US2774094A - Liquid applicator for packaging machines and the like - Google Patents

Description

Dec. 18, 1956 R. RUTHERFORD 2,774,094

LIQUID APPLICATOR FOR PACKAGING MACHINES AND THE LIKE @WW @wk x e5 Filed May 16, 1951 INVENTOR. ROBERT RUTHERFO RD ATTORNIEYS United States Patent" LIQUID APPLICATOR FOR PACKAGING MACHINES AND THE LIKE Robert Rutherford, Springfield, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Application May 16, 1951, Serial No.-226,566

1 Claim. (Cl. -127) This invention relates in general to an apparatus'for applying a liquid coating to a surface, and more specifically to a device for applying a controlled quantity of liqiud as a coating on a surface wherein there is relative movement between the apparatus and surface.

The application of liquids as finishes, lubricators, seals and like purposes has introduced applicators of varied designs. Generally, the only requirement to be met is that of smearing a surface with a liquid in insuflicient quantity to drip or run. Where moving surfaces are concerned, excess quantities are usually removed by a wiper coupled with the applicator. This combination of devices interferes with production operations and increases the cost of the treated product. In continuously operating production lines, such are are represented by extruders where the final step is a completed package, it is necessary to rigidly control the application of the liquid without intervening apparatus. It is an object of the invention to provide an eflicient device for directly applying a regulated evenly distributed coating of liquid to a surface wherein there is relative movement between the apparatus and the surface.

The invention consists of a reservoir for holding a quantity of the liquid to be applied on the moving surface. Sealed in the lower part of the reservoir, a porous body is subjected directly to the liquid and transmits it throughout the entire mass equally, and at controlled flow. The liquid quantity passing through the porous member is received by an absorbent pad which further distributes it, but does not alter the flow control of the porous body. The absorbent pad fills the remaining volume of the reservoir housing and extends downwardly to thrust against a replaceable fabric cover which is the surface for contacting the movingbody.

In order that a better understanding of the invention may be had, reference is made to the following detailed description and the accompanying drawings in which:

Figure l is a plan view of the device on the applicator side.

Figure 2 is a side elevational View of the applicator.

Figure 3 is an end elevational view of the applicator.

Figure 4 is a sectional view along lines 44 of Figure 2.

The conditions for which the disclosed apparatus is designed are generally associated with production line packaging. The operation is continuous and the coating of the liquid supplied by the device is required to be positive yet controlled in quantity. These requirements are found in moistem'ng adhesive bindings for sealing purposes, in coating contact surfaces of packaged items which tend to stick together in storage or shipment such as cakes of wax, and for other similar conditions.

According to the present invention, advantage is taken of the control and distribution .of coating material maintained in form of flowing liquid to pass easily and accurately through a porous member for even flow and distribution. Abutting the porous member, a body of ice absorbent material receives the liquid for application to the receiving surface through a replaceable fabric cover.- The porous and absorbent members afford a liquid con trol which is .novel and particularly useful under the noted application. Valves and other controls which in-' termittently flood and dam the movement of the liquid to the absorbent member are eliminated.

Referring now to the drawings, in which the same elements are indicated by the same numeral, the covered reservoir housing 10 is adapted to receive and store a liquid volume 12 in the upper section. The liquid is admitted to the reservoir through the tapped aperture 13 in which a pipe connection will fit. A supply of liquid is furnished under a selected pressure head from a source not shown as the supply method and apparatus do not form a part of this application. It is only necessary that the pressure head be known and constant as will be fully understood later in the specification. As indicated by the dotted lines in Figure 2 and the sectional Figure 4, the section of the housing 10 devoted to the liquid volume, is sufiiciently large relative to the porous body 14 to permit even and complete distribution of the liquid at constant pressure to the absorbent pad 16. This distributed and controlled flow of liquid is transmitted to the absorbent pad which projects downwardly between the clamping bars 18 and is smoothly supported by the fabric cover 20. The projecting segment of the absorbent pad 16 should be equal in width to that of the moving surface to be coated and not depend upon the cover 20 to do any part of the liquid distribution. No brackets or other supports are shown to hold the apparatus in contact position with the moving surface, as they are well known and do not form a part of the invention.

Repeated or sustained use of the applicator will wear or clog the pores of the fabric 20. It is, therefore, designed to be easily replaced with the same or other material to assist the operation. The groove 22in the side rails 24 of the reservoir body are fashioned to receive the extended fabric as shown in Figures 3 and 4. In Figures 1 and 2, the cover 20 is shown only in small sections to indicate position and coverage; otherwise, it is deleted from these figures for clarity of the remaining detail. Resilient fasteners, such as the springs 26 are mounted on each end of the reservoir housing to stretch the wires 28 in the grooves 22 to hold the fabric closely against the bottom of the absorbent pad.

In the preferred embodiment, the device is used under conditions of atmospheric pressure aided only by the static head of the liquid filling the reservoir and the supply source. It'is evident to those versed in the art that additional pressure can be applied through the tapped aperture 13, or the source, and the device used in the inverted or other position to coat surfaces as desired. The use for which this applicator is designed, namely coating the upper surface of a moving body in a production line, such as a moistener for seals, or applying an antiadhesive liquid to commercial items prior to packaging, requires the device to be used as indicated in Figure 2 of the drawing.

