摘要:
An auxiliary feedwater valve control apparatus (1) of a steam generator (103) that operates an auxiliary feedwater valve (123) in an auxiliary feed water system provided as a protective system of a main feed water system that feeds secondary cooling water to a steam generator (103), includes a water-level detection means (125) that detects a water level of secondary cooling water in the steam generator (103), a water-level-deviation calculation means (3) that calculates a deviation between a preset target water level and a water level detected by the water-level detection means (125), a valve-operation setting means (4) that sets an aperture of the auxiliary feedwater valve (123) corresponding to a deviation of the water level, and a valve drive means (5) that outputs a signal for driving the auxiliary feedwater valve (123) corresponding to setting by the valve-operation setting means (4).
摘要:
A circuit for controlling the fail-safe operation of a measurement and control apparatus (not shown) such as is used in a steam raising plant to monitor the water level in a steam generation vessel. It includes a sensor (10) which comprises an electrode which in use is inserted into a water/steam column (not shown) to detect the presence or absence of water. The apparatus detects the presence or absence of water by making a measurement of the impedance experienced in a gap between an insulated tip of the electrode and a surface held at a reference voltage or else connected to ground. The apparatus may be configured to provide an alarm. The circuit comprises comparators (IC1 and IC2), a phase detector (IC3) and a triple redundant drive circuit (12) which drives a relay (14) to indicate a normal or an abnormal/fault condition.
摘要:
An auxiliary feedwater valve control apparatus (1) of a steam generator (103) that operates an auxiliary feedwater valve (123) in an auxiliary feed water system provided as a protective system of a main feed water system that feeds secondary cooling water to a steam generator (103), includes a water-level detection means (125) that detects a water level of secondary cooling water in the steam generator (103), a water-level-deviation calculation means (3) that calculates a deviation between a preset target water level and a water level detected by the water-level detection means (125), a valve-operation setting means (4) that sets an aperture of the auxiliary feedwater valve (123) corresponding to a deviation of the water level, and a valve drive means (5) that outputs a signal for driving the auxiliary feedwater valve (123) corresponding to setting by the valve-operation setting means (4).
摘要:
Für den automatisierten Betrieb von Dampfkesseln und ähnlichen wärmetechnischen Anlagen sind Steuergeräte (1) mit zwei Sicherheitsrelais (9, 10) für die Sicherheitsstromleitung (7) einzusetzen. Das erfindungsgemäße Steuergerät (1) weist zwei zu den Sicherheitsrelais (9, 10) parallele Nebenschlussleitungen (11, 13, 14; 12, 13, 14) auf. Die Sicherheitsrelais (9, 10) weisen Ruhekontakte (17) auf. Zur Prüfung der Schaltfähigkeit werden die Sicherheitsrelais (9, 10) in ihre Ruhestellung umgeschaltet und die Spannungsänderung an ihren Ruhekontakten (17) überwacht. Bei fehlender Spannung ergeht ein Fehlersignal. Während der Prüfung wird die parallele Nebenschlussleitung (11, 13, 14; 12, 13, 14) geschlossen. Die Sicherheitsstromleitung (7) ist daher während der Prüfung nicht unterbrochen. Zur Steuerung der Sicherheitsrelais (9, 10) sind Schaltverstärker (27, 28) mit einer Ansprech- und Aktionszeit vorgesehen, die einen Bruchteil der vorgegebenen Ansprechzeit der Sicherheitsrelais (9, 10) beträgt. Zur Prüfung der elektrischen Ansteuerung werden die Antriebe (21) der Sicherheitsrelais (9, 10) stromlos geschaltet und die Spannungsänderung an den Antrieben (21) überwacht. Bei unzureichender Spannungsänderung ergeht ein Fehlersignal. Die Sicherheitsrelais (9, 10) verharren während dieser Prüfung in ihrer Arbeitsstellung.
摘要:
A low liquid level sensor (12) in a hot water heating system permitting testing operability thereof in situ without draining down the system. The sensor (12) is located in a cavity (13) that has an opening (16) in the bottom thereof in fluid communication with the liquid in the vessel during normal operation of the system. The end of the opening is at a lower elevation than the sensor and liquid from the vessel (10) is in the cavity (13) during normal operation of the system. When the liquid drops to a predetermined low level the sensor activates the safety cut-off. Valved passage means are provided exteriorly of the vessel so that a gas can be injected into the cavity to pressurize the same and drive the liquid in the cavity through the opening into the vessel simulating a low water level condition. At the simulated low water level condition operability of the sensor can be determined. Means (26, 27) are provided to release the gas from the cavity. The sensor is mounted by an insulator (20) that projects into the cavity and the gas release means is spaced from the end of the cavity so that an air pocket is maintained reducing the tendency of conductive deposits to build up on the insulator. A fail-safe circuit is provided avoiding malfunctioning of the cut-off safety control should there be a large build up of conductive deposits on the insulator.
摘要:
La présente invention a pour objet un dispositif (1) de détection du niveau d'un liquide (4) dans une cuve (3), reliée à la terre (7), ledit dispositif comprenant un capteur (2) positionné à un niveau prédéterminé dans la cuve (3), un détecteur de courant (20) relié au point de connexion (8) du capteur (2), pour détecter un courant lorsque le liquide (4) atteint le niveau prédéterminé, un circuit (10) d'alimentation pour alimenter le capteur (2), comprenant un premier point relié à la phase (5) (ou au neutre (6)) du réseau et un deuxième point relié au neutre (6) (ou à la phase (5)); le circuit (10) comprenant un montage pour relier le point de connexion (8) à un potentiel différent de la terre (7) lorsque le premier point est relié à la phase (5) et le deuxième point est relié au neutre (6), ou inversement.