| Use of fluidic pumps -> Monitor Keywords |
|
|
 
Use of fluidic pumpsUse of fluidic pumps description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20080304977, Use of fluidic pumps. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION
The present invention relates to the transportation of materials, more particularly the transportation of molten materials. Most specifically, the invention is concerned with the transportation of materials in the molten state, and provides a simple, dependable method for this purpose. BACKGROUND TO THE INVENTIONThere is a frequent requirement in industry for the use of molten materials, both as solvents and as reaction media. Naturally, there are occasions when the use of such materials requires the use of a plurality of vessels and, therefore, necessitates the transportation of the materials between locations. Technically, this can cause problems, since it is generally the case that elevated temperatures have to be maintained throughout the operations which are being performed, in order that the molten materials remain in a molten state. Thus, it is necessary that methods of transportation which are employed should not at any point give rise to a fall in temperature which might lead to solidification of the material. Furthermore, it is often the case that chemical reactions are required to be carried out in an inert atmosphere from which air—more specifically, the moisture associated with the atmosphere—are excluded, in order that unwanted side reactions and hydrolysis may be avoided which, in extreme circumstances, may completely prevent a desired reaction from being achieved. In addition, moisture-sensitive components have to be protected from contact with the atmosphere at all times in order that problems associated with hydrolysis and/or degradation may be avoided. Such difficulties are frequently encountered on a laboratory scale, but may be fairly easily overcome in such circumstances by the provision of an inert blanket of, typically, nitrogen gas using standard laboratory procedures. When moisture-sensitive materials require to be handled on a commercial scale, however, the potential difficulties are exacerbated, and carefully devised procedures have to be implemented in order that serious problems do not occur. This is particularly true when such materials have to be transported though industrial scale apparatus and plant machinery, where damage to the apparatus could occur, as well as loss of the material. In this context, the present inventors have specifically addressed the difficulties which are associated with the handling of so-called molten salts on a plant scale. These materials find widespread use, for example, in the reprocessing/waste conditioning of irradiated nuclear fuel by means of the Argonne National Laboratory electrometallurgical treatment process (ANL—EMT) and the Dimitrovgrad SSC—RIAR process, which both use molten salts at high temperatures (773 and 1000 K, respectively). Molten salts have also been proposed for use in the reprocessing of irradiated fuels from Light Water Reactors (LWRs). A further major interest in molten salts has centred on their potential use in molten salt reactors, which would produce electricity, as well as burning actinides and long-lived fission products. These molten salts are typically mixtures of salts which are liquid only at high temperatures. Traditionally molten salts melt above 150° C., and more frequently at much higher temperatures than this, and such salts are usually composed of inorganic cations. Thus, it can be seen from a consideration of the prior art that the use of molten salts in industrial applications is widespread, and there is frequently a requirement for the handling and transportation of such materials on an industrial scale. Specific examples of the requirement for the handling of molten salts include the transfer of molten salts with a pump, most particularly a centrifugal pump, at solar power stations, wherein a mixture comprising sodium and potassium hydroxides and nitrites, melting at 146° C., is typically employed, and wherein there is a requirement for the molten salt to be handled at temperatures of up to 500° C. Alternatively, simple mixtures of sodium and potassium hydroxides, melting at 225° C. and showing increased stability at higher temperatures, may be utilised. It will be apparent, therefore, that there are certain key requirements for the satisfactory handling of molten salts in industrial applications. Primarily, of course, it is necessary that there should be provided a heating system capable of heating and melting salts above the melting point of the salts, and desirably at a suitably higher temperature, preferably in the range of 500° to 550° C., so to make the melt less viscous. Furthermore, the apparatus should incorporate suitable insulation around vessels and pipes, to reduce heat losses and to ensure that no cold spot develops, which could result in freezing of the salts. In the event that some freezing of the molten salt does occur, however, it is essential that the apparatus should be able to withstand a subsequent re-melting operation without suffering damage, and it is important that the design of the apparatus should take such considerations into account. It is also generally found that the volume of salts increases by 20% when changing from the solid to the molten state, so that a zoned heating system is essential to prevent bursting of pipes or vessel deformation during melting of the salts. As an alternative to the zoned-heating of vessels to avoid deformation, it is possible to provide vessels having modified designs, such as conical vessels, although this is inevitably a more expensive option. In view of the hygroscopic nature of molten salts, it is also vital to ensure that a dry environment exists in order to prevent the salts from absorbing moisture, since this would lead to the release of hydrogen chloride gas and, as a consequence, would promote very rapid corrosion of the rig, especially at high temperatures. Thus, it is essential that an inert atmosphere is provided within the apparatus and, hence, an inerting system, preferably using an inert gas or a mixture of inert gases, is incorporated in the apparatus. Typically, said inert gas comprises argon, especially in nuclear applications where uranium metal is being handled, since nitrogen has the potential to react with uranium metal to form uranium nitride. Desirably, a system for the handling of molten salts should also be adapted to incorporate various other additional features which would facilitate the safe and efficient handling of the said materials. Included among these features would be the following:
pressure and vacuum relief system;
gas analyser to detect concentrations of O2 and H2O in the ppm range, in order to monitor the quality of the inerting system;
corrosion-resistant and heat resistant metallic parts;
heat-resistant gaskets, for example graphite-containing gaskets;
design which accounts for the dilation of pipe with temperature, for example by the insertion of sections of bent pipes in order to minimise stresses on pipes and prevent damage or rupture; and
supervisory control and data acquisition system (SCADA) to provide interlocks, thereby preventing maloperation and ensuring sequenced heating—thus, for example, preventing a user from activating any pump if the salts temperatures in various places in the rig are not above a given threshold value, i.e. above the melting point temperature, or ensuring that the correct heating sequence is adhered to by eliminating the possibility that, for example, a bottom wrap might be heated as the first step.
Thank you for viewing the Use of fluidic pumps patent info. IP-related news and info Results in 0.07893 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
How KEYWORD MONITOR works... a FREE service from FreshPatents