US2436815A - Pressure operated valve - Google Patents

Description

March 2, 1948.

yw. o. LUM

PRESSURE OPERATED vVALVE:

File@ March 15, 1944 f /R Inventor:

- Wa'LIcJer` O. Lum,

b5 JV w/w His Atborhqg.

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PRESSURE mm VALVE Walter 0. Lum, Schenectady, N. Y., assigner to General Electrl Nh York eCemrlnzaeorrmtienor Application March 15. 1944, Serial No. 523,5

4 Claims. (Cl- 137-153) Forcertainapplicationaitisrequiredthata numberoffuelnozzles. eachsupplyingfueltoa separate combustion chamber, kbe connected in parallel to a common fuel header and that during the operation equal amounts of fuel over a widerangeofoperationfromnoloadtofull load be supplied from the header to each fuel nozzle. It is further required that upon changes Y in load. the fuel supply to all the fuel nozzles be varied evenly. promptly and simultaneously. Buch an application is met with. for example, in the case of gas turbine power plants wherein a number of relatively small combustion chambers (for example as many as 12 or more) arranged in a circle supply gas to a turbine wheel, each combustion chamber supplying gas to a small arc of the wheel. In such an application, it is lm portant that the wheel be equally loaded throughout its circumference which means that each combustion chamber at all loads must supply equal temperatures of gas to the nozzles of the turbine. It is also n that fluid fuel be metered very accurately to the combustors over an extremely wide range of flow rates. v

The object of my invention is to provide an improved fuel distributing system and an improved fuel nozzle for use therein for meeting the foregoing requirements, and for a consideration of what I believe to be novel and my invention, attention is directed to the following specification and to the claims appended thereto.

In the drawing. Fig. 1 is a diagrammatic view of a system embodying my invention, and Fig. 2 is a longitudinal sectional view through one of my improved fuel nozzles.

Referring to the drawing, I indicates a fuel tank connected by a pipe line 2 to the inlet of a suitable fuel pump I which has its discharge side 4 connected to a fuel header I. In the case of an installation wherein a number of combustion chambers are arranged in a circle, header I may be in the form of an annular pipe to which the fuel nozzles of the several combustion chambers are connected. In the present instance, by way of example, I have shown three fuel nozzles 2 pipe line I by a by-pass pipe II in which is located a suitable hand control valve II. When hand control valve II is open. fuel discharged from pump 4 can ivy-pass through pipe I0. s, and2backtopumplandthesupp1ytankl so that when valve II is open. no fuel oil is supplied to header I. As valve II is closed. fuel oil will be supplied to header I, its pressure being gradually increased as the valve moves toward closed position. Thus, valve II forms a control valve for resulating the amount of fuel supplied to header I and the pressure in the header.

Each fuel nozzle I may supply fuel to a separate combustion chamber. The fuel nomle may be of a type in which-fuel is atomized to the combustion chamber by pressure alone or it may be of a type in which it is atomized by means I connected to header I in parallel, this being intended to represent any suitable number of fuel nozzles connected to a header of any suitable type. The branch pipes connecting header I to of air. In the present instance, the latter arrangement has been illustrated, I2 indicating a pipe line leading from a suitable source of air pressure. Referring to Fig. 3, II indicates a cylinder in which is mounted one end of an elongated hollow piston II. In the h ead of cylinder I5 is a discharge opening I'I with which a pipe 8 connects. In the discharge opening is a plug I8 having a central opening II for ilow of fuel oil to opening I'I. Plug II is provided with a threaded stem 2I on which is a nut 2| with which engages one end of a spring 22. The other end of spring 22 is located inside piston II and engages head 23 of the piston. Plug II is provided with a suitably shaped socket in its left hand end to receive a tool for turning the plug. By turning plug II, nut 2| may be moved longitudinally of cylinder II to adjust the compression of spring 22, the nut being held from turning by reason of its engagement with the end of the spring. The right hand end of cylinder II (Fig. 2) is counterbored to provide a fuel oil supply chamber 24 with which a fuel oil supply pipe I connects. In fuel oil supply chamber 24 is a suitable filter screen 25 carried on a metal framework 2I. From the above described arrangement, it will be seen that the right hand face of the head 23 of piston II is subjected to the pressure of the fuel oil supplied through pipe 1. In the wall or sleeve portion of the hollow piston I6, just in advance of the shoulder formed in cylinder I I by the counter-bored end, is an opening 21 which connects fuel oil chamber 24 with the interior of cylinder I5 and hence with discharge pipe I. Connected to the right hand open end of cylinder I5 by means of a suitable coupling III is a cylinder II, the end I2 of which is provided with eled edge at the right hand open end of cylinder I5 to make a tight flt with cylinder 3l and seal against the open end of cylinder i5. This sealing arrangement is more fully described in my copending application, Serial Number 526,583, filed March 15, 1944. The outer surface of post 36 in connection with cylinder 3i forms an air chamber 38 with which connects'the air pipe line I2. Inside post 36 is a spool 33 having a discharge opening surrounded by a valve seat with which engages the pointed end of a fuel oil metering pin 40, such pointed end forming a valve head 403. Metering pin 43 projects out through a iluid control opening in bushing 4I threaded into(y the end of post 33 and is provided with a y head 42 by which it is suitably attached to the 1 right hand end of piston I6. In metering pin 40 is a longitudinally extending metering groove 43 which increases gradually in size from the left hand end of the metering pin toward the right hand end. Between spool 33 and atomizing head 32 there is a fuel oil chamber 44 which is connected by passages 45 to air flow passages which connect air chamber 38 with the swirl chamber 35. These air passages each comprise an axially extending portion 43 formed in the peripheral portion of the swirl head and a tangentially extending portion 41, the fuel passages 45 communicating with the tangentially extending portions 41. With this arrangement, the fuel and air enter the swirl chamber tangentially, thus setting up a swirling movement of the air and fuel in the chamber to provide a thorough mixture before the fuel and air are atomized through the opening 33 to the combustion chamber. At 43 is a suitable coupling means by which the fuel nozzle may be fastened in the wall of a combustion chamber.

