EP0127027B1 - Electro-hydraulic actuator for turbine valves - Google Patents

Electro-hydraulic actuator for turbine valves Download PDF

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Publication number
EP0127027B1
EP0127027B1 EP84105238A EP84105238A EP0127027B1 EP 0127027 B1 EP0127027 B1 EP 0127027B1 EP 84105238 A EP84105238 A EP 84105238A EP 84105238 A EP84105238 A EP 84105238A EP 0127027 B1 EP0127027 B1 EP 0127027B1
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EP
European Patent Office
Prior art keywords
hydraulic
valve
valves
electro
control valve
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Expired
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EP84105238A
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German (de)
French (fr)
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EP0127027A1 (en
Inventor
Jaroslav Masek
Franz Suter
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BBC Brown Boveri AG Switzerland
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BBC Brown Boveri AG Switzerland
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/18—Combined units comprising both motor and pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/10—Final actuators
    • F01D17/12—Final actuators arranged in stator parts
    • F01D17/14—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits
    • F01D17/141—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of shiftable members or valves obturating part of the flow path
    • F01D17/145—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of shiftable members or valves obturating part of the flow path by means of valves, e.g. for steam turbines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/20—Devices dealing with sensing elements or final actuators or transmitting means between them, e.g. power-assisted
    • F01D17/22—Devices dealing with sensing elements or final actuators or transmitting means between them, e.g. power-assisted the operation or power assistance being predominantly non-mechanical
    • F01D17/26—Devices dealing with sensing elements or final actuators or transmitting means between them, e.g. power-assisted the operation or power assistance being predominantly non-mechanical fluid, e.g. hydraulic
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/87917—Flow path with serial valves and/or closures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/87917—Flow path with serial valves and/or closures
    • Y10T137/87981—Common actuator

