US2321390A

US2321390A - Flow-through tubular steam generator

Info

Publication number: US2321390A
Application number: US308770A
Authority: US
Inventors: Juzi Viktor
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1938-12-13
Filing date: 1939-12-12
Publication date: 1943-06-08
Anticipated expiration: 1960-06-08

Description

June 8, 1943. v. JUZI mow-THROUGH TUBULAR STEAM GENERATOR Filed Dec. 12, 1939 3 Sheets-Sheet 1 Pre/)eater MDmmwmm",

ATTORNEYS June 8, 1943.

V. JUZI FLOW-THROUGH TUBULARv STEAM GENERATOR Filed nec. 12. J1939 4 s sheets-sheet 2 Jacoba feparaor fra/ponder www Tz I..N mf A M June 8, 1943. vv. Juzl FLOW-THROUGH TUBULAR STEAM GENERATOR Filed Dec. l2, 1939- 3 Sheets-Sheet 3 ATTORNEYS Patented June 8, 1943 FLOVV-THROUGH TUBULAR STEAM GENERATOR .Viktor Juzi, Winterthur, Switzerland, assignor to Sulzer Frres, Socit Anonyme, Winterthur,

Switzerland Application December l2, 1939, Serial No. 308,770

In Switzerland December 13, 1938` Y 7l Claims.

The invention relates to a flow-through tubular steam generator having a tube system to which two separators are connected. The separator that carries olf the injurious constituents from the working medium is arranged in the evaporation zone and the separator which eects a drying of the steam is located at the beginning of the superheating zone. The liquid discharge conduit being connected to and arranged to means operatively connected to a common temperature-responsive device actuated by the steam flowing to the second separator. The temperature-responsive device may be connected to the tube system between the separators. Advantageously, the rstiseparator has aconduit provided with a throttling device which regulates the uniformity of flow therethrough, said conduit being 'connected to and arranged to pass a portionY of the separated liquid to a lowpressure stage of the plant. The rst separator is preferably provided with a second conduit having a control valve underithe operation of the temperature responsive device. The second separator has a conduit;v for returning Vcondensate to the feed water'tank of. the steam` generator. The conduit for returning the condensate preferably is controlled by a valve actuated by the temperature responsive device.

The invention 'assures a proper de-salting ofV the working medium.A It also prevents liquid particles from being carried along by .the steam into the superheater or the points of consumption. Still another object of the invention comprises assuring a dependable control of the steam temperature. The invention will also permit proper cooperation between the de-salting of the working medium and the control of the boiler operation.

Fig. l of the accompanying drawings is a diagrammatic illustration of an arrangement of a tubular steam generator system embodying the invention.

Fig. 2 shows the details of the regulation of the discharge from the two separators.

Fig. 3 shows the details of the regulation 0f the quantities of steam taken from the steam generator.

The steamv generator system illustrated in Fig. l comprises feed pump I which pumps feed liquid through the feed conduit 2 into the preheater 3. The preheated liquid, which under certain circumstances'is already evaporated in small amount, then passes through the conduit 4 into the evaporator 5, in which a larger amount is evaporated so that only a smaller amount passes "i .in liquid form into the rst separator 6. A conduit I provided with a throttling device 8 of constant cross section conveys a portion of the separated liquid into the tube system I0 that is connected to a low pressure stage (not shown inthe drawings) of the steam power plant. Another portion of the liquid is led off through the conduit i l, which can be closed by means of the valve l2, into the feed tank i4. The portion of the liquid that is not led off from the separator 6 is mixed again with the steam and passes into the re-evaporator it. At the end of the re-evaporator a slight superheating of the steam occurs. From the re-evaporator the steam flows through athermostat (tube loop) Il into the second separator I8. Liquid separated in-each casecan be led from the separator I3 into the feed tank I4 vthrough the conduit l! that can be closed by means of a valve 20. Only the vaporous portion of the Working medium ows from the second separator into the superheater 2l, inl which it is brought to the temperature required for use and after flowing through the thermostat (tube loop) 22 passes through the conduit 25 into the power engine plant 26. After expansion of the steam in the engine plant 26 it is ledthrough the conduit 2l into the heat'exchanger 28, from which the condensate is conveyed-intothe feed tank I4 through the conduit 29 by the Vcondensate pump The heat evolving in the heat exchanger 28 from the high pressure working medium is transmitted to the workingfmedium evolving from a low pressure stage of the steamu plant.

