Steam flow rate calculation device, heating system, and data acquisition method

Abstract

To provide a steam flow rate calculation device capable of calculating a steam flow rate in a system for supplying steam to a supply object accompanied by steam condensation via a proportional valve.SOLUTION: A device for sequentially calculating a mass flow rate of steam in a steam supply system that supplies steam from a steam supply source to a supply target involving steam condensation via a proportional valve, the device including a monitoring unit that monitors a first pressure value that is a pressure value of the steam on a preceding stage side of the proportional valve, a second pressure value that is a pressure value of the steam on a subsequent stage side of the proportional valve, and a Cv value of the proportional valve, and a storage unit that stores correction coefficients determined for a plurality of different Cv values in the proportional valve, A mass flow Q is calculated based on an expression of Q = K * Cv * {dP (P1 + P2)} ^ 0.5. Where P1 is the first pressure at that time, P2 is the second pressure at that time, dP is the difference between P1 and P2, Cv is the Cv value of the proportional value at that time, and K is a correction coefficient corresponding to the Cv.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a steam flow rate calculation device, a heating system including the same, and a data acquisition method. [Background technology]

[0002] Conventionally, heating systems that use steam as a heat source for heating have been proposed. For example, Patent Document 1 discloses a food heat sterilization treatment device that supplies steam to a heat exchanger to heat treatment water and uses this treatment water to heat and sterilize the food. In such a system, by configuring the steam flow rate to be controlled by a proportional valve, it becomes possible to finely adjust the intensity of heating.

[0003] In the above-mentioned systems, it is desirable to be able to monitor the steam flow rate in order to understand the amount of energy consumed and lost and to achieve energy savings. A common approach to monitoring the steam flow rate is to install a steam flow meter in the steam flow path. However, steam flow meters are generally expensive, and installing a new steam flow meter requires work that involves cutting the piping. For these reasons, installing a steam flow meter in the above-mentioned systems is often difficult.

[0004] On the other hand, in addition to using a steam flow meter, a known method for monitoring steam flow is to calculate the steam flow rate from the differential pressure before and after a valve installed in the steam flow path. More specifically, the steam flow rate Q can be calculated using the following formula (A) or (B), where the Cv value (capacity coefficient) of the valve is Cv, the pressure on the primary side of the valve is P1, the pressure on the secondary side of the valve is P2, and the differential pressure between the primary and secondary sides of the valve is dP.

[0005] (A) When dP<0.5×P1, Q=0.138×k1×Cv×{dP(P1+P2)}^0.5 (B) When dP≧0.5×P1, Q=0.12×k2×Cv×P1 Note that k1 and k2 above are correction coefficients. The commonly known formulas are (A) and (B) which do not have such correction coefficients, but in actual operation, formula (A) or (B) is used, which has a predetermined correction coefficient that matches the measurement target, such as the part shape and flow velocity range. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4229420 Summary of the Invention [Problem to be solved by the invention]

[0007] When a valve with a fixed Cv value that is not a proportional valve is used as the valve described above, it is possible to calculate the steam flow rate using the above formula (A) or (B) by applying a set of correction coefficients, k1 and k2. However, when a proportional valve is used, it is not possible to calculate the steam flow rate in the same way as when a valve with a fixed Cv value is used. This is because the range (fluctuation range) of the flow rate passing through the proportional valve is wide due to changes in the valve opening, and the shape of the proportional valve's flow path changes depending on the valve opening. Furthermore, steam condenses in the heat exchanger (the target of steam supply) downstream of the proportional valve, causing a pressure drop due to a phase change.

[0008] The specific situation when a proportional valve is used will be described below using, as an example, the results of an experiment conducted using a heating system 100 shown in Fig. 6. First, in the heating system 100 shown in Fig. 6, a steam supply line 101 is provided extending from a steam supply source 102, passing through a pressure reducing valve 103, a steam flow meter 104, a proportional valve 105, and a heat exchanger 106 in that order. Also, a heat medium circulation path 107 is provided that passes through the heat exchanger 106 and a retort pot 110a in a retort sterilizer 110. Also, a first pressure sensor 108a is provided between the steam flow meter 104 and the proportional valve 105, and a second pressure sensor 108b is provided between the proportional valve 105 and the heat exchanger 106.

