FR2495028A1 - CLEANING ELEMENT AND CLEANING INSTALLATION USING THE SAME - Google Patents

Abstract

1. A cleaning component for an industrial apparatus in which a fluid flows which is capable of provoking calcium deposits and biological deposits, said cleaning component being brought into the fluid in great quantities and acting by mechanical action on the walls of the apparatus, characterized in that it is constituted by an artificial grain (1) made of a mixture of synthetic substances which are capable of withstanding a temperature of up to 150 degrees C, the grain having an average density of between 0,8 and 1,5 relative to the density of the fluid and an average diameter which lies between 40 and 6 000 mu m.

Description

_1- Cleaning element and cleaning installation using

  This element relates to the cleaning of industrial containers or devices in which circulates a fluid capable of leaving biological or mineral deposits. In particular, the invention relates to the cleaning of exchangers, whether they be

  tubular, plate or serpentine.

  Mechanical or chemical cleaning systems are known; some mechanical systems use brushes, when the container to clean allows their introduction. This system has the disadvantage of requiring the shutdown of the device to clean and disassembly and reassembly of some parts. The immobilization of the device, the labor required for cleaning, makes the application of the system, which otherwise, does not apply

  not all devices to clean.

  The system has been improved by using, instead of brushes, foam balls driven by the fluid and describing a closed circuit within the device to be cleaned. These balls wear out quickly; moreover, the system is unusable for cleaning certain types of heat exchangers such as heat exchangers

plate or serpentine.

  The chemical cleaning systems by introducing into the fluid cleaning agents (for example chlorine) have serious drawbacks because of the difficulties posed by the pollution created by the release of these agents or the corrosion of materials. Systems have also been used in which the fluid is loaded with abrasive elements, such as sand or earth

  of diatoms. The use of these abrasives requires the shutdown of

  the exchanger to be cleaned and special provisions

exchangers.

  Moreover, these abrasives have the defect of using the container to be cleaned and accumulate in certain parts of the container where the speed of the fluid is lower, which makes their use

  impossible in some types of exchangers.

  An object of the invention is to provide a cleaning element for use in all types of industrial containers, without risk of accumulation or settling in a portion of the container. Another object of the invention is to provide an element that does not wear too quickly itself and that does not risk to deteriorate by excessive abrasion inside the device to be cleaned. Another object of the invention is to define an installation using the aforementioned cleaning element, for the cleaning of a

  industrial device during the operation of the latter.

  The invention relates to a cleaning element of an industrial device in which circulates a fluid capable of causing mineral and biological deposits, said cleaning element being introduced in large numbers into the fluid and acting by mechanical action on the walls of the fluid. device, characterized in that it consists of an artificial grain of a mixture of synthetic materials capable of withstanding a temperature of up to 150 degrees, the grain having a relative density of between 1.02 and 1.5 and a particle size of between 40

and 3000 microns.

  For the cleaning of tubular pipes of given diameter, the grain has a grain size of between one tenth and

a quarter of said diameter.

  For the cleaning of hard deposits, the grain is responsible for

abrasive particles.

  The invention also relates to an installation for cleaning an industrial device in which a fluid circulates when the device operates, said fluid arriving at the device through an inlet pipe and leaving by an outlet pipe said installation allowing the cleaning the device during its operation and using the elements of the aforementioned type, characterized in that it comprises, in series with the device, a liquid-solid separator and in parallel on the assembly constituted by the device and the separator, a silo for storing cleaning elements, a dosing member for ensuring a determined proportion of elements in the fluid and

a circulation pump.

  The invention is specified in the embodiment examples given below with reference to the accompanying drawings, in which: FIG. 1 is a sectional view of a cleaning element according to

a first embodiment.

  FIG. 2 is a sectional view of a cleaning element according to

variant.

  FIG. 3 is a schematic view of a cleaning installation using the cleaning element of the invention, the operation

  the device to be cleaned is previously stopped.

  FIG. 4 is a schematic view of a cleaning installation using the cleaning element according to the invention and allowing

  to clean the installation without stopping its operation.

  Figure 1 shows, in cross section, a cleaning element 1 according to the invention, which applies to soft fouling. It is presented in substantially spherical form, and its diameter is between 40 and 3000 microns. It can also be

  of any shape for soft fouling.