The thermostat Il rst traversed by the steam inuences by aid of the impulse sender 35 via the conduit 36 the servomotor 3l of theregulating valve 38.- -Furthermore, by the impulse sender 35 via the conduit 39 the regulating devices 4l of the furnace 42 can be influenced and via the conduit 43 the servomotor 44 yof the valve 20 in the conduit -lI of the second separator can be influenced. Furthermore, vi-afthe conduit 44a the servomotor 45 of the valve |2 in the conduit, Il. may be controlled. The thermostat 22 influences-by aid ofthe impuse sender 4t via the conduit 41 thel servomotor 48 of f a flow-through valve y49 ,in` the conduit 5l. Throughthe conduit 5|, in dependence on the superheating temperature,v a larger or smaller amount of additional working medium is injected from the feed conduit 2 into the tube system of the steam generator 4at the point 52. The limpulse sender v4S can furthermore influence via the conduit 53 the servomotor 54 of the flow-through valve 55 in the steam conduit 25 and can inuence via the conduit 55 the servomotor 51 of the ow-through'valve @il in the by-pass conduit 6l.

By aid of the pressure impulse sender 62 the servomotor 54 of the flow-through valve 55 is inuencedin such a way that with increasing pressure in the conduit 6| Van increased passage cross-section of the valve is adjusted and that with decreasing pressure a diminished passage cross section of the valve is adjusted. If it should not be possible to prevent an increase of the pressure even when the Valve 55 is completely opened, then the pressure impulse sender 62 iniluences also the servomotor 51 so that on further increase also the overflow valve 60 is opened and from the conduit 25 the steam can flow directly to the steam heat exchanger 28.

By aid of the two thermostats I1 and 22 the supply of feed medium through the feed conduit 2 and through the injection conduit 5| is regulated in such a way that the temperature of the steam flowing to the points of consumption keeps an unvarying equilibrium level. If. for example, the temperature should rise above the equilibrium level, then by aid of the thermostats a larger amount of feed liquid and injection liquid is adjusted so that the temperature is again lowered to the equilibrium level. Conoversely, when the temperature falls the amount of feed liquid and of injection liquid is diminished land thereby the temperature is again raised; to the equilibrium level.

The lengths of the tubes of the preheater 3,

of the evaporator 5, of the re-evaporator I6 and ofthe superheate'r 2| are so dimensicned with respect to the heating by the furnace 42 and the supply of feed liquid through the conduit 2 land of injection liquid through the conduit 5| 'If a temperature is reached that is lower than Va definite temperature limit at the `exit from the re-evaporator (which, for example, can be about 30%V abovethe saturated` steam temperature), then by aid of the thermostat II, of the impulse sender 35 and of the servomotors 44 and 45, the

Aflow-through valvesV 29 or I2 are opened so that the excess waterflowing through the tube system can again be led back to the feed tank I4.

At the same time by the impulse 'sender 35 the cross section of the feed valve 38 is diminished to such an extent Vthat the fall of temperature, which'has caused'the discharge of liquid from the two separators 6 and I6, is again eliminated and as a consequence the fvalves 2U and I2 are againA closed. Accordingly, the flow displacements or pulsations which are icaused in the tube vsystem of through-flow steam generators in consequence of temperature regulating devices during operation are Vthereby compensated. The temperature-responsive devices can also be connected to ,the tube system before the first separatory or behind the second separator.

The'control apparatus illustrated in Figs. 2 and 3 comprises control members or valves |23, |60, |6I, |62,'|63, |32, |64, |65, |45, |66 and |61 and servomotors having cylinders |53, I3I, |28, |25, |34, |42 and |39 which are supplied with acontrol liquid: such. as foil under pressure through conduits |68. The liquid is supplied from a pressure system not shown and a suitable pressure is maintained toY operate the various pistons Aas willv hereinafter be described. Each of thecpntrolmembers is connected to a discharge conduit |69 into which'the liquid flows as will hereinafter be described. The conduits |69 are preferably connected to a conduit system permitting the liquid to be returned to the pressure system which supplies the liquid to the conduits |68. Ordinarily, the liquid is discharged into the conduits |59 at normal atmospheric pressures.

