Device for gassing liquids

A device for gassing liquids, in particular for aerating sewage and the like, includes a lower housing element, which has a substantially round opening area and a gas inlet port, a disc-shaped upper housing element, corresponding to the opening area, for covering the opening area, the upper housing element having an upper side facing away from the lower housing element, a number of gas through-openings provided in the vicinity of a peripheral edge of the upper housing element, passing through the upper side, and a perforated gassing membrane, covering over the upper side of the upper housing element.

RELATED APPLICATIONS

The present application is National Phase of International Application No. PCT/EP2011/059290 filed Jun. 6, 2011, and claims priority from German Application No. 10 2010 029 754.2, filed Jun. 7, 2010.

The invention relates to a device for gassing liquids, in particular for aerating sewage and the like.

EP 0 549 518 A1 describes a device for fine-bubble gassing of a liquid. Here, a support plate comprises at least one gas outlet opening. A gassing membrane with a fine perforation is tightly connected in the edge region with the support plate. Furthermore, an opening of the gas outlet opening is provided with a one-way membrane valve which prevents liquid from penetrating into the gas outlet opening. For gassing a liquid, for example, air is pressed through the gas outlet opening and between the support plate and the gassing membrane. As a result, the gassing membrane is lifted from the support plate and forms a convex surface toward the outside. The air passes through the perforation and forms fine air bubbles in the liquid to be gassed. —If a high water pressure of, for example, 4 to 8 meter water column acts on said known device, the gassing membrane is lifted from the support plate only in the region of the gas outlet opening located therebelow. Gas outlet takes place only in this limited region. The effectiveness of the known device is greatly limited in particular in the case of high water pressure.

From DE 94 15 775 U1, another gassing device is known. Here, two radial slots are provided as gas outlet openings in a plate-like support structure. A gassing membrane has no perforation in the region above the gas outlet openings. —This increases the effectiveness of the gassing device in the case of high water pressure. Nevertheless, here too, the regions of the gassing membrane located remote from the gas outlet opening are pressed by the water pressure against the support structure. Disadvantageously, no gas passes in these regions through the perforation of the gassing membrane and into the liquid to be gassed.

It is an object of the invention to eliminate the disadvantages according to the prior art. In particular, a device is to be proposed which enables effective gassing of a liquid even at high liquid pressure. According to another object of the invention, the device shall be as robust and reliable as possible.

This object is achieved by the features of the claim1. Expedient embodiments of the invention derive from the features of the claims2to13.

In accordance with the invention, a device for gassing liquids, in particular for aerating sewage and the like, is proposed,

comprising a lower housing element which has a substantially round opening area and a gas inlet port,

a disk-shaped upper housing element, which corresponds to the opening area, for covering the opening area, wherein the upper housing element has an upper side facing away from the lower housing element, and wherein a plurality of gas through-openings is provided in the vicinity of a peripheral edge of the upper housing element, said gas through-openings passing through the upper side, and

a perforated gassing membrane covering the upper side of the upper housing element.

The upper housing element is substantially formed from a disc-shaped carrier plate, the upper side of which is covered by the perforated gassing membrane. The perforated gassing membrane expediently engages around a peripheral edge of the carrier plate. By providing the gas through-openings in the vicinity of the peripheral edge, it is ensured even at high water pressure that the gassing membrane completely lifts off from the upper side of the carrier plate, and gas passes through the perforations of the gassing membrane. Furthermore, the proposed device has the advantage that already at a relatively low air pressure, air bubbles escape through the gassing membrane. With regard to the quantity of air to be used for gassing, the device can be controlled within a wide range. In a lower control range, the device can already be operated with a small quantity of air.

The term “in the vicinity of the peripheral edge of the upper housing element” is to be understood as an annular area on the upper side which extends from the peripheral edge up to approximately the 0.5-fold, preferably the 0.7-fold, of a radius of the upper housing element. Advantageously, the gas through-openings can be formed as slots which are arranged at the same radial distance from a center point of the upper housing element and extend in sections along an imaginary circle which lies inside the annular area.

According to an advantageous embodiment of the invention, the lower housing element has a bottom which, at least in sections, is configured in a funnel-like manner and on which a connecting piece shaped in the manner of a fillet is molded for positively attaching the lower housing element to a gas supply line. Expediently, the connecting piece is configured in the manner of a semi-cylindrical chute, at the two edges of which outwardly projecting webs can be formed. Further, a counter piece corresponding to the connecting piece can be provided which has substantially the shape of a chute, at the edges of which opposing groove-like recesses are formed. This enables to substantially positively attach the connecting piece to a gas supply line and to interlock the same with the counter piece. For establishing a nonpositive connection, for example, said webs and the groove-like recesses corresponding thereto can be arranged obliquely so that with increasing insertion depth of the webs into the groove-like recesses, an increasing elastic force acts which forces the connecting piece and the counter piece against the gas supply line.

The bottom can comprise a curved section with a curvature that corresponds to the fillet and protrudes toward the opening area. Expediently, the gas inlet port passes centrally through the bottom. Furthermore, the gas inlet port expediently passes through the connecting piece. Thus, by attaching the lower housing element, the gas inlet port can be immediately connected to a gas supply opening in the gas supply line. This simplifies assembling the device according to the invention on the gas supply line.

According to another embodiment of the invention, a gas inlet port opening facing the housing interior of the lower housing element is provided with a one-way valve, preferably a one-way membrane valve. In particular, a one-way membrane valve can be produced in a simple and cost-effective manner. For example, in the case of damage to the gassing membrane, providing a one-way valve prevents liquid from penetrating into the gas inlet port.

According to a further embodiment, it is provided that a cylindrical support structure extends from a lower side of the upper housing element which lower side opposes the upper side. The cylindrical support structure, which is advantageously attached centrally on the lower side, advantageously comprises a plurality of apertures which enable gas to penetrate into the housing interior. Expediently, the apertures are configured in the form of axially extending slots.

From the cylindrical support structure, webs or ribs can extend radially toward the peripheral edge. Such ribs which, expediently, are molded on the lower side of the support plate, increase stability of the device. In particular, undesired deformation of the carrier plate due to the influence of high water pressure is avoided.

Between two adjacent ribs, in each case one gas outlet opening can be provided. Expediently, the gas outlet opening is slot-shaped and extends in the carrier plate adjacent to the peripheral edge from a rib up to the next adjacent rib.

According to a further particularly advantageous embodiment of the invention, the ribs are configured such that they are positively supported in sections on the curved section when the upper housing element is attached on the lower housing element. Thus, the stability of the carrier plate against the action of high water pressure can be further improved.

According to a further particularly advantageous embodiment of the invention, the ribs are configured such that when the upper housing element is attached on the lower housing element, they can be positively supported on the curved section in two directions perpendicular to each other. This means, a lower edge of the ribs is configured in such a manner that the upper housing element can be positively attached in two assembly positions onto the lower housing element, in particular onto the curved section of the bottom. This further facilitates assembling the device.

According to a further embodiment, a threaded ring engaging over the edge of the upper housing element is provided for fastening the upper housing element to the lower housing element. With the proposed threaded ring, the upper housing element is forced against the lower housing element. The proposed connection of the housing elements by means of the threaded ring is detachable. Accordingly, for example, a defective gassing membrane can be replaced.

In theFIGS. 1 to 3, a lower housing element1advantageously made of injection-molded plastic has a cylindrical first peripheral wall2with an external thread3formed thereon. A funnel-shaped bottom section4, which is penetrated by a curved bottom section5, extends from the first peripheral wall2. The curved bottom section5is integral part of a connecting piece6which is molded onto the bottom and is configured in the manner of a half-cylinder.

As is in particular shown inFIG. 2, the connecting piece6has two outwardly extending webs7which run obliquely with regard to an axis of the connecting piece6. A counter piece, designated with the reference number8, is configured in the manner of an expanding half-cylinder and has a groove-like recess9on both of its edges. The groove-like recess9is formed so as to correspond to the webs7so that the counter piece8can be connected to the connecting piece6by sliding it thereon.

