On-demand rapid steam generator

Abstract

A steam generator for the near-instantaneous production of steam includes a set of parallel electrodes provided at fixed distances from one another. The electrodes are enveloped in a housing that allows for electrode contacts to protrude through a wall of the housing to connect with an electrical power source. The housing further allows for pressurization to realize higher temperatures. Preheated water is introduced to the heater and heated to the vaporization temperature, then boiled into steam.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of the filing date of provisional U.S. patent application Ser. No. 63 / 754,389 filed on Feb. 5, 2025.BACKGROUND

[0002] Steam boilers for use in or with coffee or espresso machines, and other such devices for making hot beverages, are well-known. For example, steam can be used for frothing, foaming and heating milk for cappuccinos, lattes and the like. In machines having dual boilers, a hot water boiler is provided for making espresso and a separate steam boiler is provided for generating steam. This affords a high degree of control over the temperatures and pressures in each boiler. In some instances, the hot water boiler may provide supplemental hot water to the steam boiler.

[0003] A representative depiction of a conventional steam boiler is presented in FIG. 1. As shown, from top to bottom, the heater assembly 101 includes a vessel 102 having ports 103 and other fittings positioned along the top of the vessel 102. Sensors 106 extend downwardly through the ports 103 into the interior “I” of the vessel 102 for sensing the temperature and level of the water. A heating element such as an electric resistive element 108 is positioned at the bottom of the vessel 102 and may be in the shape of a coil having electrical connections 110 that extend out of the bottom of the vessel 102.

[0004] In operation, the heater assembly 101 would typically be filled approximately halfway with water, with steam making up the upper half of the vessel 102. At steady state, the heater assembly 101 has an internal temperature of about 120° C., at a pressure of about 1.1 bar. These properties are consistent with the water vapor saturation curve.

[0005] When there is a demand for steam, a valve (not shown) supported on the vessel 102 allows steam to exit one of the ports 103 at the top of the heater assembly 101 and directs the steam to a steam wand (not shown) connected to the respective port 103. As the pressure starts to drop within the vessel 102, the water at 120° C. within the vessel 102 will transition to vapor (steam) and exit the vessel 102 through the respective port 103 and travel to the steam wand. The steam exits the steam wand (not shown) such that the steam provided to the wand can froth, heat, and foam milk.

[0006] Typically, a pressure sensor is provided in communication with one of the ports 103 on the top of the heater assembly 101. When the pressure drops below the setpoint, e.g., about 1.1 bar, more heat is demanded, and the heating element 108 is energized. Heating is stopped once the setpoint pressure is achieved. The pressure is therefore used to set the conditions, both temperature and pressure, within the vessel 102. Makeup water is provided to the vessel 102 when a water level sensor within the vessel 102 indicates a low-water condition, in which the water within the vessel 102 is below a predetermined level.

[0007] To produce steam by this method, a relatively large vessel is required, which negatively impacts available room in the coffee maker enclosure. The surface area of such vessel is similarly large. Further, the two-phase mixture of steam and water needs to be constantly maintained at a high temperature to be promptly available when demanded. Given the large surface area and the high temperature, resulting thermal losses though natural convection can be quite significant.

[0008] Additionally, because of the relatively high temperatures in the steam boiler, scaling can become an issue. Scaling typically consists of the deposition of layers of solid minerals, such as Calcium and Magnesium, from the water onto surfaces of the heating assembly 101 in contact with the water. The degree of scaling is a function of temperature, with more scaling occurring at higher temperatures. The surface of the heating element 108 is especially susceptible to scaling, since the heating element 108 reaches a much higher temperature than the bulk water. Scaling reduces the efficiency of heat transfer from the heating element 108 to the water, drives the frequency of maintenance of the heater assembly 101 up, and can reduce the life span of the heater assembly 101. Accordingly, further improvements would be beneficial.SUMMARY

[0009] An aspect of the present disclosure provides a steam or vapor generator, hereinafter steam generator, for the generation of steam or vapor from hot water or other liquid. The steam generator may include a structure to define multiple parallel channels, each of the parallel channels defined by electrode plates of an electrode array arranged with parallel surfaces at given spacings. The steam generator may also include a hot water inlet and a vapor outlet. The electrodes are desirably in electrical communication with contacts that pass through a wall of a housing of the steam generator, and which are in turn selectively electrically energized.

[0010] A further aspect of the present disclosure includes a flow channel running transverse to the electrode array for the distribution of hot water to the parallel channels between the electrode plates.

[0011] A further aspect of the present disclosure includes sizing the geometry of the electrodes to effectively heat the two-phase mixture (water and steam) to the desired temperature.

[0012] Steam generators in accordance with aspects of the present disclosure may beneficially result in a compact device that does not require large areas susceptible to heat loss. Steam generators, in accordance with aspects of the present disclosure may also beneficially only provide heat when required, i.e. when steam is demanded, thus reducing energy usage. Steam generators in accordance with aspects of the present disclosure may further be less susceptible to scale buildup.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a partially cut-away, elevational view of a conventional steam boiler;

[0014] FIG. 2 is a side, perspective view of a steam generator in accordance with aspects of the present disclosure;

[0015] FIG. 3 is a partially exploded, perspective view of the steam generator of FIG. 2;

[0016] FIG. 4 is an exploded perspective view of a power cap sub-assembly of the steam generator of FIG. 2;

[0017] FIG. 5 is a vertical cross section of the steam generator of FIG. 2;

[0018] FIG. 6 is a schematic diagram of steam generation system illustrating a fluid flow through the steam generation system;

[0019] FIG. 7 is a cross-sectional view taken along section line 7-7 of FIG. 5;

[0020] FIG. 8 is a side perspective view from one side of another version of a steam generator according to further aspects of the disclosure;

[0021] FIG. 9 is a side perspective view from an opposite side of the steam generator shown in FIG. 7;

[0022] FIG. 10 is a side perspective, exploded view of the steam generator shown in FIG. 7;

[0023] FIG. 11 is a cross-sectional view taken along section line 11-11 of FIG. 9;

[0024] FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG. 9.

[0025] FIG. 13 is a side perspective view of another version of a steam generator according to further aspects of the disclosure;

[0026] FIG. 14 is a side perspective, exploded view of the steam generator shown in FIG. 13;

[0027] FIG. 15 is a cross-sectional view taken along section line 15-15 of FIG. 13;

[0028] FIG. 16 is a cross-sectional view taken along section line 16-16 of FIG. 13;

[0029] FIG. 17 is a cross-sectional view taken along section line 17-17 of FIG. 13;

[0030] FIG. 17A is an alternate version of the steam generator shown in FIG. 13 including stacked steam generators;

[0031] FIG. 17B is a side cross-sectional view taken along section line 17B-17B of FIG. 17A;

[0032] FIG. 18 is a side perspective view of another version of a steam generator according to further aspects of the disclosure;

[0033] FIG. 19 is a side perspective, exploded view of the steam generator shown in FIG. 18;

[0034] FIG. 20 is an electrode array of the steam generator shown in FIG. 20;

[0035] FIG. 21 is an enlarged view of the indicated area of detail shown in FIG. 18;

[0036] FIG. 22 is a cross-sectional view taken along section line 22-22 of FIG. 18; and

[0037] FIG. 23 is a cross-sectional view taken along section line 23-23 of FIG. 22.DETAILED DESCRIPTION

[0038] Although illustrative systems of this disclosure will be described in terms of specific aspects, it will be readily apparent to those skilled in this art that various modifications, rearrangements, and substitutions may be made without departing from the spirit of this disclosure.

[0039] For purposes of promoting an understanding of the principles of this disclosure, reference will now be made to exemplary aspects illustrated in the figures, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended. Any alterations and further modifications of this disclosure features illustrated herein, and any additional applications of the principles of this disclosure as illustrated herein, which would occur to one skilled in the relevant art having possession of this disclosure, are to be considered within the scope of this disclosure.

