DE19955446A1 - Dosing unit acting as a reservoir discharges dissolved ingredient through membrane into surrounding flow of water under treatment - Google Patents

Abstract

A chemical medium dosing assembly simultaneously serves as or is linked to a storage tank. The dose application takes place via a permeable or semi-permeable membrane which is submerged in the medium as part of the dosing assembly. The dosing assembly is fixed to a rotating shaft with two bearings. Blades are fixed to the outside of the dosing unit. Water enters the tank holding a charge of solid chemicals which are progressively released in a dissolved and dosed condition via the membrane. The unit is rotated by the passage of a surrounding medium e.g. water.

Description

The invention serves the dosing of liquid or solid chemicals, e.g. B. for Neutralization of acids or bases, for the elimination of contaminants from wastewater, of precipitants and flocculants, of H donors for denitrification or Nutrient solutions for biocenoses, disinfectants and. State of the art for the above The applications listed are fully automated dosing devices consisting of Pumps, measuring devices and control loops. Use of this technique e.g. B. on Small wastewater treatment plants is due to high investment costs and the vulnerability to Malfunctions not profitable. With seasonal or operational long dosing breaks dehydration and blockages of lines and measuring devices are to be complained about. This Dosing stations therefore also require increased operating costs, which is small Attachments are not available. Accordingly, one is for such uses Inexpensive dosing device and a method that is as possible without moving Parts and use of electrical energy meter the chemical directly into the water and works largely self-regulating, desirable.

The aim of the invention cited in claim 1 is to avoid these disadvantages and a new, self-regulating dosing device for small plants, in which a essential trouble-free and cost-effective operation without the use of electrical Energy and moving parts is ensured to develop.

This is solved by the features stated in claim 1.

The dosing device uses the selective permeability of membranes for Chemicals and the static pressure of the stored chemical. That is the driving force Concentration gradient between the inside and outside of the membrane. From the Flow rate of the medium into which the chemical is to be dosed, and the resulting concentration gradient is thus self-regulating Dosage.  

Particular attention is paid to the selection of the permeable or semi used permeable membranes with precisely defined permeability for the respective chemicals to judge. In preliminary tests (in the laboratory), membranes available on the market (e.g. fine sieves, membrane for microfiltration or semi-permeable membrane) on your Permeability and other parameters (resistance, etc.) for the respective chemical checked.

Solid chemicals are dissolved by the penetration of the medium (e.g. water) and then transported through the membrane.

Since the dosing device or parts thereof are immersed in the medium (e.g. waste water), Turbulence occurs, which is an additional interference of the metered chemical cause.

This is guaranteed by direct metering into the reactor chamber via the immersed membrane Prevent dehydration during long dosing breaks.

The dosing device is extremely inexpensive to manufacture and operate.

A further embodiment is specified in claim 2. This makes it possible rotate the dosing device through the flow of the medium (e.g. waste water) and thereby preventing the medium from settling or phase separation.

Embodiments of the invention are shown in the drawings and are in following described in more detail.

Show it

Fig. 1, the metering device ( 3 ), which is also used here as a storage container for the chemical, immersed in a reactor ( 2 ). ( 1 ) represents the inflow of the medium (e.g. waste water), ( 4 ) the membrane through which the chemical is dosed and ( 5 ) a connector between the upper and lower membrane.

Fig. 2 in the reactor ( 6 ) submerged metering device ( 3 ) with the membranes ( 4 ). In this example, the chemical ( 2 ) to be dosed is stored in a separate storage container ( 1 ). The medium (e.g. wastewater) enters the reactor through an inlet opening ( 5 ).

Fig. 3, the embodiment of the metering device explained in claim 2. ( 1 ) represents the metering device moved by the medium with the chemical to be metered, ( 2 ) the membrane, ( 3 ) a holder box and ( 4 ) the reactor chamber.

Claims (2)

1. Dosing device and method for dosing chemicals, wherein the dosing device is also used as a storage tank or is connected to one, characterized in that the dosing of the chemical takes place via a permeable or semi-permeable membrane, which is part of the dosing device in the medium is immersed. 2. Dosing device and method for dosing chemicals according to claim 1, characterized in that

• - The dosing device is movably mounted horizontally on a shaft and two bearings
• - Additional wings are mounted on the outside of the metering device.