CA1313445C - Apparatus and method for permanently joining plastic screw conveyor flights - Google Patents
Apparatus and method for permanently joining plastic screw conveyor flightsInfo
- Publication number
- CA1313445C CA1313445C CA000563287A CA563287A CA1313445C CA 1313445 C CA1313445 C CA 1313445C CA 000563287 A CA000563287 A CA 000563287A CA 563287 A CA563287 A CA 563287A CA 1313445 C CA1313445 C CA 1313445C
- Authority
- CA
- Canada
- Prior art keywords
- edges
- confronting
- modules
- edge
- plastic
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
- B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
- B29C66/54—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
- B29C66/543—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles joining more than two hollow-preforms to form said hollow articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14467—Joining articles or parts of a single article
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/10—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using hot gases (e.g. combustion gases) or flames coming in contact with at least one of the parts to be joined
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/40—Applying molten plastics, e.g. hot melt
- B29C65/42—Applying molten plastics, e.g. hot melt between pre-assembled parts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/70—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by moulding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/01—General aspects dealing with the joint area or with the area to be joined
- B29C66/02—Preparation of the material, in the area to be joined, prior to joining or welding
- B29C66/024—Thermal pre-treatments
- B29C66/0242—Heating, or preheating, e.g. drying
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C2045/1486—Details, accessories and auxiliary operations
- B29C2045/14868—Pretreatment of the insert, e.g. etching, cleaning
- B29C2045/14877—Pretreatment of the insert, e.g. etching, cleaning preheating or precooling the insert for non-deforming purposes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
- B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
Abstract
APPARATUS AND METHOD FOR PERMANENTLY JOINING
PLASTIC SCREW CONVEYOR FLIGHTS
ABSTRACT
Apparatus for bonding or joining confronting edges of flights of adjacent integrally molded screw conveyor modules is disclosed. The apparatus comprises means for supporting a plurality of the modules in axial alignment and with confronting edges of the module flight members in confronting relationship. Also included is a clamping means for enclosing and maintaining the confronting edges in a fixed position.
The clamping means includes at least one passage extending from outside the clamp to a position inside the clamp between the confronting edges.
A heated gas such as nitrogen is provided through the passage to the confronting edge to heat the edges substantially to the melting point of the plastic modules. Subsequent to heating the edges with the hot gas, a liquid plastic material under selected temperature and pressure is injected through the clamp passage and into the space between the confronting flight edges to fill the space between the edges and to bond the flights together.
PLASTIC SCREW CONVEYOR FLIGHTS
ABSTRACT
Apparatus for bonding or joining confronting edges of flights of adjacent integrally molded screw conveyor modules is disclosed. The apparatus comprises means for supporting a plurality of the modules in axial alignment and with confronting edges of the module flight members in confronting relationship. Also included is a clamping means for enclosing and maintaining the confronting edges in a fixed position.
The clamping means includes at least one passage extending from outside the clamp to a position inside the clamp between the confronting edges.
A heated gas such as nitrogen is provided through the passage to the confronting edge to heat the edges substantially to the melting point of the plastic modules. Subsequent to heating the edges with the hot gas, a liquid plastic material under selected temperature and pressure is injected through the clamp passage and into the space between the confronting flight edges to fill the space between the edges and to bond the flights together.
Description
APPARATUS AND METHOD FOR PERMANENll Y JOINING
PLASTIC SCREW CONVEYOR FLIGHTS
TECHNICAL FIELD
... ... . .
1 This invention relates eo apparatus and me~hods for permanently ~oinlng or bonding the flights of plastic screw conveyor modules and more particularly to such apparatus for ~oining the confronting flights of such lntegrally molded plastic screw conveyor modules in a manner suitable for meeting USDA requirements for food proce~sing. The edge~
of confrontlng flight~ of adjacent modules are enclosed and clamped in place by the app~ratus. A hot gas such as nitrogen nr air i8 then in~ec~ed between the confronting edges of the fli~hts to bring the confronting edges ~ub8tantially to the meltlng point of the plaRtic modules. A plastic material ls then in~ected under preqsure and temperature between the hea~ed confronting edge~ of the enclosed fllghts ~nd allowed to ~olidify until complete bonding take3 place.
BAC~GROUND ART
As will be appreciated by thQse ~killed ln ehe art, specialized helical shaped devices such as screw conveyors are well known for the transport of various bulk material. Such conveyors generally include a helical shaped member which rotates within a housing or trough such that rotation of the screw conveyor alo~g it~ longitudinal or central a~i~
resultY ln ~ovement of the bulk ma~erial along the length of the device~
In the past, such co~veyors were typically constructed from metal a~d 2Q each conveyor wa~ specifically de6igned for a particular purpose and of a par~icular l~ng~h. However, al~hough mo3~ prlor art conveyors were specifically designed to meet a particular application, there had been some attempts of providing a modular type conveyor of metal and/or wood. Examples of U.S. Patents which disclose such modular conveyors include U.S. Patent No. 349,233 issued to James Nelson on September 10, 1886; U.S. Patent No. 455,334 issued to H. Birkholz on July 7, 1891; UOS. Patent No 525,194 issued to J. Dyson, et al on August 20, 1894; U.S. Patent No. 546,879 issued to J. Dyson, et al on September 14, 1895; U.S. Patent No. 1,~67,573 issued to D. G. Leach on July 19, 1932; V.S. Patent No. 2,492,915 issued to A. ~. Carlson on December 27, 1949; U.S. Patent No.