The operation is as follows:

Assume that fuel oil pump 3 is operating and that valve Il is open. Under these conditions, the oil discharged from pump 3 will flow through by-pass I0 back to pump intake line 2, nov oil pressure being built up in header 5. The pointed heads 40a of metering pins 40 in each of the fuel nozzles will be against its seat, closing the discharge opening in spool 33. Now, as valve Il is moved toward closed position, oil will be directed to header 5 and will be supplied from header 5 to each of the fuel nozzles through pipes 1. The fuel oil entering a nozzle through pipe 1 builds up a pressure in fuel oil chamber 24 which pressure acts on cylinder head 23 in a direction tending to move it toward the left to move the head of the metering pin away from its valve seat. At the same time oil ows through by-pass opening 21 in the wall of cylinder i3 to the return pipe 3. As valve Il is moved further toward closed position, a pressure will be built up in the fuel oil chamber 24 suillcient to move piston I6 against the action of spring 22; and, after a predetermined short movement, by-pass opening 21 is covered by the cylinder wall. When this happens, the pressure is built up more quickly in oil chamber 24 since a part of the oil can no longer escape through by-pass opening 21. As a result, the metering pin 40 is moved quickly to a definite metering position to admit fuel to fuel chamber 44, from whence it is discharged through openings 45 in the'atomizing head to swirl chamber 35. Inthe swirl chamber 35 the fuel is mixed with air under pressure conducted thereto from the air chamber 33 through the passages 45, 41. The mixture finally is discharged through the spray opening 33 into a combustion chamber or other consumer. The metering pins of all the fuel nozzles will be moved by the same amount which means that each will be feeding an equal amount of fuel to its combustion chamber. Now, as the pressure is increased and decreased by moving valve Il toward closed and open positions, the pressure in header 5 is varied and the amount of fuel supplied by each fuel nozzle to its combustion chamber varied. The fuel flow in each nozzle is controlled by the axially extending metering groove 43, cooperating with tre fluid control opening in bushing 4|, and' by the pressure of the fuel oil. Because of the comparatively long travel of metering pin 40, accurate metering of fuel over a wide range of flow rates is possible by careful design of the contour of slot 43.

There is a substantial drop in oil pressure in the fuel oil as it flows past the metering pin and through spool 33 to fuel oil chamber 44.` As a result, the difference in head due to the fuel nozzles being connected into header 5 at different points has a negligible effect on the distribution of the oil to the respective fuel nozzles. It will be understood that initially the springs 22 of the several fuel nozzles are adjusted relative to each other so that all the fuel nozzles operate in a like manner.

When valve Il is opened to shunt the flow of fuel oil from header 5, as soon as the by-pass opening 21 reaches a point where it communicates with fuel oil supply chamber 24, the oil pressure in the supply chamber is quickly released through opening 21, thus permitting the metering pin to move quickly to its final closed position. Due to this arrangement, the fuel nozzles, when being put out of operation, will all be quickly and simultaneously moved to their closed positions thus insuring positive shut-off of fuel oil to all the combustion chambers. This is one important feature of my invention since it does away with the possibility of fuel oil being supplied to certain of the fuel nozzles while others are entirely closed.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a variable pressure wide-range fluid metering device, the combination of a casing having walls forming a bore including an inlet chamber and a fluid control opening and a discharge opening in series ilow relation, an axially slidable metering pin disposed in the bore and adapted to project at least partially into and cooperate with the discharge opening, said metering pin having a rst portion cooperating with the dis-v charge opening to form a positive shut-ofi valve and a second axially spaced portion shaped to define with the fluid control opening a variable area metering orifice in series flow relation with the shut-off valve, means responsive to pressure in the inlet chamber for positioning the metering Din to consecutively open the shut-off valve and then vary the size of the metering orifice as a predetermined function of increasing inlet chamber pressure, said pressure responsive means including a piston connected to the metering pin and slidably disposed in said bore with an outer end surface subjected to fluid inlet pressure tending to move the piston toward metering position,

of positions adjacent the valve-closed position,

whereby the piston is caused to move quickly between the valve-closed position and the minimum flow metering position.

