration equipment uploads the detected flow to the MCU;
a5, the MCU records the output flow, sends out a proportional valve adjusting signal, adjusts the opening amount of the proportional valve at certain intervals, and measures the output flow of the next calibration point;
a6, the MCU records the flow of all calibration points within the opening range of 0-99% of the proportional valve, and draws a calibration curve;
and a7, the flow control module completes calibration.
Preferably, the automatic calculation flow of the target air flow and the diluent air flow in step S2 is as follows:
a1, the MCU receives the set standard gas concentration, the total output gas flow and the output gas concentration;
a2, MCU according to the formula: the mixture gas concentration=target gas flow X target gas concentration/(target gas flow+diluent gas flow) the target gas flow and the diluent gas flow are automatically calculated.
Preferably, in step S3, the sample injection valve module switches the purge mode and the sample injection mode through a two-position three-way electromagnetic valve.
Preferably, the specific steps of step S3 are:
b1, the MCU sends a valve cutting signal to a two-position three-way electromagnetic valve, and the sample injection valve module enters a purging mode;
b2, blocking the standard gas by a two-position three-way electromagnetic valve, and enabling the purge gas to sequentially pass through the two-position three-way electromagnetic valve, the flow control module, the gas mixing module and the output valve module to finish self-cleaning operation;
b3, after self-cleaning is finished, the MCU sends a valve cutting signal to the two-position three-way electromagnetic valve, and the sample injection valve is switched to a sample injection mode;
and B4, blocking the purge gas by a two-position three-way electromagnetic valve, sequentially passing through the two-position three-way electromagnetic valve and the flow control module, mixing the standard gas with the diluent gas in the gas mixing module, and outputting the mixed gas to the output valve module to finish the sample injection operation.
Preferably, in step S4, the flow control module adjusts the flow of the standard gas and the diluent gas by adopting a closed-loop flow control mode based on a pressure sensor, and the specific implementation mode is as follows:
c1, starting air distribution by an instrument, receiving a set flow value by an MCU, and converting the flow value into a theoretical pressure value according to a built-in program;
c2, opening an electromagnetic proportional valve and outputting gas, and detecting an actual pressure value of the front end of the air resistor by a pressure sensor and uploading the actual pressure value to the MCU;
c3, the MCU judges whether the difference value between the theoretical pressure value and the actual pressure value is smaller than a threshold value;
if the difference value is smaller than the threshold value, the electromagnetic proportional valve maintains the state, and the pressure sensor continuously monitors the pressure of the front end of the air resistor until the air distribution is finished;
if the difference value is larger than the threshold value, the electromagnetic proportional valve adjusts the opening amount of the electromagnetic proportional valve according to the difference value, so that the difference value between the theoretical pressure value and the actual pressure value is smaller than the threshold value;
and C6, if the electromagnetic proportional valve is continuously adjusted for 5s-60s and the difference value is not smaller than the threshold value, judging the instrument to be faulty and prompting an alarm.
The beneficial effects of the invention are as follows: (1) The invention adopts the electromagnetic proportional valve, the pressure sensor and the air resistor to carry out closed-loop control on the gas flow, and the pressure is used as a flow detection parameter, so that the detection precision of the small-flow gas can be greatly improved; the detection precision of the pressure sensor is higher than that of the traditional mass flow sensor; (2) The automatic purging and cleaning method is adopted, so that all pipelines of the dynamic gas distribution system can be purged and cleaned before each sample injection while the use of various standard gases is met, cross contamination of samples is avoided, and the accuracy is improved; (3) The invention adopts an automatic calibration method of the flow control module, and can effectively avoid the drift problem of the flow control module caused by long-term operation.
