CN203744580U - Solar phase-change water heater with finned tube and reinforced twisted strip - Google Patents
Solar phase-change water heater with finned tube and reinforced twisted strip Download PDFInfo
- Publication number
- CN203744580U CN203744580U CN201420074784.8U CN201420074784U CN203744580U CN 203744580 U CN203744580 U CN 203744580U CN 201420074784 U CN201420074784 U CN 201420074784U CN 203744580 U CN203744580 U CN 203744580U
- Authority
- CN
- China
- Prior art keywords
- twisted strip
- heat
- water heater
- twisted
- change material
- 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.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S60/00—Arrangements for storing heat collected by solar heat collectors
- F24S60/10—Arrangements for storing heat collected by solar heat collectors using latent heat
-
- 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
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Building Environments (AREA)
Abstract
The utility model discloses a solar phase-change water heater with a finned tube and a reinforced twisted strip. The solar phase-change water heater with the finned tube and the reinforced twisted strip comprises a rectangular steel container. The rectangular steel container is filled with a composite phase-change material. A heat collecting tube is covered with the composite phase-change material. A heat-absorbing board core is installed on the upper surface of the composite phase-change material. Tempered glass is installed on the upper surface of the heat-absorbing board core. Thermal-insulation materials are installed on the periphery of the heat-absorbing board core and the periphery of the composite phase-change material. A bottom board is arranged on the lower surface of the composite phase-change material. A shared frame is arranged on the periphery of the tempered glass, the periphery of the heat-absorbing board core, the periphery of the thermal-insulation materials and the periphery of the bottom board. According to the solar phase-change water heater with the finned tube and the reinforced twisted strip, the purposes of large energy storage and discharge intensity, constant temperature, pressure-bearing type water outputting, and high heat-transmission efficiency are achieved and the solar phase-change water heater can be used in overcast and rainy weather and used for realizing load shifting of electricity.
Description
Technical field
The utility model belongs to solar energy phase transition technical field, relates to a kind of solar energy phase transition water heater with finned tube and twisted strip strengthening.
Background technology
Current, due to advantages such as security are higher, non-friable, bearing capacity is strong, the effective daylighting area of unit is large, flat plate solar water heater relative vacuum tube solar water heater is more suitable for the instructions for use of current people to water heater, and flat plate solar water heater is easy to install, completely become one with building, have a wide range of applications.
Existing flat water heater adopts sensible heat to hold exoergic mostly, and rate of heat transfer is too low, and energy storage density is little, even if adopt phase transformation also mostly to adopt heat pipe gas-liquid phase transition, because of difficult sealing, the shortcoming such as cost is high, heat waste is large, implements relatively difficulty.
Phase-change material is organic phase change material (as paraffin or polyglycerol) particularly, the latent heat of phase change of Yin Qigao, suitable phase transition temperature, without advantages such as surfusion, nontoxic low cost, stable, wide material sources, and be widely used in building in the fields such as accumulation of energy, solar energy thermal-power-generating, aviation, refrigeration.
At flat plate solar water heater, install organic phase change material additional, can greatly improve and hold exoergic capacity and density, improve rate of heat transfer, realize the stable and constant temperature supply of hot water.But employing organic phase change material, thermal conductivity is low, holds exergic efficiency low, has certain volume to change.
Utility model content
The utility model provides a kind of solar energy phase transition water heater with finned tube and twisted strip strengthening, solved that the solar thermal collector capacity usage ratio existing in prior art is low, the scope of application is little, weight is excessive, cannot effectively solve the problem at overcast and rainy use hot water.
The technical scheme that the utility model adopts is, a kind of solar energy phase transition water heater with finned tube and twisted strip strengthening, comprise a rectangle steel container made, in rectangle steel container made, be filled with composite phase-change material, in composite phase-change material, be enclosed with thermal-collecting tube, upper surface at composite phase-change material is provided with heat-absorbing plate core, heat-absorbing plate core upper surface is provided with safety glass, at heat-absorbing plate core and composite phase-change material surrounding, insulation material is installed, the lower surface of composite phase-change material is provided with base plate, safety glass, heat-absorbing plate core, the surrounding of insulation material and base plate is provided with common frame.
Feature of the present utility model also comprises:
The structure of thermal-collecting tube is, comprises snakelike flat segments and bend loss, at flat segments outer surface interval, a plurality of fins is installed, and in flat segments inner chamber, along axle center, is provided with twisted strip.
The shape of fin is selected rectangle, circle, zigzag, longitudinal fin or transverse fin, and between fin, has spacing.
Twisted strip is selected single twisted strip, two twisted strip, three twisted strips, four twisted strips, sawtooth twisted strip and various remodeling thereof; Perforate, fin, sawtooth, cylindric flow-disturbing thing or spherical shape flow-disturbing thing are set on twisted strip.
Twisted strip not only contains a twisted strip, different according to heat hot water time requirement, also comprises two twisted strips placed side by side, three twisted strips or four twisted strips that rotation direction is contrary.
Heat-absorbing plate core is fixed by pressing plate and frame, and safety glass is fixed by sealing joint strip and frame.
Safety glass is double-deck, and transparent, thickness in monolayer is greater than 3mm, leaves certain interval between bilayer, the composition module that is evacuated, and interior surfaces of glass scribbles antireflection coatings.
Rectangle steel container made is provided with expansion joint and relief valve.
Auxiliary electrical heater silk is installed in composite phase-change material.
Heat-absorbing plate core and composite phase-change material adopt heat-conducting silicone grease to carry out bonding.
The beneficial effects of the utility model are that concrete feature comprises:
1) pressure that composite phase-change material module causes by expansion joint and relief valve minimizing change in volume changes, and improves container bearing capacity;
2) be embedded with heater strip in the middle of composite phase-change material module, due to phase-change material hold exoergic characteristic, can carry out " peak load shifting " to electric power, for the hot water supply of rainy weather, save electric energy, greatly improve the utilization rate of the energy;
3) fin of thermal-collecting tube outer surface can increase the outer heat transfer area of thermal-collecting tube, and expanded graphite or nano material are doped in paraffin can improve paraffin thermal conductivity;
4) in thermal-collecting tube, adopt twisted strip augmentation of heat transfer, reduce pipe internal thermal resistance, can greatly improve convection heat transfer' heat-transfer by convection speed in pipe, during free convection, effect is better;
5) pressure-bearing type water outlet, hold that exoergic ability is large, collecting efficiency is high, temperature stabilization, energy storage density is large;
6) save traditional water tank, instant heating i.e. use, antifreeze and anti-overheated; Modular construction, ease of assembly, simple and reliable, easy to maintenance, bear pressure high.
Accompanying drawing explanation
Fig. 1 is the structural representation of the utility model solar energy phase transition water heater;
Fig. 2 is the thermal-collecting tube structural representation in the utility model solar energy phase transition water heater;
Fig. 3 is the fin structure schematic diagram of thermal-collecting tube outer surface in the utility model;
Fig. 4 is the schematic diagram of the single twisted strip in typical square-section in the utility model;
Fig. 5 is the two twisted strip side views in square-section in the utility model;
Fig. 6 is the two twisted strip top views in square-section in the utility model;
Fig. 7 is the two twisted strip side views of diamond-shaped cross-section in the utility model;
Fig. 8 is the two twisted strip side views of oval cross section in the utility model;
Fig. 9 is three twisted strip side views in the utility model;
Figure 10 is three twisted strip top views in the utility model;
Figure 11 is four twisted strip side views in the utility model;
Figure 12 is four twisted strip top views in the utility model;
Figure 13 is added with triangle fin list twisted strip side view in the utility model;
Figure 14 is the two twisted strip side views of added with triangle fin in the utility model;
Figure 15 adds rectangular tab list twisted strip side view in the utility model;
Figure 16 adds the two twisted strip side views of rectangular tab in the utility model;
Figure 17 is added with triangle fin list arranged side by side twisted strip side view in the utility model;
Figure 18 is the two twisted strip side views of added with triangle fin arranged side by side in the utility model;
Figure 19 adds the two twisted strip side views of sky rib in the utility model;
Figure 20 adds the two twisted strip side views one in hole in the utility model;
Figure 21 adds the two twisted strip side views two in hole in the utility model;
Figure 22 adds the two twisted strip side views three in hole in the utility model;
Figure 23 is zigzag twisted strip side view in the utility model;
Figure 24 is zigzag twisted strip top view in the utility model.
In figure, 1, safety glass, 2, sealing joint strip, 3, heat-absorbing plate core, 4, pressing plate, 5, frame, 6, composite phase-change material, 7, thermal-collecting tube, 8, insulation material, 9, base plate, 10, fin, 11, twisted strip.
The specific embodiment
With reference to Fig. 1, the structure of the utility model device is, comprise a rectangle steel container made, this rectangle steel container made is provided with expansion joint and relief valve, in rectangle steel container made, be filled with composite phase-change material 6, in composite phase-change material 6, be installed with thermal-collecting tube 7, at the upper surface of composite phase-change material 6, heat-absorbing plate core 3 is installed, at heat-absorbing plate core 3 upper surfaces, safety glass 1 is installed, at heat-absorbing plate core 3 and composite phase-change material 6 surroundings, insulation material 8 is installed; Lower surface at composite phase-change material 6 is provided with base plate 9, the surrounding of safety glass 1, heat-absorbing plate core 3, insulation material 8 and base plate 9 is provided with common frame 5, heat-absorbing plate core 3 is fixing with frame 5 by pressing plate 4, and safety glass 1 is fixing with frame 5 by sealing joint strip 2.
Safety glass 1 is for seeing through solar energy, play the effect of security protection, it below safety glass 1, is heat-absorbing plate core 3, heat-absorbing plate core 3 is composite phase-change material 6 below, thermal-collecting tube 7 with fin and twisted strip is placed in composite phase-change material 6, at heat-absorbing plate core 3 and composite phase-change material 6 outsides, insulation material 8 is installed, by pressing plate 4, seal 2 and base plate 9, heat-absorbing plate core 3 and composite phase-change material 6 is fixed in frame 5.
Composite phase-change material 6 is selected doping high thermal conductivity graphite (or nano material) in paraffin of the prior art (or polyglycerol) (or arbitrary ratio mixture of paraffin and polyglycerol adds graphite or nano material).Composite phase-change material 6 adopts rectangle steel container made splendid attire, and rectangle steel container made is provided with expansion joint and relief valve, the pressure variation bringing for alleviating phase-change material change in volume.Auxiliary electrical heater silk is also installed, for the heating of rainy weather and " peak load shifting " of electric power in composite phase-change material 6.
The matrix of composite phase-change material 6 is large single paraffin or polyglycerol or the two the arbitrary ratio mixture of latent heat of phase change that is suitable for low-temperature heat accumulating, and fusing point is 40 ℃～70 ℃.In phase-change material matrix, add expanded graphite or nano material cupric oxide, silica, alundum (Al2O3), CNT, Graphene, hold exoergic density large, temperature constant, thermal conductivity is high.
On heat-absorbing plate core 3, scribble coating for selective absorption.Heat absorbing coating is that the coating for selective absorption that absorptivity is high, reflectivity is low (adopts the standby Mo/Al of Vacuum Magnetic sputter coating legal system
2o
3, Ni/NiO, Co/Ag, Cr/Cr
2o
3, Ni/Cr, Ni/SiO
2).
It is bonding that heat-absorbing plate core 3 and composite phase-change material 6 adopt heat-conducting silicone greases to carry out, to reduce thermal contact resistance.Auxiliary electrical heater silk is wrapped in the elbow of thermal-collecting tube 7 or is directly placed in composite phase-change material 6.
Base plate is placed in insulation material bottom for stationary heat hydrophone.
The heat-exchange working medium of flowing through in thermal-collecting tube 7 is anti-icing fluid, conduction oil or water.
Insulation material 8 is polyurethane or asbestos or phenol formaldehyde foam or alumina silicate or porcelain tendre.
Safety glass 1 is double-deck, and transparent, thickness in monolayer is greater than 3mm, leaves certain interval between bilayer, the composition module that is evacuated, and interior surfaces of glass scribbles antireflection coatings.
As Fig. 2, the structure of thermal-collecting tube 7 is, comprises snakelike flat segments and bend loss, at flat segments outer surface interval, a plurality of fins 10 is installed, and the shape of fin 10 is selected rectangle, circle, zigzag, longitudinal fin or transverse fin, and between fin, has spacing, as Fig. 3; In flat segments inner chamber, along axial line, be provided with twisted strip 11.
Single twisted strip, two twisted strip, three twisted strips, four twisted strips, sawtooth twisted strip and various remodeling thereof are selected in the setting of twisted strip 11 as required, the twisted strip that twisted strip is selected traditional long twisted strip, short twisted strip and equidistantly split; Perforate, fin, sawtooth, cylindric flow-disturbing thing or spherical shape flow-disturbing thing are set on twisted strip; Twisted strip not only contains a twisted strip, different according to heat hot water time requirement, also comprises two twisted strips placed side by side, three twisted strips or four twisted strips that rotation direction is contrary.
Embodiment enumerates following several, and each figure has all provided the structural representation of a pitch:
As Fig. 4, it is typical single twisted strip shape;
As Fig. 5, Fig. 6, be the two twisted strip shapes in square-section;
As Fig. 7, be the two twisted strip shapes of diamond-shaped cross-section;
As Fig. 8, be the two twisted strip shapes of oval cross section;
As Fig. 9, Figure 10, be three twisted strip shapes;
As Figure 11, Figure 12, be four twisted strip shapes;
As Figure 13, it is added with triangle fin list twisted strip shape;
As Figure 14, be the two twisted strip shapes of added with triangle fin;
As Figure 15, for adding rectangular tab list twisted strip shape;
As Figure 16, for adding the two twisted strip shapes of rectangular tab;
As Figure 17, for adding delta wing sheet list twisted strip shape arranged side by side;
As Figure 18, for adding the two twisted strip shapes of delta wing sheet arranged side by side;
As Figure 19, for adding the two twisted strip shapes of sky rib;
As Figure 20, Figure 21, Figure 22, for adding the two twisted strip shapes in hole;
As Figure 23, Figure 24, it is zigzag twisted strip shape.
The operation principle of the utility model device is, at the outer fin 10 of metal material that utilizes of thermal-collecting tube 7, increase heat transfer area, and by the expanded graphite that adulterates (or nano material), improve the thermal conductivity formation high efficiency composition phase-change material of paraffin (or polyglycerol) in paraffin.Outside thermal-collecting tube 7, by composite phase-change material accumulation of energy, while needing, exoergic, to tube wall, then is passed to the working medium in pipe by tube wall.In thermal-collecting tube 7, pass through twisted strip 11, improved the displacement intensity of the interior center of pipe and main flow area fluid, attenuate thermal boundary layer, reduce dirt deposition, temperature is more uniformly distributed, increase flow path and effective heat transfer temperature difference, improve the turbulivity of working media, thereby greatly improve the convection heat transfer' heat-transfer by convection speed in pipe.In free convection situation, can also increase the circulation rate of working media.The utility model, in order to solve the volumetric expansion problem of paraffin phase change material, is provided with expansion joint and relief valve in addition, and the bearing capacity of rectangle steel container made is further strengthened.The discontinuity and the instability problem that efficiently solve that solar energy is subject to round the clock, the impact of the factor such as season and sleety weather etc. show.Can during obtaining solar energy, carry out heat accumulation, can institute's quantity of heat storage be discharged to supply in the rest periods again and use.Can also at night, carry out by composite phase-change material the accumulation of energy of low-price electricity in addition, daytime, exoergic was used or domestic hot-water with provider, reached the effect of electric power being carried out to peak load shifting, carried out the cascade utilization of electric power, reached energy-conservation effect.
Claims (10)
1. the solar energy phase transition water heater with the strengthening of finned tube and twisted strip, be characterized in: comprise a rectangle steel container made, in rectangle steel container made, be filled with composite phase-change material (6), in composite phase-change material (6), be enclosed with thermal-collecting tube (7), upper surface at composite phase-change material (6) is provided with heat-absorbing plate core (3), heat-absorbing plate core (3) upper surface is provided with safety glass (1), at heat-absorbing plate core (3) and composite phase-change material (6) surrounding, insulation material (8) is installed, the lower surface of composite phase-change material (6) is provided with base plate (9), safety glass (1), heat-absorbing plate core (3), the surrounding of insulation material (8) and base plate (9) is provided with common frame (5).
2. the solar energy phase transition water heater with the strengthening of finned tube and twisted strip according to claim 1, be characterized in: the structure of described thermal-collecting tube (7) is, comprise snakelike flat segments and bend loss, at flat segments outer surface interval, a plurality of fins (10) are installed, in flat segments inner chamber, along axle center, are provided with twisted strip (11).
3. the solar energy phase transition water heater with finned tube and twisted strip strengthening according to claim 2, is characterized in: the shape of described fin (10) is selected rectangle, circle, zigzag, longitudinal fin or transverse fin, and between fin, has spacing.
4. the solar energy phase transition water heater with finned tube and twisted strip strengthening according to claim 2, is characterized in: described twisted strip (11) is selected single twisted strip, two twisted strip, three twisted strips, four twisted strips, sawtooth twisted strip and various remodeling thereof; Perforate, fin, sawtooth, cylindric flow-disturbing thing or spherical shape flow-disturbing thing are set on twisted strip (11).
5. the solar energy phase transition water heater with the strengthening of finned tube and twisted strip according to claim 4, be characterized in: described twisted strip (11) not only contains a twisted strip, different according to heat hot water time requirement, also comprise two twisted strips placed side by side, three twisted strips or four twisted strips that rotation direction is contrary.
6. the solar energy phase transition water heater with finned tube and twisted strip strengthening according to claim 1, is characterized in: described safety glass (1) is for double-deck, transparent, thickness in monolayer is greater than 3mm, between bilayer, leave certain interval, the composition module that is evacuated, interior surfaces of glass scribbles antireflection coatings.
