Patent GB-190827335-A (GB)
Title: Improvements in or relating to Steam or Gas Turbines.
Filed: 1908-12-16
Granted: 1909-04-01
Abstract: 27,335. Krupp Akt.-Ges. Germaniawerft, F. Feb. 26, [date applied for under Section 91 of Patents &c. Act, 1907]. Elastic-fluid turbines.-The main throttle valve of an elastic-fluid turbine is under the control of a centrifugal governor and an emergency stop gear, both mechanisms acting through the medium of a single pressure-fluid relay. The pressure of the fluid on the underside of the piston actuating the throttle valve is varied by valves controlled by the governor, and the upper side is subjected to full pressure only when the emergency gear acts. Figs. 1 and 2 show the general arrangement of the governor N, the emergency gear Q, the combined valves H, J actuated by them in the relay circuit, and the throttle valve C which controls the flow of steam from the steam-pipe b<2> to the pipe b<1> leading to the turbine A. The valve stem C<1> of the throttle valve carries a spring-pressed actuating- piston C<2> working in a cylinder E<1>. The working fluid for this cylinder is preferably lubricating-oil under pressure supplied from an air chamber reservoir U, which is charged by a pump T on the governor shaft n'. During normal working, the underside of the piston is acted on by high-pressure fluid supplied by a pipe G<3> from the valve H, and the upper side is supplied by a pipe G<4> with oil at exhaust pressure. If the governor fails to act and the emergency gear comes into operation to close the throttle, the valve J reverses the connexions so that the upper side receives high-pressure oil and the lower side oil at exhaust pressure. The valves H, J are arranged in a single casing and have their axes at right-angles tu one another. Figs. 5 and 6 show vertical sections of the valve H, and Fig. 7 shows an horizontal section of the valve J. Normally, oil passes from the reservoir by a pipe G<2> to the interior of the valve J, Fig. 7, and thence to the interior of the valve H by a passage h<3>. When the speed decreases, the governor depresses the rod k<2> and the piston uncovers the port h<1>, thus allowing more oil to pass by the pipe G<3> to the underside of the piston C<2>. When the speed increases, the port h' is put into communication with the low-pressure or exhaust pipe G<5>, and oil runs from beneath the piston C<2>. The pipe G<4> leading from the upper side of the piston communicates with the exhaust G<5> by way of a port m<4>, Fig. 7, a passage m, Figs. 5 and 6, underneath the valve J, and a port m<5>. The emergency gear, on coming into operation, moves the rod f<2> in the direction of the arrow X until the piston F<1> covers the port m<4> and the piston F covers the passage h<3>. High-pressure oil then passes from the pipe G<2> to the top of the piston C<2> by the pipe G<4>, and the oil beneath the piston runs away to the exhaust G<5> by the passages h<1>, m<2>, m<1> and the port m<3> which communicates with the passage m. The throttle valve C is closed no matter what position the governor-controlled piston may occupy. The turbine may be strapped quickly by arranging a valve, to be opened to spoil the condenser vacuum by the movement of the rod f The governor shaft n<1> is driven from the main shaft by worm gearing. The lever P, which is connected to the rod k<2> with a certain amount of play, is pivoted to the throttle-valve stem C<1>. The emergency gear Q, shown in section in Fig. 4, comprises a bolt Q<2>, q<3> adapted to move against the action of a coiled spring Q' under the influence of centrifugal force. At an abnormal speed, the lug q<5> engages the end S' of a spring-pressed lever and releases the notched end S from engagement with an arm r3 on a shaft R'. A similar arm r<2> on the other end of the shaft R' bears against the spring held rod R, Fig. 2. The rod R is immediately forced out by the spring and moves the rod f<2> to which it is connected, thus bringing about the closing of the throttle valve.