Drawings
FIG. 1 is a schematic illustration of a gas distribution system of the present invention;
FIG. 2 is a schematic diagram of a flow control module of the gas distribution system of the present invention;
FIG. 3 is a schematic diagram of a structure for switching between purge mode and sample injection mode in the present invention;
FIG. 4 is a schematic diagram of two standard gas feeds in the present invention;
FIG. 5 is a schematic diagram of four standard gas feeds in the present invention;
FIG. 6 is a flow control diagram of automatic calibration of a flow control module in accordance with the present invention;
FIG. 7 is a flow control diagram of a closed loop flow control scheme based on a pressure sensor in accordance with the present invention;
in the figure: 1. the device comprises a case, 2, a sample injection valve module, 3, a flow control module, 4, a standard gas control module, 5, a dilution gas control module, 6, a gas mixing module, 7, a circuit control module, 8, a display operation module, 9, an output valve module, 10, a calibration gas output port, 11, an output gas interface, 12, a flow control module, 13, an analysis instrument, 14, a dilution gas source, 15, a dilution gas input port, 16, a standard gas source, 17, a standard gas input port, 18, a purge gas source, 19, a purge gas input port, 20, a calibration circuit interface, 21, a standard gas actuator, 22, a standard gas detection element, 23, a standard gas resistor, 24, a flow control PCB,25, a dilution gas resistor, 26, a dilution gas detection element, 27, a standard gas actuator, 201, a two-position three-way electromagnetic valve, 202, a two-position five-way electromagnetic valve, 203, a two-position three-way electromagnetic valve, 204, a three-position three-way electromagnetic valve, 204 and three-position three-way electromagnetic valve.
Description of the embodiments
Examples
As shown in fig. 1, the embodiment of the invention provides a high-precision intelligent dynamic gas distribution system, which comprises a sample injection valve module, a flow control module, a gas mixing module, an output valve module, a circuit control module, a chassis and a display operation module. The display operation module is used for setting system parameters and operation sequences; the surface of the case 1 is provided with a standard gas input port, a purge gas input port, a diluent gas input port and two gas output ports, wherein the two gas output ports are respectively connected with an analysis instrument and flow calibration equipment; the sample valve module 2 is respectively connected with the standard gas input port, the purge gas input port, the power supply control module 7 and the flow control module 3 and is used for switching different input flow paths and automatically switching the standard gas and the purge gas to enter the flow control module 3.
As shown in fig. 2, the flow control module 3 is provided with a standard air flow control assembly 4, a dilution air flow control assembly 5 and a flow control PCB23, and the flow control PCB23 is connected with the circuit control module 7 and is used for receiving and transmitting detection signals and control signals of detection elements on the flow control module 3 and controlling execution elements on the flow control module 3; after entering the standard gas flow control assembly 4, the standard gas sequentially enters a gas mixing module through a standard gas executing element 20, a standard gas detecting element 21 and a standard gas resistor 22; the standard gas executing element 20 is an electromagnetic proportional valve, is connected with an output port of the sample injection valve module 3 and the flow control PCB23, and is used for controlling the flow of the standard gas entering the gas mixing module; the standard gas detection element 21 is a pressure sensor and is connected with the flow control PCB23 for detecting the gas pressure generated when the standard gas passes through the standard gas resistor 22; the standard gas lock 22 is used to create a stable gas pressure and flow; after entering the dilution gas flow control assembly 5, the dilution gas sequentially enters a gas mixing module through a dilution gas executing element 26, a dilution gas detecting element 25 and a dilution gas resistor 24; the dilution gas executing element 26 is an electromagnetic proportional valve, is connected with the dilution gas input port 15 and the flow control PCB23, and is used for controlling the flow of the dilution gas entering the gas mixing module; the diluent gas detecting element 25 is a pressure sensor and is connected with the flow control PCB23 for detecting the gas pressure generated when the diluent gas passes through the diluent gas resistor 24; the dilution gas lock 24 is used to create a stable gas pressure and flow; the diluted gas and the standard gas are fully mixed in the gas mixing module and then enter the output valve module; the output valve module is provided with an input flow path and two output flow paths, the input flow path is provided with a detection element for detecting the total flow of output gas, and the output flow paths are provided with electromagnetic valves for controlling the output gas to enter the set detection equipment.
