US1777633A - Feed-water-regulating system - Google Patents

Description

Oct. 7, 1930. J. M. BARRETT ,777, 33

FEED WATER REGULAT ING SYSTEM Filed May 4, 1925 5 Sheets-Sheet 1 gmxe nfov Oct. 7, 1930. Y J. M. BARRETT 1,777,633

I FEED WATER REGULATING SYSTEM Filed May 4, 1925 3 Sheets-Sheet 2 FIG.'-ZI ywmczw (1110: near 930- J. M. BARRETT 7 1,777,633

FEED WATER REGULA TI'NG SYSTEM Filed May 4', 1925 s Sheets-Sheet a gwuanloz Fla-Z1 MGM a m wu m nw attorney! Patented Oct. 7, 1930 UNITED STATES PATENT emu:

JOSEPH M.,BARRETT, OF FOSTORIA, OHIO, ASSIGNOR TO THE SWABTWOU'I COMPANY,-

OF CLEVELAND, OHIO, A CORPORATION OF OHIO FEED-WAT'ER-REGOLATING SYSTEM Application filed May 4, 1925. Serial No. 27,785. i

., This invention is concerned with improvements in feed water regulators of the continuously operated type. Such regulators areusually responsive to changesin the water level of the boiler being fed, but changes in the rate of water flow in the feed water line to the boiler are not entirely dependent upon variations in the boiler water level for changes in the feed water pressure over the boiler pressure efl'ects, to a considerable extent, the rate of the feed water flow to the boiler when such devices are used. While the pressure in a feed water line may be maintained at a constant excess relative to the i hoi ler pressure, nevertheless pressure changes in the boiler may continually take place when the steam demand on the boiler varies, for example, when the boiler rating is stepped up or down and such constant feed water excess pressure while being proper for normal rating may be inadequate for heavy over-rating. Hence it is apparent that the rate of feed waterflow to the boiler can not be absolutely controlled by the usual feed water regulator and particularly when the pressure in the feed water line is greatly in excess of the pressure inthe boiler thus causing an unbalanced steam delivery from the a boiler. If the boiler being fed happens to be one of a battery servicing a common steam header, this hoiler'steam delivery will be changed, thus causing variation in the steam pressure in the header, or the line being serviced; all due to the factthatthe proper rate of evapoi. ration of the water in the boiler is lacking as a eonseql'lence of the overfeedin'g of the boiler by the feed water line. Adjusting thefiring or furnace conditions of the boiler will not reach this deficiency as the time element invol ved is shorthut very frequent in the course of a days operation, and the entire balanced boiler en vi ronmcnt is upset, in that, the superheater may accumulate condensate; there is a tendency to decrease the temperature'of centage of gases; a lowering of the feed water temperatm'e, etc. 7 All of theforegoing deficiencies in boiler operation in the modern power. plant may be directly traceable to irregularity of feed water flow to the boiler,

the stack and thus to cause a drop in peer and this irregularity is caused primarily by varying excess feed water line pressures over boiler pressures.

fl he. general object of my invention therefo'i'e, is the provision of a boiler appliance which is directly responsive to pressure conditions in'the boiler for regulating or main-' taining pressure in the feed water line at a constant excess relative to the boiler pressure.

A more specific object of my invention is the provision of a pressure reducin ap paratus for the feed waterline of a boiler to serve as a protective means, for a feed water regulator valve of a ressure generator system controllin the .eed water flow to the boiler and which serves to maintain a constant difi'erence between the pressure in the feed Water line and in the boiler.

Other objects of my invention will hereinafter become apparent from the following description referring to-the accompanying drawings illustrating a preferred form thereof. The essential characteristics are summarized in the claims.

