US3367542A - Device for dispensing a slurry-type additive into a liquid solvent - Google Patents

Description

Feb. 6, 1968 w. F. MADISON DEVICE FOR DISPENSING A SLURRY-TYPE ADDITIVE INTO A LIQUID SOLVENT 2' SheetsSheet 1 Filed April 6, 1966 .N Y. m% m m E 0 vM 0W m FA M m L W Y B \Q 9. E 993 J 77 i 9 W /W W \\\wy 11 L:

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DEVICE FOR DISPENSING A SLURRY-TYPE ADDITIVE INTO A LIQUID SOLVENT Filed April 6, 1966 2 Sheets-Sheet 44 42 l4 I2 2 84 58 40 L IS ,-r

INVENTORQ WILLIAM F. MADISON MMFQZO ATTORNEY.

United States Patent O 3,367,542 DEVICE FOR DISPENSING A SLURRY-TYPE ADDITIVE INTO A LIQUID SOLVENT William F. Madison, Arcadia, Calif., assignor to the United States of America as represented by the Secretary of the Navy Filed Apr. 6, 1966, Ser. No. 541,459 3 Claims. (Cl. 222193) ABSTRACT OF THE DESCLOSURE A device for dispensing and mixing metered concentrations of a slurry medium into a flowing stream of solvent comprising a pair of radially spaced concentric cylindrical shells, with one of their coadjacent ends designated the inlet ends and the other coadjacent ends designated the outlet ends. The outlet end of the inner shell forms a closed conical end portion, and the outlet end of the outer shell has a conforming frustoconical shape which is open to communicate with an outlet duct. The interior of the inner shell forms a chamber for containing the slurry medium. After a charge of slurry is placed in this chamber a floating piston is placed over the charge at the inlet end. Slurry ejection orifices are formed in the conical end portion of the outlet end of the inner shell. Pressurized solvent is admitted to the inlet end of the interior of the inner shell to act against the piston, and is also flowed through the annular passage between the inner and outer shells. The annular passage is constricted upstream of the location of the slurry ejection orifice to provide a lower static pressure where the orifices are located. The solvent acting against the piston pushes the slurry out through the ejection orifice into the solvent flowing in the annular passage.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The invention relates to a dispensing and mixing device for introducing a predetermined concentration of additive, in the form of a fluided slurry-type medium, into a confined pressurized stream of a liquid diluent medium. More particularly, the invention relates to such a device having special utility in conjunction with a torpedo drag reduction sytem of the type disclosed in the co-pending application of A. G. Fabula et al., entitled, Torpedo Drag Reduction Employing Polymer Ejection, Ser. No. 441,002, filed Mar. 17, 1965. In the latter type of torpedo drag reducing system, a water soluble long chain polymer is mixed with inducted seawater within the torpedo for ejection about the torpedo to reduce skin drag.

In the prior art, the dispensing and mixing of slurrytype additives with a liquid diluent was done by means of a separate dispensing unit and a separate mixer. Moreover the prior art forms of separate dispensing units require their own power source, mechanical or pneumatic bottle. Apparatuses of this type have required cumbersome installation, and when used in a torpedo drag reducing system the requirement for a dispenser power source imposes an undesired weight and space penalty upon the overall torpedo vehicle design.

An object of the present invention is to provide a mixing device for introducing a predetermined concentration of a slurry material into a pressurized confined stream of liquid diluent, and which forms a self-contained unit for dispensing the slurry medium, which dispensing unit is powered by the pressure of the liquid diluent.

Another object is to provide a mixing device in accordance with the previous objective, and which may be read- 3,367,542 Patented Feb. 6, 1968 ily installed in an on-line-connection within a piping system.

Another object is to provide a compact dispenser and mixer unit which requires a minimum of special requirements for its installation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is in part a central section, and in part a cutaway side elevation, of a preferred embodiment to invention;

FIG. 2 is an enlarged section taken along lines 2'2, FIG. 1;

FIG. 3 is an enlarged detail of FIG. 1, indicated by arrow 3 therein;

FIG. 4 is an enlarged axial section similar to that of FIG. 2, but showing a modified form of invention;

FIG. 5 is an enlarged axial section similar to that of FIG. 2, but showing another modified form of invention.

