DOSING ARRANGEMENT

Abstract: The dosing arrangement comprises two first pumps (1, 2) and (1, 2') for a liquid medium B whose pistons (1, 1') are mutually connected by a piston rod (12), and two other pumps (3, 4) and (3', 4') for a liquid medium A which are positioned outside in continuation of and coupled to the pumps for liquid B. The two pumps for liquid B are firmly fixed to a central body (5) which is hollow and filled up with liquid B, and in which are mounted two mutually connected suction valves (6, 6') which are activated by the pistons (1, 1') by means of a push rod (9) and switched over momentarily from one extreme position to another by a spring mechanism (fig. 7) and two exhaust valves (7) whose movements are derived from the valves (6, 6'). Furthermore, the central body (5) incorporates an opening/closing arrangement (figs. 2, 4, 6, 8 and 9), which can admit a variable volume of liquid B through a valve (36) into the cylinder for liquid A (4 or 4'), which is under a suction pressure, whereby the proportion of mix can be regulated.

Description: Dosing Arrangement DESCRIPTION The present invention relates to a dosing arrangement of the typed described in the introducing part of claim 1. From the description of Danish Patent No. 155656 is known a mixing plant for mixing one component, for example lubricating oil, with another com- ponent, for example gasoline, which drives a piston type liquid motor which in turn drives a crankshaft on which is mounted a rotating valve, which controls delivery and discharge of drive medium to two pistons in the liquid motor, and an impulse generator coupled to an electronic counting device. To one of the pistons or to both pistons is coupled a piston in a dosing pump by means of a compressible connection rod. The stroke of the piston in the dosing pump and consequently the performance of the pump can be varied by means of an adjustable stop or a stop screw mounted in the top of the cylinder in the dosing pump. The said known mixing plant does not seem to comprise means to prevent the liquid motor from stopping in an extreme position. This might be overcome with a flywheel, but there will still remain the problem of starting the motor from such extreme position. Furthermore, the shown rotating valve must have the effect - during the change-over operation - cause a slow-down in the speed of the closing for flow of liquid to and from the cylinders before there is a free flow again. This must give an uneven delivery and discharge of liquid, possibly with harmful liquid- hammer blows. Adjustment of the dosing operation by means of an adjust¬ able stop screw is not well suited if the dosing pump is to operate with high as well as low pressures. Furthermore, the said known system will give a periodic delivery of the liquid medium which is to be dosed. Furthermore, mixing plants are known in which a liquid medium A is dosed into another liquid B which flows through a pipe, and in which the volume of flow of liquid B is metered by a flowmeter, which could for instance consist of a turbine wheel giving electric impulses in relation to the volume of flow through the pipe. Other metering methods consist in a magnetic field being laid over the flowing liquid or sending ultrasonic signals through the liquid. But it does not always happen that the electrical conductivity or the sound-dampening character of the liquid medium permits the use of electro-magnetic flowmeters or ultrasonic flowmeters. The liquid flow is converted to an electrical signal which is an input signal to an electronic circuit whose output signal is used to control an electrically driven dosing pump, which could be an electric motor or a solenoid coil, which moves a piston or a diaphragm in the pump. The dosing accuracy is determined by the accuracy of the flowmeter. Many types of flowmeter do not, neither in theory nor in practice, live up to a linear relation between volume flow and signal emitted. If an accurate metering is needed it will be necessary to use flowmeters which are rela¬ tively expensive. These systems consist of several components, which have to be connected electrically or hydraulically to each other, and it will be necessary to have one or more electrical voltage supplies. It is a great drawback to have electrical components in a plant with flowing agressive chemicals or strong electrolytes, which easily penetrate electrical components and cause corrosion and shortcircuiting in the live components. It is the purpose of the present invention to describe a dosing arrange¬ ment of the kind described in the introducing part of claim 1, and which does not exhibit the drawbacks of the known dosing arrangements. This