Specifically, as shown in fig. 3, in this embodiment, the sample valve module 2 is composed of a two-position three-way electromagnetic valve 201, two input ports of the two-position three-way electromagnetic valve are respectively connected with the standard gas input port 17 and the scavenging gas input port 19, the output port is connected with the flow control module 3, and the flow path in the valve is switched to the corresponding input port according to the set parameters, so that the sample valve module 2 is switched to the sample mode to control the standard gas to enter the flow control module 3 or the sample valve module 2 is switched to the purge mode to control the purge gas to enter the flow control module 3. Specifically, after the sample valve module 2 enters the purging mode, the purging gas enters the gas mixing module 6 through the sample valve module 2 and the flow control module 3 to be mixed with the diluent gas, and is output to a corresponding analysis instrument through the output valve module 9, so that all pipelines in the dynamic gas distribution system are purged, and the pipeline residues in the dynamic gas distribution system are reduced.
Further, as shown in fig. 4, the present invention may provide a sample injection method for 2 different kinds of standard gases, where the sample injection valve module 2 is a combined valve set formed by a two-position three-way electromagnetic valve 201 and a two-position five-way electromagnetic valve 202, three input ports of the two-position five-way electromagnetic valve 202 are respectively connected with a standard gas one, a standard gas two and a purge gas, two output ports are respectively connected with two input ports of the two-position three-way electromagnetic valve 201, and an output port of the two-position three-way electromagnetic valve 201 is connected with the flow control module 3. Specifically, before the first standard gas is sampled, the sample valve module 2 enters a first standard gas purging mode, the two-position five-way electromagnetic valve 202 and the two-position three-way electromagnetic valve 201 switch internal flow paths, so that two output ports of the two-position five-way electromagnetic valve 202 are communicated with the second standard gas and purge gas, namely the first standard gas is blocked by the two-position five-way electromagnetic valve 202, the second standard gas is blocked by the two-position three-way electromagnetic valve 201, and purge gas purges all pipelines in the sample valve module 2 through which the first standard gas needs to pass; after the purging of the standard gas I is completed, the sample injection valve module 2 enters a standard gas I sample injection mode, the two-position five-way electromagnetic valve 202 switches an internal flow path, so that two output ports of the two-position five-way electromagnetic valve 202 are communicated with the standard gas I and the purge gas, namely the standard gas II is blocked by the two-position five-way electromagnetic valve 202, the purge gas is blocked by the two-position three-way electromagnetic valve 201, and the standard gas I enters the flow control module 3; after the sample injection of the standard gas I is finished, the sample injection valve module 2 enters a standard gas II purging mode, the two-position three-way electromagnetic valve 201 switches an internal flow path, so that two output ports of the two-position five-way electromagnetic valve 202 are communicated with the standard gas I and purging gas, namely the standard gas II is blocked by the two-position five-way electromagnetic valve 202, the standard gas I is blocked by the two-position three-way electromagnetic valve 201, and the purging gas purges all pipelines in the sample injection valve module 2 through which the standard gas II needs to pass; after the purging of the standard gas II is completed, the sample injection valve module 2 enters a standard gas II sample injection mode, the two-position five-way electromagnetic valve 202 switches an internal flow path, so that two output ports of the two-position five-way electromagnetic valve 202 are communicated with the standard gas II and the purge gas, namely, the standard gas I is blocked by the two-position five-way electromagnetic valve 202, the purge gas is blocked by the two-position three-way electromagnetic valve 201, and the standard gas I enters the flow control module 3.
Particularly, when the standard gas is switched every time, the sample valve module 2 enters a purging mode to purge a valve internal flow path and a connecting pipeline inside the sample valve, so that the mutual pollution of different types of standard gas is avoided. Meanwhile, the purging gas is used for isolating the first standard gas from the second standard gas, so that the problem of standard gas source pollution caused by valve leakage when various standard gases are used is avoided.
