JP2020186930A - Pressurized piping system - Google Patents

Abstract

To provide a technique for detecting a flow rate without deteriorating accuracy due to installation conditions or piping conditions, while retaining the characteristics of a passive flow rate estimation system that can be easily installed in a pipe with a simple configuration.SOLUTION: A pressurized piping system of the present invention is provided with vibration sensors installed at a first location where a pressure fluctuation is large and at a second location where the pressure fluctuation is almost non-existent, respectively, and measures the fluid flow rate according to results of vibration measured by each sensor at two different times.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for detecting a fluid flow rate from the outside of a pipe.

The demand for energy sensing has been increasing in recent years as part of the sophistication (smart) of device control in factories. In particular, pipes for various types of fluids such as gas and steam are installed in factories, and from the viewpoint of efficient use of energy and reduction of pipe maintenance costs, it is necessary to have a technology to measure the fluids of these pipes with high accuracy. Has been done.

Generally, when measuring the fluid flow rate in a pipe, a pipe component with a flow meter is inserted into a part of the pipe as a path. In this method, the fluid and the sensor come into direct contact with each other, so that reliable calibration is possible. However, regardless of the new piping, it is necessary to cut the existing piping network and insert new parts, and fluid cannot be sent during the construction. This method is not always the optimum method depending on the factory equipment.

Therefore, a technique for detecting the flow rate from the outside of the pipe without processing the pipe has been developed. One is called the active type. This technology consists of two ultrasonic transducers, an ultrasonic transmission / reception circuit, a signal processing circuit, a display output circuit, and the like. The two ultrasonic transducers are arranged at a certain distance (several centimeters) determined by the gas type, the outer diameter of the pipe, the wall thickness of the pipe, etc., and are installed so as to be in contact with the outer peripheral portion of the pipe. Ultrasonic waves with frequencies such as 500 kHz and 1 MHz are transmitted and received between two ultrasonic transducers, the difference in ultrasonic wave propagation time is detected by signal processing, and the time difference is converted into a flow velocity or a flow rate.

Patent Document 1 below describes a so-called passive flow rate measuring method for directly measuring vibration generated by an interaction between a pipe and a fluid. In this method, the flow rate is measured by utilizing the fact that the magnitude of the energy of the vibration of the pipe generated by the movement of the fluid correlates with the flow rate.

JP-A-2018-115888

Since the conventional active flow rate measurement is easily affected by the difference in acoustic impedance between the pipe and the fluid, the type of fluid to be measured is limited. Ultrasound is greatly attenuated as it travels between the pipe and the fluid, especially in combinations where the acoustic impedances of the pipe and fluid differ significantly, such as fluids such as air and pipe materials such as steel. Therefore, in order to measure the flow rate accurately, a high-power transducer and a jig for bringing the sensor and piping into close contact with each other are required. As a result, the equipment becomes very expensive or the gas needs to be excluded from the fluid measurement target.

In conventional passive flow rate measurement, the information obtained from the correlation between vibration and flow rate is the relative amount of flow rate. In this method, the correlation between the flow rate obtained by the minimum flow meter installed in the piping network (for example, the outlet of the compressor) and the individual vibrations obtained by a large number of sensors placed in the branch pipe is used. Measure in advance and estimate the flow rate according to the correlation measured in advance with the measured value of each pipe in operation. However, in this method, there is no standard for where to install the sensor in the pipe, and there is only a vague view that "the signal from the vibration sensor installed in the pipe has a correlation with the flow rate".

The present invention has been made in view of the above problems, and the accuracy is reduced due to the influence of installation conditions and piping conditions while maintaining the characteristics of passive flow rate estimation that can be easily installed in piping with a simple configuration. It is an object of the present invention to provide a technique for detecting a flow rate without a flow rate.

In the pressurized piping system according to the present invention, vibration sensors are installed at the first location where the pressure fluctuation is large and at the second location where the pressure fluctuation is almost nonexistent, and the vibration is measured at two different times by each sensor according to the result. , Measure the fluid flow rate.

According to the pressurized piping system according to the present invention, the flow rate of the fluid flowing inside the piping can be accurately measured by using a sensor that can be easily installed on the outside of the piping, regardless of the type of fluid.

