熱烈祝賀本公司投獲香港特別行政區政府房屋署 2015 至2017 年度地下管線勘測定期合約 合約編號20130098,價值23,369,000港元。
FORWIN Site Investigation Engineering Ltd.
   
地下管線探測
地下帶水設備勘察工作
管道滲漏探測
地型測量
快速紅外線檢測
結構測試
   
   
  探測工程内容    地下帶水設備勘察工作
  Manhole Survey 沙井測量
High Pressure Water Jetting 高壓水力管道清洗
Closed Circuit Television Survey (CCTV) 渠道內閉路電視探測
Relining – Full Pipe Lining & Rehabilitation 全管及部份管道修補系統    
 

高壓水力管道清洗
High Pressure Water Jetting

The principle is the removal (by water under high pressure) of debris and silt, from drainage systems, cable ducts and other pipework, which prevents the particular pipe from performing the function for which it was designed.

The system works by a diesel engine or electric motor driving a diaphragm pump at a predetermined rate of revolutions to develop a given flow rate of water through a delivery hose. The pressure is built up in the hose-pipe, which is of wire braided high pressure specification, by attaching to the discharge point a JET HEAD. The jet head is an attachment that directs the water from the hose in a reverse direction to the delivery direction through small holes that are drilled in it. By thus restricting the flow, pressure is built up to produce the required energy, in the form of water jets, to break out the debris/blockage within the confines of the pipe.

Different configurations of jet head may be employed depending on the type and constituency of the debris to be removed. For example, loose silt in the pipe invert will require a high flow of water but low impact therefore a jet head will be selected that will fulfill this requirement i.e., fewer but larger holes. For hard materials, a high impact but low flow rate will be required so a jet head with smaller holes will be required.

The method of attacking the blockage is to insert the hose, with the jet head attached, into the pipe. Activate the power source to enable the pump to produce the required water flow rate through the hose. The force of the water being discharged through the hose and back through the jet head will pull the hose along the pipe. The operator will allow the hose to penetrate approximate 1 m into the drain and will then pull the hose back. The water jets from the jet head will flush the debris back into the manhole/entry point where it can be removed for later disposal. The operator will then allow the hose to penetrate 2m into the drain and pull back, again bringing the debris into the manhole/entry point for removal. The next penetration will be 3m then 4m and so on until the jet head exits into the next manhole or exit point.

The reason for the cumulative penetrations is that if the hose is allowed to penetrate too far into the drain/pipe, the debris being flushed to the rear will build up around the hose and eventually compact around it, trapping it in the drain/pipe.

Where possible the hose should be inserted in the down stream entry point and the cleaning action should be up stream. The reason for this is that the flow of the water down stream will aid the removal of the debris from the pipe into the entry point.

Contrary to common belief, the pressure reading on the pump gauge is purely the pump head pressure and not the pressure emanating from the jet head. Though the pressure inside the jet head is very close to that of the pressure gauge, at the instant that the water escapes from the confines of the jet head the pressure drops considerably. The jets of water will not damage the pipe material but will be able to break out scaling and debris from the pipe wall and flush to the entry point. The jets will however be able to damage human flesh and eyes. For this reason the power source must not be activated until the hose & jet head are safely inserted into the drain/pipe run and must be deactivated before the hose is removed from the pipe run.

Arising from the drain/pipe run can be removed from the entry point by hand tools or by vacuum pump according to volume and constituency, and disposed of to the relevant authorized tip site.

For single entry points of cleaning where there is no exit point a LANCE can be employed. This is a further attachment that is fixed to the delivery hose. It is a hollow steel rod that is screwed to the delivery hose and small jet heads are attached to this. These heads have a single forward facing jet that will produce the maximum energy equal to the pump head pressure gauge.

The operator inserts the lance into the pipe and pushes it slowly along the run. The force of the water jet breaks out the scale and debris. When sufficient arising is evident, the standard jet head (rear thrust) is employed to remove the arising from the confines of the pipe.

This method is particularly useful for the removal of water scaling in heat exchanger tubes and similar type pipes. It can also be utilized for the cleaning of run off holes in soakaways & stabilized slope drainage etc. It has proven to be very effective for the cleaning of grease and dirt from flat surfaces such as the floors of car parks, garages and bus depots.


 
高壓水力機械管道清洗器材 High Pressure Water Mechanical Cleaning Equipment   高壓水力管道清洗器材
 
工人進行清洗工作   工人進行清洗工作
     


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