SE502814C2 - Liq. dispensing means for effluent or sewage chemical treatment processes - Google Patents

Abstract

The appts. for the addn. of measured amts. of liqs. esp. to a process vessel in an arrangement for the intermittent chemical purificn. of sewage or water effluent, comprises a chemical liq. container; a dispensing device which is filled under its own pressure by means of a reverse valve when lowered into the container; a compressed air source such as a fan which is linked via a second valve to the liq. dispenser; and an accumulator tank connected by a pipe to the compressed air source. In a first position the second valve allows the compressed air source to supply an air overpressure to the liq. dispenser which forces out a measured amt. of liq. into the accumulator tank for subsequent transfer to a treatment vessel.

Description

01 CD I O G3 _. \ .Lä .2.

The operation of the dosing device of this invention is described in the following with reference to the accompanying figure.

The tank 19 is filled with an increase chemical which is to be supplied to the process notch 2 in a certain amount to the batch of process water which the invention prescribes. When the slope period starts and lasts> 75 minutes, the valve (Vll) pulses out a short sequence of lu fl, which is passed through line 23 to the dosing device 29. Because it is immersed in the surrounding liquid and the line 23 has previously been ventilated to the atmosphere, liquid has flowed into the dosing device 29 through the non-return valve and filled the device.

When the air is supplied, the non-return valve closes, the pressure is raised and presses over the trapped amount of chemical to the accumulator 21. A certain amount of lu fl will accompany the liquid, but this is ventilated to the atmosphere via line 1 6. the valve (Vll) shuts off the air supply, while new liquid flows into the dosing device 29. The procedure is repeated.

Because the displaceable tube 18 has been positioned in a position where the distance from the lower edge of the tube in the accumulator 21 to the switch-off level of the level sensor 28 constitutes the desired amount, the pulse to the valve (VII) will continue until the level switch 28 signals to the microprocessor , that the volume is reached.

The desired batch volume is now available in the accumulator 21.

When five minutes remain of the deposited oxygenation period in the process vessel 2, the microprocessor activates the valve (VI), which sends a long flow pulse / s through the line 24. The line 26 is blocked through the non-return valve in the lid 25.

An Iu overpressure is now applied to the liquid surface of the accumulator 21, and the whole amount of chemical contained in the accumulator 21 will be very quickly dumped into the process vessel 2, where mixing of the oxygenation liquor takes place, as previously described.

This part of the recovery enables good training to be achieved.

As the level of the liquid surrounding the dosing device 29 gradually decreases as chemicals are consumed, the time for filling the dosing device 29 and thus the accumulator 21 will increase. A maximum time set on the microprocessor activates an alarm function and a signal, which informs the maintenance personnel that the chemical container 19 will soon be empty and that a change should take place. Of course, no change in the dosage amount occurs, as this volume is controlled in a manner previously described.

Of course, this invention can also be used in other dosage ranges than the so-called SBR process indicated here. / the case occurring -3. only low pressures can be overcome by the relatively weak source of compressed air that the fan 8 constitutes.

However, there is nothing to prevent highly compressed air or other gas from being used as the working medium. The dosing container 19 does not have to be pressure-resistant, because even at a very high working pressure in the line 26, this container is protected by the non-return valve in the lid 25. A non-return valve in the line 18 protects the accumulator 21 against overpressure or over-temperature.

Claims (1)

AT TENTKRÅ V: Device for batch dosing of liquid, preferably to a process vessel (2) in a plant for intermittent chemical purification of waste water, characterized in that the device comprises a container (19) with a chemical liquid and a dosing device (29) arranged in this liquid ), which is refillable by self-pressure via a non-return valve and via a second valve (Vll) is connected to a pressure source (8), such as a fl genuine, and via a line (26) is connected to an accumulator tank (21), and that the compressed air source (8) is arranged to transfer a lye overpressure to the dosing device (29) at a setting position of the second valve (VIII) and press a dosed quantity of liquid from it over to the accumulator tank (21) for further transfer to a processing vessel, ). The device according to claim 1, characterized in that the accumulator tank (21) communicates with the processing vessel (2) via a riser pipe (18) and via a line (24) and a third valve (V1) with the pressure lock source (8) and that the connecting line (26) between the accumulator tank (21) and the container (19) can be shut off by means of a non-return valve and that the pressure valve (s) (8) is arranged to transfer a pre-set time via the third valve (V1) to the accumulator tank (21). air pulse, which is arranged to close the non-return valve of the connecting line (26) and cause a set of chemicals built up in the accumulator tank (21) to flow through the riser pipe (18) over to the processing vessel (2). Device according to one of the preceding claims, characterized in that the riser pipe (18) can be raised and lowered in the accumulator tank (21) and that it is provided at the top with a liquid level sensor (28) and that the distance between the level sensor (28) and the riser pipe (28) 18) opening in the accumulator tank (21) is adjustable for adjusting the size of the chemical charge. Device according to one of the preceding claims, characterized in that the accumulator tank (21) is transparent and graduated.