Abstract:
A steam turbine having improved stationary parts in which a moisture removal slot (16) is formed in a blade ring (10) cylinder immediately upstream of the last row of rotating blades. The slot has a reduced width inlet throat portion (23) and an enlarged manifold portion (11). The manifold portion of the slot distributes the moisture collected to a plurality of radially oriented discharge holes (24) formed in the blade ring. The inlet throat serves to insolate the manifold from the swirling steam flowing through the turbine, thereby preventing entrainment of the moisture droplets into the steam flow. The blade ring encircles the tips (26) of the last row of rotating blades and the outer flow guide (9) is integrally formed on the blade ring.
Abstract:
A bias voltage (V alpha ) vectorially added to the controllable voltage (V?pq?) injected in series with the line voltage (V?o?) of a transmission line (3) reduces the required MVA rating for a unified power flow controller (UPFC) (1) in applications where the power in the transmission line (3) only flows in a single direction, or where the range of the transmission angle is otherwise unequal about zero.
Abstract:
The nuclear steam generator (10) has a heat transfer tube (40) surrounding a repair sleeve (160) that has been hydraulically expanded into engagement with the tube. The tube (40) and the sleeve (160) define a gap (170) therebetween having moisture residing therein. The system (180) includes an air compressor (190) in communication with the gap (170) for supplying air to the gap and a dryer (250) in communication with the air compressor (190) for drying the gas supplied to the gap. A heater (240) in communication with the air compressor may also be provided for heating the air supplied to the gap, so that the moisture residing in the gap evaporates into the heated air. A vacuum pump (290) in communication with the gap may be provided for decreasing the pressure of the heated air in the gap, so that substantially all the moisture evaporates from the gap and into the heated air.
Abstract:
A system for measuring spring pack displacement of a motor-operated valve (MOV) includes at least one power line having a current. The system includes a current sensor for sensing the current and providing a plurality of digital current values, and a personal computer (PC) processor for acquiring a plurality of frequency values of one or more frequency signatures from the plurality of digital current values and calculating the spring pack displacement from the plurality of frequency values. The processor may include data storage for the plurality of digital current values for at least a time interval necessary to stroke the valve stem in either an open or closed direction. The MOV may include a motor pinion gear having a motor pinion tooth-meshing frequency, a worm shaft having a rotational frequency, a worm shaft gear having plural teeth, a worm having a worm lead, a worm gear having plural teeth and a worm gear tooth-meshing frequency, and a spring pack having a displacement. The frequency signatures may include the motor pinion tooth-meshing frequency and the worm gear tooth-meshing frequency. The processor may calculate the rotational frequency of the worm shaft from the motor pinion tooth-meshing frequency divided by a number of the plural teeth of the worm shaft gear, the number of rotations of the worm shaft from the integral of the rotational frequency of the worm shaft, and the number of the plural teeth of the worm gear being meshed from the integral of the worm gear tooth-meshing frequency. The processor may also calculate the spring pack displacement from the product of the worm lead times the difference of the number of the rotations of the worm shaft less the number of the plural teeth of the worm gear being meshed.
Abstract:
A gas turbine stationary vane having an airfoil portion and inner (36) and outer (38) shrouds. Five serpentine radially extending cooling air passages (51-55) are formed in the vane airfoil. The first passage (51) is disposed adjacent the leading edge (40) of the airfoil and the second passage is disposed adjacent the trailing edge. A first portion (80) of the cooling air enters the first passage (51), from which it flows sequentially to the second, third, fourth and fifth passages. Additional cooling air (83) enters the third passage directly, thereby bypassing the first and second passages and preventing over heating of the cooling air by the time it reaches the fifth passage. A radial tube (45) extends through the second passage and directs cooling air through the airfoil, with essentially no rise in temperature, to an interstage cavity (70) for disc (42, 43) cooling. Fins project (60-64) into each of the passages and serve to increase the effectiveness and flow rate of the cooling air. The fins in the first and fifth passages are angled so as to direct the cooling air toward the leading (40) and trailing (41) edges, respectively. In addition, the fins in the second through fifth passages are angled to retard flow separation as the cooling air turns 180 DEG from one passage to the next.