2. In a variable pressurey Wide-range fluid metering device, the combination of a casing having walls forming a bore including an inlet cham- Iber and a fluid control opening and a discharge opening in series flow relation, an axially sutiable metering pin disposed in the bore and adapted to project at least partially into and cooperate with the discharge opening, said metering pin having a first portion cooperating with the discharge opening tio form a positive shut-off valve and a second axially spaced portion shaped to define with the fluid control opening a variable area metering orifice in series ow relation with the shut-E valve, means responsive to pressure in the inlet chamber for positioning the metering pin to consecutively open the shut-off valve and then vary the size of the metering orifice as a predetermined function of increasing inlet chamber pressure, said pressure responsive means including a piston connected to the metering pin and slidably disposed in said bore with an outer end surface subjected to uid inlet pressure tending to move the piston toward metering position, means biasing the piston to valve-closing position, means for adjusting said biasing means, the shape of said second portion of the metering pin being so related to the fluid control opening that a metering orifice is formed only during the occurrence of a pressure in the inlet chamber above a preselected minimum value, said piston having a restricted port arranged to communicate uid from the inlet chamber to the opposite side of the piston only when the piston is within a llimited range of positions adjacent the closedvalve position, whereby the piston is caused to move quickly between the valve-closed position and the minimum flow metering position.

3. In a variable pressure wide-range fluid metering device, the combination of a casing forming an inlet chamber and a fluid control opening and a discharge opening in series flow relation, an axially movable fluid metering pin disposed in the casing and havingan end portion adapted to cooperate with the discharge opening to form a positive shut-oil.' valve and an intermediate portion shaped to define with the fluid control opening a metering orifice of a size variable as a preselected function oi the axial position of the pin, a cylinder formed in the casing and communicating with the inlet chamber, a piston slidably disposed in the cylinder with an outer end surface subjected to fluid inlet pressure and connected to the metering pin, means in the casing biasing the piston to a position wherein the metering pin cooperates with the discharge opening to positively stop the flow of iluid, and a restricted passage arranged to by'- pass fluid from the inlet chamber to the opposite j and arranged to be closed by initial movement of the piston when nuid pressure in the inlet cham. ber rises to a preselected value whereby the piston is caused to move quickly to a fluid-metering position.

' 4. In a variable wide-range fluid metering device, the combination of a casing having a longitudinal bore with a iluid discharge port adjacent each'end thereof, a hollow piston member slidably disposed in a portion of said bore and having an open end communicating with one of said discharge ports, walls dening iiuid inlet passages arranged to communicate fluid inlet pressure to the outer end surfaces of the piston remote from said open end, said bore having a second portion forming rst and second axially spaced openings, the first being a fluid control opening arranged to communicate with said inlet passages and the second being a discharge opening arranged in series flow relation between the first opening and the other of said fluid discharge ports, metering pin means projecting through said first opening and connected to the piston to be positioned thereby, said pin having a first portion shaped to cooperate with the first uid control opening to deilne a variable orice of an area which varies in a preselected manner as a function of metering pin position, the pin also having an axially spaced end portion constructed and arranged to cooperate with the second opening to form a positive shut-oi! valve, and means.

associated with the piston for biasing the metering pin to valve-closing position, said piston having a side wall portion dening a restricted bypass port communicating between the inlet passages and the interior of the piston, the location of the by-pass port being so related to the conguration of the metering pin that initial movement lof the piston first opens the shut-olf valve and then covers the by-pass, whereby the presysure differential across the piston is increased to quickly move the pin to a fluid metering position.

WALTER O. LUM.

REFERENCES CITED The following references are of record in the flleof this patent:

UNITED STATES PATENTS Number Name Date 2,290,350 Olches July 2&1, 1942 2,334,679 Mason et al. Nov. 16, 1943 1,644,372 Gray Oct. 4, 1927 2,301,496 Aldrich Nov. 10, 1942 2,164,411 Kennedy July 4, 1939 2,071,143 Scott Feb. 16, 1937 1,824,952 Graham et al Sept. 29, 1931 2,345,402 Lubbock et al Mar. 28, 1944 2,349,221 Gorrie May 16, 1944 2,199,454 Andler et a1. May 7, 1940 2,145,429 Nelson Jan. 31, 1939 2,024,270 Binnall Dec. 17, 1935 2,178,223 Czamecki Oct. 31, 1939 1,661,450 Van Sant Mar. 6, 1928 2,310,504 Aubert Feb. 9, 1943 1,985,279 Buller Dec. 25, 1934 1,995,480 Murphy Mar. 26, 1935 2,070,411 Powers Feb. 9, 1937 2,100,997 Russel Nov. 30, 1937 1.862.910 Schutz June 14, 1932 2,316,881 Morse et al. Apr. 20, 1943 1.844.164 Jewett Feb. 9, 1932 1,876,980 Lentell, Jr. Sept. 13, 1932 868,757 Bennett Oct. 22, 1907 1,720,389

sinks July s, 1929

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