Maintenance management method and maintenance management device for liquid sampling valve

Abstract

A maintenance management method of a liquid sampling valve 10 includes: a driving number acquisition step of acquiring a number of times a piston 17 is driven after sealing materials 141 and 142 are newly installed; and a replacement determination step in which, when the number of times the piston 17 has been driven is equal to or greater than a first replacement threshold value, it is determined that the sealing material 141 and 142 need to be replaced regardless of the time elapsed after newly installing the sealing material 141 and 142.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to and the benefit of Japanese Patent Application No. 2023-36040, filed March 8, 2023, which is hereby incorporated by reference herein in its entirety. Technical Field

[0003] The present disclosure relates to a liquid sampling valve maintenance management method and a maintenance management device. Background Art

[0004] It is known that a conventional liquid sampling valve sends a sample gas vaporized from a sample liquid together with a carrier gas to a detector (for example, refer to Patent Document (PTL) 1).

[0005] Reference List

[0006] Patent Literature

[0007] PTL 1:JP H7-34368 U Summary of the Invention

[0008] (Technical Issues)

[0009] According to the liquid sampling valve described in Patent Document 1, sample leakage may occur due to wear of the sealing material. It is necessary to appropriately manage the maintenance of the sealing material.

[0010] Therefore, it would be helpful to provide a maintenance management method and a maintenance management device that can appropriately manage the sealing material of a liquid sampling valve.

[0011] (Solution to the problem)

[0012] (1) A maintenance management method according to at least one embodiment is used to manage the maintenance of a liquid sampling valve. The liquid sampling valve includes: a housing including a sampling chamber and a vaporization chamber, wherein a liquid sample flows through the sampling chamber and the liquid sample is vaporized in the vaporization chamber; a sealing material separating the sampling chamber from the vaporization chamber; a rod configured to enter and exit the vaporization chamber through a hole in the sealing material; and a piston configured to drive the rod. The maintenance management method includes: a drive count acquisition step of acquiring the number of times the piston has been driven after the sealing material is newly installed; and a replacement determination step of determining that the sealing material needs to be replaced when the number of times the piston has been driven is equal to or greater than a first replacement threshold, regardless of the time that has passed since the sealing material was newly installed.

[0013] Determining the need for seal material replacement based on the number of times the piston has been actuated increases the likelihood of replacing worn seal material. In other words, seal material that is not worn is less likely to require replacement. By reducing the need to replace unworn seal material, the cost of material or replacement work, as well as lost opportunities due to gas chromatograph downtime during the time required for replacement work, are reduced.

[0014] The maintenance management method according to aspect (1) may further include a drive data acquisition step of acquiring at least one of a moving speed of the piston or a strain of the sealing material. In the replacement determination step, it is also determined that the sealing material needs to be replaced in at least one of the following situations: when the moving speed of the piston is equal to or greater than a second replacement threshold value, or when the strain of the sealing material is equal to or less than a third replacement threshold value.

[0015] By determining that the sealing material needs to be replaced based on the driving data in addition to the number of times the piston has been driven, it is possible to determine the deterioration of the sealing material that cannot be determined by the number of times the piston has been driven alone. Therefore, the maintenance of the sealing material is appropriately managed.

[0016] (3) The maintenance management method according to the above aspect (2) may also include a replacement time prediction step: generating extrapolated data that predicts the relationship between the number of times the piston has been driven and the piston's moving speed or the strain of the sealing material, and calculating at least one of the following two items as the predicted maintenance time until the sealing material needs to be replaced: the number of times the piston is driven when the piston's moving speed in the extrapolated data is equal to or greater than the second replacement threshold, or the number of times the piston is driven when the strain of the sealing material in the calculated data is equal to or less than the third replacement threshold.

[0017] By predicting maintenance times based on predictions from drive data, users can determine when seal material replacement is necessary, enabling planned replacement. This allows users to develop and implement a plan that incorporates seal material replacement into analytical operations using gas chromatographs.

[0018] (4) The maintenance management method according to any one of aspects (1) to (3) above may further include a retightening determination step before the replacement determination step: when the number of times the piston has been driven is equal to or greater than a first retightening threshold, regardless of the time that has passed after the sealing material is newly installed, it is determined that the nut that applies a load to the sealing material needs to be retightened.

[0019] By re-tightening the nut before replacing the seal material, the frequency of seal material replacement is reduced, thereby reducing the cost of material or replacement work, and the lost opportunity due to downtime of the gas chromatograph during the time it takes to replace the work.

[0020] (5) The maintenance management method according to the above aspect (4), wherein, in the replacement determination step, when re-tightening of the nut has been performed a prescribed number of times or more, determination is made that the sealing material needs to be replaced.

[0021] When the seal material is worn or deteriorated, even when the nut is retightened, a sufficiently tight fit between the seal material and the stem cannot be ensured. By limiting the number of times the nut needs to be retightened, maintenance work that is virtually ineffective is reduced. Thus, maintenance of the seal material of the liquid sampling valve is properly managed.

[0022] (6) A maintenance management apparatus according to at least one embodiment includes: a processor that executes the maintenance management method according to any one of aspects (1) to (5).

[0023] (Beneficial Effects)

[0024] According to the liquid sampling valve maintenance management method and maintenance management device of the present disclosure, maintenance of the sealing material of the liquid sampling valve is appropriately managed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the attached figure:

[0026] Figure 1 is a block diagram illustrating an example configuration of a gas chromatograph;

[0027] Figure 2 is a cross-sectional view of an example configuration of a liquid sampling valve according to an embodiment, showing a state in which a sampling groove is located in a sampling chamber;

[0028] Figure 3 yes Figure 2 An enlarged view of portion A surrounded by a dot-dash line frame;

[0029] Figure 4 is a cross-sectional view of an example configuration of a liquid sampling valve according to an embodiment, showing a state in which a sampling groove is located in a sample supply channel;

[0030] Figure 5 yes Figure 4 An enlarged view of portion B surrounded by a dot-dash line frame;

[0031] Figure 6 is a cross-sectional view showing an example configuration of a liquid sampling valve to which an accelerometer and a strain sensor are attached;

[0032] Figure 7 is a flow chart illustrating an example process of determining operation of a liquid sampling valve according to an embodiment;

[0033] Figure 8 It shows Figure 7A flowchart of an example process for retightening determination in FIG.

[0034] Figure 9 It shows Figure 7 A flowchart of an example process for determining a replacement in FIG.

[0035] Figure 10 is a graph showing an example of a predicted piston speed calculated based on a measured piston speed;

[0036] Figure 11 shows an example configuration of a cylinder with an externally attached accelerometer; and

[0037] Figure 12 Shown is an example configuration of a cylinder with an attached proximity sensor. DETAILED DESCRIPTION

[0038] The present disclosure relates to a liquid sampling valve for a gas chromatograph. In gas chromatography, a quantitatively collected measurement sample of a multi-component mixture is transported into a column along with a carrier gas. The concentration of each component separated in the column is measured, and the concentration of each component is output as a chromatogram. When the sample to be measured is a liquid sample, the liquid sampling valve vaporizes the liquid sample and transports it into the column along with the carrier gas, enabling the gas chromatograph to measure the concentration of the liquid sample.

