US 3160685 A
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Description (OCR text may contain errors)
Dec. 8, 1964 Filed Sept. 2l, 1961 L3/ffl /B gli 29 C- W. CHASE SWING DIFFUSER 2 Sheets-Sheet l EL-gado?? mmfm/w ma@ Dec. 8, 1964 c. w. CHASE 3,150,585
SWING DIFFUSER Filed sept. 21, 1961 2 sheets-sheet 2 'EQ-jg A9@ @D @if QN@ 55 52 Ewa/ufo? nited States Patent Office arenas Patented Dec. 8, 1964 3,153,685 SWNG DEFFUSEB Carson W. Chase, @ak Park, ill., assigner to FM@ Corporation, a corporation of Delaware Fiied Sent. 21, i951, Ser. No. 139,703 3 Claims. (Ci. iol-i124) The present invention relates to a swing dfuser for aerating liquid, such as sewage, in a tank, and is particularly concerned with a piping and linkage arrangement by means of which the aeration is accomplished more emciently than possible with previously known apparatus.
Swing dilfusers comprise a stationary header in ow communication with `a source of air under pressure, a pm'r of hanger pipes, and a diffuser header immersed in the liquid being aerated. In the present application the term upper hanger pipe will refer throughout the speciiication and claims to the hanger pipe that is uppermost when the swing diffuser is in its operating position with the diffuser header in its lowermost position. The term lower hanger pipe will always refer to the hanger pipe that is lowermost when the swing diffuser is in said operating position.
Heretofore diffuser headers in swing diifusers have been limited to a length of approximately sixteen feet. The excessive weight of units of greater length and the loss or" air pressure due to air friction made it uneconomical to supply proper air pressure throughout the length of longer units. Very large quantities of air are required for treatment in large sewage treatment plants. The cost of compressing air is, next to the cost of labor, usually the largest operating cost. Since cost of compressing air is approximately proportional to the compressed pressure, any increased air pressure required at the compressor7 due to frictional iiow loss between the compressor md the header, increases both operating costs and the original cost of air compressing equipment.
Swing diiusers previously known have been characterized by pivotal connections between the ltwo hanger pipes and between the upper hanger pipe and the stationary header. The meeting surfaces of each of these pivotal connections are machined to a smooth finish to provide air seals and to reduce the surface friction between the moving parts. Each pivotal connection is characterized by a sharp right angle bend in the passageway for air owing through the diffuser. The right angle bends in the direction of air flow at the pivotal connections cause considerable air friction in the swing diffuser.
In accordance with the present invention the pivotal connections of the upper and lower hanger pipes cornmon to swing diiusers of the prior art are replaced by exible connections. The liexible connections are formed by flexible tubes and by pivoted guide members that help control the pivotal movement of the hanger pipes. One iiexible tube has one end secured to an outlet in ilow communication with an air main or other source of air p under pressure, and its other end secured to the upper end of the upper hanger pipe. The other flexible tube has one end secured to the lower end of the upper hanger pipe and its other end to the upper end of the lower hanger pipe.
The flexible tubes providing the connection between the upper hanger pipe and the air source and between the upper and lower hanger pipes are preferably plastic or elastomeric. The tube connecting the upper hanger pipe to the source of air is provided with a flexible steel shield that protects it from deterioration due to the suns rays and also prevents it from buckling too sharply in the center of its bend.
The flexible connections of the hanger pipes permit the air to flow smoothly from the air main to the T fitting at the diffuser header in a single vertical plane. The smooth liow path for the air eliminates a substantially large pressure loss due to air friction in the pivotal joints of swing dilfusers of the prior art. The exible tubes also redu the total weight of the swing diffuser. The
K decrease in weight and the reduction in pressure loss permit the use of diffuser headers of approximately twice the maximum length heretofore used. T he use of longer headers permits the diffusion of more air from each swing assembly, and therefore fewer swing assemblies are required in a tank. The use of fewer swing assemblies per tank reduces both the cost of installation and the maiutenance cost for the diffuser equipment. Y Y
The flexible tubes also eliminate the need for expensive machining of the meeting surfaces at each of the pivotal joints. The elimination of the pivotal joints having surface to surface contact between smoothly machined surfaces also eliminates the need of lubricating the parts at said joints. The flexible tubes are secured to the ends of the pipes to form airtight seals. The ends of the pipe sections are spaced from each other, and all metal to metal contacts are eliminated from the passageway through which the air ows.
