Table 9-1.--Alarm, Safety, and Warning Systems

Table 9-1.--Alarm, Safety, and Warning Systems--Continued

System

Importance

Readiness Class

Circuit

Navigation horn operating system

Air lock warning

Air filter and flame arrester pressure differen-

tial alarm, or gasoline compartment exhaust

blower alarm

Oxygen-nitrogen plant ventilation exhaust alarm

Turret emergency alarm

Safety observer warning

Rocket and torpedo warning

4SN

Scavenging air blower high-temperature alarm

Shaft position alarm

Liquid level alarm

1TD

Boiler water level alarm

Deaerating feed tank water level alarm

2TD

Reactor compartment bilge tank alarm

5TD

6TD

Primary shield tank, expansion tank level alarm

Reactor plant fresh water cooling expansion tankd

7TD

level alarm

8TD

Reactor secondary shield tank level alarm

Lubricating oil sump tank liquid level alarm

9TD

11TD

Induction air sump alarm

12TD

Diesel oil sea water compensating system tank

liquid level alarm

14TD

Auxiliary fresh water tank low-level alarm

16TD

Pure water storage tank low-level alarm

17TD

Reserve feed tank alarm

18TD

Effluent tanks and contaminated laundry tank

high level alarm

presence of fires or overheated conditions in impor-

Relay Switches

tant compartments or spaces,

Relay switches are used in critical circuits to

A mercury thermostat (fig. 9-1) consists of a

sense power failure. Power failure causes the relay

column of mercury in a glass tube. Three electrical

contacts to close and initiate an alarm.

contacts are sealed into the glass tube. A resistor is

Mercury Thermostats

connected in parallel with the top and middle

contacts. The theme contacts along with the resistor

Mercury thermostats are used with the high-

and the mercury form a path for current flow. A

temperature alarm system (circuit F) to detect the

9-4