JP2007248154A - Flow measuring device - Google Patents

Abstract

An object of the present invention is to eliminate a temperature correction error caused by a difference between a measured temperature measured by a temperature sensor and a fluid temperature when a fluid temperature change occurs.
A shipping control device includes a correction means for performing a temperature correction calculation according to a temperature estimated from a measured temperature value of a flow rate of a shipped oil liquid, and a temperature measured by a temperature sensor. A temperature change measuring unit 52 that measures the magnitude of the change, and a temperature change storage unit 54 that stores a correspondence relationship between the temperature change of the fluid and the temperature of the fluid with respect to the temperature change. Further, the correcting unit 50 calculates the flow rate value measured by the flow meter 32 based on the temperature change measured by the temperature change measuring unit 52 and the temperature of the fluid corresponding to the temperature change stored in the temperature change storage unit 54. to correct.
[Selection] Figure 1

Description

  The present invention relates to a flow rate measuring device, and more particularly to a flow rate measuring device configured to perform temperature correction according to a temperature change by a temperature measuring device that measures the temperature of a fluid to be measured.

  The oil solution refined at the refinery is measured for example in the process of being loaded into a tanker, and the temperature is measured to correct the measured flow rate value to the flow rate value at the reference temperature (15 ° C.). As a result, an accurate flow rate can be registered regardless of the temperature change of the oil liquid, and whether or not the oil liquid has leaked is also confirmed.

  In addition, when oil is loaded into a tanker at a refinery, the temperature of the oil flowing through the pipeline is measured, and the integrated value of the value obtained by correcting the volume flow measured by the flow meter is the reference temperature (15 ° C). ), And when unloading from the tanker to the storage tank of the oil tank station, the integrated flow rate corrected for temperature is used as the unloading volume corresponding to the reference temperature (15 ° C). (Registered in the computer of the management center that collectively manages the oil liquid in the oil tank station) (see, for example, Patent Document 1).

In addition, the temperature of the oil liquid flowing in the pipeline line is measured by a temperature sensor using a resistance temperature detector. This type of temperature sensor is configured such that the resistance thermometer is inserted into a protective tube made of a metal pipe so that the rod-shaped resistance thermometer does not directly receive the flow velocity or pressure of the fluid to be measured.
Japanese Patent Laid-Open No. 2002-362697

  However, in the conventional flow rate measuring device, the temperature sensor is configured by the protection tube so that the resistance temperature detector is not directly subjected to the flow velocity or pressure of the fluid to be measured, and the fluid to be measured flows into the protection tube. Because temperature changes are difficult to detect with a resistance temperature detector, if the temperature of the fluid to be measured changes, the resistance temperature detector will keep the temperature of the fluid to be measured until the heat of the fluid is transferred to the inside of the protective tube. Since the change can be accurately detected, the temperature correction of the flow rate value is performed, and there is a problem that an error occurs in the temperature correction value.

  Therefore, an object of the present invention is to provide a flow rate measuring apparatus that solves the above-described problems.

  In order to solve the above problems, the present invention has the following means.

  The invention according to claim 1 is a flow meter for measuring the flow rate of the fluid to be measured flowing in the pipe, and a temperature measuring device that is provided so as to protrude into the flow path through which the fluid to be measured flows and measures the temperature of the fluid to be measured And a correction means for correcting the flow rate measured by the flow meter based on the temperature detected by the temperature measuring device, wherein the temperature measured by the temperature measuring device is changed in magnitude to a temperature. Temperature change calculation means for measuring, and temperature change storage means for storing a correspondence between the temperature change of the fluid to be measured and the temperature of the fluid with respect to the temperature change, and the correction means includes the temperature change calculation means. The flow rate measured by the flowmeter is corrected based on the temperature change calculated by the above and the temperature of the fluid to be measured corresponding to the temperature change stored in the temperature change storage means.

  According to a second aspect of the present invention, the correcting means corresponds to the temperature measured by the temperature measuring instrument, the temperature change calculated by the temperature change calculating means, and the temperature change stored in the temperature change storage means. The flow rate measured by the flowmeter is corrected based on the temperature of the fluid to be measured.

