RU2484366C2 - Fast segmented heating of fluid medium - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: fluid medium heating device has a fluid medium passage from the inlet to the outlet with multiple heating sections positioned along the passage. Each heating section represents at least one pair of electrodes with electric current flowing between them through the fluid medium for resistive heating of the fluid medium during its flow along the passage. At least one heating section has a segmented electrode consisting of multiple electrically divisible segments. The controller determines the required voltage and current supplied to the fluid medium by each heating section, taking into account the variation of inlet conductivity as well as the fluid medium conductivity depending on temperature. The controller actuates the selected segments of the segmented electrode to provide for the segmented electrode supplying the required current and voltage to the fluid medium.

EFFECT: possibility to control the segmented electrode effective area with selective actuation of segments.

2 cl, 3 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a device, system and method for rapidly heating a fluid, and more particularly, to a device, system and method for rapidly heating a fluid using electrical energy.

State of the art

Hot water systems of one kind or another are installed in most residential and office buildings in developed countries. In some countries, the most common source of energy for heating water is electricity.

Of course, as is well known, the production of electricity by burning fossil fuels significantly contributes to environmental pollution and global warming. For example, in 1996, the largest electricity-consuming sector in the United States was apartment buildings, which accounted for 20% of all carbon emissions. Of all the carbon emissions from this electricity-consuming sector, 63% directly related to the burning of fossil fuels used to generate electricity for this sector.

In developed countries, electricity is now considered a practical necessity for residential buildings, and with an increase in electricity consumption per apartment building of approximately 1.5% per year since 1990, the planned increase in electricity consumption for the residential sector has become the focus of discussions on stabilization carbon emissions and consistent with the objectives of the Kyoto Protocol.

From 1982 to 1996, the number of households in the United States increased at a rate of 1.4% per year, while residential electricity consumption increased at a rate of 2.6% per year over the same period. Accordingly, it is planned to increase the number of households in the United States by 1.1% per year until 2010, while it is expected that residential consumption will increase electricity at a rate of 1.6% per year over the same period.

According to estimates made in 1995, approximately 40 million households worldwide have used electric water heating systems. The most common type of electric hot water heating system includes a storage tank in which water slowly heats up over time to a predetermined temperature. The water in the storage tank is maintained at a predetermined temperature since the water is taken from the storage tank and filled with cold incoming water. Typically, storage tanks include an electric contact electric immersion element connected to an electrical source of the network, the operation of which is controlled by a thermostat or a temperature control device.

Electric hot water storage systems are generally considered energy inefficient because they operate on the principle of storing and heating water to a predetermined temperature that is higher than the temperature required for use, even though the consumer may not need hot water until some time in the future. Since thermal energy is lost from the hot water in the storage tank, additional consumption of electrical energy may be required to re-heat the water to a predetermined temperature. Finally, the consumer may not need hot water for some extended period of time. However, during this time, some electric hot water storage systems continue to consume energy to heat the water, in order to make sure that the consumer needs hot water at any time.

Rapid heating of the water in such a way that the water temperature reaches a predetermined level in a short period of time allows the system to avoid the inefficiencies that necessarily arise as a result of the storage of hot water. Currently, fast or “instant” hot water heating systems are available, in which both gas, such as natural gas or LPG (liquefied petroleum gas), and electricity are used as an energy source. When using natural gas or LPG (liquefied petroleum gas), they are fuel sources that are particularly well suited for rapid heating of the fluid, since ignition of these fuels can create sufficient heat energy transfer to the fluid and raise the temperature of this fluid to a satisfactory level for a relatively short time under controlled conditions.

However, although fuel sources of natural gas can be used to quickly heat water, these sources are not always reliably available. In contrast, electricity is readily available to most households in developed countries.

There are other existing electrical “instantaneous” hot water systems. One heating method is known as a heated wire system in which the wire is placed in a non-conductive electricity environment or enclosure. During operation, water passes through the environment or through the wire body, either in contact or at a very close distance from the wire or wire body. The wire, to which the energy is supplied, will be heated as a result and thereby transmit thermal energy to water. Control is usually carried out by monitoring the temperature of the water at the outlet and comparing this temperature with the set temperature parameters. Depending on the measured temperature of the water at the outlet, a controlled voltage is applied to the wire until the water temperature reaches the required set temperature parameters.

Although a system such as a heated wire avoids the energy inefficiencies caused by storing hot water, it unfortunately has a number of other disadvantages. In particular, it is necessary to heat the wire to temperatures that are much higher than the temperature of the surrounding water. This has an adverse effect, causing the formation of crystals of dissolved salts, usually present in various concentrations in water, such as calcium carbonate and calcium sulfate. The hot zones of the wire or case in direct contact with water create an excellent environment for the formation of crystals of these types, which leads to the fact that the wire or case becomes “sintered” and thus reduces the efficiency of heat transfer from the wire to the surrounding water. Since the pipe is usually small in diameter, the formation of crystals can also reduce the flow of water through the pipe. In addition, systems such as a heated wire require relatively high water pressures for efficient operation, and thus these systems are not effective for use in areas where there is a relatively low water pressure, or drops in water pressure are frequent, which may occur during peak use water.

Another proposed instantaneous hot water system is an electromagnetic induction system that works like a transformer. In this case, the currents induced in the secondary winding of the transformer cause heating of the secondary winding. The heat generated here is distributed through the circulating water through the water jacket that surrounds the secondary winding. Heated water then exits the system for use. Control is usually carried out by monitoring the temperature of the water at the outlet of the water jacket and comparing this temperature with the set temperature parameters. Depending on the measured temperature of the water at the outlet, the voltage applied to the primary winding can be changed, which changes the electric currents induced in the secondary winding until the water temperature reaches the required set temperature parameters.

Although a system such as electromagnetic induction avoids the energy inefficiencies caused by storing hot water, it also has a number of disadvantages. In particular, it is necessary to heat the secondary winding to temperatures higher than the temperature of the surrounding water. This has the same effect, causing the formation of crystals of dissolved salts, as described above. Since the gap between the secondary winding and the surrounding water jacket is usually relatively narrow, crystal formation can also reduce the flow of water through the jacket. In addition, the generated magnetic fields and high currents induced in the secondary winding can lead to unacceptable levels of electrical or high-frequency noise. This electrical or high-frequency noise can be difficult to suppress or shield, and it affects other sensitive electromagnetic devices within the range of electromagnetic fields.

Any description of documents, actions, materials, devices, products, or the like that has been included in this application is provided solely for the purpose of creating a context for the present invention. This should not be taken as an assumption that any or all of these materials are part of the prior art or were well known in the field related to the present invention, since they existed prior to the priority date of each claim of this application.

Throughout the text of the description, the word “contain” or its variants, such as “contains” or “comprising”, should be understood as implying the inclusion of the said element, whole or stage, or group of elements, whole or stages, and not the exclusion of any other element, whole or stage, or group of elements, whole or stages.

Disclosure of invention

According to a first aspect of the present invention, there is provided a method for heating a fluid, the method comprising:

passing the fluid through the passage from the inlet to the outlet, the passage comprising at least a first and a second heating section arranged along the passage so that a fluid passing through the first heating section then passes a second heating section, each heating section comprising at least at least one pair of electrodes between which an electric current passes through the fluid to resistively heat the fluid as it passes through the passage, with at least one of section contains at least one segmented electrode containing a plurality of electrically separable segments, providing control of the effective active area of the segmented electrode by selectively activating the segments so that when voltage is applied to the segmented electrode, the current consumption will depend on the effective active area;

inlet fluid conductivity measurement;

determining, based on the measured conductivity of the fluid, the required voltage and current supplied to the fluid by the first heating section to increase the temperature of the fluid by a first desired amount;

determining a changed fluid conductivity as a result of the operation of the first heating section;

determining, based on the changed conductivity of the fluid, the required voltage and current supplied to the fluid by the second heating section to increase the temperature of the fluid by a second desired amount; and

activation of segments of a segmented electrode in such a way as to supply the desired current and voltage to the segmented electrode.

According to a second aspect of the present invention, there is provided a device for heating a fluid, comprising:

passage of fluid from inlet to outlet;

at least the first and second heating sections located along the passage so that the fluid passing through the first heating section then passes through the second heating section, with each heating section containing at least one pair of electrodes between which an electric current passes through the fluid for resistively heating the fluid during its passage through the passage, and at least one of the heating sections contains at least one segmented electrode containing ETS electrically separated segments, providing effective control of the active area of the segmented electrode by selectively activating the segments such that upon application of a voltage to the segmented electrode current consumption will depend upon the effective active area;

conductivity sensor for measuring the conductivity of the fluid inlet; and

a controller for determining, based on the measured conductivity of the fluid, the required voltage and current supplied to the fluid by the first heating section to increase the temperature of the fluid by the first required amount, to determine the changed conductivity of the fluid as a result of the operation of the first heating section, to determine based on the changed conductivity the fluid of the required voltage and current supplied to the fluid by the second heating section to increase the temperature of the fluid n a second desired amount, and for activating segments of the segmented electrode so as to realize the required supply voltage and current of the segmented electrode combination selected.

By providing a segmented electrode and selectively activating segments of a segmented electrode, the present invention provides control over the voltage / current mode under which this heating section will operate. This allows the embodiments of the invention to demonstrate better adaptability to the variability of the electrical conductivity of the fluid between different places and / or different time periods, while remaining within the boundaries of voltage and current.

In preferred embodiments of the invention, changes in the conductivity of the fluid are substantially constantly adapted in response to measurements of the conductivity of the incoming fluid. The conductivity of the fluid can also be determined based on the current consumption after applying voltage to one or more electrodes of one or more heating sections.

Changes in fluid conductivity will cause changes in the amount of electric current consumed by the system. Preferred embodiments of the invention prevent such changes from causing the peak current value to exceed nominal values by using the measured conductivity value to initially select the appropriate combination of electrode segments set before operating the system. In such embodiments, the combined surface area of the selected electrode segments is specifically calculated to ensure that the nominal maximum values of the electric current in the system are not exceeded.

In addition, preferred embodiments of the invention use measured fluid conductivity to ensure that there is no violation of a predetermined range of acceptable fluid conductivity within which the system is intended to operate.

