US1715687A

US1715687A - Thermostatically-controlled fluid heater

Info

Publication number: US1715687A
Application number: US227416A
Authority: US
Inventors: Victor G Vaughan
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1927-10-20
Filing date: 1927-10-20
Publication date: 1929-06-04
Anticipated expiration: 1946-06-04

Description

J1me 1929- v. G. VAUGHAN THERMOSTATICALLY CONTROLLED FLUID HEATER Filed Oct. 20, 1927 INVENTOR Vz'ctor G. Vaughan.

ATTORNEY Patented June 4, 1929.

UNITED STATES PATENT OFFICE.

VICTOR G. VAUGHAN, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

THERMOSTATICALLY-CONTROLLED FLUID HEATER.

Application filed October 20, 1927. Serial No. 227,416.

My invention relates to immersion electric fluid heaters and particularly to heaters oi the thermostatically controlled type.

An object of my invention is to provldea thermostatically controlled immersion fluid heater that shall be simple in construction and easily manufactured.

A further object of my invention is to provide a thermostatically controlled heater that shall be operable to maintain the temperature of a fluid to be heated thereby substantially constant, and that shall be operable to protect the heating element from overheating in the event that it is not submerged in flui In practicing my invention I provide a closure member for a conduit, to which a sheathed electric heating element is secured in thermal relation therewith. The heating element is adapted to be placed in the conduit and the opening through which it is inserted to be closed by the closure member.

In order'that the heating element may be protected from over-heating, and that the temperature of fluid flowing through the conduit may be controlled, a thermostatic switch for controlling the heating element is mounted in a cup portion of the closure member.

For a fuller understanding of my invention, reference may be had to the following description, taken in conjunction with the accompanying drawings, in which:

' trated in Figs. 1 and 2,

Figure l is a partial view, artially in section, of a fluid tank and a t ermostatically controlled heating unit for heating fluids stored in the tank,

Fig. 2 is a view, in section, taken on line 11-11 of Fig. 1,

Fig. 3 is an edge view of a switch-supporting member embodied in the device illus- Fig. 4 is a view, in section, taken on line IVIVof Fig. 3, and

Fig. 5 is a schematic illustration of the circuit connection of the heating element and the thermostatic switch embodied in the device of Figs. 1 and 2.

In the drawings, an open-end pipe fitting 1 is illustrated that is provided with an internally screw-threaded opening 2 that has screw-threaded engagement with a pipe 3 extending from the top of a tank 4-.

The lower end of the tank is prov ded w th a pipe 5, to the outer end of which a pipe fitting 6 is connected. The lower end of the pipe fitting 6 is provided with a plug 7 that has screw-thread engagement with an internally screw-threaded opening in the bottom thereof through which fluid may be drained.

The pipe fittings 1 and 6 are connected by a conduit 8 that has screw-thread engagement with the adjacent open ends of the fittings. Thus, it is seenthat a passagewa for the circulation of fluid from the tan through the pipe 5, the conduit 8 and the pipe 3 to the upper end of the tank 4 is provided.

The upper end of the pipe fitting 1 is provided with a closuremember 9 of substantially cup-shape. A gasket'lO is disposed between the rim of the closure member 9 and the upper end of the pipe fitting 1, in order that a fluid-tight joint may be provided when the closure memberis secured to the pipe fitting by means of bolts 11.

A tubular heating element 12 of substantially hairpin shape is supported by the closure member 9, the ends of the heating element extending upwardly through the rim of the closure member and in contact with the sides of the cup portion of the closure member.

The tubular heating element may be secured intimately thereto by brazing, or, in some instances, the heating element may be cast in the closure member. As is shown in Fig. 1 of the drawings, the tubular heating element 12 extends downwardly throu h the conduit 8, so that if the fluid level in the tank 4 is above the level of the pipe 3, the geagingelement will be submerged in the In order that the temperature of fluid in the tank 4 may be controlled or maintained at a substantially constant value, and in order that the heating element 12 may be protected from overheating in the event that the water level in the tank 4; becomes lower than the level of the pi e 3, a thermostatic switch 13 is provided, t e switch being lo- Fig. 5), secured to one face of the base.

The contacts 15 to 19 may be insulated from the base 14 by a sheet of insulation 21. The contaCt l5 and 1. are provided with

terminals

22 and 23 that are secured on the opposite face of the base 14. Y

The stationary contacts 15 to 19, inclusive, cooperate with relatively movable contacts or bridging members 24 to 27, inclusive, that are carried by, a temperature-responsive bimetallic disc 28, but suitably insulated therefrom. The disc 28 is secured to the base 14 by an adjustable supporting stud 29.

As is shown in Fig. 5, the discs 24 to 27, inclusive, engage and bridge adjacent ends of the stationary contact members 15 to 19, inclusive. When the disc 28 is in the position shown in Fig. 1 of the drawings, an electric circuit may be completed between the

terminals

22 and 23 of the switch.

The switch 13, embodying the bimetallic disc 28, is preferably of the type disclosed in the U. S. Patent 1,448,240 to J. A. Spencer. The disc there disclosed has the characteristic that, when normally cool, the movable contacts or bridging members 24 to 27, inclusive, engage the stationary contact members 15 to 19, inclusive, but, when heated to a temperature of a predetermined value, the disc suddenly changes its shape with a snap motion, thereby causing disengagement of the contact members. If the disc is subsequently cooled to a lower temperature of a predetermined value, the disc again assumes its initial shape with a snap motion, thereby causing re-engagement of the contact members.

