US2651724A - Machine for irradiating liquids - Google Patents

Description

Sept. 8, 1953 V. C. HALL MACHINE'FOR IRRADIATING LIQUIDS Original Filed Nov. 3, 1948 IN VEN TOR. VICTOR CT HALL ATTORNEY Patented Sept. 8, 1953 MACHINE FOR IRRADIATING LIQUIDS Victor C, Hall, Media, Pa., assignor to Merck & Co., Inc., a corporation of New Jersey Original Yapplication November 3, 1948, Serial No. 58,086. Divided and this application April 18, 19,51, `Serial No. 221,680

(Cl. Z50- 49) 4 Claims.

This invention relates to a machine for sterilizing liquids and more particularly to an apparatus of this character for destroying bacteria and viruses by the use of ultraviolet radiation.

rIhe invention has particular utility in the sterilization of human blood plasma, but it is to be understood that the apparatus may be employed equally as well for destroying bacteria and viruses in other liquids. For example, the invention may he applied for the treatment of blood serum, milk, virus vaccines, and even the purification of water.

The invention is of particular importance for the sterilization of human blood plasma for the reason that this material presents an especially troublesome problem because of the necessity of not destroying any of the properties of lthe plasma. It has been found that -plasma as it is initially obtained sometimes containsa virus which brings about a disease of the liver vin the person to whom the plasma Vis administered. Prior attempts to destroy this virus in plasma have not been satisfactory.

To make certain that all of the bacteria or virus which is present in the liquid being treated is completely killed, it is of the utmost importance that these contaminating micro-organisms be completely subjected tothe ultraviolet radiation. As the machine operates upon the .general principle of spreading kthe liquid out into a thin nlm which is exposed to the radiant energy, it is of primary importance that this be maintained of uniformly 'thin depth, Moreover, it is important that there exist no-possibility for any liquid to pass through the machine which is not exposed to ultraviolet light.

It is therefore a primary object of thepresent invention to subject human plasma to the action of ultraviolet radiation in 4such a manner that all of the contaminating virus and bacteria contained therein will be exposed with vabsolute certainty to the killing action of the radiant energy and that this occur without .any Adestructive action upon the plasma itself.

A preferred embodiment V.of the invention is illustrated in the accompanying drawings in which:

Figure 1 is a transverse ,cross sectional View through the machine.

Figure 2 is a sectional view of theV line 2 2 vof Figure 1.

Figure 3 is a perspective Vview of an end portion of the roller showing the wiper blade action.

Figure 4 is anenlarged viewof a portion of the dam.

In general, the machine consists or" a drum rotating on a horizontal axis, and having its lower portion lying in a body of the plasma which is to be subjected to irradiation. The rotation of the drum causes it to pick up a thin nlm of the plasma and to carry it with the drum in its rotation. The upper side of the drum is (.-posed to intense ultraviolet radiation from a suitable lamp cr lamps so that the virus or bacteria contained in the plasma are destroyed. Af ter the plasma has passed the source of radiation, it is removed from the drum by a wiping blade and is then delivered to a storage container.

lt has been found to be of the utmost importance that the film of plasma which is formed upon the drum be or extremely small thickness, for example, on the order of one-tenth of a millimeter, and that this hlm remain of relatively uniform thickness while it is being advanced from the pick-up trough, beneath the source of radiation and to the removing blade. The features of the machine which obtain these operations and results will become evident from the following description.

Referring now to the drawings, the drum which serves to pick up the plasma to be treated is indicated at it. The ends of this drum should be closed and it is not material whether this is accomplished by forming the drum of a solid body or by making the drum of hollow eonstruction. rirunnions ll project axially from opposite ends of the drum El? so that it may be rotatably mounted upon a horizontal axis. These trunnions l! rotate in pillow blocks or bearings lil which are carried by suitable supports i3, projecting upwardly from the base plate or table ifi..

It is preferable that the base plate Hl be elevated above the floor and this obviously may be accomplished in any desired manner. For example, the plate may merely rest upon a table, or as here shown, it may be supported by legs iii above the licor'. To rotate the drum iii, any suitable means may be empioyed. For example, one or" its trunnions li may be connected to a source of power.

