CN109724849B - Automatic filter membrane replacing device and method and membrane replacing mechanism - Google Patents
Automatic filter membrane replacing device and method and membrane replacing mechanism Download PDFInfo
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- CN109724849B CN109724849B CN201910106981.0A CN201910106981A CN109724849B CN 109724849 B CN109724849 B CN 109724849B CN 201910106981 A CN201910106981 A CN 201910106981A CN 109724849 B CN109724849 B CN 109724849B
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Abstract
The invention provides an automatic filter membrane replacing device for gas component detection equipment, which comprises: a detection unit that detects a degree of contamination of a filter membrane of the gas composition detection apparatus as a detection result; and a membrane replacement unit that replaces the filtration membrane in response to a detection result of the detection unit satisfying a predetermined condition.
Description
Technical Field
The present invention relates to an automatic filter membrane replacement device, and more particularly, to an automatic filter membrane replacement device, an automatic filter membrane replacement method, and a filter membrane replacement mechanism for use in a gas component detection apparatus.
Background
In recent years, due to the importance of gas quality in a specific environment, it is necessary to measure gas components in the environment, for example, the concentration of a specific gas in a work site, and the measurement of an air sample when atmospheric pollution is studied, and the like.
Taking the latter of the above scenarios as an example, an air sample needs to be collected when monitoring atmospheric pollution. When collecting an atmospheric sample, a filter membrane is usually used to remove particles such as dust. In this case, the filter membrane needs to be replaced in time, usually at a predetermined, fixed time period. For example, chinese patent No. 201510870721.2 describes an automatic membrane replacement device which can automatically replace a filtration membrane.
However, in the above technique, the membrane can only be replaced at predetermined fixed time intervals, and the replacement timing cannot be determined based on the contamination of the filtration membrane. This may result in waste of the filter membrane due to too frequent replacement of the filter membrane or may result in inaccurate measurement results of the gas to be measured due to untimely replacement of the filter membrane.
In addition, in the conventional automatic membrane replacement apparatus, there is also a means in which a technician resets a time interval for replacing the filtration membrane according to the degree of contamination of the replaced filtration membrane.
The above technique greatly increases the workload of the worker. Moreover, since the judgment standards of the contamination degree are different among different workers, the replacement time interval is set differently, and thus, the detection data may be inaccurate.
Disclosure of Invention
The present invention has been made in view of the above problems in the prior art, and to solve the above problems.
According to a first aspect of the present invention, there is provided an automatic filter membrane replacing apparatus for a gas component detecting apparatus, comprising: a detection unit that detects a degree of contamination of a filter membrane of the gas composition detection apparatus as a detection result; and a membrane replacement unit that replaces the filtration membrane in response to a detection result of the detection unit satisfying a predetermined condition.
Preferably, the automatic filter membrane replacing device further comprises a control unit for controlling the membrane replacing unit to replace the filter membrane according to the detection result of the detection unit, wherein the control unit controls the membrane replacing unit to start replacing the filter membrane when the detection result of the detection unit meets a preset condition.
Preferably, the degree of contamination of the filter membrane is indicated in the transmittance or reflectance of the filter membrane to light.
Preferably, the transmittance of the filter membrane for light is determined by the intensity of transmitted light I detected when the filter membrane has been in use for a time ttAnd the intensity of transmitted light I detected when the filter membrane is not in use0Ratio of T betweentTo represent; and the reflectivity of the filter membrane to light is determined by the intensity of reflected light I detected when the filter membrane has been in use for a time ttIntensity of reflected light I detected when the filter membrane is not in use0Ratio R betweentTo indicate.
Preferably, the predetermined condition is one of the following conditions: (1) rtLess than a predetermined value R0(ii) a And (2) TtLess than a predetermined value T0。
Preferably, the membrane replacement unit includes a filter membrane holding structure including an upper holder, a lower holder, and a clamp provided between the upper holder and the lower holder for clamping the filter membrane, and the upper holder and the lower holder are detachably provided opposite to each other to accommodate the filter membrane and form a space as a gas passage.
Preferably, the membrane replacement unit further includes a filtering membrane replacement unit driven by a motor to replace the filtering membrane
Preferably, an air inlet, a light source interface and a detector interface are arranged on the upper holder, and an air outlet is arranged on the lower holder; or the upper holding piece is provided with an air inlet and a light source interface, and the lower holding piece is provided with an air outlet and a detector interface.
Preferably, the lower holder includes a mesh-shaped support plate provided at an upper portion of the lower holder for supporting the clamp.
Preferably, the upper and/or lower holders are movable to expose the filter membrane.
Preferably, the detection unit includes: a light source for emitting light incident on the filter membrane; and the optical detector is used for detecting and storing the intensity of the reflected light of the filter membrane.
Preferably, the control unit controls the light source to emit light at predetermined time intervals, and controls the detector to detect the intensity of the reflected light of the filter membrane at predetermined time intervals.
According to the invention, the timing of replacing the filter membrane can be accurately determined by measuring the light reflected by the filter membrane, so that the accuracy of measuring the gas component to be measured can be improved, and the waste of the filter membrane can be avoided.