is achieved by embodying the dosing arrangement as described in the charac¬ terizing part of claim 1. According to the invention a dosing arrangement is composed in which the cylinder volume of the piston motor is filled with a liquid medium B. One charge gives a complete piston stroke and then the cylinder is evacuated and the process is repeated. This gives an close relation between the volume of liquid B which passes the motor and the number of piston strokes. The motor piston is coupled to the dosing pump piston, which is thereby given the same length of stroke. If the motor piston has the area A B and the dosing pump the area A A this gives a dosing D M which will be constant in the equation D M = A Λ A A + A B . The invention provides a technical solution to the problem of finding a simple way to vary the dosing D between D = 0 and D = D M , and how to adjust the dosing with infinite accuracy even in the case of very small doses. The valves controlling the liquid flow to and from the cylinders are activated by the direct action of the piston movement, and the change¬ over of the valves is instantaneous so that there is a full throughput in the inlet valve as soon as the belonging piston is in its bottom posi¬ tion, and through a outlet valve when the belonging piston is in its top position. This eliminates dead points, just as a maximum performance of the dosing arrangement is achieved. Claim 2 describes a preferred embodiment of a spring mechanism for the control of the valves in the liquid motor. Claim 3 describes a method of how to bring the sliding block past the centre position of the push rod, so that the inlet valves are closed instantaneously by spring force. Claim 4 describes special means whereby the movement of the outlet valves is coupled to the movement of the inlet valves. Claim 5 described an embodiment of an opening/closing arrangement which depends on the movement of the piston rod to deliver a variable volume of liquid B from the central body to the cylinder which is under suction pressure. Claim 6 describes a special embodiment of the recess in a plate which forms part of the opening/closing mechanism. Claim 7 describes another embodiment of an opening/closing arrangement. Claim 8 describes means for holding the piston rod in an unchanged rotary position, and Claim 9 describes a special embodiment of the recesses in a bushing, which is part of another embodiment of the opening/closing arrangement. The present invention is described in detail in the following with reference to the drawing in which fig. 1 shows a vertical diametrical section through an embodiment of a dosing arrangement according to the invention, fig. 2 shows a vertical diametrical section through a second embodiment of a dosing arrangement according to the invention. fig. 3 shows a partial section through a third embodiment of a dosing arrangement according to the invention, fig. 4 shows a section after the line A-A in fig. 1, fig. 5 shows a section after the line B-B in fig. 2, fig. 6 shows a section after the line C-C in fig. 2, fig. 7 shows a section after the line D-D in fig. 2, fig. 8 shows a section after the line E-E in fig. 4, and fig. 9 shows a section after the line F-F in fig. 8. As shown in the drawing figs. 1 and 2 the dosing arrangement comprises a liquid motor driven by the liquid medium B, which e.g. could be hot or cold water under pressure, and two dosing pumps for a liquid medium A, which could be a chemical, e.g. a cleaning agent or a disinfectant, which is to be dosed into liquid B. The liquid motor consists of a piston rod 12 common for two mutually connected pistons 1 and 1* moving each in its own cylinder, respectively 2 and 2 ' . Outside and in continuation of and coaxially with each of the cylinders 2 and 2' there is a dosing pump consisting of a piston 3, respectively 3', moving each in its own cylinder 4, respectively 4'. The pistons 1 and 3 and 1' and 3' are mutually permanently connected. They may for example be produced in one piece from the same stock mate¬ rial. The piston in a dosing pump therefore has the same length of stroke as the corresponding piston in the liquid motor. The cylinders 2 and 2' are located on opposing sides of and mounted on a central body 5, which has a delivery pipe 30 for liquid B and a discharge pipe 31. The cylinders 4 and 4' incorporate non-return valves 32 and 32' , which control the intake of liquid A from a pipe 33, and non-return valves 34 and 34' , which control the discharge of liquid A from the cylinders into the pipes, respectively 35 and 35', which are connected to the discharge pipe 31 from the central body 5. The central body 5 incorporates outlet valves 6 and 6' for delivery of liquid B to the cylinders 2 and 2' through inlet openings, respectively 6a and 6a 1 , and outlet valves 7 and 7' for discharge of liquid B from the cylinders 2 and 2' through discharge openings, respectively 11 and 11'. The valves 6 and 6" and 7 and 7' are embodied as seat valves. The valves 6 and 6* are mutually connected by a rod 8, and the valves 7 and 7' are mutually connected by a rod 10. The valves are moved in a direction pa¬ rallel with the direction of travel of the pistons 1 and 1* . The special control of the valves prevents dirt or calcium from fouling the valve operation. In the central body 5 is embedded a push rod 9, which can be displaced in a direction parallel with the direction of travel of the pistons 1 and 1' . The push rod is placed in such a way and with such a length that when one of the valves 6 or 6' is closed, it protrudes a short distance X into the belonging cylinder, respectively 2 or 2'. The push rod 9 is carried right through the central body 5 and through a bearing 14 in a sliding block 13 displaceably positioned on a surface in the central body. As shown in fig. 7 the connection rod 8 between the valves 6 and 6' is dis- placeably embedded in the sliding block 13. The sliding block has a width which is less than the inside distance between the valves 6,.6'. At each end the push rod 9 can be embodied with a sleeve 17, which for example could be screwed to the rod. At the end facing the sliding block 13 each sleeve 17 is embodied with a track 16 which takes up a spring 15, which is slid over the rod 9. The track 16 is of such a length that the spring 15 can be taken up in the track in the compressed state. The sleeves 17 are of such a length that when the rod 9 is in the neutral position where the springs 15 are not compressed they end a short distance Y from the side surfaces of the sliding block 13. One end of the sliding block 13 has its central portion embodied with slit 22 meshing with a pin 21 mounted on a counterweight 19. The counter¬ weight 19 is rigidly mounted on a pivot 20 located outside the sliding block in a centre line in the central body 5 and is pivotally embedded in the central body. At one end of the counterweight 19 opposite-the pin 21, the counterweight 19 is-in mesh with a pressure arm 23, which has a cyl¬ indrical pressure shoe 24, which is taken up in a track 26, which is shaped as a part of a cylinder in the end of the counterweight 19. At the opposite end the pressure arm 23 is swingably hinged to a piston 27, which can travel in a cylinder 28 and whose upper side is acted on by a spring 29. The pivot 20 is taken down through the central body 5 to a level a little above or a little below the connection rod 10 between the outlet valves 7 and 7' and which at the lower end has a bent part 20' . The rod 10 is em¬ bodied with two collars 37. These collars are located - and the folded part 20' has a length - so that the end of the part 20' can come to rest against one of the collars 37'"and bring the belonging valve 7 or 7' to an open position, when the belonging intake valve 6 or 6' is in the closed position. If for example the valve 6" is in the open position, liquid will flow into the cylinder 2' , whereby the pistons 1 and 1' are moved to the right. When the piston 1 nears the bottom position it will hit the end of the rod 9 which will thereby be displaced to the right. This will com¬ press first the spring 15 whereafter the end of a sleeve 17 comes to rest against the side of the sliding block 13 and displace it towards the right. The sliding block 13 will be displaced by the push rod 9 and move freely along the rod 8, until it is displaced a distance which is a little longer than half the travel of the block 13 from one extreme posi¬ tion towards the other. Hereafter the sliding block 13 will be influenced by the spring action of the springs 15 and 29 and will continue its travel in which it will first hit the back of the valve 6' and then dis¬ place the valve body 6,8,6', until the valve 6' is in its closed position and the belonging outlet valve 7' is opened, while the valves 6 and 7 be¬ longing to the cylinder 2 are in their open and closed position, respec- tively. Liquid now flows into the cylinder 2, and the pistons 1 and 1' are forced to the left until piston 1' hits the rod 9 and the valves change over once again. The way the dosing arrangement is described until now it can be con¬ structed to give an arbitrary, but regular dosing of a liquid medium A into another liquid medium B. To make possible a variable dosing of a liquid A into a liquid B the central body 5 incorporates an opening/closing arrangement, which over an adjustable length z of