Definitions

  • the invention relates to an electro-hydraulic actuator for turbine valves according to the preamble of the claim.
  • the actuators of the individual turbine valves are always supplied with hydraulic energy via a central hydraulic supply system, which comprises a central hydraulic fluid reservoir and usually several fluid pumps working against hydraulic pressure accumulators. Accordingly, at least two pipes are required for connecting an actuator to the central hydraulic supply system, with one pipe taking care of supplying the actuator with pressurized hydraulic fluid, while the other pipeline feeds the hydraulic fluid that flows when the hydraulic components are relieved into the central hydraulic fluid reservoir leads back.
  • a central hydraulic supply system which comprises a central hydraulic fluid reservoir and usually several fluid pumps working against hydraulic pressure accumulators.
  • at least two pipes are required for connecting an actuator to the central hydraulic supply system, with one pipe taking care of supplying the actuator with pressurized hydraulic fluid, while the other pipeline feeds the hydraulic fluid that flows when the hydraulic components are relieved into the central hydraulic fluid reservoir leads back.
  • the valve housing of the quick-closing valve forms part of the control valve housing, which is arranged across the turbine.
  • the hydraulic drive part of the quick-closing valve is a servo motor that is opened with oil from a control oil system and closed with spring force.
  • the control valve device has, for example, three or four control valves which open in succession, as a result of which the throttling of the entire device is kept low.
  • the individual valves are each actuated by a rotary servo motor, which is influenced by an electro-hydraulic converter, via a rotary shaft with a cam and a roller lever.
  • EP-A-0 040 732 and EP-A-0 040 737 avoid the disadvantages described above, since the hydraulic supply lines previously required and the effort associated with these lines can be dispensed with by integrating the hydraulic supply systems in the actuator.
  • the object of the invention is to remedy the aforementioned disadvantages and to provide an electrohydraulic actuator for a quick-closing valve and a control valve which on the one hand meets the high requirements in terms of actuating force and actuating speed and on the other hand avoids the problems associated with the transmission of hydraulic energy.
  • the electrohydraulic actuator for a quick-closing valve and a control valve proposed according to the invention to achieve the stated object is characterized in that the drives of the valves are structurally identical, that the compact units consisting of the valves and their associated drive are directly combined with the hydraulic supply, and that the hydraulic supply contains a volumetrically regulating oil delivery unit with an auxiliary pump for controlling the quick-closing valve, a variable pump and associated variable cylinder for controlling the control valve, and an electro-hydraulic valve for controlling the hydraulic flows of the pumps.
  • Another advantage of the invention can be seen in the fact that a hydraulic supply operates one control and one quick-closing valve. Because the hydraulic supply is no longer conditioned in terms of space, it can be made more robust, simpler and cheaper.
  • the hydraulic supply includes a volumetrically controlled oil delivery unit, which supplies the quantity for the actuation of the control valve.
  • This oil delivery unit also includes an auxiliary pump, which supplies the hydraulic quantity to act on the quick-closing valve as well as for the electro-hydraulic valve and for the adjustment cylinder of the adjustment unit of the pump.
  • the energy consumption of the unit is minimal because the variable displacement pump only supplies the quantity and pressure required by the control valve.
  • Fig. 1 electrohydraulic actuator for turbine valves for control and quick-closing valve.
  • the electrohydraulic actuator for turbine valves essentially consists of a hydraulic supply 1, an oil delivery unit 2 and two identical drives 3, 4, which are responsible for controlling the quick-closing valve 29 and the control valve 30.
  • the auxiliary pump 15 and adjusting pump 16 integrated in the oil delivery unit 2 deliver oil from the hydraulic tank 6 via the lines 32 and. 33.
  • the auxiliary pump 15 supplies the electro-hydraulic valve 10 with oil, a filter 8 being installed as an intermediate.
  • the drive 4 is also supplied with oil via the throttle 9 and line 34, as a result of which the quick-closing valve 29 opens.
  • the oil flows through the throttle 22a into the piston chamber of the adjusting cylinder 21a.
  • the spring 35a is compressed; the oil still present in the spring chamber can flow out to the tank 6 via the outlet 24.
  • the auxiliary pump 15 is secured against excess pressure by the pressure relief valve 7 and its outlet 24.
  • the control valve 30 While the quick-closing valve 29 opens completely, the control valve 30 must have a regulating effect on the amount of steam flowing through the steam line 26 to the turbine.
  • the variable displacement pump 16 in turn supplies the drive 3 with oil via the line 37.
  • the dynamics of the opening of the control valve 30 do not differ from that of the quick-closing valve 29, i.e. the piston chamber of the adjusting cylinder 21 is acted upon by the throttle 22, whereupon the spring 35 is compressed and the residual oil remaining therein can flow back to the tank 6 via the outlet 24.
  • the degree of opening of the control valve 30 is signaled by an electrical setpoint 27 to the electro-hydraulic valve 10.
  • the adjustment quantity entered on the adjustment cylinder 18 causes a change in the delivery quantity of the adjustment pump 16, whereby oil is additionally applied to the piston chamber of the adjustment cylinder 21 and the adjustment valve 30 accordingly assumes a new opening position.
  • the desired degree of opening of the control valve 30 is maintained by continuously comparing the feedback signal 28 from the feedback sensor 5 with the setpoint 27 in the comparator 36. A resulting deviation between the setpoint and actual value is signaled to the electro-hydraulic valve 10. If the control valve 30 opens too large, the control cylinder 18 closes by means of spring force.
  • the variable displacement pump 16 now delivers less accordingly; the excess oil from the actuating cylinder 18 flows to the electro-hydraulic valve 10 and from there via the outlet 24 back to the tank.
  • variable displacement pump 16 Securing the variable displacement pump 16 against excess pressure is taken over by the pressure limiting valve 11 and its outlet 24.
  • the control valve 30 When the control valve 30 is completely open, the maximum pressure defined by the pressure relief valve 11 is set, the set pressure of the pressure relief valve 11 being at least the sum of the pressure force and the spring force of the adjustment cylinder 21.
  • the control valve spindle is therefore constantly loaded.
  • the directional control valve 13 In order to prevent this constant heavy load, the directional control valve 13 is switched and the pressure is reduced by the limit switch on the control valve 30, when the control valve 30 is in its fully open position, until it corresponds to the value defined in the pressure relief valve 14.
  • a filter 12 is installed in front of the directional control valve 13 in the outflow direction.
  • the outflow amplifier 19 switches on and opens. Via the bypass line 31, the oil under pressure in the piston chamber flows into the spring chamber of the adjusting cylinder 21 and from there via the outlet 24 back into the tank 6. This prevents the pump and lines from swallowing large amounts of oil during these load changes.
  • the throttles 23, 23a are provided so that the pumps 15, 16 can deliver a minimum amount of oil which is advantageous for their cooling during operation under constant load, which ensure this recirculation.
  • the two-way valves 20, 20a open, controlled by the electrical signals 38, 38a.
  • the drain amplifiers 19, 19a also open.
  • the oil can thus suddenly escape from the piston spaces via the bypass lines 31, 31a a into the spring spaces of the adjusting cylinders 21, 21a and flow out from here through the already opened two-way valves 20, 20a via 24.
  • Information aimed at closure is simultaneously brought in via the electrical setpoint 27.
  • the pump 16 is reduced to zero.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Control Of Turbines (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

Die Erfindung betrifft einen elektrohydraulischen Stellantrieb für Turbinenventile gemäss Oberbegriff des Patentanspruchs.The invention relates to an electro-hydraulic actuator for turbine valves according to the preamble of the claim.