Abstract:
A pump is provided for use in a solid state mass-spectrograph for analyzing a sample gas. The spectrograph is formed from a semiconductor substrate having a cavity with an inlet, gas ionizing section adjacent the inlet, a mass filter section adjacent the gas ionizing section and a detector section adjacent the mass filter section. The pump is connected to each of the sections of said cavity and evacuates the cavity and draws the sample gas into the cavity. The pump includes at least one piezoelectrically-actuated diaphragm. Upon piezoelectrical actuation, the diaphragm accomplishes a suction stroke which evacuates the cavity and draws the sample gas into the cavity. Preferably, the diaphragm is formed from a pair of electrodes sandwiching a piezoelectric layer.
Abstract:
An accumulator tank (60) for containing water under a pressurized, gaseous atmosphere is attached to the primary loop via a coupling, which provides an oulet for the coolant from the accumulator tank to pass to the primary loop. A valve (120), which includes a pressure sensor (150) that senses the pressure in the accumulator tank (60) and opens or closes the coolant flow in the coupling in response to the sensed pressure, is attached to the coupling. The valve causes the coolant to pass substantially through the coupling at a substantially high flow rate when the pressure in the accumulator tank is relatively high and causes the coolant to pass from the accumulator tank to the circulation loop through the coupling at a substantially low rate when the pressure in the accumulator tank is relatively low which, in turn, provides long term cooling of the reactor vessel.
Abstract:
An expandable top nozzle (1) for a nuclear fuel assembly having zircaloy thimble tubes (27) has a cylindrical barrel (3) and an assembly (11) slidable in the barrel (3) which includes a hub (13) and a thin rod ejection plate (19) fixed in spaced relation to the hub (13) by support tubes (15) through which the control rods extend. The support tubes (15) extend through the hub (13) and a spring retainer plate (35) biased against an annular shoulder (9) in the barrel by helical compression springs (45) concentrically mounted with the support tubes (15) in counterbores (41, 43) in the hub (13) and spring retainer plate (35). A centrally located instrument guide tube (57) has a spring loaded plunger (63) which extends through the spring retainer plate (35) and sets the height of an RCCA (55) below the top (5) of the barrel (3) despite expansion and compression of the nozzle (1) with changes in thimble tube length relative to the other internals. The top nozzle (1) is removably attached to a fuel assembly (29) by tubular inserts (99) fixed to the thimble tubes (27) and having collapsed fingers (15) with an annular outward bulge (107) adjacent the free end (103). With the collapsed fingers (15) inserted in the apertures (21) in the rod ejection plate (19), lock tubes (115) are pushed through the support tubes (15) to spread the collapsed fingers (15) of the inserts (99) into engagement with circumferential grooves (113) in the apertures (21).
Abstract:
A method and apparatus for cleaning and burning a coal-derived fuel gas so as to emit a minimum of sulfur and NOx by removing particulates, alkali and sulfur from fuel gas produced by the gasification of coal in a gasifier and then combusting the fuel gas in a multi-annular swirl type combustor. In the combustor, swirling compressed air serves to cool the combustor walls and provide good mixing. The combustor contains first and second combustion zones. The first combustion zone operates in a fuel rich environment so as to convert nitrogen bound in the fuel gas to molecular nitrogen. The second combustion zone operates in a fuel lean environment that completes the combustion process and rapidly quenches the products of combustion so as to reduce the conversion of molecular nitrogen to NOx. The compressed air for the combustor is pre-heated by transferring heat to it from the fuel gas produced by the gasifier.
Abstract:
A combination of elements is disclosed for use in a security access circuit (100). A first antenna (10) is embedded on a printed circuit board and a second antenna (12) is embedded on the same printed circuit board. The second antenna (12) is embedded at a position relative to the first antenna (10) selected to reduce interference between the first antenna (10) and the second antenna (12).