Abstract:
Installation for the removal and the deactivation of organisms in the ballast water, with the following characteristic features:
       a first feed pump for conveying the ballast water,   an equipment for gravity precipitation of coarser solids and bigger organisms, connected to the first feed pump, and/or a backwashable filtration equipment,   a downstream side connected equipment for the deactivation of micro-germs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   With the ballast water, ships take up the most heterogeneous animal and vegetal organisms, e.g. mussels, fish, worms, crabs, bacteria, viruses and so on, which they set free again in extraneous regions where these are not native. These organisms often can spread rapidly in their new environment, because natural enemies are lacking. Through this, big ecological and/or economical damages can be brought about. 
   Different methods to prevent release of organisms with the water in tanks are known, e.g. by filtration, heat treatment, by reverse osmosis or UV-irradiation. Further, it is known to chemically combat organisms in water. All the stated methods are insufficient when applied to ballast water, however. The ballast water is conveyed into the ballast tanks in a very short time with a very high speed or high volume, respectively. In doing so, it must be ensured that the ballast water has been made aseptic to a large extent in this relatively short period of time. 
   The invention has the objective to create an installation for the removal and the deactivation of animal or vegetal organisms in the ballast water, which fullfills the security standards upon filling or clearance of the tanks with sparsely sumptuous means. Further, the installation according to the invention should bring about little expenditure in apparatus and should also be susceptible to be backfitted in a simple manner, e.g. on ships. 
   The installation according to the invention consists of at least two components. One of them has a gravity precipitation, e.g. a group of hydrocyclones which are parallel connected, a control equipment providing that only as much hydrocylones are in operation as is needed. As is generally known, hydrocyclones have only a restricted range of operation. That is why a control equipment switches the hydrocyclones on or off, in accordance with the conveying volume. The hydrocyclones do not only significantly reduce the sediment load carried along with the water, but they also remove a great deal of bigger organisms, in a dimension of more than 300 μm, e.g. The hydrocyclones are dimensioned such that these organisms can be efficiently separated, even when their specific weight is only faintly larger than 1. 
   A peculiarity of the hydrocyclones is that an arbitrary number can be connected together, in order to adjust them to any arbitrary quantity passing through, within the framework of their operating optimum. Hydrocyclones have also the advantage that they are almost maintenance-free and operationally reliable. They are insensitive against occlusions and can be simply and quickly attended, as the case may be. According to one form of the invention, they have a wear-resisting, corrosion-proof surface, e.g. in the form of a coating. Through this, the inner walls are protected against abrasive and corrosive strains. 
   The first feed pump is preferably a rotatory pump, as is usually in operation as a ballast water pump, e.g. 
   BRIEF SUMMARY OF THE INVENTION 
   According to a further form of the invention, the underflow of the hydrocyclones is connected to a second feed pump, to which a first regulating equipment is associated which measures the conveying volume in the underflow duct and conveys a predetermined constant volume flow, dependent on the number of switched-on hydrocyclones. This measure stabilises the operation of the hydrocyclones. The second feed pump, which is preferably a positive-displacement pump, is switchable in steps of constant conveying volume, each step being adjusted to a predetermined number of hydrocyclones which are in operation. Alternatively, it is conceivable to associate one downstream conveying pump to each underflow of at least a part of the cyclones. 
   It is also conceivable to envision another gravity precipitation, e.g. a centrifuge or the like. It is further conceivable to omit gravity precipitation and to provide a suitable filtration equipment instead. The filtration equipment has to be dimensioned such that even coarser particles can be deposited without problems. 
   According to another form of the invention, a control valve is disposed in the duct to the filtration equipment, to which a second regulating equipment is associated, which maintains a predetermined pressure in the upstream side duct by regulating the opening area of the control valve. This measure serves also for the stable operation of the hydrocyclones, which becomes particularly effective in the backwash mode of operation of the filter. As is generally known, the pressure on the filter decreases significantly during the backwash mode of operation. Anyhow, the operation of the hydrocyclones has to be maintained. 
   A filtration equipment, arranged downstream to the gravity precipitation, serves for the fine filtration and by doing so for the deposition of parts and germs with smaller dimensions, e.g. in the range of 300 μm to 50 μm. As the case may be, organisms which can not be deposited with the filtration equipment because of their geometry and extent are damaged such that they are easily amenable to a chemical or other further treatment step. Particularly advantageous is the use of a filtration equipment as has become known from DE 4312731. Each filter cartridge of a filtration equipment having several filter cartridges has a layer of overlayed elements of elastically deformable material, two neighbouring elements of which form a flowable gap, respectively. Each element has a lip on its input flow side, which is directed towards the flow with its broad front plane and is elastically displaceable and elastically deformable in the flow direction, the opening edge of which forms the gap opening, together with the opposing fixed opening edge of the neighbouring element. A particle entering in a jamming manner in the gap opening with the flow exercises an entraining force upon the opening edge of the lip, thus narrowing the gap opening. 