[0040] A steam or vapor generator 200 in accordance with aspects of the disclosure is depicted in FIGS. 2 and 3. The steam generator 200 includes a steam or vapor outlet 201, one or more electrode contacts 202 (of which there are four depicted), electrodes 206 (of which there are also four depicted) in electrical communication with the respective electrode contacts 202, a top cap 203, a body 204, and a water inlet 205. The steam generator 200 can also have a drain 218 positioned at the bottom of the body 204 to facilitate drainage of water after use.

[0041] As shown in FIG. 4, the top cap 203 includes receptacles 208 for receiving respective tabs 210 extending upwardly at the top of each electrode 206. In aspects of the disclosure, each of the electrodes 206 is in the form of a conductive plate with two planar faces 206a. The receptacles 208 include a wider relief portion 212 for receiving the respective electrode contacts 202 therein while the electrode contacts 202 receive the tabs 210 of the electrodes 206. Specifically, each electrode contact 202 may be in the form of a resilient wire having a lower end bent into the shape of a clip 214 by having two opposed portions of the wire define a gap 213 (FIG. 4) therebetween. Such gap 213 is sized based on the thickness of the tabs 210 of the electrodes 206, such that the tab 210 can be slid into the gap while the clip 214 maintains a stable electrical connection to the electrode 206 (e.g., by having the clip 214 deflect slightly upon receiving the tab 210 therein). An example of a wireform that can be used to form the electrode contacts 202 herein is disclosed in U.S. Pat. No. 12,156,624, issued on Dec. 3, 2024, the disclosure of which is incorporated herein by reference.

[0042] When assembled, the top cap 203 is secured on top of the body 204, to collectively define a housing 215 for the electrodes 206. The electrodes 206 are contained within an interior chamber 215a defined within the housing 215. Within the body 204, one or more feeder channels 207 (FIG. 5) are provided along the perimeter of the interior chamber 215a such that the feeder channels 207 extend transverse to planes defined by the planar faces 206a of the electrodes 206. As shown in FIG. 5, two of such feeder channels 207 may be provided along opposing corners of the interior chamber 215a to extend past the perimeters of the electrodes 206, to allow water in the liquidous phase to feed channels or open spaces 216 (FIG. 4) between the planar faces 206a of each adjacent pair of electrodes 206. Such channels or open spaces 216 are defined by the opposing electrode planar faces 206a in one dimension, whereas the other two dimensions are enveloped by the housing 215 defined by the top cap 203 and the body 204.

[0043] In some aspects of the disclosure, the steam generator 200 includes an annular spacer 270 (FIG. 5) that is positioned between the upper end of the body 204 of the steam generator 200 and the top cap 203. The spacer 270 presses against a gasket or insulator 272 that is positioned on an inner surface of the top cap 203 to hold the insulator 272 in place. The insulator 272 insulates the electrodes 206 from the contacts 202 to minimize corrosion. More specifically, where the contacts 202 are formed from phosphor bronze material and the electrodes 206 are formed from graphite, the contacts 202 may corrode in the presence of an electric field. The tabs 210 of the electrodes 206 extend through the insulator 272 to insulate the contacts 202 from the electric field produced by the electrodes 206 and minimize any likelihood of corrosion.

[0044] In operation, hot water from the separate water boiler of a coffee apparatus is introduced to the water inlet 205. The water is allowed to distribute along the channels or open spaces 216 via the one or more feeder channels 207. Electrical power is supplied to the electrodes 206 to bring the temperature of the water to the vapor point, and then to vaporize the liquid into gas, i.e. steam. In aspects of the disclosure, an upper end of at least some of the electrodes 206 defines a cutout 206b (FIG. 7) to define a steam chamber 209 within the housing 215.

[0045] The power required during operation of the steam generator 200 to heat the water so as to generate steam can be broken into two parts. The first part is the heating power required to bring the hot water to the boiling point, which is given by the following equation:q.1=m.⁢ cp⁢ Δ⁢T(Equation⁢ 1)Where:

[0047] {dot over (q)}1 is the heating power to effect temperature increase;

[0048] {dot over (m)} is the mass flow rate;

[0049] cp is the specific heat of water; and

[0050] ΔT is the temperature change from inlet temperature to boiling.

[0051] The second part is the heating power to change the phase of the water from liquid to gas (steam), which is given by the following equation:q.2=m.⁢ Δ⁢ Hvap⁢ X(Equation⁢ 2)Where:

[0053] {dot over (q)}2 is the heating power of vaporization; and

[0054] ΔHvap is the enthalpy (heat) of vaporization.

[0055] X is the ratio of the mass of vapor to the total mass of the fluid.

[0056] Typically, the heat of vaporization is much larger than the heat required to effect an increase in water temperature. The steam generator 200 is designed to operate at a steady state, so that the supplied heating power in electrical power balances the mass flow rate.

[0057] The heat to effect the temperature increase utilizes Ohmic heating where the electrical current passes through the liquid water. The electrical resistance of the water, based upon the intrinsic resistivity, gives rise to a Joule heating effect. Once the liquid begins to change phase, however, the effective circuit is interrupted. During this mixed phase heating is where the majority of the power is expended.

[0058] The mixed phase consists of both liquid and gas. The liquid has much higher intrinsic conductivity than the gas. In fact, the gas conductivity is treated as zero, so that all the current is passed through the liquid constituent of the mixture. The nature of this mixed phase regime can be thought of as a network of bubbles, where the interior of each bubble consists of gas, and the walls are liquid. This requires the electrode surfaces to be designed to have sufficient surface area to use the bubble walls only for the transition to vapor.

[0059] The size of the bubbles is subject to the applied pressure, according to Boyle's law; as pressure increases the volume of the bubble decreases. Since the interior of the bubble is non-conductive, that means the conductance of the mixture increases with applied pressure. The pressure at steady state flow is due to the resistance in a steam wand, which may or may not be supplemented with additional restrictors. The resistance causes back pressure within the steam generator 200.

[0060] The steam generator 200 is intended to operate at a fixed flow rate, for example 1 liter of steam per second. Further, the pressure and temperature are set to be consistent with conventional steam boilers widely used in coffee machines. Combining these factors produces a steam generator 200 that is far smaller than conventional boilers, such as those utilizing electrical resistance heating. In view of that reduced size, as well as other benefits as discussed above (including lower heat loss, only providing heat when required, lower susceptibility to scale buildup), a steam generator 200 in accordance with the present disclosure may be designed to be retrofitted into existing hot beverage apparatuses, such as commercial coffee machines, by replacing the conventional steam boiler.

[0061] In other aspects, the steam generator 200 disclosed herein may be incorporated into existing coffee machine platforms in place of the conventional steam boilers now used without the need to substantially redesign the platform.

[0062] The design of the components of the steam generator 200 desirably allows for simplicity of manufacture to yield an inherently thermally efficient device. In aspects of the disclosure, the body 204 of the steam generator 200 defines vertical slots 248 positioned on opposite sides of the body 204 that slidably receive and support the ends of the electrodes 206 at fixed positions within the interior chamber 215a of the housing 215. The housing 215, consisting of the cap 203 and the body 204, respectively, is formed of a dielectric material to prevent electrical connections between the electrodes 206 through the housing 215. For example, the housing components can be injection molded from a polymer with very good thermal and electrical insulating properties. The electrode contacts 202, can be formed of wire and the electrodes, 206 may be machined from graphite stock, whereas the inlet and outlet ports 201 and 205 may be standard off-the-shelf commodities. Alternately, other materials of construction are envisioned.

[0063] The assembly of the components of the steam generator 200 is also straightforward, in that electrode contacts 202 are inserted into relief portions 212 in the cap 203, and then the tabs 210 of the electrodes 206 are pushed into the clips 214 of the electrode contacts 202 to form electrical communication between the two. The relief portions 212 may then be filled with pottant. Subsequent to curing of the pottant, the power end cap 203 and the body 204 are assembled together with an O-ring 220 therebetween for sealing and fixed in place with fasteners 222 (FIG. 6). It is also envisioned that as an alternative to using pottant, the insulator 272 (FIG. 5) can be used to insulate the contacts 202 from the electric field produced by the electrodes 206 and minimize any likelihood of corrosion.

