Elevator controls

In the event of fire within a building, the controller for each elevator should isolate all manually operated inputs and return automatically to the evacuation level, usually the ground floor. An output from the building fire alarm panel is hard wired to the elevator controller, giving the signal for a fire condition. The elevator remains disabled at the evacuation level and the car doors open. If a fire officer requires control of a elevator a key switch or break-glass unit should be used to re-activate the elevator. 

Figure 13.11 Structure formula of 10H39+ and its operation as a molecular elevator controlled by acid-base inputs.

Fig. 46. A modern film balance. 1, torsion wire control 2, sweep control 3, sweep holder 4, trough 5, sweep 6, fioat 7, mirror 8, calibration arm 9, head 10, main torsion wire 11, gold foil 12, wire for mirror 13, elevation control 14, guide 15, traverse. From ref. 1.

Elevation Control. Elevation was controlled in the diffusion chambers by a 42-inch butterfly valve, electrically operated. The valve design included a raised seat for the butterfly. This valve, at times, opened to a certain point, then fluttered with such force as to break the driving linkage. Eventually the valve was removed from the line, the raised seat machined out, a new butterfly installed, and heavier driving mechanism provided. 

An aircraft has three controlling surfaces to regulate these three movements (see Figure 12-18). The elevators control the pitch of the aircraft. They are located in the horizontal tail section. The ailerons control the roll of the aircraft, whereas the rudder controls the aircraft s yaw from the vertical tail section. The other parts of a typical aircraft are the cockpit, wings, fuselage, tail section, and flaps. 

Computer-based systems have become omnipresent commodities within our environment. While for a large variety of these systems such as transportation systems, nuclear or chemical plants, or medical systems their relation to safety is obvious, we often do not reflect that others are as directly related to risks concerning harm done to persons or matter as, for example, elevator control or mobile phones. At least we are not aware of the risk in our daily use of them. 

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