In preferred embodiments of the invention, each heating section comprises a segmented electrode. Such embodiments of the invention make it possible to control the effective electrode area of each heating section by selectively activating the segments of the segmented electrode of such a heating section.

The specified or each segmented electrode is preferably divided into segments of different sizes to allow you to choose a combination of segments, which will provide increased accuracy in choosing the desired effective area. For example, if the segmented electrode is divided into three segments, the segments preferably have corresponding effective areas in a 1: 2: 4 ratio, that is, the segments preferably comprise four sevenths, two sevenths, or one seventh of the total effective area of the electrode, respectively. In such embodiments of the invention, the corresponding activation of the three electrode segments allows you to select any one of the seven available effective areas. Other ratios of segment area and number of segments may be provided.

In a preferred embodiment of the invention, each electrode segment of the segmented electrode extends substantially perpendicular to the direction of flow of the fluid so as to expose the fluid to resistive heating over substantially the entire passage of the fluid.

In addition, the selection of the electrode segment is preferably carried out in such a way as to ensure that the peak current limits are not exceeded. In such embodiments of the invention, the measurement of inlet conductivity prevents the operation of the device if such current limits are not safely observed.

In embodiments of the invention in which the fluid flow rate is not substantially constant or unknown, a fluid flow meter is preferably provided to assist in appropriate determinative monitoring of the current, voltage, and activation of the electrode segment at varying fluid flow rates.

In addition, by providing a plurality of heating sections, the present invention allows each heating section to operate in such a way as to provide changes in the electrical conductivity of the fluid with increasing temperature of the fluid. For example, water conductivity increases with temperature, on average, by about 2% per degree Celsius. When the fluid must be heated to tens of degrees Celsius, for example, from room temperature to 60 degrees Celsius or up to 90 degrees Celsius, the conductivity of the fluid at the inlet can be substantially different from the conductivity of the fluid at the outlet. Subsequently, resistive heating of the fluid in successive heating sections along the passage allows each heating section to operate within a limited temperature range. Thus, each heating section can supply voltage and current that are applicable to fluid conductivity within this limited temperature range, rather than attempting to apply voltage and current with respect to one or averaged conductivity over the entire temperature range.

Embodiments of the invention preferably further comprise an upstream fluid thermometer for measuring the temperature of the fluid at the outlet to provide feedback control of the heating of the fluid.

Preferably, each heating section comprises substantially flat electrodes between which a fluid passage passes. Alternatively, each heating section may comprise substantially coaxial cylindrical or flat electrodes with a fluid passage containing an annular space. The passage of the fluid may form many parallel passages for the fluid.

In one embodiment of the invention, the second temperature measuring means measures the temperature of the fluid between the first and second heating sections, wherein the control means controls the power to the first and second heating sections in accordance with the measured temperatures and the desired increase in the temperature of the fluid in each respective heating section.

Other embodiments of the invention may include three or more heating sections, each of which has an inlet and an outlet, the sections being connected in series, and a control means that initially selects the electrode segments in accordance with the measured conductivity of the incoming fluid and controls the power to the electrode pair of each section in accordance with the measured temperatures at the inlet and outlet of each section and the desired desired temperature difference for each section.

In preferred embodiments of the invention, the control means supplies a varying voltage to the electrode pair of each heating section by transmitting the selected half-wave cycles from the AC voltage source. For example, half-wave cycles can be transmitted at a cycle frequency determined by a pulse control system and being an integer part of the frequency of the AC power supply voltage source, so that controlling the power supplied to the selected combination of electrode segments includes changing the number of control pulses per unit of time.

The desired fluid temperature at the outlet can be adjusted by the user through an adjustable control means.

The volume of fluid passing between any set of electrodes is preferably determined by measuring the size of the channel within which the fluid is exposed to electrodes taken together with the fluid stream.

Similarly, the time during which a given volume of fluid will receive electrical power from the electrodes can be determined based on the flow rate of the fluid through the fluid passage. The increase in the temperature of the fluid is proportional to the amount of electrical power applied to the fluid. The amount of electrical power needed to raise the temperature of the fluid by a known amount is proportional to the mass (volume) of the fluid that is heated and the flow rate of the fluid through the channel. The measurement of the electric current passing through the fluid can be used as a unit of electrical conductivity, or the specific conductivity of this fluid, and therefore provides the choice of segments to be activated, together with monitoring and control of the required change in the applied voltage required to keep the applied electrical power constant or at the required level. The electrical conductivity and, therefore, the conductivity of a fluid that is heated will change with increasing temperature, thereby creating a conductivity gradient along the fluid path.

The energy required to raise the temperature of the mass of the fluid can be determined by combining the two equations:

Equation (1)

Energy = Specific Heat × Density × Volume × Temperature Change

or

The energy per unit time required to increase the temperature of the fluid mass can be determined using the equation:

For the purpose of analysis, the specific heat of water, for example, can be considered constant between temperatures of 0 degrees C and 100 degrees C. A water density of 1 can also be considered constant. Therefore, the amount of energy needed to change the temperature of a unit mass of water 1 degree C per 1 second, is considered as constant, and it can be indicated by "k". The ratio Volume / Time is equivalent to the flow rate (Fr). Thus, the energy per unit time needed to increase the temperature of the fluid mass can be determined using the equation:

Thus, if the desired temperature change is known, the flow rate can be determined, while the required power can be calculated.

