Gas-electricity integrated ignition head device for automatic flash point tester and control method of gas-electricity integrated ignition head device

Abstract

The invention relates to a gas-electricity integrated ignition head device for an automatic flash point tester and a control method thereof.The gas-electricity integrated ignition head device comprises an ignition head and a control system, the ignition head comprises an alundum tube, a thermocouple, a gas ignition needle and a silicon nitride ignition head, and four through holes are evenly distributed in the alundum tube; two wires of the thermocouple, the fuel gas ignition needle and the silicon oxide ignition head are respectively inserted into four through holes of the alundum tube and are fixed, the silicon oxide ignition head and the fuel gas ignition needle are on the same horizontal plane, a temperature sensing point of the thermocouple is 5 mm above the fuel gas ignition needle, and combustible gas is guided into the tail end of the fuel gas ignition needle through a gas guide tube. An electromagnetic valve and a fine adjustment needle valve are connected to the gas guide pipe in series, the silicon nitride ignition head is connected into a direct-current power source and connected with a normally-open relay in series, and the electromagnetic valve, the normally-open relay and the thermocouple are all electrically connected with the control system. Automatic free switching between gas ignition and electronic ignition can be achieved, and the flame size and the electronic ignition aging degree can be detected.

Description

Technical Field

[0001] The invention relates to the technical field of oil flash point determination, in particular to a gas-electric integrated ignition head device for an automatic flash point determination instrument and a control method thereof. Background Art

[0002] Flash point refers to the lowest temperature at which the test flame causes the sample vapor to ignite and the flame to spread to the surface of the liquid under specified test conditions. According to the application of different oil products in various industries, flash point is a basic indicator of oil performance. Flash point is divided into open flash point and closed flash point. The most commonly used standards for the determination of open flash point and closed flash point in China are GB / T3536-2008 "Cleveland Open Cup Method for Determination of Flash Point and Ignition Point of Petroleum Products" and GB / T261-2021 "Pensky-Martin Closed Cup Method for Determination of Flash Point". The test flames required for these two determination methods are both gas flames, which means that the gas burns at the front end of an ignition needle with an aperture of 0.8mm, and the flame diameter is maintained at 3.2-4.8mm through a fine-tuning valve.

[0003] There are obvious disadvantages in using a gas flame as a test flame:

[0004] (1) Flash point testing is basically done in oil analysis laboratories, which usually have various flammable substances. Open flames are very dangerous in oil analysis laboratories. Currently, many laboratories clearly stipulate that gas flames cannot be used as test fires.

[0005] (2) Gas flames are greatly affected by external factors. Since the flame is small, a slight airflow may extinguish the flame, resulting in the flash point not being measured during the measurement process while the sample continues to be heated. In the worst case, the test will be invalid, or a fire may occur when the sample reaches the ignition point.

[0006] (3) The fuel gas usually used is liquefied gas. The quality of the liquefied gas and the amount of gas in the gas cylinder may affect the size of the test flame. The size of the flame directly reflects the temperature of the test flame. Too high or too low a temperature will cause the test result to be too low or too high.

[0007] Since many laboratories clearly stipulate that gas flames cannot be used as test fires, many flash point instrument manufacturers at home and abroad have introduced electronic ignition heads, but electronic ignition heads also have obvious disadvantages:

[0008] (1) Electronic ignition heads have a service life. Depending on the frequency and intensity of use, the ignition head will age, the heating area will change, the temperature will drop, or even no heat will occur. In this case, the flash point temperature may be delayed or even not be tested during the test, and there is a risk of fire after the sample reaches the ignition point.

[0009] (2) GB / T261, 6.1 states: "Note: In some cases, there may be differences in the test results using electronic ignition sources and flame ignition sources. In case of dispute, unless otherwise specified, the arbitration test shall be based on the manual test results using flame ignition sources." It can be seen from this that the flash point value of the electronic ignition head test cannot be used as an arbitration result.

