Trip devices

Pressure-measuring device This is provided for the operation of alarm or trip devices in the event the pressure within the casing falls below the permitted minimum. 

Consider a test program for periodically checking crint.iJ instruri. cfif, . md trip devices... 

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. 

First, safety critical systems must be reliable. These systems control releases in the event of accidents. It s necessary to have a critical analyzer, instrument and electrical system test program. This should consist of preventive maintenance and alarm and trip device testing for panel alarms, emergency isolation valves and other critical components. [7]... 

Connect firing leads to battery and switch. Mine can be remotely MATERIAL REQUIRED fired when needed or attached to trip device placed in path of ad ... 

Check low-level alarms and very low-level tripping device at least once a week. When the water level goes very low, the tripping device shall trip the firing system/hot gases input to the boiler. 

An MCB of the type shown in Fig. 3.28 incorporates a thermal and magnetic tripping device. The load cument flows through the thermal and the... 

Tripping devices for a machine that require simultaneous application of both hands to operate the control, so that the hands of the operator are kept out of the point-of-operation area while the machine is operating. A two-hand-control device protects only the hands of the machine operator (and not other individuals) when used as a safeguarding device. See also Hostage Control Device. 

Finally, the effective operation of the test button incorporated within the RCD should be tested to prove the integrity of the mechanical elements in the tripping device. This test should be repeated every 3 months. 

Used where frequent transfers made between discrete fixed points. Normally follow a fixed route with guide wire let into the floor and travel at a controlled speed. Main precaution is the provision of a trip device fixed to the front of the tovdng truck such that the truck with full load will stop before the main body of the truck reaches any obstruction it meets. 

Finally, the size or at least the orientation of a conveyor may require operators to be in the vicinity of the conveyor but far firom the drive and its controls. Emeigency trip devices should be provided wherever this presents a hazardous situation. Since most conveying systems have multiple members, a trip of any one membo- should automatically shut down others, at least on the upstream side. 

Vendor to include tripping devices/switches for emergencies, e.g. fire, jattuning, chain break. 

Mechanical risks may be engineered out of the process, or effectively enclosed by means of fixed guarding. Alternative forms of guarding involve the use of interlocked guards, light-sensitive barriers or pressure-sensitive mats. Trip devices and other forms of emergency stops may also be incorporated. 

A trip device ensures that an approach to a dangerous part beyond a safe limit stops or reverses the machine (Figure 26.18). These devices should be arranged so that they are actuated involuntarily by the movement of the limb into the danger area. Trip devices include trip bars and wires, sensitive probes (for radial drills), photoelectric devices and pressure-sensitive strips and mats. In use it is important that trip devices are properly adjusted and that the machine s brake is in good working order. Emergency stop wires,... 

No. PM 10 Tripping Devices for Radial and Heavy Vertical Drilling Machines... 

Use of simple safeguarding devices fixed and adjustable interlocked guards trip devices... 

Use of advanced guarding systems interlocks and trip devices for pneumatic and hydraulic machines application of risk assessment methodologies and reliability engineering principles to complex guarding systems. 

PM 10 Tripping devices for radial and heavy vertical drilling machines... 

Trip on demand only Reduction in nuisance trips Device self diagnostics Multi-drop architecture Installation flexibility Asset management tools Cost reduction... 

Figure 12.15 Schematic diagram of a telescopic trip device fitted to a radial drill.

A trip device does not physically keep people away but detects when a person approaches close to a danger point. It should be designed to stop the machine before injury occurs. A trip device depends on the ability of the machine to stop quickly and in some cases a brake may need to be fitted. Trip devices can be ... 

A trip device is used to start the machine automatically when paper is fed in. 

Where mains voltage has to be used, are trip devices, e.g. residual current devices (RCDs), provided for all equipment ... 

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