The piston valve 2|8 (Fig. 2) of the valve |23 is loaded from below through the control pressure existing in conduit 36 and from above through spring 2|9. When the temperature of the steam flowing through tube loop of the thermostat rises and the loop consequently gets longer, valve piston 2|8 is pushed downwards, compressing spring 2|9, and a connection is established between inletconduit |68 and control conduitl 36 through the openings 2 Ia, in control valve piston 2|S, In this way the control pressure in conduitl 36 rises, so that piston 2I8 is again raised until the increased control pressure corresponds to the increased tension of the sprin'g and consequently to the increased temperature. In the opposite case, if the temperature of the steam flowing through tube loop I`| falls and the loop consequently becomes shorter, the tension of spring 2 I9 is reduced. The control pressure pushes piston 2|8 so far up that'liquid can escape from conduit 36 to outlet conduit |69 as long as the reduced pressure in conduit 36 corresponds to the reduced temperature of the steam.-

springs

224, 225, 226 or'22'I when -the liquid pressure in conduit 36 rises, and on the contrary the pistons move downward when the liquid pressure in conduit 36 becomes lower.

A rising of the pistons as described causes inlet conduits |68 to connect with the cylinders |25, |53, ISI-'and |28 and the liquid pressure `therein to raise

pistons

228, 229, 230 or 23| closing Valves I2 and 20, opening valve 38, and closing damper 4|a. By reason of the increased feed water admitted through valve 38 andthe reduced air admitted through damper 4I'a, the temperature of the steam issuing from the steam generator is again brought back to normal. In addition to that, the quantity vof liquid led away i from the separators 6 and I8 is reduced.

When the temperature of steam in loop I'I falls, the piston 2|8 rises, connecting conduit 36 with'conduit |69 and the liquid pressure acting on all the pistons 226-223 decreases causing them to descend. The corresponding cylinders |25, |53, |3| and |28 are connected to discharge conduits |69 so that the respective servomotor pistons 22S-23| begin to descend, opening damper 4|a, increasing the furnace combustion, closing valve 38, reducing the quantity of feed water,'thus causing a proper adjustment of the'steam temperature. At the same time valves I2 and 20 are opened, so that a greater quantity of water can be discharged from Athe separators.

Tube loop 22 of the` thermostat (Fig. 3) acts on piston I`|| of valve |32 due to changes in its length in consequence of changes in temperature with corresponding changes in the tension of spring I'IIJ. A rising temperature causes tub 22 to lengthen, so that spring |10 is more compressed and piston |`II is pressed downwards.

When the temperature of the steam falls, loop 22 shortens and the tension in spring |18 is reduced. In this way piston |1| is raised, so that liquid flows into conduit |69 from conduit 56 until the desired regulation is established.

The result is therefore that with rising steam temperature the pressure in control conduit 55 rises, and in the contrary case with falling steam tempera-ture the pressure in conduit 56falls, with the result that, for any temperature of the steam owing through loop 22, there is a corresponding liquid pressure in conduit 55.

The pressure responsive member |45 has a iston |13 which is connected to a plunger |14. This plunger is under the influence of the pressure in conduit 25, which pressure is transmitted to the cylinder of the plunger through conduit |15.

With rising steam pressure the plunger |14 and the piston |13 are raised.- Liquid under` pressure then Hows from conduit, |68, through opening |13a and into conduit |16, causing the pressure therein to rise. With falling steam pressure in conduit 25, the said piston and the plunger are forced downwards. From conduit |16 liquid can flow to conduit |69 until the reduced liquid pressure in conduit |18v corresponds to the reduced steam pressure in conduit 25.

By means of a hand-operated adjusting device |11, the spring |18 can be given more or less tension. By increasing the tension, the liquid pressure in conduit |16 is reduced; by reducing u the spring tension, it is increased. The result is that the liquid pressures in conduit |16 rise or fall respectively with the steam pressuresin conduit 25, and that, for adjusting to the proper value, the liquid pressures, corresponding to the steam pressures, can be variously adjusted by means of the hand-operated adjusting device I 11.