[0064] In some aspects of the disclosure, the control of the electrical power to the steam generator 200 to transfer sufficient heating energy to the water is achieved by way of selected excitation of combinations of the electrodes 206. Examples of control methodologies and circuitry that can be employed include those disclosed in U.S. Pat. Nos. 7,817,906; 10,365,013; 11,353,241; and International Patent Pub. No. WO 2023 / 158814, the disclosures of all of which are incorporated herein by reference. In aspects of the disclosure, a Printed Circuit Board Assembly (PCBA), not shown, can be affixed atop the steam generator 200 and would be populated with, amongst other components, switches, such as Triacs, to effect the electrical communication between a power source and each of the electrode contacts 202. The control is somewhat simplified since the flow rate of the hot water as well as the incoming temperature may be fixed. Furthermore, when the water boiler that supplies the hot water to the steam generator 200 is an ohmic water heater, the incoming conductivity of the water may also be known.

[0065] It is envisioned that in the steam generator 200, all the electrodes 206 can be energized simultaneously, such that the system back pressure regulates the rate of energy transfer, i.e., power, within the steam generator 200.

[0066] In some aspects of the disclosure, the steam generator 200 includes four electrodes 206. Alternately, the steam generator 200 may have fewer or more electrodes 206, with variations in the spacing between them. In some aspects of the disclosure, the electrodes 206 are evenly spaced.

[0067] FIG. 6 illustrates a steam or vapor generation system 250, hereinafter steam generation system 250, including the steam generator 200. The steam generator 200 accepts water from a water boiler 230 and outputs steam to the steam wand 232 or another restrictor. In some aspects of the disclosure, hot water from the water boiler, at high pressure, is delivered via an inlet line 231 to a pressure regulator 233 which is set to a predefined pressure. When the steam generator 200 is activated and the steam generation cycle starts, initially, the pressure within the steam generator 200 is ambient and is lower than the pressure at the outlet of the water heater 230. As such, water from the water heater 230 flows through the pressure regulator 233 and through an orifice or needle valve 234 before being delivered to the steam generator 200. The water is received into the steam generator 200 via the water inlet 205, at which point the water is ready for heating and vaporization. The steam or vapor outlet 201 communicates with a steam valve 236 and then the steam wand 232, which serves to dispense the steam to, for example, froth milk. As steam is generated within the steam generator 200 and delivered to the steam wand 232 which acts like another orifice, back pressure is developed within the steam generator 200. When the back pressure within the steam generator 200 equals the set pressure of the pressure regulator 233, the pressure regulator 233 stops water flowing through the pressure regulator 233 into the steam generator 200. In this state, the system 250 is in equilibrium. As the steam is released or burned off, the back pressure within the steam generator 200 decreases and the pressure regulator 233 re-opens to allow water flow back into the steam generator 200 to create a steady state condition in which the back pressure balances the pressure across the pressure regulator 233 to create a constant flow of steam from the steam generator 200 to the steam wand 232. Since the steam and water within the steam generator 200 are at saturation, regulating the pressure within th system 250 also regulates the temperature.

[0068] In aspects of the disclosure, the steam valve 236 is not required. In some aspects of the disclosure, a pressure sensor 238 is interposed between the steam or vapor outlet 201 and the steam valve 236 for measuring the pressure within the outlet line 240 In some aspects of the disclosure, the needle valve 234 is set so that a specific flow rate is established, and the current delivered to the electrodes 206 is monitored to maintain a constant flow of steam. When the back pressure within the steam generator 200 increases, the electrical power to the electrodes 206 of the steam generator 200 will be switched off.

[0069] The steam generator 200, such as that shown in FIGS. 2-4, can be included in a hot beverage apparatus, such as a coffee machine, where it may be one of two liquid heaters in the apparatus. Specifically, one of the liquid heaters may be a water boiler that is supplied with potable water (e.g., by being supplied by an on-board tank or by being connected to building plumbing supplying potable water), and the second liquid heater can be the steam generator 200. In some aspects of the disclosure, the water boiler of the hot beverage apparatus may utilize ohmic heating technology for heating the water, similar to the steam generator 200. In other aspects of the disclosure, the water boiler may utilize other heating technology, such as more traditional electrical resistance heating elements. The water boiler may include a first outlet for supplying heated water to be dispensed by the hot beverage apparatus. For example, a first outlet may be connected to one or more brew heads, where the hot water can be used to brew coffee or espresso or can simply be dispensed to make hot tea. A second outlet of the water boiler may be connected to the water inlet 205 of the steam generator 200. Moreover, as discussed above, the steam generator 200 may include a steam or vapor outlet 201 connected to a steam or vapor wand 232 or other dispenser on the hot beverage apparatus for dispensing the steam.

[0070] Typical heating temperatures of the two liquid heaters may be in a range of 90° C. to 96° C. for the water boiler and a range of 100° C. to 150° C. for the steam generator 200. Moreover, the vessels for the water boiler and steam generator 200 should be designed to withstand internal pressures on the order of 1.0 bar to 15.0 bar in the case of the water boiler and 1.0 bar to 5.0 bar in the case of the steam generator 200.

[0071] Among the benefits achieved by aspects of the disclosure are the production of steam near-instantaneously; the provision of heat only during the development of steam; and the compactness of the steam generator 200 so as to limit heat loss.

[0072] Although the steam generator 200 and steam generation system 250 have been described with reference to particular aspects of the disclosure, it is to be understood that these aspects are merely illustrative of the principles and applications of the disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative aspects of the disclosure and that other arrangements may be devised without departing from the spirit and scope of the disclosure as defined by the appended claims.

[0073] FIGS. 8-12 illustrate an alternate version of the steam or vapor generator shown generally as steam generator 300. In aspects of disclosure, the steam generator 300 includes a generator base 310, a generator body 312, electrodes 314, an insulator 316, electrode contacts 318, a reservoir base 320, a reservoir body 322, and reservoir cover 324. In aspects of the disclosure, the generator body 312 has a rectangular configuration and the reservoir body 322 has a cylindrical configuration, although other configurations are envisioned. The generator base 310 defines a cavity 326, a liquid inlet 328, and a drain 330, and has a bottom wall 313 that includes or supports electrode support members 332. The support members 332 extend from opposite walls of the generator base 310 toward the center of the generator base 310 and decrease in height towards the center of the generator base 310 to define triangular or trapezoidal recesses 334 (FIG. 12) that receive lower triangular end portions 314a of the electrodes 314. The support members 332 are formed of a dielectric material and define or limit the electric field space defined between the electrodes 206 in the lower portion of the vertical channels 340.

[0074] The liquid inlet 328 is positioned beneath the bottom wall 313 of the cavity 326 and communicates with a pressure plenum 329 that communicates with small diameter orifice ports 336 formed in the bottom wall 313 of the generator base 310 for sub floor distribution of water into the steam generator 300. The orifice ports 336 extend through the bottom wall 313 and communicate with the cavity 326 at positions between each of the electrode support members 332 in the center of the cavity 326. The orifice ports 336 are positioned to deliver water evenly to a lower end of vertical channels 340 (FIG. 11) defined between spaced planar faces 314b of each of the adjacent electrodes 314 and between the electrode support members 332. It is noted that the upper portion of the vertical channels 340, located above lower triangular end portions 314a of the electrodes 314, is defined only by the planar faces 314b of adjacent electrodes 314. In aspects of the disclosure, the steam generator 300 includes four spaced electrodes 314 that define three channels 340 with each of the channels 340 communicating with one of the orifice ports 336. It is envisioned that the steam generator 300 can include two or more electrodes 314 to define one or more channels 340.

[0075] The drain 330 is aligned with the bottom wall 313 of the generator base 310 and facilitates draining of any residual water from within the steam generator 300. This allows the steam generator 300 to be fully drained after use to facilitate startup in a completely dry condition.