In the drawings, Fig. 1 is a side elevation of a boiler and feed Water system therefor including an electrically driven pump; Fig. 2 is an enlarged view of a feed water pressure regulating apparatus; Fig. 3 is'a crosssectional elevation of the same; Fi 4 is a cross-sectional view taken along the me 44 of Fig. Sand Fig. 5 is an enlarged frag-' in a general way in 'a patent to N. Copley on a feed water regulator, No. 1,193,125 and issued August 1, 1916. Such a mechanism is usually mounted on the boiler to have the pressure generator thereof extend through the plane of the normal waterelevel of the boiler.

The feed water regu ator The heat exchange of the pressure generator of such an appliance is not sufiiciently rapid or efficient-enough to afford refined regulation of the feed water flow of a high pressure modern power plant boiler since no refined water regulatorvalve. In Fig.1, I show the drum 10 of a water tube boiler connected to a header or line 12, and to a source of water supply through a feed water line 13. The feed water line 13 is fed by a pump 15 connected to a suction line 16, the pump being driven by a turbine or motor 17. Connected in the feed Water line is a feed water flow regulating valve 20 of the diaphragm type such as is disclosed in the Copley patent referred to and this diaphragm valve is operated by pressure in a line 21 connected to a pressure generator 22. The pressure generator 22 is disposed to stand or extend through the plane of the normal water level of the boiler drum 10 and to surround a conduit 23 connected to the boiler drum above and below the. Water level thereof. Such a connection may be made to a water column valve 25 above the water level and below the water level to a second water column valve 27. Immediately adjacent the regulating valve 20 I provide a pressure control valve 29 preferably of the diaphragm type which is connected to a lower region of the drum 10 of the boiler by a conduit 30. This valve functions in a manner to be hereinafter described, to maintain aconstant difference between the pressures in the boiler drum and the pressure in the feed water line to the point of passage through the feed water regulatorvalve 20, and as shown in Figs. 2 and 3, is disposed in the feed water line between the valve 20 and the pump 15.

The pressure regulating valve 29 comprises a main valve body 31 having a diaphragm supporting extension 32 attached to a branch thereof, and the upper perimeter of the extension member 32 comprises a bearing or clamping surface for a diaphragm 33.

The nut 45 is'f-ormed to rest in a counterbore 32 of the extension member and thereby limit the downward deflection of the diaphragm and the cap 34 serves to restrict the upward movement of the diaphragm. This diaphragm is acted upon-by the. boiler pressure plus an excess pressure in the form-of an adjusted spring pressure on one side and by an opposing feed water pressure on the other side which is enclosed by a closure or cap member 34 secured to the extension member in any suitable manner preferably with sure exceeds the maximum boiler pressure.

The valve proper may comprise a removable double seat close fitting member 36 to contact or seat upon outlets 37 removably supported by the valve, body partition wall 28. The lower seat portion of the number 36 may be of greater effective area than the upper so that the number 36 is urged downwardly b the feed water pressure, so that the valve Wi l assume an open position in the event of breakage of any of the controlling parts. The valve member 36 may be connected to a diaphragm actuated stem 40 by a hollow nut 42 which engages an enlarged head 43 formed on the lower end of the stem. The upper end of the stem is threaded as indicated at 44 to receive a flanged nut 45 contacting with the under face of the diaphragm 33 and a flanged nut 47 engaging the upper face thereof. A. passageway 49 is formed in the extension member 32 of sufiicient diameter topermit the feed water to pass through the extension member and exert pressureon the underface of the diaphragm 33. A conduit 30 extend: ing from the boiler drum to the valve mech-' anism is connected to the valve through a by-pass valve 50 mounted upon a branch 51 of a spring housing member 59 which encloses an excess-pressure spring 54. member 59 is mounted upon the cap 34 in a leak-proof manner and is of sullicient strength to withstand the greatest pressure which may be exerted at any time within the boiler drum 10. The excess pressure spring 54 is supported between a collar member 56. in engagement with the upper end of the valve stem 40,- and an adjustible collar 58 which is suitably slottedto engage ribs or ways 55 formed on the interior wall of the member 53 and the collar member 58 is in threaded engagement with an exce s pressure adjusting screw 60 which has a shoulder 61 bearing against the upper wall of the spring housing member 53. A packing gland 64 is provided in the upper wall of the spring housing member to closely fit about the screw member shown. 4

