Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/12—Machines, pumps, or pumping installations having flexible working members having peristaltic action
  • F04B43/1207—Machines, pumps, or pumping installations having flexible working members having peristaltic action the actuating element being a swash plate

Definitions

• This invention relates to a pump of a peristaltic type, at which a medium to be pumped is fed in a conduit of an elastic material in such a way that suitably designed pressure means compress the conduit in a definite sequence and again release the pressure against it. More exactly, the invention relates to a new and improved device for achieving the sequential compression and release of the conduit.
• Peristaltic pumps are well-known and have been widely used in many fields, as they have a number of advantages. Thus, they can be used for pumping very different media from liquids of a low viscosity to more or less paste-like materials. Moreover, they can be made from materials which are insensitive to corrosive or abrasive constituents in the pumped medium. Another advantage is that the amount dosed can be adjusted very precisely and be varied continuously from zero to full capacity. Because of this, peristaltic pumps have been widely used in medicine, for instance at infusion of various preparations to a patient. A further advantage is here that it is easy to clean and sterilize those parts of the pump with which the pumped medium gets into contact. As the very pump means actually only consists of a piece of an elastic piping or hose this can be of a disposable type and be discarded after use. In this way a maximal freedom. of bacterial and other contamination is secured.
• This invention relates to a peristaltic pump comprising a conduit of an elastic material for feeding the medium to be pumped, and a number of means for compressing the piping and releasing the pressure in a given sequence to press the medium forward.
• the means for compression and release comprise projections extending from a disc or a base against which the conduit s pressed by the disc, and the conduit is arranged along at least that part of the periphery of the disc or of the base, from which the projections protrude.
• the disc is arranged to perform such a rocking movement that the projections in a given order press against the conduit and compress it, and to release the pressure against the conduit in the same order so that it lets the medium pass.
• the projections preferably consist of pins having a substantially round cross section, which are arranged substantially radially extending from the edge of the disc along at least a part of its periphery.
• the humber of the projections is at least three and in a suitable embodiment four pins are arranged in a substantially square disc with each two mutually parallel pins extending from two opposite edges of the disc. Also other emdobiments of the projections are possible as shown in the following.
• the expression "periphery" with regard to the disc is to be taken in a wide sense and is not merely restricted to a circular disc but relates to the circumference of discs of any suitable form.
• Fig. 1 is an exploded view of an embodiment of a pump according to the invention.
• Fig. 2 is a view of the rocking disc and
• Fig. 3 is a sectional view of a device for adjustment of the amount fed by the pump.
• Figs. 4 and 5 show additional embodiments of the invention.
• like details have been given the same reference numerals.
• a flexible piping or hose 1 for feeding the medium to be pumped is shown.
• the hose 1 rests against a solid base 2 and is held in its correct position thereon by shoulders 3.
• the pumping is effected by the rocking disc 4 which is provided with four pins 5, 6, 7, 8 extending from two opposite edges of the substantially square disc 4.
• the rocking movement of the disc is brought about by a helical spring arranged between the disc 4 and a drive motor 10.
• the spring rests with one of its ends against the upper side of the rocking disc 4 and is held in its position there by means of the guide means 11 or in any other suitable way.
• the spring is mounted with its other end in one end of an eccentric member 12, whose other end is joined to the shaft 13 of the drive motor 10.
• the rocking disc 4 is attached to an articulated joint member 13 at its lower side, such as by the threaded member 15 being screwed into the disc.
• the joint member 14 is made such that the rocking disc 4 can rock in all directions without being able to rotate and can for instance be a universal joint as schematically indicated in the drawing figure.
• the joint member can however also be a ball, and socket joint which allows rotation per se but where turning of the rocking disc 4 in the horizontal plane is prevented by the shape of the shoulders 3.
• the lower end of the articulated joint member 14 is attached to a shaft 16, which passes through a hole 17 in the base 2.