To supply the plasma which is to be sterilized to the roller it, a feed pan l5 is disposed beneath the drum l. It is important to observe that the portion of this pan which is directly beneath the drum is shallow and that the bottom of the pan conforms to the curvature of Vthe drum and is disposed close to the surface of the drum. This relationship is especially true and is of primary importance at the left hand side of the feed pan as it is shown in Figure l; this being the side of the pan into which the rotation of the drum brings the surface of the drum for its initial contact with the pool of plasma. Preferably, the average radial distance between the drum and pan I6 should be less than inch. Because of this relationship, the tendency for any surging of the plasma to occur beneath the rotating drum is reduced to a minimum.

This close spacing between the drum surface and the pan surface is important because it assures the continuance of a relatively quiescent pool of plasma beneath the drum and minimizes the tendency for movement within the plasma which would tend to cause an increased thickness of the lm on various portions of the drum. Moreover, by the maintenance of a Very thin depth of plasma beneath the drum, any tendency for the occurrence of a churning action which might form bubbles, is overcome.

Moreover, by having only a small volume of plasma 'below the drum IG, greater assurance is had that the fresh, incoming plasma is picked up sooner on the drum so that the time period that it remains in the feed pan I6 is reduced to a minimum. For this reason there is little likelihood that any portion of the plasma will be retained in the feed pan I6 for an appreciable time and merely be agitated by the roller.

As a consequence, therefore, of the relationship which is established between the rotating drum and the feed pan l, a uniform and extremely thin film of plasma is constantly being formed upon the rotating drum. During the rotation of the drum this thin film maintains itself and there is no tendency for the formation of rivulets such as might occur if the liquid tended to iiow backward down the drum as it is being carried up and over the top side of the drum during rotation. These considera-tions are of the utmost importance because otherwise, bubbles or thickened portions of the plasma may be formed on the rotating drum. If this occurs, the plasma either would not receive sufficient irradiation to destroy the virus contained therein, or the plasma would be subjected to such a high concentration of radiant energy that its physical or chemical properties may be destroyed.

It is important that the plasma which is to be treated be delivered into the feed pan I5 and 'beneath the drum I0 at a uniform rate throughout the length of the drum and without the occurrence of any turbulence. For this reason the feed pan includes a sump portion I'I which is of greater depth than the portion of the pan which is disposed immediately below the drum IG. Also this sump portion extends throughout the entire length of the feed pan I6 to serve as a feeder into the portion of the pan which underlies the drum I0. The plasma which is to be treated is delivered into this sump Il adjacent to the bottom thereof through a pipe IS. This is for the purpose of causing the incoming plasma to flow into a relatively large body of the plasma within the sump I'I so that the velocity of flow of the incoming plasma is reduced and its tendency to cause turbulence within the body of plasma in sump I'I is reduced. The plasma, therefore, flows laterally throughout the length of the sump I'I and overiiows over the elevated portion between it and the portion which underlies the drum.

To further assure a smooth flow of plasma from the supply to beneath the drum and make certain that no turbulence occurs, a dam I9 is disposed in the path of flow of the plasma from the sump I'I. This dam I9, as here shown, consists of an upright blade which extends throughout the length of the feed pan I6. As an important feature of the invention, dam I9 is formed with a plurality of notches 2U in its lower edge through which the plasma must flow. This lower edge of the dam I9 should lie against or at least quite close to the bottom of the pan it to tend to hold back the plasma within the sump I'I and prevent any disturbances which arise within the sump from being carried over into the portion beneath the drum ID.

It will be observed that the plasma flows from sump I'I into pan I6 beneath the darn I9 and not over the top of the dam I9. This makes it unnecessary to accurately leve1 the top edge of the dam, and assures uniform now into pan I6 along the entire length of pan I5.

To support the feed pan I6 in proper position beneath the drum I, it is formed with outwardly extending lips 2I which rest upon the tops of upright plates I3. These plates I3 are secured to the base plate I4 in any suitable manner. Also, dam I9 is held in place in pan I6 by any appropriate means.

The pipe I8, which is connected into the sump Il, may receive plasma to be treated from any suitable source. For example, the plasma may be delivered either by gravity or by a pressure feed. ft is important that the level of the plasma within the feed pan be maintained at a substantially constant point and this may be accomplished by any common means such as by the use of a float valve, or more accurate means known in the art.

The rotation of the drum I0 within the plasma contained in the feed pan I5 causes the plasma to be picked up on the surface of the drum I0 so that a thin film of plasma is carried upwardly with the rotation of the drum. It has been found important, as a feature of this invention, that the plasma be confined to the surface of the drum inwardly from the extreme ends thereof. This is desirable because experience has indicated that any tendency for the plasma to flow back downwardly along the surface of the drum instead of remaining with it during the upward movement of the drum, occurs generally at the ends of the drum. This is probably due to the fact that some of the plasma is necessarily picked up by the end faces of the drum with the result that it flows downwardly during the rotation of the drum and combines with the plasma at the eXtreme ends of the cylindrical surface of the drum to form zones of increased thickness. As it is important that the plasma which is being treated be of uniform thickness upon the drum, it is important that this plasma which is present at the `end portions of the drum be removed before it is acted upon by the irradiation lights.