[0076] The generator body 312 is secured to the upper surface of the generator base 310 and has inner surfaces 342 that define vertical slots 344 on opposite walls. In aspects of the disclosure, the generator body 312 and the generator base 310 include brackets 348 that are positioned to receive bolts (not shown) to secure the generator base 310 to the generator body 312. Alternately, other types of attachment devices and techniques for coupling the generator base 310 to the generator body 312 are envisioned. The vertical slots 344 are aligned with the electrode support members 332 and slidably receive the electrodes 314 to position the electrodes 314 in sealing engagement with the electrode support members 332 at predetermined spaced locations within the steam generator 300. It is envisioned that the spacings between the electrodes 314 can be the same. Alternately, the spacings between the electrodes 314 can be different to selectively control power delivery within each of the respective channels 340.

[0077] Each of the electrodes 314 has a lower end portions 314a that has a triangular or trapezoidal configuration that increases in width from the bottom of the electrode 314 upwardly towards the top of the electrode 314. It is envisioned that the degree to which lower end portions 314a of the electrodes 314 increase in width may be selected to control the rate of steam formation within the steam generator 300. Although the lower end portions 314a of the electrodes 314 are illustrated as having a triangular configuration, it is envisioned that a substantial portion, or in alternate aspects of the disclosure, the entire electrodes 314 can have a triangular configuration. In some aspects of the disclosure, the angled lower edges of the lower triangular end portion 314a of each of the electrodes 314 with the horizontal axis “H” define an angle β (FIG. 10) of between about 10 degrees and about 55 degrees. In further aspects of the disclosure, the angled lower edges of the lower triangular end portion 314a of each of the electrodes 314 with the horizontal axis “H” define an angle β (FIG. 10) of between about 15 degrees and about 45 degrees.

[0078] The lower end portions 314a of the electrodes 314 are received within the recesses 334 defined by the electrode support members 332 in the generator base 310. The electrode support members 332 are formed of a dielectric material and do not conduct electricity. The trapezoidal or triangular configuration of the lower end portions 314a of the electrodes 314 reduces the area of the electrodes 314 initially exposed to water adjacent the orifice ports 336 to reduce the flow of electrical current through water at the inlet of the channels 340 of the steam generator 300. This reduces the amount of energy delivered to the water at the inlet of the steam generator 300 to slow down the formation of steam in the steam generator 300 when water is first supplied to the channels 340. This reduction in area allows the steam generated within the lower end portions of channels 340 to be gradually pushed upwardly though the channels 340 of the steam generator 300. It also avoids immediate flashing of large volumes of water, and thus large pressure increases within the steam generator 300 that may place control circuitry of the steam generator 300 into oscillation, i.e., the switching behavior of the control circuitry becomes unstable and may be subject to rapid back and forth switching between states.

[0079] Each of the electrodes 314 includes a tab 350 that extends through a slot 352 defined in a respective insulator 316 into engagement with one of the electrical contacts 318. The insulators 316 shield the interface between the electrical contacts 318 and the tabs 350 of the electrodes 314 from the electrical field to minimize corrosion. The electrical contacts 318 can be configured in the form of a clip 319 as described above regarding electrical contact 214 (FIG. 4) to maintain the electrical contacts 318 engaged with the electrodes 314. The electrodes 314 are secured to the electrode contacts 316 to facilitate delivery of electrical power to the electrodes 314. The control of electrical power to the steam generator 300 to transfer sufficient heating energy to the water is achieved by way of selected excitation of combinations of the electrodes 314 as described above regarding steam generator 200.

[0080] The reservoir base 320 is secured to the upper surface of the generator body 312. In aspects of the disclosure, the reservoir base 320 is secured to the top of the generator body 312 using any known attachment device including bolts, welds or the like. In aspects of the disclosure, reservoir base 320 defines a steam opening 360 that extends through the reservoir base 320 and allows steam to flow upwardly from the generator body 312 and into the reservoir body 322. In some aspects of the disclosure, the steam opening 360 is circumscribed by a downwardly angled wall 362 that directs any condensation in the reservoir body 322 to flow into the generator base 310 where the water can exit the generator base 310 through the drain 330. The reservoir base 320, the reservoir body 322, and the reservoir cover 324 define a steam reservoir 380 for collecting steam formed by the generator 300.

[0081] In aspects of the disclosure, the reservoir body 322 has a cylindrical configuration and receives a cylindrical portion 320a of the reservoir base 320 and a cylindrical portion 324a of the reservoir cover 324 to couple the reservoir base 320 and the reservoir cover 324 to the reservoir body 322. In some aspects of the disclosure, the cylindrical portions 320a and 324a of the reservoir base 320 and the reservoir cover 324, respectively, define annular recesses that receive O-rings 364 and 366, respectively. Although not shown, the reservoir base 320, the reservoir body 322, and the cover 324 can be secured together using elongate bolts and screws (not shown) that are received within screw holes 370 (FIG. 11) formed in the reservoir base 320 and the reservoir cover 324.

[0082] The components of the steam generator 300, excluding the electrodes 314, the electrode contacts 316, and the conductors 318, can be formed of a dielectric material to prevent electrical connections between the electrodes 314 through the generator base 310 and generator body 312. In some aspects of the disclosure, the components can be injection molded from a polymer with very good thermal and electrical insulating properties. The electrode contacts 316 can be formed of a conductive material such as brass, the conductors 318 can be formed of wire, and the electrodes 314 may be machined from graphite stock. In some aspects of the disclosure, the electrodes can be formed from stainless steel or titanium. In further aspects of the disclosure, the electrodes can be formed from titanium with a plating of, e.g., ruthenium (Ru) and iridium (Ir).

[0083] In use, heated water is supplied from a source, e.g., a water main or a second water heater or boiler, into the liquid inlet 328 of the steam generator 300. Water flows from the liquid inlet 328 into the pressure plenum 329 where the water is evenly distributed through the orifice ports 336 into the channels 340 defined between the planar faces 314b of the adjacent electrodes 314. As the water passes from the orifice ports 336 into the channels 340, the water is exposed to the small portion of the area of the electrodes 314 within the channels 340 defined by the electrodes 314 and is heated to its boiling point and vaporized. The steam moves upwardly through the channels 340 and flows through the steam opening 360 into the steam reservoir 380.

[0084] In aspects of the disclosure, the reservoir cover 324 defines an outlet port 382. The outlet port 382 can be coupled to a steam wand, e.g. steam wand 232 (FIG. 6), to froth milk as described above. Although not shown, the steam generator 300 can be incorporated into a steam generation system such as steam generation system 250.

[0085] FIGS. 13-17 illustrate an alternate version of a steam or vapor generator according to aspects of the disclosure shown generally as steam generator 400. Steam generator 400 includes a generator base 410, a generator body 412, electrodes 414, insulators 416, electrical contacts 418, and a cover 420. In aspects of the disclosure, the generator body 412, the generator base 410, and the generator cover 420 have cylindrical configurations, although other configurations are envisioned. The generator base 410 includes a bottom wall 422 that defines a cavity or recess 426 that converges downwardly from an outer periphery 424 of the generator base 410 towards a central portion 425 of the bottom wall 422 of the generator base 410. In some aspects of the disclosure, the bottom wall 422 defines a semi-spherical concavity. The generator base 410 also defines a liquid inlet 428 (FIG. 15) and a drain outlet 430. The liquid inlet 428 and the drain outlet 430 are adapted to receive fittings 428a and 430a, respectively, to facilitate coupling of the steam generator to other components of a steam generation system, e,g., steam generation system 250 (FIG. 6). The bottom wall 422 of the generator base 410 defines a plurality of spaced slots 434 that extend across the generator base 410 from the outer periphery 424 downwardly through the central portion 425 of the generator base 410.

