US816348A - Cylinder-compression-relief valve. - Google Patents

Description

QNO. 816,348.

PATENTED MAR. 27, 1906.

J. W. MILLER. CYLINDER COMPRESSION RELIEF VALVE.

l APPLICATION FILED JUNE 14, 1905.

3 SHEETS-SHEET Z.

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No. 816,348. I PATENTED MAR. 27, 1906.

' J. W. MILLER.

CYLINDER COMPRBSSION RELIEP'VALVB. APPLICATION FILED JUNE 14, 1905.

l3 SHEETS-SHEET 3.

70 LEHIIM gh f `. JOHN W. MILLER, OF CHICAGO; ILLINOIS.

`GJYl..l'NDEI-CONIPFESSlON-RELIEF VALVE.l

Speccation of Letters Patent.

. Patented March 27,1906.

Application iled June 14, 1905. Serial No. 265,221.

To Lugvi/1,0m it may concern.- y

' Be it known that I, JOHNl W. MILLER, a citizen of the United States, residing at Chicago, in the county of Cook vand State of Illinois, have invented a certain new and useful Y Improvement in Cylinder-Compression-Relief Valves, of which the following is a specification.

My inventionrelatesto steam-engines, and particularly to means for relieving the compression in a steam-engine'cylinder at the end of the stroke of the piston. y

The object of my invention is to provide mechanism by means of which the compres.-

sion or back pressure which occurs in any steam-engine cylinder after the exhaust-port 4is closed `and before the pistonv reaches the end of its stroke may be automatically relievedthereby doing away with the danger of the cylinder-head blowingout or other parts of the mechanism being broken, as freuently occurs. The occasion for the use of yt e invention arises principally when the fsteam is cut off in the cylinder before the piston reaches the end of its stroke and is used expansively in the cylinder from that ipoint to some otherlpredetermined point in the cylinder.

My invention, broadly stated, consists in the use of a compression-relief valve normally held closed by the pressure of live steam which is adapted when the live-steam pressure is removed to be opened by the compression-pressure in the cylinder and allow that compression-pressure to escape, l'thereby relieving the cylinder from all strain due to` su ch back pressure or compression.

My invention further consists in the details of the valve itself and in other features, which will be hereinafter .more fully described and claimed as the specification proceeds.

The valve-of my invention may be applied to any form of engine-cylinder and steamvalve mechanism by making connections at the proper places, as will readily appear to any one familiar with the different types of such engines, and I have in the drawings shown the device applied to a simple slide- Valve'engine for the purpose of illustrating the connection of my relief-valve to one form vof engine; but Ido not thereby intend to limit myself to the application of the device to this or any particular form of engine construction except as the same may be specifically limited in the claims.

As is well understood in the engine art,

-which it may occur.

i there are two ways in which steam may be used in a. cylinder-first, full-stroke direct pressure, and, second, the expansion method. In the first live steam is admitted to one end of the cylinder throughout the entire length of the stroke of the piston, the exhaustort at the o posite end being wide open. T ere is therefbre no compression or back pressure in the cylinder to resist the forward pressure' of the steam, and consequently no back pressure or compression occurs', and my device is of no use here. In the second method steamis admitted to the cylinder while the piston is moved a vcertain distance and is then cut off, the steam within the cylinder being allowed to expand to drive the piston farther along the cylinder, Athe exhaust-valve at the opposite end being open. If an engine-valve is used which will allow the steam to thus exand to the end of the cylinder before theexaust-valve at the opposite end is closed could be practically designed, there would be no compression or back pressure and no cause for my device; but when in practice steam expansion is sought beyond la certain oint in the cylinder (obtained by-addin insi e lap inv a plain slide-valve en ine) the ex aust-port in the end of the cylin er to which the piston is moving is necessarily closed, with the result that steam, air, or gas remaining in that end of the cylinder is compressed, thereby creat-l ing compression or back pressure in that end of the cylinder, which negatives the effective force of the expanding steam and at the same time is apt to blow out the cylinder-head or otherwise injure the engine. -My device is designed to do away with this back pressure or compression in any and all forms of engine in For the purpose of illustration merely I have shown it applied to a plain slide-valve engine having inside lap.

