Patent Application
20220168695
The invention relates to a Venturi tube which is different in internal structure from those generally available.
Venturi tubes are well known in the art. A traditional Venturi tube 100, as shown in
Referring to
Since Pfo is greater than Pa, Vc is less than Va. It suggests that bubbles will shrink as they move from the throat 116 to the outlet 114. However, due to the gradient of the pressure in the Venturi tube, upon leaving the throat 116, the gas bubbles will be pushed away from axis Z (the axial direction of the fluid stream), and toward the inner surface of the divergent outlet 114. Since the gas bubbles deviate from axis Z as they flow, they are less likely to dissolve in the fluid. As bubbles flow, the chance of bubble collision increases, which facilitates joining of bubbles to form even larger bubbles, as shown in
There are two factors that affect the gas dissolution rate:
1. Cross-sectional area of the throat
2. Gradient of the pressure in the Venturi tube
In addition to the lower gas dissolution rate, one major disadvantage is the size (length) of a Venturi tube, which not only limits the applications of a Venturi tube but also makes it costly to manufacture.
Accordingly, there is a need for an improved Venturi tube that enables greater gas dissolution rate. There is also a need for producing a Venturi tube of reduced size and reduced cost.
The present invention provides a Venturi tube which also operates in accordance with Bernoulli's principle, but is of different structure from that of commonly available Venturi tubes.
The Venturi tube of the present invention comprises a cylindrical tube, a first cone, and a second cone. The first cone and the second cone are mounted in the cylindrical tube and are configured so that their bases face each other and are separated by a gap. The Venturi tube further comprises a suction tube, which has an inlet and an outlet. The inlet is located outside of the cylindrical tube and the outlet is located between the first base and second base, i.e., the gap between the first base and the second base.
With the first cone and the second cone are configured as above, a fluid passageway formed between the cylindrical tube and the first cone and the second cone is of a ring shape. The ring-shaped passageway will have a larger cross-sectional area than the throat of a traditional Venturi tube and thus have a higher flow rate. Consequently, the size of the Venturi tube of the present invention can be reduced if it is used to process the same fluid flow rate as a traditional Venturi tube.
In addition, as gas is sucked into the Venturi tube of the present invention, the size of the bubbles created will be smaller than those created in a traditional Venturi tube. The overall contact area between fluid and smaller gas bubbles is greater than that between fluid and larger gas bubbles. Accordingly, the Venturi tube of the present invention used as a gas-liquid mixer will have a higher gas dissolution rate than a traditional Venturi tube.
The Venturi tube 1 further comprises a first cone 20 and a second cone 30. The first cone 20 has a first base 22 and a first opening angle θ1 and the second cone 30 has a second base 32 and a second opening angle θ2. The first cone 20 is concentrically positioned in the cylindrical tube 10 with its first base 22 facing away from the fluid-in end 12. The first opening angle θ1 is greater than the second opening angle θ2. The second cone 30 is concentrically positioned in the cylindrical tube 10 with the second base 32 being spaced apart from the first base 22 for a distance Dc. In the embodiments, the distance Dc is 1 mm to 3 mm. The second base 32 has a base diameter Db equal to that of the first base 22 and smaller than the tube diameter Dt. Accordingly, the gap Rg between the bases 22, 32 and the cylindrical tube 10 is:
In the embodiments, the base diameter Db is 0.5 mm to 2 mm smaller than tube diameter Dt. The gap Rg then is 0.25 mm to 1 mm.
The Venturi tube 1 further comprises a suction tube 40. The suction tube 40 has an inlet 42 and an outlet 44. The inlet 42 is located outside of the cylindrical tube 10 and the outlet 44 is located between the first base 22 and second base 32. In an embodiment, the outlet 44 is located between the centers of the first base 22 and second base 32 in order to distribute the sucked gas more evenly in the fluid passing through the Venturi tube 1.
In one embodiment, the second cone 30 can be truncated. The length of a truncated cone is shorter than a cone without truncation if the opening angle and base are the same. The cylindrical tube 10 can be adapted to the truncated cone to have a reduced length. Therefore, a Venturi tube 1 with a truncated second cone 30 will be shorter in length and thus be lighter and take up less space.
Referring to
The outlet 44 of the suction tube 40 is arranged between the centers of the first base 22 and second base 32, that is, the location where the cross-sectional area is a minimum. Gas is sucked from the outlet 44 to this location through the tube 40.
As liquid flows through the Venturi tube 1, gas is sucked out from the outlet 44 and forms bubbles. The volume and the pressure of these bubbles are assumed to be Va′ and Pa, respectively, when the bubbles leave the outlet 44. The volume Va′ is associated with the distance Dc between the first base 22 and the second base 32. As the bubbles continue to flow along the Venturi tube, the bubbles will shrink to volume Vc′ due to pressure increasing from Pa′ to Pfo′. When the bubble size is smaller, the gas solubility is higher. Due to the geometric shape of the second cone 30, liquid flowing through the Venturi tube creates a pressure gradient that pulls these small bubbles toward the surface of the second cone 30, that is, toward the central axis Z of the stream. Bubbles flowing around the central axis Z of the stream will have more chance to contact the fluid. As a result, gas dissolution rate will be higher than in the traditional Venturi tube 100, wherein bubbles flow away from the central axis Z.
In the Venturi tube of the present invention, the passageway through which the fluid flows is of a ring-shape. A ring-shaped passageway has a larger effective cross-sectional area as compared with a throat in a traditional Venturi tube, and thus has a higher flow rate. Consequently, the size of the Venturi tube can be significantly reduced.
As compared with a traditional Venturi tube, the present invention can be smaller. In addition, the Venturi tube of the present invention produces smaller bubbles and thus will have a higher gas dissolution rate.
It should be appreciated by those skilled in this art that the above embodiment is intended to be illustrative, not restrictive. Thus, additional modifications and improvements of the present invention are possible without departing from the concepts as described.
