DE2617539A1 - SEA WATER INTAKE FITTING - Google Patents

Description

Patent attorneys Dipl-Ing. H.Veickmahn, Dipl.-Phys. Dr. K. Fincke

Dipl.-Ing. R A.Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, DEN

PO Box 860 820

MÖHLSTRASSE 22, CALL NUMBER 98 39 21/22

HtM / th

Case 002340 (B)

DIAMOND SHAMROCK CORPORATION, 1100 Superior Avenue, Clevel ^; id, Ohio / USA

Seawater intake

The invention relates to a seawater intake or a seawater extraction pipe for a device in which from the sea withdrawn water (or in certain cases brackish water) is used or consumed that contains marine life that can lead to soiling, blockages and / or growth.

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Examples of seawater use surgical devices that are installed either on land or on vessels, heat exchangers, sea water for cooling purposes operate, electrochemical cells for producing chlorine and / or hypochlorite from sea water for industrial purposes or for ¹ Purification of water and water desalination devices, in which sea water is converted into fresh water. The marine life contained in the sea water can lead not only to pollution or fouling of the devices as such, but also to pollution and fouling of the pipelines, pipes, lines and the like in which the sea water is led from the sea to the device and finally, the suction grids or suction screens, which are used to prevent the penetration of particles or objects, fish and the like, contained in the sea can also become dirty or overgrown. Examples of marine life which can give rise to such pollution and to such fouling are bacterial slime, algae, bivalve mussels and in particular mussels, barnacles and especially barnacles and the like. Since the effectiveness of the operation of such devices is impaired or the operation is interrupted by the pollution and the fouling, measures have so far been sought with which the pollution and the fouling by marine life can be kept to a minimum or prevented. Examples of proposals of this type are the devices and procedures described in US Pat. Nos. 3,520,790, 3,458,413 and 3,530,051, which, despite some successes, have disadvantages which limit their application.

In particular, according to the teaching of US Pat. No. 3,520,790, which teaches the use of copper ions from in seawater heat exchangers copper anodes arranged in or pipes are released to prevent the adhesion and growth of marine life, no measures have been taken to keep the seawater inlet grille or sieve free from contamination or fouling, effective countermeasures make it necessary

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that the copper anodes would stretch to the surface of the line.

US Pat. No. 3,458,413, which proposes the use of electrodes in the inlet region of a seawater pipe (seawater tanks from Scliiffen) and the application of an electrolyzing current of 0.06 to 1 A / m ³ of the seawater flowing through the pipe every hour, gives no measures with which the penetration of particles or objects contained in the sea water can be prevented, the inlet and the line being polluted and overgrown by marine organisms up to the point of the electrodes.

Finally, in practicing the teaching of U.S. Patent No. 3,530,051 relating to a complex seawater inlet port which includes an inlet conduit screen surrounded by a number of electrode assemblies each including a central anode closely surrounded by a plurality of cathode rods is, significant investment costs and high operating costs are required because chlorine is lost to the sea because of the remote location of the electrode units with respect to the seawater inlet line. In addition, this complicated inlet opening is subject to damage by particles or objects present in the sea and must be operated at cathode current densities of at least about 3 A / dm ² if the narrow anode-cathode gap is to be prevented from blocking the narrow anode-cathode gap by mineral deposits.

In view of this prior art, the object of the invention is to provide a device that the pollution or the growth of seawater consuming or using devices (including associated Seawater transport pipelines) prevents or inhibits the disadvantages of the conventional devices of this type on a Minimum holds or eliminates, and consists in particular in a seawater intake or a seawater extraction pipe for

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to create such devices and additional lines that provides considerable protection against pollution, clogging and marine life, simply constructed and is constructed and yet stable, the particles, objects and floating debris contained in seawater, without mit'Meerwasserorganismen from becoming polluted and overgrown within a wide range of flow velocities of the sucked in sea water can be operated without clogging by mineral deposits and enables effective operation.