Typically, when a consumer needs heated water, a faucet operates, causing water to flow through the fluid passage. This water flow can be detected by a flow meter and cause the start of a heating cycle. The inlet water temperature can be measured and compared with the set desired temperature for the water at the outlet of the system. From these two values, the desired change in water temperature from inlet to outlet can be determined.

Of course, the inlet water temperature in the segmented electrode section can be re-measured over time, and since the value for the changes in the measured inlet water temperature changes, the calculated value for the necessary temperature change from the inlet to the outlet from the segmented electrode sections can be adjusted, respectively. Similarly, with changes in temperature, mineral content, etc., changes in electrical conductivity and, therefore, in the specific conductivity of a fluid can occur over time. Accordingly, the flow of current through the fluid will change, causing a change in the final power applied to the water, and this can be controlled by selectively activating or deactivating the segments of the segmented electrode (s) within the section. Repeated measurement of the temperature at the outlets of the heating sections over time and comparison of these data with the calculated values of the temperature at the outlet will allow us to continuously optimize the voltage applied to the electrodes using repeated calculations.

In one preferred embodiment of the invention, computing means provided by a microcomputer control system is used to determine the electric power to be applied to the fluid passing between the electrodes by determining the electric power value that will affect the desired temperature change between the inlet and outlet of the heating section , measuring the effect of changes on the conductivity of water, and thereby choosing the appropriate activation segment nt and calculating the voltage that must be applied for a given flow rate.

Equation (2) Electrical power control

In preferred embodiments, the implementation of the present invention measures the electric current flowing between the electrodes inside each heating section and, therefore, through the fluid. The inlet and outlet temperatures of the heating section are also measured. Measurement of electric current and temperature allows the computing means of the microcomputer control system to determine the required power that must be applied to the fluid in each heating section in order to increase the temperature of the fluid by the required amount.

In one embodiment of the invention, the computing means provided by the microcomputer control system determines the electrical power to be applied to the fluid passing between the segmented electrodes of each heating section, selects which segment to activate in each segmented electrode, and calculates the average voltage that is needed apply to cause the required temperature change.

Equation (2) below makes it easy to calculate the electrical power that needs to be applied, as accurately as possible, almost instantly. As applied to water heating systems, this eliminates the need for unnecessary use of water, which is otherwise required to initially pass through the system before facilitating the supply of water at the required temperature. This creates the potential for saving water or other fluid.

In preferred embodiments of the invention, by determining the electrical power to be supplied to the fluid passing between the electrodes, the computing means can then calculate the voltage to be applied to each electrode section (ES) as follows. Once the power required for the electrode section has been calculated and the current consumed by the electrode (n) has been measured (which for segmented electrodes includes the total current consumed by the activated segment (s) of the segmented electrode section), then:

Equation (2)

Voltage ES _n (V _{adj n} ) = Power ES _n (P _{req n} ) / Current ES _n (I _sn )

V _{adj n} = P _{req n} / I _n

As part of the initial heating cycle, the applied voltage can be set to a relatively low value in order to determine the initial conductivity of the fluid passing between the electrodes. Applying voltage to the electrodes will induce a current that will be consumed through the fluid passing between the electrodes, thus allowing the specific conductivity of the fluid to be determined, which is directly proportional to the current consumed through it. Accordingly, having determined the electric power that should be supplied to the fluid flowing between the electrodes in each heating section, it is possible to determine the required voltage, which should be applied to those electrodes in order to increase the temperature of the fluid flowing between the electrodes in each heating section to the required value. The instantaneous current consumed by the fluid is preferably constantly monitored to vary along the passage length of the fluid. Any change in the instantaneous current consumed anywhere along the channel is an indication of a change in electrical conductivity or conductivity of the fluid. The changing values of the specific conductivity, which are manifested in the fluid passing between the electrodes in the electrode sections, actually form a gradient of the specific conductivity along the heating path.

Preferably, various parameters are continuously monitored and calculations are continuously performed to determine the electric power to be supplied to the fluid and the voltage to be applied to the electrodes in order to raise the temperature of the fluid to a predetermined desired temperature in a predetermined period.

Brief Description of the Drawings

An example of the invention will be described below with reference to the accompanying drawings, in which:

Figure 1 is a schematic block diagram of a fluid heating system according to one embodiment of the invention;

Figure 2 is a perspective view of a segmented electrode containing three segments; and

Figure 3 is a diagram of the passage of a fluid passing through three heating sections, each heating section comprising one electrode segmented into three segments.

