US1724996A - Boiler-control system - Google Patents

Description

Patented Aug. 20,

UNITED STATES- PATENT oEElcE.

WARREN DOIBLE, OF'SAN IRANCISCO, CALIFORNIA, ASSIGNOR TO DOBLE LABORA- TORILES, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

BOILER-CONTROL SYSTEM.

Original application filed December 13, 1919, Serial No. 344,741. Divided and this application filed November 20, 1923.

, This invention relates to a system for controlling the temperature and pressure conditions in a steam boiler, and more particularly to such a system in which the water or other heat absorbing medium is supplied to the boiler automatically in accordance with prescribed conditions oftemperature and pressure.

This application is a division of an application filed Dec. 13, 1919 in my name,

entitled Steam power plant control and having Serial No. 344,741, now Patent No. 1,481,460. 1

,It is one of the objects of my invention to prevent undue temperature or pressure rise in a boiler by properly controlling the intake of the feed water. This is of especial importance in boilers that are adapted to operate the engines for propelling automo- 2 biles, since the conditions imposed upon such engines are not only exceptionally severe, but also vary rapidly.

It is another object of my invention to provide an electromagnetically controlled source of liquid supply, in which the electric circuits are operated in response to a combination of pressure and temperature conditions in the boiler;

My invention possesses other advantageous features, some of which with the foregoing, will be set forth at length in the following description, where I shall outline in full that form of the invention which I have selected for illustration in the drawing accompany- 85 ing and forming part of the present specification. Although I have shown in the drawing but one embodiment of my invention, I do not desire to be limited thereto, since the invention as expressed in the claims may be embodied in other forms also.

Referring to the drawing:

The single figure is a diagrammatic representation of an installation embodying my invention.

In the present instance the boiler 1 is heated by the combustion of liquid fuel, such as kerosene, distillate, or oil. In order to vaporize the fuel so that it may serve most efficiently as a heat producing medium, it is conducted to arotating cup 2 through a pipe or conduit 3, leading from a small tank 4 which in turn connects to a source of supply by the aid of a pipe 5. The cup 2 is Serial No. 75,850.

.inent for supplying it with the liquid to e heated therein. An appropriate form of such a device is diagrammatically illustrated, and comprises a reciprocating pump 10, its discharge being connected as by pipe llto the boiler, and, arranged to be driven by the crank and rod device 12. This device is coupled to the engine operated from the boiler, so that the operative parts of pump 10 are continuously in motion during the operation of the engine. The intake to the pump is controlled by) a valve 13 in a chamber 14 connected as y pipe 15 to a source of liquid. The valve is so arranged that it seats whenever the pump 10 is on .its dischargestroke, but unseats in. response to the reduction .in pressure above it, when the pump is on its suction stroke. This type of pump as thus described, may readily be rendered inactive, irrespective of the movement of the parts 12, by moving and retaining the valve 13 in its unseated position. By holding the inlet valve unseated, the pump is rendered inoperative to introduce water into the boiler. A check valve 60 in the pipe 11, betweenthe boiler and the pump re vents discharge of water from the boiler. One method by which the inlet valve is retained in its unseated position, in response to definite temperature and pressure conditions Within boiler 1, will be described hereinafter in detail.

The pressure and temperature controLdevices are also used to affect the operation of the liquid fuelburner. The pressure controllin device, which is merely diagramniatica ly illustrated, includes a mechanically movable lever 16, the position of which is dependent upon the pressure existing in .the boiler 1. This may be accomplished for example by the'aid of a cylinder 17 which is connected to the boiler 1, and which has a piston 18 mechanically attached to the lever 16. An increase in pressure causes lever 16 to rock in a clockwise directionagainst gravity or a spring 16*. The lever is so arranged that its movement regulates the flow of fuel to the cup 2, as by aid of a valve 19 and a connection 20. Inorder to ensure complete combustion at all times, and that no excess air is supplied to absorb heat wastefully, another mechanical connection 21 may be provided to a butterfly valve 53 which controls the amount of air that can be supplied to the combustion chamber through passageway 7, air is discharged by the blower 9 through the passage 7 into the combustion chamber, 'the air flowing to the blower through the opening 22 and past the rotating cup 2. The simultaneous, continuous control of the fuel intake and the air intake en-- due to variations in temperature. The move ment ofthe outer end of the rod is caused. to operate electrical contacts, such as 25 and 26, which cooperate with stationary, spring pressed contacts 27 and 28. The- contacts 25 and 26 are arranged on a disk 29 carried byv the end of the rod. The temperature control is such that an excessive or dangerous rise .in temperature is prevented. The con tacts 26 and 28 serve to control the fuel feed, the supply of air and the circuit of the blower motor, and are so adjusted that they effect this controllin only upon the existence of undesirable fiigh temperatures.