It is a block diagram of the pressure piping system 100 which concerns on Embodiment 1. FIG. The average power value of the output signal obtained by limiting the output signal of the vibration sensor installed immediately next to the downstream pipe of the pressure reducing valve 105 by a band (20 KHz to 30 kHz) is shown. Using a statistical method (moving average), the variation in FIG. 2 was reduced to about 2%. Similar to FIG. 2, the average power value of the output signal of the sensor 106 installed on the valve 107 is smoothed to a variation of about 2%. The output pressure of the air compressor 101 is shown. The vibration in the pressure reducing valve 105 is shown. The vibration in the pressure reducing valve 105 is shown. It is a schematic diagram which shows the relationship between the flow rate in a valve and a filter, and a sensor output signal. It is a schematic diagram which shows the relationship between the flow rate in a pressure reducing valve and a sensor output signal. It is a figure which shows the time-dependent change of the output signal P of a sensor 104. It is a figure which shows the time-dependent change of the output signal Q of a sensor 106. It is a graph which shows the relationship between the coefficient α and the flow rate F. It is a graph which shows the relationship between the coefficient α and the flow rate F. It is a graph which illustrates the time-dependent change of the output signal Q of the sensor 106 when the flow rate suddenly changes. It is a graph which illustrates the time-dependent change of the output signal P of the sensor 104 when the flow rate suddenly changes. It is a flowchart explaining the operation performed by the flow rate estimation apparatus 110 in the calibration process of a pressure piping system 100. It is a flowchart explaining the procedure which the flow rate estimation apparatus 110 estimates the flow rate after the pressurization piping system 100 starts operation. It is a block diagram of the pressure piping system 100 which concerns on Embodiment 2. It is a block diagram of the pressure piping system 100 which concerns on Embodiment 3. This is an example of a look-up table in which the flow rate F is defined by the output signal P at time t1 and the output signal P at time t2. This is another example of a lookup table. This is another example of a lookup table.

<Embodiment 1: System configuration>
FIG. 1 is a configuration diagram of a pressurized piping system 100 according to a first embodiment of the present invention. The pressurized piping system 100 branches from one air compressor 101 into a plurality of piping and supplies air to each load. In the following, when the same component exists more than once, each part is distinguished by adding subscripts 1 to N and the like. Subscripts are omitted when the same components are collectively referred to.

The output of the air compressor 101 is connected to the receiver tank 102 and branched into a plurality of pipes via the valve 103. Each branch pipe is connected to the load device 108 via the pressure reducing valve 105 and the valve 107. Sensors 104 and 106 are installed in each pipe. Each sensor is a sensor that detects the vibration level. The sensor 104 is installed at a position in contact with the inlet of the pressure reducing valve 105 (the side closer to the air compressor 101, that is, the air inlet, the same applies hereinafter) and the outer periphery of the pipe. The sensor 106 is installed at a position in contact with the inlet of the valve 107 and in contact with the outer periphery of the pipe. The data converter 109 converts the output signal of each sensor into digital data, and the flow rate estimation device 110 (processing device) converts the digital data into flow rate. The flow rate estimation device 110 acquires the output signal of the sensor 104 and the output signal of the sensor 106 at at least two different times, and estimates the fluid flow rate using the obtained at least four output signals. The detailed procedure will be described later.

<Embodiment 1: Conventional flow rate estimation>
Generally, the vibration caused by the movement of gas is based on a part of energy loss (pressure loss) caused by friction between the gas and the inner wall surface of the pipe. A pipe with an inner surface with a large friction has more pressure loss than a pipe with a smooth inner surface even if the same flow rate of gas is passed. Elbow pipes and branch pipes that change the direction of gas, filters that remove gas dust, and valves that adjust the flow rate have higher pressure loss than simple pipes. It can be said that the pressure loss is also high in the pressure adjusting part such as the pressure reducing valve because the pressure loss generation itself is the function.

All attempts to passively estimate the flow rate by installing a vibration sensor in the pipe are by measuring this pressure loss. Naturally, the part suitable for attaching the vibration sensor is the part with a large pressure loss. Even if it is just an inner wall of a pipe, some vibration is generated due to friction, but it is difficult to obtain a large signal because it is desirable that the pipe has little pressure loss. On the other hand, parts that change pressure, such as pressure reducing valves, are considered to be most suitable for vibration detection because their purpose is to generate pressure loss and their signal level is high. Therefore, it can be said that it is desirable to use the vibration in the pressure reducing valve for the flow rate sensing by the vibration measurement. Alternatively, although the pressure loss is smaller than that of the pressure reducing valve, it can be said that the filter and the valve in the middle of piping are also suitable for flow rate sensing by vibration measurement.

