US1148425A - Valve for steam-engines. - Google Patents

Description

l. W. ADAMS & W. LEABH.

VALVE FOR STEAM ENGINES.

APPLICATION FILED Dec. 5. 1913.

Patented July 27', 1915.

4 SHEETS-SHEET I.

INVENITORSF lg, fim sflfms COLUMBIA PLANDGRAPII co., WASHINGTON. u, c.

J. W. ADAMS & W. LEACH.

VALVE FOR STEAM ENGINES.

APPLICATION FILED DEC. 5, 1913.

1,,425, Patented July 27, 1915.

4 SHEETS-SHEET 2- Fig.2

II e ll 0 III 1 c (j f2 8 WITNESSES- 2 INVENTORS.

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Km. 1 9 1 7H 2 y m J d w n m P APPLICATION FILED. DEC. 5, I913.

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- IN cTawze-s Z4 Z; Z66)" VENTORS' MdlrZG GaCZ/ away J. W. ADAMS & W. LEACH. VALVE FOR STEAM ENGINES.

APPLICATION FILED use. 5, 1913.

' LIQ Patented July 27, 1915.

4 SHEETS-SHEET 4- I A A igfl.

WITNESSES.

INVEN TORS. (7&71ze6w, (Wants JAMES WALTER ADAMS AND WALTER LEACI-I, OF BRADFORD, ENGLAND.

VALVE FOR STEAM-ENGINES.

To all whom it may concern:

Be 1t known that we, JAMES WVALTER Annie and VALTER LEACH, British subjects,

residing both at Bradford, county of York,

England, have invented certain new and useful Improvements in Valves for Steam-Engines, of which the following is a specification.

This invention relates to double beat or multiple beat valves for admitting steam to steam engines. Valves of this character constructed with the lower valve face of less area than the upper valve face so that the lower face of the valve may pass through the upper seat into its position on the lower seat have heretofore been coupled to a piston sliding in a cylinder, the piston having one surface subject to the pressure of the steam and the other surface subject either to full steam pressure or atmospheric pressure by means of an auxiliary valve co-axial with the piston and main valve.

The present invention consists essentially in the special construction and arrangement of parts for admitting steam to the cylinder of the auxiliary piston for balancing and operating the main valve and for providing a cushion of steam above the piston to prevent shock. I

The invention will be fully described with reference to the accompanying drawings forming part of the specification.

Figure 1. is a diagram showing the invention applied to an ordinary compound engine, the pipes c from the balancing cylinder of the high pressure valves being con nected to the intermediate steam pipe be tween the H. P. and L. P. cylinders. Fig. 2. is a diagram showing the invention ap plied to a uniflow engine for which it is especially suitable. Fig. 3. is a sectional elevation through the valve and valve chest showing the invention applied thereto. Fig. 4. is an enlarged detail section of balancing cylinder C and piston D. Fig. 5 is a sectional elevation through the valve and valve chest showing the balancing cylinder and piston with the piston valve for automatically opening and closing the main valve. Fig. 6 is an enlarged section of auxiliary piston valve F in same position as in Fig. 5 on line y. y. y. Fig. 8. Fig. 7. is a section showing the reverse position of the auxiliary piston valve F on line a a m. Fig. 8. Fig. 8. is an inverted plan.

The valve chest A of the engine with valve seats a a, a steam port A and the main Specification of Letters Patent. Patgnted July 2 7 1915 Application filed December 5, 1913.

Serial No. 804,903.

valve B are constructed in the ordinary way. On the valve chest A we mount a balancing cylinder C with a balancing piston D working therein and fitted on or connected to the spindle b of the main valve B. The piston D may be adjustable on the valve spindle and is secured thereto by locking nuts Z) or by cotters or other device, as in Fig. 5. The balancing cylinder C is placed preferably within and inelosed by the valve chest as shown butit may be exterior thereto if desired, and is fitted with inlet ports 0 through which high pressure steam from the valve chest A is admitted and also with exhaust ports 0 opening into an annular recess around the cylinder and connected by a pipe 0 to the lower limit of pressure such as the condenser or any part of the engine cylinder, intermediate pipe connecting the cyl nders or to the atmosphere, see Figs. 1 and 2. Instead of the inlet ports 0 merely opening into the valve chest they may by a suitable pipe be connected direct with the steam boiler or other steam supply.