[0009] In heating system 100, steam supplied from steam supply source 102 to steam supply line 101 enters heat exchanger 106 via proportional valve 105 and undergoes heat exchange with a heat medium in circulation path 107. This makes it possible to use the heat of the steam to heat retort pot 110a. In actual use, the valve aperture of proportional valve 105 is automatically adjusted so that the temperature of retort pot 110a is appropriate, but for purposes of experimentation, the valve aperture of proportional valve 105 was set to any desired value.

[0010] Fig. 7 is a graph showing the relationship between the differential pressure and the steam flow rate measured using the heating system 100 shown in Fig. 6. Note that the differential pressure here is the difference between the detection value of the first pressure sensor 108a and the detection value of the second pressure sensor 108b, and the steam flow rate is the measurement value of the steam flow meter 104. The colored plots shown in Fig. 7 show the relationship based on the measurement results in the process (process 1) of increasing the valve opening of the proportional valve 105 from 0% to 100%, and the open plots show the relationship based on the measurement results in the process (process 2) of decreasing the valve opening of the proportional valve 105 from 100% to 0%.

[0011] However, plotting is omitted when the valve opening of proportional valve 105 is 20% or less, because the steam flow rate was below the lower measurement limit of steam flow meter 104. Generally, for proportional valves of the same configuration, there is a one-to-one correspondence between the valve opening and the Cv value, and if the valve opening is specified, the Cv value can also be specified. Figure 7 shows the valve opening of proportional valve 105 as well as the corresponding Cv value.

[0012] In process 1, the temperature on the secondary side of heat exchanger 106 is low, so steam condenses actively, whereas in process 2, the temperature on the secondary side of heat exchanger 106 is high, so steam condenses slowly. For this reason, when comparing process 1 and process 2, the relationship between differential pressure and steam flow rate is significantly different even with the same valve opening (Cv value). In this way, when the relationship between differential pressure and steam flow rate cannot be uniquely determined, it is difficult to calculate the steam flow rate using the method described above.

[0013] In view of the above-mentioned problems, the present invention has an object to provide a steam flow rate calculation device that can calculate a steam flow rate in a system that supplies steam to a supply target involving steam condensation via a proportional valve. Another object of the present invention is to provide a heating system using the steam flow rate calculation device, and a method for acquiring data used in the steam flow rate calculation device. [Means for solving the problem]

[0014] A steam flow rate calculation device according to the present invention is a steam flow rate calculation device for sequentially calculating a mass flow rate of steam in a steam supply system that supplies steam from a steam supply source via a proportional valve to a supply target that involves steam condensation, and includes: a monitoring unit that monitors a first pressure value that is a pressure value of the steam on an upstream side of the proportional valve, a second pressure value that is a pressure value of the steam on a downstream side of the proportional valve, and a Cv value of the proportional valve; and a memory unit that stores correction coefficients determined for each of a plurality of different Cv values ​​of the proportional valve, The mass flow rate (referred to as Q) is calculated based on the following first formula. Q=K×Cv×{dP(P1+P2)}^0.5 ···Equation 1 where P1 is the first pressure value at that time, P2 is the second pressure value at that time, dP is the difference between P1 and P2, Cv is the Cv value of the proportional valve at that time, and K is the correction coefficient corresponding to Cv.

[0015] According to this configuration, it is possible to calculate the steam flow rate in a system that supplies steam via a proportional valve to a supply target that involves steam condensation.

[0016] More specifically, the above configuration may be configured such that the monitoring unit acquires detection information from a pressure sensor disposed between the steam supply source and the proportional valve as information on the first pressure value, and acquires detection information from a pressure sensor disposed between the proportional valve and the supply target as information on the second pressure value.

[0017] More specifically, the object to be heated may be the high-temperature side of a heat exchanger. A heating system according to the present invention includes the steam flow rate calculation device of the above configuration and the steam supply system, and supplies the heat medium that has exchanged heat with the steam in the heat exchanger to the object to be heated, and controls the aperture of the proportional valve based on the temperature detected in the object to be heated. In this configuration, the object to be heated may be a retort oven.

