DOSAGE EQUIPMENT

Abstract: Dosage equipment, which includes a peristaltic pump for the dosage of liquid. The set of hoses (17) of the peristaltic pump includes an upper piece (18) and a lower piece (19). The body of the pump includes an attaching piece (13), to which the upper piece and the lower piece can be attached.

Description: Dosage equipment The invention concerns a liquid dosage equip¬ ment provided with a peristaltic pump. By its means, liquid is dosed into a group of vessels displaceable relative the nozzles of the peristaltic pump. The equip¬ ment can be used in particular in laboratories in various systems of analysis. Peristaltic pumps have been used commonly for transfer of liquids in applications in which the require¬ ments of accuracy of the dose quantities are not so high. The use of a peristaltic pump in precise dosage apparatuses has been made difficult by factors related, e.g., to the elasticity properties of the hoses and to the rotor speed and acceleration, which cause differences between the doses, in particular if the pump stands periods of different lengths between the times of use. Now a dosage equipment provided with a peri- staltic pump has been invented which includes a peristal¬ tic pump with a detachable set of hoses and with means for attaching the set of hoses. The means of attaching comprise attachment pieces provided on the set of hoses and corresponding attachment pieces provided on the body of the pump. Further, the dosage equipment includes a carriage displaceable relative the peristaltic pump, the liquid being dosed into the vessels provided on the said carriage. The attaching means are preferably so- called fast-coupling means. The end pieces of the set of hoses are pre¬ ferably interconnected by means of an unstretched yarn, which prevents detrimental tensioning of the hoses. According to an embodiment, the end piece of the set of hoses is provided with a cam pointing at the hoses, and the fastening piece on the body is provided with a groove corresponding to said cam. The tension of the hoses should preferably be made adjustable, and most appropriately so that the tension of each hose can be adjusted individually. An embodiment of the invention will be illus- trated in more detail with the aid of the accompanying drawings, wherein Figure 1 is a schematical front view of the whole apparatus partly in section. Figure 2 shows section A-A in Fig. 1 as enlarged. Figure 3 is a partial sectional view B-B in Fig. 2 without a cassette of hoses, Figure 4 shows a detached cassette of hoses for the apparatus, and Figure 5 shows the section C-C in Fig. 4. The main parts of the apparatus are the station¬ ary part 2 of the peristaltic pump, the detachable hose cassette 3 of the pump, the displaceable vessel carriage 4 with its conveyor means, a built-in steering equipment 5, and a control equipment 6, all of them fitted in a frame 1. The peristaltic pump includes a rotor, which consists of a rotor shaft 7 as well as of readily re¬ volving journalled shafts 10 fitted outside the rotor shaft 7 axially between end flanges 8 and 9. The rotor shaf 7 is rotated by means of a stepping motor 11. The other end of the rotor shaft 7 is journalled in the body piece 12 of the pump. The body piece 12 further includes a counter- piece 13,attached to the side of the rotor, for fastening the hose cassette. The counter-piece has a plane upper face 14 and a plane lower face 15 as well as a locking groove 16 opening perpendicularly away from the rotor sha . The hose cassette includes three hoses 17 made of an elastic material, which are attached to the upper piece 18 and to the lower piece 19 so that hose portions which can be tensioned around the rotor remain between the said pieces. On the lower piece 19, the ends of the hoses 17 are attached to nozzles 20 that open downwards. At the lower piece, the hoses are passed through holes 21 (Fig. 5). Gliding of the hoses away from the lower piece towards the upper piece is prevented by means of limiters 22 attached to the hoses. The lower piece further comprises an upper face 23 resting against the lower face 15 of the counter-piece as well as a cam 24 resting against the locking groove. The upper piece 18 is box-like, and at the opposite sides it is provided with through holes 25 and 26 facing each other for the hoses 17. Inside the upper piece, the hoses are passed through tensioning pieces 27. The hoses are provided with limiters 28, which prevent gliding of the hoses through the tensioning pieces towards the lower piece 19. In the upper piece 1:8, the lower face 