The balancing piston D is fitted preferably with three packing rings 03 d and (Z to insulate the port and is formed with an annular groove (Z and ports (l which connect the top of the cylinder C with the inlet ports 0 and through them with the steam chest or other higher limit of pressure. The ports (Z may be of any suitable shape and preferably connect with the annular groove (6 cut around the piston.

In the arrangement as shown and described with reference to Figs. 3 and 4 the area of the balancing piston D is about equal to the excess in area of the valve seat a over the valve seat a by which the out of balance of the main valve is corrected. By making the area of the balancing piston D rather larger than the excess in area of the valve seat a over the valve seat a and alternately admitting steamat thehigh and low limits of pressure-above the balancing piston the main valve may be automatically opened and closed by the steam. I

Figs. 5 t0 8 refer to the arrangement in which the balancing piston D is made to open and close the main valve B, thus forming a steam operated valve gear. The balancing cylinder will now be called the Open ating cylinder. Referring to these figures in the cylinder C of the operatin piston D, ports 0 and 0 are provided'wfiich admit alternately the hi h and low limits of pressure to the top si e of the piston D, (it will be noted that the entry of port to the opoperating piston D. Above the balancing pistonD and fitted to. the main valve spin-' dle-b is a dash pot piston J provided with 1 tle nut j.

of the main Inallift.

piston rings j and j this works'in the dash potcylinder G. -The exhaust from beneath the dash pot piston is controlled by means ofa valve fitted at, M in the usualway. The piston J is screwed on to the valve spindle b and secured in position by the cas- Above the piston J and distantfrom'it equal to the ordinary maximum lift valve is a washer L fitted into a recess" in the dash pot cylinder G; acting on the top of this washer is a very strong spring H, which acts as a buffer spring and takes up any shock should the lift of the main valve for any reason exceed the nor- The. washer L also acts as a spring carrier for the small springs Z which are compressed between the top of the piston J and the washer L thus insuring a cushioned contact and absence of noise between these two parts. Resting on the dash pot piston J is a spring carrier is which supports the ordinary dash pot spring K, the latter closes the valve in the ordinary manner. r

p The balancing or operating cylinder C, piston D. and auxiliary valve F are all placed within and inclosed by the steam chest A for cleanliness and convenience.

' They may however be placed wholly outside the steam chest A at any convenient position, with the balancing or operating piston,

: upon,, or connected with the main valve spindle, and provided with an independent steam supply at the H. P. limit of pressure and connected to the exhaust or other L. P. limit of pressure.

As applied to an ordinary compound engine as in Fig. 1, the pipes 0 from the balancing cylinder C of the high pressure valves are carried to the intermediate steam pipe M connecting the high and low pressure cylinders. Thepipes from the balancingcylinder C of the low pressure valves are connected direct to the condenser. As applied to a uniflow engine as in Fig. 2., for which itis particularly applicable the pipeso from the top of the balancing cylinders are carried to the opposite sides of the main 'enginepiston by which the steam released from the balancing cylinders is entrapped between the main piston and the B the balancing its bottom position when the lower limit of square inches and is also acting upward on an area equal to the inside of the bottom valve seat say N square inches. This makes the valve out of balance in a downward direction equal to P lbs. absolute (MN) sq. in. and the area of the balancing piston must be so proportioned that (P])) Z: P (MN) if p be the lower limit of pressure, and Z the area of the balancing piston.

In the above cases the main valve B will be exactly in balance when shut. If it is desired to have the main valve B out of balance in a downward direction when shut this may be regulated to any desired degree by reducing the area of the balancing piston D. If it is desired to place the main valve- B out of balance in an upward direction when shut, this may be regulated to any desired degree by increasing the area of the balancing piston D.

Working description of F 2'9. 3.VVhen the main valve B is closed on its seat, the balancing piston D in its lowest position and the space between the top of the piston and cylinder in direct communication with the lower limit of pressure the main valve B is out of balance in a downward direction while the balancing piston C is equally out of balance in an upward direction. This places the whole system in balance. The gear for opening the valves (which may be any ordinary gear) now comes into operation and lifts the main valve B from its seat a a at the same time the balancing piston D moves upward in the balancing cylinder C and in this upward movement the top packing ring shuts off the connection 0 and c to the lower limit of pressure while the middle packing ring opens up the ports 0 admitting the higher limit of pressure through the ports (2* to the space above the balancing piston. We have now the same pressure acting upward and downward on both the main valve and the balancing piston therefore the whole sytem is in balance again and ready for the operating gear to close the valve. On closing the main valve piston D is again moved to pressure is gradually opened to the balancing cylinder and the connection to the higher limit of pressure shut off thus again putting the valve in equilibrium ready for the cycle of operations to be repeated.

