Abstract:
A personal steamer comprising an assembly of three pieces: a base tub and liner tub and a lid. The liner tub is body-shaped to form a foot, a seat, a back and side walls forming a steam enclosure. A lid, hinged at the foot, can be pivoted to a vertical, low stress vertical position, or closed for use. The liner tub is formed of ABS and reinforced with fiberglass on its underside where it is protected from the steam. The liner tub is fitted into the base tub and foamed together, forming a base assembly. Steam is conducted through a fitting in the base tub and through a conduit to a horn outlet at the user&#39;s feet. The steam is discharged away from the user and towards the lid, deflecting back to into the enclosure. U-shaped conduits and fans recirculate steam in the enclosure. A portable steam generator is coupled with the cabinet for providing constant temperature steam very quickly. A low volume boiler, having a V-shaped bottom and a gravity water feed ensures minimum water levels and minimum water volumes. A vacuum-lock water reservoir provides water supply and fine level control.

Description:
FIELD OF THE INVENTION 
     The current invention relates to personal steam cabinets or saunas and their method of manufacture, more particularly to the arrangement and multi-piece manufacture of the base and the means for recirculation or steam within the cabinet. 
     BACKGROUND OF THE INVENTION 
     A number of devices are known to provide a steam bath or sauna in a compact and personal form. Simply, a steam enclosure is provided in which a user resides. There is provided means for entry and means for generation of steam. One additional advantage of a personal steam cabinet is that the user&#39;s head projects outside of the top of the cabinet and enables breathing of fresh cool air. 
     Despite the appeal and therapeutic benefits of personal steam cabinets, the present designs have various shortcomings. Some of these shortcomings include the broad areas of: maintaining cabinet integrity under in the warm temperature regime; both structural and the environment; heat control; uniformity of heat application and user comfort support; and the need for replenishment of the water supply. 
     Regarding the structure, other rigid enclosure clamshell designs utilize side hinge placement. When open, the weight of the lid bearing of the hinge can damage the lid and cause the hinge structure to failure prematurely. Under the prolonged application of steam heat and if subsequently left in the open position, the lid relaxes and deforms under gravity into a more oblong shape. Further, or alternatively, the hinges pull free from the lid or base due to the mechanical advantage. Either of the shape change, or movement in the hinges result in an improperly fitting lip and base portion. When the cabinet changes its shape or the door shifts, the seal is jeopardized, causing steam and condensation to escape. The same problems occur to a lesser extent with models having a split lid and, while sagging is less of an issue, the extra peripheral area requires additional seals and steam and moisture leakage increases proportionately. 
     Further, the usual materials and method of manufacture utilize fiberglass resins or otherwise urea-based construction. Exposing these types of materials to prolonged steam exposure and temperature ultimately cause styrene or urea to be released, both of which are unpleasant; both due to its odor and when it comes in contact with the now open pores of the user. 
     Regarding the steam experience for the user, it is common to have a great disparity in temperature between the upper and lower regions of the cabinet. Additionally, when the steam condenses it tend to pool unpleasantly about the user&#39;s feet. 
     The supply of steam has been associated with various disadvantages including the need is some cases for plumbed supply, or in the case of portable units, small reservoirs and the need for constant refilling. In the fill-and-evaporate systems, as the steam boilers empties, the danger of scalding heightens as the steam becomes hotter. 
     The applicant&#39;s cabinet and steam supply avoid the above mentioned problems and provide a convenient and environmentally sound and pleasant steam cabinet. 
     SUMMARY OF THE INVENTION 
     In a preferred form of the invention, a personal steam cabinet, formed of non-volatile ABS plastic, is manufactured as an assemblage of three-pieces: a base tub, a liner tub and a lid. The liner tub is fitted with various operational and structural features and then is installed into the base tub. The lid is hinged at the foot of the base tub. The liner tub supports a partially reclining user, and when the lid is closed, the liner tub forms a steam enclosure about the user. The flexible ABS liner tub is reinforced with fiberglass, the reinforcing being located on the liner tub&#39;s underside so as to isolate it from the steam. Hot spots are avoided through fan-equipped, U-shaped recirculation conduits with inlet and outlets being located in the liner tub for access to the steam enclosure. A horn structure at the foot of the liner tub is connected via steam conduit to a steam inlet on the base tub. The horn is fitted with a plurality of steam outlets which are directed towards the lid so as to avoid direct contact of hot steam and the user and to use the lid to deflect the steam back into the enclosure. 
