CN104913886B - Method for leakage detection of Freon valve - Google Patents

Abstract

The invention provides a new method for leakage detection of a Freon valve, and belongs to the technical field of valve supervision and inspection. Freon is input via a Freon control vale firstly, high-temperature high-voltage water vapor is input via a high-temperature high-voltage stream control valve then, a mixed gas of the high-temperature high-voltage water vapor and the Freon enters a checked valve, multipoint step-by-step air extraction is performed on the checked valve by using an air extracting device, the extracted mixed gas is cooled in an air cooling device firstly, gas-liquid separation is performed in a gas-liquid separation device subsequently, and, finally, a halogen detector performs detection at air outlet of the gas-liquid separation device. The usage amount of the Freon is reduced, and serious pollution caused by that total fluoride as a working medium performs detection is reduced; a leakage point is accurately located through detection for the tracer gas Freon, and the leakage grade is determined through the number of lit alarm indicating lamps; and the cooling and gas-liquid separation devices are increased, an influence of too high stream temperature is prevented, and inspection precision is improved.

Description

Freon valve leak detection method

technical field

The invention belongs to the technical field of valve supervision and inspection, and in particular uses freon as a tracer gas to detect valve leakage points and determine leakage levels.

Background technique

At present, the valve leak detection methods mainly include: bubble leak detection method, halogen leak detection method, pressure drop leak detection method, sensor flow detection method, helium gas spectral analysis detection method and ultrasonic leak detection method. Although the traditional air bubble leak detection method can detect the leakage, it cannot measure the leakage amount. Although the improved gas collection method can measure the leakage amount, the accuracy is not enough, and the implementation limitations are very large. The pressure drop leak detection method can indirectly calculate the leakage rate, but it is difficult to detect small leaks due to detection and accuracy reasons, and the implementation efficiency in general industrial sites is low. The sensor flow detection method can directly detect the leakage rate, but the accuracy of the instrument required for micro-leakage measurement is very high, resulting in high detection costs, which is difficult to achieve in general industrial sites. The helium spectroscopic analysis detection method is mainly used to detect micro-leakage. The leak detection sensitivity is high, but it needs to create a vacuum environment, and the entire detection process takes a long time. Moreover, helium is expensive, and the detection cost is high, so the utilization rate in valve enterprises is low. The ultrasonic leak detection method can quickly locate the leak point, takes a short time, and has high leak detection accuracy. However, the development of ultrasonic leak detection equipment is difficult. At present, ultrasonic leak detectors at home and abroad can only make qualitative judgments and cannot calculate the amount of leakage. . The traditional halogen detection method uses a large amount of freon, which is easy to cause great pollution to the environment.

Contents of the invention

The purpose of the present invention is to improve the traditional perfluorinated leak detection method, while reducing the amount of halogen used, reduce the serious pollution of the environment caused by the traditional halogen detection method, accurately detect the micro-leakage point and determine the leakage level, and improve the safety of the industrial site. Valve air tightness leak detection efficiency.

Technical scheme of the present invention:

A new method for leak detection of freon valves. The detection system used in this method includes the inspected valve, high temperature and high pressure steam control valve 1, freon storage container 2, freon control valve 3, steam exhaust valve 4, air extraction device 5, air cooling device 6, Condensed water control valve 7, gas-liquid separation device 8 and halogen detector 9; high-temperature and high-pressure steam control valve 1 is installed at the inlet of the high-temperature and high-pressure steam pipeline, and the middle part of the high-temperature and high-pressure steam pipeline is connected with Freon storage container 2, and the outlet of Freon storage container 2 Freon control valve 3 is installed at the place where the inspected valve is connected with the high-temperature and high-pressure steam inlet pipe and the exhaust steam pipe. The connection mode is determined by the structure of the inspected valve. The distance between the front end of the gas device 5 and the detection point on the surface of the tested valve is not more than 3mm, and the air cooling device 6 is integrated with the air extraction device 5, and the air flows through the air cooling device 6 to fully cool the gas pumped by the air extraction device 5 , the gas-liquid separation device 8 is installed at the end of the air extraction device 5, the condensate control valve 7 is installed at the bottom of the gas-liquid separation device 8, the probe of the halogen detector 9 is close to the lower edge of the gas outlet of the gas-liquid separation device 8, and the probe is connected to the outlet The horizontal distance of the gas port is not more than 3mm.

A new method for leak detection of Freon valves. On the basis of the traditional detection of all Freon working fluids, a new detection method is proposed in which high-temperature and high-pressure water vapor carries Freon as a working medium. The concentration ratio of Freon to high-temperature and high-pressure water vapor is 1:10. Increase the pressure of the inspection medium, reduce the pollution to the environment, accurately detect the micro-leakage point of the inspected valve, and grade the leakage of the inspected valve. Device 6 and gas-liquid separation device 8. Utilizing the principle that freon can be used as tracer particles, freon is first introduced into freon through freon control valve 3, and then high-temperature and high-pressure steam is introduced through high-temperature and high-pressure steam control valve 1. The concentration ratio of freon to high-temperature and high-pressure water vapor is 1:10. The mixed gas of water vapor and freon enters the valve under test, and the surface of the valve under test is pumped at multiple points by using the air extraction device 5, and the extracted mixed gas enters the air cooling device 6 for cooling, and the water vapor in the mixed gas condenses into a liquid state Water, then liquid water and freon enter the gas-liquid separation device 8, wherein the liquid water is discharged through the condensate control valve 7, and the halogen detector 9 conducts final qualitative detection at the gas outlet of the gas-liquid separation device 8 and determines the leakage level.