The average power value of the output signal of the vibration sensor is proportional to the square of the flow rate and also to the pressure loss itself. This will be explained by the following equation. The pressure loss (Δp) due to the friction and the flow rate of the pipe is expressed by the relational expression of Darcy-Weisbach shown by the following equation 1. ρ is the density of the gas, λ is the loss factor due to friction at the site, and F is the flow rate. Equation 2 shows the relationship between the pressure loss and the average power value. P is the power of the output signal of the sensor. Volume and pressure are represented by lower letters v and p, and are distinguished from voltage V, output signal power P, and output signal power Q. k is a proportional constant that reflects the sensor and its installation status.

Δp (ρ, F) = ρ × λ (F) × F ² (1)
Ave | P | = k × Δp (ρ, F) = K (ρ) × F (2)

The loss factor of the inner surface of the pipe, the filter, the valve, etc. changes according to the condition (rust on the wall surface, clogging of the filter, twist angle of the valve, etc.), but it is considered to be the same in a short period of time. In the case of pipe inner surfaces and filters, the loss factor is often the reciprocal of the Reynolds number. Since the Reynolds number is proportional to the flow rate, the pressure loss Δp is proportional to the first power of the flow rate F when viewed as the whole equation 1. Since the loss coefficient of the elbow pipe or valve does not depend on the Reynolds number, the pressure loss Δp is proportional to the square of the flow rate F. Since the average power value of the sensor is proportional to the pressure loss as shown in Equation 2, it can be written in the form of the product of the proportional coefficient K depending on the gas density ρ and the flow rate F (or its square F ² ).

<Embodiment 1: Principle of flow rate estimation in the present invention>
The inventor of the present application has obtained the following findings on the premise of the principles described above. In the experimental evaluation using simulated piping in the process leading to the present invention, it is clear that the vibration of the flow rate piping is based on a part of the energy (pressure loss) lost in the part where the pressure of the fluid flowing in the piping changes. became. That is, the vibration generated in the actual piping reflects the flow noise at the pressure loss portion such as the valve and the pressure reducing valve.

It is imagined that this pressure loss tends to differ in the time direction depending on the location even at a constant flow rate. For example, when a mechanism for keeping the pressure constant, such as a pressure reducing valve 105 (regulator for pressure), exists in the pressure piping system 200, the fluid pressure changes due to the operation of the air compressor 101 before passing through the pressure reducing valve 105. After passing through the pressure reducing valve 105, the fluid pressure becomes almost constant. That is, the temporal change in the magnitude of pressure loss differs depending on the location on the pipe. Therefore, if the magnitude of vibration (or the signal power of the vibration sensor) and the flow rate are simply estimated in association with each other, the accuracy may be significantly reduced. Further, even in a place where the pressure is constant, such as a place after the pressure reducing valve 105, if the filter is used for a long time, the degree of pressure loss when passing through the filter changes with time (deterioration with time). ) May be. A similar problem arises in this case as well.

The pressurized piping system 100 repeats the operation and non-operation of the air compressor 101. The air compressor 101 monitors the pressure at the inlet of the receiver tank 102, continues the compression operation until a predetermined pressure is reached, and stops the operation when this pressure is reached. The pressure drops due to the air consumption in the load device 108, and when the pressure drops below a predetermined pressure, the operation is restarted. That is, the pressure in the pipe close to the air compressor 101 changes according to the operation of the air compressor 101 and further according to the load consumption. On the other hand, since the load device 108 requires air having a predetermined (constant) pressure, the pressure reducing valve 105 supplies air having a constant pressure. From this, in the piping from the air compressor 101 to the pressure reducing valve 105, the pressure changes according to the operation of the air compressor 101, and in the piping from the pressure reducing valve 105 to the load device 108, the air compressor 101 The pressure is constant regardless of the operation (or the fluctuation range that remains to the extent that the operation of the load device 108 is not hindered).

In view of the above functions of the pressure reducing valve 105, it can be said that the pressure loss Δp in the pressure reducing valve 105 is the difference between the input pressure and the set pressure without depending on the flow rate F. Since the set pressure is constant, the pressure loss Δp can be said to be a function of only the input pressure p _in. That is loss coefficient λ in the pressure reducing valve 105, which is a function of the input pressure _{p in.} Further, since the pressure loss Δp is not affected by the flow rate F, the loss coefficient λ can be said to be a function of canceling the subsequent term of the flow rate F. Thus the loss factor in the decompression valve 105 lambda can be said to be a function of the input pressure p _in the flow rate F. That is, the following equation 3 holds.

_{Δp (p in) = λ (} p in, F) × F 2 (3)

Furthermore, the inventor of the present application has found that the average power of the output signal of the sensor 104 is proportional to the square of the flow rate F, even though the pressure loss is constant. That is, the following equation 4 holds. In other words, it can be written in the form of square F ² of the product of the proportionality factor K and the flow rate is dependent on the input pressure p _in.

Ave | P | = k × Δp (p in) × F 2 = K (p in) × F 2 (4)

FIG. 2 shows the power value of the output signal obtained by limiting the output signal of the vibration sensor installed immediately next to the downstream pipe of the pressure reducing valve 105 by a band (20 KHz to 30 kHz). Each plot obtained an average power of about 6 ms, and was measured by changing the flow rate in five ways. There is a variation of about 1σ = 10% at each flow rate, but this is due to the vibration of the sound source due to turbulence and has a wide frequency component.

FIG. 3A shows that the variation in FIG. 2 is reduced to about 2% by using a statistical method (moving average). FIG. 3A shows the output signal of the sensor 104 installed in the same pressure reducing valve 105 as in FIG. The output signal of the sensor 104 tends to decrease with time. This is linked to the output of the air compressor 101, which will be described later.

FIG. 3B is the same as in FIG. 2, in which the average power value of the output signal of the sensor 106 installed on the valve 107 is smoothed to a variation of about 2%. It can be seen that the average power of the output signal of the sensor 106 differs depending on the flow rate. However, since it has passed through the pressure reducing valve 105, it can be seen that there is almost no change with time.

FIG. 4 shows the output pressure of the air compressor 101. Since the air compressor 101 repeats an operating state and a stopped state, the output pressure increases or decreases. It can be seen that the change with time in FIG. 3A has the same tendency as the change with time of the output pressure of the air compressor 101.

FIG. 5A shows the vibration in the pressure reducing valve 105. The vertical axis is the output pressure of the air compressor 101. The horizontal axis is the average power of the output signal of the sensor 104. The set pressure of the pressure reducing valve 105 is 0.3 MPa. It can be seen that the vibration level tends to approach 0 as the output pressure of the air compressor 101 approaches the set pressure. This tendency is the same regardless of the flow rate.

FIG. 5B shows the vibration in the pressure reducing valve 105. The set pressure of the pressure reducing valve 105 is 0.4 MPa. Others are the same as in FIG. 5A. Also in FIG. 5B, it can be seen that the vibration level tends to approach 0 as the output pressure of the air compressor 101 approaches the set pressure. This tendency is the same regardless of the flow rate.

According to the relationship shown in FIGS. 5A and 5B, the output signal (P) of the sensor 104 installed at the inlet of the pressure reducing valve 105 and the output pressure during the period when the output pressure of the air compressor 101 changes with time. It can be said that the relationship between them can be specified for each flow rate. This is because in FIGS. 5A and 5B, a clearly separated relationship can be seen for each flow rate. Therefore, it is considered that a coefficient representing this relationship can be calculated in advance (for example, in the calibration step before the start of operation), and the flow rate can be calculated using the coefficient and the sensor output signal after the start of operation.

FIG. 6A is a schematic diagram showing the time course of the relationship between the flow rate and the sensor output signal in the valve or filter. For example, the output signal of the sensor 106 corresponds to FIG. 6A. The vertical axis represents the average power P of the output signal of the sensor, and the horizontal axis represents the flow rate F. Regarding the horizontal axis, if the power P has a square relationship with F in Equation 2, it has a linear relationship even if it is replaced with F ² . The slope of a straight line indicating the correspondence of the output signal with respect to the flow rate represents the proportional coefficient K as shown in Equation 2. If the gas density is constant, the slope does not change. However, with the passage of time, the loss coefficient λ may change and tilt depending on the state of the valve and the clogging of the filter. In this case, the relationship between the sensor output and the flow rate in the valve or filter also changes with time. However, since this change with time gradually occurs over a relatively long period of time, the slope can be regarded as constant in a short period of time.

FIG. 6B is a schematic view showing the time course of the relationship between the flow rate and the sensor output signal in the pressure reducing valve. For example, the output signal of the sensor 104 corresponds to FIG. 6B. In Equation 4, the power P is the square of F, so if the horizontal axis corresponds to the square F ^{2 of the} flow rate and the vertical axis corresponds to the average power P of the output signal, the relationship becomes a straight line, and the slope of the straight line is It represents the proportional coefficient K as shown in Equation 4. Pressure drop Δp in the vicinity the pressure reducing valve 105 relies on input pressure p _in a set pressure as described in Equation 3. At the same time, as described in Equation 4, the output signal P of the sensor 104 is proportional to the flow rate F and the pressure drop Δp. It can be seen that when the input pressure, that is, the pressure loss, changes, the loss coefficient, which is a proportional coefficient thereof, also changes, and the slope of the straight line also changes. Since this change in inclination reflects the change in input pressure, it is a change over time in a much shorter period than in FIG. 6A. Therefore, in the present invention, attention is paid to the linear inclination, that is, the change with time of the average power in the relationship between the flow rate in the pressure reducing valve and the sensor output signal.

FIG. 7A is a diagram showing a change over time in the average power P of the output signal of the sensor 104. Here, the change with time during the period in which the operation of the air compressor 101 is stopped and the load device 108 is consuming a constant flow rate of air is shown. The air compressor 101 shifts from the stopped state to the operating state before the fluid pressure becomes less than the set value, and shifts to the stopped state when the fluid pressure rises sufficiently. The air compressor 101 repeats this. Therefore, even if the flow rate A is constant, the input pressure to the pressure reducing valve 105 changes with time, so that the pressure loss Δp also changes with time. Since the sensor 104 detects the vibration caused by the pressure loss Δp according to the equation 4, the output signal P also changes with time. The straight line shown by the flow rate F1 in FIG. 7A shows this relationship when the air compressor 101 is stopped.

On a straight line of the flow rate F1 of Figure 7A, to obtain an output signal _{P F11} and _{P F12} in ₁ and _{t 2,} respectively two times for different _t respectively. As a result, the coefficient α represented by the following equation 5 can be obtained. This coefficient α represents the slope of the straight line of the flow rate F1 in FIG. 7A. Further, the flow rate F1 at this time is separately measured by a measuring instrument. Similarly, for the flow rate F2, the coefficient α can be obtained according to Equation 5. This will be described with reference to FIG. 8B.

α = ΔP / ΔT ₁₂ (5)

Since the coefficient α in Equation 5 is the slope of the straight line on FIG. 7A, it will be constant if the flow rate does not change. In other words, by obtaining the relationship between the coefficient α and the flow rate in advance, the coefficient α after the start of operation of the pressurized piping system 100 can be actually measured and the flow rate can be calculated according to the relationship. The above procedure is carried out before the start of operation of the pressurized piping system 100 (for example, a calibration step), and the relationship between the coefficient α and the flow rate is maintained in the flow rate estimation device 110. The flow rate estimation device 110 estimates the flow rate using this relationship.

FIG. 7B is a diagram showing a change over time in the average power Q of the output signal of the sensor 106. Since the sensor 106 is arranged at a position where the fluid pressure is constant, the output signal Q of the sensor 106 does not change with time and is constant. However, when the flow rate changes, the output signal Q also has a value corresponding to the flow rate. How to use the relationship shown in FIG. 7B will be described with reference to FIGS. 9A and 9B described later.

FIG. 8A is a graph showing the relationship between the coefficient α and the flow rate F. The coefficient α and the flow rate F have a proportional relationship. Therefore, for example, the relationship between the coefficient α and the flow rate F can be obtained by obtaining the coefficient α _F1 at the flow rate F1 in FIG. 7A. The flow rate estimation device 110 can acquire the relationship shown in FIG. 8A in advance by actually measuring the flow rate F and the coefficient α, for example, in the calibration step of the pressurized piping system 100.

FIG. 8B is a graph showing the relationship between the coefficient α and the flow rate F. When the relationship between the flow rate F and the coefficient α is actually measured twice or more in the calibration step or the like, the dotted line shown in FIG. 8B is calculated by an appropriate method such as the least squares method for each measured result. As a result, the relationship between the coefficient α and the flow rate F can be obtained more accurately. If the straight line obtained at this time does not pass through the origin, there is a possibility that background noise or the like is being picked up.

FIG. 9A is a graph illustrating the time-dependent change of the output signal Q of the sensor 106 when the flow rate suddenly changes. Here, it is assumed that the flow rate suddenly changes from F1 to F2. As shown in FIG. 7B, since the sensor 106 is arranged at a position where the pressure is constant, the output signal Q is originally constant. Therefore, when the fluctuation as shown in FIG. 9A occurs, it is considered that the relationship between the flow rate F and the output signal P of the sensor 104 also changed as shown in FIG. 6B.

FIG. 9B is a graph illustrating the time-dependent change of the output signal P of the sensor 104 when the flow rate suddenly changes. If the flow rate is suddenly changed, it means obtaining the coefficient α by using the two output signals P _F1 and P _F2 correspond to different flow rates F1 and F2 to each other would otherwise, correspondence between the flow rate F and the coefficient α Is calculated incorrectly. Therefore, when the flow rate changes suddenly, the method described with reference to FIGS. 7A to 8B should not be used until the flow rate stabilizes.

For the reason described above, when the output signal Q of the sensor 106 is not constant (that is, Q _F11 ! = Q _F12 or Q _F21 ! = Q _F22 in FIG. 7B), the flow rate estimation device 110 and the output signal P of the sensor 104 The relationship of flow rate F is regarded as invalid. However, in consideration of the variation in the measurement result, a certain range may be expected in conjunction with the number of moving averages, and when the following equation 6 is satisfied, the relationship between the signal P and the flow rate F may be regarded as invalid.

| ΔQ ₁₂ |> ε (6)

FIG. 10A is a flowchart illustrating the operation performed by the flow rate estimation device 110 in the calibration process of the pressurized piping system 100. The flow rate estimation device 110 keeps the latest calibration result as much as possible by, for example, periodically performing this flowchart. Each step of FIG. 10 will be described below.

(FIG. 10A: steps S1001 to S1004)
When the air compressor 101 starts operating (S1001), the flow rate estimation device 110 acquires the flow rate value F inside the pipe from the flow meter (S1002). The flow rate estimation device 110 calculates the voltage value of the output signal of the sensor 104 (S1003). The flow rate estimation device 110 similarly calculates the voltage value of the output signal of the sensor 106 (S1004).

(FIG. 10A: Steps S1003 to S1004: Supplement)
The flow rate estimation device 110 can calculate the voltage value of each sensor by the following procedure, for example. The flow rate estimation device 110 first acquires the voltage signal of the output signal of the sensor, and converts the voltage signal into each frequency component by Fourier transform. The flow rate estimation device 110 integrates (averages) the power levels for each frequency band and obtains the voltage value by obtaining the square root of the power.

(FIG. 10A: steps S1005 to S1007)
The flow rate estimation device 110 waits for a time corresponding to ΔT ₁₂ described with reference to FIGS. 7A to 7B (S1005). The flow rate estimation device 110 obtains the voltage value of each sensor in the same manner as in S1003 to S1004 (S1006 to S1007).

(FIG. 10A: Steps S1008 to S1009)
The flow rate estimation device 110 compares the change with time of the voltage level of the output signal Q of the sensor 106 | ΔQ ₁₂ | (Q _F1- Q _F2 in FIG. 9A) with the threshold value ε (Equation 6) (S1008). If | ΔQ ₁₂ | is larger, it is considered that the flow rate has changed significantly, and the air compressor 101 waits until it stops (S1009). If | ΔQ ₁₂ | ≦ ε, the process proceeds to S1010.

(FIG. 10A: steps S101 to S1012)
The flow rate estimation device 110 calculates the coefficient α according to Equation 5 (S1010). The flow rate estimation device 110 calculates the relationship between the flow rate F and the coefficient α and stores it in the storage device (S1011). The air compressor 101 is stopped to end the calibration step (S1012).

FIG. 10B is a flowchart illustrating a procedure in which the flow rate estimation device 110 estimates the flow rate after the pressurized piping system 100 starts operation. The same step numbers were assigned to the same steps as in FIG. 10A. The flow rate estimation device 110 calculates the coefficient α according to the measured value of each sensor by the same procedure as in FIG. 10A. The flow rate estimation device 110 calculates the flow rate F from the actually measured coefficient α according to the relationship between the flow rate F and the coefficient α obtained in advance in FIG. 10A (S1101). If | ΔQ ₁₂ | is larger than ε, the process returns to S1003 and the same process is repeated (S1102).

<Embodiment 1: Summary>
In the pressurized piping system 100 according to the first embodiment, the flow rate estimation device 110 calculates the flow rate using the output signal P of the sensor 104 (that is, the vibration at the inlet of the pressure reducing valve 105 where the fluid pressure fluctuates). At the same time, if the output signal Q of the sensor 106 (that is, the vibration at the inlet of the valve 107 (or filter) where the fluid pressure hardly fluctuates) suddenly changes, the flow rate estimation is suspended until the fluid pressure stabilizes. By adopting this method, the flow rate can be calculated by utilizing the change in fluid pressure, and the flow rate can be estimated accurately by suppressing the influence of the change in the state of the pressure-damaged component.

<Embodiment 2>
FIG. 11 is a block diagram of the pressurized piping system 100 according to the second embodiment of the present invention. The pressurized piping system 100 shown in FIG. 11 includes a pump 1101 instead of the air compressor 101, and a water storage tank 1102 instead of the receiver tank 102. Others have the same configuration as that of the first embodiment. The water output by the pump 1101 is stored in the water storage tank 1102, and the water flow is branched to a plurality of pipes via the valve 103.

The liquid raised in the water storage tank 1102 has a pressure depending on the drop between the pressure drop component and the liquid. Since the load device 108 requires a liquid having a predetermined (constant) pressure, the pressure is made constant via the pressure reducing valve 105. Therefore, the fluid pressure is a value corresponding to the difference between the position of the water storage tank 1102 and the pipe position in the pipe from the water storage tank 1102 to the pressure reducing valve 105, and the pressure reducing valve 105 is set in the pipe from the pressure reducing valve 105 to the load device 108. It becomes pressure.

The pressure of the liquid output from the water storage tank 1102 is determined by the height of the liquid level and the drop between the pressure-loss parts. If the bottom surface dimension of the water storage tank 1102 is sufficiently longer than the height direction dimension, or if the height direction dimension of the water storage tank 1102 is sufficiently large compared to the head, the fluid pressure in the pressure drop component is "almost" constant. I can say. The same applies when the liquid is always supplied to the water storage tank 1102 by the continuous operation of the pump 1101 and the height of the liquid level does not change. In this case, it is not always necessary to use the present invention. On the other hand, when the water surface decreases with time and the pressure changes, the method according to the present invention is useful. However, it should be noted that when the fluid is a liquid, unlike a gas, the density can be assumed to be constant.

In the pressurized piping system 100 that supplies a liquid as in the second embodiment, the flow rate can be calculated by utilizing the change in the fluid pressure by the same method as in the first embodiment, and the state change of the pressure-damaged component can be calculated. The flow rate can be estimated accurately by suppressing the influence of.

<Embodiment 3>
FIG. 12 is a block diagram of the pressurized piping system 100 according to the third embodiment of the present invention. In the configuration described in the first and second embodiments, the flow rate estimation device 110 may acquire an output signal from each sensor at the timing when the air compressor 101 (or the pump 1101, the same applies hereinafter) is operating. .. In this case, the flow rate estimation device 110 acquires the operation status data describing the operation status of the air compressor 101 from the air compressor 101, and acquires the sensor output signal accordingly. Other configurations are the same as those of the first and second embodiments.

The timing at which the flow rate estimation device 110 acquires the sensor output signal can also be manually specified by the operator, for example. For example, it is conceivable to set an appropriate timing so that the sensor output signal is not acquired over the period in which the air compressor 101 is operating and the period in which it is stopped. As shown in FIG. 12, by determining the timing for acquiring the sensor output signal according to the operating status data, it is possible to reduce the time and effort of manual operation and to obtain the sensor output signal at an appropriate timing. Therefore, the accuracy of flow rate estimation can be improved.

<Embodiment 4>
In the first to third embodiments, the procedure for estimating the flow rate based on the output signal P of the sensor 104 has been described. The relationship between the coefficient α and the flow rate F can be held in the graph format as shown in FIGS. 8A to 8B, or can be held in the lookup table format. In the fourth embodiment of the present invention, an example of holding the look-up table format will be described. The configuration of the pressurized piping system 100 is the same as that of the first to third embodiments.

FIG. 13A is an example of a look-up table in which the flow rate F is defined by the output signal P at time t1 and the output signal P at time t2. The times t1 and t2 correspond to the time on the horizontal axis in FIG. 7A. The flow rate estimation device 110 acquires the intersection of the values of the output signals P at each of the times t1 and t2 as the flow rate F.

FIG. 13B is another example of a look-up table. Since the output signal P has a certain degree of variation due to turbulence, it is more practical to define each axis of the lookup table as a signal value range having a certain range. Therefore, in the look-up table shown in FIG. 13B, the output signal force range obtained at time t1 is defined as the vertical axis, and the output signal range obtained at time t2 is defined as the horizontal axis. The size of the variation representing one range depends on the number of moving averages, but it is considered that it is good to allow for a few percent equivalent to 1σ, for example. In FIG. 13B, one range is set to 10%, but a narrower range may be used or a wider range may be used.