According to the invention, this object is achieved by means of a seawater intake connection solved the type described above, which is arranged at the sea water inlet of a line, the sea water to devices that consume or use seawater and that is identified by

a) a conduit with an inlet submerged in the sea for conveying the water to the device;

b) a metallic, corrosion-resistant, electrocatalytically active, the line inlet covering, connected as an anode- · tes grid or sieve (anode grid); and

c) a sea-immersed cathode located near the anode grid and at such a distance from the Anode grid is arranged so that clogging of the anode grid by mineral accumulating on the cathode Deposits are avoided.

The seawater suction nozzle according to the invention thus comprises a combination of

1. a corrosion-resistant, electrocatalytically active anode grid covering the line inlet, and

2. a cathode that is near the anode grid and in relation

thereafter is arranged at such a distance to the sea that any mineral Deposits from the seawater are prevented from clogging the anode grid;

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this combination with a power supply for the anode grid and the cathode is provided.

When sea water is drawn in through the inlet, an electric current is passed between the anode grid and the cathode

flow either intermittently or continuously, so that chlorine is formed on the anode grid, which is a pollution or prevents or inhibited.

Further objects, advantages and embodiments of the invention emerge from the following description in which on reference is made to the accompanying drawing.

The drawing shows

in Fig. 1 is a side sectional view of an embodiment of the seawater suction nozzle according to the invention,

in Fig. 2 is a side, partially sectioned view of a second embodiment of the invention and

in Fig. 3 is a perspective side view of a further embodiment, which is also shown partially in section is.

From the drawing, which shows three different embodiments of the seawater intake connector according to the invention, wherein for the same features the same reference numbers are chosen, it can be seen that the intake manifold is off

an anode grid 1 or a grid or screen connected as an anode, which is corrosion-resistant to seawater and whose surface is at least partially electrocatalytically active and that at the inlet end 2 of a line 3 for conveying Sea water is attached to a sea water consuming device and covers the inlet; and

a cathode 4, which is spaced from the anode grid 1 and with respect to the inlet end 2 of the line 3 in the direction of

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the sea is arranged at such a distance that clogging of the anode grid 1 by itself on the cathode 4 accumulating mineral deposits from seawater (which are believed to be predominantly magnesium hydroxide and calcium hydroxide acts) is prevented. The anode grid 1 and the cathode 4 are via the anode lead or the cathode line 7 is connected to a (not shown) direct current source.

In the seawater intake port shown in FIG. 1, whose line 3 is shown as consisting of metal, the anode grid with the help of a retaining ring 8, which consists of a Non-conductive material, such as rubber or plastic, is attached to the line 3 and electrically insulated from it. Between the anode grid 1 and the cathode 4, an effective clogging-preventing distance is provided with the aid of a L-shaped isolation ring 9 formed on the surface of the Cathode 4 is arranged and attached to the Line 3 adjoins and this is adjacent. The ring 9 also serves to electrically isolate the line 3 from the Cathode 4. If a seawater suction nozzle of this embodiment is used on an ocean-going ship, the The hull of the ship near the inlet will serve as the cathode 4.

In the case of the seawater intake port shown in FIG. 2, whose line 3 is made of a rigid, non-conductive material, such as polyvinyl chloride, glass fiber reinforced polyester or the like, is shown, the cathode 4 is attached to the line 3 at such a distance that any mineral Deposits that form on the cathode 4 cannot clog the anode grid 1.

In a similar way, in the case of the seawater intake connection shown in FIG. 3 the line as made of a rigid, non-conductive material such as plastic or the like

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Material shown consisting of. In this embodiment is the cathode 4 below the anode grid 2 and at a distance therefrom with the help of a holding rod 12, which also consists of a dimensionally stable, non-conductive material, which is attached to the line 3, arranged at such a distance, that clogging is effectively avoided.

Although the invention with reference to the three in FIGS 1, 2 and 3 illustrated embodiments, it will be apparent to those skilled in the art that the invention is not to be limited to these particular embodiments or the elements and materials used for them.