[0039] The liquid sampling valve includes a liquid sample supply unit, a liquid sample vaporization unit, and a sealing material that separates the supply unit and the vaporization unit. The liquid sampling valve uses a rod with a sampling groove to transport a quantitative liquid sample from the supply unit to the vaporization unit. The liquid sampling valve moves the sampling groove from the supply unit to the vaporization unit via the sealing material by moving the rod, thereby being able to supply the quantitative liquid sample collected in the sampling groove to the vaporization unit. In order to prevent the liquid sample from leaking from the supply unit, the liquid sampling valve needs to be managed so that no gap is generated between the sealing material and the rod. Specifically, in the liquid sampling valve, by tightening the sealing material with a nut, a sufficient load is applied to the rod from the sealing material.

[0040] Here, due to the wear of the sealing material, sample leakage may occur between the sealing material and the rod. Sample leakage will change the shape of the chromatogram and cause problems such as poor measurement reproducibility and unstable baseline of the chromatogram.

[0041] In the liquid sampling valve according to the comparative example, when a problem occurs, the response is to retighten the nut. However, this approach of responding to problems as they arise cannot prevent these problems. Furthermore, to avoid problems caused by wear of the sealing material, the sealing material is replaced during regular maintenance regardless of its wear condition. Although replacing the sealing material can prevent problems, the sealing material is replaced while it is still fully usable, increasing the cost of replacing the sealing material.

[0042] Therefore, the present disclosure describes a liquid sampling valve capable of performing sealing material replacement at an appropriate time and a gas chromatograph using the liquid sampling valve.

[0043] (Sample configuration of gas chromatograph 1)

[0044] like Figure 1 As shown, a gas chromatograph 1 includes a liquid sampling valve 10, a column 20, a detector 30, and a controller 40. Column 20 may also be referred to as a separation tube. Gas chromatograph 1 is an analyzer that uses liquid sampling valve 10 to collect a quantitative multi-component mixed sample and delivers it along with a carrier gas to column 20. Column 20 separates the multi-component mixed sample into its components, detector 30 detects the concentration of each component, and controller 40 outputs the detection results as a gas chromatogram.

[0045] The liquid sampling valve 10 includes a fitting labeled "IN" for inputting a liquid sample and a fitting labeled "OUT" for discharging the liquid sample, so that the liquid sample flows into the interior. In addition, the liquid sampling valve 10 includes a fitting for introducing a carrier gas, which is used to transport the vaporized liquid sample to the column 20. The liquid sampling valve 10 transports the sample gas (i.e., a mixture of the vaporized liquid sample and the carrier gas) to the column 20.

[0046] The column 20 separates each component in the sample gas. The detector 30 detects the concentration of each component separated by the column 20. The detector 30 includes an accessory for discharging the sample gas after the component concentration detection is completed.

[0047] The controller 40 obtains the detection result of the concentration of each component by the detector 30 and outputs the detection result as a chromatogram. The controller 40 also controls the liquid sampling valve 10 to synchronize the collection of the liquid sample with the detection result of the detector 30.

[0048] The controller 40 may include a processor such as a central processing unit (CPU), or a dedicated circuit such as a field programmable gate array (FPGA). The controller 40 may be configured to execute programs that implement the various functions of the gas chromatograph 1. The controller 40 may include a memory. The memory may store information used in the operation of the controller 40, programs that implement the functions of the controller 40, and the like. The memory may serve as a working memory for the controller 40. For example, the memory may be configured as a semiconductor memory. The memory may be configured as a unit separate from the controller 40.

[0049] The gas chromatograph 1 may further include an interface. Example interfaces include communication interfaces for communicating with external devices via wired or wireless means. The interface may include a display device. For example, example display devices include various displays such as liquid crystal displays. The interface may include an audio output device, such as a speaker. The interface may include an input device for receiving input from a user. Example input devices include a keyboard or physical keys, a touch panel or touch sensor, and a pointing device such as a mouse.

[0050] (Example Configuration of Liquid Sampling Valve 10)

[0051] Reference Figures 2 to 5 , describes an example configuration of the liquid sampling valve 10. The liquid sampling valve 10 includes a block 11, a nut 12, a liquid sample block 133, sealing materials 141 and 142, a rod 15, a piston 17, and a cylinder 18. For example, the block 11, the nut 12, the liquid sample block 133, the rod 15, the piston 17, and the cylinder 18 can be composed of a metal material such as stainless steel (SUS) material, and can include various other materials. The sealing materials 141 and 142 can be composed of a resin material such as rubber, and can include various other materials.

[0052] The block 11, nut 12 and liquid sample block 133 are also collectively referred to as the housing of the liquid sampling valve 10. As described below, the housing of the liquid sampling valve 10 includes a sampling chamber 152 (see Figure 3 ) and vaporization chamber 161.

[0053] The liquid sampling valve 10 further includes a pipe 131 through which the liquid sample flows into a sampling chamber 152 defined between the liquid sample block 133 and the sealing materials 141 and 142 (see FIG. Figure 3) in; and piping 132, through which the liquid sample flows out of the sampling chamber 152. The sampling chamber 152 constitutes a part of the liquid sample flow path. The sealing material 141 has a hole defined by the inner wall 141a. In addition, the sealing material 142 has a hole defined by the inner wall 142a. The holes in the sealing materials 141 and 142 are configured to adapt to the shape of the rod 15 described below, and the rod 15 seals these holes by passing through these holes. The sealing materials 141 and 142 are elastic. By tightening the nut 12 to apply a load to the sealing materials 141 and 142, the inner wall 141a of the sealing material 141 and the inner wall 142a of the sealing material 142 are tightly matched with the outer surface of the rod 15. The inner walls 141a and 142a are tightly matched with the outer surface of the rod 15, which enhances the sealing performance of the holes in the sealing materials 141 and 142.

[0054] Sealing material 142 separates sampling chamber 152 from vaporization chamber 161 .

[0055] The liquid sampling valve 10 further includes a pipe 16 . The pipe 16 may be constructed as a glass tube, or may include various other materials. The space inside the pipe 16 is also referred to as a vaporization chamber 161 .

[0056] The block 11 of the liquid sampling valve 10 includes an inner wall 114 that defines a carrier gas passage 113 for supplying a carrier gas to the vaporization chamber 161. The block 11 of the liquid sampling valve 10 includes an inner wall 115 (see Figure 5 ), which defines a space for accommodating the pipe 16. The space defined by the inner wall 115 connects the carrier gas channel 113 to one end of the pipe 16. Figure 5 As shown, the carrier gas is supplied from the carrier gas passage 113 through the space between the pipe 16 and the inner wall 115 and from one end of the pipe 16 to the vaporization chamber 161 .

[0057] The block 11 of the liquid sampling valve 10 includes a heater 111 and a temperature sensor 112 so as to control the temperature of the block 11 including the vaporization chamber 161 to a temperature at which the liquid sample is vaporized.

[0058] The rod 15 is a rod-shaped member. Figure 3 and Figure 5 As shown, the rod 15 includes a sampling groove 151, which is configured to have a smaller diameter than other parts of the rod 15 and can also be called a small diameter portion. The rod 15 is configured to be able to enter and exit the vaporization chamber 161 through the holes in the sealing materials 141 and 142.