Referring now to the drawing, and in particular to FIG. 1, the subject of the invention is a dispensing and mixing device 10 for injecting a predetermined concentration of additive, in the form of a fluidized slurry-type medium, into a confined pressurized stream of a liquid diluent medium. An example of the use of device 10 is in the torpedo drag reducing system disclosed in the co-pending application of A. G. Fabula et al., entitled Torpedo Drag Reduction Employing Polymer Ejection, Ser. No. 441,002, filed Mar. 17, 1965. As used therein, device 10 is connected between the seawater circulation pump (20, therein) and the discharge passages (28, therein), through which the mixture of the seawater diluent and the soluble polymer slurry is expelled about the torpedo. A typical order of concentration of additive, which is desired in the operation of this system, is 0.005 part by weight of the slurry additive agent in the seawater diluent liquid. A typical flow rate produced by the seawater circulation feed pump therein is 1.0 gal./ sec. The components forming the outer casing, which provides support for all the other parts, comprise a cylindrical casing member 12, a frustoconical casing member 14, and an outlet tube element 16, all threadedly secured together in axially aligned relationship, and in that order. A closure plate 18 is removably secured to the end of cylindrical casing member 12 by means of cap screws. An axially aligned inlet pipe coupling 20 is fitted into closure plate 18, and the pressurized liquid diluent is adapted to enter device 10 through the coupling in the direction of arrow A. A11 axially aligned outlet pipe coupling 22 is threadedly secured to the remote end of outlet tube element 16, and the mixture of the liquid diluent and additive is adapted to issue forth from device 10 through same in the direction of arrow B. Pipe couplings 20 and 22 are for connection to the same size piping, which points up a feature of the device, namely that it can be simply connected in line within a given feed piping system, provided that the source of the liquid diluent has a sufficient static pressure head for operation of the dispensing and mixing device.

Referring now to FIGS. 1 and 2, a slurry storage barrel 24 is concentrically supported within outer casing members 12 and 14. In configuration, storage barrel 24 is formed by two integral axial sections consisting of an elongated cylindrical section 26 and a short frustoconical section 28, the latter being shaped to generally conform to the shape of frustoconical casing member 14. A cone piece 30, forming an extension of the conical surface of section 28, is threadedly secured to the downstream end of the storage barrel. The support for barrel 24, at its upstream end, comprises an inwardly directed annular flange 32 formed at the rear end of casing member 12.

Annular flange 32 forms a bare surface 34 which engages the outer surface of barrel 24. A small outwardly projecting collar 36 is formed at the open end of barrel 24. Collar 36 is clamped between closure plate 18 and the end of barrel 24, when in assembled condition, thereby locking the barrel against axial movement. The support for barrel 24 at its downstream end comprises a ring 38 having four inwardly projecting spacer elements 40 arranged in quadrature relationship about its inner surface. The threaded junction between cylindrical casing member 12 and frustoconical casing member 14 is adapted to provide an annular recess 42, within which ring 38 is disposed. Ring 38 is locked in place by the clamping action between members 12 and 14, upon assembly. These upstream and downstream supports hold barrel 24 and cone piece 30 with their outer surfaces in predetermined radially spaced relationship to the inner surface of the casing members. This forms an annular channel therebetween consisting of an axially extending channel section 44 and a convergent channel section 46. Axially extending channel section 44 extends from flange 32 at the upstream end of the casing to the junction of the cylindrical and frustoconical sections 26 and 28 of the barrel. Converging channel section 46 is formed between the conical outer surfaces of barrel section 28 and cone piece 30, and the interior surface of outer casing member 14. The detailed configuration of convergent channel section 46 will be described later in this specification.