   In the described backwash filter, the purified liquid coming from the hydrocyclones is directed against the outlet side of a filtering surface in the backwashing mode of operation, whilst the inlet side is connected to a backwashing pump in a backwashing branch. The backwashing mode of operation is preferably initiated when the filter is gradually becoming clogged. According to one form of the invention, this case is detected by a differential pressure measurement. When the differential pressure is a predetermined value, the backwashing mode of operation is initiated via the control equipment. The above-described adjustment in the upperflow and the underflow of the cylones provides for that the backwashing mode of operation has no nocuous effects on the operation of the hydrocyclones. 
   Organisms and germs that are in the water on the outlet side of the filtration equipment are rendered innocuous by the last component of the installation according to the invention, preferably by a chemical treatment with a means which preferably has a short time of degradation and is then biologically innocuous. The addition of a chemical, preferably a mixture of organic acids, like peroxyacetic acid, hydrogen peroxide and so forth, has the advantage that is does not only exert a desinfecting action when added to the water, but also thereafter in the tank, when the water is conveyed into a tank. As long as the water is in the tank, there is no danger of ecological damage. When the chemical is rapidly degraded, the ballast water can be passed after a short time into the sea, for instance, if that is required. 
   The supply of the chemical, preferably a biocide acting in a purely oxidative way, depends on the conveying volume, according to another form of the invention. It is to be understood that other treatment possibilities are conceivable besides the chemical treatment step, additionally or alternatively, like an UV-irradiation or the like, for instance. 
   The invention provides a dosage equipment for the application of the biocide, whereat according to a further form of the invention a pump for increasing the pressure is connected between the inlet point in the outlet duct of the filtration equipment and a point of the outlet duct upstream to it, and a dosage pump feeds the biocide into the outlet duct of the pump for increasing the pressure via a nozzle. In this bypass dosage, a partial flow is taken out of the filtered water and put under increased pressure. In the injection fitting, a biocide is metered into this pressurised water. As a result of this admixture, a premixing of the biocide with water takes already place. The premixed water is introduced into the mainstream, under conversion of the pressure energy into kinetic energy. 
   According to a further form of the invention, a static mixer is downstream side connected, which provides for an intimate mixing of the microbiocide with the water that is to be treated. The described metered addition of the microbiocide takes place with very small pressure drops. Therefore it is not necessary to dimension the first feed pump such that an additional pressure drop has to be compensated. 
   The individual treatment steps have preferably a bypass, so that a flow of water is provided even at malfunction or fail of auxiliary energy, e.g. in order to be able to ensure the ship security. If e.g. the mechanical-physical treatment step fails, for instance through failure of the hydrocyclone step or the filtration equipment, then this failure can be compensated for, for instance by an automatically occurring increase of the dosage volume of the microbiocide, so that a treatment of the conveyed water is ensured in each case. 
   The installation according to the invention is planned such that it can be operated almost maintenance-free and that it ensures the highest operational reliability as possible. It is suited for new constructions and for backfitting as well. The outer dimensions of the whole installation can be geared to the room available, e.g. on ships. All components can get along with the conventional deck to ceiling height. The demand of electrical energy is relatively low. 
   The installation according to the invention is not restricted to its application to ships, but it can be also used for land-based installations, when a like or similar problem definition is present. 
   The invention is subsequently explained in more detail, by means of a realisation example represented in drawings. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  shows schematically an installation according to the invention. 
       FIG. 2  shows a hydrocyclone of the installation according to  FIG. 1  in a side view. 
       FIG. 3  shows the side view of the hydrocyclone according to  FIG. 2 , twisted at 180°. 
       FIG. 4  shows the side view of a group of hydrocylones for the installation according to  FIG. 1 . 
       FIG. 5  shows the top view of the group according to  FIG. 4 . 
       FIG. 6  shows the side view of the hydrocyclones according to  FIG. 4 . 
       FIG. 7  shows in a section the supply of the microbiocide into the outlet duct of the filtration equipment. 
       FIG. 8  shows a schematic, exploded perspective view of a static mixer of the installation according to  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   While this invention may be embodied in many different forms, there are described in detail herein a specific preferred embodiment of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiment illustrated 
   The installation according to  FIG. 1  has the steps or components A, B and C. The component A serves for the gravity separation of parts in water which are heavier than water. The component B is concerned with a fine filtration step. 
   The component C is concerned with the metered addition of a desinfectant. Subsequently, the individual components will be commented on in more detail. 
