Electrically heated steam treatment device

Claim 2

A heating device comprising: a frame, a heat chamber in said frame having an metallic enclosure and an opening in one side thereof for receiving material to be heated and a closure door for sealingly closing said opening, latch means for latching said closure door closed, heat insulating material in said frame surrounding said metalic enclosure on all sides except the side having said opening, water supply means leading into said chamber for supplying water thereto and a fill valve therein, control means for controlling said fill valve to maintain the water in said chamber at a predetermined level, electrical heating means disposed in a relationship with said metallic enclosure for heating the water to generate steam in said chamber, relief valve means leading from said chamber to the atmosphere for maintaining a predetermined pressure on the steam in said chamber, a drain line leading from said chamber to drain liquid therefrom and a drain valve therein, and means to automatically open said drain valve when said heating means is deenergized, and said closure door being openable only when said heating means is deenergized.

Claim 3

A heating device according to claim 1 which includes a lock means operable for locking said latch means in latching position, and means for releasing said lock means to permit unlatching and opening of said closure door and operable only while said heating means is deenergized.

Claim 4

A heating device according to claim 2, which includes means for preventing energization of said heating means and opening of said fill valve except when said closure door is closed and latched.

Claim 5

A heating device according to claim 1, in which said control means comprising means for opening said fill valve to cause water to be supplied to said chamber and means responsive to said predetermined liquid level in said chamber for closing said fill valve. 5 A heating device according to claim 4, in which said frame includes a space therein at one side of said chamber and said drain and fill valves being mounted in said space.

Claim 6

A heating device according to claim 4, in which said metallic enclosure comprises top, bottom, back and sidewalls and open at the front, said sidewalls each comprising an outer wall and an inner wall spaced inwardly from the respective outer wall, each said inner wall at the bottom being formed to permit fluid flow between opposite sides thereof, said closure door closing the open front of said metallic enclosure when closed, and a wall member extending upwardly from the bottom wall of said metallic enclosure at the front of said metallic enclosure to a level higher than said predetermined liquid level.

Claim 7

A heating device according to claim 6, in which said supply conduit leads into said chamber between a said outer wall thereof and the adjacent inner wall, and said inner walls having support means on the sides thereof facing each other for supporting a heating vessel at a level above said predetermined liquid level.

Claim 8

A heating device according to claim 6, in which the chamber between said inner walls operates at negative pressure during at least a portion of the cycle.

Claim 9

A heating device according to claim 1, in which each said relief valve means comprises a tube leading from said chamber upwardly through the top wall of said device, a valve member of predetermined weight resting on the upper end of said tube, and retaining means retaining said valve member captive in the region of the upper end of said tube.

Claim 10

A heating device according to claim 9, in which said retaining means is in the form of inner and outer sleeve elements concentric with each other and with at least the upper end of said tube and mounted on the top wall of said device, said inner sleeve element having radial clearance from said valve member and extending to a level above said valve member, said outer sleeve having radial clearance from said inner sleeve and extending to a level above the upper end of said inner sleeve and having a perforated closure on the upper end, a porous disc of sound deadening material interposed between said perforated closure and the upper end of said inner sleeve, and a sleeve of sound deadening material interposed between said sleeve elements.

Claim 11

A heating device according to claim 1, in which said water supply means comprises a fill valve connected between a source of water and said chamber, a drain valve connected between said chamber and drain, a latch for latching said closure door in chamber closing position, a lock engageable with said latch to lock the latch in door-latching position, electric operators for said fill and drain valves and lock energizable for opening the respective valves and for releasing said lock, said heating means comprising electric resistance heating means, said timer being electrically operable, an energizing circuit and a main switch therein, a first switch having a blade connected to said main switch and having a first position in circuit with the said fill valve operator, said control means including a control circuit with the said fill valve operator, said control means including a control circuit including a second switch in said chamber responsive to the water reaching said predetermined level therein for causing the blade of said first switch to move to a second position, relay means energizable in response to movement of said blade into said second position and operable for initiating a supply of energy to said heating means and timer, means responsive to the elapse of the period for which said time is set for deenergizing said relay means for disconnecting the blade of said first switch from said main switch and for connecting the said operation for said lock and said drain valve to said main switch.

Claim 12

A heating device according to claim 11, which includes a normally open limit switch in series with said main switch and operated into closed position by actuation of said latch into door-latching position.

Claim 13

A heating device according to claim 11, which includes signal lights on said device connected for energization simultaneously with said heating means and drain valve operator, respectively.

Claim 14

A heating device according to claim 11, in which said control circuit comprises a stepdown transformer having its primary coil connected to said main switch, a rectifier connected to the secondary coil of said transformer, and a coil energizable for actuating the blade of said first switch from its first to its second position, and connected in circuit with said rectifier and said second switch, said second switch completing a circuit through said coil when the water level in said chamber means reaches said predetermined level.

Claim 15

A heating device according to claim 14, in which said relay means includes a holding circuit so that once energized it will remain energized until said timer times out, whereby the blade of said first switch can move to and from its said first position to maintain the water level in said chamber as may be determined by the operation of said second switch without influencing said relay means.

Claim 16

A heating device according to claim 15, which includes thermostatically controlled switch means in series with said heating means operable to control the supply of energy to said heating means and thereby control the rate of heat supply to the water in said chamber.

Claim 17

A heating device according to claim 1, in which said electrical heating means is in the form of electric resistance heating elements mounted on the underside of the bottom wall of said metallic enclosure.

Claim 18

A heating device according to claim 1 including an adjustable timer meAns operatively connected to said heating means for controlling the energization of said heating means to determine the length of a heating cycle.