EP2536476A1

EP2536476A1 - Device for evaporating a processing liquid

Info

Publication number: EP2536476A1
Application number: EP11706168A
Authority: EP
Inventors: Bertrand Gruson
Original assignee: Serac Group SAS
Current assignee: Serac Group SAS
Priority date: 2010-02-19
Filing date: 2011-02-18
Publication date: 2012-12-26
Also published as: FR2956591B1; FR2956591A1; WO2011101159A1; BR112012016987A2; US8741102B2; US20110203914A1

Abstract

The invention relates to a device for evaporating a processing liquid, which comprises a cylindrical housing (1) having an outlet opening (16) leading to the upper end of the housing, the housing being arranged vertically and comprising a heated inner wall (3) as well as liquid sprinklers (9) associated with pressurized-air blowing nozzles (10) for forming a jet of a mixture comprising air and a processing liquid sprayed in a direction tangential to the inner wall of the housing, each liquid sprinkler and the associated blowing nozzle being arranged so that the mixture jet is formed in an upper portion of the housing and oriented downwards.

Description

DEVICE FOR EVAPORATING A LIQUID OF

TREATMENT

The present invention relates to a device for evaporation of a treatment liquid, particularly although not exclusively the extraction of hydrogen peroxide from a solution of hydrogen peroxide.

BACKGROUND OF THE INVENTION

It is known that hydrogen peroxide is used in particular for the sterilization of containers prior to an aseptic filling of the containers. However, hydrogen peroxide is considered as a pollutant and therefore there are specific standards on the allowable residual quantities when the container is intended to contain food products. To meet these standards the containers must be treated with a process gas free of liquid droplets.

It is known to extract hydrogen peroxide from a solution of hydrogen peroxide by causing evaporation of the solution. It is known in particular from US 4,631,173 to spray a solution of hydrogen peroxide in a stream of air and then put the stream obtained in contact with the inner wall of a heated tube. However, for the entire solution to be in the vapor state, it is necessary to provide a tube of great length, which implies a large size of the installation. In addition, the solution deposits solid residues inside the tube which are inaccessible and therefore difficult to eliminate.

It is also known from WO 91/17804 to produce an evaporator comprising a cylindrical chamber having a heated wall in which a liquid mixture is introduced in spray form by means of a nozzle of liquid arranged to introduce the sprayed liquid in cyclonic motion inside the enclosure. However, this evaporator is intended to ensure a distillation of a part of the mixture and its structure does not make it possible to obtain a conversion of the liquid into a purely gaseous flow.

OBJECT OF THE INVENTION

An object of the invention is to provide a device of simple structure for extracting a treatment gas from a treatment liquid reliably both from the point of view of the extraction of the gas without liquid entrainment that from the point of view of the operation of the device.

SUMMARY OF THE INVENTION

With a view to achieving this object, the invention proposes a device for evaporation of a treatment liquid comprising a cylindrical chamber having an outlet opening opening at the upper end of the chamber, the chamber being arranged vertically and having a heated internal wall, and means for introducing the treatment liquid into the chamber in a cyclonic movement in contact with the inner wall of the chamber, wherein the introduction means comprise at least one fluid nozzle associated with a pressurized air blowing nozzle for producing a jet of air mixture and sprayed treatment liquid in a direction tangential to the inner wall of the enclosure, each liquid nozzle and the associated blowing nozzle being arranged so that the mixing jet is formed in an upper part of the enclosure being inclined downwards.

Thus, the mixture cyclically descends to the bottom of the chamber and then also rises in a cyclonic motion in the center of the chamber so that the drops of treatment liquid are subjected to a centrifugal force bringing them back to the hot wall. for a time sufficient for the output stream to be free of any droplets.

According to an advantageous version of the invention the enclosure comprises a flange extending inwardly projecting between the liquid jets and the outlet orifice. This avoids any rise of liquid along the inner wall of the enclosure.

According to another advantageous aspect of the invention the device comprises at least one additional blowing nozzle, which makes it possible to vary at will the amount of treatment product finally included in the flow flowing at the outlet. Preferably an additional blast nozzle is associated with each liquid nozzle and is disposed relative thereto for directing the blast jet downwardly. This prevents droplets being projected upwards at the outlet of the liquid nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will emerge in the light of the following description of a particular non-limiting embodiment of the device according to the invention, with reference to the attached figures among which:

- Figure 1 is a perspective sectional view of the device according to the invention by a vertical axial plane of the enclosure

- Figure 2 is a partial perspective view in section along an axial vertical plane of a liquid nozzle and the associated blowing nozzle

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figures, the device according to the invention comprises a cylindrical enclosure 1 of circular cross section having a concave bottom, here curvilinear. The side wall 2 is formed as a double wall comprising an inner wall 3 and a outer wall 4 delimiting a space 5.