     In a preferred combination, the above steam cabinet is combined with a portable steam generator, connected by a steam conduit and a control line. The control line provides low voltage power to the onboard fans and for transmitting a temperature signal from a temperature probe in the cabinet. 
     Preferably, the portable steam generator is a gravity water feed system which slowly provides water under vacuum level control from a water reservoir to a boiler, the level control ensuring only a minimum volume of water which barely covers the electric heater. The minimum water volume heats very quickly and the level control ensures constant temperature of the generated steam. 
     Accordingly, in one broad aspect, a personal steam cabinet is provided comprising a base tub forming a cavity and having a first periphery, a liner tub forming a steam enclosure and having a generally W-shaped, body-contoured inside lounge portion, the lounge portion being fitted with one or more U-shaped steam conduits each having a outlet and an inlet communicating with the enclosure, the liner tub being insertable into the cavity in the base tub and having a second periphery which mates and seals to the first periphery when so inserted so as to form a base assembly having foot and a head; a fan or fans for inducing flow through each U-shaped steam conduit to recirculate steam in the enclosure; a steam supply conduit extending from the base tub to the lounge portion for conducting and discharging steam into the enclosure; and a closable lid having a third periphery which mates with the second periphery when the lid is closed and substantially sealing the enclosure, the lid having a foot and a head adjacent the foot and head of the base assembly respectively, the lid&#39;s head having a cutout for permitting passage of a user&#39;s head. 
     In another broad aspect of the invention, a method of manufacturing the personal steamer comprises the steps of: providing a base tub; providing a liner tub forming a steam enclosure having a body-supporting lounge topside and an underside; installing one or more steam enclosure recirculation conduits to the underside of the liner tub; installing a steam supply conduit between the liner tub and the base tub; fitting the liner tub into the base tub and sealing them together to form a base assembly having a foot, a head and an enclosure periphery; and installing a lid having a foot, a head and a periphery, the lid being hinged at the foot of the base assembly for operation between two positions, the lid periphery sealing to the base assembly&#39;s periphery in a first closed position and the lid permitting access to and from the steam enclosure in the second open position. 
     More preferably, the personal steamer further comprises a portable steam generator connected to the steam supply conduit, the generator having a boiler with a heater immersed in a shallow, level-controlled water supply, the level of the water supply being controlled using a gravity fed, vacuum-locked water reservoir and a fan for directing the steam to the steam supply conduit. 
     In a more particular aspect of the invention, the portable steam generator comprises a dish into which a neck of a water reservoir is immersed so as to form a vacuum-lock and gravity feed of water from the reservoir; a boiler having a bottom, side walls, a freeboard volume and an electrical immersion heater, the heater positioned adjacent the bottom and the side walls constricting the volume about the heater; a conduit between the dish and the boiler, the elevation of the dish being such that the minimum volume of water is maintained in the boiler to immerse the heater; and a fan for directing air through the freeboard of the boiler to conduct steam to a steam supply conduit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the assembled personal steamer with the lid in the fully opened position; 
     FIG. 2 is a perspective view of the assembled personal steamer of FIG. 1 with the lid in the closed position; 
     FIGS. 3 a  and  3   b  are both left side views of the personal steamer of FIG. 1, with the lid in the opened and closed positions respectively; 
     FIG. 4 is an exploded view of a three-piece embodiment of the personal steamer illustrating the lid, the liner tub and the base tub; 
     FIGS. 5 a  and  5   b  are side and plan views respectively, of the lid of FIG. 4 with the drip lip illustrated as though the lid were transparent; 
     FIG. 6 is a side view of the liner tub with the lounge portion visible through the side walls; 
     FIG. 7 is a side cross-sectional view of the base tub showing the liner tub installed therein and the lounge portion visible therethrough; 
     FIG. 8 a  is a top view of the personal steamer in combination with a portable steam generator; 
     FIG. 8 b  is a partial perspective view of a user&#39;s feet resting at the foot of the base assembly and with steam issuing from the horn; 
     FIG. 9 is a partial cross-sectional view of the boiler and gravity feed water supply of the portable steam generator; and 
     FIG. 10 is a schematic of the boiler water system and the electrical and control system for the portable steam generator. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Steam Cabinet 
     Having reference to FIGS. 1 and 8 a,  the present invention comprises a personal steam cabinet  10 , its method of manufacture and a portable steam generator  11  for use therewith. 
