FR2878618A1 - Gas flow measurement device in aeration tank comprises gas trap, evacuator allows gas to the trap level, sealing gas duct with diffuser, which connecting trap to the evacuator and flow measurement placed at the level of gas pipeline - Google Patents

Abstract

The sealing contains a joint having a section, which allowing its support on the diffuser type membrane (4). The trap (5) has truncated form to reduce the concentrate of duct in the flow meter. The wide end of the trap has higher dimensions than the gas diffuser zone. Ultrasonic flow meter of data transmission is measured by telegraphic/radioelectrical. Gripping at the enclosure level, which allows the handling of the unit.

Description

2878618 1

  DEVICE FOR MEASURING THE FLOW OF GAS

  The present invention relates to a device for measuring the flow of gas from an underwater diffuser.

  It will mainly find its application in carrying out functional tests of diffusers arranged in urban or industrial ventilation basins.

  However, although more particularly intended for such applications, the device can also be used in any other application in which the gas diffuser is located under water.

  Typically, sewage treatment and purification works comprise a number of basins in which successive treatments of wastewater are carried out.

  Some of these basins are equipped with air diffusers or gas diffusing into the pool of microbubbles and aimed to provide aeration and oxygenation of wastewater.

  These tanks are equipped with a large number of diffusers which are subject to fouling due to a build-up of sludge at the gas outlet or diffuser, and in particular at their membrane for membrane-type diffusers.

  In this type of basins, the circulation of the wastewater is very random and inhomogeneous so that it is not possible to predict in advance the level of fouling of a diffuser and also so that the diffusers have at least during the same cycle fouling levels can be very different.

  To allow a good functioning of the basin, it is necessary to regularly test all the diffusers one by one to evaluate their level of fouling.

  European legislation requires limiting the periods of unavailability of treatment facilities and therefore the maintenance and verification of the 2878618 2 devices contained in the basins must be performed while they are not drained.

  Currently, the test of the diffusers is carried out by a diver who has to evaluate manually and one by one the fouling of the various diffusers.

  Specifically, the diver passes his hand over each diffuser and depending on the air flow to him assesses the fouling rate of the corresponding diffuser.

  It is easy to understand that this method is not reliable or accurate and that it also requires a significant dive time in particularly difficult conditions given the turbulence, sometimes high temperatures, the zero visibility prevailing in the basins.

  The present invention aims to overcome the aforementioned drawbacks and to provide a device for measuring the gas flow of an underwater diffuser for a precise evaluation of the fouling rate of each diffuser.

  Another object of the present invention is to provide a reliable device that can be used in extreme conditions and in particular in chemical, toxic and explosive environments.

  Another object of the present invention is to provide a device whose structure and dimensions allow easy handling by the technician.

  The invention thus relates to a device for measuring the flow of gas from an underwater diffuser, in particular located in a ventilation tank.

  According to the invention, it comprises: a gas collector adapted to cover the gas outlets of a diffuser; an evacuator for returning the gas substantially at its collection; a gas pipe connecting the collector to the evacuator, - flow measurement means disposed at the gas line.

  Other advantages and characteristics of the invention will appear more clearly on reading the following description of a preferred embodiment in which the description is given by way of non-limiting example and with reference to the figure which shows in schematic sectional view a preferred embodiment of the device according to the invention.

  Referring to the figure, there is shown a device 1 for measuring the gas flow of an underwater diffuser 2.

  These diffusers 2 are supplied with gas and, for example, air by a distribution rod 3, itself connected to an air supply device not shown in the accompanying drawing.

  It is a set / feeding device / rod / diffuser conventionally used in the purification tanks and well known to those skilled in the art.

  The diffusers 2 shown in the figure have on their upper faces a membrane 4 permeable to gas and impermeable to liquid.

  This membrane 4 is generally in the form of a disc.

  It is important to note at this level that other geometries are known to achieve a diffuser 2 and in particular the latter may be constituted by a tube on the surface of which are made perforations or mounted porous membranes of tubular form.

  The device 1 may be adapted geometrically so as to be able to measure the flow of diffusers 2 of various geometrical shapes and in particular of tubular type diffusers as mentioned above.

  The device 1 comprises a gas collector 5 capable of covering the gas outlets 20 of the diffuser 2.

  In the case shown in the figure of a membrane-type diffuser, the collector 5 covers the entire membrane surface, the gas diffusing indeed through the entire surface of the membrane 4.

  Said device 1 further comprises an evacuator 6, the latter having the function of restoring the gas substantially at its capture.

  This characteristic is particularly interesting since it allows in particular to have a balance between the pressure of the captured gas and the pressure of the returned gas favoring a precise measurement of the gas flow.

  The device 1 also comprises a gas pipe 7 connecting the collector 5 to the evacuator 6.

  The measurement of the gas flow is carried out by flow measurement means 8 arranged at the level of said gas pipe 7.

  In order to achieve an accurate measurement of the gas flow, it is expected that the collector 5 comprises sealing means 9 with the diffusion zone of the diffuser 2.

  In the case of a diffuser 2 of the membrane type, it may advantageously be provided that these sealing means 9 are made by an inner seal 10 disposed on the inner wall 11 of the collector 5.

  This seal 10 has a section allowing its support on the peripheral edge of the membrane 4 of the diffuser 2.