Im Turbinenbau erfolgt die Versorgung der Stellantriebe der einzelnen Turbinenventile mit hydraulischer Energie stets über ein zentrales hydraulisches Versorgungssystem, welches einen zentralen Hydraulikflüssigkeitsbehälter und meistens mehrere gegen hydraulische Druckspeicher arbeitende Flüssigkeitspumpen umfasst. Für die Verbindung eines Stellantriebes mit dem zentralen hydraulischen Versorgungssystem sind demnach jeweils mindestens zwei Rohrleitungen erforderlich, wobei die eine Rohrleitung die Versorgung des Stellantriebes mit unter Druck stehender Hydraulikflüssigkeit übernimmt, während die andere Rohrleitung die bei einer Entlastung der hydraulischen Bauteile ablaufende Hydraulikflüssigkeit in den zentralen Hydraulikflüssigkeitsbehälter zurückführt. Um schmutzunempfindlichere Stellantriebe zu erhalten, arbeitet man vorteilhaft mit relativ tiefen Betriebsdrücken; dies hat allerdings zur Folge, dass grosse Öltanks vorgesehen werden müssen. Will man von einem zentralen hydraulischen Versorgungssystem alle Stellantriebe einer Turbine bedienen, so weist die Anlage zwangsläufig viele lange Ölleitungen auf. Um die Übertragungssicherheit der hydraulischen Energie zu gewährleisten, erfordern diese Rohrleitungen einen erheblichen Aufwand für Planung, Konstruktion, Qualitätssicherung und Wartung. Ausser Druckschwingungen und Druckspitzen in langen Leitungen ist insbesondere auch die Beanspruchung durch Wärmedehnung zu berücksichtigen. Schliesslich muss auch noch aus Sicherheitsgründen die von einem Bruch der Leitungen im Warmbereich ausgehende Brandgefahr berücksichtigt werden. Wohl liesse sich im Interesse des Brandschutzes die Brandgefahr durch den Einsatz doppelwandiger Rohre reduzieren, allein bringt dies hinsichtlich Verlegung und Zugänglichkeit erhebliche Probleme mit sich. Hinsichtlich Brandschutzes kann der Einsatz von schwer brennbaren Hydraulikflüssigkeiten erwogen werden. Derartige Hydraulikflüsssigkeiten sind jedoch kostspielig, erfordern auf Grund ihrer geringen Alterungsstabilität eine Regenerieranlage, die Instruktionen der Lieferanten müssen genauestens beachtet werden und sind gegenüber Wärmeeinwirkungen sehr zersetzungsgefährdet.In turbine construction, the actuators of the individual turbine valves are always supplied with hydraulic energy via a central hydraulic supply system, which comprises a central hydraulic fluid reservoir and usually several fluid pumps working against hydraulic pressure accumulators. Accordingly, at least two pipes are required for connecting an actuator to the central hydraulic supply system, with one pipe taking care of supplying the actuator with pressurized hydraulic fluid, while the other pipeline feeds the hydraulic fluid that flows when the hydraulic components are relieved into the central hydraulic fluid reservoir leads back. In order to obtain actuators that are less sensitive to dirt, it is advantageous to work with relatively low operating pressures; however, this means that large oil tanks have to be provided. If you want to operate all the actuators of a turbine from a central hydraulic supply system, the system inevitably has many long oil lines. In order to ensure the transmission security of the hydraulic energy, these pipelines require considerable effort for planning, construction, quality assurance and maintenance. In addition to pressure fluctuations and pressure peaks in long lines, the stress caused by thermal expansion must also be taken into account. Finally, for safety reasons, the risk of fire from a broken pipe in the warm area must also be taken into account. In the interest of fire protection, the risk of fire could be reduced by using double-walled pipes, but this alone causes considerable problems with regard to laying and accessibility. With regard to fire protection, the use of flame-resistant hydraulic fluids can be considered. However, such hydraulic fluids are expensive, require a regeneration system due to their low aging stability, the instructions of the suppliers must be followed carefully and are very susceptible to decomposition when exposed to heat.

