indicator

Abstract

This system detects the deterioration of ozone removal filters, regardless of the type of ozone removal filter used. [Solution] The indicator 1 is installed on the secondary side of the ozone removal filter 10, and the output gas output from the ozone removal filter 10 flows through the through hole 21 of the main body block 2. The main body block 2 has a branch hole 25 that branches off from the through hole 21. The prevention member 20 installed inside the through hole 21 prevents the part of the prevention member 20 that comes into contact with the output gas from deteriorating when the ozone removal function of the ozone removal filter 10 is not degraded, and prevents the output gas from leaking from the through hole 21 to the branch hole 25. Since the pressure in the branch hole 25 does not fluctuate, the display device 7 does not switch the display mode. On the other hand, when the ozone removal function of the ozone removal filter 10 deteriorates, the part of the prevention member 20 that comes into contact with the output gas deteriorates due to ozone, and the output gas leaks from the through hole 21 to the branch hole 25. The display device 7 switches the display mode due to the increase in pressure in the branch hole 25.

Description

Technical Field

[0001] The technical field disclosed in this specification relates to an indicator indicating the state of an ozone removal filter.

Background Art

[0002] Ozone has strong sterilizing power (oxidizing power) and is widely used for the purposes of sterilization, disinfection, deodorization, and odor removal. On the other hand, ozone may affect the human body depending on its concentration. Therefore, safety standards have been established for ozone concentration. For example, in the working environment standards established by the Japanese Society for Occupational Health, the allowable ozone concentration is set at 0.1 ppm or less. In addition, ozone has a characteristic odor. In order to reduce the ozone concentration and suppress the odor of ozone, an ozone removal filter is arranged in a gas flow path through which ozone-containing gas flows. The ozone removal filter includes a filter element that decomposes or adsorbs ozone. The performance of the filter element deteriorates according to the ozone treatment amount. The ozone removal filter needs to replace the filter element whose performance has deteriorated to a certain extent. Conventionally, techniques for detecting the replacement timing or deterioration state of an ozone removal filter have been proposed.

[0003] For example, Patent Document 1 discloses a technique for detecting the deterioration of an ozone decomposition filter by arranging an ozone concentration meter on the downstream side of the ozone decomposition filter and detecting the deterioration of the ozone decomposition filter based on the ozone concentration detected by the ozone concentration meter. This technique is pointed out in Patent Document 1 to be costly because it uses an expensive ozone concentration meter. On the other hand, the ozone decomposition filter deterioration detection device described in Patent Document 1 detects the ozone concentration of the gas during ozone decomposition with an ozone sensor by providing the ozone decomposition filter in two layers and arranging the ozone sensor between the layers, or by providing a notch in the ozone decomposition filter and arranging the ozone sensor in the notch, predicting the ozone concentration after decomposition from the detected ozone concentration, and detecting the deterioration of the ozone decomposition filter. Patent Document 1 describes that an inexpensive ozone concentration detection means can be applied because the ozone sensor only needs to detect the ozone concentration within a detection range higher than the ozone concentration after decomposition. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 3-267748 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Even though ozone sensors can detect ozone concentration over a relatively wide range, they need to detect ozone concentration at the ppm level, making them expensive. The technology described in Patent Document 1 can only detect deterioration in specific ozone decomposition filters equipped with an ozone sensor. Therefore, there is room for improvement in conventional methods of detecting deterioration of ozone decomposition filters by detecting ozone concentration. [Means for solving the problem]

[0006] One embodiment of an indicator made to solve the above problem is (1) an indicator disposed on the secondary side of an ozone removal filter that removes ozone from a gas, which detects the deterioration of the ozone removal filter, and comprising: a main body block having a through hole through which the output gas output from the ozone removal filter flows, and a branch hole branching off from the through hole; a display device that switches the display mode according to the pressure fluctuation of the branch hole; and a prevention member that prevents the output gas from flowing into the branch hole, wherein the prevention performance of the prevention member deteriorates due to ozone.

[0007] In the indicator having the above configuration, the output gas emitted from the ozone removal filter flows through a through-hole in the main block. The prevention member prevents the part that comes into contact with the output gas from deteriorating when the ozone removal function of the ozone removal filter is not degraded, and prevents the output gas from flowing into the branch hole. Since the pressure in the branch hole does not fluctuate, the display device does not switch display modes. On the other hand, when the ozone removal function of the ozone removal filter deteriorates, the part of the prevention member that comes into contact with the output gas deteriorates due to ozone, and the output gas flows into the branch hole. The display device switches display modes in response to the increase in pressure in the branch hole. Therefore, the indicator having the above configuration is inexpensive because it can detect the deterioration of the ozone removal filter by pressure fluctuations in the branch hole without using an ozone concentration meter. Since the indicator is installed on the secondary side of the ozone removal filter, it can detect the deterioration of the ozone removal filter regardless of the type of ozone removal filter.

[0008] (2) In the indicator described in (1), the prevention member comprises a first cylindrical member having a hollow cylindrical shape installed inside the through hole, the first cylindrical member forming an introduction passage between itself and the inner circumferential surface of the through hole for introducing a portion of the output gas into the branch hole; a first O-ring attached to the first cylindrical member at a position upstream of the opening position where the branch hole opens into the through hole and blocking the introduction passage; and a second O-ring attached to the first cylindrical member at a position downstream of the opening position and blocking the introduction passage, wherein it is preferable that one of the first O-ring and the second O-ring is more susceptible to degradation by ozone than the other.

