US3345931A

US3345931A - Venturi ejector including automatically movable disc members

Info

Publication number: US3345931A
Application number: US578869A
Authority: US
Inventors: Bruce R Walsh
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1964-12-03
Filing date: 1966-09-12
Publication date: 1967-10-10
Anticipated expiration: 1984-10-10

Description

B. R. WALSH Oct. 10, 1967 VENTURI EJECTOR INCLUDING AUTOMATIC-ALLY MOVABLE DISC MEMBERS .Original Filed Dec. 5, 1964 M/VE/VTQP BRUCE 2 W41. SH

United States Patent 13 Claims. (Cl. 9878) ABSTRACT OF THE DISCLOSURE A pair of convex discs are maintained in spaced-apart relationship with the convex surfaces facing each other. One of the discs has a central opening through which exhaust gases are withdrawn. Means are provided for automatically adjusting the distance between the convex facing surfaces of the discs in response to the movement of the surrounding atmosphere.

This application is a division of Ser. No. 415,713, filed Dec. 3, 1964, now abandoned.

This invention relates to venting apparatus adapted to utilize the wind to assist and promote the removal of gases from flues, stacks, chimneys or exhaust pipes. The venting apparatus of this invention is adapted to utilize ambient air movement to assist in the removal of exhaust gases from various sources including furnaces, chemical reactors, turbines, and internal combustion engines. The apparatus of this invention can also function as a ventilator which utilizes ambient air movement to promote removal of stagnant air from enclosed spaces. The apparatus can be adapted for use in areas other than venting. For example, it could be utilized as a component in a pneumatic control system.

The apparatus of this invention comprises a pair of saucer-like discs whose convex surfaces face each other and have support means to maintain them in coaxial spaced-apart relationship, while permitting at least one of said discs to move towards or away from the other. One of the facing discs has a central opening and the apparatus is adapted for horizontal disposition of the discs on the top of a vertical stack so that exhaust gases discharging from the stack pass through said central opening. The convex facing discs define a circular venturilike throat which is open along a 360 degree are to accept ambient air currents from any direction. The apparatus is therefore installed in a locale which is exposed to atmospheric air currents approaching from all directions.

The circular venturi-like throat restriction is defined inthe space between the central regions of the convex facing discs, which is the region of narrowest separation between the facing discs. The velocity of air movement in the space between the discs is a minimum at the periphery of the discs and is a maximum at the venturi throat restriction at the center of the discs, whereby a region of reduced pressure is induced at the center of the discs. One of the discs has a central opening through which exhaust gases are exposed to this reduced pressure region, whereby the apparatus promotes the removal of these gases. If desired, each of the facing convex discs can have a central opening with each opening having an exhaust pipe extending thereto. In this manner, the removal of exhaust gases from separate sources occurs at a single venturi throat restriction.

The venting apparatus includes means for adjusting the distance between the facing convex discs to insure that the size of the venturi defined by the discs provides a substantial venting effect. At any particular velocity of air relative to the apparatus, a specific distance between the facing convex discs will provide an optimum venting effect and the adjusting means can provide this specific distance. Upon change of air velocity to another level, the adjustment means permits changing the distance between the opposing convex surfaces to provide an optimum venting effect at the new velocity level.

The apparatus of this invention is adapted so that the spacing between the facing convex discs is automatically and continuously adjustable in response to variation in the velocity of the ambient air relative to the discs. One or both of the discs is adapted to automatically move in relation to the other upon an increase in wind velocity and the direction of movement of a movable disc upon an increase in wind velocity can be toward or away from the other disc. Movement of the discs toward or away from each other upon an increase in wind velocity results in a decrease or increase, respectively, in the size of the venturi-like throat defined in the space between the central regions of the facing discs. If automatic movement of at least one disc relative to the other is to proceed, at least one disc must be freely slideable with respect to the disc supports within an established range of movement and the disc supports must be free of means for securing or obstructing a moveable disc against lineal movement with respect to the other disc within the established range.

