US2032391A - Regulation of steam temperature - Google Patents

Description

March 3, 1936.

w. H, ARMACOST 2,032,391

REGULATION OF STEAM TEMPERATURE Filed May 26, 1953 T0 PRIME Movsk INVENTOR Wilbur H. Armacost.

BY /7au;

ATTORNEY Patented Mar. 3, 1936 UNITED STATES PATENT OFFICE Wilbur H. Armacost, New York, N. Y., assignor to The superheater Company, New York, N. Y.

Application May 26, 1933, Serial No. 622,969

2 Claims.

My invention relates to regulation of steam temperature.

Experience in the operation of steam prime movers has shown the desirability of utilizing steam at as high a temperature as possible. However, the construction of each prime mover sets a limit on the temperature of steam which can be supplied to it and beyond which the prime mover is damaged as the temperature of the steam is increased. Various means have been proposed for regulating the temperature of the steam some of which have met with considerable success, but none of which are equally well adapted to all installations and it is an object of my invention to provide a method and arrangement for supplying high temperature steam which shall produce a close regulation of temperature and which shall have a wide range of application.

In order that my invention may be fully and readily understood, I will now describe in detail and in connection with the accompanying drawing a boiler plant for supplying superheated steam, such plant adapted to operate in accordance with my novel method and selected by way of example from a number of possible embodiments of my invention. In the drawing,

The figure is a sectional elevation, partly diagrammatic in character, of a boiler plant in accordance with my invention.

The plant illustrated in the drawing includes a plurality of generating units I0, I0 of known type, each having an integral superheater [2, I2 and each connected to deliver superheated steam through one of the discharge pipes l4, l4 to a superheated steam main I6 common to all the boilers of a given battery. Preferably, the superheaters 12 have a rising temperature load characteristic, this being the ordinary thing, the steam temperature increasing with the load. The design and proportions of the boiler are such that the steam delivered from the superheaters 42 of the generating units l0, altho superheated, is not at as high a temperature as desired for final use in the prime mover. Moreover, its temperature ordinarily varies with the load. In accordance with my invention, I raise the temperature of the steam delivered by the superheaters l 2 a varying amount depending on the load on boilers I0, and therefore on the temperature of the steam from superheaters l2, to make the final steam temperature substantially that desired for use in the prime mover and to maintain such temperature substantially constant. For these purposes, the steam from main [6 delivers through the normally open valve I8 to a conduit 20 which delivers in turn to a header 22. Header 22 serves as the inlet header for a superheater 24 having an outlet header 26 which delivers into a conduit 28 from which steam flows through normally open valve 33 into the main 32 for delivery to the prime mover. It will be seen that superheater 24 receives the steam from an entire battery of superheater boilers Ill. Superheater 24 is heated by gases from furnace 34 which forms, preferably, part of a skeleton generator 36 having a bank 10 of generating tubes 38, 38 between superheater 24 and furnace 34. Bank 38 tempers the heat of the gases from furnace 34 somewhat but not so much but what superheater 24 may readily add to the temperature of the steam received there- 15 by to raise it to the final temperature desired. When the temperature of steam delivered from primary superheaters l2 tends to rise with the load, the total of the heat units needed to be supplied by the superheater 24 does not vary a great 20 deal with the load and the furnace 34 can be operated nearly at a constant rate; My method of adding the final superheat to the steam from a battery of superheat-er boilers by means of a separate superheater is therefore particularly 25 well adapted to the average boiler plant having integral superheaters since the great majority of present plants have a rising temperature load curve.

The steam generated in bank 38 is, however, 30 only at the temperature corresponding to its pressure and I take advantage of this fact to increase the efficiency of the boiler 36 by passing the steam from such boiler through a superheater 40 which lies in the path of gases from furnace 5 34 at a point immediately following superheater 24 in such path. The temperature of the furnace gases is thereby lowered while the temperature of the steam from boiler 36 is raised approximately to that coming from superheaters l2 of boilers 40 I0. It is convenient to mix the steam from superheated 40 with that from superheaters I2 in the inlet header 22 for superheater 24 and I have illustrated the units of superheater 40 as connected directly to header 22. To further reduce the 4:; temperature of the gases from furnace 34, I prefer to place some additional heat absorbing means in the path of such gases at a point following the superheater 40. I have illustrated for this purpose a means comp-rising an economizer 42, but 50 do not limit myself to this.

In the arrangement illustrated, a by-pass having a valve 44 therein, is placed between the main l6 and the main 32. Such by-pass, however, will usually be closed. 55

The method of operation of the plant illustrated and disclosed herein will be clear from the foregoing description and will not be recapitulated.

It will be understood also that, while I have disclosed a specific arrangement, I do not limit myself in all cases to the details of such disclosure.

What I claim is:

1. The combination of a bank of boilers each provided with a superheater in which the steam generated is superheated to a point approximating but somewhat below the desired final superheated steam temperature; a superheater generating unit having a gas path therethrough; steam generating means in said'path; a. superheater following said generating means in saidpath; a second superheater in said gas path and connected to receive the steam from said generating means, said second superheater being positioned beyond said first superheater in said gas path so that the steamfrom said generating means issuperheated to a point approximating but somewhat below the final desired superheated steam temperature; and connections for passing the steam from said second superheater together with the steam partially superheated in the superheaters of said boilers to said first mentioned superheater for raising the temperature of steam passed therethrough to the desired final superheated steam temperature.

2. The method of regulating the final temperature of superheated steam from a bank of boilers provided with superheaters having a rising temperature characteristic which comprises generating steam in said boilers, passing said steam through the superheaters associated therewith and heating it therein to a point approximating but somewhat below the final desired temperature, passing said partially superheated steam through the heat absorbing elements of a superheater fired separately from said boiler superheaters for adding relatively small amounts of heat to-said partially superheated steam, and controlling the firing rate of said separately fired superheater to vary the additional amount of superheat imparted to said partially superheated steam for attaining the desired final superheated steam temperature and maintaining the latter substantially constant.

WILBUR' H. ARMACOST.

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