CN204202456U - Asymmetric phase-change heat-exchanger - Google Patents
Asymmetric phase-change heat-exchanger Download PDFInfo
- Publication number
- CN204202456U CN204202456U CN201420660425.0U CN201420660425U CN204202456U CN 204202456 U CN204202456 U CN 204202456U CN 201420660425 U CN201420660425 U CN 201420660425U CN 204202456 U CN204202456 U CN 204202456U
- Authority
- CN
- China
- Prior art keywords
- plate
- heat exchange
- cell
- header board
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn - After Issue
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/30—Technologies for a more efficient combustion or heat usage
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/14—Thermal energy storage
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The utility model discloses a kind of asymmetric phase-change heat-exchanger, the heat exchange element mainly comprising heat exchanger shell and be located in heat exchange housing, described heat exchange element is at least one, its heat exchange element is made up of header board, rear plate and the multiple honeycomb fin plates be located between header board and rear plate, described honeycomb fin plate is made up of left finned plate and right finned plate, and described left finned plate and right finned plate are respectively equipped with guiding region, cell and seal area.Asymmetric phase-change heat-exchanger described in the utility model has that energy-conserving and environment-protective, corrosion resistance are high, long service life, the feature that floor space is little, easy for installation.
Description
Technical field
The utility model relates to a kind of heat-exchanger rig, particularly a kind of asymmetric phase-change heat-exchanger that can produce turbulent gas.
Background technology
Tradition flue gas waste heat recovery (solution-air) heat exchanger is generally pipe type heat transfer: roughly include heat pipe, copper thorn pipe, steel pipe, finned tube are several, pipe heat exchanger is widely used in super-pressure production process, can be used for flow little, the occasion that required heat transfer area is few.The advantage of pipe type heat transfer is: structure is simple, easy to process, high pressure resistant, and complete adverse current can be kept to make mean logarithmic temperature difference large.Its shortcoming is: structure is not compact, and metal wastage is large, and the many and leakiness of joint, takes up an area larger.Also some factory have employed plate type heat exchanger and carries out heat exchange, plate type heat exchanger is in the market primarily of many ripple heat transfer plates, interval as requested, compressed by rubber gasket and make, when assembling, corrugated plating becomes to be alternately arranged, with binding agent, rubber seal lath is fixed between plate and plate, thus prevent fluid leakage, and form independently flow channel for liquids, its shortcoming is: every block corrugated plating adopts independent heat exchange, independent water outlet, therefore cause the fluid temperature (F.T.) in every block corrugated plating inconsistent, the a part of temperature of fluid possibility that it exchanges away is very high, the problem that part temperature is very low, again owing between corrugated plating being all the Seal Design adopting made of one piece, make flue gas can produce Efficient Cycle at heat exchanger, heat exchange efficiency is caused not to be very high, be exactly present plate type heat exchanger many employings rubber sealing and common welding in addition, result in its compressive property also poor.As can be seen here, at present no matter that pipe heat exchanger or plate type heat exchanger are in application process, all there is many problems needing to solve, as: the cold end corrosion problem of heat exchange material, due to the reduction of flue-gas temperature, water vapor condensation is separated out, and be all dissolved in condensed water by the sour gas that complete for the unburned in flue gas material and burning produce, result in condensed water has certain corrosive power.If use common finned carbon steel tubes, then need not 3 years time whole condensation energy-saving device fin around will be corroded totally, efficiency can decline gradually, and the leakage flue gas until last condensation energy-saving device leaks, service life is lower.The too low meeting of boiler tail outlet exhaust gas temperature makes the wall temperature of heat exchanger lower than the set point (being called acid dew point) of sulfuric acid vapor, causes the heavy corrosion of metal heat-exchange heating surface of tubes.The minimum wall temperature of the low-level (stack-gas) economizer selected by common engineering application should exceed flue gas dew point temperature about 10 DEG C, thus reach and prevent low temperature dewing corrosion, thus cause the heat exchanger of metal material can only reclaim the boiler smoke of more than about 120 DEG C exhaust gas temperatures, can not smoke discharging residual heat be made full use of, limit the range of application of low-level (stack-gas) economizer; Heat exchange element compressive property is poor, moreover present heat exchanger is due to metallic heat exchanging tube, and volume is large, causes heat exchanger itself relatively heavy, several tons at least, the even weight of tens tons, and boiler back segment requires larger space mounting.
Utility model content
The utility model provides that a kind of energy-conserving and environment-protective, corrosion resistance are high, long service life, the asymmetric phase-change heat-exchanger that floor space is little.
