CA2122600C

CA2122600C - A pump for biological fluids

Info

Publication number: CA2122600C
Application number: CA002122600A
Authority: CA
Inventors: Valery Viktorovich Skobelev; Mikhail Alexandrovich Slivin; Evgeny Afanasievich Selezov; Viktor Grigorievich Kabakov; Gennady Sergeevich Puzikov
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-02
Filing date: 1992-09-02
Publication date: 1998-10-13
Anticipated expiration: 2012-09-02
Also published as: DE4295020C2; FR2716940A1; DE4295020T1; US5586872A; SE511883C2; CA2122600A1; FR2716940B1; CH685675A5; SE9401476D0; SE9401476L; WO1994005345A1

Abstract

The invention relates to a pump for biological fluids, for example for blood transference by pump. The pump according to the invention comproses a housing (1) in which there are placed at least one resilient tube (3) for passing biological fluid, and an operating head (5) rotated in the direction of fluid transference and including at least one roller member (6) to bear against the tube (3), said roller member (or each roller member) comprising at least two rollers (7,8) positioned in series so that the roller (7) of said roller member which is preceding in the direction of the operating head rotation allows greater tube (3) aperture than does the roller (8) of the same member (6) that follows.
The pump has simple and convenient means for adjusting the degree of compressing the tube (3) by the rollers (7,8) and ensures blood transfusion causing practically no damage to the blood cells.
(Fig.1)

Description

, 2l~26no A PUMP FOR BIOLOGICAL FLUIDS
The present invention relates to a pump for transfering biological fluids, comprising a housing which includes at least one resilient tube for passing through 5 said tube biological fluid subject to transference by -~
pump, and an operating head which is rotatable in the direction of fluid tranference and contains at least one roller member to bear against said tube.
The pumps of such type are known in the art for a relatively considerable stretch of time and are used at present in the medicine for transfering by pump such susceptible to mechanical actions biological fluids as blood.
Operation of these pumps is based on that while an operating head is rotated, its roller member (or members) travels along the resilient tube in the direction of fluid transference, compressing the tube at the point of its contact with rollers. Displacement of contra~ted section of the tube's aperture results in pushing through the fluid along the tube in a manner which is similar to pushing through, for example, food during peristalsis (periodic wave-like contraction) of intestines. According-ly, in view of their operating principle, the pumps of :
this type are also called "peristaltic". ~
The major task to be solved by said pumps consists in ~.
ensuring effective transference of blood at a requred flow -i rate (volume to time), minimally affecting the transferred biological fluid. This latter condition is especially important because blood contains form elements such as erythrocytes, which are easily destructible by mechanical actions (impacts, shaking, vibration etc.). Destruction of blood form elements portion (also known a~s "hemolysis") unavoidably arising during transferènce of blood to a patient, leads, particularly, to such an undesirable phenomenon as aftertransfusion fever - a result of the human body~s reaction to dissolved substances in blood, ,.. ,, ~:~,. -::. ,; . -. .
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21226~0 which have separated from erythrocytes and other form elements destructed during blood transference. ~ ;
Said reaction of the patient's body is stronger, the greater the amount of blood subject to transference to the patient, and thus, the more dramatic is the condition of a person and the greater is the quantity of blood re4uired for transfusion, the more dangerous is said undesirable phenomenon. This problem is substantially solved by the pumps of above type in which blood transference is performed without abrupt mechanical actions, i.e.
peristaltically. Said problem, however, has not been completely eliminated until now, and even while using the most advanced blood transfusion apparatus, the medica]
personnel now and again register the patient's fever condition after transfering considerable quantities of blood, and they have to make additional efforts to eliminate these aftereffects.
Specifically, in the description attachment to US
patent No. 3447478 ( Int.Cl.F 04 ~ 43/08), there is disclosed a "peristaltic" pump for blood transfusion, which comprises said features, some of its roller members completely pinching the tube for tranfering fluid, other roller members serving to adjust the amount of transferred fluid per unit of time by incomplete contraction of tube - 25 aperture.
In the description of another US patent No. 4012177, there is disclosed a similar pump which has same application and is provided with an improved construction of tube allowin~ to reduce hemolysis during blood transference through the same.
None of the prior art pumps of peristaltic type ensure complete elimination of hemolysis, and the pumps mentioned hereinabove are no exception. ~till there remains an urgent necessity to create a pump capable of tranfering blood practically without desrtuction of form elements ("hemolysi~

