Testing device for determining smoke point and method for determining smoke point

Abstract

A test apparatus and method for determining the smoke point of hydrocarbons, the apparatus including: a device for determining smoke point conforming to the specifications of ASTM D1322-19 standard or an equivalent standard; an imaging device for taking a series of digital images of a flame; an ambient relative humidity sensor for measuring relative humidity; an ambient temperature sensor for measuring temperature; and a computer system connected to the imaging device, the humidity sensor, and the temperature sensor, the computer system being programmed to: analyze the digital images from the imaging device to measure flame height; calculate absolute humidity using the relative humidity and temperature measured by the temperature and humidity sensors; correct the measured flame height as a function of the difference between the calculated absolute humidity and a normalized absolute humidity; and preferably correct the measured flame height as a function of the difference between the pressure during the flame height measurement and the normalized pressure.

Description

[Technical Field]

[0001] The present invention provides a test apparatus and method for determining smoke point by correcting the measured smoke point to take into account ambient humidity, temperature, and optionally pressure, and a method for determining smoke point. [Background technology]

[0002] The smoke point of hydrocarbons is a property routinely measured in oil refinery laboratories for kerosene, aviation fuel, lamp oil, etc. This property is an important parameter that is directly related to the hydrocarbon composition of the specific fuel being tested. In fact, the higher the carbon (C) to hydrogen (H) ratio (C:H), i.e., the lower the aromatics content, the higher the smoke point and the better the combustion behavior of the fuel. In other words, the smoke point is quantitatively linked to the possibility of radiative heat transfer, and since this heat transfer has a strong influence on the temperature of metal parts, the smoke point is a predictor of the lifespan of said metal parts.

[0003] However, one drawback of using smoke point as a predictive indicator is its difficulty in measurement. Typically, standardized analytical methods are used to enable detection (e.g., ASTM D1322-19, Standard Test Method for Smoke Point of Kerosene and Aviation Turbine Fuel, ASTM International, West Conshohocken, PA, 2019, www.astm.org, and equivalents such as ISO 3014, IP 57, and NF M 07-028, which are incorporated herein by reference) by measuring the maximum flame height of the tested hydrocarbon sample without measuring smoke formation. This measurement is typically expressed in millimeters ("mm") and accurate to within tenths of a millimeter. There is little (or no) difference between the ASTM D1322-19 standard and standards such as ISO, IP, NF, GOST, and JIS.

[0004] In these measurements, hydrocarbon test samples are burned in a wick lamp (also described in ASTM D1322-19) with a candle and wick. This test requires the setting of a wick height, and the position of the candle is varied to gradually change the flame height and appearance through the following flame appearance sequence: The flame height and appearance gradually change from a relatively elongated, protruding tip with a concave tip and light smoke emanating from the top of the flame to a short flame height and a completely rounded top. Between these two flame states, the test operator must also distinguish between two intermediate flame shapes: an elongated, concave-topped intermediate flame, and a smokeless intermediate flame, where the tip of the flame has just disappeared and the flame is slightly rounded (slightly dull). When the flame reaches this final appearance, the flame height is recorded by the operator or an automated measuring device (using a digital image) on a scale measured in millimeters inside the lamp and on the back. The flame height at the smoke point shall be observed three separate times, repeating the sequence of flame appearance, for a total of three consecutive measurements. If these measurements vary by more than 1.0 mm, repeat the test with a new sample and a different wick. The final smoke point value retained for the sample under analysis is the average of the three consecutive measurements, calculated to the nearest 0.1 mm.

[0005] The manual smoke point measurement method specified in the ASTM D1322-19 standard, like all analytical methods of this type, has limitations in terms of accuracy. For example, it is often difficult for the test operator to determine whether the flame appearance is correct and whether the moment at which the flame height should be measured on the scale is correct. To ensure quality results, certain procedures and precautions should be taken when measuring flame height, but the implementation of these procedures and precautions is entirely up to the test operator. Thus, the repeatability and reproducibility of the standardized test are limited to 2 mm and 3 mm, respectively.

[0006] U.S. Patent No. 7,829,343 to Reminiac et al. discloses an automated method and apparatus for determining the smoke point of hydrocarbons in accordance with ASTM D1322 or its equivalent, as an improvement over the manual method. Reminiac et al.'s U.S. Patent No. 7,829,343 discloses a method and apparatus for determining the smoke point of hydrocarbons, which, among the different steps defined in ASTM D1322 or its equivalent, includes identifying a specific aspect of the flame among the different aspects of the flame depending on the position of the burner within the lamp, and reading the height of the flame in millimeters. This method is characterized by the fact that a series of digital images of the flame are taken and recorded using a digital camera or the like at sufficiently short intervals, and by analyzing these digital images, a sudden change in the flame shape can be detected, and the flame height at the moment of this sudden change is measured. This height is considered the smoke point of the tested hydrocarbon. A commercial device employing this patented system is the Automated Smoke Point-SP10 from AD Systems. The AD Systems Automated Smoke Point-SP10 uses a system that adjusts the flame size relative to a video camera observing the flame. Once the flame has achieved the configuration described in the test method, the SP10 stores and reports the flame height. The SP10 is specified as an evaluation method in ASTM D1322. Section 6.2.2 of ASTM D1322-19 states, "Because the resolution of digital cameras is vastly superior to that of the human eye, smoke point measurements shall be made by automated equipment, when available. In the event of a dispute between manual and automated results, the automatic method shall be the evaluator."

[0007] However, smoke point measurements obtained with current systems and methods can be adversely affected by ambient pressure conditions experienced or encountered at the test site, and therefore current systems are calibrated to take barometric pressure into account.

[0008] For manual instruments, Section 10 of ASTM D1322-19 requires the operator to verify the instrument's calibration before its first use of the day in accordance with Section 10.1.3 of ASTM D1322-19 or, if necessary, calibrate it in accordance with Section 10.1.1 of ASTM D1322-19. Recalibration is required if there are any changes to the instrument or operator, or if the barometric pressure reading changes by more than 0.7 kPa. Calibrate the instrument by testing two of the reference fuel blends specified in Section 7.4 of ASTM D1322-19 using the procedure specified in Section 11 of ASTM D1322-19, bracketing the smoke points of the samples, if possible. If this is not possible, use two test blends with smoke points closest to that of the sample. The instrument's correction factor, f (sometimes called the ramp factor), is determined from the following equation:

[0009]

number

[0010] In the method using an automatic device, according to Section 10 of ASTM D1322-19, the automatic device can automatically calculate the correction factor f according to equation (1) using stored reference data. The device shall have a calibration database for storing values ​​of reference fuel blends specified in Table 1 of ASTM D1322-19.

[0011] [Table 1]

[0012] Each calibration test performed using a reference fuel blend shall be stored in this database, along with the barometric pressure observed at the moment the calibration was performed. Section 10.2.1 of ASTM D1322-19 discloses that the automated equipment must have the capability to automatically select the reference fuel blend value specified in Table 1 in the calibration database using the procedure specified in Section 11 and the calculation specified in Section 12, and automatically calculate the correction factor f according to Equation (1) by bracketing the smoke point of the sample, if possible. If this is not possible, the results of the two test blends with smoke points closest to that of the sample shall be used. A digital camera and associated software observe the flame instead of the operator's eyes. This eliminates the need for automated equipment recalibration when the operator changes.

[0013] Section 12 of ASTM D1322-19 discloses calculating the smoke point to the nearest 0.1 mm via the following formula (2):

[0014]

number

[0015] In manual systems, this calculation is performed by the operator, but in automatic systems, the smoke point is calculated automatically.

[0016] However, for automated instruments, Section 10.2.2 of ASTM D1322-19 teaches recording the barometric pressure and verifying in a calibration database that the instrument was calibrated at the recorded pressure ±0.7 kPa. If calibration values ​​for the seven blends specified in Table 1 at the observed pressure ±0.7 kPa do not exist, Section 10.2.2 of ASTM D1322-19 teaches calibrating the instrument according to Section 10.2.3. If calibration values ​​exist for the seven blends specified in Table 1, i.e., if the instrument has already been calibrated at the observed pressure, ASTM D1322-19 teaches verifying the instrument according to Section 10.2.4. Automatic instruments store smoke points obtained using reference fuels at different barometric pressures. Thus, if the instrument has already been calibrated at the observed pressure, a change in barometric pressure greater than 0.7 kPa does not require recalibration. Depending on the barometric pressure entered at the start of the test, the instrument automatically uses the correct stored value obtained for the fuel blend. If the correct value is not already stored, the device will prompt the operator to perform a calibration at the observed pressure again using the procedure specified in Section 11 in accordance with Section 10.2.3 of ASTM D1322-19, which discloses calibrating the device by testing seven reference fuel blends as specified in Section 7.4 of ASTM D1322-19.

[0017] Thus, with the conventional method, if the pressure fluctuates by more than 0.7 kPa (manual method ASTM D1322-19, section 10.1), or if the calibration database for an automated instrument does not contain a calibration value within 0.7 kPa of the atmospheric pressure at the time of the test (ASTM D1322-19, section 10.2.2), a new calibration of the instrument is required.

[0018] If the (automated) testing equipment records calibration values ​​at different atmospheric pressures but does not have saved (stored) calibration values ​​performed at pressures close to the current pressure, the constraint remains that the equipment must be calibrated with seven reference fuel blends before performing a smoke point measurement on the particular fuel sample being tested.

[0019] For example, because the smoke point values ​​of the fuel samples to be tested are not known in advance, it is (theoretically) necessary to have values ​​(i.e., calibration values) for all seven reference fuel blends at the same atmospheric pressure at which the test procedure measurements will be performed. This is challenging because it is difficult to have all the calibration values ​​in 0.7 kPa increments, so it is often necessary to calibrate at the appropriate pressure before running the test method. For this reason, many test operators simplify (i.e., "cheat") the calibration process by entering a pressure value that already has a calibration value.

[0020] It would be desirable to provide an apparatus and method for improving the automatic calibration of smoke point measurements. (overview)

[0021] ASTM D1322-19 does not describe corrections as a function of humidity or temperature. ASTM D1322-19 requires that automatic instruments have a calibration database for storing reference fuel blends, as specified in Table 1, to correct for air pressure during measurement. The calibration process in ASTM D1322-19 is primarily performed to correct for variations in atmospheric pressure. This includes correcting for parameters specific to each instrument, which do not change over time. For manual and current automatic instruments, the operator measures the current air pressure with a separate barometer and manually enters the measurement into the instrument. Measurement corrections in ASTM D1322-19 are based on a comparison with the deviation measured with the reference product (reference fuel blend, Mixtures 1 through 7) under the same conditions as the test being performed. If the test is performed under the same conditions, the corrections are accurate. However, in practice, this is not usually the case. This is because the calibration values ​​are stored and therefore based on tests performed days, months, or even years before the current test, and only the atmospheric pressure is recorded during the calibration test, not other variables that may affect the results, such as humidity, temperature, or other parameters.

