US2097582A - Electric steam generator - Google Patents

Description

Patented Nov. 2, 1937 UNITED STATES PATENT OFFlCE tric Steam Sterilizing Company, Inc.,

New

York, N. Y., a corporation of Delaware Application March 31, 1936, Serial No. 71,883

-11 Claims.

This invention is directed to an improvement in electric steam generators, and has for one of 'its vobjects the provision of such an apparatus which will be compact, involve no moving parts, relatively inexpensive to manufacture and of 'long life.

Generally speaking my invention provides an apparatus in Whichfeedwater is supplied Vto the top of the apparatus, Vwhile the steam outlet Vmay be either at the top or bottom of the apparatus.

` My improved apparatus embodies a metal mass into which/the heating velement is cast, this mass surrounding the evaporating surface, which takes the form of a metal casting extending into the metal mass and provided with a downwardly inclined groove extending helically about the periphery of the casting, means being provided for conducting the generated steam upwardly through the center of the generator to an outlet near the top thereof,

Means are provided adjacent the feedwater inlet for `automatic temperature control of the metal mass, this 'device comprising a thermostat functioning to maintain the metal mass within a predetermined temperature range and to close an electric circuit to the heating element `when feedwater is supplied to the apparatus.

I alzso vprovide in my improved apparatus for reducing the thermal conductivity of the metal mass adjacent thefeedwater inlet, which aids in reducing objectionable bumping and surging when my apparatus is in operation.

In the accompanying drawing:

Fig. l is a sectional elevational view of .an embodiment of my invention;

Fig. 2 is a plan view;

Fig. 3 is a section on the line 3 3 of Fig. .1; and

Fig. 4 is a sectional elevational view of the temperature control apparatus.

Referring to the drawing in detail, I designates a mass of metal, cylindrical, for example, in shape, provided with a groove 2 extending helieally of the casting. This metal mass is slightly tapered and is enclosed by a pressure proof metal shell 3 in such a manner that a downwardly exftending channel for the iluid to be evaporated is yprovided. Means are provided for conducting the generated steam upwardly to an outlet near the top of the shell '3 as will be'brought out hereinafter.

The top of the shell '3 is provided with a'lower wall 4 and upper wall 5 spaced slightly from each Vother to provide for the oW of Water entering the apparatus through inlet 6 before the same enters theevaporating'channel above referred to.

These walls are so shaped as to provide a Well 'I in which is mounted the thermostatic control device shown in Fig. 4 and which will be described in detail hereinafter. By passing the feedwater between the two walls I and 5 the thermostat will be cooled down to insure closing of the electric circuit of the heating element of my generator whenever ieedwater is supplied.

The general shape of the shell 3 is cylindrical and tap-ered and it ts into a hole of te same taper in the heater casting. This heater easting comprises a. metal mass S into which is east the heating element 9.

This arrangement provides goed contact between all heat conducting parts and insures excellent heat conductivity.

The evaporating surface provided by the arrangement of the grooved casting I and shell 3 is in communication with a central channel iii in the casting to the upper end of which is connected the steam outlet tubing I I. This tubing is led around the assembled parts for about three quarters of a turn to relieve any stresses set up by temperature changes and is then led to the outside of the apparatus. This tubing is interrupted intermediate its ends for the insertion of pyrex glass tubing i2 to reduce heat losses caused by a continuous copper tubing.

The shell 3, mass I and the thermostatic control are held in place by cross member lil and screws I5.

l5 designates a collar slipped over shell 3 before the same is placed in position. This collar is provided with screws I'l and when the same are screwed down collar IS will be raised to lift shell 3, metal mass I and thermostatic control apparatus out of the heater casting 8 for inspection and repair.

At the top of the heater casting I provide a pyrex cylinder or sleeve I8. This sleeve is Jdared toward its upper end to receive a pyreX container I9 iilled with magnesia.

The assembly, i. e., metal mass I, shell 3 and the heater casting 8, is packed in inagnesia or other suitable heat insulation 2Q in a vacuum jar 2 I, the latter being packed in heat insulating material 22 in a sealed casing 23.

It will be seen from the drawing that the feedwater inlet and steam outlet are brought through thetop of the casing or container 23.

The leads for the electric heating element are brought from the outside of the apparatus and are designated 24 and 25, One ci these leads goes to the heating element direct, the other through` fusible Vlink 26 and the thermostat oi Fig. 4 to the heating element.

This thermostat, which is a well known commercial article, comprises a disc 2l carrying contacts 28, cooperating wih contacts 29 on a bie- 'metal disc 33.

The cold position of this dise is shown in dotted lines in Fig. 4. While this therscribed, the thermostat will close to close the electric circuit of the heating element.