Ein Beispiel für die Kombination eines Schnellschlussventils und einer Regelventileinrichtung, bei der die erwähnten vielen und langen Ölleitungen vorkommen, ist in den Brown-Boveri-Mitteilungen, Bd. 36, Heft 6/1976, S. 354-359 beschrieben. Dabei bildet das Ventilgehäuse des Schnellschlussventils einen Bestandteil des Regelventilgehäuses, das quer über der Turbine angeordnet ist. Der hydraulische Antriebsteil des Schnellschlussventils ist ein Servomotor, der mit Öl aus einem Regelölsystem geöffnet und mit Federkraft geschlossen wird. Die Regelventileinrichtung weist zum Beispiel drei oder vier Regelventile auf, die nacheinander öffnen, wodurch die Drosselung der ganzen Einrichtung gering gehalten wird. Die einzelnen Ventile werden jeweils von einem durch einen elektrohydraulischen Wandler beeinflussten Drehservomotor über eine Drehwelle mit einem Nocken sowie einem Rollenhebel betätigt.An example of the combination of a quick-closing valve and a control valve device, in which the many and long oil lines mentioned occur, is described in Brown-Boveri-Mitteilungen, Vol. 36, Issue 6/1976, pp. 354-359. The valve housing of the quick-closing valve forms part of the control valve housing, which is arranged across the turbine. The hydraulic drive part of the quick-closing valve is a servo motor that is opened with oil from a control oil system and closed with spring force. The control valve device has, for example, three or four control valves which open in succession, as a result of which the throttling of the entire device is kept low. The individual valves are each actuated by a rotary servo motor, which is influenced by an electro-hydraulic converter, via a rotary shaft with a cam and a roller lever.

Die in den EP-A-0 040 732 und EP-A-0 040 737 bekanntgegebenen Lösungen vermeiden die oben beschriebenen Nachteile, indem durch die Integration des hydraulischen Versorgungssysteme in den Stellantrieb die bisher erforderlichen Hydraulikzuleitungen und der mit diesen Leitungen verbundene Aufwand entfallen können.The solutions disclosed in EP-A-0 040 732 and EP-A-0 040 737 avoid the disadvantages described above, since the hydraulic supply lines previously required and the effort associated with these lines can be dispensed with by integrating the hydraulic supply systems in the actuator.

Diese Anordnung weist jedoch Nachteile auf:

  • a) Für jeden Stellantrieb muss ein eigenes hydraulisches Versorgungssystem zugeordnet werden. Bei der Vielzahl von Schnellschluss- und Stellventilen einer Turbine ist dementsprechend eine gleich grosse Zahl hydraulischer Versorgungssysteme vorzusehen; entsprechend gross ist auch der finanzielle Aufwand.
  • b) Da das jeweilige hydraulische Versorgungssystem eine autonome Einheit bildet, muss bei Ausfall der Flüssigkeitspumpe eine zweite zuschaltbare Flüssigkeitspumpe vorgesehen werden, welche von einem zweiten Elektromotor angetrieben ist. Durch diese Massnahme wird zwar die Betriebssicherheit des Stellantriebes erhöht, allerdings muss dabei eine entsprechende Vergrösserung des Bauvolumens und die Kosten des hydraulischen Versorgungssystems in Kauf genommen werden.
  • c) Aus denselben Überlegungen wie unter b) muss der hydraulische Druckspeicher in mindestens zwei Teilspeicher unterteilt werden, wobei das Speichervolumen der Teilspeicher derart bemessen ist, dass auch bei Ausfall eines Teilspeichers eine für die Betätigung des hydraulischen Stellzylinders ausreichende Hydraulikflüssigkeitsmenge verfügbar ist. Die daraus resultierende Konsequenz ist auch hier eine Vergrösserung des Bauvolumens und der Kosten des hydraulischen Versorgungssystems.
  • d) Aus obigen Überlegungen ist es deshalb fraglich, ob die angestrebte Minimierung des Bauvolumens des hydraulischen Versorgungssystems - soweit dieses mit dem Stellantrieb zu einem am Ventilgehäuse angeordneten kompakten Antriebsblock integriert werden kann - im vorgestellten Rahmen überhaupt machbar ist.
  • e) Darüber hinaus pflanzen sich die von den Ventilen bei Betrieb ausgehenden Vibrationen, insbesondere bei kurzfristig einander folgenden Lastwechseln, auf die relativ empfindlichen Elemente der Hydraulikversorgung fort. Die Lebensdauer dieser Elemente nimmt ab; Störungen des Betriebes sind die Folge.
However, this arrangement has disadvantages:
  • a) A separate hydraulic supply system must be assigned to each actuator. Given the large number of quick-closing and control valves in a turbine, an equal number of hydraulic supply systems must be provided accordingly; the financial outlay is correspondingly large.
  • b) Since the respective hydraulic supply system forms an autonomous unit, a second switchable liquid pump which is driven by a second electric motor must be provided if the liquid pump fails. Although this measure increases the operational safety of the actuator, a corresponding increase in the construction volume and the costs of the hydraulic supply system have to be accepted.
  • c) For the same considerations as under b), the hydraulic pressure accumulator must be divided into at least two partial accumulators, the accumulator volume of the partial accumulators being dimensioned such that even if one partial accumulator fails, a sufficient amount of hydraulic fluid is available for actuating the hydraulic actuating cylinder. The resulting consequence is an increase in the construction volume and the costs of the hydraulic supply system.
  • d) From the above considerations, it is therefore questionable whether the desired minimization of the construction volume of the hydraulic supply system - insofar as this can be integrated with the actuator to form a compact drive block arranged on the valve housing - is even feasible within the scope presented.
  • e) In addition, the vibrations emanating from the valves during operation, especially in the case of load changes which follow one another for a short time, propagate onto the relatively sensitive elements of the hydraulic supply. The lifespan of these elements decreases; Disruptions to operation are the result.