The effects and benefits of the present invention are: the mode of using high-temperature and high-pressure water vapor to carry Freon tracer gas, the concentration ratio of Freon to high-temperature and high-pressure water vapor is 1:10, which increases the pressure of the inspection working medium and can detect smaller leaks points; three-dimensional multi-point step-by-step pumping is carried out on the surface of the valve to ensure the detection accuracy; the use of freon is reduced compared with the previous perfluorinated detection, and the serious pollution caused by the use of freon gas for detection is reduced; through the tracer While detecting the gas freon to accurately locate the leak point, study the relationship between the tracer gas concentration and the valve leakage level, and then determine the leakage level; increase the cooling device and the gas-liquid separation device to avoid the detection due to excessive steam temperature The impact of the instrument detection accuracy.

Description of drawings

Accompanying drawing 1 is a schematic diagram of the overall detection process of the new method for leak detection of Freon valves of the present invention.

In Fig. 1: 1 high temperature and high pressure steam control valve; 2 freon storage container; 3 freon control valve; 4 steam exhaust valve; 5 air extraction device; 6 air cooling device; 7 condensate water control valve; Detector.

detailed description

The specific embodiments of the present invention will be described in detail below in conjunction with the technical solutions and accompanying drawings.

The working process of the present invention is as follows: arrange according to the schematic diagram of the device, align the probe of the halogen detector 9 with the outlet of the gas-liquid separation device 8, and because the gas density of Freon is higher than that of air, the probe of the halogen detector 9 should be close to the gas-liquid separation device 8 The lower edge of the gas outlet, the horizontal distance between the probe of the halogen detector 9 and the gas outlet of the gas-liquid separation device 8 is not more than 3mm. Open the high-temperature and high-pressure steam control valve 1, the exhaust steam valve 4 and the inspected valve, and close the Freon control valve 3 at the same time, and pass the high-temperature and high-pressure steam into the high-temperature and high-pressure steam pipeline to exhaust the air in the device. Then close the high-temperature and high-pressure steam control valve 1. After the pressure in the device returns to normal, close the tested valve and the steam exhaust valve 4, open the Freon control valve 3, and close the Freon control valve 3 after the Freon is introduced. Then, open the high-temperature and high-pressure steam control valve 1, and introduce high-temperature and high-pressure steam. The concentration ratio of Freon and high-temperature and high-pressure steam is 1:10. 5. Perform multi-point and step-by-step pumping on the surface of the tested valve. The front end of the pumping device 5 must not be removed immediately. After staying for 3 seconds, move slowly, and the distance from the surface detection point of the tested valve is not greater than 3mm. If the valve under test leaks, the extracted gas is a mixture of high-temperature water vapor and Freon. Subsequently, the mixed gas is cooled by circulating air in the air cooling device 6, in which the water vapor is condensed into liquid water, and then the liquid water and Freon enter the gas-liquid separation device 8, and the liquid water is discharged by the condensate control valve 7, from the gas-liquid separation The freon discharged from the outlet of the device 8 is pumped into the halogen detector 9 for detection, the halogen detector 9 beeps, and the leakage is rated according to the number of the alarm indicators on the halogen detector 9, and the ITE-5650A- Taking the FP type halogen leak detector as an example, it is divided into one to seven levels, that is, the leakage amount is the most when the alarm indicator light is on seven, which is defined as seven levels of leakage. If the tested valve does not leak, the alarm indicator light of the halogen leak detector 9 will flash at the original frequency, and the buzzer will not sound.

Claims (1)

1. A Freon valve leak detection method, characterized in that the detection system used in the method comprises a valve under inspection, a high temperature and high pressure steam control valve, a Freon storage container, a Freon control valve, a steam exhaust valve, an air extraction device, and an air cooling device , condensed water control valve, gas-liquid separation device and halogen detector; install a high-temperature and high-pressure steam control valve at the inlet of the high-temperature and high-pressure steam pipeline, connect the middle part of the high-temperature and high-pressure steam pipeline with the Freon storage container, and install a Freon control valve at the outlet of the Freon storage container , the inspected valve is connected with the high-temperature and high-pressure steam inlet pipe and the steam exhaust pipe. The connection method is determined by the structure of the inspected valve. The distance between the surface detection points is not more than 3mm. The air cooling device is integrated with the air extraction device. The air flows through the air cooling device to fully cool the gas pumped in the air extraction device. The gas-liquid separation device is installed at the end of the air extraction device. , a condensate control valve is installed at the bottom of the gas-liquid separation device, the probe of the halogen detector is close to the lower edge of the gas outlet of the gas-liquid separation device, and the horizontal distance between the probe and the gas outlet is not more than 3mm; the Freon is high-temperature chemically stable Freon, the specific method is as follows: Using Freon as a tracer particle, the Freon control valve is first introduced into Freon, and then the high-temperature and high-pressure steam control valve is introduced into high-temperature and high-pressure steam. The mixed gas enters the tested valve, and the surface of the tested valve is pumped at multiple points by using the pumping device. The extracted mixed gas enters the air cooling device for cooling. The water vapor in the mixed gas condenses into liquid water, and then the liquid water and Freon Enter the gas-liquid separation device, where the liquid water is discharged through the condensate control valve, and the halogen detector performs the final qualitative detection at the gas outlet of the gas-liquid separation device to determine the leakage level.