An aspect of a second aspect of the present invention provides a membrane replacement mechanism for replacing a filtration membrane of a gas component detection apparatus, an upper holder and a lower holder that are provided opposite to each other in a separable manner; and a clamping member for clamping the filtration membrane and provided between the upper and lower holders, wherein a closed space is formed between the upper and lower holders, the closed space serving as a gas passage for passing a gas therethrough, and the filtration membrane clamped by the clamping member is provided between the upper and lower holders.
Preferably, an air inlet, a light source interface and a detector interface are arranged on the upper holder, and an air outlet is arranged on the lower holder, or an air inlet and a light source interface are arranged on the upper holder, and an air outlet and a detector interface are arranged on the lower holder.
Preferably, the lower holder includes a support plate having a plurality of holes, the support plate being disposed at an upper portion of the lower holder for supporting the clamping member.
Preferably, the upper and/or lower holders are movable to expose the filter membrane.
An aspect of the third aspect of the present invention provides a method for automatically replacing a filtration membrane for a gas component detection apparatus, the method comprising the steps of: a detection step, detecting the pollution degree of a filtering membrane of gas component detection equipment as a detection result; and a membrane replacement step of replacing the filtration membrane in response to a detection result of the detection unit satisfying a predetermined condition.
Preferably, the degree of contamination of the filter membrane is indicated by the light transmission or reflection of the filter membrane.
Preferably, the transmittance of the filter membrane is determined by the intensity of transmitted light I detected when the filter membrane has been in use for a time ttAnd the intensity of transmitted light I detected when the filter membrane is not in use0Ratio of T betweentTo represent; and the light reflectivity of the filter membrane is determined by the intensity of reflected light I detected when the filter membrane has been used for a time ttIntensity of reflected light I detected when the filter membrane is not in use0Ratio R betweentTo indicate.
Preferably, the predetermined condition is one of the following conditions: (1) rtLess than a predetermined value R0(ii) a And (2) TtLess than a predetermined value T0。
According to the technical scheme of the third aspect of the invention, the time for replacing the filtering membrane can be accurately judged, so that the measurement precision of the gas to be measured can be improved, and the waste of the filtering membrane can be avoided.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and it is obvious for those skilled in the art or ordinary skill in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 illustrates a functional configuration diagram of an automatic filtering membrane replacing apparatus according to the present invention.
Fig. 2 illustrates a schematic configuration of a sensing unit of the automatic filtering membrane replacing apparatus according to the first embodiment of the present invention.
Fig. 3 illustrates a schematic configuration diagram of an automatic filtering membrane replacing apparatus according to a first embodiment of the present invention.
Fig. 4 illustrates a schematic structural view of each component of the automatic filtering membrane replacing apparatus according to the first embodiment of the present invention.
FIG. 5 illustrates an example of the appearance of a filter membrane according to a first embodiment of the invention after use for various periods of time.
Fig. 6 illustrates a graph of the numerical relationship between the intensity of the reflected light and the time of use of the filter membrane according to the first embodiment of the present invention.
Fig. 7 illustrates a flow of automatically replacing the filtering membrane according to the first embodiment of the present invention.
Fig. 8 illustrates a schematic configuration diagram of an automatic filtering membrane replacing apparatus according to a third embodiment of the present invention.
Fig. 9 illustrates a flow of automatically replacing the filtering membrane according to the third embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings. It should be understood that the following embodiments are not intended to limit the present invention, and not necessarily all combinations of aspects described according to the following embodiments are required as to means for solving the problems according to the present invention. For the sake of simplicity, the same reference numerals or signs are used for the same structural parts or steps, and the description thereof is omitted.
[ first embodiment ]
[ functional Structure of automatic film changer ]
First, the filtration membrane of the present invention will be explained. The filtration membrane in the present invention is a filtration membrane for filtering a gas to be measured when the gas is detected. For example, the gas to be detected is the atmosphere and NO in the atmosphere is to be detected3The content of (b) is determined by the content of (a), the filter membrane filters aerosol, solid small particles and the like in the atmosphere. After being used for a period of time, the filter membrane is polluted, and the automatic filter membrane replacing device can automatically replace the polluted filter membrane.
The functional configuration diagram of the automatic filtration membrane replacement apparatus of the first embodiment of the present invention, which includes a detection unit 1, a membrane replacement unit 2, a control unit 3, and a storage unit 4, is described below with reference to fig. 1.
The detection unit 1 is used to detect the degree of contamination of the filtration membrane of the gas component detection apparatus as a detection result, and send the detected result to the control unit. The specific configuration of the detection unit will be described in detail below.
The film replacing unit 2 is used for responding to the detection result of the detection unit meeting a predetermined condition, and the specific construction of the film replacing unit 2 will be described in detail below.
The control unit 3 is used for controlling the detection unit 1 to detect the intensity of the reflected light and enabling the membrane replacing unit 2 to replace the filtering membrane according to the detection result of the detection unit 1.
