单选题The flame safeguard control system of a large automatic auxiliary boiler will provide fuel shut off in the case of high （）.A waterB voltageC fuel pressureD steam pressure

第一组

An automatic system usually consists of a control system and an information system. A control system is a system which measures the condition of some entity and, with the information, governs the state of a variable; i.e., speed, temperature, pressure, position, etc. The open-loop system is the simplest form. a control system may assume. It is distinguished from the closed-loop system by the lack of an input which measures the state of the controlled variable; such an input is called a feedback. In modern ships the open-loop system has practically disappeared and the closed-loop system which operates with a feed-back is extensively used. An information system serves the parallel function of monitoring system or plant performance. The monitoring function may serve a number of purposes; specifically it may indicate values of controlled variables to guide remote control operations, warn of off-limit conditions and provide record of performance. In many cases a visual and audible alarm may be provided to warn of off-limit conditions on board ship and, associated with this, the important variables will be recorded on demand. The automatic control system can be more sophisticated by incorporating digital-processing equipment, that is, a computer. This computer is usually fed with signals from all sensors. It scans the values of the sensors and generates alarm signals for off-limit conditions, acting as a super-supervisor. Sometimes, it can even make necessary and take the necessary action to optimize performance without human intervention.

The closed-loop system differs from the open-loop system by

A.the lack of a feedback

B.the presence of a feed back

C.the lack of a computer

D.the presence of a computer

A large metallic device，mounted directly in the piping (usually located at the dock near the point where the vapor hose is attached)，designed to prevent the passage of a rapidly moving flame through the piping is called a ______.

A.flame arrestor

B.flame screen

C.detonation arrestor

D.detonation blocker

A.ACC： AFC control ( clearing) center 票务清分中心

B.ACS ： Access control system 门禁系统

C.AGM： Automatic gate machine 自动检票机/闸机

D.APM：Automated people mover 旅客自动输送系统

Flame screens are used to ______.

A.contain flammable fumes

B.protect firefightiers from flames

C.prevent flames from entering tanks

D.keep flame and sparks from getting out of an engine’s exhaust system

The fuel oil supply system to an automatic auxiliary boiler, will automatically shutdown if the boiler ______.

A.steam demand is high

B.salinity is high

C.safety valve simmers(爆发)

D.burner flame is extinguished

Vessels required to be equipped with an approved backfire flame arrester are ______．

A.Those with diesel engines

B.All those with gasoline engines

C.Those with large engines only

D.None of the above

Which of the following requirements is NOT mentioned in successfully dealing with large volume and variety of transactions?

A．A large number of skillful staff and expertise.

B．Effective internal control system.

C．Complex accounting system.

D．Widespread use of electronic data processing.