[0009] In the indicator having the above configuration, a portion of the output gas flows into the introduction passage formed between the inner circumferential surface of the through hole and the first cylindrical member. If the ozone removal function of the ozone removal filter is not degraded, the first O-ring and the second O-ring block the introduction passage. Since the internal pressure of the branch hole does not fluctuate, the display device does not switch the display mode. On the other hand, if the ozone removal function of the ozone removal filter deteriorates, one of the two O-rings, the one with lower ozone resistance, deteriorates due to the ozone contained in the output gas and develops a crack. The output gas leaks from the cracked portion of the O-ring towards the branch hole. The other O-ring is less susceptible to deterioration by ozone than the other O-ring and blocks the introduction passage, so the output gas leaked from the other O-ring flows into the branch hole. The display device switches the display mode due to the increase in internal pressure of the branch hole. Therefore, with the above configuration, the deterioration of the ozone removal filter can be detected using inexpensive O-rings.

[0010] (3) In the indicator described in (1), the prevention member is preferably a first cylindrical member having a hollow cylindrical shape installed inside the through hole, the first cylindrical member having an introduction passage between itself and the inner circumferential surface of the through hole for introducing a portion of the output gas into the branch hole, a first O-ring attached to the first cylindrical member at a position upstream of the opening position where the branch hole opens into the through hole, and a second O-ring attached to the first cylindrical member at a position downstream of the opening position, wherein one of the first O-ring and the second O-ring is a sealing O-ring that seals the introduction passage radially, and the other is a deterioration detection O-ring formed of rubber with an unsaturated structure having double bonds as its main chain, attached to the first cylindrical member with an elongation rate equal to or higher than the elongation rate when normally sealed, and sealing the introduction passage radially.

[0011] In the indicator having the above configuration, a portion of the output gas flows into the introduction passage formed between the inner circumferential surface of the through hole and the first cylindrical member, and comes into contact with the first O-ring and the second O-ring. If the ozone removal function of the ozone removal filter is not degraded, the first O-ring and the second O-ring are less prone to deterioration and prevent the output gas from flowing into the branch hole. Since the internal pressure of the branch hole does not fluctuate, the display device does not switch the display mode. On the other hand, if the ozone removal function of the ozone removal filter deteriorates, the O-ring that serves as the deterioration detection O-ring has its molecular double bond broken by the ozone contained in the output gas. The deterioration detection O-ring is normally attached to the first cylindrical member with an elongation rate equivalent to or higher than that during normal sealing. Therefore, stress concentrates at the part where the molecular double bond of the deterioration detection O-ring is broken, making it prone to cracking. The output gas leaks from the cracked part to the branch hole side. The leaked output gas is sealed by a deterioration detection O-ring and a sealing O-ring located on the opposite side of the branch hole opening, and flows into the branch hole. The display device switches the display mode when the internal pressure of the branch hole rises. Therefore, with the above configuration, deterioration of the ozone removal filter can be detected using inexpensive O-rings.

[0012] (4) In the indicator described in (1), the prevention member preferably comprises a cylindrical member in the shape of a cylindrical member installed inside the branch hole, the cylindrical member forming an introduction passage between itself and the inner circumferential surface of the branch hole for introducing a portion of the output gas into the branch hole, and an O-ring attached to the outer circumferential surface of the cylindrical member, wherein the O-ring is made of rubber with an unsaturated structure having double bonds as its main chain, is attached to the cylindrical member with an elongation rate equal to or higher than the elongation rate during normal sealing, and is a deterioration detection O-ring that seals the introduction passage in the radial direction.

[0013] In the indicator having the above configuration, a portion of the output gas flowing through the through hole 21 flows into the introduction passage formed between the inner circumferential surface of the branch hole and the cylindrical member, and comes into contact with the deterioration detection O-ring that seals the introduction passage. If the ozone removal function of the ozone removal filter is not degraded, the deterioration detection O-ring does not deteriorate due to ozone and prevents the output gas from flowing into the branch hole. Since the internal pressure of the branch hole does not fluctuate, the display device does not switch the display mode. On the other hand, if the ozone removal function of the ozone removal filter deteriorates, the deterioration detection O-ring has its molecular double bonds broken by the ozone contained in the output gas. The deterioration detection O-ring is normally attached to the cylindrical member with an elongation rate equal to or higher than that of the normal sealing. Therefore, stress concentrates in the part of the deterioration detection O-ring where the molecular double bonds are broken, making it prone to cracking. The output gas that flows into the introduction passage flows into the branch hole from the cracked part of the deterioration detection O-ring. The display device switches the display mode based on the increase in internal pressure in the branch hole. Therefore, with the above configuration, the deterioration of the ozone removal filter can be detected using an inexpensive O-ring.

[0014] In the indicator described in (5)(3) or (4), it is preferable that the deterioration detection O-ring is incorporated with an elongation rate of 10% or more.

[0015] According to the indicator with the above configuration, variations in the timing of leakage from the deterioration detection O-ring are suppressed, allowing for accurate detection of deterioration of the ozone removal filter.

[0016] In the indicator described in any one of (3) to (5) (6), it is preferable that the material of the deterioration detection O-ring is nitrile rubber.

[0017] In the indicator with the above configuration, the deterioration detection O-ring is made of nitrile rubber with many double bonds, allowing the display mode of the display device to switch responsively in response to the deterioration of the ozone removal filter.

[0018] (7)(2) or (3) In the indicator described, the through hole is a linear hole, and has a hollow cylindrical second cylindrical member disposed between the inner peripheral surface of the through hole and the first cylindrical member. The second cylindrical member can be inserted into the through hole from one of the both ends openings of the through hole, and the first cylindrical member can be inserted into the second cylindrical member from the other of the both ends openings of the through hole. On the outer peripheral surface of the first cylindrical member, a first annular groove for mounting the first O-ring and a second annular groove for mounting the second O-ring are formed, which is preferable.