In order to reach above-mentioned purpose of design, the technical solution adopted in the utility model is as follows:
A kind of asymmetric phase-change heat-exchanger, the heat exchange element mainly comprising heat exchanger shell and be located in heat exchange housing, described heat exchange element is at least one, its heat exchange element is by header board, rear plate and the multiple honeycomb fin plates be located between header board and rear plate form, its header board is provided with water inlet pipe road junction and outlet pipe road junction, described honeycomb fin plate is made up of left finned plate and right finned plate, described left finned plate and right finned plate are respectively equipped with guiding region, cell and seal area, described guiding region comprises and header board water inlet pipe road junction, the water inlet that outlet pipe road junction is corresponding and delivery port, the surrounding of water inlet is provided with many guiding gutters, guiding gutter is connected with the water inlet end of cell, the rear end of cell is connected with delivery port, described cell is made up of the evagination cell body of multiple even arrangement, the inner face of cell is made to form one " waveform " runner, the crest of each evagination cell body also has water hole, described seal area is arranged along the outer peripheral edge of cell and guiding region, and the horizontal plane of seal area is higher than evagination cell body trough level face, left finned plate forms a hollow cavity with the seal area of right finned plate after welding, formed fixing by welding and header board and rear plate after polylith honeycomb fin plate ordered stacks, the water hole being disposed adjacent honeycomb fin plate is connected, its periphery passes through spot welding seal, the inner chamber of the polylith honeycomb fin plate after combination forms water stream channel, its waveform outer wall forms flue gas flow channel.
Further, the evagination cell body of described cell is a kind of octagonal structure, the straight line of its adjacent evagination cell body overlaps, after the combination of many groups evagination cell body, the space on its oblique line limit forms flue gas flow channel, and its evagination cell body waveform outer wall and hypotenuse space form a kind of flue gas flow channel of cruciform shape.
Further, described left finned plate and right finned plate under vacuum high-temperature by copper or nickel successively with header board and rear plate welded seal.
The beneficial effect of asymmetric phase-change heat-exchanger described in the utility model is: have employed polylith octagonal cellular modularization asymmetric drift template as main heat exchange element, thus make heat exchange element form gas flow and the flow channel for liquids of right-angled intersection, the runner of right-angled intersection can make fluid turbulization under less flow velocity, form higher heat transfer coefficient, the sealing of heat exchange element and splicing are by copper or nickel welded seal under vacuum high-temperature, not only ensure the anti-leakage of heat exchange element, also ensure that the crushing resistance of heat exchange element simultaneously.Heat exchange element can adopt modular form to combine according to the actual requirements, effectively can save and take up an area space, and adapts to the heat-removal equipment of different size, also facilitates user and carries out dismantling and keeping in repair.
Accompanying drawing explanation
Fig. 1 is overall structure schematic diagram of the present utility model;
Fig. 2 is the structural representation of left finned plate or right finned plate in the utility model;
Fig. 3 is the structural representation of cell in the utility model.
Detailed description of the invention
Below in conjunction with Figure of description, detailed description of the invention of the present utility model is described in detail.Obviously, described embodiment is only a part of embodiment of the present utility model, and other embodiment that those skilled in the art obtains under the prerequisite not paying creative work all belongs to protection domain of the present utility model.
