US2263687A - Vapor generator or boiler - Google Patents

Description

Nov. z5, 1941. G, WNSCH l 2,263,687

VAPOR GENERATOR OR BOILER Filed May e, 193e 2 sheeis-sheet 1 /nvenon' Guido Wnsch,

f/ ma,

Nov. 25, 1941. v

G. WNSCH VAPOR GENERATOR 0R BOILER Filed May e, 1959 2 Sheets-Sheet 2 imanes.iat-;22s,4 1941 l UNITED STATES vPlrra-N11* OFFICE VAPOR 'GENERATOR 0B BOILER -4 Guidofwnsch; Berlin-Wannsee' Germany, as- I signor to Askana-Werke A. G., a corporation orGermany .Application This invention rentes u', that generator or boiler 'which includes a water reser. voir at o'r 'towards the end -of the vaporising section.v y

The operation or'foncefthrougW-or through flow -vapor generators or boilers Aoi. the usualconstruction, introducesv the diiiiculty that in practice itis not possible" so to balance the quantity of feed water t thel heating ofthe furnace that lth'esteam producedhas the desired .tem-L 'p erature.v Every small variation in thefstoking -ofthe furnace, 'everyiluctuation in the steam pressure and every' change in the feedfpressure destroys the .equilibrium of the operation, and

value,'and the consequent increase in tempera- .ture of the steam, raise the resistance to iiow in the steam section of the boiler thus reducing May s,"1ss9;ser1a1 No.. 272,249 Germany May 71938 1s claims. loi. 12a-451)- kind of vaporA 'does not affect the water content of the steam at the endof the vaporization section and thus the eflective-lengtlfi of the superheater of the boiler. Y

These defects are to some degree removed byv the :provision of a water reservoir'in theboiler o r generator at or towards the end'oi the Vaporizing section, as has previously been done.

In some of the boilers of this kind, however,

Water -level regulators were provided for controlling the feed such that the level of the water in the-'reservoir remained constant, the excess conserved water ilowing away or .being returned to the feed pump.

In another prior propbsal the inventor caused the varying ofthe water ylevel in the reservoir by a steam-temperature-responsive control of a discharge conduit and in such a way that a. greater the amount of feed water which can be admitted.

'This produces a still further increase in the steam temperature, so that these usual generators or vboilers are liable to a certain amount of-in stability. l

In these .earlier generators or boilers an even greater drawback is met with, viz. that the conf trolof the quantity of feed water, which is for example effected by a temperature and/,or load regulator. can only be effected with a large degree f of lag.'-

unexplained, it is'in-practice-impossible to control the-operating conditions in the boilermerely by. regulating the supply of-ieexiwater, as

,theoretically shouldbe possible.y ,When 'varia-Y tions occur in the load, the, lag in theeiect produced by the increase ofleed water results in an undesirable displacement of the zone of conversion in the boiler, i. e. avariation in the. length of the .superheater and a uctuation in vthe steam temperature. On the other hand` i! regulation, which is' theoreticaliyconceivable and is regarded, as a particular advantage ci once. throughtboilers, practically useless. Experience has indicated thata regulation ofl the vfeed water In view of filling-up or congestion processes which take place in the vaporizing section of the boiler, and which' are still partly'v or smaller portion of the. collected water was carried away by the steam and thus regulated the temperature of the latter. 'This form of regulationof the steam temperature has the drawback that the amount of water carried off` by the steamis dependent on vthe water level in the container. However, this waterlevel only' varies comparatively slowly when the discharge conduit is regulated, and the smaller the\degree of excess feedthe slower the change in the water level. In the case of the boilers without an excessl feed, this useless.

Thus the-quantityvof conserved water which` is carried oif by the steam for cooling the latterv is only eii'ective a considera-ble time''after the steam temperature has altered, this lapse of time beingl still greater as the. excess feed to th boiler-iss'maller.

Inaccordance with this invention there is provided a through flow boiler including a tubudischarge conduit Ileading into the said tubular vaporizing system of' the boiler, water 'discharge regulating means for said discharge conduit, and steam temperature sensitive means disposed so as to be -respon'sive't'o the temperature of the steam produced by said vaporizing section of the boiler and adapted tocontrol the regulation of .the said water dischargedregulating means.

