Pneumatic conveying venturi for flake ice

Abstract

The particularity of this invention is that the material is injected in the divergent section of the venturi. The innovative material Conveying Venturi tube consist of two parts: the main tube and the feeding tube injecting the material by gravity, at the end of the cylindrical throat into the diffusion section. The venturi is composed of a contraction section, a throat section, and a diffusion section. This device will convey distances exceeding 120 meters. The present invention permits multiple distances conveying by easily install another Conveying Venturi System at the end of the first conveying tube for extra length of conveying.

Claims

1. A long-distance pneumatic conveyor for conveying flake ice having a converging-diverging conduit forming a venturi; said venturi comprising a bulk material inlet, a motive air inlet, and an outlet; said motive air inlet having a cylindrical first section followed in a conveyance direction by a converging conic section; said outlet having a conic section diverging in the conveyance direction followed by cylindrical second section; said venturi having a throat between the conic sections; said bulk material inlet having a first bulk material cylindrical section leading to a converging polygonal section dropping and aspirating bulk material into a downstream end of the throat along a longitudinal conduit axis.

2. The conveyor of claim 1, wherein the ratio of a throat diameter to a first section diameter is between 0.5 and 0.35.

3. The conveyor of claim 1, wherein the ratio of a throat length to a throat diameter is between 0.01 and 1.0.

4. The conveyor of claim 1, wherein a Contraction angle is between 15 and 30 degrees.

5. The conveyor of claim 4, wherein a Diffusion angle is between 2 and 15 degrees.

6. The conveyor of claim 1, wherein conveyed flake ice falls into a collecting bin from motive air separation in a cyclone separator.

7. The conveyor of claim 1, wherein motive air is separated from bulk material in a cyclone separator then fed into a second venturi.

8. The conveyor of claim 1, the converging polygonal section has an angle between 55 and 75 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in greater detail with reference to the accompanying s drawings, which illustrate a preferred embodiment of the invention and wherein:

(2) FIG. 1: Is a side view of the conveying venturi of the present invention

(3) FIG. 1a: Is a detail view of FIG. 1 showing the cylindrical throat

(4) FIG. 2: is a top view of the conveying venturi

(5) FIG. 3: is an isometric section view of the conveying venturi

(6) FIG. 4: is a left end view

(7) FIG. 5: is a right view

(8) FIG. 6: is a general side view with a cyclone separator permitting to reintroduce the flake ice in a secondary venturi c/w a blower for the motive air taken either from ambient air or reusing the disposition of the motive gas stream

(9) FIG. 7: is a top view of the cyclone separator and second venturi c/w the second1s motive blower

(10) FIG. 8: is a side view of the cyclone dimensions related to the body.

DETAILED DESCRIPTION OF THE INVENTION

(11) With reference to FIGS. 1 to 5, the venturi of the present invention forms part of a conveying system for flake ice (flake ice) material, to deliver. the product at distances. The venturi tube comprises a cylindrical inlet section 2, followed by a contraction entrance 3 into a cylindrical throat 4 and a divergent outlet section 5 followed by a circular outlet section 6. The motive air from a blower 1 is introduced in an injection tube 15 under pressure into the venturi at section 2 to be accelerated by the contraction section 3 to the throat section 4 of the venturi and expand in the divergent section 5. The high velocity of the motive air in the throat tube area 4 has the air pressure reduced slightly lower than the ambient pressure. (Bernoulli's Law).

(12) The flake ice is introduced by gravity 8 into the cylindrical inlet section 9 followed by the frustro-conical input section 10, which is circumferential joined to the face edges of the venturi divergent tube 11, 12, 13leaving a hollow section with the venturi FIG. 3. The frustro-cone circumferential 10 joint to the divergent cone 5 shall not overlap the throat diameter section at 12 and FIG. 2 15. The increased surface area at section 13 FIG. 1 and FIG. 5 in the divergent section provides an extra volume to permit easy material insertion in the high-speed motive flow and offering less chance to plugging.

(13) Because of the low pressure at the point of entry 4_4a. only a small volume of air is introduced by the cylindrical inlet section 9. The mixture of expanding motive air and flake ice 11 is accelerated in the divergent section 14 and blown in the circular outlet 6, followed by circular transport tube 16 to a further long distance such as 100 to 120 meters.

(14) Introducing the material (flake ice) in the divergent section provide a larger injection surface area of the divergent section 5 than in the circular throat small diameter 4. Being injected into the divergent section 5 of the venturi, it has a better way of being entrained without too much friction and energy. There are less chances of plugging in introducing the material into the system 11, 13.

(15) Behavior of the motive air flow introduction at the beginning of the divergent section. The tendency of the high-speed fluid jet (around 159.7 m/sec (357 mph) attach the motive jet stream to the adjacent bottom of the divergent section to regain full section area of the divergent tube and exit tube 16 at about 2 meters (6.5 ft) from the throat of this venturi. This caused mainly by the gap suction opening FIG. 1 11 at plane X-X to create an asymmetric downward flow. Note this situation will exist by proper adjusting the converging section angle in order not to amplify the asymmetric effect jet attaching to the bottom part.

(16) The pressure that has dropped and fluid velocity increased as the fluid flows through the contraction 3 is restored after the throat cylindrical section 4_4a to the preconstruction pressure by a gradual dilation in the divergent section 5 of angle less than 15?.

(17) The present invention is in the Lean phase pneumatic conveying using high volume of air at low pressure<1.5 bar (<22 psi). The fan for the motive air must supply air velocities that are above 25 m/sec and better around 30 msec for 1:1 ratio. For a safety margin a velocity near 30 m/sec is good to avoid saltation.

(18) The high velocity found at the point of flake ice insertion 11,13 may provide a degradation of flake ice but not a critical concern.

(19) The construction specifications limits of this invention venturi are as follow: a. Related to Basic Diameter (FIG. 1 and FIG. 2) D=152.4 mm b. Contraction ratio (y) (FIG. 1 4) 0.5<y>0.35 ex: y=0.4 c. Throat ratio (m) 0.1>m<1.0 ex: m=0.1639 d. Contraction angle (?) 15?>?<30? ex: ?=20? e. Diffusion angle (?) 2o>?<15? ex: ?=4? f. Flow ratio (q)=+/?0.8697 of P1/P2 g. Diameter of Flake Ice Inlet (d)=0.164>d<0.409 ex: d=0.266 h. Frustro Conical Angle (c)=55?>c<75? ex: c=60?

(20) This venturi invention could be built proportionally in standard tube sizes of D 1 & 6 of 100 mm (4 in) and 150 mm; 160 mm (6.3 in) 200 mm (8 in) etc. depending on material load and distance needed to convey.

(21) Disengagement into a Cyclone Separator

(22) a) The air stream containing material (air-flake ice) from the conveying pipe A FIG. 6 & FIG. 1 enters the cyclone separator B at tangential angle and is spun rapidly, creating a circular flow that imparts centrifugal force to the particles which strike the wall of the cyclone and fall through a bottom to be discharged into a second venturi C FIG. 1 to redirect the flake ice into a conveying pipe F to another point. b) The disengagement of the gas stream from the flake ice of the first unit FIG. 6 D, can be as an emission to the ambient air or exhaust it in the intake of the secondary motive air blower FIG. 6 E of the secondary gravity venturi FIG. 1 & FIG. 6 C for an extra length of piping. A separate power supply for the motive air blower shall be use. c) Cyclone shall be paired with the venturi capacity. See FIG. 6 & FIG. 7 Venturi Cyclone Body Diameter (I)=610 mm (24 in) Diameter Gas Exit (II)=0.377?I=225 mm (8.9 in) Diameter Inlet Pipe (III)=0.25?I=152.5 mm (6 in) Diameter of Flake Ice Exit (IV)=0.34?I=204 mm (8 in) Height of Cyclone (V)=1.31?I=790 mm (31 in) d) To improve the separation of the flake ice from the motive air, the diameter of the flake ice exit from the cyclone may have to be adjusted to obtain the maximum efficiency. The Diameter of the Flake Ice inlet FIG. 5 & FIG. 6 9 and the Frustro-Conical angle FIG. 5 & FIG. 6 10 for the secondary Venturi can easily be adjusted for the need. The same could apply for the primary venturi for space concern. e) This method shall be of less cost than providing a flake ice production plant at distance.