The guide members cooperate with the hanger pipes to restrict the movement of the hanger pipes toa single vertical plane. The upper guide member is a rigid structure having one end rigidly secured to the upper hanger pipe adjacent its upper end and the other end pivotally secured to a stationary anchor member to form a swing joint. The lower guide member, which comprises a knee assembly for the joint between the hanger pipes, is a pivoted structure having one section rigidly secured to the upper hanger pipe adjacent its lower end and another sction rigidly secured to the lower hanger pipe adjacent its upper end.
A rigid control bar connecting the stationary anchor member and the knee assembly controls the relative positions of the upper and lower hanger pipes throughout their range of movement between their upper, or servicing, position and their lower, or operating, position. The
lower end of the control bar is pivotally secured to theV lower section of the knee assembly. The upper end of the control bar is pivotally secured to the stationary anchor member. The pivotal connections of the control bar to the stationary anchor member and lower guide member are so located, relative to the pivots about which the guide members are adapted to swing, that straight lines connecting the four pivot points without crossing forma parallogram in all positions of the hanger pipes except the dead center position in which all four pivot points are in alignment.
The four pivot points are so arranged Vthat when the swing assembly is being raised, the pivot points do not move into alignment until the diffuser header has been lifted above the liquid level of the tank. lf the diffuser header is still immersed in the liquid of the tank when the pivot points move into alignment, the direction of the pivotal movement of the lower hanger pipe from the dead center position is not certain.` The buoyancy of the header, together with forces exerted by fluid currents in the tank may reverse the direction of the pivotal movement of the lower hanger pipe as the pivotal movement of the upper hanger pipev is continued past the dead center position in which the hanger pipes are extended with all pivot points aligned. Such reversal will cause the lower hanger pipe to swing outwardly instead of inwardly as the upper hanger pipe is moved upwardly past dead center position. Such outward movement of the lower hanger pipe will not move the diffuser header into its servicing position, and will probably damage the mechanism.
lf the diuser headeris clear of the liquid at the time the four pivot points move into alignment, the direction diffuser header makes it necessary to provide means sta-V bilizing the header against the varying or fluctuating forces of buoyancy and of fluid currents in which it is immersed. Such means may comprise legs, tie rods, latch means, etc., or a combination of such means.
. Legs or tie rods prevent the header from sagging in a dry tank, and are adjusted (in a dry tank) to produce Y an upward force on theV header and a resulting, resisting,
elastic bending moment in the header structure inboard of the point of attachment.
Even in the case of a long, flexible, buoyant header, the lifting effect of buoyancy and fluid current forces is resisted by the said resisting elastic bending moment so that the leg is not lifted; nor is the point of attachment of the tie rod lifted. Thus, at the point of leg or tie rod attachment, the header is not deflected upward by buoyant or current forces. Upward header deflection is limited-to the free length of header and is greatly'reduced by the reduced free header length. ln the case of leg the legs therefore remain in firm stabilizing Contact with the tank floor.Y
Consequent reduction of header deflection makes it possible to adjustV the entire length of header to essentially the same depth of submergence. Deiiection of the header amounting to no more than two inches impairs uniformity of air distribution because of the dilference in water pressure at different depths.
Rollers are mounted to form the lower end of the legs to facilitate movement of the dilfuser header to its desired position.
If tie rods are used in combination with legs, the tie rods prevent the legs from dropping as the header is raised and the force exerted upward on the legs at the floor of the tank drops off. Thus, the tie rods reduce the length of rolling of the rollers as the header is raised or lowered and also reduce the 4force which must be supported by the rollers.
Instead of having supporting legs intermediate the length of the diffuser header, the header may be held in proper position by suitable latch means. When latches are used they are positioned to engage theheader at points spaced to prevent deliection of the header.
