Intelligent switching water sample pretreatment system and method

Abstract

The application discloses a kind of intelligent switching water sample pretreatment system and method, system includes: combined sand filter sample barrel, for collecting water sample to be pretreated, initial water sample turbidity value acquisition is carried out, while water sample preliminary pre-filtering treatment is carried out;Positioning floating sampling device, for fixing to take supernatant after water sample settlement;Microfiltration module, for the microfiltration of ultrahigh turbidity water sample;Sample water transfer pump, for transmitting supernatant in combined sand filter sample barrel to microfiltration module;Sample collection barrel, for collecting and detecting water sample quantity after processing, for instrument or laboratory personnel to sample analysis;Valve assembly, by valve opening and closing, water sample is switched different pretreatment mode;Cleaning assembly, including rotary high-pressure spray head and self-heating ultrasonic cleaning device, for cleaning system after pretreatment internal residual adherend.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental water ecological monitoring, and in particular to a water sample pretreatment system and method with intelligent switching. BACKGROUND

[0002] China is a high-speed developing country, and the water quality of rivers is diverse. Different rivers and seasons have different monitoring interference substances in the water body, which greatly affect the accuracy of automatic monitoring data. The country has been promoting the establishment of a surface water environmental quality monitoring system mainly based on automatic monitoring and supplemented by manual monitoring. However, during monitoring, the change of interference substances in the water quality of rivers at different times is crucial to the accuracy of monitoring data. SUMMARY

[0003] To solve the above problems, the present application provides a water sample pretreatment turbidity reduction system and method with intelligent switching, which can automatically identify the change of interference substances in the measured water and switch the water sample pretreatment process.

[0004] To achieve the above purpose, the present application adopts the following scheme:

[0005] A water sample pretreatment system with intelligent switching, comprising:

[0006] A combined sand and filter sampling bucket for collecting water samples to be pretreated, collecting initial water sample turbidity values and performing primary water sample pretreatment;

[0007] A micropore filter module for micropore filtration of water samples with ultra-high turbidity;

[0008] A sample water transfer pump for transferring supernatant in the combined sand and filter sampling bucket to the micropore filter module;

[0009] A sample collection bucket comprising a stainless steel bucket and a high and low liquid level detection device for collecting and detecting treated water samples for sampling analysis by instruments or laboratory personnel;

[0010] A valve assembly for switching different pretreatment modes by opening and closing the valve to transport water samples;

[0011] A cleaning assembly for cleaning residual attachments inside the system after pretreatment;

[0012] An intelligent control module for automatically controlling the switching of different pretreatment processes through initial water sample interference substance detection to complete water sample pretreatment

[0013] Preferably, the combined sand filtration sampling barrel comprises a barrel-shaped box made of stainless steel, a stainless steel filter screen is vertically arranged in the middle of the barrel-shaped box, the barrel is divided into left and right two areas, the original water enters the left area of the barrel, is preliminarily pretreated by the stainless steel filter screen, and then enters the right area, a positioning floating sampling device is arranged in the right area and is used for taking supernatant of the water sample after sedimentation, the positioning floating sampling device is composed of a buoyancy device and a connecting hose, one end of the connecting hose is connected to the buoyancy device, and the other end is connected to a sampling outlet of the right area of the combined sand filtration sampling barrel, and the buoyancy device descends with the liquid surface to ensure that the water sample taken from the sampling outlet is the supernatant of the right area of the combined sand filtration sampling barrel.

[0014] Preferably, the barrel-shaped box made of stainless steel is made of 316 stainless steel, and the stainless steel filter screen is a replaceable stainless steel filter screen with a pore size of 63 μm.

[0015] Preferably, the micro-porous filtration module is composed of a micro-porous filter and a shell cover, sample water can enter the shell cover through a pipeline, and the sample water is pretreated by the micro-porous filter through a natural permeation or pressurized filtration mode, and the pretreated sample water flows out from a water outlet hole at the bottom of the micro-porous filter.

[0016] Preferably, the micro-porous filter is a sintered 5 μm or 10 μm or 20 μm micro-porous filter core made of stainless steel or titanium alloy.