Cone piece 30 has an interior cavity formed as a series of concentric bores. Reference numeral 48 denotes the overall composite configuration of this cavity. A short axial distance from the base end of cone piece 30, its outer periphery is ringed with twelve equiangularly spaced tapped holes 50, opening into the interior cavity of the cone piece. Into each tapped hole is threaded an insert 52 containing a precision aperture 54 which extends centrally between the ends of the insert. The apertures 54 are of predetermined diameter and constitute the metering and injection orifices through which the slurry material additive is introduced into the diluent liquid. A check valve arrangement is provided in cone piece 30, this valve comprising a poppet 56, which is in sliding engagement with a bore 58. Poppet 56 is urged to the left, to its closed position by a compression spring 60. The metering and injecting apertures 54 communicate between the exterior of the cone piece 30 and a small annular pocket 62. Pocket 62 is contiguous to the lateral surface of poppet 56, in the closed position of the latter. Poppet 56 moves to the right in response to a pressure acting against the face of the poppet which is suflicient to overcome the force of spring 60, and thereby opens communication between the interior of barrel 24 and aperture 54. However, the poppet will not open in response to a pressure acting through apertures 54, since such a pressure acts only on the poppets lateral surface where it cannot exert an axial force. A rod 64 is afiixed to the rear side of poppet 56. Rod 64 slidingly extends through an axial opening 66, and thence projects into the interior of outlet tube element 16. The portion of rod 64 which extends into element 16 serves as a support for a circular mixing sieve element 68, FIGS. 1 and 3.

The interior of barrel 24 forms the slurry material storage chamber 70 of dispensing and mixing device 10. The fluidized slurry material (not shown) is placed in chamber 70 by removing closure plate 18. In filling the chamber, room is left at its upstream end for placement therein of a free-floating piston 72 having a side wall or skirt. Piston 72 is inserted in barrel 24 with open interior of its skirt facing closure plate 18. Its outer circumference is in sliding contact with the inner wall of the barrel. After the slurry material is placed in the chamber and the piston inserted, closure plate 18 is bolted on. A simple port and an associated plug for closing same (neither of which shown) are provided in the wall of piston 72. The port is opened during insertion of the piston and before the closure plate is bolted, in order to bleed the air from between the piston and the slurry material. After the piston is in place, the port is plugged. Piston 72 is preferably made of a plastic material of the type adapted to exhibit a low coefiicient of sliding friction. Highly successful results have been obtained using one such plastic material, which is commercially available under the trade name Debrin. A ring of equiangularly spaced ports 74 are provided around the circumference of the barrel 24 near its upstream end. Ports 74 are disposed immediately downstream of the previously described fiange 32 of outer casing member 10. Ports 74 extend through the wall of barrel 24 and form inlets to an annular recess 76 which extends around the inner wall of easing section 10. Recess 76 serves as a manifold to introduce diluent into annular channels 44 and 46. Angularly spaced oblong ports 78 are provided about the circumference of the skirt of piston 72. At the outer periphery of the skirt, these ports 78 open into an annular recess 80 extending around the entire skirt periphery. Annular recess 80 is so spaced from the edge of the skirt that some portion of it is opposite the ring of inlet ports 74 in the barrel for all the positions of piston 72 in which its skirt covers the ports 74. The resulting configuration of ports 78 and circumferential recess 80 in piston 72, provide communication from the interior of the skirt of the piston to the ports 74, during the initial stage of the pistons downstream movement. After the piston has moved sufficiently to uncover ports 74, the diluent liquid enters the ports directly from the interior of the barrel.

Referring to FIG. 2 for a detailed description of convergent annular channel 46, it is a general characteristic of the configuration of a simple convergent annular channel of uniform Width that the channel cross section area decreases in the axial direction of convergency. However, in the embodiment of FIG. 2, there is a selective shaping of different axial sections of the inner wall of easing member 14 which causes the variation of channel cross section area along its length to depart from that of a simple convergent annular channel. An axial section 82 of the inner wall adjacent to the upstream end of easing member 14 has a frustoconical shape which is sloped with a lesser degree of convergency than that of the confronting conical surface of the barrel. As a result, the annular thickness of the channel progressively increases in the downstream direction along section 82. Adjoining section 82 is an axial section 84 which has a frustoconical shape sloped by a greater degree of convergency than that of the confronting surface. As a result the annular thickness of the channel in the downstream direction along section 84 decreases more sharply than in the case of a simple convergent channel. The downstream end of section 84 forms a neck or throat 86 in the channel annular thickness. This throat 86 is located just above the ring of apertures 54 about the cone pieces exterior. Adjoining the downstream end of section 84 and extending to the end of easing member 14 is an axial section 88 having a frustoconical shape which is sloped with even a lesser degree of convergency than that of upstream section 82. As the result, the channel annular thickness increases in the downstream direction along section 88. The effects produced by the differing degrees of convergency of axial sections 82, 84 and 88 are as follows. By causing a progressive increase in the annular thickness of the channel, upstream section 82 tends to compensate for the reduction in cross sectional area inherent to the generally convergent configuration of channel 46. The progressive decrease in annular thickness along intermediate section 84 appreciably augments the reduction of cross section due to the convergency of the channel and effectively forms an annular section providing a venturilike effect, terminating in throat 86. The increasing annular thickness provided by downstream section 88 effectively forms an annular diffusing section downstream of throat 86.

