US2389074A - Turbine apparatus - Google Patents

Description

Nov. 13, 1945. s NEWTON 2,339,974

TURBINE APPARATUS Filed Sept. 27, 1943 lNVENTOR JOHN S. NEWTON.

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ATTORNEY Patented Nov. 13, 1945 TURBINE APPARATUS John S. Newton, Drexel Hill, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 27, 1943, Serial No. 503,953

4 Claims.

,mechanism for the latter.

A further object of the invention is to provide a partial peripheral admission turbine having full power valves for a group of full power nozzles, fractional power valves for separate groups of fractional power nozzles, and a separate valve, which, when closed, isolates the full power nozzles and, when opened, provides for motive fluid being supplied to the full power nozzles if the full power valves are open, together with governor-operated means for opening and closing the full and fractional power valves, the arrangement being such that, with movement of the governor-operated means in one direction, the full power valves open in succession followed by successive opening of the fractional power valves and, with movement of the governor-operated means in the other direction, the valves close in the reverse order.

In certain cases, particularly for high speed ships, it is desirable to obtain steam rates at from percent to percent of rated power nearly as good as the full power steam rates. To effect operation at full power speed, steam is admitted by nozzles having unity expansion ratio; and to obtain good steam rates at speeds below 80 percent of full power speed, admission occurs through fractional power nozzles having a higher expansion ratio. One fractional power valve and the associated fractional power nozzle group provides for operation of the turbine at cruising speed, and the other fractional power valve and its nozzle group provides medium speed operation. The mechanism for operating the valves opens the full power valves first, followed by opening of the cruising and medium speed valves; however, with the additional valve arranged between the full power valves and the full power nozzles, opening and closing of the full power valves has no effect unless the additional valve is open. With an electric drive, the arrangement has the further advantage of limiting the steam flow during maneuvering, which prevents the machine from becoming electrically disconnected. Accordingly, a further object of the invention is to provide a turbine having this governor-controlled valve arrangement and used for propelling a ship electrically.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. l is. a plan View of a propulsion arrangement showing the invention applied thereto;

Fig. 2 is a detail sectional view taken along the line IIII of Fig. l, and

Figs. 3, 4 and 5 are nozzle vane sectional views.

In the drawing, there is shown a partial peripheral admission steam turbine It connected by an electric drive to the propeller H, the electric drive conventionally employing a generator l2 driven by the turbine and connected electrically to the motor l3 driving the propeller.

The initial stage of the turbine has a full load nozzle group I5 and two or more partial load nozzle groups, for example, partial load nozzle groups I6 and I7. Steam is supplied from the steam chest I8 to the nozzle groups at l5, l6 and H, by the passages to, 20 and 2|, respectively, the passage I9 opens into the steam chest 18 through the valve seats 22 and 23 and the passages 20 and M open into the steam chest through valve seats 24 and 25, respectively, all of the valve seats being carried by the bottom wall 26 of the steam chest.

Full power valves 28 and 29 cooperate with the seats 22 and 23 and fractional power valves 3i! and 3| cooperate with the seats 24 and 25.

The valves 28, 29, 30 and 3i have stems 32, 33, 34 and 35 loosely fitting openings in the lifting bar 36 and provided with abutments 36, 31, 38 and 39, respectively, arranged above the bar, the abutments being arranged at varying distances above the valves so that the full power valves 28 and 29 may be opened in succession by upward movement of the bar, followed by opening of the partial load valves 30 and 3| and, with the valves open and with downward movement of the bar, the valves close in the reverse order. An additional valve 40 is arranged in the passage l9 between the full power valves 28 and 29 and the full power nozzles, at [5, the passage l9 having a wall 4| extending thereacross and provided with an opening 42 which is opened and closed by the Valve 40. Preferably the valve 40 is opened and closed manually b any suitable means, for example, the handwheel 43.

As shown, the bar 36 is raised and lowered by means of a governor-operated mechanism, including the rods 45 operated by the governor 46 which is connected to the turbine Ill.

The full power nozzle group, at 15, includes a plurality of nozzle vanes 48 defining nozzle passages having unity expansion ratio in order that the turbine may be fully supplied with steam for full power when the valves 28 and 29 are open. To obtain good steam rates, the partial load nozzle groups, at It and I1, each include nozzle vanes 50 and defining nozzle passages of larger expansion ratio. Figs. 3, 4 and 5 show in a somewhat exaggerated manner the relation of expansion ratios of the nozzle passages of the nozzle groups, at 15, I 6 and 11, respectively.

With the arrangement of valves and operating mechanism shown, operation of the turbine may be restricted to partial loads b closing the valve 40, the valves 30 and 3| being opened and closed successively. On the other hand, the turbine may be operated at full load by opening and closing the full load valves 28 and 29 in succession, these valves being capable of being opened and closed by the bar 36 with the partial load valves 30 and 3! closed. Therefore, good performance is had at fractional loads as well as at full load. Furthermore, as the steam fiow is limited by the arrangement when maneuvering, disconnection of the electrical machiner is minimized.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What is claimed is:

1. In a turbine of the partial peripheral admission type, a group of full power nozzles, a plurality of groups of fractional power nozzles, each of the fractional power nozzles having an expansion ratio higher than each of the full power nozzles, full power valve or valves, a passage for conducting motive fluid from the full power valve or valves to the group of full power nozzles, fractional power valves, passages for conducting motive fluid from the latter valves to the fractional power nozzles, means movable in one direction first to open the full power valve or valves and then to open the fractional power valves in succession and movable in the opposite direction to close the valves in reverse order, a partition intercepting the full power passage and having an opening providing for flow of motive fluid through the passage from the full power valve or valves to the full power nozzles and a manually-operable valve cooperating with said opening and operative to interrupt the flow of motive fluid through the full power passage regardless of operation of said means and consequent opening and closing of said full and fractional power valves.

2. In a turbine of the partial peripheral admission type, a steam chest; a group of full power nozzles; a plurality of groups of fractional power nozzles; each of the fractional power nozzleshaving an expansion ratio higher than each of the full power nozzles; passages for connecting the respective nozzle groups with the steam chest; valve seats formed in one wall of the steam chest and through which the passages open; valves cooperating with said seats; a bar movable, in one direction from a position with all the valves closed, first to open the full power valve or valves and then to open the fractional power valves in succession and movable, in the opposite direction with all the valves open, to

Iclose the latter in reverse order; ,a wall extending across the passage connecting the full power nozzles to the steam chest and having an opening forming a part of such passage; and an additional valve cooperating with the last-named opening and operative to interrupt the supply of steam to the full power nozzles regardless of movement of said bar and consequent opening and closing of said full and fractional power valves.

3. The combination as claimed in claim 2 with a governor for moving the bar and operative by the turbine. 7

4. The combination as claimed in claim 2 with means accessible externally of the turbine for manually opening and closing the additional valve.

JOHN S. NEWTON.

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