   A first feed pump  10 , preferably a rotational pump, conveys via a stop valve  12  into a duct  14 , which is in connection with six hydrocyclones  16 . 1  to  16 . 6 , via stop valves  18 . 1  to  18 . 6 . The upperflow of the hydrocyclones  16 . 1  to  16 . 6  is connected to a common duct  20 . The underflow of the hydrocyclones  16 . 1  to  16 . 6  is connected to a common duct  22  via stop valves  24 . 1  to  24 . 6 . The duct  22  is connected with a duct branch  26 , in which a pressure gauge  28 , a flow meter  30 , a second feed pump  32  as well as a stop valve  34  are situated. The function of the described parts is dwelled on below. 
   The duct  20  is connected with a duct branch  36 , in which a control valve  38  is disposed. Further, a pressure gauge  40  before the valve  38  and a flow meter  42  after the valve  38  are connected to the duct branch  36 . Additional pressure gauges  44  and  46  are disposed before and after the flow meter  42 . 
   A back-washable filtration equipment  50  is in connection with the branch  36  via a stop valve  48 . A regulating fitting  54 , a stop valve  56 , a pressure gauge  58  and a flow meter  60  are connected to an outlet duct  52  of the filtration equipment  50 . A stop valve  64  is disposed in a bypass duct  62 , which is connected before the valve  48  and after the valve  56  with the inlet and the outlet of the filtration equipment  50 , respectively. 
   In a suction duct  66 , which is connected to the filtration equipment  50 , a stop valve  68 , a backwashing pump  70 , a pressure gauge  72 , a control valve  74  and an additional stop valve  76  are disposed. 
   A branch duct  78 , which is connected to the branch outlet duct  52  immediately on the downstream side after the filtration equipment  50 , contains a stop valve  80 , a pump for increasing the pressure  82 , a check valve  84 , an injection nozzle  86  and a stop valve  88 . On the downstream side of the flow meter  60 , the branch duct  78  runs into the outlet duct  52 , via an injection nozzle  90 . On the downstream side of the injection nozzle  90 , a static mixer  92  is disposed in the duct  52 . On the downstream side of the static mixer  92 , a pressure gauge  94  is connected to the outlet duct  52 . The outlet duct  52  leads to a not shown tank, the ballast tank on a ship e.g. 
   A not shown control equipment controls the individual functions of the described parts and components, which furthermore contains a couple of control loops. Subsequently, the function of the installation according to  FIG. 1  will be explained in more detail. 
   Upon open stop valves  12  and  18 . 1  to  18 . 6  and closed stop valve  96  in a bypass duct  98  for the hydrocyclones  16 . 1  to  16 . 6 , the rotary pump  10  supplies sea water into the hydrocyclones  16 . 1  to  16 . 6 . The underflow of the hydrocyclones  16 . 1  to  16 . 6  is connected to the duct  26 , and the constant feed pump, preferably the positive displacement pump  32 , conveys a constant volume from the underflow of the cyclones into the sea. However, the number of the actually switched-on hydrocyclones  16 . 1  to  16 . 6  depends on the required conveying volume, which may also be proportional to the pressure which can be measured on the downstream side of the pump  10  with the aid of the pressure gauge  100 . When the ballast water tank is partially filled, the conveying volume enforcedly becomes smaller. As mentioned, the second feed pump  32  conveys a constant volume of water, the volume being dependent on the number of switched-on hydrocyclones  16 . 1  to  16 . 6 , however. With the number of switched-on hydrocyclones  16 . 1  to  16 . 6  becoming bigger, the constant volume of water becomes stepwise larger. The flow meter  30  serves for the regulation of the conveying volume of the pump  32 , which is predetermined by the number of cyclones in operation. It provides for that the conveying volume of the pump  32  remains constant, in dependence of the number of cyclones in operation. 
   Instead of one single second feed pump, it is also conceivable to connect a smaller pump to each underflow of a cyclone, in order to stabilise the operation of the cyclone. 
   A further control equipment is associated to the control valve  38 , which provides for a constant pressure in the duct  20 , via the pressure gauge  40 . Through the adjustment of the pressure in the duct  20  and the conveying off of the underflow in a constant volume it is provided for the hydrocyclones  16 . 1  to  16 . 6  or for the switched-on cyclones to work under stable operating conditions. 
   In the filtration equipment  50 , which is realised according to DE 4312731 e.g., organic components up to an extension of 50 μm are separated. The water, which is purified to a large extent, reaches the outlet duct  52 , into which a desinfectant or a biocide is introduced via the nozzle arrangement  90 . 
   The filtration equipment  50  is back-washable, and a differential pressure meter  102  measures the pressure on the inlet and on the outlet of the filtration equipment. When the differential pressure reaches a predetermined value, the back-wash operation mode is initiated. For this purpose, the regulation fitting  54  is set to the locking position by the control equipment. Further, the back-washing pump  70  is initiated, the stop valves  68  and  76  being open and the control valve  74  slowly opening itself. The water coming from the hydrocyclones serves for washing back the filter surfaces, and with this water, the filtrate comes back into the sea via the duct  66 . 
