A method for compensating for temperature in the field for foam expansion and 25% drainage time

Abstract

The application discloses a foam multiple and 25% liquid separation time on-site detection temperature compensation method, S1: different kinds of foam extinguishing agents are sampled, and each foam extinguishing agent is configured into several foam mixtures with different temperatures according to a mixing ratio; S2: the foam mixtures with different temperatures in step S1 generate foam respectively, and the foam multiple, 25% liquid separation time and generated foam temperature are measured; S3: a first fitting equation of the generated foam temperature and the foam multiple ratio of different kinds of foam extinguishing agents is established respectively, and a second fitting equation of the generated foam temperature and the 25% liquid separation time ratio of different kinds of foam extinguishing agents is established; the on-site detected foam multiple and 25% liquid separation time are corrected through the first fitting equation and the second fitting equation respectively. The application can reduce the influence of the on-site environment temperature, obtain the foam multiple and 25% liquid separation time standard data of the foam temperature of 20 DEG C on site, and improve the accuracy and authority of the detection result.

Description

Technical Field

[0001] This invention belongs to the field of field performance testing technology for foam fire extinguishing agents, and in particular relates to a temperature compensation method for field testing of foam expansion ratio and 25% liquid separation time. Background Technology

[0002] In the performance of low-expansion foam extinguishing agents, foam expansion ratio and 25% eluent time are two crucial foam properties. Foam expansion ratio is a key indicator of the foaming ability of a foam extinguishing agent; failure to foam or an excessively low foam expansion ratio will prevent the foam from remaining on the oil surface for fire extinguishing. The 25% eluent time is a crucial indicator of the stability of a foam extinguishing agent; an insufficient 25% eluent time will cause the sprayed foam to quickly eluent and sink below the oil layer (oil generally has a lower density than water and floats on the surface), failing to remain on the oil surface for an extended period to provide coverage. When foam extinguishing agents fail due to improper storage or substandard quality, this is often manifested as insufficient foam expansion ratio and an excessively short 25% eluent time. Current on-site testing devices for low-expansion foam performance primarily test these two indicators: foam expansion ratio and 25% eluent time.

[0003] Temperature changes have a significant impact on the foam ratio and 25% separation time tests. When the temperature rises, the foam ratio increases and the 25% separation time shortens. Within the temperature range of 0~50℃, according to the field test results, the change rate of the 25% separation time differs by nearly 100%. The GB 15308 standard for foam extinguishing agents specifies test methods for foam expansion and 25% separation time. These tests must be conducted at an ambient temperature of (15-25)℃, while simultaneously controlling the temperature of the foam solution to ensure the generated foam temperature remains within the range of (15-20)℃. To achieve this, the test must be conducted indoors where this ambient temperature can be maintained. Ice or hot water must be added during foam solution preparation for temperature adjustment. However, on-site testing of foam extinguishing agents often takes place outdoors, making it difficult to achieve these ambient temperatures in summer and winter. Furthermore, it is sometimes difficult to prepare ice and hot water, thus failing to fully meet the test conditions. Current on-site testing devices for low-expansion foam performance lack temperature compensation functionality, resulting in significant errors in on-site test data. This makes direct comparison with test reports impossible, causing inconvenience for on-site comparison and judgment. Summary of the Invention

[0004] In view of this, in order to solve the problem of temperature error in existing foam performance field test data, this invention provides a temperature compensation method for field testing of foam expansion and 25% exudation time. This method can compensate for the temperature of foam expansion and 25% exudation time test data during field measurement, thereby improving the accuracy of field testing of foam expansion and 25% exudation time of low-expansion foam extinguishing agents and reducing test errors caused by temperature.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation includes the following steps:

[0007] S1: Samples of different types of foam extinguishing agents were taken, and each foam extinguishing agent was prepared into several foam mixtures at different temperatures according to its mixing ratio.

[0008] S2: In step S1, several foam mixtures at different temperatures generate foam, and the foam ratio, 25% separation time, and foam temperature are measured.

