US1020697A

US1020697A - Governing mechanism for mixed-pressure turbines.

Info

Publication number: US1020697A
Application number: US58690610A
Authority: US
Inventors: Oscar Junggren; Edgar D Dickinson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1910-10-13
Filing date: 1910-10-13
Publication date: 1912-03-19
Anticipated expiration: 1929-03-19

Description

.0. JUNGGREN & B. 1). DICKINSON. GOVERNING MEGHANISM FOR MIXED PRESSURE TURBINES.

APPLIOATION FILED 0011s, 1910. 1,02@,697. Patented Mar. 19, 1,912..

' a SHEETS-SHEET 1.

. Inventors. Oscar Junggr Witnesses; N EdgarDD'cKinson,

Theirb ttornes.

0. JUNGGREN & E. D.- DICKINSON. GOVERNING MECHANISM FOR MIXED PRESSURE TURBINES.

APPLICATION FILED 00T.13, 1910. gg gg y Patented Mar. 19,1912.

. 3 SHEEfi-SHEBT 2.

Fig. 7

L L L K L K l C L t. T Wutnesses: oscar lli giefi,

0. JUNGGREN & E. D. DICKINSON. GOVERNING MECHANISM FOR MIXED PRESSURE TURBINES.

APPLIOATION FILED 0GT.13, 1910.

Patented Mar. 19, 1912.

3 SHEETS-SHEET 3.

\nventors:

Oscar Junggren, Knson,

Lor ne hei iihlit'il l illfi tTATlEti Prtiitl li l i OSCAR JUNGGREN AND EDGAR D. DICKINSON, OI SCHENECTADY, NEW YORK, ASSIGN- GRS TO GENERAL ELECTRIC COMPANY. A CORPORATION OF NEW YORK.

, GOVERNING MECHANISM FOR MIXED-PRESSURE TURBINES.

i ,tiffithtiirt'. pe fi n of Letters Patent Patented Mar. 1%, Application filed October 13, 1910. Serial No. 586,906.

To (ZZZ whom it may concern: of current to the bus bars instead of robbing lie it known that. we, Osoan JUNooi-ucN them of current supplied by the other genand linen: l). Dickinson, citizens oi the erato'rs.

United States, residing at. Schenectady, The invention will be better understood county of Schenectady, State o'l New York, from the following detailed description, refon have invented certain new and useful lmerence being had to the accompanying drawprovements in Governing lvlechanisms for ings in which MiXed-lressure 'iurbines, of which the to]- Figure 1 is an end view of a mixed preslowing is a specification. sure turbine equipped with our improved This invention relates to systems of opregulating devices; Fig. 2 is a View of a porcrating a turbine with elastic fluid at ditt'ioniof the mechanism, taken at right angles lerent pressures and from different sources. to Fig. 1; Fig. 3 is a side elevation of the An ordinary instance of this kind of mixed pressure responsive device on a larger scale, pressure turbine, so called, is when the turand partly in section; Fig. 4 is a bottom Ito bine is driven normally by the exhaust steam plan view of the same; Fig. 5 is a view, -troin a reciprocating or other high pressure largely in section, of a modification; Fig. 6 engine, and is also arrangcd to be fed with shows a further modification, and Fig. 7 is steam at boiler pressure whenever there is a diagram of electrical circuits showing a failure of the low pressure supply, or in three polyph-ase generators connected in 550 case greater power is demanded from the parallel to a set of bus bars. turbine than it can produce with low pres- The turbine 1 receives low-pressure steam. sure steam. In such installations the regu through the conduit 2, which is controlled lating devices first open more and. more the by a valve operated by the rod 3. A speed low pressure valve or valves, and it the governor 4t driven by the turbine is connecessity arises the high pressure valve or nected with said rod by a customary form valves will then be opened. Under some of hydraulic motor 5, whose piston rod 6 conditions a speed-responsive device may rocks the cam shaft 7. Upon an increase of be used to control these two sets of valves, load, causing a slowing down of the turbine, opening them in succession as the speed of the motor causes the shaft 7 first to actuate the turbine drops oll either from a lessened the rod 3 to open the low-pressure valve, to supply of low pressure steam or i'roman inits fullest extent if necessary, and then to creasing load on the turbine. But when open the high pressure valves 8, one after the turbine is used to drive an alternating the other, to admitlive steam to the turbine current. generator coupled in parallel with from the main 9. Upon a decrease of load,