The asymmetric phase-change heat-exchanger of one that theres is provided of the utility model as shown in Figure 1, form primarily of heat exchanger shell and the heat exchange element be located in heat exchange housing, the specification size of asymmetric covert heat exchanger is made according to the large I of the exhaust smoke level of heat dissipation equipment, in heat exchanger shell, multiple heat exchange element can be set, each heat exchange element has included header board 1, rear plate 2 and multiple honeycomb fin plate 3(header board and the rear plate in the utility model be located between header board 1 and rear plate 2 are a kind of 304 corrosion resistant plates, honeycomb fin plate is made up of 316L stainless steel), its header board 1 is provided with water inlet pipe road junction 11 and outlet pipe road junction 12, described honeycomb fin plate 3 is made up of left finned plate 4 and right finned plate 5, as Fig. 2, described left finned plate 4 and right finned plate 5 shown in 3 are respectively equipped with corresponding guiding region 41, cell 42 and seal area 43, described guiding region 41 comprises and header board water inlet pipe road junction 11, the water inlet 411 of outlet pipe road junction 12 correspondence and delivery port 412, the surrounding of water inlet 411 is provided with many guiding gutters 413, guiding gutter 413 is connected with the water inlet end of cell 42, the rear end of cell 42 is connected with delivery port 412, described cell 42 is made up of the evagination cell body 421 of multiple even arrangement, the inner face of cell is made to form one " waveform " runner, the crest of each evagination cell body 421 also has water hole 422, evagination cell body 421 is a kind of octagonal structure, the straight line of its adjacent evagination cell body 421 overlaps, after many groups evagination cell body 421 combines, the space on its oblique line limit forms flue gas flow channel 423, the waveform outer wall of its evagination cell body 421 and hypotenuse space form a kind of flue gas flow channel of cruciform shape, described seal area 43 is arranged along the outer peripheral edge of cell 42 and guiding region 41, and the horizontal plane of seal area is higher than evagination cell body 421 trough level face, left finned plate 4 forms a hollow cavity with the seal area of right finned plate 5 after welding, formed fixing by welding and header board and rear plate after polylith honeycomb fin 3 plate ordered stacks, the water hole 422 being disposed adjacent honeycomb fin plate 3 is connected, its periphery passes through spot welding seal, the inner chamber of the polylith honeycomb fin plate 3 after combination forms water stream channel, its waveform outer wall forms flue gas flow channel.
The processing technology of the utility model heat exchange element, comprises the following steps:
S1. selection, chooses the processing base material of 304 stainless steels as header board and rear plate, chooses the processing base material of 316L stainless steel as left finned plate, right finned plate;
S2. punch forming, first strikes out planar structure by header board and rear plate, and left finned plate, right finned plate are struck out octagonal honeycomb wave-shape board;
S3. two times punch and welding, under vacuum high-temperature environment, overlapping with right finned plate for the left finned plate of correspondence punching press being formed one group of honeycomb wing plate is fixed on header board, its side seam copper or nickel welded seal, so repeatedly carry out lamination punching press to left finned plate and right finned plate to fix, plate after its rear end is fixing, in lamination process, the periphery of the water hole on adjacent cell wing plate carries out welded seal by copper or nickel.
Concrete installation and use:
The size of heat exchange housing is set according to the maximum exhaust smoke level of fume extractor, and in heat exchange heat exchange housing, N number of heat exchange element is installed, its adjacent heat exchange element keeps being communicated with by water inlet and delivery port, the flue gas flow channel import of the corresponding fume extractor in B face of heat exchange element as shown in Figure 1, the A face of heat exchange element is the outlet/inlet of flow channel for liquids, when needing heat exchange, water inlet to heat exchange element A face injects cryogen, the inner chamber runner of honeycomb fin plate is entered by the water inlet of honeycomb fin plate, because honeycomb fin plate have employed the wave-shape board line of " concavo-convex " structure, thus increase the heat exchange area of fluid in honeycomb fin plate, again because honeycomb fin plate is provided with the water hole being formed and be communicated with, honeycomb fin plate is made to be clustered into connection, thus fluid forms turbulent flow in the inner chamber of honeycomb fin plate cluster, ensure that the mean temperature of fluid, the fluid temperature (F.T.) that heat exchange is gone out is homogeneous, flue gas enters heat exchange element by the B face of heat exchange element, and because honeycomb fin plate adopts the design of octagonal plate, its oblique line gap-forming gap flue gas flow channel, flue gas forms the turbulent flow of cruciform shape at honeycomb wing plate outer wall, play more comprehensively heat transfer effect.
What adopt due to heat exchange element is that 304 stainless steels and 316L stainless steel are as assembling base material, and have employed vacuum high-temperature punching press and vacuum high-temperature copper or nickel and carry out welded seal, ensure that the crushing resistance of heat exchange element, according to pressure test and performance constraint, the test pressure of heat exchange element runner under 225 degrees Celsius: 24 bar, vacuum test: 0.00005 bar, also can bear higher temperature when pressure is lower.
There is not bypass in the design, and the ripple of plate can make fluid turbulization under less flow velocity.So there is higher heat transfer coefficient, 3 ~ 5 times that are commonly considered as shell-and-tube heat exchanger.Complete same heat exchange task, adopt the comparison of shell-and-tube heat exchanger and employing the design; The heat exchange area of the design is only 1/3 ~ 1/4 of pipe shell type heat exchange area.
1) logarithmic mean temperature difference (LMTD) is large
The flowing of fluid in this brazing plate type heat exchanger is turbulent flow pattern, and its temperature difference correction factor is generally greater than 0.8, is generally 0.95.