'Thus the water in the reservoir is not, in this invention, carried of! bythe steam in an amount coi-related to the temperature-dependent water level, .as in the aforesaid prior proposal, but is method otregulation is entirely complexity .added directly to the `steam through the tem'- temperatureimpulse without any time delay and v independently of the degree .of over-feed. Thus the invention is also applicable for use with boilers which only operate with a small excess feed sumcient for navigation purposes, and in boilers of this nature it is only by using4 the present invention' that it is possible to obtain a regulation of the steam temperature which is independent of the above-mentioned "filling-up" phenomena.

A further advantageis secured by using the present invention. Once-through boilers normally have avery small feed capacity which, in the main, is determined bythe quantity of lboiling water in relation to the steam produced. per unit time. The additional' quantity lof water present in the reservoir, which for example is 1/2% of' the output per hour ensures a suiilcient feed capacity for the majority of purposes.

The conserved water can be added to the steam by arranging that the level of the water in the reservoir is above the part'at which the discharge conduit opens into the part of -theboiler beyond the reservoir. Alternatively a drop in flow pressure which is present (and which may be artificially increased) between the reservoir and the opening of ther discharge conduit into the boiler can be utilized. 'I'his latter arrangement has the advantage that a quantity o'f water proportional to the quantity of steam owing is automatically withdrawn by suction from the discharge conduit.

.The reserve watermay be supplied to the boiler tubular system in a steam cooler of suitable constructiom'but preferably one in which the separation of water is effected by a centrifugal action. This enables salts to be deposited from ,separator 2,

The boiler is continued beyond the water separator 2 in the form of a tube 8 of looped shape,

the lower bend of thi loop being located at a lower level than the ttom of the separator 2D This tube 8 includes a Venturi nozzle 9, and a discharge pipe I0, connected to the bottom of the communicates with this Venturi nozzle.

A valve II inserted in the line I0 controls the flow of liquid in the latter, and this valve II is adapted to be adjusted by the piston of aservomotor I2. -The two sides of this piston are con- In these drawings, I designates generally the t vaporization section of a once-through or push throng boiler or vapor generator and this section of the boiler is connected to a reservoir in the form of a centrifugal water separator 2.

- ,'In the embodiment of the invention illustrated in Figure 1, the vaporizing section of the boiler is fed with water through a feed conduit 3 containing a main feed water valve 4. A second feed water valve 5 is arranged in shunt with the valve 4, and the latter is controlled by a. servoinotor 4' which isgoperated by a feed water regulator of conventional form,` the latter being omitted from the drawings to avoid unnecessary Arranged in the separator! isa float l which is niounted on an arm pivotable about the point 8, v and this float lis adapted to operate the valve l through a suitable mechanical connection, e. g.

5'. Alternatively .the valve i-could, of course, be .operatedby a water level regulator which is de- `source controlling the valve.

nected by conduits Il-'and I4' to a temperature regulator I3 of known construction. This regulator includes a thermostatic member I5 which is so arranged as to be subjected to the heat of steam leaving the boiler through a steam consumption line I6, whereby the member I5 enables the temperature of thesteam as'it leaves the.

boiler to be estimated.

Finally, a superheated section of the boiler lies between the loop 8 and the steam line I6,

The boiler which is described above with reference to Figure l ofthe accompanying drawings functions in the'following manner.

A part of the feed water required by the boiler passes thereto through the valve 5 in the shunt line. The control of the valve 5 exerted by the float 'I vin accordance with thev water level in the separator 2 is such that this levelv remains the same with the water at a. predetermined height.

A certain amount of water continually escapes from the separator 2, through the discharge pipe .I0 and the valve II-, into the tube 8 and thus affects the amount of water in the steam, i. e. the eiiective-length of the superheater section I1. As soonl as the steam flowing through the superheater I'I becomes too hot, the temperature yregulator I3 opens the valve II and allows an increased quantity of water to flow into the tube 8. In the result, the water level falls in the separator 2 and the iioat I consequently causes a corre- ,spondinglyincreased opening of the-valve 5.

Since the separator 2 contains aconsiderable volume of water, it is of no disadvantage if the effect of the extra supply of water to which the valve 5 is set is not apparent in the separator 2 until some time has elapsed. The reserve of water leaving the separator 2, which reserve determines the water content of the steam fiowing through the loop 8, is on the contrary immediately available, and in view of the comparatively small size of the superheater section I1, the steam temtively passed into this loop, even if only quite a small quantity of steam is present therein.

The Venturi nozzle 9 produces a fall in the flow pressure in the pipe I0 which is greater according as the vquantity of steam passing through the tube 8 is greater.

Referring now to Figure 2, the vaporizer I is here supplied with, water through a valve I8 which is under the dual control of a servomotor I 8' of a feed water regulator (not shown), and a lever system I9 which is operatively vconnected to the iioat l in the water separator 2. This dual control is eifected through a known form of sumi amasar.

mation leversystem denoted l2li in thedrawings.4

In contradistinction to the arrangement illus- 'trated in Figure 1, the discharge pipe connected- -to the underside of the 'separator 2 herecommunicates with a steam cooler 2| which is connected up between two superheater stages I'| and II/'in the steam line. The cooler 2|.-,com-

prises a spherical vessel into which a rectilinear extension of thev superheater I'I; openstangentially. The pipe I is also tangential to the condenser 2| adjacent its point of connection thereto.v

vBy this means ari annular circulation oi water isset upin the condenser 2 I, and the steam from the superheater I1 has to pass. through'this be- /fore it can enter the superheater stage II'I'. This centrifugal action has. therefore, the result 1,25

only dry steamf passes to the'superheater I1'.

The residual water which accumulates in the cooler 2|, and-which will of course containvarious salts, can be drained. off, fromtime intime, through a valve-controlled sludge pipe `22.

As in the first embodiment described, a valve arranged in the, pipe In and isteria-oued through aservomotor I2 by a temperature regulator I3. Y

Now neglecting the diilerence in level between the water separator 2 and the steam cooler 2|, which difference can conveniently be made zero in constructing the plant, the'pressur'e in the \cooler 2|, is less'than in the separator 2 because l of the fact that the superheater which sets up a certain amount of resistance to the flow of the steam, lies between them. 'Ihus the fall in pressure in the superheaterll also affects the valve II through the pipe Ill.. -This fall in pressure is also however, a measure of thequantity of `steam flowing through the superheater I1 and if the quantity of steam is doubled, a four-fold drop in pressure occurs in the superheater I'I. Thus theV differential pressure eifective at thefvalve I I rises to the sameextent, so that a double quantity of -water entersthe condenser 2| if the valve II is not shifted.' 'I'hus the steam will automatically withdraw av proportionate amount of cooling water through the unadjusted valve without any time lag. Consequently, the temperature regulator I3 has only' to compensate minor .and

slowly-recovering fluctuations when variations occur in the load. 1

Two further valves 23 and 24 are controlled by the float 1 in the water separator, 2. The valve 23 is located in an auxiliary discharge 'conduit I0' Vconnectingy the discharge pipe Il) to asuitable pressure stage in a feed pump 25 supplying water-through the conduit I to the boiler. The valve 24 is located .in an inlet conduit 28 which is branched oil?- the water feed conduit. I

v is no longer required.

that a means iorprodncing the injection pressure What I claim is:

' 1.- A v through iiow. boiler including a tubular vaporizing system,. a Water reservoir arranged in the said vaporizing system, means -for maintainof the steam .produced by saidvaporizing sectionof the boiler and adapted to control the regulation of the said water discharge lregulating means.' 2. A boiler accordingto .V claim 1 wherein the said Water separatingsteamcooler comprises a centrifugal separator.

3; A push-through boiler comprising a. tubular vaporizing system, .a tubular superheatingsys-v tem, a water reservoir betweenand connecting.,

togetherthe vapori'zing and superheating lsystems, conduit means for discharging water from the said reservoir into the *tubular system of? the boiler beyond the reservoir, valve means for regu-V 'latingl the discharge of l water by said conduit means, a steam temperature responsive deviice adapted to control said discharge regulating valve.