  According to the present invention, in order to correct the flow rate measured by the flow meter based on the temperature change calculated by the temperature change calculation means and the temperature of the fluid to be measured corresponding to the temperature change stored in the temperature change storage means. When the temperature of the fluid to be measured has changed, the temperature of the fluid to be measured can be estimated by estimating the temperature of the fluid to be measured corresponding to the temperature change stored in the temperature change storage means. More accurate temperature correction becomes possible.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a system diagram showing a shipping system to which an embodiment of a flow rate measuring apparatus according to the present invention is applied. As shown in FIG. 1, the oil tank station shipping system includes a shipping control device 14 of a shipping device 10 installed at a shipping site, a hatch setting device 12 installed in an office remote from the shipping site, and shipping management. The host computer 13 is a computer. As will be described later, the shipping control device 14 includes a correction means 50 that performs a temperature correction calculation according to the temperature estimated from the temperature measurement value of the flow rate measurement value of the shipped oil and the temperature measured by the temperature sensor 40. A temperature change measuring unit 52 that measures the magnitude of the change, and a temperature change storage unit 54 that stores a correspondence relationship between the temperature change of the fluid and the temperature of the fluid with respect to the temperature change.

  Further, the correction means 50 is based on the temperature change measured by the temperature change measurement means 52 and the temperature of the fluid corresponding to the temperature change stored in the temperature change storage means 54, for example, a roots having an eyebrows-type rotor. The flow rate value measured by a volumetric flow meter (flow meter) 32 such as a positive displacement flow meter such as a flow meter or a turbine flow meter having an impeller is corrected.

  The host computer 13 in the oil tank station is connected to a computer 25 installed in the reservation center via a public line 23 so as to be communicable. When there is an order (oil type and quantity) from a customer such as a gas station, the computer 25 stores these orders (oil type and quantity) as reservation information and manages the shipping reservation status of the oil tank, In accordance with an order from the customer, a delivery plan for which oil tanks to deliver these oil solutions is created. Therefore, the data of the delivery destination of each tank truck 15 and the ordered oil type and quantity is transferred to the host computer 1 from the computer 25 of the reservation center.

  The host computer 13 stores the order (oil type and quantity) from the customer in the storage device 13 a and transfers reservation data to the shipping control device 14 and the hatch setting device 12 of the shipping device 10. The hatch setting device 12 includes a card reader / writer 18, a display body 19, a keyboard 20, a printer 21, a CPU 22, and the like.

  The shipping control device 14 of the shipping device 10 is provided for each shipping stage 17 and controls each device of the shipping stage 17, and a car number card 37 distributed to each tank truck 15 is received by the card reader 24. When read, the reservation data of the corresponding vehicle number is transferred from the host computer 13, and shipping control is performed so that the oil type and quantity included in the reservation data are loaded into the tank truck 15.

  The tank truck 15 is divided into a plurality of hatches in the tank 16, and the capacities of the hatches are different, for example, 1 kiloliter, 2 kiloliters, and 4 kiloliters. When the tank truck 15 arrives at the shipping stage 17, the oil type set by the hatch setting device 12 is loaded into each hatch of the tank 16.

  The shipping device 10 includes a shipping control device 14, a card reader 24, a remote switch box 26 having a hatch card reader, a ground device 27, a loading setting device 28 for setting a quantity to be loaded for each shipping point by an operator, and the like.

  The loading setter 28 is provided with a loading amount setting switch 28a for setting the loading amount, a start switch 28b for starting shipment, and a stop switch 28c for stopping shipment. Further, the remote switch box 26 and the loading setting device 28 of this embodiment are integrated, and these are attached to the loading arm 35.

  A loading arm 35 is communicated with the leading end of the feed pipe 29. In the shipping stage 17, only one loading arm 35 is shown, but in practice, a plurality of loading arms 35 are provided for each oil type.

  The feed pipe 29 is provided with a pump 30, a strainer 31, a flow meter 32, a constant flow valve 33, and a metering valve 34. In addition, the feed pipe 29 is provided with a temperature sensor (temperature measuring device) 40 for measuring the temperature of the oil liquid. The temperature sensor 40 uses, for example, a resistance temperature detector that utilizes the temperature dependence of the electrical resistance of metal, and outputs a detection signal corresponding to the temperature of the oil flowing through the supply pipe 29 to the shipment control device 14. Output to.

