JP4933305B2 - Pressure guiding tube clogging detection apparatus and pressure guiding tube clogging detection method - Google Patents

Description

 The present invention relates to a pressure guiding tube clogging detecting apparatus and a pressure guiding tube clogging detecting method for detecting clogging of a pressure guiding tube, in particular, clogging of a pressure guiding tube in a differential pressure transmitter for measuring a differential pressure of a fluid flowing in a pipe line.

  As is well known, a differential pressure transmitter is a pressure guiding pipe arranged in the upstream and downstream of the orifice, by providing the differential pressure between the upstream (high pressure side) and the downstream (low pressure side) of the orifice provided in the fluid piping. It measures based on the pressure transmitted through this. In such a differential pressure transmitter, when the pressure guiding tube is clogged, it is difficult to accurately measure the differential pressure. Therefore, detecting clogging of the pressure guiding tube is very important from the viewpoint of fluid management. Hereinafter, an example of a conventional method for detecting clogging of a pressure guiding tube will be described.

 When the differential pressure data obtained in time series from the differential pressure transmitter is Dps (i) under normal conditions (that is, the pressure guiding tube is not clogged), the differential pressure fluctuation Fdps (i) is expressed by the following equation (1). It is represented by In the following equation (1), Dps (i) is the current value of the differential pressure data, and Dps (i-1) is the previous value of the differential pressure data. On the other hand, the variance (root mean square value) Vas of the differential pressure fluctuation Fdps (i) is expressed by the following equation (2). N is the total number of samples of the differential pressure data Dps (i). Hereinafter, this Vas is referred to as reference fluctuation dispersion. The reference fluctuation dispersion Vas in such a normal state is obtained in advance at the first stage of actual operation.

 Next, in the actual operation of the plant, every time when the pressure guiding tube diagnosis time comes, the differential pressure fluctuation is obtained in the same manner as described above by using the differential pressure data Dp (i) obtained in time series from the differential pressure transmitter. Dynamic Fdp (i) and differential pressure fluctuation variance Va are obtained. The calculation formulas of the differential pressure fluctuation Fdp (i) and the variance Va of the differential pressure fluctuation during actual operation are the same as the above formulas (1) and (2).

 Then, a ratio D = √ (Va / Vas) between the variance Va of the differential pressure fluctuation obtained at the time of diagnosis of the pressure guiding tube and the reference fluctuation dispersion Vas obtained in advance as described above is calculated. . Since the dispersion Va of the differential pressure fluctuation changes according to the clogged state of the pressure guiding tube, the clogging of the pressure guiding tube can be detected by the change in the ratio D. For example, when both the high-pressure side and the low-pressure side pressure guiding tube are clogged, the variance Va of the differential pressure fluctuation is small (the ratio D is also small). In addition, when one of the high pressure side or low pressure side pressure guiding tubes is clogged, the variance Va of the differential pressure fluctuation increases (the ratio D also increases). Further, when the pressure guiding tube is normal, the differential pressure fluctuation dispersion Va is close to the reference fluctuation dispersion Vas, and thus the ratio D is close to “1”. Therefore, by comparing the ratio D with a predetermined threshold value, it can be determined whether both the high-pressure side and the low-pressure side pressure guiding tube are clogged, one of them is clogged, or normal.

When obtaining the differential pressure fluctuation, the above equation (3) may be used instead of the above equation (1). For example, when the equation (1) is used, when a transient change (increase or decrease) occurs in the differential pressure, the transient change component appears as oscillation. Therefore, by using the expression (3), even if a transient change occurs in the differential pressure as described above, the transient change component can be removed, and only the true oscillation component is obtained. (See Patent Document 2 below).
JP 2004-132817 A JP 2004-294175 A

  By the way, the dispersion of the differential pressure fluctuation not only changes according to the clogged state of the pressure guiding tube, but also changes due to the influence of the fluid flow rate. Accordingly, since the reference fluctuation dispersion Vas is an experimental value under a certain flow rate condition, when the flow rate increases or decreases during actual operation, the value of the ratio D changes even if the pressure guiding tube is clogged. End up. That is, it is necessary to change the set value of the threshold value or the reference fluctuation dispersion Vas in accordance with the flow rate of the fluid, which increases the operator's work load. For example, the change of the set value as described above is automated. In this case, there has been a problem that the cost of the apparatus is increased.