Under such conditions, particularly in the application of an anti-adhesive to prevent sticking, as in packaging wax cakes, excessive amounts of the liquid may adversely afiect the item or damage the container. It is required in such cases to apply predetermined quantities of the liquid as a coating on the surface of the wax cakes to be packaged which will be in contact with a like surface of another cake. A liquid for this purpose is described and claimed in an application Serial Number 190,057, filed October 13, 1950 now Patent No. 2,643,973.

The porous member of the preferred embodiment is built up by assembling a plurality of comparatively thin members of uniform porosity. Any material having this Patented Dec. 18, 1956' porous metal, etc. However, the available porous metal sheets used commercially aslubricant absorbing bearq .Mit o mayb used s h. a pressed bre. WOW! =-a Y-, el a a t do. itb rut ss -r, Oth r; I porous metal sheets such asthosegmanufactured bythe:

pressing of dry,metal filings;.andptherprocesses, are es;

form flow of liquidto supply the exact amount of coating .to a ,surfacemoving beneath and in contact .with. the

a r-moan.

fabric cover. over. the, area, of, the absorbent pad, is

the result- An .applicatiomof the. device. usableias an, example is Q found in coatingwax cakeswitha nonstickingpreparation preliminary-to packaging .in cardboard cartons for remove a quantity of the liquid from the absorbent pad commensurate with the feed of the liquid through the porous member. As the operation is continuousand uniform the proper amount of liquid is received on the wax cake surface. If wax particles and other foreign. material should eventually. clog the pores of the fabric cover it may be necessary for this reason to renew it. However,..the effectiveness of thefabric cover istvery seldom affected by cloggingwithvforeign material, but is. normally worn out in contact and replacement. is. needed only at longintervals. It is used-primarily, in our example, to keep the wax cakes free of hairs from the felt pad, retain the operating dimensions of the felt absorber, and -as noted -to give an interchangeable wearing surface protecting the :pad from undue wear and tear. Provision has been made for easily renewing this part of the device.

storageandshipment. oil for this. purpose is,dis

closed in the application o f.referen ce. and,is noted ascovering. a. wideyrange, of viscosities. Such a liquid is supplied to thereservoir, space of the housing 10 indirect contact with the ,porousfmemberli; A simple float control arrangementmaintains the reservoir full of the liquid underconstant pressure at all times. The thickness or number of layers of material in the porous mem ber 14 isdetermined to transmit the proper. flow of liquid to coat the wax cakes. As the most desirable location of the device inthis example is adjacent the extrudernozzle in order tocoat the moving'surface before the wax cake is distorted'by cooling, it is fastened to existing structure of the extruder by simple brackets. The dimensions of the absorbent pad 16, projecting down-.

Ward from thehousing 10fare suchas to give a ,width equal to the wax cake and, alength along the waxcake ribbon to form an area capable of supplyingsuflicient liquid to the continuously moving surface.

In this example, it hasb'een determined to coat the wax cake. surface (12" x 18.) with 1 cc. of anti-adhesive liquid. By test, it has. been determinedjthat this quantity will prevent objectionable adhesion. and will not wet the containers with consequent weakening in stor:

age or transit. This flow, for the particular liquidused and under the conditions of operation, is obtainedby a definite number of'porous metal plates, each of a specified thickness. Under one condition of 'operation, this number was found to be one of a commercially available plate .062 inch thick. The invention is not restricted to this particular material,- but will also use wood, fibre, and other materials capable of manufacture. into uniform porous sectionsas indicated.

The feed of the liquid through the porous member to the absorbent member having been established, the fabric cover 20 is the contacting surface withwhich the wax cake surface rubs as' it passes beneath the applicator. The absorbent pad used was of felt which was. covered by a piece of muslin. The wax cakes, of our example,

From the above description and example, it is apparent that-an apparatus isprovided which willlcoat a moving surface ,uniformlyawith a liquid. The arrangement ofthe liquid-flow .cohtrolimembers betweentheliquid, supply. and-the moving surface issuch as to evenly. dis-Jr tribute the required. quantity .of yliquidnninterruptedly fortlongperiods oftimeasrequired by production line methods. Furthermore thea apparatus provides aneasilyw assembled,; repair-free applicator.- requiring; no mainte. nance, whichwill ifunctionuniforrnly in the desired man? ner; V

What-is claimed; is:

An applicator for; cont-rolledcontinuous application of: liquid, to surfacesmoving relatively thereto, the same comprising an elongated open bottomed housing the top ofwhichjs.providedwith a constantly open orificefor continuous inflow. of liquidpa pad and above it. a pervious. liquiddistributor. closingthe bottom. of the housing; clamping bars extending, along the bottoms of the. side walls of the housing and confining said pad againstsaidi distributor and said distributoragainst shoulders formed; on said side walls, thespace between the distributor and the top of the housing forming a reservoir .adapted to be completely, and continuously filled by the continuousinflowingliquidrthe, pad, secured to the housing as specified, projectingbelowthe housing, and a fabric sheet for contactwith said moving surfaceextending-underthe; padj-and under the c1amping; bars withits longitudinal; edges secured;to,the opposite longitudinal walls of the housing. .7 a

References Citedin the. file of this patent UNITEDjSTATES, PATENTS 135,949

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