US2257358A - Steam generator - Google Patents

Description

Sept. 30, 1941. F. WIGHTMAN STEAM GENERATOR Filed Aug. Q8, 1939 2 m4 W m m 3% E mm P F Patented Sept. 30, 1941 STEAM GENERATOR Frederick Wightman, Los Angeles, Calif., assignor to Walter B. Kerrick, Los Angeles, Calif.

Application August 28, 1939, Serial No. 292,259

' 11 Claims. (01.122-448) This invention relates generally to heat exchange apparatus, and more particularly to steam generators.

An object of the invention is to provide a steam generator which is structurally characterized by means insuring a supply" of dry steam under any and all operating loads up to the relatively large steaming capacity of the generator,

and in a manner to positively prevent the carrying over of water into the steam delivery line, all automatically and economically with respect to the consumption of fuel.

Another object of the invention is to provide a steam generator of the above described character which embodies an ebullition chamber and primary and secondary generating coils associated therewith and with the combustion chamber of the generator in such manner as to enable the supply of fuel and water to be accurately controlled automatically in accordance with the demand for steam which will be supplied in a dry state irrespective of the demand.

With these and other objects in view, the invention resides in the combinations, arrangements and functional relationships of elements as set forth in the following specification and.

particularly pointed out in the appended claims.

In the accompanying drawing the figure is a semi-diagrammatic view showing in vertical section one form of steam generator embodying the invention. V

Referring specifically to the drawing, the invention comprises a suitably insulated furnace In defining a combustion chamber I1. At the top of the front wall of the furnace is a fuel burner l2 which is illustrated as being of the type to burn a gaseous fuel delivered thereto from a suitable source of pressure supply through a pipe I3 having a valve ll adapted to be controlled automatically, as will be later described.

Suitably supported above the furnace I is a steam and water separator I5 in the form of a horizontally elongated metal shell adapted to safely withstand the maximum steam pressure to be generated.

The separator 15 is divided by a dam or partition I6 into an ebullition space l1 and a control space 18, the bottom of the separator in the ebullition space inclining downwardly from the dam. A steam generating coil I9 is supported in the combustion chamber H and is connected by a pipe,2fl to a reservoir 21 in which water is maintained at a" predetermined level by a floatoperated valve 22 which controls the delivery of water to the reservoir from a pipe 23 connected to a source of water supply under pressure.

By means of a pipe 24 the other end of the coil I9 is connected to the separator IS, the pipe 24 entering the top of the separator and extending downwardly therein at its lowermost end to a.

point below the minimum water level in the ebullition space 11. A suitable gage glass 25 is provided to indicate the water level in the space l1, and a pressure gage 26 is supported on the separator to indicate steam pressure therein.

A steam generating coil 21 is supported in the combustion chamber ll above the coil l9 so as to be disposed in the hottest zone of flame from the burner l2, 2. suitable flame spreader 28 being interposed between the burner and the coil 21. Thus, the flame from the burner intraveling downwardly in the combustion chamber, as indicated by the broken line arrows, first passes the coil 21 and then the coil 19, the residual gases discharging through a suitable flue 29 connected to the furnace at the bottom of the. chamber II.

The top horizontal branch 30 of the coil 21 is connected by a vertical pipe 3| to the separator l5 at the bottom ofthe control -space I8,

and a baffle 32 is interposed between the inlet provided by the pipe 3| and the steam outlet 33 connected to the top of the separator so as to communicate with the steam space 34 therein.

The lowermost branch of the coil 21 is connected by a vertical pipe 35 to the separator I5 at the lowermost end of the ebullition space I1 an ejector which functions in-a manner to be later described.

The aforementioned horizontal branch 30 of the coil 21 is constructed of brass or other metal having a. high co-efficient of expansion and constitutes a thermostat. At one end of the branch 30 is an extension 38 which seats against an adjusting screw 39, and at the other end of said branch is a rod 40 which engages the stem of the valve M to force the latter towards its closed position against the urging action of a spring 42, to open the valve.

A piston type force pump 43 is connected in circuit with the water pipe 20 and is driven by an electric motor 44 connected by conductors 45 and 46 to a source of current supply. The supply of current to the motor 44 is controlled by a manual switch 46 and a normally closed thermo- It Will I! to a level below the top of the dam l6, as can be determined by observing the gage glass 25. The pump is now shutdown by opening the manual switch 41.

The burner I2 is now lighted to heat the coils l9 and 21, the heat applied to the secondary coil 2! causing thermo-circulation to be efiected therein in the direction of the full line, arrows, it being noted that the water level in the ebullition space is higher than at the inlet of the pipe 3| to the bottom of the control space l8 so that uni-directional circulation in accordance with the arrows will be induced.

