stormwater solutions - jacopa

Contact Jacopa: Tel: +44 (0) 121 511 2400 Fax: +44 (0) 121 511 2401 Email: [email protected] jacopa.com

Flushing System MF Vacuum

Key Features & Benefits:

• Can be installed in new designs or retro-fitted in existing tanks.

• Utilising storm water, without taking storage volume.

• Long Flushing lengths can be serviced—in excess of 100 m.

• No submerged moving parts.

• All serviceable parts accessible without entering the tank.

• Full flushing even after partial storm events.

How We Create Value:

• Very Low Operational Running Costs.

• Flushing lane widths up to 10 m.

• Minimal maintenance requirement.

• Circular and rectangular tanks accommodated.

• Long tanks can be serviced.

Stormwater Solutions


Due to increasing hydraulic loading within the sewerage systems, attenuation sewers and tanks are required to attenuate flows. This leads to the deposition of debris and silts within the construction.

The Jacopa MF Vacuum Flushing system is a highly efficient cleaning system to maintain the cleanliness of tanks and attenuation sewer constructions. This system has been designed to overcome the problems of cleaning storm tanks that cannot be designed to self-clean or where the use of conventional such as flushing gates, tipping buckets or jets would compromise health & safety or cost efficiency. The MF system can be used within either rectangular or circular tanks.

During a storm event, the attenuation tank starts to fill; the storage process encourages settlement of debris on to the tank floor. As the tank fills, the vacuum pump is started evacuating the air in the flushing chamber, thus drawing the water up into the chamber. (This can be raised to a level of 7 m if necessary). This allows the filling of the flushing chamber independently of the water level in the main tank. This means that a full flush can be achieved even with a partial fill of the tank.

Once the tank has emptied, the diaphragm valve is signalled to open allowing air in to the chamber which releases the captured flush water. The resulting surge of water efficiently cleans the tank floor and deposits the contents into the receiving sump.


Stormwater

Solutions




Flushing Sequence:

1. Start of storm : Tank Empty

2. Storm flows start to fill tank.

3. The vacuum pump is called to start. Drawing water into the flushing chamber until the maximum level is reached, at which point the pump is topped and the column of water is held by vacuum.



Stormwater

Solutions

Flushing Sequence (continued):

4. After the storm has passed and the tank drains down the flush water is held in the end chamber until required to be released.

5. The diaphragm valve is opened releasing the vacuum. The water surges down the tank re-suspending the settled debris and transporting the dirt to the receiving sump. The tank is cleaned with a single flush.

Circular Tank Layout:

Circular tanks can also be accommodated by the provision of a central column providing the flushing water storage vessel. With large circular underground tanks, this can be incorporated in the centre roof support structure.




Flushing Lane Design:

Tanks greater than 10 m in width can be divided in to two or more flushing lanes. The width of lane and thus volume of water is also tempered by the available volume of receiving sump. Multiple lanes can be flushed sequentially via the control panel.

Individual flushing lanes are to be separated by 50 Cm dwarf walls to contain the flush water within each lane. The initial 2 m of dividing wall should be 1 m high as the released water will spurt initially.

The tank fall should be 0.5 % at minimum and of good smooth construction.

Flush volume:

The volume required to flush a tank will vary due to number of lanes, length of tank, gradient and volume of receiving sump. It is recommended that Jacopa is consulted at the early stages of design so that this element can be calculated.

Design of Flushing Chamber Base:

In all cases the minimum width of the chamber should be 800 mm in case access is required for civil construction inspection at any time in the future.

Option 3

If the base of the flushing chamber including the siphon is formed as a single element. This extends down the tank at a slope of between 0.5 % to 2 % and can also include the formation of the receiving sump.

Option 2

If the base of the flushing chamber is level with the tank floor a concrete mound can be formed to create the siphon . This is method that can be utilised if retro fitting within existing tanks.

Option 1

The base of the flushing chamber is set below the tank floor to achieve the correct siphon dimensions.


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Stormwater

Solutions

Height of Flushing Chamber:

The height of the flushing chamber will depend upon the size of tank. The maximum potential head within a flushing chamber is 7 m; however, 4 t o5 m is more common.

Diaphragm Valve:

The Diaphragm valve is to be located at the top of the flushing chamber. An opening of 700 x 900 is required in the top of the flushing chamber and a minimum clearance of 300 mm is required around the opening to permit the plate to be installed centrally. The fixing surface should be level and smooth to ensure a good seal can be obtained.

Control Location:

It is recommended that the control panel and vacuum pump is located as close to the flushing chamber / diaphragm valve as possible. If it is not possible to locate adjacent to the flushing chamber, the control should be no more than 100 m away.

A single vacuum pump can be used for multiple diaphragm valves.

Electrical Supply:

The power requirement for the vacuum pump will vary depending upon the size of unit used / chamber size: 1.5 to 3.0 Kw is the usual range : 400 v / 50 Hz. Allowance for panel and kiosk services as appropriate.

Due to its rugged construction, the diaphragm valve can be fitted directly on top of the flushing chamber at ground level. Protection will be required for the hoses.

If the unit is to be mounted below ground level, then consideration is to be give to constructing a ‘man accessible’ chamber to enable maintenance to be carried out.

stormwater solutions - jacopa

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