For example, the conduit can have any size and any geometric cross-sectional shape and can be arranged in any desired direction (if it is a closed conduit) and can be off any material such as plastic, metal ,. Concrete or the like, 'the only requirement being that is that the line be resistant to sea water and the electrolysis products of the anode grid and, if it is electrical is conductive, must be isolated from the anode grid. Thus, the invention can be applied to closed lines, such as pipelines, Tubes, lines or the like or used for open lines, such as trenches, channels, gutters or even channels formed in the earth when large volumes of seawater are required.

Similarly, although the invention is based on a truncated cone shaped anode grid has been described, the geometric shape of the anode grid is not critical. It is just It is necessary that it has such a geometric shape that there is a surface available for the formation of such a Sufficient amount of chlorine to provide the desired inhibition of marine pollution or fouling. The physical shape of the anode grid is also not special

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critical, provided that it has the openings which are sufficient for an essentially undisturbed water intake, which retains the undesirable particles, objects and animals contained in the sea and is stable enough to withstand the ambient conditions occurring during use. ^! Examples of porous or perforated anodes that can be used as anode grids are wire mesh screens, wire nets, expanded metal grids, perforated metal sheets, rod grids and the like, which are used either individually or in combinations of two or more grids of the same type or different types.

The material used to form the anode grid is also not particularly critical as it only requires that the material is electrically conductive, resistant to seawater corrosion and electrocatalytic. Though many Materials that meet these requirements are particularly effective as "dimensionally stable anodes" are known. A dimensionally stable anode consists of the essentially of a corrosion-resistant substrate, which is usually a valve metal (titanium, tantalum, niobium and zirconium) or a valve metal alloy, the surface of which is partially, but preferably completely covered with a electrically conductive, electrocatalytic coating made of one Platinum group metal (platinum, ruthenium, palladium, iridium, rhodium and osmium), an alloy of a platinum group metal, an oxide of a platinum group metal or mixtures thereof or a solid solution of one or more oxides is coated by platinum group metals and one or more oxides of other metals. Because of their low Coatings made from solid solutions are particularly preferred for cost, their electrochemical efficiency and their service life consist essentially of one or more platinum group metal oxides and one or more valve metal oxides and in particular coatings composed of titanium dioxide and ruthenium dioxide in a molar ratio of 1.5 to 2.5: 1. The co-

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Settlement and the methods of making dimensionally stable anodes with coatings of this type are well known and more fully described in U.S. Patents 3,632,498, 3,711,385, 3,840,443, and 3,853,739. Cheaper coatings such dimensionally stable anodes that are equally good or even

Have better operating properties and lifetimes are coatings in which up to 60 mol% of the oxide of the platinum group metal is replaced by cobalt metatitanate, as described in US Pat. No. 3,778,363, or coatings containing titanium dioxide and ruthenium dioxide in a molar ratio of 1.5 to 2.5: 1 and in which 35 to 50 mol% of the ruthenium dioxide is replaced by tin dioxide, as indicated in US Pat. No. 3,776,834. It has been found that for seawater suction nozzles which are to be used in seawater at a temperature of 15 ° C. or less, coatings of dimensionally stable anodes, which are described in US Pat. No. 3,793,164, in which iridium oxide is the predominant or only one Is a platinum group metal oxide, have longer lifetimes and are therefore preferred. Particularly preferred as coatings for dimensionally stable anodes to be used in cold water is a solid solution which contains 70.40% by weight of SnO ₂ , 7.53% by weight of antimony oxide, _{calculated as Sb 3} O ₃ , 20.76% by weight. Contains IrO ₂ and 7.31 wt% TiO ₂ . With these preferred anode grid coatings, current efficiencies of about 85% or more in relation to the formation of chlorine can be achieved, so that the energy requirements can be reduced as a result.