The structure by means of which the above noted and other advantages of the invention are atained will be described in the following specification, taken in conjunction with the accompanying drawings showing a preferred embodiment of the invention, in which:
FIG. l is a side elevational view of a swing diffuser embodying the invention, with the diffuser in its lowermost or operating position;
FIG. 2 is a fragmentary front elevational View of the swing diffuser shown in FIG. l;
FIG. 3 is a fragmentary front elevational view of a swing diffuser showing cables attached to the fitting adjacent the diffuser header to prevent the header from swaying;
FIG. 4 is a fragmentary front elevational view of a latching mechanism for holding the diffuser header against swaying;
FIG. 5 is a cross sectional View of the latching mechanism of FIG` 4;
FIG. 6 is a fragmentary top plan view showing the means for securing one end of the shield to a fixed support;
FIG. 7 is a fragmentary side elevational view of the i structure of FIG. 6 with the apparatus in operating position; and
FIG. 8 is a view similar to FIG. 7 with the apparatus in servicing position.
Referring to the drawings, a tank 2 comprising a floor 3 and a plurality of vertical walls 4 has a coping 5 extending from the upper edge of one vertical wall to provide a groove o in which an air main '7 is positioned. Air main 7 is provided with an outlet 8 extending toward the upper edge of the coping. The specific arrangement of the air main is illustrated merely as an example of a suitable structure for use with the swing iffuser, and it will be understood that neither the structure of the tank nor the specific arrangement of the air main is considered to constitute any part of the invention.
A. stationary anchor member 9 is mounted in fixed position on the upper edge of coping S adjacent outlet 8. The anchor member 9 is fixed to coping 5 by any suitable Y means. It may be embedded in the concrete forming the wall, or may be lixed by bolts or similar fastening means. The anchor member is preferablyy formed of metal plates, but may be cast or molded of any suitable material. As shown in the drawings, anchor member 9 comprises two side Walls 10 and il connected at one side by an integral bridge member l2. rl`he lower edge of bridge member 12 is located in a. horizontal plane above the horizontal plane of the upper edge of the coping and is spaced on the side of anchor member 9 closest to the air main 7.
An upper guide member in the form of a bridle i3 is pivotally secured to anchor member 9 by pins or studs 14 and 15 to form a swing joint for an upper hanger pipe 15. Bridle 13 is a rigid assembly comprising side walls 17 and i8 connected by an integral bridge member i5? and a plate Ztl at the lower ends of the side walls. Plate Ztl is apertured to fit around the upper end of upper hanger pipe le to whichit is permanently secured. Pin 14 extends through side walls l@ and 17, and pin i5 extends through side walls 11 and 18 to provide a fixed pivot for bridle i3 which moves pivotally in a vertical plane. Bridge member 19 extends approximately vertically on the side of bridle 13 most remote from coping 5 when the Y 'diffuser is in its lowermost position.
An upper flexible tube 2l has one end sealed to outlet 8 and its other end sealed to the upper end of upper hanger pipe le to form a flexible joint between the air and the upper hanger pipe. Tube 2l may be made of any suitable plastic or rubber composition and may be reinforced, if desired. One example of a suitable material for the flexible tube comprises nylon coated on both surfaces with neoprene. The reinforcement, if used, is preferably embedded in the nylon, and may comprise a helically wound wire or a plurality of wire rings spaced longitudinally of the tube. lt is also possible to provide integral annular ribs as reinforcement for the tube. The reinforcement, if used, must not impair the ilexibility of the tube. Flexibility is an essential characteristic of the tube because the tube must provide a ilexible hinge for the eswingjoint and for the joint between the upper and lower hanger pipes.
Upper hanger pipe i6 is in the same vertical plane as outlet 8, and upper flexible tube 21 provides a passageway for a smooth ow of air from the outlet to the upper hangerpipe. The upper exible tube extends between side walls 1t? and l1 of anchor member 9 and between side walls 17 and 1S of bridle 13. Bridle i3 is rigidly attached to upper hanger pipe lr6 in any suitable manner, as, for example, by welding. Anchor member 9 and bridle 13 cooperate to prevent lateral displacement of tube 21 and maintain it in the same vertical plane as outlet 8 and upper hanger pipe 16.