35 one or more similar generators driven by the reverse action takes place. Our im independent engines, it is desirable to supprovements have reference to certain addi plement the control of the speed governor tional mechanism whereby this operation by means responsive to the pressure of the of opening the valves will be ctlccted by a low pressure steam supply. The reason for lessening pressure of the low-pr assure steam,

this is thatgthe generators tend to keep in irrespective of the speed of the turbine, step, so thatthe one driven by the mixed whereby said turbine will be enabled to nessure turbine will not slow down on an carry its share of the load when driving an increase of load but will run as a synchros alternating current generator connected in nous motor, robbing current from the bus parallel With one or more similar generators 45 bars and driving the turbine wheels. There independently driven, as indicated in the is thus no oi iportunity for the speed goverdiagram, Fig. 7. To accomplish this, a nor to slow down, and without slowing down movable abutment, preterably a flexible it will not open the live steam valves. diaphragm 10, is arranged as one wall of a M Our invention provides improved means casing 11 which is connected by a. pipe 12 9 whereby the lessening of the pressure of the with the lmv-pressure steam conduit. This exhaust steam will at a. predetermined abutment is mechanically connected with point open the live steam valves, so that the stem .13 of the pilotvalve of the hydrauthe turbine will be enabled to carry its share lie motor.

m of the load; that is to say, its generator will In Figs. 1, 2, 3 and 4-, the edge of the continue to supply 1 s proportionate share diaphragm 1s clamped between a flange 14 on the casing 11 and a ring 15 secured clamping the edge of a central hole in the diaphragm through which the stem passes. A yoke21 on the ring 15 serves as a guide for the stem 17, whose lower end carries a block 22 provided with opposite lugs 23 engaging a lever 24. We prefer to construct this lever of two parallel bars, as shown, between which the block 22 has a sliding fit, so that its point of connection with said lever can be shifted 'by moving the casing 11. For this purpose We prefer to mount said casing on a bar 25 held in a frame 26. The casing has split lugs 27 receiving said bar and provided with screws 28 by which they can be tightened .upon said bar after the casing has been adjusted. The object of moving the casing and shifting the relative lengths of the arms of the lever 24 is to enable the apparatus to be adjusted to operate at different steam pressures in the low pressure conduit. This adjustment can be made for any given machine before the pipe 12 is connected, or the pipe may have a flexible coil 12 to permit of the movement of the casing 11. The lever 24 is fulcrumed at .2.) to the frame 26, and its free end is pivoted to a block 30 secured to the stem 13 of the pilot valve by means of a set screw 31. Upon a lowering of the pressure in the conduit 2 beyond a predetermined limit, the atmospheric pressure on the underside of the diaphragm lifts it, and with it the stem 13. The farther the block 22 is from the fulcrum 29 the higher will be the conduit pres- .sure at which the diaphragm will operate,

because the atmospheric pressure will operate at a greater leverage. /Vhen the pull ,of the vdiaphragm lifts the stem of the pilot valve, it also lifts the floating lever 32, pivoted at its middle to said stem and connected at one end to the piston rod 6, by the link 32 and the lever 32. The other end of the lever 32 is pivoted to the rod 33 which is attached to the lever 34 of the speed governor. Inasmuch as the piston rod 6 is held stationary by the liquid in the cylinder of the' motor 5, the rod 33 will be pushed up by the lifting of the diaphragm 10, thus compressing the spring 35 of the speed governor and forcibly changing the position of the weights 36. The upward movement of the pilot valve admits fluid pressure above the piston of the motor 5, so that the piston rod 6 will be drawn down and the first one or two high pressure valves 8 will be opened. The follow-up devices restore the pilot valve to its mid-position and the motor comes to rest in its new position.' If now the vacuum in the low-presure conduit increases, the diaphragm will be lifted again by the atmoswill close the high pressure valves in reverse order to that in which they were opened.

Fig. 5 shows a modification designed to prevent too delicate a response of the dia phragm, so that small fluctuations of low pressure steam will not aflect the valveoperating motor. The center of the diaphragm is perforated, and surrounding the perforation and on opposite sides of the diaphragm are two recessed plates 37 forming a chamber in which is received a head 38 on the upper end of the pilot valve stem 13. There is more or less play between said head and the top and bottom of said'chamber, so

that the diaphragm can move up and down within certain limits before it engages the head and actuates'the valve. hen it does so engage. the floating lever 32 can be 111- stantly lifted by reason of a slight lost mo tion inthe joint between said lever and the rod 33 of the speed governor; said lost'motion being provided for preferably by a slot 3.) in the rod 33 through which a pin 40 on the lever passes. The loss of motion is so small, however, that it does not seriously interfere with the control exercised by the speed governor. in order to provide for adjustn'lent to meet varying normal degrees through which'also can escape any steam leaking through the by-pass. A spring 44 acting upon the diaphragm and adjustable by means of a screw 45 affords a further means of regulating the action of the die-- phragm. I

In Fig. 6 the diaphragm is connected di. rectly to the lever 34 of the speed governor, instead of to the stem of the pilot ,valve. The operation, however, is the same as in the other form illustrated.

In accordance with the provisions of the patent statutes, we have described the principle of operation of our invention, together with the apparatus which we now consider to represent the best embodiment thereof; but we desire to have it understood that the Atmosapparatus shown is illustrative only and conduit, a high pressure supply conduit, and valves controlling the same, of a motor for actuating said valves, a pilot valve for the motor having a stem, a speed responsive device controlling said valve and motor, and means responsive to the pressure in the low pressure'conduit that engages said stem and controls said valve and motor independently of the speed responsive device under certain conditions.

2. The combination with a mixed pressure turbine having a low pressure supply conduit, a high pressure main, and valves controlling the same, of a motor for actuate ing said valves, a pilot valve admitting fluid pressure to said motor, a speed governor for operating said ilot valve, a ,diaphragm exposed on one slde to the low pressure steam and. on the other to the atmosphere, and operative connections between said diaphragm and said pilot valve.

3. The combination with a mixed pressure turbine having a low pressure supply conduit, a high pressure main, and valves controlling the same, of a motor-for actuatingsaid valves, a pilot valve admitting fluid pressure to said motor, a speed governor for operating said 'pilot valve, a diaphragm exposed on one side to the low pressure steam and on the other to the atmosphere, operative connections between said diaphragm and said pilot valve, and means for adjusting the-pull of said diaphragm.

4. The combination with a mixed pressure turbine. having a low pressure supply conduit, a high pressure main, and valves controlling the same, of a motor for actuating said valves, a pilot valve admitting fluid pressure to said motor, a speed governor for operating said pilot valve, a diaphragm eX- posed on one side to the low pressure steam and on the other to the atmosphere, a lever connected to said diaphragm and to said pilotvalve, and means for adjusting the point of-connection of said diaphragm with said lever. i

5. Thecombination with a mixed pres sure turbine having alow pressure supply conduit, a high pressure main, and valves controlling the same, of a'motor for actuatg said' valves, a pilot valve admitting uid pressure to said motor, a speed governor foroperating said pilot valve, a diaphragm exposed on one side to the low pressure steam and on the other to the atmosphere, a frame on which said diaphragm is adjustably mounted, a lever pivoted to said frame and to the stem of said pilot valve, and a stem attached to said diaphragm and provided with a block slidable along said lever.

In Witness whereof, we have hereunto set our hands this 12th day of October, 1910.

OSCAR JUNGGREN.

EDGAR D. DICKINSON. Witnesses:

BENJAMIN B. HULL, HELEN Onronn,