Description of preferred embodiments of the invention

1 is a schematic block diagram of a fluid heating system 100 according to one embodiment of the present invention, in which water flows through the housing 112. The housing 112 is preferably made of a material that is non-conductive, such as synthetic plastic. However, the housing 112 should probably be connected to a metal water pipe, such as a copper pipe, which is electrically conductive. Accordingly, the grounded braided grids 114 shown in FIG. 1 are included in the inlet and outlet of the housing 112 so as to electrically ground any metal pipes connected to the device 100. The grounded grids 114 should ideally be connected to the electrical ground of the electrical installation in which a heating system according to an embodiment of the invention has been installed. Since grounded braided grids 114 can draw current from the electrode, water leakage protection within the control system and / or a circuit breaker or residual current circuit breaker (RCD) can be activated through water flowing through the device 100. In the most preferred form of this embodiment of the invention, the system includes protective devices in the event of a leakage of current to the ground.

When an outlet valve (not shown) is open, water flows through the housing 112, as indicated by the passage arrows 102.

The pipe 112, which forms the fluid passage, is provided with three heating sections containing respective groups of electrodes 116, 117 and 118. The electrode material may be any suitable metal or non-metallic conductive material, such as conductive plastic, carbon impregnated material or the like. It is important that the electrodes are selected from the material to minimize chemical reaction and / or electrolysis.

The segmented electrode of each electrode pair is a segmented electrode 116a, 117a and 118a connected to a common switchable reverse circuit 119 through separate voltage source power control devices Q1, Q2, ..., Q9, and another electrode from each electrode pair 116b, 117b and 118b connected to incoming single-phase or three-phase voltage source 121,122 and 123, respectively. The individual devices Q1, Q2, ..., Q9 of regulating the power of the voltage source switch the common reverse circuit in accordance with the power control control provided by the microprocessor control system 141. The total electric current supplied to each individual heating section 116, 117 and 118 is measured using current measuring devices 127, 128 and 129, respectively. Current measurements are supplied as an input signal through an inlet interface 133 to a microprocessor control system 141 that acts as a power supply controller.

The microprocessor control system 141 also receives signals through an inlet interface 133 from a flow rate measuring device 104 located in the pipe 112 and a temperature setting device (not shown), with which the user can set the desired temperature of the fluid at the outlet. The volume of fluid passing between any group of electrodes can be precisely determined by measuring in advance the dimensions of the channel within which the fluid is exposed to electrodes taken in combination with the fluid flow. Similarly, the time during which a given volume of fluid will receive electrical power from the electrodes can be determined by measuring the flow rate of the fluid through the channel. The increase in the temperature of the fluid is proportional to the amount of electrical power applied to the fluid. The amount of electrical power needed to raise the temperature of the fluid by a known amount is proportional to the mass (volume) of the fluid that is heated and the flow rate of the fluid through the channel. The measurement of the electric current flowing through the fluid can be used as a unit for measuring the electrical conductivity or specific conductivity of this fluid and, therefore, allows you to determine the necessary change in the applied voltage, which is required to keep the applied electric power constant. The electrical conductivity and, therefore, the conductivity of a fluid that is heated will change with increasing temperature, thus creating a conductivity gradient along the fluid path.

The microprocessor control system 141 also receives signals through the signal inlet interface 133 from the inlet temperature measuring device 135 to measure the temperature of the fluid at the inlet to the pipe 112, from the outlet temperature measuring device 136 measuring the temperature of the fluid exiting the pipe 112 from a first intermediate temperature measuring device 138 for measuring the temperature of the fluid between the heating sections 116 and 117, and from a second intermediate temperature measuring device 139 for measuring I fluid temperature between the heating sections 117 and 118.

The device 100 according to the present invention is further adapted to be consistent with changes in fluid conductivity that occur either from the specific location in which the device is installed or from time to time in a single place. In this regard, the inlet fluid conductivity sensor 106 continuously measures the conductivity of the fluid inlet to the fluid passage 112. Changes in the conductivity of the fluid will cause changes in the magnitude of the electric current consumed by each electrode for a given applied voltage. This embodiment monitors such changes and ensures that the device consumes the required current level using the measured conductivity value to initially select the appropriate combination of electrode segments before allowing the system to operate. Each electrode 116a, 117a and 118a is segmented into three electrode segments 116ai, 116aii, 116aiii, 117ai, 117aii, 117aiii, 118ai, 118aii and 118aiii. For each respective electrode, a segment ai is usually provided, typically comprising about one seventh of the active area of the electrode, segment aii, typically comprising about two sevenths of the active area of the electrode, segment aiii, typically comprising about four sevenths of the active area of the electrode. Selecting appropriate segments or corresponding combinations of segments thus allows the effective electrode area to be any one of seven available values for the electrode area. Subsequently, for a fluid with high conductivity, a smaller electrode area can be selected so that for a given voltage, the current consumed by the electrode will be prevented from rising above the required or safe level. Conversely, for a fluid with low conductivity, a larger electrode area may be chosen such that for the same given voltage, sufficient current will be consumed to effect the required power transmission of the fluid. Segment selection can simply be done by activating or deactivating the power switching devices Q1, ..., Q9, if necessary.

In particular, the combined surface area of the selected electrode segments is specifically calculated to ensure that the average maximum electric currents of the system are not exceeded.

The microprocessor control system 141 receives various controlled input signals and performs the necessary calculations with respect to the selection of the active area of the electrode, the required electrode pair voltages and currents to provide the calculated power to the fluid flowing through the channel 112. The microprocessor control system 141 controls the pulse voltage supply from each of three separate phases connected to each of the electrode pairs 116, 117 and 118. Each pulse voltage supply is separately controlled uetsya separate control signals from the microprocessor control system 141 to the power switching devices Q1, ..., Q9.