Examples of the control unit 3 include a CPU, a personal PC, a mobile terminal, and the like integrated in the automatic filter membrane replacement device. Details about the control unit 3 will be described in detail below.
The storage unit 4 is used for storing data on the automatic film changer, including, for example: parameters relating to the filter membrane (brand, model, length of use, measurements made over time)Predetermined values R for intensity of reflected light, etc., used for different filter membranes0Etc.); parameters regarding the light source (wavelength, light intensity, etc.); and parameters (brand, model, etc.) relating to the detector that detects the reflected light, etc.
[ detection Unit ]
Next, the structure of the detection unit 1 of the automatic filtration membrane replacement apparatus will be described with reference to fig. 2. Further, the following configuration is described as an example in the present embodiment, but the detection unit of the present invention is not limited to the configuration shown in fig. 2.
The detection unit 1 includes: a light source 11 and a light detector 12. The light source 11 is used to emit light that impinges on the filter membrane at predetermined time intervals.
The light source 11 may be a light source selected from a small size, a low price, and a small amount of heat generation, and may be a laser diode, for example. When a laser diode is used, the laser diode may be directly mounted on the upper cylinder 21. The light source 11 may be LED or other light source, and the light emitted from the LED may be introduced into the space between the upper cylinder and the lower cylinder by using an optical fiber. The light emitting wavelength of the light source is selected according to the specific gas to be detected, and the principle is that the accuracy of gas detection is not affected. To detect the active free radical NO in the atmosphere at night3For example, NO3The absorption spectrum of (2) is in the range of 620-670nm, and the wavelength of the light source is selected to avoid the range when the light is decomposed by illumination.
The light source may be activated at intervals (e.g., 5 minutes) and allowed to continue to emit light for a period of time (e.g., 5 seconds). Light rays emitted by the light source are projected to the front surface of the filter membrane and reach the sensor after being reflected by the filter membrane. The time interval may also be other values, for example, it may be set to 3 minutes, 10 minutes, 30 minutes, one hour, etc., depending on the properties of the gas to be measured and the properties of the filtration membrane.
A light detector 12 for measuring the intensity of reflected light of the filter membrane at predetermined time intervals (e.g., 5 minutes) and storing the measured intensity of reflected light. The time interval may also be other values, for example, it may be set to 3 minutes, 10 minutes, 30 minutes, one hour, etc., depending on the properties of the gas to be measured and the properties of the filtration membrane.
The light detector may be, for example, a small-sized and low-priced silicon photodiode, which may be directly mounted on the upper cylinder 21. The switching of the photodiode is controlled by a computer program.
The light detector is activated at intervals (e.g. 5 minutes) and continues to detect for a period of time (e.g. 5 seconds) to measure the fraction of the light emitted by the light source that is reflected by the filter membrane and reaches the light detector.
[ film changing Unit ]
Next, the structure of the film changing unit is described with reference to fig. 3 and 4. Further, the following configuration is described as an example in the present embodiment, but the film replacing unit of the present invention is not limited to the configuration shown in fig. 3 and 4.
The membrane replacing unit 2 comprises an upper holding member, a lower holding member and a clamping member arranged between the upper holding member and the lower holding member, wherein the upper holding member and the lower holding member are detachably arranged oppositely to form a space for accommodating the filtering membrane and providing a gas channel.
In the present embodiment, the upper cylinder 21 is used as the upper holder, the lower cylinder 26 is used as the lower holder, and the filter membrane holder 25 is used as the holder. To detect NO in the atmosphere3The content is taken as an example to illustrate the specific structure of the membrane replacing unit. A sampling pipe (not shown) collects air to be tested, the collected air to be tested enters the closed space formed by the upper air cylinder 21 and the lower air cylinder 26 through the air inlet 24, the air to be tested is filtered by the filtering membrane 29 and then is sent to the detection system through the air outlet 27 to detect NO in the air to be tested3And (4) content. In addition, the membrane replacement unit 2 also comprises a membrane replacement device, not shown, for replacing the filtration membrane. After the upper air cylinder 21 is lifted, the membrane replacing device moves to take the filtering membrane to be replaced off the filtering membrane clamp, a new filtering membrane is replaced, then the membrane replacing device moves, the upper air cylinder 21 resets, and the gas to be tested in the next period is filtered continuously.
The upper and lower cylinders 21 and 26 and the filter membrane holder 25 disposed therebetween form a space that accommodates the filter membrane 29 and serves as a gas passage for the gas to be measured. The upper cylinder 21 and the lower cylinder 26 are separable from each other to enable the filter membrane 29 to be replaced by the membrane replacement apparatus.
The upper part of the upper cylinder 21 is provided with a plurality of interfaces, for example, an air inlet 24, a light source interface 22 and a detector interface 23. The gas inlet 24 is connected to a sampling tube for collecting atmospheric air. The light source interface 22 may directly mount the light source 11 such as an LED. The light source interface may also be fitted with optical fibers for collecting the light of the light source, which project the collected light onto the filter membrane 29. The detector interface 23 is used to mount a light detector such as a photosensitive probe. The detector interface 23 may also be fitted with a fiber optic head for collecting reflected light, which conducts the collected reflected light to the light detector. The light source interface 22 and the detector interface 23 are arranged such that incident light from the light source 11 is reflected onto the light detector 23 after impinging on the filter membrane 29. The light source interface 22 and the detector interface 23 may be oppositely disposed, for example, with the same magnitude and opposite direction of inclination from the vertical.
The upper cylinder 21 can be raised and lowered vertically to achieve compression or separation from the lower cylinder 26. For example, the upper cylinder 21 may be raised and lowered vertically by a mechanical device connected thereto. The movement of the upper cylinder 21 can also be in the up-down direction and then the left-right direction, or in the left-right direction and then the up-down direction, or in other ways which are not listed, as long as the membrane replacing device can replace the filtering membrane.
The filter membrane holder 25 is disposed between the upper cylinder 21 and the lower cylinder 26, and serves to hold the filter membrane 29. Sealing rubber rings can be arranged between the upper cylinder and the lower cylinder and the filtering membrane clamp 25. The material of the filtering membrane clip adopts polytetrafluoroethylene or other chemically inert materials. When the gas to be measured is collected, the filtering membrane clamp 25 is positioned between the upper cylinder and the lower cylinder, the upper cylinder 21 is controlled by a mechanical device to be pressed downwards, and a closed space is formed between the filtering membrane clamp and the lower cylinder 26.
The lower cylinder 26 is fixed to ensure that it remains stationary when the filter membrane is replaced. The lower cylinder 26 includes a support plate. In the present embodiment, the orifice plate 28 is exemplified as the support plate. The orifice plate 28 is in the form of a screen and is disposed at the upper portion of the lower cylinder. The orifice plate 28 serves to support the filter membrane and maintain the air flow in the space formed by the upper cylinder 21 and the lower cylinder 26.
The lower part of the lower cylinder 26 is provided with an air outlet 27, and the clean gas to be detected after being filtered by the filtering membrane is sent into the detection system from the air outlet 27 so as to detect the gas to be detected.
When the filtering membrane is replaced, the upper air cylinder 21 is lifted, the membrane replacing device rotates, the filtering membrane to be replaced is removed, and a new membrane is replaced. The mechanical device then lowers the upper cylinder 21 and compresses it, and a closed space is formed again by the upper and lower cylinders and the filtering membrane clamp 25, thereby completing the replacement of the filtering membrane once.
In addition, in order to ensure stable pressure inside the gas detection apparatus for detecting the gas to be measured, the sampling air pump for collecting the gas to be measured is kept in an operating state during the replacement of the filtration membrane 29. A three-way electromagnetic valve is arranged behind the outlet 27 of the lower cylinder 26, and the three-way electromagnetic valve is communicated with the lower cylinder 26 during sampling so as to be communicated with a gas detection system. When the filtering membrane is replaced, the three-way electromagnetic valve is switched to the bypass to isolate the membrane replacing device from the sampling channel, so that the gas detection device cannot be influenced when the filtering membrane is replaced. In the process of membrane replacement, filtered gas enters the gas detection device from the bypass, so that the internal pressure of the detection device is stable. And in the film changing process, the detection device idles and does not record data.
[ control Unit ]
The control unit 3 is a processor for controlling each part of the automatic filtration membrane replacement apparatus. The control unit 3 controls the detection unit 1 to detect the intensity of the reflected light from the filtration membrane, and causes the membrane replacement unit 2 to replace the filtration membrane 29 based on the detection result.
Examples of the control unit include a single chip microcomputer integrated with the automatic filtration membrane replacement device, a single chip microcomputer integrated with the gas detection device and the automatic filtration membrane replacement device, a personal computer, a personal terminal, and the like. In addition, the function of the control unit may also be implemented by software.
The detection unit 1 sends the detected intensity of the reflected light to the control unit 3. The control unit receives and saves the detected reflected light intensity. Assume that the reflected light intensity for a new filter membrane (i.e., a filter membrane that is not used to filter the gas to be measured) is I0In aWhich corresponds to the intensity I of the reflected light detected when the filter membrane has been used for a time ttRatio R betweentLess than a predetermined value R0The control unit 3 issues an instruction for replacing the filtration membrane to the membrane replacement unit.
R0The upper limit of the value is 1, the lower limit is determined by the chemical activity of the gas to be detected, the chemically active molecules are lost when passing through the filter membrane, and the losses caused by the filter membrane having a long service time or being contaminated more are relatively large. To detect the atmosphere free radical NO at night3For example, fig. 5 shows an example of the appearance of the filter membrane after use for a different time, wherein the filter membrane on the left is a new filter membrane, the surface of which is now clean. The middle filtering membrane has certain contamination and needs to be replaced. R at this time0The value is about 0.75. The rightmost filter membrane is the filter membrane after being used for a long time, and the contamination degree is serious at the moment.
[ memory cell ]
The storage unit 4 may be, for example, an external memory for storing data on the automatic film changer. The data includes, for example: parameters relating to the filter membranes (brand, model, length of use, intensity of reflected light measured over time, etc., predetermined values R used for different filter membranes0Etc.); parameters regarding the light source (wavelength, light intensity, etc.); and parameters (brand, model, etc.) relating to the detector that detects the reflected light, etc.