Aufgabe der Erfindung ist es, die vorgenannten Nachteile zu beheben und einen elektrohydraulischen Stellantrieb für ein Schnellschlussventil und ein Stellventil zu schaffen, der einerseits den hohen Anforderungen hinsichtlich Stellkraft und Stellgeschwindigkeit genügt und andererseits die mit der Übertragung hydraulischer Energie zusammenhängenden Probleme vermeidet.The object of the invention is to remedy the aforementioned disadvantages and to provide an electrohydraulic actuator for a quick-closing valve and a control valve which on the one hand meets the high requirements in terms of actuating force and actuating speed and on the other hand avoids the problems associated with the transmission of hydraulic energy.

Der zur Lösung der genannten Aufgabe erfindungsgemäss vorgeschlagene elektrohydraulische Stellantrieb für ein Schnellschlussventil und ein Stellventil ist dadurch gekennzeichnet, dass die Antriebe der Ventile baulich gleich ausgeführt sind, dass die aus den Ventilen und ihrem jeweils zugehörigen Antrieb bestehenden kompakten Einheiten unmittelbar mit der Hydraulikversorgung vereinigt sind, und dass die Hydraulikversorgung eine volumetrisch regelnde Ölfördereinheit mit einer Hilfspumpe zur Steuerung des Schnellschlussventils, eine Verstellpumpe und zugehörigen Verstellzylinder zur Steuerung des Stellventils sowie ein elektrohydraulisches Ventil zur Steuerung der Hydraulikströme der Pumpen enthält.The electrohydraulic actuator for a quick-closing valve and a control valve proposed according to the invention to achieve the stated object is characterized in that the drives of the valves are structurally identical, that the compact units consisting of the valves and their associated drive are directly combined with the hydraulic supply, and that the hydraulic supply contains a volumetrically regulating oil delivery unit with an auxiliary pump for controlling the quick-closing valve, a variable pump and associated variable cylinder for controlling the control valve, and an electro-hydraulic valve for controlling the hydraulic flows of the pumps.

Die Vorteile der Erfindung sind im wesentlichen darin zu sehen, dass durch die vorgeschlagene Lösung der Anbau je eines Stell- und Schnellschlussventils an jedem Turbineneinlassventil, vom benötigten und von dem zur Verfügung stehenden Platz her betrachtet, problemlos bewerkstelligt werden kann.The advantages of the invention are to be seen essentially in the fact that the proposed solution enables the installation of one control and one quick-closing valve on each turbine inlet valve, from the required space and from the available space, without any problems.

Dadurch, dass die beiden Antriebe gleicher Ausführung sind, ist der Grad der Austauschbarkeit grösstmöglich erreicht.The fact that the two drives are of the same design means that the degree of interchangeability has been achieved as far as possible.

Ein weiterer Vorteil der Erfindung ist darin zu sehen, dass eine Hydraulikversorgung je ein Stell-und Schnellschlussventil bedient. Dadurch, dass die Hydraulikversorgung platzmässig nicht mehr konditioniert ist, kann sie robuster, einfacher und billiger gebaut werden.Another advantage of the invention can be seen in the fact that a hydraulic supply operates one control and one quick-closing valve. Because the hydraulic supply is no longer conditioned in terms of space, it can be made more robust, simpler and cheaper.

