Automation and remote control features have been developed in recent years for nearly every major area of the engineering installation. Systems have been designed for specific types of equipment, and are then operated even though other areas of the installation have no automation capabilities. There are automated controls for boilers, electrical plants, distilling plants, and many other lesser areas of the overall installation.
One of the most recent efforts has been in the control of throttle operation. Systems have been developed which permit throttle control from both the bridge and the engine room. With the advent of these throttle systems, the result has been centralization of all control capabilities into one location. This action is designed to serve two purposes, the decrease in watchstanding personnel and closer control of the engineering plant. Bell log printout capabilities have been incorporated for accuracy and time saving purposes.
Common plant monitoring systems, which cover all areas of the engineering installation, have been incorporated into a central location. They constantly monitor the areas of plant operation that are of importance to the watchstander, and incorporate printout features to log all conditions as required. Audible and visual indications are received when abnormal conditions exist in the system.
These consolidated plant developments have caused some confusion in understanding the concept involved, and in the training of operator personnel. The novice, for example, finds it very difficult to understand the program’s unfamiliar terminology. What is termed an automated propulsion system in one installation may not apply in another.
Complete automation of the engineering plant has not yet been attained on existing naval vessels, and much of the plant operation must still be handled by watchstanders actually doing the work. The automated plant as installed on board the combat store ship (AFS)-class vessel is probably the most advanced unit presently employed in the Navy. This unit can serve as a standard by which to measure automation as it is applied in other installations.
The AFS installation’s control booth houses the combustion control console, generator and power distribution controls, throttle control, a plant monitoring unit including printout features, and switches for remote operation of valves and equipments. Outside of the booth itself is the Bailey 760 Burner Management system, which is a part of the combustion control system, and on the bridge is a throttle control console.
This installation is designed to function under a normal steaming watch of five to seven qualified watchstanders. The control booth personnel include the watch officer, the throttleman, the boiler watch, and the generator electrician. Two or three roving watchstanders will perform all functions outside of the control center.
The basic systems that make up this installation are not difficult to understand. The electrical control system employs remotely-operated breakers mounted in the main switchgear and are controlled from the console. The meters and indicators necessary for plant operation are also installed on the console. Generators can be placed into service and governed remotely once the turbine has been started at the local station. The speed and voltage output of the generator is managed by regulation elements with control features at the console. Manual and automatic regulation capabilities are incorporated for maximum flexibility under casualty conditions.
The equipment used in the electrical plant control installation does not differ greatly in its operation from that previously used in remote control consoles. The operation status of the turbine generators, like all other engineering equipment, is monitored on the centralized performance monitoring equipment.
Throttle operation is controlled through a closed loop system with the initial signal generated at one of two locations. The main control is located in the engineering space. The bridge console can control the throttle only through engineering. This control can be shut off at any time by the engine room personnel. There are three means of controlling the throttle valve—a regulated electrical mode, a direct electrical control mode, and a manual mode of valve positioning. The regulated mode of control employs feedback information from various sources which, when compared to the control signal, maintains the shaft r.p.m. at the desired value. The direct mode of throttle control employs the watchstander to close the loop through manual switch control of the pilot/drive motor. The pilot/drive motor, depending upon its application, may either position the throttle valve or control a hydraulic positioning unit. Trigger signals are supplied to a logic unit which generates a printout of the bell log automatically.
Similar signals are used to cause desired changes in valve position and equipment operation (i.e., circulating valves, guard valves, and pump motors). Alarms and special features such as “bursting” are also an integral part of the system. The bursting feature is designed to stop the shaft and prevent the windmill effect when zero r.p.m. is requested. The shaft is stopped by applying short bursts of steam to the turbines to oppose the shaft movement when the r.p.m. exceeds a given value. The entire throttle control feature is an analog system, using variations in voltage values as the control element.
The monitoring of plant conditions for performance and alarm purposes is handled by an electronic unit. This assembly uses logic elements in order to provide digital display and log printout features. Analog indicators are also serviced by this system on all points from which information is considered vital. The entire system works on a timesharing principle and with inputs derived from bell log, alarm log display, and monitor signals. Signals from sensors enter the console as analog values and are converted into digital values for display and printout purposes. Display units are updated at two-second intervals, and the entire sensor complex is checked every six seconds to monitor all aspects of the plant.
Switches and indicators used in remote control of valves and auxiliary equipment are mounted on the consoles of the monitoring unit. Audible and visual alarm indications are provided.
