DD273499A1 - METHOD AND DEVICE FOR FLOW MEASUREMENT OF SUSPENSIONS AND EMULSIONS - Google Patents

Abstract

The invention relates to a method and a device for flow measurement of liquids, in particular suspensions and emulsions in the technical field, preferably 0.5 l / h to 2 000 l / h, as a basis for monitoring and control of process stages in the chemical industry, the food - and the pharmaceutical industry and laboratories. The flow rate is determined by measuring the transit time of a pulse in the form of a gas bubble between two measuring points. For this purpose, gas bubbles are generated in the diameter of the measuring tube of appropriate size in a bubble pre-chamber in a partial flow of the measuring liquid, then admixed in a bubble chamber the main flow of the liquid to be measured and passed in stable form through the downstream measuring tube. The measurement of the flow time of the bubble between two measurement locations on the measuring tube is made via opto-electrical converters with a corresponding evaluation unit. figure

Description

For this purpose I page drawing

Field of application of the invention

The invention relates to an ancestor and a device for measuring the flow of liquids, in particular suspensions and emulsions in the range of 0.5 l / h to 2 OOOl / h, whose application in the chemical industry, the food industry and the pharmaceutical industry and in laboratories is particularly suitable ,

Characteristic of the known state of the art

The measurement of suspension and emulsion streams in the technical field, mainly from 0.5 l / h to 2 000 l / h is a problem in the chemical industry, which could previously be solved only by the use of complicated equipment with great effort.

According to a known method, gas bubbles are introduced into the liquid to be measured and the Zoit measured, which requires a bubble to cover a distance between two measuring points.

The bladder method has the advantage in measurements of the flow rates of suspensions and emulsions that blockages caused by settling solid or ßalagbildungen not occur or exert any disturbing influence. In order to prevent sedimentation of solids and thus blockages of pipelines, the flow velocities in the corresponding pipelines must be adapted to the suspension properties.

In the literature, no evidence of the use of the bubble process in the technical field are known, since the method has the disadvantage of introducing the gas bubble in the measuring liquid so that the entire cross section of the measuring tube is filled in gloichmäßig.

At higher velocities, the formation of stable bubbles is difficult because they are broken by the kinetic energy of the liquid and thus can not be used for measurement.

There are a number of methods and devices known using the bubble method. The Areas of application are most frequently in medical fields for measuring the dosages of blood, medicines and the like. The flow rates of all ancestors are very low and are not for suspensions or emulsions

transferable.

Often the gas bubble is brought via cannula by hand or appropriate pumps in the measuring liquid. According to DE-OS 3334805 A1 liquid flows in the range of 0.001 to 0.5 l / h at a Meßrohrdurchmesser of 0.1 to

2.0mm In particular, a medical Doslergeräten measured. The gas bubbles are hereby added directly into the measuring tube.

Another method relates to measuring the flow rate of a liquid in a line of

particularly sensitive or sterile liquids (DE-OS 1934583). Here, the meter is once filled with gas, which is constantly reused as a recycle gas. The blistering takes place in an upstream of the measuring tube

Blasonkammer. For flow measurement of suspensions and emulsions, the known methods are not suitable because the Blasonzuführungsleitungen can easily clog by solid particles. Characteristic of all these known methods is that the possibility of using relatively small liquid flows

is limited, since it is not possible to introduce at high speeds stable gas bubbles in the liquid to be measured.

However, low speeds can not be used for suspensions because they cause settling phenomena Solid particles come. Object of the invention

The aim of the invention is a DurchflußB.mengenmessung in the range of 0.51 / h to 2000l / h for monitoring and control of technical processes with high Meügeauigkeit and low susceptibility.

Explanation of the essence of the invention The invention is based on the object, a method and an apparatus for flow measurement of suspensions and Emulsions, with the use of bubbles of a specific lighter, medium immiscible with the suspension

develop a discontinuing btw. Separating the suspension or an emulsion prevented and even at higher

Flow rates of the liquid to be measured can produce stable bubbles. According to the invention the object is achieved in that the bubble by a partial flow of the measuring liquid, with 0.1 to 1 m / s

the bladder chamber flows through, is formed and discharged through this partial flow in the same direction with the measuring liquid in this.

The apparatus for carrying out the method according to the invention is characterized in that in the interior of the Bladder chamber is arranged a cylindrical, bottom with an opening bladder prechamber, wherein the supply for

the medium forming the bubble at an acute angle against the flow direction of the measuring liquid in the

Bubble pre-chamber opens and has a fine adjustment in a known manner. The equivalent diameter of the bubble chamber is 2 to 3 times larger than the diameter of the measuring tube. The diameter of the bubble prechamber is equal to the diameter of the measuring tube and the length of the cylindrical part of Bubble prechamber corresponds to 3 to 4 times the diameter of the measuring tube. The bubble prechamber points in Direction of flow on a central opening of 0.5 to 1.5 mm in diameter. The gas is supplied via a lateral feed in the Bubble prechamber passed at an angle between 0 and 45 ° to the central axis of the bubble prechamber, the diameter of the Feeder is equal to that of the measuring tube. The length of the supply line is 2 to ofacho the diameter of the

Measuring tube.

For the formation of stable bubbles, the bubble chamber is passed through in the vertical direction and is at the liquid inlet and at the Liquid drain conical. The blister prechamber is off-center in the cylindrical part of the bladder chamber

arranged.

Stable bubbles that fill the cross section of the measuring tube even at high speeds are formed by in the Bubble chamber a partial flow of liquid to be measured passed over the bubble prechamber and the speed of the Liquid in the bladder prechamber is greatly reduced by the opening on the upstream side. This will be Settling phenomena of the solid of the liquid to be measured avoided. embodiment

The figure shows the measuring device for carrying out the method of flow measurement for carbonate suspension with a solids content of 18% for a volume flow rate of 2.5 to 50 l / h.

The measuring tube 1 is arranged in a housing 2. In the housing 2 are at an angle of 90 ° to the measuring tube 1 at predetermined intervals in the flow direction of the liquid Kanälo for receiving the radiation sources SO to S2 and the radiation receiver EO to E2. The measuring tube 1 is made of glass. It is preceded by the bubble chamber 4 with the therein bladder prechamber 5, wherein the diameter of the cylindrical portion of the bladder chamber is 3 times the Meßrohrdurchmessers. The bubble chamber 5 is with a 4-fold length of the Meßrohrdurchmessers carries on its inflow surface an opening 6 of 1 mm in diameter. Via a fine adjustment 3 and feed 11, gas is injected into the bubble prechamber, where bubbles 7 are formed periodically at intervals of 10 seconds and dispensed into the flame chamber 4. The lateral feed 11 has an angle of 45 ° to the central axis of Blasenkarr.ner 4, the length of the feed 11 is 5 times the Meßrohrdurchmesser.

The liquid to be measured flows in the direction of the arrow through the measuring tube 1. SO to S2 and EO to E 2 are arranged opposite, connected to the pipe ends 8 and 9 wei η inlet and outlet of the liquid. The radiation sources and receivers are constantly in operation. They are connected to the control unit 10, which simultaneously takes over the evaluation and display of the measured value.

When a bubble 7 passes through the measuring location SO / EO, the display is set to zero, when passing the measuring location S1 / E1 the counting is started and at the measuring location S 2 / E 2 the cycle time is stopped. If stubble bubbles get into the measuring tube 1, they are compensated by the circuit logic, the measuring process is not interrupted. For the selected measuring range from 0.5 l / h to 2000 l / h, measuring tube diameters of 3mm to 12mm are used.

Claims (7)

1. A method for flow measurement of suspensions and emulsions by introducing a bubble of a specific lighter and not miscible with the suspension or emulsion medium, in particular a gas in a measuring tube and measuring the time which the bubble for a distance between defined measuring points in Measuring tube is required, the bladder is produced in a bubble chamber with a diameter greater than the diameter of the measuring tube, characterized in that the bladder flows through a partial flow of the measuring liquid, dio at 0.1 to 1 m / s, the bubble chamber, formed and by this partial flow in the same direction with the measuring liquid is discharged into this. 2. An apparatus for flow measurement of suspensions and emulsions, consisting of a measuring tube with a path defining optical or electrical sensors, an upstream cylindrical, conically tapered to the measuring tube inlet bladder chamber and a shut-off by a fine adjustment feed for a bubble forming medium, in particular a gas , characterized in that in the interior of the bubble chamber, a cylindrical, provided below with an opening bubble prechamber is arranged, wherein the supply for the bubble forming medium opens at an acute angle opposite to the flow direction of the measuring liquid in the bubble pre-chamber and has a fine adjustment in a known manner , 3. Apparatus according to claim 2, characterized in that the equivalent diameter of the bubble chamber is 2 to 3 times greater than the diameter of the measuring tube. 4. Apparatus according to claim 2, characterized gekonnzeichnet that the diameter of the bladder prechamber equal to the diameter of the measuring tube urd the length of the cylindrical portion of the bladder pre-chamber is 3 to 4 times the diameter of the measuring tube. 5. Apparatus according to claim 2 and 4, characterized in that the bubble pre-chamber in the direction of flow has a central opening of 0.5 to 1.5 mm, preferably 1 mm in diameter. 6. Apparatus according to claim 2 and 4, characterized in that the lateral feed to the bladder prechamber an angle between 0 and 45 ° to the central axis of this and the diameter of the feed equal to that of the measuring tube corresponds. 7. Apparatus according to claim 2 and 6, characterized in that the supply of the fine adjustment to the bubble pre-chamber is 2 to 5 times the diameter of the measuring tube.