US2271886A - Steam power plant employing steam generators of the flow-through type - Google Patents

Description

v. .JUZI

Feb. 3, 1942.

STEAM POWER PLANT EMPLOYING STEAM GENERATORS OF THE FLOW-THROUGH TYPE 2 shecs sheet 1 Filed Feb. 10, 1939 INVENTOR V/KTO/f .7027

BY W Um, [7m Hum ATTORNEYS Feb. 3, 1942. v. JUZI 2,271,886

STEAM POWER PLANT EMPLOYING STEAM GENERATORS OF THE FLOW-THROUGH TYPE V Filed Feb. 10, 1959 2 Sheets-Sheet 2 95 INVENTOR V/Kfdfi 2702/ MDaMf/anmlMM ATTORN EY5 Patented Feb. 3, 1942 STEAM POWER PLANT EMPLOYING STEAM GENERATORS OF THE FLOW-THROUGH TYPE Viktor Juzi, Winterthur, Switzerland, assignor to Sulzer Freres Societe Anonyme, Winterthur,

Switzerland Application February 10, 1939, Serial No. 255,580

In Switzerland February 11, 1938 v 8 Claims.

This invention relates to steam power plants employing steam generators of the flow-through type in which steam, after flowing through one part of a power turbine, flows through a re-superheater heated by furnace flue gases.

In a steam power plant of the above type according to the present invention a valve-controlled by-pass pipe is provided between the tube system of the steam generator and the re-superheater so as to enable the re-superheater to be used, at least during the heating up of the steam generator as an extension of the tube system of the generator.

In addition means may be provided for. connecting the re-superheater to atank or condenser by; a valve-controlled discharge pipe. It is also advisable to provide in the steam pipe leading from the steam generator to the power turbine a valve -which'is influenced by the pressure or the temperature of the steam. The valve controlling the discharge pipe from the re-superheater to the tank or condenser may also be influenced by the temperature or pressure of the steam while a valve influenced by the temperature or pressure of the steam may be provided in the pipe leading fromthe re-superheater'to the steam consumption apparatus deriving steam therefrom.

Fig. 1 is a diagrammatic illustration of a steam plant embodying the invention;

Fig. 2 is a fragmentary view on an enlarged scale of apparatus illustrated in Fig. 1, and

Fig. 3 is an illustration of a modified form of a part of the apparatus of Fig. 1.

In the construction illustrated in-Fig. 1, the power plant comprises a steam generator of the flow-through type the tube system I of which is supplied with water by a feed pump 2. During normal operation superheated steam flows from the tube system I through a pipe 3 into the high pressure part 4 of a steam turbine and thence through a pipe 5-into a re-superheater 6 heated by the flue gases from the furnace. The steam- I3 which is influenced through a pipe I4 by the pressure in the pipe 3.

The outlet side of the re-superheater 6 is connected by a disohargepipe l5 controlled by a valve I6 to the tank IO'the valve I6 being controlled by a servomotor 25 influenced through a pipe I! in accordance with the pressure in the,

pipe I.

In the steam pipe, 3 is arranged a valve I8 controlled by a servomotor I9 influenced in accordance with the pressure of the steam in the pipe 3 and also influenced in accordance with the temjpperature to which the temperature-responsive device T1 is subjected.

Finally, there is arranged in the pipe I leading from the re-superheater to the lowpressure part temperature-responsive device T2 is subjected;

The temperature-responsive devices T1 and T2 are connected to and actuate valve pistons 50- and 501 in the devicesZI and 24 respectively. a