[0017] Preferably, the cleaning assembly comprises a rotary high-pressure spray head, a self-heating ultrasonic cleaning rod and a high-pressure air compressor, the rotary high-pressure spray head is arranged in the combined sand filtration sampling barrel, and the self-heating ultrasonic cleaning rod is arranged in the micro-porous filtration module, which is used for cleaning the combined sand filtration sampling barrel, the micro-porous filtration module, the sampling barrel, the transfer pump and the pipeline after pretreatment of the system, so as to prevent the system from being blocked and reduce the pretreatment capacity.

[0018] Preferably, the intelligent control module comprises a turbidity detector, a PLC controller, a visual operation module and an industrial computer, the PLC controller automatically switches different pretreatment processes according to the turbidity of the water sample detected by the turbidity detector, the process condition and the pretreatment progress are clearly observed through the visual operation module, and the intelligent switching of the water sample pretreatment is realized.

[0019] Preferably, the water sample pretreatment system with intelligent switching further comprises a cleaning assembly for cleaning the residues attached in the system after pretreatment.

[0020] A method for applying the above-mentioned water sample pretreatment system with intelligent switching, comprising the following steps:

[0021] (1) sample water inlet, introducing the sample to be measured into the combined sand filtration sampling barrel, and preliminarily pretreating the sample in the sampling barrel; the original water sample is filtered by the stainless steel filter screen to remove the particulate matters in the water, and then is naturally settled for a certain time to obtain supernatant for next process pretreatment;

[0022] 2. Turbidity detection and judgment, the intelligent control module detects the turbidity value of the combined sand filtration sampling barrel, and automatically switches the relative contrast level pretreatment process;

[0023] 6. Water sample pretreatment, according to the intelligent control module, switch different pretreatment processes for pretreatment, specifically divided into low turbidity, medium turbidity, high turbidity three pretreatment processes;

[0024] Low turbidity water sample pretreatment, after the combined sand filtration sampling barrel is naturally settled by valve switching, through high differential design, the supernatant in the barrel automatically flows into the sampling barrel, and after the sampling barrel detects enough sample amount through the liquid level detection device, the relevant valve is closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling test can be carried out;

[0025] Medium turbidity water sample pretreatment, after the combined sand filtration sampling barrel is naturally settled by valve switching, through high differential design, the supernatant sample in the combined sand filtration sampling barrel flows into the sampling barrel through the natural permeation of the microporous filtration module, and after the sampling barrel detects enough sample amount through the liquid level device, the relevant valve is closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling test can be carried out;

[0026] High turbidity water sample pretreatment, after the combined sand filtration sampling barrel is naturally settled by valve switching, through high differential design, the supernatant sample in the combined sand filtration sampling barrel flows into a part of the sample into the sampling barrel, so that a layer of filter membrane is formed on the surface of the microporous filtration module. Then, the supernatant in the combined sand filtration sampling barrel is pumped by the sample water transfer pump and is pressurized into the microporous filtration module for filtration in pressure filtration mode. After the sampling barrel detects enough sample amount through the liquid level device, the relevant valve is closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling test can be carried out;

[0027] 7. Sample water test, after detecting enough liquid amount in the sampling barrel, instrument or manual sampling measurement is carried out;

[0028] ⑸System cleaning, during the sample water test, the system synchronously carries out internal pipeline cleaning, including: combined sand filter sampling barrel cleaning, the inside wall and stainless steel filter screen in the barrel are fully flushed by high-pressure tap water through a rotary high-pressure nozzle, and the cleaning liquid is discharged through a valve; micro-porous filter module cleaning, the inside-out flushing of the filter core in the micro-porous filter module is carried out for a certain time by high-pressure tap water through a valve switching, the self-heating ultrasonic cleaning device is started to carry out ultrasonic vibration cleaning on the filter core to completely remove the blockage in the filter core gap; pipeline valve cleaning, tap water is used to flush all pipeline valves, waste liquid is discharged, and finally the whole is blown by high-pressure compressed air to ensure that the micro-porous filter module, the combined sand filter sampling barrel, the sample receiving barrel and the pipeline valve are free of residues, and preparation is made for the next pretreatment.

[0029] Preferably, in step ⑸ of the above method, the pipeline valve cleaning is carried out by connecting an ozone generating device to automatically generate ozone and water gas mixing device, mixing with tap water to flush all pipeline valves.

[0030] The present application realizes intelligent identification of water sample turbidity interference changes, automatic switching to reasonable water sample pretreatment process, thereby solving the problem that the water quality interference is variable, the pretreated water sample cannot meet the detection requirements of the analyzer, solving the influence of the variable interference substances in the measured water body on the measurement data accuracy of the monitoring instrument, improving the efficiency and recognition of automatic monitoring data, greatly improving the adaptability of the system and ensuring the accuracy and efficiency of water quality data measurement. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The figure shows the overall flowchart of the embodiment of the present application;

[0032] Figure 2 The figure shows the structure schematic diagram of the combined sand filter sampling barrel of the embodiment of the present application;

[0033] Figure 3 The figure shows the side view of Figure 2 ;

[0034] Figure 4 The figure shows the structure schematic diagram of the micro-porous filter module of the embodiment of the present application;

[0035] Figure 5 The figure shows the structure schematic diagram of the sample receiving barrel of the embodiment of the present application;

[0036] Figure 6 The figure is a flowchart of the method running steps of the water sample pretreatment system using the above intelligent switching

[0037] Among them:

[0038] 100 combination type sand setting and filtering sampling barrel; 101 replaceable stainless steel filtering screen; 102 positioning floating sampling device; 103 rotary high pressure spray head; 104 liquid level monitoring device; 105 high liquid level detection device of sampling barrel; 106 low liquid level detection device of sampling barrel; 107 sampling barrel; 108, 109 instrument measuring sampling cup; 110 self-heating type ultrasonic cleaning device and the like;

[0039] 200 turbidity detector; 201 micro-porous filtering module; 202 bypass membrane filtering module;

[0040] 300 cleaning assembly device.

[0041] 400, 401 combination type sand setting and filtering sampling barrel drainage ball valve; 405 sample water transfer pump; 402, 403, 404, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415 each pretreatment switching valve assembly.

[0042] 500 intelligent control module; DETAILED DESCRIPTION

[0043] In order to better understand the technical solutions of the present application, the following will combine the accompanying drawings to further describe the present application. Figure 1 The present application is further described.

[0044] As shown in Figure 1 , an intelligent switching water sample pretreatment system comprises:

[0045] The combination type sand setting and filtering sampling barrel 100 is used for collecting water samples to be pretreated, collecting initial water sample turbidity values and performing primary water sample pretreatment filtering; as shown in Figure 2 , Figure 3 The combination type sand setting and filtering sampling barrel 100 comprises a 316 stainless steel barrel-shaped box 11, a 63 μm replaceable stainless steel filtering screen 101 is vertically arranged in the middle of the barrel-shaped box, which divides the barrel into left and right two areas 12, 13, raw water enters the left area 12 from the barrel, passes through the stainless steel filtering screen 101 to perform primary pretreatment filtering into the right area 13, the positioning floating sampling device 102 is arranged in the right area 13 for sampling supernatant 14 after sedimentation, the positioning floating sampling device 102 is composed of a buoyancy device 15 and a connecting hose 16, one end of the connecting hose 16 is connected to the buoyancy device 15, and the other end is connected to a sampling outlet 17 of the right area of the combination type sand setting and filtering sampling barrel, the buoyancy device 15 descends with the liquid level to ensure that the sample water discharged from the sampling outlet 17 is the supernatant of the right area of the combination type sand setting and filtering sampling barrel.

[0046] Microfiltration module 201 is used for microfiltration of ultra-high turbidity water sample, as shown in 4, which is composed of microfiltration filter 21 and shell cover 22. The microfiltration filter 21 is preferably made of stainless steel or titanium alloy sintering to form different microfiltration filter elements. The filter elements are preferably 5 μm, 10 μm, 20 μm, etc. The actual sample water quality can be selected according to the actual sample water quality. The self-heating ultrasonic cleaning rod 110 is also provided inside. The shell cover 22 is a 316 stainless steel circular cavity.

[0047] Sample water delivery pump 405 adopts a high-pressure diaphragm pump with high outlet pressure and good passability. When the turbidity of the water sample is high, the sample water cannot be pretreated by natural permeation into the microfiltration module. At this time, the sample water delivery pump 405 transmits the supernatant in the combined sand filtration sampling barrel 100 to the microfiltration module 201 for pretreatment by pressurization;

[0048] The sample collection barrel 107, as shown in Figure 5 , is made of 316 stainless steel and welded into an open-top square barrel. The high liquid level detection device 105 and the low liquid level detection device 106 are installed on the barrel to collect and detect the amount of treated water sample for sampling analysis by the instrument or laboratory personnel.

[0049] Valve assemblies 402, 403, 404, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415 switch different pretreatment modes by opening and closing the valves.

[0050] The cleaning assembly 300 is used for cleaning the combined sand filtering sampling barrel, the micro-porous filtering module, the sampling barrel, the delivery pump and the pipeline after the system pretreatment, preventing the system from being blocked and reducing the pretreatment capacity, and comprising a rotary high-pressure spray head 103, a self-heating ultrasonic cleaning rod 110, an ozone generating device, a water-gas mixing device, a high-pressure air compressor and a cleaning valve. The rotary high-pressure spray head 103 is arranged in the combined sand filtering sampling barrel, and a light plastic rotary high-pressure spray head 103 is adopted, which requires small starting rotary water pressure and has good cleaning effect, and is used for cleaning the side wall of the combined sand filtering sampling barrel and the replaceable stainless steel filter screen 101. The self-heating ultrasonic cleaning rod 110 is preferably a circular ultrasonic vibration rod, which is arranged in the micro-porous filter of the micro-porous filtering module 201. The cleaning water is heated to 40-45 DEG C, and then the impurities and attachments on the micro-porous filter are removed through ultrasonic vibration. The ozone generating device, the water-gas mixing device and the high-pressure air compressor are located in the cleaning device, and are mainly used for the following steps after the above cleaning steps are completed. The ozone generated by the ozone generating device is mixed with the water-gas mixing device, mixed with tap water through the water-gas mixing device, and then flushed to all pipeline valves, and the waste liquid is discharged. Finally, the whole is blown and washed by high-pressure compressed air, so that the micro-porous filtering module, the combined sand filtering sampling barrel, the sampling barrel, the pipeline valve and other microorganisms in the pipeline are free of residues, and the problem of breeding of microorganisms in the pipeline is prevented, so as to prepare for the next pretreatment.

[0051] The intelligent control module 500 comprises a turbidity detector, a PLC controller, a visual operation module and an industrial computer. According to the turbidity of the water sample detected by the turbidity detector, the PLC controller automatically switches different pretreatment processes, the process condition and the pretreatment progress are clearly observed through the visual operation module, and the intelligent switching of the water sample pretreatment is realized.

[0052] Figure 6 The embodiment of the intelligent switching water sample pretreatment method is shown in the summary diagram of the operation steps. The turbidity value of the measured sample water can be intelligently detected, the appropriate water sample pretreatment process is automatically switched according to the comparison between the value and the threshold value, the interference of the turbidity in the raw water sample on the measurement of the instrument or the laboratory personnel is reduced, and the accuracy of the measurement of the water sample pollution factor by the instrument or the laboratory personnel is improved. Figure 2 The operation steps of the present application are further described in detail, including:

[0053] (1) Sample water inlet: introducing the measured sample into the combined sand filtering sampling barrel, and performing initial pretreatment in the sampling barrel. The raw water sample is filtered through the 63 mu stainless steel filter screen to remove the particulate matter in the water, and then naturally settles for a certain time to obtain the supernatant for the next process pretreatment.

[0054] (2) Turbidity detection and judgment: detecting the turbidity value of the water sample in the combined sand filtering sampling barrel by the intelligent control module, and automatically switching the relative comparison level pretreatment process.