Further, as shown in fig. 5, the present invention provides a sample injection method for 4 different kinds of standard gases, and the sample injection valve module 2 is a combined valve set formed by a two-position three-way electromagnetic valve 201, a two-position three-way electromagnetic valve 203, a three-position five-way electromagnetic valve 204 and a three-position five-way electromagnetic valve 205; the three input ports of the three-position five-way electromagnetic valve 205 are respectively connected with the standard gas I, the standard gas II and the purge gas, the two output ports are respectively connected with the two input ports of the two-position three-way electromagnetic valve 201, and the output port of the two-position three-way electromagnetic valve 201 is connected with the output port of the two-position three-way electromagnetic valve 202 and the flow control module 3; the three input ports of the three-position five-way electromagnetic valve 204 are respectively connected with the standard gas I, the standard gas II and the purge gas, the two output ports are respectively connected with the two input ports of the two-position three-way electromagnetic valve 202, and the output port of the two-position three-way electromagnetic valve 202 is connected with the output port of the two-position three-way electromagnetic valve 201 and the flow control module 3;
specifically, before the first standard gas is sampled, the sample valve module 2 enters a first standard gas purging mode, the two-position three-way electromagnetic valve 201, the two-position three-way electromagnetic valve 203, the three-position five-way electromagnetic valve 204 and the three-position five-way electromagnetic valve 205 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 205 are communicated with the second standard gas and purge gas, two output ports of the three-position five-way electromagnetic valve 204 are communicated with the fourth standard gas and the purge gas, the output ports of the two-position three-way electromagnetic valve 201 are communicated with the purge gas, namely the first standard gas is blocked by the three-position five-way electromagnetic valve 205, the second standard gas is blocked by the two-position three-way electromagnetic valve 201, the third standard gas is blocked by the three-position five-way electromagnetic valve 204, and the fourth standard gas is blocked by the two-position three-way electromagnetic valve 203, so that the purge gas purges all the pipelines in the sample valve module 2 through which the first standard gas needs to pass;
after the purging of the standard gas-pipeline is completed, the sample injection valve module 2 enters a standard gas-sample injection mode, the three-position five-way electromagnetic valve 204 and the three-position five-way electromagnetic valve 205 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 205 are communicated with the standard gas-and purge gas, the two output ports of the three-position five-way electromagnetic valve 204 are disconnected with the three input ports, the output ports of the two-position three-way electromagnetic valve 201 are communicated with the standard gas, the two-position three-way electromagnetic valve 203 is disconnected with the purge gas, namely, the standard gas-two is blocked by the three-position five-way electromagnetic valve 205, the purge gas is blocked by the two-position three-way electromagnetic valve 201, the standard gas-four and the other purge gas-way is blocked by the three-position five-way electromagnetic valve 204, and the standard gas-one enters the flow control module 3.
After the sample injection of the standard gas I is completed, the sample injection valve module 2 enters a standard gas two-purging mode, the two-position three-way electromagnetic valve 201 and the three-position five-way electromagnetic valve 204 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 205 are communicated with the standard gas I and purge gas, two output ports of the three-position five-way electromagnetic valve 204 are communicated with standard gas IV and purge gas, an output port of the two-position three-way electromagnetic valve 201 is communicated with purge gas, namely, the standard gas I is blocked by the two-position three-way electromagnetic valve 201, the standard gas II is blocked by the three-position five-way electromagnetic valve 205, the standard gas IV is blocked by the two-position three-way electromagnetic valve 203, and purge gas purging all the pipelines in the sample injection valve module 2 through which the standard gas II needs to pass;
after the purging of the standard gas two pipeline is completed, the sample injection valve module 2 enters a standard gas two sample injection mode, the three-position five-way electromagnetic valve 204 and the three-position five-way electromagnetic valve 205 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 205 are communicated with the standard gas two and purge gas, two output ports of the three-position five-way electromagnetic valve 204 are disconnected with the three input ports, an output port of the two-position three-way electromagnetic valve 201 is communicated with the standard gas two, the two-position three-way electromagnetic valve 203 is disconnected with purge gas, namely, the standard gas one is blocked by the three-position five-way electromagnetic valve 205, the purge gas is blocked by the two-position three-way electromagnetic valve 201, the standard gas four and the other purge gas are blocked by the three-position five-way electromagnetic valve 204, and the standard gas two enters the flow control module 3.
