Liquid purification or separation – Processes – Separating
Patent
1993-11-17
1995-11-28
Dawson, Robert A.
Liquid purification or separation
Processes
Separating
210787, 2105121, 210 80, 210514, 210521, B01D 2126, B01D 2124, B01D 2102
Patent
active
054704898
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an inlet device for charging shallow grit chambers with waste water having a feed line into and a drain line out of, a rectangular tank.
The invention also relates to an inlet device for charging settling tanks.
The invention relates, on the one hand, to a method of charging such shallow grit chambers and also to a method of charging such settling tanks.
2. Description of the Prior Art
To separate grit from the waste water, grit chambers are used in a known manner in sewage treatment plants with the objective of obtaining a clean sand, i.e. a sand largely free of organic admixtures, regardless of variations in the waste water inflow. Common to these grit chamber structures of a very wide variety of designs is the fact that they exploit gravity (in the case of a shallow grit chamber) or gravity and centrifugal force (in the case of hydrocyclones and circular tanks) to separate grit from waste water. The advantage of the grit chambers last mentioned compared with those based on the pure gravitational principle, must, however, not be assessed too highly in relation to the sizing effect because of the relatively low radial acceleration. The grit is separated essentially under the influence of gravity. The circular and spiral movement of the waste water effected by the shape of these grit chambers is used primarily to convey solids into the grit collecting chamber.
The technological background to the construction of shallow grit chambers is that the mineral constituents down to a separation size of d.sub.p .gtoreq.0.1 to 0.2 mm are to be separated from the waste water, while the organic components are to be conveyed further to the downstream purification stages. For this purpose, shallow grit chambers are predominantly used. The shallow grit chambers are charged horizontally via a pipeline. In that case, to even out the flow, grids or baffle plates, which, according to Dr. -Ing. H. Patt (Institute for Water Usage, University of the Federal German Army, Munich, 1990, ISSN 0720-1273), do not, however, have any effect on the total retention factor, are often arranged in the inlet region. In the case of the horizontal flow through the shallow grit chamber, the organic particles contained in the waste water are then separated with the aid of gravity by means of the different settling rates. Depending on the amount of inflow, a grit chamber minimum length, which, according to Camp, can be determined by measuring the surface charging, is necessary for the settling process.
On the other hand, it is not denied that, in the case of settling tanks, it is known to feed them from a feed channel via a certain number of inlet pipes. In the case of a settling tank it is important to achieve a uniform and low flow as quickly as possible.
SUMMARY OF THE INVENTION
The object of the invention is to provide a structurally simple device for charging shallow grit chambers with waste water, on the one hand, and for charging settling tanks with waste water, on the other hand, by means of which device the grit chamber length required hitherto for the settling process can be reduced by up to 50% for the same feed rate, or, in the case of settling tanks, the hydraulic efficiency can be increased from 50 up to 90% for the same feed rate and tank size as before.
Surpisingly, this is achieved, according to the invention, in an inlet device for charging shallow grit tanks with waste water having a feed line into, and a drain line out of, a rectangular tank, by constructing the feed to the tank as an inlet chamber having a base plate on which a control plate extending over the entire grit chamber width and adjustable with respect to it is mounted and forms an adjustable outlet gap with a deflection cylinder arranged horizontally opposite to it.
This object is achieved in an inlet device for charging settling tanks, wherein the feed to the tank is constructed as an inlet chamber, at whose outlet a control plate which extends over the entire settling tank width an
REFERENCES:
patent: 3945920 (1976-03-01), Pazyc et al.
patent: 3972814 (1976-08-01), Pazyc et al.
patent: 4059529 (1977-11-01), McGivern
patent: 4886605 (1989-12-01), Herve210519
Felder Anton
Valentin Franz
Dawson Robert A.
Dishong George W.
Reifsnyder David
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