[0059] The rod 15 enters or exits the vaporization chamber 161 by the movement of the piston 17. In other words, the piston 17 drives the rod 15. The rod 15 is constructed so that when the piston 17 moves to the position farthest from the sampling chamber 152 in the cylinder 18, the sampling groove 151 is located in the sampling chamber 152, as shown in FIG. Figure 2 In addition, the rod 15 is constructed so that when the piston 17 moves to the position closest to the sampling chamber 152 in the cylinder 18, the sampling groove 151 is located in the vaporization chamber 161, as shown in FIG. Figure 4 shown.

[0060] When driving air is supplied to the cylinder 18, the piston 17 moves. When driving air is supplied to the driving air supply portion 181 provided on the side of the cylinder 18 close to the sampling chamber 152, the piston 17 moves away from the sampling chamber 152. When driving air is supplied to the driving air supply portion 182 provided on the side of the cylinder 18 away from the sampling chamber 152, the piston 17 moves toward the sampling chamber 152. As the piston 17 moves toward or away from the sampling chamber 152 as described above, the sampling groove 151 moves between the sampling chamber 152 and the vaporization chamber 161.

[0061] When located in sampling chamber 152, sampling groove 151 of rod 15 is filled with a liquid sample. As rod 15 moves from sampling chamber 152 toward vaporization chamber 161, sampling groove 151, filled with the liquid sample, passes through the hole defined by inner wall 142a of sealing material 142 and moves from sampling chamber 152 toward vaporization chamber 161. As sampling groove 151 passes through the hole in sealing material 142 and enters vaporization chamber 161, only the liquid sample filled in sampling groove 151 is collected into vaporization chamber 161. The liquid sample filled in sampling groove 151 is also referred to as collected sample 153. Collected sample 153 vaporizes within vaporization chamber 161, becoming sample gas. The sample gas is transported from vaporization chamber 161 to column 20 by a carrier gas.

[0062] (Operation Example of Gas Chromatograph 1)

[0063] The control unit 40 of the gas chromatograph 1 can collect a sample 153 into the vaporization chamber 161 by controlling the movement of the rod 15 of the liquid sampling valve 10. The amount of sample 153 collected is determined quantitatively based on the volume of the sampling slot 151. Therefore, the gas chromatograph 1 can collect a quantitative amount of liquid sample into the vaporization chamber 161. The quantitative amount of liquid sample is vaporized into sample gas in the vaporization chamber 161, and this sample gas is transported to the column 20 by a carrier gas. The controller 40 synchronizes the timing of collecting the liquid sample by moving the sampling slot 151 of the rod 15 to the vaporization chamber 161 with the operation of separating each component of the collected sample gas by the column 20. Each component of the sample gas separated in the column 20 is sequentially transported to and detected by the detector 30. The controller 40 generates a chromatogram based on the detection results of each component of the sample gas separated by the column 20.

[0064] In gas chromatograph 1, each time a liquid sample is collected to measure the concentration of each component in the liquid sample, piston 17 drives rod 15 to reciprocate once in the axial direction of rod 15. The number of times piston 17 is driven, also called the number of times, corresponds to the number of analyses performed by gas chromatograph 1.

[0065] (Maintenance of liquid sampling valve 10)

[0066] As described above, in the gas chromatograph 1, each time a liquid sample is collected and analyzed, the rod 15 reciprocates once in the axial direction. This axial movement of the rod 15 causes wear on the inner wall 141a of the sealing material 141 and the inner wall 142a of the sealing material 142, which are in contact with the rod 15. The wear of the inner walls 141a and 142a increases the likelihood of a gap forming between the outer surface of the rod 15 and the inner walls 141a and 142a. This gap between the outer surface of the rod 15 and the inner walls 141a and 142a reduces the sealing performance of the sealing material 141 or 142 with respect to the sampling chamber 152. This reduced sealing performance of the sampling chamber 152 increases the likelihood of the liquid sample leaking into the vaporization chamber 161. When the liquid sample leaks into the vaporization chamber 161, even before the sampling groove 151 of the rod 15 moves into the vaporization chamber 161, the liquid sample is vaporized and transported to the column 20. As a result, the amount of sample gas transported to the column 20 becomes unstable. In the liquid sampling valve 10 , maintenance is performed on the liquid sampling valve 10 to maintain the sealing performance of the sampling chamber 152 .

[0067] <Replacement of Sealing Materials 141 and 142>

[0068] The sealing materials 141 and 142 may be replaced as maintenance to maintain the sealing property of the sampling chamber 152. The controller 40 of the gas chromatograph 1 according to the present embodiment determines the necessity of replacing the sealing materials 141 and 142 based on the driving data of the liquid sampling valve 10.

[0069] <Replacement based on the number of drives>

[0070] After the sealing materials 141 and 142 are newly installed in the liquid sampling valve 10, the controller 40 of the gas chromatograph 1 accumulates the number of times the piston 17 of the liquid sampling valve 10 has been driven, and determines the necessity of replacing the sealing materials 141 and 142 based on the number of times the piston 17 has been driven. When the controller 40 determines that the sealing materials 141 and 142 need to be replaced, the controller 40 outputs an alarm to prompt the user to replace the sealing materials 141 and 142. The controller 40 can obtain the number of times the piston 17 has been driven by accumulating the total number by the controller 40 itself or by obtaining the number of times the piston 17 has been driven accumulated by another device. The operation of obtaining the number of times the piston 17 has been driven may also be referred to as a drive number acquisition step. The operation of determining the necessity of replacing the sealing materials 141 and 142 may also be referred to as a replacement determination step.

[0071] For example, when the number of times the piston 17 is driven is greater than or equal to a prescribed threshold, the controller 40 may determine that the sealing materials 141 and 142 need to be replaced, and thus output an alarm to prompt the user to replace the sealing materials 141 and 142. The prescribed threshold, which is compared with the number of times the piston 17 is driven to determine the necessity of replacing the sealing materials 141 and 142, may also be referred to as a first replacement threshold. The first replacement threshold may be determined based on the results of a wear test of the sealing materials 141 and 142, the number of times the piston 17 is driven when a problem related to the sealing materials 141 and 142 occurs during operation of the gas chromatograph 1, and the like. Regardless of the length of time that has passed since the sealing materials 141 and 142 were newly installed, the controller 40 determines the replacement of the sealing materials 141 and 142 based on the number of times the piston 17 is driven.

[0072] In the case of replacing the sealing materials 141 and 142 at the time of periodic inspection of the gas chromatograph 1 or the liquid sampling valve 10, the sealing materials 141 and 142 are replaced based on the time that has passed since the sealing materials 141 and 142 were newly installed in the liquid sampling valve 10. In other words, regardless of the number of times the piston 17 is driven, the sealing materials 141 and 142 are replaced only after they have been installed in the liquid sampling valve 10 for a long time. Therefore, the sealing materials 141 and 142 can be replaced when they are not in a worn state.

[0073] On the other hand, as in the liquid sampling valve 10 according to the present embodiment, by replacing the sealing materials 141 and 142 when the number of times the piston 17 is driven is equal to or greater than the first replacement threshold value, the sealing materials 141 and 142 are likely to have been worn out at the time of replacement, regardless of the time that has passed since the sealing materials 141 and 142 were newly installed. Therefore, the replacement of the sealing materials 141 and 142 is appropriately managed.