I would suggest certain refinements in the pressure valve structure described tending to insure constant and accurate performance and particularly in the body structure of the valve whichsupports and houses the diaphragm. For instance the shape of the inner face of the plate cap 34 may be such that when the pressure in the boiler is unusually low, the major portion of the upper face of the diaphragm'will be supported by the plate and the collar 47 and the contours of these two members may be such that the diaphragm The and valve member. It will be seen that by' under face of the diaphragm under adverse pressure conditions. 7

Also the connection between the stem and the valvemember 36 may be such that the cap nut 42will firmly join the stem and valve member. The enlarged end of the valve Stem may be provided with a key portion 10 to engage in slot 42 formed in the upper threaded end of the valve member 36 to prevent relative turning between the stem changing the members 32 and 34 to support diaphragms of different diameters, a standard product may be manufactured for an extensive range of pressure controls while necessitating only the dimensionalchange of but three of the elements of the mechanism.

I also find that the seating relation between the seats 37 and the, valve member 36 may be of the specific shape shown in Fig. 5 wherein the coniformed seats 36 are shown as having a substantially ring contact on the annular coniform shoulders 37 of the sleeve members. This restricted contact permits the valve members to be urged into a close seating or closing relation under a predominating high pressure in the pump line.

The by-pass valve is provlded with a valve stem 70 which controls a'pas sage 71 extending to the branch passage 72 of the spring housing and this valveflstem 70 may be of the needle type to interrupt fluid pressure between the boiler drum and the spring side or upper side of the diaphragm. A second valve stem 74 is provided in the bypass valve which is adapted to close communication between -a by-pass conduit 73 and the spring housing passageway 72; Thus in normal operating condition, communication between the boiler drum and the spring chamber above the diaphragm is restricted to a small cross section by use of the needle valve. I find this to be a factor on the side of safety, particularly in the event of a fracture of the diaphragm, for this restricted passage would then prevent any harmful flowof feed water to the boiler drum through the diaphragm by wayof the by-pass and at the same time would create a back pressure above the diaphragm which with the aid of the pressure of the spring 54 would keep'the difi'erential valve open until the stem 74 could be moved to open position and the stem moved to closed position. Thus the prevailing pump pressure in the branch passageway 39 of the valve body 31. may be exerted within the spring housing 53 and-consequently en the upper face of the diaphragm. Hence the valve may be rendered inoperative, when desired.

It will be seen. from the foregoing descri tion of this valve mechanism, that since t e position of the valve is ahead of the feed watcr regulator, the desired excess pressure may be obtainedby adjusting the screw 62 to compress the spring 54 whereby there will be exerted on the upper face of the valve and within the spring housing 59, a pressure which is equal to the spring pressure plus the prevailing pressure in the boiler drum 10 and there will be exerted on the underface of the dialihragm and through'the extension member 32, the pump pressure exerted on the feed water in the branch passageway 38, and the valve body 31. When this latter pressure is greatly in excess of'the combined pressures of the prevailing boiler pressure plus the spring pressure, the diaphragm 33 will be deflected upwardly thus carrying the valve members 36 to seating or near seating position relative to the valve slecvcs37. It will thus be seen, that even though the feed water level in the l'oiler is below normal andthe pressure generator 22 has generated sufficient pressure to completely open the feed water flow control valve 20, and if there has been an extreme drop in the boiler pressure very little water will pass through the boiler until the pressure in the boiler increases, whereupon this increase in pressure will cause a downward deflecting of the diaphragm 33 and thus open the pressure regulating valve to permit flow. of feed water through the regulating valve 20 at a pressure which is at the desired excess over the pressure prevailing in the boiler. On the other hand if the water level is sulficiently low to cause the valve 20 to be wide I open and the pressure governor valve is partly-open, the water will be fed to the boiler at the desired excess pressure over the prevailing steam pressure in the boiler. Taking a practical example of boiler operation to illustrate one of the chief advantages to be found in the use of my invention, I will first assume that a power plant having a battery often boilers is operating with a two feed water line, etc., will give approximately a twenty pound excess pressure in the feed water line at the feed water regulator valve. This excess pressure, ofcourse is excess over the two hundred pound boiler header line pressure and not a twenty-pound excess pressureover the actual drum pressure. If there is a two-hundred pound pressure in the header line, then there is. an excess pressure in each of the boilers of about two hundred and five pounds when the boilers are operatin'g at their usual boiler rating. We would then have only an .actual excess feed water pressure of fifteen pounds over the prevailmg drum pressure of the boiler.

