FR2458694A1 - Miniature peristaltic pump with electronic speed regulator - has DC motor rotating pump wheel having electronic speed control with variable potentiometer - Google Patents

Abstract

The pump has a rotating wheel with peripheral rollers periodically compressing a flexible tube to pump the liquid. It is driven via a DC motor supplied from a battery group, which can be coupled to the mains for recharging and/or for steady operation of the pump. An electronic speed regulator is inserted between the battery group and the DC motor, to provide constant speed regulation. The speed variation is obtained with a very slight drop in voltage, for optimum utilisation of the batteries. Pref. the electronic speed regulator has a ballast transistor (T1) in the supply line to the motor controlled by a transistor amplifier (T2,T3). A resistor (R1) limits the current for the ballast transistor (T1) and a resistive voltage divider including a potentiometer (P) used to obtain the required speed regulation.

Description

The present invention relates to a small size peristaltic pump.

In pumps of this type, pumping is carried out by crushing a section of a flexible tube under the action of one or more rollers carried by a wheel actuated by a drive member.

Such pumps have imposed themselves in the medical field due to the fact that the liquid to be pumped, blood, nutritional liquid or the like is not in contact with the rubbing surfaces.

Another argument in favor of these pumps is their Sil ple design which makes it possible to reduce their dimensions which is an important advantage in the medical field in particular when such pumps must be used for parenteral nutrition in ambulatory mode.

Parenteral nutrition on an outpatient basis makes it possible to feed the patients by pulsing in the blood a liquid nutritive solution contained in a vacuum bag which the patient can carry on the chest.

This method of recent application allows the patient having to undergo such treatments not to be immobilized in hospital.

The peristaltic pumps offered for this purpose are designed to be able to operate independently by means of accumulators.

These existing pumps however have a number of drawbacks.

The flow rate of this type of pump being linked to the speed of rotation of the roller wheel, it is necessary to provide these pumps with speed variators making it possible to adapt the flow rate according to the user used.

However, the speed variation devices used do not offer a sufficiently wide speed range.

This results in insufficient nutrition or an extended feeding time and a risk of accident if the flow rate is too high.

The autonomy of these pumps in ambulatory operation is only a few hours because of the volume of the accumulators and their weight linked to those of the pump which must necessarily be reduced.

The design of most of these pumps is such that the tube is tensioned around the roller wheel and that in conjunction with the crushing of the tube occurs its stretching which prevents reaching a high pressure and which requires a rapid rotation of the impeller to obtain satisfactory flow.

In addition, these known pumps are difficult to operate and only operate satisfactorily with a predetermined flexible tube diameter.

The present invention aims to obviate the above drawbacks by providing a pump of small dimensions therefore easy to carry in ambulatory use, of simplified implementation and which however offers autonomy of several tens of hours.

The present invention further aims to provide a pump which offers
e a wide range of adjustment of the pumping speed and the flow rate which also offers great safety in use.

For this purpose, the pump according to the invention of small dimensions of the peristaltic type in which the liquid is pumped by crushing a portion of a flexible tube by means of a roller wheel actuated in rotation by a reducing motor assembly with direct current supplied by a group of accumulators capable of being connected to the network for recharging and / or operating the pump in a fixed position is essentially characterized by an electronic speed regulator module interposed between the energy source and the motor so that the speed regulation can be obtained constantly and with a range of speed variations tended with a low voltage drop which allows the op timbal use of accumulators making it possible to reduce their dimensions and volumes and making the use of said pump which is particularly advantageous in parenteral nutrition on an outpatient basis.

According to another characteristic of the invention, the electronic control module comprises electronic control members keeping the current in the supply circuit constant, an adjustable voltage divider assembly making it possible to vary the speed of the motor and the flow rate of the pump. and a safety group of tintés to avoid the runaway of the engine under the effect of an excessive tension in the event of failure of the regulating organs.

According to another characteristic of the invention, the case has the shape of a flat rectangular parallelepiped, the roller wheel rotates on a small side of said case and a movable cover on the short side acts as a pump body around the wheel i with rollers, the said cover being provided with a semi-circular ramp against which the flexible tube is crushed, which makes it possible to obtain a high pressure without damaging elongation of the tube.

Other advantages and characteristics of the invention will appear on reading the following description of an embodiment given by way of nonlimiting example and illustrated by the accompanying drawings in which - Figure 1 is a plan view of the pump according to the invention.

- Figure 2 is a sectional view of Figure 1.

- Figure 3 is a schematic view of the circuit and the module
speed regulator.

- Figure 4 is a front view of the pump according to the invention.

- Figure 5 is a partial sectional view of Figure 1 (at
pump body level).