  The present invention has been made in view of such circumstances, and an object thereof is to accurately detect the clogged state of a pressure guiding tube without being affected by the flow rate of a fluid.

In order to solve the above-mentioned problem, in the present invention, as a first solving means related to a pressure guiding tube clogging detection apparatus, a high pressure side pressure transmitted through a high pressure side pressure guiding tube and a low pressure side pressure guiding tube are transmitted. A differential pressure detecting means for detecting a differential pressure of the fluid based on the low-pressure side pressure and outputting time-series data of the differential pressure; and a difference for calculating a differential pressure fluctuation based on the time-series data of the differential pressure Pressure fluctuation calculating means;
The fluctuation dispersion calculating means for calculating the dispersion of the differential pressure fluctuation, the dispersion of the differential pressure fluctuation calculated by the fluctuation dispersion calculating means, and the difference obtained in advance when the high pressure side pressure guiding tube and the low pressure side pressure guiding tube are normal. Based on dispersion ratio calculation means for calculating a dispersion ratio with respect to dispersion of pressure fluctuation, differential pressure time series data output from the differential pressure detection means, and differential pressure time series data obtained in advance during normal operation Calculating a correction value for suppressing a change in the dispersion ratio caused by a change in the flow rate of the fluid, and correcting the dispersion ratio by the correction value; and the correction corrected by the dispersion ratio correction means And clogging determining means for determining clogging of the high-pressure side pressure guiding tube and the low-pressure side pressure guiding tube based on a dispersion ratio.

 In the present invention, as the second solving means relating to the pressure guiding tube blockage detecting device, in the first solving means, the dispersion ratio correcting means is an average value of time series data of the differential pressure obtained in advance at the normal time. The ratio Adps / Adp between Adps and the average value Adp of the time series data of the differential pressure output from the differential pressure detecting means is calculated as a correction value, and the dispersion ratio is multiplied by the dispersion ratio. It is characterized by correcting.

 In the present invention, as a third solving means relating to the pressure guiding tube blockage detecting device, in the first or second solving means, the differential pressure detecting means compares the detected differential pressure with a predetermined threshold value. The time-series data of the differential pressure larger than the threshold is output, and the time-series data of the differential pressure obtained in advance at the normal time is a value larger than the predetermined threshold, and the differential pressure fluctuation obtained in advance at the normal time. The dispersion of the motion is calculated based on time-series data of a differential pressure larger than the predetermined threshold obtained in advance at the normal time.

 In the present invention, as the fourth solving means related to the pressure guiding tube blockage detecting device, in any one of the first to third solving means, the differential pressure fluctuation calculating means includes the time series data of the differential pressure. The differential pressure using one of the following formulas (11), (12) or (13) consisting of the current value Dp (i), the previous value Dp (i-1), and the previous value Dp (i-2) The fluctuation Fdp (i) is calculated.

 On the other hand, in the present invention, as a first solving means related to the pressure guiding tube clogging detection method, the high pressure side pressure transmitted through the high pressure side pressure guiding tube and the low pressure side pressure transmitted through the low pressure side pressure guiding tube. A first step of detecting a differential pressure of the fluid on the basis of the fluid pressure and acquiring time-series data of the differential pressure; a second step of calculating a differential pressure fluctuation based on the time-series data of the differential pressure; and the differential pressure A third step for calculating the dispersion of the oscillation, a variance of the differential pressure oscillation calculated in the third step, and a variance of the differential pressure oscillation obtained in advance when the high-pressure side impulse line and the low-pressure side impulse line are normal. The flow rate change of the fluid based on the fourth step of calculating the dispersion ratio, the time-series data of the differential pressure obtained in the first step, and the time-series data of the differential pressure obtained in advance at the normal time Calculating a correction value for suppressing a change in the dispersion ratio caused by A step of correcting the dispersion ratio based on the correction value, and a step of determining clogging of the high-pressure side pressure guiding tube and the low-pressure side pressure guiding tube based on the dispersion ratio corrected by the sixth step. And 7 steps.