On the other hand, the cathode of the seawater intake connection according to the invention can be made of any electrically conductive metal or any electrically conductive metal alloy that is preferably resistant to seawater corrosion is, such as stainless steel or alloys of nickel, titanium and the like. The nickel alloy Hastelloy C-276 has proved to be particularly effective. For certain intake manifolds, however, metals or metal alloys that are found in seawater can be used are subject to corrosion, are used as cathodes, for example for seawater intake ports on ships that

have the shape shown in Fig. 1, in which the fuselage in the vicinity of the intake manifold represents the cathode and wherein the anode grid of the intake manifold is isolated from the fuselage by a non-conductive material, since in this case the

ι Section of the fuselage that serves as a cathode / cathodic against Corrosion is protected. In general, the cathode can have any size, shape and physical shape. Consequently it can be closed or porous or provided with holes and can be in the form of plates, rods, grids, sieves or the like are present. In terms of size, the cathode is preferably designed for practical reasons that the under Current standing area in contact with seawater is generally at least about 10% or more of the electrocatalytic area of the anode grid, so that the voltage necessary for the operation of the seawater intake connector is kept low can be. If low voltages are not important, smaller cathodes can also be used. If on the other hand If the intake manifold tension is to be kept to a minimum, cathodes are used which have an effective area of about 50% or more of the electrocatalytic area of the anode own.

As can be seen from the drawings and as already explained, the cathode of the seawater intake connector according to the invention is seaward at a distance from the anode grid and in the vicinity of the anode grid at such a distance that any mineral deposits from the sea water, which form on the cathode, are prevented from reaching the anode grid to clog (ie to reduce the effective suction area of the anode grid to a noticeable extent). This distance can cannot be precisely defined as it is made up of a multitude of depends on interconnected parameters, which in turn are related to the construction, the arrangement and the Method of using the seawater intake, namely parameters such as the cathode current density, the shape of the cathode, the cathode material and the presence or absence

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presence and, if present, the intensity of natural ocean currents and the effects of ebb and flow and waves. As indicated in US Pat. No. 3,530,051, mineral deposits on the cathode can be minimized by using cathode current densities of about 3 A / dm ² or more. If the cathode of the intake manifold of the present invention is sized to take advantage of this phenomenon, spacings of 1 to 2 inches can be used. On the other hand, if the cathode is sized to require low cathodic current densities, i.e., current densities of 1 A / dm ² or less than necessary to prevent clogging, distances of 30.5 cm (1 foot) or more may be necessary However, this depends on other parameters influencing the distance, as stated above. In this context it has been shown that if the cathode is arranged in relation to the anode grid in the direction of the sea - either above, next to or below - the anode grid, the accumulation of mineral deposits on the cathode is reduced to a minimum, which is evidently based on the fact that the cathode is exposed to the natural ocean currents and the action of the waves and the action of ebb and flow. It has also been shown that this arrangement of the cathode facing the sea does not make it necessary to increase the voltage for a certain maximum, despite an increase in the necessary voltage of the sea water intake, since a further conductivity path is evidently formed, which is caused by the large volume of the sea water is formed around the cathode.

When designing the intake connection, this distance can be achieved by arranging the cathode next to or below the anode grid can be reduced as there is less tendency for any mineral deposits to accumulate which may cause the Distance between the anode grid and the cathode could bridge. Another factor that contributes to lessening this The type of cathode material used can influence the distance. So seems the accumulation of mineral

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Deposits to be less on the Hastelloy C-276 alloy and on certain stainless steel alloys. When considering All of these interrelated parameters can be designed and ideally designed by the intake manifold are used, so that on the one hand only a minimum voltage is required and on the other hand the clogging of the Anode grid of the intake port is prevented by mineral deposits.

Normally, the Meerwasseransaugstutzen using a DC power source such as a battery, a rectifier or a generator is only energized when _r sea water is sucked. However, when using a cathode which is susceptible to corrosion, it may be desirable in certain cases to supply the suction port with sufficient electricity to cathodically protect the cathode, even when seawater is not being drawn in. When the intake manifold is in operation, the amount of electricity (ampere-hours) used depends on the amount of chlorine that is to be formed on the anode grid, which in turn depends on the amount of seawater sucked in, the amount contained in the seawater, to pollution and to a Marine life, the temperature of sea water, the degree of pollution and fouling inhibition, and the like will vary. Depending on these interrelated factors, the amount of electricity typically used is such that a minimum of about 0.25 parts and a maximum of about 6 parts chlorine are formed per million parts of the water entering the seawater intake. In the preferred embodiments of the invention, that is to say those embodiments in which anode grids made of dimensionally stable anodes are used, 1 g of chlorine can be released with an amount of electricity of approximately 0.85 ampere hours. For the majority of the purposes of use, the preferred amount of chlorine, which is sufficient for adequate protection against contamination and vegetation, is generally in

