US1231894A

US1231894A - Method of regulating the temperature of superheated steam.

Info

Publication number: US1231894A
Application number: US33515A
Authority: US
Inventors: David S Jacobus
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1909-05-24
Filing date: 1915-06-11
Publication date: 1917-07-03
Anticipated expiration: 1934-07-03

Description

.D. S. JACOBUS.

METHOD OF REGULATING THE TEMPERATURE OF SUPERHEATED STEAM.

APPLICATION FILED JUNE H. 1915.

LQSLMD Patented; July 1917.

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APPLICAHON FILED JUNE H, 1915.

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Patented July 3, 1917.

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DAVID S. JACOIBUS, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO THE BABCOCK 8a WILGOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD OF REGULATING THE TEMPERATURE OF SUPERHEATED STEAM.

Original application filed May 24:, 1909,

To all whom it may concern:

Be it known that I, DAVID S. JAcoBUs, a citizen of the United States, residing at Jersey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Methods of Regulating the Temperature of Superheated Steam, of which the following is a specification.

The object of my invention is to establish and maintain either a practically constant temperature in superheated steam, where so desired, or a temperature which may be made to vary to meet certain conditions of service. This object of reducing the amount of fluctuation in the temperature of superheated steam to a degree which will prevent any danger from an excess of superheat, is accomplished by first bringing the temperature of the steam to a substantial constant, and then causing the steam, after its temperature has been modified, to act upon a thermostat which latter may be in the form of a closed vessel, which I have termed an evaporator, containing air or other gas or a volatile liquid, or which may be one depending upon the unequal expansion of different metals and utilizing the pressure generated in the evaporator by the heat of the superheated steam, or the expansion or contraction of the metals, to control the temperature of the steam.

The resent application is a division of my app ication Serial No. 498,012, filed May 24, 1909, (Patent No. 1,149,265, dated August 10, 1915), and is designed to cover the method and apparatus involving the broad invention of the parent case, but wherein the temperature change of the superheated steam to produce a substantially constant temperature is efiected without contact of the temperature-changing medium by indirect conduction as, for example, through a pipeor conducting surface.

The invention will be understood by reference to the accompanying drawings in which Figure 1 is an elevation, partly in section, of a portion of a steam boiler plant containing apparatus for practising my invention; Fig. 2, a similar view showing a modified form or apparatus; and Fig. 3 an enlarged view of the thermostat, partly in Specification of Letters Patent.

Patented July 3, 1917..

Serial No. 498,012. Divided and this application filed June 11, 1915. Serial No. 33,515.

section. Similar reference. numerals indicate similar parts in the several views.

Referring to the form of Figs. 1 and 3 the numeral 1 designates a portion of the tubes of a water tube boiler; 2 a steam and water drum and 3 a super-heater. Leading from the outlet'header 3' of the superheater is a pipe 4 through which the steam flows to the main steam pipe 5. In an enlarged section of the latter is placed an attemperator of any desired character by which the temperature interchange may be efiected so long as the interchange is carried out without di rect contact of the fluid. In the form shown this consists of a coiled pipe 6. through which pipe a cooling medium is caused to flow. In the inlet 7 of the pipe 6 is a valve 8 which, upon starting the apparatus, is opened to admit suliicient of the cooling medium to reduce the degree of superheat to the predetermined constant, and this constant is substantially maintained by the following means. In another section of the main 5, beyond the coiled pipe or attemperator 6, is a thermostat 9. In the form tube spirally twisted which gives the desired surface, and at the same time spreads out the contained liquid or causes it to contact with a large surface which aids or facilitates its evaporation and renders such liquid extremely sensitive to variations in the temperature of the surrounding steam. The evaporator is closed at its upper end by a plug 10 adapted to receive one end of a pipe 11. The latter passes through a stufling box seated in a bushing 12, and leads to a regulator or governor of the Carmichael or Spencer type, the essential features of which are shown in the drawings, and the operation of which is well understood. It comprises a chamber 13 having a flexible dia phragm therein which receives on its under side, from pipe 11, the pressure generated in the evaporator.

Secured to the diaphragm is a stem 14 which bears against a lever 15 having its fulcrum at 16. To the outer end of lever 15 is connected an auxiliary lever 17 which has a connecting rod to a pilot valve in the cylinder 18. The force acting upon the under side of the diaphragm in chamber 13 is opposed by the weights on the levers 15 and 17. By means of this sys tem of levers and weights the pilot valve is made to operate a piston in the cylinder 18. hen the pressure generated in the evaporator increases, the levers 15 and 17 are raised, thus admitting water from a high pressure reservoir 19 to the under side of the piston, and when the vapor pressure decreases, the water from said reservoir is admitted tothe upper side of the piston. To

the piston is connected a power lever 20, the free end of which is connected, through a turn-buckle 21, to a lever 22, attached to the valve 8 in pipe 7. \Vhen starting the apparatus the turnbuckle 21 is adjusted so that the valve 8 will be fully opened when the lever 22 is in its uppermost working position, and closed when it is in its lowermost working position. After this the turn-buckle does not require further adjustment. Also the weights on the levers 15 and 17 are so adjusted that the pressure produced by the evaporation of the volatile liquid in the evaporator 9, for the given constant temperature of superheat required, will act on the diaphragm in chamber 13, and through the described system of levers maintain the valve 8 in a position which will admit the proper volume of the cooling medium to maintain the temperature of the steam substantially at the required constant. After this the apparatus will automatically maintain the temperature at a substantial constant, and in so doing the apparatus is governed by any slight change in the temperature of the steam leaving the attemperator. The forces operating the pilot valve are those corresponding to the slight difierences in pressure which are produced in the evaporator by the slight temperature variations in the steam surrounding the evaporator, and it is essential that the movements of the pilot valve be as free as possible.

