Device and method for measuring normal-temperature air permeability of casting coating

Abstract

The invention relates to the technical field of casting process material performance detection, in particular to a device and a method for measuring normal-temperature air permeability of a casting coating. The device comprises a tester main body, a vacuum pump and a central controller, and is characterized in that a multi-channel parallel test expansion module and an intelligent environment compensation and self-calibration unit are additionally arranged. The multi-channel module adopts a one-pump double-cavity structure, and can synchronously or sequentially test at least two samples and calculate the consistency of the air permeability of the samples. The intelligent unit collects environmental data in real time through a temperature and humidity sensor, corrects the permeability coefficient based on a preset compensation model, and can automatically execute system calibration by using a built-in standard calibration sheet. According to the method, efficient and accurate batch testing is realized, and the testing efficiency and the comparability and long-term stability of data in different environments are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of casting process material performance testing technology, and in particular to an apparatus and method for measuring the room temperature permeability of casting coatings. Background Technology

[0002] The permeability of casting coatings is one of the key performance indicators affecting the quality of castings. Currently, the industry commonly uses a room-temperature permeability tester based on the negative pressure method for testing. However, existing testing techniques have significant shortcomings: First, the testing efficiency is low, typically only a single sample can be tested at a time, making it difficult to meet the industrial needs of batch quality inspection or rapid comparison of multiple formulations; second, environmental interference is significant, as changes in ambient temperature and humidity affect the internal microporous structure and gas permeation behavior of the coating sample, resulting in large fluctuations and poor comparability of test data obtained at different times and locations; finally, the system lacks long-term stability, as the sensor and gas path system drift over time, and existing devices lack a convenient and effective online self-calibration mechanism, affecting the long-term accuracy of test results.

[0003] In summary, current technologies lack an integrated and intelligent permeability measurement solution capable of simultaneously performing parallel testing of multiple samples, real-time compensation of environmental parameters, and periodic self-calibration of the system. Therefore, developing a device and method with these functions is of great significance for improving the production quality control level and R&D efficiency of casting coatings. Summary of the Invention The purpose of this invention is to provide an apparatus and method for measuring the air permeability of casting coatings at room temperature, which can solve the above-mentioned technical problems.

[0004] This invention provides an apparatus for measuring the air permeability of casting coatings at room temperature, comprising an intelligent air permeability measuring instrument body, a vacuum pump connected to the measuring instrument body, and a central controller, and further comprising: A multi-channel parallel testing expansion module is connected to the main body of the measuring instrument. The multi-channel parallel testing expansion module includes at least two independent testing chambers. Each testing chamber is equipped with a pressure sensor, an independent gas path control solenoid valve, and a sample clamping interface. The testing chamber is connected to the main body of the measuring instrument through a gas collection pipe, and then the main body of the measuring instrument is connected to a vacuum pump. The intelligent environmental compensation and self-calibration unit is integrated into the main body of the measuring instrument, including a temperature and humidity sensor for collecting the temperature and humidity of the test environment, a built-in standard calibration plate, and an embedded microprocessor storing environmental compensation algorithms and self-calibration programs. The central controller is used to synchronously control the testing process of each test chamber and to call the environmental compensation algorithm to process the test data. The aforementioned intelligent air permeability measuring instrument is a conventional existing device.

[0005] Preferably, the multi-channel parallel test expansion module is a detachable accessory.

[0006] Preferably, the multi-channel parallel test expansion module adopts a single-pump dual-chamber configuration, and each chamber is independently evacuated and timed by switching through a solenoid valve.

[0007] Preferably, the built-in standard calibration strip has a known and stable air permeability value for periodic automatic system calibration.

[0008] Preferably, the device further includes a sample preparation module, which includes a constant temperature oven and a sample mold for preparing standard coating sample pieces.

[0009] Preferably, the central controller is further configured with a data fusion module for calculating the average value and consistency deviation index of multi-channel test results.

[0010] The present invention also provides a method for determining the air permeability of casting coatings at room temperature, using the above-mentioned apparatus, and comprising the following steps: S1: Prepare at least two coating sample pieces from the same batch and load them into a multi-channel test chamber; S2: Real-time acquisition of ambient temperature and humidity data; S3: Start multi-channel parallel testing, simultaneously evacuate each chamber and record the pressure change time; S4: Calculate the air permeability coefficient of each sample based on the pressure change time; S5: Compensation and correction of air permeability coefficient based on environmental parameters; S6: Output the test results.

[0011] Preferably, the consistency evaluation of the air permeability coefficient is calculated using the following formula:

[0012] Wherein, K1 and K2 are the air permeability coefficients measured in each channel. If ΔK > 5%, the system will indicate that the sample is abnormal.

[0013] Preferably, the environmental compensation adopts the following formula:

[0014] Where T0=20℃ and RH0=50% are standard environmental reference values, and α and β are material property-related compensation coefficients. α and β can be obtained through experimental fitting, table lookup, or material database.

