FIRE DETECTION AND ALARM SYSTEMS

当今防火目标的重点是在火势肆虐前早期察觉, 合理施救. 早期察觉有助于在 火势发展到严重危及生命和财产安全前控制住火情.
The key to achieving today’s fire protection goal is early detection and possible extinction of a fire before it becomes too deep seated. Early detection helps to control the fire before it becomes a serious threat to life and property.

火警探测和报警系统应在任何时候都处于可用状态, 电源常开,持续监控电路 异常和故障. 在控制和指示面板内将每个探测器和和手动报警点汇聚成群,可 在其内启动任一报警单元并产生声光报警信号.
The system is to be operable at times, with the power supplies and electric circuits continuously monitored for failure or fault. Detectors and manually operated call-points are grouped in sections and activation of any unit initiates an audible and visual alarm at the control panel and indicating units.

火警探测面板 Fire Detection Panel 
本船的火警探测面板装置安装在驾驶台,复示面板安装在消防控制站
The fire alarm detection panel on this ship is installed on the Bridge with repeater panels located at the Fire Control Station.

本系统包括一中心监控面板, 复示面板, 热力,烟雾, 火焰三合一探测感应器组 合, 手动报警点及报警器.
The system consists of a central control and monitoring panel, with repeater panels, a combination of heat, smoke and flame detectors, manual alarm activation points and alarm sounders.

船员可依此可迅速发现起火位置. 在火警探测面板上,裱有位置显示表,每一报 警位置装设有发光指示灯. 凭借此装置船员可迅速采取灭火步骤,避免无谓耽 搁.
Here the crew can quickly find out where a fire has started. A table is connected  to  the fire  alarm  panel showing,  with  light  indication,  which sections are in alarm. Through this arrangement the crew can take steps to extinguish the fire with no unnecessary loss of time.

下叙为 火警探测和报警系 统覆盖的区域表 :
Following is a list of Zones covered by the Fire Detection System:

区域 1: 住舱主甲板.
Zone 1: Accommodation Main Deck.

区域 2: 住舱艇甲板.
Zone 2: Accommodation Boat Deck.

等等 etc

感应探头  Detection Sensors
根据使用区域和用法有各种不同的感应探头. 根据作业区域的不同, 火警探测 器的使用原则根据以下四种主要的火灾特性的其中一个而定:
There are various types of sensing detectors, depending on the area and type of usage. Depending on the area of operation, the principle used in fire detectors depends on one of the four main characteristics of fire namely:

烟雾 (气溶胶): 燃烧总会产生气溶胶 (小微粒). 这种探头内装有一电离 室探测此类悬浮质小微粒., 即使对完全燃烧产生的不可见悬浮质, 当该 悬浮质分布密度足够时也能引起感应.
Smoke (Aerosols): A fire always produces Aerosols (tiny particles). In this type of detector, an ionization chamber is employed which detects such particles. It responds even to the invisible particles produced in a clear burning fire provided that the density of such particles is high enough.

烟雾 (可见): 可见的烟雾代表着火灾. 一些探头的工作原理是探测烟雾 粒子中零星的发光体探测火情.使用光敏装置能较早地探测到火灾情报.
Smoke (visible): Visible smoke is an indication of fire. Some of the detectors use the principle of light scatter on smoke particles to detect fire. Using a photo sensitive device to detect smoke it is possible to give an early warning.

热力: 因火灾产生的热力导致温度的升高现象可用来探测火情. 一些旧 式探头用蜡隔离触点, 温度升高引起蜡溶化, 触点相接而后产生报警. 此 类 探头的缺陷是一旦探头触发后就只能更换探头. 另一类使用双金属接 触产生电路的开闭. 使用时一外露一遮蔽,两者产生温差从而产生报警信 号. 另也有气动式装置可以使用.
Heat: Rise in temperature due to heat produced in a fire can be used to detect fire. Some old type of sensors used wax to separate the contacts. The wax melts due to the temperature rise, and the contact is made giving an alarm. The disadvantage of this type of sensor is that once the sensor is activated, this had to be replaced. Another type uses a bi- metal contact assembled to make or break an electrical circuit. By using such devices, one shielded and one exposed, a rate of rise effect is created which in turn activates the alarm. Pneumatic devices can also be used.

