Electric induction steam generator

Abstract

The invention relates to devices for converting electrical energy into heat and for bringing about heat transfer. The essence of the invention is that an electric induction steam generator consists of at least one steam generating assembly in the form of an outer closed loop formed of a metal pipe having a cavity therein for a heat transfer fluid and further having suspended therein an inner closed heating loop which is formed of a metal rail or is in the form of a split and slightly opened pipe, wherein the outer closed loop has at least one toroidal transformer mounted thereon, the inner hole of which allows the passage through the toroidal transformer of the metal pipe of the outer closed loop, inside which the inner closed heating loop is disposed, the bottom part of the outer closed loop is connected to a system for supplying water from a feed tank.

Description

[0001] Electric induction steam generator

[0002] The invention relates to devices for converting electrical energy into thermal energy and creating heat exchange.

[0003] Various electric steam generators are known from the prior art.

[0004] For example, an electric steam generator is known under Russian Patent No. 171694, priority dated February 15, 2016, for a utility model entitled "Electric Steam Heater" (MIK H05B 6 / 10). This electric steam generator comprises a power unit for steam generation of an induction steam generator with a secondary winding, a power unit for steam superheating of an induction superheater with a secondary winding, a ferromagnetic core with a primary winding connected to the network, secondary windings of the steam generator and superheater located on the said ferromagnetic core, the secondary windings of the induction steam generator and induction superheater are designed as a tubular conductor with inlet and outlet pipes for passing water through the internal cavity of the inner conductor, the conductive surface of which is designed as a closed one-sided Möbius surface. The disadvantage of this device is the bulkiness of the design and the subsequent complexity of the control units.The specific nature of the liquid flow in this device requires monitoring the temperature and steam pressure at the outlet, as well as the closed-loop temperature in each power unit. Furthermore, the device is connected to the power grid using a single-phase connection, which is dictated by the design of the tubular secondary winding, which has a single-sided conductive surface. As power increases, a single-phase connection dramatically reduces the device's efficiency and creates inconveniences when operating the power grid.

[0005] An electric steam generator is also known under Russian patent No. 2658658, priority dated 08 / 24 / 2017 for invention (IPC H05B 6 / 10).This electric steam generator comprises a flat ferromagnetic core with rods designed to create a closed magnetic field within them, primary windings arranged as coils on the rods and electrically insulated from them, a common tubular secondary winding located in the magnetic field insulated and encircling all rods of the ferromagnetic core such that one or more closed turns are formed around each rod, arranged alternately in the intercoil space above one another and electrically permanently connected externally in parallel in the plane of the pipe diameter, parallel to the magnetic induction vector of the rod. One or more spacer cylindrical elements are installed on the periphery in the intertube space between the turns, externally connected to the turns by a permanent connection in the plane of the pipe diameters, parallel to the magnetic induction vector of the rods. The device may be designed as a three-phase device.

[0006] The closest analogue (prototype) of the claimed invention is an electric steam generator according to Russian patent No. 2736270, priority dated 06.07.2020 for an invention entitled “Electric superheater” (IPC H05B 6 / 10). This electric steam generator includes a flat ferromagnetic core with rods designed to create a closed magnetic field in them, primary windings in the form of coils located on the rods and electrically insulated from them, a tubular secondary winding having inlet and outlet pipes, located in the magnetic field insulated and covering all the rods of the ferromagnetic core so that around each rod one or more closed turns are formed, located in the intercoil space and electrically connected in parallel inseparably externally by a shunt parallel to the magnetic induction vector of the rods, and on the periphery between the turns one or more remote cylindrical elements are installed,Externally permanently connected to the turns by a shunt parallel to the magnetic induction vector of the rods, the tubular secondary winding consists of an internal working tube and is constructed of multilayered metals such that, starting with the internal working tube, each subsequent layer completely encloses the previous one, and the contact surface of the metals of the internal working tube and each layer ensures partial mutual dissolution of the boundary metals. A distinctive feature of this steam generator is that the means for forced fluid supply are designed to control the amount of fluid supplied to the internal cavity of the tubular secondary winding depending on the surface temperature of the tubular secondary winding.and a mechanical safety valve is installed on the outlet pipe. In essence, the electric steam generator according to Russian patent No. 2658658 is an improved model of the steam generator according to Russian patent No. 2736270. The disadvantage of the specified analog and prototype is that they are made straight-through. In straight-through steam generators, the feedwater flow rate has a direct impact on the volume, temperature and pressure of steam at the outlet of the steam generator (see the book by A.P. Kovalev "Steam Generators", Moscow, 1985, p. 226). As a result, the feedwater supply to the steam generator is used as a universal parameter for controlling steam production, provided that the steam pipe in which the conversion of water into steam occurs operates stably, with high efficiency and at its maximum heating power. It should be noted that steam formation in an induction steam generator is facilitated by an electromagnetic process,excited in the internal cavity of the tubular secondary winding when a large induction alternating current flows along its cylindrical surface. When alternating current flows along the surface, high-frequency electromagnetic radiation with a critical wavelength equal to twice the diameter of the cylindrical internal cavity of the conductor cylinder arises in the internal cavity of the cylindrical conductor, which does not extend beyond the internal cavity (see the book by G.S. Kromin and E.A. Katkov "Fundamentals of Radar Technology", Part 1, Moscow, 1956, pp. 338, 346). As we have experimentally established, this radiation is mainly responsible for the accelerated dissociation of water molecules due to an increase in the amplitude of their vibrations under conditions of increasing heating temperature of the tubular secondary winding of the induction steam generator. According to existing concepts, this electromagnetic radiation is not dissipated anywhere from the internal cavity of the conductor, and part of the reactive energy in our case,is spent on separating water molecules excited by thermal energy during its phase transition to a vapor state. Thus, maximum efficiency of the vaporization process in the internal cavity of the tubular secondary winding can be achieved by maintaining the maximum possible intensity of the electromagnetic process excited in the internal cavity by the alternating current flowing along the outer surface of the tubular conductor, which leads to increased efficiency of the steam generator. Another disadvantage of this analog is its insufficient use of the advantages of the induction method for generating steam from water in the tubular secondary winding of a straight-through electric steam generator.