     The cabinet  10  comprises three parts: a base tub  12 , a liner tub  13 , and a lid  14 . The concave liner tub  13  forms a steam enclosure  15 . The topside of the liner tub comprises a generally W-shaped lounger portion  16 , which is body-contour formed and slightly reclining to comfortably support a person or user sitting therein. Accordingly, the lounger has a foot  17 , a seat  18 , a back  19  and side walls  20 . 
     Referring to FIGS. 3 a  and  3   b,  the concave base tub  12  has a substantially rectangular footprint and forms a cavity into which auxiliary equipment is fitted and into which the liner tub  13  is installed for forming a base assembly  21 . The lid  14  has a foot  22  and a head  29  and is pivotally connected or hinged at its foot to the base assembly. A cutout  38  is provided at the head  29  of the lid for passing the user&#39;s neck and head. 
     The assembled base assembly has a lip or periphery  23  rising diagonally from a foot to a head. 
     The cabinet  10  is provided with a steam inlet  30  and an electrical supply  31 . Referring to FIG. 4, the cabinet&#39;s multi-piece construction permits the installation of various steam-sensitive enhancements within the protected portions, yet still maintain and low maintenance surfaces. 
     The lid  14  is designed with a foot hinge system and thus offset weight bearing and its associated structural problems are eliminated. The hinge  24  (not detailed) is secured to the foot  17  of the base assembly  21  and to the foot  22  of the lid  14 . The lid  14  has a periphery  23   b  and is formed with an overlapping lip  25 , which forces the lid to self-center in relation to the periphery  23  of the base assembly. Gravity helps the lid&#39;s periphery  23   b  seal on the entire periphery  23 . 
     The lid  14  is formed of ABS (acrylonitrile butadiene styrene) and thereby avoids the urea emission problems. A V-shaped groove  26  is formed in the lid  14  to provide additional structural integrity to the otherwise unreinforced lid. The lid  14  remains as unreinforced ABS so that it is easily cleaned. 
     Turning to FIGS. 5 a  and  5   b,  an internal drip lip  27  is attached to the inside of the lid  14  and offset inwards from most of its periphery  23   b.  The drip lip  27  forces condensation to be directed internally to the base assembly&#39;s periphery  23  and to collect in the bottom or foot  17  of the cabinet  10  allowing for easy clean up rather than drip outside on the floor or carpet. The drip lip  27  also minimizes opportunity for direct steam escape as it serves to direct most of the steam past the seal and back into the environment. Small hydraulic rams  28  control opening and closing of the lid  14 , restricting the maximal range of opening to a vertical position and also to prevent lid-slamming incidents. 
     The base assembly  21  further solves several of the problems associated with the prior art cabinets. 
     Referring to FIGS. 6 and 7, the liner tub  13  is also formed primarily of ABS and thereby avoids the urea emission problems. However, in achieving a balance between strength and weight, the typically 6 mm inch thick ABS itself is generally not strong enough to rigidly support a person under operating conditions. Accordingly, the lounger portion  13  of the liner tub  13  requires reinforcement  33 , such reinforcement being applied to the underside of the ABS lounger portion  16 . A suitable reinforcing material can be fiberglass, as its position on the underside of the ABS is protected from the hot steam environment. The reinforcement  33  is applied to the underside of the lounger portion to: the small of the back area  19 , the seat area  18  and under the raised foot portion  17 . Typically, about 6 mm of fiberglass is added as reinforcement. 