- Figure 6 is a front view of the pump body cover.

- Figure 7 is a front view in section of the roller wheel.

As shown, the pump according to the invention comprises a t-shaped box of rectangular parallelepiped shape which is not very thick, constituted by assembly by means of screws 2 of two shells coming from soft lay.

The housing 1 has on its rear face 3 a hollow housing 4 and on its small front side 5 a larger upper section with boss 6 on which and against which is blocked a pump body cover as described above.

Inside the case 1 are arranged a reduction motor assembly 7, a group of accumulators 8, a socket 9 for supplying said accumulators by means of a transformer charger not shown from the network and a regulator module speed 10 with potentiometer.

The electric motor is of the direct current type known per se, the shaft 11 of which projects from the housing on the small front side thereof.

The speed regulator module as shown in the diagram in FIG. 3 comprises on the motor supply line a "ballast" transistor 11 controlled by an amplifier constituted by the transistors T2 and T3.

A resistor R1 limits the control current of T1 to an optimal value and a resistor R2 fixes the operating point of the transistor T3.

The assembly according to the invention comprises a voltage divider constituted by the resistors R3 and R4 and the potentiometer P.

Said voltage divider makes it possible to apply to the input of transistor T3 a fraction of the motor supply voltage according to the setting of the potentiometer.

This supply voltage can stabilize between for example 1.5 and 4.5 volts approximately, which allows, the current being maintained regulated by the ballast transistor Ti, by varying the supply voltage to vary the speed of the motor and pump flow.

The mounting of the pump speed regulator module according to the invention also includes a safety group which consists of a F-rated fuse mounted on the motor supply line and a Zener DZ diode.

Fuse F is preferably a fuse rated at 100 mA.

 This safety group has the property of behaving like a circuit breaker causing the fuse F to blow as soon as the voltage across its terminals exceeds 5 to 6 volts.

Therefore by interrupting the supply is avoided the runaway of the engine under the effect of excessive tension.

This case can arise when a failure of the plug-in transformer charger on the domestic network simultaneously with a failure of the regulator in the event that the accumulators would no longer be able to limit the excess voltage due to their aging for example .

The regulator used as described has, among other advantages, that of working with a very low voltage drop, if necessary it is possible to reach an output of the order of 4.7 with a voltage of 4.8 V in Entrance.

Therefore the capacity of the batteries is used to the maximum which authorizes the use of batteries of reduced dimensions.

The charger device supplied with the device is also provided with safety means and in particular means for automatically stopping overload operation.

The potentiometer P is controlled by the knurled rotary button 12 donations the recess 4 of the back of the device according to a graduation which from the stop / on position allows to obtain a range comprising by vexez ple ten different speeds and therefore ten different flow rates likely to go according to the internal diameter of the flexible tube from 1/2 liter to 3 liters in 12 hours.

it goes without saying that in the case where the pump according to the invention is intended to be used in pediatrics the flow rate n will be limited.

On the small front side 5 of the box at the level of the boss 6 of larger section is wedged on the output shaft 11 of the reduction motor unit a wheel 13 provided with peripheral radial rollers 14.

The wheel 13 can be produced by assembling two flanges made of a synthetic material between which the rollers 14 are trapped as shown in the drawings the wheel consists of a male flange 15 with rear annular shoulder 16 and pins 17 which penetrate into corresponding orifices 18 of a flange 19 female the.

Each of the flanges is provided with a circular groove 20, the said grooves coming opposite one another during assembly.

At the level of the gap, circular grooves and transverse to them are provided for molding oblong slots 21 radial relative to the center of each of the flanges.

Preferably three oblong openings are produced on each of the flanges according to an angular distribution of 1200, the openings of one of the end shields coming opposite the mounting of the openings of the other.

In the oblong slots are threaded the axes 22 of the rollers 14 which protrude from the wheel.

Preferably the cylindrical rollers have a larger diameter at their ends than in the middle.

In the grooves 20 is disposed under each of the rollers an elastic member 22 whose function is to push in pressure the corresponding roller towards the periphery of the flange while allowing said roller to go back.

This arrangement makes it possible to adapt to the pump according to the invention tubes of different diameters and therefore in the case where the pump is used in parenteral nutrition or in infusion to be able to use the various materials found on the market.

On the front face of the pump housing according to the invention, under the roller wheel, a stud 23 is produced perpendicular to the wall 5 and of substantially rectangular shape, the sides and the bottom wall of which have a bevelled edge 24.

Under the lower wall of the tenon at the end of its beveled skin 24 is formed a transverse groove 25.

Through the tenon 23 are made two parallel vertical notches 26 arranged on either side of its center and whose inlet 26A is tightened.