The direction and extent of automatic movement of a moveable disk is established by the degree of curvature of the surface covering the concave interior of the movable disc. For example, if the surface covering the concave interior of a movable disc is substantially flat, the velocity of the wind over said surface will not result in a marked reduction in pressure along said surface so that the negative pressure produced at the venturi-like throat between the two facing convex venturi-defining discs will establish a force causing the movable disc to float toward its facing convex disc. On the other hand, if the surface covering the. concave side of a movable disc possesses a substantial degree of curvature so that its radius of curvature is less than the radius of curvature of the venturi-defining surface which it encloses, the velocity of the wind over said surface results in a marked reduction in pressure thereat which can be even more pronounced than the reduced pressure in the region of the venturi, whereby a net force is produced causing the movable disc to float away from its facing convex disc.

When discs are secured at a fixed distance from each other and cannot move relative to each other an increase in wind velocity increases the eductive effect upon the flue gases. On the other hand, if the apparatus is adapted so that the distance between the discs automatically increases with increasing wind velocity, the increased eductive effect upon the exhaust gases caused by an increase in wind velocity is moderated by an enlargement in the size of the venturi-like throat, which enlargement tends to diminish wind velocity at said throat. In this manner, there is a continuous moderating influence against establishment of an increased draft due to an increase in wind velocity and the apparatus tends to maintain a constant draft upon a flue pipe in the face of increasing wind velocity. A constant flue pipe draft is advantageously conducive to stable conditions in a combustion system, such as a furnace, served by the flue pipe.

The venting apparatus of this invention can be advantageously utilized at the terminus of a vertical exhaust pipe of an internal combustion engine or a turbine engine since engine efficiency is generally improved by rapid removal of exhaust gases. Since the apparatus of this invention automatically maintains a constant draft in the face of a varying air velocity, it is especially advantageous for utilization at the terminus of a vertical exhaust pipe of a moving vehicle, such as a truck, ship, or locomotive. The exhaust pipes of moving vehicles discharge gases while the vehicle is either at rest or moving at a very high velocity. The variation in air velocity relative to the exhaust pipe is frequently not only great but also highly abrupt. For example, sudden changes in wind direction relative to vehicle movement can result in the wind velocity being alternately additive to and subtractive from vehicle velocity. The eifect of an abrupt change in wind velocity relative to vehicle movement is compounded if the vehicle itself is being accelerated or decelerated. The constant draft feature of the apparatus of this invention is adapted to maintain a substantially constant draft at the exhaust pipe even in the face of the abrupt and severe variations in air velocity relative to a vehicle which occur under these conditions.

An auxiliary but important advantage of the apparatus of this invention is that it serves to dilute and disperse noxious fumes immediately upon their being vented to the atmosphere. The high air velocity occurring at the venturi-like throat, by diluting and thoroughly dispersing fumes as they are being vented, prevents the contamination of surrounding area with concentrated gusts of noxious fumes.

Another auxiliary advantage of the apparatus of this invention is the provision of overhead cover for a chimney or stack adapted to prevent both rain or obstructive objects from falling into the stack. Furthermore, the overhead cover eflect prevents occasional downdrafts of air into a stack due to strong downward Wind currents which could blow dangerous combustion gases into the interior of a building.

These and other advantages of the venting apparatus of this invention will be apparent from the accompanying drawings in which:

FIGURE 1 is a perspective view of a stationary exhaust gas venting apparatus,

FIGURE 2 is a sectional view of a manually adjustable modification of the apparatus of FIGURE 1,

FIGURE 3 is a sectional view of a venting apparatus of this invention wherein the upper disc is adapted to automatically float upwardly with increasing wind velocity,

FIGURE 4 is a sectional view of a venting apparatus wherein the upper disc is adapted to automatically float downwardly with increasing wind velocity, and

FIGURE 5 is a sectional view of a venting apparatus adapted to ventilate gases from a plurality of sources.

In each figure, vertical pipe is an exhaust pipe associated with any equipment which continuously or intermittently discharges exhaust gases, such as a furnace, a chemical reactor, an internal combustion engine, or a turbine. Exhaust pipe 10 terminates with a discharge opening 12 which is open to the atmosphere and is exposed to atmospheric wind and air currents approaching from any direction. The exhaust pipe can emanate from a stationary source, such a a building, in which case the Wind will constitute substantially the only source of air currents in the vicinity of exhaust pipe discharge opening 12. The exhaust pipe can also emanate from a moveable source, such as a vehicle, in which case the velocity of the vehicle and the wind will both contribute to air movement relative to discharge opening 12. When the exhaust pipe emanates from a vehicle, at certain times the velocity of the vevhicle and the wind oppose each other and at other times reinforce each other.

