A METHOD FOR CANCELLING OF SUBTERRANEAN TANKS BY FILLING

Abstract: By a method for cancelling of condamned subterranean tanks by filling is used compressed air to convey the filling material (14) through a hose (1) from a pressure vessel (16) placed in substantial distance from the subterranean tank (2) and to inject the filling material into the subterranean tank (2) for the filling thereof. The cancelling of subterranean tanks thus obtained is simple, cheap, and careful with respect to the surroundings, as the work may be performed without noticeably intervention in surrounding areas such as gardens, terraces etc.

Description: A Method for Cancelling of Subterranean Tanks by Filling. The present invention relates to a method for can¬ celling of subterranean tanks by filling. Out of consideration for environment special regu¬ lations apply as to subterranean tanks, e.g. oil tanks of steel. Such subterranean oil tanks are not allowed to be used beyond a maximum, of 20 years, if not provi¬ ded with a cathodic protection system or another autho¬ rized protection against leaking out of oil due to cor¬ rosion. By cancelling subterranean oil tanks the autho- rities require either a digging up of the tank or a filling thereof with a steady inorganic material, e.g. sand. Alternatively, a- subterranean tank can be cancel¬ led by concreting. The major part of condemned subterranean tanks are oil tanks in private oil heating systems, i.e. the tanks in question mainly are smaller subterranean tanks with a volume of up to 4000 litres. The said environmental demands relating to maximum age of subterranean oil tanks of steel came into force in 1960 which means that rather many subterranean tanks from the period up to 1960 now have passed said age li¬ mit and consequently must be claimed cancelled. Most of these obsoleted subterranean tanks - which as mention¬ ed are smaller private tanks - are buried in private gar- dens. Of course, this involves relatively high costs for such private tank owners; however, the main disad¬ vantage by the cancelling or removal of private subter¬ ranean oil tanks is by most people considered to be the resulting "destructions" of gardens, drives, terraces, and similar surrounding areas of private estates. It is the purpose of the present invention to provi¬ de a method of cancelling subterranean tanks by filling which method means a cancelling of subterranean tanks which is simple, cheap, and careful with respect to the surroundings. The method according to the invention is characteriz¬ ed in that a pressure medium is used to convey the fill- ing material and to fill up the subterranean tank through a hose from a pressure vessel positioned in some dis¬ tance from the subterranean tank, said pressure tank a. priori being supplied with the filling material. The method of cancelleing subterranean tanks thus obtain- 0 ed is simple, cheap and careful with respect to the sur¬ roundings, as the filling in of the tank hereby may be effected without any digging or only with a minimum of digging wo «rk at the subterranean tank. The pressure fil- ling tank may during the filling operation be placed in -5 some distance from the subterranean tank, e.g. right outside the affected garden or estate. The filling ope¬ ration as a whole may be performed by one or two per¬ sons within a few hours, i.e. the method according to the invention involves a minimum of costs and a good 0 possibility of careful affecting of the surroundings of the subterranean tank. According to claim 2 compressed air is preferably used as conveying medium to convey the filling material and to the filling in of the tank cavity, i.e. a pressure 5 tank is used in the form of a spherically shaped vessel into which the filling material is supplied through a tightly fitting top cover. At the top of the spherical vessel compressed air is fed in in order to establish an auxiliary conveying pressure above the filling materi- 0 al which appropriately is led into the lower outlet ope¬ ning by means of a loosening mixerlike device whereby the filling material without difficulty may be fed into the injector nozzle and the conveying hose. According to claim 3 the usual filling stud of the subterranean tank 5 m be used for the blowing in of the filling material if said filling stud does not have a too long and com- plex filling tube. However, according to claim 4 an ope¬ ning is preferably cut in the top side of the subterrane¬ an tank since appropriately an angle shaped feed-in nozzle is used to disperse the filling material. As a particu- lar advantage may be emphasized that according to claim 5 common grossly sand is used as filling material - and without the sand needing any form of preliminary treat¬ ment, e.g. it is not necessary to dry the sand at all. Preferably, the tank cancelling is started with sucking the subterranean tank empty for removal of the rest oil and bottom sediment, if any, but, anyway, it may be ap¬ propriate to add an oil absorbing or oil neutralizing material, preferably in powder form, at least to the first portion of the filling material. The invention is described in more detail in the following, reference being made to the accompanying draw¬ ing in which:- Fig. 1 is a draft in principle to illustrate the method according to the invention, while Fig. 2 shows a pressure vessel for use by performing the invention. In Fig. 1 is shown a subterranean tank 2 during can¬ celling by the method according to the invention. The sub¬ terranean tank 2 is buried in a considerable distance from the road. A topside portion 4, preferably at the filling stud of the tank, i.e. opposite to a ventilation stud 6 has been digged free and an opening 8 has been cut in the top side portion 4. A blowing in nozzle 10 is mounted at the end of a relatively long thick hose 12 through which filling material in the form of common pit sand 14 is injected to fill in the tank 2. On the road a pressure tank or vessel 16 is position¬ ed having spherical shape because the compressed air used to convey the sand 14 has a pressure of e.g. 8 ato. The spherical vessel 16 is supplied with sand from a lorry 18 through a tight fitting top opening 20 manually or by means of a conveying device 22. Furthermore, on the platform of the lorry is placed a compressor 24 which supplies the spherical vessel 16 with compressed air. From the vessel 16 the filling sand 14 is led out through a lower outlet opening 26 by means of a loosening mixer device 28 (Fig. 2) and being conveyed to the subterranean tank 2 and injected therein through the hose 12 and the nozzle 10. The spherical vessel 16 has diameter of some 100 cm, i.e. that it may contain about 500 litres of sand. When the spherical vessel 16 is emptied it may be refill- ed with sand from the lorry 18 and this cycle is repeated until the subterranean tank 2 is completely filled with sand. The top opening 8 is made big enough for an ample ven¬ tilation of the conveying air taking place ' during the tank filling operation. Experimentally was used common pit sand and the dis- stance between the spherical vessel 16 and the subterra¬ nean tank 2 was about 80 metres, compressed air at 8 ato 3 and an air volume of about 6 m /min. was used. The sub¬ terranean tank 2 which in this case was an above ground experimental tank provided with suitable inspection open¬ ings was completely filled in with close-packed sand which during a control period of some months has not settled very much. For use by the method is developed the spherical ves- sel 16 shown in Fig. 2 which as already mentioned has a diameter of some 100 cm or a volume of about 500 litres. The filling material or the sand 14 is filled in through the top opening 20 which is provided with a tight fitting cover 28 with a locking mechanism 30. When the sand 14 is filled in the spherical vessel 16 said vessel is set under pressure as compressed air from the compressor 24 (Fig. 1) is connected at 32 so as to establish a convey¬ ing pressure above the sand 14 in the vessel 16 via the tube connection 33. Simultaneously a loosening mixer de- vice 34 is started which device is driven by means of an exterior hydraulic or pneumatic motor 36 in order to IΌ ___ o Lπ o