  To clean cylindrical tubes, a value of the diameter of the element between a

  tenth and a quarter of the internal diameter of the tubings.

  The element is made of a mixture of plastic and various components; the proportions of the various components are chosen so that the relative average density of the element is between 1.02 and 1.5. This density range has a double advantage: the element is of sufficiently low density not to accumulate in the parts of the device where the flow velocity of the fluid is lower; on the other hand, its density

  sufficiently different from that of the working fluid of the

  sitive (usually water when the device is a heat exchanger), to be separated from the fluid by means of separator included in a cleaning system, as will be described

further.

  Materials which can withstand a temperature up to 1500 ° C. are also chosen, and have a hardness greater than that of the soft deposits to be removed, but less than that of the metal.

  constituting the device to be cleaned.

  By way of example, the element is made from polypropylene with a density of about 0.8, mixed with calcium carbonate, of density 2.7 in selected proportions, to ensure the finished element. a relative density within the range indicated above. The elements are obtained by a hot compounding process. When there are hard deposits to remove (precipitates of mineral salts for example), it is preferable to use cleaning elements of the type of that of FIG. 2, which is substantially spherical and which differs from that of FIG. 1 in that it comprises, embedded in its interior, abrasive particles 2, such as powder

corundum or silica.

  The cleaning elements can be used conventionally to clean an installation whose operation is previously stopped. Such an installation is schematically represented in

Figure 3.

  One distinguishes a device to be cleaned 10, which is for example a heat exchange, receiving a cold fluid (water) through an inlet pipe i1 with a pump 12, this fluid exiting

  of the device via an outlet pipe 13.

  Valves 14 and 15 make it possible to isolate the device in order to clean it. The cleaning installation comprises in parallel on the device 10 from the outlet to the inlet thereof a circuit composed successively of a liquid-solid separator 30, a storage silo 40, a dosing apparatus 45 and a cleaning pump 50. A pipe 60 further connects the outlet of the device 10 and the inlet of the pump 50 and allows to circulate

  in derivation when the fluid at the desired concentration of elements.

  All the above organs are framed with shut-off valves.

  A pipe 61 connects via a valve 62 the upper part of the separator to the pipe 60. It allows the liquid to be recycled until the total separation of the elements

fluid.

  Similarly a pipe 63 connects via a valve 64, the top of the storage silo 40 to the pipe 60; it allows concentration of the fluid. A pipe 65, isolated by a valve 66, allows the rejection of biological suspensions from cleaning. A pipe 70, starting from the top of the storage silo 40 allows the fluidization of the elements. This pipe is connected to the base of the silo by a pipe 71 via a

valve 72 and a pump 73.

  Valves 41, 51, 67 and 81 complete the device.

  The operation of the installation is as follows: - in the absence of cleaning the valves 51 and 81 are closed, the valves 14 and 15 are open and the water circulates in the exchanger

under the action of the pump 12. -

  to clean, the pump 12 is stopped, the exchanger is isolated by

  closing valves 14 and 15, and valves 51 and 81 are opened.

  The set of valves and pipes allows the realization of the following three phases: 1. the injection of elements into the liquid at a given concentration; 2. the circulation of the fluid loaded with cleaning elements in the device to be cleaned bypass with the separator and the storage silo; 3. recovery of cleaning elements before delivery

in use of the cleaned device.

  In the first phase, the separator is isolated by closing the valves 31 and 62. The valves 12, 64, 41 and 72 are open; the valve 67 is closed. The concentration of cleaning elements is determined by the fluidization of a part of the elements contained in the storage silo 40. The fluidization is obtained by injecting a small flow of water with the pump 73. Measurement

  the concentration is determined by the metering device 45.

  In the second phase, the valves 31, 62, 64 and 41 are

  closed; the valves 12 and 67 are open.

  The cleaning is effected by circulation of the cleaning element-laden fluid outside the separator 30 and the storage silo 40. The concentration of elements is advantageously from 5 to 15%. Speed

  The flow rate may be between 0.2 and 195 m / s for

  lures of internal diameter & 8 mm, and between 0.8 and 4 m / s for

  tubing with a diameter greater than 8 mm.