[0055] ⑥Water sample pretreatment, according to the intelligent control module, switch different pretreatment process for pretreatment, specifically divided into low turbidity, turbidity, high turbidity three pretreatment process;

[0056] When the water sample is low turbidity, the valve switches after the combined sand filter sampling barrel is naturally settled. Through the high differential design, the supernatant in the barrel automatically flows into the sampling barrel. When the sampling barrel detects enough sample amount through the liquid level device, the relevant valve is closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling test can be carried out.

[0057] When the water sample is turbidity, the valve switches after the combined sand filter sampling barrel is naturally settled. Through the high differential design, the supernatant sample in the combined sand filter sampling barrel flows into the sampling barrel through the natural permeation of the microporous filter module. When the sampling barrel detects enough sample amount through the liquid level device, the relevant valve is closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling test can be carried out.

[0058] When the water sample is high turbidity, the valve switches after the combined sand filter sampling barrel is naturally settled. Through the high differential design, the supernatant sample in the combined sand filter sampling barrel flows into the sampling barrel through the natural permeation of the microporous filter module. When the sampling barrel detects enough sample amount through the liquid level device, the relevant valve is closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling test can be carried out.

[0059] ⑥Sample water test: After detecting enough liquid in the sampling barrel, the instrument or manual sampling measurement is carried out.

[0060] ⑸System cleaning: During the sample water test, the system synchronously cleans the internal pipeline, including the cleaning of the combined sand filter sampling barrel, the cleaning of the microporous filter module, and the cleaning of the pipeline valve.

[0061] (6) Complete, complete sample water pretreatment and test.

[0062] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or variations made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. An intelligent switching water sample pre-treatment system, characterized in that: The system comprises a combined sand filtration sampling bucket for collecting water samples to be pretreated, collecting initial water sample turbidity values and performing primary water sample pre-filtering; a microporous filtration module for microporous filtration of water samples with ultra-high turbidity; a sample water transfer pump for transferring supernatant in the combined sand filtration sampling bucket to the microporous filtration module; a sample collection bucket comprising a stainless steel bucket and a high-low liquid level detection device for collecting and detecting treated water samples for instrument or laboratory personnel to take samples for analysis; a valve assembly for switching different pretreatment modes by opening and closing the valve to deliver water samples; an intelligent control module for automatically switching different pretreatment processes through initial water sample interference detection to complete water sample pretreatment; the combined sand filtration sampling bucket comprises a stainless steel bucket-shaped box, a stainless steel filter screen is vertically arranged in the middle of the bucket-shaped box, the bucket is divided into left and right two areas, raw water enters the right area after primary pretreatment and filtration through the stainless steel filter screen, a positioning floating sampling device is arranged in the right area for taking supernatant of the settled water sample, the positioning floating sampling device is composed of a buoyancy device and a connecting hose, one end of the connecting hose is connected to the buoyancy device, and the other end is connected to a sample outlet of the right area of the combined sand filtration sampling bucket, the buoyancy device descends with the liquid level to ensure that the water sample taken from the sample outlet is the supernatant of the right area of the combined sand filtration sampling bucket; the intelligent switching water sample pretreatment system further comprises a cleaning assembly for cleaning the residual attachments in the system after pretreatment, the cleaning assembly comprises a rotary high-pressure spray head, a self-heating ultrasonic cleaning rod, an ozone generating device and a high-pressure air compressor, the rotary high-pressure spray head is arranged in the combined sand filtration sampling bucket, and the self-heating ultrasonic cleaning rod is arranged in the microporous filtration module, which is used for comprehensive cleaning of the combined sand filtration sampling bucket, the microporous filtration module, the sample collection bucket, the transfer pump and the pipeline after pretreatment of the system to prevent system blockage and reduce pretreatment capacity.

2. The smart-switchable water sample pretreatment system of claim 1, wherein: The stainless steel bucket-shaped box is made of 316 stainless steel, and the stainless steel filter screen is a replaceable stainless steel filter screen with a mesh size of 63 μm.

3. The smart-switchable water sample pretreatment system of claim 1, wherein: The microporous filtration module is composed of a microporous filter and a shell cover, sample water can enter the shell cover through a pipeline, and the water sample is pretreated through the microporous filter in a natural permeation or pressurized filtration mode, and the pretreated water sample flows out from the water outlet hole at the bottom of the microporous filter.

4. The smart-switchable water sample pretreatment system of claim 3, wherein: The microporous filter is a 5 μm, 10 μm or 20 μm microporous filter element made of stainless steel or titanium alloy sintering.

5. The smart-switchable water sample pretreatment system of claim 1, wherein: The intelligent control module comprises a turbidity detector, a PLC controller, a visual operation module and an industrial computer, the PLC controller automatically switches different pretreatment processes according to the turbidity detected by the turbidity detector, the process status and pretreatment progress are clearly observed through the visual operation module, and the intelligent switching of water sample pretreatment is realized.

6. A method for applying the intelligent switching water sample pretreatment system according to any one of claims 1-5, comprising the following steps: 1) Sample water is introduced into the combined sand filtration sampling barrel, and the raw water sample is filtered through a stainless steel filter to remove particulate matter in the water. Then, after a certain period of natural sedimentation, the supernatant is obtained and enters the next process of pretreatment; 2) Turbidity detection and judgment: the intelligent control module detects the turbidity value of the water sample in the combined sand filtration sampling barrel, and automatically switches to the relative reference level pretreatment process; 3) Water sample pretreatment: according to the intelligent control module, different pretreatment processes are switched to pretreat the water sample, which is divided into low turbidity, medium turbidity, and high turbidity pretreatment processes; When the turbidity is low, the water sample is pretreated by valve switching after natural sedimentation in the combined sand filtration sampling barrel. Through high differential design, the supernatant in the barrel automatically flows into the sample collection barrel. When the sample collection barrel detects enough sample volume through the liquid level device, the relevant valves are closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling tests can be performed; When the turbidity is medium, the water sample is pretreated by valve switching after natural sedimentation in the combined sand filtration sampling barrel. Through high differential design, the supernatant sample in the combined sand filtration sampling barrel flows into the sample collection barrel through the micro-porous filtration module by natural permeation. When the sample collection barrel detects enough sample volume through the liquid level device, the relevant valves are closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling tests can be performed; When the turbidity is high, the water sample is pretreated by valve switching after natural sedimentation in the combined sand filtration sampling barrel. First, through high differential design, the supernatant sample in the combined sand filtration sampling barrel flows into a part of the sample collection barrel through the micro-porous filtration module by natural permeation, forming a layer of filter membrane on the surface of the micro-porous filtration module. Then, through the sample water transfer pump, the supernatant in the combined sand filtration sampling barrel is extracted and pressurized into the micro-porous filtration module for filtration. When the sample collection barrel detects enough sample volume through the liquid level detection device, the relevant valves are closed. At this time, the interference in the water sample meets the requirements of instrument or human testing, and relevant sampling tests can be performed; 5) Sample water testing: after detecting enough liquid volume in the sample collection barrel, the instrument or manual sampling measurement is performed; 6) System cleaning: during the sample water testing, the system simultaneously cleans the internal pipeline, including: combined sand filtration sampling barrel cleaning, high-pressure tap water is used to flush the inner wall of the barrel and the stainless steel filter through a rotating high-pressure nozzle, and the cleaning liquid is discharged through the valve; Micro-porous filtration module cleaning: through valve switching, high-pressure tap water is used to flush the inside of the filter core of the micro-porous filtration module outward for a certain period of time, and a self-heating ultrasonic cleaning device is started to clean the filter core by ultrasonic vibration, completely removing the blockage in the filter core gap; pipeline valve cleaning: tap water is used to flush all pipeline valves, waste liquid is discharged, and finally the whole is blown with high-pressure compressed air to ensure that there is no residue in the micro-porous filtration module, combined sand filtration sampling barrel, sample collection barrel, and pipeline valves, and to prevent the growth of other microorganisms in the pipeline.

7. The method of claim 6, wherein in step ⑸, the pipeline valve is washed, the ozone generator is connected to the water-gas mixing device to generate ozone automatically, the ozone is mixed with the tap water through the water-gas mixing device, and all pipeline valves are washed.

Images