[0086] The generator body 412 is supported on the generator base 410 and includes an inner wall 436 that defines a cavity 438 that contains the electrodes 414 and forms a steam reservoir 442 that is positioned on opposite sides of the electrodes 414. The inner wall 436 of the generator body 412, or a structure supported on the inner wall 436, defines a plurality of pairs of diametrically opposed vertical slots 444. Each of the pairs of vertical slots 444 is aligned with a respective one of the slots 434 in the bottom wall 422 of the generator base 410 such that each of the electrodes 414 is received and supported within one of the pairs of vertical slots 444 and one of the slots 434. Placement of the electrodes 414 in the slots 434 and 444 retains the electrodes 414 at spaced positions within the cavity 438 to define a plurality of channels 448 between the planar faces 414b of the electrodes 414 for the formation and passage of steam.

[0087] Each of the electrodes 414 has a lower end portion 414a that has a triangular or trapezoidal configuration that increases in width from the bottom of the electrode 414 upwardly towards the top of the electrode 414. It is envisioned that the degree to which lower end portions 414a of the electrodes 414 increase in width may be selected to control or regulate the initial rate of steam formation in the steam generator 400. Although the triangular portions of the electrodes 414 are illustrated as being confined to the lower end portions 414a of the electrodes 414, it is envisioned that a substantial portion, or in alternate aspects of the disclosure, the entire electrode 414 can have a triangular configuration. In some aspects of the disclosure, the angled lower edges of the lower triangular end portion 314a of each of the electrodes 314 with a horizontal axis “H” define an angle β (FIG. 10) of between about 10 degrees and about 55 degrees. In further aspects of the disclosure, the angled lower edges of the lower triangular end portion 314a of each of the electrodes 314 with a horizontal axis “H” define an angle β (FIG. 10) of between about 15 degrees and about 45 degrees.

[0088] Each of the electrodes 414 includes a tab 450 that extends through a slot 452 defined in a respective insulator 416 into engagement with one of the electrical contacts 418. The insulators 416 shield the interface between the electrical contacts 418 and the tabs 450 of the electrodes 414 from the electrical field adjacent the electrodes 414 to minimize corrosion. The electrical contacts 418 can be configured in the form of a clip 419 as described above regarding electrical contact 214 (FIG. 4) to maintain the electrical contacts 418 engaged with the electrodes 414. The electrodes 414 are secured to the electrode contacts 418 to facilitate delivery of electrical power to the electrodes 414. The control of electrical power to the steam generator 300 to transfer sufficient heating energy to the water is achieved by way of selected excitation of combinations of the electrodes 414 as described above regarding steam generators 200 and 300.

[0089] The liquid inlet 428 is positioned beneath the bottom wall 422 of the generator base 410 and communicates with a pressure plenum 429 (FIG. 17). The pressure plenum 429 has a diameter that is smaller than the diameter of the liquid inlet 428 and communicates with small diameter orifice ports 456 formed in the central portion 425 of the bottom wall 422 of the generator base 410 for sub floor distribution of water into the steam generator 400. Each of the orifice ports 456 extends through the central portion 425 of the bottom wall 422 to deliver water evenly to the lower end portions of the vertical channels 440 defined between the planar faces 414b of each of the adjacent electrodes 414. In aspects of the disclosure, the steam generator 400 includes four spaced electrodes 414 that define three channels 440 with each of the channels 440 communicating with one of the orifice ports 456. It is envisioned that the steam generator 400 can include two or more electrodes 414 to define one or more channels 440.

[0090] The drain outlet 430 (FIG. 17) is positioned below the bottom wall 422 of the generator base 410 and communicates with an opening 460 in the bottom wall 422 via a drain channel 462 that extends upwardly through the bottom wall 422 at a position adjacent the central portion 425 of the generator base 410. The drain outlet 430 facilitates draining of any residual water from within the steam generator 400 to facilitate start-up of the steam generator 400 in a completely dry condition.

[0091] The lower triangular end portions 414a of the electrodes 414 are received within the slots 434 in the bottom wall 422 of the generator base 410 such that the portions of the electrodes 414 adjacent the apex 470 (FIG. 16) of the lower end portions 414a are received within the central portion 425 of the bottom wall 422 at a location adjacent the orifice ports 456. The trapezoidal or triangular configuration of the lower end portions 414a of the electrodes 414 reduces the area of the electrodes 414 exposed to water adjacent the orifice ports 456 to initially limit the flow of electrical current into the water at the inlet of the steam generator 400. This reduces the amount of energy delivered to water at the inlet of the steam generator 400 to slow down the rate of formation of steam in the steam generator 400 when water is first supplied to the channels 440 to allow the steam generated to be gradually pushed upwardly though the steam generator 400. It also avoids immediate flashing of the water, and thus large pressure increases within the steam generator 400 that may place control circuitry of the steam generator 400 into oscillation as described above.

[0092] The generator body 412 of the steam generator 400 defines a steam or vapor outlet 480 (FIG. 17) that is positioned on one side of the steam generator 400 and communicates with the steam reservoir 442. In aspects of the disclosure, the steam or vapor outlet 480 is adapted to receive a fixture 480a to facilitate coupling of the steam or vapor outlet 480 to a steam generation system, e.g., steam generation system 250 (FIG. 6).

[0093] In aspects of the disclosure, the generator cover 420 is secured to the upper end of the generator body 412 and includes an interior surface 483 that is positioned above and spaced from the electrodes 414 to allow steam to flow over the upper ends of the electrodes 414. In some aspects of the disclosure, the inner surface of the generator cover 420 has a concave, semi-spherical configuration that directs steam outwardly of the electrode array 484 formed by the electrodes 414. In some aspects of the disclosure, the generator base 410 and the generator cover 420 define annular grooves 486a and 488a that receive O-rings 486 and 488, respectively, to seal between the generator body 412 and the generator base and cover 410 and 420, respectively.

[0094] FIGS. 17A and 17B illustrate a steam or vapor generator 500 that includes a first steam generator 500A and second steam generator 500B configured in a stacked orientation. Each of the steam generators 500A and 500B are substantially similar to the steam generator 400 described above but are secured together in stacked relation. More specifically, each of the steam generators 500A and 500B includes a generator body 512A and 512B, electrodes 514A and 514B, a liquid inlet 528A and 528B, a drain outlet 530A and 530B, and a steam or vapor outlet 580A and 580B. The steam generator 500A includes a generator base 510A and the steam generator 500B includes a generator cover 520B. The steam generators 500A and 500B differ from the steam generator 400 as described above in that the steam generators 500A and 500B share a central generator plate 530 that functions as the generator cover for the steam generator 500A and as the generator base for the steam generator 500B. More specifically, the central generator plate 530 includes a liquid inlet 528B and a drain 530B for the steam generator 500B, and a generator cover 520A for the steam generator 500A. All of the components of the steam generators 500A and 500B function as described above regarding steam generator 400 and will not be described in further detail herein.

[0095] FIGS. 18-23 illustrate another alternate version of a steam or vapor generator according to aspects of the disclosure shown generally as steam generator 600. FIG. 18 illustrates a perspective view of the steam generator 600 which includes a lower end cap 610, a generator body 612, an upper end cap 614, and threaded bolts 616. The lower and upper end caps 610 and 612, and the generator body 612 together form a housing 617 of the steam generator 100. It is envisioned that the lower end cap 610 or the upper end cap 614 could be formed integrally with the generator body 612.

[0096] In aspects of the disclosure, the generator body 612 has a cylindrical configuration and defines a cavity 620 (FIG. 19) that receives internal components of the steam generator 600 described below. In some aspects of the disclosure, the generator body 612 has open lower and upper ends that are enclosed by the lower end cap 610 and the upper end cap 614, respectively. In certain aspects of the disclosure, the upper end cap 614 defines through bores 622 that are aligned with respective through bores 624 defined in the lower end cap 610, and the bolts 616 are received through the through bores 622 and 624 to secure the lower end cap 610 and upper end cap 614 to the lower and upper ends of the generator body 612. It is envisioned that threaded nuts 628 (FIG. 19) could be used to secure the bolts 626 to the lower end cap 610 and to the upper end cap 614. Alternately, it is envisioned that the through bores 622 and / or 624 could be threaded.