The slope of downstream section 88 of the inner surface of casing 12 approximately merges with that of the upstream end of the internal bore 90 of outlet tube element 16. At a predetermined distance downstream from the tip of cone piece 30, the internal bore 90 expands to form an expansion chamber 92 having a concentric bulbous configuration. The previously described mixing sieve element 68 is carried by rod 66 at an axial position there along slightly downstream of the axial position at which expansion chamber 92 starts. The threaded connection between outlet tube element 16 and outlet pipe coupling 22 is adapted to retain a removable insert ring 94, which forms a throat 96 of predetermined diameter C, at the downstream end of expansion chamber 92. The diameter C at throat 96 determines the back pressure against which device operates.

In the operation of the device, pressurized liquid diluent enters the upstream end of barrel 24, filling the interior of the skirt of the piston. From the interior of the piston skirt, the diluent flows through the arrangement of circumferential ports and annular manifolds 78, 80, 74 and 76 and thence into the annular channels 44 and 46 formed between the barrel and the outer casing members. The static head of the stream progressively decreases due to losses, and constriction of the cross section area of the channel. The static head is particularly decreased in passing through the annular venturi section formed by axial section 84 of the inner surface of casing member 14, as the result of the well known action of venturi-like channels in increasing dynamic pressure with a corresponding drop in static pressure. As the result of all these effects, a substantial drop in static head of the stream takes place between the point where the stream enters the interior of barrel 24, and where it flows across the metering and injection apertures 54, just downstream of throat 86. In one exemplary, highly successful operation of the described embodiment, the liquid diluent entered the rear end of the barrel with a static head of 25 p.s.i.g., and the static head of the stream was found to drop to p.s.i.g. just downstream of the throat. Also experiments have been conducted using an outer casing member 14 made of clear, transparent plastic material to observe the liquid flow. In these experiments it was found that when the device is operated at a preferred flow rate and a preferred static head of entering liquid diluent, the stream breaks into turbulence at throat 86.

As the result of the difference between the static pressure hea'd acting on piston 72 (which is substantially the static head of the entering stream) and the decreased static head of the stream where it passes across apertures 54, a pressure differential is developed between piston 72 and apertures 54 which acts to open poppet 56 and inject the slurry additive into the stream of diluent. The size of apertures 54 determine the concentration of additive in the resultant mixture. The turbulent condition of the stream where the slurry material is injected therein aids in thoroughly mixing the additive in the diluent. In accordance with known principles, the diffuser effects produced by the shape of downstream section 88 of the inner wall of casing 14, and the bulbous expansion chamber 92, serve to restore the stream to a state of laminar flow, and to recover a portion of the static head which was reduced as the result of conversion to dynamic pressure. This is desired before the stream is delivered to its point of utilization. The mixing sieve element 68 carried by rod 64 promotes more thorough mixing of the additive with the liquid diluent.

FIG. 4 illustrates a modification in which the desired difference in static pressure differential between where the stream acts on the piston and where it passes the apertures 54, is obtained by provision of a large plurality of vanes 98 on the ring 38a held in recess 42. Additionally the vanes are canted, as shown in the drawing, to impart a counter-clockwise swirl to the stream as it issues forth into the convergent annular channel 46a. The

swirling motion, which is accelerated by the inherent reduction of channel cross sectional area in the direction of the channels convergency, aids in the mixing of the additive with the liquid diluent. The principal source of static pressure drop in this embodiment is the blocking of the passage area by the width of the vanes 98. In this instance the inner surface of casing member 14a has a single slope 100 up to the point at which the apertures are located, and a less convergent slope 102 downstream of that point.