3,648,826 issued to Dean P. Brooks on March 14, 1972 and U.S.
Patent No. 3,705,644 issued to Claude E. Kawchitch on December 12, 1972. However, a study of the above patents lndica-tes -that only the two Dyson, etal patents, the Nelson patent and the Kawchitch patent can be considered sectional or modular.
In addition, it is believed that apparatus is available for bonding sections of plastic pipes together in a fluid or liquid tight manner by heating the ends and pressing the melted ends together. However, the techniques and the overall concep-t as applied to bonding the edge of flights of ad~acent modular screw conveyor sections together is believed to be uniaue and different from that of bonding plastic plpe together.
1 As will be appreciated, one of the advantages of the plastic modular screw conveyor ls ease of cleaning due to the smooth and non-interrupted surfaces. Also of course, by axlally stacking any selected number of modules on the non-circular drive shaft a screw conveyor of any length can be fabrlcated. For certain appllcations, it i5 desirable the confronting edges of the flights of ad~acent modules be sealed to each other to strengthen the conveyor and to eliminate any large spaces between the flights which might trap particles of the conveyed material.
However, to pass the USDA requirements any process which fills up spaces between flights must not result in any small cavities or openings which could harbor bacteria.
Therefore the present invention seeks to provide apparatus and methods for joining or bonding the confronting edge of a flight sf one module to the confronting edge of a flight of a second module in a crevice-free manner.
I?urther the present invention seeks to provide apparatus and methods which results in a bond or joint such that the joined flight members are in reglster with each other.
Still further the present invention seeks to provide apparatus and methods which allows the flights of a multiplicity of modules to be ~oined together.
SUMMARY
These and other aspects and advantages will be obvious and wlll ln part appear hereinafter, and will be accomplished by the present lnven-tlon whieh provides apparatus and methods for bonding confronting edges of the flights of ad~acent integrally formed plastlc screw conveyor modules.
~' ~^. . ~
The apparatus for bonding the at least two confronting edges of flights of adjacent integrally molded screw conveyor modules is characterized by means for supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and with an edge of the flight member of one of the plurality in confronting relationship with and edge of the flight member of another one of the plurality, means for enclosing the confronting edges and maintaining the edges in a fixed position, the enclosing means including at least one passage from outside the enclosing means to the confronting edges, means for providing a gas such as nitrogen having an elevated temperature through a passage to the confronting edges to heat the edges substantially to the melting temperature of the plastic modules and means for injecting a plastic materla]. under temperature and pressure through a passage of the enclosing means between the heated and confronting edges o:E the modules to bond or join an edge oE one module of the plurality to the confronting edge of an adjacant module of the plurality.
Another aspect of the invention provides a method for bonding at least two confronting edges of the flight of adjacent integrally molded screw conveyor modules characterized by the steps of supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and wi~h an edge of the flight members of one of the plurality in confronting relationship with an edge of the flight member of an adjacent one of the plurality, enclosing the confronting edges of the adjacent modules in a fluid tight manner and maintaining the edges in a fixed position, providing a gas such as nitrogen at an elevated temperature to the confronting edges to heat the confronting edges to substantially the melting temperature of the plastic modules, injecting a plastic material under temperature and pressure between the heated and confronting enclosed edges of the modules so as to bond or join an edge of one module of the plurality to the confronting edge of an adjacent module of the plurality and cooling the injected plastic material such that the material changes to a sol.id thereby providing a bond between the confronting flight members.
A
~ 4-_ EF DESCRIPTION OF THE DRAWINGS
The above features of the present invention will be more clearly understood from consideration of the following description in connection with the accompanying drawings in which:
Fig. 1 is a plan view of a plurality of screw conveyor modules showing one set of confronting flight member edges filled and bonded by the methods and apparatus of this invention and two other sets of confronting edges prior to filling and bonding.
Fig. 2 is a perspective view of one embodiment of the apparatus of the present invention.
Figs. 3A and ~B show a plan view and an end view respectively of the apparatus of Fig. 2, ...~
3 .f ~Lr ~ ~
1 Flg. 4, 1B an enlarged view of the clamping apparatu~ of Flg. 2.
Fig. 5, is a plan view of a portion of the apparatu~ of Flg. 1 3howing means for providing hot gas to the full length of the edges to be bonded.