Therefore, it can be seen that, based on various parameters for which the microprocessor control system 141 receives characteristic input signals, the computing means, under the control of the program inside the microprocessor control system 141, calculates the control pulses requested by the power switching devices in order to supply the necessary electric power so that cause the desired temperature change in the water flowing through the channel 112, so that the heated water is supplied from the channel 112 when not bhodimoy temperature, predetermined temperature setting device, controllable by the user.

When the user sets the desired water temperature at the outlet using the temperature setting device, the set value is entered into the microprocessor control system 141 and stored in the system memory until it changes or is reinstalled. Preferably, a default value of 50 degrees Celsius is stored in the memory, and the temperature setting device may provide a visual indication of the temperature setting. The microprocessor control system 141 may have a predetermined maximum for the temperature setting device, which is the maximum temperature value above which the water cannot be heated. Thus, the value of the temperature setting device cannot be greater than the maximum set value. The system can be designed so that if for any reason the temperature determined by the exhaust temperature device 136 was greater than the set maximum temperature, the system will be immediately shut down and deactivated.

The microprocessor control system 141 re-runs a series of checks to ensure that

(a) the temperature of the water at the outlet does not exceed the maximum allowable temperature;

(b) the leakage of current to earth did not exceed the specified set value; and

(c) the system current does not exceed a predetermined system current boundary.

These checks are carried out repeatedly during the operation of the unit, and if any of the checks determines a violation of the controlled limits, the system is immediately deactivated. When the initial check of the system is satisfactorily performed, a calculation is performed to determine the necessary voltage that must be applied to the water flowing through the channel 112 in order to change its temperature by the desired value. The calculated voltage is then applied to the pairs of electrodes 116, 117, 118 so as to quickly increase the temperature of the water as soon as it flows through the channel 112.

As the temperature of the water flowing through the channel 112 increases from the inlet end of the channel, the conductivity changes in response to an elevated temperature. The intermediate temperature measuring devices 138 and 139 and the outlet temperature measuring device 136 measure incremental temperature changes in three heating sections of the channel 112, containing groups of electrodes 116, 117 and 118, respectively. The voltage applied to the respective pairs of electrodes 116, 117 and 118 can then be changed to take into account changes in the conductivity of the water, to ensure that a uniform increase in temperature occurs along the length of the channel 112, in order to maintain a substantially constant power signal from each of the group of electrodes 116 , 117, 118 and in order to ensure the greatest efficiency and stability in heating water between measuring the temperature at the inlet at 135 and measuring the temperature at the outlet at 136. The power supplied to the flowing water is changed by controlling control pulses supplied by activated power switching devices Q1, ..., Q9, commensurate with the required capacity. This helps to increase or decrease the power supplied by the individual electrode pairs 116, 117 and 118 to the water.

System 100 re-monitors water from the point of view of changes in its conductivity by continuously polling the conductivity sensor 106, and also referring to current measuring devices 127, 128 and 129, as well as temperature measuring devices 135, 136, 138 and 139. Any changes in the conductivity values of the water within the system resulting from changes in increases in water temperature, changes in water temperatures, as determined along the length of the pipe 112, or changes in certain currents consumed by water, cause the computing tool to calculate revised average voltage values that should be applied to electrode pairs. Changes in the conductivity of the incoming water cause the microprocessor control system 141 to selectively activate the changed combinations of the electrode segments 116ai, 116aii, 116aiii, 117ai, 117aii, 117aiii, 118ai, 118aii and 118aiii so that the set maximum current values are not exceeded. A permanently closed loop that monitors such changes in the system current, currents of individual electrodes, selection of the electrode segment and water temperature causes a conversion of the voltage that must be applied to the individual electrode segments in order to allow the system to supply relatively constant and stable power to the water flowing through the heating system 100. Changes in the conductivity of a fluid or water passing through individual segments of a segmented electrode can be individually controlled by way. Therefore, the system is able to effectively monitor and control the final conductivity gradient throughout the system. Thus, this embodiment provides compensation for changes in the electrical conductivity of a fluid or water caused by varying temperatures and varying concentrations of dissolved chemicals and salts, as well as by heating a fluid or water by varying a varying electrical voltage to match changes in conductivity when the temperature of the fluid or water increases by the required amount.

Figure 2 is a perspective view of a segmented electrode 216a of the heating section 216. The segmented electrode 216a comprises three segments 116ai, 116aii, 116aiii. The corresponding electrical switch allows you to selectively activate any combination of the three segments at any given time. The electrode 216b is a common return wire supply of electricity.

FIG. 3 is a diagram of a fluid passage 302 passing through three heating sections 316, 317, 318. Each heating section includes one electrode section segmented into three segments.

The ideas of US patent 7050706, the contents of which are incorporated herein by reference, can be applied to control the operation of aspects of the present invention and the system.

The segmented electrodes of the present invention can be used in a water heating device comprising a preheated reservoir in which a fluid is heated to a desired preheating temperature and held in a reservoir, wherein the segmented electrodes are used to heat the fluid in the outlet passage through which the fluid passes from the tank if necessary. In this regard, the content of international patent publication WO 2008/116247, filed by the applicant, is incorporated herein by reference.

It should be noted that any suitable number of electrode heating sections can be used in the practice of the present invention. Thus, although the described embodiments of the invention show three heating sections for heating water flowing through the channel 112, the number of heating sections in the channel can be changed in accordance with individual requirements or the specific application for heating the fluid. If the number of electrodes is increased, for example, to six pairs, each individual pair can be individually controlled with respect to the electrode voltage in the same manner as described herein with respect to embodiments of the invention. Similarly, the number of segments into which a single electrode is segmented may differ from three. For example, segmentation of the electrode into four segments having active areas in a 1: 2: 4: 8 ratio provides 15 effective area values that can be selected by the microprocessor control system 141.

Regarding the heating of water, it should be noted that by using electrode pairs that cause current to flow through the water itself so that heat is generated from the electrical resistivity of the water itself, the present invention eliminates the need for conventional electrical resistance elements, thereby avoiding the problems associated with the formation of scale and the formation of scale on the elements.

In addition, it should be understood that the invention can be used in applications that include, but are not limited to, domestic hot water systems and home boiling water dispensers. In relation to these two applications, which are often used for domestic hot water needs, the invention can contribute to both energy and water savings. In addition, it should be understood that the implementation of segmented electrodes containing separately active segments allows you to install such a device in places with very different water conductivity, in which the microprocessor control system 141 can adapt the operation of the device to the specific conductivity encountered, without requiring laborious and expensive changes in physical configuration of the device. Moreover, the principles of the system provide ease of manufacture, ease of installation at the place of use, a pleasant appearance and are consistent with the factors of comfort established by the market. When describing the operating modes of such applications in more detail, we primarily consider hot water systems.

A hot water system in accordance with one embodiment of the invention provides an on-demand free-flow hot water heating system that delivers hot water at a predetermined or constant temperature to one or more kitchens, bathtubs, or laundry rooms for home use. The outlet temperature can be precisely controlled and maintained stable, despite the adverse water delivery conditions that may prevail. The electrical power requirements for this type of application are usually in the range between 3.0 kW and 33 kW and require either a single-phase or multiphase AC electric power source. The requirements for an electrical power source may vary depending on the specific application. The system is designed to deliver hot water to a user at flow rates that typically vary between 0.5 liters / min and 15 liters / min. It also depends on the specific application. The outlet water temperatures can be constant or can be set between 2 degrees Celsius and 6 degrees Celsius, which also depends on the application and home rules. The ability to change temperature will be nominally equal to 50 degrees C at 10 liters / min, but this also depends on the application.

Now we turn to the device for issuing boiling water in accordance with another embodiment of the present invention. The boiling water dispenser in this embodiment of the invention provides a free-flow boiling water dispenser for delivering hot water at a constant outlet temperature to a maximum temperature of 98 degrees Celsius. This unit will most often be installed at the place of use in the kitchen. The outlet temperature is precisely controlled and maintained stable, despite the adverse water supply conditions that may prevail. Electrical power requirements for this type of application are usually in the range between 1.2 kW and 6 kW. The flow rate of this dispenser is constant. It will be nominally fixed between 0.5 l / min or 1.2 l / min, but this also depends on the application. Power requirements are dependent on application requirements.

Now we return to the device for issuing a free flow of boiling water in accordance with a further embodiment of the invention. If such a system needs to deliver boiling water instantly and continuously at a speed between 0.5 l / min and 1.2 l / min without storage or pre-heating, then usually an electric power of 6.6 kW is required and an appropriate source must be installed electrical power. This embodiment of the invention is capable of delivering boiling water almost continuously and without interruption for as long as required. Exceptionally low accident losses of 2 watts per day will be considered. Previously, the delivery of continuous instant boiling water on demand could not be ensured using available technology, a competitive hot water heating system due to the high pressure requirements in the pipelines, which necessarily result in flow rates of more than 2 l / min. It is impractical to use flow rates much greater than 1.2 l / min for boiling water dispensers.

In another embodiment, the present invention provides a two-stage device for dispensing boiling water. If conventional single-phase output powers are to be used, the power requirements remain between 1.8 kW and 2.5 kW, which are acceptable for standard household power outlets and do not require additional or special electrical circuits. This embodiment of the invention requires a two-stage boiling water dispenser system that includes a water storage element as well as a dynamic free flow element. In this regard, the water is first heated to 65 degrees C in a storage system designed to hold nominally from 1.8 liters to 2.0 liters of water. After heating to 65 degrees C, the device for dispensing boiling water becomes operational, i.e. if it is turned on, then water at 65 degrees C is delivered through the dynamic section to the outlet. This dynamic sector heats the water flowing at a speed of 0.8 l / min to 1.2 l / min, on demand for an additional 30 degrees C to an outlet temperature of 95 degrees C.

It will be apparent to those skilled in the art that various changes and / or additions can be made to the invention, as shown in specific embodiments of the invention, without departing from the scope of the invention, as broadly defined herein. Therefore, these embodiments of the invention should be regarded in all aspects as illustrative and not restrictive.