[0019] The indicator having the above configuration can take out the first cylindrical member from the through hole of the main body block together with the O-ring for deterioration detection and the O-ring for sealing, and can replace the O-ring for deterioration detection, so the maintainability is good.

Effect of the Invention

[0020] According to the above configuration, an inexpensive indicator capable of detecting the deterioration of the ozone removal filter regardless of the type of the ozone removal filter can be provided.

Brief Description of the Drawings

[0021] [Figure 1] It is a cross-sectional view of an ozone removal filter to which an indicator according to the first embodiment is attached. [Figure 2] It is a cross-sectional view of the indicator. [Figure 3] It is an exploded perspective view of the indicator. [Figure 4] It is an enlarged view of part A in FIG. 2, and is a view for explaining the gas flow when notifying the replacement timing of the ozone removal filter. [Figure 5A] It is a view for explaining the deterioration of the deteriorated leak detection seal member. [Figure 5B] It is a view for explaining the deterioration of the leak detection seal member shown in FIG. 5A. [Figure 6] It is a view showing the test result of the gas leak test. [Figure 7] It is a cross-sectional view of an indicator according to the second embodiment. [Figure 8] This is a cross-sectional view showing a first modified example of the indicator. [Figure 9] This is a cross-sectional view showing a second modified example of the indicator. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the indicator disclosed herein will be described in detail with reference to the accompanying drawings. This embodiment discloses an indicator for detecting the deterioration of an ozone removal filter.

[0023] (First Embodiment) <Example of indicator usage> The indicator 1 shown in Figure 1 is installed on the secondary side of the ozone removal filter 10, which removes ozone from the gas. In this embodiment, the indicator 1 is directly connected to the output port 112 of the ozone removal filter 10, but it may also be indirectly connected to the output port 112 using piping. The indicator 1 is integrated with the ozone removal filter 10 in the gas piping through which the compressed gas containing ozone flows, and the output gas output from the output port 112 flows through it. The indicator 1 is configured to detect the deterioration of the ozone removal filter 10. Compressed gas containing ozone is an example of "gas".

[0024] <Ozone removal filter configuration> The ozone removal filter 10 has a replaceable filter element 13 housed in a housing 11. The housing 11 has a cup-shaped housing body 11A, and a flow path block 11B is detachably attached to the opening of the housing, forming a housing space 114 for housing the filter element 13. An input port 111 and an output port 112 are opened coaxially in the flow path block 11B from opposing positions. The input port 111 communicates with the housing space 114 via a communication flow path 115. The output port 112 communicates with the housing space 114 via a mounting opening 113.

[0025] A filter element 13 is detachably attached to the mounting opening 113. The filter element 13 consists of a cylindrical filter member 135 mounted on a rod-shaped sleeve member 131, sandwiched between a first end member 132 and a second end member 133 attached to both ends of the sleeve member 131. The filter member 135 is permeable and has the function of removing ozone from compressed gas passing through it. In this embodiment, the filter member 135 contains activated carbon, and the carbon contained in the activated carbon reacts with the ozone contained in the compressed gas to remove ozone. The filter member 135 may also be a filter member of a different embodiment, such as one containing a material other than activated carbon that can remove ozone, such as zeolite or silica gel.

[0026] The sleeve member 131 has a cylindrical shape with a hollow hole 131a. The sleeve member 131 is formed, for example, in a mesh or porous manner. The filter element 13 has a first end member 132 that is screwed into the mounting opening 113. The first end member 132 has a filter communication hole 132a formed therein to connect the hollow hole 131a and the mounting opening 113.

[0027] The ozone removal filter 10 has a compressed gas supply source (not shown) connected to its input port 111. The ozone removal filter 10 has an indicator 1 connected to its output port 112 via a gasket 8, and secondary piping (not shown) is connected to the indicator 1 via a gasket 9.

[0028] As shown by the arrows in Figure 1, the compressed gas flows from the input port 111 of the ozone removal filter 10 through the communication channel 115, containment space 114, filter element 13, and mounting opening 113 to the output port 112, and is output to secondary piping (not shown) via indicator 1. Ozone is removed from the compressed gas as it passes through the filter member 135 of the filter element 13. The ozone removal function of the filter element 13 deteriorates according to the amount of ozone processed.

[0029] <Indicator Configuration> As shown in Figure 1, the indicator 1 has a display device 7 mounted on the upper surface of the main body block 2, which gives it its appearance. The indicator 1 has a protective member 20 built into the main body block 2.

[0030] As shown in Figures 2 and 3, the main body block 2 has a roughly rectangular block shape. The main body block 2 has holes formed in a T-shape by through holes 21 and branch holes 25. The through holes 21 are formed straight relative to the main body block 2 and open on the left and right sides of the main body block 2 in the figures. The branch holes 25 are formed relative to the main body block 2 so as to communicate with the through holes 21 from the top surface and branch off from the through holes 21. The display device 7 is attached to the main body block 2 so as to communicate with the branch holes 25. The display device 7 will be described later.

[0031] The main body block 2 has stepped portions 22 and 23 formed along the outer circumference of the openings at both ends of the through hole 21 for mounting gaskets 8 and 9. In this embodiment, the main body block 2 is airtightly connected to the flow path block 11B of the ozone removal filter 10 via gasket 8. The main body block 2 is airtightly connected to secondary piping (not shown) via gasket 9. The indicator 1 indicates that the output gas output from the ozone removal filter 10 flows through the through hole 21.