[0018] Furthermore, a data acquisition method according to the present invention is a data acquisition method for obtaining data on each of the correction coefficients used in the steam flow rate calculation device having the above-described configuration, using a system with a flow meter, wherein the system with a flow meter includes a corresponding proportional valve corresponding to the proportional valve, a corresponding supply target corresponding to the supply target, and a steam flow meter that measures a mass flow rate of steam, and is configured to perform a supply operation of supplying steam from a steam supply source to the corresponding supply target via the steam flow meter and the corresponding proportional valve in that order, and the method comprises sequentially setting the Cv value of the corresponding proportional valve to a plurality of different values ​​in the system with a flow meter, and for each setting, using the measured value of the steam flow meter when the supply operation is performed as Q and calculating the value of K based on the first equation as the correction coefficient corresponding to the Cv value at that time. [Effects of the Invention]

[0019] The steam flow rate calculation device according to the present invention makes it possible to calculate the steam flow rate in a system that supplies steam to a supply target involving steam condensation via a proportional valve. [Brief explanation of the drawings]

[0020] [Figure 1] 10 is a graph showing the measurement results of each item in a confirmation experiment related to this embodiment. [Figure 2] 10 is a graph showing the measurement results of each item in a confirmation experiment related to this embodiment. [Figure 3] 10 is a graph showing a regression curve and experimental results regarding the relationship between steam flow rate and differential pressure in this embodiment. [Figure 4]1 is a schematic configuration diagram of a heating system according to an embodiment of the present invention. [Figure 5] 1 is a schematic configuration diagram of a system with a flow meter according to an embodiment of the present invention. [Figure 6] FIG. 1 is a schematic diagram of an example of a heating system in which a proportional valve is used. [Figure 7] 7 is a graph showing the relationship between the differential pressure and the steam flow rate measured using the heating system shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0022] 1. New method for calculating steam flow rate First, a new calculation method for the steam flow rate (steam mass flow rate) employed in this embodiment will be described. As mentioned above, in a system that supplies steam to a supply target involving steam condensation via a proportional valve, it is not possible to properly calculate the steam flow rate using equation (A) or (B) even if a set of correction coefficients k1 and k2 is applied. Therefore, it is difficult to grasp the steam flow rate unless a steam flow meter is installed, as in the system illustrated in Figure 6.

[0023] To solve this problem, the applicant has repeatedly studied and considered a method for properly calculating the steam flow rate even when a proportional valve is used. As a result, the applicant has discovered a new calculation method in which the correction coefficients k1 and k2 are set for each proportional valve opening (Cv value), and then the steam flow rate is calculated using equation (A) or (B), and has decided to verify the effectiveness of this calculation method.

[0024] As a confirmatory experiment for this verification, measurements were carried out for each item using a heating system 100 configured as shown in Fig. 6. More specifically, the valve opening of the proportional valve 105 was set to various values ​​in 10% increments, and for each setting, the steam flow rate, pressure value P1 on the primary side of the proportional valve, pressure value P2 on the secondary side of the proportional valve, differential pressure dP, and temperature inside the bed (temperature of the retort vessel 110a) were measured while the retort sterilizer 110 was operating.

[0025] The steam flow rate was measured using the steam flow meter 104. The pressure value P1 on the primary side of the proportional valve was measured using the value detected by the first pressure sensor 108a, and the pressure value P2 on the secondary side of the proportional valve was measured using the value detected by the second pressure sensor 108b. The differential pressure dP was measured using the difference between the pressure values ​​P1 and P2. The temperature inside the bed was measured using the value detected by a temperature sensor (not shown) provided in the retort pot 110a.

[0026] Graphs (a) to (h) in Figures 1 and 2 show the measurement results of each item in the above confirmation experiment for each valve opening of proportional valve 105. However, cases where the valve opening of proportional valve 105 was 20% or less have been omitted because the steam flow rate was below the lower measurement limit of steam flow meter 104. It is assumed that even during actual use, cases where the valve opening of proportional valve 105 is set to 20% or less are rare.

[0027] The timing of 0 s elapsed time in Figures 1 and 2 was determined to be the timing when a signal was output to control proportional valve 105 to the desired valve opening. After this timing, it took 1.2 to 2.5 s for proportional valve 105 to reach the desired valve opening. Furthermore, from the experimental results, it was determined that the response speed of steam flow meter 104 was approximately 20 s. From these results, it was determined that the 30 seconds after the signal to control the valve opening was output was an unsteady state, and data thereafter was used for analysis.