With the understandin@ above noted, Figure 1 is a central sectiona detail view oi the engine-cylinder having the valves of my invention applied thereto, the slide-valve being in a position where steam is just being admitted to the left-hand e'nd of the cylinder. Fig. 2 is a central'seetionaldetail view of the relief-valve of my invention, taken on line 2 of Fig. l. Figs 8 and 4 correspond with Fig. l, except that in Fig. 3 the valve and piston are shown at cut-oil position and in Fig. 4 they are shown in the position where the exhaustport is closed and compression begins at the right-hand end of the cylinder.

Again referring to the drawings, the nu.-

. ting steam within it in the space 21.

meral 11 indicates the cylinder, closed by heads 12 and 13. In the cylinder is a piston 14 on a piston-rod 15, adapted to slide back and forth through a stuiiing-box 16 in the' cylinder-head 13. This piston-rod is con.- nected beyond the figure to the cross-head, which is in turn connected to the drivewheels of a locomotive or the ily-wheel of a stationary engine. Above the cylinder is the steam-chest 20, having means for admit- At each end of the cylinder is the usual port or passage- ways 22 and 23, entering the steamohest 20 at points 24 and 25near the middle, as shown. Between these ends or ports 24 and 25 there is cut in the top of the cylinder an exhaust passage or port 27, as shown.

lidably mounted within'the steam-space 21` and adapted toslide backward and forward on the surface or seat 30 on the top of the cylinder and also adapted to slide upon the surface 31 upon the under side of the steam- .chest 2O is a slide-valve 33, mounted upon a valve-rod 34, passing through the stuffingboxes 35 in the end of the steam-chest. f This valve has in its under side an opening of suoli a length that in one position it affords an opening between the steam-passage 24 and the exhaust-port 27, the solid parts or valve-faces 42 and 43 of the valve closing the opposite steam-passage 22 vor'23 from the one which is opened. As is well known in this form of valve, the inside lap of the valve is produced by adding to the inside edges of the solid parts or faces 42 and 43, or, in other words, making the distance 40 betweenthem less than the distance between the two inside edges of the steam-ports. Assuming now that this engine is used without my device, steam is first admitted through chest 21 and passage 22 to the space 45, Fig. 1. The direct pressure of the steam moves the piston to the position of Fig. 3, space 45a being full of live steam. In this position the slide-valve `33 closes port 22, and the steam in 45a is cut off" and ready to expand to volume 45h. When the piston reaches' this position, the face 43 of valve 33 closes port 23, thereby confining air, gas, or steam in 'the space 46h, with the resultthat harmful back pressure or compression, as heretofore described, is produced in space 46h and continues until the pis-ton reaches the right-hand end of the cylinder. When the piston goes back to starting position, compression is produced in space 45:L in the same way` As heretofore described, the object of my invention is to provide a. valve to relieve this compression. In order to do this, I provide two valves such as are illustrated in Fig. 2 and connect them to the cylinder in the manner shown in Fig. 1. The valve consists in a shell or casing .60, having at its bottom a pipe 61, connected to the end of the steam-cylinder. The upper end of this pipe terminates in horizontal valve-seat 62 within the casing.

-At right anglesto this valve-seat 62 is another pipe 64, conneoting with an annular space 65 within the valve and open except, as hereinafter described, to the pipe 61, which is one exhaust-pipe from the cylinder. Vertically slidably mounted inside the casing 60 is a differential valve 66, having two'pistons 67 and 68, the lower piston 67 being smaller than the upper and adapted to slide up and down inthe bearings 69, making a tight joint therewith by means of the packing-rings 70.- This valve is adapted to rest at 71 on the valve-seat 62, thereby, as shown, closing the communication between the pipes 61 and 64. The upper piston 68 isadapted to slide up and down in the portion 75 of the casing and is packed in contact therewith by the packing-rings 76. Entering the side of the casing 60 above the piston 62 is a pipe 78, normally connected to lthe steam-chest of the engine, as shown in Fig. 1, so that steam may be admitted into the space between the top of the piston`62 and the cap 81, screwthreaded at 82 into the top of the casing 60. This cap may be constructed to be bolted on, if desired. In the cap 81, screw-threaded at 84, is a rod 85, adapted to be held in position by a check-nut 86. On the lower end of this rod'85 is a head 88, adapted to bear against a projecting lug 89 on the top of the piston 68 of the valve 66.v By adjusting this head 88 up'or down by means of the rod and check-nut 86 I can vary the distance which the piston 66 can move up and down from the valve-seat 62. This adjustment, however, should always be such that the space 80 above the valve 66 always exists-in other words, so that the top of the piston 68 cannot come in contact with the bottom of the cap 81.

From an inspection of Fig. 2 it will be seen that if steam is allowed to pass through the pipe 78 into the space 8() it will hohl the valve 66 down upon the valve-seat 62 against an equal pressure per square inch of steam in the pipe 61, bearing against the under side of the piston 69, but thatif the steam-pressure in the space 80is reduced or removed, the pressure in t ie pipe 61 remaining the same, it will raise the valve 66 a distance equal to the distance between the parts 88 and 89, heretofore described, and allow the steam, air, or gas in the pipe 61 to pass between the valve-seat 62 and the lower end 71 of the piston 67 through the passage-way 64 out into the air. practical operation I connect the device tov the cylinder as shown and so arrange the top plates and 101 of the. valve 33 that steam is admitted in the position of Fig. 1 to the pipe 73 just an instant before it is admitted through the passage-wa)Y 22 to the sparc 45 in the cylinder, from which it follows that during the time the live steam is in spaces 45 and 45a the valve 66 is held down against the .valve-seat 62 and none of the live steam can escape through the pipe 61 4over the valveseat 62 and out of the pipe 64. While these y Way'lOO still remains open, so the left-hand in the cylinder is valve 66 still is held closed until the pressure considerably reduced. When now the piston has moved to the posi- 'tion ofiFig. 4 and compression begins, as

heretofore described, in the space 46", the compression air or gas in that space immediately raises the valve 66 in the right-hand compression-valve of Fig. 1 and allows that air or'gas to escape i the exhaust-pipe 27 and thereby absolutely lower' end 120 of the valve-stem 121. 'this case the water drains down into the relieve they cylinder from the compression. When the piston reaches the extreme righthand end of the cylinder, all of the parts are in the reversed position from that shown in Fig. 1 and-steam is admitted to the to of the right-hand relief-valve, while the lefthand one has its steam-pipe 78 open to the exhaust, the same as the right one has in Fig. 1, and the operation is repeated as the piston moves back to its original position, the lefthand relief-valve allowing 'the compression which then occurs in the space 45*1 to escape into the ipe 27 through the left-hand pipe130.

In. or er to provide that no watershall collect lineither relief-valve, I provide two systems of drainage, one consisting of a ballvalve 110, lying in a recess 111 and adapted to allow the passage 112 to remain open when there is no steam-pressure in the space and to close 'that passage-Way 112 when steam passes from the passage or space 80 through the pipe 113 against' the ball 110. I also provide a piston valve 116, having serrated ledges 117, through which Water may pass from theispace 8() when the valve is lifted off from its seat 118 by the action of steam or gas from the pipe 61 bearing against tlIie n space 122 surrounding thecvalve 66 and passes out `through the openings 123. As the top of .this valve'117 is larger than the area of the bottom 120 exposed to the pressure in the pipe 161, this'valve is always closed in exactly the same way that the main valve 66 is closed when live steam is in space 80, as heretofore described.

By the use of my valves it is possible to increase both the' inside and outside lap of the main valve, and thereby greatly increase the expansion range of the engine.

s heretofore stated, I do not wish to be' limited to the application of my valve to any via the space 105 and ports 106, to-

through the pipe 13() intoy articular form of engine, nor do I intend to limit myself to exact forms of valve shown and described, For convenience the invention has been described throughout the speci- {ication as one relating .to a steam-engine; but manifestly air orfsome other gas may be used in lace of steam without departing from my invention..

By defining the sup lemental relief-valve asconnected to the cyllnder or to one end of the .cylinder I do not mean that it shall be connected directly to the cylinder in the manner shown.'v It may be connected as a branch of any pipe or passage leading from the cylinder-as, for instance, the passage 22 or 23.