• the shaft 16 is attached to a device for setting and adjusting the position of the rocking disc, which device is generally designated by 18 and is described in closer detail in Fig. 3.
• Fig. 2 is a top view of the rocking disc. It is apparent that the disc is substantially square and that the four pins 5, 6, 7, 8 project from two opposite edges of the square and are substantially parallel to the two other opposite sides. Small deviations in this respect, however, are without importance for the function of the pump.
• the guide means 11 on the upper side of the rocking disc is also shown.
• the thickness of the rocking disc 4 and the exact position of the pins 5, 6, 7, 8 are substantially defined by the dimensions of the elastic conduit 1, which is to feed the pumped medium and by the compression and release of which the pumping effect arises, and can be easily established by one skilled in the art.
• Fig. 3 shows in detail a schematical sectional view of the device 18 for setting and adjusting the position of the rocking disc.
• the shaft 16 is shown, the upper end of which is attached to the joint member, such as by means of a thread 19.
• the shaft 16 is proviced with a guide 20, which guides the shaft in the hole 17 and prevents the shaft from being turned in this hole. This can also be achieved in different manners as is clearly evident to one skilled in the art.
• the hole 17 can e.g. have a cross section like a polygon, and the guide 20 can be shaped in a way suitable for this.
• the lower portion of the adjusting means 18 is designed as a knob 21 which has a central recess 22, from the bottom of which the central inner sleeve 23 protrudes.
• the inner sleeve 23 is provided with an internal thread, which receives an cuter thread en the lower portion 24 of the shaft 16.
• the shaft 16 can be screwed into the inner sleeve 23 to a varying depth.
• a guide bushing 25 is arranged around the inner sleeve 23 and is concentrical therewith, and between the guide bushing 25 and the inner sleeve 23 a spring 26 is arranged. The lower end of the spring rests against the bottom of the recess 22, and its upper end rests against an internal shoulder 27 in the guide bushing 23.
• the spring tends to urge the guide bushing 25 out of the recess 22. This is prevented by the support ring 28, which is preferably screwed onto the outer end of the inner sleeve. The upper end of the guide busing 25 rests against the underside of the base 2.
• the upper end of the spring 18 When the drive motor 10 is in operation, the upper end of the spring 18 will be forced by the eccentric member 12 to follow a circular orbit in substantially the same plane as the rocking disc. This movement will be transmitted as a rocking movement to the lower end of the spring, which rests against the rocking disc 4 so that a circular rocking movement is imparted also to the disc.
• the four pins 5, 6, 7, 8 in the rocking disc By the rocking movement, the four pins 5, 6, 7, 8 in the rocking disc will by turns press more strongly against the hose and compress it while the pin substantially diametrically opposed will release its pressure against the hose 1.
• the pins should be arranged in the rocking disc in such a way that in the rocking movement, the hose will always be compressed on at least one point.
• the joint member 14 a rocking movement is made possible in all directions at the same time as the rocking disc is prevented from rotating either by the construction of the joint member 14, or by the shape of the shoulders 3.
• the spring itself does not perform any rotating movement, but that its upper end, which is freely mounted in the eccentric member 12, is only moved around in a circular orbit.
• the conduit or the hose 1 for feeding the pumped medium is arranged so that the pins of the rocking disc can compress it in a given order.
• the hose is introduced from one side and placed around one of the shoulders 3 so that it is bent roundly.
• the pins of the rocking disc can compress the hose in turn before and after its bending around the shoulder 3.
• the hose rests against the solid base 2 so that a good support for the compression is obtained.
• the capacity of the pump is adjused by the adjusting means 18 as described in the following.
• the knob 21 By turning the knob 21, it will be possible to screw the threaded shaft 16 into the inner sleeve 23 to a varying depth.
• the shaft 16 is prevented by the guide 21 to follow the turning.
• the distance between the rocking disc 4 and the base 2 will be changed via the joint member 14, and consequently also the capacity of the pump, as the distance between the rocking disc and the base decides how great a movement (obliquity) can be effected by the rocking disc 4.
• the movement of the rocking disc is such that the hose is completely compressed under two pins and fully open under the opposite pins, the distance is at maximum, and accordingly also the pump capacity.
• the slanting of the rocking disc is also reduced and consequently also the flow in the hose.
• the hose is completely compressed by all four pins and no rocking movement can be performed by the rocking disc, and therefore the flow will be zero.