  FIG. 2 is a vertical cross-sectional view showing a mounting state of the temperature sensor 40. As shown in FIG. 2, the temperature sensor 40 has the temperature measuring resistor 42 inserted into a protective tube 44 made of a metal pipe so that the rod-shaped temperature measuring resistor 42 does not directly receive the flow rate or pressure of the oil liquid. It is configured to be. Further, the protective tube 44 is filled with a liquid, and the temperature change of the liquid is measured by the resistance temperature detector 42. Therefore, the temperature sensor 40 is configured so that the resistance temperature detector 42 is not directly subjected to the flow velocity or pressure of the oil liquid by the protective tube 44. Therefore, when the temperature change occurs, the actual fluid temperature change is not detected. The temperature change is detected after a certain delay from the occurrence.

  FIG. 3 is a diagram schematically showing a database storing the relationship between the temperature change rate A and the temperature difference ΔT. As shown in FIG. 3, in the temperature change rate-temperature difference database 60, the temperature difference ΔT (the difference between the fluid temperature and the measured temperature) with respect to the temperature change rate A of the oil liquid is obtained in advance by experiments. Experimental data is registered. The database 60 is stored in the temperature change storage means 54 described above.

  Further, since the relationship between the temperature change rate and the temperature difference is not necessarily a proportional relationship, the reliability of the value based on the experimental data is high. Furthermore, since the temperature sensor 40 has a configuration in which a resistance temperature detector is inserted into the protective tube, it is conceivable that the value of the temperature difference ΔT varies depending on the velocity of the fluid flowing into the protective tube. For this reason, since the temperature difference with respect to the rate of temperature change varies as the viscosity of the fluid to be measured (oil liquid) changes with temperature, it is desirable to prepare a temperature change rate-temperature difference database 60 for each oil type.

  FIG. 4 is a flowchart for explaining the temperature correction processing executed by the shipment control device 14. The shipping control device 14 repeatedly executes the temperature correction process shown in FIG. 3 at predetermined time intervals. As shown in FIG. 4, the shipment control device 14 reads the temperature B measured by the temperature sensor 40 in S <b> 11. Then, it progresses to S12 and the actual flow volume value measured by the flowmeter 32 is read.

  In next S13, the temperature change rate A is calculated from the temperature difference between the temperature measurement value of the previous process and the temperature measurement value of the current process and the measurement time difference. Subsequently, the process proceeds to S14, and the temperature difference ΔT corresponding to the calculated temperature change rate A is read from the database 60.

  In the next S15, the current fluid temperature T is calculated (estimated) by adding the temperature difference ΔT corresponding to the temperature change rate A to the temperature B measured by the temperature sensor 40. In S16, a temperature correction calculation corresponding to the reference temperature (15 ° C.) is performed based on the current fluid temperature T.

Here, the calculation formula of the temperature correction calculation performed in S16 will be described. The calculation formula of the volume conversion coefficient (VCF) of the reference temperature (15 ° C) is defined in JIS standard (basic formula for density conversion and capacity conversion with respect to temperature: JIS 2249-1987 calculation formula) and is defined as follows: Has been.
VCF = (V ₁₅ / Vt) (ρt / ρ ₁₅ )
_{= Exp [-α T Δt (1.0} + 0.8α T Δt)] ... (1)
α _T = K ₀ −Kρ ₁₅ / (ρ ₁₅ ) ²
= {K ₀ / (ρ ₁₅ ) ² } + {K ₁ / ρ ₁₅ } (2)
α _T = A + B / (ρ ₁₅ ) ² (3)
However, Formula (3) is applied only to the fuel oil having a density (15 ° C.) of 0.7705 to 0.7875 g / cm ² .

Further, the arithmetic formula _{(1) ~ (3),} V 15 capacity at 15 ° C is ^(m 3), volume ^(m 3) in Vt is arbitrary temperature (t ° C), ρt is the density (t ° C ) (Kg / m ³ ), ρ ₁₅ is the density (15 ° C.) (kg / m ³ ), α _T is the coefficient of thermal expansion (° C ⁻¹ ) at 15 ° C., Δt is the temperature difference [Δt = t− 15] (° C), K ₀ , K ₁ , A, and B are constants determined to be different values depending on the oil type. Δt is the difference between the fluid temperature T and the reference temperature.

  In this embodiment, the shipment control device 14 samples the temperature of the oil liquid at regular intervals, calculates a volume conversion coefficient (VCF) of the detected temperature, and stores it in the database 60. Then, the shipping control device 14 reads the latest volume conversion coefficient (VCF) updated every predetermined time from the database 60 at the time when the loading of the oil liquid into the tank truck 15 is completed, and the calculation formulas (1) to (1)- Based on (3), the temperature correction calculation process of the loading amount can be executed to calculate the loading amount at the reference temperature (15 ° C.).

  Then, the process proceeds to S17, and the flow rate value corrected so as to correspond to the reference temperature (15 ° C.) is output.

  Thus, when the fluid temperature changes, the temperature difference close to the actual fluid temperature can be estimated by adding or subtracting the temperature difference ΔT corresponding to the temperature change rate A to the measured temperature value, Regardless of the measurement delay of the temperature sensor 40, even when the fluid temperature changes, temperature correction according to the fluid temperature change can be performed with higher accuracy, and the reliability of the flow rate measurement value can be improved.

  In the above embodiment, the case where the flow rate measurement value of the oil liquid loaded on the tank truck 15 is corrected to the flow rate value corresponding to the reference temperature has been described as an example. However, the present invention is not limited to this, and other oil liquids are supplied. Of course, the present invention can also be applied to the case where the flow rate measurement value is temperature-corrected during the process.

  In the above embodiment, the relationship between the temperature change rate and the temperature difference is obtained by experiment in advance. However, since the difference between the actual fluid temperature corresponding to the temperature change and the measured temperature is known, the temperature change rate Of course, a value other than (for example, a temperature difference when sampling is performed) may be used.

  In the above embodiment, the case where the fluid temperature is measured by the temperature sensor using the resistance temperature detector has been described. However, it goes without saying that the present invention can be applied to the case where the fluid temperature is measured by other temperature sensors. Yes.

FIG. 4 is a flowchart for explaining the temperature correction processing executed by the shipment control device 14. It is a longitudinal cross-sectional view which shows the attachment state of the temperature sensor 40. FIG. It is the figure which showed typically the database which memorize | stored the relationship between the temperature change rate A and temperature difference (DELTA) T. 5 is a flowchart for explaining a temperature correction process executed by a shipment control device 14;

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ship apparatus 12 Hatch setting device 14 Ship control apparatus 15 Tank truck 29 Feeding piping 32 Volume flow meter (flow meter)
40 Temperature sensor 42 Resistance temperature detector 44 Protection tube 50 Correction means 52 Temperature change measurement means 54 Temperature change storage means 60 Database

Claims (2)

A flow meter for measuring the flow rate of the fluid to be measured flowing in the pipe;
A temperature measuring device that protrudes into the flow path through which the measured fluid flows and measures the temperature of the measured fluid;
Correction means for correcting the flow rate measured by the flowmeter based on the temperature detected by the temperature measuring device;
In a flow measuring device having
Temperature change calculating means for calculating the magnitude of the temperature change to the temperature measured by the temperature measuring instrument;
Temperature change storage means for storing a correspondence relationship between the temperature change of the fluid to be measured and the temperature of the fluid with respect to the temperature change;
Provided,
The correction means corrects the flow rate measured by the flowmeter based on the temperature change calculated by the temperature change calculation means and the temperature of the fluid to be measured corresponding to the temperature change stored in the temperature change storage means. A flow rate measuring device characterized by:   The correction means is based on the temperature measured by the temperature measuring instrument, the temperature change calculated by the temperature change calculation means, and the temperature of the fluid to be measured corresponding to the temperature change stored in the temperature change storage means. A flow rate measuring apparatus for correcting a flow rate measured by the flow meter.

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