[0074] If the user waits until a problem occurs in the gas chromatograph 1 before replacing the sealing materials 141 and 142, the user cannot determine when to replace the sealing materials 141 and 142, and thus cannot replace the sealing materials 141 and 142 in a planned manner. In this case, the performance of analytical work using the gas chromatograph 1 is negatively affected.

[0075] On the other hand, as in the liquid sampling valve 10 according to the present embodiment, the sealing materials 141 and 142 are replaced when the number of times the piston 17 is driven is equal to or greater than the first replacement threshold value, so the user can determine when to replace the sealing materials 141 and 142, thereby enabling planned replacement of the sealing materials 141 and 142. Therefore, the user can develop a plan that incorporates the replacement work of the gas chromatograph 1 into the analysis work using the gas chromatograph 1 and implement the plan.

[0076] Appropriately managing when to replace the sealing materials 141 and 142 or performing planned operations reduces the cost of materials and operations spent on replacing the sealing materials 141 and 142, or reduces losses caused by reduced availability of analytical operations using the gas chromatograph 1.

[0077] <Replacement Based on the Speed ​​of Piston 17>

[0078] like Figure 6 As shown, the liquid sampling valve 10 may include an accelerometer 171 attached to the piston 17. The accelerometer 171 can measure the acceleration of the piston 17 when it moves in the axial direction of the rod 15. The controller 40 of the gas chromatograph 1 can be communicatively connected to the accelerometer 171 via a cable 172. The controller 40 can also be communicatively connected to the accelerometer 171 wirelessly.

[0079] Controller 40 obtains the acceleration of piston 17 from accelerometer 171 and calculates the movement speed of piston 17 when piston 17 is driven. Controller 40 can obtain the movement speed of piston 17 by calculating the movement speed, or it can obtain the movement speed of piston 17 from another device. The movement speed of piston 17 is consistent with the movement speed of rod 15 in the axial direction. When the tight fit between at least one of sealing materials 141 or 142 and rod 15 decreases due to wear of sealing materials 141 or 142, the friction force experienced by rod 15 from sealing materials 141 or 142 during axial movement decreases. When the pressure of the driving gas driving piston 17 is constant, the lower the friction force experienced by rod 15, the faster rod 15 moves in the axial direction, and therefore the faster piston 17 moves. Based on the calculated movement speed of piston 17, controller 40 can assess the tight fit between at least one of sealing materials 141 or 142 and rod 15, thereby determining the need to replace sealing materials 141 or 142.

[0080] Specifically, when the movement speed of the piston 17 is equal to or greater than a specified threshold, the controller 40 may output an alarm to prompt the user to replace the sealing materials 141 and 142. The specified threshold, which is compared with the movement speed of the piston 17 to determine whether to replace the sealing materials 141 and 142, may also be referred to as a second replacement threshold. The second replacement threshold may be determined based on, for example, the actual value of the movement speed of the piston 17 when a problem with the sealing materials 141 and 142 occurs during operation of the gas chromatograph 1.

[0081] According to this embodiment, even if controller 40 determines that sealing materials 141 and 142 do not need to be replaced based on the number of times piston 17 has been driven, controller 40 can still determine the necessity of replacing sealing materials 141 and 142 based on the movement speed of piston 17. By determining based on the movement speed of piston 17 in addition to the number of times piston 17 has been driven, it is possible to determine deterioration of sealing materials 141 or 142, which cannot be determined based solely on the number of times piston 17 has been driven. As a result, replacement of sealing materials 141 and 142 can be appropriately managed.

[0082] The controller 40 can confirm that the piston 17 has completed its movement in the cylinder 18 by acquiring the measurement results of the accelerometer 171. On the other hand, in the liquid sampling valve 10, by supplying the driving air from the driving air supply portion 182 for a sufficient time, it is ensured that the piston 17 has completed its movement in the direction from the sampling chamber 152 to the vaporization chamber 161. Even when the accelerometer 171 is not needed to confirm the completion of the movement of the piston 17, the accelerometer 171 is used for the management of the sealing materials 141 and 142.

[0083] <Replacement of Sealing Material 141 or 142 Based on Strain>

[0084] like Figure 6 As shown, the liquid sampling valve 10 may include a strain sensor 143 attached to the sealing material 142. The strain sensor 143 may be configured to measure the compressive strain caused by the sealing material 142 being pushed outward from the inner wall 142a. The strain sensor 143 may be configured to measure the shear strain in the sealing material 142 caused by the friction force acting on the inner wall 142a of the sealing material 142 by the axially moving rod 15. The controller 40 of the gas chromatograph 1 may be communicatively connected to the strain sensor 143 via a cable 144. The controller 40 may also be communicatively connected to the strain sensor 143 wirelessly.

[0085] Controller 40 obtains the strain of sealing material 142 from strain sensor 143. When the inner diameter of the hole defined by inner wall 142a increases due to wear of sealing material 142, the compressive force acting on inner wall 142a of sealing material 142 from rod 15 decreases. Furthermore, when the tight fit between sealing material 142 and rod 15 decreases due to wear of sealing material 142, the frictional force exerted on sealing material 142 by rod 15 decreases while the pressure of the driving air driving piston 17 remains constant. The lower the frictional force exerted on sealing material 142, the smaller the shear strain exerted on sealing material 142. Therefore, regardless of whether strain sensor 143 measures compressive strain or shear strain, controller 40 can assess the wear of sealing material 142 based on the strain of sealing material 142 measured by strain sensor 143, thereby determining the need to replace sealing material 142.

[0086] The strain sensor 143 may also be attached to the sealing material 141. When the strain sensor 143 is attached to the sealing material 141, the controller 40 may evaluate the wear of the sealing material 141 based on the strain of the sealing material 141 measured by the strain sensor 143, thereby determining the necessity of replacing the sealing material 141.

[0087] When measuring the compressive force acting on the sealing material 141 or 142 from the rod 15 , the strain sensor 143 may be replaced by a load sensor such as a pressure sensor or a load cell.

[0088] Specifically, when the strain of the sealing material 141 or 142 is equal to or less than a specified threshold, the controller 40 may output an alarm to prompt the user to replace the sealing material 141 or 142. The specified threshold, which is compared with the strain of the sealing material 141 or 142 to determine whether to replace the sealing material 141 or 142, may also be referred to as a third replacement threshold. The third replacement threshold may be determined based on, for example, the actual value of the strain of the sealing material 141 or 142 when a problem associated with the sealing material 141 or 142 occurs during operation of the gas chromatograph 1.

[0089] According to this embodiment, even when controller 40 determines that sealing material 141 or 142 does not need to be replaced based on the number of times piston 17 has been driven, controller 40 can further determine the necessity of replacing sealing material 141 or 142 based on the strain of sealing material 141 or 142. By determining based on the strain of sealing material 141 or 142 in addition to the number of times piston 17 has been driven, it is possible to determine deterioration of sealing material 141 or 142, which cannot be determined based solely on the number of times piston 17 has been driven. As a result, replacement of sealing material 141 or 142 can be appropriately managed.