[0028] Next, using the aforementioned equations (A) and (B), a regression analysis was performed on the relationship between steam flow rate and differential pressure dP, and a graph was created showing the regression curve for this relationship and the experimental results. Examination of this graph revealed no significant differences between the regression curve and the experimental results, but the regression curve was discontinuous at the branch point between equations (A) and (B) (i.e., the position where differential pressure dP is 0.5 × P1). The existence of such a discontinuous point is undesirable for practical use in displaying calculated steam flow rate. Therefore, without using equation (B), a regression analysis was performed using equation (A) for all differential pressure dP intervals, and a graph was similarly created showing the regression curve for the relationship between steam flow rate and differential pressure dP and the experimental results.

[0029] Figure 3 shows a graph created in this way. In Figure 3, the regression curve is shown as a solid line, and the experimental results are shown as open plots (plots with a lighter color than the solid line). Figure 3 also shows the valve opening of proportional valve 105 and the value of correction coefficient k1 obtained by regression analysis. As shown in Figure 3, even when regression analysis was performed using equation (A) for all differential pressure dP ranges, no significant difference was observed between the regression curve and the experimental results; even under the largest error conditions, the difference was limited to about 5%. This confirms that a highly accurate regression curve can be obtained using only equation (A) without using equation (B).

[0030] It is presumed that the reason why a regression curve with good accuracy can be obtained using only equation (A) is that the factors that determine the differential pressure dP are related to the condensation of steam in the heat exchanger 106. The proper use of equation (A) and equation (B) based on the magnitude relationship between the differential pressure dP and the primary pressure can be applied when the difference in differential pressure dP is due only to the shape of a valve, orifice, etc. However, when the condensation of steam in the target to which the steam is supplied (heat exchanger 106) is involved, as in this confirmation experiment, it is thought that a regression curve with good accuracy can be obtained using only equation (A).

[0031] From the verification results explained above, it was confirmed that for a system that supplies steam to a supply target that involves steam condensation via a proportional valve, the steam flow rate can be calculated appropriately by setting the correction coefficient k1 for each proportional valve opening (Cv value) and then using equation (A). Note that this also applies when "0.138 x k1" in equation (A) is collectively defined as the correction coefficient K, and the correction coefficient K is set for each proportional valve opening (Cv value) and then using equation 1 described below.

[0032] 2. Steam flow rate calculation device and heating system Next, an example of a steam flow rate calculation device capable of calculating a steam flow rate using the above-described new calculation method and an example of a heating system provided with this device will be described. Fig. 4 shows a schematic configuration of a heating system 1 having a steam flow rate calculation device 40 according to this embodiment.

[0033] 4 includes a steam flow rate calculation device 10, a steam supply line 11, a steam supply source 12, a pressure reducing valve 13, a proportional valve 15, a heat exchanger 16, a circulation path 17, a first pressure sensor 18a, a second pressure sensor 18b, a temperature sensor 19, and a control device 20. The heating system 1 includes a steam supply system X that supplies steam from the steam supply source 12 via the proportional valve 15 to the high-temperature side of the heat exchanger 16 (a supply target involving steam condensation).

[0034] In the heating system 1, a steam supply line 11 is provided to extend from a steam supply source 12 via a pressure reducing valve 13, a proportional valve 15, and a heat exchanger 16 in this order. The steam supply source 12 is configured to send steam to the steam supply line 11, for example, directly from a boiler that generates steam or via a steam header or the like. A rear end of the steam supply line 11 is open to the outside. The steam supplied from the steam supply source 12 to the steam supply line 11 enters the high-temperature side of the heat exchanger 16 via the proportional valve 15, exchanges heat with the heat medium in the circulation path 17, and is then discharged to the outside from the rear end of the steam supply line 11.

[0035] The circulation path 17 is provided to pass through the low-temperature side of the heat exchanger 16 and the retort sterilizer 30, and is configured to circulate the heat medium. As a result, the heat medium that has exchanged heat with steam in the heat exchanger 16 can be supplied to the retort pot 30a (the object to be heated) of the retort sterilizer 30, and the object to be sterilized (such as food packed in a container) in the retort pot 30a can be heat-sterilized.

[0036] A first pressure sensor 18a that detects the steam pressure value at that position is disposed between the steam supply source 12 and proportional valve 15 (after the pressure reducing valve 13). A second pressure sensor 18b that detects the steam pressure value at that position is disposed between the proportional valve 15 and the heat exchanger 16. A temperature sensor 19 that detects the temperature of the retort kettle 30a is disposed in the retort sterilizer 30.

