US1383005A - Steam-valve - Google Patents

Description

L. R. MERTENS.

STEAM VALVE.

APPLICATION FILED APR.24, 1920.

Patented June 28, 1921.

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UNITED STATES LOUIS R. MERTENS, OF PHILADELPHIA, 1ELNTNEYII'JV'ABTIA, ASSIGNOR T0 CHAR-LES J.

PATENT OFFICE.

MILLER, 01? PHILADELJPHILA, PENNSYLVANIA.

STEAM-VALVE.

Specification of Letters Patent.

Patented J line 28, 1921.

Application filed April 24, 1920. Serial No. 376,33 t;

valve, the valve is opened by lifting the valve stem off its seat, and the steam escapes through the annular space between the valve seat and the rim of the valve adapted to seat thereon. In this relative position of the valve and its seat, the valveand its seat are separated by such a relatively slight distance that the friction of the steam upon the adjacent parts cuts, and rapidly wears away, the opposing separated. surfaces, and

the valve soon leaks. The life of the Valve.

is hence very short and in ordinary installations it is necessary to putup with leaky valves or to assume the serious ex ense in volved infrequent replacements. to installations where it is necessary to throttle the steam flow, the space between the surfaces throu h which the steam flows is very slight indeed, and the destructive action of the steam is very pronounced.

One of the main objects of my invention is to so construct the valve that its life will be greatly prolonged. Another object of my invention is to so construct the valve that if and when it becomesso worn as to be leaky, the worn members may be replaced with a minimum of expense and trouble. Another object of the invention is to absolutely prevent a back flow of pressure fluid or other gas or liquid in case conditions arise which produce a reversal of pressure 7 in the system.

A preferred'embodiment of my invention is shown in the accompanying drawings, in which- I Figure 1 is a'vertical sectional view of a valve structure embodying my invention, the valve proper being closed.

Fig. 2 is a partial vertical sectional view of the valve structure, the (valve being slightly open.

Fig. 3 1s a detail elevation of the valve proper and its guide.

. the stem of the valve in an ordinary globe valve structure. Instead, however, of being secured to the valve it is provided, at its lower end, with a head 9 adapted to bear against the valve and hold it to its seat, as

I hereinafter explained.

The valve casing a is provided with a central horizontal web or partition h separating the valve casing into a steam inlet chamber and a steam outlet chamber communieating with: the respective ports I) and a. The web it has a central orifice through which extends the cylindrical valve guide z' having at its lower end an annular flange j.

The flange j is held against the lower wall of the web by'means of a neck is secured to a cap or closure m, threaded into an opening in the'bottom of easing a. The neck is is provided with openings 'n to allow steam to pass from the lower steam inlet chamber of the valve casing or into the interior of the valve guide 2'.

A cylindrical valve 0 extends into and is .slidable within the valve guide 71 and is closed at its top, the top being flanged to form a head p adapted to seat against a valve seat formed on'theupper end of the valve guide 2'. In Figs. 1, 2 and 3, the valve seat is formed by beveling the inner edge of the top of the valve guide at r, the overhanging part of the valve head p being cor; respondingly' beveled at s. In Fig. 4 the valve seat isformed by bevelin the outer edge of the top of the valve gui e at u, the overhanging part of the'valve head 1) being beveled correspondingly at o.

'The valve 0 has preferably a steam tight sliding fit in its guide i, but this is not essential, as hereinafter explained. It is provided in itscylindrical wall with openings t, for the passage of steam.

The valve is maintained closed by screwing down the stem 6 until its head engages the head p of the valve 0 and resses it firmly on its seat. In such position, the steam is free to flow through the port I) over the valve seat, owing to the valve head being held thereagainst.

By screwing up the valve stem e causing it tojrecede from the guide 73, the steam pressure acting against the head of the valve will cause it to follow up the stem 6. The first action will merely cause the valve to be unseated without allowing passage of steam;

I but after the valve has lifted to the extent required to lift the" upper ends of the openings 25 above the top of the valve guide, steam is free to flow into the upper chamber of the valve casing and out the port 0. The volume of steam flow will vary with the extent to which the valve 2' is allowed to lift above this-level, the maximum steam ow being permitted when the openings 6 are. entirely uncovered.

It will be observed that there is no flow of steam until the closed end of the valve has receded a substantial distance from its seat so that the friction of steam on the valve seat and on the part of the valve seated thereon is negligible. Hence the wear between the valve and'its seat is reduced'to a minimum and the life of the valve indefi nitely prolonged.

In case of any looseness of fit between the valve and its ghide, allowing a film of steam to enter between them, a slight outflow of steam will occur before the openings t begin to uncover, but even with a slight lifting of the valve, the space between its head and its seat will be substantially greater than the width of the annular space between the valve and its guide, so that any steam creeping over the seat of the valve will not have suflicient velocity to appreciably cut the valve seat,

While the life of my improved valve will thus be substantially prolonged, it has the additional advantage that, in case replacement is necessary, there is no occasion to substitute an entirely new valve structure, as in the ordinary valve, and the replacement is much more simpleand inexpensive than in the case of other known valve structures provided with removable valve seats. All that is required is to remove the bottom closure m, and the valve guide a andvalve 0' drop out. A new valve guide and valve are then inserted and the closure restored, and the valve structure is, to all intents and purposes, fully as good as if it were entirely new, there being no factors tending to wear naeapca away the valve casing, its upper and lower clojsur'es, or the valve stem.

Another disadvantage of the ordinary valve is that the valve is often placed on a line wherein a reversal of pressures is apt to develop; that is, the pressure in the steam outflow line may rise, or the pressure on thesteam inflow line may fall, so as to induce a backflow' of steam or other fluid, or liquid, with harmful or even disastrous results. With my invention, any reversal of pressures will result in an immediate closure of the valve; regardless of the position of the hand-operated separate valve stem.

It is often necessary or desirable to so porapid. wearing of the valve and valve seat occur, because, in order to slightly open the valve, the valve is lifted off its seat but very slightly, leaving a very narrow annular space for the passage of the actuating fluid. With my invention, however, it is necessary to separate the valve and its seat a substantial distance before the openings t in the valve 0 begin to uncover; so that even when the valve is throttled to its maximum extent, the valve head is lifted to a level where it cannot be injuriously affected by the flowing steam. I 1 I While my invention is more particularly intended. for use in connection with valves for controlling steam, it is obvious that it may be applied to valves for controlling the flow of any fluid, as, for example, the outflow of water of condensation from a steam flanged lower end, a closure for the bottom opening ada ted to engage the lower end of the valve guide and hold it against said web, a perforated hollow valve of smaller diameter than the orifice in the webextending into, and adapted to seat upon, said guide, and a separate stem adapted to be moved in one direction to seat the valve and in the opposite direction to allow steam pressure to unseat the valve. I 2. A steam valve comprising avalve casing having a bottom opening, an orificed web in the casing, the casing having an inlet port and an outlet port on opposltesides of said web, a hollow valve through the orifice in the we a closure for the bottom opening, an orificed neck: onthe closure adapted to engage said guide and,

gpide extending guide and adapted to seat thereon, said valve being arranged to be inserted through the bottom opening and the orifice in the web, and a separate stem adapted to be moved in one direction to seat the valve and the oppoguide resting solely on said closure and havmg a maximum diameter less than that of the bottom opening, a valve seated and suported solely on said guide, a separate stem liolding the valve on its seat but, adapted to v be retracted to allow the valve to lift off its seat, the bottom closure being removable to allow the valve and its seat to be removed through the bottom opening.

4. steam valve comprising a valve casing provided with inflow and outflow ports and having top and bottom screw threaded openings, a top closure and valve stem guide threaded into the top opening of the casing,- a turnable stem threaded in said guide and 7 extending into the valve casing, an-orificed web within the casing, a hollow valve guide open at both ends and extending through the orifice in the web and having a flanged lower end, a closure threaded into the bottom opening of the casing, a neck carried by the lower closure and adapted to engage the lower end of the guide and hold its flanged end against the web, said neck being perforated to allow flow of fluid thereinto, a hollow valve within said guide and open at its lower end to communicate with the interior of said neck and closed at its upper end, which is exteriorly I flanged and adapted to seat upon the upper end of said guide and to be heldon its seat by said stem, said flange being of less diameter than the orifice in the web, the valve being provided with perforations adapted, after the valve has been lifted by fluid pressure a substantial distance off its seat, to uncover to allow'flow of fluid from the interior of the valve to the part of the valve casing communicating with the outflow port.

In testimony of which inventlon I have hereunto setmy hand, at Philadelphia, 'Pa., on this 21st day of April, 1920.

LOUIS R. MERTENS.

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