Chapter 1 Dredging Instruments
2.1.1.1 General
Dredge dredging construction is an underwater operation, the construction personnel can not witness the underwater situation, and in the construction process is affected by many variables, randomness is great. Therefore, dredging equipment to timely grasp the progress of dredging construction, effective control of dredging construction quality, improve dredging construction efficiency, has a pivotal role, is to realize the necessary means of scientific dredging management.
Dredging instrument is used to detect, convert, display, control dredging process parameters, process parameters of the instrumentation, including the configuration of the peripheral equipment or auxiliary equipment. Nowadays, radio locators, tide level telemeters, etc. are also included in its scope.
The main instruments of the dredger are shown in Table 2.1.1-1
Table 2.1.1-1 Dredging Instruments for Dredgers
|
Ship Type |
Dredging Instrument Name |
|
Bucket Wheel Dredger |
Mud pump automatic controller, suction vacuum indicator, discharge pressure indicator, concentration meter, flow meter, production meter, draft loading monitor, longitudinal and transverse tilt indicator, bucket depth and position indicator, dredging process monitoring system, radio positioning device, electronic chart display system, bucket wheel winch automatic controller, etc. |
|
Cutter Suction Dredger |
Mud pump automatic controller, vacuum level, discharge pressure indicator; concentration meter, flow meter, production meter, cutter depth and position indicator, cutter monitoring and automatic controller, dredging cross-section monitor, integrated automatic dredging control system, lateral movement automatic control, etc. |
|
Bucket Chain Dredger |
Automatic Mud Dredging Monitoring and Control System (including automatic adjustment or display system for bucket bridge and winch cable release and retrieval) forward distance indicator, mud bucket rotation speed indicator, etc. |
|
Grab Dredger |
Grab Depth Indicator, Grab Opening Degree Meter, Grab Lifting Speed Meter, Grab Load Meter, Grab Machine Rotation Angle Indicator, etc. |
|
Bucket Dredger |
Digging Depth Indicator, Boom Rotation Angle Indicator, Aft Pile Inclination Angle Indicator, Bucket Handle Backward Angle Indicator. |
2.1.1.2 Basic Composition of Dredging Instruments
Dredging instruments can usually be divided into three parts: sensors, measurement circuits and display instruments (see Figure 2.1.1-1). The majority of dredging instruments on dredgers apply non-electrical measurement techniques. Non-electrical measurement technology includes electrical measurement technology, automatic control technology, microelectronics technology, computer technology and sensor technology, etc. It is a combination of many advanced technologies, and its main feature is reflected in the sensor technology.
1.Sensor
Sensors are the primary link in the realization of automatic data detection and automatic control. Its role is to solve the dredging process of non-electrical control and the detected amount of media. Will be external, time-varying non-electrical physical quantities into electrical quantities, which occupies a very important position in the dredging instrument, the accuracy of the information it obtains is related to the accuracy and reliability of the entire instrument.
2.Measuring circuit
Measuring circuit is to process, transform and convert the output signal of the sensor into digital quantity, and transmit the digital signal to the microprocessor through appropriate interface. In the dredging instrument, more types of measurement circuits, such as bridge circuits in the analog circuit, phase sensitive circuits, operational amplifier circuits, etc.; in the digital circuit there are gate circuits, logic circuits (including a variety of triggers), digital / analog and analog / digital converter. Application of which circuit depends on the choice of sensor type.
3. Display device
The display device is used as a display of results, some are called display instruments. In dredging instruments usually appear in three forms of display: one is analog display, such as pointer type meter a milliampere meter, voltmeter and so on. The second is a digital display, such as digital voltmeter, digital counter, digital frequency meter. The third is the image display, it is displayed on the CRT screen to detect the results or the measured parameters of the change curve and other images.
In the dredging instrument in the role of the microprocessor or microcomputer in addition to processing these digital quantities of information, but also a better solution to the application of sensors in the nonlinear and dynamic characteristics of the compensation, to improve the performance of the instrument to measure, display or record the results of the output processing to facilitate the monitoring of the dredging process, real-time control of the quality of the construction of dredging; but also the output of the digital quantity of the control information, through the interface of the digital-to-analog converter, converted into Analog signal, control or manipulation of dredging equipment corresponding to the actuator (some direct control with digital signals); can also have automatic control range, automatic calibration, self-searching fault judgment, or automatic indicators of judgment and sorting, as well as logical operations, into the quantitative control and program control. It can be seen, containing microcomputer (or microprocessor) dredging instrument has three main links: one is the sensor output into a digital quantity; two is a reasonable interface circuit; three is the preparation of a reasonable application software.