The liquid pressure in

conduits

56, 41, 53 and 56 acts on pistons |19, |88 and |8| of control members |54, |95 and |55.

|83 and |84 respectively. Consequently with rising liquid pressure or rising temperature of the steam owing through tube loop 22, liquid can flow from the pressure-liquid system |68 into control conduits |85 and (under certain conditions) |86. On the other hand, liquid ows away from these conduits to drain system |69 if the liquid pressure or the steam temperature in tube loop 22 falls. The liquid pressures in conduits |16, |81 and |88 act upon pistons |89 and |98 of the control members |66 and |61 respectively, in such away that, when the liquid pressure increases. they are raised against springs |9| and |92 respectively. In this way, with rising liquid pressure or rising steam pressure in conduit 25, liquid can enter from the pressure-liquid system |68 into control conduits |93 and |94 respectively. On the other hand. liquid ows away from conduits |93 and |94 respectively to drain system |69 if the liquid pressure or the steam pressure in conduit 25 falls,

ton stands in its upper position providing a constantconnection between 'conduit |94 and conduit |86.v

Piston |88 of control member |95 has annular surface |96 under the control `pressure from conduit 56, a surface |91 under the liquid pressurein space |98, and a spring |83 opposing the liquid pressure. The piston remains during normal service so far down that there is always a connection between conduits |93 and |99. Only if the liquid pressure in'conduit 56 exceeds a certain amount, and in consequence piston |88 is raised, liquid under pressure can pass from conduit 288 through space and groove 282 into space |96. In this way the piston is pressed into its top position and there it remains. Then there is a permanent connection between conduits |99 and 288. The piston can be pressed downwards only by means of knob 283, and then the medium under pressure in space |98 flows through passage 284 into discharge conduit |69.

Servomotors |34, |39 and |42 have each a piston 285, 286, and 281, and these pistons are influenced on the annular surfaces'288, 289 and 2|8 by pressure from conduit |58 and on the piston surfaces 2H, 2|2 andv 2|3 by pressure from control conduits |85, |86 and |99. The pistons can be raised by hand by means of the adjusting devices 2|4, 2|5 and 2|6.

The apparatus shown inFig. 3 works as follows under normal conditions:

If the temperature of the steam flowing through loop 22' rises, piston |19 of control member |64 is raised by the rising liquid pressure in

conduits

56 and 41. From conduit |58 oil under pressure can pass through conduit |85 under the piston 285, so that the cone of valve 49 is raised. In this way the feed water introduced to the steam generator through conduit v5| is increased. t

With reduction in temperature of the steam lowing through loop 22, the reduced control pressure in

conduits

56 and 41 allows the piston to move downwards. In this way servomotor |34 is connected through conduit |85 to discharge conduit |69. Servomotor piston 285 moves downwards and the cross-section of Valve 49 is decreased, and the water introduced to the steam generator through conduit 5| is decreased.

If the steam pressure in conduit rises higher than it should, the liquid pressure in conduits |15, |81 and |88 also rises. Springs |9| and |92 are so strong relatively to each other that rst of all the piston |98 is raised In this way liquid can pass from conduit |68 under servomotor piston 286. The cone of valve is raised, so that a greater quantity of. stearn can flow away through conduit 25 until the pressure has again been brought back to the proper amount.

If the correct steam pressure, however, can no longer he obtained whenvalve 55 is fully open, i. e. if the steam pressure in conduitl 25 then still continues to rise, the piston |89 is also raised so high that oil under pressure can pass from conduit |68 through conduits |93 and |99 under servomotor piston 281. In this way the cone of valve 68 is raised, so that steam can flow from conduit 25 direct to-the condenser through bypass |44 until the correct steam pressure has again been reached.

Ii the pressure in conduit 25 falls, in consequence of the falling liquid pressure, piston valve |89 is rst of all pressed downwards again by spring |9| until servomotor |42 is connected with discharge conduit |99 through conduits |99 and |93. Servomotor piston 201 then falls and reduces the cross-sectional area of flow of valve 60 until the pressure in conduit 5| has risen to its proper value. I

If valve 60 has closed entirely without the correct pressure being reached, piston valve |90 also begins to descend, so that still another connection is made between servomotor |39 and discharge conduit |69 through conduits |86 and |94, Then, through the falling of servomotor piston 206, the cross-sectional area of flow of valve 55 is reduced, and this is eiected until the correct pressure is restored in conduit 25.

Under abnormal conditions, i. e., if the temperature of the steam flowing through conduit is too high or too low, the impulse sender 46 also takes part in the regulation.

Assuming that the temperature is too high, theliquid pressure in conduit 56 then becomes high and raises piston valve |89, thus creating a permanent connection between feed conduit |68 and conduit |99. Valve 51 is thus fully opened, so thai; all steam can flow away to the condenser from conduit 25 through conduit |44. The pressure in conduit 25 will at once fall, and thus the control pressure in conduits |16, |81 and |88 also falls and servomotor |39 is connected to discharge conduit |69 through conduits |86 and 2I1. In this way, when the temperature is too high, Valve 60 is completely opened, and valve 55 completely closed, until, after a normal temperature has been restored, knob 283 and thereby also control piston |80 have been again pressed down by hand.