The base 14 of the thermostatic switch is disposed between

lugs

31, 32, 33 and 34 that are integral with a resilient clamping and supporting member 35. The member 35 is provided with

extensions

36 and 37 having

portions

38 and 39 extending laterally therefrom. The laterally extending

portions

38 and 39 are disposed to rest on the upper face of the rim portion of the closure member 9, they clamping member being provided with screws 41 for securing it to the rim thereof.

One terminal of the tubular heating element 12 is connected, by a condctor 43, to the terminal 22 of the thermostatic switch,

' and the terminal 23 thereof is connected,

by a conductor 44, to a manually-operable snap switch 45. The other terminal of the tubular heating element 12 is connected, by a conductor 46, to the snap switch 45.

The snap switch 45 is supported by a resilient bracket 47 that is secured to the edge of the rim portion of the closure member 9. The terminals of the tubular heating element and the conductor leading from the thermostatic switch to the snap switch 45, maybe enclosed by a cover 48 which is secured to the bracket 47. Electrical connectionmay be made to the snap switch from a source of electromotive force, by means of conductors located in a conduit 49 that extends through one wall of the cover 48.

Assuming that the tank 4 contains a sufliamass? cient quantity of water so that the level thereof is above the pipe 3, and assuming also that the tubular heating element 12 is connected to a source of electromotive force, fluid contained within the conduit 8 and the pipe fitting 1 will be heated by the heating element. The heating of the fluid will cause it to circulate from the tank through pipe 5, upwardly through the conduit 8, through the pipe 3 and into the tank 4. So long as the tubular heating element is energized, the fluid will'continue to circulate, in a manner well known in the art, until the temperature of the fluid passing through the conduit 8 and about the cup portion of the closure member 9, will have reached a temperature of a predetermined value. At this temperature, the thermostatic switch will operate to 'deenergize the heating element 12.

When the temperature of the fluid has fallen to a predetermined value, the thermostatic switch will operate to reenergize the heating element. In the event that the level of the fluid falls below that of the pipe 3, or in the event that no fluid remains about the heating element 12, andthe heating elements are connected to a source of electromotive force, the closure member 9 will be heated to the temperature at which the thermostatic switch 13 effects deenergization of the tubular heating element 12 in a relatively short period of time, thereby preventing the t-ubular heating element from reaching an excessive or injurious temperature.

It is to be seen from the drawings that, since the cup portion of the closure member 9 extends into the pipe fitting 1 and since the tubular heating element 12 is in direct thermal contact therewith, the thermostatic switch will function both to protect the heating element 12 in the event no fluid circulates about the heating element and to control the temperature of the fluid circulating thereabout when the level of the fluid in the tank 4 is above that of the pipe 3.

Since the thermostatic switch, the tubular heating element 12 and the closure member may be manufactured as a single compact unit, the heating element ma be withdrawn from the conduit 8 easily an quickly by removing the bolts 11 after the cover 48 has been removed from the supporting bracket 47. Thus, the heating element 12 may be repaired or replaced with facility.

Various modifications may be made in the device embodying my invention without departing from the spirit and scope thereof. I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and the appended claims.

I claim as my invention:

1. In a fluid heater, the combination with a conduit having inlet and outlet ports, a heating element disposed in said conduit, and a thermostatic switch for controlling said heating element, of a closure member having a portion of cup-shape extending into said conduit for supporting said heating element and thermostatic switch in thermal relation with each other, said thermostatic switch being disposedyin the portion of cup shape.

2. A thermostatically controlled heating unit adapted to be inserted in a conduit of a fluid-circulating system, comprising a closure member of substantially cup-shape for a conduit, a sheathed electric heating element extending through the rim and along the walls of said member of cup-shape, a portion of said heatin element having intimate thermal contact wlth said closure member, and a. thermostatic circuit-controlling device disposed in the cup of-said closure member in thermal relation therewith for controlling the energization of said element.

3. The combination with a pipe fitting having inlet and outlet ports and adapted to be connected in fluid-circulating system, of a closure member of substantially cup-shape for said pipe fitting, a tubular heating e ement supported by said closure member and in thermal conductive relation therewith, and a thermostatic switch located in the cup portion of said closure member.

4. The combination with a pipe fitting having inlet and outlet ports and adapted to be connected in fluid-circulating system, of a closure member of substantially cup-she for said pipe fitting, a tubular heating ement supported by said closure member and in thermal conductive relation therewith, a resilient clamping member disposed in the cup portion of said closure member and secured thereto, and a thermostatic switch located in said cup portion and supported therein by said clamping member.

5. A. fluid heater comprising a conduit, a closure member for one end thereof, a sheathed heating element having the ends thereof integrally secured to said closure member, and a thermostat mounted on said closure member in thermal communication therewith for controlling said heating element in accordance with the temperature of said closure member. v

6. A fluid heater comprising a su port adapted to close an opening in a flui container, an enclosed heating element havin the terminal ends thereof integrally secure to the support, said heating element being located within the casing when said opening is closed by the support, and a thermostat mounted on said support in thermal communication therewith for controlling said heating element in accordance with the temperature of said support, said thermostat being located on the outside of the easing when the opening is closed by said support.

In testimony whereof, I have hereunto subscribed my name this 10 day of Oct. 1927.

VICTOR G. VAUGHAN.