US1894391A - Desuperheater - Google Patents

Description

Jan. 17, 1933. .1. M. BARRETT ET AL 1,894,391

DESUPERHEATER Filed Oct. 29. 1927 ,2 Sheets-Sheet 1 Jan. 17, 1933. J. M. BARRETT ET AL 1,394,391

DESUPERHEATER.

Filed Oct. 29, 1927-. 2 Sheets-Sheet 2 Patented Jan. 17, 1933 UNITED STATES PATENT OFFICE JOSEPH M. BARRETT, OF CLEVELAND, AND GEORGE M. FRITZE, OF ORVILLE OHIO, ASSIGNORS TO THE SWABTWOUT COMPANY, OF CLEVELAND, OHIO, A CORIOBAH TION OF OHIO DESUPERHEATER Application filed October 29, 1927. Serial 150. 229,779.

This inventon relates to desuperheaters,

and more particularly to apparatus for adding water to superheated steam and to the control of such apparatus along with certain safety and warning devices to care for unusual or harmful conditions of operation.

It is among the objects of our invention to transform superheated steam to saturated steam or to reduce'the degree of superheat or transform superheated steam into steam of any desired quality. control the addition ofwater according to the degree of superheat. Another object is to provide adjustment whereby the uality or the degree of superheat of the out owing steam may be varied while the apparatus is in operation. Another object is to make the operation of the device as safe as possible, both with regard to adding enough water to reduce the degree of superheat and also with regard to the disposition of excess water for the protection of the prime mover or other steam consumin apparatus. Anotherobject is to provide a arm means for sounding a warning that certain auxiliary and protective,

apparatus has been brought into fise. A further object is to control the distribution of excess water which may have been added to the desuperheater. A further object is to make the connections between the thermal control means and the steam line such that they can be readily removed or exchanged. A still further object is to control the flow of water to the desuperheater so that it will flow in proportion to a given valve opening regardless of the pressure in the desuperheater or in the water line. Another object is to regulate and limit the water valve travel so that for a given operation certain limits will not be exceeded.

Other objectswill appear from the following description of the apparatus embodied in our invention, a preferred form of which is illustrated inthe accompanying drawings. The essential characteristics-are summarized in the claims.

In the drawings, Fig. 1 is a layout ofthe piping and'apparatus employed in our invention; and Fig. 2 is a section of the main Another object is to water valve with connections to a pressure generator positioned in the steam line.

Referring particularly to Fig. 1, we show a steam line 1 into which superheated steam flows. as indicated. In this line we place a reducing valve 5. The desuperheater proper is indicated at 2, and for the sake of our present invention may be described as a chamber into which superheated steam and water are directed, and therein mixed so that the superheat is consumed in vaporizing the cold water. Leading from the chamber 2 is a steam pipe 4 through which saturated steam or at least desuperheated steam is discharged. The chamber 2 has a lower outlet 3 connecting to a steam trap or, reservoir 6. A conduit 28 leads into the top of the chamber 2 and comprises the water inlet for the chamber. Water is supplied from sources not shown at a pressure higher than steam pressure and may flow through conduits 29 or 30 or both from such sources. A valve 31 controls the flow of water throu h the conduit 30 and a valve 27 controls the ow of water through the con- 7 As mentioned above, excess water from the mixing. chamber 2 descends into the-steam trap 6. Leading from the steam trap 6 is a conduit 7 which branches through a T-con-' nection through conduits 8 and 9 respectively. A valve 10 controls the flow of water through the conduit 8 and a valve 11 controls the flow of water through the conduit 9. In practice, we have found it advantageous to use the conduit 9 and the valve 11 to control the normal flow of water back to the hot well or its equivalent and to use the conduit 8 and the valve 10 as an emergency device or to direct excessive quantities of water to water storage or to any other desired point,

Thermal control means such as a pressure generator of the general type disclosed in patent to Copley No. 1,193,125 ,may be at.- tached to the reservoir or trap -6 to control the valves 10 and 11. The valves may be of a diaphragm actuated type which are held open when idle by springs 12 and 13. Dia-,

ne cted through conduits 18 and 19 to exert pressures on the diaphragms 14 and 15 respectively. The generator 16 being mounted at a higher elevation than the generator 17, so that in normal operation when the water level is substantially along the line L-L, the generator 17 controls the opening in the valve 11. In the event of an excess of water, the generator 16 will be brought into operation as the water level approaches the line MM. The-operation of such a drainage control is disclosed in the co-pending application of Joseph M. Barrett, Serial No. 149,439, filed November 19th, 1926.

The operation of this drainage control is that both valves are normally held open by the springs 12 and 13, as mentioned above, but when steam is present in the tank or trap 6, the generators 16 and 17 are heated and pro duce pressures in the diaphragms 14 and 15, which close the valves. The valves being closed, water is accumulated in the tank 6 until the water level rises successively past the levels L -L and M-M in the generators and reduces the pressure, thuspermitting one or more of the valves to open. Our thought is here to use the valve 11 for normal operation and to reserve the valve 10 to take care of excessive amounts of Water or to take care of all of the discharge from the tank 6 in the event the valve 11 fails to perform.

e also provide an alarm, which may be electrical, to sound a warning that the valve 10 has been brought into action so that the operators attention is brought to the state of the apparatus. The alarm includes a pressure gauge 20 connected to the conduit 18 and having electrical contacts on the dial which may be set at any desired position so that a fall in pressure on the diaphragm 14 to a predetermined minimum, closes the alarm circuit. The alarm may comprise a gong 21 to which is connected a lead 22 which crosses the gauge and extends to a storage battery B or other source of current.

As mentioned, the inflowing water passes through conduits 29 or 30, the conduit 30 being the main or normal conduit while the conduit 29 is held in reserve to act in an emergency- Both conduits join in the conduit 28 vAs ointed, out above, the valve 31 controls the ow of water through the conduit'30. The valve 31 being of the diaphragm actuated type is controlled by thermal meanssuch as the pressure generator 60 which is positioned in the superheated steam line so that the flow of water flowing through the valve 31 is controlled according to the degree of superheat of the incoming steam.

The thermostatic means 60 (see also Fig. 2) is a modified form of fluid pressure generator associated with the steam line 1. A conduit 61 extends into the steam line having an 7 enlarged orificefacing the flow of steam. The conduit 61 leads to a chamber 62 and a return eeaaea conduit 63 leads back to the steam line so that the steam flows through the chamber 62. Suitable valves '64 and 65 are positioned in the conduits for controlling the flow of steam. These valves may be closed to permit removal or repair of the generator. A blow-down valve 66 is also provided. Passing through the chamber 62 is a conduit 67 which ma be welded into the ends of the chamber or ot erwise suitably secured, and which is joined to a smaller conduit 68. The conduit 68 leads to a reservoir and cooling chamber on which are secured radiating fins 71. The conduit 68 continues to a diaphragm chamber 50 of the valve 31. A filling plug 69 is provided in the uppermost part of the conduit 67. An

air vent or plug 51 is provided in the diaphragm chamber 50. The conduits 67 and 68 along with the reservoir or cooler 70 and the diaphragm chamber 50 are filled with water through the plug 69, a small quantity of air being trapped in the uppermost part of the conduit 67 When the valves 64 and 65 are opened, superheated steam flows through the chamber 62 thereby heating the fluid in the conduit 67 and causing pressure to be exerted on the diaphragm of the valve 31. The pressure thus generated will vary according to the temperature of the steam, or more accu-. rately according to the quantity of heat delivered from the steam to the fluid in the conduit 67.

To control the inflow of water through the conduit 30, (see Fig. 1) we provide a valve 31 and adjacent this valve and nearer the source of water supply than the valve, we provide a differential valve 32 which may be similar to that described in the co-pending application of Joseph M. Barrett, Serial No. 105,423, filed April 29th, 1926. The valve 32 is of the diaphragm actuated type and has an adjustable excess pressure means comprising a spring 33 tending to urge the valve to open position. Opposed to this excess pressure, is directed the pressure of water which has just passed through the valve 32, and acting in conjunction with the excesspressure is directed the pressure of the water leaving the valve 31. To exert this last named pressure, a conduit 35 is provided, the flow through which is 0011- trolled by a suitable auxiliary needle valve 36..

Another needle valve 37 with an auxiliary conduit 38 is provided so that the pressure before the valve 32 may be substituted for the pressure beyond the .valve 31 to throw the valve 32 wide open. In normal-operation, however, the pressure drop across the valve 31 is determined by the com ression of the spring 33 so that the pressure ait the point 19, between the two valves, is always a certain amount in excess of the pressure in the chamber 2 regardless of the pressure of the supply.

of water. In this manner, we are able-to'obtain and maintain a very accurate regulation of the character or quality of the desuperheated steam regardless of the variation in steam pressure or water pressure.

Referring more particularly to Fig. 2, we show in detail the valve 31 along with thermalmeans 60, mentioned above. The valve 31 comprises a body portion 41 in which are mounted suitable valve seats 42 against which the valve member 43 may rest. A casing extension 41a is mounted on the valve body. A valve member is actuated through a rod 44 which has a' mushroom shaped head 45 in contact with the flexible diaphragm 46. A spring 47 is compressed between the mushroom head 45 and a yoke 48. The yoke 48 is mounted on ascrew 49 which extends longitudinally of-the casing and the rod and hasa head 50 by means of which the yoke 48 may be moved so that the stress in the spring 4 may be varied as desired. A fluid passageway is provided from the outlet side of the valve and back through the body and through the casing 41a to the inner side of the diaphragm 46.. The fluid pressure of the outflowing waterand the spring pressure 47 act conjointly on the diaphragm in a direction to close the valve. On the opposite side of the diaphragm is a closed chamber 50 having a suitable vent plug 51, to which chamber, leads the conduit 68 from the pressure generator.

On the opposite end of the valve, we have provided means for defining the range of valve movement within a certain predetermined limit so that under given operating conditions, a maximum or minimum limit for valve opening may be set. The valve member 43 may have a threaded extension 80 on which may be secured a yoke 81. Between the ends of the extension 80 and confined within the end of the yoke, may be an enlarged head 82 carried by a pin 83. The pin 83 has a hand wheel 84 and is in threaded engagement as at 85 with a yoke 86, which in turn is mounted on the body of the valve. When the pin 83 is moved downwardly to its lowermost position, it will'be seen that the valve member 43 is held onto the valve seats 42, and in this osition the valve 31 is maintained closed. f on the other hand, the in 83 is raised so that the head 82 is carrie to its uppermost position, the valve membeiij43 is raised from the seats and'is maintained there regardless of the actuation of the diaphragm 46. The travel limit of the valve 43 is determined by the relation between the length of the .yoke 81 and the length of the extension 80 so that the valve movement may be adjusted between these limits as desired; It will be seen that the range ofvalve travel may be governed by turning the hand wheel phragm 46 is substantial fluid pressure on the up er side of the diaequal to the pressure in the chamber 2, w ich in turn equals the steam pressure. In other words, the resultant force tending to move the valve open depends upon the degree of superheat in the steam, since the temperature and pressure of saturated steam vary uniformly and since the pressure in the chamber 50 exceeds the pressure which would be generated by the temperature of saturated steam according to the degree of superheat. Or viewed from another angle, the pressure exerted by the spring 47 is a measure of the degree of superheat when dry saturated steam is delivered.

That is, the spring 47 is adjusted to close the valve 31 if the degree of superheat dropped to zero when dry saturated steam was "required to be delivered. The spring 47 may be controlled by the screw 49 to correlate or compensate for the difl'erent nature or causes of pressure on the diaphragm 50 so that the valve opening may be a function of the degree of superheat.

The normal operation of the apparatus is that steam is directed through pipes land 4 including the chamber 2, and part of it passing through the generators 60 and causing the valve 31 to open. This permits a certain quantity of water to flow which may be varied according to the compression of the spring 47. Thus to obtain steam of any desired quality or degree of superheat, the compression of the spring 47 may be varied and after that, the valve openin will vary according to the degree of super eat entering through the pipe 1. Stated more broadly the valve opening varies according to the difference in temperature between the inflowing and outflowing steam. The excess water is accumulated in the receiver 6 and disposed of as mentioned above.

We provide for the contingency that the source of supply providing water for the conduit 30 may fail or that for some unforeseen reason the valve 31 may deliver an insuflicient amount of water. An auxiliary conduit 29 is provided, which may preferably lead from an independent source of water supply. A diaphragm actuated valve controls the flow of water through the conduit 29. This valve has a spring 28 normally holding it closed and has a diaphragm in a chamber which is connected by a conduit 68a to a reservoir 70a similar to the reservoir 70 and to a thermostatic means or generator 60a, which may be a duplicate of the thermostatic 'means or generator 60. The spring 28 of the valve 27 is set so that the valve is held closed as long as less than a predetermined pressure is generated in the generator 60a. The generator 60a, is positioned as shown in the desuperheated steam line 4 and the spring 28 off the valve 27 is set'to maintain the valve closed as long as steam of no greater than acertain predetermined temperature passes through the steam pipe 4. If however, through a failure of water supply, the steam is not desuperheated as desired, the pressure in the generator 60a will be increased to overcome the pressure of the spring 28, which will open the auxiliary water line to add water to the chamber 2. t

A pressure gauge or like means 90 is associated. with the conduit 68a; the gauge 90 may have a suitable electrical contact so that a current may fiow from the battery B through the line 91, through the gauge 90, into an alarm means 93 which will call the operators attention to the fact that the auxiliary water supply is being used.

It will be seen from the foregoin that our desuperheater is arranged to deliver desuperheated steam of any desired characteristic or quality; that ordinarily the addition of water to the superheated steam will be controlled according to the degree of super-heat; that we have provided means for eliminating an excess of water and that we have provided additional means for insuring the supply of suflicient water and that we have insured a safe and satisfactory operation by causing the alarm to sound or indicate in the event that either of the safety devices are called into operation.

Changes in structure will appear to one skilled in the art, and while we have shown a preferred form of our invention, we do not care to be limited in the scope thereof, other than by the claims appended hereto.

I claim:

1. The combination of conducting means through which superheated steam may flow, means for supplying water to said conducting means for lowerin the temperature of said steam, and means %or varying the supply of water according to the degree of superheat of said steam in excess of the temperature of dry saturated steam.

2. The combination ofconducting means through which superheated steam may flow, means for supplying water to said conducting means to desuperheat the steam, and means for regulatin the supply of water according to the 'norma saturated steam pressure and the temperature of superheated steam.

3. The combination of steam conducting means into which superheated steam may flow, means for supplying water to said conducting means, and means responsive to the diflere'nce between the temperature of the superheated steam and the. temperature of the desuperheated steam for regulating the supply of water.

4. The method of controlling the addition of-water to superheated steam to change, the same to saturated steam which comprises gene'r ating a fluid pressure with the superheated steam, opposing the pressure so generated by the normal saturated steam pressure, and directing the resultant difierential pressure to regulate the flow of water.

5. In a desuperheater, a mixin chamber, means for supplying water to'sai chamber,

a steam trap for said mixing chamber,.con-

duits leading from said steam trap to different points for the disposal of water therefrom, and means for selectively distributing the flow of water from said trap to said points according to the rate of accumulation of water in'said trap.

6. In a desuperheater, comprising a mixing chamber, having an inlet and outlet for steam and having an inlet and outlet for water, at least a pair of conduits leading to said water inlet, valves in each of said'conduits, at least a pair of conduits leading from said water outlet, valves in each of said last named conduits, means for selectively controllin said inlet water valves to reduce the temp rature of superheated steam, and means for selectivel opening said outlet water valves according to the rate of accumulation of excess water from said mixing chamber.