7. the solar energy phase transition water heater with finned tube and twisted strip strengthening according to claim 1, is characterized in: described rectangle steel container made is provided with expansion joint and relief valve.
8. the solar energy phase transition water heater with finned tube and twisted strip strengthening according to claim 1, is characterized in: described composite phase-change material is provided with auxiliary electrical heater silk in (6).
9. the solar energy phase transition water heater with finned tube and twisted strip strengthening according to claim 1, is characterized in: described heat-absorbing plate core (3) adopts heat-conducting silicone grease to carry out bonding with composite phase-change material (6).
10. the solar energy phase transition water heater with the strengthening of finned tube and twisted strip according to claim 1, be characterized in: described heat-absorbing plate core (3) is fixing by pressing plate (4) and frame (5), safety glass (1) is fixing by sealing joint strip (2) and frame (5).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420074784.8U CN203744580U (en) | 2014-02-20 | 2014-02-20 | Solar phase-change water heater with finned tube and reinforced twisted strip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420074784.8U CN203744580U (en) | 2014-02-20 | 2014-02-20 | Solar phase-change water heater with finned tube and reinforced twisted strip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203744580U true CN203744580U (en) | 2014-07-30 |
Family
ID=51344370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420074784.8U Expired - Fee Related CN203744580U (en) | 2014-02-20 | 2014-02-20 | Solar phase-change water heater with finned tube and reinforced twisted strip |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203744580U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112984052A (en) * | 2015-09-18 | 2021-06-18 | 萧爱工业有限公司 | Advanced component based conveyor belt splicer |
| CN114362393A (en) * | 2021-12-03 | 2022-04-15 | 中车永济电机有限公司 | Stator core with axial ventilation holes provided with spacing torsion bands |
-
2014
- 2014-02-20 CN CN201420074784.8U patent/CN203744580U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112984052A (en) * | 2015-09-18 | 2021-06-18 | 萧爱工业有限公司 | Advanced component based conveyor belt splicer |
| CN114362393A (en) * | 2021-12-03 | 2022-04-15 | 中车永济电机有限公司 | Stator core with axial ventilation holes provided with spacing torsion bands |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Jamar et al. | A review of water heating system for solar energy applications | |
| Chow et al. | Potential use of photovoltaic-integrated solar heat pump system in Hong Kong | |
| CN102607200B (en) | Inorganic high-efficiency flat superconducting flat-plate solar collector | |
| CN101285622A (en) | Energy storage -type solar flat-board heat collector for increasing metal fin | |
| CN103531652A (en) | Cooling device for dish-type solar concentrating photovoltaic cell panel | |
| CN204830575U (en) | Solar energy phase transition wall source heat pump system | |
| CN203744580U (en) | Solar phase-change water heater with finned tube and reinforced twisted strip | |
| CN102607099A (en) | Passive type solar heat collecting box | |
| CN101846404A (en) | Porous material solar energy air heat-collecting device | |
| CN201858919U (en) | Heat storage device | |
| CN204145410U (en) | Photovoltaic and photothermal building integration system | |
| CN202613802U (en) | High temperature heat accumulation and heat exchange device for solar thermal power generation | |
| CN202254393U (en) | Heat-pipe-type solar vacuum heat collector with heat accumulation function | |
| CN202126000U (en) | Water heating-electric heating dual-purpose phase change copper-aluminum combined wing type radiator | |
| CN204128219U (en) | A kind of solar energy phase transition heat accumulation heating plant | |
| CN103868137A (en) | Novel solar heat pipe heat collecting and storing floor radiation heating system | |
| CN115013853B (en) | Solar phase-change heat-storage heating system containing phase-change materials with different melting points | |
| CN111350292A (en) | Multi-energy complementary composite phase-change energy-storage wall system | |
| CN202581864U (en) | Inorganic high-efficiency flat superconducting flat-plate solar energy heat collector | |
| CN202709828U (en) | Horizontal fall heat pipe for solar water heater | |
| CN204757416U (en) | Warm for air piping system phase transition heat accumulation body in solar energy | |
| CN101003988A (en) | Construction system of heat collection and heat storage from solar energy | |
| CN107218734A (en) | A kind of solar powered heating cooling combined supply system | |
| CN203704386U (en) | Heat storage type solar low-temperature heat supply system | |
| CN203719155U (en) | Phase-change energy-saving solar vacuum heat collection tube |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140730 Termination date: 20160220 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |