CN105484499B - Concrete pumping pipe method for cleaning and device - Google Patents
Concrete pumping pipe method for cleaning and device Download PDFInfo
- Publication number
- CN105484499B CN105484499B CN201510935672.6A CN201510935672A CN105484499B CN 105484499 B CN105484499 B CN 105484499B CN 201510935672 A CN201510935672 A CN 201510935672A CN 105484499 B CN105484499 B CN 105484499B
- Authority
- CN
- China
- Prior art keywords
- concrete
- pumping
- ice cube
- hopper
- ice
- 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
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/02—Conveying or working-up concrete or similar masses able to be heaped or cast
Abstract
The present invention relates to concrete duct transportation art, specifically a kind of concrete pumping pipe method for cleaning and device；Including having the following steps：After depositing concrete terminates, continue to deliver the mixture of ice cube and Sorbet into hopper, push mixture and ensure that it is pumped machine suction after concrete pumping terminates；Continue to add ice cube and water into the hopper of pumping machine, the volume of ice cube is no more than the volume of 1000mm pumping lines；Continue to add enough water into pumping machine hopper to promote ice cube and concrete to advance, until the concrete in pumping line is all released；Close pumping machine, keep pumping line in water, to pump concrete next time before discharge；Using the concrete pumping pipe method for cleaning of technical solution of the present invention, use cost is low, without removing pipeline, and will not block.
Description
Technical field
The present invention relates to concrete duct transportation art, specifically a kind of concrete pumping pipe method for cleaning and dress
Put.
Background technology
Concrete is conventional construction material, after mixing plant production, delivers to place to use by transporting equipment, then
Pumping line is pressed into by pumping machine, construction location is then transported to by pumping line, when concrete conveyance finishes it
Afterwards, it usually needs remaining concrete in cleaning pumping line, in order to avoid blocking pipeline after concrete setting.
Traditional method for cleaning has two kinds, and a kind of is directly to be pumped into the concrete that water is rinsed in pumping line by pumping machine,
Cement therein is rinsed out, the bottom of pumping machine is then taken apart, the aggregates such as the sandstone reserved in pumping line are discharged, this side
Method is typically only applicable to the construction of short floor, because after story height, in pumping line remaining concrete is more, on the one hand
Directly rinse and cause larger waste, it is often more important that can produce substantial amounts of stone and sand, particularly high level after directly rinsing and apply
Pumping line has more elbow again in work, easily causes the blocking of pumping line, can only merogenesis dismounting, cleaning once blocking
Reinstall again, workload is very big, therefore water flushing can not typically use the pumping line cleaning of high level；Another cleaning
Method is to promote rotating wash bowl to carry out pipeline cleaning using air compressor, and specific practice is：After pump concrete terminates, tear open first
One except bottom saves concrete delivery pump pipe, is quickly put into a sponge ball or cloth group, pumping line then is connected into sky again
On air compressor, air compressor promotes rotating wash bowl that concrete is all discharged into pumping line.The benefit of this method for cleaning is
Can preferably avoid the waste of concrete, but there are still more shortcoming, specifically at least include it is following some：1,
Need individually to be equipped with a set of air compressor, use cost is very high；Many concrete streams can be caused when the 2nd, removing pumping line
Go out, not only waste but also construction environment can be polluted；3rd, sponge ball or cloth group are particularly easy to block in pumping line, particularly exist
Pipe joint or turning position, once blocking, it is necessary to substantial amounts of manpower and materials check blocking position, then remove pipe
Road is cleared up, and the process of cleaning can occur concrete and waste and pollute again, could take over again afterwards, fairly cumbersome.
For synthesis, also lack that a kind of input is low at present, the construction method of the good cleaning concrete pumping pipe of effect and
Special purpose device.
The content of the invention
An object of the present invention is to provide a kind of use cost low, without removing pipeline, and will not block
Pumping line concrete method for cleaning；Another purpose of the application is to provide a kind of conversion dress coordinated with the above method
Put.
To achieve these goals, the present invention provides a kind of concrete pumping pipe method for cleaning, including has the following steps：
A, after into the hopper of pumping machine, depositing concrete terminates, continues to deliver the mixing of ice cube and Sorbet into hopper
Thing, mixture is covered in concrete upper surface, pushes mixture and ensures that it is pumped machine suction after concrete pumping terminates；
B, continues to add ice cube and water into the hopper of pumping machine, the volume of ice cube is no more than 1000mm pumping lines
Volume；
C, continues to add enough water into pumping machine hopper to promote ice cube and concrete to advance, until pumping line
In concrete all released；
D, close pumping machine, keep pumping line in water, to pump concrete next time before discharge.
Sorbet described in text is the less trash ice bits of particle, and main function plays isolation water and concrete well
Effect.
Had the following advantages using above method cleaning concrete pumping pipe：Concrete pumping in hopper is completed
When, the mixture in step A is then pumped machine and is sent to pumping line, and this part mixes can be as a deformable cloth
Group or sponge ball, can be good at isolation concrete but without blocking；Follow the ice cube and water in the step B of addition closely
Into pumping line, the effect of water here is in order to ensure that ice cube is pumped machine suction, due to the buffer action of mixture, step
B water can not be flushed to the water being pumped into concrete, later step C and persistently promote ice cube, mixture and concrete to advance, by
It is less than water in the density of ice cube, it can rapidly be gathered in the lower section of mixture, and collectively form concrete and water with mixture
Distance piece, it is to avoid flushing of the water to concrete, therefore segregation phenomenon will not occur for coarse aggregate and fine aggregate in concrete；Work as warp
When crossing joint or bend pipe, due to ice cube surface unusual light and can be with breaking deformation, therefore it will not block, pumping procedure
In the ice cube that is contacted with tube wall can occur a small amount of abrasion and thawing, lubrication, a small amount of Sorbet and ice cube can be played a part of
Loss does not influence the buffer action of distance piece.
Compared to traditional backwashing manner that directly adds water, it can be applied to the pumping of short floor and super-high storied building simultaneously
Pipeline cleaning, will not occur the isolation plugging phenomenon of concrete；Compared to the mode that conventional air compressor promotes sponge ball,
It eliminates the input of air compressor, and cost is very low, and should not tear pipe open and be put into sponge ball, using more convenient, most attaches most importance to
What is wanted is that it is effectively utilized that ice cube surface is smooth, can extrude broken characteristic, forms a point for effectively substituting sponge ball
Compartment, isolation performance is especially good, and small with the frictional force of tube wall, run into joint or elbow, bend pipe be very easy to deformation around
Cross, will not block, it is not necessary to dismantle pumping line, be both changed into water after thawing, cost is low, pipeline will not be polluted, step D
The water of middle preservation can play a part of moistening pipe agent, next time before pump concrete, and bleeding off after water just can direct pumped concrete
Soil, has saved engineering time and the cost of profit pipe agent.
Preferably, the cumulative volume of the step A mixtures is not more than the volume of 500mm pumping lines, wherein ice
Husky cumulative volume is not less than the cumulative volume of ice cube, and such benefit is that Sorbet can effectively fill up the gap of ice cube, is formed with
The concrete isolation of effect, the effect of ice cube is that its thawing speed is slower compared to Sorbet, and isolation time is effectively ensured.
Preferably, the volume of step A, the B medium floe is no more than the 1.3 of concrete coarse aggregate maximum volume
Times, it is such be advantageous in that can both avoid it is poor compared with the isolation effect that berg is caused, can avoid again promotion the concrete phase
Between melt too small, cause separation force not enough.
Preferably, step A, the B medium floe is shaped as spherical, box-shaped or prismatic, these three shapes
The ice cube processing cost of shape is relatively low, and structural strength is preferably, can preferably avoid crushing.
Preferably, use reticular lamina to push ice cube in the step B to ensure that ice cube is preferentially sucked pumping machine.
In order to realize such scheme, the application provides a kind of special device simultaneously, includes hopper, and the bottom of hopper is set
Be equipped with around the suction inlet of pumping machine, suction inlet be connected with vertically arranged cylinder enter ice cylinder, this enter ice cylinder lower sides
Inlet opening is provided with, enters in ice cylinder and the poroid pressing plate for promoting ice cube is set, the poroid pressing plate is by two pieces of semicircles being diametrically hinged
Plate and the cross bracket composition for being supported on semicircle postlaminar part, the hinged place of semi-circular plate is fixed to a bar of cross bracket
On, cross bracket overcentre is fixed with pressing plate bar, and the top of pressing plate bar, which is arranged with to be fixed on into the center of ice cylinder upper end, determines
Position support, the upper end of pressing plate bar is fixed to by elastic tension apparatus on the side wall of hopper.
There are following features using the special purpose device of technical solution of the present invention：At the end of concrete pumping is fast, ice will be entered
Cylinder is placed into above the suction inlet of pumping machine, and ice cube and ice cube and the mixture of Sorbet can be pre-placed by entering in ice cylinder, wherein
The mixture of ice cube and Sorbet is located at into the bottom of ice cylinder, and the power of elastic tension apparatus passes to semi-circular plate, two by pressing plate bar
Individual semi-circular plate composition piston promotes mixture and ice cube to enter pumping line, it is necessary to when on the rocks, it is only necessary to pressing plate bar of pulling back,
Added from ice cylinder top is entered, ice cube passes through the semi-circular plate being hinged to enter ice cylinder, unclamp pressing plate bar, ice cube is just in elasticity drawing
Moved in the presence of tight device to pumping machine, enter the inlet opening of ice cylinder bottom mainly for water can enter the gap of ice, pressing plate
On hole be in order to which water can be directly entered the suction inlet of pumping machine through the hole on pressing plate after ice has been pushed.
Preferably, the take-up device is elastic rubber band or extension spring, and such setting can both ensure to make
With effect, use cost can be reduced by having.
Preferably, the take-up device right-angled intersection is set, force that so can be averagely, it is to avoid pressing plate bar and
Semi-circular plate receives larger resistance.
Brief description of the drawings
Fig. 1 for the embodiment of the present invention pumping line in distance piece structural representation（Size only presents a demonstration with length）；
Fig. 2 is the structural representation of the special purpose device of the embodiment of the present invention.
Wherein, hopper 1, suction inlet 2, enter ice cylinder 3, inlet opening 4, semi-circular plate 5, cross bracket 6, pressing plate bar 7, center is fixed
Position support 8, elastic rubber band 9, protective layer 11, mixture 12, concrete 13, water 14.
Embodiment
With reference to the accompanying drawings and detailed description to being described in further detail：
As depicted in figs. 1 and 2：The present invention provides a kind of concrete pumping pipe method for cleaning and special device,
Special purpose device includes：Hopper 1, the bottom of hopper 1, which is provided with around the suction inlet 2 of pumping machine, suction inlet 2, to be connected with
Vertical cylinder enters ice cylinder 3, enters the material preferably stainless steel structure of ice cylinder 3, and outer wall can add garter spring, enters under ice cylinder 3
Portion side wall is provided with inlet opening 4, and the size of inlet opening 4 should ensure that ice cube will not be extruded, therefore the diameter of inlet opening is typically kept
In 2~5mm, the preferred 3mm of the application enters in ice cylinder 3 and sets the poroid pressing plate for promoting ice cube, the poroid pressing plate is by two pieces of edges
Semi-circular plate 5 that diameter is hinged and it is supported on the cross bracket 6 at the rear portion of semi-circular plate 5 and constitutes, the hinged place of semi-circular plate 5 is provided with
Its torsion spring opened is kept, and the axle being hinged is fixed on wherein one bar of cross bracket 6, on the center of cross bracket 6
Side is fixed with pressing plate bar 7, and the top of pressing plate bar 7 is arranged with the centralized positioning support 8 being fixed on into 3 upper ends of ice cylinder, pressing plate bar 7
Upper end is fixed on the side wall of hopper 1 by two elastic rubber bands 9 of right-angled intersection, and elastic rubber band 9 can also be replaced with
Extension spring, the height of pressing plate bar 7 should be higher than that the side wall of hopper 1.
Concrete pumping pipe method for cleaning includes the steps：
A, when the concrete in pumping machine hopper 1 pumps completion soon, will enter the suction inlet 2 that ice cylinder 3 is placed into pumping machine
Top, and elastic rubber band 9 is fixed rapidly to the side wall of hopper 1, enter the mixing that ice cube and Sorbet are pre-placed in ice cylinder 3
Thing, elastic rubber band 9 drives two composition pistons of semi-circular plate 5 to promote mixture to ensure that it is pumped machine and sucks and send into pumping line
Road, the cumulative volume that mixture is added is not more than the volume of 500mm pumping lines, and the volume of 450mm pumping lines is selected herein, its
Middle Sorbet of the total volume 60%, the maximum length of Sorbet is no more than 1mm, and the maximum length of ice cube is generally no greater than 20mm, minimum
Size is not also less than 10mm, in order to avoid melt or broken；
Mixture in B, step A and send it is fast at the end of, pressing plate bar 7 of pulling back, from the top ice cube for entering ice cylinder 3, ice cube is worn
Cross the semi-circular plate 5 being hinged and enter ice cylinder 3, and water is added entering the outside of ice cylinder 3, the volume of ice cube is no more than 1000mm pumping lines
The volume in road, selects 900mm herein, in order that obtain on the rocks easier, can also be by the ice cube in step B in step A
It is charged first into above the mixture in ice cylinder 3, the ice cube volume only added is not enough the addition ice cube of pressing plate bar 7 of just pulling back,
The maximum length of its medium floe is generally no greater than 20mm, and minimum dimension is not also less than 10mm, in order to avoid melt or broken；
C, when enter ice cylinder 3 in ice cube pump completion substantially when, continue to add enough water into pumping machine hopper 1 to push away
Dynamic ice cube and concrete are moved on, until the concrete in pumping line is all released；
D, close pumping machine, keep pumping line in water, to pump concrete next time before discharge.
Above method cleaning concrete pumping pipe tool is performed such：Mixture in step A is pumped machine feeding
To after pumping line, this part mixes 12 can promote concrete well as a deformable cloth group or sponge ball
13 and pumping line inwall is cleared up, because Sorbet is fine and smooth, therefore closure isolation effect is very well, simultaneously because Sorbet and ice cube are very
It is smooth, and be easily deformed, therefore will not block；The ice cube followed closely in the step B of addition enters after pumping line with water, can
To obstruct impact of the water being persistently pumped into step C to Sorbet, therefore the density of ice cube is less than water, and it is after pumping line is entered
It can rapidly be gathered in the lower section of mixture 12, form the protective layer 11 for avoiding water slug, and collectively form with mixture 12 mixed
The distance piece of solidifying soil 13 and water 14, it is to avoid the water being continually fed into is direct to concrete to be rinsed, and is prevented effectively from the isolation of concrete 13 stifled
Pipe phenomenon；When by joint or bend pipe, due to ice cube surface unusual light and can be with breaking deformation, therefore will not also occur
Block, with Sorbet a small amount of abrasion and thawing can occur in pumping procedure for ice cube, and this aspect can play a part of lubrication, separately
Outside because the volume of distance piece is larger, a small amount of loss does not interfere with the buffer action of distance piece yet.
Ice cube is shaped as generally preferably spherical, box-shaped or prismatic, using spherical in the application.
Described above is only the preferred embodiment of the present invention, wherein the general knowledge such as known concrete structure and characteristic is herein not
Make excessive description.It should be pointed out that for those skilled in the art, not departing from the premise of structures and methods of the present invention
Under, several modifications and improvements can also be made, these should also be considered as protection scope of the present invention, these are all without this hair of influence
The effect and practical applicability of bright implementation.
Claims (8)
1. a kind of concrete pumping pipe method for cleaning, it is characterised in that including having the following steps：
A, after depositing concrete terminates into the hopper of pumping machine, continues to deliver the mixture of ice cube and Sorbet into hopper, mixes
Compound is covered in concrete upper surface, pushes mixture and ensures that it is pumped machine suction after concrete pumping terminates；
B, continues to add ice cube and water into the hopper of pumping machine, the volume of ice cube is no more than the volume of 1000mm pumping lines；
C, continues to add enough water into pumping machine hopper to promote ice cube and concrete to advance, until mixed in pumping line
Solidifying soil is all released；
D, close pumping machine, keep pumping line in water, to pump concrete next time before discharge.
2. concrete pumping pipe method for cleaning according to claim 1, it is characterised in that：The step A mixtures
Cumulative volume is not more than the volume of 500mm pumping lines, and the wherein cumulative volume of Sorbet is not less than the cumulative volume of ice cube.
3. concrete pumping pipe method for cleaning according to claim 1, it is characterised in that：Step A, the B medium floe
Volume be no more than 1.3 times of concrete coarse aggregate maximum volume.
4. concrete pumping pipe method for cleaning according to claim 1, it is characterised in that：Step A, the B medium floe
Be shaped as spherical, box-shaped or prismatic.
5. concrete pumping pipe method for cleaning according to claim 1, it is characterised in that：Net is used in the step B
Shape plate pushes ice cube to ensure that ice cube is preferentially sucked pumping machine.
6. a kind of device for being exclusively used in claim 1 method for cleaning, it is characterised in that：Include hopper, the bottom of hopper is set
Have be connected with around the suction inlet of pumping machine, suction inlet vertically arranged cylinder enter ice cylinder, this enter ice cylinder lower sides set
Inlet opening is equipped with, enters in ice cylinder and the poroid pressing plate for promoting ice cube is set, the poroid pressing plate is by two pieces of semi-circular plates being diametrically hinged
And the cross bracket composition of semicircle postlaminar part is supported on, the hinged place of semi-circular plate is fixed to a bar of cross bracket
On, cross bracket overcentre is fixed with pressing plate bar, and the top of pressing plate bar, which is arranged with to be fixed on into the center of ice cylinder upper end, determines
Position support, the upper end of pressing plate bar is fixed to by elastic tension apparatus on the side wall of hopper.
7. device as claimed in claim 6, it is characterised in that：The take-up device is elastic rubber band or extension spring.
8. device as claimed in claim 6, it is characterised in that：The take-up device right-angled intersection is set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510935672.6A CN105484499B (en) | 2015-12-15 | 2015-12-15 | Concrete pumping pipe method for cleaning and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510935672.6A CN105484499B (en) | 2015-12-15 | 2015-12-15 | Concrete pumping pipe method for cleaning and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105484499A CN105484499A (en) | 2016-04-13 |
| CN105484499B true CN105484499B (en) | 2017-10-31 |
Family
ID=55671747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510935672.6A Expired - Fee Related CN105484499B (en) | 2015-12-15 | 2015-12-15 | Concrete pumping pipe method for cleaning and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105484499B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6175890U (en) * | 1984-10-19 | 1986-05-22 | ||
| CN203002716U (en) * | 2012-12-27 | 2013-06-19 | 江西昌南建设集团有限公司 | High level concrete pumping pipeline cleaning assembly |
| CN103321426A (en) * | 2013-06-27 | 2013-09-25 | 中国新兴建设开发总公司 | Pumping concrete cleaning divider and application method thereof |
| CN204769768U (en) * | 2015-07-07 | 2015-11-18 | 中兴建设有限公司 | Concrete feeding is belt cleaning device for pipeline |
-
2015
- 2015-12-15 CN CN201510935672.6A patent/CN105484499B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6175890U (en) * | 1984-10-19 | 1986-05-22 | ||
| CN203002716U (en) * | 2012-12-27 | 2013-06-19 | 江西昌南建设集团有限公司 | High level concrete pumping pipeline cleaning assembly |
| CN103321426A (en) * | 2013-06-27 | 2013-09-25 | 中国新兴建设开发总公司 | Pumping concrete cleaning divider and application method thereof |
| CN204769768U (en) * | 2015-07-07 | 2015-11-18 | 中兴建设有限公司 | Concrete feeding is belt cleaning device for pipeline |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105484499A (en) | 2016-04-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100575642C (en) | Special fine sand high-strength high-performance concrete ultra-high pumping construction method | |
| CN101054854A (en) | Construction method of quick roughening of concrete | |
| CN114214906B (en) | Road construction pretreatment device and construction method thereof | |
| CN103147767A (en) | Monolithic concrete guniting device | |
| CN105484499B (en) | Concrete pumping pipe method for cleaning and device | |
| CN109610842A (en) | A kind of concrete jacking pump send construction method | |
| CN201173134Y (en) | Cemented filling device | |
| CN211640481U (en) | Concrete waste material scraping device | |
| CN103977991B (en) | System for cleaning concrete conveying pump pipe | |
| CN109079994A (en) | The production method of prefabricated ladder step | |
| JPH06264449A (en) | Spraying work of mortar or concrete | |
| JP2974654B2 (en) | Construction method using mortar and concrete mixed with steel fiber | |
| WO2016095755A1 (en) | Structure of building floor backfill spacer | |
| CN207373459U (en) | Subway engineering concrete mixer | |
| JP4551159B2 (en) | Mortar or concrete spraying method | |
| CN205558923U (en) | A unloading pipe for deep tunnel construction | |
| CN204751321U (en) | Pneumatic spiral automatic feed device of patching machine | |
| CN205588475U (en) | Cement mixing device for building | |
| CN202882453U (en) | Jointing device for bricklaying | |
| AT504092B1 (en) | METHOD AND APPARATUS FOR PUMPING MORTAR FOR ITS FILLING OR COMPOSITION | |
| JP2008296470A (en) | Manufacturing method of centrifugal casting concrete product | |
| CN216893619U (en) | UHPC reinforcing equipment of underground cavern | |
| CN207432482U (en) | A kind of fiber concrete agitating device | |
| CN102139513A (en) | Novel compound die distributing system with vibrating platform and method | |
| CN211636814U (en) | Large-particle-size stone crushing device for premixed concrete production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB03 | Change of inventor or designer information |
Inventor after: Wu Rui Inventor after: Lei Chengliang Inventor after: Chen Jing Inventor after: Shi Congli Inventor after: Zhu Feng Inventor before: Zhu Lanyu Inventor before: Zhu Feng Inventor before: Li Yuan |
|
| CB03 | Change of inventor or designer information | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20170922 Address after: 401121 A building, California Lily Garden, 1889 Longhua Avenue, Longxi street, Chongqing, Yubei District, 30-1 Applicant after: CHONGQING JIZHI CHUANGXIANG INDUSTRIAL DESIGN Co.,Ltd. Applicant after: CHONGQING CONSTRUCTION ENGINEERING BUILDING MATERIALS & LOGISTICS CO.,LTD. Applicant after: CHONGQING CONSTRUCTION ENGINEERING GROUP Co.,Ltd. Address before: 401121 A building, California Lily Garden, 1889 Longhua Avenue, Longxi street, Chongqing, Yubei District, 30-1 Applicant before: CHONGQING JIZHI CHUANGXIANG INDUSTRIAL DESIGN Co.,Ltd. |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171031 Termination date: 20211215 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |