US3675351A

US3675351A - Steam iron and valve structure

Info

Publication number: US3675351A
Application number: US878840A
Authority: US
Inventors: Arthur C Downing
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1969-11-21
Filing date: 1969-11-21
Publication date: 1972-07-11
Anticipated expiration: 1989-07-11
Also published as: DE2057247B2; DE2057247A1; GB1323605A

Abstract

The invention discloses a steam iron wherein the usual control valve, regulating water flow from the water tank to the steam generating cavity, is of a non-metallic, low heat conductive material such as ceramic to eliminate the steam dome and result in better and faster steaming.

Description

United States Patent Downing 1 July 11, 1972 [54] STEAM IRON AND VALVE STRUCTURE [72] Inventor: Arthur C. Downing, Ontario, Calif.

[73] Assignee: General Electric Company 221 Filed: Nov. 21, 1969 [21] Appl. No.: 878,840

[52] US. Cl ..38/77.83 [51] Int. Cl. ..D06t 75/06 [58] Field Search ..38/77.5, 77.7, 77.83

[56] Relereuces Cited UNITED STATES PATENTS 3,218,742 11/1965 Carabet et a1. ..38/77.5

Denton v.38/7783 Tisdale et al ..38/77.83 X

Primary ExaminerPatrick D. Lawson Attorney-Lawrence R. Kempton, Leonard J. Platt, John F. Cullen, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman ABSTRACT The invention discloses a steam iron wherein the usual control valve, regulating water flow from the water tank to the steam generating cavity, is of a non-metallic, low heat conductive material such as ceramic to eliminate the steam dome and result in better and faster steaming.

ZCMmSDruwingFlguns PATENTEDJUL H r972 Inventor Arthur C. Dowm r g bjg flL Qtwm g STEAM IRON AND VALVE STRUCTURE BACKGROUND OF THE INVENTION 1 Field of the invention This invention is directed to a steam iron and, more particularly, to an improved control valve construction between the water tank and steam generating cavity wherein the valve is preferably a ceramic valve to reduce the number of parts needed and improve the steaming performance of the iron.

2. Description of the prior art.

In most steam irons, steam is generated in a small cavity in the soleplate and subsequently distributed under pressure to apertures in the soleplate and to the fabric being ironed. In such irons, it is customary to support a water tank in a suitable manner within the iron and typically it is supported at its forward end by a steam dome that is generally made of stainless steel. The steam dome forms a part of a boiler coverplate that is secured to the soleplate and overlies and encloses soleplate cavities to form chambers where steam is generated and distributed. A stainless steel steam dome is usually used to reduce heat transfer to the water tank so that the water does not boil within the tank when the iron is operating in a dry condition. Water flow from the tank into the steam generating cavity is through a small orifice in a brass valve body, with the valve body typically secured to the steam dome. Careful selection of the different metallic materials is required to avoid serious corrosion problems with the aluminum components in the presence of moisture. Such corrosion changes the size of small orifices and corrosion flakes can clog the orifices resulting in poor or no performance in the steaming position.

Such conventional structure uses several relatively costly components, such as a stainless steel dome and brass valve body. Further, the valve body itself, when made of brass has generally been a costly machined part. Less expensive materials, such as aluminum, cannot be used with a brass tank because of corrosion problems.

The prior art construction has thus used several parts which can be improved by a new design that performs the same function with fewer and cheaper parts and eliminates corrosion problems.

SUMMARY OF THE INVENTION Briefly described, the present invention is directed to a steam iron that has a soleplate with a steam generating cavity and a distributing cavity connected to steam discharge apertures for steaming operation. The iron has a water tank and a control valve assembly that regulates water flow from the tank to the generating cavity. In this structure, the invention provides an improvement in the control valve assembly regulating structure by supplying a coverplate over the cavities to form chambers with the soleplate. The control valve body is formed of a non-metallic low heat conductive material, such as a ceramic, that is disposed directly in the coverplate in an opening formed therein that is shaped to conform to a portion of the valve body. The valve body is provided with an exit that opens to extend toward or into the generating cavity and it has an opposite entrance that is preferably disposed directly in the bottom of the water tank. Suitable sealing means between the valve body and tank, and between the valve body and coverplate provide liquid tight connections to permit the complete elimination of the steam dome. Thus, the main object of the invention is an improved control valve assembly structure that eliminates one of the conventional elements to reduce cost and elimination of a corrosion problem as well as permitting the use of a thicker, lower conducting and much stronger component by use of a non-metallic valve body.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation, partially in section and broken away, showing the location of the invention in a flat iron;

FIG. 2 is a partial sectional view of the improved cover-plate; and

FIG. 3 is an enlarged view of the individual valve body.

Referring to FIG. I, there is shown a typical flatiron of the type to which this invention may be applied, comprising a smoothing member or soleplate 10, a cover [2 enclosing various components within the iron, and an operating handle 14 molded from a thermal insulating material. Electric power may be supplied to the iron through a conventional cord, not shown, which enters the iron at the handle by means of a cord lift bushing 16. In order to adapt the iron for application to various fabrics, a temperature selector 18 is provided adjacent the top forward portion of handle 14 for convenience of the operator in selecting the desired operating temperature. Also, the iron is provided with a push button 20 or the equivalent which can be operated, for example, by an up-and-down motion to convert the iron from dry to steam operation or vice versa in a generally well-known manner.

Thermostatic switches for controlling operating temperatures of a flatiron are well-known in the art. In this particular embodiment, the temperature responsive element is in the form of a bimetallic blade 22 firmly secured to the flatiron soleplate 10 by means of a bolt 24. Such bi-metallic blades, in a well-known manner, exhibit the characteristic of deforming or bending responsive to heat. In this particular instance, blade 22 is mounted so that it will bend or deform downwardly responsive to increasing temperature of the soleplate. A compensating blade, not shown, is provided to even out the variations in temperature while the iron is coming up to steady state operating conditions as set by selector 18. The structure thus far described is conventional and is fully shown in US. Pat. No. 3,188,757 of common assignment.

The present invention is of particular importance with respect to its application in a combination steam and dry iron in which steam is generated in a flash steam generating cavity formed in the soleplate. A typical form of such a steam generating system includes a liquid reservoir in the form of a water tank 26 enclosed within cover 12 and which is supported in any suitable manner as will be described. For steam operation, the water in tank 26 is dripped through a control valve assembly, generally indicated at 28, into the steam generating cavity 30 formed in the soleplate where it flashes into steam. Generated steam is directed through a distribution cavity 32 which, in turn, is connected to steam discharge apertures 34 in the soleplate to steam the fabric being ironed. The steam is confined by a coverplate 36 which overlies the cavities to form chambers with the soleplate and thus confine the steam and distribute it in a known manner.

In accordance with conventional practice prior to this invention, the construction has used a so-called steam dome between the water tank and soleplate with the metallic control valve structure 28 located in the steam dome. The steam dome has generally been stainless steel to reduce heat transfer to the liquid in tank 26 and prevent boiling of water in the tank. Normally, this steam dome formed a part of the coverplate 36 and the metallic valve structure 28 was disposed in this intermediate steam dome structure as shown in the above referenced US. Pat. No. 3,188,757.

In accordance with this invention, the control valve regulating structure has been improved by omitting the previously used intermediate steam dome thus reducing the manufacturing cost. In addition, this invention provides a low cost replacement for the more costly machined brass valve body. The valve body made of brass in past constructions could not be placed in direct contact with the aluminum cover plate 36 because electrolytic corrosion attacks the aluminum with resultant bad effects on the small passages. Similarly, a brass valve body could not be used with an aluminum tank, and an aluminum valve body has not been satisfactory.

The valve body 38 according to this invention is formed of a non-metallic, low heat conductive material such as ceramic to both reduce cost and prevent corrosion. Valve body 38, as seen in FIG. 3, is provided with orifice 40 and water exit 42 at one end directed into generating cavity 30 and a water entrance 44 at the other end preferably disposed directly in the bottom of tank 26 as seen in FIG. 1. The usual spring-biased valve stem 46 controls orifice 40 for steam or dry operation as actuated by button 20.

In order to accommodate ceramic valve body 38, as seen in H0. 2, coverplate 36 is formed with an opening 48 therein that is shaped to confon'n to a portion of the valve as seen in FIGS. 1 and 3 and the valve is seated directly in opening 48 to extend toward the generating cavity as shown in FIG. I. Suitable sealing means, such as silicone elastomer gaskets 50, are used to seal the valve body between the tank and the coverplate and directly to each as shown.

Since the non-metallic and low heat conductive ceramic valve body is used, it is possible to use a thicker and thus stronger body with no additional heat transfer and to dispense with the intennediate stainless steel dome. Thus, the water tank is directly connected to valve body 38 and held down by a bracket 52 secured to the coverplate by screw 54. The nonmetallic such as a ceramic valve body for the same wall thickness provides better thermal isolation than a metallic or stainless steel dome. At the same time, the non-metallic valve body can be used in direct proximity to the metal tank and metal coverplate without danger of corrosion and regardless of the type of metal or alloy used in the other parts of the iron. Further, it should be noted that the phenomenon drifilm" which blocks water flow through a valve body when a film prevents water from wetting the internal surface is not increased and indeed, may even be decreased, because a ceramic presents an easily wettable surface. Since the ceramic is a good insulator much thicker and thus stronger wall sections may be used without any additional heat being transmitted between the hot soleplate and the water tank. Further, the ceramic part is substantially lower in cost The present structure thus provides the necessary insulation between the parts, completely eliminates the expensive steam dome, and eliminates corrosion to result in better operating iron.

While there has been described a preferred form of the invention, obvious equivalent variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practised, otherwise then as specifically described, and the claims are intended to cover such equivalent variations.

lclaim:

1. in a steam iron having a soleplate with a steam generating cavity and a distributing cavity connected to steam discharge apertures, a water tank and a control valve assembly regulating water flow from said tank to the generating cavity, the improvement in control valve regulating structure comprising;

a coverplate over said cavities to form chambers thereof with the soleplate,

said control valve having a body formed of a ceramic material and disposed directly in said coverplate,

said body having an exit at one end into said generating cavity and an entrance at the other end into said tank, and means sealing said valve between said tank and said coverplate.

2. Apparatus as described in claim 1 wherein said coverplate is formed with an opening therein shaped to conform to a portion of said valve body,

said valve being seated directly in said opening to extend toward said generating cavity,

said entrance in the valve body being disposed in the bottom of said tank, and

said sealing means sealing said valve directly to said tank and said coverplate.

k I I! l 1* a less costly and

Claims

1. In a steam iron having a soleplate with a steam generating cavity and a distributing cavity connected to steam discharge apertures, a water tank and a control valve assembly regulating water flow from said tank to the generating cavity, the improvement in control valve regulating structure comprising; a coverplate over said cavities to form chambers thereof with the soleplate, said control valve having a body formed of a ceramic maTerial and disposed directly in said coverplate, said body having an exit at one end into said generating cavity and an entrance at the other end into said tank, and means sealing said valve between said tank and said coverplate.

2. Apparatus as described in claim 1 wherein said coverplate is formed with an opening therein shaped to conform to a portion of said valve body, said valve being seated directly in said opening to extend toward said generating cavity, said entrance in the valve body being disposed in the bottom of said tank, and said sealing means sealing said valve directly to said tank and said coverplate.