 According to the present invention, a correction value that suppresses a change in the dispersion ratio due to a change in the flow rate of the fluid is obtained, and the dispersion ratio is corrected by the correction value, so that it is accurate without being affected by the fluid flow rate. In addition, it is possible to detect the clogged state of the pressure guiding tube.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic configuration diagram of a pressure guiding tube clogging detection apparatus according to the first embodiment. This pressure guiding tube clogging detection apparatus is composed of a high pressure side pressure guiding tube 3 and a low pressure side guiding tube disposed in a front stage (high pressure side) and a rear stage (low pressure side) of an orifice 2 provided in a fluid pipe 1 of a plant or the like. The clogging of the pressure tube 4 is detected.

 As shown in FIG. 1, the pressure guiding tube clogging detection apparatus includes a differential pressure transmitter (differential pressure detection means) 5, a differential pressure fluctuation calculation section 6, a fluctuation dispersion calculation section 7, a dispersion ratio calculation section 8, a dispersion ratio. The correction unit 9 includes a clogging determination unit 10, a display unit 11, and a storage unit 12.

 The differential pressure transmitter 5 detects the differential pressure of the fluid based on the high pressure side pressure transmitted through the high pressure side pressure guiding tube 3 and the low pressure side pressure transmitted through the low pressure side pressure guiding tube 4, Differential pressure data Dp (i), which is time-series data indicating the differential pressure, is output to the differential pressure fluctuation calculating unit 6 and the dispersion ratio correcting unit 9. The differential pressure fluctuation calculation unit 6 calculates the differential pressure fluctuation Fdp (i) from the following equation (4) based on the differential pressure data Dp (i) obtained from the differential pressure transmitter 5 in time series. The differential pressure fluctuation Fdp (i) is output to the fluctuation dispersion calculating unit 7. In the following equation (4), Dp (i) is the current value of the differential pressure data, and Dp (i-1) is the previous value of the differential pressure data.

 The fluctuation dispersion calculation unit 7 calculates the variance Va (root mean square value) of the differential pressure fluctuation Fdp (i) obtained from the differential pressure fluctuation calculation unit 6 based on the following equation (5), and the difference The pressure fluctuation dispersion Va is output to the dispersion ratio calculation unit 8. N is the total number of samples of the differential pressure data Dp (i). The dispersion ratio calculation unit 8 is configured so that the differential pressure fluctuation dispersion Va obtained from the fluctuation dispersion calculation unit 7 and the high pressure side pressure guiding pipe 3 and the low pressure side pressure guiding pipe 4 stored in advance in the storage unit 12 are normal. The dispersion ratio D with respect to the reference fluctuation dispersion Vas is calculated from the following equation (6), and the dispersion ratio D is output to the dispersion ratio correction unit 9.

 The dispersion ratio correction unit 9 calculates the differential pressure data average value Adp from the following equation (7) based on the differential pressure data Dp (i) obtained from the differential pressure transmitter 5 in time series, while the storage unit 12 The differential pressure data average value (reference differential pressure average value) Adps when the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are normal, and the differential pressure data average value Adp calculated as described above are stored in advance. Is calculated as a correction value k (= Adps / Adp). The correction value k is a correction value for suppressing a change in the dispersion ratio D caused by a change in the flow rate of the fluid flowing through the pipe 1. The dispersion ratio correction unit 9 calculates the corrected dispersion ratio Dcomp by multiplying the dispersion ratio D obtained from the dispersion ratio correction unit 9 by the correction value k as shown in the following equation (8), and the corrected dispersion ratio Dcomp is output to the clogging determination unit 10.

 The clogging determination unit 10 determines the clogged state of the high pressure side pressure guiding tube and the low pressure side pressure guiding tube by comparing the corrected dispersion ratio Dcomp and a predetermined threshold value, and outputs the determination result to the display unit 11. The display unit 11 is a liquid crystal display device, for example, and displays the determination result by the clogging determination unit 10. The storage unit 12 stores in advance the reference fluctuation dispersion Vas and the reference differential pressure average value Adps when the high-pressure side impulse line 3 and the low-pressure side impulse line 4 are normal.