辐射: 此类探头的原理是探测火源发出的红外线,/紫外线. 这类探头可用 于火灾初始就产生明焰的场所.
Radiation: The principle used in these types of detectors is detecting the infra-red / ultra-violet radiation emitted by the fire source. These detectors can be used in places where certain fires produces flames right from the start.

以上描述了船上使用的不同探测系统的工作原理.
The above points describes the different principles used in fire detection system used on board ship.

船上存在极高的火灾风险,以及某些位置由于长期无人光顾因此需要装备探测 系统就显得尤为重要.通过选取合适的感应器或空气取样装置进行慎密布局则 可以实现这个目标.
On ships the risk of fire itself is very high and there are long periods of time when no one attends certain spaces. It is imperative to have a detection system. This is achieved by means of judicious placement of appropriate sensors or air sampling units.

烟雾探测器  SMOKE DETECTORS

电离式感烟探测器
Ionization smoke detectors: 
工作原理:
Principles of Operation:

•   此为点阵型火灾探测器.在感应室内带有少量放射性物质的点状探测器.
These are spot type of detectors having a small amount of radioactive material inside the sensing chamber.

•   此放射元素在感应室内将空气电离, 从而使两充电电极间空气产生导电 性, 存在一电流.
This radioactive element ionizes the air in the sensing chamber, thus rendering it conductive and permitting a current flow through the air between the charged electrodes.

•   当烟雾粒子电离空间时, 因空气混入杂质, 导致导电性降低.
When smoke particles enter the ionization area, they decrease the conductance of the air by attaining themselves to the ions, causing a reduction in mobility.

•   当导电性降低至一设定值时,  探测器工作报警.
When the conductance is less than a predetermined level, the detector responds indicating that there is a fire in a particular compartment.

光电式 烟雾 探测 器 , 遮光 原理
Photoelectric smoke detectors, Obscuring light principle:
工作原理:
Principles of Operation:

此探测器原理为一光源, 一光柱校准系统和一光敏原件组成.
The detector using this principle consists of a light source, a light beam collimating system and a photosensitive device.

当烟雾粒子进入光柱后, 降低了抵达光敏原件的光线强度, 从而产生 报警.
When smoke particles enter the light beam the light reaching the photosensitive device is reduced initiating the alarm.

此类探测装置为光柱型, 用于较大范围的开放区域.
These type of detectors are beam type detectors which are used to protect large open areas.

此类探测装置一头装光源, 另一头装接收器. 当烟雾粒子破坏光柱后 产生报警.
These detectors are installed with light source at one end and receiver at the other. When this beam of light is broken by smoke particles an alarm is raised.

光电式 烟雾 探测 器 , 散光 原理
Photoelectric smoke detectors, Light scattering principle: 
工作原理:
Principles of Operation:

此类探测器一般为点状探测器. 使用光线散射原理.
This type of detector is usually a spot type detector. The detector makes use of the principle of light scattering.

此类探测器包括一光源,一光敏原件. 设计在正常状态下灯柱不会射 向光敏原件.
The detector contains a light source and a photosensitive device so arranged that the light rays do not normally fall on the photosensitive device.

当烟雾粒子进入光柱后, 烟雾粒子将光柱散射到光敏原件, 从而产生 报警.
When smoke particles enter the light path, light strikes the particles and is scattered onto the photosensitive device, causing the detector to respond.

热力型探测器
HEAT DETECTORS
  
固 定 式 温 度 探 测器 , 双金属型
Fixed temperature detectors, Bimetal type: 

工作原理:
Principles of Operation:

此类探测器使用两种不同膨胀系数的金属工作.
This type of detector uses two metals with different coefficient of expansion.

当这两种不同膨胀系数的金属固定在一起并加热时, 高膨胀率的金属弯 向低膨胀率的金属一侧.
When both these metals are bonded together and heated, the metal with the higher expansion rate bends or flexes towards the metal having the lower expansion rate.