To reduce the thermal conductivity o f the metal mass l adjacent Vthe feedwater inlet, I

groove thesame as shown at 3| and fill this V groove with asbestos, magnesia or other suitable' l tion of steam. That the apparatus while automatically controlled has no moving parts at all with the exception of the dished bimetal disc 3E, and that repairs and renewals are easily made.

' It is to be understood that changes may be made in the details of construction and arrangement of parts within the purview of my invention. l

What-I claim is:-

1. An .electric steam generator comprising in combination a metal mass with a heater cast therein, said mass being provided with a central chamber, a metal shell tting said chamber, and a second Ymetal mass provided with a grooved periphery fitting within said shell, the said'groove Vin conjunction with said shell providing evaporating surfaces for the generation of steam.

2. An electric steam generator comprising in combination V,aV metal mass with a heater cast therein, said mass being provided with a central chamber, a metal shell fitting said chamber, and a second metal mass provided with a grooved Y periphery fitting within said shell, the said groove in conjunction with said shell providing evaporating surfaces for the generation of steam, said second metal mass being provided with a central longitudinal passageway for the passage of steam upwardly of the apparatus.

3. An electric steam generator comprising in combination a metal mass with a heater' cast therein, said mass being provided with a central chamber, a metal shell tting said chamber, and a second metal mass provided with a downwardly extending groove on its periphery fitting within said shell, the said groove in conjunction with said shellV providing evaporating surfaces for the generation of steam. V

4. An electric steam generator comprising ,in combination a metal mass with va heater cast therein, a metal shell tting into a chamber in said casting, a second metal mass fitting into said shell, the periphery of said second metal mass being provided with a groove extending helically about its periphery and a feedwater inlet at the 1Lipper end of said groove, saidV shell and second metalmass being removable as a unit from the heater casting.

5. An electric steamV generator comprising in combination a metal mass with a heater cast therein, a metal shell fitting into said casting, a

. secondV metalmass with a grooved periphery tting into said shell, a feedwater inlet connectedY to the upper end of said groove, said second metal mass being provided with a passageway Vextending from bottom to top of the same, and

a steam outlet at the upper end of said passageway.

combination a metal mass with a heater cast therein, a metal shell tting into a chamber in said casting, a grooved second metal mass fit- 6. An electric steam generator comprising in` ting into said shell, a feedwater inlet at 'the upper end of said groovefand an automatically oper- Y extending downwardly and in conjunction with said shell providing an evaporating surface, a passageway for steam extendingrfrom the bottom to the-top of said metal mass, a steam outlet connected to the upper end of said passageway, a

thermostat adjacent the upper end of said metal mass forpcontrolling the circuit of said heating element, and metal tubing constituting a feed- Vwater inlet coiled about said casting and connected to the upper end of saidrgroove.Y

8. An electric steam generator comprisingin combination a metal heater casting, a heater element embedded therein, a metal shell tting into said casting, a Vmetal mass tting into said shell, the periphery of said metal mass being p-rovided with a helically extending groove coperating with said shell to provide an evaporating surface, a double walled top for said shell,

said walls being 'spaced apart to provide a passageway for feedwater communicating with said evaporating surface, and a thermostat for controlling the circuit of said heater located immediately above the upper of said walls, whereby admission of feedwater to the apparatus will soY effect operation or" said thermostat to close the circuit of the heater element. Y

9. An electric steam generator comprising in combination a heater casting, a metal shell fitting into said casting, a metal mass tting into said shell, said metal mass being provided with a helically extending groove in its periphery, the said groove cooperating with said shell to provide an evaporating surface, said mass being provided with a passageway extending from bottom= to top of said metal mass, the lower'end of said passageway communicatingV withY said evaporating sur- Y face, a thermostat adjacent the upper end of the apparatus and supported thereby for controlling the electric circuit of theheater, said thermostat, metal mass and shell being removable as a unit.

10.r An electric steam generator comprising in combination a metal mass witha heater cast therein, said mass being providedwith a central chamber, a metal shell fitting said chamber, and a second metal mass provided with a grooved k periphery fitting within said shell, the said groove in conjunction with said shell providing evaporating surfaces for the generation of steam, heat insulation for said apparatus and an enclosing vacuum jar. l Y

11. An electric steam generator comprising in combination a metal mass with a heater cast therein, a metal shell fitting into a chamber in said casting, a grooved second metal mass fitting into said shell, a feedwater inlet at the upperV end of said groove, an automatically operable control device adjacent the feedwater inlet for controlling the electric circuit of the heater, and

a fuse operable to open the circuit of the heater on an excessive temperature rise in the apparatus.

Y KURT BEYRODT.

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