The end portion of upper flexible tube 2l adjacent outlet 8 extends over the upper edge of coping 5 between the side walls of anchor member 9. Bridge member 12 is spaced far enough from the edge of coping 5to permit the upper flexible tube to extend through the space between the lower edge of bridge member 12 and the outer upper edge of coping 5. Leveling screws 22 are provided to hold anchor member 9 at the desired height relative to the top of coping 5. Ametal plate 23 embedded in coping cooperates with screws 22 to hold the anchor member in place. Y
A flexible shield 25, preferably of metal, is mounted to engage one side of ilexible tube 21. The shield protects the upper flexible tube 21 from the sun and also prevents -it from bending too sharply. One end of shield 25 is secured to bridge member 19 in any suitable manner. The other end of shield 25 is connected to outlet S by a pair of links 26 and a pair of springs 27 as shown in FIGS. 6, 7 and S. Each spring 27 has one end pivotally secured to a pin 28 projecting laterally from outlet 3. The outer end of each pin is preferably `in the shape of a ring 28 for engagement with a loop 27 formed on the end of the spring secured thereto. Each link has a hookshaped end 26 to engage a loop 27" formed on the other end of spring 27. The end of shield 25 to which links 2d are secured is preferably reinforced by a rigid strip 25.
When the swing assembly is in operating position springs 27 are under tension, as shown in FIG. 7, and hold shield 25 against the upper surface of flexible tube 21. As the swing assembly is moved toward servicing position, the shield 25 is pushed toward the air main 7 by the bending movement of flexible tube 21, thus contracting springs 27. The pivotal connections of links 26 permit them to move pivotally about the loops 27 into the position shown in FIG. 8. In this position, springs 27 exert tension on the links in the opposite direction from that shown in FIG. 7. The springs hold shield 25 against the upper surface of ilexible tube 21 and thereby prevent tube 21 from bending too sharply as the swing assemby is moved toward its servicing position. The control of the curvature of the upper exible tube 21 maintains a smooth passageway for the ow of air from outlet 8, and thereby minimizes air friction and reduces pressure loss as the air flows through the tube when the swing assembly is in either its operating position or in its servicing position.
The lower end of upper hanger pipe 16 is connected to the upper end of a lower hanger pipe 29 by a lower tlexible tube 31'? that forms a exible knee joint. Lower flexible tube 39 and lower hanger pipe 29 are in the same vertical plane as upper hanger pipe 16 and upper eXible tube 2l. Tube 30 is similar to tube 21 but does not require a shield, such as shield 25, because it is not exposed to the sun continuously, as in the case of tube 21.
A pivoted lower guide member 31 prevents lower flexible tube 36 from being kinked when it is bent in either direction by the relative movement between the upper and lower hanger pipes. Guide member 31 comprises an upper section 32 and a lower section 33. Upper section 32 has two side walls 34 and 35 connected by an integral strip 36 adjacent their upper edges and an end plate 37. Side walls 34 and 35, strip 36 and plate 37 are fastened together and to upper hanger pipe 16 by means such as welding. Bridle member 13, upper hanger pipe 16 and upper section 32 of guide member 31 therefore comprises a light but strong and rigid assembly having one end pivoted at 14, 15, and the other end pivoted at 39, 4t), by pivot pins spaced to insure lateral stability in the plane of PG. 2. Lower section 33 of lower guide member 31 comprises side walls 41' and 42 connected by an integral strip 43 adjacent their lower edges and an end plate 44. An intermediate plate secured to walls 41 and 42 provides additional stitfening of walls 41 and 42.
Side walls 4l and 42, strip 43 and plate 44 are fastened together rigidly and to pipe 29 by means such as welding. A ange 45 is threaded or welded to the lower end of pipe 29. T hereiore, lower section 33 of lower guide member 31 and lower hanger pipe 29 comprise a light, strong, and rigid assembly pivoted to the upper pipe assembly at 39 t and 423. Pin 39 pivotally connects side walls 34 and 4i and pin 40 pivotally connects side walls 35 and 42.