Referring to FIGURE 1, a pair of coaxial discs 14 and 16 have convex surfaces which face each other to define a venturi-like throat 18 in the region between the centers thereof. Convex discs 14 and 16 have substantially the same diameter and the same radius of curvature. The lower disc 16 has a central opening 20 which is only slightly larger than the outside diameter of pipe 10 at pipe discharge opening 12 so that the discharge end of pipe 10 is snugly received by opening 20. The discharge end of pipe 10 is flush or level with opening 20 so that the discharge end of pipe 16 shares a common surface with lower disc 16 and does not extend above the convex surface of lower disc 16. Pipe 10 originates from a source 11 which is either a stationary source, such as furnace in a building or a movable source. such as a furnace in a moving ship.

Convex discs 14 and 16 are maintained at a fixed distance apart from each other by means of supporting rods 22. The concave interior of upper disc 14 is enclosed by a surface 24 which can be a disc having substantially the same radius of curvature as disc 14.

Air movement relative to the apparatus of FIGURE 1 due to either wind or movement of the apparatus itself, or both, causes air to flow into the space between convex disc 14 and 16. The velocity of the air begins to increase in the region of the periphery of discs 14 and 16 and reaches a maximum at circular venturi-like throat 18. The high air velocity at venturi-like throat 18 creates a reduced pressure which tends to aspirate gases from pipe 10. The exhaust gases are carried away with the moving air stream.

FIGURE 2 is a sectional view of an exhaust gas venting apparatus in which the venturi-like throat 26 is defined by substantially identical discs 28 and 30 which are not uniformly convex from the center to the periphery thereof. The facing surfaces of discs 28 and 36 are convex in the central regions thereof but tend to become concave in the peripheral regions so that in sectional view the apparatus resembles a pipeline venturi tube.

FIGURE 2 illustrates manual means for adjusting the size of venturi-like throat 26 in order to obtain an optimum eductive effect at a particular wind velocity. A rod 60 depends from disc 28. Rod 60 is provided with a terminal bracket 62 having a threaded opening extending therethrough. Complementary rod 64 rises from disk 30. Rod 64 is provided with a terminal bracket 66 having a nonthreaded opening extending therethrough. Screw 68 extends through brackets 66 and 62, but is in threaded engagement with bracket 62 only. A dowel 74 also depends from disc 28. Complementary rod 70 rises from disc 30. Rod 70 is provided with a terminal bracket 72 having an opening extending therethrough which is larger than dowel 74 so that it slideably receives dowel 74. Upon rotation of screw 68 dowel 74 and bracket 72 prevent rotation of disc 28 and permit disc 28 to move linearly relative to disc 30 whereby adjustment of the size of venturi 26 is accomplished.

The exhaust gas venting apparatus of FIGURE 3 is adapted so that upper disc 32 is automatically movable away from lower disc 34 with increasing wind velocity whereby the venting draft at discharge opening 12 of pipe 10 is maintained substantially constant in the face of increasing wind velocity. Facing convex discs 32 and 34 define a venturi-like throat 36 in the region of smallest separation between said discs. Enclosure disc 33 covers the concave side of convex venturi-defining disc 32. Enclosure disc 38 has a smaller radius of curvature than the radius of curvature of venturi-defining disc 32. For purposes of comparison, line 40 defines the position of an imaginary enclosure disc surface having the same radius of curvature as disc 32.

