US992350A - Balanced valve. - Google Patents

Description

W. F. GOULD.

BALANCED VALVE;

APPLICATION IILED MAY 19, 1909.

Patented May 16, 1911.

WILLIAM F. GOULD, OF DES MOINES, IOWA.

BALANCED VALVE.

Specification of Letters Patent. Patented May 16, 1911.

Application filed May 19, 1909. Serial No. 496,893.

To all whom it may concern:

Be it known that I, WILLIAM F. GOULD, a citizen of the United States, residing at Des Moines, in the county of Polk and State of Iowa, have invented a certain new and useful Balanced Valve, of which the following is a specification.

In many of the slide valves used n steam engines, the valve seat on the cylinder 1s raised and the valve travels beyond the end of the valve seat, thus permitting the steam in the steam chest to press outwardly from the cylinder on the portion of the valve that projects over the valve seat, thus necessitating the application of a corresponding steam pressure on'the outer surface of the valve 1n order to balance the valve.

My invention relates to that class of balanced valves in which a valve cover is used to keep the steam pressure from the outer face of the valve.

My object is to provide a balanced valve of this class in which the pressure upon the valve is equalized during the greatest possible portion of its stroke, wholly by back steam pressure from the induction ports of the cylinder and to balance such portions of the valve as project over the valve seat, wholly by steam pressure direct from the interior of the steam chest, that is to say, so long as the valve is positioned between the ends of the valve seat, there will practically be no steam pressure from the interior of the steam chest exerted on either face of the valve, but the valve will be balanced by the steam pressure from the steam induction ports of the cylinder and when the valve projects over either end of the valve seat, the part that projects will be balanced by the pressure of steam in the interior of the steam chest.

A further object is to provide a valve of this kind having on each end a steam chamber extending completely around its outer face and to provide means for introducing steam into said chamber from openings formed in the engine valve seat and communicating between the induction ports and the said chambers when the valve is in certain positions.

A further object is to provide improved means for compensating for wear on the ends of segmental packing bars on valves of this kind, whereby steam tight joints are maintained after the ends of the packing bars have become worn.

A further object is to provide means for introducing steam underthe packing bars of a valve of this kind for the purpose of in creasing the steam pressure upon the outer surface of the valve.

A further object is to provide improved packing devices for preventing the escape of steam from the ends of the steam chambers on the valve toward the side edges of the valve.

My invention consists in the construction, arrangement and combination of the various parts of the device and the arrangement of the passageways and chambers thereof, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, in which Figure 1 shows a detail, perspective view of the valve proper in an inverted position. Fig. 2 shows a central, sectional, longitudinal view of a valve, a steam chest and a portion of an engine cylinder embodying my invention. Fig. 3 shows a detail view, partly in section, illustratinga portion of the valve and one of the segmental packing bars and the device for preventing the espjape of steam past the end of the packing Referring to the accompanying drawings, I have used the reference numeral 10 to indicate the portion shown of the engine cylinder. Formed on the engine cylinder is a raised valve seat 11 and through the central portion of the valve seat is an exhaust opening 12 and adjacent thereto are two induction ports 13. The steam chest is indicated by the numeral 1 1 and is of the ordinary construction. Contained within the steam chest is a valve cover 15, segmental in cross section and having webs 16 extended transversely across its ends. This valve cover is intended to have a slight movement within the steam chest and to provide for limiting this movement, I have placed on the ends of the valve cover, the lugs 17 to stand adjacent to the ends of the steam chest. In the outer portion of the steam chest are the set-screws 18 -to project through the steam chest and to engage the valve cover to limit its movement away from the valve seat. The parts previously described are all of ordinary construction and a further detail description thereof is deemed unnecessary.

The valve proper comprises two segmental ends 19 connected by a central tube 20 for receiving a valve stem 21 and also by the valve sides 22, the central portion of the valve being left open, as clearly shown in Fig. 1.