[0090] The movement speed of piston 17 and the strain of sealing material 141 or 142 may also be referred to as drive data. In other words, the drive data includes at least one of the movement speed of piston 17 or the strain of sealing material 141 or 142. The drive data may include the number of times piston 17 has been driven. Controller 40 may determine the need to replace sealing material 141 or 142 based on the drive data. The operation of acquiring the drive data may also be referred to as a drive data acquisition step.

[0091] <Re-tighten nut 12>

[0092] As a maintenance operation to maintain the sealing properties of the sampling chamber 152, the nut 12 can be re-tightened so that a sufficient load is applied to the sealing materials 141 and 142 to ensure a tight fit between the sealing materials 141 and 142 and the rod 15. By re-tightening the nut 12 as a maintenance operation before replacing the sealing materials 141 and 142, the cost of the material or replacement operation, the opportunity lost due to the downtime of the gas chromatograph 1 during the period of time required for the replacement operation, etc. can be reduced. The controller 40 of the gas chromatograph 1 according to this embodiment determines the necessity of re-tightening the nut 12 based on the drive data of the liquid sampling valve 10.

[0093] The controller 40 may accumulate the number of times the piston 17 of the liquid sampling valve 10 is actuated, and based on the number of actuations, determine the necessity of retightening the nut 12. When the controller 40 determines that the nut 12 needs to be retightened, the controller 40 may output an alarm to prompt the user to retighten the nut 12. The operation of determining the necessity of retightening the nut 12 may also be referred to as a retightening determination step.

[0094] For example, when the number of times the piston 17 is actuated is equal to or greater than a specified threshold, the controller 40 may determine that the nut 12 needs to be retightened, and accordingly, output an alarm to prompt the user to retighten the nut 12. The specified threshold, which is compared with the number of times the piston 17 is actuated to determine whether the nut 12 should be retightened, may also be referred to as a first retightening threshold. The first retightening threshold may be determined based on the results of a wear test of the sealing materials 141 and 142, the number of times the piston 17 is actuated when a problem with the sealing materials 141 and 142 occurs during operation of the gas chromatograph 1, or the like. Regardless of the length of time that has passed since the sealing materials 141 and 142 were newly installed, the controller 40 determines whether the nut 12 needs to be retightened based on the number of times the piston 17 is actuated.

[0095] When the movement speed of the piston 17 of the liquid sampling valve 10 is equal to or greater than a prescribed threshold, the controller 40 may output an alarm to prompt the user to retighten the nut 12. The prescribed threshold, which is compared with the movement speed of the piston 17 to determine whether to retighten the nut 12, may also be referred to as a second retightening threshold. The second retightening threshold may be determined based on, for example, the actual value of the movement speed of the piston 17 when a problem with the sealing materials 141 and 142 occurs during operation of the gas chromatograph 1.

[0096] When the strain of the sealing material 141 or 142 of the liquid sampling valve 10 is equal to or less than a specified threshold, the controller 40 may output an alarm to prompt the user to retighten the nut 12. The specified threshold value, compared with the strain of the sealing material 141 or 142 to determine whether to retighten the nut 12, may also be referred to as a third retightening threshold value. The third retightening threshold value may be determined based on, for example, the actual value of the strain of the sealing material 141 or 142 when a problem related to the sealing material 141 or 142 occurs during operation of the gas chromatograph 1.

[0097] According to this embodiment, even when controller 40 determines that retightening of nut 12 is unnecessary based on the number of times piston 17 has been driven, controller 40 can still determine the necessity of retightening nut 12 based on the movement speed of piston 17 or the strain of sealing material 141 or 142. By determining based on the movement speed of piston 17 or the strain of sealing material 141 or 142 in addition to the number of times piston 17 has been driven, it is possible to determine deterioration of sealing material 141 or 142, which cannot be determined based solely on the number of times piston 17 has been driven. Consequently, retightening of nut 12 is appropriately managed.

[0098] When the sealing material 141 or 142 is worn or deteriorated, a sufficiently tight fit between the sealing material 141 or 142 and the rod 15 cannot be ensured even when the nut 12 is retightened. The controller 40 of the gas chromatograph 1 can manage the liquid sampling valve 10 so that the number of times the nut 12 is retightened is less than a prescribed number. The prescribed number can be determined based on a correlation between the number of times the nut 12 has been retightened and the actual frequency of occurrence of problems with the sealing materials 141 and 142. The controller 40 can set the prescribed number to one or two or more times. When the prescribed number is set to zero, the controller 40 does not determine the necessity of retightening the nut 12, but determines the necessity of replacing the sealing materials 141 and 142 from the beginning.

[0099] When retightening the nut 12 does not ensure a sufficiently tight fit between the sealing material 141 or 142 and the stem 15, little maintenance benefit is gained by retightening the nut 12. By limiting the number of times retightening the nut 12 is performed, maintenance work with minimal effect is reduced. As a result, maintenance of the liquid sampling valve 10 is properly managed.

[0100] After the nut 12 has been retightened a prescribed number of times, the controller 40 of the gas chromatograph 1 according to the present embodiment determines the necessity of replacing the sealing materials 141 and 142. That is, the controller 40 of the gas chromatograph 1 according to the present embodiment does not determine the necessity of replacing the sealing materials 141 and 142 until the nut 12 has been retightened a prescribed number of times. The determination of the necessity of retightening the nut 12 and the determination of the necessity of replacing the sealing materials 141 and 142 are not limited to the above-described combination, but can be performed in an appropriately modified combination.

[0101] <Example Procedure of Maintenance Management Method of Liquid Sampling Valve 10>

[0102] The controller 40 of the gas chromatograph 1 can execute a maintenance management method for the liquid sampling valve 10, which includes: Figure 7 、 Figure 8 and Figure 9 The maintenance management method of the liquid sampling valve 10 may be implemented as a maintenance management program executed by a processor constituting the controller 40 of the gas chromatograph 1. The maintenance management program may be stored on a non-transitory computer-readable storage medium.

[0103] The controller 40 obtains the driving data of the gas chromatograph 1 (step S1). The driving data includes the number of times the piston 17 is driven. The driving data may include the measurement result of the acceleration or speed when the piston 17 is driven. The driving data may include the measurement result of the compressive strain of the sealing material 141 or 142, or the measurement result of the compressive force acting on the sealing material 141 or 142 from the rod 15. The driving data may include the measurement result of the shear strain in the sealing material 141 or 142 when the piston 17 is driven.

[0104] The controller 40 determines whether the number of times the nut 12 is re-tightened after the new sealing materials 141 and 142 are replaced is equal to or greater than the prescribed number (step S2). When the number of times the nut 12 is re-tightened is not equal to or greater than the prescribed number (step S2: No), that is, when the number of times the nut 12 is re-tightened is less than the prescribed number, the controller 40 proceeds to step S3, i.e., the process of determining the re-tightening of the nut 12, and performs Figure 8 When the number of times the nut 12 is re-tightened is equal to or greater than the prescribed number of times (step S2: yes), the controller 40 proceeds to step S4, i.e., the replacement determination process of the sealing materials 141 and 142, and executes Figure 9 The process of the flowchart shown in FIG. Figure 8 or Figure 9 After the process shown in the flowchart, the controller 40 ends Figure 7 Execution of the process shown in the flowchart.

