CN106422935A - Mixing device for chemical equipment - Google Patents

Mixing device for chemical equipment Download PDF

Info

Publication number
CN106422935A
CN106422935A CN201610900626.7A CN201610900626A CN106422935A CN 106422935 A CN106422935 A CN 106422935A CN 201610900626 A CN201610900626 A CN 201610900626A CN 106422935 A CN106422935 A CN 106422935A
Authority
CN
China
Prior art keywords
fixedly connected
blending bin
motor
inwall
elongated piece
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.)
Pending
Application number
CN201610900626.7A
Other languages
Chinese (zh)
Inventor
杜旭升
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.)
Wuxi Risheng Chemical Co Ltd
Original Assignee
Wuxi Risheng Chemical 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
Application filed by Wuxi Risheng Chemical Co Ltd filed Critical Wuxi Risheng Chemical Co Ltd
Priority to CN201610900626.7A priority Critical patent/CN106422935A/en
Publication of CN106422935A publication Critical patent/CN106422935A/en
Pending legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00Other mixers; Mixing plants; Combinations of mixers
    • B01F33/80Mixing plants; Combinations of mixers
    • B01F33/82Combinations of dissimilar mixers
    • B01F33/822Combinations of dissimilar mixers with moving and non-moving stirring devices in the same receptacle
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/30Driving arrangements; Transmissions; Couplings; Brakes
    • B01F2035/35Use of other general mechanical engineering elements in mixing devices
    • B01F2035/352Bearings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2101/00Mixing characterised by the nature of the mixed materials or by the application field
    • B01F2101/2204Mixing chemical components in generals in order to improve chemical treatment or reactions, independently from the specific application
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/60Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis
    • B01F27/72Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis with helices or sections of helices

Abstract

The invention discloses a mixing device for chemical equipment. The mixing device comprises a base, wherein an engine bed and a mixing tank are successively arranged at the top of the base from left to right; a first motor is fixedly connected with the top of the engine bed; an output shaft of the first motor is fixedly connected with a rotating shaft through a coupler; and one end of the rotating shaft away from the first motor penetrates through the mixing tank, extends into the mixing tank and is in rotating connection with a bearing arranged on an inner wall of the mixing tank. In the mixing device for chemical equipment, the first motor and the second motor are arranged, and the rotating shaft is driven to rotate by the first motor, so that the effects of stirring and mixing chemical materials in the mixing tank are achieved, and the uniform stirring effect is achieved; and under the action of the second motor, a gear is driven to rotate by the output shaft of the second motor, a rack is moved left and right by the rotation of the gear, and under the effect of rack acting and moving, a folding arm is driven to stretch by a sliding rod, so that the effect of moving a stirring blade is achieved.

Description

A kind of mixing arrangement for chemical industry equipment
Technical field
The present invention relates to esterifying liquid processing technique field, specially a kind of mixing arrangement for chemical industry equipment.
Background technology
Chemical industry equipment is primarily referred to as the blower fan of fluid conveying, compressor, the equipment such as various pumps, and its critical piece is fortune Dynamic machinery, commonly referred to as chemical machine.Chemical machinery is not very strict with the division of other machineries, more for example, be used for changing The pump of work process, and the common apparatus that other industrial departments are adopted.Equally in chemical process, chemical machine and chemical industry set Also without strict differentiation between standby.Such as some reactors machine also usually equipped with motion.
In chemical industry, it is often necessary to which some materials are uniformly mixed, it is ensured that the use of chemical substance, for some The mixing of high-viscosity material, it usually needs mixer, but existing mixer complex structure and operating difficultiess, in mixing Be extremely difficult to the mixing effect to chemical substance, stirring uneven, cause material melting concn deviation occur, impact is using effect Really.
Content of the invention
(One)The technical problem of solution
For the deficiencies in the prior art, the invention provides a kind of mixing arrangement for chemical industry equipment, is difficult when solving conjunction The mixing effect to chemical substance is reached, stirs uneven problem.
(Two)Technical scheme
For realizing object above, the present invention is achieved by the following technical programs:A kind of mixing arrangement for chemical industry equipment, Including base, the top of the base is sequentially provided with support and blending bin from left to right, and the top of the support is fixedly connected with First motor, the output shaft of first motor is fixedly connected with rotary shaft by shaft coupling, and the rotary shaft is away from the first electricity One end of machine through blending bin and extends to the bearing that the inside of blending bin is provided with mixing chamber interior wall and rotates and be connected, the rotation Rotating shaft is located at the surface loop inside blending bin and is arranged with helical blade, and the side of the blending bin is through feed hopper is provided with, described The top of blending bin is fixedly connected with cushion pad, and the top of the cushion pad is fixedly connected with the second motor, second motor Output shaft on be fixedly connected with gear, the inwall top of the blending bin both sides is fixedly connected with elongated piece, described elongated piece Inwall bottom be fixedly connected with slide rail, be fixedly connected by slide bar between two described elongated piece, and the two ends of slide bar be respectively Through elongated piece and extend to elongated piece of inside and slide rail is slidably connected, described elongated piece of inwall side is fixedly connected with Determine block, the fixed block is fixedly connected with folding arm away from the side of elongated piece of inwall, the folding arm is away from the one of fixed block End is fixedly connected with the slide bar for extending to elongated piece of inside, and the middle part upper end of the slide bar is fixedly connected with vertical rod, the vertical rod Top through the top of blending bin and extend to the outside of blending bin and be fixedly connected with the tooth bar being located above blending bin, described The teeth of tooth bar are engaged with the teeth of gear, and the middle part bottom of the vertical rod is fixedly connected with puddler, and the both sides of puddler Stirring vane is fixedly connected with, the opposite side of the blending bin is fixedly connected with controller, the opposite side of the blending bin and position In the lower section of controller through discharge nozzle is provided with, the controller is electrically connected with the first motor and the second motor respectively.
Preferably, the middle part of the mixing chamber interior wall both sides is fixedly connected with swash plate, and the inwall of swash plate and blending bin it Between be in 40 degree of angles.
Preferably, the top of the blending bin offers the notch for vertical rod movement, and the length of notch is less than slide rail Length.
Preferably, the bearing includes outer ring and inner ring, and inner ring is located at the inside of outer ring, between the outer ring and inner ring Leave in gap, and gap and ball is inlaid with, on the inwall of the inner ring, be fixedly connected with Anti-slip cover.
Preferably, on the discharge nozzle, manually-operated gate is provided with.
(Three)Beneficial effect
The invention provides a kind of mixing arrangement for chemical industry equipment.Possesses following beneficial effect:This is used for chemical industry equipment Mixing arrangement, simple structure and easy to operate, by the setting to the first motor and the second motor, the first motor drives rotary shaft Rotation, is stirred, to chemical substance, the effect for mixing in blending bin, reaches the effect for stirring, by the second motor In the presence of, the output shaft of the second motor drives pinion rotation, and tooth bar is moved left and right by gear rotation, is moved in tooth bar effect Under dynamic effect, slide rail in elongated piece, slide bar, fixed block and in the presence of folding arm, slide bar Foldable arm stretches, and reaches Effect to stirring vane movement, improves mixing efficiency to material further, improves the concentration between material, it is ensured that use When possess the distinctive effect of product.
Description of the drawings
Fig. 1 is schematic structural view of the invention;
Fig. 2 is the top view of present configuration;
Fig. 3 is the internal structure schematic diagram of elongated piece of the present invention;
Fig. 4 is the structural representation of bearing of the present invention.
In figure:1 base, 2 supports, 3 blending bins, 4 first motors, 5 rotary shafts, 6 bearings, 61 outer rings, 62 inner rings, 63 rollings Pearl, 64 Anti-slip covers, 7 helical blades, 8 cushion pads, 9 second motors, 10 gears, 11 elongated pieces, 12 slide rails, 13 slide bars, 14 fix Block, 15 fold arms, 16 vertical rods, 17 tooth bars, 18 puddlers, 19 stirring vanes, 20 controllers, 21 discharge nozzles, 22 swash plates, 23 manual Valve.
Specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation is described, it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments.It is based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made Embodiment, belongs to the scope of protection of the invention.
Fig. 1-4 are referred to, the present invention provides a kind of technical scheme:A kind of mixing arrangement for chemical industry equipment, the bottom of including Seat 1, the top of base 1 is sequentially provided with support 2 and blending bin 3 from left to right, and the middle part of 3 inwall both sides of blending bin is fixedly connected with It is in 40 degree of angles between swash plate 22, and the inwall of swash plate 22 and blending bin 3, the setting of swash plate 22, it is easy to material in stirring Buffered, the top of support 2 is fixedly connected with the first motor 4, and the output shaft of the first motor 4 is fixedly connected with by shaft coupling Rotary shaft 5, rotary shaft 5 and is extended in the inside of blending bin 3 and blending bin 3 through blending bin 3 away from one end of the first motor 4 The bearing 6 that wall is provided with rotates connection, and bearing 6 includes outer ring 61 and inner ring 62, and inner ring 62 is located at the inside of outer ring 61, outer ring Leave between 61 and inner ring 62 in gap, and gap and ball 63 be inlaid with, Anti-slip cover 64 on the inwall of inner ring 62, is fixedly connected with, Rotary shaft 5 is located at the surface loop inside blending bin 3 and is arranged with helical blade 7, and the side of blending bin 3 is mixed through feed hopper is provided with The top of mould assembling 3 is fixedly connected with cushion pad 8, and cushion pad 8 reaches the effect of buffering, cushion pad 8 when the second motor 9 works Top be fixedly connected with the second motor 9, be fixedly connected with gear 10 on the output shaft of the second motor 9,3 both sides of blending bin interior Wall top is fixedly connected with elongated piece 11, and elongated piece 11 of inwall bottom is fixedly connected with slide rail 12, between two elongated piece 11 It is fixedly connected by slide bar 13, and the two ends of slide bar 13 extends through elongated piece 11 and extend to elongated piece 11 of inside and slide rail 12 are slidably connected, and elongated piece 11 of inwall side is fixedly connected with fixed block 14, and fixed block 14 is away from the one of elongated piece of 11 inwalls Side is fixedly connected with folding arm 15, folds arm 15 and plays the effect of folding retractable, fold arm 15 away from fixed block 14 one end with Extend to the slide bar 13 inside elongated piece 11 to be fixedly connected, the middle part upper end of slide bar 13 is fixedly connected with vertical rod 16, blending bin 3 Top offers the notch for moving for vertical rod 16, and the length of notch, less than the length of slide rail 12, the top of vertical rod 16 is through mixed The top of mould assembling 3 is simultaneously extended to the outside of blending bin 3 and is fixedly connected with the tooth bar 17 of 3 tops that are located at blending bin, the tooth of tooth bar 17 Tooth is engaged with the teeth of gear 10, and the middle part bottom of vertical rod 16 is fixedly connected with puddler 18, and the both sides of puddler 18 are fixed It is connected with stirring vane 19, the opposite side of blending bin 3 is fixedly connected with controller 20, the opposite side of blending bin 3 and is located at control The lower section of device 20 is provided with manually-operated gate 23 through discharge nozzle 21 is provided with discharge nozzle 21, manually-operated gate 23 is in blending bin 3 After material is mixed, open manually-operated gate 23, by the material for mixing release, controller 20 respectively with the first motor 4 and second Motor 9 is electrically connected with.
During work, the switch of the first motor 4 and the second motor 9 is opened by controller 20, then material from feed hopper Put in blending bin 3, the first motor 4 is rotated axle 5 and rotates, and material is stirred;While the output shaft band of the second motor 9 Tooth bar 17 is moved left and right by moving gear 10, and slide bar 13 is driven by the vertical rod 16 of 17 bottom of tooth bar, and slide bar 13 is moved in slide rail 12, And fold arm 15 to stretch, puddler 18 is moved left and right, drive stirring vane 19 to swing, mixing is carried out to material and is stirred Mix.
In sum, this is used for the mixing arrangement of chemical industry equipment, simple structure and easy to operate, by the first motor 4 With the setting of the second motor 9, the first motor 4 is rotated axle 5 and rotates, and is stirred mixing to chemical substance in blending bin 3 Effect, reach the effect for stirring, in the presence of to the second motor 9, the output shaft driven gear 10 of the second motor 9 Rotating, gear 10 rotates and tooth bar 17 is moved left and right, the slide rail under the effect of movement, in elongated piece 11 is acted in tooth bar 17 12nd, in the presence of slide bar 13, fixed block 14 and folding arm 15,13 Foldable arm 15 of slide bar stretches, and has reached to stirring vane The effect of 19 movements, improves the mixing efficiency to material further, improves the concentration between material, it is ensured that possess product during use Distinctive effect.
Although an embodiment of the present invention has been shown and described, for the ordinary skill in the art, permissible Understanding can carry out multiple changes, modification, replacement to these embodiments without departing from the principles and spirit of the present invention And modification, the scope of the present invention be defined by the appended.

Claims (5)

1. a kind of mixing arrangement for chemical industry equipment, including base(1), the base(1)Top set successively from left to right Organic block(2)And blending bin(3), it is characterised in that:The support(2)Top be fixedly connected with the first motor(4), described One motor(4)Output shaft rotary shaft is fixedly connected with by shaft coupling(5), the rotary shaft(5)Away from the first motor(4)'s Blending bin is run through in one end(3)And extend to blending bin(3)Inside and blending bin(3)The bearing that inwall is provided with(6)The company of rotation Connect, the rotary shaft(5)Positioned at blending bin(3)Internal surface loop is arranged with helical blade(7), the blending bin(3)One Side through being provided with feed hopper, the blending bin(3)Top be fixedly connected with cushion pad(8), the cushion pad(8)Top solid Second motor is connected with surely(9), second motor(9)Output shaft on be fixedly connected with gear(10), the blending bin(3) The inwall top of both sides is fixedly connected with elongated piece(11), described elongated piece(11)Inwall bottom be fixedly connected with slide rail (12), two described elongated piece(11)Between pass through slide bar(13)It is fixedly connected, and slide bar(13)Two ends extend through elongated Block(11)And extend to elongated piece(11)Inside and slide rail(12)It is slidably connected, described elongated piece(11)Inwall side fix It is connected with fixed block(14), the fixed block(14)Away from elongated piece(11)The side of inwall is fixedly connected with folding arm(15), The folding arm(15)Away from fixed block(14)One end with extend to elongated piece(11)Internal slide bar(13)It is fixedly connected, institute State slide bar(13)Middle part upper end be fixedly connected with vertical rod(16), the vertical rod(16)Top run through blending bin(3)Top And extend to blending bin(3)Outside be located at blending bin(3)The tooth bar of top(17)It is fixedly connected, the tooth bar(17)Tooth Tooth and gear(10)Teeth engagement, the vertical rod(16)Middle part bottom be fixedly connected with puddler(18), and puddler (18)Both sides be fixedly connected with stirring vane(19), the blending bin(3)Opposite side be fixedly connected with controller(20), institute State blending bin(3)Opposite side and be located at controller(20)Lower section through being provided with discharge nozzle(21), the controller(20)Point Not with the first motor(4)With the second motor(9)It is electrically connected with.
2. a kind of mixing arrangement for chemical industry equipment according to claim 1, it is characterised in that:The blending bin(3) The middle part of inwall both sides is fixedly connected with swash plate(22), and swash plate(22)With blending bin(3)Inwall between be in 40 degree of angles.
3. a kind of mixing arrangement for chemical industry equipment according to claim 1, it is characterised in that:The blending bin(3) Top offer and supply vertical rod(16)Mobile notch, and the length of notch is less than slide rail(12)Length.
4. a kind of mixing arrangement for chemical industry equipment according to claim 1, it is characterised in that:The bearing(6)Bag Include outer ring(61)And inner ring(62), and inner ring(62)It is located at outer ring(61)Inside, the outer ring(61)With inner ring(62)Between Leave in gap, and gap and be inlaid with ball(63), the inner ring(62)Inwall on be fixedly connected with Anti-slip cover(64).
5. a kind of mixing arrangement for chemical industry equipment according to claim 1, it is characterised in that:The discharge nozzle(21) On be provided with manually-operated gate(23).
CN201610900626.7A 2016-10-17 2016-10-17 Mixing device for chemical equipment Pending CN106422935A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201610900626.7A CN106422935A (en) 2016-10-17 2016-10-17 Mixing device for chemical equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201610900626.7A CN106422935A (en) 2016-10-17 2016-10-17 Mixing device for chemical equipment

Publications (1)

Publication Number Publication Date
CN106422935A true CN106422935A (en) 2017-02-22

Family

ID=58174513

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201610900626.7A Pending CN106422935A (en) 2016-10-17 2016-10-17 Mixing device for chemical equipment

Country Status (1)

Country Link
CN (1) CN106422935A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106626321A (en) * 2017-02-23 2017-05-10 吴江市强塑阀门管件厂 Plastic processing extrusion machine
CN107297177A (en) * 2017-07-31 2017-10-27 合肥恩腾电子科技有限公司 A kind of Textile Dyes mixing arrangement
CN109365509A (en) * 2018-11-01 2019-02-22 孙同娟 A kind of municipal administration gardens soil restoring device
CN112354506A (en) * 2020-12-02 2021-02-12 内蒙古农业大学 Nano-emulsion preparation device of composite sterilant

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201991926U (en) * 2011-04-29 2011-09-28 湖北金洋冶金股份有限公司 Ball bearing for blender
CN202933652U (en) * 2012-10-19 2013-05-15 中钢集团马鞍山矿山研究院有限公司 Stirrer capable of preventing material from layering
CN204564034U (en) * 2015-04-14 2015-08-19 郑州森林苑园林绿化工程有限公司 A kind of building mortar mixer of convenient movement
CN205199394U (en) * 2015-12-24 2016-05-04 张立恒 Can make thoroughly mixer of stirring of material
CN205229649U (en) * 2015-12-04 2016-05-11 武汉理工大学 Projecting apparatus projection deviation adjusting device
CN205288230U (en) * 2015-11-23 2016-06-08 朱涵 Chemical instrumentation agitating unit
CN205308219U (en) * 2015-11-25 2016-06-15 张卓睿 Chemical instrumentation shakes even device
CN206199164U (en) * 2016-10-17 2017-05-31 无锡市日升化工有限公司 A kind of mixing arrangement for chemical industry equipment

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201991926U (en) * 2011-04-29 2011-09-28 湖北金洋冶金股份有限公司 Ball bearing for blender
CN202933652U (en) * 2012-10-19 2013-05-15 中钢集团马鞍山矿山研究院有限公司 Stirrer capable of preventing material from layering
CN204564034U (en) * 2015-04-14 2015-08-19 郑州森林苑园林绿化工程有限公司 A kind of building mortar mixer of convenient movement
CN205288230U (en) * 2015-11-23 2016-06-08 朱涵 Chemical instrumentation agitating unit
CN205308219U (en) * 2015-11-25 2016-06-15 张卓睿 Chemical instrumentation shakes even device
CN205229649U (en) * 2015-12-04 2016-05-11 武汉理工大学 Projecting apparatus projection deviation adjusting device
CN205199394U (en) * 2015-12-24 2016-05-04 张立恒 Can make thoroughly mixer of stirring of material
CN206199164U (en) * 2016-10-17 2017-05-31 无锡市日升化工有限公司 A kind of mixing arrangement for chemical industry equipment

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106626321A (en) * 2017-02-23 2017-05-10 吴江市强塑阀门管件厂 Plastic processing extrusion machine
CN106626321B (en) * 2017-02-23 2018-09-21 吴江市强塑阀门管件厂 A kind of extruder of plastic processing
CN107297177A (en) * 2017-07-31 2017-10-27 合肥恩腾电子科技有限公司 A kind of Textile Dyes mixing arrangement
CN109365509A (en) * 2018-11-01 2019-02-22 孙同娟 A kind of municipal administration gardens soil restoring device
CN112354506A (en) * 2020-12-02 2021-02-12 内蒙古农业大学 Nano-emulsion preparation device of composite sterilant

Similar Documents

Publication Publication Date Title
CN106422935A (en) Mixing device for chemical equipment
CN106584675B (en) A kind of concrete mixer
CN202070307U (en) Double-planet double-power mixing dispersion machine
CN206868125U (en) It is a kind of to carry the planetary agitator for rocking function
CN106732025A (en) It is a kind of to stir the adjustable material mixing equipment for being easy to clean of scope
CN108097143A (en) A kind of chemical liquid raw material injecting type mixing arrangement
CN109464934A (en) A kind of agitating device convenient for toppling over
CN107213837A (en) A kind of medical packaging cold seal glue preparation Efficient Agitator
CN207056379U (en) A kind of new material agitating device for being easy to discharging
CN103210966A (en) Movement separation spiral multifunctional food mixing machine
CN208642509U (en) A kind of grease blender of the multi-direction rotation of staving
CN206199089U (en) A kind of two-way stirring equipment with double-stirring device
CN107875876A (en) A kind of Zongzi processing raw material blending device
CN206199164U (en) A kind of mixing arrangement for chemical industry equipment
CN207654994U (en) Manufacturing medicine extract machine
CN108554215A (en) A kind of mixing arrangement for liquid charging stock processing
CN207694621U (en) A kind of chemical liquid raw material injecting type mixing arrangement
CN206325458U (en) One kind stirring adjustable material mixed stirring device of scope
CN206868115U (en) A kind of horizontal drum mixer
CN206731131U (en) A kind of bi-motor revolving reaction kettle
CN208878353U (en) A kind of high-performance ink process units
CN208145864U (en) A kind of shear thickening liquid production composite stirring mixing arrangement
CN206690329U (en) A kind of efficient easily concrete central mix plant
CN109366775A (en) A kind of plastic processing agitation apparatus for pellets
CN213353051U (en) High-efficient mixer

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20170222

WD01 Invention patent application deemed withdrawn after publication