[0022] Calibration is used to correct for bias in measurements by comparing them to a reference pressure value of 101.3 kPa. However, in smoke point measurements, a source of bias that can affect the final measurement result is due to the humidity of the atmosphere in which the calibration is performed. Conventional devices and methods cannot reduce or eliminate bias or error due to humidity because they do not measure or record humidity conditions. Thus, even if a particular test is known to be performed on kerosene at the same pressure during or at the same time as calibration, humidity conditions may be different (because humidity is not measured or recorded). This introduces smoke point measurement error and alters the repeatability of the test.

[0023] Air humidity and ambient temperature can have a significant effect on the results when measuring smoke point according to the test method. For example, in humid regions (e.g., Southeast Asia during the monsoon season), it is difficult to carry out the test method with known test equipment, as the measured values ​​during calibration are outside the accredited range of the ASTM D1322-19 standard.

[0024] The present invention automatically corrects for the effects of atmospheric conditions on smoke point measurements according to the ASTM D1322-19 standard or equivalents, such as ISO 3014, IP 57, and NF M 07-028. There is no (or very little) difference between the ASTM D1322-19 standard and equivalent standards, such as ISO, IP, NF, GOST, and JIS. The present apparatus and method conform to these equivalent standards. Therefore, an apparatus for determining a smoke point according to the specifications of the ASTM D1322-19 standard is also an apparatus for determining a smoke point according to the specifications of an equivalent standard. Therefore, a method for determining a smoke point according to the specifications of the ASTM D1322-19 standard is also a method for determining a smoke point according to the specifications of an equivalent standard.

[0025] The present invention automatically corrects for the effects of humidity on smoke point measurements.Preferably, the present invention automatically corrects for the effects of humidity and pressure on smoke point measurements.

[0026] The present invention provides an apparatus and method for automatically correcting smoke point measurements (flame heights typically measured in millimeters) according to atmospheric conditions. For example, the apparatus and method automatically correct for ambient (atmospheric) air temperature and humidity. Specifically, the present invention accounts for humidity coefficients, eliminating induced errors due to humidity fluctuations. The amount of moisture in air disrupts kerosene combustion and thus perturbs smoke point values. The density of water vapor in air is called absolute humidity and is measured in units of kg / m3. Humidity sensors display relative humidity (RH) in %RH. Calculating absolute humidity from relative humidity is well documented in the art. Calculating absolute humidity from relative humidity requires measuring air temperature and atmospheric pressure simultaneously with relative humidity. Therefore, the apparatus of the present invention is equipped with sensors to measure relative humidity, air temperature, and typically atmospheric pressure. It should be noted, however, that atmospheric pressure has little effect on this absolute humidity calculation (less than 0.1% for a 250 hPa variation).

[0027] The present invention corrects for variations in atmospheric conditions and other factors, allowing all influences to be corrected. The present invention automatically corrects the measured smoke point value for humidity and temperature. The present invention corrects the smoke point measurement (flame height in mm) as a function of the difference between the calculated absolute humidity and the normalized absolute humidity. The present invention preferably corrects the smoke point measurement for a temperature of 7 gr / m 3 We choose to normalize with absolute humidity because that is the usual value for reference mixtures, although this can be another value, typically between 0 and 40 gr / m 3101.3 kPa (also known as 1013 hPa (hectopascals) or 1 atmosphere). The present invention preferably chooses to normalize smoke point measurements to 1013 hPa, since that is the typical value for reference mixtures. However, this can be another value, typically a normalized value for atmospheric pressure on Earth, between 800 and 1100 hPa.

[0028] The present invention also integrates an air humidity sensor and an ambient temperature sensor into the device of the present invention, and uses the measurements to correct the flame height measurement. Corrections can be applied during flame height measurement or to the smoke point results in real time. The device of the present invention may also be integrated with an atmospheric pressure sensor. However, the atmospheric pressure can also be read by an external barometer and entered into the device. The integration of a pressure sensor primarily avoids operator error when reading the barometer and operator typing errors when entering data. The integration of a pressure sensor also ensures better traceability of the test.

[0029] Preferably, the present invention not only corrects the measured smoke point value for humidity and temperature, but also for atmospheric pressure, eliminating the need to perform (or previously perform and store) a calibration every time the pressure varies by more than ±0.7 kPa from the pressure during calibration.

[0030] The pressure correction of the present invention differs from the correction currently applied in the ASTM D1322-19 standard, which implicitly links the calibration process using a reference mix to atmospheric pressure by indicating that a pressure change of more than 0.7 kPa should trigger a recalibration.

[0031] However, as shown above, smoke point results are affected by a variety of factors, including atmospheric pressure, humidity, camera or lens malfunctions, and adjustment tolerances, as well as errors related to the camera itself used to measure smoke point.

[0032] The ASTM D1322-19 standard uses a ramp factor "f" to account for errors related to the camera used to measure smoke point, such as camera or lens malfunction or adjustment tolerances, and accounts for pressure changes by requiring a recalibration when the pressure changes by more than 0.7 kPa. However, this needs to be improved to account for other atmospheric factors. Also needed is a better way to accommodate pressure fluctuations so that a recalibration is not required when there is a pressure change of more than 0.7 kPa between the time of initial calibration and the time the test sample is measured.

[0033] The ASTM D1322-19 standard corrects smoke point results by comparing the results with those obtained using two reference mixtures (which bracket the result) and applying the average of the measurement deviations obtained with respect to the reference values ​​of these mixtures as the correction.

[0034] This is accurate if the measurement of the mixture (called calibration) and the measurement of the kerosene being tested are carried out under the same conditions, i.e., the same pressure and humidity. However, the ASTM D1322-19 standard does not take humidity into account and requires calibration to be repeated only to maintain near atmospheric pressure between tests and calibrations, which can introduce error into the measurement of kerosene's smoke point.

[0035] For example, pressure 980hPa, humidity 9gr / m 3 Calibration was performed at the same pressure of 980 hPa and humidity of 21 gr / m 3 When the smoke point test is performed at 980hPa and the standard method is applied, the result is 9gr / m 3 This value X corresponds to the humidity difference of 12 gr / m between the calibration and the smoke point measurement. 3 is incorrect because it does not take into account

[0036] The inventors have found that humidity has a very strong effect on the results, causing major problems with the reproducibility of the test. To solve this problem, the present invention measures humidity during calibration and testing or simultaneously with calibration and testing, and calculates a humidity correction factor f h The inventors thus investigated the effect of humidity (humidity alone, while holding constant other possible influencing variables) on smoke point results. From this study, the inventors developed a correction factor f to correct the measurement results as a function of absolute humidity. h The absolute humidity correction formula was derived using the absolute humidity correction coefficient f h The humidity correction formula using can be empirically determined from the data. Potentially, the humidity correction factor f h This humidity correction formula is not taught or suggested in the conventional ASTM D1322-19 standard process.

[0037] Thus, a first aspect of the present invention is to determine absolute humidity by calculating absolute humidity using measurements of relative humidity, ambient temperature, and ambient atmospheric pressure. Calculating absolute humidity is well known to those skilled in the art. However, the inventors point out that atmospheric pressure plays a negligible role in determining absolute humidity. While not preferred, one approach to simplifying the calculation of absolute humidity is to assume a standard pressure, such as 1013 hPa (1 atm), rather than employing measured atmospheric pressure.

[0038] The present invention then applies a humidity correction as a function of the difference between this absolute humidity value and the normalized absolute humidity value to the smoke point (flame height) measurements taken to obtain equivalent measurements that are free of the effects of absolute humidity.

[0039] Thus, the present invention is adapted to the standard process of ASTM D1322-19 and functions even when calibrated and tested under different humidity conditions.

[0040] However, problems remain caused by the need to perform calibration at pressures close to the test pressure and therefore the frequent need to perform calibration before testing.

[0041] A second preferred embodiment of the present invention is employed to solve this problem, the purpose of which is to avoid the need to recalibrate every time the pressure changes by more than 0.7 kPa.

[0042] A second aspect of the present invention involves creating only one calibration set for seven reference mixtures and using the pressure correction factor f p The aim of this invention is to recalculate the calibration values ​​as a function of pressure by applying ≈ ...

[0043] However, even when the first aspect of the present invention, which corrects for humidity, is applied, the effect of pressure on the results is unknown, and it is unknown how to correct for the effect of pressure on the results. The ASTM D1322-19 standard does not teach a formula for applying a correction according to pressure fluctuations.

[0044] Therefore, the inventors investigated the effect of pressure (pressure alone, while holding constant variables due to other possible influences) on smoke point results. From this investigation, the inventors developed a pressure correction factor f to correct the measurement results as a function of pressure. p The pressure correction formula was derived using the pressure correction coefficient f p The pressure correction formula using can be empirically determined from data. Potentially, the pressure correction factor f pThis pressure correction formula is not taught or suggested in the process of the conventional ASTM D1322-19 standard. This pressure correction formula differs from the implicit pressure correction in the conventional ASTM D1322-19 standard. The conventional ASTM D1322-19 standard does not take humidity fluctuations into account, so it may not properly account for the pressure calculation. The conventional ASTM D1322-19 standard requires recalibration every time the pressure changes by more than 0.7 kPa, and even if recalibration is performed, humidity fluctuations are not taken into account.

[0045] The present invention can apply its pressure correction in different ways, as described herein. Smoke point measurements can be normalized to 1013 hPa (1 atm) or another pressure suitable for normalization. This normalization to 1013 hPa is not required, but it facilitates comparison of results. Therefore, preferably, the present invention applies its pressure correction and records a normalized calibration by correcting and then averaging three measurements at 1013 hPa (Method 1, described in more detail elsewhere in this specification) or by averaging three measurements as a function of pressure without correction (Method 2, described in more detail elsewhere in this specification). The present invention can then correct the test results as a function of pressure by correcting the measurements (to 1013 hPa) and applying the calibration value already stored at 1013 hPa corresponding to Method 1, or it is also possible to correct the test results without correcting the measurements as a function of pressure and recalculating the calibration value from 1013 hPa to the pressure under test corresponding to Method 2.

[0046] As a result, in accordance with Section 10 of the ASTM D1322-19 standard, the present invention performs an initial calibration of the device to calculate a correction factor, f (also known as the ramp factor). This correction factor, f, only corrects for inherent camera errors, such as imperfections in the camera, lens, or the specific settings of each device. Operators of the devices or methods of the present invention will maintain these calibrations for this reason and to maintain compliance with the standard. The calibration and ramp factor method described in this standard does not compensate for pressure, but rather applies deviations (whatever the cause) recorded during measurements at pressures close to the pressure of the reference mixture to the smoke point measurement results, specific to each device. When performing this initial calibration, the operator should be aware of ambient humidity, temperature, and pressure.

[0047] Thus, the present invention provides a test apparatus and method for determining the smoke point of hydrocarbons, the test apparatus comprising: an apparatus for determining smoke point conforming to the specifications of the ASTM D1322-19 standard; an imaging device for taking a series of digital images of the flame; an ambient relative humidity sensor for measuring relative humidity; an ambient temperature sensor for measuring the temperature; and a computer system connected to the imaging device, humidity sensor, and temperature sensor, programmed to analyze the digital image from the imaging device to measure the flame height, calculate the absolute humidity using the relative humidity and temperature measured by the temperature sensor and humidity sensor, correct the measured flame height as a function of the difference between the calculated absolute humidity and a normalized absolute humidity, and preferably correct the measured flame height as a function of the difference between the pressure during the flame height measurement and the normalized pressure. Typically, the normalized absolute humidity value is 0 gr / m 3 From 40gr / m 3 The value is preferably in the range of 7 gr / m 3 Typically, the normalized pressure value is between 800 and 1100 hPa, preferably 1013 hPa.

[0048] The present invention also provides a test apparatus for determining a pressure-corrected smoke point of a hydrocarbon, the test apparatus comprising: An apparatus for determining smoke point in accordance with the specifications of the ASTM D1322-19 standard; means for capturing a series of digital images of the flame; an ambient pressure sensor for measuring ambient pressure; and a computer system connected to the means for taking a series of digital images of the flame and connected to the ambient pressure sensor, the computer system being programmed to analyze the digital images taken by the means for taking the series of digital images to measure the flame height and to use the pressure measured by the pressure sensor to correct the measured flame point value of the hydrocarbon based on the ambient pressure measured by the ambient pressure sensor as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and a normalized ambient pressure. The present invention also provides a method of using the test apparatus to determine the pressure corrected smoke point of a hydrocarbon. [Brief explanation of the drawings]

[0049] The following figures are included to illustrate certain aspects of the present disclosure and should not be considered exclusive embodiments. The disclosed subject matter is capable of considerable modification, permutation, combination, and equivalents in form and function without departing from the scope of the present disclosure.

[0050] [Figure 1] 1 is an isometric view of an example of a prior art manual smoke point test device.

[0051] [Figure 2] 1 is a schematic diagram of an example of an automated smoke point test apparatus of the present invention for automatically correcting measured smoke point values ​​as a function of atmospheric conditions in accordance with the present invention.

[0052] [Figure 3] FIG. 1 is a schematic diagram of a computer.

[0053] [Figure 4] An example of a typical flame appearance is shown below.

[0054] [Figure 5] , [Figure 6] and [Figure 7] Figure 2 shows an example of the configuration of an automatic smoke point test device.

[0055] [Figure 8] 1 is a plot of humidity-based correction factor fh versus absolute humidity.

[0056] [Figure 9] and [Figure 10] 9 and 10 are examples of smoke point measurements used to derive the humidity-based correction factor fh. These graphs are examples of several measurements (represented by dots) at different absolute humidities, and the lines plotted in Figures 9 and 10, respectively, are trend curves calculated by EXCEL and used to illustrate the linearity of the effect; therefore, these lines are not the humidity correction factor fh described elsewhere herein.

[0057] [Figure 11] 1 is a plot of atmospheric pressure based correction factors versus atmospheric pressure.

[0058] [Figure 12] 1 shows an example of a calibration measurement by Pressure Correction Method 1 that can be incorporated into a smoke point test method according to the present disclosure.

[0059] [Figure 13] An example of a test measurement using pressure compensation method 1 is shown.

[0060] [Figure 14] 1 shows an example of a calibration measurement by Pressure Correction Method 2 that can be incorporated into a smoke point test method according to the present disclosure.

[0061] [Figure 15]An example of test measurement using pressure compensation method 2 is shown below. (Detailed Description)

[0062] FIELD OF THE DISCLOSURE This disclosure relates to hydrocarbon smoke point measurement devices, and more particularly to devices and methods for automatically correcting smoke point measurements according to atmospheric conditions.

[0063] The invention described herein is directed to an apparatus and method for automatically correcting smoke point measurements according to atmospheric conditions or parameters, such as atmospheric pressure, ambient temperature, and / or air humidity. The test apparatus includes humidity and ambient temperature sensors that measure atmospheric conditions (i.e., humidity and temperature), and such measurements (data) can be used to correct flame height measurements. Thus, the present invention typically corrects smoke point measurements (flame height in mm) from an existing calibration as a function of the difference between the current atmospheric humidity (converted to absolute humidity) measured by a humidity sensor integrated into the test apparatus and a normalized absolute humidity reference value. The present invention also preferably corrects smoke point measurements (flame height in mm) from an existing calibration as a function of the difference between the current atmospheric pressure measured by a pressure sensor, preferably integrated into the test apparatus, and the pressure recorded during calibration. Pressure measurements can also be used to correct flame height measurements in real time, typically normalizing smoke point measurements to 101.3 kPa (1 atm, 1013 hPa). Preferably, the selected normalized pressure value is 1013 hPa, but can be selected as any value between 800 and 1100 hPa.

[0064] The standard test method for the smoke point of kerosene and aviation turbine fuel is specified in ASTM D1322-19, Standard Test Method for Smoke Point of Kerosene and Aviation Turbine Fuel, ASTM International (April 2018), or its equivalent (collectively, the "Test Method"). The Test Method generally involves burning a fuel sample in a test apparatus and then measuring the resulting maximum flame height without smoke from the fuel sample. The test apparatus generally includes a sealed centered lamp calibrated against pure hydrocarbon blends with known smoke points. The test apparatus may be a manual or automatic test apparatus, and the Test Method specifies procedures for utilizing either test apparatus.

[0065] More specifically, the test method comprises the following steps: (i) preparing the test apparatus as described in Section 9 of the ASTM D1322-19 test method; (ii) calibrating the test apparatus as described in Section 10 of the ASTM D1322-19 test method; (iii) testing the fuel sample via the procedure set forth in Section 11 of the ASTM D1322-19 test method; (iv) calculating the smoke point as described in Section 12 of the ASTM D1322-19 test method; and (v) reporting the results as described in Section 13 of the ASTM D1322-19 test method. As noted above, the specific sequence of the foregoing steps may depend on whether the test apparatus is a manual or automatic test apparatus.

[0066] FIG. 1 shows an example of a conventional manual smoke point test apparatus 100 for testing fuel samples according to Section 11 of the ASTM D1322-19 test method.

[0067] Referring to FIG. 1, a conventional (manual smoke point) testing apparatus 100 includes a gallery 102 and a candle 104 movable into the gallery 102. The candle 104 includes a tank filled with a fuel sample (i.e., a test sample) and supports a wick W (see FIG. 2) that is saturated with the test sample when immersed in the candle's 104 tank. The candle 104 is then moved to place the fuel-saturated wick into the gallery 102, where it can be ignited for smoke point testing. A flame is thus generated within the gallery 102, and as shown, a scale 106 is provided within the gallery 102 for measuring the flame height. The gallery 102 may also be provided with a chimney 108 for exhausting the resulting combustion gases and fumes. The candle 104 is introduced into the gallery 102 before being ignited. Gallery 102 is provided with a candle holder 110 for receiving and supporting candle 104. A wick guide 112, in fluid communication with candle holder 110, is provided within gallery 102 for guiding and directing wick W into gallery 102. The position of candle 104 is vertically positionable within candle holder 110 to control or vary the amount of wick W extending from wick guide 112 and thereby the amount of wick W exposed within gallery 102 that is ignited during the test method. Adjusting the length of wick W extending from wick guide 112 can control the size of the flame required when performing the test method.

[0068] (Manual smoke point) When using the test apparatus 100, the flame height L of the test sample at the smoke point n is visually read (measured) via scale 106 and the flame height L is measured in accordance with Section 11.5 of the ASTM D1322-19 test method. n (i.e., L 1 , L 2 , L 3 ) three such observations are taken and then averaged together to calculate an average reading, "L." The average smoke point reading can then be multiplied by a correction factor, "f" (sometimes called the ramp factor), to calculate the corrected smoke point.

[0069] 2 is a schematic diagram of an automated smoke point testing apparatus 200 (hereinafter, test apparatus 200) configured to automatically correct measured smoke point values ​​as a function of atmospheric conditions in accordance with the present invention. Test apparatus 200 can be utilized to test fuel samples in accordance with the procedures of Section 11 (i.e., method for performing step iii) of the ASTM D1322-19 test method.

[0070] Test apparatus 200 includes digital camera 202 and computer 204. As shown in FIG. 3 , computer 204 includes a microprocessor 222, memory storage 224, one or more data / signal inputs 226 for receiving signals, e.g., from sensors 212, 214, 216 and digital camera 202, and one or more data / signal outputs 228 for reporting, e.g., the corrected smoke point of hydrocarbons or for controlling candle moving system 206. Digital camera 202 may be configured with a photosensitive CCD (charge-coupled device), CMOS (complementary metal-oxide semiconductor) image sensor, or other image sensor, preferably covering wavelengths ranging from ultraviolet to infrared. Optionally, digital camera 202 has a zoom. However, digital camera 202 may be configured differently. During the test method, a wick W of candle 104 is saturated with a fuel sample and then ignited to generate a flame F. A digital camera 202 is positioned relative to the gallery 102 and appropriately aimed to capture (record) an image (or video) of a flame F emanating from a wick W extending upward from the wick guide 112. The digital camera 202 is connected to a computer 204 having software for analyzing images received from the digital camera 202 to determine (measure) and record the height of the flame F. Additionally, the test fixture 200 measures the height of the flame F ("L"). n"). The candle movement system 206 may be a motorized conveyor system for elevating the candle 104 higher within the gallery 102, thereby increasing (or decreasing) the amount of wick W protruding from the wick guide 112, which has the effect of increasing (or decreasing) the size (height) of the flame F. The movement system 206 may move the candle 104 vertically, as indicated by the directional arrow V, to control the amount of wick W exposed within the gallery 102 for combustion. In the illustrated example, the candle 104 is positioned below (outside) the wick guide 112 with no flame F on the wick W, and at a height L above the wick W within the gallery 102. n 1 and 2. The wick is shown both when positioned inside the wick guide 112 with the flame F generated.

[0071] The test fixture 200 may further include an anti-infrared filter (not shown) positioned between the flame F and the digital camera 202 to capture a series of digital images.

[0072] Test rig 200 is configured to automatically correct the measured smoke point value as a function of atmospheric conditions, such as humidity and temperature, and typically also pressure. Referring again to FIG. 2 , test rig 200 is shown to include a relative humidity sensor 212 for measuring relative atmospheric humidity, a temperature sensor 214 for measuring ambient temperature, and a pressure sensor 216 for measuring ambient atmospheric pressure contemporaneously with the flame height measurement, such as on the day the digital image was taken or within one hour before or after the digital image was taken. Additionally, relative humidity sensor 212, temperature sensor 214, and pressure sensor 216 are in communication with computer 204 (e.g., connected by wire or via one or more of a variety of wireless communication protocols). Thus, computer 204 can receive data indicative of the current relative atmospheric humidity (via humidity sensor 212), the current ambient temperature (via temperature sensor 214), and the current atmospheric pressure (via pressure sensor 216). 2 shows that humidity sensor 212, temperature sensor 214, and pressure sensor 216 are integrated into test rig 200 and connected to computer 204. However, any one or more of relative humidity sensor 212, temperature sensor 214, and pressure sensor 216 need not be integrated into test rig 200. However, the use of an integrated pressure sensor prevents the test operator from entering erroneous pressure data (although convenient). If the automatic pressure correction of the present invention is not employed, the use of an integrated pressure sensor also ensures that the test operator performs a new calibration at pressure if a corresponding calibration value does not exist. Humidity sensor 212 and temperature sensor 214 can be used to compensate for the effect of humidity on the resulting smoke point measurement.

[0073] The humidity sensor 212, the temperature sensor 214, and the pressure sensor 216 may each be provided as separate components. However, one or more of the humidity sensor 212, the temperature sensor 214, and / or the pressure sensor 216 may be integrated and combined together as separate components. For example, the humidity sensor 212 and the temperature sensor 214 may be integrated together and provided as separate components. In another example, the temperature sensor 214 and the pressure sensor 216 may be integrated together and provided as separate components. Integrating the temperature sensor 214 with either the humidity sensor 212 and / or the pressure sensor 216 can compensate for internal temperature drift.

[0074] The pressure sensor 216 need not be integrated into the test fixture 400 and connected to the computer 204. Rather, the test operator can utilize other means of measuring atmospheric pressure, such as the optional air pressure acquisition system 208, and then manually input the atmospheric pressure into the computer 204, for example, via the data input 210.

[0075] Computer 204 includes software for automatically correcting for drift in the smoke point measurement results that may be caused by other atmospheric parameters such as temperature, humidity, and optionally pressure. Computer 204 automatically corrects the measured smoke point results as a function of either or both of the following: (a) the difference between the absolute humidity calculated from the relative humidity measured by humidity sensor 212 and the ambient temperature measured by temperature sensor 214, and / or (b) the difference between the current atmospheric pressure and a normalized pressure value measured by pressure sensor 216 during or contemporaneous with the test.

[0076] 5-7 also illustrate example configurations of a test apparatus 200 in accordance with one or more embodiments of the present disclosure. In the illustrated embodiment, the test apparatus 200 includes a housing 402, a power supply 404, and an electronics 406 (FIG. 2) that includes a computer 204 having a microprocessor 222 and memory 224 (FIG. 3) for performing calculations based on measurements from the sensors 212, 214, and 216 of the apparatus 200. Because the power supply 404 and / or the electronics 406 may generate heat within the housing 402, the test apparatus 200 may be provided with ventilation means. For example, the test apparatus 200 may include a fan 408 positioned to create an airflow 410 through the housing 402 from an air intake (or inlet) 412, where the airflow 410 is at ambient temperature and enters the housing 402, to an air exhaust (or outlet) 414, where the airflow 410, heated within the test apparatus 200, exits the housing 402 as heated airflow 419. Here, an air intake 412 is located on a chassis 416 below the housing 402, and a fan is located on a rear wall 418 of the housing 402, and draws airflow 410 that enters the housing 402 through the air intake 410, through the housing, and to an exhaust 414 from which the airflow is discharged. The test apparatus 200 also has a display screen 420, such as a touch screen, for inputting or receiving information or commands and for displaying information such as test results or other parameters.

[0077] One or more of the humidity sensor 212, temperature sensor 214, and / or pressure sensor 216 may be located proximate the air intake 412. In the illustrated embodiment, all of the sensors 212, 214, 216 are located inside the housing 402 at locations on the chassis 416 proximate the air intake 412. In this manner, the airflow 410 that enters the housing 402 and interacts with the sensors 212, 214, 216 is “fresh” air that is representative of the actual air temperature outside the housing 402. In this manner, the sensor (i.e., the temperature sensor 214) can analyze such “fresh” air for a temperature indicative of the actual ambient air temperature before it passes through the housing 402 to cool various internal components of the test fixture 200, such as the power supply 404 and / or electronics 406, which may subsequently heat the “fresh” air above the actual ambient air temperature. Furthermore, by positioning the air intake(s) 410 below the test fixture 200, for example, in a position that allows them to draw air from above the chassis 416 as shown, it is possible to measure an air temperature that is most representative of the actual ambient air temperature of the air that will ultimately be combusted in the lamp during test preparation.

[0078] Figure 6 shows the test fixture 200 with the elements of Figures 2 and 5 when the candle 104 is in a first position. Figure 7 shows the test fixture 200 with the elements of Figures 2 and 5 when the candle 104 is in a second position inserted into the test fixture 200. To use the test fixture 200, the candle 104 is moved from its first position, away from the test fixture 200 shown in Figure 6, to its second position on the conveyor of the candle movement system 206 of the test fixture 200 shown in Figure 7. If necessary, enter all sample details and begin testing, which will lead to automatic measurement of at least some of the current atmospheric parameters. For details, refer to the equipment manufacturer's instructions. The candle is automatically introduced into the lamp and undergoes the flame appearance sequence specified in Section 11.5 of ASTM D1322-19. This includes ignition of the candle 104. The candle level is then automatically adjusted so that the flame is approximately 10 mm high and the lamp burns for 5 minutes. After a 5-minute stabilization period, the candle is automatically raised until a smoke tail appears, then slowly lowered through the following sequence of flame appearances: long tip; slight visible smoke; unstable, bouncing flame. Figure 4 shows flame "F." In Figure 4, flame "A" is too high, flame "B" is normal, flame "C" is too low, and "X" is the base of the flame. As shown in Figure 4 (flame A), a long, pointed tip appears with the sides of the tip concave upward. The pointed tip has just disappeared, leaving a very slight, dull flame, as shown in Figure 4 (flame B). A jagged, unstable, bright flame may be observed near the tip of the true flame; these should be ignored. A well-rounded tip, as shown in Figure 4 (flame C). Determine the height of flame B to the nearest 0.5 mm using the manual method and to the nearest 0.1 mm using the automated method. Record the observed height.

[0079] The software in the apparatus 200 analyzes the flame image captured by the digital camera. The software automatically detects the flame shape corresponding to Flame B in Section 11.5.3 of ASTM D1322-19, also shown in Figure 4. The software determines the height of Flame B to the nearest 0.1 mm. The test apparatus 400 records the observed height. When the candle conveyor lowers the candle 104, the flame automatically extinguishes and returns to its resting position. Due to the flame height resolution of the digital camera, the flame height is recorded to the nearest 0.1 mm. The apparatus makes three separate observations of the flame height at the smoke point by repeating the flame appearance sequence specified in Section 11.5 of ASTM D1322-19. If these values ​​vary by more than 1.0 mm, the test apparatus 400 will alert the test operator. Repeat the test with a new sample and a different wick. The candles 104 are removed from the conveyor, rinsed with heptane, and purged with air to prepare them for reuse.

[0080] Computer 204 automatically corrects the measured smoke point results as a function of absolute humidity using data measured by humidity sensor 212, along with temperature data (e.g., from temperature sensor 214) and pressure sensor 216 or barometric pressure acquisition system 208. Thus, aspects of the present disclosure improve the repeatability of the test method and the accuracy of the smoke point results by factoring humidity into the smoke point calculation.

[0081] Humidity is an atmospheric condition that indicates the amount of water molecules contained in the air. Humidity hinders the combustion of kerosene, and therefore has a negative effect on the smoke point value. The density of water vapor in the air is called absolute humidity (AH), and its unit is kg / m 3The amount of water vapor present in the air, expressed as a percentage of the amount required to saturate the air at the same temperature, is called relative humidity (RH) and is expressed as a percentage (%RH). AH can be calculated based on RH, ambient air temperature (T), and atmospheric pressure (P). Thus, test fixture 200 can include a humidity sensor 212 to measure RH, a temperature sensor 214 to measure the ambient air temperature T, and a pressure sensor 216 to measure the current atmospheric pressure P, and computer 204 can then use these measurements to calculate AH (via a conversion formula from RH to AH; the conversion formula from RH to AH is known). An example calculation of AH is provided below in the section entitled "Calculation Example - Relative Humidity to Absolute Humidity Conversion Formula." Computer 204 also uses these measurements to calculate the smoke point by using a humidity correction factor f when performing the smoke point calculation. h (i.e., AH-based correction) can be applied to correct the measured flame height as a function of the difference between the calculated absolute humidity and the normalized absolute humidity value.

[0082] Atmospheric pressure has been observed to have little effect on the AH calculations (less than 0.1% for a 250 hPa variation).

[0083] It has also been observed that the ambient air temperature T can have a significant effect on the calculation of results. Therefore, the temperature sensor 214 is appropriately positioned relative to the test fixture 200 (and its envelope) so that the measured ambient air temperature T represents the actual air temperature of the environment in which the test method is performed.

[0084] The present invention allows the test apparatus 200 to be recalibrated to smoke test measurements at a standard (normalized) humidity, where the normalized humidity value is 0 gr / m 3 From 40gr / m 3 A value in the range of 7gr / m 3 is.

[0085] In the illustrated example, the test apparatus 200 may utilize a measure of atmospheric pressure, such as a pressure sensor 216, or may optionally utilize an external air pressure acquisition system 208 instead of the pressure sensor 216. The pressure sensor 216 would communicate an ambient air pressure value to the computer 204 (or other control unit). The external air pressure acquisition system 208 would obtain (receive) the ambient pressure value. An operator would then manually communicate (input or enter) the ambient air pressure value from the external air pressure acquisition system 208 to a data input 210 of the computer 204 (or other control unit). For example, the air pressure acquisition system 208 may include an external (or separate) barometer for measuring ambient air pressure and obtain a measured air pressure value, but it does not directly provide this measured air pressure value to the computer 204. The test operator may manually enter this measured air pressure value into a data input 210 integrated with the computer 204 so that the computer 204 can use it. Thus, data input 210 may consist of a touch screen, keypad, dial, or other means by which a test operator can manually enter data for use by computer 204 .

[0086] According to a preferred embodiment of the present invention, the computer 204 calculates a pressure correction factor "f p The pressure compensation is automatically performed to correct the flame height measured using the "pressure compensation" method. This automatic pressure compensation eliminates the need for recalibration when pressure changes greater than 0.7 kPa, as required by the ASTM D1322-19 standard. Thus, this automatic pressure compensation facilitates the performance of the test method by eliminating the need for the test operator to perform a new calibration when calibration values ​​at the current pressure ±0.7 kPa are not available, for example, because they are not stored in the calibration database.

[0087] Thus, when a method or apparatus of the present invention employs pressure compensation according to the present invention, it is not necessary to select a calibration at the pressure closest to the measurement.

[0088] However, if a user (operator) performs several calibrations on the same reference mixture and wants to select the calibration at the pressure closest to the measurement, the user can still select the calibration at the pressure closest to the measurement. The present invention allows the test apparatus 200 to recalibrate to smoke test measurements at the standard, correct atmospheric pressure, typically 101.3 kPa (1 atm). The computer 204 can utilize information entered via the pressure sensor 216 or data input 210 for use in automatically calibrating the test apparatus 200 to smoke test measurements at the standard, correct atmospheric pressure, typically 101.3 kPa (1 atm). In this manner, the computer 204 or the barometric pressure acquisition system 208 can be associated with a calibration database for selecting the correct calibration value when automatically calculating the correction factor (ramp factor "f") described below. The calibration database can be stored in the memory of the computer 204.

[0089] The present disclosure can also provide an apparatus and method whereby the computer 204 automatically calculates calibration data at the current atmospheric pressure measured by the pressure sensor 216 during a test performed using a stored calibration value normalized to 1013 hPa.

[0090] Performing smoke point tests, calculating and correcting smoke point under atmospheric conditions

[0091] Thus, the smoke point value is the measured flame height L at the edge of the flame. nis the limit of the height before smoke is generated by the combustion of the test sample. FIG. 4 shows flame F, which has a common flame base "X," and examples of various flame fluctuations extending from flame base X. In particular, FIG. 4 shows flame fluctuation "A," which has a long, pointed tip with the sides of the tip appearing slightly concave upward. Also shown in FIG. 4 are flame fluctuations "B" and "C," where flame fluctuation B has a slightly blunt flame tip and flame fluctuation C has a well-rounded tip. Flame fluctuation A extending from flame base X is too large, while flame fluctuation C is too small. Thus, the test procedure instructs the test operator, using manual device 100, to identify when flame F has a flame shape corresponding to flame fluctuation B and record the observed height to the nearest 0.5 mm.

[0092] When using test apparatus 200, software in computer 204 analyzes images of flame F taken by digital camera 202 and automatically detects when flame F has a flame shape corresponding to flame fluctuation B, and then the automated apparatus 200 calculates the height L of that flame F. n Calculate the height L in 0.1mm increments. n The digital camera 202 views the flame F through a window which may include a filter, such as an anti-infrared filter, between the flame and the digital camera.

[0093] As mentioned above, the ASTM D1322-19 test procedure determines the flame height at the smoke point (L) by repeating the sequence of flame appearances specified in Section 11.5 of the ASTM D1322-19 test procedure. 1 , L 2 , L 3 ) are required to be observed three separate times. These observations or readings are then averaged together to calculate the average reading, "L."

[0094] According to ASTM D1322-19, the final smoke point is calculated (to the nearest 0.1 mm) according to equation (2) in section 12 of ASTM D1322-19 as "Smoke point = L x f." In this equation, "L" equals the average of three individual readings or observations of the flame height, Ln, and "f" is a correction factor (sometimes called a ramp factor). As noted above, the correction factor "f" is calculated consistent with section 10 (i.e., step ii) of the ASTM D1322-19 test procedure prior to performing the test procedure (step iii).

[0095] However, in the present invention, the smoke point is calculated not only using the formula (2) of ASTM D1322-19 but also using the humidity correction factor f h and optionally a pressure correction factor f p It is usually calculated (to the nearest 0.1 mm) via a modified approach, corrected for pressure by . Instrument calibrations that specify a correction factor "f" to account for errors related to the camera itself used to measure the smoke point, such as camera and lens failures and adjustment tolerances, are more accurate because they calibrate using humidity and preferably pressure corrected smoke point values.

[0096] When using the test apparatus 200, the digital camera 202, the computer 204 and its associated software, and the mobile system 106 work together to read and record three separate observations of the flame height at the smoke point in accordance with Section 11.6 of the ASTM D1322-19 test method. The computer 204 measures the flame height L 1 ,L 2 ,L 3 The three readings or observations are automatically averaged to calculate the average reading "L", and then the humidity correction factor "f h The computer 204 optionally calculates the smoke point by multiplying the pressure correction factor "f p " is also calculated.

[0097] The result of the formula may then be reported as the smoke point of the sample tested and rounded to the nearest 0.1 mm in accordance with section 13 (i.e., step v) of the test method.

[0098] Rather than correcting the average flame height measured, the test apparatus 200 corrects for each observed flame height L n may be corrected as a function of the AH (absolute humidity) value. As previously mentioned, the test method instructs the operator to make three separate observations of the flame height at the smoke point, and it is observed that increasing the AH results in a corresponding decrease in the smoke point value. In this way, humidity correction can be applied in real time to correct each of the three observed flame heights. In particular, computer 204 calculates the flame height L n Each observation of can be multiplied by the humidity correction and then the average reading L can be calculated.

[0099] FIG. 8 illustrates the humidity correction factor f as a function of absolute humidity (AH) in accordance with one or more embodiments of the present disclosure. h In this plot, the defined reference value is 7 gr / m, which corresponds to 40.4% RH at 20°C. 3 where the humidity correction factor f is calculated based on the specific absolute humidity (AH) represented on the x-axis of the plot. h A curve 500 has been derived that defines a specific value of 7 gr / m. As can be seen in FIG. 8, the normalized value of AH is 3 Then, the correction factor f h is 1. The computer 204 calculates a humidity correction factor f that corresponds to the actual humidity (AH) encountered during a particular use of the test apparatus 200, which can be calculated using data measured via one or more sensors. h The curve 500 (or one or more like it) may be stored in the memory of the computer 204 so that the computer 204 can determine the flame height L. 1 ,L 2 ,L 3 Each of these factors takes into account the effect of humidity on the flame height, and the observed flame height L n (i.e., L 1 ,L 2 ,L 3 ) with humidity correction factor f h (i.e., humidity-corrected observed flame height fh *L 1 ,f h *L 2 ,f h *L 3 ). humidity f h *L 1 ,f h *L 2 ,f h *L 3 The three flame height observations corrected based on can be averaged together to obtain an average reading L. Thus, the average reading L can be obtained using equation (3) below:

[0100]

number

[0101] Curve 500 in Figure 8 is a humidity correction curve as a function of absolute humidity AH. Curve 500 was established by performing various smoke point measurements under different humidity conditions, for example in a room or test environment suitable for controlling humidity and temperature. Various smoke point measurements were performed using the procedure specified in Section 11 for the seven reference fuel blends (i.e., Mix 1 to Mix 7) specified in Section 7.4 and several kerosene samples. These various smoke point measurements allowed the determination of the humidity correction factor f h can be estimated as a function of absolute humidity (AH) and measured flame height. Figures 9 and 10 are plots of the data points and plot lines through the data points of test data showing smoke point measurement tests conducted on ASTM D1322-19 Mix 7 and kerosene (Kero ADS05). This plot of test data can be used to estimate the humidity correction factor f as a function of absolute humidity (AH) and measured flame height. h The calculation formula for f is established. These graphs are examples of several measurements (represented by dots) at different absolute humidities. The plotted lines in Figures 9 and 10 are trend curves (straight tread lines) calculated in Excel, respectively, and are used to show the linearity of the effect. This line is used to calculate the correction factor f h Using this experimental and test data, the humidity correction factor f hEmpirical formulas are sometimes established for the calculation of the humidity correction factor f h can be calculated using the following equation (4):

[0102]

number

[0103] The humidity corrected average flame height reading L can then be multiplied by the ramp factor f to obtain the final smoke point result.

[0104] How to apply correction based on pressure

[0105] Thus, the ASTM D1322-19 test procedure determines the flame height (L) at the smoke point by repeating the sequence of flame appearances specified in Section 11.5 of the ASTM D1322-19 test procedure. 1 , L 2 , L 3 ) are required to make three separate observations. These observations or readings are then averaged to calculate an average reading, "L." The average reading, "L," is then multiplied by a correction factor, "f" (the ramp factor), to correct for ambient pressure and arrive at the final smoke point.

[0106] As mentioned above, the flame height L recorded during calibration n Measurements of flame height L may incorporate some bias due to various sources. Bias may be introduced by the test instrument itself and / or other environmental considerations. For example, the flame height L n The bias may arise from errors in the measurement itself or from possible imperfections in the optics of the camera 202. In some cases, this bias may be so small that it can be considered a constant.

[0107] As mentioned above, atmospheric pressure is another atmospheric condition that affects smoke point measurements. In particular, higher atmospheric pressures result in lower smoke point values.

[0108] As mentioned above, an operator typically performs an initial calibration to obtain the correction factor "f" of ASTM D1322-19. However, in its preferred embodiment, the present invention provides a pressure correction factor "f" to avoid the need for recalibration when the pressure difference at the time of the initial calibration relative to the current measured pressure is greater than ±0.7 kPa (either below 0.7 kPa or above 0.7 kPa). p " is adopted. ASTM D1322-19 records the pressure during calibration when calculating the ramp factor "f" and at the time of the current measurement. ASTM D1322-19 requires recalibration if the pressure difference between the current measured pressure and the pressure at the time of calibration is greater than ±0.7 kPa.

[0109] The correction factor "f" for the ASTM D1322-19 test method is calculated from measurements made under identical pressure conditions (within ±0.7 kPa) for the reference fuel blends (or mixtures) specified in Section 7.4 and Table 1 of the ASTM D1322-19 test method. Table 1 of the ASTM D1322-19 test method identifies seven different reference fuel blends (i.e., Mix 1, Mix 2, Mix 3, Mix 4, Mix 5, Mix 6, and Mix 7), each consisting of a different blend ratio (%V / V) of toluene and isooctane. A standard smoke point (@101.3 kPa) is provided for each of the seven different reference fuel blends. The test operator must select two reference fuel blends whose values ​​frame the value measured on the fuel sample being tested. The calibration values ​​for the seven different reference fuel blends can be incorporated into a calibration database stored in the memory of computer 204. However, as noted above, this test method requires a new calibration of the test equipment if the pressure varies by more than 0.7 kPa (i.e., ±0.7 kPa) at the time of the manual test method (see Section 10.1), or if there are no stored calibration values ​​in the calibration database within 0.7 kPa of atmospheric pressure at the time of the automatic test method (see Section 10.2.2).

[0110] For example, before running a test method, a test operator records the barometric pressure and checks a calibration database for calibration values ​​associated with the recorded pressure or within ±0.7 kPa of the recorded pressure. If a calibration value exists at the recorded pressure ±0.7 kPa, the test operator can run the test method, and the automated system will select two calibration values ​​that bracket the smoke point of the tested sample. However, if calibration values ​​for the seven blends (Mix 1 through Mix 7) do not exist in the calibration database at the recorded pressure ±0.7 kPa, the test method instructs the operator to perform a new calibration at the recorded pressure, which is time-consuming and inconvenient given the often-busy schedules of laboratories. Thus, a test operator faced with a command to perform a new calibration may simply enter (use) the barometric pressure for which a calibration value exists, rather than using the value corresponding to the actual pressure, resulting in biased results.

[0111] The present invention uses the humidity correction factor f h This invention also provides an apparatus and method that improves upon the consideration of pressure as in ASTM D1322-19 by providing an additional correction for humidity by employing a ramp factor f, where f is the flame height xf h In this alternative, the test apparatus 200 of the present invention includes a pressure sensor 216 for measuring the current atmospheric pressure "P" in real time, and the computer 204 subsequently uses a pressure-based correction (i.e., a pressure-based correction "f") when performing the smoke point calculation. p This measurement data can be preferably used to apply the correction factor "f" (or "f"). Although there is an initial calibration according to ASTM D1322-19, this improved method eliminates the need to re-calibrate (or perform and save previous calibrations) to determine the correction factor "f" every time the pressure fluctuates by more than ±0.7 kPa. Furthermore, this correction factor "f", which takes into account the errors of the camera itself used to measure the smoke point, such as camera and lens malfunctions and adjustment tolerances, is more accurate because it is calibrated using the smoke point value corrected for humidity and pressure.

[0112] Pressure-based compensation "f p " can be applied in two different ways. Test apparatus 200 can be configured to perform either pressure-based correction selected by the test operator.

[0113] In the first method, the test operator calculates the three observed flame heights L in the same manner as described above for the application of the humidity-based correction. n One can choose to apply a pressure-based correction to each of the measurements in real time. In this way, the three flame height observations L 1 ,L 2 ,L 3 Each of these has a pressure-based correction "f p " and averaged together to obtain the average measurement L. Thus, the average reading L corrected for pressure is obtained using equation (5) below:

[0114]

number

[0115] The final smoke point result can then be obtained by multiplying the pressure corrected average flame height reading L by the ramp factor f.

[0116] The first method of applying pressure-based correction involves correcting flame height measurements in real time in a manner similar to applying humidity-based correction. Here, each flame height measurement is corrected to obtain a height at a normalized pressure, e.g., 1013 hPa. Therefore, for a calibration using a mixture, a reference value for that specific normalized pressure (e.g., 1013 hPa) is recorded. In this way, the calibration only includes biases (e.g., optical system imperfections) inherent to the test apparatus 200. Then, during normal test preparation of kerosene samples, the flame height Ln is also corrected in real time as a function of pressure, resulting in a measurement equivalent to the normalized pressure (e.g., 1013 hPa). Therefore, the correction calculation according to the ramp factor "f" described in the ASTM D1322-19 test method uses the calibration using values ​​at the normalized pressure (e.g., 1013 hPa). Here, a single calibration set containing seven mixtures can be utilized, and no further calibration is required.

[0117] FIG. 11 illustrates a graph of the atmospheric pressure correction factor "f" as a function of atmospheric pressure (P) in hectopascals (hPa), in accordance with one or more embodiments of the present disclosure. p 1 is a plot of correction factor versus atmospheric pressure showing the pressure correction factor "f" based on a specific atmospheric pressure (P) represented on the x-axis of the plot. p 2 shows a derivative curve 600 that defines a particular value for ". Curve 600 (or something similar) may be stored within computer 204 so that computer 204 can calculate a pressure-based correction factor "f" that corresponds to the actual pressure "P" encountered during a particular use of the test apparatus and measured via pressure sensor 216. p Then, the computer calculates the observed flame height L n For each of the pressure-based correction factors, f p " and multiplied by 3 times the individual flame height observations (i.e., L 1 , L 2 , L 3) consider the effect of atmospheric pressure on the flame height. In this way, the three flame height observations L 1 , L 2 , L 3 Each of these has a pressure-based correction "f p " and then averaged together to obtain an average reading L. The average reading L is obtained using equation (5) above.

[0118] The average reading "L" is then multiplied by the ramp factor "f" to obtain the final smoke point via equation (2) above. h Similar to forming a plot of f vs. σ, a linear regression or other suitable analysis can be applied to the test data obtained from the test using the reference material where only pressure was varied to obtain a plot of f as shown in Figure 11. p A plot of the

[0119] 12 and 13 show an example of a process for implementing a first method of applying humidity-based correction, pressure-based correction, and ramp factors for calibration and test measurements with Pressure Correction Method 1. FIG. 12 shows a calibration measurement using Pressure Correction Method 1. In this method, there is one calibration per reference mixture, i.e., seven calibrations. FIG. 12 shows that this process may generally include a calibration measurement using Pressure Correction Method 1 with a first segment 702 (i.e., calibration measurement segment 702) where the calibration measurement is performed or carried out. This means that a first set of calibration steps 706 may include a calibration measurement using Pressure Correction Method 1 with a humidity-based correction (e.g., 985 hPa and AH 12.5 g / m 3 (2) measuring the flame height and applying a humidity correction factor f h Multiply by the humidity-corrected flame height (e.g., 7 g / m 3 and then applying a pressure correction factor f pto calculate a humidity and pressure corrected flame height (e.g., at a pressure equivalent to a pressure measurement of 1013 hPa). In the illustrated example, the calibration measurement segment 702 is performed for each of the seven reference fuel blend mixtures, such that seven calibrations are performed. Thus, the calibration measurement segment 702 is performed seven separate times, once for each of the seven reference fuel blend mixtures. The flame height L n The first set of calibration steps 706, which involves measuring three separate observations of flame height (L 1 , L 2 , L 3 In the illustrated example, the first set of calibration steps 706 calculates the flame height L n the humidity correction factor f h and then multiplying the resulting product by a pressure-based correction f p (i.e., L n *f h *f p ) steps. Thus, the first set of calibration steps 706 also includes three flame height measurements, each corrected based on humidity and pressure (i.e., humidity and pressure corrected flame height measurements. L 1 *f h *f p ;L 2 *f h *f p ;L 3 *f h *f p ) The calibration measurement segment 702 then calculates three humidity and pressure corrected flame height measurements (i.e., L = [(L 1 *f h *f p )+(L 2 *f h *f p )+(L 3 *f h *f p )] / 3). The calibration measurement segment 702 then includes storing or saving this calibration data in the memory of the computer 204 and / or in a calibration database.

[0120] 13 illustrates a test measurement using pressure compensation method 1 with a second segment 704, in which a test measurement is performed or carried out (i.e., test measurement segment 704). Thereafter, as shown in FIG. 13, a test sample can be measured according to test measurement segment 704. Test measurement segment 704 observes the flame height (i.e., flame height L n The first set of test steps 708 is performed three separate times to obtain three separate observations of flame height (L 1 , L 2 , L 3 In the illustrated example, the set of test steps 708 calculates the flame height L n the humidity correction factor f h and then multiplying the resulting product by a pressure-based correction f p (i.e., L n *f h *f p ) steps. Thus, the first set of test steps 708 includes three humidity and pressure corrected flame height measurements (i.e., humidity and pressure corrected flame height measurements. L 1 *f h *f p ;L 2 *f h *f p ;L 3 *f h *f p ) The test measurement segment 704 then obtains three humidity and pressure corrected flame height measurements (i.e., L = [(L 1 *f h *f p )+(L 2 *f h *f p )+(L 3 *f h *f p)] / 3). The test operator or computer 204 may then select two calibrations that bracket (or sandwich) the average reading L and use equation (1) to calculate the lamp correction factor "f" using the two calibrations that bracket / surround the measurement. The test operator or computer 204 then calculates the final smoke point via equation (2) (i.e., smoke point = L * f) and can later store and / or report the final result for smoke point in computer 204 memory.

[0121] It should be noted that although the processes illustrated in FIGS. 12 and 13 correct based on humidity and pressure, in other examples, pressure-based correction may be utilized without performing humidity-based correction.

[0122] Alternatively, in a second method, the test operator may choose to apply a pressure-based correction to the calibration measurement results at a normalized pressure value (e.g., 1013 hPa (hectopascals)) so that the ramp factor correction factor "f" obtained from the calibration measurement includes a pressure correction rather than being applied to the flame height measurement. In this way, flame height measurement errors can be corrected during calibration, resulting in one set of calibration values ​​for each of the seven reference fuel blends at a given pressure. Then, during normal testing on a test sample (e.g., kerosene), the measured heights are not corrected according to pressure in this second case, but the calibration values ​​needed to calculate the ramp factor are calculated by correcting the values ​​recorded at 101.3 kPa as a function of the pressure values ​​measured during testing.

[0123] 14 and 15 illustrate an example process for implementing an alternative second method of applying humidity-based correction, pressure-based correction, and ramp coefficients to calibration and test measurements using Pressure Compensation Method 2. FIG. 14 shows a calibration measurement using Pressure Compensation Method 2. With this method, there are seven calibrations, one per reference mixture. FIG. 15 shows a test measurement using Pressure Compensation Method 2. As can be seen in FIG. 14, this second method of applying pressure-based correction applies the humidity-based correction f to the calibration values ​​used to calculate the ramp correction factor "f." h and pressure-based correction f p This is then multiplied by the average reading "L" to get the final smoke point, as seen in Figure 15, where the individual flame height measurements L during testing and calibration are n No pressure-based correction is applied to f p is applied to the average calibration measurement result to obtain a value at a normalized pressure, e.g., 1013 hPa. Therefore, this method uses a calibration value stored at a normalized pressure (e.g., 1013 hPa). Since the test is performed at the current ambient pressure, the smoke point measurement is performed at this pressure. In calculating the ramp factor "f," the calibration value must be within ±0.7 kPa of the current pressure. The system uses the calibration value recorded at 1013 hPa as a base and applies a correction corresponding to the pressure difference to generate a calibration value at the required pressure (the test pressure). Select two calculated calibration values ​​that bracket (enclose) the flame measurement of the test specimen, then calculate the ramp factor "f" using equation (1), multiply by the average reading L as described in equation (2) to generate the final smoke point, and the final result can be reported.

[0124] Thus, the second method of applying pressure-based correction is identical to the standard test method, except that instead of a calibration performed specifically at the desired pressure, a calibration calculated from the stored calibration values ​​normalized to 1013 hPa is used, as illustrated in FIG. 14.

[0125] Specifically, the calibration value recorded for 1013 hPa is divided by a pressure correction factor corresponding to the pressure measured during the test to obtain the calibration value at the test pressure. Two calibration values ​​that bracket or surround the flame measurement of the test sample are selected and used as per ASTM standards to calculate the ramp factor via equation (1). For example, the error in the flame height measurements can be corrected during calibration to obtain one set of calibration values ​​for each of seven different reference fuel blends at a given pressure. Then, when performing the test method on a test sample (e.g., kerosene), this second method involves dividing the measured height L by the n is not corrected for pressure (except for the measured height L n are the humidity correction coefficients f h (The humidity may be corrected for by multiplying by and then averaging to obtain the average value L), but the calibration value required to calculate the ramp factor f will be calculated by correcting the value recorded at 101.3 kPa as a function of the pressure value measured during the test.

[0126] 14 illustrates an example process for a calibration measurement using Pressure Compensation Method 2 for implementing a second method of applying pressure-based compensation. As shown, this process may generally include a first segment 802 in which a calibration measurement is performed or executed (i.e., Calibration Measurement Segment 802). FIG. 15 illustrates a second segment 804 in which a test measurement is performed or executed (i.e., Test Measurement Segment 804).

[0127] In FIG. 14, the calibration measurement segment 802 is performed for each of the seven reference fuel blend mixtures, such that seven calibrations are performed. In other words, the calibration measurement segment 802 is performed seven separate times, once for each of the seven reference fuel blend mixtures. The calibration measurement segment 802 is performed for the following measurements (e.g., 1022 hPa and AH 8.1 g / m 3 The first set of calibration steps 806 includes measuring the flame height (L 1 , L 2, L 3 ) is obtained. A first set of calibration steps 806 then involves generating humidity corrected flame height measurements, where the flame height measurements (L 1 , L 2 , L 3 ) are the humidity correction coefficients f h Multiply each measured flame height by 1 to obtain a humidity-corrected flame height (e.g., 7 gr / m 3 AH measurement), where, for example, the first set of calibration steps 806 thus corrects for moisture by calculating the AH value for each measured flame height L n the humidity correction factor f h Step of multiplying (i.e., L n *f h ), and a first set of calibration steps 806 includes three humidity-corrected flame height measurements (i.e., humidity-corrected flame height measurements: L 1 *f h ;L 2 *f h ;L 3 *f h ) The calibration measurement segment 802 then calculates the average reading L of the humidity corrected flame height measurements (i.e., L = [(L 1 *f h )+(L 2 *f h )+L 3 *f h )] / 3). The calibration measurement segment 802 then includes storing or saving this calibration data in the memory of the computer 204 and / or in a calibration database.

[0128] Although the process illustrated in Figures 14 and 15 corrects based on humidity and pressure, in other examples, pressure-based correction can be utilized without performing humidity-based correction.

[0129] 15, the test sample can be measured according to test measurement segment 804. Test measurement segment 804 includes the steps of taking flame height observations (i.e., flame height L n, which includes a first set of test steps 808 associated with measuring three separate observations of flame height (L ) that can be averaged together to obtain an average reading L . 1 , L 2 , L 3 In the illustrated example, the first set of test steps 808 are performed three times to obtain the measured flame height L n the humidity correction factor f h (i.e., L n *f h ) is multiplied by the humidity-corrected flame height measurements (i.e., humidity-corrected flame height measurements: L 1 * f h ;L 2 *f h ;L 3 *f h ) The test measurement segment 804 then calculates an average reading L from the three humidity-corrected flame height measurements (i.e., L = [(L 1 *f h )+(L 2 *f h )+(L 3 *f h )] / 3). The test operator or computer 204 then uses the calibration data recorded at normalized pressure (e.g., 1013 hPa) and the pressure-based correction f p In particular, the calibration data can be calculated by applying a pressure-based correction f to the calibration data recorded during the calibration measurement segment 802. pThe smoke point is calculated during the test measurement segment 804 by dividing by L*f. The test operator or computer 204 can then select two calibration values ​​that bracket (or sandwich) the average reading L (of the three humidity-corrected flame height measurements) and use equation (1) to calculate the lamp correction factor "f" using the two calibrations that bracket / surround the measurement. The test operator or computer 204 can then calculate the final smoke point via equation (2) (i.e., smoke point = L*f) and later store and / or report the final result for the smoke point in computer 204 memory.

[0130] Thus, in either of the two methods described above, the need to make more than one calibration batch using seven different reference fuel blends is eliminated, and the constraint of recalibrating every time the pressure changes by more than ±0.7 kPa is eliminated, making the test method simpler and easier to perform.

[0131] The disclosed systems and methods are thus well adapted to achieve the objects and advantages mentioned, as well as those inherent therein. The specific embodiments disclosed above are merely illustrative, as the teachings herein may be practiced in modified and different but equivalent manners, as will be apparent to those skilled in the art having the benefit of such teachings. Moreover, no limitations are intended to the details of construction or design shown herein, other than as described in the following claims. It is therefore evident that the specific example embodiments disclosed above may be altered, combined, or modified, and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element not specifically disclosed herein and / or any optional element disclosed herein. Specific Embodiments of the Invention

[0132] The following paragraphs present specific embodiments of the present invention.

[0133] Paragraph A: The present invention provides a test apparatus for determining the smoke point of a hydrocarbon, the test apparatus comprising: Apparatus for determining smoke point in accordance with the specifications of the ASTM D1322-19 standard; means for capturing a series of digital images of the flame; an ambient relative humidity sensor for measuring relative humidity; an ambient temperature sensor for measuring the temperature; a computer system connected to a means for taking a series of digital images of the flame, connected to a humidity sensor, and connected to a temperature sensor, the computer system being programmed to analyze the digital images taken by the means for taking the series of digital images to measure the flame height, calculate the absolute humidity using a combination of the temperature measured by the ambient temperature sensor and the relative humidity measured during the test by the relative humidity sensor, and correct the measured flame height as a function of the difference between the calculated absolute humidity and a normalized absolute humidity value.

[0134] The test apparatus of paragraph A may include any of the following modifications:

[0135] The testing apparatus of paragraph A further comprises an ambient pressure sensor connected to a computer system, the computer system being capable of correcting the measured flash point value of the hydrocarbon as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized pressure value.

[0136] In the test apparatus of paragraph A, the ambient temperature sensor may be part of the ambient relative humidity sensor or may be separate from the ambient relative humidity sensor.

[0137] The testing apparatus of paragraph A further comprises an ambient pressure sensor connected to a computer system, the computer system being capable of correcting the measured flash point value of the hydrocarbon based on the ambient pressure measured by the ambient pressure sensor.

[0138] In the test apparatus of paragraph A, the means for taking a series of digital images of the flame may comprise a digital camera.

[0139] The test apparatus of paragraph A may further comprise an anti-infrared filter disposed between the apparatus for determining a smoke point conforming to the specifications of the ASTM D1322-19 standard and the means for taking a series of digital images.

[0140] In the test device of paragraph A, the normalized humidity value is 0 gr / m 3 From 40gr / m 3 may be in the range of 7 gr / m 3 is.

[0141] In the test apparatus of paragraph A, the means for taking a series of digital images of the flame may comprise a digital camera. Here, an apparatus for determining smoke point in accordance with the specifications of the ASTM D1322-19 standard comprises a candle for holding a wick, a scale for measuring flame height, a gallery configured to take digital images of the flame and the scale, and a candle movement system for adjusting the height of the flame from the wick of the candle.

[0142] The test equipment of paragraph A: Power supply and; a housing; and the housing comprising: A digital camera and an ambient relative humidity sensor; an ambient temperature sensor; The system may further comprise a computer system connected to the means for capturing a series of digital images, the computer system comprising an electronic device including a microprocessor.

[0143] In the test apparatus of paragraph A, the test apparatus may include ventilation means, an air intake port for introducing airflow into the test apparatus housing, and an air exhaust port for expelling the airflow heated within the test apparatus housing out of the housing.

[0144] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, and the computer system corrects the measured flame height as a function of the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value.

[0145] In the test apparatus of paragraph A, the means for taking a series of digital images of the flame may comprise a digital camera. Here, an apparatus for determining smoke point that complies with the specifications of the ASTM D1322-19 standard comprises a candle for holding a wick, a scale for measuring flame height, a gallery configured to take digital images of the flame and the scale, and a candle movement system for adjusting the height of the flame from the wick of the candle. Here, the normalized pressure value is a value between 800 and 1100 hPa, preferably 1013 hPa.

[0146] In the test apparatus of paragraph A, the ambient temperature sensor may be part of the ambient relative humidity sensor or may be separate from the ambient relative humidity sensor, and the computer system corrects the measured flame height based on the ambient pressure measured by the integrated ambient pressure sensor as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized previous ambient pressure recorded during calibration.

[0147] In the test apparatus of paragraph A, the ambient relative humidity sensor may also be configured to include a temperature sensor for measuring temperature.

[0148] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, the computer system corrects the measured flame height as a function of the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value, and further comprises a housing having an air intake and an exhaust, and the ambient relative humidity sensor is located adjacent to the air intake.

[0149] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, the computer system corrects the measured flame height as a function of the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value, and further comprises a housing having an air inlet and an air outlet, the ambient relative humidity sensor being located proximate to the air inlet, and the ambient relative humidity sensor being located on a chassis of the housing.

[0150] In the test apparatus of paragraph A, the ambient temperature sensor may be part of or separate from the ambient relative humidity sensor, and the computer system corrects the measured flame height as a function of the difference between the current ambient pressure measured by the ambient pressure sensor during the test and the normalized pressure value, and further comprises a housing having an air inlet and an air outlet, the ambient relative humidity sensor being located proximate to the air inlet, the ambient relative humidity sensor being located on a chassis of the housing, the housing having an air inlet and an air outlet, and the ambient temperature sensor being located proximate to the air inlet.

[0151] Paragraph B: The present invention also provides a method for determining the smoke point of a hydrocarbon fuel sample, the method comprising: measuring the ambient relative humidity using an ambient relative humidity sensor; measuring an ambient temperature using an ambient temperature sensor; and testing the fuel sample, the testing step comprising: - identifying a particular appearance of the flame among different appearances of the flame depending on the position of the burner within the lamp; reading the flame height on a scale; using a means for taking and storing digital images to take and store a series of digital images of the flame spaced sufficiently closely together to enable detection of changes in the shape of the flame by analyzing the digital images; measuring the height of the flame at the moment of change in flame shape, which height is taken as the measured smoke point of the hydrocarbon under test; inputting the measured flame height, the measured ambient relative humidity, and the measured ambient temperature into a computer system connected to the means for acquiring and storing digital images, the ambient relative humidity sensor, and the ambient temperature sensor; wherein the computer system is connected to a means for taking a series of digital images of the flame, connected to a humidity sensor, and connected to a temperature sensor, the computer system analyzes the digital images taken by the means for taking a series of digital images to measure the flame height, calculates the absolute humidity using a combination of the temperature measured by the ambient temperature sensor and the relative humidity measured by the relative humidity sensor during the test, and corrects the measured flame height as a function of the difference between the calculated absolute humidity and a normalized absolute humidity value to calculate a corrected smoke point; and reporting the corrected smoke point.

[0152] The method of paragraph B may include any of the following modifications:

[0153] The method of paragraph B is capable of determining a smoke point that conforms to the specifications of the ASTM D1322-19 standard.

[0154] The method of paragraph B may further comprise measuring the ambient pressure using an ambient pressure sensor connected to a computer system, wherein the computer system corrects the measured flash point value of the hydrocarbon based on the ambient pressure measured by the pressure ambient sensor as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized ambient pressure value.

[0155] In the method of paragraph B, the step of automatically correcting the measured smoke point may include correcting the calibration value while the test device is being calibrated as a function of the difference between the current atmospheric pressure measured by the integral pressure sensor and a normalized standard value, preferably a normalized standard value for pressure of 800 to 1100 hPa, most preferably 1013 hPa.

[0156] In the method of paragraph B, the means for capturing and storing digital images can comprise a digital camera, and wherein automatically correcting the measured smoke point can comprise normalizing real-time flash point measurements made by the digital camera to standard pressure.

[0157] In the method of paragraph B, the means for capturing and storing digital images can comprise a digital camera, and wherein automatically correcting the measured smoke point can comprise normalizing real-time flash point measurements made by the digital camera to standard pressure, wherein the normalized standard value of pressure is 101.3 kPa.

[0158] The method of paragraph B may further include an integral ambient pressure sensor connected to a computer system, the computer system correcting the measured flame height based on the ambient pressure measured by the integral ambient pressure sensor as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and a previous ambient pressure recorded during calibration.

[0159] In the method of paragraph B, the image capture interval may be between 0.1 seconds and 2.0 seconds.

[0160] In the method of paragraph B, the image capture interval may be between 0.5 seconds and 1 second.

[0161] In the method of paragraph B, detection of changes in flame shape can be achieved by measuring abrupt changes in the rate of decrease of the Feret diameter of an image of the flame.

[0162] In the method of paragraph B, detecting a change in the shape of the flame can be achieved by measuring an abrupt change in the rate of decrease of the Feret diameter of an image of the flame, wherein to detect an abrupt change in the rate of decrease of the Feret diameter, the Feret diameter is measured at an angle α of less than 45°.

[0163] In the method of paragraph B, detection of changes in flame shape can be achieved by measuring abrupt changes in the rate of decrease of the Feret diameter of the flame image, where the flame height is equal to the Feret diameter for α=0° of the flame image.

[0164] In the method of paragraph B, detecting a change in flame shape can be achieved by measuring an abrupt change in the rate of decrease of Feret diameter in an image of the flame, wherein the digital image corresponding to the abrupt change in the rate of decrease of Feret diameter is subjected to thresholding (also known as binarization), the thresholding comprising setting all pixels having a gray level below the identified threshold to zero and all pixels having a value above the threshold to one, using a threshold identified using one or more standard fuel mixtures (toluene / 2,2,4-trimethylpentane) with known smoke points (ASTM D1322-19). The threshold, which provides an absolute flame height that results in a measured smoke point for the fuel under test, is identified using one or more standard fuel mixtures (toluene / 2,2,4-trimethylolpropane) that have an ASTM D1322-19 smoke point.

[0165] In the method of paragraph B, the means for capturing and storing digital images may comprise a charge-coupled device (CCD) digital camera, a complementary metal-oxide semiconductor (CMOS) image sensor, or other image sensor, preferably covering wavelengths ranging from ultraviolet to infrared.

[0166] In the method of paragraph B, the means for capturing and storing digital images may comprise a charge-coupled device (CCD) digital camera, a complementary metal-oxide semiconductor (CMOS) image sensor, or other image sensor, preferably covering wavelengths ranging from ultraviolet to infrared, wherein an anti-infrared filter may be disposed between the frame and the means for capturing and storing digital images.

[0167] In the method of paragraph B, the means for capturing and storing digital images may comprise a charge-coupled device (CCD) digital camera, a complementary metal-oxide semiconductor (CMOS) image sensor, or other image sensor, preferably covering wavelengths ranging from ultraviolet to infrared, wherein the means for capturing and storing digital images is capable of storing digital images with at least 256 gray levels.

[0168] In the method of paragraph B, the image capture interval can be between 0.5 seconds and 1 second, and the means for capturing and storing digital images can be positioned at a distance of about 10 cm to 15 cm from the lamp.

[0169] In the method of paragraph B, the image capture interval can be 0.5 seconds to 1 second, the means for capturing and storing digital images can be positioned at a distance of about 10 cm to 15 cm from the lamp, and the means for capturing and storing digital images is configured so that the stored digital image includes images of all scales on the device for identifying the smoke point.

[0170] In the method of paragraph B, the number of digital images in each series may be at least equal to ten.

[0171] In the method of paragraph B, the method may use any of the test equipment of paragraph A or any of the paragraphs with modifications of paragraph A.

[0172] Paragraph C: The present invention also provides a test apparatus for determining the smoke point of a hydrocarbon, the test apparatus comprising: An apparatus for determining smoke point in accordance with the specifications of the ASTM D1322-19 standard; means for capturing a series of digital images of the flame; an ambient pressure sensor for measuring ambient pressure; a computer system connected to the means for taking a series of digital images of the flame and connected to the ambient pressure sensor, the computer system being programmed to analyze the digital images taken by the means for taking the series of digital images to measure the flame height and to use the pressure measured by the pressure sensor to correct the measured flash point value of the hydrocarbon based on the ambient pressure measured by the ambient pressure sensor as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and a normalized ambient pressure value.

[0173] In the test apparatus of paragraph C, the means for taking a series of digital images of the flame may comprise a digital camera. Here, an apparatus for determining smoke point that complies with the specifications of the ASTM D1322-19 standard comprises a candle for holding a wick, a scale for measuring flame height, a gallery configured to take digital images of the flame and the scale, and a candle movement system for adjusting the height of the flame from the wick of the candle.

[0174] The test equipment of paragraph C: Power supply and; a housing; and the housing comprising: means for capturing a series of digital images of the flame, said means comprising a digital camera; an ambient pressure sensor; The system may further comprise a computer system connected to the means for capturing a series of digital images, the computer system comprising an electronic device including a microprocessor.

[0175] In the test apparatus of paragraph C, the test apparatus may include ventilation means, an intake port for introducing airflow into the test apparatus housing, and an exhaust port for expelling the airflow heated within the test apparatus housing out of the housing.

[0176] Paragraph D The present invention may also provide a method for determining the smoke point of a hydrocarbon fuel sample, the method comprising: measuring the ambient pressure using an ambient pressure sensor; and testing the fuel sample, the testing step comprising: - identifying a particular appearance of the flame among different appearances of the flame depending on the position of the burner within the lamp; reading the flame height on a scale; using a means for taking and storing digital images to take and store a series of digital images of the flame spaced sufficiently closely together to enable detection of changes in the shape of the flame by analyzing the digital images; measuring the height of the flame at the moment of change in flame shape, said height being taken as the measured smoke point of the hydrocarbon under test; inputting the measured flame height and the measured ambient pressure into a computer system connected to a means for acquiring and storing digital images and an ambient pressure and temperature sensor; wherein the computer system automatically uses the ambient pressure measured by the ambient pressure sensor to correct the measured flame height values ​​of the hydrocarbons as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and the normalized ambient pressure to calculate a corrected smoke point; and reporting the corrected smoke point.

[0177] The method of paragraph D allows for the determination of smoke points that comply with the specifications of the ASTM D1322-19 standard.

[0178] In the method of paragraph D, the method may use any of the test equipment of paragraph C or any of the paragraphs with the modifications of paragraph C.

[0179] In the method of paragraph D, detection of changes in flame shape can be achieved by measuring abrupt changes in the rate of decrease of the Feret diameter of an image of the flame.

[0180] Although compositions and methods are described in terms of "comprising," "containing," or "including" various components or steps, compositions and methods can also "consist essentially of" or "consist of" various components and steps. All numerical values ​​and ranges disclosed above may vary slightly. Whenever a numerical range with a lower and upper limit is disclosed, any numerical value within that range and any included range is specifically disclosed. In particular, all ranges of values ​​disclosed herein (in the form "from about a to about b," or, equivalently, "from about a to b," or, equivalently, "from about a to b") should be understood to define all numerical values ​​and ranges within that broader range of values. Additionally, claim terms shall have their plain and ordinary meaning unless expressly and unambiguously defined otherwise by the patentee. Furthermore, the indefinite article "a" or "an," as used in the claims, is defined herein to mean one or more of the element it introduces. In the event of a conflict between the usage of a word or term in this specification and one or more patents or other documents that may be incorporated herein by reference, the consistent definition in this specification shall control.

[0181] The use of directional terms such as up, down, upper, lower, upward, downward, left, right, etc. are used in connection with the exemplary embodiments as they are shown in the figures, with upward or upward directions being directions toward the top of the corresponding figure, and downward or downward directions being directions toward the bottom of the corresponding figure.

[0182] As used herein, the phrase "at least one of" preceding a list of items, together with the term "and" or "or" separating any of the items, modifies the list as a whole and not each member (i.e., each item) of the list. The phrase "at least one of" allows for a meaning including at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" refers to A only, B only, or C only, any combination of A, B, and C, and / or at least one of each of A, B, and C, respectively.

[0183] Sample Calculation - Relative Humidity to Absolute Humidity Conversion Formula 1. Saturated vapor pressure of water The saturated vapor pressure of water between 16°C and 30°C can be estimated by the following formula:

[0184]

number

[0185]

number

[0186]

number

[0187]

number

[0188]

number

[0189]

number

[0190]

number

[0191]

number

Claims

1. 1. A test apparatus for determining the smoke point of a hydrocarbon, comprising: an apparatus for determining said smoke point conforming to the specifications of the ASTM D1322-19 standard; means for capturing a series of digital images of the flame; an ambient relative humidity sensor for measuring relative humidity; an ambient temperature sensor for measuring temperature; a computer system connected to the means for taking the series of digital images of the flame, connected to the humidity sensor, and connected to the ambient temperature sensor, the computer system being programmed to analyze digital images taken by the means for taking the series of digital images to measure flame height, calculate the absolute humidity using a combination of the temperature measured by the ambient temperature sensor and the relative humidity measured by the relative humidity sensor, and correct the measured flame height as a function of the difference between the calculated absolute humidity and a normalized absolute humidity value.

2. 10. The testing apparatus of claim 1, further comprising an ambient pressure sensor connected to the computer system, wherein the computer system corrects the measured flash point value of the hydrocarbon based on the ambient pressure measured by the integrated ambient pressure sensor as a function of the difference between a current ambient pressure measured by the pressure sensor during testing and a normalized pressure value.

3. 10. The test device of claim 1, wherein an ambient temperature sensor is part of the ambient relative humidity sensor or is separate from the ambient relative humidity sensor.

4. The test device of claim 1, wherein the normalized humidity value is a value in the range of 0 gr / m 3 to 40 gr / m 3 .

5. A testing device as described in claim 3, further comprising a housing having an intake port and an exhaust port, wherein the ambient relative humidity sensor is located in close proximity to the intake port.

6. A testing device as described in Claim 5, wherein the housing has an air intake and an exhaust port, and the ambient humidity sensor is located close to the air intake.

7. A method for determining the smoke point of a hydrocarbon fuel sample, comprising: measuring the ambient relative humidity using an ambient relative humidity sensor; measuring an ambient temperature using an ambient temperature sensor; and testing the fuel sample, the testing step comprising: - identifying a particular appearance of the flame among different appearances of the flame depending on the position of the burner within the lamp; reading the flame height on a scale; using a means for taking and storing digital images to take and store a series of digital images of the flame spaced sufficiently closely together to allow detection of changes in the shape of the flame by analyzing the digital images; measuring the height of the flame at the instant of said change in flame shape, said height being taken as the measured smoke point of the hydrocarbon under test; inputting the measured flame height, the measured ambient relative humidity, and the measured ambient temperature into a computer system connected to the means for acquiring and storing digital images, the ambient relative humidity sensor, and the ambient temperature sensor; the computer system is connected to the means for taking a series of digital images of the flame, connected to the humidity sensor, and connected to the temperature sensor, the computer system analyzing the digital images taken by the means for taking a series of digital images to measure a flame height, calculating the absolute humidity using a combination of the temperature measured by the ambient temperature sensor and the relative humidity measured by the relative humidity sensor, correcting the measured flame height as a function of the difference between the calculated absolute humidity and a normalized absolute humidity value to calculate a corrected smoke point, and reporting the humidity corrected smoke point.

8. The method of claim 7, further comprising the step of measuring ambient pressure using an ambient pressure sensor connected to the computer system, wherein the computer system corrects the measured flash point value of the hydrocarbon based on the ambient pressure measured by the ambient pressure sensor as a function of the difference between the current ambient pressure measured by the pressure sensor during the test and a normalized standard pressure value.

9. The method described in claim 7, wherein the step of automatically correcting the measured smoke point includes a step of correcting a calibration value during calibration of the test device as a function of the difference between the current atmospheric pressure measured by the integrated pressure sensor and a normalized standard value.

10. The method of claim 7, further comprising an integrated ambient pressure sensor connected to the computer system, wherein the computer system corrects the measured flame height as a function of the difference between the current ambient pressure measured by the ambient pressure sensor during the test and a normalized pressure value.

Images