[0010] Although some flash point tester manufacturers have introduced the function of freely switching between gas ignition and electronic ignition, the so-called free switching means manually dismantling the original ignition head, replacing it with the ignition head that needs to be replaced, and then changing the ignition method through the software. This requires a relatively high level of hands-on ability of the operator, and also has relatively high requirements for the installation accuracy after replacement. Summary of the invention

[0011] In view of the above problems, the present invention provides a gas-electric integrated ignition head device for an automatic flash point tester and a control method thereof, which can realize free switching between gas ignition and electronic ignition and monitor the flame size and the degree of aging of electronic ignition.

[0012] The technical solution adopted by the present invention to solve the above technical problems is: a gas-electric integrated ignition head device for an automatic flash point tester, including an ignition head and a control system, the ignition head including a corundum tube, a thermocouple, a gas ignition needle and a silicon nitride ignition head, the corundum tube is evenly distributed with four through holes along the tube length direction, the silicon oxide ignition head includes two wires, the thermocouple, the gas ignition needle and the two wires of the silicon oxide ignition head are respectively inserted into the four through holes of the corundum tube and fixed, the silicon oxide ignition head and the gas ignition needle are on the same horizontal plane, the temperature sensing point of the thermocouple is 5 mm above the gas ignition needle, and the length of the thermocouple, the gas ignition needle and the silicon nitride ignition head extending from the corundum tube through hole is 3 cm.

[0013] Furthermore, the tail end of the gas ignition needle introduces combustible gas through an air guide pipe, and a solenoid valve and a fine-tuning needle valve are connected in series in sequence on the air guide pipe along the direction of the combustible gas introduction. The solenoid valve is controlled by a control system to turn on and off the gas. The silicon nitride ignition head is connected to a DC power supply and is connected in series with a normally open relay. The output end of the normally open relay is electrically connected to the control system, and the thermocouple is electrically connected to the control system. At the same time, the thermocouple collects the flame temperature of the gas ignition needle or the temperature of the silicon nitride ignition head and transmits it to the control system through a signal.

[0014] Furthermore, the corundum tube is cylindrical and has an outer diameter of 1 to 9 mm, and an inner diameter of each through hole is 1.8 to 2.2 mm.

[0015] Furthermore, the thermocouple has a temperature resistance of more than 800 degrees and is packaged by a stainless steel tube. The outer diameter of the stainless steel tube and the inner diameter of the through hole of the corundum tube have a negative tolerance, and the temperature sensing point at the front end of the thermocouple extends 5 mm out of the stainless steel tube.

[0016] Furthermore, the gas ignition needle is a stainless steel capillary with an inner diameter of 0.8 to 1.0 mm, the outer diameter of the stainless steel capillary and the inner diameter of the through hole of the corundum tube have a negative tolerance, the front end of the stainless steel capillary is chamfered for 10 mm, the tip of the stainless steel capillary has a wall thickness of 0.1 mm and is bent at 5 mm from the tip to form an angle of 150 degrees with the stainless steel capillary.

[0017] Furthermore, the silicon oxide ignition head is a bare wire package, the heating zone of the silicon oxide ignition head is the 5mm length zone of the wire tip, and the wire diameter of the heating zone is 3mm, the rated power of the heating zone is 120W, and the diameter of the wire and the inner diameter of the through hole of the corundum tube have a negative tolerance.

[0018] Furthermore, the tips of the gas ignition needle and the silicon nitride ignition head are oriented in the same direction as the temperature sensing point of the thermocouple.