  A cleaning time of 15 minutes is sufficient in general if

  is repeated perlodically (for example, every month).

  The third phase is to recover the cleaning elements.

  For this purpose, the valves 12, 64, 41 and 72 are closed and the valves 31,

62, 67 are open.

  The elements are completely cleaned and separated from the water in the separator 30. The waste is discharged via line 65

  and the cleaning elements return to the storage silo 40.

  The plant can then be re-supplied with clean water and the installation cleaned by circulating the water in the separator and

piping 65.

  An installation of the type which has just been described has the disadvantage of forcing the shutdown of the device to be cleaned. It requires the use of a strong cleaning pump 50 capable of circulating the entire flow of the exchanger. It does not allow

  to accurately assess the progress of cleaning.

  The installation shown diagrammatically in FIG. 4.

  on the contrary, allows the cleaning of a device without requiring the cessation of its operation. In addition, it only requires a low flow pump. 11e allows, by periodic tests on the heat exchange coefficient, to carry out phases of

  accurate time cleaning done correctly.

  The elements common to Figures 3 and 4 have received the same reference number. During cleaning, the valve 15 being closed, the separator 30 is crossed this time by the total flow Q of

  the exchanger increased the flow q of the cleaning installation.

  The synthetic cleaning elements, introduced into the cleaning circuit consisting of the separator 30, the silo 40, the metering device 45 and the pump 50 pass through the exchanger 10 and carry with them the dép8ts. In the separator 30, they are separated from the working fluid of the exchanger which joins the pipe 13 through a valve 35; a large part of the waste is discharged through the pipe 65. The flow extracted by this pipe is compensated by a booster through the valve 74. The synthetic cleaning elements return to the cleaning cycle until the end of the cycle. operation which is controlled by the stopping of the pump 50. The latter is of lower capacity than in the case of the installation of FIG.

  low flow, of the order of 1/10 of that of the pump of the exchanger.

  The same installation can be used for the successive cleaning of several devices. All you have to do is provide piping sets

and appropriate valves.

-8-

Claims (3)

CLAIMS 1 / Cleaning element of an industrial device in which circulates a fluid capable of causing calcareous and biological deposits, said cleaning element being introduced in large numbers into the fluid and acting by mechanical action on the walls of the device, characterized in that it consists of an artificial grain (1) of a mixture of synthetic materials capable of withstanding a temperature of up to 150 degrees, the grain having a relative average density of between 1.02 and 1.5 and a particle size of between 140 and 3000 microns.   2 / cleaning element according to claim 1, characterized in   what for the cleaning of devices including tubes-d'un-   given diameter, the grain (1) has a grain size between   a tenth and a quarter of said diameter.   3 / cleaning element according to one of claims i and 2,   characterized in that for cleaning hard deposits, the grain   is loaded with abrasive particles.   14 / Apparatus for cleaning an industrial device in which a fluid circulates while the device is in operation, said fluid arriving at the device via an inlet pipe and starting from an outlet pipe, said installation using for cleaning the elements according to any one   Claims 1 to 3, said installation comprising means   for stopping the circulation of the fluid during the cleaning phase, characterized in that it comprises, in parallel on the device (10), a circuit comprising, successively arranged from the output of the device to its inlet, a liquid-solid separator (30 ) a storage silo (140), a metering apparatus (45) and a cleaning pump (50), a duct (60) being disposed between the inlet of said solid liquid separator (30) and the inlet of the booster pump (50); cleaning (50>, this pipe being connected by pipes (61,   63) respectively at the top and at the outlet of the liquid separator. solid (30).   / Installation for cleaning an industrial device in which a fluid circulates while the device is operating, said fluid arriving at the device via an inlet pipe and leaving it via an outlet pipe, said installation allowing the device to be cleaned during its operation   and using the elements according to any one of claims 1   3, characterized in that it comprises, in series with the device   tif (10), a solid liquid separator (30) and in parallel on the assembly consisting of the device (10) and the separator (30), a cleaning element storage silo (40) (1), a metering circuit (70, 71, 729 73) to ensure a determined proportion of elements measured by the metering device (45) in the fluid and a pump circulation (50).