Referr~ng now to Figo 1~ there is shown a plan view of a plurallty 10 of plastic screw conveyor modules 12, 14, 16 and 18. The modules are axlally allgned as shown, and although ehe hub or axial members 20, 22, 24 and 26 of ad~acent modules are ~oined or bonded and in contact with each other, it is clearly seen that ~ap~ or spaces represented by double arrows 28 and 30 exist between ~he confron~ing ed~es 32 and 34, and 36 and 38 r2spectlvely of flight members 40, 42 and 44. On the other hand, the original space indicated by dotted lines . 46 and 48 between confronting edges of flight member~ 44 and 509 illustrate how the space between confro~ting edge~ of flight members i9 filled thereby ~olning and bo~ding the edges according to the methods and apparatus of ~his invention. The USDA requirements can normally be achieved by ~olnlng the ends of the axial members or hub~ together in a fluid tight m~n~er such that there are no tiny crevices or openlngs to collect fluids and harbor the growth of bacterla. For example a~ iB 6hown in Fig. 1, modules 12 and 14 are seen to be clearly bondet together as in~lcated by seam 52. In a ~milar manner, module3 14 and 16 are bonded by Beam 54 as are modules 16 and 18 bonded by ~eam 56. A~ mencioned, typically the bonding of the hubs or axlal member~ of the modules l~ a saeisfactory manner i~ all that i8 necessary ~o achieve USDA approval. ~hen only the ~3 ~
1 bonding of the a~ial members of the module~ i~ achieved ln thls w~y, sufficient gaps or spaces remain between the confronting edges of flight members such tha~ the gaps or ~paoe~ can be readily cleaned and i~spected. For example, the spaces and gaps indicated by double arrows 28 and 30 illustrate ~uch clearances. ~owever, it i8 often desirable to have a flight member whlch has no discontinuitie~ in ~he entire length of the flight member from one end to the other. To accomplish this, the edges of tha confrontlng flight members musi: be ~oined or bonded together, and to meet USDA specifications the bond must be completely free of tlny openlngs or crevices which could colleet bacteria and fluids. Therefore, the resulting ~oint or bond for~ed by the apparatus snd ~ethod of the present lnvention mu~t be a high quality, smooth and fluid-tight bond.
Referring now to Figq. 2, 3A and 3B, there is shown a perspective viewr a plan view snd an end view of the apparatus of the pre~ent invention which show~ a plurality of modules wherein the confronting edges of flight members are being bonded and jolned according to the teachings of this inventlon. A~ 6hown in Figs. 2 and 3A, there i8 a multiplicity of modules of the screw conveyor which have the flight members ~oined to provide 8 continuous flight member the entlre length of ~he ~odules. As shown, the modules indlcated generally a6 58 are ~upported by a three-~ection support stand or means 60, 62 and 64. The center or prlmary support unit 60 ~upports the modules presently being bonded, whereas ~he auxlliary support stands 62 and 64 simply provide support for those modules already having their flights ~oined or those modules whlch will have their flights Joined. As can be seen, support stands 62 and 64 may readily have their heighe ad~uQted by mean~
.
1 of adJu~tlng ~crews 66 and 68 respectively. In general, the support stands 62 and 64 include a table portion 70 and 72 each of which may hold a pa~r of parallel support rails 74 and 76 25 shown in Fig. 3A (not shown ln Fig. 2). These support rails receive and support the flight S members of the ~oined screw conveyor. In a slmilar manner, the main support means 60 also includes a pair of support rail~ 78 and 80~ Also as can readily be seen, table 82 which carry support rails ?8 and 80 may readlly be ad~ust~d by means of a crank 84 and rack and gear &rrangement indlcated by reference number 86. As can be seen, the rail~ 78 and 80 support the plurality of modular screw conveyors 58 such that centerline 88 of the pLurallty of 3crew conveyor 58 is aligned with the heating-head 90 and in~ection head 92 to be di~cussed in detail hereinafter.
Fig. 4, shows flight members 94 and 96 of two axlally ~olned modules as indlcated by bead 95. Al~hough blocked from view in the Pig.
4, there will be a gap between the confronting edges of fllght members 94 and 96 such as the gaps indicated in Flg. 1 by double arrow3 28 and 30. Also as ~hown there is an encloslng clamp means 98 ~omprised of two sectlons 100 and 102 which fit on each side of the two confronting flight members. Enclosing clamp 98 ~ill have a pair of surfaces which will conform to the two parsllel helical surfaces of the flight member3.
For ease of illustration, the enclosing clamp me~ber 98 is shown being held tightly in position by means of a manual C-clamp 104. ~owever, lt wlll be appreciated that in lieu of 2 simple hand manipulated C-clamp 104~ au~omatic clamping means could be used to hold the ~wo portions 100 and 102 of the clamp in position. As can be seen clamping means 98 extends from the hub 106 of the modules to be ~olned out beyond the edge ~3~3'~
1 108~ Also as will be appreclated, the edges of the clamp flt ~nu~lyagainst the plastic flight members to provide substantially a fl~id-tight enclosure. At the top portion 110 of enclosing clamp 98, there is shown an opening 112. As wlll be appreciated and discussed S hereinafter, openl~g 112 ~llows ho~ gases to be provided to thP
confronting edges of the flight members to be Joined and also allows the in;ection of melted plastic under high temperat~res and pressure8 .