Next, the operation of the pressure guiding tube clogging detection apparatus configured as described above will be described.
<Setting of reference fluctuation dispersion Vas and reference differential pressure average value Adps>
First, when the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are normal (that is, the pressure guiding tube is not clogged), based on the differential pressure data obtained from the differential pressure transmitter 5 in time series, the reference oscillation is performed. The variance Vas and the reference differential pressure average value Adps must be obtained in advance in the first stage of actual operation and stored in the storage unit 12. Specifically, when the differential pressure data obtained in time series from the differential pressure transmitter 5 under normal conditions and a constant flow rate is Dps (i), the differential pressure fluctuation Fdps (i) is the above (1). It is expressed by a formula. On the other hand, the dispersion (reference fluctuation dispersion) Vas of the differential pressure fluctuation Fdps (i) is expressed by the above equation (2). The reference differential pressure average value Adps is represented by the following equation (9). Based on these equations (1), (2), and (9), the reference fluctuation dispersion Vas and the reference differential pressure average value Adps are obtained and stored in the storage unit 12 in advance.

<Clogging judgment operation during actual operation>
FIG. 2 is a flowchart of the pressure guiding tube clogging determining operation during the actual operation of the plant. In addition, the operation | movement flow shown in FIG. 2 is performed whenever the diagnosis time of a pressure guiding tube comes. First, the differential pressure transmitter 5 detects the differential pressure of the fluid based on the high pressure side pressure transmitted through the high pressure side pressure guiding tube 3 and the low pressure side pressure transmitted through the low pressure side pressure guiding tube 4. Then, the differential pressure data Dp (i) indicating the differential pressure is output to the differential pressure fluctuation calculating unit 6 and the dispersion ratio correcting unit 9 (step S1). Then, the differential pressure fluctuation calculation unit 6 calculates the differential pressure fluctuation Fdp (i) from the above equation (4) based on the differential pressure data Dp (i) obtained from the differential pressure transmitter 5 in time series. The differential pressure fluctuation Fdp (i) is calculated and outputted to the fluctuation dispersion calculating section 7 (step S2).

 Next, the fluctuation dispersion calculating unit 7 calculates the variance Va of the differential pressure fluctuation Fdp (i) obtained from the differential pressure fluctuation calculating unit 6 based on the following equation (5), and the differential pressure fluctuation is calculated. The variance Va is output to the variance ratio calculation unit 8 (step S3). Then, the dispersion ratio calculation unit 8 is configured so that the differential pressure fluctuation dispersion Va obtained from the fluctuation dispersion calculation unit 7 and the normality of the high-pressure side impulse line 3 and the low-pressure side impulse line 4 stored in the storage unit 12 in advance. The dispersion ratio D with respect to the reference fluctuation dispersion Vas at the time is calculated from the above equation (6), and the dispersion ratio D is output to the dispersion ratio correction unit 9 (step S4).

 Subsequently, the dispersion ratio correction unit 9 calculates the differential pressure data average value Adp from the above equation (7) based on the differential pressure data Dp (i) obtained from the differential pressure transmitter 5 in time series (step) S5). Then, the dispersion ratio correction unit 9 stores the reference differential pressure average value Adps and the differential pressure data average value Adp when the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are normal stored in the storage unit 12 in advance. The ratio is calculated as a correction value k (= Adps / Adp) (step S6). Furthermore, the dispersion ratio correction unit 9 calculates the corrected dispersion ratio Dcomp by multiplying the dispersion ratio D obtained from the dispersion ratio correction unit 9 by the correction value k as shown in the above equation (8), and the correction The dispersion ratio Dcomp is output to the clogging determination unit 10 (step S7).

 By the way, as described above, the dispersion of the differential pressure fluctuation not only changes according to the clogged state of the pressure guiding tube but also changes due to the influence of the flow rate of the fluid. For example, when the flow rate increases, the differential pressure fluctuation dispersion Va increases, and the dispersion ratio D also increases. On the other hand, when the flow rate increases, the differential pressure increases, that is, the differential pressure data average value Adp also increases, so the correction value k decreases. Thus, the correction value k is a value that suppresses a change in the dispersion ratio D caused by a change in the flow rate of the fluid flowing through the pipe 1. Therefore, the corrected dispersion ratio Dcomp obtained from the equation (8) is a value in which the influence of the flow rate change on the dispersion ratio D is corrected.

 Next, the clogging determination unit 10 determines the clogged state of the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 by comparing the corrected dispersion ratio Dcomp and a predetermined threshold value, and displays the determination result on the display unit 11. (Step S8). Since the determination method is the same as that of the prior art, a detailed description thereof will be omitted. However, for example, the corrected dispersion ratio Dcomp is compared with the first threshold (for example, 3) and the second threshold (for example, 0.3). When the corrected dispersion ratio Dcomp ≧ first threshold value, it is determined that one of the high pressure side pressure guiding tube 3 or the low pressure side pressure guiding tube 4 is clogged, and when the corrected dispersion ratio Dcomp ≦ second threshold value, It is determined that both the pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are clogged, and when the second threshold value <corrected dispersion ratio Dcomp <the first threshold value, it is determined as normal. The display unit 11 displays the clogged state of the high-pressure side pressure guiding tube 3 and the low-pressure side pressure guiding tube 4 based on the clogging determination result by the clogging determining unit 10.

  As described above, according to the pressure guiding tube blockage detecting device of the first embodiment, the correction value k that suppresses the change in the dispersion ratio D caused by the change in the flow rate of the fluid flowing through the pipe 1 is obtained, and the correction value By correcting the dispersion ratio D by k, it is possible to accurately detect the clogged state of the pressure guiding tube without being affected by the flow rate of the fluid. Therefore, it is not necessary to change the set value of the threshold value or the reference fluctuation dispersion Vas in accordance with the flow rate of the fluid. Therefore, it is necessary to prevent an increase in the operator's work load and to automate the change of the set value as described above. Therefore, an increase in device cost can be prevented.

  In the first embodiment, as the correction value k, the ratio between the reference differential pressure average value Adps when the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are normal and the differential pressure data average value Adp during diagnosis ( = Adps / Adp), but is not limited to this. For example, the total value Tdps of the differential pressure data Dps (i) of the predetermined number of samples obtained in the same way at normal time and the time in actual operation (during diagnosis) A ratio (= Tdps / Tdp) with the total value Tdp of the differential pressure data Dp (i) of a predetermined number of samples obtained in series may be obtained as the correction value k.

  As described above, in the pressure guiding tube blockage detecting device according to the first embodiment, the ratio between the reference differential pressure average value Adps previously obtained during normal operation and the differential pressure data average value Adp obtained during diagnosis is a correction value. By using k (= Adps / Adp) and using this correction value k, the change in the dispersion ratio D due to the flow rate change was corrected. However, in a general plant, the differential pressure data Dp (i) is not always constant during diagnosis. For example, even during a single diagnosis, the flow rate may vary from zero to several times the average flow rate value, or the fluid may flow intermittently depending on the plant.

FIG. 3 shows the time change of the differential pressure data Dp (i) under the condition that the fluid flows intermittently (hereinafter referred to as the intermittent flow condition). FIG. 3 illustrates a case where fluid does not flow in the periods T1 and T2 (that is, the flow rate is zero) and the differential pressure data Dp (i) is zero.
Under such intermittent flow conditions, the differential pressure fluctuation dispersion Va and the differential pressure are sampled because the differential pressure data Dp (i) is sampled during the periods T1 and T2 in which no fluid flows and the periods in which other fluids flow. An error occurs in the calculation of the data average value Adp. For example, when the sampling number in the periods T1 and T2 in which the fluid does not flow is n and the sampling number in the period in which the other fluid flows is m, the pressure guiding tube clogging detection apparatus of the first embodiment is used under intermittent flow conditions. In this case, the corrected dispersion ratio Dcomp is expressed by the following equation (10). As can be seen from this equation (10), the dispersion ratio D tends to be overcorrected as the differential pressure fluctuation dispersion Va decreases under intermittent flow conditions.

  As described above, when the flow rate changes drastically as in an intermittent flow condition, it is difficult to accurately detect the clogged state of the pressure guiding tube. In such a case, the clogged state of the pressure guiding tube can be accurately detected by using the pressure guiding tube clogging detection device of the second embodiment described below.

[Second Embodiment]
As for the device configuration of the pressure guiding tube clogging detecting device in the second embodiment, the following functions are added to the differential pressure transmitter 5 as compared with the pressure guiding tube clogging detecting device of the first embodiment shown in FIG. Since other components are the same, illustration and description are omitted. For convenience of explanation, in order to distinguish from the differential pressure transmitter 5 of the first embodiment, the differential pressure transmitter 5a is used in the second embodiment.

  The differential pressure transmitter 5 a of the pressure guiding tube clogging detection device in the second embodiment is configured to convert the high pressure side pressure transmitted through the high pressure side pressure guiding tube 3 and the low pressure side pressure transmitted through the low pressure side pressure guiding tube 4. Based on this, the differential pressure of the fluid is detected, the differential pressure is compared with a predetermined threshold LT, and only the differential pressure data Dp (i), which is time series data of the differential pressure greater than the threshold LT, is calculated. 6 and the dispersion ratio correction unit 9. Here, the threshold value LT is set to about 5% of the value of the average differential pressure data Dp (i).

Next, the operation of the pressure guiding tube blockage detection device in the second embodiment will be described.
<Setting of reference fluctuation dispersion Vas and reference differential pressure average value Adps>
First, as in the first embodiment, when the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are normal (that is, the pressure guiding tube is not clogged), the differential pressure obtained in time series from the differential pressure transmitter 5a. Based on the data Dp (i), the reference fluctuation dispersion Vas and the reference differential pressure average value Adps must be obtained in advance in the first stage of actual operation and stored in the storage unit 12. Here, the difference from the first embodiment is that the differential pressure data Dp (i) obtained in time series from the differential pressure transmitter 5a is the differential pressure data Dp () having a value larger than the threshold LT as described above. i). That is, as is apparent from FIG. 3, the differential pressure transmitter 5a obtains differential pressure data Dp (i) only during a period during which fluid other than the periods T1 and T2 during which no fluid flows.

 Specifically, when the differential pressure data larger than the threshold value LT obtained in time series from the differential pressure transmitter 5a under the intermittent flow conditions as shown in FIG. The pressure fluctuation Fdps (i) is calculated by the above equation (1). On the other hand, the dispersion (reference fluctuation dispersion) Vas of the differential pressure fluctuation Fdps (i) is calculated by the above equation (2). In Equation (2), N is the total number of samples of the differential pressure data Dps (i), but this total number of samples is naturally the number of differential pressure data Dps (i) greater than the threshold LT. The reference differential pressure average value Adps is calculated by the above equation (9). Based on these equations (1), (2), and (9), the reference fluctuation dispersion Vas and the reference differential pressure average value Adps are obtained and stored in the storage unit 12 in advance.

<Clogging judgment operation during actual operation>
FIG. 4 is a flowchart of the pressure guiding tube blockage determining operation during actual operation (under intermittent flow conditions) of the plant in the second embodiment. In addition, the operation | movement flow shown in FIG. 4 is performed whenever the diagnosis time of a pressure guiding tube comes. First, the differential pressure transmitter 5 a detects the differential pressure of the fluid based on the high pressure side pressure transmitted through the high pressure side pressure guiding tube 3 and the low pressure side pressure transmitted through the low pressure side pressure guiding tube 4. The differential pressure is compared with the threshold LT, and only the differential pressure data Dp (i), which is time-series data of the differential pressure larger than the threshold LT, is output to the differential pressure fluctuation calculating unit 6 and the dispersion ratio correcting unit 9 ( Step S10). In this case, the differential pressure transmitter 5a outputs differential pressure data Dp (i) only during a period in which a fluid other than the periods T1 and T2 in which no fluid flows.