[0032] The prevention member 20 in this embodiment is installed inside the through hole 21. The prevention member 20 is configured to prevent output gas from flowing into the branch hole 25. The prevention performance of the prevention member 20, which prevents output gas from flowing into the branch hole 25, is reduced by ozone. The prevention member 20 in this embodiment includes an outer cylindrical member 3, an inner cylindrical member 4, a deterioration detection O-ring 5, and a sealing O-ring 6. The outer cylindrical member 3 is an example of a "second cylindrical member". The inner cylindrical member 4 is an example of a "first cylindrical member". The deterioration detection O-ring 5 is an example of a "first O-ring". The sealing O-ring 6 is an example of a "second O-ring".

[0033] As shown in Figure 2, the outer cylindrical member 3 is a hollow cylindrical member installed inside the through hole 21. The outer cylindrical member 3 has an outer flange portion 3e that protrudes radially outward along the outer peripheral surface of one end of the cylindrical outer insertion portion 3d. As shown in Figures 2 and 3, the outer cylindrical member 3 is inserted into the through hole 21 from the stepped portion 22 side with the outer insertion portion 3d, and its outer peripheral surface contacts the inner peripheral surface of the through hole 21. The insertion amount of the outer insertion portion 3d into the through hole 21 is uniquely determined by the outer flange portion 3e abutting against the stepped portion 22 of the main body block 2, and the outer insertion portion 3d extends close to the stepped portion 23.

[0034] As shown in Figure 2, the inner cylindrical member 4 is a hollow cylindrical member installed inside the through hole 21. The inner cylindrical member 4 has an inner flange portion 4e that protrudes radially outward along the outer peripheral surface of one end of the cylindrical inner insertion portion 4d. The inner cylindrical member 4 is inserted into the outer cylindrical member 3 installed inside the through hole 21 from the stepped portion 23 side of the inner insertion portion 4d, and its outer peripheral surface contacts the inner peripheral surface of the outer insertion portion 3d. The amount of insertion of the inner insertion portion 4d into the through hole 21 and the outer cylindrical member 3 is uniquely determined by the inner flange portion 4e abutting against the stepped portion 23 of the main body block 2, and the inner insertion portion 4d extends close to the stepped portion 22. The outer cylindrical member 3 and the inner cylindrical member 4 are installed inside the through hole 21 in a nested manner.

[0035] As shown in Figure 1, the indicator 1 in this embodiment suppresses the flow of output gas between the inner circumferential surface of the through hole 21 and the outer insertion portion 3d of the outer cylindrical member 3 by crushing the gasket 8 between the ozone removal filter 10 and the outer flange portion 3e of the outer cylindrical member 3.

[0036] Furthermore, in this embodiment, the indicator 1 is compressed between the inner flange 4e of the inner cylindrical member 4 and a connecting pipe (not shown), thereby suppressing the flow of output gas from the through hole 21 to the connecting pipe (not shown) between the prevention member 20 and the inner circumferential surface of the through hole 21.

[0037] In contrast, with indicator 1, the tip of the inner cylindrical member 4 (the end opposite to the inner flange portion 4e) is located inside the gasket 8, and a portion of the output gas flows between the inner circumferential surface of the hollow portion of the outer cylindrical member 3 and the inner insertion portion 4d of the inner cylindrical member 4.

[0038] As shown in Figures 2 and 4, an introduction passage P is formed between the inner cylindrical member 4 and the outer cylindrical member 3 to introduce a portion of the output gas into the branch hole 25. The sealing O-ring 6 and the deterioration detection O-ring 5 are incorporated into the indicator 1 to radially seal the introduction passage P between the inner cylindrical member 4 and the outer cylindrical member 3.

[0039] The inner cylindrical member 4 has a first annular groove 4a formed in an annular shape along the circumferential direction on the outer circumferential surface of the inner insertion portion 4d, at a position upstream of the opening position 27 where the branch hole 25 opens into the through hole 21. The deterioration detection O-ring 5 is fitted in the first annular groove 4a and blocks the introduction path P at a position upstream of the opening position 27. The inner cylindrical member 4 has a second annular groove 4b formed in an annular shape along the circumferential direction on the outer circumferential surface of the inner insertion portion 4d, at a position downstream of the opening position 27. The sealing O-ring 6 is fitted in the second annular groove 4b and blocks the introduction path P at a position downstream of the opening position 27.

[0040] The sealing O-ring 6 and the deterioration detection O-ring 5 are made of rubber with an unsaturated structure in which double bonds form the main chain. Commercially available O-rings are used for the sealing O-ring 6 and the deterioration detection O-ring 5 so that they can be replaced inexpensively. In this embodiment, nitrile rubber O-rings are used for the sealing O-ring 6 and the deterioration detection O-ring 5.

[0041] The materials of the sealing O-ring 6 and the degradation detection O-ring 5 are not limited to this embodiment. For example, the material of the degradation detection O-ring 5 does not have to be nitrile rubber; it can be natural rubber, styrene-butadiene rubber, or any other rubber with an unsaturated structure whose main chain is a double bond (a bond between two elements involving four bonding electrons). For example, the sealing O-ring 6 may be an O-ring made of ozone-resistant rubber that can prevent ozone degradation without the use of ozone cracking inhibitors, such as fluororubber (FKM), silicone rubber (Q), ethylene propylene rubber (EPM), or acrylic rubber (ACM), or an O-ring with ozone cracking prevention measures.

