Abstract:
A fluid conducting system with cathodic corrosion protection is provided for at least one device that influences and/or acts upon a flow rate, such as a pump and/or valve. The device includes at least one connection device such as a device connection flange. At least one flow rate guiding device such as a pipe includes a connection means such as a pipe connection flange. The system includes annular anodes arranged between the connection devices and connection means, where anodes are electrically connected by electrical conducting lines to a monitoring device. The internal diameter of the anodes is preferably equal to the internal diameter of the flow rate guiding device and/or the inner diameter of the inlet and/or outlet of flow influencing device.

Description:
[0001]    This application is a national stage of PCT International Application No. PCT/DE2014/062857, filed Jun. 18, 2014, which claims priority to German patent application: DE 10 2013 212 725.1, filed Jun. 28, 2013 in the German Patent Office, the disclosures of which are herein incorporated by reference in their entirety. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    The invention relates to a fluid-conducting system with cathodic corrosion protection, having at least one device conveying and/or influencing a flow rate, in particular a pump and/or valve having at least one connection device, and having at least one device guiding a flow rate, in particular a pipe element, having connection means. 
         [0003]    Fluid-conducting systems of this type having pumps or valves are widespread and are often used to convey and influence corrosive fluids or media, whereby the inner walls exposed to the fluid or medium sustain damage and parts of the system or of the devices have to be replaced after a certain time. 
         [0004]    In order to protect pumps or valves against corrosion, it is known for example from South Korean patent document KR 100540390 B1 to attach a bolt connecting the casing of an valve to a water pipe to a sacrificial anode. 
         [0005]    Pumps are also known that have sacrificial anodes arranged inside the casing. Examples for this include Japanese patent documents JP 2002295389 A, JP 2002295390 A or JP 2002242874 A. 
         [0006]    The disadvantage with both variants lies in the fact that recurring maintenance works have to be performed and, in particular with internal sacrificial anodes, the entire system has to be switched off. 
         [0007]    German utility patent document no. DE 7603732 U discloses a water container in the lower region of which an electric heating element is arranged. A passive anti-corrosion layer made of enamel is formed on the inner wall of the container. Furthermore, electrodes supplied with external current and providing cathodic corrosion protection are provided, wherein the electrodes can be set to an optimal potential by means of a potentiostat and a reference electrode, and at least one external current anode is arranged in the vicinity of the heating element. An arrangement of this type, however, has proven to be unsuitable for systems having a relatively high flow. 
         [0008]    The object of the invention is to provide a fluid-conducting system or a device conveying or influencing a flow rate, having a cathodic corrosion protection system, in which the above-mentioned disadvantages are overcome, without disturbing the flow rate in the device or a pipe system connected thereto. 
         [0009]    The object is achieved in accordance with the invention in that the fluid-conducting system comprises annular anodes, wherein an anode is arranged in each case between a first and a second connection device and/or between a first connection device and a connection means and/or between a second connection device and a connection means, the anodes are electrically connected to a monitoring arrangement by means of lines comprising one or more conductors, and the inner diameter of the anodes is equal to the inner diameter of the device guiding a flow rate and arranged on the respective anode. 
         [0010]    According to the invention, in a further embodiment, the inner diameter of the anodes also corresponds to the inner diameter of the inflow or outflow opening, assigned to the respective anode, of the device conveying or influencing a flow rate. Turbulences and/or flow vortices in the fluid-conducting system are thus prevented. 
         [0011]    In a further embodiment one or more threaded bores are provided in the casing, into which bores reference electrodes electrically conductively connected to the casing are screwed. It is thus possible to bring the reference electrodes into contact with the fluid or the flow rate within the casing without said electrodes protruding into the casing or without a dead space forming, i.e. a blind hole-like indentation. At the same time, this opening in the casing can be easily sealed. 
         [0012]    The fact that the reference electrodes are arranged relative to one another in such a way that the greatest possible inner surface of the casing can be balanced in terms of the potential enables the system to be reliably operated. A state monitoring of all surfaces within the casing contacted by a medium or fluid is thus reliably ensured. 
         [0013]    In accordance with a further embodiment, in order to optimize the operation, the monitoring arrangement comprises a control or regulation unit, a first rectifier, a second rectifier and a measuring module. 
         [0014]    It is proposed in accordance with the invention for an annular and electrically insulating first insulation washer to be arranged between the anode and the first or the second connection device and also for an electrically insulating second insulation washer to be arranged between the anode and the connection means. It is thus possible to compensate for varying distances between the casing of the pump or the valve using insulation washers of different thickness or by using a number of insulation washers. 
         [0015]    In order to ensure reliable insulation protection, bores are provided in accordance with the invention in the first and/or second connection device and in the connection device of the pipe elements, there being electrically insulating insulation sleeves arranged in said bores. These are preferably inserted into the bores for simple assembly. 
         [0016]    In order to increase the insulation protection, the insulation sleeves at their free end have a collar. 
         [0017]    The invention is also achieved by a device conveying or influencing a flow rate, in particular a pump arrangement or valve arrangement for a fluid-conducting system with cathodic corrosion protection. 