The space 5 is closed at its upper end by an annular ring 8 which also serves to support means for introducing the treatment liquid whose structure will be detailed below.

A circulation of water vapor in the space 5 is carried out by introducing water vapor V via a steam introduction connection connection 6 at the base of the chamber and extracting the vapor V via a connection a steam outlet connection 7 carried by the ring 8 in an offset angular position of the connection connector 6, here in a diametrically opposed position, in order to force the vapor to circulate around the inner wall 3 in the space 5 between the internal wall 3 and the outer wall 4 in a helical motion.

To the ring 8 is associated an annular ring 14 which is removably attached sealingly to the ring 8 by unrepresented fastening means. The ring 14 supports the lid 15 of the enclosure formed of a double wall pierced at its upper part with an outlet orifice 16 in which is mounted in leaktight manner an outlet conduit 17 suitably connected to devices for using the obtained treatment product.

The device further comprises liquid nozzles 9 carried by the ring 8. Each liquid nozzle 9 is formed of a hollow needle having an end 12 extending inside the chamber and pierced with a hole of outlet and an end 16 extending outside the enclosure and suitably connected by a connector 17 to a feed circuit shown for supplying the liquid jets 9 treatment liquid L, here a solution of peroxide d hydrogen.

At each fluid nozzle 9 is associated a blowing nozzle 10 extending coaxially with the nozzle 9 corresponding. The outlet orifice 11 of each nozzle 10 is adjacent to the outlet orifice 12 of the nozzle 9 corresponding, slightly recessed relative thereto. Outside the enclosure, the blast nozzle 10 is connected by a connection 18 to a source of pressurized air for injecting pressurized air A into the blast nozzle. The outlet orifice 11 of the blast nozzle 10 is arranged with respect to the outlet orifice 12 of the nozzle 9 to cause spraying of the liquid coming out of the nozzle 9 and to drive the sprayed liquid in a stream tangential to the inner wall 3 The jets 9 and the associated blowing nozzles 10 are inclined downward by an angle sufficient to cause a downward cyclonic movement of the spray mixture of sprayed liquid droplets and air. In practice, the angle of inclination of the nozzles 9 and the associated blowing nozzles 10 is between 10 ° and 20 °, preferably close to 10 °.

In the preferred embodiment illustrated an additional blow nozzle 19 is associated with each liquid nozzle 9 and is disposed with respect to the liquid nozzle 9 to deflect down the mixture of sprayed liquid and air produced by the nozzle of the nozzle. liquid 9 and the associated blowing nozzle 10. For this purpose each additional blast nozzle 19 is preferably arranged downstream of the corresponding liquid nozzle 9 with reference to the mixing jet and has a slightly greater inclination than the liquid nozzle 9, for example at an angle of 15 ° to 30 °. The additional blow nozzles 19 are fed by a circular duct 20 made by the coincidence of two grooves formed in the flanges 8 and 14. The circular duct 20 is suitably connected by a connector 21 to an external air source A. An annular flange 22 made at the upper part of the flange 8 extends inwardly projecting from the chamber between the liquid jets 9 and the outlet orifice 16 and prevents a rise of liquid along the wall. 3.

During the implementation of the device of the mixture jets that sprayed liquid propagate helically as illustrated by a dash line in Figure 1 in connection with a liquid nozzle 9 and the blowing nozzles 10 and 19 associated. The mixing jet is first propagated downwards while being in contact with the hot wall 3 and then goes up in the central part. The drops of liquid that could possibly remain in the gas flow back to the outlet orifice are subjected to a centrifugal force bringing them into contact with the hot wall 3.

When the mixture reaches the outlet duct 17, this mixture therefore comprises hydrogen peroxide in the form of gas completely free of droplets and this gas can therefore be used satisfactorily for the sterilization of containers for receiving food products.

