Asea Brown Boveri Inc.

Bbc Brown, Boveri & Company, Limited

Bbc Brown Boveri Ag

Asea Brown Boveri Ag

Abb Management Ag

Abb Alstom Power (schweiz) Ag

Kamil Prochazka

Heinz Frey

Franz Suter

Heinrich Lageder

Jaroslav Masek

Rico Plangger

The invention relates to a plate valve (,) as used for the actuator of a control valve. It comprises an inlet (,) with a sealing seat (,) around which the openings of the outlet (,) are arranged, and it has two plates (,), (,), between which there is an interspace (,). Both plates (,), (,) are attached to the housing (,) by springs (,) in a spring space (,). The spring space (,) is operatively connected to a proportional valve by an opening (,) and a line (,). If the pressure in the spring space (,) is lowered by the proportional valve, the additional plate (,) first of all drops as a result and thereby exposes the outflow openings (,) in the large plate (,). There is a slight flow of the oil from the inlet (,) through the orifice plates (,) situated in the plate (,) and through the outflow openings (,) to the openings of the outlet (,). In a second stage, the plate (,) then drops and thereby exposes the openings of the outlet (,). The plate valve (,) is open and the oil can flow unhindered from the inlet (,) to the outlet (,). The plate valve (,) is suitable for an actuator, the control valve of which is to have a short closing time since it has good dynamic characteristics by virtue of its configuration with two plates (,), (,).

Plate valve

This actuating drive (1) for a control valve (2) has a control circuit which sets the actuating drive (1) to correspond with a specified required value from an overriding installation control system. It has, in addition, a main piston (6) sliding in a main cylinder (5) with a drive volume (7), on one side of the main piston (6), which can be acted on in a controlled manner by oil under pressure and has a plate valve (17) fitted upstream of the drive volume (7). The intention is to create an actuating drive, for a control valve, whose dynamic behavior can be improved by relatively simple means. This is achieved by the plate valve (17) being provided with a separate reservoir volume, connected to a drain appliance, for the oil emerging from the plate valve (17).

Actuating drive for a control valve

This operating mechanism for a hydraulic actuator (2) having a pressure-proportional actuating signal is provided with an amplifier (33) for electric signals, with at least one electrohydraulic transducer (24) connected upstream of the hydraulic actuator (2) and with a hydraulic discharge amplifier connected between the electrohydraulic transducer (24) and the actuator (2). The aim is to provide an operating mechanism for a hydraulic actuator having a pressure-proportional actuating signal which can be produced simply and cost-effectively. This is achieved by interconnecting between the actuator (2) and the hydraulic discharge amplifier a piston/cylinder arrangement (4) acting as a transducer.

Operating mechanism for a hydraulic actuator having a

A supply circuit for a hydraulic fluid system has at least one pressure generation device, at least one connecting valve, a main line and a safety deactivation unit. The supply circuit permits a hydraulic fluid to be fed in such a way that, in all operating states, occurrence of pressure surges in the system is prevented. The connecting valve is designed as a slide valve with three control edges for regulating filling, operation and testing functions. A plate valve, in fluid communication with the slide control valve, is designed as an outflow amplifier and fulfills the safety related tasks.

Supply circuit for a two-tube hydraulic system

This actuating drive (1) has a main piston (4) which can be operated by means of an oil pressure and a pilot control system in effective connection to the main piston (4) by means of a linkage (15). The pilot control system includes a control orifice (14) controlling the oil pressure at the main piston (4) and a pilot control piston arrangement (18) which can be operated hydraulically. The actuating drive (1) is to be designed in such a way that it has improved dynamic characteristics during operation. This is achieved by the fact that the pilot control piston arrangement (18) can be operated by means of an electrohydraulic valve which is triggered by an electronic control unit (31).

Actuating drive

An actuator for a control valve with a control circuit has a main piston which slides in a main cylinder. On one side of the main piston, there is arranged a drive volume, which can be pressurized with oil in a controlled manner, on the other side of which there is arranged an oil-filled buffer volume. The actuator despite having a greater capacity, has a comparatively high dynamic performance which has positive effects particularly when closing the control valve. This is achieved in that the drive volume and the buffer volume can be connected through a connecting line which can be sealed off by a valve. This valve is activated directly hydraulically via a second valve.

Actuator

This hydraulic actuator has a drive volume (11) pressurized by extreme-pressure oil. The oil pressure is converted into a valve movement by a drive piston (10). A spring element acts upon the drive piston (10) in a manner opposing the oil pressure. The actuator is to be constructed such that extreme-pressure oil escaping from the drive volume (11) cannot cause any consequential damage. This is achieved in that the drive volume (11) is completely surrounded by a safety volume (3, 7) filled with low-pressure oil.

Hydraulic valve actuator

The switch element for triggering a cut off or control function is accommodated in a shaft (1), for example of a speed monitor. A spring-loaded release bolt (2) is surrounded coaxially by a compensating bush (4) which has a compensating ring (15), a spring plate (13) and a hub tube (14) and the center of gravity (S.sub.Kb) is such that, when the shaft (1) rotates, it compensates the centrifugal force, acting as an additional force to the spring prestressing force, of the spring half adjacent to the spring plate (13) and having the center of gravity (S.sub.F/2).

Spring-loaded centrifugal switch element

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

In a spring suspension of an actuating piston, essentially consisting of a spring plate, a control spring acting on the spring plate and a nut as connection between actuating piston and spring plate, an intermediate underlay (5) is arranged between spring plate (2) and nut (4). The supporting surfaces of the intermediate underlay (5) with respect to the spring plate (2) and the nut (4) are formed by several mutually offset rolling elements (6a, 6b).

Sprung suspension of an actuating piston

A valve actuator is disclosed having a servo-motor which regulates the position of a main valve that controls steam supply to a turbine. A hydraulic input signal acts on a pilot valve within the valve actuator body to move a valve spool in response to the input signal. Movement of the valve spool permits oil to flow into a cylinder in which the servo-motor is located. The flow of oil into the cylinder causes a piston which is a part of the servo-motor to move upwardly. Movement of the servo-motor is regulated by a cam and follower arrangement which transfers the motion of the servo-motor to a valve sleeve. The valve sleeve, which has a differential piston area, shuts-off the supply of oil to the servo-motor. The cam and follower arrangement provides for a linear correlation between the hydraulic input signal and the operation of the servo-motor. Increased closing forces provided by the differential piston reduce vibration of the valve sleeve and the servo-motor.

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Windisch, Switzerland

Kamil Prochazka