' and means for maintaining the level of the Water in the said reservoir substantially constant.

4.` A through iiow boiler comprising a tubular vaporiaing system, a vtubular superheating system, a Water reservoir betweenl and Iconnecting together the vaporizing and superheating sysin iront ofthe valve I8 and opens into the upper portion of' the separator 2. Immediately the water level in the separator 2 becomes too high, the oat 1 opens the valve 23 and permits water to flow back through conduit I0 to the feed pump 25. On the otherv hand, if the water level fallsv too far, the valve 24 is automatically opened and the reserve of water in the separator 2 is immediately supplemented via the conduit 2B.

The valves 23, 24 and I8 can of course, be

otherwise controlled, lfor example by means oi.

water level regulator -with'a'n auxiliary source of power. A water level-diilerential pressure system can be used for controlling the water level regulator.

An evaporator cooler of known construction ein be used 1n place or the comer zi wan its centrifugal separating construction. The use of 4a temsfconduit means for discharging water from the said reservoir in to the tubular system of the boiler beyondthe reservoir, valve means for reguyIating'the discharge of water bysaid conduit means; a steam temperature responsive device adapted to control. said discharge regulating valve, a feed water regulating valve associated with the feed water supply system, and means responsive to the level of water in the said reservoir and adapted to effect a variation in said feed Water regulating-valve on a variation of --said reservoir water level occuring. A

5. Al through flow boiler comprising a tubular vaporizing system, a tubular superheating system, a Water reservoir into which the said tubular vaporizing system discharges, an auxiliary feed water supply line in shunt with the main feed water supply line, a main feed water regulating valve in the main feedV line, an auxiliary lfeed lwater regulating valve inthe said auxiliary line,

feed water regulator means controlling the ,said

main ieed water regulating valve, afloat in said reservoir adapted to control said auxiliary feedv water regulating valve in accordance with the level oi the water in the reservoir. a looped steamtube leading vfrom the steam space of fthe said reservoir to the said superheating tubular system, a water discharge conduit leading from the'- said reservoir to the said looped steam tube and communicating with the latter, the said looped steam tube having its lower bend below the level of the bottom of the said reservoir, and the said water discharge conduit entering the looped steam tube at a level lower than that at which it leaves the said reservoir, 'means adjacent the entry of the said'waibr discharge'conduit into ,A y 3 condenser instead off'the erstwhile usual injectornozzles for the cooling water has the advantage the looped steam pipe to ensure a fall in steam ing valve in said water discharge conduit, means for operating this valve, and a temperature sensitive device disposed soas to be responsive to the temperature of steam at thev end of the tubular superheating system of the boiler and adapted to control the said Water discharge regulating valve operating means.

6. A through flow steam generator comprising a tubular vaporlzing system, a tubularsuperheat- 7ing system, a water reservoir into which the said tubular vaporlzing system discharges, an auxillary feed water supply line in shunt with the main feed Water supply line, a main feed water regulating valve in the main feed line, an auxiliary feed water regulating valve in the said auxiliary line, feed water'regulator means controlling the said main. feed Water regulating valve, a float in said reservoir adapted to control said auxiliary feed water regulating valve in accordance with the level of the water in the reservoir, a steam tube leading from the steam space of the said reservoir to the said superheating ing from the said reservoir to the said steam tube and communicating with the latter, vnieans adjacent the entry of the said water discharge conduit into the said steam tube to ensure a -fall in steam pressureat this position below the pressure within the said reservoir, a water discharge regulating valve in said water discharge conduit, means for voperating this valve, and a temperature sensitive device disposed so as to be responsive to the temperature of steam at the end of the tubular superheating system of the boiler and adapted to control the said water discharge regulating valve operating means.