[0007] The objective of the claimed invention is to create a reliable electric induction steam generator with increased steam productivity while eliminating the shortcomings of flow-through electric steam generators. The technical result of the claimed invention is improved operational reliability, increased steam production, and expanded functionality. This technical result is achieved through a combination of essential features.

[0008] The essence of the invention is that the electric induction steam generator consists of at least one steam generation unit, which is an external closed loop made of a metal pipe, inside of which a cavity for the coolant is formed and an internal heating closed loop is suspended from a metal busbar or in the form of a cut and slightly spaced pipe, while at least one toroidal transformer is installed on the external closed loop, and its internal opening allows the metal pipe of the external closed loop to pass through the toroidal transformer, inside which the internal heating closed loop is located, the lower part of the external closed loop is connected to the water supply system from the feed tank, and the upper part with a branch for removing boiling water with steam into a steam evaporator connected to a steam separator, the steam separator in the lower part is made with an opening for discharging condensate into a water collector,and in the upper part there is a discharge pipe for the discharge of purified steam, and the steam separator inside is divided from bottom to top by alternating partitions, and the water supply system is made with a blowdown pipe and is connected to a water manifold and through a check valve with a high-pressure pump, the water manifold is designed with the ability to maintain the water level inside it above the internal heating closed loop and is made with water level sensors with the help of which the required water level in the steam evaporator is maintained, also the water manifold is connected to the steam separator to form communicating vessels,The high-pressure pump is connected to the feed tank. The outer closed loop is positioned vertically and is made of a metal with high internal resistance relative to the inner heating loop. The inner closed loop is designed as a cut and slightly spaced tube. The inner closed loop is also made of copper, brass, or their alloys. The toroidal transformer is designed with low inrush currents, with the primary windings wound on a toroidal core and insulated from it. Furthermore, the toroidal transformer is mounted on vertical and / or horizontal pipes of the outer closed loop. The lower part of the outer closed loop is connected to the water supply system via a coupling. To increase the evaporation area of ​​the boiling water, the steam evaporator is horizontally oriented. Furthermore,The steam evaporator is connected to a water supply system to ensure the drainage of excess condensate. Steam pressure and temperature sensors are installed in the upper part of the steam separator to monitor steam parameters, as well as a mechanical emergency relief valve designed to protect the steam generator from excess pressure. Moreover, the feed tank is equipped with a water level sensor and an electromagnetic valve to ensure the automatic maintenance of the water level. At least one heat exchanger for cooling the return condensate is designed in the feed tank. The feed tank also has an inlet for condensate return, a water drain, and an overflow for the feed tank. A method of generating steam, including feeding water into an external closed metal coil of a steam generation unit with an internal closed heating metal coil designed to heat and evaporate water to produce saturated steam,directing boiling water into a steam evaporator to increase the evaporation surface, and then into a steam separator, where the steam is purified from condensate, then the purified steam is supplied to the consumer, and the condensate is returned to the steam generation unit through a water collector, and in the steam generation unit the feed water level is automatically ensured to be higher than the level of the internal closed heating coil, which allows the water to remain in the magnetic field for the longest possible time.

[0009] The invention is explained graphically, where: Fig. 1 schematically shows a steam generation unit with three toroidal transformers; Fig. 2 schematically shows a diagram of an electric induction steam generator with three steam generation units.