[0037] The control device 20 controls the valve aperture of the proportional valve 15 so that the detection value of the temperature sensor 19 becomes a predetermined appropriate value (or falls within a predetermined appropriate range). That is, when the temperature of the retort pot 30a is too low, the control device 20 increases the valve aperture of the proportional valve 15 to increase the amount of steam supplied to the heat exchanger 16, and when the temperature of the retort pot 30a is too high, the control device 20 decreases the valve aperture of the proportional valve 15 to decrease the amount of steam supplied to the heat exchanger 16. As described above, the heating system 1 heats the retort pot 30a (the object to be heated) by supplying the retort pot 30a (the object to be heated) with the heat medium that has exchanged heat with steam in the heat exchanger 16.

[0038] The steam flow rate calculation device 10 has a monitoring unit 10a and a storage unit 10b, and sequentially calculates the steam flow rate in the steam supply system X.

[0039] The monitoring unit 10a monitors the first pressure value P1, which is the detection value of the first pressure sensor 18a, the second pressure value P2, which is the detection value of the second pressure sensor 18b, and the Cv value of the proportional valve 15. This enables the steam flow rate calculation device 10 to acquire information on the first pressure value P1, the second pressure value P2, and the Cv value at predetermined time intervals T (for example, one second intervals).

[0040] The memory unit 10b stores each correction coefficient K (a coefficient equivalent to "0.138 x k1" in the above-mentioned formula (A)) determined for each of a plurality of different Cv values ​​in the proportional valve 15. The specific form of each correction coefficient K stored in the memory unit 10b is not particularly limited as long as it does not deviate from the spirit of the present invention. For example, each correction coefficient K may be stored in the form of the above-mentioned "0.138" and "k1" separately, and each correction coefficient K may be appropriately determined by multiplying these as needed. A method for acquiring data for each correction coefficient K to be stored in the memory unit 10b will be described later.

[0041] The steam flow rate calculation device 10 calculates the latest steam flow rate based on the following first formula at each time interval T during which information on the first pressure value P1, the second pressure value P2, and the Cv value can be acquired. Q=K×Cv×{dP(P1+P2)}^0.5 ···Equation 1 where Q is the steam flow rate at that time, P1 is the first pressure value at that time, P2 is the second pressure value at that time, dP is the difference between P1 and P2, Cv is the Cv value of proportional valve 15 at that time, and K is the correction coefficient K corresponding to Cv. Note that equation 1 corresponds to equation (A) already explained, where "0.138 x k1" is replaced with "K."

[0042] The steam flow rate calculation device 10 can sequentially calculate the steam flow rate in this manner. Note that a display device may be provided in the steam flow rate calculation device 10, and the sequentially calculated steam flow rate may be displayed on this display device in real time. Furthermore, data on the sequentially calculated steam flow rate may be recorded in the steam flow rate calculation device 10, or may be transmitted from the steam flow rate calculation device 10 to another communication device or the like. As described above, the steam flow rate calculation device 10 makes it possible to monitor the steam flow rate in the steam supply line 11 without the need to install a steam flow meter.

[0043] 3. How to obtain data for each correction coefficient Next, a data acquisition method for determining data of each correction coefficient K used in the steam flow rate calculation device 10 using a system with a flow meter will be described.

[0044] Fig. 5 shows a schematic diagram of an example of the configuration of a system 1x with a flow meter. The system 1x with a flow meter shown in this figure is a system that is capable of measuring the steam flow rate and of simulating the operation of supplying steam from the steam supply source 12 to a supply target via the proportional valve 15 in the steam supply system 1. The system 1x with a flow meter has basically the same configuration as the heating system 1 shown in Fig. 4, but is configured such that a steam flow meter 14 is provided at a predetermined position on the steam supply line 11 (a position between the pressure reducing valve 13 and the first pressure sensor 18a).

[0045] Similar to the steam supply system X in the heating system 1, the system 1x with a flow meter is capable of supplying steam from a steam supply source 12 to a heat exchanger 16 via a steam flow meter 14 and a proportional valve 15 in that order. Note that the system 1x with a flow meter does not require the installation of a steam flow calculation device 10, a temperature sensor 19, and a control device 20, and therefore these are omitted.

[0046] The elements of the steam supply line 11, steam supply source 12, pressure reducing valve 13, proportional valve 15 (one form of corresponding proportional valve), heat exchanger 16 (one form of corresponding supply target), circulation path 17, pressure sensors 18a and 18b, and retort sterilizer 30 in the system with flow meter 1x correspond to the elements with the same symbols in the heating system 1 including the steam supply system X shown in Figure 4. From the viewpoint of simulation accuracy, it is preferable that the corresponding elements in the system with flow meter 1x and the heating system 1 have the same or similar configurations and functions, but they may have different configurations and functions as long as it does not interfere with appropriate data acquisition.