The operation of the apparatus is as follows. During the heating up of the steam generator the two valves I8 and 221 are maintained closed by the temperature-responsive devices T1 and T2 controlling the devices 2| and 24 respectively. The WOIkil'lg medium cannot therefore pass either-from the steam generator I to the high pressure part 4 of the turbine or from the resuperheater 6 to the low pressure part 4 of the turbine. The feed pump 2 which supplies a continuous stream of liquid to the generator I, however, then produces such a high pressure that the valves I2 and [Bare opened by the servomotors I3 and 25. thus circulate from the feed pump 2 through the tube system I of the generator, thence through the pipe II and valve I2 to the re-superheater 6 from which it passes through the pipes I and I5 into the tank I0. As soon as the steam generator I has been heated to a suflicient temperature, however, and steam of an appropriate temperature is thus being generated; the valves I 8 and-221 are opened through the influence of the temperature-responsive devices T1 and T2 so that the steam can then flow through the pipe 3 into the high pressure part 4 of the turbine and thence through the pipe 5 into the re-superheater 6 and finally through the pipe 1 'into the low pressure part 41 of the turbine. This results in a reduction of pressure which causes the servomotors I3 and 25 to close the valves I2 and I6 so that the plant is put into condition for normal working.

The values at which the individual pressure- The working medium can ilarly the temperature at which the valves I8 and 221 are maintained closed can be set during the heating up period and sometimes also during normal working to operate at a lower value than for instance under full load conditions.

The control apparatus 2I, 24, 30, 32, 35, 31,

40, 43 as well as the servomotors I3, I9, 23,

receive operating oil fed from one or more oil.

pressure systems 4! which for the sake of simplicity are not completely shown on the drawings. through the pipe 48,

I The pressure responsive device is provided with. a piston valve 53 which is connectedto a pressure plunger 54. The pressure plunger. is under the influence of the pressure in pipe 3. With rising pressure the pressure plunger and the control valve are moved upwards. From pipe 41 oil under pressure then flows in, so that the pressure in pipe 3I rises. With falling pressure in pipe 3 the control valve and the pressure plunger are forceddownwards. From pipe 3| oil can flow away through pipe 48- until the reduced control pressure corresponds to the reducedsteam pressure. in pipe 3. By means of a. hand-operated adjusting device 55 a spring 55 can be given more or less tension. When increasing the tension of. the spring, the control oilv pressures in pipe 3I corresponding to. the steam pressures canbe decreased, when decreasing the tension of the spring they are increased. Consequently it. can be seen'that the control pressures in pipe 3| rises or fall respectively with the steam pressures in pipe 3, and that for setting to the desired figure, the control pressures corresponding to the steam pressures can be adjusted variously as desired by means ofv the handoperated adjusting device 55.

Temperature responsive device 2| has a piston valve 50 influenced by the temperature-responsive device T1 which, as illustrated, is a loop 5I caused to change in length by variation in temperature, such changes being transmitted through spring 52. An increase in temperature causes loop 5I to lengthen, so that spring 52. is

given more tension and piston valve 50 'is pressed.

downwards. Inv this way oil under pressure can pass from pipe 41 through the openings in piston valve into pipe 22. continues to rise until the piston valve is raised again against the action of spring 52 until no more pressure medium can issue from pipe 41. When the temperature falls, loop 5| shortens and the tension in spring 52 is decreased. In this way piston 50 can be raised so that pressure medium flows from pipe 22 into pipe 48 until the reduced pressure corresponds again to the reduced temperature. The result consequently is that when temperature is rising the pressure in control pipe 22 rises and when the temperature is falling the pressure also falls.

The variable control-oil pressures in pipe 3 I' influence control valves 32 and 40 in such a way' that they are more strongly raised against the springs 51 or 58 when pressure is rising than when pressure is falling. Consequently with ris- The outlet oil passes into a return system.

The pressure in pipe 22.

ing control-oil pressure or increasing steam pressure in pipe 3, it is possible for oil to pass from the pressure oil system 41 into the control pipes 59 or 63. On the other hand oil flows out of pipes 59 or 63 to the return system 48 if the control-oil pressure or the steam pressure in pipe 3 falls.

Piston valve 10 is loaded on the lower piston face 'II by the control pressure in pipe 22 and on the upper side by the spring I2. Spring I2 is of such dimensions that under its influence the piston valve remains in its upper position during normal service, so that between pipe 60 and pipe 42 there-is a permanent connection.