[0097] FIG. 19 illustrates an exploded view of the steam generator 600 illustrating the internal components of the steam generator 600 which in some aspects of the disclosure include a steam generator core 632, an upper O-ring 634, a lower O-ring 636, a plurality of conductors 638, a plurality of electrical contacts 640, and a plurality of nuts 642 and washers 644. The upper O-ring 634 (FIG. 22) is positioned within an annular slot 646 formed in the inner surface of the upper end plate 614 to provide a seal between the upper end plate 614 and the upper end of the generator body 612, and the lower O-ring 636 (FIG. 22) is positioned within an annular slot 648 formed in the inner surface of the lower end plate 610 to provide a seal between the lower end plate 610 and the lower end of the generator body 612.

[0098] FIG. 20 illustrates the steam generator core 632 which includes an alternating stack of spacers 650a-d and electrodes 652a-e, a retainer member 654, a base plate 656, and a cover plate 659. The steam generator core 632 is received within the cavity 620 (FIG. 19) of the generator body 612 with the base plate 656 positioned atop the lower end cap 610, the cover plate 659 positioned below the upper end cap 614, and the retainer member 654 positioned between the cover plate 659 and the stack of spacers 650a-d and electrodes 652a-e. In aspects of the disclosure, a void 661 (FIG. 22) is defined between the cover plate 659 and the upper end plate 614. The void 661 is positioned to capture stray water droplets that may be found in the steam flow as the steam exits the steam generator 600 through the steam or vapor outlet 666.

[0099] The retainer member 654 is formed of a dielectric material and has a cylindrical configuration to maintain separation between the cover plate 659 and the uppermost electrode 652e and to define a steam reservoir 672 within the cavity 620. In aspects of the disclosure, the retainer member 654 includes cutouts 674 that are angularly offset from each other about the retainer member 654. The cutouts 674 reduce the amount of material required to manufacture the retainer member 654 to minimize cost.

[0100] Each of the spacers 650 is formed of a dielectric material and is positioned between confronting planar faces 653 of each two adjacent electrodes 652a-e of the electrodes 652a-e. In aspects of the disclosure, the spacers 650 have a cylindrical configuration and engage the outer peripheries of the electrodes 652a-e in sealing or fluid-tight fashion to define vertically spaced fluid chambers 658a-d (FIG. 22) within the steam generator core 632. The electrodes 652a-e are arranged in stacked, spaced relation to each other and have a main axis “X” that is perpendicular to a vertical axis “V” (FIG. 22) defined by the steam generator 600.

[0101] The lower end cap 610 defines a liquid inlet 664 and the upper end cap 614 defines a steam or vapor outlet 666. The liquid inlet 664 communicates with the lowermost fluid chamber 658a of the steam generator 600 via a bore 668 defined in the base plate 656 to deliver fluid into the fluid chamber 658a. In aspects of the disclosure, the liquid inlet 664 is centrally located in the lower end cap 610 and the bore 668 is centrally located in the base plate 656. In further aspects of the disclosure, the steam or vapor outlet 666 is also centrally located in the upper end cap 614 and is vertically aligned with a bore 669 formed in the cover plate 659 and the liquid inlet 664. Alternately, other configurations are envisioned.

[0102] Each of the electrodes 652a-e defines a plurality of openings or chimneys 670 that extend through the electrodes 652a-e to allow fluid, e.g., water, steam, or a mixture of water and steam, to flow upwardly and sequentially from the fluid chamber 658a to the fluid chamber 658b, then to the fluid chamber 658c, and finally to the fluid chamber 658d. The fluid in fluid chamber 658d can flow through the chimneys 670 in electrode 652e into the steam reservoir 672 defined in-part by the retainer member 654.

[0103] In aspects of the disclosure, the chimneys 670 in each of the electrodes 652a-e are aligned with the chimneys 670 in the other electrodes 652a-e such that the chimneys 670 define a series of vertical flow paths 676 (FIG. 22) that extend from the fluid chamber 658a into the steam reservoir 672. The vertical flow paths 676 allow steam bubbles to flow through the electrodes 652a-e along a straight path into the steam reservoir 672. In some aspects of the disclosure, each of the electrodes 652a-e includes a centrally located chimney 670c that is aligned with the liquid inlet 664 and the steam or vapor outlet 666 along the vertical axis “V” (FIG. 22).

[0104] In some aspects of the disclosure, each of the chimneys 670 has a diameter from about 4 mm to about 10 mm, and the chimneys 670 are equally spaced from each other about the electrodes 652a-e. In certain aspects of the disclosure, the diameter of each of the chimneys 670 is from about 6 mm to about 8 mm. In certain aspects of the disclosure, the chimneys 670 are positioned in one or more circular patterns or arrays radially outwardly of the centrally located chimney 670c. In some aspects of the disclosure, each of the electrodes 652a-e includes chimneys 670 in two circular arrays positioned radially outwardly of the centrally located chimney 670c, wherein the circular arrays are positioned at two different radii. Each circular pattern of chimneys 670 can include two or more equally spaced chimneys 670, e.g., six chimneys. In some aspects of the disclosure, the diameter of the chimneys 670 in each of the electrodes 652a-e is substantially the same. Alternately, the diameter of the chimneys 670 can be different from electrode 652a to electrode 652e. For example, the diameter of the chimneys 670 could increase sequentially from the lowermost electrode 652a towards the uppermost electrode 652e, or only between two of the electrodes of the electrodes 652a-e.

[0105] The steam generator 600 includes conductors 638 and electrical contacts 640 to electrically couple a power supply to the electrodes 652a-e. It is envisioned that the electrical conductors 638 and the electrical contacts 640 could be integrally formed as described above, e.g., electrical contacts 418 (FIG. 14). In some aspects of the disclosure, each of the conductors 638 is in the form of a bolt (FIG. 19) having a threaded shaft 680 and a head 682, and each of the electrical contacts 640 is in the form of a leaf spring contact 684. The leaf spring contact 684 defines an opening 686 and includes a bend 688. Each of the threaded shafts 680 of the conductors 638 is received through the opening 686 of a respective one of the electrical contacts 640 and through an opening 690 (FIG. 19) formed in the generator body 612. The head 682 of the conductor 638 is larger than the opening 686 in the electrical contact 640 such that the head 682 of the conductor 638 secures or clamps one end of the electrical contact 640 to the inner surface of the generator body 612. In aspects of the disclosure, the threaded shaft 680 of each of the conductors 638 receives a nut 642 and a pair of washers 644 to secure each conductor 638 and the electrical contact 640 to the generator body 612. In certain aspects of the disclosure, the pair of washers 644 can be formed as a single component. The bend 688 of each of the electrical contacts 640 is angled towards a respective electrode 652a-e to maintain engagement between the electrical contacts 640. In certain aspects of the disclosure, the electrical contacts 640 are formed of a spring-like conductive material, e.g., spring steel, titanium and titanium alloys, beryllium copper, etc., that are elastically deformed when engaged with the electrodes 652a-e to maintain contact between the electrical contacts 640 and the electrodes 652a-e.

[0106] In use, water, which can be preheated, is delivered through the liquid inlet 666 in the central portion of the lower end cap 610 into the lowermost fluid chamber 658a of the steam generator 600 between the electrodes 652a and 652b. When the fluid chamber 658a fills with water, electricity is conducted between the electrodes 652a and 652b to heat and boil the water and generate steam. The change of state of the water from liquid to vapor causes a dramatic increase in volume of fluid within the steam generator 600 causing the water / steam mixture to flow upwardly or “percolate” within the steam generator 600 into the upper fluid chambers 658b-d and subsequently into the steam reservoir 672. As the upper fluid chambers 658b-d fill with fluid, additional electricity flows through electrode pairs 653b and 652c, 652c and 652d, and 652d and 652e, to heat the fluid within the upper fluid chambers 658b, 658c, and 658d, respectively, to generate steam.