As heat from the burner is also being applied to the coil IS, the thermo-circulation will be accelerated by the discharge end of the pipe 25 24 and the pipe section 36 acting as an ejector.

By the combined natural and artificially ac celerated thermo-circulation, the temperature of the body of water in the ebullition space is increased to raise the steam pressure in the separator I to a predetermined amount in accordance with the adjustment of the thermostat control screw 39, to cause the thermostatic pipe branch 30 to so actuate the fuel valve l4 that I I level in the ebullition space, and an outlet for the flow of fuel to the burner will provide the requisite amount of heat to maintain a predetermined steam pressure in the separator.

The manual switch 41 is againclosed so as to place the pump 43 under the automatic control of the thermo-responsive switch 48.

Any excess water in'the ebullition space I! flowing over the dam IE or rising in the pipe 3| into the control space I8 is free to flow through thepipe 49 past the steam trap 50 and to discharge into the reservoir 2|, the heat of this 4 water re-acting upon the. thermo-responsive switch 48 to open same and thus stop the motor 44.

So long as there is suflicient demand for there be a rise or fall in steam pressure, the

temperature will rise or fall accordingly. Thus, under theaction of the thermo-expansive tube 30, more or less fuel'will be supplied to the burner I2 according as the demand for steam increases or decreases. p

The varying supply of fuel to the burner acts on the liquid in the primary coil is by heating the liquid to increase its volume and velocity to a greater orv lesser extent. Steam particles forming in the liquid at high temperatures drive the water particles from the discharge end oi. the coil IS with more or less force so as to accordingly accelerate the circulation in the coil generator. Thus the amount of steam generated in the secondary coil 21 will be increased or decreased to aid in maintaining a substantially constant pressure in the separator l5.

What is claimed is:

1; A steam generator comprising: a steam generating chamber having an ebullition space and a control space into which water in the ebullition space can flow when reaching a predetermined level; a heating coil having an inlet for said chamber communicating with the control space at a lower level than a normal water level in the ebullition space, and an outlet for said chamber communicating with the ebullition space at a location to be submerged by water therein, whereby when said coil is heated, thermal circulation through the coil will be eifected from said outlet to said inlet; means for supplying water to the ebullition space and including means co-actable with said outlet to accelerate the aforestated thermal circulation; means co-actable with said control space andwater supply means to maintain a supply oi.

water in the ebullition space irrespective of the demand for steam from said chamber; and

means for heating said coil to maintain a predetermined steam pressure in said chamber.

2. A steam generator comprising: a steam generating chamber having an ebullition space and a controlspace into which water in the ebullition space can flow when reaching a predetermined level; a heating coil having an inlet for said chamber communicating with the control space at a lower level than a normal water 0 fected from said outlet to said inlet; means for supplying water .to the ebullition space and including means co-actable with said outlet to accelerate the aforestated thermal circulation:

means responsive towater entering the control space from said inlet and/or the ebullition space to control said water supply means by preventing the delivery of an excess of water to the ebullition space; and means for heating said coil to maintain ,a predetermined steam pressure. in

said chamber.

3. A steam generator comprising: a steam generating chamber having an ebullition space and a control space into'which water in the ebullition space can flow when reaching a presaid chamber communicating with the ebullition space at a location to be submerged by water therein, whereby when said coil is heated. thermal circulation through the coil will be effected from said outlet to said inlet; a second heating coil having an inlet adapted'for 'connection to a source of water supply, and an outlet communicating with said chamber and co-actable with the aforestated outlet of the latter to accelerate the thermal circulation by v the action of water ,delivered'under pressure to the chamber; means responsive to water entering the control space from its inlet and/or the ebullition space to control the supply of water under pressure to the second said coilso as to prevent an excess otwater being delivered to the 2''! which latter-is in the hottest zone 01 the ebullition space; and means for heating said cells to maintain a predetermined steam pressure in said chamber. g

4. A steam generator comprising: a steam generating chamber having an ebullition space and a control space into which water in the ebullition space can flow when reaching a predetermined level; a heating coil having an inlet for said chamber communicating with the control space at a lower level than a normal water level in the ebullition space, and an outlet for said chamber communicating with the ebullition space at a location to be submerged by water therein, whereby when said coil is heated, thermal circulation through the coil will be effected from said outlet to said inlet; a, second heating coil having an inlet adapted for connection to a source of water supply, and an outlet communicating with said chamber and co-actable with the aforestated outlet of the latter to accelerate the thermal circulation by the action of water delivered under pressure to the chamber; a pump delivering water under pressure to the second said coil; a motor driving the pump; a circuit including a source of current supply, said motor and a switch; and means 'coactable with said switch and responsive to the heat of water entering said control space from its inlet and/or the ebullition space to so control the motor as to prevent an excess of water from being delivered to the ebullition space by the pump; means including a burner for heating said coils; and thermo-responsive means controlling the supply of fuel to the burner to maintain a predetermined chamber. t