• the spring 26 placed in the recess 22 of the knob 21 between the inner sleeve 23 and the guide bushing 25 has several functions. As the knob 21 is urged upwards against the spring force, the shaft 16 and its associated rocking disc 4 will also be urged upwards. Thus, the hose 1 will be released from the pins of the recking disc and can then easily be removed and exchanged. There is nor risk of spillage from the hose when it is removed.
• the spring 26 can act as a safety means and prevent damage to the apparatus or hose breakage due to excess pressure if for instance a hose should be clogged or the pump operate against a closed valve. At a suitably selected spring force the effect may be obtained that the pump does not give a higher pressure than that permitted by the spring force. If this pressure is exceeded in the hose, the rocking disc 4 will be lifted against the spring force due to the pressure and, as a result, the pumping effect will cease. Accordingly damage to the device due to a uncontrollably high pressure is prevented.
• the spring force of the spring 26 can be adjusted by screwing the support ring 28 to a suitable position along the inner sleeve 23.
• the embodiment shown here is only an example and several modifications are possible within the scope of the inventive idea.
• the eccentric member 12 attached to the motor shaft 13 can for instance be provided with a spring-loaded wheel, which rolls against a circular roller path arranged on the upper side of the rocking disc 4.
• the rocking disc will in this way be given the rocking movement, which is the essential feature of the invention.
• a partly sectional view of a simpler embodiment of a pump according to the invention is shown.
• the hose 1 is arranged between the base 2 and the rocking disc 4, which is continuously urged against the hose and the base by means of a compression spring 29.
• the rocking disc 4 is extended upwards by a member 50, which, is provided with a cylindrical recess 51.
• an eccentric member 32 is mounted, which is driven eccentrically by the drive motor 10 via the rr.otcr shaft 15. The mounting of the eccentric member 32 in the recess
• rocking disc 31 is carried out by means of spherical bearing surfaces or arranged in some other way so that an angle is made possible between the motor shaft 13 and the extension member 30 of the rocking disc.
• the rocking disc is shown as simply mounted in a recess 33 in the base 2 by means of a pin 34, but it can of course also be connected with a joint member in a way similar to that shown in Fig. 1. It is possible to adjust the amount pumped by variation of the speed of the motor. This of course applies to all the embodiments shown.
• the rocking disc can be provided with projections in the form of pins in the same way as in Figs. 1 and 2, but the projections can also be formed as ridges on the underside of the rocking disc, which create the sequential compression of the hose at the movement of the rocking disc. It is also possible to arrange projections in the form of ridges on the base for the hose and to have the underside of the rocking disc smooth, and in certain cases it is even possible to have the base for the hose as well as the underside of the rocking disc smooth. If the rocking disc has a square or rectangular form as seen in a vertical direction and is given the rocking movement, the corners of the disc will act as projections and provide the sequential compression of the hose so that a pump effect is obtained.
• FIG. 5 is an exploded view of a pump according to the invention.
• This embodiment is somewhat similar to that shown in Fig. 1, but the drive of the rocking disc and its construction are different, as well as the guide for the rocking disc.
• the hose 1 is arranged on a base 2 and is guided by shoulders 3 in the same way as in the previously shown embodiments.
• the rocking disc 4 is provided with two edge areas 35 and 36 bent down perpendicularly, the downwardly directed edge portions 37, 38, 39 and 40 of which act as projections to compress the hose sequentially.
• the rocking disc is attached to a threaded shaft 16 by means of a bushing 41 via a thin music wire 42, which acts as a joint member in this case.
• the shaft 16 is provided with a. stationary guide 20, which fits into a guide hole 43 in a guide plate 53 and in this way prevents the shaft 16 from being turned, and its thread fits into a bushing 44, to which an adjusting knob 21 is attached.
• This knob is also provided with a helical spring 45 which is mounted between the knob 21 and the underside of the base plate 2.
• the shaft 16 can thus be screwed into the bushing to a varying length, and in this way the distance between the rocking disc and the base plate can be changed.
• the knob 21 with the bushing 44 and the shaft 16 can be pressed upwards against the spring 45 so that the hose 1 is completely released and can be removed, and at an excessively high pressure in the hose, the rocking disc will also be lifted against the spring pressure and the pumping effect will cease in the same way as described for the embodiment shown in Fig. 3.