Ein Vorteil der Erfindung ist des weiteren darin zu sehen, dass die Hydraulikversorgung eine volumetrisch geregelte Ölförderungseinheit beinhaltet, welche die Menge für die Beaufschlagung des Stellventils liefert. Zu dieser Ölförderungseinheit gehört auch eine Hilfspumpe, welche die Hydraulikmenge zur Beaufschlagung des Schnellschlussventils sowie für das elektrohydraulische Ventil und für den Verstellzylinder der Verstelleinheit der Pumpe liefert. Der Energieverbrauch der Einheit wird minimal, denn die Verstellpumpe liefert nur jene Menge und den Druck, die vom Stellventil benötigt werden.Another advantage of the invention can be seen in the fact that the hydraulic supply includes a volumetrically controlled oil delivery unit, which supplies the quantity for the actuation of the control valve. This oil delivery unit also includes an auxiliary pump, which supplies the hydraulic quantity to act on the quick-closing valve as well as for the electro-hydraulic valve and for the adjustment cylinder of the adjustment unit of the pump. The energy consumption of the unit is minimal because the variable displacement pump only supplies the quantity and pressure required by the control valve.

Anhand der Zeichnung sind Aufbau und Wirkungsweise eines Ausführungsbeispiels der Erfindung schematisch dargestellt und näher erläutert.Based on the drawing, the structure and mode of operation of an embodiment of the invention are shown schematically and explained in more detail.

Es zeigt:It shows:

Fig. 1 Elektrohydraulischer Stellantrieb für Turbinenventile für Stell- und Schnellschlussventil.Fig. 1 electrohydraulic actuator for turbine valves for control and quick-closing valve.

Wie aus Fig. 1 ersichtlich ist, besteht der elektrohydraulische Stellantrieb für Turbinenventile im wesentlichen aus einer Hydraulikversorgung 1, einer Ölförderungseinheit 2 und aus zwei gleichen Antrieben 3, 4, welche für die Steuerung des Schnellschlussventils 29 und Stellventils 30 verantwortlich sind. Mit dem Start des Motors 17 fördern die der Ölförderungseinheit 2 integrierten Hilfspumpe 15 und Verstellpume 16 Öl aus dem Hydrauliktank 6 über die Leitungen 32 resp. 33.As can be seen from FIG. 1, the electrohydraulic actuator for turbine valves essentially consists of a hydraulic supply 1, an oil delivery unit 2 and two identical drives 3, 4, which are responsible for controlling the quick-closing valve 29 and the control valve 30. With the start of the engine 17, the auxiliary pump 15 and adjusting pump 16 integrated in the oil delivery unit 2 deliver oil from the hydraulic tank 6 via the lines 32 and. 33.

Die Hilfspumpe 15 versorgt das elektrohydraulische Ventil 10 mit Öl, wobei intermediär ein Filter 8 eingebaut ist. Zugleich wird der Antrieb 4 über die Drossel 9 und Leitung 34 auch mit Öl versorgt, wodurch das Schnellschlussventil 29 öffnet. Hierzu fliesst das Öl durch die Drossel 22a in den Kolbenraum des Verstellzylinders 21a. Die Feder 35a wird zusammengedrückt; das in der Federkammer noch vorhandene Öl kann über den Ablauf 24 zum Tank 6 abfliessen. Die Sicherung der Hilfspumpe 15 gegen Überdruck wird vom Druckbegrenzungsventil 7 und dessen Ablauf 24 übernommen.The auxiliary pump 15 supplies the electro-hydraulic valve 10 with oil, a filter 8 being installed as an intermediate. At the same time, the drive 4 is also supplied with oil via the throttle 9 and line 34, as a result of which the quick-closing valve 29 opens. For this purpose, the oil flows through the throttle 22a into the piston chamber of the adjusting cylinder 21a. The spring 35a is compressed; the oil still present in the spring chamber can flow out to the tank 6 via the outlet 24. The auxiliary pump 15 is secured against excess pressure by the pressure relief valve 7 and its outlet 24.

Während das Schnellschlussventil 29 ganz öffnet, muss das Stellventil 30 auf die durch die Dampfleitung 26 zur Turbine strömende Dampfmenge regulierend einwirken können. Die Verstellpumpe 16 versorgt ihrerseits über die Leitung 37 den Antrieb 3 mit Öl. Die Dynamik des Öffnens des Stellventils 30 unterscheidet sich nicht von derjenigen des Schnellschlussventils 29, d.h. der Kolbenraum des Verstellzylinders 21 wird über die Drossel 22 beaufschlagt, worauf die Feder 35 zusammengedrückt wird und das darin verbliebene Restöl über den Ablauf 24 zum Tank 6 rückfliessen kann.While the quick-closing valve 29 opens completely, the control valve 30 must have a regulating effect on the amount of steam flowing through the steam line 26 to the turbine. The variable displacement pump 16 in turn supplies the drive 3 with oil via the line 37. The dynamics of the opening of the control valve 30 do not differ from that of the quick-closing valve 29, i.e. the piston chamber of the adjusting cylinder 21 is acted upon by the throttle 22, whereupon the spring 35 is compressed and the residual oil remaining therein can flow back to the tank 6 via the outlet 24.