[0009] S3: Establish the first fitting equation for the ratio of foam temperature to foam expansion ratio for different types of foam extinguishing agents, and establish the second fitting equation for the ratio of foam temperature to 25% liquid outflow time for different types of foam extinguishing agents; correct the foam expansion ratio and 25% liquid outflow time detected on site using the first and second fitting equations respectively.

[0010] Furthermore, the different types of foam extinguishing agents in step S1 include one or more of protein foam extinguishing agents, fluoroprotein foam extinguishing agents, film-forming fluoroprotein foam extinguishing agents, aqueous film-forming foam extinguishing agents, alcohol-resistant foam extinguishing agents, and synthetic foam extinguishing agents.

[0011] Furthermore, in step S1, the number of foam mixtures at different temperatures is at least 10, and the temperature is 0~50℃;

[0012] Several foam mixtures at different temperatures were prepared by adding ice or hot water to each mixture.

[0013] Furthermore, in step S2, several foam mixtures at different temperatures generate foam in a standard foam generating system (a foam generating system that meets the requirements of GB 15308 "Foam Extinguishing Agents" standard).

[0014] Furthermore, in step S2, when measuring the foam ratio, 25% separation time, and foam temperature of foam mixtures at different temperatures, the baseline 25% separation time and baseline foam ratio are obtained when the foam temperature is measured to be 20°C.

[0015] Furthermore, the formula for calculating the foam expansion ratio in step S3, which is the ratio of the foam expansion ratio to the reference foam expansion ratio at different foam temperatures, is (Ⅰ).

[0016] A = P / P 20℃ (I);

[0017] A represents the foam ratio;

[0018] P represents the foaming factor;

[0019] P 20℃ This indicates the reference foam ratio at a foam temperature of 20℃.

[0020] In step S3, the formula for calculating the ratio of 25% separation time to the baseline 25% separation time at different foaming temperatures is (II).

[0021] B=T / T 20℃ (II);

[0022] B represents the 25% precipitation time ratio;

[0023] T represents the 25% precipitation time, measured in seconds.

[0024] T 20℃ The time for 25% separation of the foam at a temperature of 20°C is expressed in seconds.

[0025] Furthermore, in step S3, the least squares method is used to establish the first fitting equation for the ratio of foam temperature to foam ratio, and the least squares method is used to establish the second fitting equation for the ratio of generated foam temperature to 25% separation time.

[0026] The first fitting equation is: A = a1t 2 +b1t+c1;

[0027] A represents the foam ratio;

[0028] a1, b1, and c1 are constants;

[0029] The second fitting equation is: B = a²t 2 +b2t+c2;

[0030] B represents the 25% precipitation time ratio;

[0031] a2, b2, and c2 are constants.

[0032] Furthermore, the correction of the foam expansion ratio and 25% separation time detected on-site using the first and second fitting equations respectively includes the following steps:

[0033] A1: Determine the type of foam extinguishing agent measured on site, and select the corresponding first and second fitting equations according to the type of foam extinguishing agent;

[0034] A2: Prepare the foam extinguishing agent to be tested into a foam mixture according to the mixing ratio. The foam mixture produces foam, and the foam expansion ratio, 25% separation time, and foam temperature are measured.

[0035] A3: The measured foam expansion ratio, 25% eluent time, and generated foam temperature obtained in step A2 are corrected using the first and second fitting equations obtained in step A1 to obtain the corrected foam expansion ratio and corrected 25% eluent time. The quality of the foam extinguishing agent is then determined based on the corrected foam expansion ratio and corrected 25% eluent time.

[0036] Furthermore, step A2 also includes preparing a foam mixture by mixing the same type of foam extinguishing agent according to the mixing ratio, using on-site water source, without temperature control, and generating foam in a standard foam generating system (a foam generating system that meets the requirements of GB 15308 "Foam Extinguishing Agents" standard);

[0037] The formula for calculating the corrected foam ratio in step A3 is (Ⅲ);

[0038] P 修= P 测 / f1(t 测 );

[0039] P 修 This is the corrected foam ratio;

[0040] P 测 The foam expansion ratio is measured in step A2;

[0041] f1(t) 测 To set the foam temperature t 测 The foam ratio obtained after substituting it into the first fitting equation;

[0042] The formula for calculating the corrected 25% precipitation time in step A3 is (Ⅳ);

[0043] T 修= T 测 / f2(t) 测 );

[0044] T 修 The corrected 25% precipitation time is expressed in seconds.