当这两种不同膨胀系数的金属固定在一起并加热时, 高膨胀率的金属弯 向低膨胀率的金属一侧.
This action closes the normally open circuit giving out an alarm.

固定式 温度 探测 器 , 可溶 性连 接型
Fixed temperature detectors, Fusible Link Type 

工作原理:
Principles of Operation:

此类探测器根据一些金属合金在相对较低的温度时溶化的原理工作. 一 般的溶化温度为 55oC 至 180oC.
This type of detector uses the fact that certain metal-alloys melt at relatively low temperature. The general range available is from 55oC to 180oC.

此类探测器由一个固定接触片和一对由可溶性连接金属合金抵住的接 触弹簧组成. 正常时电路开启, 不发出报警.
In this type the detector consists of a fixed contact blade and a pair of spring contact held under tension by a fusible alloy link. In this condition the electrical circuit is open and the alarm will not sound.

当周边空气温度升至可溶性连接金属合金的溶化点时, 接触弹簧分开, 并与固定接触片接触, 电路闭合, 发出报警. 此类探测器的报警工作范围 为 57oC 至 102oC.
When the temperature of the surrounding air reaches the melting point of the fusible link, the spring contacts separate and makes contact with the fixed contact blade, completing the electrical circuit and alarm is sounded. The range of operating temperature for this detector is 57oC to 102oC.

可溶性连接型探测器是不可以自我恢复的. 即是可溶性连接型探测器使 用完后可溶性连接金属合金需更换. 尽管大多数时期这仅是个简单的操 作. 切记在探测器使用完后更换可溶性连接金属合金前, 该探测器是无 效的.
Fusible detectors are not self-righting i.e. once the detector has been operated the link or fusible alloy needs replacing although in most cases this is a reasonably straight forward operation. Remember that the detector is ineffective until replacement takes place after operation.

温度上 升率 型探 测器 (使 用双 金属 型)
Rate of rise type (using bi-metal type) 
工作原理:
Principles of Operation:

此类探测器使用两种类似成份的双金属条, 但一根被遮蔽和保护以降低 其膨胀率.
In this type of detector two similar composition bi-metal strips are used but one is shielded and protected to reduce its rate of expansion.

当周边温度急剧上升时, 外露的金属条较遮蔽的金属条膨胀得更快, 引 起电路闭合, 发出报警.
If there is a rapid rise in temperature, the strip which is not shielded will expand faster than the strip which is shielded and will make close the electrical circuit thereby triggering the alarm.

在某些场所, 因其特性可能会发生非因火情而而致的温度轻微上升, 这 种情况因其温度上升较慢, 外露的金属条较遮蔽的金属条膨胀率相差无 几而保持同等距离, 不会发出报警.
In some places, due the nature of that area, there may be slight increase in temperature not necessarily due to fire. In such places, due to slow rate of increase in temperature, both the bimetallic strip will maintain the same distance apart and hence there will not be an alarm. 

上述特性会产生因缓慢燃烧, 温度上升较慢而不能报警的缺陷. 故此类 探测器应与另一固定温度探测器结合使用.
The property in the above point may be disadvantageous due to slow burning fires and hence a fixed temperature device is also fitted in this rate of rise type detector.

温度上 升率 型探 测器 (气 体膨 胀型 )
Rate of rise (Expansion of Gases) type: 
工作原理:
Principles of Operation:

此类探测器又称气动探测器, 因其在气室使用的气体一般为空气.
This type of detector is also known as the pneumatic detector as the gas used inside the chamber is usually air.

此类探测器包括一充满空气的气室和一柔性的隔膜. 当气室内空气受热 膨胀时, 柔性的隔膜受压上鼓, 引起电路闭合, 发出报警.
The detector consists of a chamber filled with air and a flexible diaphragm. When subject to heat the air in the chamber expands and applies pressure to the flexible diaphragm. This gradually pushes the diaphragm up until it meets the electrical contact, thereby completing the circuit and the alarm is raised.

