Alarm devices

There are three basic requirements that Hquid level control devices are designed to satisfy alarm functions, pump/valve control, and transmitted output signal to track level continuously. Alarm devices provide warning or shutdown functions when process levels pass a predeterrnined point in the vessel pump /valve control devices turn on/off pumps or open/close valves at predeterrnined levels in the vessel and transmitters provide a proportional output signal over a predetermined span to send to a local meter or signal back to a control room. 

In a discussion of the various level technologies, it is important to know the differences between the various level requirements. The implementation of a particular technology, such as ultrasonic, is different for a single alarm device than it is for a transmitter. 

Continuous monitors usuaUy indicate the pollutant concentration on both an indicator and a chart recording. This provides a visual indication of the instantaneous emissions, along with a permanent record of the quantitative emissions over a period of time. The monitoring system may also be equipped with an alarm device to signal the operator if the allowable emission level is being exceeded. Data-logging systems coupled with micropro-... 

Figure 17-16 depicts typical devices containing arcing contacts enclosed in explosion-proof enclosures. Figure 17-17 shows typical explosion-proof alarm devices. A telephone instrument suitable for Class I, Divisions 1 and 2, Group D classified areas is shown by Figure 17-18. 

Figure 17-17. Standard explosion-proof alarm devices. Courtesy of Crouse-Hinds Electrical Construction Materials, a division of Cooper Industries, Inc.)...

Process Variable or Actuation Controlling Devices Measuring Alarm Devices Devices Primary Elements Wells Glass Devices for Visual Observation... 

Simple switches that can be manually activated can be considered a fire alarm device. Models are used which normally require the use of positive force, i.e., to avoid accident and fraudulent trips. Fire alarm switches normally can only be reset by special tools in order to trace the source of the alarm, however sophisticated data reporting systems with addressable data collection may make this requirement obsolete. 

Alarms should be able to be noticed at all areas of the facility, whether manned or considered technically unmanned. The basic theory for determining the number and location of audible alarm devices is that strategically placed and distributed devices will provide an efficient distributed level of sound, than one large centrally located device. 

Cooling and Lubrication Failures. All hydrogen gas compressor units shall be equipped with shutdown or alarm devices to activate in the event of inadequate cooling or lubrication of the units. 

Installation of alarm devices which indicate primary (controlling) regulator failure are useful and should be considered for monitor regulator systems. 

Miscellaneous household appliances Safety, alarm devices Waste compactors Mechanical performance Aesthetics Durability... 

Many units have instrumentation that will trip the unit in case of excessive feedwater contamination. Trip-limit recommendations are based on [he measurement of cation conductivity at the boiler inlet. An actual unit trip is usually preceded by alarms at the hotwell discharge to warn the operator of feedwater contamination and possible load reduction. In setting feedwater trip limits, protection of both the boiler and the turbine must be considered. A common arrangement consists of two cation conductivity alarm devices, both required to read high to initiate the trip sequence. A conductivity of 2 micromhos for five minutes or 5 micromhos for two minutes, results in a unit trip. Properly installed and maintained, these trip devices are highly reliable. 

Note In clinical trials, some people never respond to alarms at night regardless of the volume. An alarming device (receiver or pump) that is under covers, a pillow, or underneath a body is almost impossible to hear. If you are considering a continuous glucose sensor, be sure to investigate the device s alarms to see if they will meet your needs... 

Because of its higit toxicity, HCN must be used under strictlyindividual protection equipment and alarm devices. Very convenient pocket-detectors are now commercially available as well as more sophisticated permanent equipment. 

Easter SF, Martin JL, Fleming JB.The effect of a medication alarm device on patient compliance with topical pilocarpine. J Am OptomAssoc 1996 67 654-658. 

Attach one wire from an electric initiator blast ing cap, squib, or alarm device) to the screw or wire on... 

A lock-out relay is included in the circuit that allows indicating alarm lamps to light, the audible alarm to sound, and prevents restarting without resetting the system when shutdown occurs in an alarm situation. It also prevents alarm devices from functioning during normal shutdown. 

You will be able to defend your home and loved ones with the most outrageous infernal gagetry imaginabla Your territory will be a nightmare of boobytraps, mines and alarm devices. 

A.3.4.3 Continuous controls They allow to assure that the essential characteristics of the environment are maintained during production. The controls to be carried out routinely must be defined in relation to the conditions of work in each unit, for example measurement with, possibly, alarm devices, of relative pressure, temperature and relative humidity. 

Controlling devices Measuring devices Alarm devices ... 

Provide safety and alarm devices, such as fire-alarm systems, combustible-vapor detectors, flame arresters, pressure-relief venting of equipment, flame-failure controls for oil- and gas-fired equipment. 

The first two methods require rigid process control except in natural or slightly enriched reprocessing plants before plutonium partitioning. Other features of the layout include a calculated pitch on the process cell floors so that a major spill will not cause the solution depth to exceed criticality. A steam jet and sump pump with alarm devices are located in a geometrically safe sump at the low point in the cell area. To avoid loss of fissionable-fuel material, there should be no gravity connections between the process tanks and the waste storage area. 

C.l APPLICATION OF PROTECTIVE RELAYS, CONTROL AND ALARM DEVICES FOR POWER SYSTEM CIRCUITS... 

C.l Application of Protective Relays, Control and Alarm Devices for Power System Cirenits... 

In general practice, gas detection instruments working with electrochemical sensors are very commonly employed. These rather compact devices can be worn on the body, and therefore they are very suitable for monitoring personal exposure. The user is alerted in the case of hazardous concentrations in the working environment by an audible and visible alarm device. Usually, the instruments include a data logger, which enables the recorded data to be evaluated at a PC at a later point of time. The necessary software is normally supphed with the device. 

Berlin, Maryland, is another overlooked site. For example, a 1923 contingency plan provided for an estimated strength of 3053 personnel, 3355 gas masks, 500 horse masks, 150 protective suits, 1400 pounds of chloride of lime, 1100 extra canisters, 70 alarm devices, and 80 two-ounce cans of glycerine to be placed at the Berhn Station. This was never implemented but, obviously, this was a significant facility in the eyes of the Chemical Warfare Service (CWS). 

Alarm devices that are used in the course of normal operations... 

Brisbon, I. L., 1968, Evidence for the use of post-anal musk as an alarm device in the king snake Lampropeltis gelulus, Herpelologica 24 169-170. 

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