A device, apparatus and method for testing a constant flow orifice with a standard resistance rod

Abstract

The application discloses a kind of constant flow orifice and suction resistance standard stick detection device, equipment and method, device includes constant flow orifice during detection system, and suction resistance standard stick during detection system, constant flow orifice during detection system and suction resistance standard stick during detection system share negative pressure generator, differential pressure gauge, thermometer, barometer and processing system;Processing system is used to calculate the flow of the constant flow orifice to be detected according to the data measured by differential pressure gauge, thermometer, barometer, whether the flow of the constant flow orifice to be detected meets the standard is judged;And compare the suction resistance value of the suction resistance standard stick to be detected with the suction resistance standard value of the detected specification suction resistance standard stick, to carry out during detection to constant flow orifice and suction resistance standard stick.The application can be integrated with high degree, can carry out switching detection to constant flow orifice and suction resistance standard stick, exclude the influence caused by the deviation of constant flow orifice or suction resistance standard stick in production process.

Description

Technical Field

[0001] This invention relates to the field of cigarette equipment technology, specifically to a detection device, equipment, and method for a constant flow orifice and a suction resistance standard rod. Background Technology

[0002] The tobacco-specific draw resistance standard rod is a standard instrument used on the tobacco-specific draw resistance tester. The calibration of the tobacco-specific draw resistance standard rod involves measuring the pressure difference across the two ends of the standard rod in the gas path under a gas flow rate of (17.5±0.3) mL / s, and then calculating the calibration value of the tobacco-specific draw resistance standard rod.

[0003] The Critical Flow Orifice (CFO) is a standard instrument used in various tobacco-specific testing instruments, such as suction resistance testers, ventilation rate testers, and smoking machine suction curve testers. Its main function is to keep the gas flow rate constant to meet the measurement requirements.

[0004] Furthermore, the calibration process for both the suction resistance standard rod and the constant flow orifice requires disassembly and delivery to a specialized institution for testing. The calibration cycle is typically once a year, which is too long. This makes it impossible to guarantee the stability of the suction resistance standard rod and the constant flow orifice during the two calibrations that are one year apart. Therefore, it is necessary to perform periodic testing during daily use to ensure that the airflow in the gas path remains stable within the required measurement range and to confirm that the actual measured value of the suction resistance standard rod does not differ significantly from the calibration value.

[0005] The suction resistance meter can be used to measure the suction resistance standard bar, but due to the pressure drop in the pipeline between the probe of the suction resistance meter and the constant flow orifice, as well as the difference in working principle, it cannot achieve accurate measurement of the suction resistance standard bar.

[0006] Therefore, there is an urgent need for a device to perform intermittent detection of a constant flow orifice and a suction resistance standard bar, so as to adapt to the joint detection of a constant flow orifice and a suction resistance standard bar. Summary of the Invention

[0007] The purpose of this invention is to provide a detection device, equipment, and method for a constant flow orifice and a suction resistance standard bar, in order to solve the technical problems existing in the background art.

[0008] The technical solution adopted in this invention is as follows:

[0009] A detection device for a constant flow orifice and a suction resistance standard bar includes a constant flow orifice detection system for detecting the constant flow orifice and a suction resistance standard bar detection system for detecting the suction resistance standard bar. The constant flow orifice detection system and the suction resistance standard bar detection system share a negative pressure generator, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system.

[0010] The constant flow orifice detection system includes a negative pressure generator, a constant flow orifice fixture for mounting the constant flow orifice to be detected, a dryer, a mass flow meter, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system. The negative pressure generator, the constant flow orifice fixture, the dryer, and the mass flow meter are arranged in sequence.

[0011] The suction resistance standard bar detection system includes a negative pressure generator, a constant flow orifice, a filter, a suction resistance standard bar clamp for mounting the suction resistance standard bar, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system. The negative pressure generator, the constant flow orifice, the filter, and the suction resistance standard bar clamp are arranged in sequence.

[0012] When periodic testing of a constant flow orifice is required, the negative pressure generator is connected to the constant flow orifice fixture, and the differential pressure gauge is connected between the dryer and the constant flow orifice to be tested, for measuring the pressure difference between the constant flow orifice and the atmosphere. When periodic testing of a suction resistance standard rod is required, the negative pressure generator is connected to the constant flow orifice, and the differential pressure gauge is connected between the filter and the suction resistance standard rod fixture, for measuring the pressure difference between the suction resistance standard rod fixture and the atmosphere. The processing system is used to determine whether the flow rate of the constant flow orifice and the suction resistance value of the suction resistance standard rod meet the standards based on the pressure difference measured by the differential pressure gauge, the atmospheric temperature measured by the thermometer, and the atmospheric pressure measured by the barometer, thereby realizing periodic testing of the constant flow orifice or suction resistance standard rod.

[0013] As a further technical solution, the suction resistance standard rod clamp and the constant flow orifice clamp are provided with sealing rings.

[0014] As a further technical solution, the sealing ring is a rubber diaphragm.

[0015] As a further technical solution, the negative pressure generator is connected to the constant flow orifice clamp and the constant flow orifice respectively through a three-way interface; the differential pressure gauge is connected between the dryer and the constant flow orifice clamp, or between the filter and the suction resistance standard rod clamp, through a three-way interface.

[0016] Meanwhile, a detection device for a constant flow orifice and a suction resistance standard bar is also proposed, including the detection device for a constant flow orifice and a suction resistance standard bar as described above, as well as a chassis and a computer monitor mounted on top of the chassis.

[0017] The chassis is equipped with a detection switch, a first switching switch, a second switching switch, a suction resistance standard rod clamp, and a constant flow orifice clamp. The detection switch is used to connect the compressed air to the negative pressure generator to generate negative pressure. The first switching switch is connected to a first switching valve of the negative pressure generator at one end, and is used to control the connection switching of the other end of the first switching valve to connect the constant flow orifice or the constant flow orifice clamp. The second switching switch is connected to a second switching valve of the differential pressure gauge at one end, and is used to control the connection of the other end of the second switching valve between the suction resistance standard rod clamp and the filter, or between the constant flow orifice clamp and the dryer.

[0018] As a further technical solution, the compressed air is also connected to the negative pressure generator through a connecting valve, and the connecting valve is located on the rear side of the chassis. The connecting valve is controlled by a detection switch.

[0019] As a further technical solution, the chassis is also equipped with a positive pressure gauge and a negative pressure gauge. The positive pressure gauge is connected to the introduced atmosphere and is used to display the pressure value of the positive pressure gas; the negative pressure gauge is connected to the introduced compressed air and is used to display the pressure value of the negative pressure gas.

[0020] In addition, a method for detecting a constant flow orifice and a suction resistance standard bar is proposed, which is implemented using the detection device for a constant flow orifice and a suction resistance standard bar as described above. The specific steps are as follows:

[0021] Step S1: When it is necessary to detect a constant flow orifice, connect the constant flow orifice detection system, collect the pressure difference P1 between the atmosphere and the constant flow orifice to be detected measured by the differential pressure gauge, the absolute atmospheric pressure P2 measured by the atmospheric pressure gauge, and calculate the inlet pressure P of the constant flow orifice to be detected.

[0022] Step S2: Collect the atmospheric temperature T measured by the thermometer;

[0023] Step S3: The processing system uses the data collected in steps S1 and S2 to calculate the flow rate Q of the constant flow orifice to be detected. (P,T) Determine the flow rate Q of the constant flow orifice to be tested. (P,T) Whether the constant flow rate orifice can be tested within the standard flow rate range of the tested specification;

[0024] Step S4: When testing the suction resistance standard rod, connect the suction resistance standard rod detection system and collect the pressure difference P3 between the atmosphere and the outlet of the suction resistance standard rod to be tested, measured by the differential pressure gauge; the absolute atmospheric pressure P2 measured by the atmospheric barometer; and the atmospheric temperature T measured by the thermometer. The pressure difference P3 is the suction resistance value PD of the suction resistance standard rod to be tested under the atmospheric temperature T and the absolute atmospheric pressure P2. Meas ;

[0025] Step S5: The processing system uses the data collected in step S4 to compare the resistance value of the suction resistance standard bar to be tested with the standard resistance value of the suction resistance standard bar of the specified specification, so as to realize the periodic detection of the suction resistance standard bar.