[0105] The controller 40 performs the following operations: Figure 7 The process of step S3, Figure 8 The controller 40 determines whether the number of times the piston 17 has been driven is equal to or greater than a first retightening threshold value (step S31). When the number of times the piston 17 has been driven is equal to or greater than the first retightening threshold value (step S31: Yes), the controller 40 proceeds to step S34.

[0106] When the number of times the piston 17 has been driven is not equal to or greater than the first retightening threshold value (step S31: No), that is, when the number of times the piston 17 has been driven is less than the first retightening threshold value, the controller 40 determines whether the moving speed of the piston 17 is equal to or greater than the second retightening threshold value (step S32). When the moving speed of the piston 17 is equal to or greater than the second retightening threshold value (step S32: Yes), the controller 40 proceeds to step S34.

[0107] When the moving speed of the piston 17 is not equal to or greater than the second retightening threshold value (step S32: No), that is, when the moving speed of the piston 17 is less than the second retightening threshold value, the controller 40 determines whether the strain of the sealing material 141 or 142 is equal to or less than the third retightening threshold value (step S33). When the strain of the sealing material 141 or 142 is equal to or less than the third retightening threshold value (step S33: Yes), the controller 40 proceeds to step S34. When the strain of the sealing material 141 or 142 is not equal to or less than the third retightening threshold value (step S33: No), that is, when the strain of the sealing material 141 or 142 is greater than the third retightening threshold value, the controller 40 determines that there is no need to retighten the nut 12, and ends. Figure 8 Execution of the process shown in the flowchart.

[0108] When at least one of the following conditions is true, the controller 40 determines that the nut 12 needs to be retightened, and outputs a retightening alarm to prompt the user to retighten the nut 12 (step S34): determining that the number of times the piston 17 is driven is equal to or greater than the first retightening threshold value (step S31: yes), determining that the moving speed of the piston 17 is equal to or greater than the second retightening threshold value (step S32: yes), or determining that the strain of the sealing material 141 or 142 is equal to or less than the third retightening threshold value (step S33: yes). After executing the process in step S34, the controller 40 ends. Figure 8 Execution of the process in the flowchart.

[0109] The controller 40 performs the following operations: Figure 7 The process of step S4, Figure 9The process of the replacement determination flowchart shown in FIG. The controller 40 determines whether the number of times the piston 17 has been driven is equal to or greater than a first replacement threshold value (step S41). When the number of times the piston 17 has been driven is equal to or greater than the first replacement threshold value (step S41: YES), the controller 40 proceeds to step S44.

[0110] When the number of times the piston 17 has been driven is not equal to or greater than the first replacement threshold (step S41: No), that is, the number of times the piston 17 has been driven is less than the first replacement threshold, the controller 40 determines whether the movement speed of the piston 17 is equal to or greater than the second replacement threshold (step S42). When the movement speed of the piston 17 is equal to or greater than the second replacement threshold (step S42: Yes), the controller 40 proceeds to step S44.

[0111] When the moving speed of the piston 17 is not equal to or greater than the second replacement threshold (step S42: No), that is, when the moving speed of the piston 17 is less than the second replacement threshold, the controller 40 determines whether the strain of the sealing material 141 or 142 is equal to or less than the third replacement threshold (step S43). When the strain of the sealing material 141 or 142 is equal to or less than the third replacement threshold (step S43: Yes), the controller 40 proceeds to step S44. When the strain of the sealing material 141 or 142 is not equal to or less than the third replacement threshold (step S43: No), that is, when the strain of the sealing material 141 or 142 is greater than the third replacement threshold, the controller 40 determines that the sealing materials 141 and 142 do not need to be replaced, and ends. Figure 8 The execution of the process shown in the flowchart.

[0112] When at least one of the following conditions is true, the controller 40 determines that the sealing materials 141 and 142 need to be replaced, and outputs a replacement alarm to prompt the user to replace the sealing materials 141 and 142 (step S44): it is determined that the number of times the piston 17 is driven is equal to or greater than the first replacement threshold (step S41: yes), it is determined that the moving speed of the piston 17 is equal to or greater than the second replacement threshold (step S42: yes), or it is determined that the strain of the sealing material 141 or 142 is equal to or less than the third replacement threshold (step S43: yes). After executing the process in step S44, the controller 40 ends. Figure 8 Execution of the process in the flowchart.

[0113] (summary)

[0114] As described above, according to the maintenance management method for the gas chromatograph 1 of this embodiment, the replacement of the sealing materials 141 and 142 is managed based on the number of times the piston 17 of the liquid sampling valve 10 is driven. By managing the replacement of the sealing materials 141 and 142 based on the number of times the piston 17 is driven, the sealing materials 141 and 142 are more likely to be replaced when they are worn. In other words, the sealing materials 141 and 142 that are not worn are less likely to be replaced. By reducing the replacement of the sealing materials 141 and 142 that are not worn, the cost of materials or replacement work, the opportunity lost due to the downtime of the gas chromatograph 1 during the time period required for the replacement work, and so on are reduced.

[0115] Furthermore, as a maintenance operation of the liquid sampling valve 10, retightening of the nut 12 can be performed based on the number of times the piston 17 has been driven before replacing the sealing materials 141 and 142. By retightening the nut 12 before replacing the sealing materials 141 and 142, the cost of materials or replacement work, the opportunity lost due to downtime of the gas chromatograph 1 during the period of time required for the replacement work, and the like are reduced.

[0116] As maintenance work of the liquid sampling valve 10 , the sealing materials 141 and 142 are replaced or the nut 12 is retightened based on the number of times the piston 17 is driven, so that maintenance of the sealing materials 141 and 142 is appropriately managed.

[0117] Furthermore, by managing the maintenance of the sealing materials 141 and 142 based on the number of times the piston 17 is driven, the user can determine when to maintain the sealing materials 141 and 142, thereby enabling planned replacement of the sealing materials 141 and 142 and retightening of the nut 12. As a result, the user can develop a plan that incorporates replacement work of the gas chromatograph 1 into analysis work using the gas chromatograph 1 and implement the plan.

[0118] According to the gas chromatograph 1 and the liquid sampling valve 10 of this embodiment, it is possible to appropriately manage or plan the maintenance timing of the sealing materials 141 and 142. Therefore, the cost of materials and work spent on maintaining the sealing materials 141 and 142 is reduced, or the loss caused by the reduced availability of analytical work using the gas chromatograph 1 is reduced.

[0119] Furthermore, the maintenance of the sealing materials 141 and 142 can be managed based on the movement speed of the piston 17 or the strain of the sealing material 141 or 142. By managing the maintenance of the sealing materials 141 and 142 based not only on the number of times the piston 17 is driven but also on other drive data of the liquid sampling valve 10, it is possible to determine the deterioration of the sealing material 141 or 142, which cannot be determined only by the number of times the piston 17 is driven. Therefore, the maintenance of the sealing material 141 or 142 is appropriately managed.

[0120] (Other embodiments)

[0121] Other embodiments of the gas chromatograph 1 and the liquid sampling valve 10 will be described below.