         [0018]    Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows the side view of a horizontally divided spiral casing pump attached to a pipe system and connected to a control and monitoring device in accordance with an embodiment of the present invention, 
           [0020]      FIG. 2  shows a schematic diagram of a monitoring arrangement in accordance with an embodiment of the present invention, 
           [0021]      FIG. 3  shows a sectional view of an valve attached to a pipe system in accordance with an embodiment of the present invention, and 
           [0022]      FIG. 4  shows a detailed section view of the connection region of the spiral casing pump and of the pipe system in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    A device  1  conveying a flow rate is illustrated in  FIG. 1 , said device being in the form of a horizontally divided spiral casing pump for a fluid-conducting system, wherein the device  1  conveying a flow rate comprises a casing  2  having an inlet connection piece  3  and an inflow opening  4  and an outlet connection piece  5  having an outflow opening  6 . A first connection device  7  is formed at the inflow opening  4  and a second connection device  8  is formed at the outflow opening  6 , in each case in the form of a flange. Whereas the first connection device  7  is attached to a connection means  9 , for example a connection flange, of a pipe element  10 , the second connection device  8  of the device  1  conveying a flow rate is attached to a connection device  11  of a pipe element  12 . 
         [0024]    An annular first anode  13  formed as an external current anode and insulated with respect to the connection device  7  and the connection means  9  is arranged between the first connection device  7  of the device  1  conveying a flow rate and the connection means  9  of the pipe element  10 . An annular second anode  14  formed as an external current anode and insulated with respect to the connection devices  8  and the connection means  11  is arranged between the second connection device  8  of the device  1  conveying a flow rate and the connection means  11  of the pipe element  12 . The inner diameter d A  of the anodes  13  and  14 , as shown in detail in  FIG. 4 , corresponds to the inner diameter d R  of the pipe elements  10  and  12  assigned to the anodes  13  and  14  respectively and corresponds to the inner diameters d v  of the inflow or outflow opening, arranged on the anodes  13  and  14 , of the device  1  conveying a flow rate. The anodes  13  and  14  therefore do not protrude into the flow path of the flow rate and also do not form any ‘dead spaces’, i.e. indentations, for example annular groove-like indentations, in which turbulences may occur. The anodes  13  and  14 , which are produced substantially from a titanium alloy, are coated at the region contacting the fluid or the flow rate with a substrate  15 , as illustrated in  FIG. 4 , formed from a mixture of different metal oxides, for example iridium, tantalum and/or ruthenium. 
         [0025]    A threaded bore (not illustrated) is provided on the inlet connection piece  3 , there being a first reference electrode  16  screwed into said bore. The outlet connection piece  5  also comprises a threaded bore (not illustrated), into which a second reference electrode  17  is screwed. A third reference electrode  18  is screwed on the upper side of the casing  2  into a further threaded bore (not shown). First, second and third reference electrodes are electrically conductively connected to the casing  2 , screwed into the bores. The reference electrodes, which are preferably produced from pure zinc, silver or a silver alloy, come directly into contact with the fluid or flow rate within the casing  2  without protruding into the casing interior or forming a dead space, i.e. a blind hole-like indentation. In the case of the spiral casing pump  1  shown in  FIG. 1 , three reference electrodes are preferably used, however the number of reference electrodes can be increased or reduced as necessary, in particular with different casing forms. 
         [0026]    The reference electrodes  16 ,  17  and  18  are preferably arranged relative to one another such that they can balance the greatest possible inner surface of the casing in terms of the potential. In  FIG. 1  a monitoring arrangement  19  is also shown, which for example is accommodated in a switch cabinet. The monitoring arrangement  19  has a control or regulation unit  20 , a first rectifier  21 , a second rectifier  22  and a measuring module  23 , as shown in greater detail in  FIG. 2 . A line  24  comprising one or more conductors leads from the first rectifier  21  to the first anode  13 . The second rectifier  22  is connected to the second anode  14  via a line  25  comprising one or more conductors. The casing  2  is attached both to the first rectifier  21  and to the second rectifier  22  via a line  26  comprising one or more conductors. The measuring module  23  is attached to the first reference electrode  16  by means of a line  27  comprising one or more conductors and is connected to the third reference electrode  18  via a line  28  comprising one or more conductors. A line  29  comprising one or more conductors leads to the second reference electrode  17 . A line  30  comprising one or more conductors can be guided to further, external input/output devices, measuring and/or monitoring arrangements, or computers (not illustrated). 
         [0027]    The monitoring arrangement  19  is also supplied with electrical energy from a conventional AC voltage source via a supply line  31 . The monitoring arrangement  19  is preferably additionally attached to an alarm bus line  32 . 
         [0028]      FIG. 3  shows a device  101  influencing a flow rate in the form of an valve, in particular a gate valve, for a fluid-conducting system. The device  101  influencing a flow rate comprises a casing  102  having an inlet connection piece  103  and an inflow opening  104  and an outlet connection piece  105  having an outflow opening  106 . A first connection device  107  is formed at the inflow opening  104  and a second connection device  108  is formed at the outflow opening  106 , in each case in the form of a flange. The first connection device  107  is attached to a connection means  109  of a pipe element  110 , and the second connection device  108  of the device  101  influencing a flow rate is attached to a connection means  111  of a pipe element  112 . 