Having thusdescribed my invention, what -I claim as new, ters Patent, is-

and desire to secure by Let- 1. In combination with an en cylinder, a iston and piston-ro inthe cylinder, and va ve mechanism to control the admission and thecylinder; a su ine having a plemental valve connected to the cylinder a apted when opened to allow the gas within the cylinder to exhaust, adapted to be o ened by pressure of gas in the cylinder, an mechanism connecting said su plemental valve with the main-valve meclianism adapted to hold the supplemental valve closed during the -portion of t e enginestroke that steam is working in the cylinder and to release the supplemental valve during the remainder of the stroke of the engine.

2. In combination with an engine having a cylinder, a iston and piston-rod in the cylinexhaustion of steam to and from der, and` va ve mechanism to control the ad mission and exhaustion of steam to and from the cylinder; an independent exhaust-pipe at or near oneA end of the c linder, a valve in said exhaust-pipe normal y closed but. capa-v ble of beingopened by the pressure of steam, air or gaspassingvfrom the cylinder through the said exhaust-pipe and mechanism connecting said supplemental valve with the main-valve mechanism of the engine adapted to hold the supplemental valve closed thereby closing the independent exhaust-pipe during the time steam is workin in the portion "of the cylinder adjacent to t e exhaust-pipe.

3.' In combination with an engine having a cylinder, a iston and piston-rod in the cylinder, and va ve mechanism to control the admission and exhaustion of steam to and from the cylinder; an independent exhaust-pipe at or near one end of the cylinder, a valve in said exhaust-pipe normally closed but capable`of being opened by the pressure of steam, air or gas-passing the said exhaust-pipe and mechanism connecting said supplemental valve with the main-valve mechanism of the engine adapted to hold the supplementalvalve closed thereby closing the independent exhaust-pipe during the time -steam is Working in the portion of IIS from the cylinder through and to release the supplemental valve during the remainder of the stroke of the engine.

4. In combination with an engine having a cylinder, a iston and piston-rod in the cylinder, and va ve mechanism to control the admission and exhaustion of steam to and from the cylinder; another exhaustipe at or near one end of the cylinder, a supp emental valve mounted in the said exhaust-pi e, said valve being normally closed but a apted to be opened by the pressure of air, gas or steam passing from the cylinder. through said exaust-pi e, and a steam-pipe so connecting the supp emental valve with the main-valve mechanism that live steam holds the supplemental valve closed during the portion ofthe piston-stroke that steam is Working in the part of the cylinder adjacent to the supplemental valve.

5. In combination with an engine having a cylinder, a piston and piston-rod in the cylinder, and valve mechanism to control the admission and exhaustion of steam to and from the cylinder; an independent exhaust-pipe leading from at or near one end of the cylinder, a supplemental valve mounted in said exhaust-pipe adapted to be opened by the pressure of steam, air or gas passing rom the cylinder through said exhaust-pipe to allow said gases to escape, and a steam-pipe so connected with the supplemental valve and with' the main-valve mechanism that live-steam holds the supplemental valve closed during the time steam is working in the end of the cylinder adjacentto the supplemental valve and also so connected that said steam-pres- -der and va sure is cut ol' from the supplemental valve at or before the main exhaust-valve of the engine o ens to the same end of the cylinder.

6. n combination with an engine having a cylinder, a iston and piston-rod in the `cylinder and valire mechanism to control the admission and exhaustion of steam to `and from the cylinder; an independent exhaust-pipe at or near the one end ofthe cylinder, a differential piston-valve mounted in said exhaustpipe having its smaller area adapted to be engaged by steam, air or gas passing from the cylinder through the independent exhaust-pipe to open said valve, to permit said gases to pass out of the cylinder, and a steampipe connecting the'larger end of the differential valve with the main-valve mechanism of the engine; said connection being made at such a point that live steam is admitted to the larger end of the supplemental valve to hold it closed during the portion' of the stroke of the engine that steam is working in the end of the cylinder adjacent to the supplemental valve,

7. In combination with an engine having a cylinder, a iston and piston-rod in the cylinve mechanism to control the admission and exhaustion of steam to and from the cylinder; an independent exhaust-pipe at or near each end of the cylinder; a supple-l mental valve mounted in each of said Independent exhaust pipes; said valves being adapted to normally close said pipes and to be opened by the pressure of steam, air or gas in the end of the 'ylinder to which each supplemental valve belongs, a steam-pipe connecting each of saidsupplemental valves to the main-valve mechanism of the engine in such a way that while steam is being used for Work in one end of the cylinder the supplemental valve at that end of the c linder is held closed by steam admitted by t e mainvalve mechanism of the engine and at the same time there is no steamressure tending to close the supplemental va ve at the opposite end of the cylinder.

8. A cylinder compression relief valve comprising a casing having, in one ortion two ports or openings, one adapted to e connected to an engine-cylinder and theother for the exhaustion of steam, air or gas and in another portion a port or o ening adapted to be connected to a source o live steam, a piston-valve within the casing adapted to have one end engaged by steam, air or gas entering the valve through said cylinder-port to move said valve to open acommunication between said first two openings or orts and the other end adapted to be enga ed) by steam entering the casing through sai steam-port, to move said valve in the opposite direction to close the connection between said cylinder and exhaust ports in the casing.

9. A cylinder compression relief valve comprising a casing having in one ortion two ports or openings, one adapted to e connected to an engine-cylinder and the other for the exhaustion of steam, airor gas; and in another portion a port or opening adapted to be connected to a source of live steam; a piston-valve within the casing adapted to have one end en aged by steam, air or gas entering the valve t ough said cylinder-port to move said valve to open a communication between said first two openings or orts and the other end adapted to be engage by steam entering the casing through said steam-port, to move said valve in the opposite direction to close the connection between said cylinder and exhaust ports in the casing; the area of the piston engaged by the live steam being greater than the area engaged by the exhaust-steam.

10. A cylinder-compression relief valve comprising a casing having in one ortion two ports or openings, one adapted to e connected to an engine-cylinder and the other for the exhaustion of steam, air or gas and in another portion a port or o ening adapted to be connected to a source oi) live steam;a piston-valve within the casing adapted to have one end engaged by steam, air or gas entering the valve through said cylinder-port to move said valve to open a communication between said iirst two openings or ports and the other IOO lsaid valvein the opposite direction to close the connection between said cylinder and eX- haust ports in the casing; and means for f draining the live-steam space in said mechl anism.

114. A cylinder-compression-relief valve 'comprlsing a caslng having 1n one ortlon l 1Q .two ports or openings, one adapted to e connecte'dl to an engine-cylinder and the other for the exhaustion of steam, air or gas, and in another portion a port or opening Aadapted to beconnected'to a vSource o live steam; a piston-valve within the casing adapted to have f one end engaged by steam, airor gas entering the valve throi'lgh sai'd cylinder-portto move said valve to lopen a communication between said firsttwo openings or orts and the 'other end adapted tobe engage by steam a drainage-valve in communication with the live-l steam space in said mechanism adapted to be closed by the (pressure of steam within the mechanism an adapted to open for drainage vwhen the steam-pressure is removed.

l2. In mechanism of the class described,

the combination of a casing 60 having at one end ports or openmgls 61 and 64 communi- Yeating with each o er through the casing, and at the other end a steam port or opening 78, a piston-valve 66 having one end 68 adapted to be engaged by steam from ort orA pipe 78, and another end 67 adapte to b e lengaged by exhaust-steam in pipe 61; and

means for adjusting the length of travel of the piston 66.

' 13.-In mechanism of the class described, the combination of a casing; a piston-valve' adapted to be moved backward and forward vwithin the casingunder the action of steam admitted at either end-of the piston, and a supplemental draina e-valve larger at one end than the other, t ough the main valve adapted to be engaged by the steam at either end of the casing substantially as described for the purposes-set forth. l

In witness whereof I have hereunto subscribed my name in the .presence of two witnesses,

JOHN W. MILLER.

Witnesses:

DWIGHT B. CHEEVER,

CAROLYN RAFTERY.

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