[0107] As described above with regard to steam generators 200, 300, 400, and 500, the steam generator 600 can be incorporated into a steam generation system such as steam generation system 250 (FIG. 6).

[0108] Although the steam generators 200, 300, 400, 500, and 600 are described only in regard to heating water to generate steam, it is envisioned that the steam generators 200, 300, 400, 500, and 600 could be used to vaporize other liquids.

[0109] As described above regarding steam generator 200, a PCBA, not shown, can be affixed to or electrically coupled to the steam generators 300, 400, 500A, 500B, and 600 and can be populated with, amongst other components, switches, such as Triacs, to effect the electrical communication between a power source and each of the electrode contacts 318, 418, 640. In aspects of the disclosure, rather than receiving control signals, the PCBA can include components that provide control functionality to provide power to the electrodes to operate the steam generator. This PCBA may include various electrical components, such as power management circuitry, sensing circuitry, relay or switching circuitry, one more controller(s), one or more memory, and / or communication circuitry, among other possible components.

[0110] In some aspects of the disclosure, the PCBA may include power management circuitry which manages voltage and / or current, such as AC / DC converters, step-up converters, step-down converters, and / or waveform shaping circuitry (e.g., pulse width modulation circuitry), among other possibilities.

[0111] In further aspects of the disclosure, the PCBA may include sensing circuitry such as voltage sensors, current sensors, and / or circuitry that interfaces with sensors in the steam generator, such as circuitry that interfaces with temperature sensors in the steam generator, for example. The sensing circuitry may include, for example, amplifiers and / or analog-to-digital converters, among other possibilities.

[0112] In aspects of the disclosure, the PCBA may include relay or switching circuitry such as switches that connect and disconnect power to various of the electrodes. In some aspects of the disclosure, the relay or switching circuitry may include switches that connect to different electrical potentials from a power source. The relay or switching circuitry may include solid-state switches, among other possibilities.

[0113] In aspects of the disclosure, the PCBA may include one or more controller(s), which may include any type of device that can provide control and / or computing functionality, such as microcontrollers, microprocessors, central processing units, and / or digital signal processors, among other possibilities. In aspects of the disclosure, the controller(s) may include and may execute firmware instructions. In aspects of the disclosure, the controller(s) may execute machine-readable instructions accessed from the one or more memories, which may include volatile memory (e.g., random access memory, etc.) and / or non-volatile memory (e.g., EEPROM, etc.). The machine-readable instructions may implement control functionality, such as controlling operations of the steam generator. In aspects of the disclosure, the control functionality may connect power to various of the electrodes at various times according to a predetermined operation. In aspects of the disclosure, the control functionality may process sensing signals provided by the sensing circuitry to perform various computations and may connect power to various of the electrodes based on the computations. For example, the one or more controller(s) may operate to direct power to various of the electrodes in different cycles. As another example, the controller(s) may receive an input reflective of a set point temperature and receive sensing signals reflective of measured temperatures in the steam generator. The controller may direct or not direct power to various of the electrodes based on the set point temperature and the sensing signals reflective of the measured temperatures. Various other operations are described below herein. All such operations are contemplated to be within the scope of the present disclosure.

[0114] In aspects of the disclosure, the PCBA may include communication circuitry, such as wireless communication circuitry enabling communication using technologies such as Wi-Fi, Bluetooth, and / or cellular communications, among other wireless communication technologies. In aspects of the disclosure, the communication circuitry may communicate with a user device, such as a smartphone, tablet, or other user device. In aspects of the disclosure, the communication circuitry may transmit information to and / or receive information from a cloud system. The information communicated by the communication circuitry may be used in various ways, such as used by a user app to control operation of the steam generator and / or to view performance of the steam generator, or use to update firmware within the generator, among other possibilities. Such and other aspects of the disclosure are contemplated to be within the scope of the disclosure.

[0115] In aspects of the disclosure, the control circuitry, e.g., the PCBA is not supported on the steam generator but rather power is supplied to the electrodes of the steam generator via a power line or cable (not shown). In such cases, the power line or cable can be coupled to the electrical contacts and ultimately to the electrodes with conductors that are connected to each of the electrical contacts.

[0116] Further aspects are provided by the subject matter of the following clauses:

[0117] A steam generator comprising: a housing having an upper end and a lower end and defining a cavity, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing; and a generator core received within the cavity, the generator core including a plurality of spacers and a plurality of electrodes, each of the plurality of spacers formed of a dielectric material and positioned between two adjacent electrodes of the plurality of electrodes to define a plurality of vertically spaced fluid chambers including a lowermost fluid chamber and an uppermost fluid chamber, wherein each of the plurality of electrodes defines a plurality of openings, each of the openings of the plurality of openings in each of the electrodes of the plurality of electrodes being aligned along vertical axes with respective openings of the plurality of openings in each of the other electrodes of the plurality of electrodes.

[0118] The steam generator according to any other clause, wherein the liquid inlet is aligned with the vapor outlet along a first vertical axis.

[0119] The steam generator according to any other clause, wherein each opening of the plurality of openings of each electrode of the plurality of electrodes has a diameter of from about 4 mm to about 10 mm.

[0120] The steam generator according to any other clause, wherein each opening of the plurality of openings in each of the plurality of electrodes is spaced equidistant from adjacent openings of the plurality of openings in each of the electrodes.

[0121] The steam generator according to any other clause, wherein one opening of the plurality of openings of each of the electrodes of the plurality of electrodes is aligned with the water inlet and the vapor outlet along the first vertical axis.

[0122] The steam generator according to any other clause, wherein the plurality of openings of each electrode of the plurality of electrodes includes a first circular array of openings.

[0123] The steam generator according to any other clause, wherein the plurality of openings of each electrode of the plurality of electrodes includes a second circular array of openings positioned about the first circular array of openings.

[0124] The steam generator according to any other clause, wherein the generator core includes a base plate, the base plate formed of a dielectric material and supporting a lowermost electrode of the plurality of electrodes.

[0125] The steam generator according to any other clause, wherein the generator core includes a cover plate, the cover plate formed of a dielectric material and positioned above the uppermost electrode of the plurality of electrodes.

[0126] The steam generator according to any other clause, wherein the generator core includes a retainer member positioned between the cover plate and the uppermost electrode of the plurality of electrodes, the retainer member formed of a dielectric material and forming a steam reservoir between the cover plate and the uppermost electrode of the plurality of electrodes.

[0127] The steam generator according to any other clause, wherein each of the base plate and the cover plate defines a bore that is aligned with the liquid inlet and the vapor outlet along the vertical axis.

[0128] A steam generator comprising: a housing having an upper end and a lower end and defining a cavity having a vertical axis, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing; and a generator core received within the cavity, the generator core including a plurality of spacers and a plurality of electrodes, each of the plurality of spacers formed of a dielectric material and positioned between two adjacent electrodes of the plurality of electrodes to define a plurality of vertically spaced fluid chambers including a lowermost fluid chamber and an uppermost fluid chamber, each of the plurality of electrodes defining a plurality of openings to facilitate fluid flow from the lowermost fluid chamber to the uppermost fluid chamber.

[0129] A steam generator system comprising: an inlet line including a pressure regulator and an orifice, the pressure regulator, configured to maintain water pressure exiting the pressure regulator at a predetermined pressure; a steam generator coupled to the inlet line downstream of the pressure regulator, the steam generator including a water inlet and a vapor outlet; and a steam wand coupled to the vapor outlet of the steam generator; wherein the steam generator includes: a housing having an upper end and a lower end and defining a cavity having a vertical axis, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing; and a generator core received within the cavity, the generator core including a plurality of spacers and a plurality of electrodes, each of the plurality of spacers formed of a dielectric material and positioned between two adjacent electrodes of the plurality of electrodes to define a plurality of vertically spaced fluid chambers including a lowermost fluid chamber and an uppermost fluid chamber, each of the plurality of electrodes defining a plurality of openings to facilitate fluid flow from the lowermost fluid chamber to the uppermost fluid chamber.

