METHOD FOR SALT CASTING

Abstract: The present invention concerns a method for casting salt energy storing rods. The method is characterized by the fact that a pipe (1) fitted with a flange is enclosed in a bag/cover (3) salt-tight placed in a divided plastic cast mould (5), which is designed to absorb pressure from crystal growth at a change of phases, at which salt in a melted state is filled in around the pipe and into the bag, after which the body thus received is exposed to a lower temperature for a certain period of time, enabling a change of phases from a liquid to a solid state in the salt.

Description: Method for salt casting : Technical field: The present invention concerns a method for casting salt with energy storing rods. Background art: The principle of storing energy in salt has been known for a very long time, whereas the main problem has been to pack the salt in such a way that it has been possible to get the water in the melted salt quickly in and out of the salt. One specific problem has been to be able to absorb the pressure from the crystal growth at a change of phases from a liquid state to a solid state (when casting). Another problem is the choice of salt for the appropriate difference in temperature of high pressure side (salt) and relative low pressure side (water). The invention: The method according to this invention signifies a solution to these and other connected problems. This method is characterised in that the enclosing of a pipe fitted with a flange in a bag/cover made up of salt that is of a stopping-up kind and is placed in a divided plastic cast mould, which is designed to absorb pressure from crystal growth at a change of phases, at which salt in a melted state is filled in around the pipe and into the bag, after which the body thus received is exposed to a lower temperature for a certain period of time, enabling a change of phases from a liquid to a solid state in the salt, and that around the flanges in the pipe fitted with flanges is established a net or a perforated stripe which together with the pipe fitted with flanges is placed in the bag that stops up against salt, and the same net/stripe is established to absorb pressure from crystal growth at a change of phases liquid - solid. Therefore at this point the problem with the crystal growth at a change of phases from liquid to solid state has been solved. No moisture is removed when casting and the moisture enters the solid state when casting. The divided mould means expansion potentials at a change of phases. As a preferable alternative a stripe is utilised, and it is perforated to approximately 50% for the filling of salt in a melted state, or an enclosing net in order to generate diffusion to and from the salt, dehydrogenated or hydrogenated. As another preferable alternative a method is used by which the salt is utilised in the chemical heat pump thus received and which is characterised in that the fact that the desiccation of the water in the salt rod received is made to 100%, at which 45-50% of this water is removed at the first desiccation out of the heat pump system, and that merely 50-55% of this water is utilised in the process and that the salt does not enter into a liquid state any longer, but is constant in the crystal state. You preferably use moulds of polystyrene, and the bag to be used may preferably be made of polythene, which is impermeable to salt in a melted state. This stripe or net absorbs the pressure from the crystal growth at a change of phases from liquid to solid and may allow a certain amount of expansion. The salt in the completed rods may when being utilised be desiccated, e.g. with sun panels during the hot time of the year, and then the heat can be extracted in the winter by allowing the water to return to the salt. It is also possible to utilise waste heat from industries for the desiccation = the storage of heat. All the metallic material that is utilised according to this method should be of steel. After the desiccation, which takes place by means of transport/ flow of hot water, the packing of the received rods in a tank is carried out, which relieves the subsequent utilisation, when they are constructed together with several tanks/energy dimensioned number. The drawing: The invention is exemplified in the enclosed design. Description of embodiment: Around a convector pipe (1) fitted with convector flanges (4) a stripe (6) is placed, and this is perforated to approximately 50% or a net and this allows a certain amount of expansion at crystal growth in the salt at the change of phases. It is designed for the filling of salt in a melted state and in order to generate diffusion to and from the salt, dehydrogenated or hydrogenated. At the top a refilling funnel (7) made of plastic is established. Around the pipe fitted with flanges together with its enclosing stripe a bag of polythene is established, which is impermeable to salt in a melted state (3). This is stopped -up against the pipe at the bottom at (2). The body thus received is placed into a divided mould (5) made of polystyrene, which allows an expansion of the cast body at a change of phases to a solid state for the salt (sodium sulphide). In the space closed by the bag salt is filled in at (7) in a melted state and at the subsequent change of phases the mould (5)and even the stripe (6) allow some expansion. The temperature for the melted salt may at refilling be +40/50 degrees centigrade, and the change of phases may take place at room temperature of +20 degrees centigrade during a certain period of time. This invention can be varied in many ways within the scope of the patent requirements below.

Claims: Claims: 1. Method for casting salt with energy storing rods, characterised in that the enclosing of a pipe (1) fitted with a flange in a bag/cover (3) made up of salt that is of a stopping-up kind and is placed in a divided plastic cast mould (5), which is designed to absorb pressure from crystal growth at a change of phases, at which salt in a melted state is filled in around the pipe and into the bag, after which the body thus received is exposed to a lower temperature for a certain period of time, enabling a change of phases from a liquid to a solid state in the salt, and that around the flanges (4) in the pipe fitted with flanges is established a net or a perforated stripe (6) which together with the pipe fitted with flanges is placed in the bag that stops up against salt (3), and the same net/stripe is established to absorb pressure from crystal growth at a change of phases liquid - solid. 2. Method according to patent requirement 1, characterised in that the stripe (6) being perforated to approximately 50% for the filling of salt in a melted state in order to generate diffusion to and from the salt, dehydrogenated or hydrogenated. 3. Method according to patent requirement 1, characterised in that the net being designed as an enclosing net in order to generate diffusion to and from the salt, dehydrogenated or hydrogenated. 4. Method according to patent requirements 1-3, characterised in that the salt being made up of sodium sulphide (Na2S). 5. Method according to one or some of the previous patent requirements, at which the salt is utilised in chemical heat pump thus received, Characterised in that the desiccation of the water in the received salt rod being made to 100%, at which 45-50& of this water is removed at the first desiccation out of the heat pump system, and by the fact that merely 50-55% of this water is utilised in the process and that the salt does not transform into a liquid state any longer, but is constant in the crystal phase.

Inventors: ERIKSSON JAN, ERIKSSON, JAN
Applicants: ERIKSSON JAN, ERIKSSON, JAN
Application year: 1998
Main classification: C09K5
IPC codes: C09K5