7. In a desuperheater, comprising a mixing chamber through which steam may flow, a main water. conduit, an auxiliary water conduit, means for controlling the flow of water through ,said main conduit, means for controlling the flow of water through said auxiliary conduit according to the character of desuperheated steam, and alarm means assocfated with said last named means to warn 3f the flow through said auxiliary water conuit.

8. In a desuperheater. comprisin a mixing a 9. A desuperheater having a main water supply and an auxiliary water supply, a normal outlet for excess water and an auxiliary outlet for greater than hormal amounts of excess water, alarm means associated with said auxiliary water supply, and alarm means associated with said auxiliary water outlet.

10. In a desuperheater, the combination of a mixing chamber having an inlet for superheated steam and an outlet for desuperheated steam, a conduit for water at greater pressure than the fluid pressure in said chamber and leading to said chamber, a valve in said conduit for controlling the flow of water therethrough, said valve being responsive to the pressure of the water flowing there'- through, a second valve for icontrollingthe pressure drop across and'the pressure in said first named valve and means responsive to the temperature of the steam for controlling said first named'valve.

11. A desuperheater through which superheated steam flows including a conduit through which water is delivered, a valve in said conduit and means dependent upon the temperature of the steam for controlling said valve and adjustable means for limiting the valve movement regardless of the temof water thereto including a diaphragm actuated valve having a diaphragm, means for exerting upon one side of the diaphragm fluid pressure substantially equal to that of the mixing chamber, means for exerting an adjustable excess pressure on the same side of the diaphragm tending to close the valve and means for exerting on the other side of the diaphragm afluid pressure variable according to the degree of superheat.

13. A desuperheater comprising a mixing chamber for water and superheated steam, means for controlling the inflow of water thereto including a diaphragm actuated valve having a diaphragm, means for exerting upon one side of the diaphragm fluid pressure substantially equal to that of the mixing chamber, means for exerting an excess pressure on the same side of the diaphragm tending to close the valve and means for exerting on the other side of the diaphragm a fluid pressure generated by the superheated steam.

14. In a desuperheater, the combination of a mixing chamber for water and superheated steam, a water conduit leading to the chamher, a valve in said conduit, means for controlling the pressure drop across said valve, a diaphragm for actuating said valve, a chamber for enclosing one side of said diaphragm and communicating with the outlet side of said valve, a spring within the chamber bearing against the said diaphragm and tending to close said valve, a screw for adjusting the compression of said spring, a chamber enclosing the opposite side of said diaphragm, a closed vessel disposed in the path of the superheated steam and communicating with said last named chamber whereby the valve is forced open When the pressure in said last named chamber exceeds the pressure in the spring chamber and the pressure exerted by said spring.

15. In a desuperheater having a mixing chamber for water and steam, a water conduit leading thereto, a valve in said conduit, a diaphragm for actuating said valve, means for exerting a fluid pressure on one side of said diaphragm to open said valve including a vessel containing fluid disposed in the path of superheated steam and a conduit leading from'said vessel to a chamber enclosing said diaphragm, and means for exerting on the opposite side of said diaphragm a fluid pressure proportionate to the steam pressure insaid desuperheater.

16. In a desuperheater, the combination of a mixing chamber for water and steam, a water conduit leading to said chamber, a valve in said conduit, a diaphragm disposed in a diaphragm chamber for opening said valve, means including an adjustable spring tending to close said valve, a closed vessel disposed in the path of the steam and containing an expansible fluid, a conduit leading from said closed vessel to said diaphragm chamber and a fluid cooling and storage vessel disposed in said'conduit.

17. A desuperheater having in combination a mixing chamber, a water pipe leading thereto, a valve in said Water pipe, means for maintaining the water pressure ahead of said valve at a predetermined amount in excess of the steam pressure in said mixing chamber, means for controlling the valve opening and means for discharging an excess of water delivered to said mixing chamber.

In testimony whereof, we hereunto aflix our slgnatures.

JOSEPH M. BARRETT. GEORGE M. FRITZE.

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