The piston which is operated by the water pressure provides the amount of force for moving the power lever 20 which is limited only by'the size of the piston and the water pressure in reservoir 19, so that the pilot valve which is operated by a comparatively minute force may call into play any amount of force required to operate the power lever. It is necessary that the power and range of motion shall be such that the lever 22 may either completely close the valve 8 or open it the required amount. The action of the apparatus as a whole is to cause the vapor pressure in the evaporator 9 to act through the regulator in such manner that when there is any excess in the outgoing steam temperature the variation of the pressure will cause the power lever 20 to rise andactuate the valve 8 to admit an mlditional volume of the cooling medium to the attemperator coil 6, and thus reduce the temperature of the steam passing through the attemperator to the predetermined normal or constant de gree. On the other hand, should the temperature of the outgoing steam fall below the normal or constant degree, the pressure of the vapor in the evaporator 9 will fall below the set figure and the apparatus will reduce the volume of the cooling medium admitted to the attemperator through pipe 7, and thus prevent any lowering of the steam temperature below that at which the apparatus is set.

If, instead of reducing the temperature of the superheated steam to the lowest degree furnished by the superheater, or a still lower amount, it is desired to limit the highest temperature that the steam shall attain on reaching the engine, it may be done by a proper adjustment of the weights on the regulator levers 15 and 17. Also, instead of admitting water into pipe 6 I may usesaturated steam to effect the desired reduction in temperature, the volume being controlled by operating the valve 8. Also, instead of employing water as a supplemental source of energy to operate the piston in cylinder 18 to move the power lever 20, steam, air or any other fluid may be used.

Instead. of admitting water or saturated steam to the pipe 6, I may use oil heated to a temperature above that of the superheated steam, the object in such case being to raise the temperature of the steam when it falls below a predetermined degree of superheat. To eifect this the adjustment of valve 8. will be made to correspond with a variation of steam temperature to admit a suflicient volume of oil to pipe 6 to raise the steam temperature to the degree desired, whether that be the highest degree of superheat as the steam leaves the superheater 3, or any degree between the limits of variation which may be determined upon as the desired constant.

In Fig. 2 I have shown a modification in the construction of the attemperator. In addition to the coil 6, through which a cooling medium is caused to flow, I introduce a second coil 23 connected to a pipe 24; through which oil or some other medium heated to a temperature above that of the superheated steam, or above any constant which it is desired to maintain, is conveyed. In the pipe 24 is a valve 25. The parallel levers 22 and 26, connected respectively to the valves 8 and 25, are connected together by rods 27, one of which rods is connected to the power lever 20. The valves 8 and 25 are so adjusted that the movement of lever 20 will effect the opening of one as the other closes. By this means, if the predetermined constant is within the limits of initial-variation of the'steam temperature, the valve 8 will be opened to admit water to the coil 6 to reduce the temperature to substantially that of the constant, and valve 25 will be opened to admit heated oil to coil 23 to raise the temperature when it falls below the constant. The movement of lever is effected, by the same means before described, through variations of pressure generated in the evaporator 9 by any variation of the steam temperature surrounding the evaporator. By adjusting the weights on the levers 15 and 17, the initial adjustment of the valves 8 and is elfected, this adjustment being varied only as the steam temperature surrounding the evaporator varies.

What I claim and desire to secure by Letters Patent of the United States is 1. The method of regulating the temperature of superheated steam which consists in subjecting the steam to the indirect action of a cooling medium through con-' duction to reduce the temperature of the steam to a predetermined constant, and then causing any variation from that constant to effect a corresponding variation in the volume of the cooling medium to thereby restore the steam temperature to substantially that of the constant.

2. The method of regulating the temperature of superheated steam which consists in subjecting the steam to the indirect action of a cooling medium through conduction to reduce the temperature of the steam to a predetermined constant, then passing the steam into contact with a thermostat and utilizing any variation from that constant to vary the amount of the cooling medium to restore the steam temperature to substantially that of the constant.

3 The method of regulating the temperature of superheated steam which consists in subjecting the steam to the indirect action of a temperature-changing medium through conduction to bring the temperature to a predetermined constant, and then causing any variation from that constant to act upon and control a source of supplemental energy to effect a. corresponding variation in the volume of said medium to thereby restore the steam temperature to substantially that of the constant.

4. The method of regulating the temperature of superheated steam which consists in indirectly subjecting the steam to a tem perature-changing medium through conduction to bring the temperature to a predetermined constant, then passing the steam after its temperature has been reduced into con- DAVID S. JACOBUS.

Witnesses EDITH CAMP, E. J. HAYES.