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-21226~0 Besides, the known pumps require relatively fre~uent replacement of the tube due to its wear which mearls additional problems to the user.
Thus, the object of the present invention is to create such peristaltic pump which would ensure effective transference of blood, minimally affecting its form elements.
Another object of the invention resides in solving the task of improving reliability of the pump and reducing the rate of its wear.
Said objects are accomplished as follows. The pump of the above type according to the invention is distinctive from the prior art technical solution by that each roller member comprises at least two rollers placed in series so that the roller which is preceding in the direction of rotor rotation permits to have greater aperture of said tube for tranference in comparison with the roller of the same roller member which follows.
Said distinctions permit blood transfusion with an incomplete pinching of resilient tube, and, hence, without destruction of form elements of blood, without reducing the pump's flow rate. The first hydraulic wave formed by the first roller of the roller member creates in front of' the first roller an elevated pressure region, the value of - 25 such pressure being less than in front of the second roller, which allows smaller aperture of resilient tube.
Thus smoothly obtained build-up of pressure secures minimal damage to blood form elements.
Preferably, between said tube and roller members there is placed a gasket of resilient material, one side of said gasket being the rolling surface of said rollers, another side bearing on the tube~
Said roller members can be mounted immediately or, the operating head; however, in the preferred embodiment they are connected to the operating head by means of a carrier.
The user will find it convenient if the pump is -. ~, : , ~ :
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, ' ' '' --' 2~226~0 provided with means for adjusting the degree of compression of said tube, said means prefer~bly to be mounted on the operating head. Such means for adjusting the tube compression degree can comprise a turnable and retainable eccentric placed coaxially with the operating head and coupled with roller member (members).
Means for retaining said eccentic usually comprises simple arrestment members, e.g. pins or balls.
The roller of the roller member which is preceding in the direction of rotation is preferably provided with another (second) means for adjusting the degree of compression of the tube by changing the position of this roller in relation to the carrier. In this embodiment, said second means can be most conveniently arranged in the form of a figurate or straight slot in the carrier to receive the axis of the roller preceding in the direction of rotation.
Said resilient ~asket usually comprises a belt made of elastic material, though it can be of annulus or cylinder shape.
It is clear that the concept of the present invention disclosed mainly in the dependent claims, can be developed to include greater number of operating heads in one pump with obtainment of blood transfusion station for several f 25 patients. An example of such development of the invention is given below, wherein the pump of the invention comprises two tubes and two operating heads.
The invention is further illustrated by non-limiting embodiments with reference to drawings, wherein:
Fig. 1 is a schematic general view of the pump accordin~ to the invention, in partial cross-section, with side cover removed;
Fig. 2 is a cross-section along line A-A of Fig. 1;
Fig. 3 is an expanded view, in partial cross-section, of eccentric mechanism of the means for adjusting the degree of compression of the tube by the rollers;