[0122] <Prediction of maintenance time based on changes in driver data>

[0123] In the liquid sampling valve 10, the wear of the sealing material 141 or 142 increases as the number of actuations of the piston 17 increases. The more the sealing material 141 or 142 wears, the faster the piston 17 moves. The more the sealing material 141 or 142 wears, the smaller the strain on the sealing material 141 or 142. In other words, the number of actuations of the piston 17 is correlated with actuation data such as the movement speed of the piston 17 and the strain on the sealing material 141 or 142.

[0124] For example, Figure 10 A graph showing the correlation between the number of times the piston 17 is driven and the moving speed of the piston 17 is shown. Figure 10 In the graph, the horizontal axis represents the number of actuations. The vertical axis represents the movement speed of piston 17. Actual measurement data of the movement speed of piston 17 obtained for liquid sampling valve 10 is represented by solid circles. It can be seen that the movement speed of piston 17 increases with the number of actuations.

[0125] The relationship between the number of times the piston 17 is driven and the moving speed of the piston 17 can be formulated, for example, by linear approximation. Figure 10 In the graph of the movement speed of piston 17, the dashed line represents extrapolated data that is a linear approximation of the measured data for the movement speed of piston 17. The extrapolated data for the movement speed of piston 17 extends the relationship between the number of times piston 17 is driven and the movement speed of piston 17 to a range where piston 17 has not actually been driven. This extrapolated data is used to predict the movement speed of piston 17 assuming that the number of times piston 17 is driven increases. By generating the extrapolated data based on the measured data for the movement speed of piston 17, controller 40 of gas chromatograph 1 can predict the movement speed of piston 17 if the number of times piston 17 is driven is set to a number that has not actually been reached.

[0126] Using the extrapolated data of the movement speed of the piston 17, the controller 40 is able to predict the number of times the piston 17 is driven when the predicted value of the movement speed of the piston 17 will be equal to or greater than the second retightening threshold value or the second replacement threshold value, as a predicted maintenance time when maintenance such as retightening the nut 12 or replacing the sealing materials 141 and 142 is required. Figure 10In the graph, the threshold value of the movement speed of piston 17 is represented by a horizontal dashed line. The maintenance time is represented by a vertical dashed line. When controller 40 drives piston 17 at a constant cycle, controller 40 can calculate the date and time when the maintenance time will be reached by multiplying the number of times piston 17 is driven until the maintenance time is reached by the drive cycle of piston 17.

[0127] The number of times the piston 17 is actuated is also related to the strain on the sealing material 141 or 142. The controller 40 can generate extrapolated data by approximating the measured data of the strain of the sealing material 141 or 142 relative to the number of times the piston 17 is actuated. The extrapolated data of the strain of the sealing material 141 or 142 extends the relationship between the number of times the piston 17 is actuated and the strain of the sealing material 141 or 142 to a range of times the piston 17 has not actually been actuated, and the extrapolated data is used to predict the strain of the sealing material 141 or 142 assuming that the number of times the piston 17 is actuated increases. By generating the extrapolated data based on the measured data of the strain of the sealing material 141 or 142, the controller 40 can predict the strain of the sealing material 141 or 142 when the number of times the piston 17 is actuated is set to a number that has not actually been reached.

[0128] Using the extrapolated data of the strain of the sealing materials 141 and 142, the controller 40 is able to predict the number of drives of the piston 17 when the predicted value of the strain of the sealing materials 141 and 142 will be equal to or greater than the third retightening threshold or the third replacement threshold, as the predicted maintenance time when maintenance such as retightening the nut 12 or replacing the sealing materials 141 and 142 is required.

[0129] The controller 40 is not limited to performing linear approximation, but may perform various other approximations, such as polynomial approximation, to generate extrapolated data of the driving data.

[0130] As described above, the controller 40 is capable of predicting maintenance timing based on the prediction of drive data. The predicted maintenance timing may also be referred to as predicted maintenance time. The user can determine when to replace the sealing materials 141 and 142 based on the predicted maintenance time, thereby being able to replace the sealing materials 141 and 142 in a planned manner. In addition, the user is also able to plan to retighten the nut 12 based on the predicted maintenance time. Therefore, the user can develop a plan to incorporate the maintenance work of the liquid sampling valve 10 into the analysis work using the gas chromatograph 1, and implement the plan. The operation of predicting maintenance timing may also be referred to as a maintenance time prediction step. The operation of predicting when to replace the sealing materials 141 and 142 may also be referred to as a replacement time prediction step. The operation of predicting when to retighten the nut 12 may also be referred to as a retightening time prediction step.

[0131] <Other Methods of Calculating the Moving Speed ​​of the Piston 17>

[0132] According to the above embodiment, the moving speed of the piston 17 is calculated based on the acceleration measured by the accelerometer 171 attached to the piston 17. Another method of calculating the moving speed of the piston 17 will be described below.

[0133] like Figure 11 As shown, the accelerometer 171 may be attached to the cylinder 18 instead of the piston 17. The controller 40 of the gas chromatograph 1 may be communicatively connected to the accelerometer 171 via a cable 172. The controller 40 may be communicatively connected to the accelerometer 171 wirelessly.

[0134] When piston 17 moves in a direction that pushes rod 15 from sampling chamber 152 toward vaporization chamber 161, piston 17 moves until it strikes the wall of cylinder 18 on the side closer to sampling chamber 152. Conversely, when piston 17 moves in a direction that pulls rod 15 from vaporization chamber 161 toward sampling chamber 152, piston 17 moves until it strikes the wall of cylinder 18 on the side farther from sampling chamber 152. An accelerometer 171 attached to cylinder 18 detects the acceleration generated within cylinder 18 when piston 17 strikes the wall of cylinder 18.

[0135] The control unit 40 of the gas chromatograph 1 obtains the time when the accelerometer 171 detects acceleration as the time when the piston 17 strikes the wall of the cylinder 18. The control unit 40 calculates the time from the time when driving air is supplied to the driving air supply unit 181 or 182 to start driving the piston 17 to the time when the piston 17 strikes the wall of the cylinder 18 as the movement time of the piston 17. The control unit 40 obtains known information about the distance moved by the piston 17 within the cylinder 18 and divides the movement distance of the piston 17 by the movement time to calculate the movement speed of the piston 17.

[0136] By attaching the accelerometer 171 to the cylinder 18 , allowing the velocity of the piston 17 to be easily calculated, it can be easily added to the liquid sampling valve 10 when the necessary configuration to calculate the velocity of movement of the piston 17 is already in place.

[0137] like Figure 12 As shown, a proximity sensor 173 or 175 may be attached to the cylinder 18. The proximity sensor 175 may be attached to the wall of the cylinder 18 on the side close to the sampling chamber 152. The proximity sensor 173 may be attached to the wall of the cylinder 18 on the side away from the sampling chamber 152. The controller 40 of the gas chromatograph 1 may be communicatively connected to the proximity sensor 173 via a cable 174. The controller 40 may be communicatively connected to the proximity sensor 175 via a cable 176. The controller 40 may be communicatively connected to the proximity sensor 173 or 175 wirelessly.