2) floor space is little easy for installation
3) brazing plate type heat exchanger compact conformation, compares with conventional tubular heat exchanger:
Lower of same flow needs the heat exchange area of 1/10,
Same heat exchange area only has 1/10 size,
Same flow pressure drop only has the PHE of 5-10%,
4) lightweight
Brazing plate type heat exchanger is the gas-liquids heat exchanger of compact efficient.When completing same heat exchange task, the heat exchange area needed for plate type heat exchanger is less than shell-and-tube heat exchanger, lightweight, is only 1/8 ~ 1/10 of shell-and-tube heat exchanger weight, 1/15 ~ 1/20 of pipe heat exchanger.
5) terminal temperature difference is little
The fluid that shell-and-tube heat exchanger flows in shell side and heat-transfer surface interlock and stream, and also there is by-pass flow.And the flowing right-angled intersection of the cold and hot fluid of brazing plate type heat exchanger in plate type heat exchanger is in heat-transfer surface, and without by-pass flow; Make the terminal temperature difference of plate type heat exchanger very little like this, this heat exchanger terminal temperature difference is 5 DEG C. this heat energy for recovery low-temperature level is very favourable.
6) sealing factor is low
The sealing factor of plate type heat exchanger is much less than the sealing factor of shell-and-tube heat exchanger, and its reason is the high turbulences of fluid, and impurity not easily deposits; Between plate, the circulation dead band of passage is little; Stainless steel manufacture heat-transfer surface smooth and corrosion hardly staining metal; And cleaning easily.
7) medium heat exchange
8) be easy to change heat exchange area or path combination
With field working conditions parameter and requirement, suitably increase (or minimizing) module or path combination, the heat exchange area needing to increase (or minimizing) heat exchanger can be reached.
Last it is noted that above embodiment is only for illustration of the technical solution of the utility model, be not intended to limit; Although be described in detail the utility model with reference to previous embodiment, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of each embodiment technical scheme of the utility model.
Claims (3)
1. an asymmetric phase-change heat-exchanger, the heat exchange element mainly comprising heat exchanger shell and be located in heat exchange housing, it is characterized in that: described heat exchange element is at least one, its heat exchange element is by header board, rear plate and the multiple honeycomb fin plates be located between header board and rear plate form, its header board is provided with water inlet pipe road junction and outlet pipe road junction, described honeycomb fin plate is made up of left finned plate and right finned plate, described left finned plate and right finned plate are respectively equipped with guiding region, cell and seal area, described guiding region comprises and header board water inlet pipe road junction, the water inlet that outlet pipe road junction is corresponding and delivery port, the surrounding of water inlet is provided with many guiding gutters, guiding gutter is connected with the water inlet end of cell, the rear end of cell is connected with delivery port, described cell is made up of the evagination cell body of multiple even arrangement, the inner face of cell is made to form one " waveform " runner, the crest of each evagination cell body also has water hole, described seal area is arranged along the outer peripheral edge of cell and guiding region, and the horizontal plane of seal area is higher than evagination cell body trough level face, left finned plate forms a hollow cavity with the seal area of right finned plate after welding, formed fixing by welding and header board and rear plate after polylith honeycomb fin plate ordered stacks, the water hole being disposed adjacent honeycomb fin plate is connected, its periphery passes through spot welding seal, the inner chamber of the polylith honeycomb fin plate after combination forms water stream channel, its waveform outer wall forms flue gas flow channel.
2. asymmetric phase-change heat-exchanger according to claim 1, it is characterized in that: the evagination cell body of described cell is a kind of octagonal structure, the straight line of its adjacent evagination cell body overlaps, after the combination of many groups evagination cell body, the space on its oblique line limit forms flue gas flow channel, and its evagination cell body waveform outer wall and hypotenuse space form a kind of flue gas flow channel of cruciform shape.