[0010] The electric induction steam generator consists of at least one steam generation unit, which is an external closed coil 1 made of a metal pipe, in which an internal closed heating coil 2 is suspended, wherein at least one toroidal transformer 3 is mounted on the external closed coil 1. The external closed coil 1 is positioned vertically and is made of a metal with a high internal resistance relative to the internal closed heating coil. The external closed coil 1 forms a cavity for the coolant. An internal closed heating coil 2 made of a metal busbar is suspended inside the external closed coil 1. The internal closed heating coil 2 is made of copper or brass, or their alloys. The internal closed heating coil 2 is made in the form of a cut and slightly spaced copper pipe. This design of the closed coil made of copper busbar 2 increases the surface of contact of the coil with the water.Internal closed heating coil 2 is a heater carrying a current of 4,500 amperes or more, creating a strong magnetic field around the conductor, which also influences the water evaporation process. Toroidal transformer 3 is designed with low inrush currents; the primary windings are wound on a toroidal core and insulated from it. Toroidal transformer 3 is designed such that its internal opening allows the pipe of external closed coil 1 to pass through it. The required power of the steam generation units, consisting of external closed coil 1 and internal closed heating coil 2, is achieved by increasing the number of toroidal transformers 3. Toroidal transformer 3 can be installed on both vertical and horizontal pipes of external closed coil 1. A coupling 4 is located at the bottom of external closed coil 1, and a tap 5 is located at the top.The coupling sleeve 4 connects the outer closed loop 1 with the water supply system 12 from the feed tank 6. The branch 5 is intended for the discharge of boiling water with steam into the steam evaporator 7. In order to increase the evaporation area of ​​boiling water, the steam evaporator 7 is made horizontal and is connected to the branch 5 and to the steam separator 8. In a specific embodiment, the steam evaporator 7 is additionally connected to the water supply system 12, this connection ensures the outflow of excess boiling water from the steam evaporator 7. The steam separator 8 in its lower part is made with an opening 9 for discharging condensate into the water collector 10. The steam separator 8 is divided inside from bottom to top by partitions 19. The partitions 19 are intended for cleaning the produced steam from condensate. The steam, passing through the partitions 19 of the separator 8, is cleaned of residual moisture, which is returned through the opening 9 to the water collector 10.For removing purified steam from the steam generator to the steam load, a discharge branch pipe 11 is provided in the upper part of the steam separator 8. On the steam separator 8, in its upper part, pressure sensors 20 and temperature sensors 21 of steam are installed, intended for monitoring the parameters of steam, as well as a mechanical emergency blast safety valve 22 for protecting the steam generator from excess pressure. The water supply system 12 is connected to the coupling 4, to the water collector 10 and through the check valve 23 to the pump 13. The water supply system 12 is made with a blowdown branch pipe 18. The water collector 10 is designed above the internal heating closed loop 2 and has water level sensors 24. Thus, forced feedwater supply is not required, the water collector 10 is designed with the possibility of maintaining the water level inside it above the internal heating closed loop 2. The water level is maintained by means of the high-pressure pump 13.The water level in the water collector 10 is controlled by water level sensors 24. The water collector 10 is connected to the steam separator 8 to form communicating vessels for maintaining the water level. The pump 13 is connected to the feed tank 6. The proposed design with a closed loop 1 makes it possible to organize the "Purge" mode, i.e., cleaning the electric induction steam generator from salts, scale and dirt, which reduces the requirements for feed water. The feed tank 6 is designed to supply water to the electric induction steam generator. The water level in the feed tank 6 is maintained automatically by the water level sensor 25, through the electromagnetic valve 26. In the feed tank 6, at least one heat exchanger 14 is provided for cooling the return condensate, an inlet for condensate return 15, a water drain 16 and an overflow of the feed tank 17.

[0011] The electric steam generator operates automatically as follows. Initially, feedwater is supplied from the feedwater treatment system to feed tank 6. After feed tank 6 is filled with water, pump 13 is started and supplies water under pressure through check valve 23 into water supply system 12, into the cavity of the outer closed loop 1, and into water collector 11. When the upper water level in water collector 10 is reached, the electric induction steam generator is activated. The electric induction steam generator is equipped with additional protection against electric shock. Power is supplied to the power racks only after the "START" button is pressed and the entire system is filled with feedwater through the power rack contactors. Power is supplied to the steam generation units through fuses and triac assemblies. The activation of the steam generation units is controlled by current transformers.The water level in water collector 10 is then maintained automatically. No forced feedwater supply is required; the water level in water collector 10 of the electric steam generator is maintained by high-pressure pump 13, which maintains the required feedwater level above the internal closed heating loop 2. To ensure normal operation of pump 13, the feedwater temperature must not exceed +90°C. Water is supplied to the cavity of the external closed loop 1 from below through couplings 4, and steam is discharged from above into a horizontally positioned steam evaporator 7. A steam separator 8 is used to remove condensate from the steam and improve its parameters. Its design returns condensate and unevaporated water back to water collector 10 for evaporation.In this case, temperature control of the internal closed heating loop 2 is not required, as the feedwater level is maintained above the internal closed heating loop 2 and is constantly immersed in the water. This allows the water to remain in the magnetic field for the longest possible time, significantly reducing the energy consumption of the electric induction steam generator. Compared to flow-through steam generators, the absence of a copper closed loop (a copper tube feeding a dose of water for evaporation) makes it possible to implement a "Purge" mode to remove salts and dirt from the electric induction steam generator, reducing feedwater requirements. As the water evaporates, it turns into steam and increases its volume, thereby creating excess pressure in the steam system, which is necessary for the steam load.The purge mode is performed while the electric induction steam generator is operating under steam load, when steam pressure exists in the steam line. During the purge mode, the electric induction steam generator is turned off, then purge port 18 is opened to perform a purge for 10-30 seconds. After this, purge port 18 is closed and the electric induction steam generator is restarted. Purge mode can also be performed before turning off the electric induction steam generator.

