United States Patent Dines HUMIDIFIER [72] Inventor: David R. Dlnes, 4801 N. W. 34, Oklahoma City, Okla. 73122 22 Filed: April 15, 1971 21 Appl.No.: 134,249

[52] U.S.CI ..219/27l, 126/113, 261/142 [51] Int. Cl ..F22b 1/28 [58] Field of Search ..2l9/271-276, 284,

[56] References Cited UNITED STATES PATENTS 1,580,293 4/1926 Fitzer ..2l9/273 June 13, 1972 3,219,796 11/1965 Grafet a1 ..2l9/285 Primary Examiner-C. L. Albritton Attorney-Robert K. Rhea [5 7] ABSTRACT Aboiler formed by a water containing vertically disposed casing having a heater in its depending end portion is provided with a steam outlet at its upper end portion. An overflow tube, connected with the depending end portion of the case, drains minerals and salts tending to accumulate in the bottom of the casing. A thermal switch secured to the depending end of the case operates a water flow controlling solenoid valve which refills the casing in response to temperature changes of the casing in converting water contained thereby to steam.

5 Claims, 4 Drawing Figures PATENTEDJUH 13 m2 FIG.I

I lll I DI NES /NVENTOR.

DAVI D HUMIDIFIER 1. Field of the Invention The present invention relates to humidifiers and more particularly to an improved humidifier which may be used as an individual unit or in combination with a forced draft heating unit.

It is generally well understood that for comfort it is necessary to maintain an adequate level of humidity within the air within buildings being heated. Further, it is recognized that a proper level of humidity permits room temperature to be kept slightly lower with no uncomfortable affects, thus, lowering fuel costs and further preventing furniture and other household items from drying out.

2. Description of the Prior Art A plurality of humidifiers are disclosed by prior patents which generally are used in combination with a forced draft furnace controlled by a humidistat, such as US. Pat. Nos. 2,347,490; 3,294,081; 3,305,173 and 3,443,559.

Some of these prior art humidifiers employ the heated air from the furnace for evaporating water contained by porous elements in the path of hot air flow while others utilize a fine spray or mist or water in the air stream. This type of humidifier is generally bulky and usually gets out of order, such as by minerals and salts, deposited by the water,'clogging the orifices forming the water spray in the air supply and collecting on the air ducts interior wall surfaces. Humidifiers which employ a separate heating element for evaporating water frequently become inoperative as a result of minerals and salts from the water forming a scale which restricts the water and steam openings.

This invention is distinctive over the above named patents by providing a humidifier which may be operated as an individual unit or in combination with forced draft furnaces. This device includes means for removing scale formed by minerals and salts in the water when the latter begins to accu mulate. Further, this invention is distinctive over the humidifiers disclosed by the prior art by its simplicity and construction of relatively few components, thus reducing its initial cost, which includes a temperature responsive switch actuated by a water evaporating boiler and requiring only a source of water and a source of electrical energy to place it in operation.

SUMMARY OF THE INVENTION A boiler is formed by an elongated vertically disposed casing having a heating element containing tube member sealed with and extending upwardly in the depending end portion of the casing. The upper end of the casing is provided with a normally open steam vent. Adjacent its upper end portion the casing is connected with a water supply pipe having a solenoid controlled valve interposed in the water supply pipe. An overflow tube is connected with the depending end wall portion of the casing for flushing the casing into a drain each time the casing is refilled. A temperature responsive switch, connected with the casing wall at its depending end portion, opens the solenoid controlled valve for' admitting water to the casing in response to a temperature rise, above a predetermined setting, each time the heating unit evaporates the water, contained by the casing. Water entering the casing reduces the casing temperature below the predetermined setting of the temperature responsive switch thus closing the solenoid operated valve.

The principal objects of the invention are to provide a humidifier which utilizes a boiler to vaporize water which is automatically refilled by a temperature responsive switch each time the water in the boiler is evaporated and which flushes the boiler free of scale accumulated in the boiler each time it is refilled.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2 is a horizontal cross-sectional view, to a larger scale,

,taken substantially along the line 2-2 of FIG. 1; and,

.provided with a float-type ball valve and cage means FIGS. 3 and 4 are wiring diagrams illustrating different embodiments of the device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Like characters of reference designate like parts in those figures of the drawings in which they occur.

In the drawings:

The reference numeral 10 indicates the device, as a whole, comprising a boiler 12 connected with a water supply pipe 14, overflow tube means 16 and a controlling thermal switch 18. The boiler 12 comprises an elongated vertically disposed casing 20, preferably formed from a selected length and diameter of copper tubing, having an elongated downwardly open tu bular member or heater housing 22, of similar material and diametrically slightly smaller than the inside diameter of the casing, vertically disposed in the depending end portion thereof. The depending ends of the casing 20 and housing 22 terminate in a common horizontal plane and are joined in fluid tight sealing relation by a centrally bored seal 24 having an annular flange 26 interposed between the innerwall surface of the casing and the outer wall surface of the tubular housing 22 thus maintaining the housing coaxial with respect to the longitudinal axis of the casing 20. The housing 22 coaxially receives, in close spaced relation, an elongated electrical resistance heating element 28 which is maintained within the housing 22 by a centrally bored plug member 30 extending through the bore of the seal 24 and frictionally received by the depending inner wall surface of the housing 22.

The upper end portion of the casing is provided with a diametrically reduced tubular vent 32 for exhausting steam to the ambient air in the manner hereinafter explained. A cage 34, having a seat 36 opened and closed by a float-type ball valve 38, is coaxially disposed within the casing and connected to the upper end wall 40 of the casing in communication with the bore of the casing vent 32. v

The drain tube means 16 comprises a first tube 42 diametrically smaller than the casing 20, which is coaxially connected horizontally, at one end, with the casing wall in close spaced relation with respect to the upper limit of the sealing flange 26. Intermediate its ends and adjacent the casing the tube 42 is deformed to describe a substantially U-shape, indicated at 44, defining vertical parallel leg portions 46 and 48 with the leg portion 48 projecting upwardly substantially coextensive with the upper limit of the casing 20. A second drain tube 50 is horizontally connected, at one end, with the first tube leg 48 at a selected position intermediate its ends, preferably spaced above the upper limit of the heater housing 22, with the other end portionof the second tube 50 turned downwardly and opening into a drain, or the like, indicated at 52, disposed below the lower limit of the first drain tube U-shaped portion 44. The upper end portion of the first tube leg 48 is similarly 54 which is normally open for admitting air to the tubes 42 and 50 to prevent a syphoning action and draining water contained by the casing 20.

The water supply pipe 14 is connected with the wall of the casing 20 adjacent its upper end portion in upwardly spaced relation with respect to the horizontal plane defined by the connection of the second tube 50 with the first tube leg 48. An open-closedwater control valve 56 is interposed in the water supply line 14 and a solenoid controlled valve 58, including a solenoid coil 59, is interposed in the water line 14 between the valve 56 and casing 20.

The thermal switch 18 is a conventional temperature responsive switch operated by differential expansion of a surrounding metallic case operating a low expansion metal bridge, contained by the case, which opens and closes a pair of contacts in the case manually adjusted by the external end of an adjusting screw 60. The contacts of the thermal switch 18 open on temperature rise. This thermal switch 18 is commercially available from Fenwal, Inc. of Ashland, Mass. and is marketed under the trade name TI-IERMOSWITCl-I, series No. 30000, relating to nonindicating surface mounting temduction means comprising a slug 62, generally rectangular in transverse section, formed of heat conducting metallic material, such as copper, having a predetermined thickness, is interposed between'the mounting surface of the thermal switch 18 and the outer surface of the casing wall for increasing the thermal inertia of the switch 18 by forming a time delay in the conduction of heat transmitted to the thermal switch 18 from the boiler 12. g

A spacer 27, which may be an extension of the flange 26, is disposed between the walls of the housing 22 and casing 16 substantially coextensive with the thermal switch case for more efficient heat conduction.

Referring more particularly to FIG. 3, a source of electrical energy AC. has one source wire 64 connected with the heater 28 with the other wire 66 of the heater connected to one terminal 68 of the thermal switch. The other current source wire 70 is connected to the other terminal 72 of the thermal switch through an oiT-on switch 71. The contacts 68 and 72 of the thermal switch 18 are bridged by an arm 73 in FIGS. 3 and 4 for illustrative purposes since in actual practice they make and break with each other. Other wires 74 and 76, connected, respectively, with the thermal switch terminal 72 and wire 66 are connected at their respective'other ends to the terminals of the solenoid coil 59.

' OPERATION In operation the device is assembled and connected with the water supply pipe 14 and current source A.C. as described hereinabove'. The device is placed in operation by manually opening the water control valve 56 and closing the off-on current supply switch 71. This places the resistant heater 28 in operation without water being present in the casing 20. As soon as a predetermined temperature is reached, determined by the setting of the thermal switch 18, the thermal switch opens its normally closed contacts, by moving the arm 73, so

that current is applied to the solenoid 59 over the wires 74 and 76 thus opening the solenoid valve 58 and admitting water, in-

dicated by the lines 78, to the casing. The water fills the casing to the level of the connection of the second tube 50 with the first tube leg 48 wherein any excess water entering the casing 20 drains through the second tube 50. Water entering the casing 20 reduces the temperature of the casing and this reduction of temperature is sensed by the thermal switch 18 through the slug 62 which closes the thermal switch arm 73 with the contact 68 defenergizing the solenoid coil 59 and interrupting the water supply to the casing 20 wherein the resistance heater 28 heatsv the water 78 and vaporizes it. Steam, not shown, is generated and exhausted through the casing vent 32. In the event of malfunction of the thermal switch 18 causing the solenoid valve 58 to remain open water entering the casing is continuously drained ofi through the drain tubesgl6. In the event impurities in the water restrict the overflow of water through the drain tubes the ball valves in the top of the casing and at the top of the first tube leg 48 are lifted by the water and seal with their respective seats to prevent water being discharged into the area around the device through the vent or upwardly open end of thefirst tube leg 48. The close spacing A supply means includes:

between the outer wallof the heater housing 22 and inner wall surface of the casing 20 limits the volume of water contained therebetween and relatively quickly evaporates the water 78. As this occurs the heater temperature again rises and opens the contacts of the thermal switch to refill the casing 20.

Referring also to FIG. 4, the current source wires and 64 may be connected with the terminals of a forced draft furnace motor 80, or the like, so that this humidifier may be operated only when the forced draft furnace is in operation and supplyin heated air to the building.

bviously the invention IS susceptible to changes or alterations without defeating its practicability, therefore, I do not wish to be confined to the preferred embodiment shown in th drawings and described herein.

I claim: 1. A humidifier, comprising: a vertically disposed casing forming a primary water holding chamber, said casing having an opening adjacent its upper limit to permit steam to issue from the water holding chamber; heater means within the depending end portion of said casing;

water supply 'means connected with the upper end portion of said casing;

tube means connected with the depending end portion of said casing and forming a secondary water holding chamber limiting the quantity of water contained by said casing;

thermal switch means connected with the wall of the depending end portion of said casing and operatively connected with said water supply means for refilling said casing at predetermined intervals; and,

themial conduction means interposed between said switch means and said casing wall for increasing the thermal inertia of said switch means.

2. The humidifier according to claim 1 in which said heater means comprises: 7

a downwardly open housing coaxially received in close spaced relation within the depending end portion of said casing; and,

an electrical resistance heating element within said housing.

I 3. The humidifier according to claim'2 in which said water a water supply pipe; a solenoid valve interposed in said water supply pipe; and, wiring connecting a source of electrical energy with said heating element, 1 said solenoid valve and said thermal switch means.

4. The humidifier according to claim 3 in which said tube means comprises:

a first tube substantially defining a U-shape and having an upwardly open leg portion extending upwardly substantially coextensive with said casing; and,

a second tube horizontally connected, at one end, with said first tube above the upper limit of said housing,

the other end of said second tube projecting downwardly. 5. The humidifier according to claim 4and further including:

normally open float valve and cage means coaxially connected with theupper end portion of said casing and said first tube leg portion, respectively.