According to another aspect of the invention the device comprises at its lower part an orifice 23 for introducing and discharging a cleaning liquid associated via a valve 24 to a feed and drain duct of 25. In addition an overflow tube 26 is disposed inside the enclosure and extends axially. The overflow tube 26 has an upper end extending to at least an identical level, and preferably slightly greater than the lower end 12 of the liquid nozzles 9 as can be seen in FIG. 2. At its lower end the overflow tube 26 passes through the bottom of the enclosure and is kept closed by a valve 27 during the operation of the device.

During operation of the evaporator solid residues are deposited on the wall 3 and in the bottom of the enclosure. When cleaning the valves 23 and 27 are opened and an acid cleaning product is introduced through the orifice 23 until the liquid reaches the upper end of the overflow tube 26. The cleaning product thus ensures a dissolution of the solid residues not only on the wall 3 and in the bottom of the enclosure but also on the end 12 of the nozzles 9.

Of course, the invention is not limited to the illustrated embodiment and is capable of alternative embodiments without departing from the scope of the invention as defined by the claims.

In particular, although the device according to the invention was illustrated with additional blowing nozzles 19, which makes it possible to vary at will the hydrogen peroxide content of the gaseous mixture leaving the evaporator, provision can be made for a device comprising only the liquid nozzles 9 and the associated blowing nozzles 10.

Although the invention was illustrated with several liquid nozzles 9, it is possible to produce a device comprising a single liquid nozzle 9 and the associated blowing nozzle 10.

Although in the illustrated embodiment the liquid jets 9 are all arranged at the same level in the chamber, it can provide that arrange and the liquid jets at different levels to ensure an offset of the mixing jets. In this case it will be necessary to provide a cleaning device different from that which has been illustrated in order not to pollute the liquid nozzles and blowing nozzles associated with cleaning product. Although the chamber 1 has been illustrated in the form of a cylinder of circular section having a smooth inner wall, the device according to the invention can also be made with an enclosure having an inner wall having any shape and / or whose internal surface has a non-smooth surface state, for example with splines for causing turbulence within the flow generated by the blowing nozzles 10.

The heating of the enclosure can be achieved by a coil surrounding the enclosure outside thereof.

Although the invention has been described more particularly for an extraction of hydrogen peroxide, the device of the invention can also be used for other treatment liquids.

Although the invention has been described with nozzles extending coaxially with the blowing nozzles, the invention can be realized with nozzles extending perpendicular to the wall and blowing nozzles arranged perpendicular to the end of the nozzles.

Claims

1. A device for evaporation of a treatment liquid comprising a cylindrical chamber (1) having an outlet orifice (16) opening at the upper end of the chamber, the chamber being arranged vertically and having an internal wall ( 3) heated, and means for introducing the treatment liquid into the chamber in a cyclonic movement in contact with the inner wall of the enclosure, characterized in that the introduction means comprise at least one liquid nozzle (9 ) associated with a pressurized air blast nozzle (10) for producing a jet of air mixture and sprayed process liquid in a direction tangential to the inner wall of the enclosure, each nozzle of liquid and the nozzle blowing device being arranged so that the mixing jet is formed in an upper part of the enclosure being inclined downwards.

2. Device according to claim 1 characterized in that the cylindrical chamber (1) has a concave bottom.

3. Device according to claim 1 characterized in that it comprises a flange (22) projecting projecting inwardly of the chamber between said at least one liquid nozzle (9) and the outlet orifice ( 16).

4. Device according to claim 1 characterized in that it further comprises at least one additional blowing nozzle (19).

5. Device according to claim 4 characterized in that said at least one additional blowing nozzle (19) is disposed relative to said at least one liquid nozzle (9) to push the jet of mixing downwards.

6. Device according to claim 5 characterized in that said at least one additional blowing nozzle (19) is disposed downstream of said at least one liquid nozzle with reference to the mixing jet, and that said at least one additional blowing nozzle (19) has a steeper inclination than said at least one liquid nozzle.

7. Device according to claim 6 characterized in that it comprises a plurality of nozzles of the liquid (9) each associated with an air blowing nozzle (10) and an additional blowing nozzle (19).

8. Device according to claim 1 characterized in that it comprises a cleaning duct (23) opening into the bottom of the tank.

9. Device according to claim 8 characterized in that it comprises an overflow duct (26) extending vertically from the bottom of the tank.

10. Device according to claim 9 characterized in that the overflow pipe has an upper end extending to a level at least identical to a lower end (12) of said at least one liquid nozzle (9).