US2790467A

US2790467A - Vacuum filling head

Info

Publication number: US2790467A
Authority: US
Inventors: Howard A Rohdin
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-06-04
Filing date: 1948-06-04
Publication date: 1957-04-30
Anticipated expiration: 1974-04-30

Description

April 1957 H. A. ROHDIN 2,790,467

VACUUM FILLING HEAD Filed June 4, 1948 3 Sheets-Sheet 1 Howard A. Rohdm,

April 1957 H. A. ROHDIN 2,790,467

VACUUM FILLING HEAD Filed June 4, 1948 3 Sheets-Sheet 2 3m) Howard A. Bohdrv wwm April 30, 1957 H. A. ROHDIN 2,790,467

VACUUM FILLING HEAD Filed June 4, 194a s Sheets-Sheet s Howard A. Ro/Idim,

United States Patent VACUUM FILLING HEAD Howard A. Rohdin, Glen Ridge, N. J.

Application June 4, 1948, Serial No. 31,061

3 Claims. (Cl. 141-49) It is an object of this invention to provide a vacuum type filling machine so far simplified over the prior art as to be of minimum cost.

It is a further object of this invention to provide a machine of the type aforesaid which is capable of handling both sluggish and free flowing materials.

It is a further object of this invention to provide in a machine of the type aforesaid a simple adjustment to permit the machine to deliver a wide range of quantities.

It is a further object of this invention to provide a machine as aforesaid which will be easy to clean and in which a vacuum system is so arranged as to prevent any contamination of the product being handled by any product previously handled.

It is a further object of this invention to provide a machine as aforesaid in which the loss of the product being handled is minimized.

It is a further object of this invention to provide a machine as aforesaid capable of operating at a maximum speed with a minimum duration of the inactive portion of its operating cycle.

It is a further object of this invention to provide a machine as aforesaid which will have maximum accuracy in measuring a predetermined load and which will assure even consistency of the packaging between consecutive packages with a minimum of entrapped air in the package.

ice

become clogged and, therefore, must be cleaned, usually The above and other objects will be made clear from Fig. 6 is a section through still another form of head i which is particularly adapted to use in a revolving turret; and

Fig. 7 is a section of a head having a special form-of valve. 7

Certain pulverulent materials are very difficult to bring into compact condition by the ordinary mechanical jogging and squeezing methods. Typical of such materials are cocoa, the so-called instant coffees, carbon black and many chemicals, pharmaceuticals and cosmetics. It has become customary in handling materials of this type to conduct the filling operation under vacuum so as to minimize the entrapment of air between the particles. Since most of such materials are relatively light and fluify there must be provided a screen between the source of vacuum and the package, the interior of which is subjected to vacuum during the filling operation. Such screens if of fine enough mesh to be eifective rapidly several times during each filling operation. This has been accomplished in various ways but one of the most effective has been to arrange for a reversal of flow of air through the screens which effects quite thorough cleaning. The present invention is concerned among other things with effecting such a reversal of flow through the screens without, however, any reversal of flow in the ducts making up the vacuum system.

In the nature of machines of this class the precise number and type of cycles necessary to deliver a pre-determined quantity of any particular material must be determined empirically. Once this is determined, however, the maintenance of a high level of accuracy as between consecutive packages depends on minimizing the uncontrollable variables. Usually in machinesof this class, material starts to flow into the packages as soon as any appreciable vacuum is created within the package. Since initially the package is at atmospheric pressure and the vacuum in the line is in the order of 25", there will be a period of variable flow before anything approximating line vacuum is attained in the package and during this period air may become entrapped in the bottom of the package.

The present invention overcomes this by providing a gate between the supply of material and the package and making the opening of the gate responsive to the attainment within the package of substantially line vacuum. This gate is arranged to provide a minimum of space between the level of the gate and the ultimate load line of the package. This is important, particularly in the case of free flowing materials since it minimizes the otherwise variable quantity of material that may be in the air above the load line of the package when the gate is closed.

Since it is necessary to shut oil the vacuum and, therefore, discontinue filling several times during the filling of a single package in order to clear the screens the overall filling time is determined by the speed with which the vacuum can be shut oif, the screens cleaned and the vacuum resumed.