The storage unit may further store information about a predetermined value R0In a table containing predetermined values R for different brands, models, properties of the gas to be measured (such as type, concentration, humidity, etc.), wavelength of the light source, etc0The control unit 3 may determine the predetermined value R for a particular filter membrane by calling up the data in the table0The value of (c).
The storage unit may further store information about a predetermined value T0In a table containing predetermined values T for different brands, models, properties of the gas to be measured (such as type, concentration, humidity, etc.), wavelength of the light source, etc0The control unit 3 may determine that a particular pass is targeted by calling the data in the tablePredetermined value T of the filter membrane0The value of (c).
[ automatic film-changing method ]
The method for automatically replacing the filtration membrane according to the present invention will be described in detail with reference to FIGS. 5 to 7.
First, the principle of determining the timing of replacing the filter membrane according to the reflectance of the filter membrane to light in the present invention will be described with reference to fig. 5 and 6.
FIG. 5 shows the filter membrane in an unused, used state for a period of time, and after a longer period of use. As can be seen from fig. 5, when the filter membrane is used for a long time, the contamination on the filter membrane is large, which may result in inaccurate measurement of the gas to be measured.
Figure 6 shows the relationship between the time of use of the filter membrane and the intensity of the reflected light of the filter membrane. As can be seen from fig. 6, as the time of use of the filter membrane increases, the intensity of the reflected light decreases. Therefore, in the present invention, the timing of replacing the filter membrane is determined by detecting the intensity of the reflected light from the filter membrane.
Intensity of reflected light I of the New Filter Membrane0Intensity of reflected light I with the filter membrane having been used for time ttRatio R betweentThe fouling ratio R of the filter membrane, in relation to the degree of fouling of the filter membranetThe smaller. R for determining the timing of replacing the filtration membrane can be measured by performing an experiment before sampling0The value is obtained. For example, the collection of atmospheric night free radical NO3In time, the contaminated filter membrane may result in NO3Loss of (R)0The value may be set at 0.7-0.8; collecting SO2、NOxWhen the species is relatively stable in equal proportion, R0The value may be set at 0.2-0.3.
The method for automatically replacing the filter membrane will be described with reference to fig. 7.
In step S701, the intensity of the reflected light of the light reflected by the filter membrane is detected, and the detected intensity of the reflected light is transmitted to the control unit.
Specifically, the step S701 may include, for example, the following steps:
1. after a new filter membrane is replaced, the control unit sends a starting instruction to the detection unit 1 to start the light source 11;
2. the light emitted from the light source 11 is reflected by the clean filter film 29 and then received by the light detector 12, and the light detector 12 obtains the initial light intensity data I0Sending to a control unit;
3. the control unit sends a closing instruction to close the light source 11, and sends an instruction to a three-way electromagnetic valve communicated with the air outlet 27 to switch the three-way electromagnetic valve to a gas collection channel and start to collect gas;
4. every 5 minutes, the control unit sends out a starting instruction to start the light source 11, and the light detector 12 records the reflected light intensity data I at the momenttAnd the intensity of the reflected light ItAnd sent to the control unit.
In step S702, the intensity I of reflected light detected when the filter membrane is not in use is determined0Intensity of reflected light I detected when the filter membrane has been in use for a time ttRatio R betweentWhether or not it is less than a predetermined value R0。
For example, in the step S702, R is determinedtWhether or not it is less than a predetermined value R0(e.g., 0.5).
When the result of step S702 is YES, R is determinedtLess than a predetermined value R0In the case of (3), step S703 is performed. In step S703, a membrane replacement instruction for instructing the replacement of the filtration membrane is issued to the membrane replacement unit.
Specifically, in step S703, if R is presenttThe value is lower than the set value by 0.5, and the control unit sends a film changing instruction to the film changing unit.
In step S704, the filtration membrane is replaced according to the membrane replacement instruction issued in step S703.
Specifically, in step S704, according to the membrane replacement command, the control unit switches the solenoid valve to the bypass and activates the mechanical device to raise the upper cylinder 21 and cause the membrane replacement unit to replace the filtration membrane.
And when the result of step 702 is NO, determine RtGreater than a predetermined value R0In the case of (3), the process returns to step S701 to continue the next roundAnd (6) judging.
For example, in step S702, if RtAbove this predetermined value, for example 0.5, the control program instructs the light source to be switched off and the sampling of atmospheric gas is continued.
According to the automatic filter membrane replacing device disclosed by the first embodiment of the invention, the contamination condition of the filter membrane can be automatically monitored, and the filter membrane can be replaced at a proper time, so that the waste of the filter membrane can be avoided, the quality of a detection result of the gas to be detected is ensured, and the labor cost can be reduced. For example when it is against highly reactive species in the atmospheric environment (e.g. night free radical NO)3) When the detection is carried out, the invention can accurately determine the time for replacing the filtering membrane and replace the filtering membrane, thereby leading the device for detecting the atmosphere to accurately obtain the measurement result and reducing the workload of people.
[ second embodiment ]
In the first embodiment, the upper cylinder 21 is vertically lifted, the lower cylinder 26 is fixed, and the upper cylinder 21 moves the filter membrane holder 25 and the filter membrane 29 held by the filter membrane holder, thereby enabling the membrane replacement apparatus to perform the replacement of the filter membrane.
The components in this embodiment have the same structure as those in the first embodiment, and are not described again here. The difference is that in the present embodiment, the relative movement relationship of the upper and lower cylinders is reversed, that is, the upper cylinder 21 is fixed, the lower cylinder 26 is moved, the filter membrane clamp 25 is arranged on the lower cylinder 26, when the lower cylinder 26 is moved, the filter membrane clamp 25 is driven to move together, and then the membrane replacing device is used to replace the filter membrane.
The method for automatically replacing the filtering membrane is the same as that in the first embodiment, and is not described herein again.
According to the second embodiment of the present invention, a variation of the automatic filter membrane replacing device is provided, and a worker can adaptively use the automatic filter membrane replacing device according to the whole gas detection system, thereby increasing compatibility with other components of the gas detection system.
[ third embodiment ]
In a first embodiment, the timing of the replacement of the filter membrane is determined by measuring the intensity of the reflected light of the filter membrane.
In the embodiment, the time for replacing the filter membrane is determined by measuring the transmitted light intensity of the filter membrane.
Specifically, the components of the automatic filter membrane replacing device in this embodiment have the same structures as those of the automatic filter membrane replacing device in the first embodiment, and are not described herein again. The difference is that in the present embodiment, the light source 11 and the light detector 12 are located on both sides of the filter membrane, and the light detector 12 detects transmitted light after the light emitted from the light source 11 is transmitted through the filter membrane 29, and determines whether to replace the filter membrane according to the intensity of the transmitted light.
The configuration of the automatic film changer in the third embodiment is described below with reference to fig. 8. Wherein the same reference numerals are used for the same components as in the first embodiment.
As shown in fig. 8, a light source interface 22 and an intake port 24 are provided on the upper cylinder 21. The light source 11 is mounted on the upper cylinder 21 through a light source interface 22. The detector interface 23 and the air outlet 27 are arranged on the lower cylinder 26, and the optical detector 12 is mounted on the lower cylinder 26 through the detector interface 23. The light emitted from the light source 11 passes through the filter film 29 and is incident on the photodetector 12. The light detector 12 measures the transmitted light intensity. Whether to replace the filter membrane 29 is determined based on the transmitted light intensity, and in the case where it is determined that the filter membrane needs to be replaced, the membrane replacement apparatus replaces the filter membrane 29.
Although it is described in the present embodiment that the light source 11 is provided on the upper cylinder 21, the light detector 12 is provided on the lower cylinder 26. However, the present invention is not limited to this, and the positional relationship between the light source 11 and the light detector 12 may be interchanged.
The method for automatically replacing the filter membrane will be described with reference to fig. 9.
In step S901, the transmitted light intensity of the light transmitted by the filter membrane is detected, and the detected transmitted light intensity is sent to a control unit.
Specifically, the step S901 may include, for example, the following steps:
1. after a new filter membrane is replaced, the control unit sends a starting instruction to the detection unit 1 to start the light source 11;
2. the light emitted from the light source 11 is transmitted by the clean filter film 29 and then received by the light detector 12, and the light detector 12 transmits the initial light intensity data I0Sending to a control unit;
3. the control unit sends a closing instruction to close the light source 11, and sends an instruction to a three-way electromagnetic valve communicated with the air outlet 27 to switch the three-way electromagnetic valve to a gas collection channel and start to collect gas;
4. every 5 minutes, the control unit sends a starting instruction to start the light source 11, and the light detector 12 records the transmitted light intensity data I at the momenttAnd transmits the transmitted light intensity to the control unit.
In step S902, the intensity of transmitted light I detected when the filter membrane is not in use is determined0And the intensity of transmitted light I detected when the filter membrane has been in use for a time ttIs a ratio T betweentWhether or not it is less than a predetermined value T0，T0Is a quantity originally determined according to the properties of the gas to be measured, the measurement conditions, the material, the brand, the model and the like of the filtering membrane.
For example, in this step 902, T is determinedtWhether or not it is less than a predetermined value T0(e.g., 0.5).
Wherein the transmission light intensity of the novel filter membrane I0Intensity of transmitted light I with the filter membrane having been used for time ttIs a ratio T betweentThe dirtying ratio T of the filter membrane, in relation to the degree of fouling of the filter membranetThe smaller. T for determining the timing of replacement of the filtration membrane can be measured by performing an experiment before sampling0The value is obtained. For example, the collection of atmospheric night free radical NO3When excessively contaminated filter membranes cause NO3Increased loss of T0The value may be set at 0.7-0.8; collecting SO2、NOxWhen the species is relatively stable in equal proportion, T0The value may be set at 0.2-0.3.