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the narrower range of about 1 to 4 ppm chlorine. Although these amounts of chlorine are typically formed by continuously energizes the sea water intake when the water is sucked in, it goes without saying that There are situations in which you can electrolysis of the 'sucked in Seawater is best effected by an intermittent supply of electricity during intervals that averages the deliver the amount of chlorine corresponding to the typical values described above in relation to the sucked in water.

Although the invention, for the sake of simplicity and clarity, has referred to chlorine as a means of preventing pollution ens and the growth has been explained, it is clear to the person skilled in the art that the chlorine formed on the anode grid with water reacts with the formation of hypochlorous acid and / or sodium hypochlorite, which then ultimately acts as a means for Serve to combat marine life.

From the above explanations, the drawings and the description it can be seen that the seawater suction nozzle according to the invention has the following advantages: The simplicity and the Economics of construction, robustness, ability to remove particles and objects and marine life contained in the sea to hold back without a pollution, a vegetation or if it becomes clogged by growing marine life, allowing a high level of protection against Contamination or fouling from devices that consume seawater or additional pipes that are used for the Promotion of sea water to be used by marine life, the ability that the establishment within a a wide range of seawater suction speeds can be operated without clogging by mineral Deposits occur, a high electrical efficiency and dcimit low operating costs and a long service life at the same time minimal maintenance.

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Claims (10)

Claims ■ hl sea water suction nozzle for a device in which water taken from the sea is used which contains marine life which can lead to pollution, blockages and / or growth, characterized by a) a line (3) with an inlet (2) submerged in the sea for conveying the water to the device; b) a metallic, corrosion-resistant, electrocatalytically active, the line inlet covering, connected as an anode Grid (1) (anode grid); and c) a near the anode grid, immersed in the sea cathode (4), which is at such a distance is arranged to the anode grid that clogging of the anode grid by accumulating on the cathode, mineral deposits are avoided. 2. Seawater intake connector according to claim 1, characterized in that the cathode (4) has such a size that the current density of the cathode is about 3 A / dm ² or more when the intake connector is energized. 3. Sea water intake according to claim 1, characterized in that the anode grid (1) is a Resistant to seawater corrosion, electrically conductive substrate, the surface of which at least partially with is provided with a coating consisting essentially of a valve metal oxide and an oxide of a platinum group metal consists. 603845/0772 4. Sea water intake according to claim 3, characterized characterized in that the substrate of the anode grid (1) contains a valve metal. 5. Sea water intake according to claim 3, dadurc η characterized in that the coating is substantially consists of titanium dioxide and ruthenium dioxide in a molar ratio of 1.5 to 2.5: 1. 6. sea water intake according to claim 5, characterized in that the substrate of the anode grid comprises a valve metal. 7. Sea water intake according to claim 3, characterized in that the coating consists essentially of titanium dioxide, ruthenium dioxide and tin dioxide, the molar ratio of TiO ₂ : RuO ₂ and SnO ₂ in the range from 1.5 to 2.5: 1 and the tin dioxide constitutes 35 to 50 mol% of the total amount of ruthenium dioxide and tin dioxide. 8. sea water intake according to claim 7, characterized in that the substrate of the anode grid contains a valve metal. 9. Sea water intake according to claim 3, characterized in that the coating consists essentially of a mixed oxide coating containing 30 to 90% by weight of SnO ₂ , 1.0 to 10% by weight of antimony oxide, calculated _{as Sb 2} O _3, 1.0 to 50% by weight of at least one oxide of a platinum group metal and 0.5 to 30% by weight of titanium dioxide with the proviso that the molar ratio of tin dioxide to antimony oxide is between 85:15 and 95: 5. 10. Sea water intake according to claim 9, characterized in that the oxide of a metal Platinum group iridium oxide is present and the substrate of the anode grid contains a valve metal. 609845/0772 Blank page