To remove the plasma from the end portions of the drum, wiper blades ,27 are attached to spring leaf metal 28. Each wiper blade 21 is preferably made of a strong, resilient, plastic material as, for example, Tefion, which is inert with respect to the plasma. The blades 21 may be attached to the spring leaves 28 by any suitable means such as the screws indicated. The opposite end of each of the spring leaves 28 is attached to an upright bracket 29 which in turn is attached to the rearward edge of the sump II.

It is also desirable that the Wiper blades 21 be of notched or stepped formation so that the end portions 30 will press against the end faces of the drum to remove the plasma which is picked up by these end faces. It `will be observed that the wiper blades 21 'are disposed immediately above the surface of the plasma so that it is removedv at once from the drum and is returned downwardly into the feed pan I6. In this manner it is apparent that the plasma which moves upwardly with the rotation of the drum is confined inwardly from the extreme ends of the drum.

It may be mentioned at this point, that it is important that the drum IB be immersed a distance of from 1A; to inch and preferably about -l-g inch in the pool of plasma, Vas this has been found important to obtain a clean wiping action by the blades 21, Thus, if the drum dips into the plasma a radial distance which is less than about 1/8 inch, it will be found that the wiping blades 21 cause variations in the thickness of the plasma nlm at the edge of its removal from the cylindrical surface. These variations in thickness at the edges of the plasma film remaining on the drum resemble lcurtain-like undulations in appearance.

The thin film of plasma which is formed upon the surface of the drum is exposed to the action of ultraviolet radiation of a specific character,

and this portion of the apparatus will be explained later. It will sumce for the present to point out that this source of radiant energy is a conventional tubular lamp.

After the plasma has been subjected to this radiant energyy it is removed from the drum by means of a blade tl. Blade 3| is preferably made of the same material as the wiper blades 2l' so that it will not mar the surface of the drum and to its resiliency will remain in contact with the surface of the drum throughout the length thereof. The removal blade 3| is carried by a iiexible supporting sheet 32 which is secured to a bar in any desired manner.

It is desirable to maintain the bar 34 and thereby the supporting sheet 32 for the removing blade 3| in fixed position so that the blade 3| will be maintained firmly against the surface of the drum i0.

This assembly, constituted of the bar 34 and the supporting sheet 32, is held in proper relationship with respect to the drum In by means of its attachment to the collecting trough 35 in any suitable manner. It may here be noted that the bottom of the collecting trough 35 slopes downwardly to a central discharge tube 36. The collecting trough 35 may be supported in any desired manner, but it is desirable that this support be adjustable so that the removing blade 3| can be brought against the surface of the drum IU with the desired pressure.

It will be observed that the removing blade 3| is disposed at such an angle with respect to the surface of the rotating drum lll that it makes an acute angle with respect to the approaching surface of the drum. This is desirable so that the.

removing blade 3| does not chatter against the moving surface of the drum and it has been found that with this relationship it will effectively remove the plasma from the surface of the drum despite the extreme thinness of this lrn. Also it will be observed that the removing blade tl is disposed on the under side of the drum lil so that the plasma nlm is upon a maximum portion of the drum to receive the radiant energy from the lamp.

It has been noted that the top of the drum It! is exposed to a source of radiant energy and that this irradiation serves to kill the Virus or bacteria which is present in the plasma. In the illustrated apparatus, this irradiation is produced by 6 means of a lamp '31. This'l'amp is an elongated tube having electrical connections at its opposite ends.