[0047] In the flow meter-equipped system 1x, the Cv value of the proportional valve 15 is sequentially set to each of a plurality of different values, and for each setting, the measurement value of the steam flow meter 14 when the above supply operation is performed is set as Q, and the value of K calculated based on the first equation is set as the correction coefficient K corresponding to the Cv value at that time. This method makes it possible to obtain data on the correction coefficient K for each of the plurality of different Cv values.

[0048] As an example, to obtain data on the correction coefficients for each Cv value corresponding to every 10% valve opening of proportional valve 15, first set proportional valve 15 to 10% (i.e., set the Cv value of proportional valve 15 to the Cv value at 10% valve opening), and obtain the value of K calculated based on Equation 1 using Q as the measurement value of steam flow meter 14 when performing a supply operation at that time as the correction coefficient K corresponding to the Cv value at 10% valve opening. Note that the Cv value at 10% valve opening (the set Cv value) is substituted for Cv in Equation 1, and values ​​based on the detection results of pressure sensors 18a and 18b are substituted for dP and P1+P2. The correction coefficient K can be obtained based on Equation 1 if there is a set of data: the measurement value of steam flow meter 14, the set Cv value, the detection value of first pressure sensor 18a, and the detection value of second pressure sensor 18b.

[0049] Similarly, the correction coefficient K corresponding to each Cv value when the valve opening of the proportional valve 15 is 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% is calculated and obtained. In this way, data on the correction coefficient K for each Cv value corresponding to every 10% of the valve opening is obtained.

[0050] Although an example has been given here in which a correction coefficient for each Cv value corresponding to every 10% of valve opening is obtained, there are no particular limitations on how each Cv value is set, and for example, a correction coefficient for each Cv value corresponding to every 5% of valve opening may be obtained. Furthermore, based on data on the correction coefficient for each Cv value (for example, the correction coefficient for each Cv value corresponding to every 10% of valve opening) obtained using the flowmeter-equipped system 1x, data on more detailed approximation values ​​of the correction coefficient for each Cv value (for example, the correction coefficient for each Cv value corresponding to every 1% of valve opening) may be obtained by a technique such as linear interpolation.

[0051] Storing the data of the correction coefficient K thus obtained in the memory unit 10b enables the steam flow rate calculation device 10 to function properly. The applicant's investigation has confirmed that the load on the retort sterilizer 30 (the amount of food or the like placed in the retort pot 30a) has almost no effect on the correction coefficient K determined using the flow meter-equipped system 1x.

[0052] 4. Summary As described above, the steam flow rate calculation device 10 of this embodiment is a device that sequentially calculates the mass flow rate of steam in a steam supply system X that supplies steam from a steam supply source 12 to a high-temperature side of a heat exchanger 16 (one form of supply target that involves steam condensation) via a proportional valve 15, and is equipped with a monitoring unit 10a that monitors a first pressure value P1 that is the pressure value of the steam on the upstream side of the proportional valve 15, a second pressure value P2 that is the pressure value of the steam on the downstream side of the proportional valve 15, and the Cv value of the proportional valve 15, and a memory unit 10b that stores each correction coefficient K determined for each of a plurality of different Cv values ​​of the proportional valve 15, and calculates the mass flow rate based on the first equation described above.

[0053] Therefore, the steam flow rate calculation device 10 can calculate the steam flow rate for the steam supply system X that supplies steam to a supply target that involves steam condensation via the proportional valve 15. This makes it possible to monitor the steam flow rate in the steam supply line 11 without the need to install a steam flow meter.

[0054] In addition, the flow meter-equipped system 1x includes a corresponding proportional valve (proportional valve 15 shown in FIG. 5) corresponding to the proportional valve 15 of the steam supply system X, a corresponding supply target (the high-temperature side of the heat exchanger 16 shown in FIG. 5) corresponding to the high-temperature side of the heat exchanger 16 of the steam supply system X, and a steam flow meter 14 that measures the mass flow rate of steam, and is configured to perform a supply operation of supplying steam from the steam supply source 12 to the corresponding supply target via the steam flow meter 14 and the corresponding proportional valve in that order.