[0026] As a further technical solution, in step S3, the processing system uses the collected data to calculate the flow rate Q of the constant flow orifice. (P,T) The formula is:

[0027]

[0028] Among them, P N Atmospheric pressure under standard conditions; T N The temperature under standard conditions; Q N Z represents the flow rate under standard conditions. N Z represents the gas compressibility factor under standard conditions; P represents the inlet pressure of the constant flow orifice to be tested; T represents the air temperature at the inlet of the constant flow orifice to be tested under actual conditions, i.e., the atmospheric temperature measured by the thermometer; ... air temperature at the inlet pressure of the constant flow orifice to be tested. (P,T) The compressibility factor of the air outlet of a constant flow orifice fixture or constant flow orifice under actual conditions.

[0029] As a further technical solution, step S5 also includes correcting the resistance value of the standard bar to be tested by the processing system, as follows:

[0030] α=ΔT×(a1+a2×PD Meas )+ΔP atm ×(a3+a4×PD Meas )+a5×ΔRH+a6×(ΔP atm ) 2 ;

[0031]

[0032] Where: PD is the corrected absorption resistance value, in Pa; α is the correction factor under different temperature, humidity and atmospheric pressure conditions; PD Meas ΔT is the measured absorption resistance value, in mmWG; ΔT is the difference between the measured temperature and 22℃, in℃; ΔP atm The difference between measured atmospheric pressure and 101325 Pa is expressed in mmWG; ΔRH is expressed as the difference between measured relative humidity and 60%RH, expressed in %RH; a1 = -2.404 × 10⁻¹; a2 = -2.240 × 10⁻⁵; a3 = -2.891 × 10⁻³; a4 = -6.678 × 10⁻⁶; a5 = -2.707 × 10⁻³; a6 = 7.386 × 10⁻⁶.

[0033] The corrected suction resistance value PD is compared with the standard suction resistance value of the suction resistance standard bar to verify the suction resistance standard bar.

[0034] Beneficial effects

[0035] This invention can integrate periodic testing of constant flow orifice and suction resistance standard bar, eliminating the impact of deviations in constant flow orifice or suction resistance standard bar during the production process;

[0036] Furthermore, by setting up a dryer to remove moisture from the atmosphere, the constant flow rate orifice to be tested is prevented from being damaged by moisture, thus ensuring the quality of the constant flow rate orifice to be tested. By setting up a filter, the quality of the constant flow rate orifice can be guaranteed, and blockage of the constant flow rate orifice during the test process can be avoided, which would affect the accuracy of the suction resistance standard bar test and thus improve the test effect.

[0037] In addition, by setting a sealing ring inside the constant flow orifice fixture and the suction resistance standard rod fixture, the sealing ring is made of a rubber diaphragm, which can prevent the constant flow orifice fixture and the suction resistance standard rod fixture from being connected to the air, and can also ensure the airflow when the suction resistance standard rod is inserted into the suction resistance standard rod fixture and the constant flow orifice is inserted into the constant flow orifice fixture. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a detection device for a constant flow orifice and a suction resistance standard bar in Example 1;

[0039] Figure 2 This is a reference figure showing the relationship between the air compressibility factor and temperature and absolute pressure of the constant flow orifice fixture or constant flow orifice under actual conditions in Example 1.

[0040] Figure 3 This is a schematic diagram of the structure of a detection device for a constant flow orifice and a suction resistance standard bar in Example 2;

[0041] Figure 4 This is a schematic diagram of the differential pressure gauge in Example 2;

[0042] Figure 5 This is a schematic diagram of the mass flow meter in Example 2;

[0043] Figure 6 This is an external structural diagram of the constant flow orifice fixture in Example 3;

[0044] Figure 7 This is a three-dimensional cross-sectional view of the constant flow orifice fixture in Example 3;

[0045] Figure 8 This is a cross-sectional schematic diagram of the constant flow orifice fixture in Example 3.