29 is made so as to rest against the upper face 14 of the counter-piece, and it is further provided with a cam 30 resting against the locking groove 16. The location of the tensioning pieces 27 in the direction of the hoses 17 relative the upper piece 18 is adjustable by means of calibration screws 29. The calibration screws are parallel to the hoses, and they revolve freely in the holes in the box with their head outside the box. The threaded part is threaded into the bore provided in the tensioning piece. The upper face of the upper piece is further provided with a transparent window 31 with graduation marks 32, by means of which the position of the tensioning pieces can be monitored. The upper piece 18 and the lower piece 19 are interconnected by two unstretchable yarns 33 parallel to the hoses 17. The lengths of the yarns have been chosen so that they barely permit locking of the upper and the lower piece on the counter-piece 13 so that the hoses are tensioned around the rotor. Owing to the yarns, it is, however, not possible to stretch the hoses unnecessarily, thereby causing deformations that change the pumping volume in the hoses. In the pump, it is possible to use hose cas¬ settes of different hose numbers and dosage volumes. The vessel carriage moves below the nozzles 20 along rails 34 parallel to the hoses 17. The carriage is displaced by means of a stepping motor 35, whose shaf rotates an endless belt 38, which is attached to the carriage frame 36 and which runs over the shaft 37. On the carriage 36, vessels 39 are placed in rows perpendicular to the direction of movement. Each row has a vessel facing each nozzle 20. Further, at the initial end of the carriage 36, there is a bleeding vessel 40 of a width equal to the width of a row of vessels. The vessel is attached to the carriage by means of a T-slot joint in the lateral direction, and thereby it can be easily removed and re¬ placed. The pump is programmed so as to dose into the bleeding vessel once before the beginning of the dosage proper. In this way it is made sure that there is no air in the hoses 17 and that the tension in the hoses has been stabilized to the level of the accelerations caused by normal operation. A detector 41 senses if the bleeding vessel is in its position on the carriage and gives a signal therof to the steering system of the apparatus. In view of identifying the location of the carriage, the frame of the apparatus is provided with detectors 42 and 43. The detectors 41 , 42 and 43 may be either mechanical, optical, capacitive, or magnetic. The de¬ tectors are connected to the electronics card 44 of the steering system. By means of the steering system, the dosage takes place automatically in accordance with the starting values and commands given. The necessary starting values and commands are given by means of the knobs 45 and controls 46 in the control equipment. Fig. 1 also shows the vessel 47 containing the liquid to be dosed, into which the free ends of the hoses 17 have been submerged. When dosage is started, a cassette of the de¬ sired sort is placed into the pump and the ends of the hoses are submerged into the vessel containing the liquid to be dosed. Dosage vessels of desired sort and the bleeding vessel are placed in their correct locations on the carriage. The dosage volume is adjusted to the desired level, and the initial commands are given to the apparatus. Hereupon the steering system checks that the bleeding vessel is in its place and that the carriage is in its starting location, wherein the bleeding vessel is placed below the nozzles. Then, the first dose is dosed into the bleeding vessel, and the carriage is shif ed one step at a time while dosing the prescribed doses row by row into the vessels. The steering system identifies when the carriage has reached its opposite extreme posi¬ tion, and thereat stops the dosage. Naturally, within the scope of the invention, the apparatus can be modified from the above. Thus, in particular the shapes of the pieces of the hose cassette and of the pump attaching pieces may vary. It is, however, preferable that the fastening is a so-called fast coupling, wherein the cassette can be placed in its position by just lightly tensioning the hoses. The fastening piece may also be placed elsewhere on the body piece of the pump, for example facing the end of the rotor. The carriage track may also be made such that along the track vessel carriages can be transported continuously through the apparatus. In principle, it is also possible to use a stationary carriage and a displaceable pump.