The arrangement by which this result is accomplished may take the form of an electromagnetically operated valve 30 in the fuel tank 4. This valve is arranged to'be urged, as by gravity, to its seated position, whereb it closes the fuel supply pipe 3,but it is held; during normal operation, awa from its seat by the aid of a solenoid 31. he energizing circuit for this solenoid may be traced as follows: from a common ground return 32, to a source of electrical energy 33, a manually operable switch 34, connection 35, a pair of normally closed contacts 36 (which open only in response to excessive pressure conditions, operating on arm 16 mechanically controlling these contacts), connection 37, contacts 26 and 28, connection 38, solenoid 31, and ground 39. By this arrangement the flow of fuel will be interrupted by valve 30 When- I is opened at these contacts. Theenergizing i circuit for motor 8 may be traced as follows: from ground 32, to source of electricity 33, switch, 34, connection 42, contacts 41 and 40, motor 8, back to ground at 43.

The control of the feedwater pump 10 'will'now be described. Normally the valve 13 is permitted tofollow the reciprocations of this pump, to seat and unseat on the discharge and suction stroke respectively. A solenoid 44 is arranged to be energized to hold the valve unseated and thus render the pump 10 inactive. This occurs whenever the pressure in the boiler rises, to an objectionably high value, and is accomplished by the aid of a stationary contact 45 and a contact 46 movable in accordance.- with the movement of lever arm 16. When this arm moves a substantial distance in response to a predetermined increase in pressure in boiler -1, the contacts 45, 46 close, and the solenoid 44 is energized, unseating the valve 13 and disabling the pump until the pressure is reduced to a normal value. The energizing circuit for the solenoid 44 may be traced as follows: from-ground 32, to source of electricity 33, switch 34, connection 47, contacts 46-and 45, connection 48, connection 49, solenoid 44, and ground 50. It is to be noted at this point that the contacts 45 and 46 are operated whenthe excessive pressure in the boiler is caused for example by the introduction of water by the feed pump, as when the automobile upon which the boiler is installed is traveling down a long grade, and the engine is turning over, operating the ump 10.

eans are also provided for controlling the introduction of feed water into the boilerby temperature conditions within the boiler, to prevent flooding of the boiler when the temperature therein is low. This is accomplished by rendering the pump 10 inoperative to pump water when the boiler temperature is below the predetermined minimum. Connected to the solenoid 44,

.which controls the valve 13 of the pump, is

a temperature controlled circuit 515249 which is connected in parallel with the pressure control circuit. The contacts 25 and 27, the relative positions of which are controlled by boiler temperature conditions, are arranged in the circuit 5152-49. When the temperature of the boiler falls below the for supplying predetermined minimum, the contacts 25 and 27 are brought into engagement, closing the circuit through the solenoid 44, raising the valve 13 from its seat and rendering the" pump inactive. When the temperature subsequently rises above the predetermined minimum, the contacts 25 and 27 are separated, the solenoid 44 is de-energized and the pump functions to introduce water into the boiler. d

