CN113310643A - Leakage detection device and method for single pipe in tubular heat exchanger - Google Patents
Leakage detection device and method for single pipe in tubular heat exchanger Download PDFInfo
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- CN113310643A CN113310643A CN202110755793.8A CN202110755793A CN113310643A CN 113310643 A CN113310643 A CN 113310643A CN 202110755793 A CN202110755793 A CN 202110755793A CN 113310643 A CN113310643 A CN 113310643A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
- G01M3/3227—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators for radiators
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
- G01M3/3236—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators by monitoring the interior space of the containers
- G01M3/3272—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators by monitoring the interior space of the containers for verifying the internal pressure of closed containers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
- G01M3/34—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators by testing the possibility of maintaining the vacuum in containers, e.g. in can-testing machines
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Abstract
The invention provides a leakage detection device and a leakage detection method for a single pipe in a tubular heat exchanger, wherein the leakage detection device comprises a single pipe sealing assembly and a vacuumizing assembly, the single pipe sealing assembly is used for sealing the single pipe to be detected in the tubular heat exchanger, and the vacuumizing end of the vacuumizing assembly is hermetically connected with the single pipe sealing assembly; the single-pipe sealing assembly comprises a vacuum cap and an exhaust cap, the vacuum cap is in a cap shape with a first end closed and a second end opened, the size of the opening end of the vacuum cap is not smaller than the size of a pipe orifice welding line/expansion opening of a single pipe in the pipe heat exchanger to be vacuumized, and the opening end of the vacuum cap is used for being tightly closed and attached to the pipe orifice part of the single pipe in the pipe heat exchanger to be vacuumized; the air extraction cap is in a cap shape: the first end is used for the air exhaust pipe of sealing connection, and the second end is used for closely sealing the laminating with the oral area of the single pipe in the tubular heat exchanger of treating the evacuation.
Description
Technical Field
The invention relates to the technical field of energy industrial equipment detection, in particular to a leakage detection device and a leakage detection method for a single pipe of a tubular heat exchanger of a generator in energy industrial equipment.
Background
In the energy industry, particularly on a turbo generator and high-voltage motor equipment, a tubular heat exchanger system exists, leakage is easily caused by corrosion, abrasion and the like in the tubular heat exchanger system, the integral safe operation of a generator set is seriously threatened, and the production of enterprises is influenced.
The current tubular heat exchanger commonly used mainly has categories such as spring winding type, winding piece type, extrusion piece type and threading piece type, and the conventional leak hunting mode after the tubular heat exchanger takes place to leak is: and (4) carrying out integral airtight leakage detection, and carrying out single water pressure, airtight, vacuum pumping or eddy current flaw detection leakage detection if leakage is found.
1) The whole water pressure leak hunting can only find the pipeline leakage which is located on the surface layer of the heat exchanger and faces outwards, the leakage points of the surface layer and the inner layer heat exchange pipeline are difficult to observe, and the specific position of the internal leakage pipeline cannot be determined.
2) The hydraulic leakage detection of a single heat exchange tube needs to be made with a special clamp so as to ensure reliable sealing between the leakage detection device and a tube bearing plate, the device is relatively heavy, a plurality of persons (more than 4 persons) are needed to cooperate to perform leakage detection operation, a water source and a power source are needed, the device is relatively heavy, the leakage detection efficiency is low, and the clamp is difficult to be made for heat exchangers (such as condensers) with large volumes.
3) The problems of air-tight leakage detection and water pressure leakage detection are similar, and because the gas compression amount is very large, the pressure reduction is not obvious when leakage occurs; meanwhile, the leakage point is difficult to distinguish by naked eyes, the leakage is detected by a special instrument after the soap solution is coated or the whole body is soaked or the tracer gas (such as halide gas) is injected after the gas is filled, the operation is relatively complex, and the leakage detection difficulty of a large heat exchanger is higher.
4) The eddy current flaw detection and leakage detection are only suitable for the tubular heat exchanger with a regular shape, the flaw detection and leakage detection are difficult to perform for the heat exchange tube with a special shape or a small inner diameter, the overall cost is high, and the leakage detection precision for the leakage points at the expansion ports (or welding seams) at the two ends of the heat exchange tube is insufficient.
5) The current technology for vacuum-pumping leakage detection is a vacuum gun leakage detection method, wherein 1 piece (or two pieces) of main vacuum guns and 1 piece (or two main vacuum guns) of auxiliary vacuum guns are required simultaneously during leakage detection, and the main vacuum guns and the auxiliary vacuum guns are inserted into a heat exchange pipe to be detected through a vacuum-pumping nozzle at the front end of a gun head. When in operation, 3-4 persons (two persons at the main gun side and one person at the auxiliary gun side) are required to operate simultaneously, and the piston in the gun is pulled manually to vacuumize. Although the method improves the efficiency compared with a single water pressure and airtight method, the equipment is still relatively heavy, the leakage detection result is greatly influenced due to the limited matching airtightness of the piston system and the vacuumizing nozzle, meanwhile, the leakage point outside the pipe orifice of the single heat exchange pipe cannot be judged, and the leakage detection accuracy is limited.
The conventional single-tube leakage detecting mode of the tube heat exchanger has the problems of difficult leakage point positioning, water source power supply requirement, relatively heavy device, low working efficiency and limited leakage detecting accuracy.
How to solve the above difficulties is a problem to be solved.
Disclosure of Invention
In order to solve the technical problem, the invention provides a leakage detection device and a leakage detection method for a single pipe in a tubular heat exchanger.
A leak detection device for a single tube in a tube heat exchanger, wherein: the single-tube heat exchanger comprises a single-tube sealing assembly and a vacuumizing assembly, wherein the single-tube sealing assembly is used for sealing a single tube to be detected in the tube heat exchanger, and a vacuumizing end of the vacuumizing assembly is hermetically connected with the single-tube sealing assembly.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: the single-pipe sealing assembly comprises a vacuum cap and an exhaust cap, the vacuum cap is in a cap shape with a first end closed and a second end opened, the size of the opening end of the vacuum cap is not smaller than the size of a pipe orifice welding line/expansion opening of a single pipe in the pipe heat exchanger to be vacuumized, and the opening end of the vacuum cap is used for being tightly closed and attached to the pipe orifice part of the single pipe in the pipe heat exchanger to be vacuumized; the air extraction cap is in a cap shape: the first end is used for being hermetically connected with the exhaust tube, and the open end of the second end is used for being closely and closely attached to the tube orifice of a single tube in the tube heat exchanger to be vacuumized; the size of the opening end of the extraction cap is not less than the size of the pipe orifice welding seam/expansion pipe orifice of a single pipe in the tubular heat exchanger to be vacuumized.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: an annular plane sealing gasket is arranged at the opening end of the vacuum cap, and the outer diameter size of the annular plane sealing gasket is larger than the size of a pipe orifice of a single pipe in the tubular heat exchanger to be vacuumized; the opening end of the pumping cap is provided with an annular plane sealing gasket, and the outer diameter size of the annular plane sealing gasket is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: the inner diameter size of the annular plane sealing gasket at the opening end of the vacuum cap is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized; the inner diameter size of the annular plane sealing gasket at the opening end of the pumping cap is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: a coupling agent capable of generating bubbles is also coated between the annular plane sealing gasket at the opening end of the vacuum cap and the end tube plate of the heat exchange tube to be detected; and a coupling agent capable of generating bubbles is also coated between the annular plane sealing gasket at the opening end of the suction cap and the end pipe plate of the heat exchange pipe to be detected.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: the coupling agent is a detergent with viscosity and foaming functions.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: the vacuumizing assembly comprises an exhaust pipe, a leakage detection vacuum pressure gauge, a vacuum breaking valve, a vacuum valve and a vacuum pump, wherein the exhaust end of the exhaust pipe is hermetically connected to the first end of an exhaust cap, and the leakage detection vacuum pressure gauge, the vacuum breaking valve, the vacuum valve and the vacuum pump are sequentially arranged on the exhaust pipe from behind the exhaust cap.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: the vacuum pumping assembly further comprises an air filter screen, and the air filter screen is arranged between the vacuum valve and the vacuum pump on the exhaust pipe.
Further, the device that leaks hunting to single pipe in tubular heat exchanger, wherein: the vacuum pumping assembly further comprises a vacuum pump vacuum pressure gauge, and the vacuum pump vacuum pressure gauge is arranged between the air filter screen and the vacuum pump on the exhaust pipe.
A leakage detection method for a single-pipe leakage detection device in a tubular heat exchanger comprises the following steps:
(1) preparing a tube plate: after the tubular heat exchanger is disassembled, cleaning tube plates at two ends of the tubular heat exchanger until the original metal surface is exposed or the coupled hard scale/corrosion surface is not influenced;
(2) preparation before air extraction: coating coupling agents on tube plates and tube openings at two ends of a single heat exchange tube to be detected in a tube heat exchanger, respectively fastening opening ends of an air extracting cap and a vacuum cap outside an air extracting end and a vacuum sealing end in the tube openings at the two ends, ensuring that the air extracting cap and the vacuum cap can completely and hermetically cover a welding or expansion opening part of the heat exchange tube to be detected on the tube plates, matching annular plane sealing gaskets at the opening ends of the air extracting cap and the vacuum cap with tube plate planes around the tube openings to be detected, pressing, and ensuring that a joint surface is tightly attached;
(3) air extraction: opening a vacuum valve, opening a vacuum pump, pumping air in a heat exchange tube to be detected to a vacuum pump through an exhaust tube, the vacuum valve and a filter screen connected to an exhaust cap, discharging the air, pumping the air until negative pressure is generated in the heat exchange tube, enabling the exhaust cap and the vacuum cap to be self-absorbed on a tube plate, closing the vacuum pump and the vacuum valve when the gauge pressure of a vacuum pressure gauge to be detected to leak is reduced to below-600 mmHg/-80kPa, continuously observing for about 10 seconds, judging that the heat exchange tube has no leak point if the vacuum is not obviously reduced, and otherwise, proving that the heat exchange tube has leakage if the vacuum cannot be maintained;
(4) tube replacement: and opening the vacuum breaking valve, recovering the normal pressure, and then removing the air exhaust cap and the vacuum cap to change to the next heat exchange tube to be detected.
The leakage detection device and the leakage detection method for the single pipe in the tubular heat exchanger have the advantages that the leakage detection accuracy is high, clamps and lifting appliances are not needed, water sources and power supplies are not needed, the vacuum cap and the air extraction cap which are made of transparent materials are used, and the leakage of a welding line or an expansion opening of a pipe orifice of a heat exchange pipe can be relatively visually observed; the air exhaust pipe between the air exhaust cap and the air exhaust device is a hose, so that the operation is easy and convenient; by using the rechargeable oil-free diaphragm vacuum pump, the structure is simple, the weight is light and portable, 1-2 people such as a U-shaped tubular heat exchanger only need 1 person under the conditions that the viscosity of the coupling agent is good and the sealing effect of the annular plane sealing gasket is good, and the operation can be easily performed by 1 person at each of two ends of the linear tubular heat exchanger. The practical verification proves that the efficiency of the scheme is improved by 8-10 times compared with that of a hydraulic single leakage detection method, and the efficiency is also obviously improved compared with that of a gun type vacuum leakage detection method.
Drawings
FIG. 1 is a schematic view showing the connection of a suction cap and a vacuum cap of a leak detection device for a single pipe in a tubular heat exchanger according to the present invention to the single pipe in the tubular heat exchanger;
figure 2 is an overall schematic diagram of the leak detection device of the present invention.
Detailed Description
The invention provides a leakage detection device for a single pipe in a tubular heat exchanger, which comprises a single pipe sealing assembly and a vacuumizing assembly, wherein the single pipe sealing assembly is used for sealing the single pipe to be detected in the tubular heat exchanger, and the vacuumizing end of the vacuumizing assembly is hermetically connected with the single pipe sealing assembly.
The single-pipe sealing assembly comprises a vacuum cap and an exhaust cap, the vacuum cap is in a cap shape with a first end closed and a second end opened, the size of the opening end of the vacuum cap is not smaller than the size of a pipe orifice welding line/expansion opening of a single pipe in the pipe heat exchanger to be vacuumized, and the opening end of the vacuum cap is used for being tightly closed and attached to the pipe orifice part of the single pipe in the pipe heat exchanger to be vacuumized; the air extraction cap is in a cap shape: the first end is used for being hermetically connected with the exhaust tube, and the open end of the second end is used for being closely and closely attached to the tube orifice of a single tube in the tube heat exchanger to be vacuumized; the size of the opening end of the extraction cap is not less than the size of the pipe orifice welding seam/expansion pipe orifice of a single pipe in the tubular heat exchanger to be vacuumized.