Referring again to Figs. 2,3A and 3B, it wlll be appreciated that in the embodiment as ~ho~n those modules to the lef~ of heaeing and in~ection-heads 90 and 92 and which are supported by support stand 62 have already had their flights filled and bonded according to the teaching of this invention. In operation, a pair of modules such as modules 114 and 116 are moved to a position directly below heating-heRd 90. And as shown in Fig. 5, heating-head 90 includes a source of ga~
such as nitrogen heated to elevated temperatures on the order of 550F
and provided through tube 118. Heating-head 90 also includes a substantially tubular member 120 which has a cro~s-section 3ubstantially equal and conformin~ to the cross-section of the space between the two confronting edges of the flight members being ~oined. In addition, tubular member 120 includes a plurality of apertures or hole-q such as aperture 122, 124 and 126 such that hot air forced into tube 120 will leave through the apertures. Thus, when the ln~ection tube 120 i3 inserted completely into the opening 112 of enclo~ure cla~p 98, the e~be will be between the two confronting edges of the flight ~embers to be joined and thus when the hot air i~ forced into the tube the ho~ air will escape the openings 122, 124 and 126 thereby heatlng ehe ad~acen~
~3~
plastic confronting edges of the modules to a temperature substantlally equal to or slightly less than the temperature of the melting polnt of the plastic materlal. As examples only, the confronting edges of the modules to be bonded would be heated to about 550F, 500F and 500F for polypropylene, polyethylene and polyurethane respectively. The in~ection tube 120 is then removed and the pair of modules 114 and 116 to be ~oined are moved directly below the lnjection-head 92. In~ection-head 92 ls lowered such that nozzle 128 is ln contact with the opening 112. An appropriate plastic which will be compatible to the pla~tic of 0 the modules 114 and 116 is then inJection under high temperature~ and pressures as a liquid form into the space between the two confronting edges of the flight members so as to completely fill the ~pace. Agaln as example~ only, the inJection pressure and temperature for bonding polypropylene, polyethylene and polyure~hane are 60 PSI at 450F for polypropylene, 60 PSI at 375F for polyethylene, and 60 PSI at 400F for polyurethane.
In the embodiment shown, only a single passage 112 i~ shown whlch runs from out~ide enclosing clamp 98 to the space inaide clamp 98 between confronting edges of flight members 94 and 96. However, it wlll 7 be appreclated ~hat separate passages may be provided for providing the hot gas and the hot plastic. Also, although the u~e of tubular member 120 i~ believed to provide more even heatlng of the edges to be ~oined or bonded, it is possible to provide the hot gas without the tubular member being lnserted.
Once the plastlc has been injected, the noz~le 128 is then raised from the openlng 112 and the modules 114 and 116 moved out of the way to _g_ -` ~3~3~
1 cool and make ready for the filling and bondlng of the next ~et of flight members. The clamp i9 then removed leaving the flight member3 filled and bonded with a smooth ~oine whlch meets USDA speciflcations and requirements.
Thus altnough there has been de~cribed to this point particular embodiments of the apparatus and methods for filling and bonding con~
fronting edges of the flight membDrs of the axially allgned and ad~acent ~crew conveyor modules, it is not intended tha~ such reference be construed as limitations upon the scope of the invention except in~ofar as to set forth in the following claims.
PLASTIC SCREW CONVEYOR FLIGHTS
TECHNICAL FIELD
... ... . .
1 This invention relates eo apparatus and me~hods for permanently ~oinlng or bonding the flights of plastic screw conveyor modules and more particularly to such apparatus for ~oining the confronting flights of such lntegrally molded plastic screw conveyor modules in a manner suitable for meeting USDA requirements for food proce~sing. The edge~
of confrontlng flight~ of adjacent modules are enclosed and clamped in place by the app~ratus. A hot gas such as nitrogen nr air i8 then in~ec~ed between the confronting edges of the fli~hts to bring the confronting edges ~ub8tantially to the meltlng point of the plaRtic modules. A plastic material ls then in~ected under preqsure and temperature between the hea~ed confronting edge~ of the enclosed fllghts ~nd allowed to ~olidify until complete bonding take3 place.
BAC~GROUND ART
As will be appreciated by thQse ~killed ln ehe art, specialized helical shaped devices such as screw conveyors are well known for the transport of various bulk material. Such conveyors generally include a helical shaped member which rotates within a housing or trough such that rotation of the screw conveyor alo~g it~ longitudinal or central a~i~
resultY ln ~ovement of the bulk ma~erial along the length of the device~
In the past, such co~veyors were typically constructed from metal a~d 2Q each conveyor wa~ specifically de6igned for a particular purpose and of a par~icular l~ng~h. However, al~hough mo3~ prlor art conveyors were specifically designed to meet a particular application, there had been some attempts of providing a modular type conveyor of metal and/or wood. Examples of U.S. Patents which disclose such modular conveyors include U.S. Patent No. 349,233 issued to James Nelson on September 10, 1886; U.S. Patent No. 455,334 issued to H. Birkholz on July 7, 1891; UOS. Patent No 525,194 issued to J. Dyson, et al on August 20, 1894; U.S. Patent No. 546,879 issued to J. Dyson, et al on September 14, 1895; U.S. Patent No. 1,~67,573 issued to D. G. Leach on July 19, 1932; V.S. Patent No. 2,492,915 issued to A. ~. Carlson on December 27, 1949; U.S. Patent No.