As noted above. a substantial time is required to establish pressure equilibrium and so far as the total volume involved can be reduced this time is minimized. In the present invention every step is taken as close as possible to the package itself. I

Referring now to Fig. 1, there is illustrated a filling head 10 secured to the flange 12 of a hopper 14. The inner wall 16 of the head 10 is sloped to form a continuation of the hopper. In the lower face 18 of the head is formed a gasket 20. There is also an annular groove .The valve 36 is free to rotate and is secured to a flange 38 which in turn is secured to a shaft 40. A set of openings 42 is formed in the upper disc 30 and these register with similar openings 44 in the lower disc 32. The valve 36 has a similar set of openings 46, which, as shown in Fig. 2, may be placed either in registry with the disc openings to open the valve, or out of registry to close the valve. Moreover, the extent of rotation of the valve 36 will determine the exact extent of valve opening so that various types of materials can be handled.

The shaft 40 passes through a stufiing box 48 in a casing 50. Inside the casing 50 the shaft 40 is keyed to a hollow member 52. The member 52 has a bore .54 in which are formed high pitched threads 56. The threads 56 engage mating threads 58 on a cylinder 60 which is it- 7 self secured to a shaft 62. The shaft 62 passes through 3;, the base 64 of a cage 66 which is supported onaledge GS formed in the casing 50. v

Above the base 64 the shaft-,62 is squared to fit a square boss .70 formed in the cage 66. .A pair ,of thumh-nutsjn are. threaded on the-shatt62 below thebasefiiand serves. adjustablyto limit upwards'lidingmovement of thesha tt.

nward? 62, he nce to adjust the extent of rotation;ofthegvalvei'lifif by the engagement of the .threads56 and58...

At itsupper extremity the. shaft 62 passes through a plate 74'attached to-thecage 66 and engages a-pneumatiebellowsmember.76: Belowuthe top plate 74 and surrounding the shaft 62 is a springflSQ. The spring;78 bearsat one .end;.on the plate .74and at the other endpn a .diso stlslidably mounted onrthelshaft 62. A-1- pair; of. thumb. nuts .82 are threadedon thershaft '62=.-bel w ,the disc..8 0 and serveto. adjust tension. of theaspring- 7 8.

The bellows 's secured. by: a :nut'; 84 to a'lplate ,-86; V which bears on thequpperend of t he.-cage.66.-.. A;cl, P.-. shaped cap; member .88: has threaded engagement} with ,,t he casing 50 and is securedtowtliebellows supporting-plate T sh l Q iC h ki Part -v A= cuum, tube 90- connec'ts .with thebellows76 through; the;nut "84.

The inter-relationship of the above described.- parts-wilL bemade clear by;reference.toFig.3 in whichthere is'in; dicated a va'ci um pump 92 :connected 1 through; a. valve; 94 with .the vacuumpassage, 26, of. 1 the. head- 10.; The, a valve 94 may be of any desired type and is normally-: springg closed. lit v is:provided,with. a solenoid, 94Lwhich, when.energizeiopensthe valve 9.4. The -passage 2 8 -oiu thehea'd. connects ,to the atmosphere. :throughg awalye, 96. Thevalve 96 also may beof .anydesired IyPfQendisw spring biased to a normally open position. A carn 98 is;\ provided f orperiodic .closingof the valve 96.; Thisvalve. carries a contact 100 which,,when the valve is-closed by thecam 98,,closes contacts 102 to energize the solenoid 94 andrthustoopen. the valve 94. The vacuum line 90.. which isconnected'to the bellows-76 has itsother end connected to thelin'e 28 of the head 10.

Anv actual-filling operation .will. now be described. A can or-jar to be-filled has its mouth pressed into sealed contact :Withthe gasket 0f thehead 10., and rotatiQB." of. the carn.9 8-is thenstarte d. The cam- 98' closes; the; valve 96 and the contacts 102. This energizesthegsole noid 94'--and:opens the valve 94, thus-connecting the head 10. to-thevacuum-pump92 As'pressure; drops in the head 10,. italso -drops in the line 90 and the bellows; 76;. When .;tl1e.-absolute;pressure in thes-line- 90 reaches a level predetermined by the tension of the,spring;7 8,-as=ad; juste hby thethumb. nuts 82, the bellows drawstheqshaft 62 upwardly .to the limit determined by; the, enga ement of the lowergset of thumb nuts with;thebase 64 of stile;w cage 66.. Thisrupwardmovement otthe. shaft162 -rotates;; thevalve. 36 and allows. material" tofiow. into the-canon After. aninterval determined by the speedandprloppr-x tions of the cam 98 the valve 96 is allowed to;open; and: at the same time the valve-94'isclosed .by the breaking of'the 'circuitzoi the .solenoid-;.94; T heresult is .to setup-- avpressure shochzwaveinthe head '10 which serves to clearthe'; screen 24: This-clearing.effect'isaided by the evacu-. ated spaceiinzthezcontainer which help's to draw'air di--- rectly through the screen. Obviously the breaking of the vacuum. releases .the bellows 76 and closes the valve 36. T-he' cycle may be repeated as. often. as necessary -to-fill any given container. Usually two such cycleswill suffice. ltis clear that'the vacuum step should last'much longer than the clearing step, which need only bis-momentary.

Valve-'9'6 may be connected to a-gaschamber, thereby" g.4 how a a 5 hav nsas ek t; 52 ,a 2.a 1,.

annular groove 154 covered by a screen 156. The gmo'vei 154 has a vacuum passage 1 58 and an air passage 160. The head is also provided with a material valve 162. Thus far the head 150 is identical with the head 10 of Fig. 1. The head 150, however, is provided with a narrow supplemental annular. channel 164 running between the groove 154 and the valve-162. This channel 164 has its own vacuum, connection 165'; andis not screened the connection 166 obviouslymustnotbe allowed to intersect either passages158'or 160 and therefore is shown in dotted outline-in Fig 4 The operation of the parts described in the preceding paragraph will be-undertoodfrom--a consideration of Fig. 5. Fig. 5 is entirely schematic and shows a vacuum pump 168 connected to a header 170 which leads to a normally open valve 172 which is closed by the energizn f s l ncid; 4 he. header. 17." fi q qn ests w t no ma y losede a ve 176-W ich i spsnes tbvl a sa t. noid 178. The valve 172 connects thevacuumpump 168 w ic ev cuee theroo e. 54 c v ed by the screen 156., The valve 176 connects the vacuum pump 168 to the duct 166 whichevaeuates theunscreened auxiliary channel 164. A normally closed valve 180;. is

pgn d v a 82. and ne t t e se e oove 154 tothe atmosphere through the duct l60 Thetube 90 leading-to thejbellows 76 and; its attached rod 60 connects w t rlhe uct 0.,

In starting condition the valve 172 is open and the valve- 180is closed. As pressure drops;within the head 150 the bellows 76 is collapsed by the tube 90 to-draw up the.

circuit of solenoid17 4, hence close the valve 172 which connectsgthe groove 154 with the vacuum pump 168, The, closing, oi; contacts 186 energizes the solenoid 178 which opens the valve 176 connecting the unscreened auxiliary, channel 164 with the vacuum pump 168. This draws air fromjhe; atmosphere through the valve 180, the duct 160 and ;th e screens;156 and clears the screens without, however, reversing any flqwexcept through the screens 156. As;tl1 ecam 182;c,ontinues to move, it closes the valve 180 and the contacts 184 and opens the contacts 186 This.

reverses the action just; described in that it closes, valve 176 and opens valve 172, thereby resuming the vacuum Withdrawal ofcmaterialfrom the hopper 14.

Fig. 6 shows an: exceptionally compact modification of thisinventionwhichis especially applicable. to theoperation of a number of filling heads arranged arounda'.

mill t:

Here the hopper 14 is joined to ,a head 200 which containsza. valve -202-,identical to the valve of Fig. 1. and similarlyroperated. The head 200 has an annular pas.-

sage 204 covered by a screen 206 and has the usual gasket 2086 The passage 204 is connected to a duet 210.

A ring 212 is secured by cap screws 214 to the under- SidQOf thehejad 200 and a generally similar ring 216 is secured-by'capscrews 218 to theupper side of the head 200; Anannular valve 220 surrounds the head 200 and has labyrinth grooves and ridges 222 mating with'similar grooveslandiridges-in the upper ring 216 and has a similar arrangement 224 of labyrinth grooves andv ridges mating withthe lower ring 2 12. A: gear 2261s formed integral with ztlre valve 220.

A ring 228 snrrounds -'the valve 220 "and has formed thereinfa;vaeuum channel 2,30 and an atmospheric chanf nel 252. A} sealing ring {234 surrounds the ring 228 an d contains 'a vacuum; connection 256' and an atmospher c connection- 238: The meeting surfaces of rings -228E and 234 are beveled and contain gaskets 240. A set of labyrinth grooves and ridges 242 are formed between the ring 228 and the gear 226. The sealing ring 234 is secured by cap screws 244 to the upper ring 216 through a gasket 246.

The valve 229 contains one or more passageways 248 which connect the duct 210 leading to the annular passage 204 to the vacuum chamber 230 defined by rings 228 and 234. Other passages, not shown, in the valve 220 serve to connect a duct 250 in the head 200 with the atmospheric chamber 232 also defined by the rings 228 and 234.

It is clear that by properly locating and proportioning the vacuum and atmospheric passages in the valve 220 there can be created precisely the cycle described with reference to Figs. 1 and 3. In turret operation the head 200 revolves around a fixed gear meshing with the gear 226 which has the efiect of rotating the valve 220 relative to the head 200 and the rings 228 and 234. This relative movement sequentially connects the passage 204 with vacuum and atmosphere.

It will be clear that the construction just described is equally adaptable to the form shown in Fig. 4 and the cycle described with reference to Fig. 5. Since this would involve only the addition of an unscreened annular channel in the head 200 and an auxiliary duct for occasional communication with the vacuum chamber 230.

In Fig. 7 there is illustrated a special form of valve which may be used with either of the forms of heads shown in Figs. 1 and 4. This valve has particular utility where the material being handled is gritty or abrasive. In Fig. 7 there is a head 300, attached to a hopper 302. A screened channel 304 is formed in the head 300. A valve 306 fits in the mouth of the head and is secured to a rod 308 which is attached at its other end to a diaphragm 310. The diaphragm 310 is supported by the hopper 302 by means of a spider 312, and is connected to the vacuum system by a line 314. Since the amplitude of movement is small in this case, and since the valve 306 must be lifted not only against the weight of material in the hopper but also against the vacuum in the container, the use of a diaphragm rather than a bellow is distinctly indicated.

What is claimed is:

1. In a vacuum type filling machine: a head having a screened channel and a material inlet adjacent thereto; a duct for connecting said screened channel to a source of sub-atmospheric pressure; a second and separate duct for for connecting said screened channel to a source of at least atmospheric pressure, each of said ducts having an independent valve; means for operating each of said valves; and means controlling said valve operating means to assure that when one valve is open the other is closed, and means for actuating said valve operating means one or more times prior to the completion of a filling operation.

2. In a vacuum type filling machine: a head having a screened channel and a material inlet adjacent thereto, a duct for connecting said screened channel to a source of sub-atmospheric pressure, a second and separate duct for connecting said screened channel to a source of at least atmospheric pressure, each of said ducts having an independent valve, means for operating each of said valves and means controlling said valve operating means to assure that when one valve is open the other is closed, a supplemental vacuum channel, a duct for connecting said channel to a source of vacuum, a valve in said duct, means for operating said valve and means controlling said valve operating means to assure that said valve is open only when the valve in the first vacuum duct is closed and the valve in the at least atmospheric pressure duct is open.

3. In a vacuum type filling machine for filling containers with pulverulent material: a filling head having a gasket to make sealing contact under vertically exerted presssure with the mouth of a container to be filled, said head having a vacuum channel and an inlet for pulverulent material, said vacuum channel and inlet being surrounded by said gasket; a material supply hopper mounted directly above and connected to said inlet by a passage in line with said container to be filled; a valve in said passage; means biasing said valve to closed position; vacuum means for overcoming said biasing means to open said valve, and being uninterruptedly connected to said vacuum channel.

References Cited in the file of this patent UNITED STATES PATENTS 1,981,485 Westin Nov. 20, 1934 2,168,841 Kantor Aug. 8, 1939 2,170,469 Carter Aug. 22, 1939 2,315,865 McBean Apr. 6, 1943 2,443,182 Carter June 15, 1943 2,448,733 Peebles et al. Sept. 7, 1948 FOREIGN PATENTS 470,410 Great Britain Aug. 9, 1937