[0042] The deterioration detection O-ring 5, fitted in the first annular groove 4a, has an elongation rate greater than that of the sealing O-ring 6, fitted in the second annular groove 4b. In this embodiment, the elongation rate is defined as (inner diameter when O-ring is free - outer diameter of shaft) / inner diameter when O-ring is free. For example, the sealing O-ring 6 is fitted in the second annular groove 4b with an elongation rate (2% or less) for normal sealing as specified in JIS 2401. The deterioration detection O-ring 5 is fitted in the first annular groove 4a with an elongation rate (10% or more) higher than the elongation rate (2% or less) for normal sealing as specified in JIS B 2401. The elongation rate of the deterioration detection O-ring 5 will be described later.

[0043] As shown in Figures 2 and 4, the indicator 1 has a first space S1 formed in the portion corresponding to the branch hole 25, where the outer insertion portion 3d of the outer cylindrical member 3 and the inner insertion portion 4d of the inner cylindrical member 4 overlap in the circumferential direction.

[0044] Specifically, as shown in Figure 4, the inner cylindrical member 4 is provided with an inner stepped portion 4c recessed radially inward on the outer circumferential surface of the inner insertion portion 4d, so as to reduce the outer diameter of the inner insertion portion 4d from the tip of the inner insertion portion 4d (left end in the figure) to the position corresponding to the branch hole 25. The outer cylindrical member 3 is provided with an outer stepped portion 3c recessed radially outward on the inner circumferential surface of the outer insertion portion 3d, so as to increase the inner diameter of the outer insertion portion 3d from the tip of the outer insertion portion 3d (right end in the figure) to the position corresponding to the branch hole 25. The first space S1 is formed in an annular shape between the inner stepped portion 4c and the outer stepped portion 3c.

[0045] As shown in Figures 2 and 4, the outer cylindrical member 3 has an annular groove 3b formed on the outer circumferential surface of the outer insertion portion 3d, in the portion corresponding to the branch hole 25. The groove 3b is formed to be recessed radially inward relative to the outer circumferential surface of the outer insertion portion 3d. As a result, a second space S2 is provided in an annular shape in the portion corresponding to the branch hole 25 in the area where the outer circumferential surface of the outer insertion portion 3d and the inner circumferential surface of the through hole 21 come into contact. The outer cylindrical member 3 has a communication hole 3a formed on the groove 3b, and the first space S1 is constantly in communication with the branch hole 25 via the communication hole 3a.

[0046] As shown in Figure 3, the display device 7 has an air lamp 71 attached to the branch hole 25 of the main body block 2 via a joint 72. As shown in Figure 2, the air lamp 71 has a piston chamber 71c formed between a lower member 71a and an upper member 71b, and a piston 71d is slidably loaded into the piston chamber 71c. The piston chamber 71c is airtightly divided into an upper chamber and a lower chamber by the piston 71d. A compression spring 71e is compressed between the piston 71d and the upper member 71b, constantly biasing the piston 71d to retract into the piston chamber 71c. The piston chamber 71c communicates with the branch hole 25 via an introduction passage 71h. Gas flowing into the branch hole 25 is introduced into the piston chamber 71c from the introduction passage 71h via a pressurizing nozzle 71f. The piston 71d moves up and down according to the balance between the biasing force of the compression spring 71e and the internal pressure of the branch hole 25, and can switch the lamp unit 71g on or off. In this configuration, the lamp unit 71g lights up when the switch is ON and turns off when the switch is OFF.

[0047] <Indicator Operation> Next, the operation of indicator 1 will be explained. If the ozone removal filter 10 shown in Figure 1 is not deteriorated, the compressed gas input to input port 111 will have ozone removed by the filter element 13, then flow to output port 112, and output from output port 112 to indicator 1.

[0048] The output gas flows through the hollow section 4f of the inner cylindrical member 4 that constitutes the indicator 1, and then flows into the secondary piping (not shown). At this time, a portion of the output gas flows into the inlet passage P provided on the radially outer side of the hollow section 4f. The deterioration detection O-ring 5 comes into contact with the output gas from which the ozone has been removed. Therefore, the double bonds of the molecules of the deterioration detection O-ring 5 are not broken by the ozone, the occurrence of cracks is suppressed, and leakage of the output gas can be prevented. Since the output gas does not leak from the deterioration detection O-ring 5, the internal pressure of the branch hole 25 does not change. The display device 7 keeps the lamp unit 71g switched off because the piston 71d is pushed down by the compression spring 71e, so the lamp unit 71g remains off. In other words, the indicator 1 does not detect deterioration of the ozone removal filter 10. The operator can see that the lamp unit 71g is off and confirm that the filter element 13 has not deteriorated, or that it is not time to replace the filter element 13.

[0049] The ozone content of the output gas increases according to the ozone processing rate of the filter element 13. When the deterioration detection O-ring 5 comes into contact with the output gas containing ozone, the rubber (nitrile rubber in this embodiment), which has double bonds as its main chain, undergoes a chemical reaction with the ozone, and the double bonds of the molecule are broken. The deterioration detection O-ring 5 is incorporated into the indicator 1 at an elongation rate higher than the elongation rate during normal sealing, and high tensile stress is generated in the part where the double bonds of the molecule are broken. Therefore, cracks CR develop on the surface of the deterioration detection O-ring 5 faster than when it is installed at the elongation rate during normal sealing, for example, as shown in Figures 5A and 5B. The resulting cracks CR tend to propagate due to stress concentration in the deterioration detection O-ring 5. Figure 5A shows a part of the deterioration detection O-ring 5 installed in the first annular groove 4a. Figure 5B shows the cracks CR that have entered the deterioration detection O-ring 5 shown in Figure 5A.

[0050] As shown in Figure 4, the output gas flowing into the inlet path P leaks out through the crack CR in the deterioration detection O-ring 5 towards the branch hole 25 and flows into the first space S1. Since the sealing O-ring 6 radially seals the space between the inner cylindrical member 4 and the outer cylindrical member 3 downstream of the first space S1, the output gas leaking from the deterioration detection O-ring 5 accumulates in the first space S1 and flows from the communication hole 3a to the second space S2. The output gas then flows from the second space S2 to the branch hole 25. As a result, the internal pressure of the branch hole 25 increases.

[0051] When the internal pressure of the branch hole 25 overcomes the spring force of the compression spring 71e, the display device 7 causes the piston 71d to rise, switching the lamp unit 71g from the off state to the on state. The lamp unit 71g is switched from the off state to the on state. In other words, the indicator 1 detects the deterioration of the ozone removal filter 10 and provides notification. The operator can confirm that the filter element 13 has deteriorated or that it is time to replace the filter element 13 by the change in the display mode of the display device 7.

[0052] The sealing O-ring 6 is fitted into the second annular groove 4b with an elongation rate equivalent to that during normal sealing, and therefore experiences less tensile stress than the deterioration detection O-ring 5, which is fitted into the first annular groove 4a with a higher elongation rate than during normal sealing. As a result, even if the sealing O-ring 6 comes into contact with the ozone-containing output gas leaking from the deterioration detection O-ring 5 and the double bonds in its molecules are broken, the tensile stress generated at the broken portion is small, making it less prone to crack CR than the deterioration detection O-ring 5. Furthermore, even if crack CR does occur, it is less likely to propagate. Therefore, the sealing O-ring 6 can continue to prevent leakage of output gas even after crack CR occurs in the deterioration detection O-ring 5.

[0053] When a worker confirms that the filter element 13 is deteriorated or needs replacing, they replace the filter element 13. For example, the worker removes piping (not shown) from the filter element 13 and indicator 1. The worker removes the flow path block 11B from the ozone removal filter 10. The flow path block 11B is removed together with the filter element 13 that screws into the mounting opening 113 and the indicator 1 that is attached to the flow path block 11B. The worker removes the filter element 13 from the mounting opening 113 of the flow path block 11B and installs a new filter element 13 into the mounting opening 113.

[0054] The worker pulls out the inner cylindrical member 4 from the through-hole 21 of the indicator 1 attached to the flow path block 11B. At this time, the deterioration detection O-ring 5 and the sealing O-ring 6 are removed from the indicator 1 together with the inner cylindrical member 4, with the O-rings 5 ​​and 6 still fitted in the first annular groove 4a and 2nd annular groove 4b, respectively. The worker removes the deteriorate detection O-ring 5 with the crack CR from the first annular groove 4a and installs a new deteriorate detection O-ring 5 into the first annular groove 4a. The sealing O-ring 6 can be replaced in the same way. Since the deteriorate detection O-ring 5 and sealing O-ring 6 are commercially available products, they can be easily and inexpensively removed and replaced. The worker pushes the inner cylindrical member 4 into the outer cylindrical member 3 and reassembles it into the indicator 1.

[0055] The operator assembles the flow path block 11B onto the housing body 11A and connects the piping (not shown) to the input port 111 and indicator 1. This completes the replacement of the filter element 13 and restores the performance of the ozone removal filter 10.

[0056] <Regarding the elongation rate of O-rings used for deterioration detection> The deterioration (crack CR) of the deterioration detection O-ring 5 depends on the ozone concentration, elongation rate, and exposure time. The inventors conducted tests in accordance with JIS B2401, attaching O-rings of the same material (nitrile rubber) and shape to an object with varying elongation rates, exposing them to a gas adjusted to a predetermined ozone concentration, and measuring the number of days until crack CR or leakage occurred. The test results are shown in Figure 6.

[0057] As shown in Figure 6, the greater the elongation rate of the O-ring, the shorter the time until cracks (CR) or leaks occur. For example, with a normal sealing elongation rate (2% or less), it takes 13 days for cracks to occur. When the elongation rate exceeds 10%, cracks will occur within a week. Furthermore, the variability in the time it takes for cracks to occur decreases.

[0058] Therefore, when the indicator 1 is fitted with the sealing O-ring 6 with an elongation rate of 2% or less, and the deterioration detection O-ring 5 is fitted with the indicator 1 with an elongation rate of 10% or more, deterioration of the ozone removal filter 10 can be detected early, and the detection accuracy can be improved.

[0059] As explained above, in the indicator 1 of the first embodiment, the output gas output from the ozone removal filter 10 flows through the through hole 21 of the main body block 2. The prevention member 20 prevents the output gas from flowing into the branch hole 25 because, when the ozone removal function of the ozone removal filter 10 is not degraded, the part that comes into contact with the output gas does not deteriorate. Since the pressure in the branch hole 25 does not fluctuate, the display device 7 does not switch the display mode. On the other hand, when the ozone removal function of the ozone removal filter 10 deteriorates, the part of the prevention member 20 that comes into contact with the output gas deteriorates due to ozone, and the output gas flows into the branch hole 25. The display device 7 switches the display mode in response to the increase in pressure in the branch hole 25. Therefore, the indicator 1 of the first embodiment is inexpensive because it can detect the deterioration of the ozone removal filter 10 by pressure fluctuations in the branch hole 25 without using an ozone concentration meter. Since the indicator 1 is installed on the secondary side of the ozone removal filter 10, it can detect the deterioration of the ozone removal filter 10 regardless of the type of ozone removal filter 10.

[0060] Furthermore, in the first embodiment, indicator 1 allows a portion of the output gas to flow into the introduction passage P formed between the inner circumferential surface of the through hole 21 and the inner cylindrical member 4. If the ozone removal function of the ozone removal filter 10 is not degraded, the degradation detection O-ring 5 and the sealing O-ring 6 block the introduction passage P. Since the internal pressure of the branch hole 25 does not fluctuate, the display device 7 does not switch the display mode. On the other hand, if the ozone removal function of the ozone removal filter 10 deteriorates, the degradation detection O-ring 5 deteriorates due to the ozone contained in the output gas, causing a crack CR to form. The output gas leaks from the cracked portion of the degradation detection O-ring 5 towards the branch hole 25. Since the sealing O-ring 6 is less susceptible to deterioration by ozone than the degradation detection O-ring 5 and blocks the introduction passage P, the output gas leaked from the degradation detection O-ring 5 flows into the branch hole 25. The display device 7 switches the display mode due to the increase in the internal pressure of the branch hole 25. Therefore, according to the indicator 1 of the first embodiment, the deterioration of the ozone removal filter 10 can be detected using an inexpensive O-ring.

[0061] (Second Embodiment) Next, the indicator of the second embodiment will be described with reference to Figure 7. In the indicator 101 of the second embodiment, the prevention member 120 is disposed in the branch hole 25. This is different from the first embodiment, in which the prevention member 20 is disposed in the through hole 21. In the following, the differences from the first embodiment will be the main focus of the description, and components common to the first embodiment will use the same reference numerals in the drawings and description as in the first embodiment, and their descriptions will be omitted as appropriate.

[0062] As shown in Figure 7, the prevention member 120 of the indicator 101 includes a cylindrical member 121 and a deterioration detection O-ring 5. The cylindrical member 121 is cylindrical in shape and is fitted into the branch hole 25. An annular groove 121b for mounting the deterioration detection O-ring 5 is formed on the outer circumferential surface 121a of the cylindrical member 121. An annular introduction passage P2 for introducing output gas from the through hole 21 to the branch hole 25 is formed between the inner circumferential surface 25a of the branch hole 25 and the outer circumferential surface 121a of the cylindrical member 121. The deterioration detection O-ring 5 seals the introduction passage P2 radially and blocks the introduction passage P2.

[0063] In the indicator 101 of the second embodiment, a portion of the output gas flowing through the through hole 21 flows into the introduction passage P2 and comes into contact with the deterioration detection O-ring 5 that seals the introduction passage P2. If the ozone removal function of the ozone removal filter 10 is not degraded, the deterioration detection O-ring 5 does not deteriorate due to ozone and prevents the output gas from flowing into the branch hole 25. Since the internal pressure of the branch hole 25 does not fluctuate, the display device 7 does not switch the display mode. On the other hand, if the ozone removal function of the ozone removal filter 10 deteriorates, the deterioration detection O-ring 5 has its molecular double bonds broken by the ozone contained in the output gas. The deterioration detection O-ring 5 is attached to the cylindrical member 121 with an elongation rate equivalent to or higher than that of normal sealing. Therefore, stress concentrates in the part of the deterioration detection O-ring 5 where the molecular double bonds are broken, making it prone to cracking CR. The output gas flowing into the introduction path P2 flows into the branch hole 25 through the cracked portion of the deterioration detection O-ring 5. The display device 7 switches the display mode when the internal pressure of the branch hole 25 rises. Therefore, according to the indicator 101 of the second embodiment, deterioration of the ozone removal filter 10 can be detected using an inexpensive O-ring.

[0064] This embodiment is merely illustrative and does not limit the present invention in any way. Therefore, the present invention can naturally be improved and modified in various ways without departing from its essence.

[0065] For example, as shown in Figure 8 for the indicator 201, the inner diameter of the through-hole 221 may be larger than the diameter of the flow path at the primary connection point of the through-hole 221 (in Figure 8, the port diameter of the output port 112 of the ozone removal filter 10). The prevention member 220 installed inside the through-hole 221 may have an outer cylindrical member 3 and an inner cylindrical member 4 arranged in a nested manner so that the introduction path P for introducing a portion of the output gas into the branch hole 25 is located outside the diameter of the flow path at the primary connection point of the through-hole 21 (in Figure 8, the port opening of the output port 112 of the ozone removal filter 10). The indicator 201 is connected to the output port 112 of the indicator 201 via an intermediate member 210. The intermediate member 210 is provided with a large-diameter stepped portion 210b along the outer circumference of the secondary opening of the connecting flow path 210a in order to allow a portion of the output gas output from the output port 112 to flow into the introduction path P. The output gas from the ozone removal filter 10 flows sequentially through the connecting channel 210a of the intermediate member 210, the large-diameter stepped section 210b, and the inner cylindrical member 4. At this time, a portion of the output gas flows from the large-diameter stepped section 210b into the introduction channel P and comes into contact with the deterioration detection O-ring 5. Similar to the first embodiment, the indicator 201 changes the display mode of the display device 7 as the internal pressure of the branch hole 25 fluctuates according to the deterioration state of the deterioration detection O-ring 5.

[0066] For example, as shown in Figure 9, the prevention member 20 may be positioned in the through-hole 21 such that the inner flange 4e of the inner cylindrical member 4 is the primary side and the outer flange 3e of the outer cylindrical member 3 is the secondary side. In this case, even when the indicator 1 is removed from the ozone removal filter 10 and connected to the secondary side piping, the inner cylindrical member 4 can be removed from the through-hole 21 of the main body block 2 together with the deterioration detection O-ring 5 and the sealing O-ring 6, and the deterioration detection O-ring 5 can be replaced, thus providing good maintainability. In contrast, as in the first embodiment described above, the prevention member 20 is positioned in the through-hole 21 such that the outer flange 3e of the outer cylindrical member 3 is the primary side and the inner flange 4e of the inner cylindrical member 4 is the secondary side. For example, even when the indicator 1 is connected to the output port 112 of the ozone removal filter 10 and removed from the secondary side piping, the inner cylindrical member 4 can be removed from the through-hole 21 of the main body block 2 together with the deterioration detection O-ring 5 and the sealing O-ring 6, and the deterioration detection O-ring 5 can be replaced, thus providing good maintainability.