An annular plane sealing gasket is arranged at the opening end of the vacuum cap, and the outer diameter size of the annular plane sealing gasket is larger than the size of a pipe orifice of a single pipe in the tubular heat exchanger to be vacuumized; the opening end of the pumping cap is provided with an annular plane sealing gasket, and the outer diameter size of the annular plane sealing gasket is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized.
A coupling agent capable of generating bubbles is also coated between the annular plane sealing gasket at the opening end of the vacuum cap and the end tube plate of the heat exchange tube to be detected; and a coupling agent capable of generating bubbles is also coated between the annular plane sealing gasket at the opening end of the suction cap and the end pipe plate of the heat exchange pipe to be detected.
The coupling agent is a detergent with viscosity and foaming function, such as laundry detergent, bath foam, etc.
The vacuumizing assembly comprises an exhaust pipe, a leakage detection vacuum pressure gauge, a vacuum breaking valve, a vacuum valve and a vacuum pump, wherein the exhaust end of the exhaust pipe is hermetically connected to the first end of an exhaust cap, and the leakage detection vacuum pressure gauge, the vacuum breaking valve, the vacuum valve and the vacuum pump are sequentially arranged on the exhaust pipe from behind the exhaust cap.
The vacuum pumping assembly further comprises an air filter screen, and the air filter screen is arranged between the vacuum valve and the vacuum pump on the exhaust pipe.
The vacuum pumping assembly further comprises a vacuum pump vacuum pressure gauge, and the vacuum pump vacuum pressure gauge is arranged between the air filter screen and the vacuum pump on the exhaust pipe.
Fig. 1 is a schematic view showing a connection of an extraction cap and a vacuum cap in a leak detection device for a single tube in a tube heat exchanger according to the present invention on the single tube in the tube heat exchanger, wherein a plurality of heat exchange tubes are arranged between a tube sheet a with a reference number 3 and a tube sheet b with a reference number 5 in fig. 1, and a single heat exchange tube 4 to be tested in the figure is taken as an example for explanation: the vacuum cap 1 is buckled outside a welding seam/expansion port 2 of a heat exchange tube 4 on the outer side of a tube plate a through an annular plane sealing gasket 9, the air exhaust cap 7 is buckled outside the welding seam/expansion port of the heat exchange tube 4 on the outer side of a tube plate b through an annular plane sealing gasket 6, an air exhaust nozzle 8 is arranged on the air exhaust cap 7, the air exhaust nozzle 8 is used for being connected with the air exhaust tube in a sealing mode, and the arrow points to the air exhaust direction.
Fig. 2 shows a schematic diagram of a single leakage checking device according to the present invention, after two ends of a heat exchange tube 4 are respectively connected to a vacuum cap 1 and an air extraction cap 7 in a sealing manner, an air extraction end of an air extraction tube 18 is connected to an air extraction nozzle 8 of the air extraction cap 7 in a sealing manner, an arrow points to an air extraction direction, a leakage checking vacuum pressure gauge 12 and a vacuum breaker valve 17 are sequentially arranged on the air extraction tube 18 from the air extraction end, an air filter screen 16 is connected to the air extraction tube 18 after being connected to a vacuum valve 13 in series, a vacuum pump vacuum pressure gauge 14 and a vacuum pump 15 are sequentially arranged on the air extraction tube 18 after the air filter screen 16, and air extracted from the air extraction cap 7 is exhausted through the vacuum pump 15.
