Water Vaporizers

Abstract

An air humidifier is provided with an enclosed evaporator wherein electrodes extend into water within the evaporator and electrical conduction between the electrodes occurs through the water. The heat so generated converts the water to steam and the evaporator has a steam chamber connected, by a nozzle equipped steam line, to the air which is to be humidified. The water sump of the evaporator is connected to a water supply by means of a feed line through which a constant quantity of water is supplied in an amount exceeding the amount of water evaporated. The sump is also connected to an overflow discharge line. A discharge orifice, communicating with the feed line and the overflow discharge line, is arranged in the bottom of the evaporator and the overflow is vertically adjustable to control the water level in the evaporator.

Description

BACKGROUND OF INVENTION

This invention relates to humidifiers and, more specifically, to the evaporator portion of a humidifier.

Generally, humidifiers incorporating evaporators of the type described above are well known, that is evaporators wherein water is converted into steam by electrical conduction through the water between electrodes extending into the water. For example, such evaporators are described in Swiss Pat. No. 389,208 and U.S. Pat. No 3,219,796.

SUMMARY OF INVENTION

Among the objects of this invention are to provide for control of the power input to the evaporator and thereby control steam generation, and also to hold the electrical conductivity of the water relatively constant.

For the achievement of these and other objects, this invention proposes an arrangement wherein the water level within the evaporator is responsive to the position of an overflow discharge line which communicates with the evaporator sump. The overflow discharge line is adjustable vertically to control the sump water level and in so doing controls the area of the electrodes immersed in the water and correspondingly the power input to the evaporator. Furthermore, a discharge orifice through which water circulates from the evaporator is located in the bottom of the evaporator. Salt concentrations and dirt collecting in the bottom of the evaporator are conducted away through the discharge orifice to thereby maintain the electrical conductivity of the water relatively constant.

DESCRIPTION OF DRAWINGS

FIG. 1 shows a vertical section through an embodiment of this invention;

FIG. 2 shows a vertical section through an alternative embodiment; and

FIG. 3 represents a section generally along line III-III of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENT

In the embodiment of FIG. 1, an enclosed evaporator vessel 1 of a humidifier is illustrated in connection with a part of the humidifier water supply and an overflow discharge line. The remainder of the humidifier has not been illustrated as it is not essential to an understanding of this invention but reference may be had to the aforementioned U.S. patent should a more complete description thereof become necessary. The evaporator vessel contains two generally cylindrical, concentrically arranged electrodes 2 and 3, which may be made of metal wire mesh for example. Leads 4 and 5 are conductively connected to an electrical source. The cover of the vessel 1 carries steam line 6, which includes a replaceable or adjustable nozzle 7 through which steam is directed into the air being humidified. Opening 6a forms the inlet to steam line 6 from the interior of the vessel. Water feed line 8 opens into vessel 1 through inlet 8a located at the bottom of vessel 1. In a conventional manner line 8 (not shown) may be provided with a filter (not shown), if desired, a pressure-reducing valve (not shown) and an input valve 10. The entire line 8 and all its components are constructed and adapted in such a way that the input of water to evaporator vessel 1 per unit time is greater than the amount of water which can be evaporated in the vessel during that same time interval. An overflow discharge line communicates with the evaporator vessel through an opening in the bottom of the vessel. Vertical section 9 of the overflow line opens into the bottom of vessel 1 and is closed at its free lower end by an outlet valve 11 which allows selective discharge of the contents of evaporator vessel 1 into funnel 12 and a drain line attached to the funnel. A further section 13 of the overflow discharge line extends from section 9 and an overflow discharge part 14 slides over the free upper end of section 13. The overflow discharge part 14 has a watertight connection with section 13 but is vertically adjustable on that section. Overflow part 14 consists of overflow 14a having an overflow orifice 14b positioned above funnel 15, and vent 14c.

As the water feed line 8 is opened, water will rise in vessel 1 to the level of overflow 14a and, thereafter, run off through the overflow orifice 14b. As electric voltage is applied across the electrodes 2 and 3 the water is heated between them and converted to steam. The generated steam rises into the upper part of vessel 1 which provides a steam chamber. Instant escape of the steam through line 6 is restricted by nozzle 7 and a back pressure is built up in the steam chamber by the accumulation of steam to thereby depress water level 16. In this way the amount of electrode surface immersed in water is reduced and the electrodes no longer contribute with all their surface to the generation of steam. This will thus reduce the amount of steam being generated. It will be seen that by raising or lowering the overflow 14a one can raise or lower the water level 16 in the evaporator vessel 1 and, thereby, increase or decrease the generation of steam.

Due to the fact that electrodes 2 and 3 do not extend to the bottom of vessel 1, the water in the area of the vessel bottom remains essentially unheated. As a result, the overflowing water passing through vertical section 9 of the overflow line (which results from supplying water to vessel 1 in excess of that which the electrodes can evaporate) carries out dirt particles, salt concentrations, and other deposits which collect at the bottom of the vessel, but does not carry off a significant amount of heat energy.

In alternate embodiment shown in FIGS. 2 and 3, the evaporator vessel has a wall 21. The two electrodes 29 and 30 are attached to the lid 19 of the evaporator vessel and are planar in shape, although, other electrode forms could be used. Steam line 32 communicates with the interior of the evaporator vessel and carries a nozzle 33 similar in construction and operation to nozzle 7. Water feed line 22 opens into the vessel through inlet port 22a in the vessel bottom 20. Slightly above bottom 20 a distributor plate 23, having a plurality of spaced openings 23a therein, serves to distribute the incoming fresh water uniformly over the entire cross section of the vessel. Above the distributor plate 23 the wall 21 of the vessel has two or more openings 24 through which the incoming water may enter a second vessel defined by walls 21 and 25. Both walls 21 and 25 create a hollow-cylindrical or annular space 35 therebetween into which an overflow tube 26 is inserted from the bottom. Tube 26 has a watertight connection at the vessel bottom but is vertically adjustable. Hollow cylindrical space 35 has a vent opening 27 in lid 19 and, if desired, a connecting line 28 can be provided to return condensate from the nozzle exit.

As can be seen from the drawing, there is also a hollow cylinder 31 fastened to the lid 19 and protruding into the evaporator vessel down approximately to the level of the openings 24 to the overflow line created by the annular space 35 and the tube 26. The hollow cylinder may be an integral part of the lid 19.

As water flows into the empty vessel from the fresh water line 22, it rises inside cylinder 31 and rises as well in space 35 up to the upper rim of the overflow tube 26. The space between walls 31 and 21 is generally closed except at its bottom end and air in the space will be compressed slightly while the space stays essentially waterfree. This air space provides good thermal insulation between the water inside the evaporator vessel and the water in space 35.

Steam is generated when the electrodes are connected to an electrical source and that steam is delivered through the steam line 32 to the air which is to be humidified. The nozzle 33 within steam line 32, however, retards the flow of steam and causes a slight overpressure within the steam generator (above water level 34 in the evaporator) which lowers water level 34 and, thereby, reduces the effective area of electrodes 29 and 30. By adjusting the vertical position of overflow tube 26, the operating level 34 of the water can be varied and thereby control the output of the device. It should be noted that, here too, the water overflow (due to delivering water in excess of that which can be evaporated) maintains the electrical conductivity of the water inside the evaporator relatively constant, because the constant through-flow at the bottom of the vessel carries off whatever particles or impurities which might tend to collect there.

Claims

I claim:

1. A water evaporator comprising, in combination, an evaporator vessel,

spaced electrodes each having a length exposed in the interior of said vessel,

water supply means opening into said evaporator vessel in the lowermost portion of said evaporator vessel for admitting water into said vessel to immerse said electrodes so that the electrical circuit between said electrodes is made through water in said vessel,

current in said water heating said water to convert said water to steam and said water supply means further operative to provide water in excess of the evaporation capability of said evaporator,

means communicating with the interior of said vessel above the level of said water for conveying steam to air to be humidified,

means defining a water overflow line communicating, through a water discharge from said evaporator vessel located in the lowermost portion of said evaporator vessel and through which excess water supplied to said evaporator vessel is discharged, with the interior of said vessel and having a vertically adjustable overflow point so that the level of water in said vessel, and accordingly the amount of electrode immersion in water, can be controlled by varying the vertical position of said overflow point,

a distribution plate arranged above the level of the opening of said water supply means into said evaporator vessel extending between the walls of said evaporator vessel and having means defining a plurality of apertures therein so that said distributor plate distributes water uniformly over the cross section of said evaporator vessel,

said water discharge comprising at least one opening above the level of said distribution plate in the lowermost area of said evaporator vessel and said water discharge opening communicating with said water overflow,

a top on said evaporator vessel,

and a hollow generally cylindrical wall extending from said top into said evaporator vessel and terminating at the level of said water discharge opening, said cylindrical wall spaced from said evaporator vessel and defining therewith a generally closed space open only at the bottom.

2. The water evaporator of claim 1 including an outer wall surrounding said evaporator vessel and defining therewith an overflow space communicating with the interior of said evaporator vessel through said discharge opening and providing a part of said water overflow,

and wherein said overflow includes a generally cylindrical member extending through the bottom of the space between said outer wall and evaporator vessel wall into said overflow space with the upper end of said cylindrical member providing the overflow point for said overflow.

3. The water evaporator of claim 2 including means defining a nozzle in said means for conveying steam from said evaporator vessel and operative to retard the flow of steam from said evaporator vessel and thereby produce a back pressure on the water in said evaporator vessel.