Under the foregoing conditions, regula ,tion may be maintained, but if we assume that a condition arises calling for a one hundred per cent increase in the rating of say half of the boilers, there is an additional excess pressure or five pound increase in the aresulting decrease in excess drum pressure over line pressure, then the excess water pressure in the feed line to these low rating op- .erating boilers, would. be about eighteen pounds' In the latter boilers, there would be a resulting increase of feed water flow with the resulting further lowering of their steaming ability and for a short period they would merely function as Water heaters. The water level in the high rating operating boilers would drop due. to the increasing vaporation therein and also due to the lowering of the excess water pressure over the drum pressure.

It will be obvious that if pressure governorsare positioned in each individual feed water line in the respective boilers, that only such pressures will prevail in the feed water line as will have a constant excess relative to the prevailing pressure in the boiler being fed irrespective-of the regulating condition of the feed water regulator being operated by a pressure generator responsive'only to prevailing water level conditions in said boiler. It also will be obvious that a further use of such a governor valve will be found where high excess water pressures are to be carried at pumps, due to small feed water lines- (incidental to high pressure practice) and friction losses in such lines and in the lines on the other-side of the pump, namely economizer i-riction losses, etc. Furthermore it will be apparent that if the high excess pressures are carried at the feed water regulator valve and not reduced before reaching the valve, excess of wear results in the feed water regulator valve members and furthermore the slightest change in feed water regulator valve operation efiects a change in water flow, all out "of roportion to the actual requirements of the moment due to. lngh velocity of the feed-water flow under high excess pressure.

1. In a boiler feed pipe, the combination of a, valve responsive to changes in water level in the boiler, a fluid actuated valve disposed adjacent thereto and res onsi've' to chapges in-pressure dropthroug the first namedfiilve, excess pressure means associated with-the latter valve,.means for thrptsaid cham r whereby the fluid pressure sothat the excess pressure 7 means forces the latter valve open.

2. In a feed water regulating system a boiler, having a feed water pump for exerting pressure in the feed water line in excess of the maximum rated boiler pressure, the combination of a pressure reducing means in the feed water line, comprising a diaphragm actuated valve, a feed Water flow regulating device connected in the feed water line between the boiler and the diaphragm valve, said diaphragm actuated valve being connected in the line whereby the reduced pressure may be exerted upon one side of the diaphragm, a conduit connected to the boiler below the normal water level thereof, a second conduit connected to the feed water line between the pump and said valve, means connecting said conduits to the valve wherefor by either boiler pressure or pump pressure by way of addition to the prevailing boiler' pressure, a predetermined excess pressure.

- 3. In a feed water regulating system for a boiler, having a feed water pump adapted to maintain feed water pr'ilssurein' excess of the maximum boiler press re, the combination of a diaphragm operated pressure reducing valve in the feed water line, a feed water flow regulating device connected in the feed Water" line between the boiler and said valve, a conduit connected to the boiler drum and to a chamber ad'acent the diaphragm of said valve where y boiler pressure may be exerted upon .one side of the diaphragm, a conduit connected to the feed water line between the ump and said valve and leading to ump pressure may be substituted for the oiler pressure upon said diaphragm, means including a by-pass. valve to effect such substitutiom'excess pressure means adapted to act in the same direction with regard to said diaphragm, and means afiordingcommunication between the other side of said diaphragm and the feed water line between said valv'evand said regulatinnr device whereby the pumppressure plus the excess. pressure may act "against the boiler feed water pressure so that said valve maybe held o ifn when such substitution is i effected by the. y-pass valve.