The invention also provides a leakage detection method for the single-pipe leakage detection device in the tubular heat exchanger, which specifically comprises the following steps:
(1) preparing a tube plate: after the tube type heat exchanger is disassembled, tube plates 3 and 5 at two ends of the tube type heat exchanger are cleaned until the original metal surface is exposed or the coupled hard scale/rust surface is not influenced;
(2) preparation before air extraction: the method comprises the following steps of coating couplants on tube plates 3 and 5 and a tube opening 2 at two ends of a single heat exchange tube 4 to be detected in a tubular heat exchanger, respectively buckling opening ends of an air extracting cap 7 and a vacuum cap 1 outside an air extracting end and a vacuum sealing end in the tube openings at the two ends, ensuring that the air extracting cap 7 and the vacuum cap 1 can completely cover welding or expanding openings 2 of the heat exchange tube 4 to be detected on the tube plates 3 and 5 in a sealing manner, respectively matching annular plane sealing gaskets 6 and 9 at the opening ends of the air extracting cap 7 and the vacuum cap 1 with planes of the tube plates 5 and 3 around the tube opening to be detected, pressing, and ensuring that a joint surface is tightly attached;
(3) air extraction: the vacuum valve 13 is opened, the vacuum pump 15 is opened, the air in the heat exchange tube 4 to be detected is pumped to the vacuum pump 15 through the air pumping tube 18 and the vacuum valve 13 which are connected on the air pumping cap 7 and then is discharged, the air pumping cap 7 and the vacuum cap 1 can be self-sucked on the tube plates 3 and 5 after being pumped to the heat exchange tube 4 to generate negative pressure, when the gauge pressure of the vacuum pressure gauge 12 to be detected is reduced to be below-600 mmHg/-80kPa, the vacuum pump 15 and the vacuum valve 13 are closed, and the continuous observation time is not less than 10 seconds: if the vacuum does not drop obviously, the heat exchange tube 4 can be judged to have no leakage point, otherwise, if the vacuum can not be maintained, the heat exchange tube 4 is proved to have leakage;
(4) tube replacement: and opening the vacuum breaking valve 17, removing the air exhaust cap 7 and the vacuum cap 1 after the normal pressure is recovered, and switching to the next heat exchange tube to be detected.
The technical scheme of the invention has novel design, does not need clamps, lifting appliances, water sources and power supplies, uses the vacuum cap and the air extraction cap made of transparent materials, and can relatively visually observe whether the pipe orifice (welding line or expansion port) of the heat exchange pipe is leaked or not; the air exhaust pipe between the air exhaust cap and the air exhaust device is a hose, so that the operation is easy and convenient; the rechargeable oil-free diaphragm vacuum pump is simple in structure, light and portable, and can be easily operated by a single person; the matching personnel only need to synchronously place the vacuum cap on the opposite pipe orifice without other operations; under the conditions of good coupling agent viscosity and good sealing effect of the annular plane sealing gasket, the operation can be easily carried out by 1-2 persons (only 1 person is needed for the U-shaped tube type heat exchanger, and 1 person is needed for each of two ends of the linear tube type heat exchanger).
According to practical verification, the efficiency of the method is improved by 8-10 times compared with that of a hydraulic single-pressure leak detection method, and the efficiency is also obviously improved compared with that of a gun type vacuum leak detection method; and a vacuum valve and a coupling agent are used, so that misjudgment caused by the self reason of the device is avoided, and the leak detection accuracy is high.
The device has good air tightness, and in order to ensure reliability, the device system needs to be checked and subjected to vacuum test before use, so that the leakage of the device system is prevented from influencing the field judgment.
The coupling agent needs to use soap solution, laundry detergent and the like with certain viscosity so as to play a dual role of coupling surfaces and foaming in case of air leakage.
The transparent cap type (vacuum cap and extraction cap) vacuum leakage detection technology for the single heat exchange tube of the tubular heat exchanger can visually observe the air leakage condition of the joint surface of the tube plate.
The hose connection between exhaust cap and the leak detection device host computer, the convenient flexibility of leak detection adapts to narrow and small space, need not heavy instrument and lifts by crane equipment.
When a single heat exchange tube is used for leakage detection, the opposite side of the air pumping cap is sealed by a transparent vacuum cap, so that the operation is light and easy.
The annular plane sealing gasket used on the joint surface of the vacuum cap and the air exhaust cap is a silicon rubber sealing gasket matched with a viscous soap liquid coupling agent, and has the advantages of simple structure, aging resistance and tight attachment.
The viscous detergent is used as the coupling agent, so that the tight combination is ensured, air leakage is avoided, bubbles are formed when leakage occurs, and the observation is facilitated.
The leak detection device integrates a vacuum pump, a vacuum pressure gauge, a vacuum valve, a vacuum breaker valve and the like into a whole, and is convenient to operate.
The host machine of the leakage detection device adopts a rechargeable oil-free vacuum pump, does not need an external power supply and is portable and maintenance-free.
The inlet of the vacuum pump adopts an air filter element, so that the damage to the vacuum pump caused by the suction of foreign matters is prevented.
A vacuum valve is further adopted before the air filter element at the inlet of the vacuum pump, so that the test effect is not influenced by the tightness problem of the vacuum pump of the main machine during the test.
