Bbc Brown, Boveri & Company, Limited

Jaroslav Masek

Kamil Prochazka

Franz Suter

Heinrich Lageder

Arthur Oberle

Peter Heiniger

Herbert Senn

In an actuating drive for valves, the stroke motion of the servo piston has to be transmitted to the return sleeve in the control block, so that this results in that hydraulic feedback which restores the equilibrium at the servo piston. By means of a lever or a single-point mounting, this same stroke motion is directly transmitted to a pin attached in an eccentric position relative to the center axis of the return sleeve and transmitted from this pin to the return sleeve adjoining thereunder.

Return mechanism of an actuating drive

To generate a prestress between a piston rod (1) and a valve spindle (2), a bar (5) is incorporated in the piston rod (1) and is prestressed against the valve spindle (2) by exerting a pressure force, which absorbs the pulling and pushing forces occurring there.

Device for generating a prestress when two connection parts are coupled

The valve intended for direct connection to the outer casing of a double casing steam turbine has a diffusor located in the valve housing, which diffusor protrudes through the outer casing into a connection stub pipe of the inner casing, where it is connected with a flexible seal to the inner casing. In a preferred embodiment, the diffusor sits with a cylindrical step in a corresponding bore of the valve housing, the valve housing consisting of ferritic cast material and the diffusor of austenitic steel, whose coefficient of thermal expansion is greater than that of the valve housing material. The diffusor, which sits loosely in the cold condition, expands more than the valve housing when the turbine becomes hot so that the diffusor is then firmly held in the valve housing.

Valve for steam supply on double casing turbines

The electro-hydraulic actuator for turbine valves essentially includes a control valve, a rapid action stop valve, a hydraulic supply and an oil supply unit. In order to create a hydraulic actuator for turbine valves which, on the one hand, satisfies the stringent requirements with regard to adjustment force and adjustment speed and, on the other hand, avoids the problems associated with the transmission of hydraulic energy, at least one adjustment valve and at least one rapid action stop valve are allocated per turbine inlet valve. The actuators of these two valves are of the same design and are mutually interchangeable and integrated into a compact actuator unit located on the valve housing. The actuators are connected in pairs to a hydraulic supply located immediately adjacent to the actuators. In addition, the actuators are controlled by a volumetrically controlled oil supply unit integrated with the hydraulic supply, this oil supply unit containing an adjustment pump for controlling the adjustment valve and an auxiliary pump for controlling the rapid action stop valve.

Electro-hydraulic actuator for turbine valves

A safety system for a steam turbine installation is disclosed based on a closed circuit principle and includes a two-channel low-pressure section in which safety devices are utilized and a high pressure section. Each channel of the low-pressure section acts hydraulically on the high pressure section by way of a tripping and reset relay. The high pressure section includes a high pressure hydraulic system and is divided into an intermediate safety system and a principal safety system each having a two channel arrangement. A one-channel common safety system is provided with stop valves for the steam turbine. Feed and discharge amplifiers are hydraulically connected in series and separate the intermediate and principal safety systems. A separating relay is provided between the principal and intermediate safety system so that the safety devices in the low pressure section can be tested channel by channel during operation of the steam turbine with the series arrangement of the feed and discharge amplifiers being interrupted.

Safety system for a steam turbine installation

A combined stop and control valve for incorporation into a pipe carrying the working medium of a turbo-machine and in particular a steam turbine has the respective bodies of the stop and control valves arranged independently of each other in a common housing which is provided with co-axially arranged valve seats located adjacent one another at the flow opening of the valve cage. The body of the control valve has a bell-shaped configuration into the hollow cavity of which the body of the stop valve travels co-axially, and both of the valve bodies are rigidly supported in their end positions against the valve housing. The valve seat is provided with a throttle collar around which circumferentially spaced slots are distributed, the inner diameter of the collar being approximately equal to that of the control edge of the control valve body. The body of the stop valve has a conical seating surface which together with the inner circumference of the control valve body forms an annular gap tapering in the flow direction of the working medium.

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Wettingen, Switzerland

Jaroslav Masek