An upper housing element10, advantageously made of injection molded plastic, is constructed in the manner of a disc and has a cylindrical second peripheral wall11. An outer diameter of the second peripheral wall11is smaller than an inner diameter of the first peripheral wall2so that the upper housing element10can be inserted into the lower housing element1. An upper side O of the upper housing element10is formed to be substantially flat. Adjacent to the second peripheral wall11, a carrier disc12forming the upper side O has slot-like gas through-openings13.

As is in particular shown in theFIGS. 4 and 5, reinforcement webs or ribs14extend from the second peripheral wall11in the radial direction on a lower side U of the carrier disc12.

A height of the ribs14molded on the carrier disc12increases in sections from a peripheral edge, formed by the second peripheral wall11, of the upper housing element10toward the center of the latter. The center of the lower side U is surrounded by a cylindrical support structure15which extends from the carrier disc12. The ribs14adjoin the cylindrical support structure15. The cylindrical support structure15has a multiplicity of axial slots16which extend between the ribs14up into the vicinity of the carrier disc12.

At least a portion of the ribs14has in each case a support edge17in the vicinity of the cylindrical support structure15. Height and inclination of the support edge17are adapted in such a manner that in the assembled state, at least a portion of the ribs14is supported on the curved bottom section5. In a similar manner, upper edges18, also shaped in the form of circular arc sections, of the cylindrical support structure15are also formed such that, in the assembled state, they are positively supported on the curved bottom section5.

Although not shown in the figures, it is also possible that the support edges17of the ribs14are configured in such a manner that they can be supported in two installation positions, for example differing by 90°, in each case on the curved bottom section5.

Reference number19designates a gassing membrane which is made, for example, from silicone rubber and which is configured so as to correspond to the upper side O and the second peripheral wall11. A circumferential edge section of the gassing membrane19embraces in the assembled state the second peripheral wall11in such a manner that the upper housing element10inserted into the lower housing element1is supported via the edge section of the gassing membrane19on a support web20molded onto the lower housing element1. Through this, a gas-tight sealing of a housing formed by the upper10and the lower housing element1is achieved.

For fastening the upper housing element10together with the gassing membrane19attached thereto, a threaded ring21is provided, the inner wall of which has an internal thread22that corresponds to the external thread3. An intermediate ring23applies a clamping force exerted by the threaded ring21uniformly to the gassing membrane19and forms at the same time a sliding surface when tightening the threaded ring21.

The curved bottom section5of the lower housing element1is penetrated by a gas inlet port24, wherein on the inlet port's one end facing the housing interior, a one-way membrane25having a membrane plate26and a perforated valve membrane27attached thereto is provided.

The function of the device is the following:

For assembling on a gas supply line (not shown in the figures) provided with a gas supply opening, the pre-assembled device with the connecting piece6is placed onto the gas supply line in such a manner that the gas inlet port24penetrates through the gas supply opening (not shown here). Subsequently, the counter piece8is attached onto the connecting piece6and the device is thereby clampingly fastened to the gas supply line.

The air fed under pressure through the gas supply line flows through the gas inlet port24and the one-way membrane valve25and arrives in the cylindrical support structure15, and from there through the axial slots16in a gas supply chamber formed between the ribs14. From there, the fed air is pressed through the gas through-openings13and against the perforated gassing membrane19. The air penetrates the perforations provided in the gassing membrane19and penetrates in the form of fine bubbles into a liquid surrounding the device.

By pressing the air through the gas through-openings13arranged radially outward in the carrier plate12and against the gassing membrane19, the gassing membrane19inflates starting from the peripheral edge over the full area. The entire area of the gassing membrane19is utilized for generating gas bubbles.

A liquid pressure acting during interrupted gas supply on the upper housing element10is applied via the cylindrical support structure15and the ribs14with the support edges17provided thereon in particular against the curved section5of the bottom of the lower housing element1.

REFERENCE LIST