the length S of the piston stroke admits some of liquid B, which has passed the liquid motor, to the dosing cylinder, which draws liquid A from the pipe 33. There will be drawn liquid A only for a length of stroke of K = S - Z. The dosing proportion will thus be D = A 6 (S - Z)/(A α + A 6 ), in which A β = area of the dosing piston, and A x = areal of the piston in the liquid motor. Thus, D can assume all values between 0 and h & /A__ + A 6 . The system which supplies liquid B to the dosing cylinders 4 and 4' is in principle shown in figs. 1, 4, 8 and 9 and includes a valve 36, which is connected to the discharge pipe 31 for liquid B. When the valve 36 is opened, the liquid B can flow out into pipes 67 and 67' and taken through non-return valves 38 and 38' into the dosing cylinders 4 and 4' . These non-return valves have the effect that only liquid B will be let into the cylinder which sucks liquid A, and they prevent that the opposite dosing pump forces liquid into the pipes 37 and 37' . In order to make the valve 36 open for a variable length of the length of stroke of the pistons, the piston rod can for instance by its movement control an opening/closing arrangement for the valve 36. This can in principle be an arm or pin 39 mounted on the piston rod 12 and it can slide in a track 40 in the cen¬ tral body 5. The arm 39 also passes through a track 41 in a curved disc plate 42, which has a specially shaped recess 43. The curved disc can turn on a pin 44 in a fork 45 which carries a spindle 46, which by means of a set screw 47 can be displaced in the vertical direction. When the arm 39 moves from side to side the plate 42 will turn on the pin 44, and during its sideways movement it will hit the valve pin 36, which is forced forward by a spring. When the plate slides over the pin the latter is forced inward, and the valve 36 opens. The point at which the valve 36 opens during the movement of the piston rod 12 depends on the vertical position of the curved disc and of the shape of the special recess. The recess can be shaped so that there will be a linear relation between the vertical displacement of the curved disc 42 and the dosing. If the recess 43 is shaped as shown in fig. 8 it will be seen that when the curved disc 42 is at its lowest position, the valve 36 will remain open, and when the curved disc is in its top position, the valve 36 will remain closed. Be¬ tween these extremes the recess will give a relation between the vertical position of the plate 42 and the part of the travel of the piston rod 12 in which the valve 36 is open. The spindle 46 has a pointer 48 pointing on a scale 49. The reading indicates a supply determined by the curved disc of liquid B to the dosing cylinder, which is under suction pressure, and consequently a definite dosing. Depending on the shape of the recess the scale can be made linear or unlinear for the desired dosing. Figs 2 and 6 show an alternative system for the regulation of the dose by inlet of a desired and variable volume of liquid B from the central body 5 to the cylinder 4 or 4', which is under suction pressure. As shown in the drawing the piston rod 12 is carried through the pistons 1,3 and l',3', and the piston rod 12 is embodied as a pipe with an in¬ ternal hollow space 52, which is in connection with the cylinders 4,4' through non-return valves 53 and 53' , which are mounted one at each end of the piston rod 12. The piston rod 12 carries a sleeve 55 with a journal fit in the central body 5. The sleeve has a length, which equals approximately the width of the central body 5. The bushing is mounted in such a manner in the central body that it is held in place against side¬ ways displacement in the longitudinal direction of the piston rod 12, but that is can turn in relation to the piston rod, which is prevented from rotating as a guide pin 50 mounted e.g. on the piston moves in a bored hole 51 in the piston 4. The bushing 55 is embodied with one or more recesses 56. When a hole 54 in the piston rod 12 during its reciprocating movements is positioned in a recess 56 there is passage for liquid B from the central body 5 to the hollow space 52 in the piston rod 12 and from there through one of the non-return valves 53 or 53' to the cylinder 4 or 4' , which is under suction pressure. When the hole 54 is just outside a recess 56, the flow of liquid is barred from the central body through the hole 54. The recesses 56 are shaped so that the length Z of the piston rod's travel where a discharge of liquid is taking place, can be altered by turning the bushing 55. The recesses can e.g. as shown, have a shape as two identical right-angled triangles positioned at each end of the bush¬ ing, and where one side is parallel with the axis of the bushing 55 and the other is located in a plane close to the end of the bushing and at right angles to the axis of the bushing 55. The third side of the tri¬ angle will thus be oblique in relation to the longitudinal axis of the bushing, and a linear relation can be obtained between the dosing per¬ centage and the turning angle of the bushing 55. In the way the bushing 55 is embodied with recesses in both ends, liquid medium B will be delivered to the dosing cylinder 4 or 4' , which sucks liquid A at the beginning and end of the suction stroke. This is espe¬ cially desirable as piston or diaphragm pumps can have problems sucking the first liquid up into the cylinder if there is only air in the cyl- inder at the start-up. If no liquid is sucked in during start-up at the last part of the suction stroke, the liquid flowing through the hole 54 to the cylinder will fill the latter with liquid. This will instantane¬ ously solve the starting troubles of the dosing pump. Another advantage of the system is that at the end of a liquid dosing it is easy to clean the dosing cylinders by cutting off the liquid supply to the pipe 33 and let the liquid motor run for some time whereby the liquid, e.g. water, flows through the non-return valves 53,53' into the dosing pumps and clean them. In order to control the variable input of liquid through the hole 54 and obtain the desired dosing, the bushing 55 can be turned on the piston rod 12 by means of a worm 58 meshing with a worm gear 57 mounted on the centre of the bushing. By turning the bushing 55 and its recess 56 in re¬ lation to the hole 54, the lengths Z of the length S of the piston strokes, where the hole 54 is in a recess will be seen to be infinitely variable from the value Z = 0 to Z = S, depending on the shape of the recesses. The worm 58 can be turned manually with an attached knob 60, and its rotations can possibly through a gear arrangement make a pointer 62 point on a scale 63 showing the dosing percentage of liquid A in rela- tion to the volume of liquid B which suits the liquid motor. The worm 58 can also be electrically remote-controlled. The shaping of the recesses 56 can give a linear or unlinear relationship between the rotations of the worn 58 and the scale reading. As shown in fig. 3 the bushing 55 can also be immovably mounted, and the dosing can be varied by turning the piston rod 12 by turning a knob 64, which through a dog pin 65 is meshing with the piston 1' . As shown in figs. 1 and 2 it is also possible to mount pipes 66 causing a doubling of the volume of the liquid flow, and that the packings in the pistons are kept tight, even in the case of high pressures. Instead of pistons it is of course also possible to use diaphragms.

Claims: Ε»_i .'_C__-_N -V <__.T__.Α.__Z-XLS 1. Dosing arrangement for the dosing of at least one liquid medium A in¬ to another liquid medium B and which comprises a piston type liquid motor which is driven by liquid medium B and consists of two mutually connected pistons (1,1') on a common piston rod (12) which travel each in its own cylinder (2,2'), inlet and outlet valves for delivery and discharge of liquid B to and from the cylinders (2,2') and one dosing pump, but pre¬ ferably two dosing pumps for liquid A, each embodied as a piston pump consisting of two pistons (3,3') travelling each in its own cylinder (4,4'), which are positioned outside and in continuation of and coaxially with the cylinders (2,2') and which are mechanically connected to the pistons (1,1'), inlet and outlet valves for delivery and discharge of liquid A to and from the cylinders (4,4'), pipe connections for supply of liquid A from the dosing pumps to the discharge pipe from the liquid motor, and means for regulation of the proportion of mix, c h a r a c - t e r i z e d by the fact that the pistons (3) and (1) and (3') and (1') are mutually permanently connected and can for example be embodied in one piece, that the cylinders (2,4) and (2',4') are positioned each on its own side and attached to a central body (5), which has a width which is greater than the length of stroke of a piston (1) or (1' ) , in which the inlet valves (6,6") for delivery and the outlet valves (7,7*) for dis¬ charge of liquid B to and from the cylinders (2,2') are built in, that the valves (6,6') are embodied as seat valves, which are mutually con¬ nected by a rod (8) and can move in a direction parallel with the di¬ rection of travel of the pistons (1,1'), and which in their extreme posi- tions can close a delivery opening (6a) or (6a 1 ) to the cylinders (2) and (2'), respectively, that the valves (6,6') by means of the rod (8) can be changed over instantaneously from one extreme position to the other by means of a spring mechanism coupled to a push rod (9), which is displace- ably embedded in the central body (5) so that it can move in a direction parallel with the rod (8), and is placed and has a length so that when one of the valves (6) or (6 1 ) is closed, it protrudes a short distance (X) into the belonging cylinder, respectively (2) or (2') and is dis¬ placed by the piston, respectively (1) or (l 1 ), when the latter travels towards its bottom dead centre towards the central body 5, that the the valves (7,7') are embodied as seat valves which are mutually con¬ nected by a rod (10), which is parallel with the rod (8) and can move in a direction which is parallel with the direction of movement of the valves (6,6') and in their extreme positions they can close for the dis- charge openings (11) and (11') from the cylinders (2) and (2'), respec¬ tively, and that the movement of the valves (7,7') are firmly coupled to the movement of the valves (6,6'), that the central body (5) is hollow and filled with liquid B, and that the central body (5) incorporates an opening/closing arrangement which in correspondence with the movement of the piston rod (12) delivers a desired and variable volume of liquid B from the central body (5) to the cylinder (4) or (4'), which is under suction pressure. 2. Dosing arrangement according to claim 1 c h a r a c t e r i z e d by the fact that the rod (8) is displaceably mounted in a sliding block (13), whgich is displaceably positioned on a surface in the central body (5) and haβ a width which is smaller than the internal distance between the valves (6,6'), that the sliding block (13) in its extreme positions can come to rest either against a collar on the rod (8) or against the valves (6) or (6') and bring the said valves to a closed position, that the sliding block (13) is furthermore embodied with a bearing (14), in which the rod (9) is displaceable mounted, that the rod (9) on each side of the sliding block (13) carries a spring (15) whose one end can come to rest against the sliding block (13), and whose other end rests against the bottom of a track (16) in a sleeve (17) which is slid in over and attached to each end of the rod (9), that the sleeves (17) end a short distance (Y) from the side surfaces of the sliding block (13), and that the track (16) has such a length that a spring (15), in its compressed position, can be taken up in the track (16), whereby the end of a sleeve (17) can come to rest against the belonging side surface of the sliding block (13), that the sliding block furthermore is in mesh with a counter¬ weight (19) permanently mounted on a pivot (20) located in a centre line in the central body (5) and which through a pin (21) at one end is mesh¬ ing with a slit (22) in the sliding block (13), the said counterweight (19) at the other end meshing with a pressure arm (23) which at one end is embodied with a cylindrical pressure shoe (24), which is taken up in a track (26) in the counterweight (19) which is shaped as a part of a cyl¬ inder and at the other end is swingably hinged to a piston (27) which can travel in a cylinder (28), whose upper surface is actuated by a compres¬ sion spring (29) . 3. Dosing arrangement according to claims 1 and 2 c h a r a c t e r ¬ i z e d by the fact that the difference (X-Y) between the lengths (X) and (Y) is a little greater than half the travel of the block (13) from one extreme position to another. 4. Dosing arrangement according to claims 1 and 2 c h a r a c t e r - ized by the fact that the pivot (20) is carried down through the central body (5) to a level a little above or below the connection rod (10) be¬ tween the valves (7) and (7'), and that the pivot (20) at its lower end has a bent part (20') whose end can come to rest against two collars (37) on the rod (10) where the part (20') has such a length and the collars (37) so positioned that when one of the valves (6,6') is in its closed position, the corresponding outlet valve (7,7') is open. 5. Dosing arrangement according to claim 1 c h a r a c t e r i z e d by the fact that the opening/closing arrangement for the supply of liquid B from the central body (5) to the cylinder (4) or (4'), which is under suction pressure, comprises pipes, respectively (67) or (67') with built- in non-return valves, respectively (38,38'), which are connected to a valve (36) in the discharge pipe (31) for liquid B from the central body (5), which valve (36) has a valve spindle embodied as a spring-loaded pin, which is activated by a plate (42) with one or more recesses (43), which at its bottom is swingably hinged to a pin (44) in a fork (45) and which at the top through a vertical slit (41) placed vertically above the pin (44), is meshing with a pin (39) mounted on the piston rod (12), pre¬ ferably centrally between the pistons (1) and (I 1 ) so that the plate (42) is set in swinging motion round the pin (44) by the piston rod (12) whereby the valve (36) which is located vertically over the pin (44), is closed when it takes up a position in a recess (43) and is open when it is a position outside the recess, that the recess or recesses (43) are shaped so that the length (Z) of the travel of the piston rod (12) during which there will be a delivery of liquid B to the cylinder which is under suction pressure, can be varied by displacement of the plate (42) in re¬ lation to the valve (36), and that the plate (42) is displaceable in the vertical direction, e.g. by means of a screw spindle (46) with a set screw (47) whereby the location of the recess (43) in relation to the valve (36) can be varied, and that the vertical position of the plate (42) can be read on a scale (49) by a pointer (48) mounted on the fork (45). 6. Dosing arrangement according to claim 4 c h a r a c t e r i z e d by the fact that the recess (43) is shaped as an isosceles triangle located so that the connecting line between the pin (39) and the pin (44) is symmetry line or perpendicular in the triangle, that the height of the triangle is approximately equal to the length of the track (41), and that the valve (36) in one extreme position of the plate (42), where the pin (39) is in the bottom of the track (41), has a position either close to the base line of the triangle or close to the top position, and that the calibration of the scale (49) indicates the dosing. 7. Dosing arrangement according to claim 1 c h a r a c t e r i z e d by the fact that the piston rod (12) is carried through the pistons (1,3) and (l',3') and is embodies as a pipe with an inside hollow space (52), in which - at each end - is mounted a non-return valve (53,53'), which opens when the pressure in the hollow space (52) is is greater than atmospheric, that the piston rod (12), preferably midway between the pistons (1) and (1') is embodied with e.g. a triangular hole (54) through which liquid B can pass from the central body (5) to the hollow space (52), that the piston rod (12) is held in unchanged position of rotation by a guide pin (50) which can for instance be mounted on the piston (1) and slide in a bored hole in the cylinder (4) or the central body (5), that on the outside surface of the piston rod (12) in the central body (5) is mounted a bushing (55) with a slide pass, which bushing (55) has a length which is approximately equal to the width of the central body (5) and is embedded in the central body (5) so that it is held sideways, that the bushing (55) is embodied with one or more recesses (56) which, when the hole (54) during the movement of the piston rod (12) is located in a recess, permits liquid B to flow from the central body into the hollow space (52), and that the liquid outlet is closed when the hole (54) is located outside a recess, that the recesses (56) are so shaped that the length (Z) of the travel of the piston rod (12) over which a flow of liquid takes place, can be varied by turning the bushing (55). 8. Dosing arrangement according to claim 7 c h a r a c t e r i z e d by the fact that the meanβ for holding the piston rod (12) in an un¬ changed position of rotation is provided by a guide pin (50), which could for example by mounted on the piston (1) and slide in a bored hole (51) in the cylinder (6). 9. Dosing arrangement according to claim 8 c h a r e c t e r i z e d by the fact that the bushing (55) is embodied with two identical recesses (56) located each at its own end of the bushing (55) and each shaped as an isosceles triangle, whose one side is parallel with the axis of the bushing (55) and whose other side is located close to the end of the bushing (55) in a plane at right angles to the axis of the bushing (55) in such a way that each triangle's top point is located close to the middle of the bushing (55), and that the bushing (55) at its middle has a worm gear (57) mounted which is meshing with a worm (58) which by a shaft (59) is connected to a turning knob (60), and that the shaft (59) carries a gear wheel (61) which by means of a toothed gearing is connected to a pointer (62), so that the position of the bushing (55) and thereby the volume of the dosing can be read on a scale (63) .

Inventors: BERKE-JOERGENSEN JOERGEN, BERKE-JOERGENSEN, JOERGEN
Applicants: BERKE JOERGENSEN JOERGEN, BERKE-JOERGENSEN, JOERGEN
Application year: 1993
Main classification: F04B13
IPC codes: B67D1, F04B9, F04B13