CS270869B1 - Electronic dosing device of liquids' small quantities - Google Patents

Abstract

The electronic dozer of a liquids small quantities is designed for transport and dosing liquids into one and/or more mixing areas from several tanks. The basis of the dozer rests in the fact that it consists of tanks (6) filled with dozed liquids with a capillary inlet piping (9) discharged into a totalling element (1) and a programmable controlling unit (7) controlling three-way electromagnetic valves (5) connected with the areas above the dosed liquids in the tanks (6), while the space above the level of a selected dozed liquid is connected with the source (3) of a constant pressure of the gas through a distribution piping system (8). The dozer can be used primarily where there is a lack of direct access to the mixing elements and liquids are necessary to be dozed in closed separate spaces, and also if it is necessary to programme the dozing of liquids due to a line batching.<IMAGE>

Description

The invention relates to an electronic dispenser of small quantities of liquids from several containers into one or more working spaces.

The prior art solutions for dispensing small quantities of liquids utilize complex mechanisms to measure the volume and transport the dispensed liquid. Such dispensers can be divided into two groups depending on whether or not the dispensed medium comes into contact with the dispensing device. For example, piston dispensers are in contact with the medium, which directly push the metered suction medium into the metering line. The second method is dosing with peristaltic pumps. These do not have a dosing device in direct contact with the dosing medium and the dosing is dependent on the flow and time factor. The disadvantages of these structures are complex machine mechanisms, which are demanding on production capacities and used materials. These devices also have higher maintenance and repair requirements due to lower reliability.

The above-mentioned drawbacks are eliminated by the electronic dispenser of small quantities of liquids according to the invention, which consists of dispensers of dispensed liquids with capillary feed lines leading to the summation member located above the reservoirs and a programmable control unit controlling three-way solenoid valves connected to the spaces above and the space above the level of the dispensed liquid is connected to a constant pressure gas source via a manifold.

The invention of an electronic dispenser of small quantities of liquids allows the transport and dosing of liquids to one or more mixing spaces from multiple containers. It can be used especially when the hack is not a direct access to the mixing members and the liquids need to be dosed in enclosed separate spaces and also when the dosing of liquids is to be programmed for serial dosing.

An electronic dispenser of small quantities of liquids is documented in the attached drawings. Fig. 1 is a schematic diagram of the connection of individual members into a functional assembly; and FIG. 2 shows the theoretical flow characteristic of an electronic dispenser of small quantities of liquids.

In FIG. 1 is a constant pressure source 3 with an air reservoir 4, a pressure distribution line 8, three-way solenoid valves 5, dosed liquid reservoirs 6, capillary reservoir lines 9 mutually impeded to each other, the summation member 1 and the associated control unit 2. it ensures a constant gas pressure in the air reservoir 8 and in the manifold 8, even when the fluid withdrawal from this source changes. The three-way solenoid valves 5 in the idle position ensure the connection of the spaces above the dosing liquids in the reservoirs 2 of the dosing liquids with the atmosphere.

Actuation of the solenoid valve 5 by the control unit 7 starts the dosing of the medium. Via the solenoid valve 5, the working pressure is applied above the level of the dosing liquid in the reservoir which discharges the dosing liquid through the inlet capillary line 9 into the summation. from the rise time t _n at which the dosing liquid reaches the overflow mouth in the summation and from time t t, the actual dosing of the selected volume, as shown by the theoretical flow characteristic (Fig. 2). The rise times t _n together with the flow time characteristics for the actual metering device are stored in the memory of the control unit 7. The inlet conduit 9 having the nature of the capillary 2 is impeded to its length so that the rise ^time y t _n for the individual liquids is approximately equal. The liquid is dispensed by the control unit 2 by switching the solenoid valve to a quiescent state, whereby the space above the level in the liquid dispenser container is connected to the atmosphere, thus creating defined initial conditions for the careful activation of the container.

CS 270 869 B1

The accuracy of the quantity of liquid to be dosed is dependent on the accuracy of the specified start-up times t _n and the time flow characteristics entered in the control unit memory which can be tested and adjusted by means of correction programs before actuating the dosing device.

An electronically controlled small quantity of liquid can be used in analytical chemistry, biochemistry and related industries when precise dosing of small amounts of liquid is required.

Claims (1)

Electronic dispenser of small quantities of liquids, characterized in that it requires 20 zásob containers (6) of dosed liquids with capillary supply lines (9) leading to the summation (1) located above the containers (6) and a programmable control unit (7) controlling three-way solenoid valves (5), which are connected to the spaces above the dispensed liquids in the containers (6), wherein the space above the level of the 2-selected dispense liquid is connected to a constant gas pressure source (3) via a manifold (8).