A DEVICE FOR PROPORTIONING LIQUIDS

Abstract: Proportioning device for liquids, in particular for mixing a concentrate with a dilutant, e.g. water, the concentrate (1) and the water (19) being supplied to a mixing chamber (6) via respective connection tubes. The water (19) is supplied to the mixing chamber via a regulatory valve (20), a three-way valve (9) and a connection tube (8), the mouth of which is located between the top and bottom of the mixing chamber (6). A further connection tube (7) extends upward from the top of the mixing chamber (6) or from a location between said top and the mouth of said connection tube (8) to the reservoir (10') for the diluted liquid, and a drain tube (22) (siphon-tube) is connected to the remaining branch of the three-way valve (9). The concentrate reservoir (10) is at a lower level than the reservoir (10') for the diluted liquid. The drain tube (22) has its free mouth at a level lower than the mouth of the water supply tube (8) opening into the mixing chamber (6). The regulatory valve (20) is indirectly affected by the amount of liquid in the reservoir (10') for the diluted liquid (1').

Description: A DEVICE FOR PROPORTIONING LIQUIDS This invention relates to a device for proportioning of a first and a second liquid. The device includes a mixing chamber connected with tubes to the two liquids which are to be mixed and a reservoir for the diluted mixture of liquids. One of the objects of this invention is a proportioner for liquids which is cheap to install and easy to maintain. In particular this invention is used for diluting a concentrate with water, alhough of course the invention is not limited to this specific application. The characterising features of the proportioning device according to the invention are that the base of the mixing chamber is connected to the first liquids reservoir by a connecting tube, that the second liquid is directed to the mixing chamber by a regulatory valve and two branches of a three-way valve through a second connecting tube the outlet of which is connected somewhere between the top and bottom of the mixing chamber, that a third connecting tube extends from a location between the top of the mixing chamber and the outlet of the connecting tube from the three-way valve to the top of the reservoir for the mixed liquids, and that a drain tube is connected from the third branch of the three-way valve, the reservoir for the first liquid being at a lower level than the reservoir for the mixed liquids, also, the open end of the drainage tube being at a lower level than the openings on the other connecting tubes, and the regulatory valve being activated by the quantity of liquid in the liquid mixture reservoir. Further features of the invention will appear from the subsequent patent claims as well as from the description below with reference to the attached figures. Figures 1 - 8 show different stages in the liquid proportioning sequence. Figure 9 is a cross-section through the three-way valve, and figures 10, 11 and 12 are cross-sections X, XI and XII respectively in figure 9. Figure 13 shows an alternative installation where the regulatory valve is activated by electronic sensors instead of by mechanical means. Figure 14 illustrates a modification of the mixing chamber enabling adjustment to provide different dilutions of the two liquid components. Liquid concentrate 1 is gravity-fed from a first reservoir 10 via a first connecting tube 2 to the mixing chamber 6. The mixing chamber has a level mark 6' which, in the chosen though not limiting example, indicates 100 ml., and the level of concentrate will lie approximately on the level mark 6' depending on the level in the concentrate reservoir 10. In the chosen though not limiting example the other liquid ' is water 19 which is supplied to the mixing chamber 6 through a regulatory valve 20, e.g. a solenoid valve, a water supply tube 21, two branches of a three-way valve 9 and a second connecting tube 8. Thus when water is directed into the mixing chamber 6, the predetermined volume of concentrate in the mixing chamber 6 will be carried up to a second reservoir 10' for the liquid mixture 1' by the water in a more or less diluted condition. From the figures it can be seen that the reservoir 10' for the diluted liquid is fastened by a swivel 13 to one end of a balance arm 14 which in turn is suspended from a hook 15. The other end of the balance arm 14 is attached through a length of wire 16 to a switch arm 18 which affects an electric limit switch 17, which in turn controls the regulatory valve 20. When the level of diluted liquid in reservoir 10' reaches a specific upper level, being between a lower and an upper limit value, the switch arm 18 will move to open the switch 17 and close the regulatory valve 20. The time required to fill the upper reservoir 10' for the diluted liquid is dependant on the volume of the reservoir 10' and of the water pressure, typically 25-40 seconds for about 3 litres of diluted liquid. The time required for the concentrate to flow from the concentrate reservoir 1 to the mixing chamber 6 is 1 - 2 minutes depending on the level in the concentrate reservoir 1 and the viscosity of the concentrate. The amount of water in the diluted liquid is therefore determined by the weight of the diluted liquid in the top reservoir 10' . The amount of concentrate added is determined, as already mentioned, by the amount of concentrate which automatically enters the mixing cham-ber. With the illustrated device a dosage accuracy of +_ 10% or better is achieved by simple means. In the chosen example, the concentration of the diluted liquid is 3%. As indicated in fig. 13, the means 14 - 18 in figures 1 - 8 may be conveniently replaced by electrical and/or electronic means. Thus, the reservoir 10' may be provided with upper and lower level sensors 25 and 26, respectively. These sensors may be of any conventional type such as float operated microswitches , inductive or capacitive elements or optical devices. The sensors 25 and 26 are connected via leads 27 and 28, respectively, to a detector and control unit 29, the output of which controls the functioning of the regulatory valve 20 in a manner analogous to that of switch 17 in figures 1 - 8. Using the mixing chamber shown in figure 14 it is possible to adjust the concentration of the diluted liquid within e.g. a range of 0 - 3%. To this effect, the tube 7 is selectively movable up and down in the mixing chamber 6 instead of being firmly fixed thereto. To obtain a fluid tight engagement between the chamber 6 and tube 7, tube 7 passes through a flexible sleeve 31 which at its lower end is attached to a short tube 32 protruding from the top of the mixing chamber, said tube 32 having a dimension greater than that of tube 7. At its upper end, sleeve 31 is surrounded by a screw-clamp 30 to position tube 7 relative to the mixing chamber. The position of the lower end 7' of tube 7 within chamber 6 determines the amount of concentrate in chamber 6. The filling sequence for the concentrate is initiated by emptying the mixing chamber 6. This emptying occurs automatically each time the top reservoir 10' for the diluted liquid is filled, by means of the drainage tube 22 which acts as a siphon through the already mentioned three- way valve 9. Thus the described proportioning .device also uses the principle of siphoning to ensure that the concentrate is dosed correctly. As shown in the figures 1 - 8 there is a third connecting tube 7 connecting the top of the mixing chamber 6 and the top edge of the upper reservoir 10'. It is important that the upper reservoir 10' is placed at a significantly higher level than the concentrate reservoir 10. The mixing chamber 6 is preferably placed so that the top of the mixing chamber 6 is just below the level of the bottom of the concentrate reservoir 10. To ensure that water is not forced into the concentrate reservoir 10, a one-way valve 4 is inserted into the first connecting tube *" 2. In addition there are two tubing clamps 3 and 5 placed on tube 2, though they do not have any significance for the understanding of the invention. The same applies to the clamp 12 placed on the drain tube from the reservoir for diluted liquid 10'. When the system is first started, the system is preferably tested without concentra.te in the mixing chamber 6, the clamp 5 thus being kept closed. This allows the upper reservoir 10' to be filled with water and checking of the regulatory valve 20 which should close when the reservoir 10' is full. The excess water which is in tube 7 will flow back to the mixing chamber 6 and ensure that it is partly emptied so that the water runs out through the second tube 8 via the three-way valve 8 and down the siphon tube 22. The remaining water in the mixing chamber 6 will be at the same level as the bottom end of the tube 8, which as earlier mentioned extends a certain distance into the mixing chamber 6. When concentrate flows into the mixing chamber 6, the concentrate will fill the air space in the mixing chamber. The concentrate must flow relatively slowly from the reservoir 10 to the chamber 6 because otherwise it would follow the water directly down the siphon before the siphon is broken. Flow restriction can be achieved by making the tube 8 of appropriate dimension, pref.erably of wider dimension than that of tube 2. The operational sequence is best explained by referring to the attached figures 1 - 8 together with the following table, where e.g. tO is the starting time 0 sec, tl=20 sec, t2=40 sec., t3=41 sec. , t4=42 sec. , t5=45 sec , t6=100 sec., t7=160 sec. These sequence times are given as non- limitative examples only. As earlier mentioned there is a three-way valve 9 used in connection with the present invention (see figure 9). It may consist of a conventional T-tube 21, where an inner tube 23 is passed through the top of the "T". This inner tube, typically of silicon rubber, is fastened to the T-piece at the mouth of a branch thereof by means of a small piece of locking tube 24 which is pressed into the tube 23. Thus water flowing from tube 21 is prevented from flowing out of tube 22.