A vacuum breaker valve is arranged in front of the vacuum valve, so that pressure relief is ensured in time after the test of each heat exchange tube is finished, and the problems that the hard pulling of a vacuum cap and an air extraction cap in a negative pressure state wastes time and energy and foreign matters are sucked from a joint surface are prevented.
In addition to the above embodiments, the negative pressure (vacuum) can be generated by various means as follows:
(1) negative pressure (vacuum) is achieved using a vacuum pump driven by an engine or other power source.
(2) The negative pressure (vacuum) is realized by using an electric vacuum pump which needs an external power supply.
(3) The negative pressure (vacuum) is realized by using a vacuum suction ball with elasticity.
(4) Negative pressure (vacuum) is realized through the chemical reaction of gas in the single heat exchange tube.
Common points are as follows: a negative pressure (vacuum) is formed in the pipe to be checked for leaks.
Realize the multiple connected mode between air exhaust device and the heat exchanger:
(1) the interfaces made of other elastic materials are used for replacing the silica gel sealing rings to realize the sealing among the vacuum cap, the air exhaust cap and the tube plate.
(2) The interfaces with other shapes are used for replacing the plane sealing rings to realize the sealing between the vacuum cap, the suction cap and the tube plate.
(3) Other types of couplants are used instead of viscous soap to effect a seal between the vacuum cap, suction cap and tube sheet.
Common points are as follows: reliable sealing among the vacuum cap, the exhaust cap and the tube plate is realized.
Various modes of a negative pressure (vacuum) system formed at two ends of a single heat exchange tube:
(1) the vacuum cap and the air extraction cap are made of different materials to form an observable negative pressure (vacuum) system.
(2) The heat exchange pipe orifice sealing and air exhaust transition elements with different shapes and sizes are adopted to form an observable negative pressure (vacuum) system.
Common points are as follows: creating an observable negative pressure (vacuum) system.
The negative pressure (vacuum) reduction rate can also be judged in different ways, such as an electric contact vacuum pressure gauge, a digital vacuum pressure probe and a corresponding automatic judgment circuit.
The device host with different shapes, sizes, structures and materials is adopted, and the functions are to manufacture negative pressure (vacuum) and can be observed and sealed.
In addition to this, it is also possible:
(1) the negative pressure (vacuum) is realized by using pneumatic, engine-driven, external power supply type electric vacuum pump or elastic vacuum suction ball or chemical reaction.
(2) The vacuum cap, the exhaust cap and the tube plate are sealed by using interfaces made of other materials and in other shapes to replace a silica gel plane sealing ring.
(3) Other types of couplants are used instead of viscous detergents to achieve a seal between the vacuum cap, suction cap and tubesheet.
(4) The host of the leak detection device is made of materials with different shapes, sizes and structures.
(5) The vacuum drop rate is determined in different ways (e.g., by an electrometric gauge and corresponding automatic determination circuit).
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. The utility model provides a to device of looking for leaks of single pipe in tubular heat exchanger which characterized in that: the single-tube heat exchanger comprises a single-tube sealing assembly and a vacuumizing assembly, wherein the single-tube sealing assembly is used for sealing a single tube to be detected in the tube heat exchanger, and a vacuumizing end of the vacuumizing assembly is hermetically connected with the single-tube sealing assembly.
2. A leak detector as claimed in claim 1 for a single tube in a tube heat exchanger, wherein: the single-pipe sealing assembly comprises a vacuum cap and an exhaust cap, the vacuum cap is in a cap shape with a first end closed and a second end opened, the size of the opening end of the vacuum cap is not smaller than the size of a pipe orifice welding line/expansion opening of a single pipe in the pipe heat exchanger to be vacuumized, and the opening end of the vacuum cap is used for being tightly closed and attached to the pipe orifice part of the single pipe in the pipe heat exchanger to be vacuumized; the air extraction cap is in a cap shape: the first end is used for being hermetically connected with the exhaust tube, and the open end of the second end is used for being closely and closely attached to the tube orifice of a single tube in the tube heat exchanger to be vacuumized; the size of the opening end of the extraction cap is not less than the size of the pipe orifice welding seam/expansion pipe orifice of a single pipe in the tubular heat exchanger to be vacuumized.
3. A leak detector as claimed in claim 2 for a single tube in a tube heat exchanger, wherein: an annular plane sealing gasket is arranged at the opening end of the vacuum cap, and the outer diameter size of the annular plane sealing gasket is larger than the size of a pipe orifice of a single pipe in the tubular heat exchanger to be vacuumized; the opening end of the pumping cap is provided with an annular plane sealing gasket, and the outer diameter size of the annular plane sealing gasket is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized.