Rods 42 each terminate with a lower knob 44 and depend from upper convex disc 32 while pipes 46 which are open at both ends extend upwardly from openings in lower concave disc 34. Each rod 42 extends through its associated pipe 46 and is freely movable upwardly relative to its associated pipe 46 until knobs 44 reach disc 34. When there is no significant atmospheric movement relative to the apparatus, convex disc 32 rests upon the upper end of pipes 46. Upon occurrence of a significant air velocity relative to the apparatus, air flowing between convex discs 32 and 34 reaches a maximum velocity at venturi-like throat 36 and creates a reduced pressure thereat which tends to assist withdrawal of exhaust gases from pipe 10. Ordinarily, increasing wind ve- .locity tends to increase the eductive effect at venturilike throat 36 by inducing an increasingly great pressure reduction at throat 36. However, because of the high degree of curvature of enclosure disc 38, air movement along enclosure disc 38 concomitantly produces a reduced pressure in the region above enclosure disc 38 and, because the radius of curvature of enclosure disc 38 is smaller than the radius of curvature of convex disc 32, a net upwardforce can be created causing convex disc 32 to float upwardly. As disc 32 floats upwardly, the size of throat 36 increases which in turn reduces the velocity of air movement at throat 36 and thereby moderates the pressure reduction at 36. When the wind velocity decreases from a high level, the net lifting force upon upper disc 32 is reduced and disc 32 floats downwardly, thereby reducing the size of venturi throat 36 and compensating for the reduction in wind velocity. In this manner, the apparatus of FIGURE 3 is advantageously adapted to control the eductive venting effect at exhaust pipe discharge opening 12 and to maintain the eductive venting effect at a constant level regardless of wind velocity.

The apparatus of FIGURE 4 is adapted so that upper convex disc 48 automatically moves closer to lower facing convex disc 50 upon increasing wind velocity whereby the control eifect of the apparatus of FIGURE 4 is directly opposite to the control effect of the apparatus of FIGURE 3. Rods 52 depend from upper convex disc 48 and extend through associate-d openings in lower facing convex disc 50. Rods 52 etxend longitudinally through springs 54, which are disposed entirely between facing convex discs 48 and 50 to establish the size of venturi-like throat 56 during a no-wind condition.

Springs 54 are normally in neither substantial tension nor compression. Enclosure disc 58 covers the concave side of upper convex disc 48 and is substantially flat or has a much larger radius of curvature than convex disc 48. When the air is still, upper convex disc 48 is supported by springs 54. Upon increasing wind velocity, a reduced pressure is created between facing convex discs 48 and 50. Since enclosure disc 58 is flat and substantially free of curvature, air movement along enclosure disc 58 does not include a significant pressure reduction along enclosure disc 58. The reduction in pressure between facing convex discs 48 and 50 therefore creates a net force tending to depress upper convex disc 48 against springs 54 and reduce the size of venturi throat 56. When wind velocity subsequently diminishes, a lower reduced pressure ensues between facing convex discs 48 and 50 and the compressive stress in springs 54 tends to lift upper convex disc 48.

A single apparatus can be adapted for the ventilation of gases from a plurality of sources. The apparatus of FIGURE 5 shows facing

convex discs

76 and 78 each having an opening at the central region thereof for receiving exhaust pipes from separate sources. Exhaust pipe 10 extends to and terminates at the central opening of lower disc 76 while exhaust pipe 80 extends to and terminates at the central opening of upper disc 78. An additional source of gases can be vented through the venting apparatus by disposing exhaust pipe 84 concentrically within exhaust pipe 80. The opening 86 of inner concentric pipe 84 is flush with the opening 82 of outer concentric pipe 80. The single venting apparatus of FIG- URE 5 is adapted to utilize atmospheric air currents for the removal of gases from

pipes

10, 80 and 84, respectively, each of which emanates from a separate source.

It is stated above in regard to FIGURE 1, that the concave interior of upper venturi-defining disc 14 is enclosed by a surface 24 such as a convex disc having substantially the same radius of curvature as disc 14. FIG- URE 1 of the drawing shows that the concave interior of disc 14 is entirely enclosed by the convex enclosure surface. Similarly, the drawing shows that each venturidefining disc 28 and 32 of FIGURES 2 and 3, respec tively, defines a concave hollow interior which is completely enclosed by means of an enclosure surface which also possesses a concave hollow interior and which is spaced apart from the concave interior of the venturidefining disc. As shown in FIGURES 2 and 3 the concave interior surface of the enclosure disc and the concave interior surface of the venturi-defining disc face each other across a hollow, completely enclosed zone.

Various changes and modifications can be made without departing from the spirit of this invention or the scope thereof as defined in the following claims.

I claim:

1. An apparatus comprising a pair of convex members, means for maintaining said members in spaced-apart relationship with the convex surfaces facing each other, means for permitting automatic lineal movement of at least one of said members relative to the other responsive to the movement of the surrounding atmosphere, the convex central regions of said members facing each other in spaced-apart relationship to form a circular venturilike throat therebetween and one of said members having opening means at the central region thereof.

2. The apparatus of claim 1 including a pipe whose discharge end is disposed at and is level with said opening means, said pipe extending from said opening means away from said facing convex surfaces.

3. An apparatus comprising a pair of convex members with the convex surfaces of said members facing each other and maintained in spaced-apart relationship with respect to each other, the first of said members having opening means at the center thereof, the second of said members having a concave interior facing away from said first member, a convex enclosure surface also having a concave interior for enclosing the concave interior of said second member, the concave interior of said second member and the concave interior of said enclosure surface facing each other in spaced-apart relationship to define a hollow enclosed zone therebetween, and means for automatically adjusting the distance between the convex facing surfaces of said pair of convex members in response to the movement of the surrounding atmosphere.

4. The apparatus of claim 3 wherein each of said pair of convex members are discs having substantially the same diameter and radius of curvature and are disposed coaxially with respect to each other.

5. The apparatus of claim 3 including a pipe whose discharge end is disposed at and is level with said opening means, said pipe extending from said opening means away from said facing convex surfaces.

6. An apparatus comprising a pair of convex discs, support means for maintaining said convex discs in spacedapart relationship with the convex surfaces facing each other to form a circular venturi-like throat therebetween, the first of said discs having opening means at the central region thereof, the second of said discs having a concave interior facing away from said first disc, a convex enclosure surface also having a concave interior for enclosing the concave interior of said second disc, the concave interior of said second disc and the concave interior of said enclosure surface facing each other in spaced-apart relationship to define a hollow enclosed zone therebetween, and means for automatically adjusting the distance between the convex facing surfaces of said discs in response to the movement of the surrounding atmosphere.

7. The apparatus of claim 6 including a pipe 'Whose discharge end is disposed at and is level with said opening means, said pipe extending from said opening means away from said facing convex surfaces.

8. An apparatus comprising a pair of convex members, support means for maintaining said members in spacedapart relationship with the convex surfaces facing each other to define a circular venturi-like throat therebetween,

said support means permitting automatic lineal movement of said members relative to each other responsive to the movement of the surrounding atmosphere, the first of said members having an opening ,at the central region thereof, the second of said members having a concave interior facing away from said first member, a convex enclosure surface also having a concave interior for enclosing the concave interior of said second member, the concave interior of said second member and the concave interior of said enclosure surface facing each other in spaced-apart relationship to define a hollow enclosed zone therebetween.

9. An apparatus comprising a pair of convex discs one of which is stationary and one of which is movable, support means for maintaining said convex discs in spacedapart relationship with the convex surfaces facing each other, said support means permitting automatic lineal movement of the movable disc relative to the stationary disc respon'sive to the movement of the surrounding atmosphere, said stationary disc having an opening at the central region thereof, said movable disc having a concave interior facing away from said stationary convex disc, a convex enclosure surface also having a concave interior for enclosing the concave interior of said movable disc, the concave interior of said movable disc and the concave interior of said enthe radius of curvature of said convex movable member.

closure surface facing each other in spaced-apart relation- 25 ship to define a hollow enclosure zone therebetween.

12. The apparatus of claim 9 wherein said discs are horizontally disposed.

13. The apparatus of claim 9 including a pipe whose discharge end is disposed at and is level with said opening.

References Cited UNITED STATES PATENTS 1,289,152 12/1918 Gerke et a1. 9820 2,387,708 10/1945 Arnhym 982O 3,021,811 2/1962 Feis 98-60 X FOREIGN PATENTS 476,093 12/ 1937 Great Britain. 568,286 3/ 1945 Great Britain. 838.855 6/1960 Great Britain.

ROBERT A. OLEARY, Primary Examiner.

M. A. ANTONAKAS, Assistant Examiner.