JP2004157055A - Air leak amount detector and flowmeter equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air leak amount detector for always accurately detecting the amount of air leak of an air supply device installed in a factory regardless of changes in the atmospheric temperature in the factory, and to provide a flowmeter provided therewith. <P>SOLUTION: An air leak amount detector 20 comprises a pressure sensor 12 that measures the air pressure within air supply piping, a temperature sensor 13 that measures the air temperature in air piping, and a pressure drop time measuring part 16 that measures the pressure drop time from when the pressure value of the pressure sensor drops to a first pressure value till it drops to a second pressure value which is lower than the first one. The pressure drop time measuring part comprises a pressure correcting part 16a that cancels the air pressure changing amount that follows only the air temperature changing amount since the first pressure value is detected on the basis of the output of the temperature sensor, before the second pressure value is detected after the first pressure value is detected. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air leak detection device that measures an air leak from a pipe of an air supply device used as a power source of a factory, and a flow meter including the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, in a vehicle assembly plant of an automobile, air is supplied to drive an actuator such as a tool such as an impact wrench or a window mounting device. In supplying such driving air, air is used in various places in the factory, so that an infinite number of air piping devices connected to the compressor are branched to supply air to desired working areas. ing.
[0003]
Since air pipes are branched and connected via a large number of joints (couplings) for supplying air in such factory equipment, air leakage (leakage) necessarily occurs at various places. By measuring the amount of air leak caused by this leak, a device that can confirm how much air of the compressor drive power is used as wasted power in air supply due to the leak is required. I have.
[0004]
Although it is conceivable to measure such an air leak amount only with a flow meter, it is not suitable for use because a flow rate alone cannot measure a minute flow rate or a backflow.
[0005]
On the other hand, as a conventional technique for detecting a gas leak in a pipe, a shut-off valve is closed in a state where an internal combustion engine is stopped, and in this state, a pressure reduction amount of a gas fuel in a fuel pipe after a certain time has elapsed is measured. 2. Description of the Related Art There is known a gas fuel supply device that detects leakage of fuel from a fuel pipe (for example, see Patent Document 1).
[0006]
[Patent Document 1] JP-A-2001-304000 (page 4-5, FIG. 1)
[Problems to be solved by the invention]
In general, air pipes in a factory are arranged endlessly in the factory. Further, in the summer, for example, the ambient temperature in the factory changes considerably due to the non-operation of the cooling in the factory when the factory is operating and when the factory is stopped. Then, the air temperature in the air pipe changes considerably according to this. Therefore, in a device that simply measures the air pressure in the air pipe with a pressure sensor and checks the amount of air leak according to the reduced amount of the pressure, an accurate amount of air leak is detected because the air is a compressible fluid. I can't. With respect to the detection of fuel gas leakage in the gas fuel supply device described above, the purpose is to determine the leakage of gas which should not be leaked, and the pressure reduction amount in the fuel pipe is measured using only the pressure sensor. To judge instantaneously the leakage of gas fuel. Therefore, this is different from the subject of the present invention, that is, the subject of accurately detecting the air leak amount on the premise of a certain degree of leak without being affected by a change in the ambient temperature.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide an air leak amount detecting device that always accurately detects an air leak amount of an air supply device installed in a factory or the like irrespective of a change in the ambient temperature in the factory, and a flow meter including the air leak amount detecting device. Is to provide.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, an air leak amount detection device according to the present invention has a power supply compressor including an air supply compressor and an air supply pipe connected to the compressor for supplying air to a desired position. A pressure sensor for measuring the air pressure in the air supply pipe, a temperature sensor for measuring the air temperature in the air pipe, and a pressure value measured by the pressure sensor. Pressure descent time measuring means for measuring a pressure descent time from a time when the pressure value has been lowered to a second pressure value lower than the first pressure value, wherein the pressure descent time measuring means comprises a temperature sensor From the first pressure value detection to the second pressure value detection on the basis of the output of the first pressure value, the pressure correction means for canceling the air pressure change only due to the air temperature change from the first pressure value detection. hand That.
[0009]
In measuring the pressure drop time from the first pressure value to the second pressure value using the pressure drop time measuring means, the air pressure change amount based on only the air temperature change amount after the first pressure value is detected is canceled. Therefore, even if there is a temperature change of the air within the pressure fall time measurement time, the measured pressure is not affected by this, and an accurate air leak amount is always converted to the pressure fall time and found.
[0010]
An air leak amount detecting device according to a second aspect of the present invention is a power air supply device including a compressor for supplying air and an air supply pipe connected to the compressor for supplying air to a desired position. A pressure sensor for measuring the air pressure in the air supply pipe, a temperature sensor for measuring the air temperature in the air supply pipe, and a pressure sensor for measuring the air pressure in the air supply pipe. Is measured from the time when the pressure value decreases to the second pressure value to the second pressure value lower than the first pressure value, and from the time when the pressure value increases to the second pressure value to the first pressure value. Pressure change time measurement means for measuring a pressure rise time until the pressure value rises to a pressure value, wherein the pressure change time measurement means detects the second pressure value after the first pressure value is detected by the pressure sensor when the pressure drops. For up to In addition to canceling the change in air pressure caused only by the change in air temperature from the time of detection of the first pressure value, the first pressure value is detected after the detection of the second pressure value by the pressure sensor when the pressure rises. Pressure correction means for canceling the change in air pressure caused only by the change in air temperature from the time when the pressure value is detected, and the relative time between the pressure rise time and the pressure fall time measured by the pressure change time measurement means. An air leak rate calculating means for calculating an air leak rate from the relationship is provided.
[0011]
Similarly to the air leak amount detecting device according to claim 1, the pressure correcting means can cancel the shift amount of the air pressure due to only the temperature change of the air during the pressure rise time or the pressure fall time, and thus accurate air leak can be achieved. Calculate the rate.
[0012]
Further, the pressure rise time from the second pressure value to the first pressure value when the pressure rises when the compressor is started and the pressure fall time from the first pressure value to the second pressure value when the pressure falls are relatively determined. By performing the comparison, an accurate air leak rate is always calculated irrespective of the type and arrangement of the air pipe to which the air leak amount detecting device is attached.
[0013]
An air leak amount detecting device according to a third aspect of the present invention is the air leak amount detecting device according to the second aspect, wherein the leak rate and the energy consumption per unit time of the compressor to which the air supply pipe is attached are determined. Power consumption calculating means for calculating the power consumption corresponding to the air leaked from the apparatus.
[0014]
In addition to calculating the leakage rate, the power consumption of the compressor corresponding to the actually leaked air can be calculated based on the leakage rate. Therefore, the degree of the air leak is calculated as an intuitive and easy-to-understand value.
[0015]
According to a fourth aspect of the present invention, in the air leak amount detecting device according to the third aspect, the waste power consumption calculating means can further calculate an amount of money corresponding to the waste power consumption. I have.
[0016]
Since the wasteful power consumption calculating means according to the third aspect can convert the wasteful power consumption into a monetary amount, it can more intuitively recognize how much energy saving is hindered compared to the third aspect. be able to.
[0017]
According to a fifth aspect of the present invention, there is provided an air leak amount detecting apparatus according to any one of the first to fourth aspects, wherein the pressure drop time in the first aspect and the air leaking time in the second aspect are provided. A display unit for displaying at least one of the rate, the amount of wasteful power consumption according to the third aspect, and the amount of money according to the fourth aspect.
[0018]
By displaying the pressure drop time, the air leak rate, the amount of wasteful power consumption based on the air leak, and the amount corresponding thereto, it is possible to confirm the degree of waste energy due to the air leak on the spot.
[0019]
An air leak detection device according to a sixth aspect of the present invention includes the air leak amount detection device according to any one of the first to fifth aspects, and an air flow rate of an air pipe to which the air leak amount detection device is attached. Is a flow meter that can measure
[0020]
Since the flow meter can not only measure the air flow supplied to the pipe but also accurately calculate the air leak amount, the flow meter itself is useful for detecting the leak amount of the air pipe and grasping the amount of wasted power, etc. Additional functions can be provided. In addition, since the air leak amount can be measured with one flow meter, there is no need to install a new measuring device such as a pressure gauge, which leads to a reduction in cost and installation work.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an air leak detection device according to a first embodiment of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 shows a compressor C and a part of an air pipe P connected thereto, and also shows a schematic block diagram of a flow meter R attached to an air pipe. The flow meter R is provided with a differential pressure type transmitter 1, measures the pressure near the upstream side and the pressure near the downstream side of the orifice S provided in a part of the air pipe P, and obtains the differential pressure to obtain the air in the air pipe. It measures the flow rate. Although only a part of the downstream air pipe P of the flow meter R is shown in FIG. 1, in an actual air supply device, for example, the air pipe P is arranged in the entire factory. An unillustrated portion of the air pipe P is branched innumerably, and each pipe end is connected to a desired position in a factory. As a result, the air from the compressor is supplied to all the working positions and the installation positions of the actuators in the factory.
[0023]
As shown in FIG. 1, the differential pressure type transmitter 1 is provided inside the differential pressure type transmitter as well as measuring the above-mentioned differential pressure with the differential pressure sensor 11 and calculating the air flow rate with the flow rate calculation unit 15. The pressure sensor 12 measures the air pressure in the air pipe, and the temperature sensor 13 provided in the differential pressure type transmitter compensates for the output drift of the differential pressure type transmitter. Therefore, the temperature of the air in the air pipe can be constantly measured by the temperature sensor 13. Then, the output of the air pressure and the air temperature detected by the differential pressure type transmitter 1 is sent to the pressure falling time measuring unit 16 and the pressure correcting unit 16a constituting the air leak detecting device 10, and the pressure drop having a correlation with the air leak amount is transmitted. Time is being sought. Further, a display device 14 is connected to the air leak detection device 10.
[0024]
Hereinafter, a method of detecting the amount of air leak using the above-described differential pressure type transmitter 1 will be specifically described.
[0025]
The air leak detection device 10 according to the first embodiment of the present invention is integrally provided inside the above differential pressure transmitter, and the operator selects the air leak detection mode as shown in the flowchart of FIG. The air leak amount can be measured in the mode (step S1). Further, apart from this manual mode, the pressure sensor 12 constantly monitors the air pressure, and forcibly measures the air leak amount when the pressure drops to a certain pressure without shifting to the air leak amount detection mode. (Step S1a).
[0026]
The processing steps when the air leak amount detection mode is set will be described below. First, when the operator selects the air leak amount detection mode (step S1), the pressure drop time measuring unit 16 sends a close signal to a fully closed valve in an air pipe (not shown) and sends a compressor stop signal to the compressor (step S1). S2). Thus, if there is a certain amount of air leak from the air pipe, the pressure in the air pipe gradually decreases.
[0027]
Then, the pressure sensor 12 detects that the air pressure in the air pipe drops and reaches the pressure P1. When the pressure sensor 12 detects that the air pressure has dropped to the pressure P1, an air leak amount detection step is started. Specifically, the time when the pressure P1 is detected is stored (step S3). The pressure P1 is a fixed value set in advance.
[0028]
On the other hand, the pressure sensor 12 constantly monitors the air pressure in the air pipe regardless of the operating state of the compressor C (step S1a). Then, even when the air pressure in the pipe drops to the pressure P1 even though the manual air leak amount detection mode is not selected, the time at this point is stored (step S3).
[0029]
After the air pressure has decreased to the pressure P1, the pressure further decreases from the time when the air pressure has decreased to the pressure P1, and the time required for the air pressure to decrease from the pressure P1 to the pressure P2 lower than this is measured (step). S5). Here, the pressure P2 is also a preset fixed value.
[0030]
During the period from step S3 to step S5, the air temperature of the air pipe when the pressure P1 is reached is measured by the temperature sensor 13, and in the measurement of the air pressure after the pressure P1 is reached, the pressure is measured as follows. The pressure fluctuation due to only the temperature change from the point of detection of P1 is canceled (step S4). The principle of this cancellation (compensation) is as follows.
[0031]
The gas in the pipe is constant PV / T according to Boyle-Charles law. Here, assuming that there is no leakage from the pipe (V = constant), assuming that the temperature is reduced to ２, the pressure P ′ is also reduced to 'because P ′ = P × １ ／. . If the temperature is not measured during steps S3 to S5, this pressure difference is erroneously detected as air leakage.
[0032]
Here, as an example, a specific temperature rise in the pipe is as follows.
[0033]
Assume that the temperature at the pressure P1 is 25 ° C. Thereafter, assuming that the temperature in the piping has risen to 35 ° C. due to the stop of the air conditioning in the factory, the pressure P ′ obtained by correcting the temperature is as follows.
P ′ = P1 × (25 + 273) / ((25 + 273) +10)
Therefore, P ′ ≒ P1 × 0.968
You can ask. In other words, if the temperature is not corrected,
((25 + 273) +10) / (25 + 273) = 1.034 times the pressure has increased, and it is not possible to detect leakage or minute leakage.
[0034]
However, the pressure correction unit 16a in the present embodiment corrects the measured pressure based on the temperature change according to Boyle-Charles law. In the above example, the pressure value excluding the influence of the temperature can be obtained by correcting the measured pressure by twice. This makes it possible to measure the pressure more accurately and to detect a minute leak.
[0035]
That is, in the present embodiment, the temperature when the pressure sensor 12 detects the pressure P1 is defined as T1. Thereafter, the pressure sensor 12 detects the pressure value P ′ until the pressure P2 is detected, and the temperature at the time of this detection is T1 + ΔT. In this case, the relationship between the temperature change amount ΔT and the pressure P at which the temperature change amount ΔT is canceled is obtained as follows.
[0036]
P / T1 = P '/ (T1 + ΔT)
Therefore, the pressure P at which the temperature change ΔT has been canceled is as follows.
[0037]
P = P '× T1 / (T1 + ΔT)
In this manner, during steps S3 to S5, the pressure measurement is performed while canceling the pressure change due to only the air temperature change measured by the temperature sensor 13 among the pressure values measured by the pressure sensor 12. . Then, similarly, the time from the detection of the pressure P1 to the detection of the pressure P2 obtained by the above measurement is measured in step S5, and the above-mentioned time is defined as the pressure falling time related only to the air leak amount in step S6.
[0038]
In FIG. 3, the vertical axis indicates the pressure in the pipe described above, and the horizontal axis indicates the time axis accompanying the decrease in air pressure. In the section A in the time, it can be seen that the pressure in the pipe is almost constant and the pressure hunts within a certain range. Then, in (1), when the operator selects the air leak amount detection mode, the piping valve is closed and the compressor is stopped, so that in section B, the pressure gradually decreases due to the air leakage from the piping. Then, in (2), the time when the air pressure reaches P1 and further falls from this point to the pressure P2 is measured.
[0039]
In general, it takes a considerably long time, for example, several hours, after the compressor is stopped until the pressure in the air pipe drops over P2, and manual mode selection for detecting such an air leak amount is generally required. Is often performed, for example, immediately after the plant stops operating. Therefore, for example, in summer, when such a long time as several hours elapses, the ambient temperature in the factory rapidly rises during this time due to the stoppage of the cooling system in the factory. Along with this, the temperature inside the air pipe also rises. When the temperature in the air pipe rises as time elapses, as shown by the one-dot chain line in FIG. 3 during the measurement time, although the state characteristic of the air leak is originally indicated by the solid line in FIG. The relationship between the time in the air piping and the pressure change will change.
[0040]
As a result, if the pressure measurement is performed without canceling the pressure fluctuation due to the change in the air temperature, the pressure drop time is essentially the time from the time of detecting the pressure P1 to the time of detecting the pressure P2 based on the pressure drop curve shown by the solid line in FIG. Although it should be measured as t, the time t ′ from the time of detecting the pressure P1 to the time of detecting the pressure P2 is measured to be longer based on the pressure drop curve indicated by the one-dot chain line in FIG. That is, the air leak amount is erroneously detected as being smaller than the air leak amount that should be obtained when there is no temperature change.
[0041]
On the other hand, for example, in winter, when the air leak detection mode is selected at the same time as the operation of the factory equipment is stopped, the ambient temperature in the factory is suddenly reduced due to the stop of the heating equipment simultaneously with the stop of the factory equipment, contrary to the case of the summer described above. The air temperature in the air pipe decreases accordingly. Therefore, if the pressure measurement is performed without canceling the pressure fluctuation due to the change in the air temperature, the slope is larger than the change in which the air pressure decreases when there is no temperature change as shown by the two-dot chain line in FIG. As a result, the time taken for the pressure P1 to drop from the pressure P1 to the pressure P2 is measured ignoring such a temperature change. When the measurement time is t ″, the pressure P2 is detected when the pressure P1 is detected based on the pressure drop when there is no temperature change. The measurement is made shorter than the time t until the detection, that is, the air leak amount is erroneously detected more than the actual air leak amount.
[0042]
However, in the present invention, as described above, when the pressure sensor measures the air pressure P1, the variation ΔT with respect to the temperature T at this time is always measured. Then, the change in the pressure based only on this temperature change is canceled based on the above-described Boyle-Charles law, and after the pressure sensor detects the pressure P1, the pressure is detected at the same temperature as when the pressure P1 was detected. Correct the measured pressure to the pressure. As a result, the degree of pressure decrease in the pipe depends only on the amount of air leak in the pipe, and is not affected by a change in air temperature. That is, the pressure drop curve does not shift from the solid line shown in FIG. 3 to the one-dot chain line or the two-dot chain line due to the change in the air temperature. Accordingly, it is possible to determine that the amount of air leak from the air pipe is small when the measurement time t is large regardless of the change in the air temperature, and that the amount of leak from the air pipe is large when the measurement time t is small.
[0043]
As described above, the air leak amount detection device according to the first embodiment of the present invention eliminates the influence of the air temperature change at the time of the pressure measurement due to the temperature change caused by the fact that the air is a compressible fluid, and reduces the pressure from the pressure P1 to the pressure P1. The measurement time up to P2 can be calculated as a measurement time corresponding to only the amount of air leak in the pipe. Then, the time thus measured can be sequentially displayed on the display device 14 and confirmed. Alternatively, data may be sent to a company that manages energy saving at each factory via communication means (telephone line) without providing the display device 14. If the measurement time corresponding to such a pressure drop is displayed on the display device 14, the worker at the site can grasp the amount of air leak in the factory on the spot and raise the awareness of energy saving. Can be.
[0044]
Subsequently, an air leak amount detection device according to a second embodiment of the present invention will be described. Note that the same components as those in the first embodiment are denoted by the corresponding reference numerals, and detailed description is omitted.
[0045]
The air leak detection device 20 according to the second embodiment of the present invention is provided integrally with a differential pressure transmitter 2 installed in an air pipe P as shown in FIG.
[0046]
That is, as in the case of the first embodiment, the differential pressure type transmitter 2 includes a differential pressure sensor 21 for measuring the differential pressure on the upstream side and the downstream side of the orifice S, and a pressure sensor 22 for measuring the air pressure in the pipe. , And a temperature sensor 23 for measuring the air temperature in the pipe. The outputs of these sensors are input to a flow rate calculation unit 25 to measure the air flow rate in the pipe.
[0047]
The air leak amount detecting device 20 includes a pressure change time measuring unit 26, a pressure correcting unit 26a, an air leak rate calculating unit 27, a waste power consumption calculating unit 28, and a waste amount calculating unit 29 therein. These contents can be displayed.
[0048]
Here, the output values of the pressure sensor 22 and the temperature sensor 23 are also used in the air leak amount detection device 20. That is, the air pressure value in the pipe detected by the pressure sensor 22 is sent to the air leak amount detection device 20. Further, the air temperature in the pipe detected by the temperature sensor 23 is also sent to the air leak amount detecting device 20. The air leak rate calculating section 27 calculates the air leak rate based on the calculation results of the pressure change time measuring section 26 and the pressure correcting section 26a, and the waste power consumption calculating section 28 calculates the waste power consumption based on the air leak rate. Is calculated, and the waste amount calculator 29 calculates the amount of money corresponding to the wasted power. Then, the air leak rate, the wasted power consumption, and the amount of money corresponding to the wasted power consumption are displayed on the display device 24. It is to be noted that, as shown in FIG. 4, without providing the display device 24 or together with the display device 24, the air leak rate, the amount of wasted power consumption, and the amount corresponding to the air leak rate, the telephone line as in the first embodiment. May be transmitted to a remote place via the Internet.
[0049]
Subsequently, a method of calculating an air leak rate by the air leak amount detection device 20 will be described. As can be seen from the flowcharts shown in FIGS. 5 and 6, first, the compressor C is activated to supply air to the air pipe P in the factory (step S11). With the activation of the compressor C, the pressure in the air pipe rapidly rises as shown in FIG. Here, the air leak amount detection device 20 monitors whether or not the value of the pressure sensor increases to P2, and stores the time when the air pressure reaches P2 (step S12). After the air pressure reaches P2, the air pressure measured thereafter is corrected to the air pressure converted to this temperature based on the air temperature T2 at this time (step S13). Note that the pressure P2 is a preset fixed value. That is, the air pressure after the detection of the air pressure T2 is obtained by the following equation, where P is a pressure value obtained by canceling the temperature change from the pressure P "specifically measured by the pressure sensor.
[0050]
P = P ″ × T2 / (T2 + ΔT)
Here, ΔT is a deviation amount between the temperature at the time of detecting the pressure P2 measured by the temperature sensor and the temperature at the time of the subsequent pressure measurement. Then, the time when the pressure P reaches the pressure P1 larger than the predetermined pressure P2 is measured, and the pressure rise time t1 from when the pressure P2 is reached to when the pressure P rises to the pressure P1 (see FIG. 7). ) Is calculated (step S14).
[0051]
Thereafter, the air pressure P is kept at a substantially constant level exceeding the pressure P1 while repeating hunting (not particularly shown in FIG. 7) of a small amplitude as shown in FIG. 3 in the first embodiment described above with the operation of the air compressor. Stabilize. Subsequently, when the operator selects the air leak amount detection mode (Step S15), all the closing valves in the air piping are closed, the compressor C is stopped (Step S16), and the pressure in the air piping starts to decrease. As described above, the air leak amount detection mode is selected in the manual mode similar to the first embodiment (step S15), or the pressure sensor 22 constantly detects the pressure in the air pipe (step S17). The pressure sensor 22 detects that the internal pressure decreases to the pressure P1 (step S18).
[0052]
Then, when the pressure sensor 22 detects that the pressure in the air pipe has reached P1, the time at which the pressure reaches P1 is stored in the same manner as in the above-described first embodiment (step S18).
[0053]
Subsequently, from this point on, the pressure value measured by the pressure sensor 22 is calculated by converting it into a pressure value in which only the variation due to the air temperature is canceled by the same method as in the first embodiment (step S19). That is, assuming that the temperature at the pressure P1 is T1, the pressure P in the air pipe in which the change ΔT in the air temperature is canceled with respect to the detected pressure P ′ of the pressure sensor 22 is expressed by the following equation.
[0054]
P = P '× T1 / (T1 + ΔT)
The time from when the corrected pressure value P decreases to the pressure P2 after the detection of the pressure P1 is measured, and this time is calculated as a pressure decrease time t2 (see FIG. 7) (step S20).
[0055]
Subsequently, the air leak rate calculation unit 27 calculates the air leak rate Lp based on the pressure rise time t1 and the pressure fall time t2 calculated as described above (step S21). The air leakage rate Lp is obtained by the following equation.
[0056]
Lp = (t1 / (t1 + t2)) × 100 (%)
As described above, the air leak amount detection device 20 according to the second embodiment of the present invention uses the relative relationship between the air pressure rise time t1 and the air pressure fall time t2 (the pressure rise time t1 and the pressure fall time t2). (The ratio of the pressure rise time t1 to the sum of the above). That is, when the amount of air leak in the pipe is small, the value of t2 increases and the air leak rate Lp decreases. Conversely, if the amount of air leak in the pipe is large, the value of t2 decreases and the air leak rate Lp increases. Further, since the air leak rate Lp is calculated only by the value between the pressure rise time and the pressure fall time, it is always possible to calculate the correct air leak rate Lp even when the capacity in the air pipe changes. There is a merit that can be.
[0057]
In addition, the air leak rate is expressed by the air leak rate Lp. If the air leak rate Lp is large, it can be determined that the air leak quantity is large, and if the air leak rate Lp is small, it can be determined that the air leak rate is small. By displaying the information on the display 24, it is possible to help the maintenance and inspection of the site operator.
[0058]
Subsequently, by multiplying the energy consumption (W) of the compressor per unit time and the operating time (T) based on the above-described air leakage rate Lp, a waste power consumption Le corresponding to the air leakage amount is calculated ( Step S22). The wasted power consumption Le can be obtained by the following equation.
[0059]
Le = W × T × Lp / 100 (kWh)
When the waste power consumption Le obtained in this manner is displayed on the display device 24 in the same manner as the above-described air leakage rate Lp, it can be grasped as an intuitive and easy-to-understand value for the operator.
[0060]
In addition, by multiplying the amount of waste power consumption by the amount of power (Cy (yen / kWh)), a value converted into an amount corresponding to the amount of waste power consumption can be obtained (step S23). That is, the amount of money Co can be obtained by the following equation.
[0061]
Co = Cy × Le (yen)
By displaying this money amount, the air leakage rate Lp, and the waste power consumption Le on the display device 24 as necessary, it can be used for maintenance inspection in the factory and confirmation of the degree of energy saving (step S24). ).
[0062]
The data of the air leakage rate Lp, the wasted power consumption Le, and the amount Co corresponding to the wasted power consumption Le are transmitted to a factory energy management company using a telephone line in the same manner as in the first embodiment. You may send it. Thus, for example, a change in the air leak rate Lp for each factory operation day can be grasped as a trend, and energy management becomes easy. In addition, when the air leak suddenly increases, it is possible to respond promptly assuming that some trouble has occurred. It is also possible to calculate the amount of money based on the waste power consumption Le, for example, on a monthly or yearly basis.
[0063]
In the above-described embodiment, the air leak amount detecting devices 10 and 20 have been described as being provided integrally with the differential pressure type transmitters 1 and 2. However, the present invention is not limited to this configuration. May be provided separately.
[0064]
Further, in the air leak amount detection device 20 according to the second embodiment, it is not always necessary to calculate the waste power consumption Le and the money amount Co corresponding thereto, and only the air leak rate Lp may be calculated. good. In addition, the air leak amount detection devices 10 and 20 do not necessarily need to include the display devices 14 and 24, and may include only the data transmission unit using the above-described telephone line instead of the display devices 14 and 24.
[0065]
In the above-described embodiment, when there is a change in the temperature of the air, the pressures P1 and P2, which are the thresholds, are dealt with by canceling only the temperature change of the pressure value that is sequentially measured as a preset fixed value. Unlike the pressure P1 at the time of pressure increase and the pressure P2 at the time of pressure decrease, the pressure corresponding to the change is canceled according to the temperature change, and the pressure is measured successively. Is also good. That is, for example, when measuring the pressure fall time, assuming that after the pressure sensors 12 and 22 detect the pressure P1, the amount of temperature change from the time of detecting the pressure P1 at the time of detecting the pressure P2 is ΔT, the threshold P2 is set to the following P2 ′. To be corrected.
[0066]
P2 ′ = P2 × (T1 + ΔT) / T1
In contrast to this, when measuring the pressure rise time, assuming that after the pressure sensors 12 and 22 detect the pressure P2, the amount of temperature change from the time of detecting the pressure P2 at the time of detecting the pressure P1 is ΔT, the threshold P1 is set to the following P1. To '.
[0067]
P1 ′ = P1 × (T2 + ΔT) / T2
【The invention's effect】
As described above, the air leak amount detection device according to the present invention measures the pressure drop time from the first pressure value to the second pressure value using the pressure drop time measurement means. After the detection, the air pressure change based on only the air temperature change is canceled. Therefore, even if there is a change in the temperature of the air within the pressure falling time measurement time, the measured pressure is not affected, and the accurate air leak amount can always be obtained by converting it into the pressure falling time.
[0068]
In the air leak amount detecting device according to the second aspect of the present invention, similarly to the first aspect, the air pressure shift caused by only the temperature change of the air within the pressure rising time or the pressure falling time by the pressure correcting means. Can be canceled, and an accurate air leakage rate can be calculated.
[0069]
Further, the pressure rise time from the second pressure value to the first pressure value when the pressure rises when the compressor is started and the pressure fall time from the first pressure value to the second pressure value when the pressure falls are relatively determined. Are compared. This makes it possible to always calculate an accurate air leakage rate regardless of the type and arrangement of the air pipe to which the air leak amount detection device is attached.
[0070]
Further, the air leak amount detecting device according to the third aspect of the present invention can not only calculate the leak rate, but also can calculate the power consumption of the compressor corresponding to the actually leaked air based on the leak rate. In addition, the degree of the air leak amount can be calculated as an intuitive and easy-to-understand value.
[0071]
Also, in the air leak amount detecting device according to claim 4 of the present invention, the waste power consumption calculating means according to claim 3 can calculate the amount of waste power consumption by converting the amount of waste power consumption into money. In comparison, it is possible to more intuitively recognize how much energy saving is hindered.
[0072]
In addition, the air leak amount detecting device according to claim 5 of the present invention can display a pressure drop time, an air leak rate, a wasteful power consumption amount based on the air leak, and an amount corresponding thereto. This makes it possible to check on the spot the degree of wasted energy caused by air leaks.
[0073]
In the air leak amount detecting device according to the sixth aspect of the present invention, the flow meter can not only simply measure the flow rate of the air supplied to the pipe, but also accurately calculate the air leak amount. It is possible to provide a useful additional function to the air pipe itself, such as detecting a leak amount of the air pipe and grasping a waste power amount. In addition, since the air leak amount can be measured with one flow meter, there is no need to install a new measuring device such as a pressure gauge, which leads to a reduction in cost and installation work.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a state in which a flow meter provided with an air leak amount detection device according to a first embodiment of the present invention is installed in an air pipe.
FIG. 2 is a flowchart showing a procedure for detecting an air leak amount in a pipe using the air leak amount detecting device of FIG. 1;
FIG. 3 is a diagram illustrating a method of measuring a pressure drop time in a pipe based on the air leak amount detection device of FIG. 1;
FIG. 4 is a schematic configuration diagram illustrating a state in which a flow meter provided with an air leak amount detection device according to a second embodiment of the present invention is installed in an air pipe.
FIG. 5 is a flowchart for obtaining an air leak rate, a wasteful power consumption, and a money amount corresponding to the wasteful power consumption using the air leak amount detection device of FIG. 4;
FIG. 6 is a flowchart following FIG. 5;
FIG. 7 is a diagram illustrating a method of detecting an air leak amount using the air leak amount detecting device according to the second embodiment.
[Explanation of symbols]
1 Differential pressure transmitter
2 Differential pressure transmitter
10 Air leak detection device
11 Differential pressure sensor
12 Pressure sensor
13 Temperature sensor
14 Display device
15 Flow rate calculator
16 Pressure fall time measurement section
16a Pressure compensator
20 Air leak detector
21 Differential pressure sensor
22 Pressure sensor
23 Temperature sensor
24 Display device
25 Flow rate calculator
26 Pressure change time measurement section
26a Pressure compensator
27 Air Leakage Rate Calculator
28 wasted power consumption calculator
29 Waste amount calculator
C compressor
P Air piping
R flow meter
S orifice
Lp Air leak rate
Le Wasted power consumption
Co waste amount
Cy Amount for electricity

Claims (6)

An air leak amount detection device used for a power air supply facility including an air supply compressor and an air supply pipe connected to the compressor to supply air to a desired position,
A pressure sensor for measuring the air pressure in the air supply pipe,
A temperature sensor for measuring the air temperature in the air supply pipe,
Pressure falling time measuring means for measuring a pressure falling time from a time when the pressure value by the pressure sensor falls to the first pressure value to a time when the pressure value falls to a second pressure value lower than the first pressure value. ,
The pressure falling time measuring means is configured to detect only the air temperature change from the time of the first pressure value detection until the second pressure value detection after the first pressure value detection based on the output of the temperature sensor. An air leak amount detecting device comprising a pressure correcting means for canceling an accompanying air pressure change. An air leak amount detection device used for a power air supply facility including an air supply compressor and an air supply pipe connected to the compressor to supply air to a desired position,
A pressure sensor for measuring the air pressure in the air supply pipe,
A temperature sensor for measuring the air temperature in the air supply pipe,
The pressure sensor measures a pressure drop time from a point in time when the pressure value drops to a first pressure value to a point in time when the pressure value drops to a second pressure value lower than the first pressure value. Pressure change time measuring means for measuring a pressure rise time from a time when the pressure value rises to a first pressure value to a time point when the pressure value rises to a first pressure value,
The pressure change time measuring means is configured to detect only the air temperature change from the time of the first pressure value detection until the second pressure value is detected after the first pressure value is detected by the pressure sensor at the time of the pressure drop. In addition to canceling the air pressure change, the air pressure change from the time of the second pressure value detection to the first pressure value detection after the second pressure value is detected by the pressure sensor at the time of the pressure rise is limited to only the air temperature change amount. Having a pressure correction means for canceling the accompanying air pressure change,
And an air leak rate calculating means for calculating an air leak rate from a relative relationship between the pressure rise time and the pressure fall time measured by the pressure change time measuring means. A power consumption calculator that calculates a power consumption corresponding to the leaked air from the air leakage rate and an energy consumption per unit time of a compressor to which the air supply pipe is attached. The air leak amount detection device according to claim 2, wherein 4. The air leak amount detecting device according to claim 3, wherein the waste power consumption calculating means can further calculate a money amount corresponding to the waste power consumption. A display means for displaying at least one of the pressure drop time in claim 1, the air leakage rate in claim 2, the wasteful power consumption in claim 3, and the amount of money in claim 4. The air leak amount detection device according to any one of claims 1 to 4. A flow meter comprising the air leak amount detecting device according to any one of claims 1 to 5, and capable of measuring an air flow rate of an air supply pipe to which the air leak amount detecting device is attached.

Images