Portable peristaltic pump

Details Portable peristaltic pump Portable peristaltic pump

1999-03-08

2000-08-29

Walberg, Teresa

Pumps

Expansible chamber type

Elongated flexible chamber wall progressively deformed

417477, 417374, F04B 4308

Patent

active

061098957

DESCRIPTION:

BRIEF SUMMARY
This invention refers to portable peristaltic pumps. More specifically, it concerns a miniature peristaltic pump for the injection of drug solutions.
Miniature pumps or micropumps for medical use have been available for several years. Light and of small size, they can be worn discreetly and comfortably by the patient and permit the administration of controlled quantities of drug solutions to said patient, either subcutaneously or intravenously, continuously or according to a specific program, without his having to be confined to bed or hooked up to a cumbersome, costly and noisy machine.
Such pumps are most often of the rotary peristaltic type whose principle consists in having a flexible plastic tubing connected to a reservoir containing the solution and having it pressed locally against a rounded-off support piece by means of pressure rollers mounted on a rotor driven by a motor operating through a gear train. The liquid is thus drawn up from the reservoir and discharged toward the outlet to be injected into the patient.
Patents EP 388 787, EP 447 909, EP 521 184 and WO 94/06491 describe miniature peristaltic pumps of this type.
When designing such pumps, it is particularly important to be concerned about the problem presented by the discharging of the tubing, i.e. the discharge of any air it still contains, before inserting the needle into the patient. The rotor's rotation speed being very slow, generally less than 1 rpm, this operation must, in order not to take too much time, be done by making the rotor turn rapidly by external means. Patent EP 388 787 discloses a wheel which is part of the rotor and includes a series of holes into which one can put, for example, the point of a ballpoint pen to turn the wheel rapidly. That solution is certainly an interesting one, but no arrangement has been provided to keep this operation from damaging the gear train.
The document JP 58 070079 discloses, furthermore, a peristaltic pump provided with a disengaging system which enables the motor to be disengaged from the head of the pump. With the motor disengaged, the head of the pump may be turned more rapidly through a manual action.
However, it is to be noted that the disengagement is carried out by translating a control rod, which renders operation difficult.
Another major problem occurs during the design of a miniature peristaltic pump. The problem is that of the coupling between the rollers and the tubing being pressed by the rollers against the support piece.
Measurements have shown that the minimum pressure on a roller having a diameter of 5 mm, necessary to make a liquid flow in plastic tubing with an internal diameter of 1.47 mm and an external diameter of 1.96 mm is 95 grams. The corresponding tensile force exerted by the roller is 15 grams. The pressure on the roller may increase up to 150 grams without proportionally increasing the tensile force, which then only increases from 15 to 20 grams. However, beyond that limit, the tensile force increases very rapidly. In fact, it increases to 50 grams for a pressure of 200 grams, after which measurements become impossible.
Such observations are easily explained by the fact that once the tubing has been squeezed until it is completely sealed, any increase in pressure causes deformation of the plastic material and the corresponding tensile force then increases in relation to its elasticity module.
Thus, any variation in the position of the roller in relation to the tubing beyond that which achieves its closure, puts a heavy load on the roller-carrying rotor and its motor, which quickly causes jamming and therefore stopping of the pump. The effect is all the more pronounced in the miniature pumps that are obviously equipped with less powerful motors than the non-portable pumps.
Contrary to that, any variation in the position of the roller below the one that enables the complete closure of the tubing does not permit a normal flow of the liquid.
It is thus very important, in order to obtain a reliably functioning pump, that the distance separating the roller from the

REFERENCES:
patent: 3816035 (1974-06-01), Hutchisson
patent: 3960466 (1976-06-01), Taylor
patent: 4083777 (1978-04-01), Hutchisson
patent: 4210138 (1980-07-01), Jess et al.
patent: 4229299 (1980-10-01), Savitz et al.
patent: 4558996 (1985-12-01), Becker
patent: 4599055 (1986-07-01), Dykstra
patent: 4705464 (1987-11-01), Arimond
patent: 5083908 (1992-01-01), Gagnebin et al.
patent: 5250027 (1993-10-01), Lewis et al.
patent: 5266013 (1993-11-01), Aubert et al.
patent: 5460493 (1995-10-01), Deniega et al.
patent: 5655897 (1997-08-01), Neffel et al.
patent: 5752813 (1998-05-01), Tyner et al.

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