[0045] T 测 The measurement time for 25% precipitation in step S3 is expressed in seconds.

[0046] f2(t) 测 To set the foam temperature t 测 The 25% precipitation time was obtained after substituting it into the second fitting equation.

[0047] Further, in step A3, the quality of the foam extinguishing agent is judged based on the corrected foam ratio and the corrected 25% separation time. This includes ensuring that the difference between the corrected foam ratio and the characteristic foam ratio of the foam extinguishing agent is not greater than 1 or not greater than 20% of the characteristic foam ratio of the foam extinguishing agent, and that the corrected 25% separation time is not greater than 20% of the characteristic 25% separation time of the foam extinguishing agent. If these conditions are met, the product is considered qualified; otherwise, it is considered unqualified.

[0048] Compared with existing technologies, the temperature compensation method for on-site detection of foam expansion ratio and 25% eluent separation time described in this invention has the following advantages:

[0049] This invention provides a temperature compensation method for on-site testing of foam expansion ratio and 25% exudation time. First and second fitting equations are obtained through pre-calibration. When using a low-expansion foam performance on-site testing device to test foam expansion ratio and 25% exudation time, temperature compensation is applied to the test data, resulting in foam expansion ratio and 25% exudation time data corrected to a foam temperature of 20°C. This reduces the influence of ambient temperature, improves the accuracy of test results, and allows for comparison of on-site test data with test reports. This facilitates on-site quality assessment of foam extinguishing agents and provides a technical means for on-site acceptance and annual inspection of foam extinguishing agents. Attached Figure Description

[0050] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0051] Figure 1 This is a flowchart of a method for on-site detection of foam expansion and temperature compensation for 25% separation time as described in Embodiment 1 of the present invention. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0053] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] Example 1

[0055] A temperature compensation method for on-site detection of foam expansion ratio and 25% separation time, including a calibration stage and a measurement stage.

[0056] The steps in the calibration phase are as follows:

[0057] S1: Select different types of low-expansion foam extinguishing agents (such as aqueous film-forming agents, solvent-resistant aqueous film-forming agents, protein, fluoroprotein, synthetic foam extinguishing agents, etc.), and prepare N foam mixtures at different temperatures by adding ice or hot water according to their mixing ratio requirements.

[0058] S2: Then, foam mixtures at different temperatures are used sequentially to generate foam in a standard foam generation system. Simultaneously, the foam expansion ratio P and the 25% outflow time T are measured, along with the temperature of the generated foam. Data on the foam expansion ratio P and the 25% outflow time T at N different foam temperatures for the corresponding foam extinguishing agent type are obtained (including the foam expansion ratio P at a foam temperature of 20℃). 20℃ And 25% precipitation time data T 20℃ (as benchmark data).

[0059] S3: Calculate the ratios of foam expansion and 25% separation time to the baseline data at different foaming temperatures:

[0060] A = P / P 20℃

[0061] B=T / T 20℃

[0062] Where A represents the foam ratio, B represents the 25% separation time ratio, P represents the foam ratio, and T represents the 25% separation time. 20℃ T represents the foam ratio at a foaming temperature of 20℃. 20℃ This indicates the 25% separation time when the foam temperature is 20℃.

[0063] S4: The least squares method was used to fit the foam expansion ratio A and the 25% outflow time ratio B of different types of foam extinguishing agents at different foam temperatures. First fitting equations for the foam temperature versus foam expansion ratio and second fitting equations for the foam temperature versus 25% outflow time ratio were established for different types of foam extinguishing agents. The first fitting equation is A = f1(t), and the second fitting equation is B = f2(t), where t represents the foam temperature.