After the second standard gas sample injection is completed, the sample injection valve module 2 enters a standard gas three-purging mode, the two-position three-way electromagnetic valve 201 and the three-position five-way electromagnetic valve 204 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 205 are communicated with the second standard gas and purge gas, two output ports of the three-position five-way electromagnetic valve 204 are communicated with the fourth standard gas and the purge gas, the output ports of the two-position three-way electromagnetic valve 201 are communicated with the purge gas, namely, the first standard gas is blocked by the three-position five-way electromagnetic valve 205, the second standard gas is blocked by the two-position three-way electromagnetic valve 201, the third standard gas is blocked by the three-position five-way electromagnetic valve 204, and the fourth standard gas is blocked by the two-position three-way electromagnetic valve 203, and purge gas purges all the pipelines in the sample injection valve module 2 through which the third standard gas is required to pass;
after the purging of the standard gas three-pipeline is completed, the sample valve module 2 enters a standard gas three-sample-injection mode, the three-position five-way electromagnetic valve 204 and the three-position five-way electromagnetic valve 205 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 204 are communicated with the standard gas three and purge gas, two output ports of the three-position five-way electromagnetic valve 205 are disconnected with the three input ports, the output ports of the two-position three-way electromagnetic valve 201 are disconnected with the purge gas, the two-position three-way electromagnetic valve 203 is communicated with the standard gas three, namely the standard gas one, the standard gas two and the purge gas are blocked by the three-position five-way electromagnetic valve 205, the other purge gas is blocked by the two-position three-way electromagnetic valve 203, the standard gas four is blocked by the three-position five-way electromagnetic valve 204, and the standard gas three enters the flow control module 3.
After the standard gas three-injection is completed, the injection valve module 2 enters a standard gas four-purging mode, the two-position three-way electromagnetic valve 202 and the three-position five-way electromagnetic valve 203 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 205 are communicated with standard gas two and purge gas, two output ports of the three-position five-way electromagnetic valve 204 are communicated with standard gas three and purge gas, an output port of the two-position three-way electromagnetic valve 201 is communicated with purge gas, namely, the standard gas one is blocked by the three-position five-way electromagnetic valve 205, the standard gas two is blocked by the two-position three-way electromagnetic valve 201, the standard gas three is blocked by the three-position five-way electromagnetic valve 204, and purge gas purges all pipelines in the injection valve module 2 through which the standard gas four needs to pass;
after the standard gas four-pipeline purging is completed, the sample valve module 2 enters a standard gas four-sample mode, the three-position five-way electromagnetic valve 204 and the three-position five-way electromagnetic valve 205 switch internal flow paths, so that two output ports of the three-position five-way electromagnetic valve 204 are communicated with standard gas four and purge gas, two output ports of the three-position five-way electromagnetic valve 205 are disconnected with the three input ports, an output port of the two-position three-way electromagnetic valve 201 is disconnected with the purge gas, the two-position three-way electromagnetic valve 203 is communicated with the standard gas four, namely, the standard gas one, the standard gas two and the purge gas are blocked by the three-position five-way electromagnetic valve 205, the other path of purge gas is blocked by the two-position three-way electromagnetic valve 203, the standard gas four is blocked by the three-position five-way electromagnetic valve 204, and the standard gas four enters the flow control module 3.
In particular, the sample injection valve module 2 provided by the invention can be a valve group formed by a plurality of battery valves, is convenient to use and high in expansibility, and can be applied to sample injection of various standard gases without residues and pollution.
As shown in fig. 6 and 7, the present invention also provides a gas distribution method of a high-precision intelligent dynamic gas distribution system based on using a pressure sensor as a standard gas detection element 22 and a dilution gas detection element 26 and using an electromagnetic proportional valve as a standard gas execution element 21 and a dilution gas execution element 27, comprising the following steps:
s1: after the dynamic air distribution system is started, communication and air tightness check are automatically executed, and the standard air flow control assembly 4 and the dilution air flow control assembly 5 on the flow control module 3 are automatically and sequentially calibrated according to the following steps as shown in a sixth diagram:
a1, installing a flow calibration device 12, and connecting a calibration gas output port 10 and a calibration circuit interface;
a2, the sample injection valve module 2 controls standard gas to enter the standard gas flow control assembly 4 on the flow control module 3, the dilution gas flow control assembly 5 closes flow output, the output valve module 9 closes other output gas interfaces, and the output gas interfaces are communicated with the calibration gas output port 10;
a3, setting 0% opening amount of an electromagnetic proportional valve of the standard air flow control assembly 4, and measuring the output flow of the calibration air output port 10 by the flow calibration equipment 12;
a4, if the output flow is not stable for a certain time, judging that self-calibration fails, and outputting the opening degree of the proportional valve and the actual test flow;
a5, if the output flow is stable, the flow calibration equipment 12 uploads the detected flow to the MCU on the circuit control module 7;
a6, the MCU records the output flow, transmits an adjusting signal to a flow control PCB 24 on the flow control module 3, adjusts the opening amount of the proportional valve according to a certain interval by the standard gas executing element, and measures the output flow of the next calibration point;
a7, the MCU records the flow of all calibration points within the opening range of 0-99% of the proportional valve, and draws a calibration curve;
a8, the standard air flow control assembly 4 completes calibration.