         [0029]    An annular first anode  113  insulated with respect to the connection device  107  and the connection means  109  is arranged between the first connection device  107  of the device  101  influencing a flow rate and the connection means  109  of the pipe element  110 . An annular second anode  114  insulated with respect to the connection device  108  and the connection means  111  is arranged between the second connection device  108  of the valve  101  and the connection means  111  of the pipe element  112 . The inner diameter d A  of the anodes  113  and  114  corresponds substantially to the inner diameter d R  of the pipe elements  110  and  112  and to the inner diameter d v  of the inflow or outflow opening  104  and  106  respectively. The structure of the anodes corresponds to the structure described with reference to  FIG. 1 . 
         [0030]    A first reference electrode  116  is screwed into a threaded bore at the inlet connection piece  103 . A second reference electrode  117  is screwed into a threaded bore in the outlet connection piece  105 . As necessary, a third reference electrode  118  can be screwed into a further threaded bore in the upper part of the casing  102 . First, second and third reference electrodes are screwed into the bores and in so doing are electrically conductively connected to the casing  102 . The reference electrodes come directly into contact with the fluid inside the casing  2  without protruding into the valve interior or without forming a dead space. 
         [0031]    The attachment of the casing  102 , the reference electrodes  116 ,  117  and  118  and of the anodes  113  and  114  to a monitoring unit (not illustrated here) is performed in accordance with the circuit examples shown in  FIG. 1  and  FIG. 2 . 
         [0032]      FIG. 4  shows the detailed illustration of the outlet connection piece  5  of the device  1  conveying a flow rate, with the pipe element  12 . The second anode  14  is arranged between the second connection device  8  of the device  1  conveying a flow rate and the connection device  11  of the pipe element  12 . An annular and electrically insulating first insulation washer  33  is arranged between the second anode  14  and the second connection device  8  of the device  1  conveying a flow rate. An annular and electrically insulating second insulation washer  34  is arranged between the second anode  14  and the connection device  11  of the pipe element  12 . The inner diameter (not designated in greater detail in the figures) of the insulation washers corresponds to the inner diameters d A  of the anodes and the inner diameters of the inflow or outflow openings of the device  1  conveying a flow rate. Bores  35  are provided in the second connection device  8 , and bores  36  are provided in the connection device  11 . Electrically insulating insulation sleeves  37  are inserted into the bores  35  and  36 . The insulation sleeves can be formed in one or more parts and where appropriate may have at their free end a collar  38 , on which a screw head or a screw nut (not illustrated) come into abutment. Electrically insulating separate washers can also be used optionally. This arrangement of external current anode, insulation washers and insulation sleeves is also provided for the inlet connection piece of the device  1  conveying a flow rate and for inlet and outlet connection pieces of the device  101  influencing a flow rate. 
         [0033]    In the monitoring arrangement  19  shown in  FIGS. 1 and 2  the direct current required for the cathodic protection is generated and is guided via the line  24  from the first rectified  21  to the anode  13  and from the second rectifier  22  via the line  25  to the second anode  14 . The purpose of the monitoring arrangement  19  lies primarily in balancing the signals sent via the reference electrodes  16 ,  17  and  18  in terms of the potential within the pump casing with the preset limit values and, where appropriate, in adapting these via the direct current guided across the anodes  13  and  14 . This is true equally also for the device  101  influencing a flow rate illustrated in  FIG. 3  and having the anodes  113  and  114  and the reference electrodes  116 ,  117  and  118 . 
         [0034]    The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 
       LIST OF REFERENCE SIGNS 
       [0000]    
       
           1  device conveying a flow rate 
           2  pump casing 
           3  inlet connection piece 
           4  inflow opening 
           5  outlet connection piece 
           6  outflow opening 
           7  first connection device 
           8  second connection device 
           9  connection means 
           10  pipe element 
           11  connection means 
           12  pipe element 
           13  first anode 
           14  second anode 
           15  substrate 
           16  first reference electrode 
           17  second reference electrode 
           18  third reference electrode 
           19  monitoring arrangement 
           20  control or regulation unit 
           21  first rectifier 
           22  second rectifier 
           23  measuring module 
           24  line 
           25  line 
           26  line 
           27  line 
           28  line 
           29  line 
           30  line 
           31  supply line 
           32  alarm bus line 
           33  first insulation washer 
           34  second insulation washer 
           35  bore 
           36  bore 
           37  insulation sleeve 
           38  collar 
           101  device influencing a flow rate 
           102  casing 
           103  inlet connection piece 
           104  inflow opening 
           105  outlet connection piece 
           106  outflow opening 
           107  first connection device 
           108  second connection device 
           109  connection device 
           110  pipe element 
           111  connection device 
           112  pipe element 
           113  first anode 
           114  second anode 
           115  substrate 
           116  first reference electrode 
           117  second reference electrode 
           118  third reference electrode