US1190167A - Automatic control for flash-boilers. - Google Patents

Description

, L G. H. HILL. 5 AUTOMATIC CONTROL FOR FLASH BOILERS. APPLICATION mm MAY 25, 1915.

;' 1 ,1 90, 1 6'? I l atentm July 4, 1916.

2 SHEETS-SHEET 1.

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\ Inventor: (Beer 6 H. Hill,

e. H. HILL.

AUTOMATIC CONTROL FOR FLASH BOILERS.

APPLICATION FILED MAY 25, 1915.

1;190,167. Pdtentedluly l, 1916.

ZSHEETS-SHEET 2.

lnVntor: George H. NM,

His Attorney UNITED STATES PATENT 1 OFFICE.

QEORGE H. HILL, SCHEHECTADY, NEW YORK, ASSIGNOB TO GENEBALELECTBIG COMPANY, A CORPORATION OFN'EW YORK.

nu'ronn'rrc con'rnon FOR rmsn-no nnns.

Specification of Letters Patent.

Patented July 4, 1916.

To all whom it may concern:

Be it known that I, Gnoncn H. HJLL, a

' citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Automatic Control for Flash-Boilers, of which the following is a specification. v

My invention relates to electric water heaters and hasfor its object the provision of means whereby the temperature and flow of water in such devices may be controlled in a reliable and eflicient manner.

My invention relates more specifically to water heaters for generating steam, and more particularly to water heaters of the type known as flash boilers in which steam is generated rapidly. In a flash boiler, wa-

ter is forced through passages such as pipe sections which are heated to a relatively high temperature so that steam will be generated almost instantly when the water touches the heated surfaces. When electric energy is used for heating the water by passing the electric current through the pipe, it is necessary that the pipe be of a considerable length in order to obtain sufficient electrical resistance. A high pressure is therefore required to force the water through the pipe, and to overcome this difiiculty, it has heretofore been proposed to divide the pipe into sections connected in parallel with reference to the Water supply so that the water may be pumped through each section independently of the others, each section having its own inlet and discharge connections. Such a heating system is disclosed in a patent to Batchelder No. 1,019,413 which was issued March 5, 1912.

One of the difiiculties encountered in such a system is that the delivery of water to the various sections is not always uniform. This is due to mechanical difierences in the various pumps, to the presence of air in the water, or to various other causes. The result becomes cumulative and asection is liable to be burned out.

In a ccordance with my invention, provi- S1011 is made for counteracting the tendency of any of the sections toward becoming overtrolling the by-pass in 1; Fig. 3 is a diagrammatic view similar to Fig. 1, showing a modification of, my invention; Fig. 4: is a sectional view of the valve controlling the by-pass of Fig. 3 Fig. 5 illustrates still another modification, and Fig. 6 is a sectional view showing a valve applicable to the system there illustrated. I

Referring, now, to the drawings, and first to Fig. 1, A is a flash boiler composed of a plurality of pipe sections 10, 11, 12, and 13, which are insulated from each other at 14:, and are provided with inlets 15, insulated from the pumps at 16. Separate outlet pipes 17 are also provided, which communicate with a delivery pipe 18 by means of a pipe 19 which is insulated from the outlet pipes 17 as indicated. A tank 20 constitutes the source of water supply from which water is fed to the various pipe sections by means of pumps 21, 22, 23, and 21. The pumps are operated through suitable gearing 27 by a motor 25 connected to the line 26.

The system thus far described is the same as that disclosed in the Batchelder patent above referred to, and no novelty is claimed therefor.

In order to overcome the difiiculties which have heretofore been experienced as above outhned, I provide relays 28, 29, 30 and 31, one for each heater section. These relays are made responsive to the temperature of the various sections of the heater by providing each relay with a coil connected across a heater section so that the'rise in temperature of the section will, by increasing the voltage drop across the section, cause the relay to operate. In order that the relays shall not be affected by variations in voltage, I also provide each of them with a coil connected to the main source of potential and which is differentially wound with respect to the other. As illustrated, therefore, relays 28, 29, 30 and 31 each comprises two windings, the lower winding being a potential winding connected across the line while each upper .winding is connected across a heater section. The potential wind-- ings are all in series and the arrangement of each relay is such that under normal conditions, the relays will .be inoperative due to the differential action of the two windings. Each of these relays controls a valve which in turn controls the supply of water to a heater section. In the particular arrangement shown, in Figs. 1 and 2 the relays control coils 36 which, when energized, open a normally closed valve 37 in a by-pass around the pump which feeds the section controlled by this particular relay.

The operation of this form of my inven tion is as follows: Normally the motor will be operating continuously, driving the pumps 21, 22, 23 and 24. The by-passes around these the heater sections are being fed alike. The relays 28, 29, and 31 are deenergized so that their switch arms are in engagement.

with the lower contacts which are connected with the various valve coils 36. If now, one of the pipe sections should become overheated, due to any cause, the voltage drop across that part of the section is increased causing the relay'eontrolled by this section to operate. Assuming for example, that the section 10 becomes overheated: the relay 28 will be operatively energized since the ampere turns of the upper winding will be increased, while the lower winding will be unaffected. The operation of relay 28, causes the switch arm 32 to engage its upper contact thereby completing the circuit from the line through switch arm 32 and thence in parallel through the switch arms 33, 34 and 35 which are in a lower position, to the three coils 36 controllin of the umps 22, 23 and 24, de iverin water to t e sections 11, 12, and 13 respectlvely; The by-passes around the umps 22, 23 and 24 are now opened, there y causing these pumps to decrease the amount of water de-' livered by them to the sections 11, 12, and 13.

and thereby raising the temperature of these sections. This causes the resistance and hence the voltage of these sections to be increased and this in turn decreases the voltage drop across the section 10. The temperature-of all of the sections is thereby equalized. It will be noted that with the differential arrangement of the relays any variation in line voltage will affect the two coils of the relays equally so that the. relays pumps are closed and all of the valves f will not be affected by any variation of line voltage, but will only be affected by the va-. riations in the potential drop across the various heater sections which in turn will be governed by the temperature.

