Bridge cranes

The pool walls will be examined using of the bridge crane. Equipment would be moimted on a table / platform hanging from the crane, the crane would then be used to traverse the equipment along the pool walls. 

It is proposed that the survey of the interior of the main hall will be carried out manually using hand held instruments. This will be supplemented using the bridge crane mounted equipment to examine the hall walls up to crane rail height. 

The main cell of the vitrification plant is provided with a 2-t bridge crane, eight shielded windows, and 14 manipulator positions. Every component in the plant is designed for remote discoimection and removal to an adjoining maintenance cell. 

International Standard ISO 8306 (1985) Cranes - overhead travelling cranes and portal bridge. Cranes - tolerances for cranes and tracks. 1st edn 1985-12-15, International Organization for Standardization. 

The biggest danger from a bridge crane during an earthquake is its derailment and its fall. 

For this reason, it is useful to ensure that the extremities of the bridge crane have welded steel sheet restraints (or equivalent structures) which are able to prevent derailment (see Fig. 15-18). A simple calculation shows that for a crane weighting 50 t (the weight of a crane is usually equal to its lifting capacity), and supposing that the lateral stops must resist a horizontal inertia force corresponding to 0.2 g with 0.5 m of lever arm, two welded steel sheet pieces 40 mm thick are sufficient. 

For the calculation of other stresses, the bridge crane model can be simplified as a distributed mass beam resting on its extremities with an additional mass at the centre submitted to a vertical oscillation complying with the floor response spectrum. 

The east west high bay has a 2-ton bridge crane that spans the north-south dimension of the building and travels east to west. A 1/2-ton jib crane is located outside of the east door to the... 

Table 2.9-1 lists the overhead crane/hoist assemblies permanently installed inside and outside the HCF, their primary functions, their rated capacities, and the typical load each assembly handles. There are 19 bridge cranes located throughout the HCF with one exception, each is equipped with a hoist. Each-bridge crane/hoist assembly is marked with the maximum load for which the assembly is rated. A rail system in the airlock is used to transfer large packages into and out of the Zone 2A canyon. 

Zone2A Canyon Bridge Crane for Waste Handling, General Material Handling and Maintenance inside the Zone 2A Canyon 4 Tons 400 lbs... 

Internal 2t bridge crane—for maintenance of small components, with hook access to a loading bay area and... 

The functional FMEA targets any subsystems that may exist within an entire system. The functional FMEA will evaluate each subsystem and attempt to identify the effect of any failures in these subsystems. The analyst not only looks for the possible effects of subsystem failures on the system as a whole but also examines the effect of such failures on other subsystems within the system. Although functional FMEAs are not as common as the hardware FMEA, their basic utility should not be dismissed. When a complex system (such as a nuclear reactor, an airliner, an overhead bridge crane, or a new robotic milling machine) consists of numerous secondary subsystems, each with its own set of supporting subsystems, the functional FMEA should be performed to ensure proper system safety evaluation at every level. 

To further understand the use of the FMEA, the following example of an overhead bridge crane will be evaluated. It is again noted that this analysis, as with other sample analyses discussed in this text, is provided only in an effort to demonstrate the utility of a specific system safety analysis tool. It is therefore superficial in presentation and will examine only a select few of the many possible failure modes associated with the overhead bridge crane system described here. 

Figure 10.2 The combination 10-ton/ 1.5-ton overhead bridge crane system.

For the purpose of this example, the following components of the 10/1.5-ton overhead bridge crane are considered passive and will not be analyzed in the FMEA ... 

At face value, on the basis of the information provided, the complexity of the system described above appears to offer numerous opportunities for critical single-point failures. Therefore, the analyst should begin the FMEA process by first attempting to identify any and all nonpassive components and/or subassemblies that, depending on the type or mode of failure, could possibly have an undesirable effect. Table 10.1 lists each identified subsystem and related components in the overhead bridge crane system used in this example. Once such a list has been developed, the analyst will find it much easier to evaluate each subsystem or component, its possible failure mode(s), and the resultant effect(s) of any failure. Also, subsequent FMEAs may typically be performed during the operational phase of the crane life... 

TABLE 10.1 Overhead Bridge Crane Subassembly Components... 

In any of these situations, a crane is required that has access to any position within the cell line. This usually takes the form of a bridge crane that spans at least one cell line or perhaps an entire building. 

Bridge cranes always have access platforms (with proper safety features such as railing, etc.), but normal operation is from floor level. Typically, control is by a set of... 

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