5. A steam generator comprising: a furnace having a combustion chamber; means for generating heat in the combustion chamber; heating coils in the combustion chamber; a separator having a steam outlet; means connecting the inlet and outlet of one of said coils to the separator at locations to effect uni-directional thermal circulation through said one of the coils when heated; means connecting the inlet of the other of said coils to a source of water supply, and the outlet to said: separator at 'alocation to cause thermal circulation in said one of the coils to be accelerated by the discharge of fluid under pressure into the separator from the other of said coils; thermo-responsive means operatively associated with the combustion chamber to control the supply of fuel to said heat generating means to maintain steam pressure in the, separator; and means controlling the supply of water to the separator from said other coil by preventing the delivery of an excess amount of water to the separator.

76. A steam generator comprising: a furnace having a combustion chamber; means for generating heat in the combustion chamber; heating coils in the combustion chamber; a separator having a steam outlet; means connecting the inlet and outlet of one of said coils to the separator at locations to effect Juni-directional thermal circulation through said one of the coils when heated; means connecting the inlet of the other of said coils to a source of water supply, and the outlet to said separator at a location to co-act with the inlet of said one of the coils in defining an ejector accelerating the aforestated thermal circulation by the discharge of fluid under pressure from the other of said coils; means controlling the supply of fuel to the heat generating means to maintain steam pressure in thetseparato'r and means controlling the supply steampressure in said of water to the separator from said other coil by preventing the delivery of anexcess amount of water to the separator. j

7. A steam generator comprising: a furnace having a combustion chamber; means for generating heat in the combustion chamber; heating coils in the'eombustion chamber; a sepa-\ rator having a steam outlet; means connecting the inlet and outlet of one of said coils to the separator at locations to effect uni-directional thermal circulation through said one of the coils when heated; means, connecting the inlet of the other of said coils to a source of water supply, and the outlet to said separator at a location to cause thermal circulation in .said one of the coils to be accelerated by the discharge of fluid under pressure into the separator from the other of said coils; thermo-responsive means operatively associated with the combustion chamber to control the supply of fuel to said heat generating means to maintain steam pressure in the separator; a pump delivering water under pressure to said other coil; an electric motor driving the pump; an electric circuit including a source of current supply, the motor and a thermo-responsive switch for opening the circuit; and

means by which an excess of water in the separator will open said switch so as to automatically maintain a supply of water in the separator.

8.-A steam generator comprising a plurality of heating coils; heating meansfor said coils; means defining an ebullition chamber having a steam outlet; means connecting one of said coils in circuit with said chamber to effect thermal circulation therethrough upon heating of the coil; means for supplying water under pressure to the other of said coils; means connecting said other coil to the ebullition chamber at a location to accelerate the aforesaid thermal circulation under the action of water discharging from said other coil; means controlling said heating means to maintainsteam pressure in the ebullition chamber; and means controlling the water supplying means to maintain a supply of water in said chamber irrespective of the demand for steam.

9. A steam generator comprising: a steam generating chamber having an ebullition space and a control space into which water in the ebullition space can flow when reaching a predetermined level; a heating coil in a liquid circuit with the ebullition and control spaces, 'to effect thermo-circulation through the coil from the ebullition space to the control space; means for supplying water to the ebullition space and including means co-actable with said coil to accelerate the aforestated thermal circulation;

means co-actable with said control space and water supply means to maintain a supply of water in the ebullition space; and means for heating said coil to generate steam in the ebullition space. i

10. A steam generator comprising: a steam generating chamber having an ebullition space and a control space into which water in the circulation as water is supplied by the second coil to the ebullition space; means co-actahle with said control space and second coil to maintain a supply of water in the ebullition space; and means for heating said coils; to generate steam in the ebullition space.

11. A steam generator comprising: a thermocirculatory coil; an accelerating coil; a source of heat for the coils supplying more heat to the thermo-circulatory coil; means defining an ebu1- lition chamber having a steam outletand its water level above the level of the -the:rmb-cir-' culatory coil; means connecting the thermoicirculatory coil in circuit with said chamber at points below the water level therein to. effect thermal circulation therethrough upon heating of the coil; means for supplying water under pressure to one end of the accelerating coil; and means through which fluid is conducted from the other end of the accelerating coil to the ebullition chamber and downwardly to a point therein, from which the fluid will, by its velocity and. weight, discharge into an end of the thermocirculatory coil so as to act to accelerate the FREDERICK WIGHTMAN.

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