It is important that this tubular lamp 31 be disposed as close as possible to the surface of the drum le so that the maximum concentration of radiation will be directed upon the plasma. To arrange the lamp 3l in this fashion, holders 38 and Se are disposed immediately beyond the -opposite end of the drum IG. Each of these holders is formed with an opening which receives the ends of the lamp 31 and thereby supports it in. place. The projecting ends of the tube 31 are connected by individual wires to a transformer or energizing device. To support the holders 38 and 3e in their proper positions at the opposite ends of the drum lil, they are formed with lateral extensions di?.

lt is desirable that the entire portion of the irradiation lamp 31 be enclosed both for the purpose of shielding the irradiation from operators who are attending the machine, and to prevent the fall of dust within the room upon the functional Darts of the machine. For this reason an elongated hood 4| is provided and it is supported upon. the front and rear upright plates 42 and 43 which are fastened to base plate i4.

l'n order to obtain the 'maximum efficiency from the radiant lamp 3l, it is desirable that a reiiector be provided to direct the radiant energy downwardly against the surface of the drum I0: For this reason a curved reflector 44 which has a surface of a suitable composition for reflecting ultraviolet radiation, is disposed close to the drum it. For example, the reflector `can be made of polished Alzac aluminum alloy. It is desirable that this reflector 44 be formed with a plurality of openings to make certain that any heat which is generated above the drum and within the tubes, can rise and pass outwardly through louvres in the overlying portion of the hood 4|. The reflector iii may be attached in any desired manner to the internal wall of the hood as shown.

It is preferable that the plates 42 and 43 be of transparent material such as glass or an acrylic resin as Lucite so that the interior of the machine may be viewed. A tight connection is established at the vertical corners where the plates d2 and 43 meet the upright end plates The combined action of the liow regulating ram I9 and the end wiper blades 21 yassures irradiation of all of the liquid which is delivered by the drum lll from the supply to the discharge portions of the machine. This is because an extremely uniform lm of liquid is caused to be present upon the drum inwardly from the ends thereof so that every portion of the liquid being carried over to the collecting trough 35 is fully irradiated `and the contaminating micro-organisms are killed.

This application is a division of my copending application Serial No. 58,086, filed November 3, 1948, now abandoned.

What I claim is:

1. An apparatus for t'he sterilization of liquids which comprises a drum, means mounting the drum for rotation, a feed pan disposed beneath the drum for applying liquid to be treated to the surface of the drum, means frictionally bearing upon the `drum for removing the applied liquid from the end portions of the surface of the drum so that the liquid is confined to a central zone thereof, means for removing the liquid from the drum at a circumferential distance therefrom and a source of irradiation to emanate ultraviolet ligiht to the liquid during its passage between the applying and the removal means.

2. An apparatus for the sterilization of liquids which comprises a drum, means mounting the drum for rotation, a feed pan disposed beneath the drum for applying liquid to be treated to the surface of the drum, wiper blades frictionally bearing upon the drum for removing the applied liquid from the end portions of the surface of the drum so that the liquid is confined to a central zone thereof, means for removing the liquid from the drum at a circumferential distance therefrom and a source of irradiation to emanate ultraviolet light to the liquid during its passage between the applying and the removal means,

3. An apparatus for the sterilization of liquids which comprises a drum, means mounting the drum for rotation, a feed pan having a portion disposed beneath the drum and having its bottom surface conforming to the surface of the drum and disposed in close proximity thereto, the feed pan also having a laterally disposed sump portion into the bottom of which liquid to be treated is delivered to prevent surges of liquid into the portion underlying the drum, and a dam disposed beneath the sump and the underlying portion of the feed pan to distribute the liquid from the sump portion, a collecting trough disposed beneath the drum on the side toward which the surface of the drum is advancing due to its rotation, a liquid removing blade bearing against the drum to remove liquid therefrom and deliver it into the said trough, and a source of radiant energy disposed immediately adjacent the upper side of the drum for emanating ultraviolet light upon the liquid.

4. An apparatus for the sterilization of liquids which comprises a drum, means mounting the drum for rotation, a feed pan having a portion disposed beneath the drum and having its bottom surface conforming to the surface of the drum and disposed in close proximity thereto, the feed pan also having a laterally disposed sump portion into the bottom of wlhich liquid to be treated is delivered to prevent surges of liquid into the portion underlying the drum, and a dam disposed beneath the sump and the underlying portion of the feed pan to distribute the liquid from the sump portion, said dam being notched along its lower edge to evenly distribute the flow of liquid from the sump portion into the feed pan, a collecting trough disposed beneath the drum on the side toward wlhich the surface of the drum is advancing due to its rotation, a liquid removing blade bearing against the drum to remove liquid therefrom and deliver it into the said trough, and a source of radiant energy disposed immediately adjacent the upper side of the drum for emanating ultraviolet light upon the liquid.

VICTOR C. HALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,052,818 Henri et al Feb. 11, 1913 1,842,313 Chaney Jan. 19, 1932 2,280,841 Ogden Apr. 28, 1942 2,499,153 Nicholson Feb. 28, 1950

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