In addition, it is also possible to select the predetermined value T from those stored in advance0In accordance with the information aboutThe predetermined value T to be used is selected using filter membrane information (including but not limited to at least one of brand, model, specification, etc.) and/or information about the gas to be measured (including but not limited to type, concentration, etc.)0. The table includes predetermined values T for different brands, models, gases to be measured, light source wavelengths, and the like0The predetermined value T for a particular filter membrane may be determined by calling the table0The value of (c).
When the result of step S902 is YES, T is determinedtLess than a predetermined value T0In this case, the process proceeds to step S903. In step S903, a membrane replacement instruction for instructing replacement of the filtration membrane is issued to the membrane replacement unit.
Specifically, in step S903, if T is presenttThe value is lower than the set value by 0.5, and the control unit sends a film changing instruction to the film changing unit.
In step S904, the filtration membrane is replaced according to the membrane replacement instruction issued in step S903.
Specifically, in step S904, according to the membrane replacement command, the control unit switches the solenoid valve to the bypass, and raises the upper cylinder 21, for example, by activating a mechanical device, and causes the membrane replacement unit to replace the filtration membrane 29.
When the result of step 902 is negative, T is determinedtGreater than a predetermined value T0In the case of (3), the process returns to step S901 to continue the next round of determination.
For example, in step S902, if TtAbove this predetermined value, for example 0.5, the control program instructs the light source to be switched off and the sampling of atmospheric gas is continued.
According to the automatic filter membrane replacing device provided by the third embodiment of the invention, the contamination condition of the filter membrane can be automatically monitored, and the filter membrane can be replaced at a proper time, so that the waste of the filter membrane can be avoided, the quality of a detection result is ensured, and the labor cost can be reduced.
Although the present invention has been described with reference to the exemplary embodiments, the embodiments are only for illustrating the technical idea and features of the present invention, and the protection scope of the present invention is not limited thereby. Any equivalent variations or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Description of the reference numerals
1 detection unit
2 film changing unit
3 control unit
4 memory cell
11 light source
12 photo detector
21 upper cylinder
22 light source interface
23 Detector interface
24 air inlet
25 filtering membrane clip
26 lower cylinder
27 air outlet
28 orifice plate
29 Filter Membrane
Claims (17)
1. An automatic filter membrane replacing apparatus for a gas component detecting apparatus, comprising:
a detection unit that detects, as a detection result, a transmittance or a reflectance of light by a filter membrane of the gas component detection device; and
a membrane replacement unit that replaces the filtration membrane in response to a detection result of the detection unit satisfying a predetermined condition,
wherein the detection unit includes a laser diode serving as a light source, the laser diode emitting light incident on the filter membrane,
wherein the membrane replacing unit comprises a filtering membrane holding structure which comprises an upper holding member, a lower holding member and a clamping member arranged between the upper holding member and the lower holding member, the clamping member is used for clamping the filtering membrane, and the upper holding member and the lower holding member are detachably arranged oppositely to contain the filtering membrane and form a space as a gas channel,
wherein a lower portion of the lower holder is provided with an air outlet, behind which a three-way electromagnetic valve is provided, the three-way electromagnetic valve being configured to be switched in two modes: a mode in which the lower holder is brought into communication with the gas component detecting apparatus and a mode in which it is switched to a bypass,
wherein the upper retaining piece, the lower retaining piece and the clamping piece are coaxially arranged,
wherein the detection unit is disposed in the upper holder.
2. The automatic filter membrane replacing apparatus according to claim 1, further comprising a control unit for controlling the membrane replacing unit to replace the filter membrane according to a detection result of the detection unit,
wherein the control unit controls the membrane replacing unit to start replacing the filtering membrane under the condition that the detection result of the detection unit meets a preset condition.
3. The automatic filter membrane replacement device according to claim 1,
the transmittance of the filter membrane to light is determined by the intensity of transmitted light I detected when the filter membrane has been in use for a time ttAnd the intensity of transmitted light I detected when the filter membrane is not in use0Ratio of T betweentTo represent; and is
The reflectivity of the filter membrane to light is determined by the intensity of reflected light I detected when the filter membrane has been in use for a time ttIntensity of reflected light I detected when the filter membrane is not in use0Ratio R betweentTo indicate.
4. The automatic filter membrane replacement device according to claim 3, wherein the predetermined condition is one of the following conditions: (1) rtLess than a predetermined value R0(ii) a And (2) TtLess than a predetermined value T0。
5. The automatic filter membrane replacement device according to claim 1, wherein the membrane replacement unit further comprises a filter membrane replacement unit driven by a motor to replace the filter membrane.
6. The automatic filter membrane replacement device according to claim 1, wherein an air inlet, a light source interface and a detector interface are provided on the upper holder; or the upper holding piece is provided with an air inlet and a light source interface, and the lower holding piece is also provided with a detector interface.
7. The automatic filter membrane replacement device according to claim 1, wherein the lower holder comprises a mesh-like support plate provided at an upper portion thereof for supporting the clamps.
8. Automatic filter membrane replacement device according to claim 1, wherein the upper and/or lower holder can be moved to expose the filter membrane.
