High efficiency radial flushing for circular and small rectangular tanks

The Challenge

Most flush­ing sys­tems avail­able on the mar­ket for cir­cu­lar and small rec­tan­gu­lar tanks are uneco­nom­i­cal in com­par­i­son with the con­struc­tion costs. These tanks have to be cleaned man­u­al­ly, espe­cial­ly when there is no elec­tric pow­er at hand. Cir­cu­la­tion pow­er units (mix­ers), which can only be pow­ered elec­tri­cal­ly, coun­ter­act the sed­i­men­ta­tion process for which the tank is designed.

The Solution 

The Hydro­Self^® Tank Flush for cir­cu­lar and small rec­tan­gu­lar tanks is a con­tain­er-ised flush­ing sys­tem. It is placed on a base plate with cen­tral guide col­umn to which the con­tain­er guide and reser­voir enclo­sure are con­nect­ed. The cir­cu­lar out­er wall on the Hydro­Self^® pro­vides the water stor­age reser­voir. The size of the reser­voir will depend on the size of tank to be cleaned. The fill­ing occurs by means of a flap valve near the ground or by a fill­ing pipe or by the stored storm water flow­ing over the top of the unit and fill­ing the cen­tre reser­voir. After impound­ing, the retained com­bined water is sit­u­at­ed in the flush con­tain­er ready to be released once the storm tank is emp­tied. The shape of the out­er reser­voir wall per­mits the retained water to assist with the lift­ing of the cen­tre unit which, when trig­gered, will allow the water to flow under the retain­ing con­tain­er. The cen­tre reser­voir con­tain­er is opened by means of float tech­nol­o­gy or ultra­son­ic detec­tor, then the whole con­tain­er wall is raised and a radi­al flush wave occurs.

The Functional Principle

Phase I — Dry weather
In dry weath­er the storm tank is empty.

Phase II — Stormwater
When it rains the cir­cu­lar atten­u­a­tion tank is filled. The float which is posi­tioned in the receiv­ing sump sig­nals the flush­ing unit to lock the clo­sure mech­a­nism of the reser­voir. The flush­ing con­tain­er is filled via the flap valve pro­por­tion­ate to the water lev­el in the atten­u­a­tion tank. Even with par­tial fill­ing there is enough flush­ing water
in the con­tain­er to pro­vide a rea­son­able clean­ing wave.
Alter­na­tive­ly the storm tank fills to a lev­el that ful­ly charges the reservoir.

Phase III — After stormwater
After a storm event the tank emp­ties, leav­ing the flush­ing water retained in the reser­voir con­tain­er. The slop­ing wall of the reser­voir cre­ates an upward force due to the shape of the out­er wall. When the flush­ing sump is emp­tied, the float falls and unlocks the reser­voir container.

Phase IV — Flushing
Once unlocked, the force of water against the out­er reser­voir wall rais­es the whole con­tain­er upwards releas­ing the water in a pow­er­ful flush­ing wave. The water flows over the whole tank floor re-mobil­is­ing the set­tled debris and trans­ports it to the receiv­ing sump leav­ing the floor clean.

The Advantages

• auto­mat­ic fill­ing, even with par­tial inflow
• float tech­nol­o­gy with no exter­nal pow­er so no oper­at­ing costs 
• elec­tro-hydraulic con­trol optional
• opti­mal clean­ing results even with heav­ier deposits
• no addi­tion­al con-struc­tion tech­nol­o­gy necessary
• durable
• man­u­al flush­ing possible
• flex­i­ble fitting

Cost effectivenes

• very inex­pen­sive
• oper­a­tion with­out exter­nal pow­er 
• retro­fit possible –
• even through small manholes
• low main­te­nance
• oper­a­tional­ly safe