4. In afeed water regulatlng systemffor a boiler pressure, the combination ofja diaphragm operated valve in the feed waterline, a fee water flow regulating device connected side of said diaphragm, means nacstablishing on the opposite side oi? said diaphragm fluid pressure equal to that between said valve and sald device, and a valve in said last named conduit lor cont-rolling the flow of fluid therethrough by means of which varying pressures in excess of boiler pressure may be established upon said diaphragm.

5. In a feed water regulating system, having a feed Water pump adapted to maintain feed water pressure in excess of boiler pressure, the combination of a diaphragm operated valve in the feed water line, a feed water flow regulating device connected in the feed water line between the boiler and said Valve, a conduit conncctedto the boiler drum and to a chamber adjacent the diaphragm of said valve whereby boiler pressure may be exerted upon one side of the diaphragm, a second conduit connected. to the feed water line between the pump and said valve and leading to said chamber whereby the pump pressure may be exerted upon said diaphragm, excess pressure means adapted to act upon and in the same direction with regard to said diaphragm, means connecting the opposite side of said diaphragm with the feed water line between said valve and said device, and means for controlling the flow of fluid through at least said last married conduit. v

6. In a boiler feed pipe, the combination of an orifice, afluid actuated valve disposed'adjacent thereto and responsive to changes in pressure drop through said orifice and urged toward closed position by the fluid pressure between said orifice. and said valve, excess pressure means associated with said valve, means for conducting actuating fluid to said valve from a point on the boiler sideofrsaid orifice, means for conducting actuating fluid to said valve from the feed water pipe ahead of said valve, and valve means associated with both said last named conducting means for controlling the flow of fluid therein.

7. The combination of a boiler,a feed water pipe, an orifice in said pipe, a feed water pump, a diaphragm actuated valve' positioned between the orifice and thepump, means for establishing fluid pressure on one side of said diaphragm equal to the pressure between said valve and said orifice. meanslor conducting fluid to the opposite side of said diaphragm from a point on the boiler side of said ori'fice,'means for conducting fluid to the same side of said diaphragm from a point between said valve and said pump, valve means associated with both said last named means for controlling the flow of fluid therethrough and varying the pressure exerted upon the diaphragm.

8. The combinatlon according-to claim 7 including adjustable excess pressure means supplementing the force controlled by said valve means. i,

9. The combination of a boiler, 'a feed water pipe, an orifice in said pipe, a feed atcr pump, a diaphragm actuated pressure controlling valve disposed between said pump and said orifice, means connecting one side of said diaphragm with the feed water line between said valve and said orifice, means connecting the opposite side of said diaphragm to the boiler side of said orifice,

means connecting the same side of said diaphragm with the feedline between the pump and said valve, and independently operable valve means associated with each of said last named means for controlling the flow of fluid therethrough and for varying the pressure exerted on said diaphragm. v

10. The combination of a boiler, a feed water pipe, an orifice in said pipe, a feed water pump, a diaphragm actuated valve in said pipe between said pump and said orifice, adjustable means tending to force said valve open, means for establishing fluid pressure equal to the pressure between said valve and said orifice on saiddiaphragm tending to close said valve, a conduit leading to the opposite side of said diaphragm for establishing boiler pressure thereon, a second conduit leading to the same side of said diaphragm for establishing pump pressure thereon, and independently operable valve means in each of saidconduits for increasing or decreasing theiopenings through which fluidv may flow in each of said conduits whereby the fluid pressure exerted tending to open the diaphragm actuated valve is a function of the relationbetween the open ings of said la'st named valve means.