[0015] The unit for α (temperature compensation coefficient) is usually °C. -1, represents the relative rate of change of the coating's air permeability coefficient (K) with temperature under a standard environment with constant humidity (RH0=50%). β (humidity compensation coefficient), usually expressed as 1 / %RH, represents the relative rate of change of the coating's air permeability coefficient (K) with relative humidity under a standard environment with constant temperature (T0=20℃).

[0016] Preferably, the test results include the compensated air permeability coefficient K of the two samples. 1补偿 K 2补偿 Average air permeability coefficient K avg And consistency deviation ΔK.

[0017] Preferably, the system also includes a self-calibration step: after a certain number of tests are performed periodically or cumulatively, the built-in standard calibration sheet is automatically used for testing. If the result deviation exceeds the set threshold, the sensor calibration coefficient is automatically updated.

[0018] Beneficial effects: This invention enables simultaneous testing of multiple samples through a multi-channel parallel testing expansion module, significantly improving testing efficiency and batch testing capabilities. Integrating an intelligent environmental compensation and self-calibration unit, it can collect temperature and humidity data in real time and automatically correct the data based on a built-in algorithm, effectively eliminating environmental interference and ensuring accurate and reliable results. The system has a periodic self-calibration function, which can autonomously correct sensor drift, ensuring long-term testing stability. Overall, this device achieves efficient, accurate, and stable integrated intelligent testing, greatly improving the consistency of casting coating quality control and R&D efficiency. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the device of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 1-Main body of intelligent air permeability tester, 2-Vacuum pump, 3-Central controller, 4-Test chamber, 5-Sample clamping interface, 6-Solenoid valve, 7-Coating sample sheet, 8-Gas collection tube. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example This embodiment provides a device for measuring the room temperature permeability of casting coatings, the structure of which is as follows: Figure 1 As shown, it mainly includes the main body 1 of the intelligent air permeability tester, the vacuum pump 2, the central controller 3, the multi-channel parallel test expansion module, and the intelligent environmental compensation and self-calibration unit.

[0026] The main body of the intelligent air permeability tester forms the core framework of the instrument, integrating circuit boards, air path interfaces, and a display and operation panel. A vacuum pump, connected to the air inlet of the main body via flexible tubing, provides the vacuum source required for testing. The central controller employs an industrial-grade embedded computer, running dedicated test control and data analysis software, and is connected to various sensors and actuators within the main body via cables.

[0027] The multi-channel parallel testing expansion module is a key component of this embodiment. It features a detachable design and connects to the main body of the measuring instrument via a standard quick-connect interface. In this embodiment, the module specifically adopts a "one-pump, two-chamber" configuration, meaning that one vacuum pump simultaneously provides vacuum to two independent test chambers 4 through a gas collection pipeline. Each test chamber includes: A cylindrical sealed chamber with a sample clamping interface 5 at the top for mounting standard-sized coating sample pieces 7. A high-precision pressure sensor is used to monitor changes in air pressure inside the cavity in real time; An independent gas path control solenoid valve 6 is installed on the pipeline between the chamber and the gas collection pipe 8. Its opening and closing are controlled by the central controller, thereby realizing independent control and timing of the vacuuming process of the chamber.

[0028] The two test chambers have identical structures and are arranged symmetrically. They are connected in parallel through gas collecting pipes and then connected to the vacuum pump. Specifically, the test chambers are connected to the main body of the measuring instrument through gas collecting pipes, and then the main body of the measuring instrument is connected to the vacuum pump.

[0029] The intelligent environmental compensation and self-calibration unit is integrated inside the main body of the measuring instrument, including: Temperature and humidity sensor: installed in a ventilated area of ​​the instrument housing, used to collect the temperature (T) and relative humidity (RH) of the test environment in real time; Built-in standard calibration strip: with known, stable and accurate air permeability values, installed in a dedicated calibration station inside the instrument; Embedded microprocessor: Communicates with the central controller, and its internal memory stores environmental compensation algorithms and self-calibration programs.

[0030] In addition, the device in this embodiment is also equipped with a sample preparation module, which is independent of the measuring instrument. The module includes a constant temperature oven that can keep the temperature constant at 105±5℃, and a set of stainless steel molds for preparing standard circular coating samples.

[0031] The central controller's software system is also equipped with a data fusion module, which can automatically process the data obtained from dual-channel testing, calculate the average value, standard deviation, and consistency deviation index, and generate a comprehensive test report.

[0032] The specific implementation steps of the method are as follows: Two 1.0 mm thick lost foam coating samples were placed into the dual test chamber and tightened to 1.8 N·m using a torque wrench.

[0033] The system reads the environmental parameters: T=25℃, RH=60%.

