US1983422A - Desuperheater - Google Patents

Description

Patented Dec. 4, 1934 PATENT OFFICE DESUPERHEATER Vanderveer Voorhees, Hammond, Ind., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana Application January 15, 1932, Serial No. 586,917

8 Claims.

This invention relates to improvements in the art and apparatus for desuperheating steam and it particularly pertains to the direct or contact type of desuperheater.

In the art of generating steam and producing power, the tendency has been to go to higher pressures and greater degrees of superheat. It is now customary to produce superheated steam at about 400 pounds pressure and at a temprature of 600- 700 F. When, however, it is desired to use steam for heating purposes, distillation operations and the like, it is uneconomical to use superheated steam of a high degree of superheat. For example, it highly superheated-steam is fed into a large distributing system, the heat loss will be aggravated because of the high temperature. Heretofore superheated steam has commonly been desuperheated by spraying water into said steam, but where ordinary hard water only is available 20 the dissolved solids in the water are deposited on the lines and valves, soon rendering them inoperative.

The object of my invention, therefore, is to provide a desuperheater whereby steam with a high degree of superheat may be desuperheated entirely or partially and distributed for distillation, heating, and similar purposes.

Another object of my invention is to provide an adjustable desuperheater so that any desired degree of superheat may be removed from the superheated steam.

A further object is to provide a desuperheater that will automatically adjust itself to produce a variable supply of steam with a predetermined degree of superheat.

Another feature of my invention resides in its simplicity of construction and low cost of installation. An examination of the prior art will show that most desuperheaters are intricate in structure and expensive. a

It should be understood that the term desuperheated steam as used throughout this specification applies to steam which may be partially desuperheated and not necessarily to steam with 0 of superheat.

Further advantages and objects of my desuperheater will become apparent when the hereinafter description is read in the light of the following drawing, in which:

Figure 1 represents an elevational view of the desuperheater.

The superheated steam, or primary steam, enters the pressure reducing valve through the high pressure superheated steam line 11. The reducing valve 10 is provided with a flexible diaphragm which is contained in chamber 12, and said chamber communicates with the low pressure line 13 on the exit side of valve 10, by the conduit 14, thereby enabling the pressure reducing valve to be operated in conformity with the pressure in the low pressure steam line 13. The reducing valve 10 can be set by means of the nut 15 and spring 16 so that any pressure less than the pressure of the primary superheated steam can be maintained in the low pressure line 13. The de- 5 tailed construction of the valve 10 is well known and does not constitute a part of my invention.

A by-pass line 17 permits a portion of the primary superheated steam in line 11 to be passed through the flow control valve 18 and into the bottom of the secondary steam chamber 19, which is'partially filled with water. The by-pass line 17 projects through the bottom of chamber 19 and the end of said line terminates in a slightly tapered nozzle as shown at 20. A tapered sleeve 7 21 surrounds the nozzle 20 and is substantially coaxial therewith. The base of the tapered sleeve member is flanged, thereby enabling said sleeve to be rigidly fastened to the bottom of chamber 19 by means of rivets 22. Openings 23 are provided in the lower portion of the sleeve 21 so that water can be sucked into the sleeve and mixed with the superheated steam. A bafiie 24 is positioned above the sleeve member 21 but beneath the water level, thereby deflecting the steam leav- 5 ing the jet and securing intimate contact between the superheated steam and water with consequent evaporation of water and complete desuperheating of the steam. The saturated and wet steam rising from the lower portion of the secondary g0 steam chamber 19 passes through the bafile structure 24a located in the upper part of said chamber, whereby the entrained water is substantially removed therefrom. The baflies may be set so that some of the entrained water will be carried with the steam leaving the chamber. The steam formed in chamber 19, hereafter referred to as secondary steam, enters the secondary steam line 25 which communicates with the low pressure line 13.

The amount of steam bypas'sed through valve 18 is determined by the temperature in the low pressure line 13. A generator 26, which is filled with water or any suitable liquid, vapor or gas, is inserted in the low pressure line 13 on the down stream side from the lines 14 and 25, and communicates with the diaphragm chamber 27 by means of the conduit 28. As the temperature in .line 13 rises above the desired or predetermined temperature, the fluid in the generator expands and creates a pressure in chamber 27 and thereby causes the diaphragm contained in said chamber to actuate the valve 18 and increase the flow of superheated steam therethrough. The reverse operation occurs when the temperature in the low pressure line 13 falls below a desired or predetermined temperature. The fiow control valve 18 can be adjusted by the nut 29 and spring 30 so that any degree of superheat can be removed from the superheated steam after it leaves the pressure reducing valve 10. The detailed construction of valve 18 is well known and does not constitute a part of my invention.

Water is supplied to the secondary steam chamber through the pipe 31, and a constant water level is maintained in said chamber by a float contained in the casing 32. The float operates the check valve 33 through the levers 34, 35 and 36. A draw-01f line 37 is provided in the bottom of the chamber 19. Other draw-off lines may be placed in the bottom of the chamber, thereby insuring the removal of all sediment therefrom.