[0019] The present invention also provides a control method for a gas-electric integrated ignition head device for an automatic flash point tester, the method comprising:

[0020] S1, install the device on the automatic flash point tester and start the test;

[0021] S2, the device enters the working state, and the control system determines whether it is gas ignition;

[0022] S3, when the control system identifies gas ignition, it opens the solenoid valve, executes the ignition action of the silicon nitride ignition head, and determines whether the temperature detected by the thermocouple is maintained at 800℃±20℃;

[0023] S301, if the judgment in S3 is yes, the flame is kept, and the thermocouple continuously collects the temperature during the whole test process;

[0024] S302, if the judgment in S3 is no, the silicon nitride ignition head is powered on for three seconds to perform the flame ignition action again, and it is determined whether the ignition action has been performed three times in succession. If the detected temperature is still not reached after three times in succession, the system will report an error prompt;

[0025] S4, when the control system identifies electric ignition, it first performs pre-ignition action. The control system will energize the silicon nitride ignition head for three seconds and determine whether the temperature detected by the thermocouple reaches 650℃±20℃;

[0026] S401, if the judgment of S4 is yes, the pre-ignition action is completed and the flash point test process is entered, waiting for the ignition command to be received, the control system powers on the silicon nitride ignition head for three seconds in advance, and again judges whether the temperature detected by the thermocouple reaches 650℃±20℃;

[0027] S401-1, if the judgment in S401 is yes again, the ignition action continues to be executed;

[0028] S401-2, if the result of S401 is negative, the silicon nitride ignition head is powered on for three seconds to perform the ignition action, and it is determined whether the ignition action has been performed three times in succession. If the temperature detected is still not reached after three times in succession, the system will report an error prompt;

[0029] S402, if it is judged as no by S4, the silicon nitride ignition head is powered on for three seconds to perform the ignition action again, and it is determined whether the ignition action has been performed three times in succession. If the detected temperature is still not reached after three times in succession, the system will give an error prompt.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention can realize automatic and free switching between gas ignition and electronic ignition, and can detect the flame size and the aging degree of electronic ignition, thereby improving the safety factor;

[0032] 2. The present invention ensures the normal operation of the ignition action during the entire test process, whether gas ignition or electric ignition is selected, prevents the flame from being extinguished by external air flow disturbance and aging of the silicon nitride ignition head, and avoids the problem of open flame incidents caused by continuous heating after the sample reaches the flash value because the flash point value cannot be measured;

[0033] 3. The present invention realizes the free switching between gas ignition and electronic ignition through automation, does not require manual adjustment, and is more in line with market demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the present invention;

[0035] Figure 2 It is a schematic diagram of the explosion of the ignition head in the present invention;

[0036] Figure 3 It is a schematic diagram of the ignition head structure in the present invention;

[0037] Figure 4 It is a flow chart of the control system of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined Figure 1-4 The present invention is described in detail. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0039] A gas-electric integrated ignition head device for an automatic flash point tester comprises an ignition head 11 and a control system 5. The ignition head comprises a corundum tube 1, a thermocouple 2, a gas ignition needle 3 and a silicon nitride ignition head 4. Figure 3As shown, the corundum tube is provided with four through holes evenly distributed along the tube length direction, the silicon oxide ignition head comprises two wires, the thermocouple, the gas ignition needle and the two wires of the silicon oxide ignition head are respectively inserted into the four through holes of the corundum tube and fixed, the silicon oxide ignition head and the gas ignition needle are in the same horizontal plane, the temperature sensing point of the thermocouple is 5 mm above the gas ignition needle, the length of the thermocouple, the gas ignition needle and the silicon nitride ignition head extending from the through hole of the corundum tube is 3 cm, and when the device is installed on the flash point tester, the tips of the gas ignition needle and the silicon nitride ignition head are kept in the same direction as the temperature sensing point of the thermocouple.

[0040] Specifically, Figure 1 As shown, the tail end of the gas ignition needle is connected to the gas 10 through an air guide pipe, so as to introduce combustible gas. On the air guide pipe, a solenoid valve 6 and a fine-tuning needle valve 7 are connected in series in sequence along the direction of the combustible gas introduction, wherein the solenoid valve is controlled by the control system to turn on and off the gas, and the fine-tuning needle valve can be used to adjust the size of the flame. The silicon nitride ignition head is connected to a DC power supply 8 and connected in series with a normally open relay 9. The output end of the normally open relay is electrically connected to the control system, and the on and off of the output end of the normally open relay is controlled by the control system. The thermocouple is electrically connected to the control system. At the same time, the thermocouple collects the flame temperature of the ignition gas needle or the temperature of the silicon nitride ignition head and transmits it to the control system through a signal to determine whether the flame size of the gas ignition needle or the calorific value of the silicon nitride ignition head meets the requirements.

[0041] Specifically, the corundum tube is cylindrical and has an outer diameter of 1 to 9 mm, and the inner diameter of each through hole is 1.8 to 2.2 mm. In the present device, the corundum tube is used to effectively insulate and fix the thermocouple, the gas ignition needle and the silicon nitride ignition head; the thermocouple is temperature-resistant above 800 degrees and is packaged by a stainless steel tube. The outer diameter of the stainless steel tube and the inner diameter of the through hole of the corundum tube have a negative tolerance, which can just be inserted into the corundum tube without being too loose. The temperature sensing point at the front end of the thermocouple extends 5 mm out of the stainless steel tube; the gas ignition needle is a stainless steel capillary tube with an inner diameter of 0.8 to 1.0 mm. The outer diameter of the stainless steel capillary tube also has a negative tolerance with the inner diameter of the through hole of the corundum tube, which can just be inserted into the corundum tube without being too loose. The front end of the stainless steel capillary is chamfered for 10mm, and the tip of the stainless steel capillary is 0.1mm thick and bent at 5mm from the tip to form an angle of 150 degrees with the stainless steel capillary. The silicon oxide ignition head is a bare wire package, that is, two wires. The heating zone of the silicon oxide ignition head is 5mm in length from the tip of the wire, and the wire diameter in the heating zone is 3mm. The rated power of the heating zone is 120W, and it is required to reach the maximum power within three seconds. Whether the maximum power can be reached within three seconds can be used to test whether the silicon nitride ignition head is qualified. At the same time, the diameter of the wire and the inner diameter of the through hole of the corundum tube have a negative tolerance and just pass through the through hole of the corundum tube.

[0042] During the implementation process, the automatic flash point tester is installed with the gas-electric integrated ignition head device provided by this application. Since the temperature sensing point of the thermocouple is located directly above the gas ignition needle and close to the hot spot of the silicon nitride ignition head, the relative positions of the temperature sensing point and the hot spot are relatively fixed, and the thermocouple can stably collect the temperature of the ignition needle flame and the temperature of the hot spot of the silicon nitride ignition head. Before the test, the gas solenoid valve is manually opened to ignite the flame at the tip of the gas ignition needle. Under the condition of no airflow disturbance, the fine-tuning needle valve is adjusted to keep the flame at the tip of the gas ignition needle at a size of 3.2 to 4.8 mm. The temperature sensing point of the thermocouple is at the outer flame position of the flame. When there is no airflow disturbance, the temperature collected by the thermocouple is 780°C to 820°C. If the temperature collected by the thermocouple is lower than 780°C, it means that the flame is not ignited or the flame size is less than 3.2mm. If the temperature collected by the thermocouple is greater than 820°C, it means that the flame size is greater than 4.8mm. The fine-tuning needle valve can be adjusted to make the flame size at the tip of the ignition needle meet the requirements.

[0043] Extinguish the gas flame of the gas ignition needle and energize the silicon nitride ignition head alone. In the absence of airflow disturbance, the silicon nitride ignition head reaches the maximum temperature within three seconds. At the same time, the temperature collected by the thermocouple reaches a stable state. The collected temperature is 630℃~670℃. Under normal circumstances, the temperature will not increase any further. Only when the silicon nitride ignition head ages will the collected temperature become lower.

[0044] A threshold for issuing an error prompt when the temperature collected by the thermocouple is set in the control system. If the deviation between the temperature collected by the thermocouple and the set temperature reaches the threshold during operation of the gas-electric integrated ignition head device provided in the present application, the control system will perform corrective actions or issue an error prompt.

[0045] After the automatic flash point tester is started, the gas-electric integrated ignition head device provided by the present application enters the working state, such as Figure 4 The control method shown is that the control system first determines whether the operator has selected gas ignition or electric ignition. When the control system recognizes that it is gas ignition, the solenoid valve is opened before heating the sample cup, and the gas is ejected through the front end of the gas ignition needle, starting the silicon nitride ignition head flame ignition action. The thermocouple continuously detects the temperature of the flame at the tip of the gas ignition needle. If the detected temperature is lower than 780°C, the silicon nitride ignition head will be powered on for three seconds to perform the flame ignition action again. If the detected temperature is still lower than 780°C after performing this action three times in a row, the system will give an error prompt: "Please adjust the flame size!" or "Insufficient gas or silicon nitride ignition head failure". If the detected temperature is continuously higher than 820°C, the system will give an error prompt: "Please adjust the flame size!"

[0046] If the detected temperature remains at 800℃±20℃, it is considered that the flame is ignited successfully. Then, the flame maintenance program is executed during the test. During the entire test process, the thermocouple continuously collects temperature. Once the temperature continues to drop, it is judged that the flame is extinguished and the flame ignition action is executed again.

[0047] When the system identifies it as electric ignition, it will perform pre-ignition before heating the flash point sample cup. The control system will energize the silicon nitride ignition head for three seconds, and the thermocouple will detect whether the temperature reaches 650℃±20℃. The thermocouple should collect the highest temperature within three seconds. If the highest temperature reaches 650℃±20℃, it is considered that the ignition head is working normally. If it is lower than this temperature, the ignition action will be performed again. If the temperature collected by the thermocouple cannot reach 650℃±20℃ after three consecutive ignition actions, the system will give an error prompt: "Silicon nitride ignition head failure".

[0048] After completing the pre-ignition action, the silicon nitride ignition head works normally, and the automatic flash point tester enters the flash point test process, waiting to receive the ignition command. When the flash point ignition conditions are met, the control system will power on the silicon nitride ignition head for three seconds three seconds in advance. At the same time, the thermocouple detects whether the maximum temperature of the silicon nitride ignition head reaches 650℃±20℃. If the temperature is reached, it is judged that the silicon nitride ignition head works normally, and the ignition action continues. If it is lower than the temperature, the silicon nitride ignition head is powered on for three seconds again to perform the ignition action. If the temperature collected by the thermocouple cannot reach 650℃±20℃ after the silicon nitride ignition head is powered on for three seconds for three consecutive times, the system will give an error prompt: "Silicon nitride ignition head failure".

[0049] This device ensures the normal operation of the ignition action during the entire test process, regardless of whether gas ignition or electric ignition is selected, to prevent the flame from being extinguished by external airflow disturbances, aging of the silicon nitride ignition head, and the inability to measure the flash point value after the sample reaches the flash point value, resulting in continuous heating and causing open flame events.

[0050] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A gas-electric integrated ignition head device for an automatic flash point tester, characterized in that: The invention comprises an ignition head (11) and a control system (5), wherein the ignition head comprises a corundum tube (1), a thermocouple (2), a gas ignition needle (3) and a silicon nitride ignition head (4), wherein the corundum tube is provided with four through holes evenly distributed along the tube length direction, and the silicon oxide ignition head comprises two wires, wherein the thermocouple, the gas ignition needle and the two wires of the silicon oxide ignition head are respectively inserted into the four through holes of the corundum tube and fixed, wherein the silicon oxide ignition head and the gas ignition needle are in the same horizontal plane, the temperature sensing point of the thermocouple is 5 mm above the gas ignition needle, and the length of the thermocouple, the gas ignition needle and the silicon nitride ignition head extending from the through hole of the corundum tube is 3 cm.

2. The gas-electric integrated ignition head device for the automatic flash point tester according to claim 1, characterized in that: The tail end of the gas ignition needle is introduced into the combustible gas through an air guide pipe, and the air guide pipe is connected in series with an electromagnetic valve (6) and a fine-tuning needle valve (7) in sequence along the direction of the combustible gas introduction. The electromagnetic valve is controlled by a control system to turn the gas on and off. The silicon nitride ignition head is connected to a DC power supply (8) and is connected in series with a normally open relay (9). The output end of the normally open relay is electrically connected to the control system, and the thermocouple is electrically connected to the control system. At the same time, the thermocouple collects the flame temperature of the gas ignition needle or the temperature of the silicon nitride ignition head and transmits it to the control system through a signal.