[0130] A steam generator comprising: a housing having an upper end and a lower end and defining a cavity, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing, the housing being formed from a dielectric material; a plurality of electrodes secured within the cavity in spaced relation to each other to define fluid channels between adjacent electrodes of the plurality of electrodes, each of the plurality of electrodes having planar faces that define the fluid channels with the planar faces of the adjacent electrodes of the plurality of electrodes, each of the fluid channels extending from the lower end of the housing to the upper end of the housing; an electrode contact connected to each of the plurality of electrodes and extending from the housing, the electrode contacts formed of an electrically conductive material; and an inlet channel defined within the lower end of the housing, the inlet channel communicating with each of the fluid channels.

[0131] The steam generator according to any other clause, wherein the inlet channel includes a feeder channel that extends along a bottom wall of the housing and communicates with each of the fluid channels.

[0132] The steam generator according to any other clause, wherein the inlet channel includes a pressure plenum that communicates with each of the fluid channels via small diameter orifice ports that extend through a bottom wall of the housing.

[0133] The steam generator according to any other clause, wherein at least one of the small diameter orifice ports communicates with each of the fluid channels.

[0134] The steam generator according to any other clause, wherein each of the electrodes of the plurality of electrodes includes a lower end having a triangular configuration, the triangular configuration of each of the lower ends of the plurality of electrodes having an apex that is positioned adjacent to a respective one of the small diameter orifice ports.

[0135] The steam generator according to any other clause, wherein the triangular configuration of the lower ends of each electrode of the plurality of electrodes defines an angle β of from about 10 degrees to about 55 degrees with a horizontal axis.

[0136] The steam generator according to any other clause, wherein the triangular configuration of the lower ends of each electrode of the plurality of electrodes defines an angle β of from about 15 degrees to about 45 degrees with the horizontal axis.

[0137] The steam generator according to any other clause, wherein each electrode of the plurality of electrodes has an upper end defining a cutout, the cutouts of the plurality of electrodes defining a steam chamber within the housing.

[0138] The steam generator according to any other clause, further including a reservoir body secured to the upper end of the housing and defining a steam chamber.

[0139] The steam generator according to any other clause, wherein the reservoir body is secured to a reservoir base, the reservoir base secured to the upper end of the housing.

[0140] The steam generator according to any other clause, wherein the reservoir base defines a steam opening that communicates with the vapor outlet of the housing.

[0141] The steam generator according to any other clause, wherein the steam opening is circumscribed by a downwardly angled wall.

[0142] The steam generator according to any other clause, wherein the plurality of electrodes is centrally positioned within the housing, and the housing defines a steam chamber positioned about the plurality of electrodes.

[0143] The steam generator according to any other clause, further including a second steam generator secured to the steam generator in stacked relation.

[0144] Although the disclosure is directed to particular aspects of a steam generator, it is to be understood that these aspects are merely illustrative of the principles and applications of the disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative aspects and that other arrangements may be devised without departing from the spirit and scope of the disclosure as defined by the appended claims.

Claims

1. A steam generator comprising:a housing having an upper end and a lower end and defining a cavity, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing;a generator core received within the cavity, the generator core including a plurality of spacers and a plurality of electrodes, each of the plurality of spacers formed of a dielectric material and positioned between two adjacent electrodes of the plurality of electrodes to define a plurality of vertically spaced fluid chambers including a lowermost fluid chamber and an uppermost fluid chamber; andwherein each of the plurality of electrodes defines a plurality of openings, each of the openings of the plurality of openings in each of the electrodes of the plurality of electrodes being aligned along vertical axes with respective openings of the plurality of openings in each of the other electrodes of the plurality of electrodes.

2. The steam generator of claim 1, wherein the liquid inlet is aligned with the vapor outlet along a first vertical axis.

3. The steam generator of claim 1, wherein each opening of the plurality of openings of each electrode of the plurality of electrodes has a diameter of from about 4 mm to about 10 mm.

4. The steam generator of claim 1, wherein each opening of the plurality of openings in each of the plurality of electrodes is spaced equidistant from adjacent openings of the plurality of openings in each of the electrodes.

5. The steam generator of claim 2, wherein one opening of the plurality of openings of each of the electrodes of the plurality of electrodes is aligned with the liquid inlet and the vapor outlet along the first vertical axis.

6. The steam generator of claim 1, wherein the plurality of openings of each electrode of the plurality of electrodes includes a first circular array of openings.

7. The steam generator of claim 6, wherein the plurality of openings of each electrode of the plurality of electrodes includes a second circular array of openings positioned about the first circular array of openings.

8. The steam generator of claim 1, wherein the generator core includes a base plate, the base plate formed of a dielectric material and supporting a lowermost electrode of the plurality of electrodes.

9. The steam generator of claim 8, wherein the generator core includes a cover plate, the cover plate formed of a dielectric material and positioned above the uppermost electrode of the plurality of electrodes.

10. The steam generator of claim 9, wherein the generator core includes a retainer member positioned between the cover plate and the uppermost electrode of the plurality of electrodes, the retainer member formed of a dielectric material and forming a steam reservoir between the cover plate and the uppermost electrode of the plurality of electrodes.

11. The steam generator of claim 9, wherein each of the base plate and the cover plate defines a bore that is aligned with the liquid inlet and the vapor outlet along the vertical axis.

12. A steam generator comprising:a housing having an upper end and a lower end and defining a cavity having a vertical axis, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing; anda generator core received within the cavity, the generator core including a plurality of spacers and a plurality of electrodes, each of the plurality of spacers formed of a dielectric material and positioned between two adjacent electrodes of the plurality of electrodes to define a plurality of vertically spaced fluid chambers including a lowermost fluid chamber and an uppermost fluid chamber, each of the plurality of electrodes defining a plurality of openings to facilitate fluid flow from the lowermost fluid chamber to the uppermost fluid chamber.

13. The steam generator of claim 12, wherein each opening of the plurality of openings of each electrode of the plurality of electrodes has a diameter of from about 4 mm to about 10 mm.

14. The steam generator of claim 12, wherein each opening of the plurality of openings in each of the plurality of electrodes is spaced equidistant from adjacent openings of the plurality of openings in each of the electrodes.

15. The steam generator of claim 12, wherein the plurality of openings of each electrode of the plurality of electrodes includes a first circular array of openings.

16. The steam generator of claim 15, wherein the plurality of openings of each electrode of the plurality of electrodes includes a second circular array of openings positioned about the first circular array of openings.

17. The steam generator of claim 12, wherein the generator core includes a base plate, the base plate formed of a dielectric material and supporting a lowermost electrode of the plurality of electrodes.

18. The steam generator of claim 17, wherein the generator core includes a cover plate, the cover plate formed of a dielectric material and positioned above the uppermost electrode of the plurality of electrodes.

19. The steam generator of claim 18, wherein the generator core includes a retainer member positioned between the cover plate and the uppermost electrode of the plurality of electrodes, the retainer member formed of a dielectric material and forming a steam reservoir between the cover plate and the uppermost electrode of the plurality of electrodes.

20. A steam generator system comprising:an inlet line including a pressure regulator and an orifice, the pressure regulator, configured to maintain water pressure exiting the pressure regulator at a predetermined pressure;a steam generator coupled to the inlet line downstream of the pressure regulator, the steam generator including a water inlet and a vapor outlet; anda steam wand coupled to the vapor outlet of the steam generator;wherein the steam generator includes:a housing having an upper end and a lower end and defining a cavity having a vertical axis, the housing including a liquid inlet in the lower end of the housing and a vapor outlet in the upper end of the housing; anda generator core received within the cavity, the generator core including a plurality of spacers and a plurality of electrodes, each of the plurality of spacers formed of a dielectric material and positioned between two adjacent electrodes of the plurality of electrodes to define a plurality of vertically spaced fluid chambers including a lowermost fluid chamber and an uppermost fluid chamber, each of the plurality of electrodes defining a plurality of openings to facilitate fluid flow from the lowermost fluid chamber to the uppermost fluid chamber.

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