Claims: C l a i s : 1. A method for cancelling of subterranean tanks by filling with a steady inorganic material, characterized in that a pressure medium is used to cbnvey the filling material and to fill up the subterranean tank (2) through a hose (12) from a pressure vessel (16) positioned in some • distance from the subterranean tank (2), said pres¬ sure vessel (16) being previously supplied with the fill¬ ing material. 2. A method according to claim 1 , characterized in that compressed ais is used as pressure medium, that an air pressur * e is established above the filling material (14) in the pressure vessel (16), that the filling ma¬ terial (14) is agitated at a lower outlet opening (26) of the pressure vessel (16) for injecting the filling ma- terial (14) into an injector nozzle (40) and that com¬ pressed air is supplied to the injector nozzle (40) for conveying the filling material (14) through the hose (12) to the subterranean tank (2) . 3. A method according to claim 1 or 2, characterized i that the usual filling stud of the subterranean tank (2) is used for the blowing in of the filling material as the subterranean tank (2) is simultaneously ventilat¬ ed through its usual ventilation stud (6) . 4. A method according to claim 1 or 2, characterized in that a top side portion of the subterranean tank (2) is laid open and an opening (8) is cut therein, and that an injecting nozzle (10) is used in the form of an angular bended tube by means of which the injected filling mate¬ rial is distributed in the whole tank (2) . 5. A method according to claims 1-4, characterized in using common grossly sand (pit sand) as filling materi¬ al. 6. A method according to claims 1-5, characterized in adding to the first portion of filling material an oil absorbing and/or oil neutralizing material.

Inventors: BURMEISTER RUHDI
Applicants: BURMEISTER RUHDI, ERVALD & CO AS H C
Application year: 1982
Main classification: B65D90
IPC codes: B65D88, B65G53