• the rocking disc is driven by the drive motor 10, the shaft 13 of which is rigidly connected to a disc 46, which is provided with a downwardly directed, eccentrically arranged pin 47.
• the pin 47 is connected with a bearing 49 for the shaft pin 50 of the rocking disc via a draw spring 48, said shaft pin being secured in the bushing 41.
• the downwardly bent edge portions 35 and 56 of the rocking disc are guided in the recesses 51 and 52 of the guide plate 55, these recesses being so large that the rocking movement of the rocking disc becomes possible.
• the guide plate 55 is retained at a suitable distance, which is not critical, over the base 2 by suitable holding means not shown in the drawing.
• the embodiment shown in Fig. 5 has the advantage as compared with that shown in Fig. 1 that the energy consumption in operation is less, as hysteresis losses in the spring 9 (Fig. 1) are avoided. Moreover, the design of the adjusting means of the pump shown in Fig. 5 is simpler than that shown in Fig. 5, as the concentric guide sleeves and the enclosed spring are eliminated.
• the rocking disc need not be designed exactly as shown in the drawing figures.
• the number of projections or pins in the rocking disc or the base should be at least three for a pump effect to be obtained and in one such a case these pins can be arranged with a division of, for instance, 90 along the periphery of a circular rocking disc and act on the hose along its bent portion.
• the one of the two shoulders 5 around which the hose is placed is excluded and the other shoulder is designed for a suitable guidance of the hose.
• rocking discs with more than four pins and the modifications of the device which will then be necessary can be easily determined by one skilled in the art with a knowledge of the basic idea behind the invention.
• the disc as such in the rocking disc may be excluded and be replaced by a suitable framework construction through which the projections can act in a desired manner.
• a suitable framework construction through which the projections can act in a desired manner.
• Such an embodiment can for instance be designed as a vertical shaft, to which are directly attached pins, which extend perpendicularly from the vertical shaft and with a radial division of the horizontal plane. If an upper end of the shaft is made to follow a circular orbit in the horizontal plane, the imagined horizontal plane in which the pins are situated will perform a rocking movement in the same way as a disc of the previously described type and the pins can act on an elastic conduit in the same way as indicated above.
• the articulated joint member 14 can be made in any way that in combination with a guide for the rocking disc makes possible an unhindered rocking movement in all directions and prevents turning around a vertical, axis.
• various types of universal and ball joints can be used, but also other devices are possible, such as a flexible rubber coupling with a low stretchability.
• Other features of the invention can also be modified without going beyond the scope of the invention.
• the fundamental principle thereof is that a sequential compression and pressure release en a flexible conduit are obtained in such a way that projections, preferably arranged as protruding from a disc, which is given a rocking movement, are made to effect the compression and pressure release of the conduit. Additional modifications will easily be apparent to one skilled in the art.
• a pump of a peristaltic type is provided, the design of which is simple and which can be easily adjusted in respect of its capacity, allows an easy replacement of the flexible conduit and which is safe against detrimentally high pressures in the pump line. This involves great advantages as far as costs and safety in use are concerned, especially in the medical field.
• the use of the pump of the present invention is not merely restricted to this field but the pump can be used in any application where a pump of peristaltic type has been found to be suitable.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Reciprocating Pumps (AREA)
• Eye Examination Apparatus (AREA)

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Publications (1)

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ID=20342823

Family Applications (1)

Country Status (6)

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Citations (1)

Family Cites Families (4)

• 1981
  • 1981-01-07 SE SE8100044A patent/SE8100044L/ not_active Application Discontinuation
  • 1981-12-28 IL IL64669A patent/IL64669A0/xx unknown
• 1982
  • 1982-01-04 JP JP57500311A patent/JPS57502263A/ja active Pending
  • 1982-01-04 EP EP82850001A patent/EP0056019A1/en not_active Withdrawn
  • 1982-01-04 WO PCT/SE1982/000002 patent/WO1982002421A1/en active Application Filing
  • 1982-09-06 NO NO823003A patent/NO823003L/no unknown

Patent Citations (1)

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