Introduction to the Centralsug System Essay Example

two to five procedures a day, which lasts between 2 – 15 minutes depending on system size.During the downtime of the pneumatic conveyance system, which occurs between aggregation times, all machinery is turned off. However, the garbage can still be loaded into the chutes at any time. When the collection cycle begins, the exhausters start and create airflow in the garbage conveyance pipe system. The central control panel then commands the first air recess valve to open. Once the valve is open, a verification signal is sent back to the central control panel. A powerful air-steam is created in the garbage conveyance pipe system, from the first air recess valve to the garbage aggregation station. This air steam must be strong enough to transport even the heaviest garbage constituents. Once a minimum air velocity has been established in the conveyance pipe, the central control issues an order to open the first garbage discharge valve on the corresponding pipe subdivision. When this valve opens, any garbage stored above it falls by gravity or suction into the garbage conveyance pipe and is transported by the air current to the aggregation station. After approximately 7 seconds, all garbage stored on that valve is discharged and the valve is closed. After a short interval, the second garbage discharge valve on the same pipe subdivision receives an order to open and the same process described in step 4 is repeated. This continues until all refuse discharge valves connected to the first pipe subdivision have been discharged, at which time the air recess valve is closed.After a brief pause, the order is sent to open the second air recess valve in

the relevant pipe subdivision and the process from step four is repeated. This is continued until garbage from all discharge valves in all conveyance pipe subdivisions has been collected. Throughout the cycle, only one valve is opened at a time, allowing each garbage chute to be emptied in sequence. Once the garbage arrives at the aggregation station, it is separated from the conveyance air steam in a centrifuge and compacted into attached containers. These containers are then picked up by a standard arm lift truck and transported to designated areas for emptying. The garbage aggregation station can be located in a separate building or section of another building, such as a car park, and includes air exhausters to create negative pressure in the underground pipes and centrifuges for separating the garbage from conveyance air steam. In Hong Kong Science and Technology Parks, three exhausters are connected in series, with two in use and one as a standby.The garbage containers used in Hong Kong Science & Technology Parks typically consist of two containers with a capacity to store 10 metric tons each, which are collected using an automated garbage collection system with a control panel consisting of a desk top computer with modem for distant control, command board for general operation, motor control panel, and container handling system. The conveyance air also requires filtering for odor control, with cassette bag type filters for dry filtration installed downstream of the air exhausters and activated carbon filters and water scrubbers utilized to remove odorous gases. Container transportation is also a consideration when installing the ARCS.To reduce local traffic from heavy vehicles, it is often preferable to locate the

aggregation station at the outer boundary of the installation. Fig.7 shows the Container Conveyance seven and the Diverter Valve, which is installed when multiple types of waste are being collected, such as recycling. In Hong Kong Science & Technology Parks, there are two containers - one for non-recycling waste and one for recycling waste - and the Diverter Valve ensures that each type of waste is directed to the correct container. Fig.8 shows the Pipe Network in HKSTP, where refuse transport pipes are made of unstained steel due to transportation of large amounts of garbage and high impact areas. The wall thickness varies according to the erosion factors in different parts of the system, and all parts are welded together. In HKSTP, there are two service tunnels where all utilities, including conveyance pipes shown in Fig.9, are installed.The Refuse Discharge Valves, also known as DV, are located on the cellar level of buildings and separate the perpendicular garbage chutes from the horizontal conveyance pipe system. Between emptying cycles, garbage is stored above the closed valve and falls into the conveyance pipe by gravity/suction when opened. Only one valve can be opened at a time, with control boxes in garbage valve suites verifying and executing orders transmitted from the central control panel. A storage section is located above the valve in HKSTP, with a full-level detector alerting the control center to start the aggregation process. The Air Inlet Valves are situated at the end of each section of the garbage pipes on cellar levels near the final garbage discharge emptying cycles. The Refuse Chute and Refuse Inlet Doors are vertical garbage chutes within the building,

consisting of concrete or steel and providing recess doors for garbage disposal on each level with a slight negative pressure applied.The Refuse Inlet Door is volume controlled to prevent obstruction of garbage in the chutes and conveyance pipes. The dimensions of the disposed garbage should not exceed the inside diameter of the pipes. An exhaust fan is provided at the top of the chute for ventilation.

There are different configurations for the collection equipment depending on the purpose of recycling. The first configuration includes a main chute that serves all levels of the building for collecting non-recyclable waste on a daily basis. Ground level outdoor disposal recesses are provided for reclaimable materials such as paper or organic waste, which must be manually transported to specified recesses for collection. The second configuration provides full service for reclaimable waste disposal on each level of the building, allowing for disposal at the doorstep of each flat. Three different garbage chutes are used to collect different categories of waste.

As Hong Kong Science and Technology Parks is still under construction and Phase 1 is only 70% complete, Phases 2 and 3 have not yet started.The ARCS system is currently underutilized and produces only a small amount of waste per day. Despite this, Hong Kong regulations prohibit storing waste for long periods of time, and it would be inefficient to transport such a small amount of waste to a landfill. To address this issue, HKSTP is allowed to store up to 80% of the container's capacity before transporting it, as only dry waste is permitted in the system and odor is not a problem. Additionally, the ARCS can collect waste up

to 1 kilometer away and has the potential to replace manual waste handling, which can present hygiene concerns.