在气室的一边有一细小补偿通风孔起温度上升率作用. 此补偿通风孔允 许部分空气逸出, 该孔调校到只可补偿正常情况下周边温度的升高.
A small compensating vent in the side of chamber is provided as a rate- of-rise element. The compensating vent will allow a certain amount of expanding air to escape, it will be carefully calibrated so as to compensate only for expansion caused by the normal and legitimate increases in the ambient temperature.

当周边温度快速上升时, 气室内空气受热快速膨胀的幅度大于从补偿通 风孔逸出空气的幅度, 柔性的隔膜受压上鼓, 引起由调整螺丝调节的电 路闭合, 发出报警.
When there is a rapid rise in temperature the air in the chamber expands much more rapidly than the compensating vent can release it and as a result the expanding air pushes the diaphragm against the electrical contact on the base of the rate of rise adjustment screw. This completes the electrical circuit and the alarm is raised.

上述特性会产生因缓慢燃烧, 温度上升较慢而不能报警的缺陷. 故此类探测器 应与另一固定温度探测器结合使用.
As mentioned earlier even in this type of detector, a fixed temperature element is provided – in case of a slow burning fire and the rate of rise element is unable to detect the slow rise in temperature.

火焰探测器
FLAME DETECTORS
工作原理:
Principles of Operation:

除烟雾和热力探测器用于探测火情外, 某些场所还使用火焰探测器探测火情.
Apart from smoke and heat being used to detect fires, in some places flames can also be used to detect fires.

火焰由三部分组成, 即为可见火焰, 红外线和紫外线. 因红外线和紫外线有 其特定的频率 (25 Hz), 探测器的滤波单元仅允许红外线和紫外线通过聚集 于光电管.
Flame consists of three parts i.e. visible flame, ultra violet rays and infra red rays. Since Infra red light and ultra violet rays have a particular frequency (25 Hz), the filter unit of the detector will only allow infrared or ultraviolet rays to pass through and focus on the photo electric cell.

光电管产生的信号经放大装置和延时装置后输送到报警单元. 延时装置降 低了一些高温物体和明火如火柴擦火, 锅炉点火器发火及喷灯发火而引起 的误报警.
This signal from the cell goes to the amplifier unit and time delay unit before passing to the alarm circuit. The time delay unit minimizes the incidence of false alarms due to heating elements and other naked flames like from match sticks flame or lighting to torches for firing boilers, or flames from blow lamp.

优点: Advantages:
-不须达到如热力, 烟雾探测器发生报警所需的燃烧产生物.
The combustion products need not reach the detector like heat and smoke detector for the alarm to be activated.

-此类探测器尤其适合开阔场所.
This detector is very useful in open space.

-能迅速探测到火警. Very quick in detection.

缺点:
Disadvantages:

-因烟雾会遮蔽火焰, 故烟雾的存在会降低此类探测器的工作效率.
The presence of smoke can reduce the effectiveness of the detector as smoke gives mask over the flame.

-此类探测器在报警前必须探测到可见火焰, 不能对热力, 烟雾产生报 警.
The detector must see the flame or fire before it will raise an alarm. It will not be able to sound an alarm by sensing heat or smoke.

船舶探测 器的位置（统计）
Location of Detectors on board.


All fire sensors to be marked on floor plates / deck immediately below with number, which is reflected in the PMS.
根据 “保养计划系统”的要求, 所有火警探头都应在其底部的地板, 甲板上清晰 标示.

手动火警报警点 
Manual Activation Points

除火警探测器外, 火警还可在船舶不同位置的手动火警报警点处触发报警. 报 警方式为打破保护玻璃罩, 按下报警按钮.
In addition to detectors, fire alarm can be activated from various Manual Activation Points situated in various parts of the ship. These can be activated by breaking the protective glass and pressing the alarm button.

手动火警报警按钮会产生一连续或周期性中断的火警钟声, 此报警还应与气 笛的通用报警结合.
Manual activating buttons may give a continuous or interrupted continuous ringing on the alarm bell. Such an alarm signal must be accompanied by the general emergency alarm signal sounded on the whistle.

船舶手动火警报警点的位置 （统计） 
Location of Manual Activation Points on board.


来源：王老轨