Claims: WHAT IS CLAIMED IS: 1. Dosage equipment for the dosage of liquid by means of a peristaltic pump into the vessels in a group of vessels, which said equipment comprises - a body of the peristaltic pump and a rotor (7; 10) fitted as revolving in said body, - a set of hoses (17), which can be tensioned around the rotor of the peristaltic pump and in which, at one end of the hoses, there are nozzles that open downwards, - attaching means for attaching the set of hoses to the body of the peristaltic pump, - a carriage, which is displaceable relative the peri¬ staltic pump underneath the nozzles and which contains a group of vessels into whose vessels the liquid is dosed, c h a r a c t e r i z e d in that the attaching means comprise - an attaching piece (13) fixed to the body of the peristaltic pump, - in the set of hoses (17), an upper piece (18), which is fixed between the ends of the hoses and which can be attached to the attaching piece on the body, and - a lower piece (19) , which is fixed to the set of hoses between the ends of the hoses and which can be attached to the attaching piece on the body, said lower piece being placed at such a distance from the upper piece that, when the upper piece and the lower piece are fixed on the attaching piece, the hoses in the set of hoses are tensioned around the rotor to the extent required for the peristaltic operation of the pump. 2. Dosage equipment as claimed in claim 1 , c h a r a c t e r i z e d in that the upper piece (18) or the lower piece (19) can be attached to the attaching piece on the body by means of a fast coupling. 3. Dosage equipment as claimed in claim 2, c h a r a c t e r i z e d in that the upper piece (18) and the lower piece (19) are interconnected by means of an unstretched yarn (33) , which is long enough so that it permits tensioning of the hoses to such an extent that the upper piece and the lower piece can be attached to the body piece (13) when the hoses (17) have been wound around the rotor, but which yarn is so short that it prevents unnecessary stretching of the hoses. 4. Dosage equipment as claimed in claim 2 or 3, c h a r a c t e r i z e d in that the number of the yarns is two. 5. Dosage equipment as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the attaching piece (13) is provided with a groove (16) opening from the rotor in the direction of tensioning of the hoses, and that the upper piece (18) and the lower piece (19) are provided with cams (30; 24) resting against the groove. 6. Dosage equipment as claimed in claim 5, c h a r a c t e r i z e d in that the number of the grooves (16) is only one. 7. Dosage equipment as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the upper piece (18) or the lower piece (19) is provided with hose tensioning means (27; 28; 29), by whose means the tensioning of the hoses on the rotor can be adjusted. 8. Dosage equipment as claimed in claim 7, c h a r a c t e r i z e d in that, by means of the hose tensioning means (27; 28; 29), the tensioning of each hose (17) can be adjusted individually. 9. Dosage equipment as claimed in claim 7 or 8, c h a r a c t e r i z e d in that the tensioning means include a tensioning piece (27) , which moves relative the piece (18/19) and parallel to the hoses (17) and to which the hose is attached (28) , as well as a screw (29) , by means of which the position of the ten- sioning piece relative the piece (18/19) can be adjusted. 10. Dosage equipment as claimed in claim 9, c h a r a c t e r i z e d in that the screw (29) re¬ volves freely in a hole in the piece (18/19) and that its threaded part is turned in a corresponding threaded hole in the tensioning piece. 11. Dosage equipment as claimed in any of the claims 7 to 10, c h a r a c t e r i z e d in that the tensioning means (27; 28; 29) are placed inside the upper piece (18) or lower piece (19) and that the piece is provided with a window (31), through which the location of the adjustable parts of the tensioning means can be monitored. 12. Dosage equipment as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the carriage (36) includes a bleeding vessel (40) , into which liquid can be dosed when necessary. 13. Dosage equipment as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the pump is placed stationarily and the carriage (36) is displaceable. 14. Dosage equipment as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the carriage (36) is displaceable along a straight track. 15. Peristaltic pump, which comprises a body and a rotor (7; 10) fitted as revolving in the body; a set of hoses (17) that can be tensioned around the peristaltic pump; as well as attaching means for attaching the set of hoses to the body of the peri¬ staltic pump, c h a r a c t e r i z e d in that the attaching means comprise an upper piece (18) fixed to the body of the peristaltic pump and attachable to the attaching piece on the body, as well as a lower piece (19), which is fixed to the set of hoses between the ends of the hoses, which can be attached to the attaching piece on the body, and which said lower piece is at such a distance from the upper piece that, when the upper piece and the lower piece have been attached to the attaching piece, the hoses in the set of hoses have been tensioned around the rotor to the extent required for peristaltic operation of the pump. 16. Set of hoses that can be tensioned around the rotor of the peristaltic pump, including attaching means for attaching the set of hoses to the body of the peristaltic pump, c h a r a c t e r i z e d in that the attaching means comprise an upper piece (18) , which is fixed at the side of the rotor on the body of the peristaltic pump and which can be attached to the attaching piece on the body, as well as a lower piece (19) , which is fixed at the set of hoses between the ends of the hoses and which can be attached to the attaching piece on the body, said lower piece being placed at such a distance from the upper piece that, after the upper piece and the lower piece have been attached to the attaching piece, the hoses in the set of hoses have been tensioned around the rotor to the extent required for peristaltic operation of the pump.

Inventors: HEINONEN MAUNO, KOIVISTO JUHA, PRIHA MATTI, TERVAMAEKI JUKKA, HEINONEN, MAUNO, KOIVISTO, JUHA, PRIHA, MATTI, TERVAMAEKI, JUKKA
Applicants: LABSYSTEMS OY
Application year: 1988
Main classification: B67D5
IPC codes: B67D5, F04B43, F04C5, G01F11