[0064] The steps in the measurement phase are as follows:

[0065] S5: First, determine the type of foam extinguishing agent being measured on site, and then select the first and second fitting equations corresponding to the foam type.

[0066] S6: Prepare the tested foam extinguishing agent into a foam mixture according to the required mixing ratio. Use on-site water as the water source; temperature control is not required. Generate foam in a standard foam generation system and measure the foam expansion ratio P. 测 and 25% precipitation time T 测 At the same time, the temperature t of the generated foam was measured. 测 .

[0067] S7: Based on foam temperature t 测 The first and second fitting equations are used to calculate the foam ratio P, corrected for a foam temperature of 20℃. 修 and 25% precipitation time T 修。

[0068] P 修= P 测 / f1(t 测 ), T 修= T 测 / f2(t) 测 )

[0069] Prepare N foam mixtures at different temperatures, with the temperature range being 0~50℃, and the number N is not less than 10.

[0070] The least squares method was used to fit the foam expansion ratio A and the 25% liquid separation time ratio B of different types of foam extinguishing agents at different foam temperatures. The expressions for the first fitting equation A=f1(t) and the second fitting equation B=f2(t) are as follows:

[0071] A=a1t 2 +b1t+c1,B=a2t 2 +b2t+c2, where a1, b1, c1, a2, b2, and c2 are constants.

[0072] Example 2

[0073] A temperature compensation method for on-site detection of foam expansion ratio and 25% separation time, including a calibration stage and a measurement stage.

[0074] The steps in the calibration phase are as follows:

[0075] S1: Select 6% aqueous film-forming foam extinguishing agent, and prepare 14 foam mixtures at different temperatures by adding ice or hot water according to its 6% mixing ratio requirement.

[0076] S2: Then, foam mixtures at different temperatures are used sequentially to generate foam in a standard foam generation system. Simultaneously, the foam expansion ratio P and the 25% outflow time T are measured, along with the temperature of the generated foam. Data on the foam expansion ratio P and the 25% outflow time T at N different foam temperatures for the corresponding foam extinguishing agent type are obtained (including the foam expansion ratio P at a foam temperature of 20℃). 20℃ And 25% precipitation time data T 20℃ (as benchmark data).

[0077] Table 1. Foam ratio and 25% separation time at different foaming temperatures

[0078] Serial Number Foam solution temperature (°C) multiple 25% precipitation time (s) Foam temperature (°C) 1 2 7.16 175 8 2 5 7.29 169 12 3 8 7.59 175 13 4 10 7.35 172 14.5 5 13 7.62 165 17 6 15 7.16 170 18 7 16 7.43 168 19 8 18 7.61 160 20 9 20 7.63 163 21.5 10 21 7.98 156 23 11 24 7.92 150 25 12 30 8.24 140 28 13 40 8.86 130 35 14 48 9.23 123 40

[0079] S3: Calculate the ratios of foam expansion and 25% separation time to the baseline data at different foaming temperatures:

[0080] A = P / P 20℃

[0081] B=T / T 20℃

[0082] Where A represents the foam ratio, B represents the 25% separation time ratio, P represents the foam ratio, and T represents the 25% separation time. 20℃ T represents the foam ratio at a foaming temperature of 20℃. 20℃ This indicates the 25% separation time when the foam temperature is 20℃.

[0083] Table 2. Ratios of foam expansion and 25% separation time to baseline data at different foaming temperatures.

[0084] Serial Number Foam temperature (°C) A B 1 8 0.9409 1.0938 2 12 0.9580 1.0563 3 13 0.9974 1.0938 4 14.5 0.9658 1.0750 5 17 1.0013 1.0313 6 18 0.9409 1.0625 7 19 0.9763 1.0500 8 20 1.0000 1.0000 9 21.5 1.0026 1.0188 10 23 1.0486 0.9750 11 25 1.0407 0.9375 12 28 1.0828 0.8750 13 35 1.1643 0.8125 14 40 1.2129 0.7688

[0085] S4: Based on the data in Table 2, the least squares method was used to perform polynomial fitting on the foam expansion ratio A and the 25% liquid separation time ratio B at 14 different foam temperatures for different types of foam extinguishing agents. The expressions for the first fitting equation A=f1(t) and the second fitting equation B=f2(t) are as follows:

[0086] A=a1t 2 +b1t+c1

[0087] B=a2t 2 +b2t+c2

[0088] Where t represents the foam temperature.