The adding device 33 has a piston valve BI that is influenced on, the annular surface 62 by the. control.v pressure of pipe 22, on the piston face 63 through the pressure in space 64, and from above through spring 65. The piston valve in normal service remains so far down that a constant connection is maintained between pipes 53 and 34. Only when the control pressure in pipe 22 has exceeded a certain figure and piston valve 6| is consequently raised, is itpossible for fresh oil to pass into the space 64 through space 56 and groove 61. In this way piston valve BI is pressed into its uppermost position, Where it remains. Between pipes 41 and 34 a permanent connection is then made. be pressed down again into its bottom position only by hand by means of .the press knob 68, and then the pressure medium in space 64 flows through passage 69 to return pipe 48.

Servomotors I3 and I9 have stepped, pistons 13 and I4 respectively which are influencedon the annular surfaces I5 and IE respectively. by pressure from pipe 4'! and on the piston faces 1! and I8 respectively by pressure from the control. pipes 34' and 42. respectively. The pistons can be raised by hand by the adjusting devices I9 and respectively.

Theregulating device works under normal conditions as follows:

If the steam pressure in pipe 3 rises above the figure to which it is set, the control pressure in pipe 3| also rises. two springs 51 and 58v are chosen in such a way that piston valve 40 is raised first. In this way oil under pressure from pipe 41 can pass below servomotor piston I4 through pipes 60 and 42 and the cone of valve I8 is raised, so that a greater quantity of steam canfiow through pipe 3 until the pressure has again returned to the figure to which it was set.

If the desired figure however cannot be reached even when the valve I8. is fully open, or if the. pressure in pipe 3 still further increases, piston.

valve 32 is also raised far enough so that oil under pressure from pipe 4! can pass below servomotor piston 13 through pipes 59 and 34. In this Way the cone of valve I2 is raised so that steam can flow from pipe 3 through by-pass piping II until the "pressure has again become balanced.

If the pressure in pipe 3 falls, in consequence of the falling control pressure the control valve 32 will first of all be forced down. again by spring 5'! until servomotor I3 is connected to return pipe 48 through pipes 34 and 59. The servomotor piston then falls downwards and decreases the effective cross-section of valve I2 until the pressure in pipe 3 has again risen to the figure desired.

If valve I2 is closed without the desired pressure being reached, control'valve 40 also begins The piston valve can' The strengths. of the.

to fall, so that a connection is also established between servomotor I9 and return pipe 48 through pipes 42 and 48. Through the lowering of servomotor piston M the effective cross-section of valve I8 is decreased, and continues to decrease until the desired pressure is reached in pipe 3.

If conditions are abnormal, i. e. if the temperature of the steam passing through pipe 3 is too high or too low, the impulse transmitter 2! also takes part in the regulating operation.

Assuming that the temperature is too high, the control pressure in pipe 22 becomes high, raises piston valve BI and establishes a permanent connection between feed pipe 41 and pipe 34. Valve I2 is thereby fully opened, so that all steam can flow out of pipe 3. The pressure in pipe 3 will then at once fall, whereby the control-oil pressure in pipe 3| also falls and servomotor I9 is connected through pipes 42 and 60 to return pipe 48. The result consequently is that when the temperature is too high, valve I2 is opened fully and valve I8 is completely closed, until knob 68 is again pressed down by hand after normal temperature has been obtained.

If the temperature is too low, the control-oil pressure in pipe 22 will become low, so that piston Ill falls downwards, and thus a permanent connection is established between servomotor I9 and return pipe 68 over pipe 42. Valve I8 is then closed at once and the pressure in pipe 3 begins to rise. In this way valve I2 is raised, so that the desired pressure in pipe 3 is again restored by steam flowing from pipe 3 through pipe I l.