Each end of the valve is provided with two packing bar grooves 23 in its outer face extending from one side to the other. In each of these grooves is a spring metal packing bar 24 with its ends flush with the lower side edges of the valve. The outer edges of these bars project from the outer sur face of the valve and thus form a steam chamber in each end of the valve between the packing bars. I preferably make the area of this steam chamber substantially the same as the area of the adjacent induction port of the engine cylinder. In this connection it is to be noted that the side edges of the valve and the ends of the packing bars all rest upon the valve seat outside of the induction port opening therein. As the valve is operated there will be more or less wear upon the ends of the packing bars and after a considerable amount of wear takes place, there will be a leakage of steam from the steam chamber at the end of the valve.

To avoid this, I have provided a suppleend is flush with the end of the packing bar; its outer face is curved on the same line as the adjacent face of the main packing bar, and it rests in a small groove 23 provided for it in the valve adjacent to the face of the packing bar nearest the steam chamber in the valve. The pressure of steam upon it tends to hold it firmly to the valve seat and against the valve cover so that as the packing bar wears, this supplemental packing bar will move toward the valve seat and thus always maintain a steam tight joint. The main packing bar is always held to its outer limit and to firm engagement with the valve cover on account of the steam that will enter the groove into which it is placed, so that a leakage of steam never occurs, except around the ends of the packing bars when they have become worn oif. The supplemental packing bars 25 prevent the leakage at this point.

In the sides 22 of the valve a short distance from the inner faces thereof, I have provided packing bars 26 extending from the inner packing bar 24 at one end of the valve to the corresponding packing bar at the other end thereof, thus preventing the leakage of steam around the sides of the central portions of the valve.

So long as the end packing bars 24 are above the valve seat and until part of said packing bars project over the valve seat, I

balance the valve wholly by means of the steam pressure obtained from the induction port of the engine opposite from the one that is admitting steam to the engine, and for this purpose, I have provided in each induction sort a aassa ewa 27 communieating with the interior of the induction port, below thevalve seat, and also with the outer face of the valve seat where said passageway will communicate with the steam chamber between the packing bars on the end of the valve when said steam chamber is directly over said passageway 27. In Fig. 2 of the drawings, neither of these passageways 27 is in communication with the steam chambers on the valve because the induction port to the left of the figure is taking steam from the steam chest and the one to the right is in communication with the exhaust port 12 through the opening in the center of the valve. Obviously, when the valve moves to position with the steam chambers over the ports 27, the valve will be balanced by steam pressure from the port, for the reason that the outward pressure upon the under surface of the valve, extends over an area substantially the same as the steam chambers on the outer face of the valve which are filled with steam under the same amount of pressure as are the induction ports, because they are in direct communication with said induction ports through the passageways 27 Therefore, at all times when there is an outward pressure on the valve from the induction ports, this pressure is balanced and when there is no pressure within the induction ports, the supply of steam to the chambers on the ends of the valve is cut off. In this connection, I have provided for enlarging the capacity of the steam chambers on the ends of the valves in the event that there is not enough pressure on the outer surface of the valve to hold it to its seat, as follows:

A passageway 28 is formed to communicate at one end with the steam chamber between the packing bars on one end of the valve and at its other end with the groove 23 in which the inner packing bar 24 is placed. A screw 29 is provided in said passageway which may be removed when it is desirable to utilize the passageway. Assuming that the screw is removed, then obviously steam may enter under the packing bar 24 and thus increase the effective area of the steam chamber.

As stated at the commencement of the specification, in some instances valves travel a considerable distance beyond the valve seat at each end of the stroke. Obviously, the portion of the valve that projects over the seat has an outward pressure applied to its under surface which is not balanced, because the packing bars on the outer face of the valve do not permit the steam to bear in acorresponding degreeupon the outer face of the valve. I have, therefore, pro vided meansrfor introducing steam from the steamchest into the steam chamber on the outer face of the end of the valve which projects beyond the valve seat, to balance this outward pressure upon the valve,-as follows:- On the under face of the valve, near the end thereof, I have formed a. steam chamber 30 with passageways 31 at its ends extending to the sides of the valve and;

communicating with the steam chamber between the packing bars 24. lVhenthe end of the valve projects beyond the valve seat, steam is admitted from the steam chest into the chamber 30 and passes through the.

tinuous body of steam completely surroundmg the valve, thus more perfectly balancing it than would be possible otherwise, and by having a portion of said chamber 30 projected under the end packing bar 24, steam will be admitted from the port 13 for balancing purposes throughout a maximum portion of the valve stroke.