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, ~ , - . : ,, --" 21226~0 Fig. 4 is a dial of manual adjustl~nt of the eccentric position, view along line B-B of Fig. 3;
Fig. 5 is a carrier back view along line C-C of Fig.
3;
Fig. 6 shows the second means for adjusting the position change of the precedin~ roller in the direction of rotation; and Fig. 7 is a schematic view of an alternative embodiment of the pump according to the invention as a station with two tubes and two operating heads and having a common drive.
Fig. 1 is a schematic general view of the pump according to the invention, and Fig. 2 is a cross-section of the same. From these drawings it becomes apparent that inside a housing (1) having a cylinder bore (2) there is placed a resilient tube (3) for passing through it biological fluid (blood), said tube being made of material which is traditional in such devices, bearing no effect on the transferred fluid and capable of multiple sterilization, for example, of silicon.
To reliably retain the tube (3) in a fixed position, there are provided in the housing suitable for the purpose traditional means, for exampe, recesses or grooves, which correspond to the tube dimensions and are provided by boring or otherwise. In the inner space of the housing (1) there is rotatably mounted on a shaft (4) in the direction of fluid transference ( as shown in the drawing - clock-wise), an operating head (5).
The operating head (5) is provided in the present example with two symmetrically placed roller members (6).
According to the invention, each roller member ~6) comprises at least two rollers (7 and 8) placed in series so that the preceding roller (7) or the so-called first roller in the direction of the operating head (5) rotation allows greater aperture of the tube (3) than that allowed by the following or the so-called second roller (8) of the ,.: :. - ~ : :.

-' 21226~0 same roller member. This feature which determines the major concept of the invention, has been realized in the embodiment shown in Fig. 1, by corresponding arrangement of the first and the second roller (7,8) axes on levers (9) of a carrier (10) connecting these rollers to the rotatable operating head. The presence of the carrier (10) is also preferable to facilitate adjustement of distance between the roller members (~) and the operating head (5) to enable the rollers (7,8) perform the re4uired reduction of the tube (3) aperture at the point of contact, and ensure that distance 1 1 is greater than distance 1 2.
However, it is easy to imagine a pump according to the invention wherein said condition of changing the tube (3) aperture ( ~ 2) would be carried out diff'erently, e.g. owing to different diameter of the rollers (7,8).
Such alternatives of construction are not described here in greater detail because they remain within the scope of the invention and are quite obvious for anybody specializing in the art.
In exactly the same manner it is possible to use even n~re than two rollers in each roller member, since even with a greater number of rollers, the main condition ~ 1 ~ 2 of claim 1 of the invention is quite realizable. The only criterion when increasing the number of rollers in each roller member (upto three and more) is the expediency of such modernization in view of structural features of specific pump (e.g. its dimensions).
The operating head (5) is removably mounted on the shaft (4) and fixed to it by the aid of a threaded member (nut 11) and has a slot (12) (vide Fig. 5) for transfering a turning moment of the operating head to the carrier (10).
Fig. 3 shows a means for adjusting the tube (3) compression degree secured by rollers (~,~), which comprises an eccentric mechanism, including an eccentric (13) mounted coaxially to the operating head (5), and a means for its rotating and retaining. The eccentric (13) . . , . ~ .

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~-' 21226~0 can swing over its own axis (14) to make a certain angle by the aid of a manual adjustment dial (lb) having finger patterns (16) to facilitate its employment by the user (vide Fig. 1) and to be retained in this position with the help of balls (17) entering the openings (or depressions) (18) of a retaining disc (15 [vide Figs. 2 and 4]). The retaining openings (18) are distributed over the disc (15) circumference at a certain interval, e.~. at such interval which corresponds to radial displacement of' the roller member (6) of 0.15 mm. Position of the eccentric (13) as well its change, and, hence, the change of the distance from the roller member (6) to the inner surface (2) of the housing (1) which is responsible for the tube ~3) compression degree, are monitored by the aid of a scale ~19) which is visible through a window (20) of the disc (15).
The turnable eccentric (cam) (13) interacts with levers (9) of the roller members (6). Said levers are spring-loaded (by springs 21) and rotatably mounted on the carrier (10) on axes t22). Thus, when turning the retaining disc (15) by a desired angle controlled by means of the scale (19) which is visible through the window (20) of the disc (15), the eccentric (13) makes a turn, an the levers (9) are displaced thereby securing the required change of the tube (3) compression degree by the aid of the rollers (7,8).
Fig. 6 shows ~n alternative embodiment of the invention, which is provided with a ~asket ~23) and the second means for adjusting the position of the first roller (7). Between the tube (3) and the roller members (6) there is placed the gasket (23) made of elastic material, one side of said gasket being the rolling surface of the rollers (7 and 8), a~other side bearing on the tube (3). Said gasket helps to reduce wear of the tube (3), it excludes development of tensile forces which would exp~nd the tube, ensures a more continuous wave-like , ~,, , :

