EP1169888B1

EP1169888B1 - Device for static eletricity elimination used during racking, transportation and loading/unloading of inflammable or explosive materials

Info

Publication number: EP1169888B1
Application number: EP99903523A
Authority: EP
Inventors: Mico Gacanovic
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-02-15
Filing date: 1999-02-15
Publication date: 2004-01-14
Anticipated expiration: 2019-02-15
Also published as: DE69914225T2; CA2401517A1; EA200100781A1; DE69914225D1; ATE258005T1; CA2401517C; AU2352799A; WO2000048434A1; EA003411B1; EP1169888A1

Abstract

Device for the elimination of static electricity used for the racking, transportation and loading/undloading of oil and oil derivatives, inflammable gases and solid inflammable materials consisting of the two energy branches one of which is connected to the object (12), the energy of which needs balancing, and the other to the ground-coupled plate grounding (78). The first energy branch consists of the crocodile clamp (33), cable (44), diode (D1), condensers (C1) and (C2) and glittering diode (T1). The second energy branch consists of the ground-coupled plate grounding (78), cable (55), resistors (R3) and (R1), condensers (C3) and (C4) and diode (D2). The branch for the energy level exchange of the created electrostatic energy consists of condensers (C2), (C3) and resistor (R2). The operation of the device is based on energy balancing between the electrostatic cumulative points of two systems bearing different energy levels, in the concrete case, cistern with oil and part of the ground where the cistern is placed.

Description

(A) Prior state of art to which the invention refers

The invention belongs to the field of devices for the elimination of static electricity and according to the International Patent Classification (IPC), it can be classified in the classes B 65 D 90/46 and H05F.

(B) Technical problem

At the time of racking (loading/unloading) and transportation of oil and oil derivatives, inflammable gases and liquids, explosive materials (explosives) or solid inflammable materials performed at terminal loading facilities for vehicles, shipyards with tanker racking terminals, at towed vehicles or trailers in motion and other chance objects, individual cars and similar geometries, a problem arises of how to execute the elimination of static electricity which appears while performing the above mentioned technical operations.

Unless such elimination is performed, there is latent danger to provoke fires, explosions, disturbance of the technological production process development and the effect of superposed circuit on bio and electrostatic field ( leading to the disturbance of psychophysical condition of the employed workers).

By means of the suggested technical solution expostulated in the application, which is simple, reliable and easy for maintenance, handling and storage, one avoids the above mentioned latent hazards provoked by static electricity.

(C) State of the Art

The present solutions for the elimination and discharge of static electricity with regard to the mentioned technological operations, stipulated in the title of the application are

direct grounding of the observed geometry
solution by means of grounding with unipolar cam shaft of the observed geometry (volume),
solution by grounding with the grounding detector of the observed geometry (volume),
anti-static band (transparent band- to connect in the electric sense of the word, the observed geometry with Earth) on towed vehicles and trailers.

In general, all the existing solutions can be reduced to the principle of grounding. Technical solutions utilizing the principle of grounding are described in the state-of-art report consisting of the bellow mentioned patent documentation and non-patent literature.

patent documents US 4 345 297, US 4 319 303, US 3 893 004, US 3 895 260, US 3 896 340, SU 1535780 A1, US 3 893 003, CH 653 643 A5, P-1302/75 (applicant Texaco Development Corporation USA).
non-patent literature
(a) THE AVOIDANCE OF ELECTROSTATIC HAZARDS IN THE PETROLEUM INDUSTRY, Journal of Electrostatics, Vol. 27 (1992)by H.L. Walmsley.
(b) W.M.BUSTIN & W.G. DUKEK ELECTROSTATIC INPETROLEUM INDUSTRY, Southampton, 1983.
(c) Joseph M. Crowley FUNDAMENTALS OF APPLIED ELECTROSTATICS, New York, 1986.
(d) J.S. Mills & R.C. Oldham EVALUATION AND PREVENTION OF ELECTROSTATIC HAZARD ASSOCIATED WITH OIL TANKER OPERATIONS, New York, 1983.
(e) Scientific and research project-Energoinvenst Sarajevo, SIZ nauke BiH Sarajevo, Faculty of Electronics in Sarajevo titled THE EXPLORATION OF PHENOMENON OF STATIC ELECTRICITY UNDER CONDITIONS OF EXPLOITATION, PROCESSING, TRANSPORT, HANDLING AND STORAGE OF OIL AND OIL DERIVATIVES AT THE EXAMPLE OF OIL REFINERY Bosanski Brod, Sarajevo, 1987.
(f) Scientific and research project titled VRELO-SSNO-SFRJ, Belgarde and Faculty of Electronics, Sarajevo, Sarajevo-Beograd, 1981.