A combination of electronic and pneumatic controls is employed in the combustion and feedwater control system. The pneumatic system employs the same elements and principles as used in previous combustion control systems. Pneumatic sensors, relays, selectors, and controllers are used to automatically keep the system in balance for all load requirements. Measurement inputs of all major areas in the system are computed, and the proper output signal is then sent to positioning devices used to control valves and dampers to provide proper combustion and feedwater ratios for boiler operation. The pneumatic system provides a more sensitive control than individual manual action and the boiler operation is more efficient. This system provides for automatic and remote control of the entire system, or of individual portions of the system. Indicators necessary to monitor plant operation are also provided at the control console.
The 760 Burner Management system uses electronic units to monitor the pneumatic system and various other boiler function. The input signals are used for various computations, which in turn initiate the action required. The system functions to control burners, purge boilers, detect flame, control the ignitor, and monitor the entire boiler operation. Again, audible and visual alarms are provided at the control console. Boiler trip features are also a part of the system and can be activated manually at the control console.
The various equipments in the installation are linked together through the alarm monitoring system, and remote control devices on the console provide another link between consoles. An AFS installation, for example, uses its plant performance and alarm monitoring system to provide the only service for the electrical plant equipment. Any alarm or status information pertaining to the ship service turbine generators would have to be obtained from the computer services console. The throttleman’s bell logs are printed automatically by this same equipment. The boiler console watchstander must also refer to the computer console for some of his equipment information. Main boiler stops, service valves, and various other functions of prime interest to the boiler watchstander are also located on the service console. The number of electrical elements used in all equipment consoles make this ship service power operation a matter of interest to all watchstanders. The throttleman, for example, must go to the services section of the console to make changes in his plant status, required by changes in modes of operation. Main circulating valves, circulating pumps, and discharge valves all have their remote controls located on the services console, and common interior communication equipment are used by all watch stations.
The engineering installation on the LKA-class vessel employs the same control capabilities as the AFS class. There are differences in design and operation of most equipment, but the same basic principles are employed in both installations. The greatest difference is in the performance monitoring equipment. The equipment on the LKA follows the same design principles found in previous monitoring systems. The performance installation is separated into three systems—gauges, bearing temperature, and alarm systems, and has no provisions for logging of plant conditions.
The gauges on the console are serviced by individual circuitry—a transducer at the sensing point produces an electrical signal which positions the gauge indicator—and each gauge operates independently of all other systems on the console.
The bearing temperatures are monitored and alarmed through a display panel on the console.
Temperature readings are obtained from individual sensors by a push button on the display. The push buttons have built-in visual alarm lights, and audible alarms are also provided.
The alarm system is made up of individual modular circuits similar to those previously employed in alarm monitoring systems. Each circuit operates independently, but all use the same audible alarm units. Illuminated displays on the module face plate provides visual indications of alarm and circuit trouble conditions and a four-position switch controls circuit operation. All modules use a common power supply and one of three audible alarms; each alarm denotes a given circuit priority. The alarm system is capable of servicing 101 sensing points.
The electrical plant controls are also basically the same as the previously described remote control adaptations. The major difference is the generating units. Two turbine generators and two diesel generators are used on board the LKA. The electrical controls are not a part of the main console assembly as on the AFS. It is, however, a unit in the same area.
The throttle control system is nearly identical to the AFS installation in design and operation. An independent bell logger is used on board the LKA to print all information pertaining to the throttle operation. This differs from the multipurpose logging capabilities of the AFS installation.
Engineering plant automation, with the centralized watchstanding complex, provides the individual watchstander with more information. All orders pertaining to the engineering plants are received within this enclosed space. Each watchstander is aware of the action being taken by other watchstanders, enabling better performance.
The knowledge requirements for a qualified watchstander will also be affected by this centralization. Each watchstander is now a part of a very close-knit team. However, the installation’s flexibility is proportional to the versatility of its watchstanders.
As these new systems prove their reliability under all operating conditions, watchstanding requirements will decrease, releasing more personnel for maintenance purposes. Systems using various degrees of automation are being placed in all new constructions projects. Greater degrees of sophistication will be established in the future, including the use of logic units to replace some of the operator functions. Diesel plants on the new destroyer escort and landing ship, tank-class vessels will also be automated to some degree. Developments will be made in casualty control features so that corrective action may be performed automatically. The days of complete manual operation of naval engineering plants are gone.