FR2757088A1 - Cleaning procedure for domestic heating oil tank - Google Patents

Abstract

The tank cleaning procedure consists of pumping out the fuel oil (F) contained in the tank down to a level just above the surface of the sludge, transferring it to the first chamber (7) of a tanker vehicle (1), and pumping out the sludge (B) into a second chamber (8) on the vehicle. The inside of the tank is then cleaned with a jet of liquid delivered from a third chamber (9), and the used cleaning liquid is pumped out into the second chamber (8) containing the sludge. The oil is then pumped back into the tank after it has been dried, and the mixture of cleaning fluid and sludge is decanted so the cleaning liquid can be re-used. When the fuel oil is pumped out of the tank a flexible pipe with a special nozzle is used, having an intake situated above the level of the sludge. If necessary a hole is made in the top of the tank for the procedure and re-sealed afterwards.

Description

The present invention relates to a method for cleaning tanks or the like, as well as a mobile cleaning unit for carrying out the method.

In a preferred application, although not exclusive, the method and the unit are intended for the treatment of oil tanks of heating installations, in particular domestic, but it goes without saying that they could be used for other technical fields without depart from the scope of the invention.

We know that, over time, deposits called "sludge" by technicians gradually form in the bottom of oil tanks as a result of chemical and / or physical reactions such as oxidation. During the operation of the heating installation, this sludge is gradually pumped with the fuel oil, manages to pass through the strainer and ends up fouling the piping and the various components of the installation. This can lead to the failure of the installation.

Currently, to remedy these drawbacks, one solution consists of cleaning and / or replacing the damaged parts (nozzle, strainer, etc.) or moving the strainer away from the layer of sludge. If these interventions allow the installation to function again, the same problems caused by the sludge will reappear later, implying new interventions so that, ultimately, these only push back the problems posed above.

Another solution consists in emptying the tank, then cleaning the installation, but then the sludge contained in the tank mixes with the oil remaining in the tank, so that the oil-sludge mixture is lost for the particular.

In addition to these solutions, there are difficulties in implementing them since they depend on the accessibility of the tank (buried or on the surface), its shape (cylindrical, cubic, etc.) and its volume. .

Consequently, existing solutions often prove to be unsuitable as required.

The present invention aims to overcome these drawbacks.

To this end, the method for cleaning the tank of at least one heating installation or the like, from a mobile cleaning unit, is remarkable, according to 1 invention, in that it consists in - pumping the fluid contained in the tank to a level
minimum below which bottom sludge rests
tank, and transfer the pumped fluid to a first
tank of said unit - pump the bottom sludge and transfer it
to a second tank of said unit - clean the inside of the tank with a jet of
pressurized liquid from a third tank
the unit, then transfer by pumping said liquid after
cleaning to said second tank - return the pumped fluid contained in the cleaned tank
in the first tank; and - after settling of the sludge-liquid mixture, contained in
the second tank, recover the constituents of said
mixture to transfer them to additional tanks
separate.

Thus, the method according to the invention makes it possible to temporarily store the clean fluid (fuel oil) pumped into the tank of the individual, during the cleaning operations of the latter (suction of sludge, washing water and other residues diluted in the water of washing) and system components, and then return the clean fluid to the individual's cleaned tank.

Advantageously, before restoring the pump fluid in said cleaned tank, the interior of the latter is dried.

For example, a vacuum pump is used to pump the fluid, the sludge and the cleaning liquid, as well as to dry said tank, and a high pressure pump to clean said tank.

In addition, to pump the fluid contained in said tank, a specific tool is chosen which is a function of the height of the sludge contained in the tank, so that its suction orifice is located above said sludge. This ensures that you do not suck up sludge when pumping clean fuel.

In the case where the tank is not equipped with an access hatch, an opening is made in the upper part of said tank to allow the various pumping, cleaning and restitution operations, and then said seal is closed. opening carried out after the return of the fluid pumped into said tank.

The invention also relates to the mobile cleaning unit allowing the implementation of the above process.

For this purpose, the unit includes - at least first, second and third tanks
likely to contain respectively the fluid to be pumped
and to return, the sludge-cleaning liquid mixture
pumped and the cleaning liquid to be injected into said
tank - pumping means capable of bringing communica
tion the first or the second tank with said tank,
respectively to aspirate or return the fluid, or
to suck up said mixture, said pumping means
comprising a specific tool for maintaining, at a distance
from the bottom of the tank, the suction opening during pumping
fluid; and - high pressure cleaning means connected to said
third tank and likely to clean the interior
of the tank by a jet of cleaning liquid.