All these solutions have more faults, which can be reduced to the fact that they do not completely eliminate and remove static electricity and thus endanger the working and technological discipline and everyday life with regard to the discussed technologies.

The results of it are the latent hazards provoked by static electricity and manifested in fires and explosions, then the disturbance of the technological process development and the effect of the superponed circuit on the bio and electric field.

The existing solutions of elimination and discharge of static electricity are reduced to one solution, namely grounding with several operational variations. Thus, a conclusion has been reached that it is quite enough and necessary only to ground the mentioned geometries-volumes utilized in the technological process during racking, transportation and loading/unloading of oil and oil derivatives, inflammable gases and liquids, explosive materials (explosives) and solid inflammable materials and thus eliminate and discharge static electricity.

The appearance of static electricity is a natural process- stochastic process as the result of technological process development and everyday life, and the discussion and conception of the problem must, thus be observed and studied. Static electricity is, however, the result of the superimposition of two layers (speaking plainly a result of friction).

Every technological process or action is characterized by certain parameters and possible outcomes. The discussed technological process or the result of mentioned technological operations (as defined in the title) are characterized by the presence of the concentration of explosive compounds. The existing compound can be lit by a spark with the minimal ignition energy. If the grounding of the observed geometries-volumes is secured, it will produce sudden immediate balancing of energy by discharge between the electrostatic energy cumulative points which are found distributed over the ground and volume of the observed geometry (in the concrete case, fuel-carrying vehicle) and Earth (ground coupled system as a point of reference). Earth as geometry or body possesses the greatest energy level with regard to all the other bodies (geometry□s) placed and maintained on Earth.

It results in the sudden and cumulative discharge (by lightening impulse or spark) between the discussed cumulative points of electrostatic energy with the predetermined sign, so the observed object can be considered as if it were isolated and balanced by electrostatic system with regard to the other system. If, on the observed object (concerning a discussed technological process - operation), the mentioned technological operations are performed and if the mentioned object, as an isolated electrostatic system we might wish to connect forcibly to some other observed electrostatic system (in the concrete case, a fuel-carrying vehicle, directly connected to a coupled grounding earth plate by band) it will forcibly produce balancing of electrostatic energy cumulative points.

The direct result of so observed technological operation process is the latent hazard manifested by the explosive mixture inflammation (in the case under observation, oil and oil derivatives combine with air producing the concentration of explosive mixtures) resulting in fire and explosion.

A question arises what will happen if the discussed geometry or volume remains permanently grounded (concretely, an oil cistern), what will it lead to!

As a result, the observed electrostatic system will be characterized by the presence of the electrostatic cumulative energy points, representing no longer an isolated and balanced system, but it will provoke the need for electrostatic balancing between electrostatic energy cumulative points in the interior and on the surface of the discussed volume-object. That will escalate into a condition of cumulative discharge (lightening impulses or sparkling) with the sufficient minimal energy of ignition necessary to ignite the explosive mixture. Actually, in such a way, we provoke latent hazards induced by static electricity at the mentioned technological operations manifested by fires and explosions.

Thus, grounding is nothing but a particular case of the elimination of static electricity, but it cannot serve as a sufficient measure for the elimination of static electricity, particularly with the technological processes or operations we observe, namely, racking, transportation and loading/unloading of oil derivatives, inflammable gases and liqiuds, explosive materials (explosives) and solid inflammable materials- because it can provoke fire and explosion. There is no need to discuss the discharge of static electricity into Earth.

The aim of the invention has been to produce a device for the removal of static electricity without external input drive that will produce energy balance between the power points of electrostatic energy discussed (concretely, an oil cistern and part of the Earth ground where a ground-coupled plate is placed ) so as not to produce a cumulative discharge by lightening impulses or sparkling. (As it has previously been said, lightening impulse or sparkling with enough energy to ignite the concentration of explosive mixtures.)