21226~0 deformation of the tube (3) walls when the rollers roll on the tube. The second (additional) means for adjusting the position of the first roller (7) comprises a slot (24) obtained in the lever (9). The slot (24) receives the axis (25) of the first roller (7) with a possibility of its retaining in the desired position. The member (25) can also be embodied in the form of an eccentric, which gives the user additional possibilities in adjusting the pump. The direction of the slot (24) which is sloping and not radial as in US patent No.3447478 offers additional advantages ~y allowing the user to achieve ~reater accuracy of adjustment. In addition, in the pump of the invention, this second means of adjustment also avails of such an advantage that the adjustment of the first roller (7) position without changing the second roller (8) position allows to choose the value~ 2) for - creating a laminar flow of fluid in the tube without vortices and cavitation in the zone where ~he tube is compres~ed by the rollers (7,8). The means of adjustment shown in the description permit to widen the scope of application of the pump according to the invention, mah~ing it more versatile owing to the fact that now it becomes possible to easily regulate the pump without changing the fluid viscosity factor, the flow rate, as well as when replacing the tube which can possibly result in the ~hange of the tube resilience, its passable section etc.
Finally, Fig. 7 is a schematic view of the blood transfusion station according to the present invention.
The central drive (26) rotates the two operating heads (6' 30 and 6'') placed symmetrically to transfer blood through the tubes (3' and 3r~)~ It is clear that the operatirlg heads and the tubes can number more ~han two. And as the respective housing and drive embodiments are already beyond the scope of the inventive concept, their details are not considered here.

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g It will be noted that the above exemplary embodiments are not limiting the present invention which can be developed by a specialist in the art without deviation from the essence of the invention cited in the claims 5 attached hereto. ;

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pump for biological fluids comprising a housing which includes at least, - one resilient tube for passing through biological fluid, and - an operating head which is rotatable in the direction of fluid tranference by pump and which contains at least one roller member to bear against said tube, characterized in that, the roller member comprises at least two rollers placed in series so that the roller of said roller member which is preceding in the direction of the operating head rotation has a greater aperture of said tube for tranference in comparison with the roller of the same member which follows, and wherein the pump is provided with a means for adjusting the degree of compression of said tube by the aid of rollers, said means being mounted in the region of the operating head, said means for adjusting the degree of compression of the tube comprises a turnable and retainable eccentric placed coaxially with the operating head and coupled with said at least one roller member.

2. The pump of claim 1, characterized in that between said tube and the roller members there is placed an elastic gasket, one side of which being the rolling surface of said rollers, another side bearing on said tube.

3 The pump of claim 1 or 2, characterized in that said roller member has a carrier connecting the rollers to the operating head.

4. The pump of claim 1, characterized in that the means for retaining said eccentric comprises arrestment members.

5. The pump of claim 1, characterized in that the roller of said roller member which is preceding in the direction of rotation has a second adjustment means for changing the position of this roller in relation to a carrier lever.

6. The pump of claim 5, characterized in that said second means for adjusting the degree of compression of said tube is arranged in the form of a figurate or straight slot in the carrier lever to receive the axis of the roller preceding in the direction of roller movement.

7. The pump of claim 2, characterized in that said gasket comprises an elastic belt.

8. The pump of claim 1, characterized in that it has two tubes and two operating heads positioned accordingly with a common drive.

9. The pump of claim 6, characterized in that said second adjustment means comprises an eccentric.