Advantageously, the three tanks constitute the three compartments of a tank, and said tank, said pumping means and said cleaning means are mounted on the chassis of a vehicle. Thus, such a unit can operate everywhere without requiring significant logistics, and also have a limited space since the volumes of the reservoirs are relatively small, for example an overall volume of less than three cubic meters, to allow the treatment of several tanks of 'installations.

In a particular embodiment, said pumping means comprise a vacuum pump capable of communicating with the first or second tank, and a suction pipe which is connected to one or the other of said tanks and to the the free end of which is fitted either said suction port tool for sucking said fluid, or a flexible hose for sucking said mixture or drying said tank. Said tool can then have a hollow cylindrical shape, one end of which is closed off and ends in a bottom capable of coming into contact with the bottom of the tank, and the other end of which is connected to a suction pipe, said tool being provided at least one lateral suction orifice remote from said bottom by a distance greater than the height of said sludge.

As for said high pressure cleaning means, they comprise a high pressure pump capable of communicating with said third tank, and a hose reel which is connected to said third tank and which is provided at its end with a controllable nozzle for set the operating pressure.

The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

FIG. 1 represents an exemplary embodiment of the mobile cleaning unit according to the invention, during treatment of the oil tank of a heating installation.

Figure 2 is a more detailed view of the mobile cleaning unit.

Figures 3 to 10 relate to the different stages of the method according to the invention.

FIG. 3A is an enlarged sectional view of the detail A of FIG. 3.

The cleaning unit 1, illustrated diagrammatically in FIG. 1, is intended, in its preferred application, to treat in particular the tank C with fuel oil F equipping heating installations IC of individuals, like that represented and which will be described in more detail thereafter. In order to guarantee easy access to the tanks to be cleaned, the unit 1 is mounted on the chassis 2 of a vehicle 3.

As shown in Figures 1 and 2, the unit 1 mainly comprises a tank 4, pumping means 5 and cleaning means 6. More particularly, the tank 4 has a cylindrical shape and it is divided into three internal compartments which correspond to first, second and third reservoirs 7, 8 and 9 respectively.

The purpose of the first tank 7 is to temporarily contain the fuel oil from the tank C to be treated, the second tank 8 collects the sludge from the bottom of the tank, and the third tank 9 contains, for its part, a cleaning liquid for the tanks treat.

The pumping means 5 comprise, in this embodiment, a vacuum pump 10, which can be placed in communication with the first reservoir 7 by means of a connector 7A provided in the upper part thereof, or with the second reservoir 8 via a connector 8A also provided in the upper part thereof.

A pipe 11 can be connected by one of its ends llA, to a suction connection 7B in connection with the first tank 7 or to a suction connection 8B in connection with the second tank 8. The other end llB depending on the type of suction chosen as will be seen later, the hose can be fitted with either a specific tool 12 with lateral suction nozzles, or a flexible hose 13.

The cleaning means 6 comprise a high pressure pump 14 communicating with the third tank 9, and a reel 15 provided with a pipe 16 connected to the pump 14.

The free end 16A of this pipe is provided with a controllable nozzle 17, or the like, making it possible to regulate the outlet pressure of the cleaning liquid which may be water possibly added with an appropriate washing product.

Note in Figures 1 and 2 that the vacuum pump 10 and the high pressure pump 14 are fixed to the chassis 2 of the vehicle, between the cabin of the latter and the front face 4A of the tank. On the rear face 4B thereof, there are provided the reel 15, the two suction connections 7B, 8B communicating respectively with the first and second tanks 7, 8 and located for example in the upper part of said face 4B, thus as the drain connection 8C of the second tank, located in the lower part of the rear face 4B. Furthermore, at the rear of the chassis 2, substantially under the rear face 4B of the tank, there opens a drain or discharge connection 7C coming from a pipe 7D emerging from under the first tank 7. Similarly, under the third reservoir 9, there is provided a pipe 9A for filling by suction and for draining the liquid, provided at its end with a connector, not shown in the figures but identical to those already illustrated.

Of course, according to another arrangement and for easier access, at least the suction fittings 7B, 8B and the discharge or drain fittings 7C, 8C could be arranged in line, at the rear of the chassis for example.

In addition, the mobile unit 1 is equipped with a safety filter tank 18 mounted on the chassis, close to the pumps, and ensuring optimum filtration of the fuel oil sucked in the direction of the first tank.

The method for cleaning the tank of the heating installation from the mobile unit 1 will now be described.