Side wall 42 extends upwardly past pivot pin 4t? and is pivotally connected, as indicated at 47, to the lower end of a rigid control bar 48. Control bar 43 is curved at approximately 90 adjacent its upper end, as indicated at 49. The control bar 48 is pivotally connected to anchor member 9, as indicated at 59. The pivotal connections between the hanger pipes, the control bar, the stationary anchor member and the knee assembly are so positioned that straight lines between the pivot points 14 and Sil, 5t) and 47, 47 and 39, and 39 and 14 form a parallelogram in all positions of the swing assembly except in the dead center position in which said pivot points are in alignment. The above described relationship between the various pivot points of the swing assembly provides a positive control for the lower hanger pipe to keep it substantially vertical throughout its movement as well as when it is in either operating or servicing position. The unit may be locked in its operating position without requiring any extra weights secured to the header for counteracting the buoyancy of the liquid in which it is immersed. The uniform vertical position of the lower hanger pipe insures accurate placement of the dittusers in the tank when the swing assembly is in operating position, and insures accessibility of the headers when the swing assembly is in servicing position.
The swing assembly is lifted from its operating position to its servicing position by a lifting force applied to the rigid upper pipe assembly by a hoist or any other suitable means. The upper pipe assembly, comprising upper hanger pipe 16, bridle 13 and upper section 32 of guide member 31, is swung upwardly about pivots 14, 15 in counterclockwise direction, as seen in FIG. 1. The upward pivotal movement of the upper pipe assembly carries the lower pipe assembly upwardly, and, as the upper pipe assembly swings outwardly about its pivots 14, 15, the lower pipe assembly moves pivotally about pivots 39 and 47 in clockwise direction.
A diuser header 51, comprising two sections 52 and 53 is secured to the lower hanger pipe by means of a T- nipple S4 secured to the lower end of lower hanger pipe 29. A plurality of air diusers 55 mounted on dituser header 51 are spaced longitudinally of the diffuser header. Although the showing in FIG. 3 indicates that air ditfusers 55 extend laterally of the header, it will be understood that the air ditfusers may be mounted on the diffuser header in any desired manner. The diffuser header has a length approximately twice the length ot diffuser headers heretofore used. The added length of diuser header is made possible by the use of the exible tubes that eliminate the right angle bends of air passages through the pivotal connections conventionally provided between the pipe sections ot dituser structures of the prior art. The elimination of the right angle bends in the air passageway reduces the friction loss to such an extent that a greater flow of air is attained at a given compressor discharge pressure, thus providing uniform distribution of air throughout the diuser headers of twice the conventional length without requiring excessive air pressure at the compressor.
The header is supported on the bottom of the tank by support legs 56 provided with wheels 57 rotatably mounted in their lower ends. The wheels facilitate moving the header into proper position. The wheels furnish enough upward force to cause a torque at the center of the header that urges the ends of the header downwardly against the upward force of the wheels and keeps the wheels down against the bottom of the tank. Tie rods 58 extending between the lower'hanger pipe 29 and each section 52, 53 of the header lift the ends of the header to keep them parallel against sagging in a dry tank. The wheels do not touch the bottom of the tank until they reach their iinal position. If the header were allowed to sag, the wheels would drag across the bottom of the tank.
The wheels on the support legs and the tie rods co- 6' operate to substantially eliminate de'iection of the header. Deliection of the header of as little as two inches impairs the uniformity of air distribution because of the difference in water pressure at different heights of the' header. When tie rods and wheels are provided, the only deection of the diffuser header that can occur is at the ends of the header and is too small to matter.
The embodiment of the invention shown in FIG. 3 is substantially the same as that of FIGS. 1 and 2 except that the tie rods and support legs are omitted. la this: embodiment, exible cables 59 anchored at one end to` coping 5 have their opposite ends secured to a ring 60 attached to lower hanger pipe 29 adjacent iiange 46, Cables 59 prevent swaying of the diiuser header. When cables are provided, no extra weights are required to hold. the header in place. The header is adjusted so that its ends sag in a dry tank. When the header is immersed in liquid the buoyancy of the liquid raises the ends of the. header enough to make the header lie parallel to the bottom of the tank throughout its length.
In the embodiment of FIGS. 4 and 5, the diffuser header 51 is held in its down position by a roller latch comprising an upright standard 51 and a roller 62. Standard 61 is anchored to the iioor 3 of the tank 2 in any suitable manner, as, for example, by means of bolts 63. Roller 62 is rotatably mounted adjacent the top of the standard, as indicated at 64. The lowermost peripheral surface of roller 62 is spaced above the iioor of the tank a distance equal to the desired distance of the upper surface of the diffuser header 51 from licor.
Standard 61 is notched, as indicated at 65, to provide a shoulder 66 upon which the diffuser header is adapted to be seated. Notch 65 preferably extends rearwardly of axis 64 a distance slightly greater than the external radius of diffuser header 51. When the swing assembly is in its lowermost or operating position the diffuser header is pushed into notch 65. The depth of notch 65 permits the diffuser header to be moved to a position in which its longitudinal center is past the vertical plane of the axis 64. In this position the diiuser header is held iirmly in the desired position because the lowermost portion of the periphery of roller 62 is slightly forward of and below the uppermost portion of the periphery of diliuser header 51. Although the diffuser header may be forced out of notch 65, the pressure of roller 62 against header 51 prevents accidental displacement of the header. The header is held firmly on shoulder 66 at the desired height for efficient aeration of the tank.
While I have described a few preferred embodiments of the invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details of construction may be modied or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exact construction described.
1. In combination, a sewage tank having a floor and a standard projecting upwardly from said door, one vertical face of said standard having a notch therein, a swing diffuser comprising a rigid upper hanger pipe connected 1: to a source of air under pressure, a rigid lower hanger pipe, a flexible tube connecting the upper end of said lower hanger pipe to the lower end of said upper hanger pipe, a diiuser header connected to said lower hanger pipe, said tube cooperating with said pipes to form a passageway for the tiow of air from said source to said diffuser header, said notch being dimensioned and shaped to receive said diuser header, and a roller on said standard to hold said diffuser header in said notch.
2. In combination, a sewage tank, a swing diffuser comprising a rigid upper hanger pipe connected to a source of air under pressure, a rigid lower hanger pipe, a flexible tube connecting the upper end of said lower hanger pipe to the lower end of said upper hanger pipe,
means for providing movement of said hanger pipes, a
diffuser header connected to said lower hanger pipe, said tube cooperating with said pipes to form a passageway for the ow of air from said source to said diffuser header, guide means cooperating with said upper and lower hanger pipes to restrict the movement of said hanger pipes to a single vertical plane, and cables secured to said lower hanger pipe and the upper edge of said tank to hold said diffuser header in lixed position above the door of said tank.
3. ln combination, a sewage tank, a swing assembly pivotally mounted adjacent the upper edge of said tank, said assembly comprising an upper hanger pipe flexibly connected to a source of air under pressure, a lower hanger pipe flexibly connected to said upper hanger pipe, a diffuser header secured to said lower hanger pipe, and a roller latch for holding said diffuser header in fixed relationship to said tank, said roller latch comprising a standard projecting upwardly from the floor of said tank, one edge of said standard having a notch, the lower edge of .said notch forming a shoulder on said standard, and a roller rotatably mounted on said standard above said notch, the lowermost peripheral edge portion of said roller being spaced above said shoulder a distance slightly less than the outside diameter of said ditfuser header and forwardly of the back wall of said notch a distance slight- `ly greater than the radius of said diffuser header, whereby said diffuser header may be positioned in said notch between said shoulder and said roller, with its uppermost peripheral edge portion rearwardly of and slightly above the lowermost peripheral edge portion of said roller.
References Cited in the lile of this patent UNITED STATES PATENTS 1,219,049 Sticklin Mar. 13, 1917 1,473,160 Robbins Nov. 6, 1923 2,152,871 Charland Apr. 4, 1939 2,444,800 Aab July 1948 2,453,319 Hollyday Nov. 9, 1948 2,521,474 Morgan Sept. 5, 1950 2,527,097 Katow Oct. 24, 1950 2,650,810 Nordell Sept. 1, 1953 2,825,541 Moll et al. Mar. 4, 1958 FOREIGN PATENTS 346,270 Great Britain Apr. 7, 1931 614,617 Canada Feb. 14, 1961