a9, closing the flow output of the standard air flow control assembly 4, and calibrating the dilution air flow control assembly according to the steps a3-a 8;
s2: according to the test method, a test sequence and an automatic maintenance period are set on a display operation module 8, each row of sequence is provided with a standard gas type, a standard gas concentration, an output gas total flow, an output gas concentration and an output port type, the execution times are transmitted to a circuit control module 7, and an MCU on the circuit control module 7 automatically calculates the standard gas flow and the dilution gas flow according to a formula I according to set parameters;
equation one: mixture gas concentration=target gas flow X target gas concentration/(target gas flow+dilution gas flow)
S3: after the self-checking of the dynamic air distribution system is finished, the circuit control module 7 controls the sample injection valve module 2 to enter a purging mode, purges the internal pipeline of the dynamic air distribution system, and after the self-cleaning operation is finished, the sample injection valve module 2 is switched to a sample injection mode;
s4: MCU on the circuit control module 7 transmits control signal to flow control PCB 24, and flow control PCB 24 controls standard gas control subassembly 4 and dilution gas control subassembly 5, adjusts the flow of standard gas and dilution gas to the setting value according to closed-loop flow control, exports the gas mixing unit respectively, and the concrete realization mode is:
b1, MCU on the circuit control module 7 receives the set flow value and converts the flow value into a theoretical pressure value according to the built-in program;
b2, opening an electromagnetic proportional valve and outputting gas, and detecting the actual pressure value of the front end of the air resistor by a pressure sensor and uploading the actual pressure value to an MCU on a circuit control module 7;
b3, the MCU judges whether the difference value between the theoretical pressure value and the actual pressure value is smaller than a threshold value;
if the difference value is smaller than the threshold value, the electromagnetic proportional valve maintains the state, and the pressure sensor continuously monitors the pressure of the front end of the air resistor until the air distribution is finished;
b5, if the difference value is larger than the threshold value, the electromagnetic proportional valve adjusts the opening amount of the electromagnetic proportional valve according to the difference value, so that the difference value between the theoretical pressure value and the actual pressure value is smaller than the threshold value;
and B6, if the electromagnetic proportional valve is continuously adjusted for 5s-60s and the difference value is not smaller than the threshold value, judging the instrument to be faulty and prompting an alarm.
S5: the mixed gas is output to an output valve module 9, and the output valve module 9 controls the switch of the electromagnetic valve according to the set output port to enable the mixed gas to be output from the set output port;
s6: after the air distribution is finished, the instrument automatically enters a standby mode, and then the test and maintenance operations are executed regularly according to the set test sequence and the automatic maintenance period.
The invention designs a high-precision intelligent dynamic gas distribution system and a gas distribution method thereof, which can improve the control precision of standard gas and dilution gas flow, reduce the residue of an internal pipeline of the dynamic gas distribution system and reduce the drift influence caused by long-term operation of the dynamic gas distribution system, thereby improving the calibration accuracy of an analysis instrument. The invention adopts the electromagnetic proportional valve, the pressure sensor and the air resistor to carry out closed-loop control on the gas flow, and can greatly improve the detection precision of small-flow gas by using the pressure as the flow detection parameter. The detection precision of the pressure sensor is higher than that of the traditional mass flow sensor; according to the invention, an automatic purging and cleaning method is adopted, so that all pipelines of a dynamic gas distribution system can be purged and cleaned before each sample injection while multiple standard gases are used, cross contamination of samples is avoided, and accuracy is improved; the invention adopts the automatic calibration method of the flow control module, and can effectively avoid the drift problem of the flow control module caused by long-term operation.