  Then, the differential pressure fluctuation calculation unit 6 calculates the differential pressure fluctuation from the equation (4) based on the differential pressure data Dp (i) larger than the threshold value LT obtained in time series from the differential pressure transmitter 5. Fdp (i) is calculated, and the differential pressure fluctuation Fdp (i) is output to the fluctuation dispersion calculating unit 7 (step S11).

 Next, the fluctuation dispersion calculator 7 calculates the variance Va of the differential pressure fluctuation Fdp (i) obtained from the differential pressure fluctuation calculator 6 based on the above equation (5), and the differential pressure fluctuation is calculated. The variance Va is output to the variance ratio calculation unit 8 (step S12). Then, the dispersion ratio calculation unit 8 is configured so that the differential pressure fluctuation dispersion Va obtained from the fluctuation dispersion calculation unit 7 and the normality of the high-pressure side impulse line 3 and the low-pressure side impulse line 4 stored in the storage unit 12 in advance. The dispersion ratio D with respect to the reference fluctuation dispersion Vas at the time is calculated from the above equation (6), and the dispersion ratio D is output to the dispersion ratio correction unit 9 (step S13).

 Subsequently, the dispersion ratio correction unit 9 calculates the differential pressure data average value Adp from the above equation (7) based on the differential pressure data Dp (i) larger than the threshold value LT obtained in time series from the differential pressure transmitter 5a. Is calculated (step S14). Then, the dispersion ratio correction unit 9 stores the reference differential pressure average value Adps when the high pressure side pressure guiding tube 3 and the low pressure side pressure guiding tube 4 are normal and the differential pressure data average value Adp stored in the storage unit 12 in advance. Is calculated as a correction value k (= Adps / Adp) (step S15).

 Furthermore, the dispersion ratio correction unit 9 calculates the corrected dispersion ratio Dcomp by multiplying the dispersion ratio D obtained from the dispersion ratio correction unit 9 by the correction value k as shown in the above equation (8), and the correction The dispersion ratio Dcomp is output to the clogging determination unit 10 (step S16). Then, similarly to the first embodiment, the clogging determination unit 10 determines the clogged state of the high-pressure side impulse line 3 and the low-pressure side impulse line 4 by comparing the corrected dispersion ratio Dcomp and a predetermined threshold value, The determination result is output to the display unit 11 (step S17).

  As described above, according to the pressure guiding tube blockage detection device of the second embodiment, only the differential pressure data Dp (i) larger than the threshold value LT is sampled, so that the flow rate changes drastically as in the intermittent flow condition. However, the clogged state of the pressure guiding tube can be accurately determined without being affected by the period during which no fluid flows.

  In the first and second embodiments, the equation (4) is used as an equation for calculating the differential pressure fluctuation Fdp (i). However, the equation (3) may be used instead of the equation (4). Good (subscript only changes). By using this equation (3), even if a transient change occurs in the differential pressure, the transient change component can be removed and only the true oscillation component can be captured.

  Furthermore, any of the following formulas (11) to (13) may be used as a formula for calculating the differential pressure fluctuation Fdp (i). These equations (11) to (13) are obtained by further dividing the above equation (3) by the current value Dp (i), the previous value Dp (i-1), or the previous value Dp (i-2) of the differential pressure data. It is a thing. By using these equations, it is possible to obtain an accurate differential pressure fluctuation Fdp (i) that is not influenced by a transient change component of the differential pressure or a change in flow rate.