The operation of the system is as fol-, lows: to set the boiler into operation, it is necessary to close the switch 34, either manually or in any other way. The valve 30 will then be opened, to permit fuel to feed to the cup 2, the control circuit for this valve being closed at contacts 36, and 26 28. The opening of valve 30 causes contacts 40 and 41 to close, and the motor 8 is energized thereby. Fuel is then vaporized by cup 2 and is projected into the combustion chanber by the fan 9 where it is ignited by any suitable device. The boiler 1 is now in full operation. By aid of valve 19, the pressure is maintained within the desirable predetermined limits. However, in case this pressure for any reason becomes too high, .the circuit for electromagnet 31 is abruptly interrupted at contacts 36 and the burner becomes inoperative. At the same time pump 10 is inactive due to engagement of contacts 45 and 46. Upon a return to normal pressure, the flow of fuel and operation of motor 8 is automatically resumed. Excessive temperatures will also disable the burner apparatus, by aid of rod 23 and contacts 26-28. Regulation of boiler temperature is also effected by the aid of contacts 25-27, and solenoid 44, as has been already described. The pump 10 cannot function unless the temperature is above a definite lower limit imposed by these contacts, and unless the pressure is below a definite higher limit imposed b contacts 45 and 46. It is thus seen that t eactuation of puinp 10 isaccomplished only when the system de mands it. a

I claim:

1. In combination, a liquid heater, continously operating means for supplying liquid to said heater, an electrical translating device arranged, in response to variations in its energization, to control the liquid supply, and means responsive to both pressure andtemperature variations in the heater for varying the energization of said device.

2. In combination, a liquid heater, continuously operating means for supplying liquid to said heater, a'solenoid for controlling the flow of liquid to the heater, and means responsive to both pressure and temperature variations in the heater for controlling the solenoid.

3. In combination, a liquid heater, means liquid to the heater, an electrical translating device, arranged, in response to variations in its energization, to control the liquid supply, means responsive to temperature below a set limit within the heater for actuating the translatin device to interrupt the liquid supply, an means responsive to pressure within the heater above a set limit for actuating the device to interrupt the liquid supply.

4. In combination, a liquidheater, means for supplying liquid to said heater, a solenoid for controlling the flow of liquid to the heater, an electric energizing circuit for the solenoid, means responsive to temperature within the heater below a set limit for affecting this circuit in such a way that the solenoid interrupts the liquid supply, another electric circuit for the solenoid, and means responsive to pressure within the heater above a set limit for controlling this latter circuit to cause the solenoid to interrupt the liquid supply.

5. In combination, a liquid heater, means for supplying liquid to the heater, a solenoid for controlling the flow of liquid to the heater, a pair of circuits in parallel for independently energizing said solenoid, means respon sive to pressureconditions within the heater for controlling one of the circuits, and means responsive to temperature conditions within the heater for controlling the other circuit.

6. In combination, a liquid heater, a reciprocating pump for supplying liquid to the heater, an intake valve for the pump ar-" ranged to be alternately opened and closed on the intake and discharge strokes respectively, and means for maintaining the valve open in response to temperature and pressure conditions within the heater.

7. In combination, a liquid heater, a reciprocating pump for supplying liquid to the heater, an intake valve for the pump are ranged to be alternately opened and closed on the intake and discharge strokes respectivly, means for maintainingv the valve open in response to a temperature'in the heater below a set limit, and means for maintaining the valve open in response to a pressure in the heater above a set limit.

8. In combination, a liquid heater, a reciprocating pumpfor supplying liquid to the heater, an intake valve for the pump arranged to be alternately opened and closed on the intake and discha e strokes respectively, a solenoid arranggd when energized to maintain the valve open, means for energizing the solenoid in response to a temperature in the heaterbelow a set limit, and another means for energizingthe solenoid in response to a pressure in the heater above a set limit.

9. The combination with a heat absorbing medium containing device, of a pump for forcing water into said device, a valve for controlling the flow of water into the device, a solenoid for operatin said valve, the energizing of the solenoi serving to stop the flow of water into the device, means operative by an increase in pressure in the device to a predetermined pressure for energizing the solenoid and means operative by an increase in temperature in the device to a predetermined temperature for deenergizing the solenoid.

10. In combination, a fluid heater, 8. pump having a valve, electro-magnetic-means for making-the valve inoperative, thereb makuid to ing the pump ineffectual to pump the heater, the electro-magnetic means being controlled by variations in temperature and pressure in the fluid heater.

30 whereof, I have hereunto set WARREN DOBLE.

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