ISO 20662:2020 download free.Ships and marine technology Hopper dredger supervisory and control systems.
ISO 20662 describes the supervisory and control system for a number of components, functions and systems that can, but do not have to, be installed on board of a hopper dredger. It does not prescribe that all described components, functions and systems need to be installed.
1 Scope
ISO 20662 specifies the components and structure, general requirements, and functional requirements of trailing suction hopper dredger supervisory and control systems.
It is applicable only to the installed components, functions or systems. It covers design, manufacture and modification.
2 Normative references
The following referenced documents are referred to in the text in such a way that some or all of their content constitutes requirements of ISO 20662. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8384, Ships and marine technology — Dredgers — Vocabulary
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 8384 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
4 Components and structure
4.1 Components
A hopper dredger is a self-propelled dredger with its own integrated hopper hold.
An HD-SCS, according to ISO 20662, is a basic system for supervising and controlling the dredging operations performed by a hopper dredger utilising sensors, networks, computers, and technologies concerning measurement, communication and automation.
An HDSCS is an integrated SCADA system that can consist of the following subsystems, based on their functions.
a) STPM/STWC: STPM/STWC monitor excavation process. It should involve the monitoring and control of the suction tube, gantry, draghead, winch, swell compensator and other equipment. The STPM/STWC includes the suction tube vertical/horizontal angle, visor angle, swell compensator position, and valve/gantry state sensors.
b) DSLS: DSLS monitor loading process. It should involve the monitoring and control of overflows, light mixture overboard valve, loading valve and other equipment. The DSLS includes the dredger draught, hopper level, trim/heel, mixture density, mixture flow, overflow position, and valve state sensors.
c) Unloading system: unloading system monitor bottom dumping, rainbow/shore discharging process. It should involve the monitoring and control of the bottom door, split-system pre-dumping door, hopper emptying valve, bow coupling and winch and other equipment. The unloading system includes the bottom door position, pre-dumping door position, and hopper emptying valve state.
d) Dredge pump system: the dredge pump system should involve the monitoring and control of the dredge pump, including pump vacuum and pressure. pump speed, and pump power.
c) Jet water system: the jet water system should involve the monitoring and control of the jet pump, hopper jet water valve, and draghead jet water valve. The jet water system includes the jet water pressure, jet water flow, jet pump speed, jet pump power, hopper jet water valve state, and draghead jet water valve state sensors.
f) Dredge valve system: dredge valve system construction of mixture channel for dredging operation. it should involve the monitoring and control of the dredge valve.
4.2 Structure
The HD-SCS should adopt a multi-layer network structure, including equipment layer, process monitoring layer, and information management layer, as follows:
a) equipment layer: field instrumentation/sensors;
b) process monitoring layer: PLC, signals collecting and processing units, communication network;
c) information management layer: central monitoring and control station.
5 General requirements
5.1 Operating position and control mode
5.1.1 Operating position
The HD-SCS should have local and remote operating positions.
6.1.2 Operation
The STPM/STWC should have the following functions for the equipment operation:
a) hoisting/lowering of the trailing suction tube(s);
b) controlling of gantries;
c) adjusting of the visor angle;
d) stroke and pressure regulation of the swell compensator.
6.1.3 Controller
The STPM should have a STWC, which makes winches and gantries of the suction tube and swell compensators to work together to move the suction tube to a specified position or to hold the position, especially to ensure a constant dredging depth of the draghead.
6.1.4 Display
The STPM should display the following information:
a) top view, side view, and back view of the suction tube with relation to the dredgers position;
b) depth of draghead. and horizontal distance between draghead and hull;
c) status of the suction tube in seated position;
d) stroke of swell compensator;
e) position of the gantry.
6.1.5 Alarm
The STPM should give the alarm under the following circumstances:
6.2.2 OperatIon
The DSLS should have the following functions for the equipment operation:
a) open/close of the light mixture overboard valve;
b) open/close of the loading valve;
c adjusting of the overflows position.
6.2.3 Controller
The DSLS should have a LMO, which makes some dredge valves to work together to achieve the right mixture to flow overboard or to flow into the hopper according to the velocity and density of the mixture.
6.2.4 Display
The DSLS should display the following information:
a) draught, displacement, light weight, loading, trim;
b) loading mixture density, loading mixture flow;
c) hopper level, mixture volume in hopper, load;
d) position of adjustable overflow;
e) curve of hopper level, mixture volume in hopper, load.
6.2.5 Alarm
The DSLS should give the alarm when draught is over the pre-set value.
6.2.6 Calibration
The actual light ship weight can be calibrated in the LJSLS.
The unloading system should display the following information:
a) opening of bottom door, and pre-dumping door;
b) draught
hopper lank
d) discharge mixture density, discharge mixture flow;
e) status of rainbow winch, push ring, safety pin;
Q opening of the water inlet valve;
g) opening of the hopper emptying valve.
6.3.4 Alarm
The unloading system should give the alarm when the discharge mixture density is too high or when
the discharge mixture flow is too low.
6.4 Dredge pump system
6.4.1 OperatIon
The dredge pump system should have the following functions for the equipment operation:
a) start, stop, speed regulation, etc. of the dredge pump;
b) operation of dutch, reduction gear box, inverter of the dredge pump;
c) start, stop, speed regulation, etc. of the gland pump.
642 Controller
The dredge pump system should have a dredge pump controiIet which, by regulating the dredge pump speed, continuously ad justs the velocity of the dredged soil with regard to the maximum average density in the discharge pipeline, in this mannet a sufficient velocity of the discharge mixture is maintained.