First of all, as shown in FIG. 1, the heating installation IC to be cleaned comprises, briefly, the tank C (buried or not) external to the dwelling, a boiler
CH arranged in the dwelling, a suction line CA for the fuel oil contained in the tank, which connects the interior of the latter to the nozzle G of the boiler and on which the suction pump P and filters FL are mounted , and a discharge pipe CR connecting the outlet of the pump P, via a valve CL, inside the tank. The suction line CA is provided, at its end located in the tank, with a strainer CP immersed in the fuel oil F and arranged near the sludge B lying at the bottom of the tank and capable of being sucked into the line CA with fuel oil, risking fouling and damaging the boiler.

As shown in FIGS. 1 and 3, the method consists in pumping the clean fuel oil F contained in the tank C. For this, the vacuum pump 10 is placed in communication with the first tank 7 of the tank, and the pipe 11 is connected, by its end llA, to the connector 7B connected to the inside of the tank 7. Its other end 11B is introduced into the tank C through its access hatch T. If the pipe 11 turns out to be too short due away from the tank, one can add a reserve pipe provided on a reel 19 which is arranged on the rear face 4B of the tank.

In order not to vacuum the sludge B (or deposits) located at the bottom of the tank, the end 11B of the pipe 11 is equipped with a specific tool 12 which is more particularly illustrated in FIG. 3A. This tool 12 has the shape of a hollow cylindrical end-piece, one end of which is closed off by a flat bottom 12A capable of coming into contact with the bottom CF of the tank, and the other end of which 12B is open for connection, in an appropriate manner, at the end 11B of the pipe. Side orifices (or nozzles) 12C are provided in the wall 12D of the tool, and the distance D from these lateral suction orifices at the bottom 12A is such that it is greater than the height H of the sludge contained in the tank. .

Thus, since the lateral orifices 12C are located above the sludge, only the clean fuel oil F is sucked by the pipe 11, in the direction of the first tank 7. Of course, depending on the height of the sludge, the most suitable tool will be chosen suitable for pumping as much fuel as possible without sucking up the sludge.

When the clean fuel oil F is in the tank 7 of the tank, the specific tool 12 is removed from the pipe 11, then a flexible pipe 13 of smaller diameter is fitted at its end 11B. This flexible pipe 13 is then engaged in the tank C through its access hatch T, until it comes into contact with the sludge. The vacuum pump is then placed in communication with the second reservoir 8, and the pipe 11 is placed on the suction connection 8B. The pumping of the sludge B by suction can then begin, as indicated in FIG. 4. Thanks to the flexibility of the pipe 13, the bottom CF of the tank can be treated at best.

After pumping the sludge in the direction of the second tank 8, the process consists in cleaning the tank C. For this, the high pressure pump 14 is put into service and the pipe 16 mounted on the reel 15 is brought to the tank access hatch T. The washing water contained in the third tank 9 of the tank leaves the nozzle 16B equipping the free end 16A of the hose, under high pressure, which can be adjusted by the user by means of the nozzle 17. Thanks to the shape curved nozzle and pressure control via the nozzle, the internal walls of the tank C can be properly cleaned, as shown in Figure 5.

After stopping the high pressure pump 14, the process consists in sucking the dirty cleaning liquid mixed with residues and located in the tank. For this, as shown in FIG. 6, the vacuum pump 10 puts the second tank 8 of the tank under vacuum, and the flexible pipe 13, extending the pipe 11, is introduced into the tank. Such an operation makes it possible to suck up the dirty cleaning liquid and dry the interior of the tank at the same time, so that the latter is considered to be cleaned.

As a variant, it would be possible, after pumping the clean fuel oil, to clean the tank by the jet of liquid at high pressure, then to suction the sludge and the liquid contained in the tank, in the direction of the second tank.

Similarly, we take advantage of the clean tank to clean and / or change the various components of the installation (filters, conduits, strainer, etc.), if necessary.

Then, after removal of the pipe 13, the pipe 11 is engaged in the tank while its end 11A is then connected to the connector 7C of the first tank 7. The clean fuel oil F initially pumped is then returned to the tank C of the installation of IC heating, so that the individual thus recovers almost all of the fuel, as shown in Figure 7.

In the case where the tank does not have an access hatch or if this is too narrow for the passage of the pipes, or even if the length of the tank is such that a single access orifice is not enough to perform a total cleaning of the tank, it is then necessary to make a inspection hatch in the upper part of the tank. For this purpose, as shown in Figure 8, we cut three of the four sides of a square drawn on the upper face FC of the tank
C, and the cut square part forming the hatch is folded around the fourth side to access the tank through the opening thus created. After cleaning as described above, the hatch T is folded down substantially in the plane of the upper face FC, thereby closing the opening. Then, as indicated in FIG. 9, a PG tar-based plate, for example, is placed and then glued to the hatch, completely covering it, and an MA sealant is deposited around it, as well as, beforehand , around the three cut sides of the hatch.