3,648,826 issued to Dean P. Brooks on March 14, 1972 and U.S.
Patent No. 3,705,644 issued to Claude E. Kawchitch on December 12, 1972. However, a study of the above patents lndica-tes -that only the two Dyson, etal patents, the Nelson patent and the Kawchitch patent can be considered sectional or modular.
In addition, it is believed that apparatus is available for bonding sections of plastic pipes together in a fluid or liquid tight manner by heating the ends and pressing the melted ends together. However, the techniques and the overall concep-t as applied to bonding the edge of flights of ad~acent modular screw conveyor sections together is believed to be uniaue and different from that of bonding plastic plpe together.
1 As will be appreciated, one of the advantages of the plastic modular screw conveyor ls ease of cleaning due to the smooth and non-interrupted surfaces. Also of course, by axlally stacking any selected number of modules on the non-circular drive shaft a screw conveyor of any length can be fabrlcated. For certain appllcations, it i5 desirable the confronting edges of the flights of ad~acent modules be sealed to each other to strengthen the conveyor and to eliminate any large spaces between the flights which might trap particles of the conveyed material.
However, to pass the USDA requirements any process which fills up spaces between flights must not result in any small cavities or openings which could harbor bacteria.
Therefore the present invention seeks to provide apparatus and methods for joining or bonding the confronting edge of a flight sf one module to the confronting edge of a flight of a second module in a crevice-free manner.
I?urther the present invention seeks to provide apparatus and methods which results in a bond or joint such that the joined flight members are in reglster with each other.
Still further the present invention seeks to provide apparatus and methods which allows the flights of a multiplicity of modules to be ~oined together.
SUMMARY
These and other aspects and advantages will be obvious and wlll ln part appear hereinafter, and will be accomplished by the present lnven-tlon whieh provides apparatus and methods for bonding confronting edges of the flights of ad~acent integrally formed plastlc screw conveyor modules.
~' ~^. . ~
The apparatus for bonding the at least two confronting edges of flights of adjacent integrally molded screw conveyor modules is characterized by means for supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and with an edge of the flight member of one of the plurality in confronting relationship with and edge of the flight member of another one of the plurality, means for enclosing the confronting edges and maintaining the edges in a fixed position, the enclosing means including at least one passage from outside the enclosing means to the confronting edges, means for providing a gas such as nitrogen having an elevated temperature through a passage to the confronting edges to heat the edges substantially to the melting temperature of the plastic modules and means for injecting a plastic materla]. under temperature and pressure through a passage of the enclosing means between the heated and confronting edges o:E the modules to bond or join an edge oE one module of the plurality to the confronting edge of an adjacant module of the plurality.
Another aspect of the invention provides a method for bonding at least two confronting edges of the flight of adjacent integrally molded screw conveyor modules characterized by the steps of supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and wi~h an edge of the flight members of one of the plurality in confronting relationship with an edge of the flight member of an adjacent one of the plurality, enclosing the confronting edges of the adjacent modules in a fluid tight manner and maintaining the edges in a fixed position, providing a gas such as nitrogen at an elevated temperature to the confronting edges to heat the confronting edges to substantially the melting temperature of the plastic modules, injecting a plastic material under temperature and pressure between the heated and confronting enclosed edges of the modules so as to bond or join an edge of one module of the plurality to the confronting edge of an adjacent module of the plurality and cooling the injected plastic material such that the material changes to a sol.id thereby providing a bond between the confronting flight members.
A
~ 4-_ EF DESCRIPTION OF THE DRAWINGS
The above features of the present invention will be more clearly understood from consideration of the following description in connection with the accompanying drawings in which:
Fig. 1 is a plan view of a plurality of screw conveyor modules showing one set of confronting flight member edges filled and bonded by the methods and apparatus of this invention and two other sets of confronting edges prior to filling and bonding.
Fig. 2 is a perspective view of one embodiment of the apparatus of the present invention.
Figs. 3A and ~B show a plan view and an end view respectively of the apparatus of Fig. 2, ...~
3 .f ~Lr ~ ~
1 Flg. 4, 1B an enlarged view of the clamping apparatu~ of Flg. 2.
Fig. 5, is a plan view of a portion of the apparatu~ of Flg. 1 3howing means for providing hot gas to the full length of the edges to be bonded.
Referr~ng now to Figo 1~ there is shown a plan view of a plurallty 10 of plastic screw conveyor modules 12, 14, 16 and 18. The modules are axlally allgned as shown, and although ehe hub or axial members 20, 22, 24 and 26 of ad~acent modules are ~oined or bonded and in contact with each other, it is clearly seen that ~ap~ or spaces represented by double arrows 28 and 30 exist between ~he confron~ing ed~es 32 and 34, and 36 and 38 r2spectlvely of flight members 40, 42 and 44. On the other hand, the original space indicated by dotted lines . 46 and 48 between confronting edges of flight member~ 44 and 509 illustrate how the space between confro~ting edge~ of flight members i9 filled thereby ~olning and bo~ding the edges according to the methods and apparatus of ~his invention. The USDA requirements can normally be achieved by ~olnlng the ends of the axial members or hub~ together in a fluid tight m~n~er such that there are no tiny crevices or openlngs to collect fluids and harbor the growth of bacterla. For example a~ iB 6hown in Fig. 1, modules 12 and 14 are seen to be clearly bondet together as in~lcated by seam 52. In a ~milar manner, module3 14 and 16 are bonded by Beam 54 as are modules 16 and 18 bonded by ~eam 56. A~ mencioned, typically the bonding of the hubs or axlal member~ of the modules l~ a saeisfactory manner i~ all that i8 necessary ~o achieve USDA approval. ~hen only the ~3 ~
1 bonding of the a~ial members of the module~ i~ achieved ln thls w~y, sufficient gaps or spaces remain between the confronting edges of flight members such tha~ the gaps or ~paoe~ can be readily cleaned and i~spected. For example, the spaces and gaps indicated by double arrows 28 and 30 illustrate ~uch clearances. ~owever, it i8 often desirable to have a flight member whlch has no discontinuitie~ in ~he entire length of the flight member from one end to the other. To accomplish this, the edges of tha confrontlng flight members musi: be ~oined or bonded together, and to meet USDA specifications the bond must be completely free of tlny openlngs or crevices which could colleet bacteria and fluids. Therefore, the resulting ~oint or bond for~ed by the apparatus snd ~ethod of the present lnvention mu~t be a high quality, smooth and fluid-tight bond.
Referring now to Figq. 2, 3A and 3B, there is shown a perspective viewr a plan view snd an end view of the apparatus of the pre~ent invention which show~ a plurality of modules wherein the confronting edges of flight members are being bonded and jolned according to the teachings of this inventlon. A~ 6hown in Figs. 2 and 3A, there i8 a multiplicity of modules of the screw conveyor which have the flight members ~oined to provide 8 continuous flight member the entlre length of ~he ~odules. As shown, the modules indlcated generally a6 58 are ~upported by a three-~ection support stand or means 60, 62 and 64. The center or prlmary support unit 60 ~upports the modules presently being bonded, whereas ~he auxlliary support stands 62 and 64 simply provide support for those modules already having their flights ~oined or those modules whlch will have their flights Joined. As can be seen, support stands 62 and 64 may readily have their heighe ad~uQted by mean~
.
1 of adJu~tlng ~crews 66 and 68 respectively. In general, the support stands 62 and 64 include a table portion 70 and 72 each of which may hold a pa~r of parallel support rails 74 and 76 25 shown in Fig. 3A (not shown ln Fig. 2). These support rails receive and support the flight S members of the ~oined screw conveyor. In a slmilar manner, the main support means 60 also includes a pair of support rail~ 78 and 80~ Also as can readily be seen, table 82 which carry support rails ?8 and 80 may readlly be ad~ust~d by means of a crank 84 and rack and gear &rrangement indlcated by reference number 86. As can be seen, the rail~ 78 and 80 support the plurality of modular screw conveyors 58 such that centerline 88 of the pLurallty of 3crew conveyor 58 is aligned with the heating-head 90 and in~ection head 92 to be di~cussed in detail hereinafter.
Fig. 4, shows flight members 94 and 96 of two axlally ~olned modules as indlcated by bead 95. Al~hough blocked from view in the Pig.
4, there will be a gap between the confronting edges of fllght members 94 and 96 such as the gaps indicated in Flg. 1 by double arrow3 28 and 30. Also as ~hown there is an encloslng clamp means 98 ~omprised of two sectlons 100 and 102 which fit on each side of the two confronting flight members. Enclosing clamp 98 ~ill have a pair of surfaces which will conform to the two parsllel helical surfaces of the flight member3.
For ease of illustration, the enclosing clamp me~ber 98 is shown being held tightly in position by means of a manual C-clamp 104. ~owever, lt wlll be appreciated that in lieu of 2 simple hand manipulated C-clamp 104~ au~omatic clamping means could be used to hold the ~wo portions 100 and 102 of the clamp in position. As can be seen clamping means 98 extends from the hub 106 of the modules to be ~olned out beyond the edge ~3~3'~
1 108~ Also as will be appreclated, the edges of the clamp flt ~nu~lyagainst the plastic flight members to provide substantially a fl~id-tight enclosure. At the top portion 110 of enclosing clamp 98, there is shown an opening 112. As wlll be appreciated and discussed S hereinafter, openl~g 112 ~llows ho~ gases to be provided to thP
confronting edges of the flight members to be Joined and also allows the in;ection of melted plastic under high temperat~res and pressure8 .
Referring again to Figs. 2,3A and 3B, it wlll be appreciated that in the embodiment as ~ho~n those modules to the lef~ of heaeing and in~ection-heads 90 and 92 and which are supported by support stand 62 have already had their flights filled and bonded according to the teaching of this invention. In operation, a pair of modules such as modules 114 and 116 are moved to a position directly below heating-heRd 90. And as shown in Fig. 5, heating-head 90 includes a source of ga~
such as nitrogen heated to elevated temperatures on the order of 550F
and provided through tube 118. Heating-head 90 also includes a substantially tubular member 120 which has a cro~s-section 3ubstantially equal and conformin~ to the cross-section of the space between the two confronting edges of the flight members being ~oined. In addition, tubular member 120 includes a plurality of apertures or hole-q such as aperture 122, 124 and 126 such that hot air forced into tube 120 will leave through the apertures. Thus, when the ln~ection tube 120 i3 inserted completely into the opening 112 of enclo~ure cla~p 98, the e~be will be between the two confronting edges of the flight ~embers to be joined and thus when the hot air i~ forced into the tube the ho~ air will escape the openings 122, 124 and 126 thereby heatlng ehe ad~acen~
~3~
plastic confronting edges of the modules to a temperature substantlally equal to or slightly less than the temperature of the melting polnt of the plastic materlal. As examples only, the confronting edges of the modules to be bonded would be heated to about 550F, 500F and 500F for polypropylene, polyethylene and polyurethane respectively. The in~ection tube 120 is then removed and the pair of modules 114 and 116 to be ~oined are moved directly below the lnjection-head 92. In~ection-head 92 ls lowered such that nozzle 128 is ln contact with the opening 112. An appropriate plastic which will be compatible to the pla~tic of 0 the modules 114 and 116 is then inJection under high temperature~ and pressures as a liquid form into the space between the two confronting edges of the flight members so as to completely fill the ~pace. Agaln as example~ only, the inJection pressure and temperature for bonding polypropylene, polyethylene and polyure~hane are 60 PSI at 450F for polypropylene, 60 PSI at 375F for polyethylene, and 60 PSI at 400F for polyurethane.
In the embodiment shown, only a single passage 112 i~ shown whlch runs from out~ide enclosing clamp 98 to the space inaide clamp 98 between confronting edges of flight members 94 and 96. However, it wlll 7 be appreclated ~hat separate passages may be provided for providing the hot gas and the hot plastic. Also, although the u~e of tubular member 120 i~ believed to provide more even heatlng of the edges to be ~oined or bonded, it is possible to provide the hot gas without the tubular member being lnserted.
Once the plastlc has been injected, the noz~le 128 is then raised from the openlng 112 and the modules 114 and 116 moved out of the way to _g_ -` ~3~3~
1 cool and make ready for the filling and bondlng of the next ~et of flight members. The clamp i9 then removed leaving the flight member3 filled and bonded with a smooth ~oine whlch meets USDA speciflcations and requirements.
Thus altnough there has been de~cribed to this point particular embodiments of the apparatus and methods for filling and bonding con~
fronting edges of the flight membDrs of the axially allgned and ad~acent ~crew conveyor modules, it is not intended tha~ such reference be construed as limitations upon the scope of the invention except in~ofar as to set forth in the following claims.
Claims (5)
1. Apparatus for bonding at least two confronting edges of flights of adjacent integrally molded screw conveyor modules characterized by:
means for supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and with an edge of the flight member of one of said plurality in confronting relationship with and edge of the flight member of another one of said plurality;
means for enclosing said confronting edges and maintaining said edges in a fixed position, said enclosing means including at least one passage from outside said enclosing means to said confronting edges;
means for providing a fluid having an elevated temperature through a passage to said confronting edges to heat said edges substantially to the melting temperature of said plastic modules; and means for injecting a plastic material under temperature and pressure through a passage of said enclosing means between said heated and confronting edges of said modules to bond or join an edge of one module of said plurality to the confronting edge of an adjacent module of said plurality.
means for supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and with an edge of the flight member of one of said plurality in confronting relationship with and edge of the flight member of another one of said plurality;
means for enclosing said confronting edges and maintaining said edges in a fixed position, said enclosing means including at least one passage from outside said enclosing means to said confronting edges;
means for providing a fluid having an elevated temperature through a passage to said confronting edges to heat said edges substantially to the melting temperature of said plastic modules; and means for injecting a plastic material under temperature and pressure through a passage of said enclosing means between said heated and confronting edges of said modules to bond or join an edge of one module of said plurality to the confronting edge of an adjacent module of said plurality.
2. The apparatus of claim 1 wherein said means for providing a fluid are further characterized by a tube connected to a source of said fluid and having a cross-section which substantially conforms to the cross-section of the space between said confronting edges, and which has a plurality of perforations along its length, said tube being inserted through a passage of said enclosing means to a location between said confronting edges such that hot fluid provided to said tube escape through said perforations to heat said edges.
3. The apparatus of claim 1 wherein said means for providing a fluid is characterized by means for providing nitrogen gas.
4. The apparatus of claim 1 wherein said means for injecting is a means for injecting a plastic suitable for bonding to plastic modules made from a material selected from the group of polypropylene, polyethylene and polyurethane.
5. A method for bonding at least two confronting edges of the flight of adjacent integrally molded screw conveyor modules characterized by the steps of:
supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and with an edge of the flight members of one of said plurality in confronting relationship with an edge of the flight member of an adjacent one of said plurality;
enclosing said confronting edges of said adjacent modules in a fluid tight manner, and maintaining said edges in a fixed position;
providing a gas at an elevated temperature to said confronting edges to heat said confronting edges to substantially the melting temperature of said plastic modules;
injecting a plastic material under temperature and pressure between said heated and confronting enclosed edges of said modules so as to bond or join an edge of one module of said plurality to the confronting edge of an adjacent module of said plurality; and cooling said injected plastic material such that said material changes to a solid thereby providing a bond between said confronting flight members.
supporting a plurality of integrally molded plastic screw conveyor modules in axial alignment and with an edge of the flight members of one of said plurality in confronting relationship with an edge of the flight member of an adjacent one of said plurality;
enclosing said confronting edges of said adjacent modules in a fluid tight manner, and maintaining said edges in a fixed position;
providing a gas at an elevated temperature to said confronting edges to heat said confronting edges to substantially the melting temperature of said plastic modules;
injecting a plastic material under temperature and pressure between said heated and confronting enclosed edges of said modules so as to bond or join an edge of one module of said plurality to the confronting edge of an adjacent module of said plurality; and cooling said injected plastic material such that said material changes to a solid thereby providing a bond between said confronting flight members.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/039,697 US4746384A (en) | 1987-04-20 | 1987-04-20 | Apparatus and method for permanently joining plastic screw conveyor flights |
| US039,697 | 1987-04-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1313445C true CA1313445C (en) | 1993-02-09 |
Family
ID=21906896
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000563287A Expired - Fee Related CA1313445C (en) | 1987-04-20 | 1988-04-05 | Apparatus and method for permanently joining plastic screw conveyor flights |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4746384A (en) |
| EP (1) | EP0288821B1 (en) |
| CA (1) | CA1313445C (en) |
| DE (1) | DE3851567T2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5099985A (en) * | 1983-09-29 | 1992-03-31 | The Laitram Corporation | Unitary screw conveyor apparatus |
| US4913280A (en) * | 1988-12-20 | 1990-04-03 | Du Pont Canada Inc. | Auger for particulate materials |
| US5899319A (en) * | 1996-10-09 | 1999-05-04 | Farmers Rice Milling Company, Inc. | Coupling and process for screw conveyors |
| ATA208197A (en) | 1997-12-09 | 2004-02-15 | Klug Kanal Leitungs Und Umwelt | METHOD FOR BONDING ARTICLES FROM PLASTIC BY MEANS OF A MELT ADHESIVE |
| SE0102452L (en) * | 2001-07-05 | 2003-01-06 | Core Link Ab | Method and device for jointing |
| JP4281332B2 (en) * | 2001-12-18 | 2009-06-17 | 株式会社デンソー | Resin product joining method |
| JP4023465B2 (en) * | 2004-03-25 | 2007-12-19 | 株式会社デンソー | Heating medium feeding method and apparatus during secondary molding of resin molded product |
| USD943650S1 (en) * | 2021-02-05 | 2022-02-15 | Xinwei Li | Auger drill bit |
| USD942517S1 (en) * | 2021-02-07 | 2022-02-01 | Jun Li | Auger drill bit |
| USD944301S1 (en) * | 2021-02-07 | 2022-02-22 | Jun Li | Auger drill bit |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2815852A (en) * | 1953-08-17 | 1957-12-10 | Allis Chalmers Mfg Co | Auger conveyer extension |
| GB1128878A (en) * | 1967-06-02 | 1968-10-02 | Standard Telephones Cables Ltd | Moulded cable sheath joint |
| US3705644A (en) * | 1970-01-23 | 1972-12-12 | Claude Edward Kawchitch | Conveyor screw element |
| US3664444A (en) * | 1970-05-11 | 1972-05-23 | Mobile Drilling Co Inc | Air drilling method using controlled split stream |
| US3839126A (en) * | 1972-07-03 | 1974-10-01 | Dow Chemical Co | Plastic welding apparatus |
| JPS57140119A (en) * | 1981-02-26 | 1982-08-30 | Aisin Seiki Co Ltd | Nozzle of hot-air welder for bonding different resin members |
| FR2519579A1 (en) * | 1982-01-14 | 1983-07-18 | Commissariat Energie Atomique | Heat exchanger plates made by assembling polymer modules - where module ends are placed in mould filled with polymer to join modules together |
| IL70561A0 (en) * | 1982-12-30 | 1984-03-30 | Orreus Ltd | Treatment of cloth materials |
| US4691818A (en) * | 1986-01-27 | 1987-09-08 | The Laitram Corp. | Concealed drive coupling for use with modular screw conveyor |
-
1987
- 1987-04-20 US US07/039,697 patent/US4746384A/en not_active Expired - Lifetime
-
1988
- 1988-04-05 CA CA000563287A patent/CA1313445C/en not_active Expired - Fee Related
- 1988-04-13 DE DE3851567T patent/DE3851567T2/en not_active Expired - Fee Related
- 1988-04-13 EP EP88105862A patent/EP0288821B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE3851567D1 (en) | 1994-10-27 |
| EP0288821A3 (en) | 1991-07-31 |
| US4746384A (en) | 1988-05-24 |
| EP0288821A2 (en) | 1988-11-02 |
| EP0288821B1 (en) | 1994-09-21 |
| DE3851567T2 (en) | 1995-04-27 |
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