[0034] The test was started, and the two chambers were simultaneously evacuated. The measured values ​​were Δt1 = 14.8 s and Δt2 = 15.1 s. Δt1 and Δt2 represent the time required for the two test chambers to be evacuated from atmospheric pressure to a specific negative pressure during the evacuation process.

[0035] Calculate the permeability coefficients (uncompensated): K1 = 5.12, K2 = 5.01. In the negative pressure method for determining the permeability of casting coatings, the permeability coefficient K is usually inversely proportional to the time Δt required for the gas to pass through the sample and reach the set pressure difference. The shorter the time Δt, the faster the gas passes through, and the greater the permeability value. Therefore, the basic calculation relationship can be expressed as: K = C / Δt, where, K: permeability coefficient (uncompensated); Δt: time required for the gas to pass through the sample and make the system reach the set negative pressure; C: instrument constant (calibrated using a standard sample).

[0036] Environmental compensation (let α = 0.005 / ℃, β=0.002 / %RH): K 1补偿 =5.12×[1 0.005×(25 20)+0.002×(60 50)]=5.12×1.015=5.20, K 2补偿 =5.01 × 1.015 = 5.09 Output average air permeability: K_avg=5.15, consistency deviation K = 2.1% (<5%, results are reliable).

[0037] Self-calibration: The system prompts for self-calibration; please insert the standard calibration piece (calibration value K). 标 =10.0).

[0038] Test yielded K 测 =10.32, the deviation is +3.2%>3%, the system automatically updates the pressure sensor gain coefficient to 10.0 / 10.32=0.969 of the original coefficient, and the calibration is completed.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An apparatus for measuring the air permeability of casting coatings at room temperature, comprising an intelligent air permeability measuring instrument body, a vacuum pump connected to the measuring instrument body, and a central controller, characterized in that, Also includes: A multi-channel parallel testing expansion module is connected to the main body of the measuring instrument. The multi-channel parallel testing expansion module includes at least two independent testing chambers. Each testing chamber is equipped with a pressure sensor, an independent gas path control solenoid valve, and a sample clamping interface. The testing chamber is connected to the main body of the measuring instrument through a gas collection pipe, and then the main body of the measuring instrument is connected to a vacuum pump. The intelligent environmental compensation and self-calibration unit is integrated into the main body of the measuring instrument, including a temperature and humidity sensor for collecting the temperature and humidity of the test environment, a built-in standard calibration plate, and an embedded microprocessor storing environmental compensation algorithms and self-calibration programs. The central controller is used to synchronously control the testing process of each test chamber and to call the environmental compensation algorithm to process the test data.

2. The apparatus for determining the room temperature permeability of casting coatings according to claim 1, characterized in that, The multi-channel parallel test expansion module is a detachable accessory.

3. The apparatus for determining the room temperature permeability of casting coatings according to claim 1, characterized in that, The multi-channel parallel test expansion module adopts a one-pump dual-chamber configuration, and the independent vacuuming and timing of each chamber is achieved by switching through solenoid valves.

4. The apparatus for determining the room temperature permeability of casting coatings according to claim 1, characterized in that, The built-in standard calibration strip has a known and stable air permeability value, which is used for the system to automatically calibrate periodically.

5. The apparatus for determining the room temperature permeability of casting coatings according to claim 1, characterized in that, The device also includes a sample preparation module, which includes a constant temperature oven and a sample mold for preparing standard coating sample pieces.

6. The apparatus for determining the room temperature permeability of casting coatings according to claim 1, characterized in that, The central controller is also equipped with a data fusion module, which is used to calculate the average value and consistency deviation index of multi-channel test results.

7. A method for determining the air permeability of casting coatings at room temperature, using the apparatus described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Prepare at least two coating sample pieces from the same batch and load them into a multi-channel test chamber; S2: Real-time acquisition of ambient temperature and humidity data; S3: Start multi-channel parallel testing, simultaneously evacuate each chamber and record the pressure change time; S4: Calculate the air permeability coefficient of each sample based on the pressure change time; S5: Compensation and correction of air permeability coefficient based on environmental parameters; S6: Output the test results.

8. The method for determining the room temperature air permeability of casting coatings according to claim 7, characterized in that, The consistency evaluation of the air permeability coefficient is calculated using the following formula: Wherein, K1 and K2 are the air permeability coefficients measured in each channel. If ΔK > 5%, the system will indicate that the sample is abnormal.

9. The method for determining the room temperature air permeability of casting coatings according to claim 7, characterized in that, Environmental compensation is based on the following formula: Where T0=20℃ and RH0=50% are standard environmental reference values, and α and β are material property related compensation coefficients.

10. The method for determining the room temperature air permeability of casting coatings according to claim 7, characterized in that, The test results include the compensated air permeability coefficient K of the two samples. 1补偿 K 2补偿 Average air permeability coefficient K avg And consistency deviation ΔK.

Images