US 3264683 A
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Filed May 20, 1964 8 DRYING CHAMBER GAS FLOW l BAFFLE M 6 BAFF'LE 3 1 I5 I l q 1 l 3 INVENTOR. RICHARD L. LLOYD BY ATTORNE YS United States Patent 3,264,683 DRIER Richard L. Lloyd, Salt Lake City, Utah, assignor to the United States of America as represented by the Secretary of the Army Filed May 20, 1964, Ser. No. 369,041 5 Claims. (Cl. 18-2.4)
The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.
The present invention relates to simplified apparatus for formation and drying uniformed small particles containing viable microorganisms.
Prior apparatus lacked simplicity and ability to efficiently handle particles containing viable microorganisms. The present invention is etiective and has a minimum of parts which perform in a satisfactory manner.
In the drawing the single figure is a cross-section through the apparatus of this invention.
Warm dry gas from duct 7 enters drying chamber 8 and strikes baflle 1. Baflle 1 has holes 1' therethrough so as to direct the gas in parallel paths and yet in the laminar region of flow.
An inverted dished head 2 serves as a baflle to deflect much of the warm dry gas outwardly therearound. An orifice 5 permits entrance of some of the dry gas to chamber 6' and one or more baflles at 6 serve to direct movement of the gas inside before it leaves by way of annular slot 6".
The lower section of chamber 6' comprises a dished member 3 having a nebulizer 4 in the bottom thereof. If desired this type of nebulizer may be modified to yield a greater output. The dished member 3 is smaller in diameter than inverted dished member 2 for a reason to be explained hereinafter.
A pump 9 is used to recycle diluent fluid and larger particles which are not carried out thru slot 6" into the drying chamber 8. Pressurized air is brought into nebulizer 4 thru line 10. Line 11 brings the mixture of liquids and particles from pump 9 to dish 3 and line 12 returns the mixture to pump 9, except for that nebulized by nebulizer 4, and carried out through 6". Additional diluent is introduced through valve 13 in line 14. Ad ditional make-up feed of viable microorganisms is introduced through valve 15 in line 16.
The warm gas evaporates the diluent from the particles and leaves dried uniformed small particles which .fall to the bottom of the drying chamber and are withdrawn through line 17.
Operation In operation warm dry gas is introduced through 7 into drying chamber 8. The dry gas passes through perforations 1' in baflle 1. Part of the gas passes around inverted dished baflle 2 where it creates a slight vacuum at annular slot 6" due to the venturi-like effect. Part of the gas passes into chamber 6' thru orifice 5.
A mixture of fluids and particles is pumped into the bottom of dished member 3. Pressurized air is brought in thru line 10 to nebulizer 4. The pressurized air and nebulizer create a fog in chamber 6' and the warm dry gas flowing in through orifice S and out through annular slot 6" take the fog out into drying chamber 8. The diluent is vaporized from the warmed small viable microorganisms leaving them uniformed with dried diluent as "ice they pass on out through line 17. Make-up diluent is supplied via 14 and make-up feed of viable microorganisms is supplied via 16.
If the gas is passing from 5 to 6" at a slow rate, then the larger particles in chamber 6' will drop to the bottom of dish 3 and will be recirculated via 12 and 11 by pump 9. If the gas is passing thru chamber 6' at a faster rate then slightly larger particles will flow out with the fog thru slot 6". Thus, the size of particles which will pass out and the size which will remain inside are determined mainly by the gas flow rate via 5, 6". The flow rate via 5, 6" is determined by many factors such as the rate of gas flow from inlet 7 to outlet 17, the distribution of holes 1' in battle 1, the size of orifice 5, the size of member 2 relative to the size of member 3, the size of annular slot 6", the arrangement of bafiles 6 in chamber 6', the spacing between members 2, 3 and the wall of drying chamber 8, etc. For given values of all these variables there will be an automatic classification of the particles into two sizes. One size will be small enough to be suspended in the fog and carried out thru slot 6" by the warm gas currents thru 6'. Larger particles will be too heavy and will fall back into dished member 3. If particles of a dilferent size are to be passed out thru 6" with the fog then one or more of the variable features may be changed. For example, dished members 2 and 3 may be designed to come closer to the wall of drying chamber 8 to thereby decrease the restricted area and increase the rate of gas flow past members 2, 3. This will increase suction applied at slot 6" thereby increasing the flow of gas and fog from 6' and thus withdrawing slightly larger particles.
1. Apparatus for formation and drying of uniformed small particles containing viable microorganisms comprising:
a drying chamber having an upper inlet end;
means to introduce a warm dry gas to said upper inlet end of the drying chamber;
a dish-shaped member inside of the drying chamber;
an inverted dish-shaped member above the dish-shaped member, the inverted dish-shaped member having a hole therein and being spaced slightly from the dishshaped member to form a cavity and an annular slot therebetween and having its periphery spaced adjacent to the wall of the drying chamber to produce a restriction between these members;
a nebulizer mounted in the dish-shaped member and having fluid connections to introduce fluids to the cavity to be sprayed as a fog;
and means for the escape of fluids from the drying chamber.
2. Apparatus as in claim 1 and;
a baffle in the drying chamber with holes therein to spread and distribute the gas as desired as it enters the drying chamber.
3. Apparatus as in claim 1 and;
a bathe in the cavity to direct the flow of fluids in the cavity.
4. Apparatus as in claim 1 wherein gas flowing through the restriction creates a low-pressure area adjacent to the slot such that gas entering the hole in the inverted dishshaped member, and fog from the nebulizer, are drawn out through the slot.
5. Apparatus as in claim 1 and means to supply diluent and viable microorganisms to the nebulizer whereby the diluent will provide a fluid film about the viablemicro-- organisms and whereby the warm dry gas will vaporize the fluidtherebyleaving a solid film of diluent residue encapsulating the viable microorganisms.
Wreesmann 1594 MacLachlan 1594 X Stratford 1594 X Marshall. 1594X Moor et a1." 239338 Darnell 159,4
WILLIAM J. ESTEPHENSON, Primary Examiner.