[0046] Illustration:

[0047] 1. Chassis; 2. Computer monitor; 3. Positive pressure gauge; 4. Negative pressure gauge; 5. First switching switch; 6. Detection switch; 7. Suction resistance standard rod clamp; 8. Constant flow orifice clamp; 9. Second switching switch; 10. Differential pressure gauge; 11. Mass flow meter; 81. Base; 82. Upper pressure ring; 83. Top cover; 84. Constant flow orifice; 85. Rubber diaphragm; 86. O-ring seal. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0049] Conversely, this application covers any substitutions, modifications, equivalent methods, and schemes made within the spirit and scope of this application as defined in the claims. Furthermore, to provide the public with a better understanding of this application, certain specific details are described in detail below. However, this application can be fully understood by those skilled in the art even without these detailed descriptions.

[0050] Example 1

[0051] See attached document Figure 1 A detection device for a constant flow orifice and a suction resistance standard bar includes a constant flow orifice period detection system and a suction resistance standard bar period detection system. The constant flow orifice period detection system and the suction resistance standard bar period detection system share a negative pressure generator, differential pressure gauge, thermometer, atmospheric pressure gauge, and processing system, so as to realize the separate detection of the constant flow orifice and the suction resistance standard bar through the period detection device.

[0052] Specifically, the constant flow orifice detection system includes a negative pressure generator, a constant flow orifice fixture for mounting the constant flow orifice to be tested, a dryer, a mass flow meter, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system. The negative pressure generator, constant flow orifice fixture, dryer, and mass flow meter are arranged in sequence. The constant flow orifice to be tested is installed on the constant flow orifice fixture. The negative pressure generator generates the negative pressure required for the constant flow orifice to operate. The mass flow meter measures the upstream mass flow rate of the constant flow orifice. The differential pressure gauge measures the pressure difference between the downstream of the mass flow meter and the atmosphere. The thermometer and atmospheric pressure gauge measure the ambient temperature and atmospheric pressure. Then, the processing system converts the upstream and downstream pressure difference of the mass flow meter, the ambient temperature, and the atmospheric pressure into the upstream volumetric flow rate of the constant flow orifice, which is the measurement result of the constant flow orifice flow rate value.

[0053] Furthermore, in the constant flow orifice detection system, the positive port of the negative pressure generator is connected to compressed air, and the negative port of the negative pressure generator is connected to the outlet of the constant flow orifice fixture to provide the negative pressure required for the normal operation of the constant flow orifice. The exhaust port of the negative pressure generator is connected to the atmosphere. The inlet of the constant flow orifice fixture is connected to the outlet of the dryer, and the inlet of the dryer is connected to the inlet of the mass flow meter, which is connected to the atmosphere through the inlet of the mass flow meter. In this embodiment, the compressed air is generated by a compressor or compressed air source and connected to the positive port of the negative pressure generator to provide an air source for the negative pressure generator. A dryer is connected in series between the inlet of the constant flow orifice fixture and the outlet of the mass flow meter to remove moisture from the atmosphere, preventing damage to the constant flow orifice to be detected due to moisture ingress. A differential pressure gauge is installed between the constant flow orifice fixture and the dryer, located at the inlet of the constant flow orifice fixture, to measure the pressure difference between the constant flow orifice inlet and the atmosphere.

[0054] The suction resistance standard bar period detection system includes a negative pressure generator, a constant flow orifice, a filter, a suction resistance standard bar clamp for mounting the suction resistance standard bar, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system, etc. The negative pressure generator, constant flow orifice, filter, and suction resistance standard bar clamp are arranged in sequence. In this embodiment, the outlet end of the suction resistance standard bar is inserted into the suction resistance standard bar clamp and sealed by a sealing ring to improve the detection accuracy of the suction resistance standard bar period detection device.

[0055] Furthermore, in the suction resistance standard rod detection system, the positive pressure port of the negative pressure generator is connected to compressed air, and the negative pressure port of the negative pressure generator is connected to the outlet of the constant flow orifice, providing the negative pressure required for the normal operation of the constant flow orifice. The exhaust port of the negative pressure generator is connected to the atmosphere. The inlet of the constant flow orifice is connected to the outlet of the filter, and the inlet of the filter is connected to the outlet of the suction resistance standard rod clamp. The filter is placed between the constant flow orifice and the suction resistance standard clamp to ensure that various tobacco impurities cannot enter the constant flow orifice. The outlet of the suction resistance standard rod is inserted into the suction resistance standard rod clamp, and the inlet end of the suction resistance standard rod in the clamp is connected to the atmosphere. A differential pressure gauge is placed between the filter and the suction resistance standard rod clamp.