The above-described embodiment is only a preferred embodiment of the present invention, and is not limited in any way, and other variations and modifications may be made without departing from the technical aspects set forth in the claims.
Claims (10)
1. The high-precision intelligent dynamic gas distribution system is characterized by comprising a sample injection valve module, a flow control module, a gas mixing module, an output valve module, a circuit control module, a case and a display operation module, wherein at least 3 gas input ports and 2 gas output ports are arranged on the surface of the case; the gas input port is respectively connected with standard gas, purge gas and diluent gas; the gas outlets are respectively connected with different detection devices;
the sample injection valve module is provided with at least two paths of input flow paths and 1 path of output flow paths, and the input flow paths are provided with electromagnetic valves for switching different input flow paths and controlling different standard gases or purge gases to enter the inside of the instrument; the output flow path is provided with a pressure sensor for measuring the pressure of the input gas;
the flow control module is provided with at least 2 flow control components, at least 1 flow control component is connected with the sample injection valve module and the gas mixing module and used for controlling the input flow of standard gas, and at least 1 flow control component is connected with the dilution gas and the gas mixing module and used for controlling the input flow of dilution gas;
the flow control assembly is used for forming closed-loop control on the flow of the gas by the MCU, the detection module and the execution module;
the gas mixing module is provided with at least two gas input ports for communicating with a flow control assembly on the flow control module;
the detection module is used for detecting the gas flow, feeding back a detection signal to the MCU, processing the detection signal into a flow signal by the MCU, feeding back an adjustment signal to the execution module, and adjusting the output flow of the pipeline according to the signal;
the output valve module is provided with 1 path of input flow path and at least 2 paths of output flow path, the input flow path is provided with a detection element for detecting total flow of output gas, and the output flow paths are provided with electromagnetic valves for controlling the output gas to enter the set detection equipment.
2. The high-precision intelligent dynamic air distribution system according to claim 1, wherein the electromagnetic valve of the sample injection valve module is at least 1 two-position three-way electromagnetic valve or two-position five-way electromagnetic valve or three-position five-way electromagnetic valve, and at least 1 two-position three-way electromagnetic valve or two-position five-way electromagnetic valve or three-position five-way electromagnetic valve is a combination.
3. The high-precision intelligent dynamic gas distribution system according to claim 1, wherein the execution module is an electromagnetic proportional valve, and the detection module comprises: pressure sensor and air resistance.
4. A high-precision intelligent dynamic air distribution system according to claim 3, wherein the air resistance is a back pressure element for forming stable air resistance, and the back pressure element is ruby air resistance or small-caliber stainless steel pipeline or capillary column.
5. A gas distribution method of the high-precision intelligent dynamic gas distribution system as claimed in any one of claims 1 to 4, comprising the following steps:
s1: after the dynamic air distribution system is started, communication and air tightness check are automatically executed, and the flow control module is automatically calibrated;
s2: according to the test method, setting a test sequence and an automatic maintenance period, wherein each row of sequence is provided with a standard gas type, a standard gas concentration, an output gas total flow, an output gas concentration and an output port type, and the execution times are counted, and the MCU automatically calculates the standard gas flow and the dilution gas flow according to set parameters;
s3: after the self-checking is finished, the sample injection valve module enters a purging mode, and after the self-cleaning operation is finished, the sample injection valve module is switched to a sample injection mode;
s4: the flow control module adjusts the flow of the standard gas and the flow of the diluent gas to set values and outputs the set values to the gas mixing module respectively;
s5: the gas is mixed and then output to the output valve module, and the output valve module controls the switch of the electromagnetic valve according to the set output port to enable the mixed gas to be output from the set output port.
6. The gas distribution method of the high-precision intelligent dynamic gas distribution system according to claim 5, wherein the automatic calibration method of the flow control module in the step S1 comprises the following steps:
a1, the output valve module closes other output ports and opens a calibration output flow path;
a2, setting 0% opening amount of the electromagnetic proportional valve, and measuring output flow;
a3, if the output flow is not stable for a certain time, judging that self-calibration fails, and outputting the opening degree of the proportional valve and the actual test flow;
a4, if the output flow is stable, the flow calibration equipment uploads the detected flow to the MCU;
a5, the MCU records the output flow, sends out a proportional valve adjusting signal, adjusts the opening amount of the proportional valve at certain intervals, and measures the output flow of the next calibration point;
a6, the MCU records the flow of all calibration points within the opening range of 0-99% of the proportional valve, and draws a calibration curve;
and a7, the flow control module completes calibration.
7. The gas distribution method of the high-precision intelligent dynamic gas distribution system according to claim 5, wherein the automatic calculation flow of the standard gas flow and the dilution gas flow in the step S2 is as follows:
a1, the MCU receives the set standard gas concentration, the total output gas flow and the output gas concentration;
a2, MCU according to the formula: the mixture gas concentration=target gas flow X target gas concentration/(target gas flow+diluent gas flow) the target gas flow and the diluent gas flow are automatically calculated.
8. The method for gas distribution in a high-precision intelligent dynamic gas distribution system according to claim 5, wherein the sample valve module in step S3 switches the purge mode and the sample mode by a two-position three-way electromagnetic valve.
9. The gas distribution method of the high-precision intelligent dynamic gas distribution system according to claim 5, wherein the specific steps of the step S3 are as follows:
b1, the MCU sends a valve cutting signal to a two-position three-way electromagnetic valve, and the sample injection valve module enters a purging mode;
b2, blocking the standard gas by a two-position three-way electromagnetic valve, and enabling the purge gas to sequentially pass through the two-position three-way electromagnetic valve, the flow control module, the gas mixing module and the output valve module to finish self-cleaning operation;
b3, after self-cleaning is finished, the MCU sends a valve cutting signal to the two-position three-way electromagnetic valve, and the sample injection valve is switched to a sample injection mode;
and B4, blocking the purge gas by a two-position three-way electromagnetic valve, sequentially passing through the two-position three-way electromagnetic valve and the flow control module, mixing the standard gas with the diluent gas in the gas mixing module, and outputting the mixed gas to the output valve module to finish the sample injection operation.
10. The gas distribution method of the high-precision intelligent dynamic gas distribution system according to claim 5, wherein the flow control module in the step S4 adjusts the flow of the standard gas and the diluent gas by adopting a closed-loop flow control mode based on a pressure sensor, and the specific implementation mode is as follows:
c1, starting air distribution by an instrument, receiving a set flow value by an MCU, and converting the flow value into a theoretical pressure value according to a built-in program;
c2, opening an electromagnetic proportional valve and outputting gas, and detecting an actual pressure value of the front end of the air resistor by a pressure sensor and uploading the actual pressure value to the MCU;
c3, the MCU judges whether the difference value between the theoretical pressure value and the actual pressure value is smaller than a threshold value;
if the difference value is smaller than the threshold value, the electromagnetic proportional valve maintains the state, and the pressure sensor continuously monitors the pressure of the front end of the air resistor until the air distribution is finished;
if the difference value is larger than the threshold value, the electromagnetic proportional valve adjusts the opening amount of the electromagnetic proportional valve according to the difference value, so that the difference value between the theoretical pressure value and the actual pressure value is smaller than the threshold value;
and C6, if the electromagnetic proportional valve is continuously adjusted for 5s-60s and the difference value is not smaller than the threshold value, judging the instrument to be faulty and prompting an alarm.
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| CN116990446A (en) * | 2023-06-14 | 2023-11-03 | 常州泰翔自动化设备科技有限公司 | Multi-gas automatic calibration detection equipment and detection method for mining portable instrument |
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| CN116990446A (en) * | 2023-06-14 | 2023-11-03 | 常州泰翔自动化设备科技有限公司 | Multi-gas automatic calibration detection equipment and detection method for mining portable instrument |
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