[0067] For example, the elongation rates of the deterioration detection O-ring 5 and the sealing O-ring 6 are not limited to the above embodiment. For example, the elongation rate of the deterioration detection O-ring 5 may be the same as the elongation rate during normal sealing. However, by incorporating the sealing O-ring 6 into the indicator 1 with an elongation rate of 2% or less, and the deterioration detection O-ring 5 into the indicator 1 with an elongation rate of 10% or more, even if a crack CR occurs in the deterioration detection O-ring 5, the sealing O-ring 6 will not develop a crack CR. This allows the pressure in the branch hole 25 to fluctuate according to the deterioration of the ozone removal filter 10, and the display mode of the display device 7 to be switched. Furthermore, since the variation in the timing of leakage from the deterioration detection O-ring 5 is suppressed, the indicator 1 can accurately detect the deterioration of the ozone removal filter 10.

[0068] For example, the material of the deterioration detection O-ring 5 does not have to be nitrile rubber. However, by forming the deterioration detection O-ring 5 with nitrile rubber that has many double bonds, the display mode of the display device 7 can be switched responsively in accordance with the deterioration of the ozone removal filter 10.

[0069] For example, the first annular groove 4a and the second annular groove 4b may be provided on the outer cylindrical member 3 instead of the inner cylindrical member 4.

[0070] For example, the display device 7 may have a display mode that can be switched depending on the lighting method (continuous lighting, flashing lighting, etc.) and the color of the light. The display device 7 may also be an indicator label that changes color according to the ozone concentration. The display device 7 may also notify of deterioration by making the amount that the piston 71d protrudes from the piston chamber 71c visible from the outside. [Explanation of Symbols]

[0071] 1,101,102 Indicator 2 Main body block 7 Display device 20,120,220 Prevention Member 21 Through holes 25 branch holes

Claims

1. An indicator installed on the secondary side of an ozone removal filter that removes ozone from a gas, for detecting the deterioration of the ozone removal filter, A main body block having a through hole through which the output gas output from the ozone removal filter flows, and a branch hole branching off from the through hole, A display device that switches the display mode according to the pressure fluctuations of the branch hole, A preventive member for preventing the output gas from flowing into the branch hole, wherein the preventive member's performance is reduced by ozone, Having, An indicator configured in such a way.

2. In the indicator described in claim 1, The aforementioned prevention member is A first cylindrical member, which is hollow and cylindrical in shape and installed inside the through hole, has an introduction passage between it and the inner circumferential surface of the through hole for introducing a portion of the output gas into the branch hole, The first O-ring is attached to the first cylindrical member at a position upstream of the opening where the branch hole opens into the through hole, and blocks the introduction path. A second O-ring is attached to the first cylindrical member at a position downstream of the aforementioned opening, and blocks the introduction passage. It has, Of the first O-ring and the second O-ring, one is more susceptible to degradation by ozone than the other. An indicator configured in such a way.

3. In the indicator described in claim 1, The aforementioned prevention member is A first cylindrical member, which is hollow and cylindrical in shape and installed inside the through hole, has an introduction passage between it and the inner circumferential surface of the through hole for introducing a portion of the output gas into the branch hole, A first O-ring is attached to the first cylindrical member at a position upstream of the opening position where the branch hole opens into the through hole, A second O-ring is attached to the first cylindrical member at a position downstream of the aforementioned opening, It has, Of the first O-ring and the second O-ring, One of them is a sealing O-ring that seals the introduction passage radially, The other is a deterioration detection O-ring formed from rubber with an unsaturated structure having double bonds as its main chain, which is attached to the first cylindrical member with an elongation rate equal to or higher than the elongation rate during normal sealing, and which seals the introduction passage radially. An indicator configured in such a way.

4. In the indicator described in claim 1, The aforementioned prevention member is A cylindrical member is installed inside the branch hole, and the cylindrical member forms an introduction passage between itself and the inner circumferential surface of the branch hole for introducing a portion of the output gas into the branch hole. An O-ring is attached to the outer surface of the cylindrical member, It has, The O-ring is formed from rubber with an unsaturated structure having double bonds as its main chain, and is attached to the cylindrical member with an elongation rate equal to or higher than that of normal sealing, thereby sealing the introduction passage radially as a deterioration detection O-ring. An indicator configured in such a way.

5. In the indicator according to claim 3 or claim 4, The aforementioned deterioration detection O-ring is incorporated with an elongation rate of 10% or more. An indicator configured in such a way.

6. In the indicator according to claim 3 or claim 4, The material of the O-ring for detecting deterioration is nitrile rubber. An indicator configured in such a way.

7. In the indicator described in claim 2 or claim 3, The aforementioned through hole is a straight hole, The through hole has a second hollow cylindrical member disposed between the inner circumferential surface and the first cylindrical member, The second cylindrical member can be inserted into the through hole from one of the openings at both ends of the through hole, and the first cylindrical member can be inserted into the second cylindrical member from the other of the openings at both ends of the through hole. The outer circumferential surface of the first cylindrical member is formed with a first annular groove into which the first O-ring is fitted, and a second annular groove into which the second O-ring is fitted. An indicator configured in such a way.

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