Claims: CLAIMS: 1. A proportioning device for mixing of a first and a second liquid, comprising a mixing chamber (6) with connecting tubes (2,8) to the two liquids which are to be mixed and to a reservoir (10') for the diluted liquid, characterized in that the bottom of the mixing chamber (6) is connected to a reservoir (10) of the first liquid (1) ■ through a first connecting tube (2), that the second liquid (19) is directed to the mixing chamber through a regulatory valve (20) and two branches of a three-way valve (9) and through a second connecting tube (8) which exits somewhere between the top and bottom of the mixing chamber, that a third connecting tube (7) extends from the top of the mixing chamber or a location between the top of the chamber and the exit of connecting tube (8) in the chamber (6) to the top of said reservoir (10') for the diluted liquid, and a drain tube (22) (siphon tube) is connected to the free branch of the three-way' valve (9), the reservoir (10) for the first liquid being placed at a lower level than the reservoir (10') for the diluted liquid (1'), the open end of the drain tube (22) being at a lower level than the end of the second connecting tube (8) within the mixing chamber, and the regulatory valve (20) being activated by the amount of liquid in the upper reservoir (10') for the. diluted liquids. 2. A device as claimed in claim 1, characterized in that the reservoir (10') for diluted liquid (1') is suspended at one end of a balance arm (14), while the other end of the balance arm through a connecting link (16, 17, 18) activates a regulatory valve (20). 3. A device as claimed in claim 1, characterized in that the reservoir (10') for diluted liquid (1') is stationary and that the level of liquid in the reservoir at the highest and lowest levels is detected by two stationary sensors (25,26) which in turn activate the regulatory valve (20) through a detection and control unit 4. A device as claimed in claim 2, characterized in that the connecting link comprises a wire (16) which through a switch arm (18) controls a switch (17) which in turn activates the regulatory valve (20), e.g. a 5 solenoid valve. 5. A device as claimed in claim 1, characterized in that the three-way valve (9) is T-shaped, its two coaxial branches being vertical, the upper one of 10 which being connected to the drain tube (22) and the lower one -of which being connected to said second connecting tube (8). 6. A device as claimed in claim 1, 15 characterized in that the top of the mixing chamber (6) is at a level being approximately the same as that of the bottom of the first liquid reservoir (10). 7. A device as claimed in claim 5, 20 characterized in that it consists of a T-tube (21) being known per se, a tube (23), e.g. of silicon rubber, passing through the two coaxial branches of said T-tube, said tube (23) being clamped to the opening of one of said branches by means of a locking tube (24) which is pressed into said tube 25 (23).

Inventors: CAMPBELL-KELLY ADRIAN ROBERT, CAMPBELL-KELLY, ADRIAN, ROBERT
Applicants: RUMEN CHEMIE AG, RUMEN CHEMIE AG GLARUS
Application year: 1983
Main classification: B01F5
IPC codes: B01F15, C02F1