FIG. 13C is another example of a look-up table. Even if the time interval for acquiring the sensor output signal is constant, it is assumed that the actually acquired sensor output signal may deviate from the one at the time of calibration depending on the time. Therefore, in FIG. 13C, the output signal range at time t2 is defined as a relative value from the output signal range at time t1. In this case, since the output signal value at time t2 is relativized with respect to the output signal value at time t1, as long as ΔT ₁₂ is constant, the estimation result is not affected. Relative values may be defined by ratio or by difference. FIG. 13C shows an example defined by the ratio.

<About a modified example of the present invention>
The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

The flow rate estimation device 110 can be configured by hardware such as a circuit device that implements the function, or can be configured by the arithmetic unit executing software that implements the function.

101: Air compressor 102: Receiver tank 103: Valve 104: Sensor 105: Pressure reducing valve 106: Sensor 107: Valve 108: Load device 109: Data converter 110: Flow rate estimation device 1101: Pump 1102: Water storage tank

Claims (11)

Pressurizer,
Piping for flowing the fluid sent from the pressurizer,
Two or more sensors installed in the pipe to sense the vibration of the pipe,
A processing device that processes a signal from the sensor,
With
The sensors are installed at the first and second locations.
The first location is the outlet or inlet of the first pressure drop component.
The second location is the outlet or inlet of the second pressure drop component.
The pressure fluctuation of the fluid at the inlet of the first pressure drop component is larger than the pressure fluctuation of the fluid at the inlet of the second pressure drop component.
The processing device is characterized in that it measures the output signal of the sensor at two or more different times, estimates the flow rate of the fluid inside the pipe based on the output signal, and outputs the flow rate value. Pressurized piping system. The pressurized piping system according to claim 1, wherein the pressurizer is an air compressor, and the fluid flowing through the piping is compressed air. The pressurizing piping system according to claim 1, wherein the pressurizing device is a pump, and the fluid flowing through the piping is a liquid. The processing device uses the measured value based on the signal of the sensor installed at the first location at the time, and refers to the look-up table stored in the database to refer to the fluid inside the pipe. The pressurized piping system according to claim 1, wherein the flow rate is estimated. The processing device estimates the flow rate of the fluid inside the pipe based on the slope of the measured value based on the signal of the sensor installed at the first location at the two or more different times. The pressurized piping system according to claim 1. The first aspect of the present invention, wherein the processing apparatus estimates the flow rate of the fluid inside the pipe when the measured values of the sensors installed at the second location do not change at at least two times. Pressurized piping system. The pressurized piping system according to claim 1, wherein the sensor outputs electric power, current, or voltage as a measured value. The pressurized piping system according to claim 1, wherein the processing device further includes a display device for displaying a setting screen used for setting the two or more different times. The processing device further comprises an interface that presents the operating state of the pressurizer.
The first time, which is one of the two or more different times, is a time after the time when the pressurizer is turned from OFF to ON.
The pressurized piping system according to claim 1, wherein the second time, which is another one of the two or more different times, is a time after the first time. Pressurizer,
Piping for flowing the fluid sent from the pressurizer,
Two or more sensors installed in the pipe to sense the vibration of the pipe,
A processing device that processes a signal from the sensor,
With
The pressurizer is an air compressor
The fluid is compressed air
The sensors are installed at the first and second locations.
The first location is the outlet or inlet of the first pressure drop component.
The second location is the outlet or inlet of the second pressure drop component.
The pressure fluctuation of the fluid at the inlet of the first pressure drop component is larger than the pressure fluctuation of the fluid at the inlet of the second pressure drop component.
The processing device measures the output signal of the sensor at one or more different times, estimates the flow rate of the fluid inside the pipe based on the output signal, and outputs the flow rate value. Pressurized piping system. Pressurizer,
Piping for flowing the fluid sent from the pressurizer,
Two or more sensors installed in the pipe to sense the vibration of the pipe,
A processing device that processes a signal from the sensor,
With
The sensors are installed at the first and second locations.
The first location is the outlet or inlet of the first pressure drop component.
The second location is the outlet or inlet of the second pressure drop component.
The pressure fluctuation of the fluid at the inlet of the first pressure drop component is larger than the pressure fluctuation of the fluid at the inlet of the second pressure drop component.
The processing device measures the output signal of the sensor at two or more different times.
The processing device estimates the flow rate of the fluid inside the pipe based on the slope of the measured value based on the output signal of the sensor installed in the first pressure drop component at the two or more different times.
The processing device is characterized in that the flow rate of the fluid inside the pipe is estimated only when the measured values of the sensors installed in the second pressure drop component at two or more different times are constant. Pressurized piping system.

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