After the temperature in pipe 3 has been raised again to its normal value, valve II is raised, so that valve I8 is again normally regulated through the pressure, and steam can flow away through ipe 3.

It will be found convenient to fit in pipe II a tank 8| with a water space, so that the steam flowing away from pipe 3 through pipe II when the temperature is too high is cooled to the saturated steam temperature before it reaches the re-superheater 6.

Fig. 3 shows a modification in which the bypass conduit I connecting the re-superheater to the feed water system is connected directly to the condenser 3. The steam is then condensed in the condenser and conveyed by the pump 93 into the feed water tank Iii.

I claim:

1. A steam power plant which comprises a flow-through tubular steam generator, a power turbine having at least one high pressure part and one low pressure part, a re-superheater connected at one end by a pipe to the high pressure part and at the other end by a tube to the low pressure part, a tube valve in the tube, a delivery pipe connecting the generator to th high pressure part, a delivery valve in the delivery pipe, a bypass pipe connecting the delivery pipe on the generator side of the delivery valve to the pipe connecting the re-superheater to the high pressure part, a by-pass valve in the by-pass pipe, a device responsive to the temperature of the steam in the delivery pipe, a device responsive to the pressure of the steam in the delivery pipe, a tank for receiving condensate from the low pressure part of the power turbine, a feed water pump arranged to pump water from the tank to the generator, a discharge pipe connecting the tube to the tank, a discharge valve in the discharge pipe, a device responsive to the temperature of steam in the tube, a device responsive to the pressure of the steam in the tube, means operatively interconnecting the devic responsive to temperature and the device responsive to pressure in the delivery pipe with the by-pass valve and the delivery valve, and other means operatively interconnecting the device responsive to temperature and the device responsive to pressure in the tube with the tube valve and the discharge valve, whereby the said valves are opened or closed selectively to maintain a desired operating pressure in the plant.

2. A steam plant according to claim 1 in which means are provided to set the devices to operate the valves in a predetermined order depending upon steam pressure and temperature.

3. A steam plant according to claim 1 which comprises a separate servomotor for operating the discharge valve and the tube valve and an operatively interconnected fluid system for operating the servomotors under impulses received from the devices actuated by the temperature and the pressure of the steam in the tube.

4. A steam plant according to claim 1 which comprises a condenser, and pipe for passing steam from the outlet side of the low pressure part to the condenser and from the condenser to the intake side of the steam generator.

5. A steam plant according to claim 1 which comprises a condenser, a feed water tank, pipe connecting the outlet side of the low pressure part with the condenser and the condenser with the feed water tank, said discharge pipe being connected to the feed Water tank, and a pipe provided with pumping means connecting the feed water tank with the intake side of the steam generator.

6. A steam plant according to claim 1 which comprises a servomotor connected to and arranged to operate the delivery valve, an adding device connected to and arranged to control the operation of the servomotor, said adding device being connected to and actuated by the device responsive to the temperature of the steam in the delivery pipe and also connected to and actuated by the device responsive to the pressure of the steam in the delivery pipe.

7. A steam plant according to claim 1 which comprises a servomotor connected to and arranged to operate the tube valve, an adding device connected to and arranged to control the operation of the servomotor, said adding device being connected to and actuated by the device responsive to the temperature of the steam in the tube and also connected'to and actuated by the device responsive to the pressure of the steam in the tube.

8. A steam plant according to claim 1 which comprises a servomotor connected to and arranged to operate the delivery valve, an adding device connected to and arranged to control the operation of the servomotor, said adding device being connected to and actuated by the device responsive to the temperature of the steam in the delivery pipe and also connected to and actuated by the device responsive to the pressure of the steam in the delivery pipe, a second servomotor connected to and arranged to operate the tube valve, another adding device connected to and arranged to control the operation of the second servomotor, said other adding device being connected to and actuated by the device responsive tothe temperature of the steam in the tube and also connected to and actuated by the device responsive to the pressure of the steam in the tube.

VIKTOR JUZI.

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