[0012] The system is fully automated and ensures the required performance and steam characteristics, provided that all its elements are in good technical condition.

Claims

FORMULA 1. An electric induction steam generator consisting of at least one steam generation unit, which is an external closed loop made of a metal pipe, inside of which a cavity for a coolant is formed and an internal heating closed loop is suspended from a metal busbar or in the form of a cut and slightly spaced pipe, wherein at least one toroidal transformer is installed on the external closed loop, and its internal opening allows the metal pipe of the external closed loop to pass through the toroidal transformer, inside which the internal heating closed loop is located, the lower part of the external closed loop is connected to the water supply system from the feed tank, and the upper part with a branch for removing boiling water with steam into a steam evaporator connected to a steam separator, the steam separator in the lower part is made with an opening for discharging condensate into a water collector,and in the upper part there is a discharge pipe for discharge of purified steam, and the steam separator inside from the bottom up is divided by alternating partitions, the water supply system is made with a blowdown pipe and is connected to a water manifold and through a check valve with a high-pressure pump, the water manifold is designed with the possibility of maintaining the water level inside it above the internal heating closed loop and is made with water level sensors with the help of which the required water level in the steam evaporator is maintained, also the water manifold is connected to the steam separator to form communicating vessels, and the high-pressure pump is connected to the feed tank.

2. An electric induction steam generator according to paragraph 1, characterized in that the external closed loop is located vertically and is made of metal with a high internal resistance relative to the internal closed loop.

3. An electric induction steam generator according to paragraph 1, characterized in that the internal closed heating coil is made in the form of a cut and slightly spaced pipe.

4. An electric induction steam generator according to paragraph 1, characterized in that the internal closed heating coil is made of copper or brass, or their alloys.

5. An electric induction steam generator according to paragraph 1, characterized in that the toroidal transformer is made with low starting currents, the primary windings are wound on the toroidal core and insulated from it.

6. An electric induction steam generator according to item 1, characterized in that the toroidal transformer is installed on vertical and / or horizontal pipes of the outer closed loop.

7. An electric induction steam generator according to paragraph 1, characterized in that the lower part of the outer closed coil is connected to the water supply system through a coupling.

8. An electric induction steam generator according to paragraph 1, characterized in that the steam evaporator is made horizontally oriented to increase the evaporation area of ​​boiling water.

9. An electric induction steam generator according to paragraph 1, characterized in that the steam evaporator is connected to a water supply system to ensure the outflow of excess boiling water.

10. An electric induction steam generator according to paragraph 1, characterized in that pressure and temperature sensors for steam are installed on the steam separator, in its upper part, designed to monitor the parameters of the steam, as well as a mechanical emergency relief valve designed to protect the steam generator from excess pressure.

11. An electric induction steam generator according to paragraph 1, characterized in that the feed tank is provided with a water level sensor and an electromagnetic valve to ensure the possibility of automatically maintaining the water level.

12. An electric induction steam generator according to paragraph 1, characterized in that at least one heat exchanger for cooling the return condensate is designed in the feed tank.

13. An electric induction steam generator according to paragraph 1, characterized in that the feed tank has an inlet for returning condensate, a water drain, and an overflow for the feed tank.

14. A method for generating steam, which includes feeding water into an external closed metal coil of a steam generation unit with an internal heating closed metal coil located therein, designed to heat and evaporate water to produce saturated steam, directing boiling water into a horizontally located steam evaporator to increase the evaporation surface, and then into a steam separator, where the steam is purified from condensate, then the purified steam is supplied to the consumer, and The condensate is returned to the closed external loop of the steam generation unit through a water collector, and in the steam generation unit the feed water level is automatically ensured to be higher than the level of the internal heating closed loop, which allows the water to remain in the magnetic field for the longest possible time.

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