7. Apparatus for controlling the operation of a vapor generator having a once-through vapor passage receiving liquid at one end'and delivering vapor at the other end, comprising in combination a liquid separator arranged in the zone of evaporation vof said passage, means for maintaining the liquid level in said separator substantially constant, a liquid discharge conduit leading from a point below ,the liquid ,level in tubular system, a water discharge conduit leadrator so as to cause the separater'. liquid to be drawn through said liquid discharge conduit.

12. Apparatus for controlling the operation of a Napor' generator having a once-through fluid passage receiving liquid at one end and deliverving vapor at the other end comprising in comliquid discharge conduit leading from a point below the liquid level in said separator to the vapor part of said passage, liquid discharge controlling means 'for said discharge conduit and means responsive to the temperature ofthe vapor in said vapor part of said passage for actuating said liquid discharge controlling means.

13. Apparatus for controlling the operation of a vapor generator having a once-through fluid passage receiving liquid at one end and delivering vapor at the other end comprising in combination a liquid separator arranged in the evaporation zone of said passage, a liquid discharge conduit leading from a point below the liquid level of' said separator to the vapor part of said passage, liquid discharge controlling means for said discharge conduit, means responsive to the temperature of, the vapor in the vapor part of saidjpassage for actuating said liquid discharge controlling means,` first liquid supply control 14. Apparatus as set forth in claim 13 includv ing additional means for automatically supplying make-up liquid directlyl to said separator if the liquid level therein 'falls below a predetering additional means for automatically dischargsaid separator to the vapor part of said passage,

'liquid discharge controllingmeans for said discharge conduit and means responsive to the temperature of the vapor in the vapor part vof said passage for actuating said liquid discharge controlling means.

8. Apparatus as set forth in claim 7 in which the mouth of saidliquid discharge conduit is disposed at the 'same or at a lower level than the mean liquid level in said separator.

9. Apparatus as setforth in claim 7 in which the m'outhof said liquid' discharge conduit is disposed at a point of the vapor part of said passage at which the pressure due to the pressure drop in said passage is smaller than the pressure in said separator.

. 10. Apparatus as set forth in claim 7 in which the mouth of said liquid discharge conduit `is arranged at a pressure reducing device disposed in the vapor part of said passage beyond said separator so as to cause the separated liquid to be drawn through said liquid discharge conduit.

ing liquid through an additional liquid discharge conduit from said separator if the liquid level therein rises above a predetermined value,

16. Apparatus as sei-,forth in claim 13 including a float in said separator', a liquid supply control valve actuated in joint response to the movement of said float and to a liquid supply regula'tor, an excess liquid discharge 'conduit connecting said separator to the liquid supply control means, a control valve in said excess conduit connected to be actuated by said float so as to be opened if the liquid level rises above a predetermined value, an auxiliary liquid supply conduit leading to said separator from said liquid supplymeans, and a valve in said auxiliary conduit connected to be actuated by said float so as to be opened in accordance with the fall of the liquid level in said separator.

17. A vapor generator of the forced passage type having a once-through iiuld passage receiving liquid at one end and delivering vapor at the other end, said passage including a vapor generating section and a superheating section, said latter section consisting of two successive parts, a rst liquid separator arranged between and connecting said vapor generating section and said superheating section, a second .liquid separator arranged betweenand connecting the A 2,263,687 two parts of the 'superheating section, a liquid discharge conduit leading from a point in said first separator below the liquid level therein to said second separator, liquid discharge controlling means for controlling the liquid flow in said discharge conduit, and means responsive to the temperature of the superheated vapor at the end of the superheater section for actuating said liquid discharge controlling means.

18. Ayapor generator as set forth in claim 17 including in addition a main supply conduit for supplying liquid to said",y vapor generating section, an excess liquid discharge conduit connecting said flrst separator to said supply conduit.

float means in said rst separator, valve means for controlling the ow of liquid in said discharge conduit Aand connected to4 be actuated by said oat means so as to lbe opened if the liquid level in said separotor rises above a predetermined value, an `auxiliary liquid supply conduit leading to said rst separator from said main conduit and a valve for controlling the iiow of liquid in said auxiliary conduit operatively connected to be controlled by said iloat means so as to be opened in accordance with the fall of liquid level in said separator.v

GUIDO WNSCH.

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