W orkz'ng description of F 7198. 5 to 8.The

main valve B is shown in its closed position. The auxiliary valve F has just been moved to its lowest position (by means of the operating gear which in the drawing is shown as a cam gear but may be replaced by eccentric, trip, or any other gear deriving its motion from the crank shaft of the engine) thereby opening up the top of the balancing cylinder through ports 0, 7, e and e (see Fig. 6) to the L. P. limit and closing off the ports 0 and f (Fig. 5) to the H. P. limit. The pressure in the steam chest A now acts upon the underside of the operating piston D (which has an area in excess of the out of balance area of the main valve) and raises it against the. resistance of the L. P. limit above the piston D causing the main valve B to open. The main valve will remain open until the auxiliary valve F is moved to its top position, (Fig. 7) thereby cutting off or closinglthe ports 0 f 6 and 6 (Figs. 5 and 6) to t e L. P. limit and opening up ports f and c (Fig. 7 to the H. P. limit from the steam chest. This places the balancing piston D in equilibrium and the spring II closes the main valve 13. The valve B now remains out of balance in a downward direction (thus insuring steam tightness throughout the whole expansion stroke and the greater part of the return stroke) until the point of opening when the auxiliary valve F is again moved to its lowest position and the cycle of operations is repeated. As soon as the main valve leaves its seat it is placed in equilibrium, therefore the upward pressure on the piston D will cause the valve, piston and spindle to travel upward with a rapidly increasing velocity and momentum. This is resisted and overcome by the compression of the L. P. limit of pressure inclosed in the space between the top of the balancing piston and the cylinder after the piston ring d has shut off the port 0 to the L. P. limit (this is done immediately the piston moves up.) The pressure of steam left above the balancing piston and the amount of cushioning can be regulated to any desired amount, by means of a valve controlling the port 6. In case the compression is not sufficient to bring the valve and spindle to rest, the dash pot piston J comes into contact with the large buffer spring H, which thus acts as a safety device to prevent the piston D coming in contact with the top of the cylinder C.

The whole of the operating gear can be made exceedingly light on account of the fact that the auxiliary valve is balanced and the force exerted by the cam N on the roller 11. is simply that required to overcome the friction of the auxiliary valve F.

IVhat we claim as our invention and de sire to protect by Letters Patent is:-

1. In a double beat or multiple beat drop valve, the combination of a cylinder, and a piston connected to the valve and working in said cylinder, the cylinder having a port for admitting the high and low limits of pressure thereto above the piston, the piston operating to close said port and cut off the low pressure steam before completing its stroke, leaving a cushion of steam at the top of the piston.

2. In a steam engine, the combination with a valve, of a cylinder, :1. dashpot piston connected to the stem of said valve and operating in said cylinder, a spring acting on the dash-pot piston, and a cushioning spring normally inactive but operative to yieldingly resist over-motion in the opening of the valve.

In a double beat or multiple beat drop valve the combination with the valve, the valve chamber and the valve seat, of a balancing or operating cylinder provided with steam ports, a balancing or operating piston therein connected with the valve, and an auxiliary valve and Valve chamber to control the admission of steam of high or low pressure to the balancing or operating cylinder.

4. In a double beat or multiple beat drop valve the combination with the valve, the valve chamber and the valve seat of a balancing or operating cylinder provided with steam ports a balancing or operating piston therein, connected with the valve, and an auxiliary valve and valve chamber to control the admission of steam of high or low pressure to the balancing or operating cylinder, and means for operating the auxiliary valve.

5. In a double beat or multiple beat drop valve the combination with the valve, the

valve chamber and the valve seat of a balancing or operating cylinder provided with steam ports a balancing or operating piston therein connected with the valve, an auxiliary valve or valve chamber to control the admission of steam to the balancing or operating cylinder and a dash pot piston and buffer spring to prevent the balancing pist'on coming in contact with the top of its cylinder.

In testimony whereof we have hereunto set our hands in presence of two subscribing witnesses.

JAMES WALTER ADAMS. IVALTEB LEAUI'I.

Witnesses:

HARRY L. KrrsoN, ROBERT TARR.

Gopies of this patent may be obtained for five cents each, by addressing the Gommissioner of Patents Washington, D. G4

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