'11. The combination of a boiler, a feed water pipe, an orifice in said pipe, a feed water pump, a pressure actuable valve in said pipe between said pump and said orifice having a part movable by and subjected to fluid pressures for varying the opening of said valve, means tending to force said valve open, means for establishing fluid pressure equal to the pressure between said valve and said orifice on said arttending to close said valve. fluidconductmg means leading to the opposite side of said part from a point on the boiler side of said orifice, a second fluid conducting means leading to the same side of said part from a point between said pump and said valve, and valve means in the latter of, said fluid conducting means for controlling tlie flow therethrough whereby fluid pressure tending to equal pump" pressure may be established on said part.

ieo

movement of-fiuid through both of sai 12. In combination, a boiler,a feed water pipe, a fluid pressure actuated valve disposed in said feed water pipe and having a part subjected to fluid pressures for moving bination of an orifice, a fluid pressure actu- I ated' valve disposed insaid feed water pipe in advance of said orifice and having a part subjected to fluid pressures for moving the valve, means for establishing the pressure existing at the outlet side of said valveon one side of said part, a conduit for conducting fluid betweenthe other side of said part and a point onthe boiler side of said orifice, a conduit for conducting fluid to the last named side of said part from a point on the inlet side of said valve, and means for controlling the movement of fluid through said last named conduit.

14. In combination, a boiler, a'feed water pipe, a fluid pressure actuated valve disposed in said feed water pipe and havinga part subjected to fluid pressures for moving the valve, means for establishin the pressure existing at the outlet side 0 said valve on one side of said part, a conduit for conducting fluid between the other side of said part and a point on 'the boiler side of said valve, a conduit for conductin fluid to' the last named side of said part rom apoint on the inlet side of said valve and means for controlling the movement of fluid through both of said conduits.

15. In a boiler feed water pipe, the combination of an orifice, a fluid pressure actuated valve disposed in said feed water plpe in advance of said orifice and having a part subjected to. fluid pressures for moving the valve, means for establishing the pressure existing at the outlet side of-saidvalve on one side of said part, a conduit for .conductmg fluid between the other side of said art and a point on the boiler side of said or' ce', a conduit for conducting fluid to the last named side of said part from a point on the inlet side of said valve and means for COIltlOllilg the 60117 duits.

16. In a boiler feed pipe, the combination of an orifice, a fluid actuated valve movable in response to changes in pressure drop acrow said orifice and urged toward closed position by the fluid pressure between said orifice and said valve, excess pressure means associated with said valve,- means for conducting actuatvalve tending to open'it, means for conducting actuating fluid to said valve from a point on the boiler side of said orifice, and means apart from said excess pressure means for positively forcing said valve to open position.

18. The combination of a boiler, a feed water pipe, an orifice in said pipe, a feed water pump, a pressure actuable valve in said pipe between said pump and said orifice having a part movable by and subjected to fluid pressures for varying the opening of said valves, means tending to force said valve open, means for establishing fluid pressure equal to the pressure between said valve and said orifice on said part tending to close said valve, fluid conducting means leading to the opposite side of said part from a point on the boiler side of said orifice, and means for exerting a force on the last named side of'said part to force and hold said valve in open position.

19. The combination ofa boiler, a feed i water pipe, an orifice in said pipe, a feed water pump, a pressure actuable valve in said pipe between said pump and said orifice having a part movable by and subjected to fluidpressures for varying the opening of said valve, means exerting a relatively constant force tending to open said valve, means for establishing fluid pressure e ual to the pressure between said valve an said orifice on saidpart' tending to close said valve, fluid conducting means leading to the opposite side of said part from a point on the boiler side of said orifice for establishing fluid pres- .sure on said part tending to open said valve,

and means for forcing and holding said valve in an" extreme position of its travel.

In testimony whereof, I hereunto afiix my signature. v

JOSEPH M. BARRETT.

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