3. asymmetric phase-change heat-exchanger according to claim 1, is characterized in that: described left finned plate and right finned plate under vacuum high-temperature by copper or nickel successively with header board and rear plate welded seal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420660425.0U CN204202456U (en) | 2014-11-06 | 2014-11-06 | Asymmetric phase-change heat-exchanger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420660425.0U CN204202456U (en) | 2014-11-06 | 2014-11-06 | Asymmetric phase-change heat-exchanger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204202456U true CN204202456U (en) | 2015-03-11 |
Family
ID=52660403
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420660425.0U Withdrawn - After Issue CN204202456U (en) | 2014-11-06 | 2014-11-06 | Asymmetric phase-change heat-exchanger |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204202456U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104315909A (en) * | 2014-11-06 | 2015-01-28 | 广州联聚节能技术有限公司 | Asymmetric phase change heat exchanger |
| CN107228589A (en) * | 2017-06-22 | 2017-10-03 | 中车青岛四方机车车辆股份有限公司 | A kind of vehicle-mounted liquid-solid-phase changeable energy storage heat-exchanger rig |
| CN109185907A (en) * | 2018-08-15 | 2019-01-11 | 华电电力科学研究院有限公司 | A kind of power station with smoke aerosol plume cancellation element and system and working method |
| CN110207516A (en) * | 2019-05-28 | 2019-09-06 | 西安热工研究院有限公司 | A kind of heat accumulating type heat storage exchanger core |
| CN112797452A (en) * | 2020-12-30 | 2021-05-14 | 嵊州市卡梦帝电器有限公司 | Oil fume suction device for split integrated stove and processing method thereof |
-
2014
- 2014-11-06 CN CN201420660425.0U patent/CN204202456U/en not_active Withdrawn - After Issue
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104315909A (en) * | 2014-11-06 | 2015-01-28 | 广州联聚节能技术有限公司 | Asymmetric phase change heat exchanger |
| CN104315909B (en) * | 2014-11-06 | 2016-03-23 | 广州联聚节能技术有限公司 | Asymmetric phase-change heat-exchanger |
| CN107228589A (en) * | 2017-06-22 | 2017-10-03 | 中车青岛四方机车车辆股份有限公司 | A kind of vehicle-mounted liquid-solid-phase changeable energy storage heat-exchanger rig |
| CN109185907A (en) * | 2018-08-15 | 2019-01-11 | 华电电力科学研究院有限公司 | A kind of power station with smoke aerosol plume cancellation element and system and working method |
| CN109185907B (en) * | 2018-08-15 | 2023-10-20 | 华电电力科学研究院有限公司 | Device and system for eliminating smoke plume of power station and working method |
| CN110207516A (en) * | 2019-05-28 | 2019-09-06 | 西安热工研究院有限公司 | A kind of heat accumulating type heat storage exchanger core |
| CN112797452A (en) * | 2020-12-30 | 2021-05-14 | 嵊州市卡梦帝电器有限公司 | Oil fume suction device for split integrated stove and processing method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN204202456U (en) | Asymmetric phase-change heat-exchanger | |
| WO2017162018A1 (en) | Counter-flow fin plate heat exchanger for gas-gas heat exchange | |
| CN108917174B (en) | Gas-electricity coupling limit condensation cast aluminum silicon magnesium gas water heater | |
| CN106705716A (en) | Plate-type gas gas-heat exchanger | |
| CN202303895U (en) | Finned-pipe type condensation heat exchanger for condensing-type gas water heater | |
| CN104315909B (en) | Asymmetric phase-change heat-exchanger | |
| CN201600062U (en) | Demountable complete contra-flow cooling medium to water heat exchanger for air source heat pump | |
| CN201081587Y (en) | Composite heat pipe heat exchanger | |
| CN203928789U (en) | A kind of boiler combined condenser | |
| CN101126565A (en) | Condensed type combustion gas water heater condensator | |
| CN208983628U (en) | A kind of fin-tube heat exchanger | |
| CN203719469U (en) | Pressure-bearing smoke waste heat exchanger | |
| CN217519888U (en) | Flue gas waste heat recovery gas heat exchange device based on heat medium is water | |
| CN202613757U (en) | Heat pump water heater | |
| CN202304502U (en) | Cylindrical heat exchanger | |
| CN104864600A (en) | Heat exchanger made by full stainless steel | |
| CN206656631U (en) | A kind of board-like gas gas-heat exchanger | |
| CN214198752U (en) | Air heater with anti-freezing function | |
| CN204227701U (en) | A kind of high-efficiency condensation heat exchanger | |
| CN109506498B (en) | Tubular ultra-high temperature gas cooler | |
| CN208382962U (en) | A kind of Demountable combined-type heat exchanger for high-temperature flue | |
| CN207635915U (en) | A kind of multitube distance tubular heat exchange device | |
| CN207043587U (en) | A kind of heat exchanger plates laser welding cooling device | |
| CN101666585B (en) | Flue gas waste heat recovery device | |
| CN204372899U (en) | A kind of station boiler shell-and-plate economizer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20150311 Effective date of abandoning: 20160323 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |