US 3282227 A
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Nov. 1, 1966 A. NIELSEN ADJUSTABLE VENTURI INJECTOR Filed June 22, 1964 INVENTOR. 9004; M545! United States Patent C) 3,282,227 ADJUSTABLE VENTURE INJECTOR Adolph Nielsen, Oakland, Calif, assignor to Nielsen Mfg. Co., Oakland, Calif, a corporation of California Filed June 22, 1964, Ser. No. 376,768 3 Claims. (Cl. 103-271) This invention relates to fluid injectors of the type which employ a venturi action to draw one fluid into a second fluid by using the kinetic energy of the second fluid. The invention more particularly involves a double venturi construction of the type shown in my United States Patent No. 3,011,443, where the flow through one venturi may be adjusted to control the drawing power of a fixed second venturi.
In brief, the present invention contemplates an injector construction that provides a novel arrangement of parts to control the drawing power of a double venturi. The adjustable injector herein described essentially comprises a housing having first and second coaxial sections, said sections being adjustably connected together in end-toend relationship. A venturi tube mounted within the injector is supported from the first section, being spaced from the inner walls of the housing to form an annular flow path therebetween. The second section provides a flow restricting surface complementary to a surface formed on the venturi tube, the two surfaces limiting the amount of fluid flow passing through the annular flow path. By operation of means adjustably connecting the first and second section in axial end-to-end relationship, the spacing be tween complementary flow restricting surfaces of the tube and the second section may be adjusted. The size of the venturi tube and the cross-sectional area between flow restricting surfaces is such that the greatest flow occurs through the annular flow path between the venturi tube and the injector housing, the cross-sectional area being considerably greater than that of the throat of the venturi tube. The velocity of fluid passing through the annular passage increases greatly as it passes between the complementary flow restricting surfaces, creating a region of low pressure at the discharge end of the venturi tube. The appreciable pressure drop between the intake and discharge ends of the venturi tube tends to increase the flow of water through the tube, and correspondingly increases the amount of fluid or gas drawn into the throat of the venturi tube. It will be evident that an adjustment in the connection between the first and second sections of the housing may be made to either increase or decrease the velocity of fluid flow between the flow restricting surfaces. In making such an adjustment, there will be a corresponding change in the pressure drop between the intake and discharge ends of the venturi tube, resulting in a change in the drawing power of the injector.
It is a principal object of the present invention to provide an adjustable double venturi that may be easily manufactured at a lower cost than injectors of similar kind.
Another object is to provide an injector of the type described comprising a pair of coaxial sections which fluidly communicate with an overlapping and slidable fit, and which are connected by an external adjustable means.
Another object of this invention is to provide an injector of the type described comprising a pair of coaxial sections and a threaded collar for connecting said sections and permitting an adjustment in the cross-sectional area of a main flow venturi to control the drawing power of a second venturi.
It is yet another object of the invention to provide an injector of the type described, including a housing comprised of a pair of coaxial sections, one section having a right-hand thread and the other a left-hand thread, said sections being adjustably connected by a collar having 3,282,227 Patented Nov. 1, 1966 "ice threaded inner surfaces complementing said right and left-hand threads respectively.
Other objects of this invention will become apparent in View of the following detailed description and the accompanying drawings.
In the drawings forming a part of this application and in which like parts are identified by like reference numerals throughout the same,
FIG. 1 is a longitudinal section of a double venturi injector constructed in the preferred manner contemplated by this teaching;
FIG. 2 is an elevation of the injector shown in FIG. 1; and
FIG. 3 is a section taken on lines 33 of FIG. 2.
Referring to FIG. 1 of the drawings in particular, there is shown a preferred embodiment of the invention in an injector 10 connected into a flow line by a pair of threaded leads 11 and 12. Injector 10 essentially comprises first and second coaxial sections 13 and 14, the intake end of section 13 being threaded for connection to lead 11 while the discharge end of section 14 is threadedly connected to lead 12. The near ends of sections 13 and 14 are overlapped in a telescopic fit, the tubular end 15 of section 14 being received within the sleeve 16 of section 13. An O-ring seal 17 is provided in an inner recess formed in sleeve 16 to prevent fluid leakage between tubular end 15 and sleeve 16. Sections 13 and 14 are threaded along their outer surfaces 18 and 19, respectively, and the two sections are held together by a threaded collar 20. Importantly, the threads provided on surface 18 are formed in a right-hand manner, while the threads on surface 19 are of the left-hand variety; and the inner surface of collar 20 is threaded to mate with the threads 18 and 19. Therefore, as collar 20 is rotated in a right-hand direction relative to the end of section 13 the two sections will be drawn together, the tubular end 15 sliding within sleeve 16. A rotation of collar 20 in the opposite direction will, of course, produce the opposite effect and move sections 13 and 14 axially away from each other.
In most other respects injector 10 is of a conventional construction having a venturi tube 21 disposed within the main flow passage 22 of the injector. The venturi tube comprises a pair of venturi members 23 and 24 mounted by threading each into an opening of a boss 25 formed integrally with section 13. Venturi tube 21 has a restricted throat portion 26 within the boss 25 which communicates with an injection passage 27 formed through the boss and fluidly connected to the end of an inlet conduit 28.
The interior of section 14 is defined in part by an upstream surface 29, a tapered surface 30 and a restricted passage 31. Furthermore, it will be noted that venturi member 23 is formed with a radially enlarged portion 32 near its discharge end, providing a tapered surface 33 that complements and cooperates with the tapered surface 30 to form a flow restricting passageway therebetween. The radially enlarged portion 32 is also provided with a tapered surface 34 extending radially inward and in an upstream direction relative to the body thereof, said tapered surface tending to reduce the turbulence of fluid flowing through the annular space between the venturi member and surface 29.
When properly assembled, the discharge end 35 of venturi member 23 is disposed within the restricted throat 31. This is true regardless of the longitudinal adjustment that may be effected by turning collar 20 and slidably adjusting the axial relationship and connection of sections 13 and 14. With such an arrangement, the fluid passing between surfaces 30 and 33 must necessarily pass into throat 31 before coming into contact with the end 35 of venturi member 23. There can then be no build up of pressure atthe discharge end 35 of the venturi.
In operation, and as fluid is pumped through injector the greatest flow will occur in the annular space between venturi tube 21 and the inner surfaces of sections 13 and 14, since the cross-sectional area of the annular passage between surfaces 30 and 33 is considerably greater than the throat 26 of the venturi tube. Moreover, as the fluid passes through the annular passage between the flow restricting surfaces 30 and 33 its velocity greatly increases, thus creating a region of low pressure at the discharge end 35 of venturi member 33 and resulting in an appreciable pressure drop between the intake and discharge ends of venturi tube 21. The resulting increase in the pressure drop augments the natural flow of water through the venturi tube, and correspondingly increases the drawing power of tube 21, causing a greater amount of fluid or gas to be drawn in through the injector. Expressed in another way, injector 10 has a double venturi effect, the main water flow (passing between surfaces 30 and 33) serving to boost the water flow through the throat of venturi tube 21. This principle of operation is essentially the same as that of the fluid injector described in my earlier United States Patent No. 3,011,443.
An adjustment in the drawing power of injector 10 may be produced simply by rotating collar 20 in either clockwise or counter-clockwise fashion. Since venturi member 23 is supported from section 13, surfaces 30 and 33 will be positioned either in closer proximity or more distant from each other by the mere turning of collar 20.
An adjustment in the cross-sectional area betwen surfaces 30 and 33 will, of course, produce a variation in the fluid flow through the annular passage which those surfaces define. Increasing the size of the passage, decreases the velocity of the Water passing therethrough (while also decreasing the pressure drop between the intake and discharge ends of venturi tube 21). On the other hand, a decrease in the cross-sectional area of the passageway defined by surfaces 30 and 33 will increase the rate of fluid discharged into the .throat 31, thereby increasing the pressure drop across the venturi tube 21 and increasing its drawing power.
Although not shown, it is especially contemplated that a pair of set screws may be used to lock collar 20 to one or both of the threaded ends 18 and 19. While such screws are not essential, they may provide insurance against inadvertent turning of collar 20.
It is to be realized that an adjustment in the connection between sections 13 and 14 inherently produces a change in overall length of the injector 10. However, this change in length is very small, involving a dimensional change of only approximately one-quarter of an inch. Flow lines in which injectors of this kind are normally used usually tolerate a change in length far in excess of one-quarter of an inch, and for this reason there would be no difliculty in making an adjustment of injector =10 while it is being used and connected into a flow line.
Although a preferred embodiment of this invention has been illustrated and described, various changes may be made without departing from the spirit of the invention or the scope of the attached claims, and each of such changes is contemplated.
What I claim and desire to secure by Letters Patent is:
1. An adjustable injector comprising a housing having first and second coaxial sections adjustably connected in end-to-end relation; a venturi tube mounted within said housing and supported from said first section, said tube being spaced from the inner Walls of said housing to form an annular flow path therebetween; said second section and tube having complementary flow restricting surfaces limiting the amount of fluid flow passing through said annular flow path; and a threaded collar adjustably connecting said first and second sections in axial relationship for adjusting the spacing between said complementary flow restricting surfaces.
2. The adjustable injector of claim 1 wherein the outer surfaces of said coaxial sections are threaded, one section having a right-hand thread and the other section a lefthand thread; and wherein said threaded collar has threaded inner surfaces complementing said right-hand and lefthand threads respectively.
3. An adjustable injector comprising a housing having first and second coaxial sections adjustably connected in end-to-end relation, the outer surfaces of said coaxial sections being threaded, one section having a right-hand thread and the other section a left-hand thread, said sections providing a flow passage therethrough having an intake at the end of said first section and a discharge at the end of said second section; a tubular member mounted in said flow passage and supported from said first section, said tubular member having a venturi passage therethrough coaxial with said flow passage and forming an annular flow space With the inside surface of said housing; an injection passage formed through said first section and tubular member into the throat of said venturi passage; means forming a restriction on the inside surface of said second section adjacent to but forward relative to the discharge end of said tubular member, said restriction forming means also defining an annular passage with the outer surface of said tubular member, said annular passage converging toward the discharge of said second section; and a collar having threaded inner surfaces complementing said right-hand and left-hand threads, respectively, adjustably connecting said first and second sections in axial relationship for adjusting the cross-sectional area of said annular passage.
References Cited by the Examiner UNITED STATES PATENTS 136,780 3/1873 Smith 2301l2 X 2,938,464 5/1960 Nielsen 103262 X 3,011,443 12/1961 Nielsen l03273 X MARK NEWMAN, Primary Examiner.
WARREN E. COLEMAN, Examiner.