[0089] The calculated value is a1 = 2.01016 × 10 -4 b1 = -9.88172 × 10 -4 , c1=0.94132, a2=-1.46871×10 -4 b2 = -4.35 × 10 -3 Given c2 = 1.15602, the first fitting equation for the temperature-to-foam ratio of 6% aqueous film-forming foam extinguishing agent is A = 2.01016 × 10⁻⁶. -4 t 2 -9.88172×10 -4 The second fitting equation for the ratio of temperature to 25% effervescence time of 6% aqueous film-forming foam extinguishing agent is B = -1.46871 × 10⁻⁶. -4 t 2 -4.35×10 -3t+1.15602.

[0090] The steps in the measurement phase are as follows:

[0091] S5: First, determine that the type of foam extinguishing agent measured on site is 6% aqueous film-forming foam extinguishing agent, and select the first and second fitting equations obtained from the above calculation.

[0092] S6: Prepare the tested foam extinguishing agent into a foam mixture according to the required mixing ratio. Use on-site water as the water source; temperature control is not required. Generate foam in a standard foam generation system and measure the foam expansion ratio P. 测 =8.48 and 25% precipitation time T 测 At the same time, the temperature t of the generated foam was measured at 142s. 测 =30℃.

[0093] S7: Based on foam temperature t 测 =30℃, calculate the foam ratio P corrected to a foam temperature of 20℃ based on the first and second fitting equations respectively. 修 and 25% precipitation time T 修。

[0094] P 修= P 测 / f1(t 测 =7.76, T 修= T 测 / f2(t) 测 =159s.

[0095] According to the product's test report, its published characteristic values ​​are a foam expansion ratio of 8 and a 25% eluent extraction time of 180 seconds. However, under standard experimental conditions, the foam expansion ratio was measured at 7.8 and the 25% eluent extraction time at 168 seconds. According to GB 15308 "Foam Extinguishing Agents" standard, the foam expansion ratio should deviate from the characteristic value by no more than 1.0 or 20%, and the 25% eluent extraction time should deviate by no more than 20%. If the on-site measurement data (foam expansion ratio P) is used directly... 测 =8.48 and 25% precipitation time T 测 If compared to 142s, the deviation of the 25% precipitation time from the characteristic value is greater than 20%, and the result is deemed unqualified. The foam ratio P after temperature compensation... 修 and 25% precipitation time T 修 The data is very close to the data in the test report. By comparing the corrected data with the characteristic value, the standard requirements are met and the result is deemed qualified. This proves that the present invention reduces the influence of the ambient temperature on site, improves the accuracy of the test results, and enables the on-site test data to be compared with the test report, facilitating the on-site quality judgment of foam fire extinguishing agents.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation, characterized in that: Includes the following steps: S1: Samples of different types of foam extinguishing agents were taken, and each foam extinguishing agent was prepared into several foam mixtures at different temperatures according to its mixing ratio. S2: In step S1, several foam mixtures at different temperatures generate foam, and the foam ratio, 25% separation time, and foam temperature are measured. S3: Establish the first fitting equation for the ratio of foam temperature to foam expansion ratio for different types of foam extinguishing agents, and establish the second fitting equation for the ratio of foam temperature to 25% liquid outflow time for different types of foam extinguishing agents; correct the foam expansion ratio and 25% liquid outflow time detected on site using the first and second fitting equations respectively. The formula for calculating the foam expansion ratio in step S3, which is the ratio of the foam expansion ratio to the reference foam expansion ratio at different foam temperatures, is (Ⅰ). A = P / P 20℃ (I); A represents the foam ratio; P represents the foaming factor; P 20℃ Reference foam volume at 20°C; In step S3, the formula for calculating the ratio of 25% separation time to the baseline 25% separation time at different foaming temperatures is (II). B = T / T 20℃ (II); B represents the 25% precipitation time ratio; T represents the 25% precipitation time, measured in seconds. T 20℃ represents the reference 25% drainage time of the foam at a temperature of 20°C, in s; In step S3, the least squares method is used to establish the first fitting equation for the ratio of foam temperature to foam ratio, and the least squares method is used to establish the second fitting equation for the ratio of generated foam temperature to 25% separation time. The first fitting equation is: A = a1t 2 + b1t + c1; A represents the foam ratio; a1, b1, and c1 are constants; The second fitting equation is: B = a2t 2 + b2t + c2; B represents the 25% precipitation time ratio; a2, b2, and c2 are constants; The correction of the foam expansion ratio and 25% separation time detected on-site using the first and second fitting equations includes the following steps: A1: Determine the type of foam extinguishing agent measured on site, and select the corresponding first and second fitting equations according to the type of foam extinguishing agent; A2: Prepare the foam extinguishing agent to be tested into a foam mixture according to the mixing ratio. The foam mixture produces foam, and the foam expansion ratio, 25% separation time, and foam temperature are measured. A3: The measured foam expansion ratio, 25% liquid outflow time, and generated foam temperature obtained in step A2 are corrected using the first fitting equation and the second fitting equation obtained in step A1 to obtain the corrected foam expansion ratio and the corrected 25% liquid outflow time. The quality of the foam extinguishing agent is judged based on the corrected foam expansion ratio and the corrected 25% liquid outflow time. Step A2 also includes preparing a foam mixture by mixing the same type of foam extinguishing agent according to the mixing ratio. The water used is the on-site water source, and there is no need to control the temperature. Foam is generated in a standard foam generation system. The formula for calculating the corrected foam ratio in step A3 is (Ⅲ); P 修= P 测 / f1(t 测 ). P 修 This is the corrected foam ratio; P 测 The foam expansion ratio is measured in step A2; f1(t) 测 To set the foam temperature t 测 The foam ratio obtained after substituting it into the first fitting equation; The formula for calculating the corrected 25% precipitation time in step A3 is (Ⅳ); T 修= T 测 / f2(t 测 ); T 修 The corrected 25% precipitation time is expressed in seconds. T 测 The measurement time for 25% precipitation in step S3 is expressed in seconds. f2(t) 测 To set the foam temperature t 测 The 25% precipitation time was obtained after substituting it into the second fitting equation.

2. The method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation according to claim 1, characterized in that: The different types of foam extinguishing agents in step S1 include one or more of the following: protein foam extinguishing agents, fluoroprotein foam extinguishing agents, film-forming fluoroprotein foam extinguishing agents, aqueous film-forming foam extinguishing agents, alcohol-resistant foam extinguishing agents, and synthetic foam extinguishing agents.

3. The method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation according to claim 1, characterized in that: In step S1, the number of foam mixtures at different temperatures is at least 10, and the temperature is 0~50℃; Several foam mixtures at different temperatures were prepared by adding ice or hot water to each mixture.

4. The method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation according to claim 1, characterized in that: In step S2, several foam mixtures at different temperatures generate foam in a standard foam generation system.

5. The method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation according to claim 1, characterized in that: In step S2, when measuring the foam ratio, 25% separation time, and foam temperature of foam mixtures at different temperatures, the baseline 25% separation time and baseline foam ratio are obtained when the foam temperature is measured to be 20°C.

6. The method for on-site detection of foam expansion ratio and 25% separation time with temperature compensation according to claim 1, characterized in that: In step A3, the quality of the foam extinguishing agent is judged based on the corrected foam ratio and the corrected 25% separation time. This includes ensuring that the difference between the corrected foam ratio and the characteristic foam ratio of the foam extinguishing agent is not greater than 1 or not greater than 20% of the characteristic foam ratio of the foam extinguishing agent, and that the corrected 25% separation time is not greater than 20% of the characteristic 25% separation time of the foam extinguishing agent. Otherwise, it is considered unqualified.

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