In Fig. 3, I have shown a modified form of the invention in which the desired result is produced by increasing the flow of water to the overheated section instead of decreasing the flow of water to the other sections. The arrangement of heater sections and relays is the same as that of Fig. 1, butinthis case, the by-pass around each pump is normally open so that under ordinary con ditions, a certain amount of water is being by-passed around each pump. When, therefore, a section becomes overheated, the relayassociated with this particular section operates in the manner described in connection with Fig. 1. In this case, however, only one winding 36 is energized to close a valve 37*. For instance if the section 10 should become overheated, the relay 28- would operate to energize the coil 36 controlling the valve 37 in the by-pass around the pump 21. This will cause the rate of delivery of water to section 10 to be increased. I

In Fig. 5, I have illustrated another modification in which the water is delivered to the heater sections from a tank 20 in whichthe pressure is maintained constant. The tank is supplied from a pump 39 and an air dome 40 is provided for maintaining a predetermined pressure higher than needed to normally supply the boiler. In this case the valves 37 B are located in the pipes leading from the tank to the various heater sections. The valves are normally closed b' springs 41 and open at-a predetermined di ference in pressure between the tank and b01ler section to permit water to pass from the tank to the various sections The coils 36, one of which is energized by the operation of each of the relays, act upon the valves in opposition to thespring 41. In the event of overheating of a section, the valvecontrolling the flow to that section W111. be opened by reason of the coil acting against the spring 41, thus allowing the full pressure of the tank into the section and thereby increasing the rate of delivery of water to the overheated section.

In accordance with the provisions of the patent statutes, I have described the principle-of operation of my invention, together with the apparatus which I now considerto represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is onl illustrative, and that the invention can be carried out. by other means. J 3

What I claim as new, and desire to secure by Letters Patent of the United States, 1s: 1

1. An electric heaitingsysten comprising a plurality of pipe sections in which the water is electrically heated, a source of water supply feeding said sections in parallel,

and means for equalizing the temperatures of all of the sections.

2. An electric heating system comprising a plurality of pipe sections in which water is electrically heated, a source of water supply for feeding said sections in parallel, and electrically controlled means for varying the relative flow of water to these sections to equalize the temperature of said sections.

3. An electric heating system comprising a plurality of pipe sections in which the water is electrically heated, a source of water supply feeding said sections in parallel, and means controlled by the temperature of a section for controlling the relative flow of water to the various sections.

4. An electric heating system comprising a plurality of pipe sections, a source of water supply feeding said sections in parallel, means for passing an electric current through said sections in series, and means controlled by the temperature of any one section for controlling the relative flow of Water to the various sections.

5. An electric heating system comprising a plurality of pipe sectlons, electric heating means associated therewith, a source of water supply feeding said sections in parallel, and electromagnetic means controlled by the temperature of a section for controlling the flow of water to the various sections.

6. An electric heating system comprising a plurality of pipe sections in which the water is electrically heated, a source of water supply feeding said sections in parallel, and means comprising electromagnetic relays provided with coils connected across the respective pipe sections for equalizing the temperatures of all of the sections.

7. An electric heating system comprising a plurality of pipe sections in which water is electrically heated, a source of water supply for feeding said sections in parallel,

electromagnetic relays controlled by the temperature of these sections, and valves controlled by said relays for controlling the water flow to the various sections.

8. An electric heating system comprising a plurality of pipe sections in which the water is electrically heated, each having a separate inlet, a separate pumping device connected with each inlet, by-passes around the various pumps, and means controlled by the temperatures of the various sections for actuating said by-passes to vary the amount of liquid delivered to the various sections.

9. An electric heating system comprising a plurality of pipe sections in which water is heated by the passage of current therethrough, a source of water supply feeding said sections in parallel, and electromagnetic means jointly under the control of the supply voltage and the voltage across the various sections for equalizing the temperatures in all of the sections.

10. An electric heating system comprising a plurality of pipe sections in which water is heated by the passage of current therethrough, a source of water supply feeding said sections in parallel, and means comprising differential relays whose coils are jointly controlled by the supply voltage and the voltage across the various pipe sections, respectively, for equalizing the temperatures in all of the sections.

11. An electric heating system comprising a plurality of pipe sections, a source of water supply feeding said sections in parallel, means for passing an electric current through said sections in series, and means jointly under the control of the line voltage and the voltages across the various sections for controlling the relative delivery of Water to the various sections, and thereby controlling their temperatures.

, 12. An electric heating system comprising a plurality of pipe sections in which Water is heated by the passage of current through the sections in series, a source of water supply feeding said sections in parallel, electromagnetic relays energized diiferentially by the supply voltage and the voltage across the pipe sections and valves controlled by said relays for controlling the How of Water from the sourceto the various sections.

In witness whereof, I have hereunto set my hand this 24th day of May, 1915.

GEORGE H. HILL.

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