D.) The essence of the invention

The device for the elimination of static electricity (stated in the title of an invention) consists of a cage used for the implant of energy chip, tin roof for the fastening of the box, a column bearing on one side a cage with the device and on the other side three branches, is placed into the ground, two cables, one of which serves for the connection of the device with the considered geometry (concretely, cistern with oil) and the other which serves for the connection of the device with the ground -coupled plate, crocodile clips for the fixing of cables on the considered geometry (object), branch for the connection of that device with the ground-coupled plate grounding and crotches for the winding of cable with the clamps. (The winding of the cable can be resolved by means of an automatic roller, too. The device can also be placed without a column if so demanded by technological and operation circumstances.

The operation principle of this device is characterized by enabling balancing of energy between electrostatic cumulative points on the considered geometry (for example- oil cistern) and ground-coupling with Earth, and not to use during its operation energy of external feed, and thus it belongs to the group of passive devices. The feed of that device is secured from the existing resources of energy at the cumulative points of electrostatic energy of the two considered electrostatic systems. The device is characterized by simple handling, maintenance and storage.

E. ) Short description of the figures in the drawing

The device for the static electricity elimination and discharge is shown in the drawing, in particular-

Figure 1.) shows schematic appearance of the device,
Figure 2.) shows electric scheme of the energy chip,
Figure 3.) shows the manner for the adhesion of the device to the fuel―vehicle.

F) DETAILED DESCRIPTION OF AN INVENTION

The device shown schematically in Figure 1, consists of the following elements-cage 11, made and shaped according to operating conditions for a specified purpose in which an energy chip 22 is placed on a specified supporting board, fastened by bolts in the inside of a cage, tin roof 99 fastened by bolts on column 77, bearing a tin roof and a cage, cable 44 ending in crocodile clamps 33, cable 55 which connects device at the branch 66, that has been attached by bolts on column 77, with the ground-coupled grounding 78.

On the column 77, jaws 121 have been welded which serve for the rolling and storage of cable 44, after the completion of the process of elimination of static electricity. At its end, column 77 has three welded branches 100, which serve for the fixation of the column 77 and are placed with a part of column 77 in the concrete pedestal 78.

In figure 2, a detailed electrical scheme has been shown of the energy chip 22 which is sealed up in the cage 23 specially constructed for the establishment and implant in zones of danger and possible explosion. The cage 23 is specially elaborated, treated, prepared and filled up with a special mass and then placed on a special supportive board fastened by bolts in the inside of the cage 11. The cage 11 is prepared for the adhesion of a supportive board of the cage 23. The place of connection of the clamps 33 through cable 44 is determined in point 1, and the place of connection of the band 78, functioning in the part of ground-coupling, is determined in point 8. Point 9 is a place of connection of the cage 11 to point 8.

The first energy branch of the device is constituted by elements connected between the

points

4,5,1,2,and 3. That branch of a device consists of a parallel connection between a condenser C and neon-glow lamp T1 in

points

2 and 3, or 1 and 3, condenser C2 connected between the points 3 and 4 and diode D1 connected between the

points

1 and 4 or 5 and 4. The constituent part of the first energy branch also includes a cable 44, which ends in an isolated crocodile clamp 33, which is placed on the mentioned object 12.

The second energy branch consists of a parallel connection between a resistor R3 and condenser C4, connected between the

points

7 and 8, and the resistor R1 connected between the

points

7 and 3, diode D2 connected between the

points

6 and 7 and condenser C3 connected between

points

3 and 6. The constituent part of the second energy branch is a cable 55 by which the device is connected to the band (ground-coupled grounding plate) 78. Then ground-coupled plate grounding 78 is observed as a point of reference and need not always appear as it has been shown in figure 2.) (connection with the ground), but another point of reference may be chosen on another cumulative point of electrostatic energy. The resistor R2 is connected between the points 4 and 6.

The elements connected between the

points

4, 6 and 3,i.e condensers C2 and C3, and the resistor R2 are elements of a branch for the exchange of the energy levels of the created electrostatic energy.

In figure 3, the way of connecting the device 11 to the cistern vehicle 12 has been shown. We should mention here that the manner of connecting is the same for all discussed geometries-volumes. Also, instead of the isolated crocodile clamps, it is possible to use the isolated clamp.

The operation of the device for the elimination of static electricity, is used for the racking, transportation and unloading of oil and oil derivatives, inflammable gases and fuels and alike (as it has been defined in the title of the application), and it is based on the balancing of energy between the electrostatic energy cumulative points defined by time constants of the electrical field (in the field of electric and volume resistance), from the point of view of static electricity, so as not to produce cumulative discharge (lightening or sparkling).

There are two separate electrostatic energy systems (which are characterized by the cumulative points of electrostatic energy) whose energy levels should be balanced, one is the Earth surface where a ground-coupled plate 78 is placed, and the other is, concretely, the cistern with oil, the electrostatic energy of which should be balanced with regard to the first system (because it always invariably possesses higher energy potential).

As the referral point for the energy balancing between the electrostatic energy cumulative points of those two systems, we have chosen a point of the ground-coupled plate 78.

By controlling the balancing of energy levels of those two systems, we avoid the possibility of cumulative discharge not only on the surface but also in the interior of the observed geometry-volume (in the concrete case- the oil cistern), and it is essential and necessary to accomplish this.

On the side, in this case, of the cistern with oil (or any other observed geometry-volume), we have the first branch for the electrostatic energy balancing which encompasses elements of the electric circuit marked by 33, 44,C1,T1, C2, D1 and on the side of the ground-coupled plate grounding, there is the other branch for electric balancing comprising elements of electric circuit marked with 78, 55, R3, C4, D2, R1, C3.

The branch of the elements C2, C3 and R2 connected between the

points

3,4 and 6 is the branch for the exchange of the energy levels of the created electrostatic energy of the first and second branch (of the two energy systems and the above discussed systems).

By defining time constants in the sphere of electric resistance and in the field of volume resistance from the point of view of static electricity, I have chosen the condensers C1,C2, C3 and C4 and resistors R1,R2,R3 and diodes D1 and D2 and the neon-glow lamp T1 (which serves to define the critical breakdown voltage, or defines the energy of the glittering discharge in the considered case).

The exchange of energy levels between the cumulative points of electrostatic energy of the two above discussed systems is performed through the glittering discharge defined in time constants and it is harmless for the considered technological operation (defined in the title of an invention).The duration of the exchange of electrostatic energy between the two energy levels of the two mentioned systems until balancing, is defined by time constants in the field of electric and volume resistance determined and defined in the manner defined in the text above.

The energy chip which enables the function of the elimination of static electricity by the method of energy level exchange (method of balancing) between the storage points of electrostatic energy of the two above discussed, non-isolated systems, consists of elements shown in figure 2. The choice of the given elements is performed depending on the kind of the material chosen characterized by electric, surface and volume resistance.

The number of energy exchanges between the energy levels of the considered cumulative points of electrostatic energy also depends on the kind of dangerous material under discussion.

Every dangerous material is characterized by electric, surface and volume resistance, and on the basis of it we determine time coordinates (time of relaxation, produced by contact, of the double layer fold) and from the value of the time constants we perform calculations and choose electric elements which enable the functioning of energy chip.

We also make the choice of electric elements of the energy chip, kind and length of that geometry of extension with the plug and storage of cable 44 and 45 on the vehicle-cistern 12 and ground-coupled plate grounding 78, performed on the basis of energy exchange between the cumulative points of electrostatic energy.

Because the appearance of static electricity is the result of the contact of that double layer, and thus a natural process, we observe that the sign plus + or minus - preceding the charge of the electrostatic cumulative point (concretely, oil cistern 12) may be changed in the unit of time (and such is also the charge of the ground-coupled plate grounding 78).

So, in order to describe the functioning of the energy chip 22 and the device as well (indicated in the title of the application) we should reconsider all the possible combinations of signs preceding the discussed electrostatic cumulative points. In the concrete case, we define the possible combinations- on the oil cistern 12, the signs are as follows + -+ - , and then the voltage on the ground-coupled plate 78 with regard to the preceding signs results in the following order - + + -.