[0055] The data acquisition method for obtaining data for each correction coefficient K used in the steam flow rate calculation device 10 using the flow meter-equipped system 1x is a method in which the Cv value of the corresponding proportional valve in the flow meter-equipped system 1x is sequentially set to a plurality of different values, and for each setting, the value of K calculated based on Equation 1, with the measurement value of the steam flow meter 14 when a supply operation is performed set as Q, is set as the correction coefficient K corresponding to the Cv value at that time. According to this data acquisition method, the flow meter-equipped system 1x is used to simulate the operation of supplying steam from the steam supply source 12 in the steam supply system 1 to a supply target via the proportional valve 15, and data for each correction coefficient K can be acquired.

[0056] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the claims, not by the description of the above-described embodiments, and should be understood to include all modifications that fall within the meaning and scope of the claims.

[0057] <Contribution to the United Nations-led Sustainable Development Goals (SDGs)> The steam flow rate calculation device according to the present disclosure is applied to monitoring steam flow rates, enabling accurate understanding of energy consumption and loss. Understanding energy consumption and loss can lead to energy savings through the renovation and reconstruction of heat utilization equipment. This will promote the reduction of carbon dioxide emissions and contribute to the realization of Goal 13 of the Sustainable Development Goals (SDGs), "Take urgent action to combat climate change." [Industrial Applicability]

[0058] The present invention can be used in heating systems that use steam for heating. [Explanation of symbols]

[0059] 1. Heating system 1x system with flow meter 10 Steam flow rate calculation device 10a Monitoring section 10b Storage section 11 Steam supply line 12 Steam source 13 Pressure reducing valve 14 Steam flow meter 15 Proportional valve 16 Heat exchanger 17 Circulation Route 18a First pressure sensor 18b Second pressure sensor 19 Temperature Sensor 20 Control device 30 Retort Sterilizer 30a Retort pot X Steam Supply System

Claims

1. 1. A steam flow rate calculation device in a steam supply system that supplies steam from a steam supply source via a proportional valve to a supply target that involves steam condensation, the device sequentially calculating a mass flow rate of the steam, a monitoring unit that monitors a first pressure value that is a pressure value of the steam on an upstream side of the proportional valve, a second pressure value that is a pressure value of the steam on a downstream side of the proportional valve, and a Cv value of the proportional valve; a memory unit that stores correction coefficients determined for a plurality of different Cv values ​​in the proportional valve, A steam flow rate calculation device that calculates the mass flow rate (referred to as Q) based on the following first equation. Q=K×Cv×{dP(P1+P2)}^0.5...Equation 1 Here, P1 is the first pressure value at that time, P2 is the second pressure value at that time, dP is the difference between P1 and P2, Cv is the Cv value of the proportional valve at that time, and K is the correction coefficient corresponding to Cv.

2. The monitoring unit 2. The steam flow rate calculation device according to claim 1, wherein detection information of a pressure sensor disposed between the steam supply source and the proportional valve is acquired as information on the first pressure value, and detection information of a pressure sensor disposed between the proportional valve and the supply target is acquired as information on the second pressure value.

3. The steam flow rate calculation device according to claim 1 , wherein the supply target is a high temperature side of a heat exchanger.

4. A heating system comprising the steam flow rate calculation device according to claim 3 and the steam supply system, and configured to supply a heat medium that has exchanged heat with the steam in the heat exchanger to a heating target, A heating system that controls the opening degree of the proportional valve based on a temperature detected in the object to be heated.

5. The heating system according to claim 4, wherein the object to be heated is a retort oven.

6. A data acquisition method for obtaining data of the correction coefficients used in the steam flow rate calculation device according to any one of claims 1 to 3, using a system equipped with a flow meter, comprising: the flow meter-equipped system includes a corresponding proportional valve corresponding to the proportional valve, a corresponding supply target corresponding to the supply target, and a steam flow meter that measures a mass flow rate of steam, and is configured to perform a supply operation of supplying steam from a steam supply source to the corresponding supply target via the steam flow meter and the corresponding proportional valve in this order; In the flow meter-equipped system, the Cv value of the corresponding proportional valve is sequentially set to a plurality of different values, A data acquisition method in which, for each setting, the measured value of the steam flow meter when the supply operation is performed is set to Q, and the value of K calculated based on the first equation is set to the correction coefficient corresponding to the Cv value at that time.

Images