1 is a schematic configuration diagram of a pressure guiding tube blockage detection device according to a first embodiment of the present invention. It is an operation | movement flowchart figure of the pressure guiding tube blockage detection apparatus in 1st Embodiment of this invention. It is a schematic diagram which shows the time change of the differential pressure data Dp (i) under intermittent flow conditions. It is an operation | movement flowchart figure of the pressure guiding tube blockage detection apparatus in 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piping, 2 ... Orifice, 3 ... High pressure side pressure guiding tube, 4 ... Low pressure side pressure guiding tube, 5, 5a ... Differential pressure transmitter (differential pressure detection means), 6 ... Differential pressure fluctuation calculation part, 7 ... Swing Dispersion calculation unit, 8 ... dispersion ratio calculation unit, 9 ... dispersion ratio correction unit, 10 ... clogging determination unit, 11 ... display unit, 12 ... storage unit

Claims (5)

Detects the differential pressure of the fluid based on the high pressure side pressure transmitted through the high pressure side pressure guiding tube and the low pressure side pressure transmitted through the low pressure side pressure guiding tube, and outputs time series data of the differential pressure. Differential pressure detection means;
Differential pressure fluctuation calculating means for calculating differential pressure fluctuation based on the time-series data of the differential pressure;
Oscillating dispersion calculating means for calculating dispersion of the differential pressure oscillating;
A dispersion ratio calculating means for calculating a dispersion ratio between the dispersion of the differential pressure fluctuation calculated by the fluctuation dispersion calculating means and the dispersion of the differential pressure fluctuation calculated in advance when the high pressure side pressure guiding tube and the low pressure side pressure guiding tube are normal; ,
Based on the time-series data of the differential pressure output from the differential pressure detection means and the time-series data of the differential pressure obtained in advance at the normal time, the change in the dispersion ratio due to the change in the flow rate of the fluid is suppressed. A dispersion ratio correction means for calculating a correction value and correcting the dispersion ratio by the correction value;
Clogging determining means for determining clogging of the high pressure side pressure guiding pipe and the low pressure side pressure guiding pipe based on the dispersion ratio corrected by the dispersion ratio correcting means;
A pressure guiding tube clogging detection apparatus comprising:   The dispersion ratio correcting means is a ratio Adps / Adp between an average value Adps of time series data of differential pressure obtained in advance during the normal time and an average value Adp of time series data of differential pressure output from the differential pressure detecting means. 2. The pressure guiding tube blockage detecting device according to claim 1, wherein the dispersion ratio is corrected by calculating as a correction value and multiplying the dispersion ratio by the correction value. The differential pressure detection means compares the detected differential pressure with a predetermined threshold value, and outputs time series data of the differential pressure greater than the threshold value,
The time-series data of the differential pressure obtained in advance at the normal time is a value larger than the predetermined threshold value, and the variance of the differential pressure fluctuation obtained in advance at the normal time is the predetermined pressure obtained in advance at the normal time. 3. The pressure guiding tube blockage detecting device according to claim 1, wherein the pressure guiding tube blockage detecting device is calculated based on time-series data of a differential pressure larger than a threshold value. The differential pressure fluctuation calculating means includes the following equation (11), which includes a current value Dp (i), a previous value Dp (i-1), and a previous value Dp (i-2) in the time series data of the differential pressure: The pressure guiding tube blockage detecting device according to any one of claims 1 to 3, wherein the differential pressure fluctuation Fdp (i) is calculated by using either of the formula (12) or the formula (13).

Based on the high pressure side pressure transmitted through the high pressure side pressure guiding tube and the low pressure side pressure transmitted through the low pressure side pressure guiding tube, the differential pressure of the fluid is detected, and time series data of the differential pressure is obtained. The first step;
A second step of calculating a differential pressure fluctuation based on the time series data of the differential pressure;
A third step of calculating a variance of the differential pressure fluctuation;
A fourth step of calculating a dispersion ratio between the dispersion of the differential pressure fluctuation calculated in the third step and the dispersion of the differential pressure fluctuation calculated in advance when the high pressure side pressure guiding tube and the low pressure side pressure guiding tube are normal;
Based on the time series data of the differential pressure acquired in the first step and the time series data of the differential pressure obtained in advance at the normal time, the change in the dispersion ratio due to the change in the flow rate of the fluid is suppressed. A fifth step of calculating a correction value;
A sixth step of correcting the dispersion ratio based on the correction value;
A seventh step of determining clogging of the high-pressure side impulse line and the low-pressure side impulse line based on the dispersion ratio corrected in the sixth step;
A pressure guiding tube clogging detection method comprising:

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