In the description, let us consider the case of the sign preceding the charge of the considered cumulative points of electrostatic energy on the cistern 12, sign plus + and on the ground-coupled plate sign plus + as well. From the cistern 12, by means of a clamp 33, cable 44, point 5, diode D1, point 4, condenser C2, point 3, resistor R1, point 7, condenser C4, cable 55 leading to the ground-coupled plate grounding 78, in the point of time equals zero, the current of balancing electricity will flow. On that way of the flow of electric currency of balancing ,the charging of condenser C1, C2 and C4 will occur.

On the other hand, as the sign of the charge of the considered electrostatic energy cumulative points of the ground-coupled plate grounding 78 is plus +, the electric current of balancing will flow through the resistor R3, point 7, diode D2, point 6, condensed C3, point 1, cable 44 and crocodile clamp 33 to the cistern 12, and also, in a point of time, t equals zero.

In addition, on that way of the flow of electric current of balancing, a charge of the condenser C3 and C1 will occur. All this should take place in a relatively short interval of time without resulting in cumulative discharge.

The electrostatic energy will be redeemed by condensers and so, the first condenser C1 will transmit its electrostatic energy to the neon-glow lamp T1 and condensers C2 and C3 will mutually transmit the electrostatic energy from one to the other through the resistor R2 (by the correct choice of C2 and C3 in the function of the number of energy exchanges among the energy levels of the considered electrostatic energy cumulative power, which is again in the function of the kind of the dangerous material considered).The operating area of the energy chip 22, and also a device, is in the field of volume resistance.

All other discussed cases with the signs of the charge of the observed electrostatic energy cumulative points are reconsidered in the same way and can be examined in the impulse or some other operating regime.

Every analysis boils down to the fact that the solution enables us to avoid and prevent cumulative discharge (by lightening impulses or sparkling) which has been the purpose of this device. The condition is fulfilled for the device to have positive character, i.e. not to be driven by external energy which is very important for its implant in the areas of danger and explosion zones.

The technical solution in the described device (indicated in the title of the application) is based on the entirely new approach to the elimination of the static electricity (as described in the application). Unlike the known solutions in the state of the art, this device does not direct the discharge of static electricity towards the Earth, but only the balancing of energy levels between electrostatic cumulative points in the two systems. This device is the new constructive solution in the domain of such types of devices and enables complete safety and reliability of work of the mentioned operations from the point of view of those hazards provoked by static electricity. This device is tested and examined in real operating conditions and its application is checked during the performance of the mentioned technological operations (racking, transportation and unloading) with 816 dangerous materials (as designated in the annex to this application and forwarded with the text of the description). For each of the above mentioned described materials, one must perform appropriate dimension evaluation oOf electric elements in energy chip, depending on the electric characteristics of the material in question (electric, surface and volume resistance).

Claims

A device for the elimination of static electricity during the racking, transportation and unloading of oil and oil derivatives, inflammable gases and fluids, explosive materials and solid inflammable materials, said device performing energy balancing between points having different levels of accumulated electrostatic energy,
characterized in that the device comprises a circuit sealed in a cage (11), said circuit having two external connections, the first (1) of which is connected by means of a crocodile clamp (33) to the point (12) whose electrostatic energy is to be balanced via a first cable (44) and the second of which (8) is connected to the said cage (11) and to a grounded plate (78) via a second cable (55), said circuit comprising in a first path between the said first and second external connections a series combination of a first diode (D1), a first resistor (R2), a second diode (D2) followed at a first junction point (7) by a parallel combination of a second resistor (R3) with a first capacitor (C4), said circuit also comprising a series combination of second (C2) and third (C3) capacitors connected across said first resistor (R2), said second (C2) and third (C3) capacitors forming a second junction point (3), said circuit further comprising a parallel combination of a fourth capacitor (C1) and a neon-glow lamp (T1) connected between said first external connection and said second junction point (3), said circuit further comprising a third resistor (R1) connected between said first (7) and second (3) junction points.
The device according to Claim 1 further characterized in that the cage (11) is placed on a tin plate (99) that is bolted onto a column (77), said column (77) ending in three welded branches (100) which are bedded together with the end part of the said column (77) into a concrete pedestal (88), whereby crotches (121) for the storage of said first cable (44) are welded onto one side of the said column (77) and whereby a branch bolted on the other side of the said column provides the connection between the said second cable (55) and the said grounded plate (78).