In practical use, it is obvious that so long as the valve is positioned wholly on top of the valve seat, there is no steam pressure upon it, except the back pressure from the cylinder through the induction port that is not admitting steam to the engine and hence it is only necessary to balance the valve against this port pressure. Therefore, the port 27 and the steam chamber between the packing bars 24: are so arranged that at all times when there is an outward pressure upon the valve from the induction port, a column of steam from the induction port and under the same pressure as the steam within the induction port, will be provided to completely encircle the valve, within the chamber formed by the said packing bars, which chamber equals the area of the steam induction port of the cylinder, so that the valve will be equally'balanced against this pressure from the steam induction port. In the event that the valve should project over either end of the valve seat, then the under surface of it will be subjected to steam pressure within the steam chest, but the outer face of the valve would not have a corresponding steam pressure on account of the valve' cover. Therefore, I have provided the steam chamber 30 soarranged anddisposed that as soon as any material part of I the-valveproj'ects over the valve seat, then steam will bead-mitted from the steam chest into the chamber 30 and fromthence to the passageways 31 to the chamber between the packing bars 24cm theouter surface of they valve and, therefore, a body. of steam will completely encircle'the endof the valve, which steam is all under the same pressure, that is, the pressure within the steam chest. In this way the valve-is balanced during its progress across the valve seat, sometimes by the back pressure from the steam induction port of'the cylinder. and sometimes by the pressure withinthe steam chest, as the nature of the case demands for balancing the valve, inasmuch as the back pressure from the cylinder varies. materially under different conditions and the steam pressure within the steam chest also varies and differs from the'back pressure of the cylinder. It is obvious that the valve will'be properly balanced againstthevarious degrees of pressure to which it is subjected.

One of the desirable .features attained by .the use of the steam chamber 30 on the under surface of the valve, is that when said steam chamber extends only part way over the induction port, the steam pressure from the induction port--will pass through the chamber 30 and through the passageway 31 into the chamber 19 on the outer surface of the valve, and there will therefore be a considerable pressure in this chamber on the outer surface of the valve tending to hold thevalve toward its seat. In order to properly balance the valve, this pressure must be overcome, hence I make the steam chamber 30 of such area that the pressure of steam within it tending to hold the valve away from its seat will substantially counter-balance the pressure before described in the chamber 19.

Obviously, if there were no chamber on the under surface of the valve, and means were provided for admitting steam from the induction port to the chamber on the outer surface of the valve, before the valve completely covered the induction port, then the pressure on the outer surface of the valve would be greatly in excess of the pressure on the under surface of the valve and the valve would not be balanced.

I claim as my invention:

1. The combination of an engine cylinder having induction and exhaust ports, a steam chest, a valve cover, a valve under said cover, steam chambers formed on the end portions of the outer face of the valve, said engine cylinder provided with passageways extending from the sides of the induction ports out- 'wardly and to the valve seat to provide communication between the induct-ion portsv of the cylinder and the said steam chambers when the steam chambers are adjacent to the induction ports.

2. The combination of an engine cylinder having a valve seat formed with induction and exhaust ports, a valve thereon having steam chambers at its ends extended across the outer face of the valve and the sides of the valve to the said valve seat on opposite sides of the induction ports, a valve cover,

said engine cylinder formed with passageways extending from the induction ports to the valve seat to communicate with the ends of said steam chambers.