When the temperature is too low, the control pressure in

conduits

56 and 53 becomes lower, so that piston valve |8| moves downwards, thus creating a permanent connection between servomotor |39 and discharge conduit |69 through conduits |86 and 2|1, Valve 55 is thus closed and the pressure in conduit 25 begins to rise. In this way valve 69 is raised, so that by letting off steam from conduit 25 through conduit |44 the correct pressure in conduit 25 is again restored.

After the temperature in conduit 25 has risen again to its normal value, piston I 8| is raised, so that valve 55 is again controlled normally by the pressure, and steam can flow awatr through conduit 25.

I claim: Y

l.. In a flow-through tubular steam generator which comprises a tube system including an evaporator and a superheater, a first separator connected in the evaporator, a conduit provided with a throttling device for carrying off injurious components of the feed water, a second conduit connected to the first separator for discharging liquid, a second separator for drying the steam connected at the beginning of the superheater, a conduit for the discharge of condensate from the second separator, a regulating valve in the second conduit and another regulating Valve in the discharge conduit connected to the second separator, a device responsive: to the temperature of fluid entering the second separator, and means operatively connecting the device responsive to temperature to each regulating valve.

2. A flow-through tubular steam generator according to claim 1 which comprises a plant having a low pressure stage, and means for trans- 'mitting the heat of fluid discharged from the first separator through the conduit provided with a throttling device to the low pressure stage of the plant.

3. A flow-through tubular steam generator according to claim 1 which comprises a feed tank, and means for passing fluid discharged from the second separator to the feed tank of the steam generator,

4. In a flow-through tubular steam generator which comprises a tube system having an evaporator, a re-evaporator and a superheater, a iirst separator connected between the evaporator and the re-evaporator, a heat exchanger, means for passing liquid from the first Separator to the heat exchanger, a valve controlled conduit for discharging liquid from the first separator, a device responsive to the temperature of uid owing from the re-evaporator arranged to operate the valve, whereby an unevaporated residue may be removed from the uid passing through the evaporator, a second separator arranged to receive fluid from the re-evaporator and pass it to the superheater, a valve controlled conduit for discharging liquid from the second separator, a device responsive to the temperature of the fluid flowing from the re-evaporator arranged to actuate the valve in the conduit for discharging liquid from the second separator, and means for returning liquid discharged from the second separator to the evaporator.

5. A flow-through tubular steam generator according to Claim 4 which comprises an engine arranged to receive superheated steam from the superheater, a valve controlling the admission of steam to the engine, and a device responsive to the temperature of the superheated steam arranged to actuate the valve.

6. A now-through tubular steam generator according to claim 4 which comprises an engine, means for supplying the engine with superheated steam from the superheater, a conduit for discharging steam from the engine into the heat exchanger and in heat exchange relation to the liquid passed into the heat exchanger from the first evaporator, a by-pass conduit for passing steam from the superheater to the heat exchanger, a valve arranged to control the supply of superheated steam to the engine, a second valve arranged to control the ow of steam through the by-passed, and means responsive to the temperature of the superheated steam for controlling the action of the said valves.

7. A flow-through tubular steam generator according to claim 4 in which the evaporator, the rst separator, the re-evaporator, the second separator and the superheater are in tubular series system comprising an engine arranged to receive superheated steam from the superheatery the heat exchanger being arranged to receive steam discharged from the engine` a pump and feed water tank, and a preheater, the liquid discharged from the second separator being passed into the feed tank, a valve arranged to control the passing of superheated steam into the engine, a valve-controlled by-pass for passing steam from the superheater around the engine to the heat exchanger, and a device responsive to the temperature of the superheated steam for controlling the action of the said valves.

VIKTOR JUZI.

CERTIFICATE or CORRECTION.

Patent No. 2,521,590. June 8, 19M.

VKTOR JUZI It is hereby certified that error appears in the printed specification of the above numbered patent requiring Correction as follows: Page l, first column, line 9, strike out the Words "being connected to and arranged to" and insert instead --of each separator has a regulating; line lO, strike out the word --common--g and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this lOth day of August, A. D. l9lp5.

l Henry Van Arsdale, (Seal) Acting Commissioner of Patents.