4. A leak detection device for a single tube in a tube heat exchanger as set forth in claim 3, wherein: the inner diameter size of the annular plane sealing gasket at the opening end of the vacuum cap is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized; the inner diameter size of the annular plane sealing gasket at the opening end of the pumping cap is larger than the pipe orifice size of a single pipe in the tubular heat exchanger to be vacuumized.
5. The leak detection device for a single tube in a tube heat exchanger as set forth in claim 4, wherein: a coupling agent capable of generating bubbles is also coated between the annular plane sealing gasket at the opening end of the vacuum cap and the end tube plate of the heat exchange tube to be detected; and a coupling agent capable of generating bubbles is also coated between the annular plane sealing gasket at the opening end of the suction cap and the end pipe plate of the heat exchange pipe to be detected.
6. A leak detection device for a single tube in a tube heat exchanger as set forth in claim 5, wherein: the coupling agent is a detergent with viscosity and foaming functions.
7. A leak detection device for a single tube in a tube heat exchanger according to claim 2 or 3 or 4, wherein: the vacuumizing assembly comprises an exhaust pipe, a leakage detection vacuum pressure gauge, a vacuum breaking valve, a vacuum valve and a vacuum pump, wherein the exhaust end of the exhaust pipe is hermetically connected to the first end of an exhaust cap, and the leakage detection vacuum pressure gauge, the vacuum breaking valve, the vacuum valve and the vacuum pump are sequentially arranged on the exhaust pipe from behind the exhaust cap.
8. A leak detection device for a single tube in a tube heat exchanger as claimed in claim 7 wherein: the vacuum pumping assembly further comprises an air filter screen, and the air filter screen is arranged between the vacuum valve and the vacuum pump on the exhaust pipe.
9. A leak detection device for a single tube in a tube heat exchanger as recited in claim 8 wherein: the vacuum pumping assembly further comprises a vacuum pump vacuum pressure gauge, and the vacuum pump vacuum pressure gauge is arranged between the air filter screen and the vacuum pump on the exhaust pipe.
10. The leakage detection method for the single-pipe leakage detection device in the tubular heat exchanger according to claim 7, which specifically comprises the following steps:
(1) preparing a tube plate: after the tubular heat exchanger is disassembled, cleaning tube plates at two ends of the tubular heat exchanger until the original metal surface is exposed or the coupled hard scale/corrosion surface is not influenced;
(2) preparation before air extraction: coating coupling agents on tube plates and tube openings at two ends of a single heat exchange tube to be detected in a tube heat exchanger, respectively fastening opening ends of an air extracting cap and a vacuum cap outside an air extracting end and a vacuum sealing end in the tube openings at the two ends, ensuring that the air extracting cap and the vacuum cap can completely and hermetically cover a welding or expansion opening part of the heat exchange tube to be detected on the tube plates, matching annular plane sealing gaskets at the opening ends of the air extracting cap and the vacuum cap with tube plate planes around the tube openings to be detected, pressing, and ensuring that a joint surface is tightly attached;
(3) air extraction: opening a vacuum valve, opening a vacuum pump, pumping air in a heat exchange tube to be detected to a vacuum pump through an exhaust tube, the vacuum valve and a filter screen connected to an exhaust cap, discharging the air, pumping the air until negative pressure is generated in the heat exchange tube, enabling the exhaust cap and the vacuum cap to be self-absorbed on a tube plate, closing the vacuum pump and the vacuum valve when the gauge pressure of a vacuum pressure gauge to be detected to leak is reduced to below-600 mmHg/-80kPa, continuously observing for about 10 seconds, judging that the heat exchange tube has no leak point if the vacuum is not obviously reduced, and otherwise, proving that the heat exchange tube has leakage if the vacuum cannot be maintained;
(4) tube replacement: and opening the vacuum breaking valve, recovering the normal pressure, and then removing the air exhaust cap and the vacuum cap to change to the next heat exchange tube to be detected.
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| CN114878107A (en) * | 2022-06-08 | 2022-08-09 | 华能国际电力股份有限公司德州电厂 | Automatic leakage detection device and method for air exhaust of heat exchange tube of condenser |
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| Publication number | Priority date | Publication date | Assignee | Title |
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