3. The combination of a slide valve, a packing bar extended across the outer face thereof, said valve formed with a passageway extending from the outer face of the valve to a point beneath the packing bar, and means for closing said passageway.

4. The combination of an engine cylinder having a valve seat and induction and exhaust ports, a slide valve having at each end a steam chamber completely encircling the valve, and packing bars at the sides of the chambers on the outer face of the valve, the edges of the chambers on the under surface of the valve extending beneath the outer ones of the packing bars on the outer face of the valve.

5. The combination of an engine cylinder having a valve seat and induction and exhaust ports, a slide valve having at each end a steam chamber completely encircling the valve, packing bars at the sides of the chambers on the outer face of the valve, the edges of the chambers on the under surface of the valve extending beneath the outer packing bars on the outer face of the valve, and the edges of the chambers under the valve adjacent to the center of the valve arranged approximately below the central portions of the chambers on the outer faces of the valves.

6. The combination of a slide valve, a valve cover, steam chambers formed on the outer face of the valve between the valve and cover, steam chambers formed on the inner face of the valve and means for admitting steam from the induction ports of an engine to the chambers on both the outer and inner faces of the valve, said steam chambers on the under surface of the valve having their side edges arranged nearer the end of the valve than the side edges of the chambers on the outer surface.

7. The combination of a slide valve, a valve cover, steam chambers formed on the outer face of the valve between the valve and cover, steam chambers formed on the inner face of the valve and means for ad mitting steam from the induction ports of an engine to the chambers on both the outer .and inner faces of the valve, said steam chambers on the under surface of the valve having their side edges arranged nearer the end of the valve than the side edges of the chambers on the outer surface, and passageways formed in the valve communicating between the chambers on the outer and inner faces.

8. The combination of an engine cylinder having a valve seat, a steam chest, a slide valve, a valve cover therefor within the steam chest, said valve formed with steam chambers on the outer surface of its ends, means for alternately introducing steam into said steam chambers from the steam induct-ion ports during the times that each chamber or any portion thereof is directly over the said steam induction ports of the cylinder, said chambers being closed against the admission of steam from the induction ports when in other positions, and means for introducing steam to said chambers from the steam chest when said chambers project over the valve seat.

9. An engine cylinder having induction and exhaust ports, a slide valve, a steam chest, a valve cover, steam chambers formed on the ends of the valve between the valve and the valve cover, means for alternately providing communication between the induction ports of the cylinder and said steam chambers, when the said chambers are in position over said ports, and means for providing communication between the steam chest and said steam chambers when the valve is in other positions.

10. The combination of an engine cylinder having induction and exhaust ports and a valve seat, a slide valve thereon, a steam chest, a valve cover, steam chambers formed on the end portions of the valve between the valve and the valve cover, and having bottoms upon which the steam may operate to force the valve toward the seat, a steam chamber formed on the under surface of the valve and in communication with the steam chamber on the outer surface, said steam chamber on the under surface projecting over the end of the valve seat when the valve is at the end of its stroke.

11. The combination of an engine cylinder having induction and exhaust ports, a steam chest, a valve cover, a valve beneath the cover, packing bars extended across the ends of the valve and forming, with the valve cover, steam chambers at the ends of the valve across its outer face, and having bottoms upon which the steam may operate to force the valve toward the seat, means for introducing steam into said chambers from the induction ports when the valve is in certain positions and from the steam chest when the valve is in other positions.

12. The combination of a valve cover, a slide valve having solid ends each formed with a steam chamber on its outer face to receive steam tending to press the Valve toward its seat, and a steam chamber on its inner face to receive steam that will force the valve away from its seat, and means for providing communication between said chambers, said means so arranged that When the inner steam chamber is only partially over an engine induction port, the steam pressure from said port Will be exerted on the full area of said inner chamber, and it will also be exerted on the outer chamber and thereby counter-balanced.

Des Moines, Iowa, April 20, 1909.

WILLIAM F. GOULD.

Witnesses:

N. M. TAYLOR, M. B. GOLDIZEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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