Der Grad der Öffnung des Stellventils 30 wird von einem elektrischen Sollwert 27 dem elektrohydraulischen Ventil 10 signalisiert. Die auf den Verstellzylinder 18 eingegebene Verstellgrösse bewirkt eine Förderungsmengenänderung der Verstellpumpe 16, wodurch der Kolbenraum des Stellzylinders 21 zusätzlich mit Öl beaufschlagt wird und das Stellventil 30 infolgedessen entsprechend eine neue Öffnungsposition einnimmt. Der gewollte Öffnungsgrad des Stellventils 30 wird eingehalten, indem im Vergleichsglied 36 das aus dem Rückführgeber 5 stammende Rückführsignal 28 mit dem Sollwert 27 ständig verglichen wird. Eine hieraus resultierende Abweichung zwischen Soll- und Istwert wird dem elektrohydraulischen Ventil 10 signalisiert. Bei zu grosser Öffnung des Stellventils 30 schliesst der Stellzylinder 18 mittels Federkraft. Die Verstellpumpe 16 fördert nun entsprechend weniger; das aus dem Stellzylinder 18 überschüssige Öl fliesst zum elektrohydraulischen Ventil 10 und von hier über den Ablauf 24 zum Tank zurück.The degree of opening of the control valve 30 is signaled by an electrical setpoint 27 to the electro-hydraulic valve 10. The adjustment quantity entered on the adjustment cylinder 18 causes a change in the delivery quantity of the adjustment pump 16, whereby oil is additionally applied to the piston chamber of the adjustment cylinder 21 and the adjustment valve 30 accordingly assumes a new opening position. The desired degree of opening of the control valve 30 is maintained by continuously comparing the feedback signal 28 from the feedback sensor 5 with the setpoint 27 in the comparator 36. A resulting deviation between the setpoint and actual value is signaled to the electro-hydraulic valve 10. If the control valve 30 opens too large, the control cylinder 18 closes by means of spring force. The variable displacement pump 16 now delivers less accordingly; the excess oil from the actuating cylinder 18 flows to the electro-hydraulic valve 10 and from there via the outlet 24 back to the tank.

Die Sicherung der Verstellpumpe 16 gegen Überdruck wird vom Druckbegrenzungsventil 11 und dessen Ablauf 24 übernommen.Securing the variable displacement pump 16 against excess pressure is taken over by the pressure limiting valve 11 and its outlet 24.

Wenn das Stellventil 30 ganz offen ist, stellt sich der durch das Druckbegrenzungsventil 11 definierte maximale Druck ein, wobei der eingestellte Druck des Druckbegrenzungsventils 11 mindestens die Summe aus Druckkraft und Federkraft des Verstellzylinders 21 ist. Die Stellventilspindel ist somit dauernd belastet. Um diese dauernde starke Belastung zu verhüten, wird über nicht eingezeichnete Endschalter am Stellventil 30, bei dessen voll offener Lage, das Wegeventil 13 geschaltet und der Druck soweit abgesenkt, bis er mit dem im Druckbegrenzungsventii 14 definierten Wert übereinstimmt.When the control valve 30 is completely open, the maximum pressure defined by the pressure relief valve 11 is set, the set pressure of the pressure relief valve 11 being at least the sum of the pressure force and the spring force of the adjustment cylinder 21. The control valve spindle is therefore constantly loaded. In order to prevent this constant heavy load, the directional control valve 13 is switched and the pressure is reduced by the limit switch on the control valve 30, when the control valve 30 is in its fully open position, until it corresponds to the value defined in the pressure relief valve 14.

Das überschüssige Öl wird über den Ablauf 24 in den Tank 6 zurückgeführt. Vor dem Wegeventil 13 in Abströmungsrichtung ist noch ein Filter 12 eingebaut.The excess oil is returned to the tank 6 via the outlet 24. A filter 12 is installed in front of the directional control valve 13 in the outflow direction.