These notches receive and block the flexible pipe as will be described later.

At the top of the front face 5 on the boss 6 is formed a hollow or mortise reservation 27 whose sides are provided with an axial bore.

In the mortise 27 is housed a tenon 28 of a cover 29 forming
pump body.

A piercing of the tenon opposite that of the sides of the mortise makes it possible to fix the cover on the casing while leaving it the possibility of pivoting.

The cover is in the form of a recessed oblong box provided with a transparent front wall 30 of which an orthogonal internal bottom wall 31 corresponding to the position of the stud 23 is provided with a central tab 32 with rib 33 snap-in the lower groove of the post 23.

Beyond the internal orthogonal wall 31, the front wall 30 allows the finger to open or close the cover.

The side walls 34 of the cover conform to the contours of the front face 5 and of its boss 6.

To this end, the walls 34 are tightened beyond the internal recess occupied by the roller wheel.

The upper part of the wall 34 of the cover constituting the pump body is provided with a semi-circular ramp 35 which surrounds the roller wheel on its upper half and descends below its diameter.

On either side of the ramp 35 a bevel 36 connects said ramp to the inner wall of the cover.

The ramp 35 is concentric with the roller wheel and its diameter is very slightly greater than that of said roller wheel so that by rotation of the latter the flexible pipe is compressed against the ramp which ensures pumping as and as the rollers pass.

The implementation of the pump according to the invention is carried out as follows
The hood is raised, the flexible tube is put in place around the roller wheel, it is locked in the two notches of the lug on the front of the case by blocking its stop under the left notch and is pulled down. by the user without tension.

By lowering the cover, the tube is blocked between the roller wheel and the ramp of said cover.

it is then possible to start the pump by operating the potentiometer.

According to another embodiment not shown to simplify the drawing, the pump body cover is made not pivoting but sliding on the front face of the housing in slides formed on its sides.

 The pump according to the invention is of particularly reduced size and weight so that it is possible for the user to use it in a fixed position, or in the case of a self-propelled portable use, to carry it in its pocket or to attach it to his belt, the said pump being provided with flanges for this purpose.

 The pump housing is provided with a means which can be as shown in FIG. 2, a bore 37 allowing the attachment of a strap, not shown, which facilitates the handling and fixing of the pump on any support such as for example a tette. of bed, a gallows or more simply a hook.

In a fixed position the pump is connected to the electrical network by means of the transformer-charger and it can operate for an unlimited period.

In ambulatory operation, the autonomy is several tens of hours the electronic regulation module allowing optimum use of the stored energy.

The pump according to the invention can receive arrangements and variants in the field of technical equivalents without departing from the scope of this patent.

Claims (1)

CLAIMS Rîl Small size pump of the peristaltic type in which the liquid is pumped by crushing a portion of a flexible tube by means of a roller wheel actuated in rotation by a DC motor-reducer assembly fed by a grou . eg accumulators capable of stretching connected to the network for recharging and / or operating the pump in a fixed position characterized by an electronic speed regulator module interposed between the accumulator group and the reduction motor group so that the regulation speed is obtained constantly and following a wide range of speed variations with a very low voltage drop which allows optimum use of accumulators allowing their dimensions and volumes to be reduced, making the use of said pump which is particularly advantageous in ambulatory parenteral nutrition or at a fixed position. R2 / Pump according to Claim I, characterized in that the electronic regulation module comprises electronic regulation organs keeping the current in the circuit constant, an adjustable voltage divider assembly making it possible to obtain a variation of the motor speed and of the flow of the pump and a safety group designed to prevent motor runaway from excessive tension. R3 / Pump according to claim 1 characterized in that the pump housing is in the form of a flat rectangular parallelepiped, that the roller wheel rotates on a small side of said case and that a movable cover on the said small side acts as a pump body around the roller wheel. R4 / Pump according to claim 1 and claim 2, characterizing that the movable cover is provided with an internal semi-circular ramp which surrounds the upper half of the gated wheel against which the portion of flexible tube is compressed. R5 / Pump according to claim 1 and claim 3 caractFrisJ in that the flexible tube is held under the roller wheel by locking in two notches of a stud perpendicular to the small side of the housing on which the said wheel rotates. R6 / Pump according to claim 1 and each of the claims 3.4 and 5 characterized in that the cover is hinged to the wood  tier and that it cooperates in blocking with the tenon of the small side of the said box on which the roller wheel rotates. R7 / Pump according to claim 1 and claim 3 character in that the rollers are movable under pressure by means of a  elastic member in oblong lights of the mena wheel  gée along spokes of the said wheel so that by enfon cement rollers of flexible tubes of different diameters  can be pressed against the hood railing.