[0056] In this embodiment, the negative pressure generator of the detection device for a constant flow orifice and a suction resistance standard bar is selected according to the equipment being tested. When the constant flow orifice detection system is selected, the negative pressure port of the negative pressure generator is connected to the outlet of the constant flow orifice fixture used to install the constant flow orifice to be tested, and the differential pressure gauge is connected between the inlet of the constant flow orifice fixture and the outlet of the dryer. When the suction resistance standard bar detection system is selected, the negative pressure port of the negative pressure generator is connected to the outlet of the constant flow orifice, and the differential pressure gauge is connected between the outlet of the suction resistance standard bar fixture and the filter. Preferably, the negative pressure port of the negative pressure generator can be connected to the constant flow orifice fixture and the constant flow orifice through a three-way interface, and the differential pressure gauge can also be connected to the constant flow orifice detection system and the suction resistance standard bar detection system through a three-way interface respectively.

[0057] In addition, a method for detecting a constant flow orifice and a suction resistance standard bar is provided. Of course, other methods can also be used for detection; this is just an example. The specific steps are as follows:

[0058] S1. When it is necessary to test the constant flow orifice, connect the constant flow orifice detection system, collect the pressure difference P1 between the atmosphere and the constant flow orifice to be tested measured by the differential pressure gauge, and the absolute atmospheric pressure P2 measured by the atmospheric pressure gauge. Calculate the inlet pressure P of the constant flow orifice to be tested. The calculation formula is: P = P2 - P1.

[0059] S2, The atmospheric temperature T measured by the thermometer;

[0060] S3. The processing system uses the collected data to calculate the flow rate Q of the constant flow orifice to be detected according to the following formula. (P,T) Determine the flow rate Q of the constant flow orifice to be tested. (P,T) Whether it is within the standard flow range of the constant flow orifice of the tested specification, so as to achieve periodic testing of the constant flow orifice.

[0061]

[0062] Among them, P N The pressure is atmospheric pressure under standard conditions, typically taken as 101325 Pa; T N The temperature under standard conditions is taken as 273.15 K; Q N Z represents the flow rate under standard conditions. N The gas compressibility factor under standard conditions is 0.99941 for air; P is the inlet pressure of the constant flow orifice to be tested; T is the air temperature at the inlet of the constant flow orifice to be tested under actual conditions, which is the same as the atmospheric temperature, i.e., the atmospheric temperature measured by the thermometer; Z (P,T) This refers to the compressibility factor of the outlet air at the constant flow rate orifice under actual conditions. It is dimensionless and refers to... Figure 2 As shown, this can be obtained by looking up a table.

[0063] S4. When testing the suction resistance standard rod, connect the suction resistance standard rod detection system, open the negative pressure air circuit and start timing. After 10 minutes, collect the pressure difference P3 between the atmosphere and the outlet of the suction resistance standard rod to be tested, measured by the differential pressure gauge; the absolute atmospheric pressure P2 measured by the atmospheric barometer; and the atmospheric temperature T measured by the thermometer. The pressure difference P3 is the suction resistance value PD of the suction resistance standard rod to be tested under the atmospheric temperature T and the absolute atmospheric pressure P2. Meas .

[0064] S5. The processing system uses the collected data to compare the resistance value of the suction resistance standard bar to be tested with the standard resistance value of the suction resistance standard bar of the specified specification. If the relative error is within 1%, it is considered qualified; otherwise, it is considered unqualified, so as to realize the periodic testing of the suction resistance standard bar.

[0065] When the processing system compares the collected suction resistance value with the suction resistance standard value, the atmospheric temperature T and atmospheric absolute pressure P2 actually affect the suction resistance value of the suction resistance standard bar. Therefore, the processing system will also correct the suction resistance value of the suction resistance standard bar to be tested according to the corresponding correction formula to ensure the accuracy of the periodic detection of the suction resistance standard bar.

