Bbc Brown, Boveri & Company, Limited

Arthur Oberle

Jaroslav Masek

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.

Combined stop and control valve

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. The body of the stop valve has a bell-shaped configuration into the hollow cavity of which the body of the control valve is inserted. Axial guides are provided for the stop and control valve bodies and the stop valve is situated ahead of the control valve when viewed in the flow direction.

A combined stop and control valve for turbine installations and in particular a steam turbine in which the bodies of independently operable stop and control valve components are arranged co-axially to one another in a common housing. The stop valve body has a bell-shaped configuration terminating in an annular seating surface and includes a servo piston component operating in a cylinder and an associated pilot valve for controlling steam entry into the cylinder from the steam chamber. The control valve body includes a bulb-shaped head connected to one end of a spindle, and the other end of this spindle terminates in a servo piston component operating in a cylinder and an associated pilot valve for controlling steam entry into the cylinder from the steam chamber by way of a longitudinal bore through the spindle and valve head.

A control system for a nuclear power plant which comprises a boiling-water reactor and a steam line including a control valve therein connecting the steam outlet from the reactor to a steam turbine includes a first controller of the 'I-action' type responsive to the reactor pressure and a second controller of either the 'P-action' or 'PD-action' type responsive to the pressure in the steam line immediately in advance of the control valve. A summing device is provided for adding the output signals from the two controllers, and the output from the summing device is applied to the control valve for regulating its operation. For a system wherein a pair of steam lines each including a control valve therein are connected in parallel from the reactor steam outlet to the turbine, transducers are provided for measuring the respective pressures in the steam lines and a second summing device is connected to the outputs from the transducers for determining the mean value of the respective pressures in the steam lines. The output of the second summing device is then connected to the input of the second controller.

Control system for a boiling-water nuclear power plant

A steam turbine installation includes a safety system located in the steam flow path having a stop valve located in the steam flow path upstream of the turbine and a vacuum break valve located in the stream flow path downstream of the turbine, and a combined regulating and safety device connected to the turbine produces signals for controlling these valves. In addition, a signal from a steam flow monitor located downstream of the stop valve is supplied to a logic system, this signal having a value which normally corresponds to the setting of the stop valve. In the event of a disparity the logic system functions to trip the regulating and safety device which results in a closure of the stop valve and a partial opening of the vacuum break valve. Upon detection of a further mass flow by the steam flow monitor after the partial vacuum condition has been reached the logic system functions to move the vacuum break valve to full open position and activate a water injection valve that sprays cooling water on the last rows of the low pressure blading of the turbine.

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Ennetbaden, Switzerland

Arthur Oberle