[0138] When piston 17 moves in a direction that pushes rod 15 from sampling chamber 152 toward vaporization chamber 161, piston 17 moves until it strikes the wall of cylinder 18 on the side close to sampling chamber 152. Proximity sensor 175 detects when piston 17 strikes the wall of cylinder 18 on the side close to sampling chamber 152. Conversely, when piston 17 moves in a direction that pulls rod 15 from vaporization chamber 161 toward sampling chamber 152, piston 17 moves until it strikes the wall of cylinder 18 on the side away from sampling chamber 152. Proximity sensor 173 detects when piston 17 strikes the wall of cylinder 18 on the side away from sampling chamber 152.

[0139] The controller 40 of the gas chromatograph 1 obtains the time when the proximity sensor 173 or 175 detects that the piston 17 has struck the wall of the cylinder 18 as the time when the piston 17 has struck the wall of the cylinder 18. The controller 40 calculates the time from the time when the driving air is supplied to the driving air supply unit 181 or 182 to start driving the piston 17 to the time when the piston 17 strikes the wall of the cylinder 18 as the movement time of the piston 17. The controller 40 obtains known information about the distance the piston 17 has moved in the cylinder 18 and divides the distance moved by the movement time to calculate the movement speed of the piston 17.

[0140] By being able to calculate the moving speed of the piston 17 using the proximity sensor 173 or 175 , the moving speed of the piston 17 can be calculated with a simple or inexpensive configuration.

[0141] <Determination Considering Pressure Fluctuation of Driving Air>

[0142] The controller 40 of the gas chromatograph 1 can determine the need to replace the sealing material 141 or 142 by comparing the movement speed of the piston 17 with a second replacement threshold, assuming that the pressure of the driving air supplied from the driving air supply 181 or 182 to the cylinder 18 is constant. As the pressure of the driving air changes, the controller 40 can change the second replacement threshold based on the driving air pressure. For example, the higher the driving air pressure, the faster the movement speed of the piston 17. Therefore, the higher the driving air pressure, the larger the second replacement threshold can be. The higher the driving air pressure, the larger the third replacement threshold, which is used to compare the strain of the sealing material 141 or 142, can be.

[0143] The controller 40 may change the second re-tightening threshold value for determining the necessity of re-tightening the nut 12 according to the pressure of the driving air. For example, the higher the pressure of the driving air, the larger the second re-tightening threshold value may be. The higher the pressure of the driving air, the larger the third re-tightening threshold value may be.

[0144] The controller 40 may correct the driving data based on the pressure of the driving air. For example, when the driving air pressure is higher than a reference pressure, the controller 40 may calculate a correction value for the speed of the piston 17 when the driving air pressure is at the reference pressure based on the measured speed of the piston 17 and the driving air pressure, and compare this correction value with a second replacement threshold or a second retightening threshold. Furthermore, when the driving air pressure is higher than the reference pressure, the controller 40 may calculate a correction value for the strain of the sealing material 141 or 142 when the driving air pressure is at the reference pressure based on the measured strain of the sealing material 141 or 142 and the driving air pressure, and compare this correction value with a third replacement threshold or a third retightening threshold.

[0145] As described above, the controller 40 can determine the reference in accordance with the pressure change of the driving air. When the pressure of the driving air is taken into consideration, the accuracy of determining the necessity of maintenance is improved.

[0146] <Other aspects of maintenance management>

[0147] As described above, the maintenance management method for determining whether to output an alarm regarding maintenance of the liquid sampling valve 10 is described as being executed by the controller 40 of the gas chromatograph 1. The liquid sampling valve 10 may include a processor that implements the maintenance management method for the liquid sampling valve 10. In other words, the maintenance management method or maintenance management program described above may be executed by the processor of the liquid sampling valve 10, rather than solely by the controller 40 of the gas chromatograph 1.

[0148] The gas chromatograph 1 may include a maintenance management device for executing the maintenance management method for the liquid sampling valve 10. The maintenance management device may be different from the controller 40 and the processor of the liquid sampling valve 10. When the controller 40 of the gas chromatograph 1 or the processor of the liquid sampling valve 10 has the function of executing the maintenance management method, each may also be referred to as a maintenance management device.

[0149] The above description of the embodiment according to the present disclosure is provided with reference to the accompanying drawings. The specific configuration is not limited to the described embodiment, and various modifications are also included without departing from the scope of the present disclosure.

[0150] Reference Signs List

[0151] 1: Gas chromatograph (20: column, 30: detector, 40: controller)

[0152] 10: Liquid sampling valve

[0153] 11 blocks: (111: heater, 112: temperature sensor, 113: carrier gas channel, 114, 115: inner wall)

[0154] 12: Nut

[0155] 131, 132: Piping

[0156] 133: Liquid sample block

[0157] 141, 142: Sealing material (141a, 142a: Inner wall)

[0158] 143: Strain sensor

[0159] 144: Cable

[0160] 15: rod (151: sampling slot, 153: liquid sample)

[0161] 152: Sampling Room

[0162] 16: Piping

[0163] 161: Vaporization Chamber

[0164] 17: Pistons

[0165] 171: Accelerometer

[0166] 173, 175: Proximity sensor

[0167] 172, 174, 176: Cable

[0168] 18: Cylinder (181, 182: driving air supply unit)

Claims

1. A maintenance and management method for a liquid sampling valve, comprising: a housing comprising a sampling chamber and a vaporization chamber, wherein a liquid sample flows through the sampling chamber and the liquid sample is vaporized in the vaporization chamber; a sealing material separating the sampling chamber from the vaporization chamber; a rod configured to be able to enter and exit the vaporization chamber through the hole in the sealing material; and A piston is configured to drive the rod, and the maintenance management method includes: A step of obtaining the number of actuations: obtaining the number of times the piston has been actuated after the sealing material is newly installed; and A replacement determining step of determining that the sealing material needs to be replaced when the number of times the piston has been driven is equal to or greater than a first replacement threshold value, regardless of the time that has passed since the sealing material was newly installed.

2. The maintenance management method according to claim 1, further comprising a drive data acquisition step of acquiring at least one of the moving speed of the piston or the strain of the sealing material, wherein In the replacement determination step, determining that the sealing material needs to be replaced also occurs in at least one of the following situations: when the movement speed of the piston is equal to or greater than a second replacement threshold, or when the strain of the sealing material is equal to or less than a third replacement threshold.

3. The maintenance management method according to claim 2 further includes a replacement time prediction step: generating extrapolated data that predicts the relationship between the number of times the piston has been driven and the moving speed of the piston or the strain of the sealing material, and calculating at least one of the following two items as the predicted maintenance time until the sealing material needs to be replaced: (i) the number of times the piston is driven when the moving speed of the piston in the extrapolated data is equal to or greater than the second replacement threshold; or (ii) the number of times the piston is driven when the strain of the sealing material in the extrapolated data is equal to or less than the third replacement threshold.

4. The maintenance management method according to any one of claims 1 to 3 further includes a retightening determination step before the replacement determination step: when the number of times the piston has been driven is equal to or greater than a first retightening threshold, regardless of the time that has passed after the sealing material is newly installed, it is determined that the nut that applies a load to the sealing material needs to be retightened.

5. The maintenance management method according to claim 4, wherein: In the replacement determination step, when retightening of the nut has been performed a prescribed number of times or more, determination is also made that the sealing material needs to be replaced.

6. A maintenance management device comprising: A processor configured to execute the maintenance management method according to any one of claims 1 to 3.

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