   The filtration equipment  50  is back-washable, and a differential pressure meter  102  measures the pressure on the inlet and on the outlet of the filtration equipment. When the differential pressure reaches a predetermined value, the back-wash operation mode is initiated. For this purpose, the regulation fitting  54  is set to the locking position by the control equipment. Further, the back-washing pump  70  is initiated, the stop valves  68  and  76  being open and the control valve  74  slowly opening itself. The water coming from the hydrocyclones serves for washing back the filter surfaces, and with this water, the filtrate comes back into the sea via the duct  86 . 
   The bypass duct  62  serves to shunt the filtration equipment  50 , if any failure should take place. Through this, it is ensured that ballast water can be pumped into the ballast tank in this case also. 
   When the stop valve  80  is opened, the pump for increasing the pressure  82  branches off purified water which comes from the outlet duct  52  of the filtration equipment  50  and presses the water into the nozzle arrangement  90 , the stop valve  80  being open. On the downstream side of the pump for increasing the pressure  82 , there is an injection nozzle  86 , which is connected to a dosage pump  106 , which on its part aspirates biocide from a biocide container  108 . In this way, a premixing of the biocide with water takes place already by the nozzle arrangement  86  and the nozzle arrangement  90 . The complete mixing of the biocide with water takes place behind the nozzle arrangement  90 , whereupon a further intense mixing takes place in the static mixer  92 , which has a very low pressure drop. The pressure for the mixing is essentially furnished by the pump for increasing the pressure  82 , so that the first feed pump  10  is not charged with this. 
   In the  FIGS. 2 and 3 , the hydrocyclone  16 . 1  is represented in more detail. It has a lower conical portion  110 , with a cone angle of approximately 10°. It is connected to an upper cylindrical portion  112 , into which sticks an inner pipe  114  from the upside, which extends downward for about half the height of the cylindrical portion  112 . A supply pipe  116  is tangentially connected to the cylindrical portion  112  in the upper region. The hydrocyclone  16 . 1  is realised such that even particles are deposited the specific weight of which is only faintly higher than that of water or sea water, respectively. 
   In the  FIGS. 4 to 6 , a battery of hydrocyclones is represented. One recognises two rows, each with three hydrocyclones. The rows are designated with  118  and  120 , respectively. They are kept in a frame  124  which can be drawn up on the deck of a ship, for instance. In centre between the rows, there is disposed a first pipe  126 , a second pipe  128  and a third pipe  130 , which are arranged one upon the other in one plane. They are in connection with the upperflow or the supply or the underflow of the cyclones, respectively. The arrangement of the cyclones is extraordinarily compact and can be accommodated fairly well, even at narrow spatial conditions. 
   In  FIG. 7 , the duct  52  is indicated, the outlet duct coming from the filtration equipment  50 . It has a lateral junction  132 , passing through which a pipe  134  is sealingly guided, which has a nozzle  136  on its upper free end and which has a nozzle-like contraction  138  outside of the duct  52 . Below the contraction  138  a lateral pipe connection  140  is provided, which is in connection with the dosage pump  106 . The lower end or the inlet  142  of the pipe  134  is in connection with the pump for increasing the pressure  82  according to  FIG. 1 . The microbiocide is brought or injected into the pipe  134 , respectively, via the connection  140  and is already intensely mixed with the water coming from the pump for increasing the pressure  142 , in the nozzle-like contraction  138  with the aid of the flow acceleration. The mixture of microbiocide and water is then injected approximately in centre into the flow in the outlet duet  52  via the nozzle arrangement  136 . After the premixing in the pipe  134 , a mixing in the outlet duct  52  takes place now, whereat a definite intense mixing occurs in the static mixer  92  which is indicated in  FIG. 8 . 
   In  FIG. 8 , the mixer is shown as consisting of two pipe halves  144 ,  146  which are centrically divided in the longside direction. In the interior of the static mixer  92 , segment-like flow disturbers  148  are disposed, which each form a V-shaped flow cross-section, the V-shaped cross-section being twisted in distances on the axis, so that the flow is twisted around its longitudinal axis. The pressure drop in such a static mixer is about 0.2 to 0.4 bar. 
   It should be noted that the hydrocyclones  16 . 1  to  16 . 6  can be provided with a wear-resisting and corrosion-proof surface, a ceramic coating for instance, which decreases the frictional resistance and forms a resistance against abrasion and corrosion. 
   It should be further mentioned that a third control equipment controls the supply of microbiocide from the container  108  into the outlet duct  52 , by measuring the volume flowing in the duct  52  by means of the volume flow measuring equipment  60 , the dosage pump  106  thereat conveying the microbiocide in accordance to the measured volume. 
   The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims. 
   Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim  1  should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below. 
   This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.