The mobile unit 1 makes it possible to treat several tanks of heating installations in the same day. For example, taking into account the use of approximately 50 liters of washing water per tank and knowing that the third tank 9 of the tank 4 can contain approximately 250 liters, the unit 1 can proceed with cleaning. of five tanks in one day. This gives it significant autonomy which could of course be increased depending on the size of the tank. However, it is noted that such a small mobile unit allows easy and quick access to the various tanks, without thus resorting to much heavier vehicles. Indeed, the volumes of the first and second tanks are of the order of 1500 liters and 1000 liters respectively, so that the tank 4 and its ancillary equipment (pumps, reels, ...) can be mounted on a light vehicle, like the one shown in figure 1.

After cleaning the various tanks of separate installations, the vehicle carrying the unit returns to its starting site and the aspirated material is allowed to settle, contained in the second tank 8 and consisting of sludge, washing water and fuel oil. After settling of the material, the constituents of the material are removed to be transferred separately into respective auxiliary tanks 21A, 21B, 21C receiving water, sludge and fuel oil respectively, as shown in Figure 10. After emptying tank 8 and filling tank 9 with clean wash water, unit 1 is operational again.

Claims (10)

1. Method for cleaning the tank of at least one heating installation or the like, from a mobile cleaning unit, characterized in that it consists in - pumping the fluid contained in the tank (C) up to a  minimum level below which sludge rests  tank bottom, and transfer the pumped fluid to a  first tank (7) of said unit - pump the bottom sludge and transfer it  to a second tank (8) of said unit - clean the inside of the tank with a jet of  pressurized liquid from a third reservoir (9) of  the unit, then transfer by pumping said liquid after  cleaning to said second tank (8) - return the pumped fluid contained in the cleaned tank  in the first tank (7); and - after settling of the sludge-liquid mixture, contained in  the second tank (8), recover the constituents  said mixture to transfer them to tanks  separate annexes. 2. Method according to claim 1, characterized in that, before restoring the pump fluid in said cleaned tank, the interior thereof is dried. 3. Method according to one of claims 1 or 2, characterized in that a vacuum pump (10) is used to pump the fluid, the sludge and the cleaning liquid, as well as to dry said tank, and a high pressure pump (14) for cleaning said tank. 4. Method according to any one of claims 1 to 3, characterized in that, to pump the fluid contained in said tank, we choose a specific tool (12) which is a function of the height of the sludge contained in the tank, so that its suction port (12C) is located above said sludge. 5. Method according to any one of claims 1 to 4, characterized in that an opening is made in the upper part of said tank to allow the various pumping, cleaning and restitution operations, and then it is closed, with sealing , said opening made after the return of the fluid pumped into said tank. 6. mobile unit for cleaning tanks, in particular heating installations or the like, intended for implementing the method according to any one of the preceding claims, characterized in that it comprises - at least first (7) , second (8) and third (9)  tanks likely to contain respectively the  fluid to be pumped and returned, the sludge-liquid mixture  cleaning fluid pumped and cleaning fluid to be injected  in said tank - pumping means (5) capable of  communication the first or the second tank with  said tank, respectively for aspirating or restoring the  fluid, or to aspirate said mixture, said means of  pumping comprising a specific tool to maintain, at  distance from the bottom of the tank, the suction opening when  pumping the fluid; and - high pressure cleaning means (6) connected to said  third tank and likely to clean the interior  of the tank by a jet of cleaning liquid. 7. Unit according to the preceding claim, characterized in that the three tanks constitute the three compartments of a tank (4), and in that said tank, said pumping means and said cleaning means are mounted on the chassis (2 ) of a vehicle (3). 8. Unit according to one of claims 6 or 7, characterized in that said pumping means comprise a vacuum pump (10) capable of communicating with the first or the second tank, and a suction pipe (11) which is connected to one or the other of said reservoirs and to the free end of which is adapted either said tool (12) with suction orifice for sucking said fluid, or a flexible pipe (13) for sucking said mixture or drying said tank. 9. Unit according to claim 8, characterized in that said tool has a hollow cylindrical shape of which one end is closed and ends with a bottom (12A) capable of coming into contact with the bottom of the tank, and whose other end (12B) is connected to a suction pipe, said tool being provided with at least one lateral suction orifice (12C) distant from said bottom by a distance greater than the height of said sludge. 10. Unit according to any one of the preceding claims 6 to 9, characterized in that said high-pressure cleaning means comprise a high-pressure pump (14) capable of communicating with said third tank (9), and a reel ( 15) with pipe (16) which is connected to said third tank and which is provided at its end with a controllable nozzle (17) for adjusting the operating pressure.