Bei schnellen Lastabsenkungen der Turbine schaltet der Abflussverstärker 19 ein und macht auf. Über die Bypassleitung 31 fliesst das im Kolbenraum unter Druck stehende Öl in den Federraum des Verstellzylinders 21 und von hier über den Ablauf 24 in den Tank 6 zurück. Dadurch vermeidet man, dass Pumpe und Leitungen bei diesen Laständerungen grosse Mengen Öl schlucken müssen.When the load on the turbine drops rapidly, the outflow amplifier 19 switches on and opens. Via the bypass line 31, the oil under pressure in the piston chamber flows into the spring chamber of the adjusting cylinder 21 and from there via the outlet 24 back into the tank 6. This prevents the pump and lines from swallowing large amounts of oil during these load changes.

Damit die Pumpen 15, 16 während des Betriebes bei konstanter Last eine zu ihrer Kühlung vorteilhafte minimale Ölmenge fördern können, sind die Drosseln 23, 23a vorgesehen, welche ebendiese Rezirkulation gewährleisten.The throttles 23, 23a are provided so that the pumps 15, 16 can deliver a minimum amount of oil which is advantageous for their cooling during operation under constant load, which ensure this recirculation.

Bei Schnellschluss machen die Zweiwegeventile 20, 20a, gesteuert durch die elektrischen Signale 38, 38a, auf. Ebenfalls machen die Abflussverstärker 19, 19a auf. Das Öl kann somit aus den Kolbenräumen über die Bypassleitungen 31, 31a a schlagartig in die Federräume der Verstellzylinder 21, 21a entweichen und von hier durch die bereits geöffneten Zweiwegeventile 20, 20a über 24 abfliessen. Eine auf Schliessung gerichtete Information wird gleichzeitig über den elektrischen Sollwert 27 herangetragen. Die Förderung der Pumpe 16 geht auf Null zurück.In the event of a quick close, the two-way valves 20, 20a open, controlled by the electrical signals 38, 38a. The drain amplifiers 19, 19a also open. The oil can thus suddenly escape from the piston spaces via the bypass lines 31, 31a a into the spring spaces of the adjusting cylinders 21, 21a and flow out from here through the already opened two-way valves 20, 20a via 24. Information aimed at closure is simultaneously brought in via the electrical setpoint 27. The pump 16 is reduced to zero.

Claims (1)

  1. Electro-hydraulic actuating drive for a quick closure type valve (29) and a control valve (30) for controlling a steam turbine, having a hydraulic supply system (1), the drives (4; 3) of the two valves (29; 30) being combined with the latter to form a compact unit, characterized in that the drives (4; 3) of the valves (29; 30) are of identical design, that the compact units consisting of the valves (29; 30) and their particular associated drive (4; 3) are directly combined with the hydraulic supply system (1), and that the hydrauly supply system (1) contains an oil pumping unit (2), having volumetric control, with an auxiliary pump (15) for controlling the quick closure type valve (29), a variable delivery pump (16) and associated variable displacement cylinder (18) for controlling the control valve (30) and an electro-hydraulic valve (10) for controlling the hydraulic flows of the pumps (15; 16).
EP84105238A 1983-05-30 1984-05-09 Electro-hydraulic actuator for turbine valves Expired EP0127027B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH2955/83 1983-05-30
CH295583 1983-05-30

Publications (2)

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EP0127027A1 EP0127027A1 (en) 1984-12-05
EP0127027B1 true EP0127027B1 (en) 1988-03-09

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EP84105238A Expired EP0127027B1 (en) 1983-05-30 1984-05-09 Electro-hydraulic actuator for turbine valves

Country Status (7)

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US (1) US4589444A (en)
EP (1) EP0127027B1 (en)
JP (1) JPS59231108A (en)
CS (1) CS244819B2 (en)
DE (1) DE3469777D1 (en)
PL (1) PL145034B1 (en)
YU (1) YU43361B (en)

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US10473128B2 (en) 2014-12-19 2019-11-12 Voith Patent Gmbh Actuating drive for a control valve, in particular steam turbine control valve and method for operating same

Also Published As

Publication number Publication date
EP0127027A1 (en) 1984-12-05
YU85884A (en) 1987-12-31
PL145034B1 (en) 1988-07-30
YU43361B (en) 1989-06-30
DE3469777D1 (en) 1988-04-14
US4589444A (en) 1986-05-20
PL247906A1 (en) 1985-03-12
JPS59231108A (en) 1984-12-25
CS394484A2 (en) 1985-08-15
JPH0472042B2 (en) 1992-11-17
CS244819B2 (en) 1986-08-14

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