9. The automatic filter membrane replacement device according to claim 1, wherein the detection unit further comprises:
and the optical detector is used for detecting and storing the intensity of the reflected light of the filter membrane.
10. The automatic filter membrane replacement device according to claim 9, wherein the control unit controls the light source to emit light at predetermined time intervals and controls the detector to detect the intensity of the reflected light of the filter membrane at predetermined time intervals.
11. A membrane exchange mechanism for exchanging a filtration membrane of a gas component detection apparatus, the membrane exchange mechanism comprising:
an upper holder and a lower holder which are disposed opposite to each other in a separable manner; and
a clamping member for clamping the filter membrane and disposed between the upper and lower holders,
wherein a closed space is formed between the upper holder and the lower holder as a gas passage for passing a gas, and the filter membrane clamped by the clamps is disposed between the upper holder and the lower holder,
wherein a lower portion of the lower holder is provided with an air outlet, behind which a three-way electromagnetic valve is provided, the three-way electromagnetic valve being configured to be switched in two modes: a mode in which the lower holder is brought into communication with the gas component detecting apparatus and a mode in which it is switched to a bypass,
wherein the upper retaining piece, the lower retaining piece and the clamping piece are coaxially arranged,
wherein the detection unit of the gas component detection apparatus is provided in the upper holder.
12. The film exchange mechanism of claim 11, wherein an air inlet, a light source interface, and a detector interface are provided on the upper holder, or an air inlet and a light source interface are provided on the upper holder and a detector interface is provided on the lower holder.
13. The film exchange mechanism of claim 11, wherein the lower holder comprises a support plate having a plurality of holes, the support plate being disposed at an upper portion of the lower holder for supporting the clamping member.
14. A membrane exchange mechanism according to claim 13, wherein the upper and/or lower holders are movable to expose the filter membrane.
15. A method for automatically replacing a filter membrane for a gas component detecting apparatus, the method comprising the steps of:
a detection step of detecting the transmittance or reflectance of a filter membrane of the gas component detection apparatus to light as a detection result; and
a membrane replacement step of replacing the filtration membrane in response to a detection result of the detection unit satisfying a predetermined condition,
wherein the detecting step comprises emitting light incident on the filter membrane with a laser diode,
wherein the membrane replacing step performs a membrane replacing operation using a membrane replacing unit including a filtration membrane holding structure including an upper holding member, a lower holding member, and a clamping member provided between the upper holding member and the lower holding member for clamping the filtration membrane, and the upper holding member and the lower holding member are detachably provided oppositely to accommodate the filtration membrane and form a space as a gas passage,
wherein a lower portion of the lower holder is provided with an air outlet, behind which a three-way electromagnetic valve is provided, the three-way electromagnetic valve being configured to be switched in two modes: a mode in which the lower holder is brought into communication with the gas component detecting apparatus and a mode in which it is switched to a bypass,
wherein the upper retaining piece, the lower retaining piece and the clamping piece are coaxially arranged,
wherein a detection unit for performing the detection step is provided in the upper holder.
16. The method for automatically replacing a filtration membrane according to claim 15,
the transmittance of the filter membrane is determined by the intensity of transmitted light I detected when the filter membrane has been used for a time ttAnd the intensity of transmitted light I detected when the filter membrane is not in use0Ratio of T betweentTo represent; and is
The light reflectivity of the filter membrane is determined by the intensity of reflected light I detected when the filter membrane has been used for a time ttIntensity of reflected light I detected when the filter membrane is not in use0Ratio R betweentTo indicate.
17. The method for automatically replacing a filtration membrane of claim 16, the predetermined condition being one of: (1) rtLess than a predetermined value R0(ii) a And (2) TtLess than predeterminedValue T0。
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| CN201910106981.0A CN109724849B (en) | 2019-02-02 | 2019-02-02 | Automatic filter membrane replacing device and method and membrane replacing mechanism |
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| CN201910106981.0A CN109724849B (en) | 2019-02-02 | 2019-02-02 | Automatic filter membrane replacing device and method and membrane replacing mechanism |
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| CN109724849A CN109724849A (en) | 2019-05-07 |
| CN109724849B true CN109724849B (en) | 2020-10-09 |
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| CN105486546A (en) * | 2015-12-02 | 2016-04-13 | 中国科学院理化技术研究所 | Automatic film change apparatus |
| CN105628652A (en) * | 2014-09-03 | 2016-06-01 | 罗伊电子有限公司 | Apparatus and method for measuring contamination of filter |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1766542A (en) * | 2005-10-14 | 2006-05-03 | 华南师范大学 | Six-station automatic circulation and control method for atmosphere particle monitoring, and apparatus therefor |
| CN105628652A (en) * | 2014-09-03 | 2016-06-01 | 罗伊电子有限公司 | Apparatus and method for measuring contamination of filter |
| CN204241341U (en) * | 2014-11-26 | 2015-04-01 | 四川凯乐检测技术有限公司 | A kind of dustiness detecting sensor based on photovoltaic principals |
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