Claims (18)

1. A method of heating a fluid, including:
passing the fluid through the passage from the inlet to the outlet, the passage comprising at least a first and a second heating section arranged along the passage so that a fluid passing through the first heating section then passes a second heating section, each heating section comprising at least at least one pair of electrodes between which an electric current passes through the fluid to resistively heat the fluid as it passes through the passage, with at least one of section contains at least one segmented electrode containing a plurality of electrically separable segments, providing control of the effective active area of the segmented electrode by selectively activating the segments so that when voltage is applied to the activated electrode segment (s), the current consumption will depend on the effective active area ;
inlet fluid conductivity measurement;
determining, based on the measured conductivity of the fluid, the required voltage and current supplied to the fluid by the first heating section to increase the temperature of the fluid by a first desired amount;
determining an altered fluid conductivity as a result of the operation of the first heating section;
determining, based on the changed conductivity of the fluid, the required voltage and current supplied to the fluid by the second heating section to increase the temperature of the fluid by a second desired amount; and
activation of segments of the segmented electrode in such a way as to supply the required current and voltage to the segmented electrode. 2. The method according to claim 1, in which changes in the conductivity of the fluid is essentially constantly taken into account in response to measurements of the conductivity of the incoming fluid. 3. The method according to claim 1 or 2, in which the conductivity of the fluid is determined based on the current consumed by applying voltage to one or more electrodes of one or more heating sections. 4. The method according to claim 1, further comprising using the measured conductivity value for the initial selection of the installed appropriate combination of electrode segments to ensure that the system works to prevent the peak value from being exceeded by peak current caused by changes in fluid conductivity. 5. The method according to claim 1, further comprising deactivating the electrodes if the measured conductivity of the fluid is outside a predetermined range of acceptable conductivity of the fluid. 6. The method according to claim 1, further comprising measuring the flow rate of the fluid to help determine the corresponding current, voltage, and activation of the electrode segment at varying flow rates of the fluid. 7. The method according to claim 1, further comprising measuring the temperature of the fluid at the outlet to provide feedback control by heating the fluid. 8. The method according to claim 1, further comprising measuring the temperature of the fluid between the first and second heating sections and controlling the power to the first and second heating sections in accordance with the measured temperatures and the desired increase in temperature of the fluid in each respective heating section. 9. The method according to claim 1, wherein the fluid passage comprises three or more heating sections, each of which has an inlet and an outlet, the sections being connected in series, the method further comprising a control means initially selecting electrode segments in accordance with the measured conductivity incoming water and controlling the power to the electrode pair of each section in accordance with the measured temperatures at the inlet and outlet of each section and a given desired temperature difference for each section. 10. A device for heating a fluid containing:
passage of fluid from inlet to outlet;
at least the first and second heating sections located along the passage so that the fluid passing through the first heating section then passes through the second heating section, with each heating section containing at least one pair of electrodes between which an electric current passes through the fluid for resistively heating the fluid during its passage through the passage, and at least one of the heating sections contains at least one segmented electrode containing ETS electrically separated segments, providing effective control of the active area of the segmented electrode by selectively activating the segments such that upon application of a voltage to the segmented electrode current consumption will depend upon the effective active area;
conductivity sensor for measuring the conductivity of the fluid inlet; and a controller for determining, based on the measured conductivity of the fluid, the required voltage and current supplied to the fluid by the first heating section to increase the temperature of the fluid by a first desired amount, to determine the changed conductivity of the fluid as a result of the operation of the first heating section, to determine based on the changed fluid conductivity of the required voltage and current supplied to the fluid by the second heating section to increase the temperature of the fluid the second required value, and to activate the segments of the segmented electrode in such a way as to supply the required current and voltage to the segmented electrode. 11. The device according to claim 10, in which each heating section contains a segmented electrode. 12. The device according to claim 10, in which each segmented electrode is divided into segments of different sizes to provide a choice of combinations of segments to provide increased accuracy in choosing the desired effective area. 13. The device according to item 12, in which the segmented electrode is divided into n segments having a relative effective area in a ratio of 1: 2: ...: 2 ^(n-1) . 14. The device of claim 10, wherein each electrode segment of the segmented electrode extends substantially perpendicular to the direction of fluid flow in order to resistively heat the fluid substantially along the entire passage of the fluid. 15. The device of claim 10, further comprising means for measuring a flow rate for measuring a flow rate of a fluid to help determine an appropriate current, voltage, and activation of an electrode segment at varying flow rates of a fluid. 16. The device of claim 10, further comprising means for measuring the temperature of the fluid at the outlet for measuring the temperature of the fluid at the outlet to provide feedback control of the heating of the fluid. 17. The device according to claim 10, further comprising means for measuring the temperature of the fluid for measuring the temperature of the fluid between the first and second heating sections and controlling the power to the first and second heating sections in accordance with the measured temperatures and the desired increase in the temperature of the fluid in each respective heating sections. 18. The device of claim 10, in which the passage of the fluid contains three or more heating sections, each of which has an inlet and an outlet, while the sections are connected in series.

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