US1456090A - Valve mechanism - Google Patents

Description

May 22, 1923-. 1,456,090

F. s. BENNETT VALVE MECHAN I SM Filed Feb. 14 1920 Inventor: FFanKSJBennett,

I-l isAttorneng Patented May 22, 1923.

ERANK s. BENNETT, OE SOHENEOTADY, NEW YORK, AssIeNOR To GENERAL COMPANY, A CORPORATION OE NEW Yoax. l

y l y 1,456,090 PATENT OFFICE.

ELEOTRIO VALVE MECHIANISM.l

Application led February 14, 1920. Serial No. 358,733.

T 0 all 'whom t may come'm.:

Be it known that I, FRANK S. BENNE'rr, a citizen of the United States,` residing at Schenectady, in the county of Schenectady, St-ate of New York, have invented certain new and useful Ilnprovements in Valve Mechanisms, of which the followingr is'- a specification.

The present invention relates to' valve mechanisms such as are used to control the iow of elastic fluid to turbines and the like and has for its object to rovide an improved arrangement-in a device of this chara-cter.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and claims appended thereto.

In the drawing, the figure is a sectional view of a valve mechanism embodying my invention, the same being shown by way of example as embodied in a structure particularly intended for use in controlling the flow of elastic fluid to the ahead and reverse turbines or turbine sections of a marine turbine. It will be understood, however, that the invention is not limited to such a struc- Referring to the drawing, 5 indicates a valve casing having' Walls forming an admission chamber 6 and two separate discharge chambers 7 and 8. Connected to admission chamber 6 is .a supply conduit 9. and leading from discharge chambers 7 and 8 aredischarge conduits 10 and 11 respectively which may lead to separate turbines or turbine sections for supplying operating fluid thereto. The How of elastic iuid from admission chamber 6 to discharge chambers 7 and 8 is controlled by valves 12 and 12a which are shown as being of like structure. The stems 13 and 13avof valves 12 and 12a are tubular in form and at their outer ends connect to balancing pistons 14 and 145r1 which slide in cylinders 15 and 15a respec tively. The inner ends of valves 12 and 12a are guided by, sleeves 16 and 16, and

are each provided with pilot valves 17 and 17iL which engage seats on the inner ends of valve stems 13 and 13a and control the admission of operating fluid to cylinder 15 and 15a. The stems 18 and 18a ofpilot valves 17 and 17a ass through suitable stuiiing boxes 19 an 19 in the valve casing and atv their outer ends are connected to operating levers 20 and 20a which move' position.

The foregoing is a known type of valve y structure and its operation is well understood. When the valves 12 and'12 are' closed, the Huid pressure in admission chamber 9 acts on them vto hold them tightly on 'their seats, the valves being thus biased to closed position. Pilot valves 17 and 17 are also on their seats which cuts ofil communication between admission chamber 6 and cylinder 15 and 15. The -pressure in cylinder 15 and 15a behind pistons 14 and 14a will be that found in discharge chambers '7 and 8, as the pressures on opposite sides of such pistons become equalized due to gradual leakage past the pistons. In opening a valve, for example, valve 12, when the operating lever 2O is moved the pilot valve 17 Will be rst opened to admit operating fluid from chamber 9 around the pilot valve stem 18 to the balancing cylinder 15, thereby equalizing or subst-antially equalizing the pressure on valve 12, Which can then be easily opened as it will be substantially balanced. The degree of balance will depend, of course, upon the relative areas of valve 12 and'piston-lli, and by chosing pro er areas the valve when Opened may be iased slightly toward either open position or closed position.

When a valve structure of the type described above is used to control the admission of elastic Huid toa prime mover. such as a turbine, it is the practice to provide in advance'of it, as regards the flow of elastic fluid, a suitablev emergency lshut-off' valve which is biased toward closed position and is adapted to be tripped either manually or automatically as by an emergency governor and caused to close. In the drawing, such an emergency valve is indicated at 24. It is shown as being a clapper type valve adapted to engage a seat 25 and as having a spindle 26 to which is connected a lever arm 27. Connected to the end of arm 27 is an Operating rod 28 which extends to an emergency tripping mechanism (not shown). For example, such tripping mechanism may be of the type shown in the apy:so

y without danger of accident.

vplica-tion of Edgar D. Dickinson, Serial No.

'sures in admission chamber 6, discharge chamber k7 and in cylinder 15 behind piston 14 is thatyof the high pressure elastic iluid. If now, due to some cause, the emergency valve 24 is tripped and closed, then the pressures in chambers 6 and 7 will immediately drop becoming equalto that which exists at the exhaust end of the turbine, and high pressure elastic fluid will be trapped in cylinderl. and exert a heav pressure tending to open the valve. cumstances, if the operative, before the pressure has leaked out of cylinder 15, starts to close valve 12 for the purpose of aga-in startin up the machine, as soon as he releases atch 22 the pressure back of piston 14 will instantly throw the valve to wide open position with considerable force and with danger of injury to the operative. More particularly, the object of my invention is to provide an arrangement which will pre- -vent an accident of this character happenings,

and to this end I provide an equalizing pipe or'conduit '30 which connects the admission chamber 6 with the cylinders 15 and 15a, and in such pipe or conduit I provide a check valve 31 'which prevents the flow of fluid from chamber 6 to the cylinder but permits it to flow from the cylinder to chamber 6. With this arrangement it will be seen that the pressure in cylinders 15 and-'15a can never be greater thanvthat in chamber 6 and that in case the emergency valve 24 closesl under the conditions set forth above, the pressure inI cylinders 15 or l5a will be instantly relieved through conduit 30 so the operative may immediately close such valve In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof,

' but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is

l. In a valve structure, the combination of a casing having a seat, a main valve adapted to engage said seat, a cylinder, a balancing piston for the main valve, which piston is located in said cylinder, conduit means connecting the admission side `of the valve casin in said con uit means, an additional conduit. means independent of the pilot valve connecting the valve Lcasing on the admission side ofthe main valve to said cylinder.

2.*In'a valve structure, the combination of a casing having a seat, a main valve to said cylinder, a pilot valve.

adapted to engage said seat, a cylinder, ya Y balancing piston for the main valve, which piston is located in said cylinder, a pilot .valvefor the main valve, conduit means connecting the valve casing on the admission side of the main valve to said cylinder, and al non-return valve in said conduit which opens toward the valve casing.

3. In a valve structure, a valve casing having an admission chamber and a plurality of discharge chambers, a main valve between said admission chamber and each discharge chamber, a balancing piston and a pilot valve foreach main valve, conduit means controlled by said pilot valves, a

cylinder for each balancing piston, conduit means independent of said pilot valves connecting lsaid admission chamber to each of said cylinders, and check valve means in lsaid conduit means.

4; A valve structure comprising amain valve, a cylinder, 4a'balancing piston therein, and a pilot valve controlling the admission yfof fluid to the cylinder characterized by the fact that in connection with such valve structure a conduit is rovided which connects the cylinder to tllie admission side of the main valve and contains a non-return valve.which opens away from said c linder,

whereby the pressurey in the cylin er can -never exceed that on the admission side of the main valve. y

In witness whereof, I have hereunto set my hand this 12th day of February 1920.

FRANK S. BENNETT.

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