[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

CN205102403U - Three -return -stroke powder heat conduction oil boiler - Google Patents

Three -return -stroke powder heat conduction oil boiler Download PDF

Info

Publication number
CN205102403U
CN205102403U CN201520632604.8U CN201520632604U CN205102403U CN 205102403 U CN205102403 U CN 205102403U CN 201520632604 U CN201520632604 U CN 201520632604U CN 205102403 U CN205102403 U CN 205102403U
Authority
CN
China
Prior art keywords
convection bank
boiler
furnace
burner hearth
flue
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
Application number
CN201520632604.8U
Other languages
Chinese (zh)
Inventor
唐海清
周海能
王改
龚子林
沈玉华
柯志强
刘东平
席向东
张又红
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hangzhou Juneng Environmental Protection Technology Co ltd
Original Assignee
HANGZHOU JUNENG BOILER CO Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=55518182&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=CN205102403(U) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by HANGZHOU JUNENG BOILER CO Ltd filed Critical HANGZHOU JUNENG BOILER CO Ltd
Priority to CN201520632604.8U priority Critical patent/CN205102403U/en
Application granted granted Critical
Publication of CN205102403U publication Critical patent/CN205102403U/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Landscapes

  • Combustion Of Fluid Fuel (AREA)

Abstract

The utility model discloses a three -return -stroke powder heat conduction oil boiler, including circulating oil pump, furnace, complete combustion chamber, convection bank, afterbody indirect heating equipment, combustor, the sediment device that falls, next part case and first part case, the next part case sets up in boiler body's bottom, and first part case sets up the top at boiler body, the combustor is arranged at boiler furnace's front portion, top, bottom or lateral part, boiler body adopts full membrane wall structure, and 4 main downtakes are arranged in the four corners, the convection bank sets up in the convection bank flue, and the convection bank flue vertically sets up, and with furnace equal height, convection bank, main downtake and membrane wall's upper and lower both ends respectively with first part case and next part case UNICOM, complete combustion chamber and furnace vertically just equal height setting side by side back -to -back, furnace, complete combustion chamber, convection bank flue and afterbody indirect heating equipment establish ties in proper order and switch on, cloth has the combustion -supporting and denitration overgrate air of second grade in the furnace. The utility model has the characteristics of the flue gas flow is long, and the fuel burning is abundant, and heat exchange efficiency is high.

Description

A kind of three backhaul powder heat conducting oil boilers
Technical field
The utility model belongs to coal-burned industrial boiler field, is specifically related to one with coal dust, oil, gas, biomass powder, other flammable solid powder for fuel, for generation of three backhaul powder boilers of heating conduction oil.
Background technology
The energy resource structure of China is based on coal, and within the following long duration, based on fire coal, oil, gas, living beings, other solid fuels Industrial Boiler as a supplement will be the leading products of Industrial Boiler.
Traditional industry coal-boiler is based on grate firing boiler, and shortcoming is that efficiency of combustion is low, seriously polluted, is difficult to meet energy-saving and emission-reduction and pollutant emission requirement.
The powdery burning of coal, oil gas burning, powdery biomass combustion, other solid-fuelled powder state burnings are one of high performance clean burning modes of fuel, its efficiency of combustion can reach more than 98%, be a ripe combustion technology, be widely used at large-sized station boiler.In recent years, powder burning is also applied on Industrial Boiler, mostly adopts the horizontal two coil arrangement of YJW type or YJL type power formula two coil arrangement type water pipe structure, but there is certain deficiency:
1) YJL type vertical double-coil tubular construction boiler height is too high, and making and installation is inconvenient, maintenance difficulty.
2) YJW type horizontal dual coil pipes freezing of a furnace thorax is too low, and the too low fuel combustion of burner hearth is abundant not.
3) burning is even not, and front and back Temperature Difference Ratio is comparatively large, is unfavorable for reducing NO xcontent.
4) load regulation range is little, can only use single-fuel.
5) Boiler Ash, slag cleaning inconvenience.
6) boiler steel, furnace wall material consumption are large.
7) boiler room floor space is large, civil engineering cost is high.
8) boiler seal performance is not good, brick wall inleakage is large, boiler heat loss large, air-introduced machine power consumption is large.
Also has a kind of vertical type coal dust corner tube boiler, as shown in Figure 1.Adopt brick wall structure between its burner hearth 2 ' and secondary furnace, and the height of secondary furnace only has 1/2 to 1/3 of burner hearth.The boiler of this structure, the sidewall heat of burner hearth 2 ' can not effectively utilize on the one hand, and secondary furnace is height-limited on the other hand, and the flow process of high-temperature flue gas is shorter, and therefore the thermal efficiency of boiler is lower.In addition, owing to not reserving space for maintenance, be unfavorable for maintenance.In addition, be the vertical type coal dust corner tube boiler shown in Fig. 1 be steam boiler, its structure is also not suitable for heat conducting oil boiler of the present utility model.
The problems such as be another kind of vertical type coal dust corner tube boiler shown in Fig. 2, its secondary furnace is arranged on the rear side of burner hearth 13 ', and have flue gas flow equally short, heat exchange efficiency is lower, maintenance difficulty.
Summary of the invention
To be solved in the utility model is the existing vertical deficiency with assembling horizontal powder boiler in bulk, provides a kind of powder boiler of three novel backhauls.
For solving the problem, the utility model is by the following technical solutions: a kind of three backhaul powder boilers, comprise burner hearth, secondary furnace, convection bank, afterbody heat transmission equipment, burner, fall slag device, lower header and upper collecting chamber, described lower header is arranged on the bottom of boiler body, and described upper collecting chamber is arranged on the top of boiler body; Described burner arrangement is at the front portion of boiler furnace, top, bottom or sidepiece; It is characterized in that described boiler body adopts full film water cold wall structure, 4 main down-comers are arranged in corner; Described convection bank is arranged in convection bank flue, and described convection bank flue is longitudinally arranged, and contour with described burner hearth; The two ends up and down of described convection bank, main down-comer and fin panel casing respectively with described upper collecting chamber and lower header UNICOM; Described secondary furnace and burner hearth are back-to-back longitudinally side by side and contour setting; Described burner hearth, secondary furnace, convection bank flue and afterbody heat transmission equipment are connected conducting successively; The described slag device that falls is arranged on described burner hearth bottom; Combustion-supporting and the denitration Secondary Air of secondary is furnished with in described burner hearth.
The powder boiler of three backhauls of the present utility model, various powder fuel (containing coal dust, oil, gas, biomass powder, other flammable solid powder) sprays into airtight membrane wall burner hearth by burner, meanwhile, the high temperature air after the heating of afterbody heat transmission equipment also enters burner and powder and is mixed into burner hearth and carries out strong suspension combustion; Combustion-supporting and the denitration Secondary Air of two-stage is arranged, in the generation ensureing effectively to stop burner hearth coking under the clean-burning prerequisite of uncombusted product and reduce nitrogen oxide in burner hearth.
High-temperature flue gas after hearth combustion heat exchange from burner hearth outlet flue transfer 180 ° downwards (or upwards) enter the secondary furnace of connecting back-to-back with burner hearth, flue gas after abundant after-flame heat exchange enters convection bank again and carries out heat convection, and then flue gas enters flue gas purification system after entering afterbody heat transmission equipment again and purifies.
The utility model has the following advantages:
1) boiler body adopts cornue or pipe-support type structure to arrange, 4 main down-comers of heavy caliber are arranged in corner, and namely this main down-comer is oil circuit piping, also support whole boiler simultaneously, therefore do not need separately to establish supporting steel frame, compact overall structure, profile layout is simple, floor space is little, and steel consumption is low.
2) employing full film type wall structure, comprises burner hearth and convection bank flue all adopts membrane wall structure, and its effect is: burner hearth adopts membrane wall structure, and furnace wall only needs insulation material, integral sealing, good heat insulating, and Air Leakage Into Boilers is few, and air-introduced machine power consumption is few; Brick baffle between burner hearth and secondary furnace and convection bank flue also adopt membrane wall structure, make use of the heat of fuel combustion in burner hearth and secondary furnace fully, substantially increase heat exchanger effectiveness.
3) secondary furnace described in and burner hearth are arranged side by side back-to-back, fuel concentrated combustion, and sufficient combustion, and thus the utilization rate of fuel is high; And because the brick baffle between secondary furnace and burner hearth is membrane wall structure, and heat exchange area between secondary furnace and burner hearth is large, fully can absorb the heat of secondary furnace and burner hearth, improves heat exchange efficiency; Burner hearth, secondary furnace and convection bank longitudinally and contour setting, three's three return structures in series, the long flow path of flue gas, and time of staying in flue is also long, further increases heat exchange efficiency.
4) adopt air zoning grading combustion technology, send into two-stage Secondary Air in burner hearth, whole uniform temperature fields, effective generation stoping burner hearth coking and reduce nitrogen oxide under the clean-burning prerequisite of uncombusted product can be ensured.
As improvement of the present utility model, described burner is single or multiple burner arrangement.The benefit of single or multiple burner arrangement is that each burner can control separately, greatly improves the stability of burning and the adjusting function of load, and can use two or more fuel simultaneously.
As further improvement of the utility model, described convection bank adopts coiled pipe, and in-line arrangement.Convection heating surface adopts flag facial canal or coiled pipe, and the vertical in-line arrangement of certain angle press by coiled pipe, and heating surface is sufficient, and reliably, sweep of gases is smooth and easy, not easily dust stratification in circulation, prolonged boiler service life.
Improve further as of the present utility model, fin panel casing, convection bank, fall slag device and afterbody heat transmission equipment modular manufacturing and installation again, and efficiently solve the problem of boiler transportation clearance restriction boiler capacity development, boiler manfacturing installs simple and fast.
Improve further again as of the present utility model, between described secondary furnace and convection bank flue, be also provided with space for maintenance.Boiler is comprehensive can maintain and replace, and tool keeps in repair easy advantage.
Three backhaul powder heat conducting oil boilers of the present utility model, adopt forced circulation structure, the lower header of boiler is sent in boiler oil return from boiler oil return opening by oil circulating pump, absorb heat by convection bank heat exchange and upwards flow into boiler upper collecting chamber, upper collecting chamber enters the rising heat exchange fin panel casing of next series connection again by the main down-comer be not heated.Last deep fat sends boiler from the boiler oil-out at upper collecting chamber top, is formed and forces oil circulation.Recycle oil is all flowing of rising at high temperature heat-transfer surface, therefore, greatly improves the security of boiler oil circulation.
Further improve as of the present utility model, boiler body can also be arranged and organize false downcomer more, fin panel casing is also divided into many groups, simultaneously, upper collecting chamber and lower header are also arranged and false downcomer region one to one, are formed from one group of upper collecting chamber, fin panel casing and lower header again to the roundabout reciprocal medium flow process of next group upper collecting chamber, fin panel casing and lower header.
Accompanying drawing explanation
The utility model is described in further detail for Structure Figure and embodiment below;
Fig. 1 and Fig. 2 is the structural representation of existing vertical type coal dust corner tube boiler;
Fig. 3 is the structural representation of the first embodiment of the utility model;
Fig. 4 is the structural representation of the utility model the second embodiment;
Fig. 5 is the structural representation of the third embodiment of the utility model;
Fig. 6 is the structural representation of the utility model the 4th kind of embodiment.
In figure, 2-burner hearth, 3-secondary furnace, 4-convection bank, 5-afterbody heat transmission equipment, the main down-comer of 6-, 7-fin panel casing, 8-burner, 9-lower header, 10-secondary Secondary Air, 11-falls slag device, and 12-goes out dry (wetting) slag machine, 13-secondary furnace outlet flue, 14-burner hearth outlet flue, 15-upper collecting chamber, 16-convection bank outlet flue, 17-space for maintenance, 18-convection bank flue.
Detailed description of the invention
See figures.1.and.2, existing vertical type coal dust corner tube boiler, described before its defect, did not repeat them here.
Three backhaul powder boilers of the present utility model, are applicable to Natural Circulation or forced circulation boiler.For natural circulation boiler, can be steam boiler, also can be hot-water boiler.For forced circulation boiler, can be hot-water boiler, or heat conducting oil boiler.
With reference to Fig. 3, the first embodiment of the present utility model.Boiler body comprises oil circulating pump, burner hearth 2, secondary furnace 3, convection bank 4, afterbody heat transmission equipment 5, burner 8, the slag device 11 that falls, lower header 9 and upper collecting chamber 15, described lower header 9 is arranged on the bottom of boiler body, and described upper collecting chamber 15 is arranged on the top of boiler body; Described burner 8 is arranged in the front portion of boiler furnace; Described boiler body adopts full fin panel casing, and adopt corner tube type or pipe-support type structure, 4 main down-comers 6 are arranged in corner simultaneously; Described convection bank 4 adopts flag facial canal or coiled pipe structure, and in-line arrangement is in convection bank flue 18; Described convection bank flue 18 is longitudinally arranged, and contour with described burner hearth 2; The two ends up and down of described convection bank 4, main down-comer 6 and fin panel casing 7 respectively with described upper collecting chamber 15 and lower header 9 UNICOM; Described secondary furnace 3 and burner hearth 2 are back-to-back longitudinally side by side and contour setting; Described burner hearth 2, secondary furnace 3, convection bank flue 18 and afterbody heat transmission equipment 4 are connected conducting successively; The described slag device 11 that falls is arranged on bottom described burner hearth 2; Combustion-supporting and the denitration Secondary Air 10 of secondary is furnished with in described burner hearth 2.
In the present embodiment, described secondary furnace 3 top and burner hearth 2 outlet flue 14 UNICOM, bottom and described convection bank flue 18 UNICOM; Described convection bank 4 is arranged in the convection bank flue 18 that is made up of fin panel casing, with secondary furnace outlet flue 13 UNICOM bottom it, and top outlet flue 16 and described afterbody heat transmission equipment 5 UNICOM.
The burning of single or multiple powder combustor 8 can independently control, and burner hearth 2 top arranges explosion proof door, and middle part arranges the combustion-supporting and denitration Secondary Air 10 of secondary, and lime-ash focuses on out dry slag (or wet slag) machine 12 automatically from the slag device 11 that falls.
Described fin panel casing 7, convection bank 4, fall slag device 11 and afterbody heat transmission equipment 5 modular manufacturing and installation.Be also to be provided with space for maintenance 17 between described secondary furnace 3 and convection bank flue 18.
The operation principle of the heat conducting oil boiler of the utility model forced circulation is as follows:
Various powder fuel (containing coal dust, oil, gas, biomass powder, other flammable solid powder) sprays into membrane wall burner hearth 7 by single or multiple burner 8, meanwhile, the high temperature air after afterbody heat transmission equipment 5 heats also enters burner 8 and is mixed into burner hearth 2 with powder and carries out strong suspension combustion; And arrange the combustion-supporting and denitration Secondary Air and 10 of two-stage in burner hearth, in the generation ensureing effectively to stop burner hearth coking under the clean-burning prerequisite of uncombusted product and reduce nitrogen oxide.High-temperature flue gas after burner hearth 2 combustion heat-exchange is transferred 180 ° from burner hearth outlet flue 14 secondary furnace 3 entering downwards and connect back-to-back with burner hearth, and the flue gas after abundant after-flame heat exchange enters convection bank flue 18 again; In convection bank flue 18, the water in flue gas and convection bank 4 carries out heat convection, and the flue gas after cooling enters afterbody heat transmission equipment 5, finally enters flue gas purification system and purifies.In flue gas purification system, the solid particle in flue gas and sulfur dioxide are eliminated.The preheated air of heat absorption again sprays into burner hearth 7 from multiple burner 8.Afterbody heat transmission equipment 5 can utilize the waste heat of flue gas to carry out preheating to air, thus reaches the utilization of waste heat recovery Posterior circle and energy-conservation object.
Oil return is entered the lower header 9 of boiler from boiler oil return opening by oil circulating pump, absorb heat by convection bank 4 heat exchange and upwards flow into boiler upper collecting chamber 15, upper collecting chamber enters the rising heat exchange fin panel casing 7 of next series connection again by the main down-comer 6 be not heated.Last hot water sends boiler from the boiler delivery port at upper collecting chamber 15 top, is formed and forces oil circulation.Recycle oil is all flowing of rising at whole high temperature heat-transfer surface.Therefore, the security of boiler oil circulation is greatly improved.
Boiler body can also be arranged and organize false downcomer more, fin panel casing 7 is also divided into many groups, simultaneously, upper collecting chamber 15 and lower header 9 are also arranged and false downcomer region one to one, are formed from one group of upper collecting chamber 15, fin panel casing 7 and lower header 9 again to the roundabout reciprocal medium flow process of next group upper collecting chamber 15, fin panel casing 7 and lower header 9.
With reference to Fig. 4, the second embodiment of the present utility model.Only be that burner arrangement is at roof of the furnace with Fig. 3 embodiment difference, all the other structures are identical with Fig. 3 embodiment.
Fig. 5 is the structural representation of the third embodiment of the utility model.Only be that burner arrangement is at burner hearth bottom with Fig. 3 embodiment difference, all the other structures are identical with Fig. 1 embodiment.
Fig. 6 is the structural representation of the utility model the 4th kind of embodiment.Only be that burner arrangement to liquidate left and right sides at burner hearth with Fig. 1 embodiment difference, all the other structures are identical with Fig. 1 embodiment.
It is understood that above-described embodiment is just to explanation of the present utility model, instead of to restriction of the present utility model, any utility model do not exceeded in the utility model spirit is created, and all falls within protection domain of the present utility model.

Claims (6)

1. a backhaul powder heat conducting oil boiler, comprise oil circulating pump, burner hearth (2), secondary furnace (3), convection bank (4), afterbody heat transmission equipment (5), burner (8), the slag device (11) that falls, lower header (9) and upper collecting chamber (15), described lower header (9) is arranged on the bottom of boiler body, and described upper collecting chamber (15) is arranged on the top of boiler body; Described burner (8) is arranged in the front portion of boiler furnace, top, bottom or sidepiece; It is characterized in that described boiler body adopts full film water cold wall structure, 4 main down-comers (6) are arranged in corner; Described convection bank (4) is arranged in convection bank flue (18), and described convection bank flue (18) is longitudinally arranged, and contour with described burner hearth (2); The two ends up and down of described convection bank (4), main down-comer (6) and fin panel casing (7) respectively with described upper collecting chamber (15) and lower header (9) UNICOM; Described secondary furnace (3) and burner hearth (2) are back-to-back longitudinally side by side and contour setting; Described burner hearth (2), secondary furnace (3), convection bank flue (18) and afterbody heat transmission equipment (4) are connected conducting successively; The described slag device (11) that falls is arranged on described burner hearth (2) bottom; Combustion-supporting and the denitration Secondary Air (10) of secondary is furnished with in described burner hearth (2).
2. a kind of three backhaul powder heat conducting oil boilers as claimed in claim 1, is characterized in that described burner (8) is for single or multiple.
3. a kind of three backhaul powder heat conducting oil boilers as claimed in claim 1, is characterized in that described convection bank (4) adopts coiled pipe structure, and in-line arrangement.
4. a kind of three backhaul powder heat conducting oil boilers as claimed in claim 1, is characterized in that described fin panel casing (7), convection bank (4), fall slag device (11) and afterbody heat transmission equipment (5) modular manufacturing and installation.
5. a kind of three backhaul powder heat conducting oil boilers as claimed in claim 1, is characterized in that also being provided with space for maintenance (17) between described secondary furnace (3) and convection bank flue (18).
6. as the one three backhaul powder heat conducting oil boiler of claim 1-5 as described in any one, it is characterized in that boiler body is also arranged organizing false downcomer more, described fin panel casing (7) is also divided into many groups, meanwhile, upper collecting chamber (15) and lower header (9) also arrange multiple with false downcomer region one to one.
CN201520632604.8U 2014-10-09 2015-08-20 Three -return -stroke powder heat conduction oil boiler Expired - Fee Related CN205102403U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201520632604.8U CN205102403U (en) 2014-10-09 2015-08-20 Three -return -stroke powder heat conduction oil boiler

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CN201420580705 2014-10-09
CN2014205807050 2014-10-09
CN201520632604.8U CN205102403U (en) 2014-10-09 2015-08-20 Three -return -stroke powder heat conduction oil boiler

Publications (1)

Publication Number Publication Date
CN205102403U true CN205102403U (en) 2016-03-23

Family

ID=55518182

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201520632604.8U Expired - Fee Related CN205102403U (en) 2014-10-09 2015-08-20 Three -return -stroke powder heat conduction oil boiler

Country Status (1)

Country Link
CN (1) CN205102403U (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106052125A (en) * 2016-08-03 2016-10-26 仲伟军 Horizontal heat-conducting oil boiler

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106052125A (en) * 2016-08-03 2016-10-26 仲伟军 Horizontal heat-conducting oil boiler
CN106052125B (en) * 2016-08-03 2022-02-11 仲伟军 Horizontal heat-conducting oil boiler

Similar Documents

Publication Publication Date Title
CN104359098A (en) Three-return-stroke powder heat conduction oil boiler
CN103423869B (en) A kind of Horizontal type circulating fluid bed heat-conducting oil furnace
CN205403139U (en) Low nitrogen buggy boiler
CN102644911A (en) Vertical coal dust corner tube boiler
CN104359099A (en) Three-return-stroke powder steam boiler
CN103363517B (en) A kind of high bed temperature CFBB of 700 DEG C and above steam parameter
CN103032864A (en) Vertical coal powder corner tube boiler
CN102374658B (en) Angular pipe water circulating structure with complete forced upward flowing on heating surface
CN202598491U (en) Coal water slurry low-nitrogen rotational flow combustion boiler
CN101398169B (en) Coal-burning installation of small-sized industrial circulating fluid bed
CN204240318U (en) A kind of three backhaul powder steam boilers
CN205102403U (en) Three -return -stroke powder heat conduction oil boiler
CN202902245U (en) Upright-type coal powder corner-tube boiler
CN201670735U (en) Efficient heat-recovering decarburization roasting boiler with low calorific value
CN204240339U (en) A kind of three backhaul powder hot-water boilers
CN203432081U (en) Thermal conduction oil furnace for horizontal type circulating fluidized bed
CN203203006U (en) Upright pulverized coal corner tube type boiler
CN105485894A (en) Pulverized coal type water heating boiler
CN203147726U (en) Pi-structural catalytic unit CO incineration waste heat boiler
CN202254307U (en) Corner tube water circulation structure
CN103134036A (en) Vertical type modular coal water slurry corner tube boiler
CN103062747A (en) Vertical type coal dust corner tube boiler
CN102889585A (en) Environment-friendly energy-saving vertical boiling boiler
CN203203009U (en) Vertical modularized coal water slurry corner tube boiler
CN209180921U (en) Biomass direct-fired hot-water boiler

Legal Events

Date Code Title Description
C14 Grant of patent or utility model
GR01 Patent grant
CP01 Change in the name or title of a patent holder

Address after: Hangzhou City, Zhejiang province 311115 Fengdu Pingyao Town, Yuhang District Industrial Zone Road, Yangcheng Road No. 1

Patentee after: HANGZHOU JUNENG ENVIRONMENTAL PROTECTION TECHNOLOGY CO.,LTD.

Address before: Hangzhou City, Zhejiang province 311115 Fengdu Pingyao Town, Yuhang District Industrial Zone Road, Yangcheng Road No. 1

Patentee before: HANGZHOU JUNENG BOILER Co.,Ltd.

CP01 Change in the name or title of a patent holder
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20160323

CF01 Termination of patent right due to non-payment of annual fee