[0066] For PD Meas Make corrections. The formula is as follows:

[0067] α=ΔT×(a1+a2×PD Meas )+ΔP atm ×(a3+a4×PD Meas )+a5×ΔRH+a6×(ΔP atm ) 2 ;

[0068]

[0069] Where: PD is the corrected absorption resistance value, in Pa; a is the correction factor under different temperature, humidity and atmospheric pressure conditions; PD Meas ΔT is the measured absorption resistance value, in mmWG; ΔT is the difference between the measured temperature and 22℃, in℃; ΔP atm The difference between measured atmospheric pressure and 101325 Pa is expressed in mmWG; ΔRH is expressed as the difference between measured relative humidity and 60%RH, expressed in %RH; a1 = -2.404 × 10⁻¹; a2 = -2.240 × 10⁻⁵; a3 = -2.891 × 10⁻³; a4 = -6.678 × 10⁻⁶; a5 = -2.707 × 10⁻³; a6 = 7.386 × 10⁻⁶.

[0070] The corrected suction resistance value PD is compared with the standard suction resistance value of the suction resistance standard bar to verify the suction resistance standard bar.

[0071] Example 2

[0072] See attached document Figure 3-5 A detection device for a constant flow orifice and a suction resistance standard bar includes a chassis 1 and a computer monitor 2 mounted on top of the chassis. The chassis 1 is equipped with a positive pressure gauge 3, a negative pressure gauge 4, a first switching switch 5, a detection switch 6, a suction resistance standard bar clamp 7, a constant flow orifice clamp 8, and a second switching switch 9. An atmospheric pressure gauge, a thermometer, and a mass flow meter 11 are mounted outside the chassis 1. The chassis 1 contains a constant flow orifice detection system and other components of the suction resistance standard bar detection system, such as a negative pressure generator, a constant flow orifice, a differential pressure gauge 10, a dryer, and a filter.

[0073] The system includes a positive pressure gauge 3 that connects to the externally introduced positive pressure gas (atmosphere) to display the atmospheric pressure and indicate whether the required pressure has been reached. A negative pressure generator connects to the externally introduced negative pressure gas, which generates negative pressure from the positive pressure and connects to a negative pressure gauge 4 to display the negative pressure value and indicate whether the required pressure has been reached. A first switching valve is controlled by a first switching switch 5. One end of the first switching valve is connected to the negative pressure generator, and the other end is switched via the first switching switch to connect to either the built-in constant flow orifice or the external constant flow orifice clamp, achieving interlocking of the gas paths of the constant flow orifice detection system and the suction resistance standard rod detection system. A detection switch 6 connects the compressed air to the negative pressure generator to generate negative pressure. The suction resistance standard rod clamp is connected to a filter via a T-joint and also to a differential pressure gauge 10, which can also be installed outside the chassis. One end of the differential pressure gauge is connected to a second switching valve, and the other end is connected to the outlet of the suction resistance standard rod clamp 7 or the inlet of the constant flow orifice clamp 8. The second switching valve is connected and switched via a second switching switch. The chassis serves as the main structural component of the entire monitoring equipment. A computer monitor is used for human-machine interaction. Preferably, both the suction resistance standard rod clamp 7 and the constant flow orifice clamp 8 are equipped with sealing rings to isolate them from the outside environment.

[0074] Furthermore, the compressed air is also connected to the negative pressure generator via a connecting valve, which is located at the rear of the chassis and controlled by a detection switch.

[0075] This invention enables periodic testing of constant flow orifices and suction resistance standard rods, eliminating the impact of deviations in the constant flow orifice or suction resistance standard rod during production. Furthermore, by incorporating a dryer to remove atmospheric moisture, it prevents damage to the constant flow orifice under test due to moisture ingress, ensuring the quality of the constant flow orifice. The inclusion of a filter further guarantees the quality of the constant flow orifice, preventing blockage during testing and ensuring the accuracy of the suction resistance standard rod test, thus improving testing results. Additionally, by installing sealing rings (made of rubber diaphragms) within the constant flow orifice and suction resistance standard rod clamps, it prevents airflow within these clamps while ensuring air circulation for both the suction resistance standard rod and the constant flow orifice.

[0076] Example 3

[0077] See attached document Figure 6-8 A constant flow orifice clamp is disclosed for installing a constant flow orifice in a constant flow orifice verification device. It includes a base 81 with a through hole, an upper pressure ring 82, and a top cover 83. A constant flow orifice 84 is disposed within the through hole of the base, upper pressure ring, and top cover. The top cover fits onto the base, and the upper pressure ring is located between the top cover and the base, abutting against both. An air inlet for the constant flow orifice clamp is formed at the end of the base away from the upper pressure ring, for connection to a dryer and a mass flow meter. An air outlet for the constant flow orifice clamp is formed at the end of the top cover away from the upper pressure ring, for connection to a negative pressure generator. Preferably, the base and top cover are pluggable, and at least one O-ring 86 is provided between the outer side of the base and the top cover to ensure the airtightness of the constant flow orifice clamp.

[0078] Furthermore, a rubber diaphragm 85 is provided in the through hole of the base, and the rubber diaphragm abuts against the end of the upper pressure ring. The upper pressure ring is connected to the base by threads, pressing the rubber diaphragm into the base. One end of the constant flow orifice passes through the rubber diaphragm, and the rubber diaphragm elastically seals one end of the constant flow orifice in the base, ensuring that the airflow only flows through the constant flow orifice.

[0079] Preferably, the constant flow orifice is perpendicular to the air inlet of the constant flow orifice clamp.

[0080] The present invention provides a constant flow orifice fixture, which can adapt to the verification and positioning of constant flow orifices of various specifications by setting a rubber diaphragm, and can ensure the airtightness of the constant flow orifice by setting an O-ring and a rubber diaphragm, thus providing a guarantee for the verification of constant flow orifices.

[0081] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A detection device for a constant flow orifice and a suction resistance standard bar, characterized in that, It includes a constant flow orifice period detection system for detecting constant flow orifices and a suction resistance standard bar period detection system for detecting suction resistance standard bars. The constant flow orifice period detection system and the suction resistance standard bar period detection system share a negative pressure generator, differential pressure gauge, thermometer, barometer and processing system. The constant flow orifice detection system includes a negative pressure generator, a constant flow orifice fixture for mounting the constant flow orifice to be detected, a dryer, a mass flow meter, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system. The negative pressure generator, the constant flow orifice fixture, the dryer, and the mass flow meter are arranged in sequence. The suction resistance standard bar detection system includes a negative pressure generator, a constant flow orifice, a filter, a suction resistance standard bar clamp for mounting the suction resistance standard bar, a differential pressure gauge, a thermometer, an atmospheric pressure gauge, and a processing system. The negative pressure generator, the constant flow orifice, the filter, and the suction resistance standard bar clamp are arranged in sequence. Both the suction resistance standard rod clamp and the constant flow orifice clamp are equipped with sealing rings. The negative pressure generator is connected to the constant flow orifice fixture and the constant flow orifice respectively through a three-way interface; When periodic testing of a constant flow orifice is required, the negative pressure generator is connected to the constant flow orifice fixture, and the differential pressure gauge is connected between the dryer and the constant flow orifice to be tested, for measuring the pressure difference between the constant flow orifice and the atmosphere. When periodic testing of a suction resistance standard rod is required, the negative pressure generator is connected to the constant flow orifice, and the differential pressure gauge is connected between the filter and the suction resistance standard rod fixture, for measuring the pressure difference between the suction resistance standard rod fixture and the atmosphere. The processing system is used to determine whether the flow rate of the constant flow orifice and the suction resistance value of the suction resistance standard rod meet the standards based on the pressure difference measured by the differential pressure gauge, the atmospheric temperature measured by the thermometer, and the atmospheric pressure measured by the barometer, thereby realizing periodic testing of the constant flow orifice or suction resistance standard rod.

2. The detection device for a constant flow orifice and a suction resistance standard bar according to claim 1, characterized in that, The sealing ring is a rubber diaphragm.

3. The detection device for a constant flow orifice and a suction resistance standard bar according to claim 1, characterized in that, The differential pressure gauge is connected between the dryer and the constant flow orifice clamp via a three-way interface, or between the filter and the suction resistance standard rod clamp.

4. A testing device for a constant flow orifice and a suction resistance standard bar, comprising the testing apparatus for a constant flow orifice and a suction resistance standard bar as described in any one of claims 1-3, characterized in that, It also includes the computer case and the computer monitor mounted on top of the case. The chassis is equipped with a detection switch, a first switching switch, a second switching switch, a suction resistance standard rod clamp, and a constant flow orifice clamp. The detection switch is used to connect the compressed air to the negative pressure generator to generate negative pressure. The first switching switch is connected to a first switching valve of the negative pressure generator at one end, and is used to control the connection switching of the other end of the first switching valve to connect the constant flow orifice or the constant flow orifice clamp. The second switching switch is connected to a second switching valve of the differential pressure gauge at one end, and is used to control the connection of the other end of the second switching valve between the suction resistance standard rod clamp and the filter, or between the constant flow orifice clamp and the dryer.

5. The detection device for a constant flow orifice and a suction resistance standard bar according to claim 4, characterized in that, The compressed air is also connected to the negative pressure generator via a connecting valve, which is located at the rear of the chassis and is controlled by a detection switch.

6. The detection device for a constant flow orifice and a suction resistance standard bar according to claim 4, characterized in that, The chassis is also equipped with a positive pressure gauge and a negative pressure gauge. The positive pressure gauge is connected to the introduced atmosphere and is used to display the pressure value of the positive pressure gas; the negative pressure gauge is connected to the introduced compressed air and is used to display the pressure value of the negative pressure gas.

7. A method for detecting a constant flow orifice and a suction resistance standard bar, implemented by a detection device for a constant flow orifice and a suction resistance standard bar as described in any one of claims 1-3, characterized in that, The specific steps are as follows: Step S1: When it is necessary to detect a constant flow orifice, connect the constant flow orifice detection system, collect the pressure difference P1 between the atmosphere and the constant flow orifice to be detected measured by the differential pressure gauge, the absolute atmospheric pressure P2 measured by the atmospheric pressure gauge, and calculate the inlet pressure P of the constant flow orifice to be detected. Step S2: Collect the atmospheric temperature T measured by the thermometer; Step S3: The processing system uses the data collected in steps S1 and S2 to calculate the flow rate Q of the constant flow orifice to be detected. （P,T） Determine the flow rate Q of the constant flow orifice to be tested. （P,T） Whether the constant flow rate orifice can be tested within the standard flow rate range of the tested specification; Step S4: When it is necessary to test the suction resistance standard rod, connect the suction resistance standard rod detection system, collect the pressure difference P3 between the atmosphere and the outlet of the suction resistance standard rod to be tested measured by the differential pressure gauge, the absolute atmospheric pressure P2 measured by the atmospheric pressure gauge, and the atmospheric temperature T measured by the thermometer. The pressure difference P3 is the suction resistance value of the suction resistance standard rod to be tested under the atmospheric temperature T and the absolute atmospheric pressure P2. Step S5: The processing system uses the data collected in step S4 to compare the resistance value of the suction resistance standard bar to be tested with the standard resistance value of the suction resistance standard bar of the specified specification, so as to realize the periodic detection of the suction resistance standard bar.

8. The method for detecting a constant flow orifice and a suction resistance standard bar according to claim 7, characterized in that, In step S3, the processing system uses the collected data to calculate the flow rate Q of the constant flow orifice. （P,T） The formula is: ； Among them, P N Atmospheric pressure under standard conditions; T N The temperature under standard conditions; Q N Z represents the flow rate under standard conditions. N Z represents the gas compressibility factor under standard conditions; P represents the inlet pressure of the constant flow orifice to be tested; T represents the air temperature at the inlet of the constant flow orifice to be tested under actual conditions, i.e., the atmospheric temperature measured by the thermometer; ... air temperature at the inlet pressure of the constant flow orifice to be tested. （P,T） The compressibility factor of the air outlet of a constant flow orifice fixture or constant flow orifice under actual conditions.

9. The method for detecting a constant flow orifice and a suction resistance standard bar according to claim 7, characterized in that, Step S5 also includes the processing system correcting the resistance value of the standard bar to be tested.

Images