SU767528A1 - Method of continuously metering liquid - Google Patents

Description

(54) METHOD FOR CONTINUOUS DOSING OF LIQUID

one

The invention relates to methods for the continuous dosing of liquids and can be used, for example, in continuous analytical tetrometers and in liquid chromatographs.

There is a known method for dispensing a liquid, which includes the operations of alternating dosing and dialing each of the dispensers .10

The disadvantage of this method is that the sequential dosing operations of the pumps are separated in time, as a result of which the total flow of the dosing liquid 5 is distorted.

Closest to the technical essence of the invention is a method of continuous fluid supply, including the additional operation of simultaneous metering, with both metering devices operating with different changes of piston speeds t2j. , .. The disadvantage of this method is that it has a flow pulsation of 25 s, especially at the beginning of the end of the joint dosing.

The purpose of the invention is to reduce pulsation of the grain .30

This goal is achieved by the fact that a simultaneous dosing operation is carried out at equal and constant speeds of piston movement, and at the beginning of this operation one of the dosing units delivers fluid only to the dosing line, and the other only to the dialing line, and at the end of the operation, vice versa and switching fluid flows by overlapping equal flow sections of the dosing lines and the dialing lines.

The proposed method is implemented in the device shown in the drawing. FIG. a block diagram of an apparatus for carrying out the method; in fig. 2-5 shows the switching device; in fig. 6-9 shows the graphical dependencies characterizing the operation of the switching device and the device as a whole.

The device contains two dispensers 1 and 2, in which pistons 3 and 4 move reciprocally; ; thus ensuring the operation; dosing and dialing. The pistons are driven by two stepper motors 5 and 6. The switching device 7, which functions as a regulator, is connected to an electric motor.

I eat 8. The working volumes of the dispensers 1 and 2 through the switching device 7 are connected to the containers of set 9 and dispensing 10. The sequence of operation of the dispensers 1 and 2 and the switching device 7 is determined by the program-. orom 11.

The switching device 7 includes a fixed element 12 and a movable element 13. To prevent leakage of fluid, the touching surfaces of elements 12 and 13 are carefully rubbed into one another. In the stationary element 12 there are cavities 14-17, and in the mobile one there are throttle channels 18-23, the flow sections of which are equal.

The device works as follows. U .. -.

When the dispenser 1 dispenses the fluid through the switching device 7, which is open to it in the dispensing position, the dispenser 2 produces a set (Fig. 2). This is determined by the fact that the movable element 13 of the switching device 7 is in the right extreme position relative to the fixed element 12. In this position, the cavity 14 connecting the working volume of the dispenser 1 completely covers only the channel 18, and the liquid flows through the throttle channel 23, the cavity 17 to the dosing line and then is is the dosing capacity 10. At that time, the dosing unit 2 produces a set of a type-setting container 9 through the dividing line of the cavity 15, the throttle channel 20, the throttle channel 21, completely blocked by the cavity 16, and further into operation. rd volume of the dispenser 2, wherein the selected set of time shorter than the time of dosing. ; ...... At the end of the dialing process, the dispenser 2 is stopped, the dosage is switched on and within 10-20 seconds both the dispenser dispenses the liquid, and the dispenser 1 continues to dispense into the dispensing container 10, and the dispenser 2 dispenses the liquid according to the above nyTTf into the container 9. After 10–20 seconds of joint dosing, and the speeds of the pistons at the dosing units are equal and the pistons move uniformly, the programmer 11 delivers a control signal to the electric motor 12, by means of the second, the movable element 13 begins to move in 20–40 seconds to the left the position relative to the stationary element 12 (Fig. 3), the area of the flow area formed by the contacting throttle channel 18 and the cavity 14 overlaps with DOSIA Ovania and the area of the flow area formed by the contacting throttle channel 19 and the cavity 14 is opened, the set is As the flow area per metering is reduced, the flow area per kit for dispenser 1 is increased.

For dispenser 2, this process is opposite: the area of the flow area formed by the contacting throttle channel 21 and the cavity 16 overlaps per set, and the area of the flow section formed by the throttle channel 22 and the cavity 16 opens for dosing, as for the dispenser 1, the passage area decreases sections per set, the area of the flow area per metering increases by so much.

A necessary and sufficient condition for an unchangeable total flow is dispensing the liquid at any moment of switching, switching devices 7, when both dispensers are dispensed, equality and constant 0 sums of the areas of flow sections of the dispensing and set are shown (Fig. 4).

03. where is., Where. - changing in process

switching the cross-sectional area to the dosing formed by the adjoining throttle channel 18 and the cavity 14 for the dispenser 1; where the change is in progress

switching the flow area to metering, formed by contiguous throttle channel 22 and cavity 516 for dispenser 2,

1Nab, varying from the flow area per set, formed by the contacting throttle channel 19 and the cavity 14 for

dispenser 1;

varying the area of the flow section to the set formed by the adjacent throttle channel 21 and the cavity 16 for the dispenser 2.

Structurally, this condition is determined by the fact that the distance between

The center of the throttle channels 18 and 19, 21 and 22 are equal and, in turn, are equal to the distances formed by the side walls of the cavities 14 and 16. In addition, the diameters of the throttling channels 18-22 are equal. . In this case, i.e. at any moment, perscul: device 7 is very small, the flow is reduced by skitt, the metering liquids are supplied to the metering line 1, the feed to that flow is increased by as much

The 0 line is the doser 2, and the total flow remains unchanged.

FIG. 5 shows the position when the movable element 13 of the switching device 7 is in the leftmost position relative to

stationary element 12. In this case, for 10–20 s both dispensers are metered together, and dispenser 2 dispenses liquid from its working volume through cavity 16, which is connected only to throttle channel 22, then through throttle channel 23, cavity 17 - into the dosing line and in its capacity of metering 10, and the dispenser 1 dispenses the liquid from the working volume through the cavity 14 connected only to the throttle channel 19, then through the throttle channel 20, the cavity 25 into the line of the set and into the container of the set. 9.

After 10–20 s, the dispenser 1 is stopped, and the dispenser 2 continues to dispense the liquid into the dosing line, then the dispenser 1 is switched on a set, the set is made from the same set capacity 9, stopped, turned on on dosing and for 10–20 s both dosing units dose the liquid, and the dosing device 2 continues to dose to the dosing line, and the dosing device 1 doses the liquid to the same dialing line and container 9. After this time, the programmer 11 delivers a control signal to the electric motor 12, by means of which the moving element 13 of the switching valve troystva 7 begins to stir for 20-40 with time in the right end position (FIG. 2) sequentially passing through the middle position shown in FIG. 3, but from the opposite side.

At the moment of switching the switching device 7, the dispenser 1 begins to reduce the priming fluid into the line of dialing and to increase it to the dispensing line, and the dispenser 2, on the contrary, and the speeds of movement of the pistons are the same for both dispensers. Then another. 1020 s both dispensers dose the liquid together, with the dispenser 1 only in the dosing line, and the dispenser 2 only in the dialing line. Upon expiration of this r- Z)

-ABOUT

the time of the dispenser 2 is stopped; include a set, make a set, i.e. The system is returned to its original position and is ready to repeat the cycle (Fig. 6-9).

FIG. 6 shows the operation of the switching device 7 / Fig. 7 illustrates the operation of the dispensers 1 and 2 in the dosage and dialing modes; 8 shows flow rates of 6J ml / min, received alternately and simultaneously.

0 by dispensing liquid dispensers 1 and 2 into the dosing line; FIG. 9 illustrates the total and unchanged flow Q ml / min resulting from the graphical addition of costs,

5 shown in FIG. eight.

Claims (2)

1.Weksler M.K. Denisov S.S. Automation of chemical analyzes of solutions. M., Himi, 1956, p. 54. 2.Prospect firm Perkin-Elmer Chromatograph model 1220, translation, with. 6 (prototype). Quo & Ator i H dispenser / HaSop. Dozir sixteen I / R doiormoflj / z 76752.8 The degree was discovered with a help of the Prague sections VL Sotamopa / The degree otiryUg) nm area passing through la Volator g  (Oua.S iC I Subsidizes Dispenser i DoAotor Z Dials Subsidizes Hasupaem Drimet Hasupaem : .. 7 WITH Fig tc 9