JPH07163912A - Nozzle - Google Patents

Abstract

PURPOSE: To give a prescribed annular orifice to a stream of water and also to release particles that have been filtered to eliminate the problem of clogging by elevating and lowering a movable disc caught in a spacer ring between a flanged joint and a ring with the inflow and cutoff of water. CONSTITUTION: A nozzle is provided with flanged joint 1 holding a spacer ring 2 and a ring 3 restricting a flow channel. Also a spacer 4 supports a diffuser disc 5 to cause recirculated water to radially flow out. Furthermore, a movable disc 6 is caught in the spacer ring 2 between the flanged joint 1 and the ring 3. By the way, the movable disc 6 has plural steps or folds 7 to secure an annular clearance when it rests on a fiat surface. Then, the nozzle is fitted to an inlet joint below. Therefore, the movable disc 6 rises when water enters the nozzle to give a prescribed annular orifice to a stream of water. On the other hand, it falls when a stream of water is cut off to release particles that have been filtered.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a nozzle for producing a gas microbubble-saturated stream of liquid.

[0002]

2. Description of the Related Art Dissolved air flotatio
n) is a method that relies on the concentration of microbubbles in the range of about 100 microns or less from a supersaturated water source. In most instances, the recirculated or bypassed flow will be saturated with elevated pressure air or any other suitable gas and then
Ejected through a suitable nozzle or orifice, whereupon the microbubbles form as a milky emulsion. The bubbles become attached to solid particles in suspension, carrying these particles as scum to the surface,
The scum may then be removed.

The orifice design has a major effect on the efficiency of the method in two or three respects. First, the turbulent flow and, in particular, the rate at which the pressure is released affects the size of the bubbles, and rapid release favors smaller bubbles.
Second, the orifice and the surrounding assembly must allow for rapid mixing of the recirculation flow into the main flow, while at the same time the coalescence of smaller microbubbles to form larger bubbles is: It must be avoided as large bubbles can interfere with the floating scum. Third, in one form of dissolved air flotation, the recirculated stream is mixed with the flocculated water after addition of the flocculant. In this case, it is necessary to avoid high velocity jets that break the flocs and reduce capture efficiency.

Various devices have been used for this purpose,
Many are based on orifices with a diameter of a few millimeters where the oncoming jet impinges on a target disc or plate.
The advancing jet is allowed to diffuse within the stub tube to reduce velocity before encountering the main flow. Other proposals use a globe valve in which the pressure is reduced via metal seats and discs and an annular slot, and finally a simple needle valve is also used.

At a given pressure, the time it takes for the pressure to be dissipated (in microseconds) is a function of the size of the orifice or annulus, since the angle of the diffusive flow depends on the diameter. Thus, small orifices or rings have been found to provide more rapid reduction and finer bubbles, but the orifices are more prone to blockage. Needle valve systems tend to require opening and resetting to remove the obstruction.

[0006]

SUMMARY OF THE INVENTION The present invention includes a nozzle assembly shaped to provide a narrow restriction to the exiting flow but to allow the device to relieve a blockage by simply interrupting and reopening the flow.

According to the invention, a chamber having an inlet for the liquid and a flow channel connecting the inlet to the outlet for the outflow of the liquid are provided, from the liquid stream supersaturated with gas to the liquid A nozzle is provided which produces a saturated flow of gas microbubbles, the nozzle forming a restriction on the flow channel so that, in use, the flow of gas supersaturated liquid may pass through the restriction. Further comprising a mobile device arranged to move between a first position in which the mobile device cooperates with the body of the nozzle to generate a microbubble and a second position in which the flow channel is unrestricted. The device is arranged to be biased toward the second position but driven toward the first position by the force of the liquid flow past the nozzle.

In the nozzle of the present invention, when the gas supersaturated liquid flow passes through the nozzle, the movable device forms a restriction on the liquid flow, resulting in the formation of a supersaturated liquid flow with gaseous microbubbles. Is driven to the first position.
However, when the fluid flow is interrupted, the bias is
The mobile is returned to the second position, thus allowing any particles filtered by the restriction to release themselves. In this way, the nozzle of the present invention overcomes the blockage problems associated with prior art nozzles.

In one embodiment of the invention, the movable device is arranged to cooperate with the body of the nozzle in the second position to form a narrow annular slot or orifice,
Therefore, in use, the flow of liquid axially through the nozzle is directed radially inward by the slot or orifice.

In a preferred nozzle of this type, the chamber of the nozzle has a flange directed inwardly at its outlet end and the mobile device cooperates in a first position to form an annular slot or orifice. A disc suitably arranged and arranged for axial movement between the flange and the inlet end of the chamber, e.g.
It may have at its edges three or more axial projections, the disk being such that the projections are oriented towards the flange and between the axial projection of the disk and the flange in the first position. Incorporated into the nozzle such that the cooperation of the two results in the formation of a plurality of annular slots. Typically, the mobile device is biased towards the second position by gravity or a spring.

In another embodiment of the invention, the nozzle comprises a second
Coacting with the outlet to redirect the flow radially outward from the nozzle after it has passed through the restriction in the flow channel formed by the cooperation of the body of the nozzle and the movable device in the position. Additionally arranged. The present invention can be better understood by consideration of the following examples with reference to the accompanying drawings.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the nozzle shown in FIGS. 1 and 2, the body portion of the orifice is a flanged joint 1 for holding a spacer ring 2.
And another ring 3 forming one side of the annulus which constitutes the desired restriction on the flow channel of the nozzle. Spacer 4 is a diffuser disc
5, which ensures that the recirculated water is able to flow radially between the ring 3 and the disc 5. 4 and 5, the spacer 4 and the diffuser disc 5 are omitted.

The movable disc 6 is captured in the ring 2 between the flange 1 and the ring 3. The disc has at least three steps (offsets) or folds (crimps) 7,
Therefore, when resting on a flat surface, the desired annular gap is provided. When assembled, the step projects towards the ring 3.

The assembly is usually mounted in the lower inlet fitting 8. Thus, when water enters, the disc 6 rises, giving the flow a preset annular orifice. When the flow is interrupted, the disc falls and allows any particles filtered by the annulus to release themselves.

In contrast to the other embodiments, the weak spring is a disc 6
It may be inserted between the diffuser disk 5 and the diffuser disk 5. The volume and time delay in the assembly downstream of the annulus are very small and can be further reduced by suitable choice of size and shape, eg the disc 5 may be saucer shaped. Also,
The radial flow from the discharge aids in mixing with the main flow, which is often up or down in many designs where air is introduced.

For some applications, the disc 5 and associated spacer 4 may not be necessary (as shown in FIGS. 4 and 5). These are supplementary to the main purpose of the invention. As an alternative to the disc 5, the disc 6 is
It may be contoured or domed to direct the emerging flow axially or even outwardly.

In the nozzle of FIG. 3, the movable disc 6 is biased towards the open position by a spring 11 mounted centrally to the diffuser disc 5. A ring 8 protruding from the surface of the disc 5 surrounds the spring 11. The movable disc 6 also has a ring 9 projecting from its surface towards the diffuser disc 5, the diameter of the ring 9 being larger than the diameter of the corresponding ring 8 on the diffuser disc 5. When water is admitted, the movable disc 6 is pushed upwards until the free ends of each of the protruding rings 8, 9 come into contact with the respective opposite faces of the discs 6, 5. In this working position, 360
A single annular slot of ° is provided for the water flow. When the flow is interrupted, the disc is returned to the open position by the biasing of the spring 11. Recessed stub 10 at the entrance
Prevents the movable disc 6 from falling too far.

[Brief description of drawings]

FIG. 1 is a side cross-sectional view of a nozzle according to one aspect of the present invention.

2 is a cross-sectional plan view of the nozzle of FIG.

FIG. 3 is a side sectional view of an alternative nozzle according to the present invention.

FIG. 4 is a side sectional view of a nozzle that simplifies the embodiment of FIG.

5 is a plan view of the nozzle of FIG.

[Explanation of symbols]

 3 ring 5 diffuser disk 6 movable disk 7 steps (folds) 11 spring

Claims (7)

[Claims] 1. A chamber having an inlet for liquid,
A flow channel connecting the inlet to an outlet for the outflow of liquid, forming a restriction on the flow channel in a nozzle that produces a gas microbubble saturated flow of liquid from a gas supersaturated liquid flow, and In use, the mobile device cooperates with the body of the nozzle so that the passage of a stream of liquid supersaturated with gas through the restriction thus formed causes gas microbubbles in the liquid. Further comprising a movable device arranged to move between a operative first position and a second position in which the flow channel is unrestricted, the movable device being biased towards the second position. A nozzle that is arranged to be driven towards the first position by the force of the liquid flow passing through the nozzle. 2. A nozzle according to claim 1, wherein a narrow annular slot or orifice is formed so that, in use, the flow of liquid axially through said nozzle is directed radially inward by said slot or orifice. A nozzle in which the movable device is arranged to cooperate with the body of the nozzle in the second position so as to be oriented. 3. A nozzle according to claim 2, wherein the chamber of the nozzle has a flange directed inwardly at its outlet end, the movable device forming the annular slot or orifice. A nozzle, which is a suitably arranged disc arranged to effect axial movement between the cooperating flange and the inlet end of the chamber in the first position. 4. The nozzle according to claim 3, wherein said disc has three or more axial protrusions on its edge, said protrusions being oriented towards said flange. A nozzle in which the disc is incorporated into the nozzle such that cooperation between the axial projection of the disc and the flange in one position results in the formation of a plurality of annular slots. 5. The nozzle according to any one of claims 1 to 4, wherein the movable device is urged toward the second position by gravity. 6. The nozzle according to any one of claims 1 to 4, wherein the movable device is biased by a spring toward the second position. 7. A nozzle according to any one of claims 1 to 6, wherein the flow channel is formed by the cooperation of the movable device in the second position and the body of the nozzle. Further comprising a device arranged to cooperate with the outlet to redirect the flow radially outward from the nozzle after the flow of liquid has passed the restriction.