  This seal 10 is in contact during the displacement of the device 1 with the wastewater, that is to say a relatively aggressive chemical medium; it will be made of a specific material.

  As indicated above, the gas manifold 5 has a shape for covering the gas outlets of the diffuser 2.

  It has for this purpose a first section corresponding to the diffusion zone of the diffuser 2 and a reduced section in the direction of the gas pipe 7 so as to concentrate the gases.

  The subjection between the collector 5 and the pipe 7 can be achieved by any means known to those skilled in the art and in particular by bolting or crimping.

  In order to facilitate the contact and the positioning of the collector 5 at the level of the diffuser 2, provision is made for the section of the enlarged end of said collector 5 to have dimensions slightly greater than the zone of diffusion of the gas.

  Of course, especially in view of the fabrications, the collector 5 25 will have a simple geometric shape.

  In particular, the collector 5 may have a frustoconical shape that will be particularly suitable for membrane-type diffusers.

  However, again, many other forms are conceivable for the skilled person.

  The gas entering said manifold 5 is then directed to the gas line 7 at which the measurement of the gas flow takes place.

  This measurement is performed by flow measurement means 8; it may especially be a mechanical flow meter and for example of the fin type, piston or drum.

  It will also be possible to envisage other types of flowmeter known to those skilled in the art, and in particular an optical and preferably an ultrasonic flow meter.

  At this level, it is important to underline that the data may possibly be transmitted directly in real time to the outside and according to an advantageous variant, the device 1 comprises means 18 for transmitting the data measured by the flowmeter, and in particular, means wired or radio transmission.

  According to another variant embodiment of the invention, all the data measured by the flow meter may also be stored in an EEPROM type memory integrated in the device 1, access to this memory can be made once the device 1 out of water.

  The path of the gas follows that of the pipe 7 and then returns to the level of the lower part of the device 1.

  To this end, it can be provided, as shown in the figure, that the pipe 7 is constituted by an inner tube 12 disposed in the upper part 13 of the enclosure 16, the tube and the inside of the enclosure being in communication at the upper end 14 of the tube 12, the gas flowing in a first time in the tube 12 and in the space defined between the tube 12 and the inner wall of the upper portion 13 of the enclosure 16.

  The outlet of the pipe 7 is subjected to an evacuator 6.

  According to the advantageous embodiment of the figure, the evacuator 6 is formed by the space between a wall 15 at least partially covering the collector 5 and the wall 11 of the collector 5 allowing a return of the gas flowing in said space, which is in contact with the outside.

  In the embodiment of the figure, the walls 15 and 11 have a similar geometric shape.

  All of the aforementioned elements of the device is housed in an enclosure 16 constituted by the wall of the evacuator 6 and a part of the pipe 7.

  The materials used for the realization of this chamber 16 will be adapted to withstand significant chemical attack.

  In order to facilitate the manipulation of the device by the technician, it is also provided that this device 1 comprises gripping means 17.

  These gripping means 17 may consist of one or more handles disposed at the level of the enclosure 16.

  The enclosure 16 has rounded shapes to limit the salient angles that could injure the technician or tear his suit.

  The device 1 as aforesaid thus allows to facilitate the evaluation of the fouling of the diffusers 2; the evaluation operations are therefore considerably more precise than the manual operations carried out so far.

  Of course, other embodiments within the reach of ordinary skill in the art could have been envisaged without departing from the scope of the invention defined

by the claims below.

Claims (13)

  1. Device for measuring the flow of gas from an underwater diffuser, especially located in a ventilation tank, CHARACTERIZED in that it comprises: a gas collector (5) capable of covering the gas outlets of a diffuser, - an evacuator (6) for restoring the gas substantially at its collection, - a gas pipe (7) connecting the collector (5) to the evacuator (6), 10 - measuring means (8) ) of the flow arranged at the level of the gas line (7).   2. Device according to claim 1, wherein the collector (5) comprises sealing means (9) with the diffusion zone of the diffuser (2).   3. Device according to claim 2, wherein the sealing means (9) comprise an inner seal (10) having a section allowing its support on the peripheral edge of the membrane (4) of a diffuser (2) of the type membrane.   4. Device according to any one of claims 1 to 3, wherein the gas manifold (5) has a reduced section towards the pipe (7) so as to concentrate the gases towards the flowmeter.   5. Device according to claim 4, wherein the section of the enlarged end of the collector (5) has dimensions slightly greater than the gas diffusion zone of the diffuser (2).   6. Device according to claim 4 or 5, wherein the collector (5) has a frustoconical shape.   7. Device according to any one of claims 1 to 6, wherein the evacuator (6) is formed by the space between a wall (15) at least partially covering the collector (5) and the wall (11). collector (5) for a return of the gas flowing in said space in contact with the outside.   8. Device according to any one of claims 1 to 7, wherein the evacuator (5) and the gas pipe (7) constitute the enclosure (16) of the device.   9. Device according to any one of claims 1 to 8, wherein the measuring means (8) consist of a flow meter.   10. Device according to claim 9, wherein the flow meter is ultrasonic.   11. Device according to any one of claims 1 to 10, comprising data transmission means measured by the measuring means (8).   12. Device according to claim 11, wherein the data transmission means are wired or radio.   13. Device according to any one of claims 1 to 12, comprising gripping means (17) at the chamber (16) for handling the assembly.