     The inside of the ABS base tub  12  is similarly reinforced with fiberglass, providing a strong structure and yet a durable ABS finish on the outside (not detailed.) 
     The topside of the lounger portion  16  is an ergonomically designed seat allowing for the most relaxed sitting position. While prior art cabinets have the user sitting bolt upright on bench-style chair, the lounger portion  18  seat area is designed to allow maximum relation for stress relief. If the user falls asleep, his or her head lies gently against the back  19  of the lounger portion rather than snapping forward. Armrests  34  are formed into the side walls  20  so that user with back or hip problems can support and align themselves. 
     A raised foot grid  35  of ribs at the foot  17  of the lounger portion  16  lifts the user&#39;s feet off of base assembly  21  where condensation collects and allows a warm circulating environment under the feet (See FIG. 8 b ). 
     Once the reinforcement to the lounger portion  16  and base tub  12  are applied, the liner tub  13  could be inserted into the base tub  12 , however, there are additional enhancements associated with the liner tub  13  before it is so assembled. 
     In the prior art cabinets, generated steam rises from a pan boiler or is blown out a nozzle with no care for uniformity in cabinet temperature. As the steam heat rises it is common in prior art cabinets for head and chest temperature to be up to 20 degrees F. hotter than the foot temperature. 
     To ensure proper circulation of the steam provides uniform temperature throughout the cabinet, recirculation fans are provided. One or more U-conduits  40  are installed to the lounger portion  16  for drawing in steam environment from the steam enclosure  15  at one location  40   a  along the lounger portion  16  and ejecting it at another location  40   b.  To provide steam movement in the cabinet  10  is usually sufficient, however, an up to down recirculation is preferred. Two low voltage fans  41  are placed in-line in the U-conduits  40  for circulating steam and evening-out the temperature in the steam enclosure  15 . Through active recirculation of the steam, the user is able to withstand more intense steam, will not get cold feet and the potential for hotspots is reduced. 
     Referring to FIGS.  6 , 7 , 8   a  and  8   b,  hot steam is conducted from the steam inlet  30  located anywhere in the base tub  12  and is directed through a steam connection or external steam conduit  42   b  to the foot  17  of the base tub  12 . An internal steam conduit  42   a  within the base tub conducts steam to a steam conducting hollow structure or horn  44 . The horn  44  projects upwardly and is located between the user&#39;s feet. The horn  44  is fitted with a plurality of steam outlets  45  for directing the steam forwards, away from the user&#39;s feet and towards the foot  22  of the lid  14 . The steam is deflected back from the lid  14  into the enclosure  15  and can move laterally and upwardly from the lid and thus be diluted in the steam environment, lessening any hot spots before contacting the user. 
     A temperature probe  46  is provided further in the enclosure, which is tied into a safety interlock with the steam supply. Once each of the steam conduit  42  to the horn  44 , the U-conduit  40  and fans  41 , and the temperature probe  46  are installed into the liner  13  and base tubs  12  they are assembled together to form the base assembly  21 . 
     The liner tub  13  has a peripheral edge  23   a  that is matched to the peripheral edge  23   c  of the base tub  12 . The liner tub&#39;s  13  peripheral edge  23   a  overlaps the base tub&#39;s peripheral edge  23   c.  Once assembled the liner  13  and base tubs  12  are foamed together with foamed-in-place insulation through a suitable access port formed through the base tub. The foam insulates, covers and fixes the steam conduit  42  and fan  41 , temperature probe  46  and control wiring in place. A bead of sealant, such as silicone, is run about the interface of the two peripheral edges  23   a,    23   c.    
     Once assembled, a stainless steel hinge  24  is riveted to the lid  14  and to the foot  17  of the base assembly  21 . 