In FIG. 5 there is illustrated an alternate form of slurry injection geometry and check valve arrangement for use with the scheme of obstructing the channel area by canted varies of FIG. 4. In this instance, the cone piece 30b is formed of two threadedly joined sections 104 and 106, and its hollow interior cavity 48b extends into the tip of the cone piece. The slurry material from storage chamber 70b is admitted into interior cavity 48b through a ring of small axial drilled holes 108 (only one of which is shown) concentrically arranged about the axis of cone piece 30b. In this instance the aperture area through which the slurry material is injected into stream of liquid diluent is a single central aperture 110 in the tip of the conepiece. A check valve is provided comprising a piston 112 having a stem 114 projecting from its upstream face and slideable in a bore 116. An integral axial pintle 118 projects from the pistons upstream face. The piston and its pintle are urged to a closed position in which the tip of the pintle 11-8 engages and block aperture 110, by a compression spring 120. The valve opens in response to the pressure which the slurry material in interior chamber 48b exerts upon the downstream face of the piston. A thin vent passage 122 communicates the portion of the interior cavity behind the piston with the exterior of the cone piece.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a dispensing and mixing apparatus for injecting a predetermined concentration of an additive material in the form of a slurry-type fluid medium into a confined pressurized stream of a liquid diluent medium, the combination, comprising:

(a) an inlet port for receiving the pressurized liquid diluent,

(b) an outlet port for discharging the mixture of diluent and additive material, said inlet and outlet ports being aligned about a common axis of concentricity,

(c) inner and outer radially spaced tubular members disposed between the inlet and outlet ports and coaxially aligned about said common axis,

(d) said outer tubular member comprising two axial sections consisting of a circular cylindrical section adjacent to the inlet port and a convergent frustoconical section extending from said cylindrical section in the downstream direction,

(c) said inner tubular member comprising two axial sections consisting of a circular cylindrical section substantially co-extensive with the circular cylindrical section of the outer tubular member and a conical section extending from said cylindrical section in the downstream direction and substantially co-extensive with the frustoconical section of the outer tubular member, said inner and outer tubular members forming an annular channel therebetween having an axially extending section formed between the cylindrical sections of the outer and inner tubular members and having a convergent section formed between the frustoconical and conical section of the outer and inner tubular members, respectively,

(f) a piston slideably engaging the interior wall of the circular cylindrical section of the inner tubular member dividing the interior of the inner tubular member into a liquid pressure chamber at the upstream side of the piston and an additive material storage chamber at the downstream side of the piston,

(g) means located at the end of the tubular members adjacent to the inlet port for simultaneously supplying the pressurized liquid diluent to the annular channel and to the liquid pressure chamber behind the piston,

(h) said conical shell section of the inner tubular member having at least one additive injection aperture extending through the wall of the inner tubular member for communicating the additive material from the additive material storage chamber to the exterior of the conical section of the inner tubular member, and

(i) means for reducing the static pressure of the stream of liquid diluent between the inlet port and the point at which the stream passes across the one or more additive ejection ports whereby the piston is actuated by the difference in static pressure between these points to eject the additive material through the aperture into the stream of liquid diluent.

2. Apparatus in accordance with claim 1, wherein:

(j) said additive injecting apertures comprise a ring of apertures formed in the wall of the conical section of the inner tubular member in equiangularlyspaced arrangement thereabout, and

(k) said means for reducing the static pressure of the stream of liquid diluent comprises the sides of said convergent section upstream of said ring of apertures forming a venturi-like channel of progressively decreasing annular thickness and terminating on a throat adjacent to the ring of apertures.

3. Apparatus in accordance with claim 1, wherein (I) said means for reducing the static pressure of the No references cited.

BENJAMIN A. BORCHELT, Primary Examiner.

25 P. A. SHANLEY, W. KUJAWA, Assistant Examiners.

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