3. The gas-electric integrated ignition head device for the automatic flash point tester according to claim 1, characterized in that: The corundum tube is cylindrical and has an outer diameter of 1 to 9 mm, and the inner diameter of each through hole is 1.8 to 2.2 mm.

4. The gas-electric integrated ignition head device for the automatic flash point tester according to claim 1, characterized in that: The thermocouple has a temperature resistance of more than 800 degrees and is packaged by a stainless steel tube. The outer diameter of the stainless steel tube and the inner diameter of the through hole of the corundum tube have a negative tolerance. The temperature sensing point at the front end of the thermocouple extends 5mm out of the stainless steel tube.

5. The gas-electric integrated ignition head device for the automatic flash point tester according to claim 1, characterized in that: The gas ignition needle is a stainless steel capillary with an inner diameter of 0.8 to 1.0 mm. The outer diameter of the stainless steel capillary and the inner diameter of the through hole of the corundum tube have a negative tolerance. The front end of the stainless steel capillary is chamfered for 10 mm. The tip of the stainless steel capillary has a wall thickness of 0.1 mm and is bent at 5 mm from the tip to form an angle of 150 degrees with the stainless steel capillary.

6. The gas-electric integrated ignition head device for the automatic flash point tester according to claim 1, characterized in that: The silicon oxide ignition head is a bare wire package, the heating zone of the silicon oxide ignition head is the 5mm length zone of the wire tip, the wire diameter of the heating zone is 3mm, the rated power of the heating zone is 120W, and the diameter of the wire and the inner diameter of the through hole of the corundum tube have a negative tolerance.

7. The gas-electric integrated ignition head device for the automatic flash point tester according to claim 1, characterized in that: The tips of the gas ignition needle and the silicon nitride ignition head are kept in the same direction as the temperature sensing point of the thermocouple.

8. The control method of the gas-electric integrated ignition head device for the automatic flash point tester according to any one of claims 1 to 7, characterized in that: The method includes: S1, install the device on the automatic flash point tester and start the test; S2, the device enters the working state, and the control system determines whether it is gas ignition; S3, when the control system identifies gas ignition, it opens the solenoid valve, executes the ignition action of the silicon nitride ignition head, and determines whether the temperature detected by the thermocouple is maintained at 800℃±20℃; S301, if the judgment in S3 is yes, the flame is kept, and the thermocouple continuously collects the temperature during the whole test process; S302, if the judgment in S3 is no, the silicon nitride ignition head is powered on for three seconds to perform the flame ignition action again, and it is determined whether the ignition action has been performed three times in succession. If the detected temperature is still not reached after three times in succession, the system will report an error prompt; S4, when the control system identifies electric ignition, it first performs pre-ignition action. The control system will energize the silicon nitride ignition head for three seconds and determine whether the temperature detected by the thermocouple reaches 650℃±20℃; S401, if the judgment of S4 is yes, the pre-ignition action is completed and the flash point test process is entered, waiting for the ignition command to be received, the control system powers on the silicon nitride ignition head for three seconds in advance, and again judges whether the temperature detected by the thermocouple reaches 650℃±20℃; S401-1, if the judgment in S401 is yes again, the ignition action continues to be executed; S401-2, if the result of S401 is negative, the silicon nitride ignition head is powered on for three seconds to perform the ignition action, and it is determined whether the ignition action has been performed three times in succession. If the temperature detected is still not reached after three times in succession, the system will report an error prompt; S402, if it is judged as no by S4, the silicon nitride ignition head is powered on for three seconds to perform the ignition action again, and it is determined whether the ignition action has been performed three times in succession. If the detected temperature is still not reached after three times in succession, the system will give an error prompt.

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