     Steam Generator 
     A common problem with all portable steam generating systems is that in order to achieve a desirable 30-minute steam experience, it generally takes 7-12 minutes for pre-heating. This preheat time is a function of the large water volume that must be raised from room temperature to steam-generating temperature through the use of electrical heating elements. In addition to the perceived deterrent to use because of the extra inconvenience the preheat causes, this delay also causes significant downtime when used in a commercial application. Faster heat time of this large volume of water is not achievable within the constraints put on heater size by a standard 110V, 15A electrical circuit. 
     Accordingly, and having reference to FIGS. 8 a,    9  and  10 , a new portable steam generator  11  is provided utilizing a new boiler  50  which reduces pre-heat time to approximately 3 minutes in two ways. First, the design of the V-shaped boiler  50  design minimizes the amount of water required to submerge heating element  51  positioned in the narrow bottom or apex  52 . A minimum level  53  of water is maintained in the boiler  50  which just covers the heating element  51 . Accordingly, the volume of water required to cover the element  51  is significantly reduced over the prior art boilers holding an entire water supply. A further 22% reduction in volume is achieved using the V-shape compared to a rectangular design prior art boiler. 
     Secondly, a water reservoir  55  operates as part of a vacuum trickle drip system which feeds water slowly to the heater  50  only as it evaporates. This means that the maximum water level is also close to the minimum water level  53  throughout the steam cycle. Prior art portable, non-plumbed steamers utilize a one-time fill, which has the water level starting out much higher than at the end of the reservoir capacity. 
     The trickle drip system allows a user to fill or provide a commercial bottled water feed reservoir  55  suitable for multiple steam applications, allows the user to visibly see when refill is required, makes the refill process easy, and keeps the water level as an optimal minimum level  53  at all times. 
     Further, by keeping the water level at the minimum level  53  it helps minimize preheat time. Additionally, the trickle system keeps the water level in the boiler constant, which in turn keeps the steam temperature constant. 
     As shown in FIG. 8 a,  the cabinet  10  is connected to the portable steam generator  11 . A steam conduit  42   b  extends from the steam generator  11  to the cabinet&#39;s steam inlet  30 . Further, a low-voltage control line  39  extending from the steam generator  11  and cabinet  10  conducts power to the recirculation fan  40 , or fans, and the signal back from the temperature probe  46  to the steam generator  11 . The water bottle reservoir  55  is shown in place over the steam generator  11 . 
     Referring again to FIG. 9, the trickle system comprises the V-shaped boiler  50 , the water reservoir  55  and a dish  56  forming a water pool  57 . The boiler&#39;s V-shaped apex  52 , or constricted volume of the boiler  50 , minimizes the volume and mass of water which must be heated to form steam. The electric immersion heater  51  is positioned low the apex  52 . 
     The water reservoir  55  has a neck portion  58  is shown projecting into the pool  57 . Water is gravity fed from the water reservoir  55  into the pool  57 . Water replenishes the pool  57  as soon as the water level  53  drops sufficiently to break the vacuum in the reservoir  55  and allow air back in. In this way the level  53  in the pool  57  is closely controlled, regardless of the water level  59  in the reservoir  55 . 
     The water pool  57  is conducted through a conduit  60  to the boiler  50 . The water level in the pool  57  is maintained at the minimum water level  53  in the boiler  50 . 
     Turning to FIG. 10, a 110 v, 15A line  70  is fed to power distribution and control module (DSTA)  71 . An over temperature power cutout  72  (190-200° F.) interrupts the power to the DSTA  71  in over-temp situations. The DSTA  71  monitors the temperature probe  46  from the cabinets, accepts programming control (such as time and temperature set points) from a control panel  73  and outputs various characteristics, including temperature to a control panel display. The DSTA  71  controls the boiler&#39;s heater  51  powered by a 5500 W electric element. 
     The boiler  50  further comprises a boiler fan  74 , which draws fresh air through an air intake conduit  75 , and forces generated steam in the freeboard area  78  through at outlet conduit  76  and steam connection  42   b  to the cabinet  10 . A 110V AC to 4.5V DC (or 12V—depending on the fans) power supply  77  is provided which operates the boiler fan  74  and also powers the steam recirculation fans  40  through the cabinet control line  39 .