The operation of the desuperheater will be described by the use of a specific example, but it should be understood that this is not to be construed as a limitation upon the scope of this invention. superheated steam of about 400 pounds pressure per sq. in. and 600 F. enters the pressure reducing valve 10, and the pressure of said steam is reduced to 125 pounds, or any other desired pressure. A portion of superheated steam is by-passed through valve 18 and into the secondary steam chamber 19. The water in the secondary steam chamber is heated to boiling and the secondary steam generated therein passes through the bafiies 24a. and into the line 25 to the low pressure line 13 where the secondary steam is mixed with superheated steam discharged from the pressure reducing valve. A portion of the superheat in the low pressure steam is absorbed by the secondary steam and the resulting mixture of steam from the two sources contains less superheat than the primary superheated steam. The valve 18 is adjusted so that sumcient secondary steam will be generated in the chamber 19 to desuperheat the superheated steam introduced into the low pressure line 13 to the desired amount. It will be observed that the secondary steam is generated at substantially the same pressure as that existing in the low pressure lines.

If the temperature of the desuperheated steam in line 13, and particularly at the generator 26, rises above the desired temperature, the expansible material in the generator and in line 28 will expand and cause valve 18 to open wider and permit more superheated steam to pass into the chamber 19 so that the flow of secondary steam through line 25 will be increased, thus increasing the proportion of secondary steam introduced into line 13, and reducing the degree of superheat in the resulting mixture. The reverse of the above occurs when the temperature of the steam in line 13, and particularly at the generator 26, falls below the desired temperature.

If, for any reason, the pressure in line 13 falls below the desired pressure, or below the setting on valve 10, the diaphragm in chamber 12 actuates valve 10 and causes the pressure to be increased to the proper value in line 13. The reverse of the above occurs when the pressure in line 13 rises above the predetermined pressure.

By use of the above apparatus and method, I can generate desuperheated steam that is free from dissolved materials, becausethe secondary steam which is added to the superheated steam is free from dissolved solids. Also the turbulent action set up in the water contained in chamber 19 prevents scales from forming in said chamber,

and by use or" the draw-01f line 37, substantially all of the precipitated solid matter can be periodically removed from chamber 19.

While my invention has been described with reference to a specific example, it should be understood that my invention is limited only by the following claims.

I claim:

1. A desuperheater comprising, in combination, a high pressure superheated steam line, a pressure reducing means in said line, a low pressure line on the exit of said pressure reducing means, a container partly filled with water, a bypass line communicating with said high pressure superheated steam line and said container, said by-pass line terminating beneath the water level, an automatic flow control valve disposed insaid by-pass line and operated in response to the temperature of the steam in the low pressure line, a line communicating with the uppermost part of said chamber for passing steam to the low pressure line on the exit side of said pressure reducing valve.

2. A desuperheater comprising, in combination, a pressure reducing valve, a high pressure superheated steam line for passing steamto said valve, a low pressure line for passing steam from said valve, a secondary steam container partly filled with water, a by-pass line for leading steam from the high pressure superheated steam line to the body of water in said container, an automatic flow control'valve disposed in said by-pass line, a thermostatic means communicating with the low pressure line and said flow control'valve for operating said valve, a line for leading steam from the space above the water level in the secondary steam container to the low pressure line at a place between the pressure reducing valve and the thermostatic element.

,3. The method of continuously converting a stream of superheated steam from a high pressure and temperature to a condition of lower pressure and temperature, comprising passing a portion of it thru a pressure reducing valve into the low pressure line, passing the remainder into a body of water whereby a portion of the water is evaporated and saturated steam is produced, mixing said saturated steam with superheated steam in the low pressure line, and automatically controlling the amount of steam passed into the body of water in response to temperature variations of the steam mixture.

4. The method of reducing the temperature and pressure of superheated steam, which comprises reducing the pressure of a part of said superheated steam, reducing the temperature and pressure of another portion of said superheated steam by passing the same into an enclosed body of water, collecting the secondary steam generated from said body of water and mixing it with the low pressure superheated steam, and thermostatically controlling the amount of superheated steam passed into said body of water in response to the temperature of the mixture of superheated and secondary steam.

5. The method of reducing the superheat of superheated steam which comprises, passing a portion of said superheated steam into an enclosed body of water, removing the secondary steam generated from said body of water, reducing the pressure of the remaining superheated steam to a predetermined amount, mixing said reduced pressure superheated steam with said secondary steam, and in controlling the amount of superheated steam passing into said body of water in accordance with the temperature of said mixed secondary steam and said low pressure superheated steam.

6. The method of removing superheat from superheated steam which comprises, reducing the pressure of a part of said superheated steam to a predetermined value, passing the remaining superheated steam into an enclosed body of water and thereby generating secondary steam at a pressure substantially equal to said predetermined reduced pressuramixing said secondary steam with said low pressure heated steam, and in controlling the amount of superheated steam passing into said body of water in accordance with the temperature of said mixed secondary steam and said low pressure superheated steam.-

7. The method of removing superheat from superheated steam which comprises, reducing the pressure of part of said superheated steam to a predetermined value, passing the remaining superheated steam into an enclosed body of we.-

two streams, reducing the pressure in one stream to a predetermined amount without reducing the temperature thereof, reducing the temperature of the other stream, rejoining the two streams, controlling the flow of the first stream according to the pressure of the rejoined streams and controlling the flow of the second stream according to the temperature of the rejoined stream.

VANDERVEER. VOORHEES.

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